climate change myths and realities

Climate Change

Myths & Realities

Dr. S. Jeevananda Reddy

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Climate Change: Myths & Realities i Dr. S Jeevananda Reddy

Climate Change: Myths & Realities

Dr. S. Jeevananda Reddy

Hyderabad4th November, 2008

Climate Change: Myths & Realities ii Dr. S Jeevananda Reddy

Climate Change: Myths & Realities iii Dr. S Jeevananda Reddy

Table of ContentsPreface

Chapter 1: Earth’s Atmosphere

Chapter 2: Ozone Depletion

Chapter 3: Solar Radiation

Chapter 4: Weather & Climate

Chapter 5: Climate Change

Chapter 6: Systematic Variations

Chapter 7: Ecological Change

Chapter 8: Global Warming

Chapter 9: Extreme Weather & Climate Events

Summary

References

Annexure

I. Major Air Pollutants

List of Tables

1. Sky colours vs wavelengths

2. Most polluted cities by PM in 2004

3. Regression parameters vs Calendar months

4. Variation of “a” and “b” with seasons

5. Monthly Cyclonic disturbances in Arabian Sea & Bay of Bengal during

1891-1990

6. Estimated amplitudes and phase angles of four cycles in Fortaleza rainfall

data series

7. Estimated amplitudes and phase angles of Durban & Catuane rainfall data

series

8. Estimated number of Vehicles vs Population

9. Temporal variation of the irrigated area in the three sub-divisions of AP

10. Number of years under different groups of Typhoon days vs all- India

Summer Monsoon Rainfall during 1959-1991 [26-years]

11. Average rainfall amounts & C.V.s in the three meteorological sub-divisions

of AP during 1871-1994

12. Extreme events of rainfall & dates of onset in AP during 1871-1994

13. Percent average rainfall in the three sub-divisions of AP during 1987-1990

14. Monthly and daily highest rainfall of Cochin

Climate Change: Myths & Realities iv Dr. S Jeevananda Reddy

List of Figures

1a. Atmosphere layers

1b. Atmospheric layers vs Temperature pattern

1c. Latitudinal distribution of Tropopause level

2a. Solar Radiation Spectrum

2b. Sources of stratospheric chlorine

2c. Time series of the lowest values in ozone hole as measured by TOMS

2d. Image of the largest Antarctic ozone hole (September 2006)

2e. Annual march of Antarctic total ozone in Summer & Spring

2f. Annual March of Arctic total ozone in Summer & Winter

2g. Seasonal variation of Antarctic ozone

2h. Annual march of total ozone variations with latitudes

3a. Variation of Solar radiation with latitude & seasons on the top of the atmosphere

3b. Generalized Earth’s radiation budget

3c. Variation ϕij with Calendar months (j = January to December in Northern

Hemisphere, respectively refer to July to June of Southern Hemisphere & i =

1 to 3 respectively for inland, coastal & hill stations]

3d. Rt distribution over India for four representative months

3e. Rn distribution over India for four representative months

3f. Rt distribution over northeast Brazil for the twelve months

4a. Climates of the World — Koppen’s classification

4b. Primary storm tracks

4c. Climates of India — Koppen’s classification

4d. Monsoon onset pattern in India

4e. Rainfall regimes in India

4f. Temperature regimes in India

4g. Drought Prone areas in India

4h. Planting hazard zones in India

5a. Average annual change in climate in response to doubled carbon dioxide

(expected by 2030 to 2050)

5b. Sensitivity of land suitable for cereal production to climate change

6a. 400 Years of Sunspot Observations

6b. Smoothed mean excess Annual Rainfall in the three Northern Hemisphere

Zones compared with the corresponding Normalized Annual Sunspot Numbers

Climate Change: Myths & Realities v Dr. S Jeevananda Reddy

6c. Difference between the actual and normal annual rainfalls at two Latitudes in

Australia in Southern Hemisphere

6d. Smoothed Annual Rainfall Totals at Fortaleza in Southern Hemisphere and

Annual Sunspot Numbers

6e. Smoothed Annual Rainfall Totals at three places in South Africa in Southern

Hemisphere and Annual Sunspot Numbers

6f. Ten-Year smoothed means of the Annual Rainfall quartile for Adelaide in Australia

and Normalized Sunspot Numbers

6g. Smoothed means of the July central-England temperatures compared with

the conventional double Sunspot Cycle

6h. Five-year means of the Annual lighting incidence Index compared with Sunspot

Numbers

6i. Smoothed variations in Magnetic Intensity at Eskdalemuir and Stonyhurst in

Great Britain with central-England winter Temperatures and Annual Rainfall

for England and Wales

6j. Magnetic Intensity and information about the Temperature obtained from a

single deep-sea core

6k. Reconstructed Past Temperature Time Series

6l. Standardized time series of rainfall anomalies for the twentieth century (top)

and a century period of the GFDL model simulation containing the most

prominent dry episodes (bottom)

6m. Annual march of dates of onset of Southwest Monsoon over Kerala Coast in

India along with 10-year moving average

6n. Observed and predicted seasonal trend in annual rainfall data of Fortaleza in

Brazil

6o. Observed and predicted seasonal trend in annual rainfall data of Mahalapye in

Botswana, Southern Africa

6p. Annual march of observed & predicted annual rainfall of Catuane in Mozambique,

southern Africa

6q. Seasonal pattern of annual rainfall at few selected locations in Ethiopia, northern

Africa: (a) Gore, (b) Jijiga, (c) Asmara, and (d) Mayole

6r. Observed and predicted seasonal trend in annual rainfall of Durban/Louis Botha

in South Africa

6s. Annual march of observed and predicted Southwest Monsoon season rainfall

of India

6t. Annual march of observed and predicted Southwest & Northeast Monsoon

rainfall of three meteorological sub-divisions of Andhra Pradesh in India

7a. Urban land use change for Chicago-Milwaukee during 1955-1995

7b. Urban change in the Williamette Valley region over 115 years (1880-1995)

Climate Change: Myths & Realities vi Dr. S Jeevananda Reddy

7c. Urban growth in and around Washington, D.C. over 200 years (1880 – 1990)

with a projection for 2025

7d. Changes in urban, agriculture, and forested lands in the Patuxent River

Watershed over 140 years (1850 – 1992)

7e. A City makes its own Weather – Vertical section

7f. Summer, in the city – downtown Sacramento

7g. Hot time in Sacramento in 1998

7h. Islands of urban warmth – urban to rural section

7i. Rate of heat island growth in 11 cities in USA

7j. Impact of orography changes on Rainfall of Santacruz in Mumbai

7k. Impact of cool-island on rainfall in the three meteorological Sub-divisions of

AP during SWM & NEM

8a. Projections of Global Warming under different model forms

8b. Atmospheric Carbon Dioxide increase in the past 200 years

8c. Monthly mean carbon dioxide concentrations

8d. Total global level fossil fuel consumption

8e. Number of stations measuring GHGs elements

8f. Global & Hemispherical Average Temperature Patterns during 1850-2006

8g. Global Average Temperature series as measured by Satellites & upper air

Balloons

9a. Hydrological Cycle

9b. Five-year Running mean of Atlantic Basin Hurricanes during 1851- 2006

9c. Cyclones per year during 1945-2000 (May to November) in Bay of Bengal

Region as presented by Joint Typhoon Warning Centre

9d. Global Five-year and Annual Average Temperature Patterns

Climate Change: Myths & Realities vii Dr. S Jeevananda Reddy

Preface

The “Science of Climate Change” has turned into a political satire of “Global

Warming & Carbon Credits”. In tune with this the “Science of Climate Change”

moved from a scientific body, the World Meteorological Organization (WMO), into

an elected political body, the Intergovernmental Panel on Climate Change (IPCC)

and as a result the scientific community and the media along with political

communities started thinking locally and acting globally. In this process the major

casualty is the health of life forms on the Earth, more particularly in developing

countries, most of which are located in “warm” tropics.

The literature is flooded with statements such as: Eleven of the world’s most

respected national science academies, including the U.S. National Academy of

Sciences, issued a joint statement in anticipation of the 2005 G8 Summit: “Climate

Change is real. There will always be uncertainty in understanding a system as

complex as the world’s climate. However, there is now strong evidence that significant

Global Warming is occurring”. The statement called on world leaders to acknowledge,

“The threat of Climate Change is clear and increasing”, and urged all nations “to

take prompt action to reduce the causes of Climate Change”.

The new study Commissioned by the UN Office for the Coordination of

Humanitarian Affairs and the non-governmental organization CARE International

identified India, Pakistan, Afghanistan and Indonesia as being among Global

Warming “hotspots” or countries particularly vulnerable to increases in extreme

drought, flooding and cyclones anticipated in coming 20 to 30 years. (Humanitarian

Implications of Climate Change, August 2008). Al Gore has been actively

campaigning to stir action at various levels to combat the impending climate crisis.

An Inconvenient Truth, a movie on climate change produced by him presents what

he thought, “the scientific evidence on the human driven climate change”, which

fetched him the Noble Prize with huge world-wide Public Relation (PR) campaign,

that includes a large contingent from India too.

The unscientific nature of all these statements is seen from IPCC observation,

the fact that “These basic conclusions have been endorsed by at least thirty

Scientific Societies and Academies of Science. While the individual scientists

have voiced disagreement with some findings of the IPCC, the overwhelming majority

of scientists working on climate change agree with IPCC on the main conclusion”.

In this, the basic question to be answered from such pronouncements is: “Should

the science be based on what many accepted/endorsed or should it be based on

what is scientifically valid? Or should it be based on PR campaign” and yet IPCC

received the Noble Prize. This has become the deathbed to the “Science of Climate

Change”.

The fact is that both the ozone “creation & destruction” and “cooling &

warming” of global temperatures are in built in nature. There is an absolute one-to-

one relation in ozone depletion theory and thus, though in the initial stages there

was a stiff opposition from industry, it became easy to replace ozone depleting

Climate Change: Myths & Realities viii Dr. S Jeevananda Reddy

substances by non-ozone depleting substances. The reversing trend in ozone

depletion is already evident. Unfortunately, there is no such one-to-one relation in

global warming theory, as there are several process involved. The issue is not

moving in the right direction, as political interests are inter-woven in the issue of

global warming, that is leading no where. Therefore, there is an urgent need to

take a re-look into the “Science of Climate Change” and scientists at individual

level and organization level must go back to the studies made in the field of

climate change prior to 1980s. It is more important in the developing countries

wherein a majority of people depends on agriculture in which climate is the

backbone of agriculture. The present book looks in this angle of climate change

perspective. Though this may need both physical & mental action unlike in the

modeling activity, it is a worthwhile exercise.

It is not the objective of the book to say “control of greenhouse gases is not

an important issue in relation to global temperature rise which has political

ramifications” but on the contrary it’s objective is to “highlight the importance of

controlling the greenhouse gases/pollution in relation to their direct impacts on

the life forms which have human ramifications at local level” – think globally but

act locally. Therefore, the main objective of this book is to bring to the notice of

rulers of the day, the importance of systematic changes in climate that are beyond

human control & other changes in climate due to human interference that have

significant effect on agriculture and life forms on the Earth. One of the main

components of human interference is ecological change such as land use/land

cover changes. Ecological changes not only influence the radiation balance but

also the greenhouse gases balance in the atmosphere. These will automatically

contribute to global control processes, either directly or indirectly.

It is difficult to change the western-mind set of people, unless they come out

from that web and try to understand the others point of view that really benefit

the developing nations like India. Hypocrisy thy name!!! They are more interested

in public relation propaganda to fetch awards-rewards to western vested masters,

who are the agents of multinational companies. These PR propaganda groups talk

against thermal power industry & Hydroelectricity through big dams but failed to

talk of industries that are involved in green revolution technology; & biotechnology,

which are in the hands of multinational companies, or industries that manufacture

the drugs to treat the new diseases created by the green revolution technology,

which in turn create more new diseases; as well the biotechnology that causes the

destruction of plant species in developing countries.

The author used some of the text & figures from Internet & other sources of

several scientists. I herewith acknowledge all those scientists with great respect.

Hyderabad Dr. S. Jeevananda Reddy

4th November 2008

Climate Change: Myths & Realities 1 Dr. S Jeevananda Reddy

Chapter 1

Earth’s Atmosphere

1.1 Natural Composition of Atmosphere

The Earth’s Atmosphere is a layer of gases and retained by gravity. It contains

around 78.0842% of nitrogen, 20.9463% of oxygen, 0.9342% of organ, 0.0381%

of carbon dioxide, 0.002% of other gases and around 1 to 4% of water vapour.

This mixture of gases is commonly known as air. This regulates the Sun’s energy

reaching the Earth’s surface. There is no definite boundary between the atmosphere

and outer space. It slowly becomes thinner and fades into space. Three quarters of

the atmosphere’s mass is within around 11 km from the Earth’s surface. However,

the composition of the atmosphere varies, depending up on the location, the

weather, and many other factors. There may be more water in the air after a

rainstorm, or near the Ocean. Volcanoes can put large amounts of dust particles

high into the atmosphere. Pollution can add different gases or dust and soot.

1.2 Atmospheric Layers

The temperature presents a peculiar behaviour as we go up from the Earth’s

surface into space. Based on the system of variations in temperature with altitude,

the Earth’s Atmosphere is divided into five layers [Figure 1a]. It is thickest near the

surface and thins out with the height until it eventually merges with the space.

1.2.1 Troposphere

Troposphere is the lowest layer of the atmosphere. It begins at the Earth’s

surface and extends to around 17 km at the poles and 21 km at the equator — if

one goes through the internet literature, different articles & figures present different

heights —, with some variations due to weather factors. The troposphere has a

great deal of vertical mixing due to solar heating at the surface. This heating

warms air masses, which makes them less dense so they rise. When an air mass

raises, the pressure upon it decreases so it expands, doing work against the opposing

pressure of the surrounding air. To do work is to expend energy, so the temperature

of the air mass decreases (Figure 1b]. As the temperature decreases, water vapor in

the air mass may condense or solidify, releasing latent heat that further uplifts the

air mass. This process determines the maximum rate of decline of temperature

with height, called the adiabatic lapse rate.

Troposphere contains roughly 80% of the total mass of the atmosphere.

Weather occurs only in this layer because it is this layer that contains most of the

water vapour. Weather is the way water changes in the air, and so without water

there would be no clouds, rain, snow or other weather features. The troposphere is

an unstable layer where the air is constantly moving. As a result, aircraft flying

through the troposphere may have a very bumpy ride – what we know as turbulence.

Because of this turbulence, most jet airlines fly above troposphere, where the air is

more still and clear as they can fly above the Clouds.


Tropopause: It is a boundary in the atmosphere between the troposphere and the

next layer, known as stratosphere [Figure 1c]. Here the air ceases to cool at around

–50 °C (-58 °F), and the air becomes almost completely dry. It is at its highest

level over the equator and the lowest over the geographical North Pole and South

Pole. On account of this, the coolest layer in the atmosphere lies at about 21 km

over the equator and around 17 km at poles. Due to the variation in starting

height, the tropopause extremes are referred to as the equatorial tropopause and

the polar tropopause.

Measuring the lapse rate through the troposphere and the stratosphere

identifies the location of the tropopause. In the troposphere, the lapse rate is, on

an average 6.5 °C per km. That is to say, for every km in height, the temperature

decreases by 6.5 °C. The region of the atmosphere where the lapse rate changes

from positive (in the troposphere) to negative (in the stratosphere), i.e., where the

temperature no longer decreases with altitude but rather increases, is defined as

the tropopause. This occurs at the equilibrium level, a value important in atmospheric

thermodynamics.

The literature presents several ways of defining tropopause. They are for example:

• The definition used by the World Meteorological Organization (WMO) is:

the lowest level at which the lapse rate decreases to 2 °C/km or less, provided

that the average lapse rate between this level and all higher levels within 2

km does not exceed 2 °C/km.

• A dynamic definition of the tropopause is used with potential vorticity

instead of vertical temperature gradient as the defining variable. There is no

universally used threshold: the most common ones are: the tropopause lies

at the 2 PVU or 1.5 PVU surface. PVU stands for potential vorticity unit.

This threshold will be taken as a positive or negative value (e.g. 2 and -2

PVU), giving surfaces located in the Northern and Southern Hemisphere

respectively. To define a global tropopause in this way, the two surfaces

arising from the positive and negative thresholds need to be joined near the

equator using another type of surface such as a constant potential

temperature surface.

• It is also possible to define the tropopause in terms of chemical composition.

For example, the lower stratosphere has much higher ozone concentrations

than the upper troposphere, but much lower water vapour concentrations;

so appropriate cutoffs can be used.

The tropopause is not a “hard” boundary. Vigorous thunderstorms, for example,

particularly those of tropical origin, will overshoot into the lower stratosphere and

undergo a brief (hour-order) low-frequency vertical oscillation. Such oscillation

sets up a low-frequency atmospheric gravity wave capable of affecting both the

Atmospheric and the Oceanic currents in the region. Most commercial aircraft are

flown in the tropopause.


Thermal Inversions: In meteorology, in the normal situation, the temperature

decreases as you go up in altitude in the troposphere. An inversion is a deviation

from the normal change of an atmospheric property with altitude. It almost always

refers to a temperature inversion, known as thermal inversion, i.e., an increase in

temperature with height, or to the layer within which such an increase occurs.

There are several reasons why an inversion might develop. One situation in which a

low level, or surface inversion, might take place is on a clear night, when the

earth’s surface radiates heat away rapidly. If the air is clear, the ground, and the

air directly above it, can be cooler than the air at higher altitudes. This type of

situation may occur on winter nights in California, and can be a problem for citrus

growers, because if enough heat radiates away, the temperature at the ground

surface can drop below the freezing level. Another type of inversion, called an

advectional inversion, involves a horizontal inflow of cold air. This might be air

blowing in from cold water to a coastal area. Along the California coast, winds

frequently blow onshore, passing over the cold ocean waters before reaching land.

When this occurs, the air at ground level may be colder than the air above it, and

the air is stable. A third type of surface inversion takes place at night in valleys,

when cold, dense air flows down slope under the influence of gravity, draining off

the slopes and uplands, and into the valleys. The air in the valley bottoms is

colder than the air above.

Other types of inversions may also develop under various conditions. In

California, upper air inversions develop because much of California is on the eastern

edge of the subtropical high-pressure cell in the Pacific Ocean. This high-pressure

cell develops in response to global patterns of atmospheric pressure and circulation,

rather than local conditions. The presence of high pressure means that the air in

the region is subsiding from high altitudes in the atmosphere. The increasing

pressure of the surrounding air compresses the subsiding air as it descends, so the

air warms up as it subsides. So not only is there cool air at ground level (from

onshore flow of cool air), there is also a general subsidence of warm air aloft. The

inversion layer acts as a lid to prevent air at ground level from rising and dispersing.

If there are mountains inland, the mountains can also help trap the air. This

means that any pollutants emitted accumulate in the trapped air. The bottom line

is that conditions in California frequently favor the development of temperature

inversions. The pollutants will continue to become more concentrated until a

change in the weather leads to the breakup of the inversion layer.

The normal decrease in temperature with altitude has lots of implications

for weather. In the context of air pollution, it means that the decrease in temperature

helps to mix the air, and disperse pollutants. If a parcel of air is warmer than the

surrounding air, it is less dense, more buoyant, and it has a tendency to rise up

until it finds air that is about the same temperature and density as it is. This helps

disperse pollutants at the surface. On the other hand, air, which is cold and dense,

is likely to be stable, and stay put. A very stable situation would occur when cold

air is near the ground, and there is a layer of warmer air above it. This cold air is

denser than the warm air above it. It resists rising, and is described as stable


air. Above the inversion layer, the air will again cool off with increasing altitude. In

urban areas, in winter, the inversions occur more frequently than in its’ neighbouring

rural areas. Here heat is released by vehicles and buildings.

An inversion can lead to pollution such as smog being trapped close to the

ground, with possible adverse effects on health. An inversion can also suppress

convection by acting as a “cap”. If this cap is broken for any of several reasons,

convection of any moisture present can then erupt into violent thunderstorm.

Photochemical smog is brown smog, the gray-brown haze that fills the air in

many cities. It is especially a problem in warm, sunny regions where there are lots

of cars burning gasoline. Researchers in the 1940’s and 1950’s in Los Angeles

noticed that the kinds of pollutants in the air varied over the course of the day.

Some pollutants increased in the morning, as people started driving their cars.

Other pollutants, including the visible, brown smoggy haze, were most common in

the middle of the day. The mix of pollutants changed again in the late afternoon

and evening. It became apparent that the chemical reactions among the various

pollutants were related to sunlight. Smog is worse in Los Angeles—and everywhere—

in the summer, because the light energy from the Sun moves some of the reactions

along. To form photochemical smog, three main ingredients are needed: nitrogen

oxides (NOx), hydrocarbons, and energy from the Sun in the form of ultraviolet

light (UV). The first thing that starts the chain of events is that people start

driving in the morning. As gasoline is burned, nitrogen (N2) in the atmosphere is

also burned, or oxidized, forming nitric oxide (NO): N2 + O

2 = 2NO. Hydrocarbons

and carbon monoxide (CO) will also be emitted by cars. Hydrocarbons are volatile

organic compounds that may include acetaldehyde, formaldehyde, ethylene, and

many other compounds. In the air, nitric oxide combines with molecular oxygen to

form nitrogen dioxide within a few hours as: 2NO + O2 --->2NO

2. Nitrogen

dioxide absorbs light energy and splits to form nitric oxide and atomic oxygen:

NO2--->NO + O. Then, in sunlight, the atomic oxygen combines with oxygen gas

to form ozone (O3): O+ O

2--->O

3. If no other factors are involved, ozone and

nitric oxide then react to form nitrogen dioxide and oxygen gas as:

O3 + NO<------>NO

2 + O

2. This last reaction can go in either direction, depending

on temperature and the amount of sunlight. If there is a lot of sunlight, the

equation moves to the left, and more ozone is produced. If nothing else gets in

the way, equilibrium is reached, and the ozone level stabilizes. However, there is

something else involved. Remember that the cars are also emitting hydrocarbons

as well as oxides of nitrogen. Hydrocarbons are the other main ingredient in

photochemical smog. When hydrocarbons are present, nitric oxide reacts with

them instead of the ozone. This reaction produces a variety of toxic products,

such as a volatile compound known as PAN (peroxyacetyl nitrate):

NO + hydrocarbons ----->PAN and various other compounds. Also,

NO2

+hydrocarbons ----->PAN and various other compounds

So, there are two results (at least) from the reaction of nitrogen oxides with

hydrocarbons. One is that a lot of volatile, reactive organic compounds are generated


directly. The other is that when the nitric oxide (NO) is busy reacting with

hydrocarbons, it is not reacting with ozone to break it back down to molecular

oxygen. So the amount of ozone in the air increases. With nitric oxide reacting

with hydrocarbons, ozone may accumulate to damaging levels. (Ozone may also be

released into the air naturally by forest fires. But in a natural situation, ozone

would react with nitric oxide and be broken down to oxygen, as noted above). The

result, then, is an accumulation of ozone and volatile organic compounds such as

PAN. These are referred to as secondary pollutants, because they are formed by

the reaction of primary pollutants, nitrogen oxides and hydrocarbons, emitted by

burning fossil fuels. The energy from the sun moves the reactions along. This

forms photochemical smog, the brown gunk we see in the sky, especially on hot

sunny days. Photochemical smog can cause eye irritation and poor visibility. Strong

oxidants such as ozone can damage the lungs. The oxidants irritate the linings of

lungs. Damage to the lungs may stress the heart. Health damage is worse for

people with existing lung and heart conditions. Other health implications may

include loss of immune system function, increased susceptibility to infections,

and fatigue. The damage can be caused by exposure to large amounts of the

pollutant over a short time span, and also by chronic exposure to small amounts

over long periods of time. Oxidants can kill plant cells, causing leaves to develop

brown spots or drop off the plant, reduce plant growth, and make plants more

susceptible to damage from other causes. Oxidants such as ozone can also corrode

and destroy many materials such as rubber, nylon, fabric, and paint. This is a

simplified discussion of photochemical smog formation. There are more reactions

involved, and a number of loops and sub-loops in the sequence of reactions.

1.2.2 Stratosphere

The stratosphere is the second layer of air above the Earth’s surface and

extends to a height of 50 km from the tropopause (Figure 1c). The temperature

increases with the height (Figure 1b). The stratosphere contains the ozone layer,

which contains relatively high concentrations of ozone. It is mainly located in the

lower stratosphere, though the thickness varies seasonally and latitudinally. The

ozone layer absorbs much of the Sun’s harmful radiation that would otherwise be

dangerous to plant and animal life. It is a stable layer and because of this jet

aircrafts generally fly in the stratosphere.

1.2.3 Mesosphere

Beyond the stratosphere the air is very thin and cold. This area is known as

the mesosphere, and is found between 50 km and 80-85 km above the Earth’s

surface, wherein the temperature decreases with the height (Figure 1b). This is the

layer in which meteors burn up when entering the atmosphere.

1.2.4 Thermosphere

The thermosphere is the last layer in the atmosphere. It is located above 80-

85 km wherein the temperature increases with height (Figure 1b). Space shuttles

fly in this area and it is also where the aurora lights are found. Auroras are wispy


curtains of light caused when the Sun strikes gases in the atmosphere above the

Poles. Thermosphere consists of Ionosphere and exosphere [Figure 1a].

Ionosphere is a part of the atmosphere that is ionized by solar radiation. It plays an

important role in atmospheric electricity and forms the inner edge of the

magnetosphere. It has practical importance because, among other functions, it

influences radio propagation to distant places on the Earth.

Exosphere is the upper limit of our atmosphere. It starts from a height of about

500 km and extends around 1000 km. The atmosphere merges into space in the

extremely thin exosphere. Satellites are stationed in this area.

1.3 Atmospheric pressure

Atmospheric pressure is a direct result of the total weight of the air above

the point at which the pressure is measured. This means that air pressure varies

with the location and the time, because the amount (and weight) of air above the

Earth varies with the location and the time. The average atmospheric pressure at

sea level is about 1013.2 mb and the total atmospheric mass is 5.1361 x 1018 kg.

Atmospheric pressure decreases with height, dropping by 50% at around an

altitude of about 5.6 km (18,000 ft). Equivalently, about 50% of the total

atmospheric mass is within the lowest 5.6 km. This pressure drop is approximately

exponential, so that pressure decreases by approximately half every 5.6 km. The

temperature changes throughout the atmospheric column as well as the force of

gravity begin to decrease at great altitudes.

50% of the atmosphere by mass is below around an altitude of 5.6 km;

90% of the atmosphere by mass is below around an altitude of 16 km;

99.99997% of the atmosphere by mass is below around 100 km.

Therefore, most of the atmosphere (99.9997%) is below 100 km, although

in the rarefied region above this there are auroras and other atmospheric effects.

1.4 The Sky Looks Blue!!!

Visible light is the part of the electromagnetic spectrum that our eyes can

see. Light from the Sun or a light bulb may look white, but it is actually a combination

of many colors. We can see the different colors of the spectrum by splitting the

light with a prism. The spectrum is also visible when you see a rainbow in the sky.

The colors blend continuously into one another. At one end of the spectrum are

the reds and oranges. These gradually shade into yellow, green, blue, indigo and

violet. The colors have different wavelengths, frequencies, and energies.


Table 1: Sky Colours vs wavelengths

Colour Wavelength Typical

Interval wavelength

(mm) (mm)

Violet 0.390-0.455 0.430

Dark blue 0.455-0.485 0.470

Light blue 0.485-0.505 0.495

Green 0.505-0.550 0.530

Yellow-green 0.550-0.575 0.560

Yellow 0.575-0.585 0.580

Orange 0.585-0.620 0.600

Red 0.620-0.760 0.640

Violet has the shortest wavelength in the visible spectrum. That means it

has the highest frequency and energy. Red has the longest wavelength, and lowest

frequency and energy. Light travels through space in a straight line as long as

nothing disturbs it. As light moves through the atmosphere, it continues to go

straight until it bumps into a bit of dust or a gas molecule. Then what happens to

the light depends on its wavelength and the size of the thing it hits. Dust particles

and water droplets are much larger than the wavelength of visible light. When

light hits these large particles, it gets reflected, or bounced off, in different

directions. The different colors of light are all reflected by the particle in the same

way. The reflected light appears white because it still contains all of the same

colors. Gas molecules are smaller than the wavelength of visible light. If light

bumps into them, it acts differently. When light hits a gas molecule, some of it

may get absorbed. After awhile, the molecule radiates (releases, or gives off) the

light in a different direction. The color that is radiated is the same color that was

absorbed. The different colors of light are affected differently. All of the colors

can be absorbed. But the higher frequencies (blues) are absorbed more often than

the lower frequencies (reds). This process is called Raleigh scattering — It is

named after Lord John Raleigh, an English physicist, who first described it in the

1870’s.

The blue color of the sky is due to Raleigh scattering. As light moves

through the atmosphere, most of the longer wavelengths pass straight through.

The air affects little of the red, orange and yellow light. However, the gas molecules

absorb much of the shorter wavelength light. The absorbed blue light is then

radiated in different directions. It gets scattered all around the sky. Whichever

direction you look, some of this scattered blue light reaches you. Since you see

the blue light from everywhere overhead, the sky looks blue. As you look closer to

the horizon, the sky appears much paler in color. To reach you, the scattered blue

light must pass through more air. Some of it gets scattered away again in other

directions. Less blue light reaches your eyes. The color of the sky near the horizon

appears paler or white.

On the Earth, the Sun appears yellow. If you were out in space, or on the


Moon, the Sun would look white. In space, there is no atmosphere to scatter the

Sun’s light. On the Earth, some of the shorter wavelength light (the blues and

violets) is removed from the direct rays of the Sun by scattering. The remaining

colors together appear yellow. Also, out in space, the sky looks dark and black,

instead of blue. This is because there is no atmosphere. There is no scattered light

to reach your eyes.

As the Sun begins to set, the light must travel farther through the atmosphere

before it gets to you. More of the light is reflected and scattered. As less reaches

you directly, the Sun appears less bright. The color of the Sun itself appears to

change, first to orange and then to red. This is because even more of the short

wavelength blues and greens are now scattered. Only the longer wavelengths are

left in the direct beam that reaches your eyes.

The sky around the setting the Sun may take on many colors. The most

spectacular shows occur when the air contains many small particles of dust or

water. These particles reflect light in all directions. Then, as some of the light

heads towards you, different amounts of the shorter wavelength colors are scattered

out. You see the longer wavelengths, and the sky appears red, pink or orange.

1.5 Effect of Human Interference!!!

1.5.1 Air Pollution

Atmospheric pollution, also commonly called air pollution, is derived chiefly

from the spewing of gasses and solid particulates into the atmosphere. Many

pollutants such as dust, pollen, and soil particles occur naturally, but most air

pollution, as the term is most commonly used and understood, is caused by human

activity. Although there are countless sources of air pollution, the most common

are emissions from the burning of hydrocarbons or fossil fuels e.g., coal and oil

products. Most of the world’s industrialized countries rely on the burning of fossil

fuels; power plants, heat homes and provide electricity, automobiles burn gas, and

factories burn materials to create products.

Air pollution is a serious global problem, and is especially problematic in

large urban areas all over the world. Many people suffer from serious illnesses

caused by smog and air pollution in these areas. Plants, buildings, and animals are

also victims of a particular type of air pollution called acid rain. Acid rain is caused

by airborne sulfur from burning coal in power plants and can be transported in rain

droplets for thousands of miles. Poisons are then deposited in streams, lakes, and

soils, causing damage to wildlife. In addition, acid rain eats into concrete and

other solid structures, causing buildings to slowly deteriorate.

Scientists study air pollution by breaking the particulates into two different

categories of gasses: permanent and variable. The most common of the stable

gasses are nitrogen at 78%, and oxygen at 21% of the total atmosphere. Other

highly variable gasses are water vapor, carbon dioxide, methane, carbon monoxide,

sulfur dioxide, nitrogen dioxide, ozone, ammonia, and hydrogen sulfide.


Output of variable gasses increases with the growth of industrialization and

population & their life style. The benefits of progress cost people billions of dollars

each year in repairing and preventing air pollution damage. This includes health

care and the increased maintenance of structures that are crumbling, in part due

to air pollution.

The effects of air pollution have to be carefully measured because the build-

up of particulates depends on atmospheric conditions and a specific area’s emission

level. Once pollutants are released into the atmosphere, wind patterns make it

impossible to contain them to any particular region. On the other hand, terrestrial

formations such as mountain ridges can act as natural barriers. The terrain and

climate of a particular area can also help promote or deflect air pollution. Specifically,

weather conditions called thermal inversions can trap the impurities and cause

them to build up until they have reached dangerous levels. A thermal inversion is

created when a layer of warm air settles over a layer of cool area closer to the

ground. It can stay until rain or wind dissipates the layer of stationary warm air. In

addition to atmospheric pollution, indoor air pollution also poses special hazards.

Some man-made sources of indoor air pollutants include asbestos particulates and

formaldehyde vapors — once common building materials now thought to cause

cancer. Lead paint is also a problem in older buildings, but its use has been phased

out. Other sources of man-made indoor air pollution include improperly vented

stoves and heaters, tobacco smoke, and emissions or spillage from pesticides,

aerosol sprays, solvents, and disinfectants.

1.5.2 Types & Sources

Air Pollution is the human introduction into the atmosphere of chemicals,

particulates, or biological materials that cause harm or discomfort to humans or

other living organisms, or damage the environment. Air pollution causes deaths

and respiratory diseases Air pollution is often identified with major stationary

sources. The atmosphere is a complex, dynamic natural gaseous system that is

essential to support life on the planet Earth. Stratosphere ozone depletion due to

air pollution has long been recognized as a threat to human health as well as to

the Earth’s ecosystems. There are many substances in the air, which may impair

the health of plants and animals including humans, or reduce visibility.

These arise both from natural processes and human activity. Substances

not naturally found in the air or at greater concentrations or in different locations

from usual are referred to as pollutants.

Pollutants can be classified as either primary or secondary. Primary pollutants are

substances directly emitted from a process, such as ash from a volcanic eruption

or the carbon monoxide gas from a motor vehicle exhaust. Secondary pollutants

are not emitted directly. Rather, they form in the air when primary pollutants react

or interact. An important example of a secondary pollutant is ground level ozone -

one of the many secondary pollutants that make up photochemical smog. Note

that some pollutants may be both primary and secondary: that is, they are both

emitted directly and formed from other primary pollutants.


Major primary pollutants produced by human activity include: (i) Sulfur oxides

(SOx) especially sulfur dioxide are emitted from burning of coal and oil; (ii) Nitrogen

oxides (NOx) especially nitrogen dioxide are emitted from high temperature

combustion. Can be seen as the brown haze dome above or plume downwind of

cities; (iii) Carbon monoxide is colourless, odourless, non-irritating but very poisonous

gas. It is a product by incomplete combustion of fuel such as natural gas, coal or

wood. Vehicular exhaust is a major source of carbon monoxide; (iv) Carbon dioxide

(CO2), a greenhouse gas emitted from combustion; (v) Volatile organic compounds

(VOC), such as hydrocarbons, fuel vapors and solvents; (vi) Particulate matter

(PM), measured as smoke and dust. PM10

is the fraction of suspended particles 10

micrometers in diameter and smaller that will enter the nasal cavity. PM2.5

has a

maximum particle size of 2.5 μm and will enter the bronchitis and lungs; (vii) Toxic

metals, such as lead, cadmium and copper; (viii) Chloral-fluorocarbons (CFCs),

harmful to the ozone layer emitted from products currently banned from use; (ix)

Ammonia (NH3) emitted from agricultural processes; (x) Odors, such as from garbage,

sewage, and industrial processes; (xi) Radioactive pollutants produced by nuclear

explosions and was explosives, and natural processes such as radon.

Secondary pollutants include: (i) Particulate matter formed from gaseous primary

pollutants and compounds in photochemical smog, such as nitrogen dioxide; (ii)

Ground level ozone (O3) formed from NO

x and VOCs; (iii) Peroxyacetyl nitrate

(PAN) similarly formed from NOx and VOCs.

Minor air pollutants: A large number of minor hazardous air pollutants are also

released into atmosphere. Some of these are regulated in USA under the Clean Air

Act and in Europe under the Air Framework Directive. A variety of persistent organic

pollutants can be attached to particulate matter.

Sources of air pollution refer to the various locations, activities or factors, which

are responsible for the releasing of pollutants in the atmosphere [Annexure I].

These sources can be classified into two major categories, which are:

(a) Anthropogenic sources (human activity) mostly related to (i) burning different

kinds of fuel; (ii) “Stationary Sources” as smoke stacks of power plants,

manufacturing facilities, municipal waste incinerators; (iii) “Mobile Sources” as

motor vehicles, aircraft etc.; (iv) Marine vessels, such as container ships or cruise

ships, and related port air pollution; (v) Burning wood, fireplaces, stoves, furnaces

and incinerators; (vi) Oil refining, and industrial activity in general; (vii) Chemicals,

dust and controlled burn practices in agriculture and forestry management; (viii)

Fumes from paint, hair spray, varnish, aerosol sprays and other solvents; (ix) Waste

deposition in landfills, which generate methane; (x) Military, such as nuclear weapons,

toxic gases, germ warfare and rocketry.

(b) Natural sources: Dust from natural sources, usually large areas of land with

little or no vegetation. Methane, emitted by the digestion of food by animals, for

example cattle; Radon gas from radioactive decay within the Earth’s crust; Smoke

and carbon monoxide from wildfires; Volcanic activity, which produce sulfur, chlorine,

and ash particulates, etc.


Most Polluted Cities: Air pollution is usually concentrated in densely populated

metropolitan areas, especially in developing countries where environmental

regulations are generally relatively lax. However, even populated areas in developed

countries attain unhealthy levels of pollution. Table 2 presents most polluted cities

by particulate matter in 2004.

Table 2: Most Polluted Cities by PM in 2004

City Particulate Matter

(mg/m3)

Cairo, Egypt 169

Delhi, India 150

Kolkata, India 128

Tianjin, China 125

Chongqing, China 123

Kanpur, India 109

Lucknow, India 109

Jakarta, Indonesia 104

Shenyang, China 101

Annexure I: Major Air Pollutants

Pollutant

Ozone. A gas that can be found

in two places. Near the ground

(the troposphere), it is a major part

of smog. The harmful ozone in the

lower atmosphere should not be

confused with the protective layer

of ozone in the upper atmosphere

(stratosphere), which screens out

harmful ultraviolet rays.

Carbon monoxide. A gas that

comes from the burning of fossil

fuels, mostly in cars. It cannot be

seen or smelled.

Nitrogen dioxide. A reddish-

brown gas that comes from the

Sources

Ozone is not created directly, but

is formed when nitrogen oxides

and volatile organic compounds

mix in sunlight. That is why ozone

is mostly found in the summer.

Nitrogen oxides come from

burning gasoline, coal, or other

fossil fuels. There are many types

of volatile organic compounds,

and they come from sources

ranging from factories to trees.

Carbon monoxide is released

when engines burn fossil fuels.

Emissions are higher when engines

are not tuned properly, and when

fuel is not completely burned.

Cars emit a lot of the carbon

monoxide found outdoors.

Furnaces and heaters in the home

can emit high concentrations of

carbon monoxide, too, if they are

not properly maintained.

Nitrogen dioxide mostly comes

from power plants and cars.

Effects

Ozone near the ground can cause

a number of health problems.

Ozone can lead to more frequent

asthma attacks in people who have

asthma and can cause sore

throats, coughs, and breathing

difficulty. It may even lead to

premature death. Ozone can also

hurt plants and crops.

Carbon monoxide makes it hard

for body parts to get the oxygen

they need to run correctly.

Exposure to carbon monoxide

makes people feel dizzy and tired

and gives them headaches. In high

concentrations it is fatal. Elderly

people with heart disease are

hospitalized more often when they

are exposed to higher amounts of

carbon monoxide.

High levels of nitrogen dioxide

exposure can give people coughs


burning of fossil fuels. It has a

strong smell at high levels.

Particulate matter. Solid or liquid

matter that is suspended in the air.

To remain in the air, particles

usually must be less than 0.1-mm

wide and can be as small as

0.00005 mm.

Sulfur dioxide. A corrosive gas

that cannot be seen or smelled at

low levels but can have a “rotten

egg” smell at high levels.

Lead. A blue-gray metal that is

very toxic and is found in a

number of forms and locations.

Toxic air pollutants. A large

number of chemicals that are

known or suspected to cause

cancer. Some important pollutants

in this category include arsenic,

asbestos, benzene, and dioxin.

Stratospheric ozone depleters.

Chemicals that can destroy the

ozone in the stratosphere. These

Nitrogen dioxide is formed in two

ways—when nitrogen in the fuel

is burned, or when nitrogen in the

air reacts with oxygen at very high

temperatures. Nitrogen dioxide

can also react in the atmosphere

to form ozone, acid rain, and

particles.

Particulate matter can be divided

into two types—coarse particles

and fine particles. Coarse particles

are formed from sources like road

dust, sea spray, and construction.

Fine particles are formed when fuel

is burned in automobiles and

power plants.

Sulfur dioxide mostly comes from

the burning of coal or oil in power

plants. It also comes from factories

that make chemicals, paper, or

fuel. Like nitrogen dioxide, sulfur

dioxide reacts in the atmosphere

to form acid rain and particles.

Outside, lead comes from cars in

areas where unleaded gasoline is

not used. Lead can also come from

power plants and other industrial

sources. Inside, lead paint is an

important source of lead,

especially in houses where paint

is peeling. Lead in old pipes can

also be a source of lead in drinking

water.

Each toxic air pollutant comes

from a slightly different source, but

many are created in chemical plants

or are emitted when fossil fuels

are burned. Some toxic air

pollutants, like asbestos and

formaldehyde, can be found in

building materials and can lead to

indoor air problems. Many toxic

air pollutants can also enter the

food and water supplies.

CFCs are used in air conditioners

and refrigerators, since they work

well as coolants. They can also

and can make them feel short of

breath. People who are exposed

to nitrogen dioxide for a long time

have a higher chance of getting

respiratory infections. Nitrogen

dioxide reacts in the atmosphere

to form acid rain, which can harm

plants and animals.

Particulate matter that is small

enough can enter the lungs and

cause health problems. Some of

these problems include more

frequent asthma attacks,

respiratory problems, and

premature death.

Sulfur dioxide exposure can affect

people who have asthma or

emphysema by making it more

difficult for them to breathe. It can

also irritate people’s eyes, noses,

and throats. Sulfur dioxide can

harm trees and crops, damage

buildings, and make it harder for

people to see long distances.

High amounts of lead can be

dangerous for small children and

can lead to lower IQs and kidney

problems. For adults, exposure to

lead can increase the chance of

having heart attacks or strokes.

Toxic air pollutants can cause

cancer. Some toxic air pollutants

can also cause birth defects. Other

effects depend on the pollutant,

but can include skin and eye

irritation and breathing problems.

If the ozone in the stratosphere is

destroyed, people are exposed to

more radiation from the sun


chemicals include

chlorofluorocarbons (CFCs),

halons, and other compounds

that include chlorine or bromine.

Greenhouse gases. Gases that

stay in the air for a long time and

warm up the planet by trapping

sunlight. This is called the

“greenhouse effect” because the

gases act like the glass in a

greenhouse. Some of the

important greenhouse gases are

carbon dioxide, methane, and

nitrous oxide.

be found in aerosol cans and fire

extinguishers. Other stratospheric

ozone depleters are used as

solvents in industry.

Carbon dioxide is the most

important greenhouse gas. It

comes from the burning of fossil

fuels in cars, power plants,

houses, and industry. Methane is

released during the processing of

fossil fuels, and also comes from

natural sources like cows and rice

paddies. Nitrous oxide comes from

industrial sources and decaying

plants.

(ultraviolet radiation). This can

lead to skin cancer and eye

problems. Higher ultraviolet

radiation can also harm plants and

animals.

The greenhouse effect can lead to

changes in the climate of the

planet. Some of these changes

might include more temperature

extremes, higher sea levels;

changes in forest composition,

and damage to land near the coast.

Human health might be affected

by diseases that are related to

temperature or by damage to land

and water.

Source: Jonathan Levy, Harvard School of Public Health. Based on information

provided by the Environmental Protection Agency.


Chapter 2

Ozone Depletion

2.1 What is Ozone?

Ozone is a form of oxygen. Oxygen occurs in three different forms in the

atmosphere, namely as atoms (O), as molecules (O2) and as ozone (O3). Ozone’s

unique physical properties allow the ozone layer to act as our planet’s sunscreen,

providing an invisible filter to help protect all life forms from the Sun’s damaging

UV (ultraviolet) rays. Most incoming UV radiation is absorbed by ozone and prevented

from reaching the Earth’s surface. Without the protective effect of ozone, life on

the Earth would not have evolved the way it has.

The Sun emits a range of energy known as the electromagnetic spectrum

[Figure 2a]. The various forms of energy, or radiation, are classified according to

wavelength (measured in nanometers where one nm is a millionth of a millimeter).

The shorter the wavelength, the more energetic is the radiation. In order of

decreasing energy, the principal forms of radiation are gamma rays, x-rays, UV

(ultraviolet radiation), visible light, infrared radiation, microwaves, and radio waves.

Ultraviolet, which is invisible, is so named because it occurs next to violet in the

visible light spectrum. UV radiation is divided into three categories as: UV-A between

320 and 400 nm; UV-B between 280 and 320 nm; UV-C between 200 and 280 nm.

Of these UV-B and C being highly energetic and are dangerous to life on the Earth.

UV-A being less energetic is not dangerous. Fortunately, UV-C is absorbed strongly

by oxygen and also by ozone in the upper atmosphere. UV-B is also absorbed by

ozone layer in the Stratosphere and only 2-3% of it reaches the Earth’s surface.

The ozone Layer, therefore, is highly beneficial to plant and animal life on the

Earth in filtering out the dangerous part of the Sun’s radiation and allowing only

the beneficial part to reach the Earth. Any disturbance or depletion of this layer

would result in an increase UV-B and UV-C radiation reaching the Earth’s surface

leading to dangerous consequences.

2.2 History of Ozone Research

Sydney Chapman discovered the basic physical and chemical processes that

lead to the formation of an ozone layer in the Earth’s stratosphere in 1930. These

are discussed in the article Ozone-oxygen cycle — briefly, short-wavelength UV

radiation splits an oxygen (O2) molecule into two oxygen (O) atoms, which then

combine with other oxygen molecules to form ozone. Ozone is removed when an

oxygen atom and an ozone molecule “recombine” to form two oxygen molecules,

i.e. O + O3 = 2O

2.

In the 1950s, David Bates and Marcel Nicolet presented evidence that various

free radicals, in particular hydroxyl (OH) and nitric oxide (NO), could catalyze this

recombination reaction, reducing the overall amount of ozone. These free radicals

were known to be present in the stratosphere, and so were regarded as part of the


natural balance – it was estimated that in their absence, the ozone layer would be

about twice as thick as it currently is.

In 1970 Prof. Paul Crutzen pointed out that emissions of nitrous oxide

(N2O), a stable, long-lived gas produced by soil bacteria, from the Earth’s surface

could affect the amount of nitric oxide (NO) in the stratosphere. Crutzen showed

that nitrous oxide lives long enough to reach the stratosphere, where it is converted

into NO. Crutzen then noted that increasing use of fertilizers might have led to an

increase in nitrous oxide emissions over the natural background, which would in

turn result in an increase in the amount of NO in the stratosphere. Thus human

activity could have an impact on the stratospheric ozone layer. In the following

year, Crutzen and (independently) Harold Johnston suggested that NO emissions

from supersonic aircraft, which fly in the lower stratosphere, could also deplete

the ozone layer.

In 1974 Frank Sherwood Rowland, Chemistry Professor at the University of

California at Irvine, and his postdoctoral associate Mario J. Molina suggested that

long-lived organic halogen compounds, such as CFCs, might behave in a similar

fashion as Crutzen had proposed for nitrous oxide. James Lovelock (most popularly

known as the creator of the Gaia hypothesis] had discovered, during a cruise in the

South Atlantic in 1971, that almost all of the CFC compounds manufactured

since their invention in 1930 were still present in the atmosphere. Molina and

Rowland concluded that, like N2O, the CFCs would reach the stratosphere where

they would be dissociated by UV light, releasing Cl atoms. A year earlier, Richard

Stolarski and Ralph Cicerone at the University of Michigan had shown that Cl is

even more efficient than NO at catalyzing the destruction of ozone. Michael McElroy

and Steven Wofsy at Harvard University reached similar conclusions. Neither group,

however, had realized that CFC’s were a potentially large source of stratospheric

chlorine — instead, they had been investigating the possible effects of HCl emissions

from the Space Shuttle, which are very much smaller.

The Rowland-Molina hypothesis was strongly disputed by representatives

of the aerosol and halocarbon industries. The Chair of the Board of DuPont was

quoted as saying that ozone depletion theory is “a science fiction tale...a load of

rubbish...utter nonsense”. Robert Abplanalp, the President of Precision Valve

Corporation (and inventor of the first practical aerosol spray can valve), wrote to

the Chancellor of UC Irvine to complain about Rowland’s public statements.

Nevertheless, within three years most of the basic assumptions made by Rowland

and Molina were confirmed by laboratory measure-ments and by direct observation

in the stratosphere.

The concentrations of the source gases (CFC’s and related compounds) and

the chlorine reservoir species (HCl and ClONO2) were measured throughout the

strato-sphere, and demonstrated that CFCs were indeed the major source of

stratospheric chlorine, and that nearly all of the CFCs emitted would eventually

reach the stratosphere. Even more convincing was the measurement, by James G.

Anderson and collaborators, of chlorine monoxide (ClO) in the stratosphere. ClO is


produced by the reaction of Cl with ozone — its observation thus demonstrated

that Cl radicals not only were present in the stratosphere but also were actually

involved in destroying ozone. McElroy and Wofsy extended the work of Rowland

and Molina by showing that Bromine atoms were even more effective catalysts for

ozone loss than chlorine atoms and argued that the brominated organic compounds

known as halons, widely used in fire extinguishers, were a potentially large source

of stratospheric bromine.

In 1976 the U.S. National Academy of Sciences released a report, which

concluded that the ozone depletion hypothesis was strongly supported by the

scientific evidence. Scientists calculated that if CFC production continued to increase

at the going rate of 10% per year until 1990 and then remain steady, CFCs would

cause a global ozone loss of 5 to 7% by 1995, and a 30 to 50% loss by 2050. In

response the United States, Canada, Sweden and Norway banned the use of CFCs

in aerosol spray cans in 1978. However, subsequent research, summarized by the

National Academy in reports issued between 1979 and 1984, appeared to show

that the earlier estimates of global ozone loss had been too large.

2.3 Ozone Depletion

Ozone depletion occurs when the natural balance between the production

and destruction of stratospheric ozone is tipped in favour of destruction. Although

natural phenomenon can cause temporary ozone loss, chlorine and bromine released

from synthetic compounds is now accepted as the main cause of a net loss of

stratospheric ozone in many parts of the world since 1980. Ozone is formed in the

stratosphere when oxygen molecules photo-dissociate after absorbing an ultraviolet

photon whose wavelength is shorter than 240 nm. This produces two oxygen

atoms. The atomic oxygen then combines with O2 to create O

3. Ozone molecules

absorb UV light between 310 and 200 nm, following which ozone splits into a

molecule of O2 and an oxygen atom. The oxygen atom then joins up with an

oxygen molecule to regenerate ozone. This is a continuing process which terminates

when an oxygen atom “recombines” with an ozone molecule to make two O2

molecules: O + O3 −−> 2 O

2. A balance between photochemical production and

recombination process determines the overall amount of ozone present in the

stratosphere.

Ozone can be destroyed by a number of free radical catalysts, the most

important of which are the hydroxyl radical (OH), the nitric-oxide radical (NO) and

atomic chlorine (Cl) and bromine (Br). All of these have both natural and

anthropogenic (manmade) sources [Figure 2 b]; at the present time, most of the

OH and NO in the stratosphere is of natural origin, but human activity has

dramatically increased the high in oxygen chlorine and bromine. These elements

are found in certain stable organic compounds, especially chlorofluorocarbons

(CFCs), which may find their way to the stratosphere without being destroyed in

the troposphere due to their low reactivity. Once in the stratosphere, the Cl and Br

atoms are liberated from the parent compounds by the action of ultraviolet light.

The Cl and Br atoms can then destroy ozone molecules through a variety of catalytic


cycles. In the simplest example of such a cycle, a chlorine atom reacts with an

ozone molecule, taking an oxygen atom with it (forming ClO) and leaving a normal

oxygen molecule. A free oxygen atom then takes away the oxygen from the ClO,

and the final result is an oxygen molecule and a chlorine atom, which then reinitiates

the cycle.

The overall effect is to increase the rate of recombination, leading to an

overall decrease in the amount of ozone. For this particular mechanism to operate

there must be a source of O atoms, which is primarily the photo dissociation of

O3; thus this mechanism is only important in the upper stratosphere where such

atoms are abundant. More complicated mechanisms have been discovered that

lead to ozone destruction in the lower stratosphere as well (discussed in previous

chapter). A single chlorine atom would keep on destroying ozone for up to two

years (the time scale for transport back down to the troposphere) were it not for

reactions that remove them from this cycle by forming reservoir species such as

hydrogen chloride (HCl) and chlorine nitrate (ClONO2). On a per atom basis, bromine

is even more efficient than chlorine at destroying ozone, but there is much less

bromine in the atmosphere at present. As a result, both chlorine and bromine

contribute significantly to the overall ozone depletion. Laboratory studies have

shown that fluorine and iodine atoms participate in analogous catalytic cycles.

However, in the Earth’s stratosphere, fluorine atoms react rapidly with water and

methane to form strongly bound hydrofluoric acid, while organic molecules which

contain iodine react so rapidly in the lower atmosphere that they do not reach the

stratosphere in significant quantities. Furthermore, a single chlorine atom is able

to react with 100,000 ozone molecules. This fact plus the amount of chlorine

released into the atmosphere by chlorofluorocarbons (CFCs) yearly demonstrates

how dangerous CFCs are to the environment.

2.4 The Ozone Hole

History: The discovery of the Antarctic “ozone hole” by British Atlantic Survey

scientists Farman, Gardiner and Shanklin (announced in a paper in Nature in May

1985) came as a shock to the scientific community, because the observed decline

in polar ozone was far larger than anyone had anticipated. Satellite measurements

showing massive depletion of ozone around the South Pole were becoming available

at the same time. However, these were initially rejected as unreasonable by data

quality control algorithms (they were filtered out as errors since the values were

unexpectedly low); the ozone hole was detected only in satellite data when the

raw data was reprocessed following evidence of ozone depletion in in situ

observations. When the software was rerun without the flags, the ozone hole was

seen as far back as 1976.

Susan Solomon, an atmospheric chemist at the National Oceanic and

Atmospheric Administration (NOAA), proposed that chemical reactions on Polar

Stratospheric Clouds (PSCs) in the cold Antarctic stratosphere caused a massive,

though localized and seasonal, increase in the amount of chlorine present in active,

ozone-destroying forms. The PSCs in Antarctica are only formed when there are


very low temperatures, as low as -80 oC, and early spring conditions. In such

conditions the ice crystals of the cloud provide a suitable surface for conversion of

non-reactive chlorine compounds into reactive chlorine compounds, which can

deplete ozone easily. Moreover the polar vortex formed over Antarctica is very tight

and the reaction, which occurs on the surface of the cloud crystals, is far different

from when it occurs in atmosphere. These conditions have led to ozone hole

formation in Antarctica. This hypothesis was decisively confirmed, first by laboratory

measurements and subsequently by direct measurements, from the ground and

from high-altitude airplanes, of very high concentrations of chlorine monoxide

(ClO) in the Antarctic stratosphere. Alternative hypotheses, which had attributed

the ozone hole to variations in solar UV radiation or to changes in atmospheric

circulation patterns, were also tested and shown to be untenable. However, the

vortex formation and consequent reduction in temperature is the part of atmospheric

circulation only. This is the region for the differences in ozone depletion at south

and north pole.

Meanwhile, analysis of ozone measurements from the worldwide network of

ground-based Dobson spectrophotometers led an international panel to conclude

that the ozone layer was in fact being depleted, at all latitudes outside of the

tropics. These trends were confirmed by satellite measurements. As a consequence,

the major halocarbon producing nations agreed to phase out production of CFCs,

halons, and related compounds, a process that was completed in 1996. Crutzen,

Molina, and Rowland were awarded the 1995 Nobel Prize in Chemistry for their

work on stratospheric ozone.

When the “ozone hole” forms, essentially all of the ozone in the lower

stratosphere is destroyed. The upper stratosphere is much less affected, however,

so that the overall amount of ozone over the continent declines by 50 percent or

more. The ozone hole does not go all the way through the layer; on the other

hand, it is not a uniform ‘thinning’ of the layer either. It’s a “hole” in the sense of

“a hole in the ground”, a depression, not in the sense of “a hole in the windshield”.

G.M.B. Dobson (Exploring the Atmosphere, 2nd Edition, Oxford, 1968)

mentioned that when springtime ozone levels over Halley Bay were first measured,

he was surprised to find that they were ~320 DU, about 150 DU below spring

levels, ~450 DU, in the Arctic. These, however, were the pre-ozone-hole normal

climatological values. What Dobson describes is essentially the baseline from which

the ozone hole is measured: actual ozone hole values are in the 150–100 DU range.

The discrepancy between the Arctic and Antarctic noted by Dobson was

primarily a matter of timing: during the Arctic spring ozone levels rose smoothly,

peaking in April, whereas in the Antarctic they stayed approximately constant

during early spring, rising abruptly in November when the polar vortex broke down.

The behavior seen in the Antarctic ozone hole is completely different. Instead of

staying constant, early springtime ozone levels suddenly drop from their already

low winter values, by as much as 50%, and normal values are not reached again

until December. If the theory were correct, the ozone hole should be above the


sources of CFCs. The CFCs are well mixed in the troposphere and the stratosphere.

The reason the ozone hole occurs above Antarctica is not because there are more

CFCs there but because the low temperatures allow polar stratospheric clouds to

form. There have been anomalous discoveries of significant, serious, localized “holes”

above other parts of the globe.

It is sometimes stated that since CFC molecules are much heavier than

nitrogen or oxygen, they cannot reach the stratosphere in significant quantities.

But atmospheric gases are not sorted by weight; the forces of wind (turbulence)

are strong enough to fully intermix gases in the atmosphere. CFCs are heavier than

air, but just like argon, krypton and other heavy gases with a long lifetime, they are

uniformly distributed throughout the turbosphere and reach the upper

atmosphere.Since 1981 the UNEP has sponsored a series of reports on scientific

assessment of ozone depletion. The most recent is from 2007 where satellite

measurements have shown the hole in the ozone layer is recovering and is now the

smallest it has been for about a decade.

Ozone Hole Process: The Antarctic ozone hole is an area of the Antarctic

stratosphere in which the recent ozone levels have dropped to as low as 33% of

their pre-1975 values. The ozone hole occurs during the Antarctic spring, from

September to early December, as strong westerly winds start to circulate around

the continent and create an atmospheric container. Within this polar vortex, over

50% of the lower stratospheric ozone is destroyed during the Antarctic spring.

As explained above, the overall cause of ozone depletion is the presence of

chlorine containing source gases (primarily CFCs and related halocarbons). In the

presence of UV light, these gases dissociate, releasing chlorine atoms, which then

go on to catalyze ozone destruction. The Cl catalyzed ozone depletion can take

place in the gas phase, but it is dramatically enhanced in the presence of polar

stratospheric clouds (PSCs). These polar stratospheric clouds form during winter,

in the extreme cold. Polar winters are dark, consisting of 3 months without solar

radiation (sunlight). Not only lack of sunlight contributes to a decrease in

temperature but also the polar vortex traps and chills air. Temperatures hover around

or below -80 °C. These low temperatures form cloud particles and are composed

of either nitric acid (Type I PSC) or ice (Type II PSC). Both types provide surfaces

for chemical reactions that lead to ozone destruction.

The photochemical processes involved are complex but well understood.

The key observation is that, ordinarily, most of the chlorine in the stratosphere

resides in stable “reservoir” compounds, primarily hydrogen chloride (HCl) and

chlorine nitrate (ClONO2). During the Antarctic winter and spring, however, reactions

on the surface of the polar stratospheric cloud particles convert these “reservoir”

compounds into reactive free radicals (Cl and ClO). The clouds can also remove

NO2 from the atmosphere by converting it to nitric acid, which prevents the newly

formed ClO from being converted back into ClONO2.

The role of sunlight in ozone depletion is the reason why the Antarctic ozone

depletion is greatest during spring. During winter, even though PSCs are at their


most abundant, there is no light over the pole to drive the chemical reactions.

During the spring, however, the sun comes out, providing energy to drive

photochemical reactions, and melt the polar stratospheric clouds, releasing the

trapped compounds.

Most of the ozone that is destroyed is in the lower stratosphere, in contrast

to the much smaller ozone depletion through homogeneous gas phase reactions,

which occurs primarily in the upper stratosphere.

Warming temperatures near the end of spring break up the vortex around

mid-December. As warm, ozone-rich air flows in from lower latitudes, the PSCs are

destroyed, the ozone depletion process shuts down, and the ozone hole heals.

While the effect of the Antarctic ozone hole in decreasing the global ozone

is relatively small, estimated at about 4% per decade, the hole has generated a

great deal of interest because the decrease in the ozone layer was predicted in the

early 1980s to be roughly 7% over a sixty-year period. The sudden recognition in

1985 that there was a substantial “hole” was widely reported in the press. The


especially rapid ozone depletion in Antarctica had previously been dismissed as a

measurement error. Many were worried that ozone holes might start to appear over

other areas of the globe but to date the only other large-scale depletion is a

smaller ozone “dimple” observed during the Arctic spring over the North Pole.

Ozone at middle latitudes has declined, but by a much smaller extent (about 4–5%

decrease). If the conditions became more severe (cooler stratospheric temperatures,

more stratospheric clouds, more active chlorine), then global ozone may decrease

at a much greater pace. Standard global warming theory predicts that the

stratosphere will cool.

When the Antarctic ozone hole breaks up, the ozone-depleted air drifts out

into nearby areas. Decreases in the ozone level of up to 10% have been reported in

New Zealand in the month following the breakup of the Antarctic ozone hole.

Ozone Hole: The terms “ozone hole” refers to a large and rapid decrease in the

abundance of ozone molecules, not the complete absence of them. The Antarctic

“ozone hole” occurs during the southern spring between September and November.

The British Antarctic Survey Team first reported it in May 1985. The Team found

that for the period between September and mid November, ozone concentrations

over Halley Bay, Antarctica, had declined 40% from levels during the 1960s. Severe

depletion had been occurring since the late 1970s. Lowest value of ozone measured


by TOMS each year in the ozone hole is given in Figure 2c. Figure 2d presents the

September 2006 image of the largest Antarctic ozone hole ever recorded. Figure

2e presents the annual March of Spring (September to December) and Summer

(January to March) Antarctic total ozone based on four locations observations,

namely Argentina Island, Syowa, Halley Bay and the South Pole (WMO, Fact

Sheet). Figure 2f presents the annual march of Winter (December to March) and

Summer (May to August) Arctic total ozone from the combined long-term mean

of 12 stations North of 59 oN. Figure 2g presents the seasonal change of Antarctic

ozone at Argentina Island, Syowa and Halley Bay. The figures represent the

change during 1979-86 as % of the 1957-78. Figure 2h presents the annual march

of total ozone as deviation

from the long-term average

for four latitudinal zones of

the Northern Hemisphere

(from top to bottom —

80-60, 64-53, 52-40 & 39-

30 oN) for Winter-Spring

(December to March) and

for Summer (May to

August) – on the right side

of each chart, the numbers

indicate the long-term

mean value for each zone

in Dobson units.

Reductions of up to

70% in the ozone column


observed in the austral (Southern Hemispheric) spring over Antarctica and first

reported in 1985 are continuing. Through the 1990s, total column ozone in

September and October have continued to be 40–50% lower than pre-ozone-hole

values. In the Arctic the amount lost is more variable year-to-year than in the

Antarctic. The greatest declines, up to 30%, are in the Winter and Spring, when

the stratosphere is colder. In middle latitudes it is preferable to speak of ozone

depletion rather than holes. Declines are about 3% below pre-1980 values for 35–

60°N and about 6% for 35–60°S. In the tropics, there are no significant trends.

Predictions of ozone levels remain difficult. The WMO/UN Global Ozone Research

and Monitoring Project – Report No. 44 comes out strongly in favor for the Montreal

Protocol, but notes that a UNEP 1994 Assessment overestimated ozone loss for

the 1994–1997 period.

Is UVB increasing at surface?: Since the ozone layer absorbs UVB ultraviolet light

from the Sun, ozone layer depletion is expected to increase surface UVB levels,


which could lead to damage, including increases in skin cancer. This was the

reason for the Montreal Protocol. Although decreases in stratospheric ozone are

well-tied to CFCs and there are good theoretical reasons to believe that decreases

in ozone will lead to increases in surface UVB, there is no direct observational

evidence linking ozone depletion to higher incidence of skin cancer in human

beings. This is partly due to the fact that UVA, which has also been implicated in

some forms of skin cancer, is not absorbed by ozone, and it is nearly impossible to

control statistics for lifestyle changes in the populace.

2.5 Ozone and Policy

That ozone depletion takes place is not seriously disputed in the scientific

community. There is a consensus among atmospheric physicists and chemists that

the scientific understanding has now reached a level where counter-measures to

control CFC emissions are justified, although the decision is ultimately one for

policy-makers.

Despite this consensus, the science behind ozone depletion remains complex,

and some who oppose the enforcement of countermeasures point to some of the

uncertainties. For example, although increased UVB has been shown to constitute

a melanoma risk, it has been difficult for statistical studies to establish a direct

link between ozone depletion and increased rates of melanoma. Although melanomas

did increase significantly during the period 1970–1990, it is difficult to separate

reliably the effect of ozone depletion from the effect of changes in lifestyle factors

(e.g., increasing rates of air travel.

The detailed mechanism by which the polar ozone holes form is different

from that for the mid-latitude thinning, but the most important process in both

trends is catalytic destruction of ozone by atomic chlorine and bromine. The main

source of these halogen atoms in the stratosphere is photo-dissociation of

chlorofluorocarbons (CFC) compounds, commonly called freons, and of

bromofluorocarbon compounds known as halons. These compounds are transported

into the stratosphere after being emitted at the surface. Both ozone depletion

mechanisms strengthened as emissions of CFCs and halons increased.

Thomas Midgley invented Chlorofluorocarbons (CFCs) in the 1930s. They

were used in Air Conditioning/cooling units, as aerosol spray propellants prior to

the 1980s, and in the cleaning processes of delicate electronic equipment. They

also occur as by-products of some chemical processes. No significant natural

sources have ever been identified for these compounds — their presence in the

atmosphere is due almost entirely to human manufacture. When such ozone-

depleting chemicals reach the stratosphere, they are dissociated by ultraviolet

light to release chlorine atoms. The chlorine atoms act as a catalyst, and each can

break down tens of thousands of ozone molecules before being removed from the

stratosphere. Given the longevity of CFC molecules, recovery times are measured

in decades. It is calculated that a CFC molecule takes an average of 15 years to go

from the ground level up to the upper atmosphere, and it can stay there for about

a century, destroying up to one hundred thousand ozone molecules during that

time.


CFCs and other contributory substances are commonly referred to as ozone-

depleting substances (ODS). Since the ozone layer prevents most harmful UVB

wavelengths (270–315 nm) of ultraviolet light (UV light) from passing through the

Earth’s atmosphere, observed and projected decreases in ozone have generated

worldwide concern leading to adoption of the Montreal Protocol banning the

production of CFCs and halons as well as related ozone depleting chemicals such

as carbon tetrachloride and trichloroethane. It is suspected that a variety of biological

consequences such as increase in skin cancer, damage to plants, and reduction of

plankton populations in the ocean’s photic zone may result from the increased UV

exposure due to ozone depletion.

2.6 International Action

The first international action to focus attention on the dangers of ozone

depletion in the stratosphere and its dangerous consequences in the long run on

life on earth was focused in 1977 when in a meeting of 32 countries in Washington

D.C. a World plan on action on Ozone layer with UNEP as the coordinator was

adopted.

As experts began their investigation, data piled up and in 1985 in an article

published in the science journal, “Nature” by Dr. Farman pointed out that although

there is overall depletion of the ozone layer all over the world, the most severe

depletion had taken place over the Antarctica. This is what is famously called as

“the Antarctica Ozone hole”. His findings were confirmed by Satellite observations

and offered the first proof of severe ozone depletion and stirred the scientific

community to take urgent remedial actions in an international convention held in

Vienna on March 22, 1985. This resulted in an international agreement in 1987 on

specific measures to be taken in the form of an international treaty known as the

“Montreal Protocol” on Substances That Deplete the Ozone Layer. Under this

Protocol the first concrete step to save the Ozone layer was taken by immediately

agreeing to completely phase out chlorofluoro-carbons (CFC), Halons, Carbon

tetrachloride (CTC) and Methyl chloroform (MCF) as per a schedule.

2.6.1 Alternative Substances

In 1985 around 20 nations, including most of the major CFC producers,

signed the Vienna Convention, which established a framework for negotiating

international regulations on ozone-depleting substances. That same year, the

discovery of the Antarctic ozone hole was announced, causing a revival in public

attention to the issue. In 1987, representatives from 43 nations signed the Montreal

Protocol. Meanwhile, the halocarbon industry shifted its position and started

supporting a protocol to limit CFC production. The reasons for this were in part

explained by “Dr. Mostafa Tolba, former head of the UN Environment Programme,

who was quoted in the June 30, 1990 edition of The New Scientist, ‘...the chemical

industry supported the Montreal Protocol in 1987 because it set up a worldwide

schedule for phasing out CFCs, which [were] no longer protected by patents. This

provided companies with an equal opportunity to market new, more profitable

compounds”.


At Montreal, the participants agreed to freeze production of CFCs at 1986

levels and to reduce production by 50% by 1999. After a series of scientific

expeditions to the Antarctic produced convincing evidence that the ozone hole

was indeed caused by chlorine and bromine from manmade organohalogens, the

Montreal Protocol was strengthened at a 1990 meeting in London. The participants

agreed to phase out CFCs and halons entirely (aside from a very small amount

marked for certain “essential” uses, such as asthma inhalers) by 2000. At a 1992

meeting in Copenhagen, the phase out date was moved up to 1996.

To some extent, CFCs have been replaced by the less damaging hydro-

chlorofluorocarbons (HCFCs), although concerns remain regarding HCFCs also. In

some applications, hydro-fluorocarbons (HFCs) have been used to replace CFCs.

HFCs, which contain no chlorine or bromine, do not contribute at all to ozone

depletion although they are potent greenhouse gases. The best known of these

compounds is probably HFC-134a (R-134a), which in the United States has largely

replaced CFC-12 (R-12) in automobile air conditioners. In laboratory analytics (a

former “essential” use) the ozone depleting substances can be replaced with various

other solvents.

Ozone Diplomacy, by Richard Benedick (Harvard University Press, 1991) gives

a detailed account of the negotiation process that led to the Montreal Protocol.

Pielke and Betsill provide an extensive review of early US government responses to

the emerging science of ozone depletion by CFCs.

2.6.2 Ozone-depleting gas trends

Since the adoption and strengthening of the Montreal Protocol has led to

reductions in the emissions of CFCs, atmospheric concentrations of the most

significant compounds have been declining. These substances are being gradually

removed from the atmosphere. By 2015, the Antarctic ozone hole would have

reduced by only 1 million km² out of 25 (Newman et al., 2004); complete recovery

of the Antarctic ozone layer will not occur until the year 2050 or later. Work has

suggested that a detectable (and statistically significant) recovery will not occur

until around 2024, with ozone levels recovering to 1980 levels by around 2068.

There is a slight caveat to this, however “Global warming from CO2 is

expected to cool the stratosphere. This, in turn, would lead to a relative increase

in ozone depletion and the frequency of ozone holes. The effect may not be

linear; ozone holes form because of polar stratospheric clouds; the formation of

polar stratospheric clouds has a temperature threshold above which they will not

form; cooling of the Arctic stratosphere might lead to Antarctic-ozone-hole-like

conditions. But at the moment this is not clear”.

Even though the stratosphere as a whole is cooling, high-latitude areas may

become increasingly predisposed to springtime stratospheric warming events as

weather patterns change in response to higher greenhouse gas loading. This would

cause PSCs to disappear earlier in the season, and may explain why Antarctic

ozone hole seasons have tended to end somewhat earlier since 2000 as compared

with the most prolonged ozone holes of the 1990s. The decrease in ozone-depleting


chemicals has also been significantly affected by a decrease in bromine-containing

chemicals. The data suggest that substantial natural sources exist for atmospheric

methyl bromine (CH3Br). The 2004 ozone hole ended in November 2004, daily

minimum stratospheric temperatures in the Antarctic lower stratosphere increased

to levels that are too warm for the formation of polar stratospheric clouds (PSCs)

about 2 to 3 weeks earlier than in most recent years.

The Arctic winter of 2005 was extremely cold in the stratosphere; PSCs

were abundant over many high-latitude areas until dissipated by a big warming

event, which started in the upper stratosphere during February and spread

throughout the Arctic stratosphere in March. The size of the Arctic area of

anomalously low total ozone in 2004-2005 was larger than in any year since 1997.

The predominance of anomalously low total ozone values in the Arctic region in

the winter of 2004-2005 is attributed to the very low stratospheric temperatures

and meteorological conditions favorable for ozone destruction along with the

continued presence of ozone destroying chemicals in the stratosphere.

A 2005 IPCC summary of ozone issues observed that observations and model

calculations suggest that the global average amount of ozone depletion has now

approximately stabilized. Although considerable variability in ozone is expected

from year to year, including in polar regions where depletion is largest, the ozone

layer is expected to begin to recover in coming decades due to declining ozone-

depleting substance concentrations, assuming full compliance with the Montreal

Protocol.

Temperatures during the Arctic winter of 2006 stayed fairly close to the

long-term average until late January, with minimum readings frequently cold enough

to produce PSCs. During the last week of January, however, a major warming event

sent temperatures well above normal — much too warm to support PSCs. By the

time temperatures dropped back to near normal in March, the seasonal norm was

well above the PSC threshold. Preliminary satellite instrument-generated ozone

maps show seasonal ozone buildup slightly below the long-term means for the

Northern Hemisphere as a whole, although some high ozone events have occurred.

During March 2006, the Arctic stratosphere pole-ward of 60 degrees North Latitude

was free of anomalously low ozone areas except during the three-day period from

March 17 to 19 when the total ozone cover fell below 300 DU over part of the

North Atlantic region from Greenland to Scandinavia.

The area where total column ozone is less than 220 DU (the accepted

definition of the boundary of the ozone hole) was relatively small until around 20

August 2006. Since then the ozone hole area increased rapidly, peaking at 29

million km² September 24. In October 2006, NASA reported that the year’s ozone

hole set a new area record with a daily average of 26 million km² between 7

September and 13 October 2006; total ozone thickness fell as low as 85 DU on

October 8. The two factors combined, 2006 sees the worst level of depletion in

recorded ozone history. The depletion is attributed to the temperatures above the

Antarctic reaching the lowest recording since comprehensive records began in

1979.


The Antarctic ozone hole is expected to continue for decades. Ozone

concentrations in the lower stratosphere over Antarctica will increase by 5%–10%

by 2020 and return to pre-1980 levels by about 2060–2075, 10–25 years later than

predicted in earlier assessments. This is because of revised estimates of atmospheric

concentrations of Ozone Depleting Substances — and a larger predicted future

usage in developing countries. Another factor, which may aggravate ozone depletion,

is the drawdown of nitrogen oxides from above the stratosphere due to changing

wind patterns.

2.6.3 Man-made chlorine vs natural source

Another objection occasionally voiced is that “It is generally agreed that

natural sources of tropospheric chlorine (volcanoes, ocean spray, etc.) are four to

five orders of magnitude larger than man-made sources”. While strictly true,

tropospheric chlorine is irrelevant; it is stratospheric chlorine that matters to ozone

depletion. Chlorine from ocean spray is soluble and thus is washed out by rainfall

before it reaches the stratosphere. CFCs, in contrast, are insoluble and long-lived,

which allows them to reach the stratosphere. Even in the lower atmosphere there

is more chlorine present in the form of CFCs and related haloalkanes than there is

in HCl from salt spray, and in the stratosphere the halocarbons dominate

overwhelmingly. Only one of these halocarbons, methyl chloride, has a predominantly

natural source, and it is responsible for about 20 percent of the chlorine in the

stratosphere; the remaining 80% comes from manmade compounds.

Very large volcanic eruptions can inject HCl directly into the stratosphere,

but direct measurements have shown that their contribution is small compared to

that of chlorine from CFCs. A similar erroneous assertion is that soluble halogen

compounds from the volcanic plume of Mount Erebus on Ross Island, Antarctica

are a major contributor to the Antarctic ozone hole.

2.6.4 World Ozone Day

In 1994, the United Nations General Assembly voted to designate September

16 as “World Ozone Day”, to commemorate the signing of the Montreal Protocol

on that date in 1987. On the ozone depletion theory, though initially there was

some opposition, more particularly from the industry lobby, latter it was accepted.

This has leads in finding alternate substances to arrest this trend. However, the

long life of the ozone depleting substances in the atmosphere, it may take time to

stabilize the ozone process to pre-ozone depleting substances level. This is success

story of science.

2.7 Impact on Environment

2.7.1 Effects on life forms on the Earth

A recent assessment made by a panel of UNEP experts gives a detailed

account of the impacts of ozone depletion on human health, animals, plants,

microorganisms, materials and air quality.


Effects on Human & Animal Health: Increased penetration of solar UV-B radiation

is likely to have profound impact on human health with potential risks of eye

diseases, skin cancer and infectious diseases. UV radiation is known to damage

the cornea and lens of the eye. Chronic exposure to UV-B could lead to cataract of

the cortical and posterior subcapsular forms. UV-B radiation can adversely affect

the immune system causing a number of infectious diseases. In light skinned

human populations, it is likely to develop nonmelanoma skin cancer (NMSC).

Experiments on animals show that UV exposure decreases the immune response

to skin cancers, infectious agents and other antigens

Effects on Terrestrial Plants: It is a known fact that the physiological and

developmental processes of plants are affected by UV-B radiation. Scientists believe

that an increase in UV-B levels would necessitate using more UV-B tolerant cultivar

and breeding new tolerant ones in agriculture. In forests and grasslands increased

UV-B radiation is likely to result in changes in species composition (mutation) thus

altering the bio-diversity in different ecosystems. UV-B could also affect the plant

community indirectly resulting in changes in plant form, secondary metabolism,

etc. These changes can have important implications for plant competitive balance,

plant pathogens and bio-geochemical cycles.

Effects on Aquatic Ecosystems: While more than 30 percent of the world’s

animal protein for human consumption comes from the sea alone, it is feared that

increased levels of UV exposure can have adverse impacts on the productivity of

aquatic systems. High levels of exposure in tropics and subtropics may affect the

distribution of phytoplanktons which form the foundation of aquatic food webs.

Reportedly a recent study has indicated 6-12 percent reduction in phytoplankton

production in the marginal ice zone due to increases in UV-B. UV-B can also cause

damage to early development stages of fish, shrimp, crab, amphibians and other

animals, the most severe effects being decreased reproductive capacity and impaired

larval development.

Effects on Bio-geo-chemical Cycles: Increased solar UV radiation could affect

terrestrial and aquatic bio-geo-chemical cycles thus altering both sources and sinks

of greenhouse and important trace gases, e.g. carbon dioxide (CO2), carbon

monoxide (CO), carbonyl sulphide (COS), etc. These changes would contribute to

biosphere-atmosphere feedbacks responsible for the atmosphere build-up of these

gases. Other effects of increased UV-B radiation include: changes in the production

and decomposition of plant matter; reduction of primary production changes in

the uptake and release of important atmospheric gases; reduction of

bacterioplankton growth in the upper ocean; increased degradation of aquatic

dissolved organic matter (DOM), etc. Aquatic nitrogen cycling can be affected by

enhanced UV-B through inhibition of nitrifying bacteria and photo-decomposition

of simple inorganic species such as nitrate. The marine sulphur cycle may also be

affected resulting in possible changes in the sea-to-air emissions of COS and


dimethylsulfied (DMS), two gases that are degraded to sulphate aerosols in the

stratosphere and troposphere, respectively.

Effects on Air Quality: Reduction of stratospheric ozone and increased penetration

of UV-B radiation result in higher photo-dissociation rates of key trace gases that

control the chemical reactivity of the troposphere. This can increase both production

and destruction of ozone and related oxidants such as hydrogen peroxide, which

are known to have adverse effects on human health, terrestrial plants and outdoor

materials. Changes in the atmospheric concentrations of the hydroxyl radical (OH)

may change the atmospheric lifetimes of important gases such as methane and

substitutes of chlorofluorocarbons (CFCs). Increased tropospheric reactivity could

also lead to increased production of particulates such as cloud condensation nuclei

from the oxidation and subsequent nucleation of sulphur of both anthropogenic

and natural origin (e.g. COS and DMS).

Effects on Materials: Increased levels of solar UV radiation is known to have adverse

effects on synthetic polymers, naturally occurring biopolymers and some other

materials of commercial interest. UV-B radiation accelerates the photodegradation

rates of these materials thus limiting their lifetimes. Typical damages range from

discoloration to loss of mechanical integrity. Such a situation would eventually

demand substitution of the affected materials by more photostable plastics and

other materials in future.

2.7.2 Effects on Global Warming

One of the strongest predictions of the greenhouse effect theory proponents

is that the stratosphere will cool. The same CO2 radiative forcing that produces

near-surface global warming is expected to cool the stratosphere. This cooling, in

turn, is expected to produce a relative increase in ozone (O3) depletion and the

frequency of ozone holes. Conversely, ozone depletion represents a “radiative

forcing” of the climate system. There are two opposing effects: Reduced ozone

causes the stratosphere to absorb less solar radiation, thus cooling the stratosphere

while warming the troposphere; the resulting colder stratosphere emits less long-

wave radiation downward, thus cooling the troposphere. Overall, the cooling

dominates; the IPCC concludes that “observed stratospheric O3 losses over the

past two decades have caused a negative forcing of the surface-troposphere system”

of about -0.15 ± 0.10 watts per square meter (W/m²)”. It is also said that although

this cooling has been observed, it is not trivial to separate the effects of changes

in the concentration of GHGs and ozone depletion since both will lead to cooling.

Results from the National Oceanic and Atmospheric Administration’s Geophysical

Fluid Dynamics Laboratory show that above 20 km (12.4 miles), the GHGs dominate

the cooling. Ozone depleting chemicals are also GHGs. The increases in

concentrations of these chemicals have produced 0.34 ± 0.03 W/m² of radiative

forcing, corresponding to about 14% of the total radiative forcing from increases

in the concentrations of well-mixed greenhouse gases.

The long-term modeling of the process, its measurement, study, design of

theories and testing take decades to both document, gain wide acceptance, and


ultimately become the dominant paradigm. Several theories about the destruction

of ozone were hypothesized in the 1980s, published in the late 1990s, and are

currently being proven. Dr Drew Schindell, and Dr Paul Newman, NASA Goddard,

proposed a theory in the late 1990s, using a SGI Origin 2000 supercomputer, that

modeled ozone destruction, accounted for 78% of the ozone destroyed. Further

refinement of that model accounted for 89% of the ozone destroyed, but pushed

back the estimated recovery of the ozone hole from 75 years to 150 years. An

important part of that model is the lack of staratospheric flight due to depletion

of fossil fuels.

Ozone, while a minority constituent in the Earth’s atmosphere, is responsible

for most of the absorption of UVB radiation. The amount of UVB radiation that

penetrates through the ozone layer decreases exponentially with the slant-path

thickness/density of the layer. Correspondingly, a decrease in atmospheric ozone

is expected to give rise to significantly increased levels of UVB near the surface.

Increases in surface UVB due to the ozone hole can be partially inferred by radiative

transfer model calculations, but cannot be calculated from direct measurements

because of the lack of reliable historical (pre-ozone-hole) surface UV data, although

more recent surface UV observation measurement programmes exist. Because it is

this same UV radiation that creates ozone in the ozone layer from O2 (regular

oxygen) in the first place, a reduction in stratospheric ozone would actually tend

to increase photochemical production of ozone at lower levels (in the troposphere),

although the overall observed trends in total column ozone still show a decrease,

largely because ozone produced lower down has a naturally shorter photochemical

lifetime, so it is destroyed before the concentrations could reach a level which

would compensate for the ozone reduction higher up. At this time, ozone at

ground level is produced mainly by the action of UV radiation on combustion

gases from vehicle exhausts, discussed in previous chapter.

More often ozone depletion and global warming are interlinked in the mass

media but in reality the connection between global warming and ozone depletion

is not strong. The major component for stratospheric cooling the formation of

circum-polar vortex more frequent at South Pole and less frequent at North Pole,

which is corroborated with the observed ozone depletion patterns with latitude

and season as well with South & North Poles as discussed above. Also, the

downward long wave radiation from the stratospheric layer is insignificant in general.

With all these arguments, yet it is pertinent to see that with the non-ozone depleting

alternate substances introduction, the issue of stratospheric ozone is of not much

significance but yet the alternate substances are still come under GHGs along

with tropospheric ozone formation.


Chapter 3

Solar Radiation

3.1 What is Solar Radiation?

Solar radiation is a general term for the electromagnetic radiation emitted

by the Sun. It is radiant energy emitted by the Sun as a result of its nuclear fusion

reactions. We can capture and convert solar radiation into useful forms of energy,

such as heat and electricity, using a variety of technologies. The technical feasibility

and economical operation of these technologies at a specific location depends on

the available solar radiation. The spectrum of the Sun’s solar radiation (Figure 2a)

is close to that of a black body with a temperature of about 5,800 0K [degrees

absolute] » 6000 0K. The Sun emits radiation (energy) in different wavelengths/

bands, starting from X-rays (lower bandwidth side), g-rays, ultra-violet, visible,

infrared (higher bandwidth side). The wavelength in which maximum energy is

emitted depends upon the temperature of the emitting surface (the Sun, the

Earth, or any other object). According to Plank’s Law the wavelength at which

the maximum energy is emitted (λm) is given as:

λm = a/T

where ‘a’ is the constant given by 2830 and T is the emitting body’s surface

temperature, given in degrees absolute (at zero degrees Celsius it is 273 degrees

Absolute or Kelvin). The Sun’s surface temperature is around 6000 0C and the

Earth’s surface temperature is around 10 0C. Thus the wavelength at which the

maximum energy is located is given as:

The Sun: (λm) = 2830/(6000 + 273) = 0.45 microns (mm) – short wave radiation;

The Earth: (λm) = 2830/(10 + 273) = 10.0 microns (mm) – long wave radiation;

Thus, the Sun emits maximum energy around 0.5μm wavelengths and the

Earth emits at around 10μm wavelength. The former is known as short-wave

radiation or visible radiation and later is known as long-wave radiation or infrared

radiation.

Solar Constant: The Solar constant is the amount of the Sun’s incoming

electromagnetic radiation (Solar Radiation) per unit area, measured on the outer

surface of the Earth’s Atmosphere – at the top of the atmosphere — in an aircraft

perpendicular to the rays. The Solar constant includes all types of the solar radiation,

not just the visible light. It is measured by satellite to be roughly 1,366 watts per

square meter (W/m²), though this fluctuates by about 6.9% during a year (from

1,412 W/m² in early January to 1,321 W/m² in early July) due to the Earth’s

varying distance from the Sun, and by a few parts per thousand from day to day.

Thus, for the whole Earth (which has a cross section of 127,400,000 km2), the

power is 1.740 x 1017 W, plus or minus 3.5%. Thus, the solar radiation reaching

on an average on the top of the atmosphere is constant averaging about 1.96 ly/


min [calories per minute per square centimeter, or Langley’s per minute]; this is

equivalent to 1,366 W/m².

Solar Radiation: The Earth receives a total amount of radiation determined by its

cross section, but as it rotates this energy is distributed across the entire surface

area. Hence the average incoming Solar radiation (sometimes called the Solar

irradiance), taking in to account the angle at which the rays strike and that at any

one moment half the planet does not receive any solar radiation, is one-fourth the

solar constant (approximately 342 W/m²).

The amount of solar radiation actually reaching the atmosphere at any given

place on the top of the atmosphere varies over the solar constant with the latitude

and declination of the Sun and seasons. Thus, the amount of radiation received at


the top of the free atmosphere at a given point (Ra, in ly/day) is given as (Fitz,

1949):

Ra = 2.0 x (sin φ x sin δ + cos φ x cos δ x cosh)

Where φ is the latitude of the place in degrees; δ is the declination of the

Sun that varies with the seasons between 230 27’ N to 230 27’ S latitude (on

March 23rd and September 22nd it is zero as the Sun is on equator and while on

June 22nd and December 23rd at the two extremes]; and h is the hour angle of

the Sun in degrees. Figure 3a presents the distribution of solar radiation received

on the top of the free atmosphere (Ra) over different latitudes and seasons both in

the Northern & Southern Hemispheres (estimated using the above equation). The

values of January to December in Northern Hemisphere respectively refer to July

to June values of Southern Hemisphere.

3.2 Types of Radiation

A typical Earth’s radiation budget is shown in Figure 3b. The incoming

solar energy (Ra) is reflected by atmosphere around 6%, by clouds around 20%,

by the Earth’s surface by around 4%; absorbed by atmosphere around 16%, by

clouds by around 3%, by land and oceans by around 51%; radiated back to space

by clouds and atmosphere is around 64%, radiation absorbed by atmosphere by

around 15%, radiated directly to space from the Earth by around 6%; conduction

and rising air by around 7%; carried to clouds and atmosphere by latent heat in

water vapour by around 23%. However, all these vary with place and time and

year. This gives only how the radiation budget is distributed in the Earth –

Atmosphere system. This is divided into net short wave radiation and net long

wave radiation.

3.2.1 Global Solar Radiation

The amount of solar radiation actually reaching the Earth’s surface passing

the atmosphere at any given place and time is quite different from the values seen

in Figure 3a. Every location on the Earth receives sunlight at least part of the

year. The amount of solar radiation that reaches any one “spot” on the Earth’s

surface varies according to the Geographic location, Time of the day, Season,

Local landscape, Local weather. Because the Earth is round, the Sun strikes the

surface at different angles ranging from 0º (just above the horizon) to 90º (directly

overhead). The day light hours at any given point on the Earth on a given day (N)

is given as:

N = (2/15) x cos-1 (- tan φ x tan δ)

At the equator N is 12 hours in all the months (that is, day & night are

equal) and from 660 27’ to poles it is 6 months day and 6 months night – in the

Southern Hemisphere if it is night for 6 months, then the Northern Hemisphere

presents 6 months day and vice-versa. In between these two conditions, N varies

between 0 to 24 based on the season and location. The January to December in

Northern Hemisphere respectively refer to July to June in the Southern Hemisphere.


When the Sun’s rays are vertical, the Earth’s surface gets all the energy

possible. The more slanted the Sun’s rays are, the longer they travel through the

atmosphere, becoming more scattered and diffuse. Because the Earth is round, the

frigid polar-regions never get a high sun, and because of the tilted axis of rotation,

these areas receive no sun at all during part of the year. The Earth revolves around

the Sun in an elliptical orbit and is closer to the Sun during part of the year. When

the Sun is nearer the Earth, the Earth’s surface receives a little more solar energy.

The Earth is nearer the Sun when it’s summer in the Southern Hemisphere and

winter in the Northern Hemisphere. However the presence of vast oceans moderates

the hotter summers and colder winters one would expect to see in the Southern

Hemisphere as a result of these differences.

The 23.50

tilts in the Earth’s axis of rotation is a more significant factor in

determining the amount of sunlight striking the Earth at a particular location.

Thus, tilting results in longer days in the Northern Hemisphere from the spring

(vernal) equinox to the fall (autumnal) equinox and longer days in the Southern

Hemisphere during the other six months. The rotation of the Earth is responsible

for hourly variations in sunlight. In the early morning and late afternoon, the Sun

is low in the sky. Its rays travel further through the atmosphere than at noon when

the Sun is at its highest point. On a clear day, the greatest amount of solar energy

reaches a solar collector around solar noon. Thus, at any given moment, the amount

of the solar radiation received at a location on the Earth’s surface depends on the

state of the atmosphere/weather and the location’s latitude and season. In addition,

the solar energy while passing through the atmosphere, some of it is partially

depleted and attenuated as it traverses the atmospheric layers from the top of the

atmosphere, preventing substantial portion of it from reaching the Earth’s surface.

This phenomenon is due to absorption, scattering, and reflection in the atmosphere

(Figure 3b). The solar radiation is reflected and scattered primarily by clouds

(moisture & ice particles), particulate matter (dust, smoke, haze and smog), and

various other gases. After modification some of this again reaches the Earth’s

surface. This part is known as diffuse radiation. However, major part of the energy

directly reaches the Earth’s surface. The direct plus the diffuse radiation that

reaches the Earth’s surface is known as global solar radiation or total solar radiation

or short wave radiation. Atmospheric condition reduces direct beam radiation by

10% on clear, dry days and by 100% during thick, cloudy days.

3.2.2 Net Radiation Balance

The global solar radiation reaching the surface partly reflected back to the

atmosphere and the ground absorbs the remaining part. The reflected part of

radiation depends upon the albedo (ratio of reflected to incident radiation). The

albedo varies with reflecting surface. That is the reflection depends on the nature

of the surface and its cover and is approximately 5 to 7% for water and around 15

to 25% for most crops. This fraction varies with the degree of crop cover and

wetness of the exposed soil surface. White bodies like snow reflects maximum and

black bodies reflects minimum. That which remains is “net short wave radiation”.

The Earth emits part of the absorbed radiation in long wave band known as infrared


band. This also follows the same as albedo. That is white bodies emit less and

black bodies emit more. That is, black bodies are efficient absorbers and as well

efficient emitters. Some of the radiation leaving the Earth’s surface in long wave

will be reached back through reflection and absorption/emission process. The

difference between the out-going and in-coming long wave radiation is called “net

long wave radiation”. The net balance of net short wave and net long wave is

known as net radiation balance.

If the net long wave radiation is more than the net short wave radiation

then the net radiation is negative and vice versa case the net radiation is positive.

This is recorded using net radiation balance meters. However, because of high

costs, both global solar radiation and net radiation balance measuring instruments

are located at few locations when compared to the measurements of other

meteorological parameters. In view of this, these parameters are derived indirectly

using other meteorological parameters (Reddy, 1987).

The atmosphere absorbs long wave radiation more effectively than it does

the short wave radiation emitted by the Sun. The absorption of this long wave

radiation warms the atmosphere, transfer of sensible and latent heat also warms

the atmosphere from the surface. The proponents of global warming, greenhouse

gases [GHG] like water vapour, Carbon Dioxide (CO2), Methane (CH

4), Nitrous

Oxide (N2O) and Chlorofluorocarbons (CFCs) play an important role in the warming.

It is argued that GHGs also emit long wave radiation both upward to space and

downward to the surface. It is also argued that the downward part of this long-

wave radiation emitted by the atmosphere is the “greenhouse effect.” In fact the

term “Greenhouse effect” is a misnomer, as this process is not the mechanism that

warms greenhouses. The warming also depends upon the emitting surface and its’

surrounding conditions. The warming relates to the net long wave radiation. That

is the balance between the out going and incoming long wave radiation at the

Earth’s surface.

Reports present absorption characteristics of major GHGs. The same reports

also state that it is not possible to state that a certain gas causes a certain

percentage of the greenhouse effect. That is, these are speculative values vary

with atmospheric composition at any given point of time over a given place. That

means this depends up on the state of atmosphere and relative interaction capacity.

3.3 Radiation Climatology

Let us see the models to estimate global solar radiation & net radiation

balance, to understand the localized influences on global solar radiation that is

reaching Earth’s surface and net radiation balance at the Earth surface.

Models: As the global solar radiation (Rt) and net radiation balance (Rn) measured

at few selected locations, these are derived indirectly using other meteorological

parameters using empirical formulae as they are part of major input in to several

studies, more particularly in the estimation of evaporation & evapotranspiration.

Reddy (1971a & b, 1981) & Reddy & Rao (1973) presented models to estimate Rt

& Rn. They are given as follows:


Rt = K [(1+0.8s) x (1-0.2t)/(0.1 x √h’)

Rn= K (0.6+0.02Ts-0.04√h’)-h’ (4.3-√-T)

K is the radiation constant at the surface of the observations in ly/day (cal/cm2/

day)

K = (N/12) x (lN+ ϕij cos φ) x 102

l = 0.2/(1+0.1φ) – latitude factor; ϕij = seasonal factor (i = 1, 2, 3 in

which 1, 2 and 3 stand for inland, coastal & hill stations, respectively, and j = 1,

2, — 12, in which 1 to 12 stand for January to December in the Northern Hemisphere

and respectively refer to July to June in the Southern Hemisphere. These are

given in Figure 3c. In the case of hill stations height correction factor is added as:

K = K + 0.005H (12-N) in which H is the height of the place above mean sea level

in meters; s = n/N where n is the mean hours of bright sunshine per day during a

month & N is the mean length of the day in a given month. n is measured using

Sunshine recorder or in the absence of measured data, this can be estimated using

the model (Reddy, 1974) as follows: s = 1 – φ1 – f2; where φ1 = a x e-0.25√a and

a = (Cl + Cm +Ch)/8 in which Cl, Cm & Ch respectively are the amounts of low,

medium & high clouds, mean of 0830 & 1730 hours IST observations, in octas,

varies between 0 and 1 as sky condition change from clear (zero octas) to overcast

(8 octas) and e is the exponential function; and f2 = 0.02 + 0.08 cos 4φ upto 450

latitude and = –0.06 for latitudes beyond 450 latitude; t = r/M where r is the

number of rainy days during the month and M is the number of days in the month;

h’ is the mean relative humidity per day in the month. If h’ ≤ 36% then h’ = 35%

only; T is the mean

daily screen

temperature during the

month in oC. √-T is

taken as -√T.

Alternative Model-1:

Where the above-

presented data sets are

not available, alternate

approach using the

rainfall data, that is

recoded at widely, is

presented by Reddy, et

al. (1984) for northeast

Brazil. This is given as

follows: Rt = a + b (φ)

+ c (P1/3); where φ is

the latitude in degrees

and P is the

precipitation in mm &

a, b & c are constants


derived for northeast Brazil [in the Southern Hemisphere] are given below

(Table 3):

Table 3: Regression parameters vs Calendar months

Months a b c

N.H. S.H.

January July 444 - 2.00 -12.07

February August 501 - 1.00 -13.20

March September 523 0.70 -15.00

April October 517 4.70 -20.20

May November 543 10.66 -35.79

June December 510 10.59 -30.07

July January 532 15.17 -40.80

August February 608 8.50 -44.44

September March 685 3.70 -44.80

October April 551 0.50 -23.70

November May 477 - 1.50 -16.91

December June 442 - 2.00 -14.00

N.H. = Northern Hemisphere; S.H. = Southern Hemisphere

Alternative Model 2: To derive Rt and Rn for longer series to carryout power

spectrum analysis Reddy, et al. (1977) presented: Rt = a x L x √ es & Rn =

b x L x Tw and L = (1013.2/p)B x (N/12.5) and B = 1.5 x log φ; where a and b are

constants (varying with seasons) given below (Table 4), es is the saturation vapour

pressure in mb of mean surface temperature in absolute scale, Tw is the wet bulb

temperature in 0C, L is the latitude and height correction factor, p is the station

level pressure in mb.

Table 4: Variation of “a” & “b” and “c” with seasons

Month a b c

January 90.0 8.50 11.4

February 97.0 9.50 11.8

March 93.0 9.75 12.8

April 85.0 10.63 13.0

May 77.0 9.75 12.2

June 65.0 8.50 11.5

July 60.0 8.75 10.0

August 63.0 9.37 10.0

September 70.0 9.37 10.6

October 74.0 9.00 11.4

November 80.8 8.13 11.4

December 85.0 7.50 11.4

Reddy (1976a) found a good relationship between the wet bulb temperatures

(Tw, 0C ) and precipitable water (W, gm/cm2) by an equation W = c [Tw]2 in


which c is given in Table 4. The total moisture content of the atmosphere is

expressed as precipitable water vapour in the atmosphere. This is defined as the

depth of liquid water that result by condensing all the vapour in a vertical column

of the atmosphere over one square centimeter cross section. That mean Rn formula

takes into account the moisture content in the vertical column of the atmosphere.

Spatial Distribution: Reddy & Rao (1976) presented spatial distribution of Rt &

Rn over India as estimated using models of Reddy (1971 a & b; 1981) & Reddy &

Rao (1973). Figures 3d & e present spatial distribution of Rt & Rn over India,

respectively for four representative months. Reddy (1976b) presented the spatial

distribution of W over India that matches well with Rn data presented in Figure

3e. Reddy, et al., (1984) presented Rt distribution over northeast Brazil using their

model (presented above). Figure 3f presents the spatial distribution of Rt for four

representative months. The differences between theoretical and observed solar

radiation at the top of the atmosphere and that actually reaching the ground by

passing through the intervening atmosphere (Figure 3b) can be seen from Figure

3a and Figures3 d & f in space and time scales. They are quite different over

different parts of the globe over different seasons.

The above-presented equations clearly demonstrate that the moisture in the

atmosphere plays the major role in both the short & long wave radiation balance at

the Earth’s surface. However, the interactive effect varies with latitude & seasons

on the one hand and land-sea-hill on the other.


Chapter 4

Weather & Climate

4.1 What is Weather & Climate?

Weather: Weather is the mix of events that happen each day in our atmosphere

including temperature, humidity, precipitation, cloudiness, brightness, visibility,

wind, and atmospheric pressure. There are really a lot of other components to

weather, namely sunshine, rain, cloud cover, winds, hail, snow, sleet, freezing rain,

flooding, blizzards, ice storms, thunderstorms, steady rains from a cold front or

warm front, excessive heat, heat waves, excessive cold, cold waves and more.

Weather is basically the way the atmosphere is behaving, mainly with respect

to its effects upon life and human activities. Weather is not the same everywhere.

Perhaps it is hot, dry and sunny today where you live, but in other parts of the

world it is cloudy, raining or even snowing. Everyday, weather events are recorded

and predicted by meteorologists worldwide. In order to help people be prepared to

face all of these, National Weather Services (NWS), in India we have “Indian

Meteorological Department” (IMD), are the lead forecasting outlet for the nation’s

weather. They also provide Special Weather Statements and Short and Long Term

Forecasts. NWS also issues a lot of notices concerning marine weather for boaters

and others who dwell or are staying near shorelines.

Climate: Climate is the average weather pattern at a place. In most places, weather

can change from minute-to-minute, hour-to-hour, day-to-day, and season-to-season.

Climate, however, is the average of weather over time and space. An easy way to

remember the difference is that climate is what you expect, like a very hot summer,

and weather is what you get, like a hot day with pop-up thunderstorms.

Meteorologists record the weather every day. The constant recording of weather

information helps to determine the climate of an area. Climate is useful for weather

forecasting. It also helps determine when the best time would be for farmers to

plant their crops. It could even be helpful for you and your family to plan a vacation.

In short, climate is the description of the long-term pattern of weather in a particular

area.

Some scientists define climate as the average weather for a particular region

and time period, usually taken over 30-years. It’s really an average pattern of weather

for a particular region. However, this gives wrong signal in areas with systematic

variations in a given meteorological parameter. It is also true in areas where the

ecological changes influencing the weather. The averages of weather taking into

account these factors provide meaningful climate of the place.

When scientists talk about climate, they’re looking at averages of precipitation,

temperature, humidity, sunshine, wind velocity, phenomena such as fog, frost, and

hail storms, and other measures of the weather that occur over a long period in a

particular place. For example, after looking at rain gauge data, lake and reservoir


levels, and satellite data, scientists can tell if during a summer, an area was drier

than average. If it continues to be drier than normal over the course of many

summers, than it would likely indicate a change in the climate.

The reason for studying climate and a changing climate is important in

many ways as it will affect people around the world: The changing local & regional

climates could alter forests, crop yields, and water supplies; & it could also affect

human health, animals, and many types of ecosystems. Deserts may expand into

existing rangelands, and features of some of our National Parks and National

Forests may be permanently altered. Our weather is always changing and now

scientists are discovering that our climate does not stay the same either. Climate,

the average weather over a period of many years, differs in regions of the world

that receive different amounts of sunlight and have different geographic factors,

such as proximity to oceans, altitude, etc.

4.2 World Climates

Climate is the characteristic condition of the atmosphere near the Earth’s

surface at a certain place on the Earth. It is the long-term weather of that area (at

least 30 years). This includes the region’s general pattern of weather conditions,

seasons and weather extremes like hurricanes, Typhoons, cyclones, droughts, floods,

or rainy periods. Two of the most important factors determining an area’s climate

are air temperature and precipitation. World biomes are controlled by climate. The

climate of a region will determine what plants will grow there, and what animals

will inhabit it. All three components, climate, plants and animals are interwoven to

create the fabric of a biome.

4.2.1 Some Facts About Climate

Geographical effect: The sun’s rays hit the equator at a direct angle between 23°

27’N and 23° 27’S latitude. Radiation that reaches the atmosphere here is at its

most intense. In all other cases, the rays arrive at an angle to the surface and are

less intense. The closer a place is to the poles, the smaller the angle and therefore

the less intense the radiation. Our climate system is based on the location of these

hot and cold air-mass regions and the atmospheric circulation created by trade

winds and westerlies. Trade winds North of the equator blow from the Northeast.

South of the equator, they blow from the Southeast. The trade winds of the two

hemispheres meet near the equator, causing the air to rise. As the rising air-cools,

clouds and rain develop. The resulting bands of cloudy and rainy weather near the

equator create tropical conditions. Westerlies blow from the Southwest on the

Northern Hemisphere and from the Northwest in the Southern Hemisphere.

Westerlies steer storms from West to East across middle latitudes. Both westerlies

and trade winds blow away from the 30° latitude belt. Over large areas centered at

30° latitude, surface winds are light. Air slowly descends to replace the air that

blows away. Any moisture the air contains evaporates in the intense heat. The

tropical deserts, such as the Sahara of Africa, Thar in India and the Sonoran of

Mexico, exist under these regions.


Seasons: The Earth rotates about its axis, which is tilted at 23.5 degrees. This tilt

and the Sun’s radiation result in the Earth’s seasons. The Sun emits rays that hit

the Earth’s surface at different angles. These rays transmit the highest level of

energy when they strike the Earth at a right angle (90 °). Temperatures in these

areas tend to be the hottest places on the Earth. Other locations, where the Sun’s

rays hit at lesser angles, tend to be cooler. As the Earth rotates on it’s tilted axis

around the Sun, different parts of the Earth receive higher and lower levels of

radiant energy . This creates the seasons.

4.2.2 Types of Climates

Classification of Climates: The purpose of climatic classification is to identify

those aspects of climate, which distinguish a region from nearby regions and to

draw inferences on the influence of climatic factors on human, animal and plant

life. In an environmental context this may allow areas to be characterized and

boundaries to be drawn around contiguous areas that can be regarded as

homogeneous in certain respects. Under given climatic conditions there are

similarities in natural vegetation, soils, crop probabilities, etc. Broad areas exit

with climatic homogeneity, which allows a simple classification to be an aid to

study and understand the Earth’s land and people. Reddy (1983a & b) presented

reviews of climatic classification procedures. For the present purpose selected the

Koppen’s classification procedure (Koppen, 1936) as it is the most widely used

“generalized climatic classification system of the world”.

Köppen Climate Classification System: In the Koppen classification system the

Earth’s surface is divided into climatic regions that generally coincided with world

patterns of vegetation and soils [Figure 4a]. The system recognizes five major

climate types based on the annual and monthly averages of temperature and

precipitation. Each type is designated by a capital letter.

A - Moist Tropical Climates are known for their high temperatures year round and

for their large amount of year round rain;

B - little rain and a huge daily temperature range characterize Dry Climates. Two

subgroups, S - semiarid or steppe, and W - arid or desert, are used with the B

climates;

C - In Humid Middle Latitude Climates land/water differences play a large part.

These climates have warm, dry summers and cool, wet winters;

D - Continental Climates can be found in the interior regions of large landmasses.

Total precipitation is not very high and seasonal temperatures vary widely;

E - Cold Climates are part of areas where permanent ice and tundra are always

present. Only about four months of the year have above freezing temperatures;

A second, lower case letter designates further subgroups that distinguish specific

seasonal characteristics of temperature and precipitation;

f - Moist with adequate precipitation in all months and no dry season. This letter

usually accompanies the A, C, and D climates;


m - Rainforest climate in spite of short, dry season in monsoon type cycle. This

letter only applies to A climates;

s - Dry season in the summer of the respective hemisphere (high-sun season);

w - Dry season in the winter of the respective hemisphere (low-sun season);

To further denote variations in climate, a third letter was added to the code.

a - Hot summers where the warmest month is over 22°C (72°F). These can be

found in C and D climates;

b - Warm summer with the warmest month below 22°C (72°F). These can also be

found in C and D climates;

c - Cool, short summers with less than four months over 10°C (50°F) in the C and

D climates;

d - Very cold winters with the coldest month below -38°C (-36°F) in the D climate

only;

h - Dry-hot with a mean annual temperature over 18°C (64°F) in B climates only;

k - Dry-cold with a mean annual temperature under 18°C (64°F) in B climates only.

Three basic climate groups: Three major climate groups show the dominance of

special combinations of air-mass source regions.

Group1: Low Latitude Climates

These climates are controlled by equatorial tropical air masses.

Tropical Moist Climates (Af) — Rainforests: Rainfall is heavy in all months. The

total annual rainfall is often more than 250 cm (100 in). There are seasonal

differences in monthly rainfall but temperatures of 27°C (80°F) mostly stay the

same. Humidity is between 77 and 88%. High surface heat and humidity cause

cumulus clouds to form early in the afternoons almost every day.

The climates on the eastern sides of continents are influenced by maritime

tropical air masses. These air masses flow out from the moist western sides of

oceanic high-pressure cells, and bring lots of summer rainfall. The summers are

warm and very humid. It also rains a lot in the winter: Average temperature: 18 °C

(°F); Annual Precipitation: 262 cm (103 in); Latitude Range: 10° S to 25 ° N;

Global Position: Amazon Basin, Congo Basin of equatorial Africa, East Indies, from

Sumatra to New Guinea.

Wet-Dry Tropical Climates (Aw) — Savanna: A seasonal change occurs between

wet tropical air masses and dry tropical air masses. As a result, there is a very wet

season and a very dry season. Trade winds dominate during the dry season. It gets

a little cooler during this dry season but will become very hot just before the wet

season: Temperature Range: 16 °C; annual Precipitation: 0.25 cm (0.1 in). All

months less than 0.25 cm (0.1 in); Latitude Range: 15 ° to 25 ° N and S; Global

Range: India, Indochina, West Africa, southern Africa, South America and the

north coast of Australia


Dry Tropical Climate (BW) — Desert biome: These desert climates are found in

low-latitude deserts approximately between 18° to 28° in both hemispheres. These

latitude belts are centered on the tropics of Cancer and Capricorn, which lie just

north and south of the equator. They coincide with the edge of the equatorial

subtropical high-pressure belt and trade winds. Winds are light, which allows for

the evaporation of moisture in the intense heat. They generally flow downward so

the area is seldom penetrated by air masses that produce rain. This makes for a

very dry heat. The dry arid desert is a true desert climate, and covers 12 % of the

Earth’s land surface: Temperature Range: 16° C; Annual Precipitation: 0.25 cm

(0.1 in) with all months less than 0.25 cm (0.1 in); Latitude Range: 15° - 25° N

and S; Global Range: southwestern United States and northern Mexico, Argentina,

north Africa, south Africa, central part of Australia.

Group 2: Mid Latitude Climates

Climates in this zone are affected by two different air masses. The tropical

air masses are moving towards the poles and the polar air masses are moving

towards the equator. These two air masses are in constant conflict. Either air mass

may dominate the area, but neither has exclusive control.

Dry Mid-latitude Climates (BS) — Steppe: Characterized by grasslands,

this is a semiarid climate. It can be found between the desert climate (BW) and

more humid climates of the A, C, and D groups. If it received less rain, the steppe

would be classified as an arid desert. With more rain, it would be classified as a tall

grass prairie.

This dry climate exists in the interior regions of the North American and

Eurasian continents. Moist ocean air masses are blocked by mountain ranges to

the west and south. These mountain ranges also trap polar air in winter, making

winters very cold. Summers are warm to hot: Temperature Range: 24° C (43° F);

Annual Precipitation: less than 10 cm (4 in) in the driest regions to 50 cm (20 in) in

the moister steppes; Latitude Range: 35° - 55° N; Global Range: Western North

America (Great Basin, Columbia Plateau, Great Plains), Eurasian interior, from steppes

of eastern Europe to the Gobi Desert and North China.

Mediterranean Climate (Cs) — Chaparral biome: This is a wet-winter, dry-summer

climate. Extremely dry summers are caused by the sinking air of the subtropical

highs and may last for up to five months.

Plants have adapted to the extreme difference in rainfall and temperature

between the Winter and the Summer seasons. Clerophyll plants range in formations

from forests, to woodland, and scrub. Eucalyptus forests cover most of the chaparral

biome in Australia. Fires occur frequently in Mediterranean climate zones:

Temperature Range: 7 °C (12 °F); Annual Precipitation: 42 cm (17 in); Latitude

Range: 30° - 50° N and S; Global Position: central and southern California, coastal

zones bordering the Mediterranean Sea, coastal Western Australia and South

Australia, Chilean coast, Cape Town region of South Africa.


Dry Mid-latitude Climates (Bs) — Grasslands biome: These dry climates are

limited to the interiors of North America and Eurasia. Ocean air masses are blocked

by mountain ranges to the west and south. This allows polar air masses to dominate

in winter months. In the summer, a local continental air mass is dominant. A small

amount of rain falls during this season. Annual temperatures range widely. Summers

are warm to hot, but winters are cold Temperature Range: 31 °C (56°F); Annual

Precipitation: 81 cm (32 in); Latitude Range: 30° - 55° N and S; Global Position:

western North America (Great Basin, Columbia Plateau, Great Plains), Eurasian

interior.

Moist Continental Climate (Cf) — Deciduous Forest biome: This climate is in

the polar front zone - the battleground of polar and tropical air masses. Seasonal

changes between summer and winter are very large. Daily temperatures also change

often. Abundant precipitation falls throughout the year. It is increased in the

summer season by invading tropical air masses. Cold winters are caused by polar

and arctic masses moving south: Temperature Range: 31 °C (56 ° F); Average

Annual Precipitation: 81 cm (32 in); Latitude Range: 30° - 55° N and S (Europe:

45° - 60° N); Global Position: eastern parts of the United States and southern

Canada, northern China, Korea, Japan, central and Eastern Europe.

Group 3: High Latitude Climates

Polar and arctic air masses dominate these regions. Canada and Siberia are

two air-mass sources, which fall into this group. A southern hemisphere counterpart

to these continental centers does not exist. Air masses of arctic origin meet polar

continental air masses along the 60th and 70th parallels.

Boreal forest Climate (Dfc) — Taiga biome: This is a continental climate with

long, very cold winters, and short, cool summers. This climate is found in the polar

air mass region. Very cold air masses from the arctic often move in. The temperature

range is larger than any other climate. Precipitation increases during summer months,

although annual precipitation is still small. Much of the boreal forest climate is

considered humid. However, large areas in western Canada and Siberia receive very

little precipitation and fall into the sub-humid or semi-arid climate type. Temperature

Range: 41 °C (74 °F), lows; -25 °C (-14 °F), highs; 16 °C (60 °F); Average Annual

Precipitation: 31 cm (12 in); Latitude Range: 50° - 70° N and S; Global Position:

central and western Alaska, Canada, from the Yukon Territory to Labrador, Eurasia,

from northern Europe across all of Siberia to the Pacific Ocean.

Tundra Climate (E) — Tundra biome: The tundra climate is found along arctic

coastal areas. Polar and arctic air masses dominate the tundra climate. The winter

season is long and severe. A short, mild season exists, but not a true summer

season. Moderating ocean winds keep the temperatures from being as severe as

interior regions: Temperature Range: -22 °C to 6 °C (-10 °F to 41 °F); Average

Annual Precipitation: 20 cm (8 in); Latitude Range: 60° - 75° N; Global Position:

arctic zone of North America, Hudson Bay region, Greenland coast; northern Siberia

bordering the Arctic Ocean.


Highland Climate (H) — Alpine biome: Highland climates are cool to cold, found

in mountains and high plateaus. Climates change rapidly on mountains, becoming

colder the higher the altitude gets. The climate of a highland area is closely

related to the climate of the surrounding biome. The highlands have the same

seasons and wet and dry periods as the biome they are in. Mountain climates are

very important to mid-latitude biomes. They work as water storage areas. Snow is

kept back until spring and summer when it is released slowly as water through

melting. Temperature Range: -18 °C to 10 °C (-2 °F to 50°F); Average Annual

Precipitation: 23 cm (9 in); Latitude Range: found all over the world; Global Position:

Rocky Mountain Range in North America, the Andean mountain range in South

America, the Alps in Europe, Mt. Kilimanjaro in Africa, the Himalayans in India,

Mt. Fuji in Japan.

4.2.3 Cyclone Disturbances

The terms “hurricane” and “typhoon” are regionally specific names for a

strong “tropical cyclone”. A tropical cyclone is the generic term for a non-frontal

synoptic scale low-pressure system over tropical or sub-tropical waters with organized

convection (i.e. thunderstorm activity) and definite cyclonic surface wind circulation.

Figure 4b presents the primary storm tracks. Tropical cyclones with maximum

sustained surface winds of less than 17 m/s (34 kt, 39 mph) are called “Tropical

Depressions”. Once the tropical cyclone reaches winds of at least 17 m/s (34 kt,

39 mph) they are typically called a “tropical storm” and assigned a name. If winds

reach 33 m/s (64 kt, 74 mph)), then they are called “hurricane” (the North Atlantic

Ocean, the Northeast Pacific Ocean east of the dateline, or the South Pacific

Ocean east of 160E) or “typhoon” (the Northwest Pacific Ocean west of the dateline)

or “severe tropical cyclone” (the Southwest Pacific Ocean west of 160 0E or

Southeast Indian Ocean east of 90 0E) or “severe cyclonic storm” (the North Indian

Ocean) or “tropical cyclone” (the Southwest Indian Ocean).

“Super-typhoon” is a term utilized by the U.S. Joint Typhoon Warning Center

for typhoons that reach maximum sustained 1-minute surface winds of at least 65

m/s (130 kt, 150 mph). This is the equivalent of a strong category 4 or 5 hurricane

in the Atlantic basin or a category severe tropical cyclone in the Australian basin.

“Major hurricane” is a term utilized by the U.S. National Hurricane Center

for hurricanes that reach maximum sustained 1-minute surface winds of at least

50 m/s (96 kt, 111 mph). This is the equivalent of category 3, 4 & 5. “Intense

hurricane” is an unofficial term, but is often used in the scientific literature. It is

the same as “major hurricane”.

It has been recognized since at least the 1930s that lower tropospheric

(from the Ocean surface to about 5 km [3 mi] with a maximum at 3 km [2 mi])

westward traveling disturbances often serve as the “seedling” circulations for a

large proportion of tropical cyclones over the North Atlantic Ocean. These

disturbances, now known as African easterly waves, had their origins over North

Africa. The jet arises as a result of the reversed lower-tropospheric temperature

gradient over western and central North Africa due to extremely warm temperatures


over the Saharan Desert in contrast with substantially cooler temperatures along

the Gulf of Guinea coast.

The waves move generally toward the west in the lower tropospheric trade

wind flow across the Atlantic Ocean. They are first seen usually in April or May

and continue until October or November. The waves have a period of about 3 or 4

days and a wavelength of 2000 to 2500 km [1200 to 1500 mi], typically. One

should keep in mind that the “waves” can be more correctly thought of as the

convectively active troughs along an extended wave train. On average, about 60

waves are generated over North Africa each year, but it appears that the number

that is formed has no relationship to how much tropical cyclone activity there is

over the Atlantic each year. While only about 60% of the Atlantic tropical storms

and minor hurricanes category 1 & 2 originate from easterly waves, nearly 85% of

the intense (or major) hurricanes have their origins as easterly waves. It is suggested,

though, that nearly all of the tropical cyclones that occur in the Eastern Pacific

Ocean can also be traced back to Africa.

A tropical cyclone is a discrete tropical weather system of apparently

organized convection - generally 200 to 600 km (100 to 300 nmi) in diameter -

originating in the tropics or subtropics, having a non-frontal migratory character,

and maintaining its identity for 24 hours or more. It may or may not be associated

with a detectable perturbation of the wind field. Disturbances associated with

perturbations in the wind field and progressing through the tropics from east to

west are also known as easterly waves.

Tropical Depression: A tropical cyclone in which the maximum sustained wind

speed is 33 kt (38 mph, 17 m/s). Depressions have a closed circulation.

Tropical Storm: A tropical cyclone in which the maximum sustained wind speed

ranges from 34 kt (39 mph, 17.5 m/s) to 63 kt (73 mph, 32.5 m/s). The convection

in tropical storms is usually more concentrated near the center with outer rainfall

organizing into distinct bands.

Hurricane: When winds in a tropical cyclone equal or exceed 64 kt (74 mph, 33 m/

s) it is called a hurricane (in the Atlantic and eastern and central Pacific Oceans).

Hurricanes are further designated by categories. Hurricanes in categories 3, 4, 5

are known as Major Hurricanes or Intense Hurricanes. The wind speed mentioned

here are for those measured or estimated as the top speed sustained for one

minute at 10 meters above the surface. Peak gusts would be on the order of 10-

25% higher.

A sub-tropical cyclone: A sub-tropical cyclone is a low-pressure system existing in

the tropical or subtropical latitudes (anywhere from the equator to about 50°N)

that has characteristics of both tropical cyclones and mid-latitude (or extra-tropical)

cyclones. Therefore, many of these cyclones exist in a weak to moderate horizontal

temperature gradient region (like mid-latitude cyclones), but also receive much of

their energy from convective clouds (like tropical cyclones). Often, these storms

have a radius of maximum winds, which is farther out (on the order of 100-200 km


[60-125 miles] from the center) than what is observed for purely “tropical” systems.

Additionally, the maximum sustained wind for sub-tropical cyclones have not been

observed to be stronger than about 33 m/s (64 kts, 74 mph)).

Many times these subtropical storms transform into true tropical cyclones.

A recent example is the Atlantic basin’s Hurricane Florence in November 1994,

which began as a subtropical cyclone before becoming fully tropical. Note there

has been at least one occurrence of tropical cyclones transforming into a subtropical

storm (e.g. Atlantic basin storm 8 in 1973). Subtropical cyclones in the Atlantic

basin are classified by the maximum sustained surface winds: less than 18 m/s (34

kts, 39 mph) - “subtropical depression”, greater than or equal to 18 m/s (34 kts, 39

mph) - “subtropical storm”. Prior to 2002 subtropical storms were not given names,

but issued forecasts and warnings similar to those for tropical cyclones. Now they

are given names from the tropical cyclone list.

Extra-tropical Cyclones: An extra-tropical cyclone is a storm system that primarily

gets its energy from the horizontal temperature contrasts that exist in the

atmosphere. Extra-tropical cyclones (also known as mid-latitude or baroclinic storms)

are low-pressure systems with associated cold fronts, warm fronts, and occluded

fronts. Tropical cyclones, in contrast, typically have little to no temperature

differences across the storm at the surface and their winds are derived from the

release of energy due to cloud/rain formation from the warm moist air of the

tropics.

Structurally, tropical cyclones have their strongest winds near the Earth’s

surface, while extra-tropical cyclones have their strongest winds near the tropopause.

These differences are due to the tropical cyclone being “warm-core” in the

troposphere (below the tropopause) and the extra-tropical cyclone being “warm-

core” in the stratosphere (above the tropopause) and “cold-core” in the troposphere.

“Warm-core” refers to being relatively warmer than the environment at the same

pressure surface (“pressure surfaces” are simply another way to measure height or

altitude). Often, a tropical cyclone will transform into an extra-tropical cyclone as

it re-curves pole ward and to the East. Occasionally, an extra-tropical cyclone will

lose its frontal features, develop convection near the center of the storm and

transform into a full-fledged tropical cyclone. Such a process is most common in

the North Atlantic and Northwest Pacific basins. The transformation of tropical

cyclone into an extra-tropical cyclone (and vice versa) is currently one of the most

challenging forecast problems.

The rule used to be that if the tropical storm or hurricane moved into a

different basin, then it was renamed to whatever name was next on the list for the

area. The last time that this occurred was in July 1996 when Atlantic basin Tropical

Storm Cesar moved across Central America and was renamed Northeast Pacific

basin Tropical Storm Douglas. The last time that a Northeast Pacific system moved

into the Atlantic basin was in June 1989 when Cosme became Allison. However,

these rules have now changed at the National Hurricane Center and if the system

remains a tropical cyclone as it moves across Central America, then it will keep the


original name. Only if the tropical cyclone dissipates with just a tropical disturbance

remaining, will give the system a new name assuming it becomes a tropical cyclone

once again in its new basin.

The reason is that the Earth’s rotation sets up an apparent force (called the

Coriolis force) that pulls the winds to the right in the Northern Hemisphere (and to

the left in the Southern Hemisphere). So when a low pressure starts to form North

of the equator, the surface winds will flow inward trying to fill in the low and will

be deflected to the right and a counter-clockwise rotation will be initiated. The

opposite (a deflection to the left and a clockwise rotation) will occur South of the

equator.

The Atlantic hurricane season is officially from 1 June to 30 November.

There is nothing magical in these dates, and hurricanes have occurred outside of

these six months, but these dates were selected to encompass over 97% of tropical

activity. June 1st has been the traditional start of the Atlantic hurricane season for

decades. However, the end date has been slowly shifted outward, from October

31st to November 15th until its current date of November 30th. The Atlantic basin

shows a very peaked season from August through October, with 78% of the

tropical storm days, 87% of the minor (Saffir-Simpson Scale categories 1 and 2 -

hurricane days, and 96% of the major (Saffir-Simpson Scale categories 3, 4 and 5)

hurricane days occurring then). Maximum activity is in early to mid September.

Once in a few years there may be a tropical cyclone occurring “out of season” -

primarily in May or December.

The Northeast Pacific basin has a broader peak with activity beginning in

late May or early June and going until late October or early November with a peak

in storminess in late August/early September. NHC’s official dates for this basin

are from May 15th to November 30th.

The Northwest Pacific basin has tropical cyclones occurring all year round

regularly. There is no official definition of typhoon season for this reason. There is

a distinct minimum in February and the first half of March, and the main season

goes from July to November with a peak in late August/early September.

The North Indian basin has a double peak of activity in May and November

though tropical cyclones are seen from April to December. The severe cyclonic

storms (>33 m/s winds [76 mph]) occur almost exclusively from April to June and

late September to early December.

The Southwest Indian and Australian/Southeast Indian basins have very similar

annual cycles with tropical cyclones beginning in late October/early November,

reaching a double peak in activity - one in mid-January and one in mid-February to

early March, and then ending in May. The Australian/Southeast Indian basin February

lull in activity is a bit more pronounced than the Southwest Indian basin’s lull.

The Australian/Southwest Pacific basin begin with tropical cyclone activity

in late October/early November, reaches a single peak in late February/early March,

and then fades out in early May. Globally, September is the most active month and


May is the least active month.

El Niño/Southern Oscillation (ENSO) - During El Niño events (ENSO warm phase),

tropospheric vertical shear is increased inhibiting tropical cyclone genesis and

intensification, primarily by causing the 200 mb (12 km or 8 mi) westerly winds to

be stronger. La Nina events (ENSO cold phase) enhance activity. The changes to

the moist static stability can also contribute toward hurricane changes due to

ENSO, with a drier, more stable environment present during El Nino events.

The Australian/Southwest Pacific shows a pronounced shift back and forth

of tropical cyclone activity with fewer tropical cyclones between 145° and 165°E

and more from 165°E eastward across the South Pacific during El Niño (warm

ENSO) events. There is also a smaller tendency to have the tropical cyclones originate

a bit closer to the equator. The opposite would be true in La Niña (cold ENSO)

events.

The western portion of the Northeast Pacific basin (140°W to the dateline)

has been suggested to experience more tropical cyclone genesis during the El Niño

year and more tropical cyclones tracking into the sub-region in the year following

an El Niño, but this has not been completely documented yet.

The Northwest Pacific basin, similar to the Australian/Southwest Pacific

basin, experiences a change in location of tropical cyclones without a total change

in frequency. West of 160°E observed reduced numbers of tropical cyclone genesis

with increased formations from 160E to the dateline during El Niño events. The

opposite occurred during La Niña events. Again there is also the tendency for the

tropical cyclones to also form closer to the equator during El Niño events than

average.

The eastern portion of the Northeast Pacific, the Southwest Indian, the

Southeast Indian/Australian, and the North Indian basins have either shown little

or a conflicting ENSO relationship and/or have not been looked at yet in sufficient

detail.

Tornadoes: While both tropical cyclones and tornadoes are atmospheric vortices,

they have little in common. Tornadoes have diameters on the scale of 100s of

meters and are produced from a single convective storm (i.e. a thunderstorm or

cumulonimbus). A tropical cyclone, however, has a diameter on the scale of 100s

of kilometers and is comprised of several to dozens of convective storms.

Additionally, while tornadoes require substantial vertical shear of the horizontal

winds (i.e. change of wind speed and/or direction with height) to provide ideal

conditions for tornado genesis, tropical cyclones require very low values (less than

10 m/s [20 kt, 23 mph]) of tropospheric vertical shear in order to form and grow.

These vertical shear values are indicative of the horizontal temperature fields for

each phenomenon: tornadoes are produced in regions of large temperature gradient,

while tropical cyclones are generated in regions of near zero horizontal temperature

gradient. Tornadoes are primarily over-land phenomena as solar heating of the land

surface usually contributes toward the development of the thunderstorm that spawns

the vortex (though over-water tornadoes have occurred). In contrast, tropical cyclones


are purely oceanic phenomena - they die out over-land due to a loss of a moisture

source. Lastly, tropical cyclones have a lifetime that is measured in days, while

tornadoes typically last on the scale of minutes.

An interesting side note is that tropical cyclones at landfall often provide

the conditions necessary for tornado formation. As the tropical cyclone makes

landfall and begins decaying, the winds at the surface die off quicker than the

winds at, say, 850 mb. This sets up a fairly strong vertical wind shear that allows

for the development of tornadoes, especially on the tropical cyclone’s right side

(with respect to the forward motion of the tropical cyclone). For the southern

hemisphere, this would be a concern on the tropical cyclone’s left side - due to the

reverse spin of southern hemisphere storms.

4.2.4 Monsoons

Indian Monsoons: Book of Das (1968) presents the monsoons in India. At the

Equator, the area near India is unique in that dominant or frequent westerly winds

occur at the surface almost constantly throughout the year; the surface easterlies

reach only to 20º N in February, and even then they have a very strong northerly

component. They soon retreat northward, and drastic changes take place in the

upper-air circulation. This is a time of transition between the end of one monsoon

and the beginning of the next. Late in March the high-sun season reaches the

Equator and moves farther north. With it go atmospheric instability, convectional

(rising, turbulent) clouds, and rain. The westerly subtropical jet stream still controls

the flow of air across northern India and the surface winds are north-easterlies. As

the high-sun season moves northward during April, India becomes particularly

prone to rapid heating because the highlands to the north protect it from any

incursions of cold air. In May the southwesterly monsoon is well established over

Sri Lanka. There are three distinct regions of relative upper tropospheric warmth—

namely (1) above the southern Bay of Bengal, (2) above the highlands of Tibet, and

(3) across the still, dry trunks of the peninsulas. The relatively warm area above the

southern Bay of Bengal occurs mostly at the 500-100 mb level. It does not appear

at a lower level and is probably caused by the release of condensation heat (associated

with the change from water vapour to liquid water) at the top of towering

cumulonimbus clouds along the advancing inter-tropical convergence.

In May the dry surface of Tibet (above 4,000 m) absorbs and radiates heat

that is readily transmitted to the air immediately above. At about 6,000 m an anti-

cyclonic cell arises, causing a strong easterly flow in the upper troposphere above

northern India. The subtropical jet stream suddenly changes its course to the

North of the anti-cyclonic ridge and the highlands, though it may occasionally

reappear southward of them for very brief periods. This change of the upper

tropospheric circulation above northern India from westerly jet to easterly flow

coincides with a reversal of the vertical temperature and pressure gradients between

600 and 300 mb. On many occasions the easterly aloft assumes jet force. It

anticipates by a few days the “burst,” or onset, of the surface southwesterly

monsoon some 1,500 km farther south, with a definite sequential relationship,


although the exact cause is not known. Because of India’s inverted triangular

shape, the land is heated progressively as the Sun moves northward. This accelerated

spread of heating, combined with the general direction of heat being transported

by winds, results in a greater initial monsoon activity over the Arabian Sea (at late

spring time), where a real frontal situation often occurs, than over the Bay of

Bengal. The relative humidity of coastal districts in the Indian region rises above

70% and some rain occurs. Above the heated land the air below 1,500 m becomes

unstable, but it is held down by the overriding easterly flow. This does not prevent

frequent thunderstorms in late May.

During June the easterly jet becomes firmly established at 150 to 100 mb. It

reaches its greatest speed at its normal position to the South of the anti-cyclonic

ridge, at about 15º N from China through India.

In Arabia, it decelerates and descends to the middle troposphere (3,000 m).

A stratospheric belt of very cold air, analogous to the one normally found above

the ITCZ near the Equator, occurs above the anti-cyclonic ridge, across southern

Asia at 30º-40º N and above the 6,000-m (500 mb) level. These upper air features

that arise so far away from the Equator are associated with the surface monsoon

and are absent when there is no monsoon flow. The position of the easterly jet

controls the location of monsoon rains, which occur ahead and to the left of the

strongest winds and behind them to the right. The surface flow, however, is a

strong, southwesterly, humid, and unstable wind that brings humidities of more

than 80% and heavy, squally showers that are the “burst” of the monsoon. The

overall pattern of the advance follows a frontal alignment, but local episodes may

differ considerably. The amount of rain is variable from year to year and place to

place. Most spectacular clouds and rain occur against the Western Ghats, where

the early monsoon air-stream piles up against the steep slopes, then recedes, and

piles up again to a greater height. Each time it pushes thicker clouds upward until

wind and clouds roll over the barrier and, after a few brief spells of absorption by

the dry inland air, cascade toward the interior. The windward slopes receive from

2,000 to 5,000 mm of rain in the monsoon season. Various factors, and especially

topography, combine to make up a complex regional pattern. Oceanic air flowing

toward India below 6,000 m is deflected in accordance with the Coriolis effect.

The converging, moist oncoming stream becomes unstable over the hot land and

is subject to convectional turmoil. Towering cumulonimbus clouds rise thousands

of m, producing violent thunderstorms and releasing latent heat in the surrounding

air. As a result, the upper tropospheric warm belt migrates northwestward from

the ocean to the land. The main body of air above 9,000 m maintains a strong

easterly flow.

Later, in June and July, the monsoon is strong and well established to a

height of 6,000 m (less in the far North); with occasional thickening to 9,000 m.

Weather conditions are cloudy, warm, and moist all over India. Rainfall varies between

400 and 500 mm, but topography introduces some extraordinary differences. On

the southern slopes of the Khasi Hills at only 1,300 m, where the moist airstreams

are lifted and overturned, Cherrapunji has an average rainfall of 2,730 mm in July,


with record totals of 897 mm in 24 hours in July 1915, more than 9,000 mm in

July 1861, and 16,305 mm in the monsoon season of 1899. Over the Ganges

Valley the monsoon, deflected by the Himalayan barrier, becomes a southeasterly

air-flow. By then the upper tropospheric belt of warmth from condensation has

moved above northern India, with an oblique bias. The lowest pressures prevail at

the surface.

It is mainly in July and August that waves of low pressure appear in the

body of monsoon air. Fully developed depressions appear once or twice a month.

They travel from east to west more or less concurrently with high-level easterly

waves and bursts of speed in the easterly jet, causing local strengthening of the

low-level monsoon flow. The rainfall consequently increases and is much more

evenly distributed than it was in June. Some of the deeper depressions become

tropical cyclones before they reach the land, and these bring torrential rains and

disastrous floods.

A totally different development arises when the easterly jet moves farther

north than usual because the monsoon wind rising over the southern slopes of the

Himalayas brings heavy rains and local floods. The weather over the central and

southern districts, however, becomes suddenly drier and remains so for as long as

the abnormal shift lasts. The opposite shift is also possible, with mid-latitude

upper air flowing along the south face of the Himalayas and bringing drought to

the northern districts. Such dry spells are known as “breaks” of the monsoon.

Those affecting the south are similar to those experienced on the Guinea coast

during extreme northward shifts of the wind belts (as later discussed), whereas

those affecting the north are due to an interaction of the middle and lower latitudes.

The southwest monsoon over the lower Indus Plain is only 500 m thick and does

not hold enough moisture to bring rain. On the other hand, the upper tropospheric

easterlies become stronger and constitute a true easterly jet stream. Western

Pakistan, Iran, and Arabia remain dry (probably because of divergence in this jet)

and thus become the new source of surface heat.

By August the intensity and duration of sunshine have decreased,

temperatures begin to fall, and the surge of southwesterly air diminishes

spasmodically almost to a standstill in the northwest. Cherrapunji still receives

over 2,000 mm of rainfall at this time, however. In September dry, cool, northerly

air begins to circle the west side of the highlands and spread over northwestern

India. The easterly jet weakens and the upper tropospheric easterlies move much

farther south. Because the moist south-westerlies at lower levels are much weaker

and variable, they are soon pushed back. The rainfall becomes extremely variable

over most of the region, but showers are still frequent in the southeastern areas

and over the Bay of Bengal.

By early October variable winds are very frequent everywhere. At the end of

the month the entire Indian region is covered by northerly air and the winter

monsoon takes shape. The surface flow is deflected by the Coriolis force and

becomes a northeasterly flow. This causes an October-December rainy season for


the extreme southeast of the Deccan (including the Tamil Nadu coast) and eastern

Sri Lanka, which cannot be explained by topography alone because it extends well

out over the sea. Tropical depressions and cyclones are important contributing

factors.

Most of India thus begins a sunny, dry, and dusty season. The driest period

comes in November in the Punjab; December in Central India, Bengal, and Assam;

January in the northern Deccan; and February in the southern Deccan. Conversely,

the western slopes of the Karakoram and Himalayas are then reached by the mid-

latitude frontal depressions that come from the Atlantic and the Mediterranean.

The winter rains they receive, moderate as they are, place them clearly outside the

monsoon realm.

Because crops and water supplies depend entirely on monsoon rains, it

became imperative that quantitative, long-range weather forecasts be available. For

a forecast to be released at the beginning of June, it is necessary to use, in April,

South American pressure data and Indian upper-wind conditions (positive

correlation) and, in May, rainfall in Zimbabwe and Java and easterly winds above

Calcutta (negative correlation).

The Malaysian-Australian Monsoon: Southeast Asia and northern Australia are

combined in one monsoon system that differs from others because of the peculiar

and somewhat symmetrical distribution of landmasses on both sides of the Equator.

In this respect, the northwest monsoon of Australia is unique. The substantial

masses of water between Asia and Australia have a moderating effect on tropospheric

temperatures, weakening the summer monsoon. The many islands (e.g., Philippines

and Indonesia) provide an infinite variety of topographic effects. Typhoons that

develop within the monsoon air bring additional complications.

It would be possible to exclude North China, Korea, and Japan from the

monsoon domain because their seasonal rhythm follows the normal mid-latitude

pattern—a predominant outflow of cold continental air in winter, and frontal

depressions and rain alternating with fine, dry anti-cyclonic weather in the warm

season. On the other hand, the seasonal reversal of wind direction in this area is

almost as persistent as that in India. The winter winds are much stronger because

of the relative proximity of the Siberian anticyclone. The tropical ridge of high

pressure is the natural boundary between these non-monsoonal areas and the

monsoon lands farther south.

The northern limit of the typical monsoon may be set at about latitude 25º

N. Farther North, the summer monsoon is not strong enough to overcome the

effect of the traveling anticyclones normally typical of the subtropics. As a result,

monsoon rains occur in June and also in late August and September, separated by

a mild anti-cyclonic drought in July. In South China and the Philippines the trade

winds prevail in the October-April (winter) period, strengthened by the regional,

often gusty, outflow of air from the stationary Siberian anticyclone. Their

disappearance and replacement by opposite (southwesterly) winds in the May-

September (summer) period is the essence of the monsoon. In any case, these


monsoon streams are quite shallow, about 1,500 m in winter and 2,000 m in

summer. They bring rain only when subject to considerable cooling, as happens to

the windward anywhere on the steep slopes of the Philippines and Taiwan. On the

larger islands there are contrasting effects, the slopes facing west receiving most

of the rain from May to October and a drought from December to April, whereas

the slopes facing east receive orographic rains (those produced when moist air is

forced to rise by topography) from September to April and mainly convectional

rains from May to October.

In Vietnam and Thailand the summer monsoon is more strongly developed

because of the wider expanses of overheated land. The southwesterly stream flows

from May to October, reaching a thickness of four to five km; it brings plentiful

but not extraordinary rainfall. November to February is the cool, dry season, and

March to April the hot, dry one; in the far south the coolness is but relative. Along

the east coast and on the eastward slopes more rain is brought by the winter

monsoon. In the summer, somewhere between Thailand and Kampuchea in the

interior, there may be a faint line of convergence between the southwesterly Indian-

Burmese monsoon and the southeasterly

Malaysian Monsoon: Winds are weak over Indonesia because of the expanses of

water and the low latitude, but their seasonal reversal is definite. From April to

October the Australian southeasterly air flows, whereas north of the Equator it

becomes a southwesterly. It generally maintains its dryness over the islands closer

to Australia, but farther north it carries increasing amounts of moisture. The

northeasterly flow from Asia, which becomes northwesterly south of the Equator,

is laden with moisture when it reaches Indonesia, bringing cloudy and rainy weather

between November and May. The wettest months are December in most of Sumatra

and January elsewhere, but rainfall patterns are highly localized. In Java, for instance,

at sea level alone there are two major regions, an “equatorial” west with no dry

season and a “monsoon” east with extreme drought in August and September.

Because of its relatively small size and compact shape, Australia shows

relatively simple monsoon patterns. The north shore is subject to a clear-cut wind

reversal between summer (November-April, north-westerly) and winter (May-

September, southeasterly), but with two definite limitations: first, the northwesterly,

rain-bearing monsoon wind is often held offshore and is most likely to override the

land to any depth during January and February; and second, even in summer there

often are prolonged spells of southeasterly trade winds issuing from traveling

anticyclones, separating the brief monsoon incursions. The Australian summer

monsoon is thus typical in direction and weather type but quite imperfect in

frequency and persistence. Its thickness is usually less than 1,500 m over the sea

and 2,000-2,500 m over the land.

Much less typical are the marginal monsoon manifestations. On the northwest

coast there frequently is a northwesterly airflow in the summer (December-March),

as opposed to the winter south-easterlies, but this stream is very shallow and does

not bring any rain—i.e. its weather is not monsoon even though its direction is so.


On the northeast coast the onshore air is humid and brings rain, but its direction is

only partly modified in summer. It comes in mostly as a northeasterly, while at

other times it is mostly southeasterly.

4.3 Indian Climate

It is clear from the above presentations, the climate of India comprises a

wide range of weather conditions across a large geographic scale and varied

topography, making generalizations difficult. Analyzed according to the Koppen

System of classification, India hosts six major climatic subtypes [Figure 4c], ranging

from desert in the west, to alpine tundra and glaciers in the north, to humid

tropical regions supporting rainforests in the southwest and the island territories.

Many regions have starkly different microclimates. The nation has four seasons:

winter (January and February), summer (March to May), a monsoon (rainy) season

(June to September), and a post-monsoon period (October to December).

India’s unique geography and geology strongly influence its climate; this is

particularly true of the “Himalayas” in the North and the “Thar Desert” in the

Northwest. The Himalayas act as a barrier to the frigid katabatic winds flowing

down from Central Asia. Thus, North India is kept warm or only mildly cold during

winter; in summer, the same phenomenon makes India relatively hot. Although the

Tropic of Cancer — the boundary between the tropics and subtropics—passes

through the middle of India, the whole country is considered to be tropical. As in

much of the tropics, monsoon and other weather conditions in India are unstable:

major droughts, floods, cyclones and other natural disasters are sporadic, but have

killed or displaced millions. Climatic diversity in India makes the analysis of these

issues complex. However, the Indian climate is modified by topographical patterns

prevailing over different parts of India.

4.3.1 Types of Climates

India is home to an extraordinary variety of climatic regions, ranging from

tropical in the south to temperate and alpine in the Himalayan North, where

elevated regions receive sustained winter snowfall. The nation’s climate is strongly

influenced by the Himalayas and the Thar Desert. The Himalayas, along with the

Hindu Kush mountains in Pakistan, prevent cold Central Asian katabatic winds

from blowing in, keeping the bulk of the Indian subcontinent warmer than most

locations at similar latitudes. Simultaneously, the Thar Desert plays a role in

attracting moisture-laden Southwest Summer Monsoon winds that, between June

and October, provide the majority of India’s rainfall. Four major climatic groupings

predominate, into which fall seven climatic zones that are defined on the basis of

such traits as temperature and precipitation. Groupings are assigned codes according

to the Köppen climate classification system [Figure 4c].

Tropical Wet: A tropical rainy climate covers regions experiencing persistent warm

or high temperatures, which normally do not fall below 18 oC (64 oF). India hosts

two climatic subtypes that fall under this group. The most humid is the tropical

wet monsoon climate that covers a strip of southwestern lowlands abutting the


Malabar Coast, the Western Ghats, and southern Assam. India’s two island

territories, Lakshadweep and the Andaman and Nicobar Islands, are also subject to

this climate. Characterized by moderate to high year-round temperatures, even in

the foothills, its rainfall is seasonal but heavy—typically above 2,000 mm (79 in)

per year. Most rainfall occurs between May and November; this is adequate for the

maintenance of lush forests and other vegetation throughout the remainder of the

year. December to March is the driest months, when days with precipitation are

rare. The heavy monsoon rains are responsible for the extremely biodiverse tropical

wet forests of these regions. In India, a tropical wet and dry climate is more

common. Significantly drier than tropical wet zones, it prevails over most of inland

peninsular India except for a semi-arid rain shadow east of the Western Ghats.

Winter and early summer are long, dry periods with temperatures averaging above

18 °C (64 °F). Summer is exceptionally hot; temperatures in low-lying areas may

exceed 50 °C (122 °F) during May, leading to heat waves that can each kill hundreds

of Indians. The rainy season lasts from June to September; annual rainfall averages

between 750–1500 mm (30–59 in) across the region. Once the dry northeast

monsoon begins in September, most precipitation in India falls on Tamil Nadu,

leaving other states comparatively dry.

Tropical Dry: A tropical arid and semi-arid climate dominates regions where the

rate of moisture loss through evapotranspiration exceeds that from precipitation;

it is subdivided into three climatic subtypes. The first, a tropical semi-arid steppe

climate, predominates over a long stretch of land south of Tropic of Cancer and

east of the Western Ghats and the Cardamom Hills. The region, which includes

Karnataka, inland Tamil Nadu, western Andhra Pradesh, and central Maharashtra,

gets between 400–750 mm (16–30 in) annually. It is drought-prone, as it tends to

have less reliable rainfall due to sporadic lateness or failure of the southwest

monsoon. North of the Krishna River, the summer monsoon is responsible for most

rainfall; to the south, significant post-monsoon rainfall also occurs in October and

November. In December, the coldest month, temperatures still average around 20–

24 °C (68–75 °F). The months between March to May are hot and dry; mean

monthly temperatures hover around 32 °C, with 320 mm (13 in) precipitation.

Hence, without artificial irrigation, this region is not suitable for permanent

agriculture. The Ran of Kutch, a vast salt marsh south of the Thar Desert in Gujarat.

During the monsoon season, the region fills with standing waters.

Most of western Rajasthan experiences an arid climatic regime. Cloudburst

is responsible for virtually all of the region’s annual precipitation, which totals less

than 300 mm (12 in). Such bursts happen when monsoon winds sweep into the

region during July, August, and September. Such rainfall is highly erratic; regions

experiencing rainfall one year may not see precipitation for the next couple of

years or so. Atmospheric moisture is largely prevented from precipitating due to

continuous downdrafts and other factors. The summer months of May and June

are exceptionally hot; mean monthly temperatures in the region hover around

35 °C (95 °F), with daily maxima occasionally topping 50 °C (122 °F). During

winters, temperatures in some areas can drop below freezing due to waves of cold


air from Central Asia. There is a large diurnal range of about 14 °C (57 °F) during

summer; this widens by several degrees during winter.

East of the Thar Desert, the region running from Punjab and Haryana to

Kathiawar experiences a tropical and sub-tropical steppe climate. The zone, a

transitional climatic region separating tropical desert from humid sub-tropical

savanna and forests, experiences temperatures that are less extreme than those of

the desert. Average annual rainfall is 30–65 cm (12-26 in), but is very unreliable;

as in much of the rest of India, the southwest monsoon accounts for most

precipitation. Daily summer temperature maxima rise to around 40 °C (104 °F).

The resulting natural vegetation typically comprises short, coarse grasses.

Subtropical Humid: Most of Northeast India and much of North India are subject

to a humid sub-tropical climate. Though they experience hot summers, temperatures

during the coldest months may fall as low as 0 °C (32 °F). Due to ample monsoon

rains, India has only one subtype of this climate, Cfa (under the Köppen system).

In most of this region, there is very little precipitation during the winter, owing to

powerful anticyclonic and katabatic (downward-flowing) winds from Central Asia.

Due to the region’s proximity to the Himalayas, it experiences elevated prevailing

wind speeds, again from the influence of Central Asian katabatic movements.

Humid subtropical regions are subject to pronounced dry winters. Winter rainfall—

and occasionally snowfall—is associated with large storm systems such as

“Nor’westers” and “Western Disturbances”; the latter are steered by westerlies

towards the Himalayas. Most summer rainfall occurs during powerful thunderstorms

associated with the southwest summer monsoon; occasional tropical cyclones

also contribute. Annual rainfall ranges from less than 1,000 mm (39 in) in the west

to over 2,500 mm (98 in) in parts of the northeast. As most of this region is far

from the ocean, the wide temperature swings more characteristic of a continental

climate predominate; the swings are wider than in those in tropical wet regions,

ranging from 24 °C (75 °F) in north-central India to 27 °C (81 °F) in the east.

Montane: Pangone Lake in Ladakh, an arid montane region lying deep within the

Himalayas. India’s northernmost fringes are subject to a montane, or alpine, climate.

In the Himalayas, the rate at which an air mass’s temperature falls per km (3,281 ft)

of altitude gained (the adiabatic lapse rate) is 5.1 °C/km. In terms of environmental

lapse rate, ambient temperatures fall by 0.6 °C (1.1 °F) for every 100 m (328 ft)

rise in altitude. Thus, climates ranging from nearly tropical in the foothills to

tundra above the snow line can coexist within several dozen miles of each other.

Sharp temperature contrasts between sunny and shady slopes, high diurnal

temperature variability, temperature inversions, and altitude-dependent variability

in rainfall are also common. The northern side of the western Himalayas, also

known as the trans-Himalayan belt, is a region of barren, arid, frigid, and wind-

blown wastelands. Most precipitation occurs as snowfall during the late winter

and spring months. Areas south of the Himalayas are largely protected from cold

winter winds coming in from the Asian interior. The leeward side (northern face)

of the mountains receives less rain while the southern slopes, well exposed to the

monsoon, get heavy rainfall. Areas situated at elevations of 1,070–2,290 m (3,510–


7,510 ft) receive the heaviest rainfall, which decreases rapidly at elevations above

2,290 m (7,513 ft). The Himalayas experience their heaviest snowfall between

December and February and at elevations above 1,500 m (4,921 ft). Snowfall

increases with elevation by up to several dozen mm per 100 m (~2 in; 330 ft)

increase. Elevations above 5,000 m (16,404 ft) never experience rain; all precipitation

falls as snow.

4.3.2 Seasons

The India Meteorological Department (IMD) designates four official seasons:

Winter season, occurring between January and March. The year’s coldest months

are December and January, when temperatures average around 10–15 °C (50–

59 °F) in the northwest; temperatures rise as one proceeds towards the equator,

peaking around 20–25 °C (68–77 °F) in mainland India’s southeast. Summer or

pre-monsoon season, lasting from March to June (April to July in northwestern

India). In western and southern regions, the hottest month is April; for northern

regions, May is the hottest month. Temperatures average around 32–40 °C (90–

104 °F) in most of the interior. June to September is the Monsoon or rainy season,

which is dominated by the humid southwest summer monsoon that slowly sweeps

across the country beginning in late May or early June. Monsoon rains begin

[Figure 4d] to recede from North India at the beginning of October. October to

December is the Post-monsoon season, during which period the South India typically

receives more precipitation. Monsoon rains begin to recede from North India at

the beginning of October. In northwestern India, October and November are usually

cloudless. Parts of the country experience the dry northeast monsoon. The Himalayan

states, being more temperate, experience an additional two seasons: autumn and

spring. Traditionally, Indians note six seasons, each about two months long. These

are the spring, summer, and monsoon season, early autumn, late autumn, and

winter.

Winter: Once the monsoons subside, average temperatures gradually fall across

India. As the Sun’s vertical rays move south of the equator, most of the country

experiences moderately cool weather; temperatures change by about 0.6 °C

(1.35 °F) per degree of latitude. December and January are the coldest months,

with mean temperatures of 10–15 °C (50–59 °F) in Indian Himalayas. Mean

temperatures are higher in the east and south, where they reach 20–25 °C (68–

77 °F). In northwestern India, virtually cloudless conditions prevail in October and

November, resulting in wide diurnal temperature swings; as in much of the Deccan

Plateau, they range between 16–20 °C (61–68 °F).

However, from March to May, “western disturbances” bring heavy bursts of

rain and snow. These extra-tropical low-pressure systems originate in the eastern

Mediterranean Sea. They are carried towards India by the subtropical westerlies,

which are the prevailing winds blowing at North India’s range of latitude. Once

their passage is hindered by the Himalayas, they are unable to proceed further, and

they release significant precipitation over the southern Himalayas. The three

Himalayan states (Jammu and Kashmir in the extreme north, Himachal Pradesh,


and Uttarkhand) experience heavy snowfall; in Jammu and Kashmir, blizzards occur

regularly, disrupting travel and other activities.

The rest of North India, including the Indo-Gangetic Plain, almost never receives

snow. However, in the plains, temperatures occasionally fall below freezing, though

never for more one or two days. Winter highs in Delhi range from 16 °C (61 °F) to

21 °C (70 °F). Nighttime temperatures average 2–8 °C (36–46 °F). In the Punjab

plains, lows can fall below freezing, dropping to around -6 °C (21 °F) in Amritsar.

Frost sometimes occurs, but the hallmark of the season is the notorious fog, which

frequently disrupts daily life; fog grows thick enough to hinder visibility and disrupt

air travel 15–20 days annually. Eastern India’s climate is much milder, experiencing

moderately warm days and cool nights. Highs range from 23 °C (73 °F) in Patna to

26 °C (79 °F) in Kolkata (Calcutta); lows average from 8 °C (46 °F) in Patna to

14 °C (57 °F) in Kolkata. Frigid winds from the Himalayas can depress temperatures

near the Brahmaputra River. The two Himalayan states in the east, Sikkim and

Arunachal Pradesh, receive substantial snowfall. The extreme north of West Bengal,

centered on Darjeeling, also experiences snowfall, but only rarely.

In South India, particularly the hinterland of Maharashtra, Madhya Pradesh,

parts of Karnataka, and Andhra Pradesh, somewhat cooler weather prevails. Minimum

temperatures in western Maharashtra, Madhya Pradesh and Chattisgarh hover around

10 °C (50 °F); in the southern Deccan Plateau, they reach 16 °C (61 °F). Coastal

areas, especially those near the Coromandal Coast, and low-elevation interior tracts

are warm, with daily high temperatures of 30 °C (86 °F) and lows of around

21 °C (70 °F). The Western Ghats, including the Nilgiri Range, are exceptional;

there, lows can fall below freezing. This compares with a range of 12–14 °C (54–

57 °F) on the Malabar Coast; there, as is the case for other coastal areas, the

Indian Ocean exerts a strong moderating influence on weather.

Summer: Summer in northwestern India lasts from April to July, and in the rest of

the country from March to June. The temperatures in the north rise as the vertical

rays of the Sun reach the Tropic of Cancer. The hottest month for the western and

southern regions of the country is April; for most of North India, it is May.

Temperatures of 50 °C (122 °F) and higher have been recorded in parts of India

during this season In cooler regions of North India, immense pre-monsoon squall-

line thunderstorms, known locally as “Nor’westers”, commonly drop large hailstones.

Near the coast the temperature hovers around 36 °C (97 °F), and the proximity of

the sea increases the level of humidity. In southern India, the temperatures are

higher on the east coast by a few degrees compared to the west coast. By May,

most of the Indian interior experiences mean temperatures over 32 °C (90 °F),

while maximum temperatures often exceed 40 °C (104 °F). In the hot months of

April and May, western disturbances, with their cooling influence, may still arrive,

but rapidly diminish in frequency as summer progresses. Notably, a higher frequency

of such disturbances in April correlates with a delayed monsoon onset (thus

extending summer) in northwest India. In eastern India, monsoon onset dates have

been steadily advancing over the past several decades, resulting in shorter summers

there.


Altitude affects the temperature to a large extent, with higher parts of the

Deccan Plateau and other areas being relatively cooler. Hill Stations, such as

Ootacamund (“Ooty”) in the Western Ghats and Kalimpong in the eastern Himalayas,

with average maximum temperatures of around 25 °C (77 °F), offer some respite

from the heat. At lower elevations, in parts of northern and western India, a strong,

hot, and dry wind known as the Loo blows in from the west during the daytime;

with very high temperatures, in some cases up to around 45 °C (113 °F); it can

cause fatal cases of sunstroke Tornadoes may also occur, concentrated in a corridor

stretching from northeastern India towards Pakistan. They are rare, however; only

several dozen have been reported since 1835.

Monsoon: The southwest summer monsoon, a four-month period when massive

convective thunderstorms dominate India’s weather, is Earth’s most valuable wet

season. It results from the southeast trade winds originating from a high-pressure

mass centered over the southern Indian Ocean; attracted by a low-pressure region

centered over South Asia, it gives rise to surface winds that ferry humid air into

India from the southwest. These inflows ultimately result from a northward shift

of the local jet stream, which itself results from rising summer temperatures over

Tibet and the Indian subcontinent. The void left by the jet stream, which switches

from a route just south of the Himalayas to one tracking north of Tibet, then

attracts warm, humid air. The main factor behind this shift is the high summer

temperature difference between Central Asia and the Indian Ocean. This is

accompanied by a seasonal excursion of the normally equatorial ITCZ, a low-pressure

belt of highly unstable weather, northward towards India. This system intensified

to its present strength as a result of the Tibetan Plateau’s uplift, which accompanied

the Eocene-Oligocene transition event, a major episode of global cooling and

aridification, which occurred 34–49 mya.

The southwest monsoon arrives in two branches: the Bay of Bengal branch

and the Arabian sea branch. The latter extends toward a low-pressure area over the

Thar Desert and is roughly three times stronger than the Bay of Bengal branch.

The monsoon usually breaks over Indian territory by around 25 May, when it lashes

the Andaman and Nicobar Islands in the Bay of Bengal. It strikes the Indian mainland

around 1 June supplies over 80% of India’s annual rainfall. First appearing near

the Malabar Coast of Kerala [Figure 4d]. By 10 June, it reaches Mumbai; it appears

over Delhi by 2 July. The Bay of Bengal branch, which hugs the Coromandal Coast

between Cape Comorin and Orissa, swerves to the northwest. The Arabian Sea

branch moves northeast towards the Himalayas. By the first week of July, the

entire country experiences monsoon rain; on average, South India receives more

rainfall than North India. However, Northeast India receives the most precipitation.

Monsoon clouds begin retreating from North India by the end of August; it withdraws

from Mumbai by 5 October. As India further cools during September, the southwest

monsoon weakens. By the end of November, it has left the country.

Monsoon rains impact the health of the Indian economy; as Indian agriculture

employs 600 million people and composes 20% of the national GDP good monsoons

correlate with a booming economy. Weak or failed monsoons (droughts) result in


widespread agricultural losses and substantially hinder overall economic growth.

The rains reduce temperatures and replenish groundwater tables, rivers, and lakes.

Post-monsoon: During the post-monsoon months of October to December, a

different monsoon cycle, the northeast (or “retreating”) monsoon, brings dry, cool,

and dense Central Asian air masses to large parts of India. Winds spill across the

Himalayas and flow to the southwest across the country, resulting in clear, sunny

skies. Though the IMD and other sources refer to this period as a fourth (“post-

monsoon”) season, other sources designate only three seasons. Depending on

location, this period lasts from October to November, after the southwest monsoon

has peaked. Less and less precipitation falls, and vegetation begins to dry out. In

most parts of India, this period marks the transition from wet to dry seasonal

conditions. Average daily maximum temperatures range between 28 °C and 34 °C

(82–93 °F). Reddy (1978) presented weather associated with western disturbances,

which are of importance in winter both in terms of temperature and rainfall..

The northeast monsoon, which begins in September, lasts through the post-

monsoon seasons, and only ends in March, carries winds that have already lost

their moisture while crossing central Asia and the vast rain shadow region lying

north of the Himalayas. They cross India diagonally from northeast to southwest.

However, the large indentation made by the Bay of Bengal into India’s eastern

coast means that the flows are humidified before reaching Cape Comorin and rest

of Tamil Nadu, meaning that the state, and also some parts of Kerala, experience

significant precipitation in the post-monsoon and winter periods. However, parts

of West Bengal, Orissa, Andhra Pradesh, Karnataka and Northeast India also receive

minor precipitation from the northeast monsoon. Figures 4 e & 4 f presents the

rainfall and temperature patterns in India.

4.3.3 Disasters

Climate-related natural disasters cause massive losses of Indian life and

property. Droughts, flash floods, cyclones, avalanches, landslides brought on by

torrential rains, and snowstorms pose the greatest threats. Other dangers include

frequent summer dust storms, which usually track from north to south; they cause

extensive property damage in North India and deposit large amounts of dust from

arid regions. Hail is also common in parts of India, causing severe damage to

standing crops such as rice and wheat.

Floods and Landslides: In the Lower Himalaya, landslides are common. The young

age of the region’s hills result in labile rock formations, which are susceptible to

slippages. Rising population and development pressures, particularly from logging

and tourism, cause deforestation. The result, denuded hillsides, exacerbates the

severity of landslides, since tree cover impedes the downhill flow of water. Parts of

the Western Ghats also suffer from low-intensity landslides. Avalanches occur in

Kashmir, Himachal Pradesh, and Sikkim.

Floods are the most common natural disaster in India. The heavy southwest

monsoon rains cause the Brahmaputra and other rivers to distend their banks,


often flooding surrounding areas. Though they provide rice paddy farmers with a

largely dependable source of natural irrigation and fertilisation, the floods can kill

thousands and displace millions. Excess, erratic, or untimely monsoon rainfall may

also wash away or otherwise ruin crops. Almost all of India is flood-prone, and

extreme precipitation events, such as flash floods and torrential rains, have become

increasingly common in central India over the past several decades, coinciding

with rising temperatures. Mean annual precipitation totals have remained steady

due to the declining frequency of weather systems that generate moderate amount

of rain.

Cyclones: Tropical cyclones, which are severe storms spun off from the ITCZ, may

affect thousands of Indians living in coastal regions. Tropical cyclogenesis is

particularly common in the northern reaches of the Indian Ocean in and around

the Bay of Bengal. Cyclones bring with them heavy rains, Storm surges, and winds

that often cut affected areas off from relief and supplies. In the North Indian

Ocean Basin, the cyclone season runs from April to December, with peak activity

between May and November [Table 5]. Each year, an average of eight storms with

sustained wind speeds greater than 63 km/h (39 mph) form; of these, two strengthen

into true tropical cyclones, which have sustained gusts greater than 117 km/h

(73 mph). On average, a major Category 3 or higher) cyclone develops every other

year.

During summer, the Bay of Bengal is subject to intense heating, giving rise

to humid and unstable air masses that produce cyclones. Many powerful cyclones,

including the 1737 Calcutta cyclone, the 1970 Bhola cyclone, and the 1991

Bangladesh cyclone, have led to widespread devastation along parts of the eastern

coast of India and neighboring Bangladesh. Widespread death and property

destruction are reported every year in exposed coastal states such as Andhra Pradesh,

Orissa, Tamil Nadu, and West Bengal. India’s western coast, bordering the more

placid Arabian Sea, experiences cyclones only rarely; these mainly strike Gujarat

and, less frequently, Kerala.

Table 5: Monthly cyclonic disturbances in Arabian sea and

Bay of Bengal during 1891-1990

Number of disturbances recorded

Bay OF Bengal Arabian sea

Month D CS SCS T D CS SCS T

January 13 4 2 19 4 2 0 6

February 3 0 1 4 0 0 0 0

March 1 2 2 5 1 0 0 1

April 8 11 10 29 2 2 4 8

May 32 15 35 82 11 5 15 31

June 84 33 5 122 27 6 12 45

July 118 34 7 159 15 3 0 18

August 161 27 3 191 5 2 0 7


September 151 25 14 190 10 4 3 17

October 104 44 34 182 28 13 12 53

November 55 42 53 150 32 6 20 58

December 37 23 19 79 8 4 2 14

Total 767 260 185 1212 143 47 68 258

Note: D = depression, CS = cyclonic storm, SCS = severe cyclonic

storm & T = total


In terms of damage and loss of life, a super-cyclone that struck Orissa on 29

October 1999, was the worst in more than a quarter-century. With peak winds of

160 miles per hour (257 km/h), it was the equivalent of a Category 5 Hurricane

Almost two million people were left homeless; another 20 million people lives

were disrupted by the cyclone. Officially, 9,803 people died from the storm;

unofficial estimates place the death toll at over 10,000.

Droughts: Indian agriculture is heavily dependent on the monsoon as a source of

water. In some parts of India, the failure of the monsoons result in water shortages,

resulting in below-average crop yields [Figures 4g & 4h]. This is particularly true

of major drought-prone regions such as southern and eastern Maharashtra, northern

Karnataka, Andhra Pradesh, Orissa, Gujarat, and Rajasthan. In the past, droughts

have periodically led to major Indian famines. These include the Bangla famine of

1770, in which up to one third of the population in affected areas died; the 1876–

1877 famine, in which over five million people died; the 1899 famine, in which

over 4.5 million died; and the Bengal famine of 1943, in which over five million

died from starvation and famine-related illnesses.

All such episodes of severe drought correlate with El Nino- Souhern Oscillation

(ENSO) events. El Niño-related droughts have also been implicated in periodic

declines in Indian agricultural output. Nevertheless, ENSO events that have coincided

with abnormally high sea surfaces temperatures in the Indian Ocean—in one

instance during 1997 and 1998 by up to 3 °C (5 °F)—have resulted in increased


Oceanic evaporation, resulting in unusually wet weather across India. Such

anomalies have occurred during a sustained warm spell that began in the 1990s. A

contrasting phenomenon is that, instead of the usual high pressure air mass over

the southern Indian Ocean, an ENSO-related oceanic low pressure convergence

center forms; it then continually pulls dry air from Central Asia, desiccating India

during what should have been the humid summer monsoon season. This reversed

airflow causes India’s droughts. The extent that an ENSO event raises sea surfaces

in the central Pacific Ocean influences the degree of drought. However, it is not

well proved theory.

Extremes: The average annual precipitation of 11,871 mm (467 in) in the village

of Mawsynram, in the hilly northeastern state of Meghalaya, is the highest recorded

in Asia, and possibly on the Earth. The village, which sits at an elevation of

1,401 m (4,596 ft), benefits from its proximity to both the Himalayas and the Bay

of Bengal. However, since the town of Cherrapunji, 5 km (3 mi) to the east, is the

nearest town to host a meteorological office (none has ever existed in Mawsynram),

it is officially credited as being the world’s wettest place. In recent years, the

Cherrapunji-Mawsynram region has averaged 9,296 mm (366 in) of rain annually,

though Cherrapunji has had at least one period of daily rainfall that lasted almost

two years. India’s highest recorded one-day rainfall total occurred on 26 July

2005, when Mumbai received more than 650 mm (26 in); the massive flooding

that resulted killed over 900 people.

In terms of snowfall, regions of Jammur and Kashmir, such as Baramulla in

the east and the Pir Panjal Range in the southeast, experience exceptionally heavy

snowfall. Kashmir’s highest recorded monthly snowfall occurred in February of

1967, when 8.4 m (331 in) fell in Gulmarg, though the IMD has recorded snowdrifts

up to 12 m (39 ft) in several Kashmiri districts. In February of 2005, more than 200

people died when, in four days, a western disturbance brought up to 2 m (7 ft) of

snowfall to parts of the state.


Chapter 5

Climate Change

5.1 Introduction

One issue that received wide media coverage relates to recent spurt in natural

disasters felt globally such as Earthquakes/Tsunamis, cyclones/Typhoons/Hurricanes,

floods & droughts, heat & cold waves, etc. These were attributed to man-induced

changes to climate, more particularly to the so-called global warming.

The politicians, bureaucrats, environmentalists, NGOs are giving so much

importance to a phenomena that is not well understood by themselves but at the

same time they are not giving the same and equal importance to direct affects of

pollution on air, water, soil and food and their consequent effects on human,

animal and plant life, that is on life forms. It is just because the climate change

aspects of pollution, known as indirect effects, have billions of dollars to share but

the same is not the case in the area of direct consequences of pollution by which

common man suffers, more particularly in developing countries.

Extreme natural events become disasters when they affect settlements,

economic and social activities. Whether a given phenomenon is equated to a

disaster does not depend so much on its intensity as on its impact on society. The

public measure the intensity of the system based on deaths and destruction of

property. The damage is far less before 1960s when compared to damages after

60s in terms of numerical numbers but when we consider the percent figures of

that time they are not different. Therefore, in all these cases the place of occurrence

plays an important role in terms of damage.

Scientific point of view the intensity/severity of natural disaster is different

from the public point of view. The public experience present a short span of years

while scientists experience relates to a long period of historical scale of years.

Media is more interested in the view point of public rather than scientists view

point, because the former group represent numerically far more in number than

the later group and at the same time gives big hype.

This is exactly what is happening with Intergovernmental Panel on Climate

Change (IPCC) perspective of climate change. With this every thing has become

unusual and try to attribute to some thing they don’t have the comprehensive

knowledge like a blind man using a light pole. In floods and droughts in recent

years political floods and droughts play important role over the scientific floods

and droughts – that is motivated floods and droughts gets more publicity. Most

unfortunately, man on the street to Editor of scientific magazines talk of climate

change at the same wavelength, and thus science became a scapegoat!!!

The same can be said with modern climate change research. The group

that is using the modern model based global warming and their impact get big

hype compared to people engaged in understanding the nature in its’ true


perspective like natural rhythm that help agriculture in true sense. In the modern

world of Western based science, awards/rewards go to modelers, promotions go to

modelers!!! People talks of science are considered as outcastes. Therefore, it is the

responsibility of scientific groups to clear this ambiguity, so that it is easy to

understand the impact of such events on environment and thereby on human,

animal and plant life under different time and space scales. The same is evident in

modern politics. When a famous person from a particular field with mass connection,

when he says some thing people blindly believe him with out knowing his real

background. So, it is easy to cheat gullible public. A known enemy is better than

an unknown enemy. Here media plays the spoilsport. Let us see how, the media

without understanding the basics create controversies!!!

A recent report says, “In the debate on global warming, the data on the

climate of Antarctica has been distorted, at different times, by both sides. As a

polar researcher caught in the middle, I would like to set the record straight. In

January 2002, a research paper about Antarctic temperatures, of which I was the

lead author, appeared in the journal Nature. At the time, the Antarctic Peninsula

was warming, and many people assumed that meant the climate on the entire

continent was heating up, as the Arctic was. But the Antarctic Peninsula represents

only about 15 percent of the continents landmass, so it could not tell the whole

story of Antarctic climate. Our paper made the continental picture clearer. My

research colleagues and I found that from 1986 to 2000, one small, ice-free area

of the Antarctic mainland had actually cooled. Our report also analyzed temperatures

for the mainland in such a way as to remove the influence of the peninsula warming

and found that, from 1986 to 2000, more of the continent had cooled than had

warmed. Our summary statement pointed out how the cooling trend posed

challenges to models of Antarctic climate and ecosystem change. Newspaper and

television reports focused on this part of the paper. And many news and opinion

writers linked our study with another bit of polar research published that month,

in Science, showing that part of Antarctica’s ice sheet had been thickening and

erroneously concluded that the Earth was not warming at all. Scientific findings

run counter to theory of global warming, said a headline on an editorial in The San

Diego Union-Tribune. One conservative commentator wrote, It is ironic that two

studies suggesting that a new Ice Age may be under way may end the global

warming debate. In a rebuttal in The Providence Journal, in Rhode Island, the lead

author of the Science paper and I explained that our studies offered no evidence

that the earth was cooling. But the misinterpretation had already become legend,

and in the four and half years since, it has only grown. Our results have been

misused as evidence against global warming by Michael Crichton in his novel

State of Fear and by Ann Coulter in her latest book, Godless: The Church of

Liberalism. Search my name on the Web, and you will find pages of links to

everything from climate discussion groups to Senate policy committee documents

all citing my 2002 study as reason to doubt that the Earth is warming. One recent

Web column even put words in my mouth. I have never said that the unexpected

colder climate in Antarctica may possibly be signaling a lessening of the current

global warming cycle. I have never thought such a thing either.


Our study did find that 58 percent of Antarctica cooled from 1986 to 2000. But

during that period, the rest of the continent was warming. And climate models

created since our paper was published have suggested a link between the lack of

significant warming in Antarctica and the ozone hole over that continent. These

models, conspicuously missing from the warming-skeptic literature, suggest that

as the ozone hole heals thanks to worldwide bans on ozone-destroying chemicals

all of Antarctica is likely to warm with the rest of the planet. Also missing from

the skeptics’ arguments is the debate over our conclusions. Another group of

researchers who took a different approach found no clear cooling trend in Antarctica.

We still stand by our results for the period we analyzed, but unbiased reporting

would acknowledge differences of scientific opinion. The disappointing thing is

that we are even debating the direction of climate change on this globally important

continent. And it may not end until we have more weather stations on Antarctica

and longer-term data that demonstrate a clear trend. In the meantime, I would like

to remove my name from the list of scientists who dispute global warming. I know

my coauthors would as well”.

5.2 What is Climate Change?

“Climate Change” is a change in the “average weather”. Climate refers to

the weather over very long periods, while the weather is what we experience daily.

In the past climate change refers to the “Systematic Natural Rhythm”, expressed

in the form of cycles with different time scales. In recent years, it invariably refers

to one component of man-induced changes, expressed in the form of global warming

“trend”. The major culprit in this sordid episode is the Intergovernmental Panel on

Climate Change [IPCC). As long as it was in the hands of scientific organization,

namely World Meteorological Organization [WMO] it was in the hands of scientific

groups. Once it was put in the hands of a political organization such as IPCC it

went into the hands of non-scientific-vested groups. In this, public relation campaign

by vested groups played major role over the science. It is the greatest tragedy in

the annals of history of science. It is clear from the way IPCC gave weight to

majority individual/organizations opinion without valid scientific base and tried to

manipulate science to prove its’ point. In the same line, Indian scientists are

enthusiastic in “thinking locally and acting globally” instead “thinking globally

and acting locally”. Basically because of this attitude the scientists invariably give

weight to Westerners unproved-semi-empirical models. These are far from ground

realities. By this way the responsible scientific community leading the planners in

wrong way. The Public Relation Campaign in this direction by vested groups

“fetched” Noble Prize to IPCC & Al Gore former Vice-President of USA. This has

given a big hype to the unproven arguments. Even when authors of the theory are

skeptical about the issue, yet the public relation campaign groups became more

aggressive in their campaign, causing irrevocable damage to science of climate

change. It turned into another political vote catching type campaign in developing

countries.

Man within his understanding of the subject/nature formulates models with

several unknown factors missing; while ground truth is the result of integrated


effect of known and unknown factors. This exactly what is happening in the

global warming and its’ so called impact. While making sweeping conclusions

based on such imperfect mathematical models one must be cautious and careful.

At the same time while presenting results, one must not present/discuss in isolation

but present/discuss in an integrated manner. That is exactly what is needed for

planning. In fact weather plays major role in Indian economic context, as it is an

agriculture nation in which agriculture is driven by weather.

For example, Reddy (1995a) presented 3 points of difference of series of

articles by top scientific groups of the world on the importance of radiation term

in crop growth, where one author says yes/correct and the other author says no/

not correct, from the series of discussion papers published in 1994 in Agric. For.

Meteorol., 68:213-242. After integrating these studies in holistic manner, Reddy

come up with more pragmatic and practical approach to be useful in real conditions,

by explaining the limitations of individual approaches by taking components in

isolation. Reddy (1995b) reviewed the result of McKenny & Rosenberg (1993)

results estimated using GISS & GFDL general circulation models for doubled


atmospheric CO2 , on the expected climate change induced effects on

meteorological parameters (Figure 5a) that are inputs into crop models – Down To

Earth presented sensitivity of land suitable for cereal production to climate change

(Figure 5b). Reddy observed changes observed in parameters are far less than

those expected from the model-induced error ranges. That is, first the model’s

applicability in holistic condition must be proven beyond doubt, which the authors

have not attempted.

Like in the climate change & genetically modified crops of MNCs, there are

large vested interest groups that present public relation campaign in artificial rain

making (cloud seeding) by simply highlighting the isolated results. Reddy (2004)


presented a review of the literature on cloud seeding in a holistic context and

observed “The experiments so far conducted suggested that, with few exceptions,

conclusive cloud seeding is not producing the desired results. The Indian experience

is not much different from this conclusion. It is important to note that a successful

experiment in one region does not guarantee that seeding in another region will

be successful unless environmental conditions are replicated as well as the

methodology of seeding. Such a situation is hypothetical”. To counter this, the

seeding agencies invariably seed a severe-active synoptic system and present the

results as the outcome of cloud seeding operations and without showing how

much rainfall was reduced by seeding a strong-active system that give copious

rainfall in the down wind direction in normal circumstances. Here also isolated

things are attributed to holistic situation by falsifying the facts before ignorant

politicians.

It has become a common reporting saying “global warming is the increase in

the average temperature of the Earth’s near-surface air and Oceans in recent decades

and its projected continuation. The IPCC concludes most of the observed increase

in globally average temperature since the mid-twentieth Century is very likely due

to the observed increase in anthropogenic greenhouse gases concentrations via

the greenhouse effect. Natural phenomena such as solar variation combined with

volcanoes probably had a smaller warming effect and pre-industrial times to 1950

and a small cooling effect from 1950 onward. These basic conclusions have been

endorsed by at least thirty Scientific Societies and Academies of Science. While

the individual scientists have voiced disagreement with some findings of the IPCC,

the overwhelming majority of scientists working on climate change agree with

IPCC main conclusion”. The basic question to be answered from such

pronouncements is: scientific studies should be based on what many accepted or

endorsed; or based on what is scientifically correct? But unfortunately, the public

Relation activists put emphasis in the number game!!! In this connection, let me

give three examples from my experience (Reddy, 1983; Reddy, 1983-84; Reddy,

1993; Reddy, 1995a; Reddy, 2002b):

Firstly, while I was a Ph.D. student in Australia, it became a big issue why I

am not using a particular model, which is being in wide use in Australia including

a student from my department completed his Ph.D. thesis using that model. They

asked my explanation on this. I presented to them stating that this is a static

model. Discarding his thesis, then the Ph.D. student took up another topic and

completed his Ph.D. We both received our Ph.D.s in 1985. This is science!!!

Secondly, FAO Headquarters asked my explanation in writing, why I am

using a different model in my work instead of FAO-Agro-ecological zones concept

as an FAO Expert. I gave my scientific report stating that this is a static model.

After hearing my explanation, they asked me to modify the model. I did not do it

as it has some inherent weaknesses. In fact when I presented a talk on the

agroclimatic classification developed by me in 1981, the scientist who was involved

in the development of the FAO model was also present at my talk. He left the

organization; he adopted over simplified version of mine and used monthly data


instead weekly data, which was used in my concept. With this the model became

static. This is science!!!

Thirdly, to present the solar radiation impact on crop, three different groups

started publishing articles with contradicting observations. This was clarified by

presenting the results in an integrated manner saying that all are correct (Reddy,

1995). This is science but not “numerical number” as adopted by IPCC to bulldoze

the science!!!

Dr. James E. Hansen, Director of Space Studies at the National Aeronautics

and Space Administration was a principal author of one of the first papers spelling

out the links between rising atmospheric levels of Carbon Dioxide (CO2) and rising

global temperatures as back as 1981. In 2000, he along with his colleagues reported

in the proceedings of the National Academy of Sciences, USA that the global

warming seen in recent decades was not caused by CO2 but mainly by other heat

trapping emissions Methane [CH4], CFCs, black particles of diesel & coal soot,

and other compounds that create the ozone in smog. Thus, Dr. James E. Hansen

introduced politics of CO2 & CH4 as a function of developed vs developing

countries like India. And yet, it would be appropriate here to mention that the

eminent NASA scientist James Hansen, the man who could be called the father of

global warming theory, admits that it was impossible to come up with reliable

climate models because there is too much about the climate that scientists don’t

understand. Thus, the entire global warming theory rests on the validity of trapping

theory and so far no valid “one to one theory” was presented!!! .

5.3 Data Types

Historical documents contain a wealth of information about past climates.

Observations of weather and climatic conditions can be found in ship and farmers’

logs, travelers’ diaries, newspaper accounts, and other written records. When

properly evaluated, historical data can yield both qualitative and quantitative

information about past climate. There are, also, several other ways that Scientists

study how the Earth’s climate is changing: satellites, instrumental records, historical

records and proxy data. Some scientists look to satellites to study the Earth’s

changing climate. However, the satellite record is too short (around. 20 years) to

provide much perspective on changing climate and yet they throw some light to

interpret in right direction the ground based observations.

Instrumental weather records: The record of instrumental weather measurements,

extending back into the 19th century, provides data from thermometers, rain gauges,

historical documents and other instruments. However, this record is too short to

study many climatic processes. Also, because we have few instrumented observations

from before the major industrial releases of carbon dioxide began, it is difficult to

separate human and natural influences on climate. However, these records throw

light on the short term natural rhythm in built in the nature, like cycles in precipitation

that play an important role in agriculture and water resources availability. One

must be careful while interpreting meteorological data as the change of units of

measurements like inches to millimeters in rainfall; degrees Fahrenheit to degrees


Celsius in temperature may lead to abrupt changes as the former are bigger units

while later are smaller units. One inch is 2.5 cm or 25 mm.

Palioclimatological weather records: Paleoclimatologists gather proxy data from

natural recorders of climate variability such as tree rings, ice cores, fossil pollen,

ocean sediments, corals and historical data. By analyzing records taken from these

and other proxy sources, scientists can extend our understanding of climate far

beyond the 100+ year instrumental record. Thus, Paleoclimatology is the study of

climate prior to the widespread availability of records of temperature, precipitation

and other instrumental meteorological data that can help to establish the range of

natural climatic variability in a period prior to global scale human influence. If

there is one thing that the paleoclimatic record shows, it is that the Earth’s climate

is always changing. Climatic variability, including changes in the frequency of

extreme events (like droughts, floods and storms), has always had a large impact

on humans. For this reason, scientists study past climatic variability on various

time scales to gain clues that will help society plan for future climate change.

The study of paleoclimates have been particularly helpful in showing that

the Earth’s climate system can shift between dramatically different climate states

in a matter of years and/or decades. Understanding “climate surprises” of the past

is critical if we are to avoid being surprised by abrupt climatic change. The study of

past climate change also helps us understand how humans influence the Earth’s

climate system. The paleoclimatic record also allows us to examine the causes of

past climate change, and to help unravel how much of the present observed changes

may be explained by natural causes, such as solar variability, and how much may

be explained by human influences.

Lastly, most state of the art climate prediction is accomplished using large

sophisticated computer models of the climate system. A great deal of research

has been focused on ensuring that these models can simulate most aspects of the

modern, present-day, climate. It is also important to know how these same models

simulate climate change. This can be accomplished by comparing simulations of

past climate change with observations from paleoclimatic records. Thus,

paleoclimatology helps us improve the ability of computer models to simulate

future climate. Some of these are given as follows:

Corals — Corals build their hard skeletons from calcium carbonate, a mineral extracted

from seawater. The carbonate contains isotopes of oxygen, as well as trace metals,

that can be used to determine the temperature of the water in which the coral

grew. These temperature recordings can then be used to reconstruct climate when

the coral lived.

Fossil Pollen — All flowering plants produce pollen grains. Their distinctive shapes

can be used to identify the type of plant from which they came. Since pollen

grains are well preserved in the sediment layers in the bottom of a pond, lake or

ocean, an analysis of the pollen grains in each layer tell us what kinds of plants

were growing at the time the sediment was deposited. Inferences can then be

made about the climate based on the types of plants found in each layer.


Tree Rings — Since tree growth is influenced by climatic conditions, patterns in

tree-ring widths, density, and isotopic composition reflect variations in climate.? In

temperate regions where there is a distinct growing season, trees generally produce

one ring a year, and thus record the climatic conditions of each year. Trees can

grow to be hundreds to thousands of years old and can contain annually resolved

records of climate for centuries to millennia.

Ice Cores — Located high in mountains and in polar ice caps, ice has accumulated

from snowfall over many millennia. Scientists drill through the deep ice to collect

ice cores. These cores contain dust, air bubbles, or isotopes of oxygen that can be

used to interpret the past climate of that area.

Ocean & Lake Sediments — Billions of tons of sediment accumulate in the

Ocean and the Lake basins each year. To interpret part climates, scientist drill cores

of sediment from the basin floors of the Ocean and the Lake that include tiny

fossils and chemicals.

5.4 Climate Change

Good weather records extend back less than 150 years in most

places. In that time, the Earth’s global average temperature has increased

by approximately 0.5 0C or 0.9 0F. Scientists are trying to determine how much of

this warming is a natural fluctuation and how much is a result of human induced

greenhouse warming. However, this tends to be confined to one parameter of

weather, namely temperature as it plays vital role in the developed nations as they

being located in extra-tropical zone.

Since the end of the last ice age occurred over 10,000 years ago, the planet

has continued to undergo changes in climate. Warming during medieval times and

cooling during the “Little Ice Age” a few centuries ago dominate the last millennia.

From paleoclimate records, we know that the climate of the past million years has

been dominated by the glacial cycle, a pattern of ice ages and glacial retreats

lasting thousands of years.

The changes in ice cover over the Northern Hemisphere. Eighteen-thousand

years ago, at the peak of the last ice age, scientists estimate that nearly 32% of

the Earth’s land area was covered with ice, including much of Canada, Scandinavia,

and the British Isles. These glaciers developed because the Earth was in the midst

of an ice age. Today ice coverage about 10% of the Earth’s land surface.

However, the literature review present that the “climate change” has two

components, namely systematic variations that are in built in nature and the trend

that is created by man’s action on nature. The systematic variations, known as

cyclic variations, are ground-realities that are the outcome of interaction with

known & unknown factors that are beyond the control of man. The trend is

caused by several factors that are associated with man’s action on nature; and

modern scientists are contemplating this to solely to global warming or rise in

temperature. The recent unusual events are also attributed to global warming

phenomena. As Indian economy is weather driven, it is essential that while making


any inferences on weather & climate, this must be looked into in an integrated

manner rather than in isolation.

Up to around 1980s the studies on “climate change” were principally related

to natural variations in climate and the impact of ecological changes on climate at

local & regional level. The natural variations in the climate were studied using

historical climate data, sediments, tree rings, etc along with solar phenomena like

sunspot, solar flares, etc. Ecological changes primarily related to land-use changes

and land cover such as de-forestation, changes in orography/topography, changes

in human habitations & urbanization, agriculture, etc [Reddy & Jayanthi, 1974;

Reddy & Rao, 1977; Reddy, 1984; Reddy, 1993; Reddy, 2000a; Reddy, 2007].

These were integrated with the dry-land agricultural planning in developing countries

[Reddy, 1983-84, 1993, 2002a].

Now these are more or less masqued by the global warming concept primarily

estimated using unsound mathematical models. Yet scientists started flooding the

magazines with mind-boggling predictions on what happens to agriculture, health,

sea level, etc [Raj Chengappa, 2002; Paul R. Epstein, 2000; McKenney & Rosenberg,

1993].

To provide a clear picture on climate change, the study of climate change is

divided into two parts, namely natural variations that are in built in the nature that

are beyond man’s control and the other, changes induced by man’s actions

represented by trend, which are the creation by man. The natural variation part of

climate change has irregular and systematic variations. Day-to-day, month-to-

month, year-to-year variations form part of irregular variations. The systematic

variations part is dealt in Chapter 6. The man-induced variations also have two

distinctive parts, namely ecological changes dealt in Chapter 7 and global warming,

dealt in Chapter 8. The issues of unusual events vs global warming are dealt in

Chapter 9.


Chapter 6

Systematic Variations

6.1 Ancient Lore

The science of astrology started with the understanding of seasons and

weather in relation to movement of extraterrestrial bodies known as planets; this

understanding of ancient lore later became the science of astronomy, as a guide

to fight wars, develop medicine to cure diseases, and practice agriculture, all of

which were more seasonal. All, or most, cultures have developed a form of astrology

such as Indian Astrology, Western Astrology, Chinese Astrology, Mexican Astrology,

Celtic Astrology, etc. (Reddy, 2000b). The Western System is solar-based, the

Chinese system is lunar-based, and the Indian system is luni-solar based. By the

use of certain fixed stars, calendars were evolved to mark the movements of the

Sun, the Moon, and the planets with reference to a point on the Earth.

There was a category of priests trained to understand the lore of the

divinatory calendars, which was one of the foundations of higher learning. One of

the most fascinating and enchanting features about the practice of astrology is

the fact that Indian astrologers, and the technique they use, often differ dramatically

from town to town in India. However, there are no differences in the basic concept.

They are the highly respected group in the society. It is a family tradition of

astrological education. A lot of this ancient lore lost its glory with industrialization,

as the family tradition in astrology lost its shine. In addition, the basic point

around which astrological calculations are made also became erroneous. The principal

activity was the time reckoning and the calendar computations in terms of the

motion of the Sun, the Moon, and the planets along the zodiacal path with which

were also associated 27 nakshtras. According to the ruling planet of a year, overall

rainfall of that particular year should be anticipated as follows: Sun – moderate;

Moon – very heavy; Mars – scanty; Mercury – good; Jupiter – very good; Venus –

good; and Saturn – very low, etc. On every New Year day the respected gentlemen

present what is in store in terms of weather, agriculture, expected political turmoils,

disasters, etc. This ancient science of predicting rainfall talks about the wind

direction. In northwest India the wind direction on Holi, the full-moon day of the

last Hindu month Phalguna (approximately March) and wind direction on

Akshayatrutiya, the third day of the month Vaisakha (approximately May) were

used to predict whether the monsoon would be early or late (Reddy, 2005). Reddy

(1977) observed a clear relationship between the onset of the monsoon over the

Kerala Coast and the zonal component of wind at 50 mb level over Singapore

(which presents a systematic variation with time), an equatorial station in the

month of May. If the winds are westerly then the monsoon is early; if the winds

are easterlies, the monsoon is late.

The Chinese system of astrology has a 60-year cycle. This is based on a

combination of five elements and twelve animal signs. In Indian astrology, the


calendar system is the same as or similar to what is called the 60-year cycle

[Prabhava (1987-88), Vibhava, — Krodhana, Akshaya (2046-47)] – the cycle of the

Sun (6 years) and the Moon (10-years), i.e., 6 of 10 years; or the cycle of Jupiter –

a cycle of five 12 years, similar to the Chinese 60-year cycle. The Indus Valley

Civilization, which was before the Vedic period used the 60-year cycle. The Indian

cycle is later by 3 years than the Chinese cycle. In both Indian and Chinese

astrology, the 60-year cycle is more in relation to the Moon/nakshatras. Similar to

this, the All-India Southwest Monsoon rainfall also presents a 60-year cycle. This

rainfall cycle lags by 3 years to Indian astrological cycle. The present 60-year cycle

in Chinese astrological cycle started in 1984-85 will continue upto 2043-44; in

Indian astrological cycle started in 1987-88 will continue upto 2046-47 and in the

All-India Southwest Monsoon rainfall started in 1990-91 will continue upto 2049-

50.

The Aztecs noted that 5 Venus years equal to 8 Sun years. These cycles

only repeated after 65 Sun and 104 Venus years, i.e., once in 520 years. The

number 104 is the longest period in Mexican time keeping, and was called one “old

age”. The Mexican “Century” was 52 years. Similar to this, the rainfall data of

Fortaleza in Brazil in Southern Hemisphere presents a 52-year cycle as well the

onset of monsoon over Kerala Coast in India in the Northern Hemisphere around

the same latitude belt.

6.2 Sun-Weather Relationship

King (1975) presented an important review of the scientific articles on the

Sun-Weather relationship appeared in the literature up to that time. He states “As

they profoundly influence civilization, and have not been well explored, Sun-Weather

relationships should become a major field of research in the decades being ushered

in by GARP and IMS”. He also further states, “Many people have suggested in the

past that the weather is influenced by the 11- and 22-year (double sunspot cycle)

sunspot cycles” — Figure 6a presents 400 years of sunspot observations (bottom)

and solar cycle variations during 1975 to 2005 (top). He further says that “I believe

that the accumulated evidence is so compelling that is no longer possible to deny

the existence of strong connections between the weather and radiation changes

(electromagnetic and/or corpuscular) associated with a whole range of solar

phenomena. Even the most skeptical scientist who investigates the literature

thoroughly will be forced to concede that important aspects of lower-atmospheric

behavior are associated with solar phenomena ranging from short-lived events

such as solar flares, through 27-day solar rotations to the 11-year, 22-year, and

even longer solar cycles”.

Sunspot Cycles: King (1975) presents that Xanthakis in 1973 observed (Figure

6b) at higher latitudes in Northern Hemisphere (70-80 degrees) the 11-year solar

cycle was positively correlated with 10-cm oscillation in the annual rainfall analysis

total; between 60-70 degrees they are negatively correlated and at lower latitudes

(50-60 degrees) a negative correlation existed before about 1915 and a positive

correlation after that. The three zones respectively based on 12, 22 & 36 stations


data. Brown in 1974 observed opposite pattern at 17 degrees and 43 degrees in

Southern Hemisphere in the rainfall oscillations associated with the 11-year sunspot

cycle (Figure 6c). The curves were obtained by applying an 8-15 year filter to the

annual differences. King in 1973 also observed opposite ways at 55 and 35 degrees

in the Northern Hemisphere. Scientists noticed that the 11-year sunspot cycle is

not fixed but vary between 9 to 13 years.

The solar-cycle-induced rainfall oscillations referred to range from about 3

to some 50% of the normal annual total. Obviously, a reduction of rainfall by

25% in each of several years around one of the extremes of the sunspot cycle is of

considerable importance. Analyses combining data from zones exhibiting opposite

solar cycle effects will invariably lead to the erroneous conclusion that no solar

cycle effect exists, as well as an analysis of rainfall data from regions situated

between zones in which the sunspot cycle effect is opposite. Such variations with

latitude are quite obvious as the climate systems differ.

The annual rainfall totals at Fortaleza, Brazil by Markham in 1974 (Figure 6

d) and at three sites in South Africa by Tyson in 1974 (Figure 6e) were positively

correlated with the “double” sunspot cycle for considerable periods of time. Both

these are from Southern Hemisphere. The modulation associated with the double


cycle amounted to about 35% of the average annual total at Fortaleza and at

about 25% of the average rainfall at the South African stations. The data from

Fortaleza are available from 1865 onwards. After the first 60 years the relationship

between the rainfall and the double cycle at Fortaleza changed phase. The 50

years of data available from South Africa show a consistent positive correlation

with the double cycle. According to Tyson & his co-authors in 1974 the African

rainfall data for latitudes south of those where the double sunspot cycle influence

is observed exhibit a pronounced oscillation having a period of about 10 years in

anti-phase with the sunspot cycle as noted by King & his co-authors in 1974.

Cornish in 1936 & 1954 and Whippe in 1936 in Adelaide, Australia observed

impressive evidence of an association between rainfall and double sunspot cycle

(Figure 6f). Cornish in 1954 concluded that this oscillation must be due to

secular changes in the latitudinal paths of anticyclones with their attendant cyclones

across southern Australia. Bodurtha in 1952 reported that the sunspot cycle


strongly influences both the frequency and the intensity of anticyclogenesis, so it

may be concluded that the number and intensity of anticyclones and the latitudes

at which they occur all vary during the solar cycle.

King & his co-authors presented another striking illustration of the influence

of the double sunspot cycle on the weather in 1974 (Figure 6g). The July

temperature in central England during the period 1750-1880 exhibited an oscillation

of nearly 1 oC in phase with double sunspot cycle. The temperature curve is

somewhat anomalous during the years 1840-1855 when the temperature extremes

occurred around sunspot minima instead of near sunspot maximum. Brooks in

1951 presents that it appears to be firmly established is that over the world as a

whole, and especially in the tropical regions, the mean air temperature at the

Earth’s surface varies in opposition to the sunspot cycle, being the lowest at

sunspot minima.

The double sunspot cycle appears to influence the climate of the United

States in several ways. Thomson in 1973 and Roberts in 1974 have shown that

droughts in various parts of the country occur around every second sunspot minima.

Newman in 1965 has shown that winter temperatures in Boston exhibit a 22-year

periodicity. Thompson in 1973 reported a remarkable correlation between the

July/August temperature in the corn belt of United States and the double sunspot

cycle. Mather in 1974 presented striking evidence between double sunspot cycle

and temperature in the US. Willett in 1961 discussed the possible relationship

between the weather and the 80-year sunspot cycle.

A sunspot cycle induced meteorological variation may suddenly reverse phase

(Figure 6b). King presented two such examples. Brooks in 1951 observed in his

reviews of the relationships between solar and meteorological phenomena that

over the world as a whole and especially in the tropical regions, the mean air

temperature at the Earth’s surface varies in opposition to the sunspot cycle, being

lowest at sunspot maxima and highest at sunspot minima. This was suspected by

Hershel as early as 1801 but was first clearly demonstrated by Koppen in 1873 and

has since been confirmed by Mieke in 1913, Hildebrandson in 1914, Walker in

1915 & 1923, Mecking in 1918, Clayton in 1923, Droste in 1924 and others. In

their Handbook of Statistical Methods in Meteorology, Brooks & Carruthers in

1953 examined the significance of some of the negative correlations between

tropical temperatures and sunspot numbers and concluded that they were

undoubtedly significant. Although the tropical temperatures examined by the

early workers referred to by Brooks correlated negatively with sunspot number,

Troup in 1962 pointed out a relatively recent reversal of this “Over the tropics as a

whole, the correlations between sunspot number and tropical temperatures which

were negative prior to 1920 have become zero or even positive subsequently. Of

recent years there has apparently been a reversal in the phase of the temperature

cycle”.

The level of the water in Lake Victoria, positively correlated with sunspot

number before about 1930, has been negatively correlated since about 1950;


during the interim period little correlation existed between sunspot number and

the water level. Stringfellow in 1974 observed a good relationship between Five-

year means of the Annual Lightning events index in Great Britain and sunspot cycle

(Figure 6h). Brooks in 1934 first showed that a significant relationship exists

between the occurrence of thunderstorms and the annual sunspot numbers:

correlation coefficients up to 0.91 were obtained from long series of data, the

largest correlation coefficients relating to high latitudes. In 1953 Brooks and

Carruthers made this observation: ”There is a correlation coefficient of +0.88

between the number of thunderstorms recorded in Siberia and mean annual sunspot

relative number. Since it is inconceivable that thunderstorms in Siberia cause

sunspots, it is reasonable to assume that sunspots or some other solar phenomenon

associated with sunspots cause thunderstorms”. They also established statistically

that the observed variation of the frequency of thunderstorms in the West Indies

during the sunspot cycle was definitely significant, the probability of obtaining

the correlation by chance being less than 0.1% “We have established”, they said,

“a high probability that thunderstorm frequency in the West Indies is related in

some way to the sunspot maximum”.

Schostakowitsch made one of the most comprehensive investigations of

the influence of the solar cycle on the weather. He prepared detailed global maps

(reproduced by Clayton in 1933) showing how the temperature, pressure and rainfall

over the Earth vary between sunspot minimum and maximum. Reddy & Lahori

(1977) subjected to power spectrum & harmonic analysis the monthly mean data


of dynamic height of constant pressure surface, temperature and eastward &

northward velocities of wind at 100, 50 & 30 mb levels from eleven equatorial

stations in the latitude belt of 13.5 degrees north latitude to 12.0 degrees south

latitudes. It was noted the quasi-biennial Oscillation (QBO) the 5th harmonic of

sunspot 11-year cycle is acting in unison with the multiple mode of annual cycle,

where higher modes are prominent at low sunspot activity and lower modes at

higher sunspot activity. That is near the maximum sunspot activity the QBO is 10-

24 months and near the minimum sunspot activity the period of QBO is 30-36

months. This type of variation may be attributed to the modulating effect of

annual cycle, where the amplitude of annual cycle is maximal. Reddy et al. (1977)

subjected the monthly mean data for 44 to 67 years at 20 stations of total solar

radiation and net radiation intensities estimated using simple models (see Chapter

3) to power spectrum analysis. The results presented significant influence of sunspot

cycle on total solar radiation and net radiation intensities.

Solar flares: Several analyses have indicated that short-lived solar phenomena,

such as solar flares, magnetic field, etc, may trigger a response in the lower

atmosphere. Schuurmans in 1965 studied the tropospheric response to solar flares

using the change in height of the 500-mb level over much of the Northern

Hemisphere during the first 24 hour after each of 53 flares. He concluded that the

pattern of height changes “shows a remarkable regularity with a symmetry with

respect to the geomagnetic rather than to the geographic pole”. Results such as

these show that the circulation of the lower atmosphere is significantly modified

after solar flares.

Reddy & Rao (1977) studied the effect of solar flares on lower tropospheric

(i.e. ground surface, 850, 700 and 500 mb levels) temperature and pressure (i.e.

dynamic height of constant pressure surface) using 81 flares for the period 1957-

59 at few selected locations in India. The analysis showed that the effect of solar

flare occurs within 24-hr period, while the influence starts receding after 48-hr.

The change in magnitude of the flare influence is observed to decrease with

decreasing of altitude. The effect on pressure is more pronounced compared to

that on temperature. As the change in the magnitude of the solar flare influence is

seen to depend on the intensity of the flare but not on the time of occurrence of

the flare. The same type of seasonal variation (i.e. winter maximum and summer

minimum) was not seen at all the stations, but this variation shows a considerable

relation to the general circulation pattern prevailing at that time over the region –

low & high pressure belts. That is, the authors noted significant influence of solar

flares on lower tropospheric weather in association with prevailing synoptic weather

conditions.

Solar phenomena tend to recur with periods of the order of 27 days, the

synodic period of revolution of the Sun. Panofsky in 1967 has shown that this

period is close to the period of the maximum fluctuations of mean west winds at

upper-middle latitudes. Similar behaviour is not observed at lower latitudes. After

an investigation of the 500-mb circulation along the auroral belt, Riehl in 1956

concluded that circulation increases and decreases take place with a period which


can be related to the mean solar rotation in the equatorial zone. Rosenberg and

Coleman in 1974 studied the southern California rainfall power spectrum and

concluded that there is a significant peak at almost exactly 27 days. Baerkes in

1955 has reported the existence of a 27-day periodicity in wind speed and Egyed

in 1961 noted a 27-day periodicity in soil temperature. Rao & Reddy (1972 a & b)

and Reddy (1974a) studies on surface winds & rainfall at few Indian stations

present significant solar and lunar influence. We are well aware the sea/ocean

tides vary with phases of the Moon.

Magnetic field: Many authors including Sazonov in 1965, Mustel in 1966, Baynon

and Winstanley in 1969, Roberts and Olson in 1973, Stolov and Shapiro in 1974,

and Sidorenkov in 1974 have reported that Earth’s magnetic field may play a role

in bringing some sun-weather relationships (Figures 6i presented by Wollin and

co-authors in 1973 & Wales-Smith in 1973). Figure 6j presented by Wollin and

co-authors in 1974, for example, shows oxygen-isotope data, which provide a

measure of temperature and magnetic intensity values obtained from a single

deep-sea core formed during a 500,000-year period. Cold epochs occurred when

the magnetic intensity was relatively high and vice versa. King and Willis in 1974

have suggested that the “Little Ice Age” which occurred in Europe between 1550

and 1850 (Figure 6k) was associated with the unusually high values of magnetic

inclination that existed at that time.

Milankovitch Cycles in Paleoclimate: Milankovich cycles are cycles in the Earth’s

orbit that influence the amount of solar radiation striking different parts of the

Earth at different times of year. They are named after a Serbian mathematician,

Milutin Milankovitch, who explained how these orbital cycles cause the advance


and retreat of the polar ice caps. Although they are named after Milankovitch, he

was not the first to link orbital cycles to climate. Adhemar in 1842 and Croll

in1875 were two of the earliest.

Ozone: The total ozone content of the atmosphere also varies during the sunspot

cycle and possibly during the short-lived solar events. Various authors, including

Willet and Prohaska in 1965, Christie in 1973 and Paetzold in 1973 have described

variations of ozone content that occurred during the sunspot cycle while Dobson

and his co-authors in 1929 said “there is a small but definite tendency for days

with much ozone to be associated with magnetically disturbed conditions”. Weeks

and co-authors in 1972 concluded that the ozone content is reduced during strong

solar proton events.

Prior to 1980 the Sun-Weather relationship was an important topic for

research and achieved significant results by scientists from the globe. Once after

the papers linking global temperature increases to greenhouse gases, the entire

focus of research changed and as a result the research priorities completely changed

and sun-weather-climate change aspects have gone in to oblivion. There is an

urgent need to re-look into these aspects and separate and thus the integrated

effect of the Sun on the short & long-term variations in weather-climate system.

6.3 Systematic Variations in Observed Data

In this section the Sun-Weather component was not linked but presented

studies on the possible patterns in observed historical precipitation data over different

parts of the globe, known as systematic variations / climatic cycles / climatic

fluctuations. Climatic fluctuations have profound effects on water resources. In


arid and semi-arid zones, climatic fluctuations affect many hydrological

characteristics of watersheds including quantity of base flow, the occurrence of

large floods. The importance of climatic fluctuations in agriculture was dealt by

Reddy (1993) with reference to several countries around the globe. The literature

is rich with studies on climatic fluctuations. The author presented in brief the

results of the climatic fluctuations from his studies.

Climates in the savanna of northern Africa have changed substantially over

the past few millennia (Jackson, 1957). Climatic changes over the shorter periods

have been identified in other parts of the world (Lamb, 1972). Trends of both

increasing and decreasing rainfall have been found in some places in the tropics.

Fluctuations that are repeated in time have been detected for some places in the

tropics (Dyer, 1977; Parthasarathy & Mooley, 1978). Dyer (1977) predicted that

the next period of drought in South Africa should occur in the middle of 1980. In

such situations the average climate discussed in Chapter 4 give misleading signal

to planners. The climate presented in Chapter 4 when discussed by taking into

account the trends & fluctuations provide the realistic conditions for better planning.

Lockwood (2001) presented a review of papers on climatic changes and

oscillations. Webb, et al. (2005) presented time series plot of the annual flow

volume for the Colorado River at Lee’s Ferry along with linear trend line. However,

without looking at abrupt change, fitting the data to linear curve give a misleading

conclusions and thus loose faith on such trend. For example, the fluctuations

from 1890 – 1930 showed a sudden drop and from around 1930 to 2000 presented

different fluctuations. There is a need to correct this sudden drop and that make

the results meaningful. This is an important issue while studying the observed

data series that may give spurious results. Also, it is important to take into account

the changes in units of measurements or place of observation, etc. In recent years,

in majority of developing countries the meteorological observatories are in dilapidated

condition.

Models: World Meteorological Organization (WMO) issued a Technical Note (No.

79) as back as 1966 on the subject “climate change”. One of the components of

this report is the assessment of climatic fluctuations in the observed meteorological

data series, known as systematic variations, principally in the precipitation data.

The time series contain not only systematic variations of different periods and

trend and irregular variations. Using the methods presented in the technical report

it is possible to separate these factors and their significance. However, the accuracy

primarily depends upon the length of the data series. The data series must be for a

period at least double to the systematic variation expected to be present in the

data. That is, if we expect a 60-year cycle, we need minimum of 120 years data

series. Such data series are available only at few selected locations. For India,

Parthasarathy, et al. (1995) presented precipitation data series at monthly, seasonal

and annual for the period 1871 to 1994 for All-India, five homogeneous regions

and 29 meteorological sub-divisions on the basis of a fixed and well-distributed

network of 306 rain-gauge stations by proper area-weightage. Similarly, all over

the world such data series were presented by respective meteorological services /


researchers. Figure 6l presents standardized time series of rainfall anomalies for

the twentieth century (top) and a century period of the GFDL model simulation

containing the most prominent dry episode (bottom).

Climate change traditionally refers to those present in the climate itself,

known as natural changes, known as Natural Rhythm. The natural changes are

beyond man’s control. The natural variations have two components, namely irregular

variations and systematic variations. Irregular variations vary with time – day-to-

day, season-to-season, year-to-year, etc. The systematic variations are also known

as “climatic cycles” or natural rhythm or fluctuations. This part of the climate is

generally referred to as “climate change”.

Climatic cycles in annual or seasonal rainfall means, it shows above the

average pattern for some continuous years followed by about the same number of

years of below the average rainfall pattern and this repeats itself with the time as

was the case with astrological cycles and sunspot cycle. In temperature we call

such cycles of longer duration as ice ages, etc. Where such cycles are present the

“normals” have no meaning. However, the series are affected by localized disturbances

like wars or man induced ecological changes that are known as trend.


WMO (1966) presented details on the method of estimating the systematic

variations or cycles (amplitude & angle) in precipitation data. Blackman & Tukey

(1958) power spectrum analysis, Moving average technique, Iterative auto-regression

technique, Sine curves matching technique, etc. For power spectrum analysis, the

primary data needed for the study are the continuous long series annual or seasonal

data at least twice the length of the expected long cycle. This technique was

widely used in the estimation of cycles in precipitation data. Some of these

procedures could also be used in the case of temperature to deduce the shorter

cycles. In the case of temperature, the concept of ice ages is deduced through the

paleoclimatological tools.

Results: Using the moving average technique, Reddy (1977) observed 52-year

cycle in the dates of onset of Southwest Monsoon observed data over Kerala

Coast in India. This is given in Figure 6m. The average date is 1st June. The top

figure presents the association of lower stratospheric 50 mb winds over Singapore

in relation to onset on monsoon in India. When the winds were easterlies at 50 mb

in the month of May, the onset will be late in that year and when the winds are

westerlies the onset will be early in that year. The winds at 50 mb level over

Singapore are very systematic. In the case of westerly regime, it is always – 12


months and 24 months and the easterly regime, it is always 12 months and 6

months. This pattern makes it easy to predict the onset date over Kerala Coast in

advance. This was presented in the figure by dotted lines and found to be correct.

In fact, Reddy made the study using the data of 100, 50 & mb levels wind at

Singapore, Bogota, Malakal and Lima but found that the onset dates are following

the 50 mb winds over Singapore only and the wind at other locations including

100 mb winds at Singapore haven’t presented any relation with the dates of

onset. Kane (1995) used different data sets (a) derived data sets of onset dates of

Southwest Monsoon over Kerala Coast and (b) average 50 mb winds of Balboa,

Singapore and Gam and did not found relationship as was observed by the author

with the data other than Singapore. That is, it is important to follow trial & error

approach to get a better match.

Using the power spectrum analysis Reddy (1984) tried to homogenize the

climate of northeast Brazil. In this study used 70-years annual precipitation data

series of 105 stations. Based on the results the study zone is divided into three

groups, namely zones less than 4 degrees south latitude, between 4 to 8 degrees

and more than 8 degrees. In all the three zones harmonics 0, 1 and 2 are significant

at many locations. Harmonics 4 & 5, 9-12 and 13-15 are significant at many

stations in the first two zones. The harmonic 16-25 (QBO) is mainly significant in

the last zone. The auto-regression analysis of 133-year data series (1849-1981) of

Fortaleza in the first zone revealed four significant cycles, namely 52-year cycle

along with sub-multiples, namely 26, 13 and 6.5 years. The first three cycles are

closer to harmonics 1, 2 and 4, while the 4th cycle is not significantly seen in the

spectrum analysis, which is slightly different from harmonic 9-12. Through the

iterative regression analysis the amplitudes and phase angles for the four cycles

were derived (Table 6).

Table 6: Estimated amplitudes and phase angles of four cycles in

Fortaleza rainfall data series

Cycle (years) Amplitude Angle (degrees)

52.0 0.1875 6.923

26.0 0.3125 318.462

13.0 0.3125 110.769

6.5 0.1875 0.000

Note: Normalized amplitude presents the deviations from the average as a ratio of

average; the phase angle corresponds to 1911 at Fortaleza.

It is seen from the table that the amplitudes of cycles 26 & 13 years are

higher than those of 52 and 6.5 years cycles. Strang in 1979 reported a 13-year

cycle; Girardi in 1983 reported 26-year cycle; Carlos and co-authors in 1982 found

cycles 26 and 13 years as significant. However, they stated that these two cycles

explained only 24% of variance in the data series. The 52 year cycle found in

onset dates over a low latitude Kerala Coast in India on the Northern Hemisphere

lags behind the 52 year cycle observed in Fortaleza rainfall data series at lower

latitude in Southern Hemisphere.


The integrated pattern along with observed data series of Fortaleza is

presented in Figure 6n(bottom curve), in which the observed and predicted patterns

present a perfect match. This pattern is also seen in the first two zones. The

matching is poor in the last zone. Few locations present good agreement between


observed and predicted curves prior to 1920’s and later 1955’s. There is discrepancy

during 1920-1955. Similar to Fortaleza pattern is also evident in the precipitation

average of 12 locations in Rio Grande do Norte [top curve — right) while top curve

— left depicts the rainfall pattern of two groups of locations in Piaui region in

which during 1920-1955 the two groups presented opposite behavior.

Using similar analysis (Reddy & Singh, 1981) of the annual rainfall data of

Mahalapye in Botswana observed 60-year cycle with sub-multiples of 30, 20 & 10

years. The integrated estimate along with the observed time series is presented in

Figure 6o.

Reddy (1986) studied the precipitation data series of 16 stations in

Mozambique in Southern Hemisphere. In this analysis also included one station

each from Malawi (Chileka) & Zimbabwe (Salisbury) and Lilongwe. The analysis

was carried out using iterative regression approach. The annual rainfall time series

of Catuane (southern most point in Mozambique) presented a 54-year cycle along

with a sub-multiple of 18-year cycle. The integrated pattern along with the observed

time series is presented in Figure 6p. Table 7 presents estimated amplitude and

phase angles. Similar pattern is observed in majority of the stations. However they

present coast to inland & latitude change in the starting year of the integrated


cycle. At the same latitude the starting year is early in coastal stations compared

to inland stations and early in lower latitudes. Nampula, Mutuali, Ulongoe &

Chileka, Lylongwe around the same latitude zone present 40-year cycle with the

starting year respectively showing sharp delay. That is at Nampula it started in

1973 and at Lylongwe it started in 2004. This is longitudinal variation.

Table 7: Estimated amplitudes and phase angles of Durban &

Catuane rainfall data series

Catuane Durban

Cycle Amplitude Phase Cycle Amplitude Phase

(years) (mm) angle (years) (mm) angle

(degrees) (degrees)

54 200 86.7 66 250 185.5

18 200 100.0 22 350 180.0

Reddy & Mersha (1990) analyzed the annual precipitation data of Ethiopia

in Northern Hemisphere. Annual rainfall data was available at 18 locations for more

than 25 years in Ethiopia. Only at three stations the series are for more than 50

years. The 18 stations data series were subjected to iterative regression approach

– sine curve fitting. The results are grouped under 8 types. The longest cycle of

54 years was noted in Koka data series located at a latitude of 8025’ North and

the shortest of 22 years was noted at Asmara at a latitude 150 17’ North while at

Addis Ababa and Massawa with longest series presented irregular pattern. It was

noted that in general the low-lying areas have a shorter periodicity compared to


elevated areas. Mayole at 30 31’ North latitude presented 40-year cycle, similar to

that seen in Mozambique data in the Southern Hemisphere. At seven stations in

between 7.5 to 11.0 degrees North present 36 year cycle. However, there are

differences in the starting years of above average pattern. Four locations presented

28-year cycle. Figure 6q presents these patterns for four locations, namely In the

case of Gore & Jijiga the prominent cycles are 36 & 28-years; for Mayole & Asmara

[now it is in Eritria] they are 40 & 22-years. Tyson (1978) studied the Durban in

South Africa annual rainfall data and noted 66 and 22-year cycles. Table 7 presents

the amplitude and phase angles of the cycles noted in Durban along with Catuane

rainfall series.

Reddy (2000a) studied the All-India Southwest Monsoon Rainfall series and

the rainfall series for three meteorological sub-divisions in Andhra Pradesh using

the data series presented by Parthasarathy, et al. (1995) for the period 1871 to

1994. The All-India Southwest Monsoon Rainfall series presented a 60-year cycle

(Figure 6s) — The bottom diagram refers to annual march of rainfall and the top

diagram refers to the march of 10-year rainfall totals. In the above the average 30-

year part of the cycle present deficit rainfall (i.e., less than 90% of average) in 2 to

3 years while the same during the below the average 30-year part of the cycle are 6

to 10 years. The current ongoing above the average cycle commenced during 1991

is predicted to continue upto 2020. So far the rainfall was normal or above

normal.

The agroclimatic variable (G = available effective rainy period, weeks; S =

starting week number of planting rains – starting time of G] time series of Kurnool

in Andhra Pradesh presented a 54-year cycle. Using this pattern the rainfall data

series of the three meteorological sub-divisions in Andhra Pradesh were analyzed

and found they follow this pattern in the case of Southwest Monsoon (SWM)

rainfall data series and a reverse pattern in the case of Northeast Monsoon (NEM)

rainfall data series [Figure 6t]. The bottom diagram refers to the SWM & NEM

cyclic pattern in which given the % number of years the rainfall of the individual

years are less than the average in each 28-year period. The top diagram presents

the pattern of agroclimatic variables (G & S) pattern of Kurnool. The 54 and its’

sub-multiple like 28 years cycle are also present in the Mozambique & Ethiopia

precipitation data series.

These results clearly demonstrate one thing that the precipitation data follow

rhythmic patterns in terms of cycles & their sub-multiples. It appears in certain

conditions all these are clearly seen but under certain other conditions either cycle

or its’ sub-multiple is clearly seen. These fluctuations are observed in both the

Southern & the Northern Hemisphere precipitation data series. 66-years cycle is

the longest cycle observed at higher latitude zone and 22-years cycle is the shortest

cycle observed at lower latitude zone. In between, the important cycles observed

are 60, 56,54, 52, 40, 36, 28-years cycles. By using the data accumulated in the

last three decades, these results could be updated and could be integrated in

terms of latitude-longitude; land-sea; sun-weather. We must look this in terms of

global weather patterns – summer rains, winter rains, summer & winter rains (bi-


model rainfall) — but not in isolation and then only we can achieve reasonably

good conclusions that help planning in any country or region.


Chapter 7

Ecological Change

7.1 What is Ecological Change?

In addition to changes in the atmosphere’s composition, changes in the

land surface & cover, known as ecological changes, can have important effects on

climate. For example, a change in land use and cover can affect temperature by

changing how much solar radiation the land reflects and absorbs. Processes such

as deforestation, reforestation, desertification, changes in topography/orography,

urbanization, agriculture – dry-land to wet-land & vice versa or grazing lands,

water resources – construction of dams, etc contribute to changes in temperature,

wind, precipitation, etc in places they occur.

Changes in land cover and land use can also affect the amount of carbon

dioxide and other greenhouse gases taken up or released by the land surface and

can have significant effects on radiative forcings and thus the climate at the local

& regional level by changing the reflectivity of land surface known as albedo

factor, formation of thermal inversions, etc.

To understand global land-cover change as an element of global environmental

change, it will be necessary to specify the links between human systems generating

changes both in land use and in the physical systems that are affected by the

resulting changes in land covers. The environmental consequences of uses of land

cover (changes in the state of cover) affect the original driving forces through the

environmental impacts feedback loop. Likewise these land-cover changes can be

repeated elsewhere such that they reach a global magnitude that trigger climate

change, which in turn feeds back on the local physical system, affecting land

cover and ultimately the driving forces through the environmental impact loop.

Regardless of the stimuli - local or global environmental impacts or the interactions

of driving forces in their social context - changes in driving forces at any given

time may trigger a new land use, with new consequences for the land-use/cover

system. This perspective indicates that understanding of global environmental

change must consider the conditions and changes in land cover engendered by

changes in land use; the rates of change in the conversion-modification-maintenance

processes of use; and the human forces and societal conditions that influence the

kinds and rates of the processes.

Land use is obviously constrained by environmental factors such as soil

characteristics, climate, topography, and vegetation. But it also reflects the

importance of land as a key and finite resource for most human activities including

agriculture, industry, roads including railways, forestry, energy production,

settlement, recreation, and water catchment and storage. Land is a fundamental

factor of production, and through much of the course of human history, it has

been tightly coupled to economic growth. As a result, control over land and its

use is often an object of intense human interactions.


Human activities that make use of, and hence change or maintain, attribute of

land cover are considered to be the proximate sources of change. They range from

the initial conversion of natural forest into cropland to on-going grassland

management (e.g., determining the intensity of grazing and fire frequency). Such

actions arise as a consequence of a very wide range of social objectives, including

the need for food, fibre, living space, and recreation; they therefore cannot be

understood independent of the underlying driving forces that motivate and constrain

production and consumption.

Some of these, such as property rights and the structures of power from the

local to the international level, influence access to or control over land resources.

Others, such as population density and the level of economic and social development,

affect the demands that will be placed on the land, while technology influences

the intensity of exploitation that is possible. Still others, such as agricultural pricing

policies, shape land-use decisions by creating the incentives that motivate individual

decision makers. Interpretations of how these factors interact to produce different

uses of the land in different environmental, historical, and social contexts are

controversial in both policymaking and scholarly settings. Furthermore, there are

many theories regarding which factors are the most important determinants.

Particular controversy arises in assessing the relative importance of the different

forces underlying land-use decisions in specific cases. For example, apparent dry-

land degradation could be the result of: overgrazing by increasingly numerous

groups of nomadic cattle herders; an unintended consequence of a “development”

intervention such as the drilling of bore holes which increases stress on land close

to the wells; or the political clout of groups that, through governmental connections,

are able to over-exploit land belonging to the state or local communities. Identifying

a particular cause may have implications for the rights of competing user groups

or the formulation of policy responses.

There are several possible forces driving land-use and land-cover changes. In

other words it relates to population & their lifestyle. Population density found to

be related to agricultural expansion and intensification everywhere, but only in

some regions to deforestation. The interactions of population, affluence, and

technology as causes of environmental change have been explored extensively, but

research on the direct association of affluence or technology with land use change

is not as common. This is because of the paucity of globally comparative data for

statistical assessments and because of the common assumption that level of

affluence or technology do not by themselves govern human-environment

relationships but must be considered within a larger set of contextual variables.

Nonetheless, some historical assessments associate high levels of affluence and

industrial development (and thus the ability to draw resources from elsewhere)

with the return of forest cover.

Global comparisons indicate that afforestation is largely a phenomenon of

advanced industrial societies, which are both affluent and have high technological

capacity. Wealth, however, also increases per capita consumption, bringing about

environmental change through higher resource demands, although these higher


demands can be reduced by advanced technologies available to wealthy societies.

Poverty is often associated with environmental degradation, although recent research

shows that this relationship is strongly influenced by other factors as well. These

mixed conclusions indicate the importance of further studies of the relationship

between level of affluence and environmental change. It is obvious that technological

development alters the usefulness and demand for different natural resources. The

extension of basic transport infrastructure such as roads, railways, and airports,

can open up previously inaccessible resources and lead to their exploitation and

degradation. To these added further (i) political economy, which includes the

systems of exchange, ownership, and control; (ii) political structure, involving the

institutions and organization of governance; and (iii) attitudes and values of

individuals and groups. Changes in attitudes and values may add a dimension to

environmental change that cannot be explained otherwise, such as impact on land

use of the “green” movement. Improved transport facilities are expected to exacerbate

land degradation if the region in question is small, but its impact on larger regions

will vary by circumstance. Additional comparative studies are needed to address

the interactions of different driving forces with their environmental context.

However, the specific role of any of the proposed driving forces is extremely difficult

to demonstrate at this global scale of analysis, however, because of their complex

interrelationships, and interactions with other factors such as social organization,

attitudes, and values, which have also undergone profound changes. As a result,

research is driven by subjective interpretations and assumptions rather than by

attempts to test different hypotheses at global level. Most of the components

have direct and indirect impacts on climate related changes. In some cases the

indirect effects more dangerous over the direct impacts. Though the individual

components impact is felt globally, the impact at local, regional and national level

they are large. Certain components may be significantly felt in some countries

and few others in other countries. Because of this, the impact of ecological

changes on climate made complex.

7.2 Population & Lifestyle related Changes

Let us look at changes in population & lifestyle with an example of US [from

a publication of Population Reference Bureau, 2006 – Lifestyle choices affect US,

impact on the Environment, by Sandra Yin —]. Between 1950 and 2005, US

population nearly doubled and in many cases, the consumption of resources is

more than doubled. For example, (a) overall energy consumption nearly tripled.

Petroleum consumption within the transportation sector rose more than 300%

between 1950 and 2005; (b) Wood consumption was up by 171% between 1950

and 2002; (c) Coal consumption increased by 128% from 1950 to 2005; and (d)

Water use was up by 127% between 1950 and 2000. The US population reaching

300 million might not be seen relevant at a global level. After all, the US represents

just 5% of the world population. But it consumes disproportionately larger amounts

than any other nation in the world – at least one-quarter of practically every

natural resource, because of its’ lifestyle choice. The high consumption tends to

occur in households in the highest income quintiles. For example, households in


the top-income bracket own on an average 2.8 vehicles and this number progressively

drops in lower household-income groups. That is, how we live spatially affects

other consumption patterns.

In recent decades, “sprawl” has become the most common-land use pattern

that refers to low-density residential-subdivisions, commercial strips, large retail

complexes surrounded by acres of parking and office parks far from home and

shops, and a growing network of roads to link them. This is probably the most

consumptive housing pattern. Sprawl translates into longer drive to connect home

with work, school, and recreation. Not surprisingly, US’s annual number of vehicle

miles traveled in 2004 was nearly 6.5 times the number in 1950. As dependency

on cars grows, fuel consumption rises exponentially and more stop-and-go driving

results in less fuel efficiency and more pollution. The share of workers who drove

top work alone rose from 64% to 76% between 1980 and 2000. During that same

period, the share that carpool fell from 20% to 12%. The US has fewer people

than India & China, but motor vehicles per 1000 are more common in US

(Table 8).

Table 8: Estimated number of vehicles vs population

Country P N Estimated No. of motor vehicles

India 1.122 9 10,098,000

China 1.311 12 15,732,000

US 0.300 779 233,700,000

Note: P = Population in 2006 in billions; N = No. of motor vehicles per 1000

people.

Even as US passes the 300-million mark, American’s use 75% more water

per capita than the average person in the world’s developed nations [US with 1682

cubic meters of water per person; 956 for developed countries & 545 for developing

countries). This tendency is clearly evident in developing countries too in addition

to developed countries.

7.3 Forest Related Land Use Changes

Forests cover about 30% of the global total land area; this amounts to just

under 40 million km2, but it is unevenly distributed. Deforestation, mainly conversion

of forests to agricultural land, is continuing at an alarmingly high rate. Forest area

decreased worldwide by 0.22% per year in the period 1990-2000 and 0.18% per

year between 2000 and 2005. However, the net loss of forest is slowing down as a

result of the planting of new forests and of natural expansion of forests. Primary

forests account for over a third of global forest area, but 60 000 km2 (an area

roughly the size of Ireland) continue to be lost or modified by logging or other

human interventions each year. Forest plantations are increasing but make up less

than 5% of overall forest area. The remainder are mainly modified natural forests,

but also semi-natural forests.


The world’s natural forests are experiencing land use change due to both

direct and indirect causes. Direct causes include immediate human land use activities

that change forest cover in a local area. Key drivers include agricultural expansion,

infrastructure development, wood extraction, climate change, fire and alien invasive

species. Underlying causes result from social and institutional processes that may

indirectly impact forest cover from a local, national, or international level. Prominent

underlying causes include market failure and perverse incentives, corruption,

inappropriate state policies and institutional failure, population pressure and poverty.

The most significant human-related, direct causes affecting forest cover are discussed

below.

Agricultural expansion: Over the years, researchers have identified agricultural

expansion as a major factor in almost all studies on deforestation. In the 1990s,

according to the United Nations Environment Programme (UNEP), 70% of total

deforested areas were converted to permanent agriculture systems. Despite the

compelling figure, regional differences should be noted. For example, in Latin America

conversion to agriculture has been large scale and permanent whereas in Africa

small-scale agricultural enterprises have predominated. In Asia, the changes have

been more equally distributed between permanent agriculture and areas under

shifting cultivation. Historically, increases in food production have been at the

expense of millions of hectares of forest. Humans have always cleared land for

agriculture either for subsistence or for larger scale settling and planting. The FAO

claims that former is less a threat to forests than the latter.

Infrastructure development: The conversion of forestland to infrastructure

development can take several forms, including road-building, hydroelectric dam

construction, etc. Road construction reduces forest cover both directly by occupying

land, and indirectly, by fragmenting the landscape and opening it up for exploitation.

A study showed that 86% of Amazonian forests lost between 1991 and 1996 were

within 25 km of major roads. A similar process has occurred in Indonesia and

Central Africa. Dam construction is an infrastructure development mostly affecting

forests in Southeast and East Asia. Dams flood large populated areas, forcing

migration or resettlement to more environmentally sensitive areas. This is turn lead

to deforestation, degradation of forests and increased erosion. However, unlike

roads dams have a compensating affect by increasing water spread area and greenery

for a long time period over large tracts.

Wood extraction: Another direct cause of forest land-use change is wood

extraction from natural forests. Despite the growing importance of plantations as

a source of wood supply, wood extraction in the form of commercial timber, poles,

fuel wood, and charcoal continues to degrade mature natural forests in many

parts of the world. In the case of commercial logging, tree removal methods are

frequently destructive and unsustainable. This is often the case on steep slopes

and in sensitive ecosystems such as mangroves. Also, though many tropical countries

in Africa, Asia and Latin America rely on logging timber for export earnings. However,

under this reforestation is common.


Harvesting forests for timber: Harvesting is an important factor in the global loss

of forest cover but it often causes degradation rather than deforestation, as old

growth is replaced with younger ecosystems or fewer species, or as areas are only

partially logged. The extent of forest cover is most threatened when farmers,

ranchers and fuel wood collectors move in to clear the land for other economic

uses after harvesting is complete. According to the FAO (FRA 2000), timber harvesting

takes place on some 110,000 km2 of tropical forests each year.

Harvesting forests for pulp and paper production: Paper manufacture accounts for

some 14% of the total world wood harvest. Most of the fibre used for pulp comes

from managed temperate forests (only 2% from natural hardwood or tropical

forests). The IIED in their study on “The Sustainable Paper Cycle” found that the

sources of wood fibre mainly originate from managed natural regeneration forests

(37%), plantations (29%) and thirdly from unmanaged natural regeneration forests

(17%). Original conifer forest account for 15% while tropical rainforests and

hardwood forests account for only 2% of the global wood pulp. Europe, North

America and Japan are increasingly using recycled paper as a source of fibre.

Acid rain and atmospheric pollutants: The most common form of atmospheric

pollution believed to affect forests is ‘acid rain,’ defined as precipitation containing

high levels of sulfuric or nitric acid. Acid rain and air pollution degrade forest

vegetation. Damage varies with tree species and soil composition. Research in

Eastern Europe, where in the past severe atmospheric pollution took place, is

clarifying the links between this pollution and forest vegetation. Forests seem to

recover well from mild pollution damage but more slowly with severe damage.

Research on forest recovery is under way in an area of the Czech republic where

50% of the forest died in 1989 due to atmospheric pollution. On the other hand,

there is evidence that carbon dioxide in the atmosphere increases the growth rate

of forests. Radiation is another form of pollution. According to the University of

Voronezh in Russia, 70,000 km2 of forest in Russia, Belarus and Ukraine were

degraded by the nuclear accident in Chernobyl.

Loss of forests to fire: Fires are a key driver of forest land-use change. A United

Nations Environment Programme (UNEP) study estimates that annually fires burn

up to 500 million hectares of woodland, open forests, tropical and sub-tropical

savannas, 10-15 million hectares of boreal and temperate forest and 20-40 million

hectares of tropical forests. Yet, fire is a paradox as while it can cause extensive

ecological, economic, and social damage it can also be extremely beneficial through

nutrient recycling and regeneration. For example in boreal forests, fire is a natural

part of the forest cycle with some tree species, notably Lodge pole Pine and Jack

Pine being able to germinate only after they have been exposed to fire. In addition,

burning quickly decomposes organic matter into mineral components that cause a

spurt of plant growth, and can also reduce disease in the forest. Nevertheless,

forest fires in contrast have caused considerable environmental, health, economic

and social damages in recent years and have been recognized as major cause of

forest loss and degradation in some parts of the world. Furthermore, emissions

from forest fires have also exacerbated global climate change.


Human activities can start fires deliberately or accidentally. These accidents

can be caused by careless use of fire for the clearing of land or other purposes.

They can burn out of control for long periods of time. Burned areas can recover but

they are vulnerable because fires open up large areas of forest and the ash increases

the fertility of the soil, thereby giving an incentive to agricultural use. Areas of

concern include the Mediterranean forests, tropical forests and boreal forests in

northern China and Siberia. A prominent example of deforestation by fire is the

case in1997-1998 in Sumatra and Borneo (Indonesia). Although there was wide

disagreement at first, the final consensus is that 20,000 km2 of land had burned,

only some of it being forest.

Conversion of forests for expansion of cash crops production in developing

countries: Many developing countries have large debts requiring foreign ‘hard’

currency to pay the interest. The incentive is then to convert forests to expand the

production of export crops such as palm oil, rubber or coffee. Sometimes economic

policies, such as Structural Adjustment Policies (SAPs) that are meant to address

economic crises, may encourage faster exploitation of resources such as forests

and fisheries. In many cases, economic policies are followed but clauses calling for

the protection of natural resources are ignored.

Destruction of forests in the course of warfare: Warfare can lead to long-lasting

deforestation. Forest fires can be set off in a battle, deliberately or not. The Vietnam

War can be cited, but also conflicts in Myanmar (Burma) and Sri Lanka.

Alien invasive species: As the global movement of people and products spreads, so

does the movement of plant and animal species from one part of the world to

another. When a species is introduced into a new habitat – for example, oil palm

from Africa into Indonesia, Eucalyptus species from Australia into California, and

rubber from Brazil into Malaysia – the alien species typically requires human

intervention to survive and reproduce. Often these alien species are economically

important and enhance the production of forest commodities in many parts of the

world. However, in some cases species introduced intentionally become established

in the wild and spread at the expense of native species, affecting entire ecosystems.

Perhaps even worse are invasive alien species that are introduced unintentionally,

such as disease organisms that can devastate an entire tree species (e.g. Dutch

elm disease and chestnut blight in North America) or pests that can have a major

effect on native forests or plantations (e.g. gypsy moths and long-horned beetles).

As global trade grows, so does the threat from devastating invasive species of

insect and pathogen. These could fundamentally alter natural forests and wipe

out tree plantations, the latter being especially vulnerable because of their lower

species diversity.

Absence of Good Governance and Rule of Law: Government policies, and how

those policies are enforced, both within and outside the forest sector, also ultimately

impact on forestland use change. Forestland is still all too often seen as a nationally

owned asset, irrespective of the stewardship that local communities have exercised

over the same resource for many years. Inequities in titling and use rights can


result in forests becoming a major source of conflict and/or illegal activity. While

illegal logging and corruption may, and often does, exist because of pure criminality

it can, in some situations, be driven by inappropriate governance structures that

turn legitimate concerns or entitlements into illegal activities. For example, in one

Central American country in the early 1990s one of the main causes for bribery

associated with log transport permits was not that loggers want to move illegally

harvested trees but rather that they wanted to avoid long bureaucratic delays in

attaining permission that would leave legally harvested trees deteriorating in forest

loading yards.

7.4 Agriculture related Land Use Changes

Agriculture refers to the production of goods through the growing of plants,

animals and other life forms. The history of agriculture is a central element of

human history, as agricultural progress has been a crucial factor in worldwide

socio-economic changes. Weather-building and militaristic specializations rarely

seen in hunter-gatherer cultures are commonplace in agricultural and agro-industrial

societies—when farmers became capable of producing food beyond the needs of

their own families. It is argued that the development of civilization required

agriculture. As of 2006, an estimated 45 percent of the world’s workers are employed

in agriculture (from 42% in 1996). This has got both direct and indirect affects.

The indirect effects have more environmental consequences.

As of late 2007, several factors have pushed up the price of grain used to

feed poultry and dairy cows and other cattle, causing higher prices of wheat (up

58%), soybean (up 32%), and maize (up 11%) over the year. Approximately 40%

of the world’s agricultural land is seriously degraded. In Africa, if current trends of

soil degradation continue, the continent might be able to feed just 25% of its

population by 2025, according to UNU’s Ghana-based Institute for Natural Resources

in Africa.

According to the United Nations, the livestock sector (primarily cows,

chickens, and pigs) emerges as one of the top two or three most significant

contributors to our most serious environmental problems, at every scale from local

to global. Livestock production occupies 70% of all land used for agriculture, or

30% of the land surface of the planet. It is one of the largest sources of greenhouse

gases—responsible for 18% of the world’s greenhouse gas emissions as measured

in CO2 equivalents. By comparison, all transportation emits 13.5% of the CO

2. It

produces 65% of human-related nitrous oxide (which has 296 times the global

warming potential of CO2) and 37% of all human-induced methane (which is 23

times as warming as CO2). It also generates 64% of the ammonia, which contributes

to acid rain and acidification of ecosystems. But studies have shown that a cow is

climate neutral since it eats grass, corn. These plants take the CO2 out of the air.

To meet the food needs of ever increasing population around 60’s green

revolution technology was introduced in the system. The production is primarily

related to water availability and chemical inputs. The water availability was related

to tanks built by rulers of the day. Then open wells, then bore wells and small &


big dams. According to a report of the World Commission on Dams, there are

around 50,000 dams around the world of which 45% are in China, 14% are in

USA, 9% are in India, 6% in Japan, 3% in Spain, the rest in 23%. After this

accounting, China built the largest dam (Three Gorges). With this system changed

the crops & cropping pattern; multiple cropping to sole crop; dry land to wet land

agriculture. With dams, forests are submerged and water spread has increased.

Thus, land use changed in multifold.

To produce chemical inputs, industries were established that introduced

greenhouse gases into the atmosphere. They introduced mining for raw material

used in these industries. Thus, land use changed. For lift irrigation, power is used;

and in the power production again contributing greenhouse gases. These industries

induced severe health hazards on life forms. The food produced under the green

revolution technology is polluted and as a result health hazards. This introduced

industries to produce medicine that are causing severe pollution to air, water &

soil; causing soil degradation. The vicious circle became a never- ending

phenomenon. In affect the agriculture changed the land-use & land cover in terms

of crops/cropping pattern and water reservoirs on the one hand; and at the same

time introduced greenhouse gases and health hazards to life forms on the Earth

and they in turn introduced green house gases. The land use changes here contribute

changes in net radiation as well atmospheric water vapour balance and advection

of energy. However, not much work has been done in this direction. Thus only

qualitative statements and no quantitative estimates are available at global level.

7.5 Urbanization related Land Use Changes

Metropolitan areas around the globe irrespective of developed or developing

nations are growing at unprecedented rates, creating extensive urban landscapes.

Many of the farmlands, wetlands, forests, and deserts have been transformed

during the past 100 years into human settlements, known as “concrete jungle”.

Almost every one has seen these changes to their local environment but without a

clear understanding of their impacts on environment and life forms. It is not until

we study these landscapes from a spatial and temporal perspective that we can

measure the changes that have occurred and predict the impact of changes to

come.

Most major metropolitan areas face the growing problems of urban sprawl,

loss of natural vegetation and open spaces as well water bodies and converting

these into concrete structures in both horizontal-vertical spectrum with roads.

The public identifies with these problems when they see residential and commercial

development replacing undeveloped land around them. Urban growth rates show

no signs of slowing, especially when viewed at the global scale, since these problems

can be generally attributed to increasing population. Cities have changed from

small, isolated population centers to large, interconnected economic, physical,

and environmental features.

Urban growth and the concentration of people in urban areas are creating

societal problems worldwide. One hundred years ago, approximately 15 percent of


the world’s population was living in urban areas. Today, the percentage is nearly

50. In the last 200 years, world population has increased six times, stressing

ecological and societal systems. Over the same time period, the urban population

has increased 100 times; concentrating more people on less land even as the total

land devoted to urbanization expands. Yet the temporal and spatial dimensions of

the land use changes that shape urbanization are little know, even in the United

States. A temporal database can be visualized as a sequence of maps, such as

those presented in Figures 7a, b, c & d — examples of urban growth in Willamette

Valley, Chicago-Milwaukee, Washington, D.C. & River watershed —. Sequential

maps show urbanization as a static pattern that changes with each time period

that is mapped:

Figures 7a presents an example of urban change for Chicago-Milwaukee in

1955, 1975 & 1995. Each time period is represented by a different color. Black

shows the extent of urban growth in 1955, red represents 1975, and yellow

represents 1995. Figures 7b presents the time series documents of urban change

in the Willamette Valley region over 115 years. The red areas represent urban extent

for each time period. The Pacific Ocean and the Columbia River are shown in blue.

Figures 7c presents the series of maps shows more than 200 years of urban growth

in and around the Washington, D.C. area. The red areas represent urban extent

for each time period and the blue is Chesapeake Bay. This figure also includes a

projection for 2025 period given in yellow & green colours. Figures 7d presents

series of maps compares changes in urban, agricultural, and forested lands in the

Patuxent River watershed over the past 140 years. Red colour shows the extent of

urbanization, gold shows extent of agriculture & green shows the extent of forestland.

The existence and accessibility of transportation routes have often dictated

patterns of urban growth. Urban areas that were established in the 18th and early

19th Centuries were usually located along waterways, reflecting dependence on

shipping for the transportation of goods and people. By the middle of the 19th

Century, railroads began to connect existing towns and spurred the growth of new

urban areas. The post-World War II era saw not only an increase in the population

of most metropolitan areas, but also the emergence of a society dependent on the

automobile. The proliferation of the private automobile led to expansive

development at the edges of many urban areas. The development of the Interstate

Highway system in the 1950’s spurred the widespread construction of roads. As

road networks expanded and became more complex, urban development followed.

As in the past, most recent urban growth has occurred along transportation

corridors.

These introduced changes in the net radiation balance as well atmospheric

water vapour balance along with greenhouse gases composition. These are assessed

qualitatively but there is no quantitative data at global level.

7.6 Mining related Land Use Changes

Mining related land use change has direct and indirect impacts on

environment. This is a phenomenon encompassing the whole world. However,


the degree and intensity vary with country-to-country, location-to-location

depending up on the prevailing natural geology, vegetative & orography conditions.

Gold, copper, diamonds, and other precious metals and gemstones are important

resources that are found in rainforests around the world. Extracting these natural

resources is frequently a destructive activity that damages the rainforest ecosystem

and causes problems for people living nearby and downstream from mining

operations. In the Amazon rainforest most mining today revolves around alluvial

gold deposits. Due to the meandering nature of Amazon Rivers, gold is found

both in river channels and on the floodplains where rivers once ran. Large-scale

operators and informal small-scale miners actively mine these deposits. Both

operators rely heavily on hydraulic mining techniques, blasting away at riverbanks,

clearing floodplain forests, and using heavy machinery to expose potential gold-

yielding gravel deposits. Large-scale mining operations, especially those using

open-pit mining techniques, can result in significant deforestation through forest

clearing and the construction of roads which open remote forest areas to transient

settlers, land speculators, and small-scale miners.

There are several other types of mines, namely coal, granite, raw material

for cement, iron ore, other metals, etc. Some times, forest areas may not be

cleared but this not only causes changes in land use-land cover but introduce

pollutants into the atmosphere. Few general issues relating to mining are given

below:

• The mining dumps appalling amounts of waste into local streams, rendering

downstream waterways and wetlands “unsuitable for aquatic life”;

• Mines disturb large tracts of pristine forests and release harmful toxics,

such as mercury, arsenic, cadmium, chromium and lead into soil and groundwater;

• The toxic runoffs from mines not only disturb local freshwater fish and

wildlife but can also have a damaging effect on humans;

• Long-term exposure to arsenic is linked to skin cancer and other organ tumors,

while cadmium exposure can cause kidney disease. Lead can stunt normal growth

and development in children and some forms of mercury can cause damage to the

nervous system;

• Mining incursions in road less areas are also dependent on constructing a

large network of access roads;

• Road building damages the terrain and after all the resources are extracted,

abandoned mines require more roads and cleanup teams to prevent toxic waste

from damaging the ecosystem;

• Forests are biologically rich with species of amphibians, birds, mammals and

reptiles, and species of vascular plants. Mining affect the balance of these;

• The mining process generates other toxic compounds including oil and fuel

waste and fine suspended particles that affect river navigation and fish populations

by reducing the availability of oxygen;


• Mining further exposes previously buried metal sulfides to atmospheric oxygen

causing their conversion to strong sulfuric acid and metal oxides, which run off

into local waterways. Oxides tend to more soluble in water and contaminate local

rivers with heavy metals;

• Clandestine miners further damage the riparian environment by tearing up

biologically sensitive areas including alluvial zones and small creek beds, key habitats

for aquatic life. In the forest, they clear under story vegetation, while leaving some

canopy trees to prevent patrol helicopters from landing;

• These sites are difficult to locate with plane or helicopter, suggesting that

mining damage may be underestimated;

• Under story clearing can dry the forest, affecting species distribution and

putting it at greater risk to forest fires;

• In abandoned mining areas, cleared forest can take more than 100 years to

re-grow;

• In the meantime, the vegetation shift changes the entire ecology of the

ecosystem, transitioning from closed tropical rainforest to a weedy, less bio-diverse

landscape;

• Beyond the environmental effects, mining has also been linked to the spread

of malaria. The influx of prostitutes into mining camps has increased the incidence

of AIDS and other sexually-transmitted diseases as well. Miners themselves are at

risk.

7.7 Impact on Climate

When humans transform land from forests to seasonal crops or from natural

to urban environments, the regional climate system is altered. For example, clear-

cut hillsides are significantly warmer than forests. Urban environments are also

islands of heat produced by industry, homes, automobiles, and by asphalt’s

absorption of solar energy. Changing uses of the land are also associated with

changes in the usage and availability of water, as well as the production of GHGs.

Deforestation can significantly increase the amount of atmospheric CO2. All these

land use changes on a contiguous plot-form are likely to have a large, direct effect

on global average temperature as well local & regional weather & climate in a

complex way.

Land use and land cover affect the global climate system through bio-

geophysical, bio-geochemical, and energy exchange processes. Variations in these

processes due to land-use and land-cover change in turn affect local, regional, and

global climate patterns. Key processes include uptake and release of GHGs by the

terrestrial bio-sphere through photosynthesis, respiration, and evapotranspiration;

the release of aerosols and particulates from surface land-cover perturbations;

variations in the exchange of sensible heat between the surface and atmosphere

due to land-cover changes; variations in absorption and reflectance of radiation as

land-cover changes affect surface reflectance; and surface roughness effects on


atmospheric momentum that are land-cover dependent. Human activity can and

does alter many of these processes and attributes, but weather and climate, as

well as geological and other natural processes, are also important.

For example, land-cover changes such as deforestation and forest fires alter

ecosystems cause short-term release of carbon dioxide, methane, carbon monoxide,

and aerosols to the atmosphere and as well as cause long-term change in the

reflectivity of the land surface, which in turn determines how much of the Sun’s

energy is absorbed and thus available as heat, while vegetation transpiration and

surface hydrology determine how this energy is partitioned into latent and sensible

heat fluxes. At the same time, vegetation and urban structure determine surface

roughness and thus air momentum and heat transport.

Understanding the significance of land-cover changes for climate,

biogeochemistry, or ecological complexity is not possible, however, without additional

information on land use. This is because most land-cover change is now driven by

human use and because land-use practices themselves also have major direct effects

on environmental processes and systems. Evaluating the causes and the

consequences of changes in land use and land cover is becoming an urgent need

for more than the academic research community. At the 1992 UN Conference on

Environment and Development, a framework convention on climate change and a

convention on biodiversity were signed, as was a declaration of principles on

forests; while no formal action was taken on desertification, a broad agreement

was reached to work toward a conference and a convention in the near future.

Changes in land use and land cover are significant components of all the problems

addressed by these agreements, yet we do not have enough knowledge about

such phenomena to decide how these conventions should best be structured and

which of their proposed elements are likely to be effective. At present, we are

unable to answer even the most basic questions.

Recognizing the importance of studies of changes in land use and land

cover in developing our understanding of global environmental change, the

International Geosphere-Biosphere Programme (IGBP) and the Human Dimensions

of Global Environmental Change Programme (HDP) formed an ad hoc working

group in early 1991 to investigate the possibilities of a joint effort by natural and

social scientists to study the issue. The group met in New York City with the

assistance of the Social Science Research Council in May 1991 and in Dalaro,

Sweden in October 1991, with support from the Swedish Council for Planning

and Coordination of Research (FRN). Carolyn Malmstrom represented the IGBP

Seaetariat at the New York meeting. Several additional individuals took part in the

working group’s second meeting. The working group recommended that a joint

IGBP-HDP Core Project Planning Committee be established to develop an

interdisciplinary research programme involving social and natural scientists to project

future states of land cover. This recommendation was based on the following

conclusions of the working group: “Understanding the past and future impacts of

changes in land cover is central to the study of global environmental change and

its human driving forces and impacts, including hydrology, the climate system,


biogeochemical cycling, ecological complexity, and land degradation and its impacts

for agriculture and human settlement”. Additional basic research is required to

understand how these factors interact to drive land cover change or how projections

about them could be used to project future patterns of land use, future rates of

land-cover change, and future states of land-cover.

In light of the recommendation of the working group and the importance of

the subject, the Scientific Committee of the IGBP and the Standing Committee of

the HDP decided to establish a joint Core Project Planning Committee (CPPC),

under the joint chairmanship of B L Turner and D L Skole, with responsibility to

develop a detailed scientific plan for an IGBP-HDP project on changes in land use

and land cover. It was further decided to hold an open scientific meeting to review

the scientific plan that will be proposed by the CPPC. Assuming the subsequent

establishment of the project, a Joint Scientific Steering Committee would then be

formed to coordinate its implementation.

7.7.1 Heat Island Effect

Kenneth Chang presented a report in New York Times, which was reproduced

by San Jose Mercury Nes on August 22, 2000 “Urbanites feel the heat when cities

replace trees and greenery with buildings and blacktop”. — Atlanta is so big and

hot that it makes its own weather, and scientists have the pictures to prove it.

While analyzing weather data that had been collected during the 1996 Summer

Olympics, Dr. Robert Bornstein, a professor of meteorology at San Jose State

University, saw a pattern in the winds. The heat absorbing roofs and pavement

were warming the air, and the hot air was rising, sucking air from all directions into

the city (Figure 7e). Bornstein surmised what was happening next: As the warm air

rose, it cooled, condensing into clouds and rain. Satellite images backed him up,

revealing several instances in which thunderstorms erupted over Atlanta, seemingly

out of nowhere, and dumped rain on the city, usually at its southeast and northeast

edges. The idea that cities generate their own heat, and alter their climates as a

result, is not new. Bornstein observed thunderstorms appearing over New York

City more than two decades ago, but in recent years, scientists using high-tech

sensors have produced a more detailed picture of how human activities change

the weather.

Over the past four years, researchers from the NASA Marshall Space Flight

Centre in Huntsville, Al., have flown jets equipped with infrared cameras over Salt

Lake City, Sacramento, Baton Range, La., and Atlanta, producing block-by-block

temperature maps. Figure 7f reveals surface temperatures on a summer day in

1998 in down town Sacramento – blue areas are vegetated and relatively cool, 77

to 86 degrees; red areas are 120 degrees and above. Figure 7g presents the

surface temperatures in downtown Sacramento at 11 a.m. June 30, 1998. Air

temperatures differ, depending on meteorological conditions. The other important

issue in warming of urban areas is the destruction of water bodies. This is an

important issue all over the world. Parks were cool – plants are full of cooling

water, and trees also provide shade – while asphalting lots were hot. . The hottest


buildings often were the newest. In

Salt Lake City, the Scott M. Matheson

Courthouse, a dark-roofed building that

opened a couple of years ago, is a white-

hot splotch in the infrared photograph,

suggesting a roof temperature of about

170 degrees Fahrenheit. Across the

street to the east, the century-old

castle-like City and County Building is

a relative cool reddish color. Figure 7h

presents an example of horizontal

section of heat island. The heat-island

effect is growing with the outward push

of suburbia. Atlanta’s urban heat island

now covers at least 17 square miles.

Luke Howard, an amateur

meteorologist in England, first recorded

the heat-island effect almost 200 years

ago. Beginning in 1807, he started

comparing temperatures from several

sites within London with those

measured a few miles beyond the city’s

edge, and through the years, he noticed

that the city was consistently warmer.

“Thus,” Howard wrote in his book, “The

Climate of London” in

1818,

“under

the varying circumstances of different sites,

different instruments, and different positions of

the latter, we find London always warmer than

the country, the average excess of its temperature

being 1.579 degrees”. Today, the effect is more

noticeable. In the largest cities, average

temperatures can range 5 to 10 degrees Fahrenheit

hotter than surrounding areas. Figure 7i presents

rate of heat island growth in degrees Fahrenheit

per decade over different cities in USA. Similar

studies were carried out all over the world including

in India. Fact Sheet (Down To Earth, March 15,

2008) presents “City centers are physically hotter.

Known as the heat island

effect, urban and suburban

temperatures are 1 to 6 0C


hotter than nearby rural areas, says the US Environmental Protection Agency”.

Globally the meteorological stations, primarily, are located in the “heat island”

zones. Thus, the surface observations, on which global warming theories are built,

is contaminated by the urban heat island effect.

7.7.2 Impact of Changes in Topography

Topography plays the major role on Indian rainfall. For example, Western

Ghats helps in producing wet areas on windward direction (western parts of Ghats)

and dry areas on leeward direction (eastern parts of Ghats) during the Southwest


Monsoon season. The opposite pattern is produced during the Northeast Monsoon

season and as well due to cyclonic activity in Bay of Bengal. The box effect of

northeastern zone provides the zone of the highest rainfall in the world. Thus, the

destruction of topography changes the weather around that zone. Very few

studies attempted to quantify these changes.

Colaba and Santacruz within Mumbai show an increasing trend in rainfall

during 1961-1990 with Santacruz rainfall higher than Colaba rainfall by around

300 mm but at Santacruz the increasing trend in rainfall was countered due to

cutting of hillocks in the windward direction of Southwest Monsoon on the eastern

and northeastern side of Santacruz meteorological observatory on the runway

(Figure 7j). The mean annual rainfall at Colaba (1969, mm) and Santacruz (2288,

mm) shows a difference of 318.8 mm. The same during a wet year it is –127 mm

and a dry year it is 396 mm. That is, the change in topography in the windward

area reduced the rainfall by around 150 mm.


7.7.3 Cold Island Effect

To meet the food and other needs of the unabated growth in population, in

agriculture large-scale changes in land-use have taken place and this is a continuous

process. In this process there are important changes are noticed, namely changes in

crops & cropping pattern & the duration; and spread of reservoirs – rural ecological

changes. These changes create changed weather system. Figure 7k presents the

trend in 28-year period averages in the three meteorological sub-divisions in Andhra

Pradesh in the two rainy seasons, namely the Southwest Monsoon (SWM) – left

side and the Northeast Monsoon (NEM) – right side. The numbers on the curves

present the % number of years the rainfall less than the average rainfall during the

respective monsoon seasons (SWM/NEM) in each of the three meteorological sub-

divisions of Andhra Pradesh. It is clear from the figure that the trend is significant

and early in Coastal Andhra sub-division in which the changes in agriculture took

place earlier with the two dams, one on Krishna at Vijayawada and the other on

Godavari at Rajahmundry. Rayalaseema sub-division presents a weak-trend as the

land use change is limited to smaller areas only. Table 9 presents the temporal

variation in the area under irrigation in the three meteorological sub-divisions of AP.

However, in Andhra Pradesh, the state government initiated cloud seeding

operations since 2004 along with several other changes in land use and changes in

land cover, which may change the rainfall over different parts of the state in near

future. The state receives rainfall predominantly in association with cyclonic systems.

The cloud seeding operators are seeding invariably such cyclonic systems that

severely affect the rainfall in downwind direction. At present it is not easy to

separate this from the trend in rainfall but the preliminary analysis of the result

clearly indicate a decrease in rainfall in down wind direction (Reddy, 2004).

Table 9: Temporal variation of the irrigated area

in the three sub-divisions of AP

Region Area under irrigation

(lakh hectares)

1955-56 1999-00

Coastal Andhra 17.23 22.01

Telangana 6.43 15.71

Rayalaseema 3.81 6.12

AP 27.47 43.84

7.7.4 Deforestation Effect

Tropical Deforestation Affects US Climate (Mike Bettwy, Goddard Space Flight

Center release September 20, 2005) results are summarized as: Today, scientists

estimate that between one-third and one-half of our planet’s land surfaces have

been transformed by human development. Now, a new study is offering insight

into the long-term impacts of these changes, particularly the effects of large-scale

deforestation in tropical regions on the global climate. Researchers from Duke


University, Durham, N.C., analyzed multiple years of data using the NASA Goddard

Institute for Space Studies General Circulation Computer Model (GCM) and Global

Precipitation Climatology Project (GPCP) to produce several climate simulations.

Their research found that deforestation in different areas of the globe affects

rainfall patterns over a considerable region.

Deforestation would result in a reduction in precipitation and increase in

temperature in the Amazon basin — This pattern was also revealed in studies

carried out in early 1970s by India Meteorological Department on the impact of

deforestation on Simla rainfall. “Our study carried somewhat surprising results,

showing that although the major impact of deforestation on precipitation is found

in and near the deforested regions, it also has a strong influence on rainfall in the

mid and even high latitudes,” said Roni Avissar, lead author of the study, published

in the April 2005 issue of the Journal of Hydrometeorology. Specifically,

deforestation of Amazonia was found to severely reduce rainfall in the Gulf of

Mexico, Texas, and northern Mexico during the spring and summer seasons when

water is crucial for agricultural productivity. Deforestation of Central Africa has a

similar effect, causing a significant precipitation decrease in the lower U.S Midwest

during the spring and summer and in the upper U.S. Midwest in winter and spring.

Deforestation in Southeast Asia alters rainfall in China and the Balkan Peninsula

most significantly. Elimination of any of these tropical forests, Amazonia, Central

Africa or Southeast Asia, considerably enhances rainfall in the southern tip of the

Arabian Peninsula. However, the combined effect of deforestation in all three

regions shifts the greatest precipitation decline in the U.S. to California during

the winter season and further increases rainfall in the southern tip of the Arabian

Peninsula.

Improved understanding of tropical forested regions is valuable to scientists

because of their strong influence on the global climate. The tropics receive two-

thirds of the world’s rainfall, and when it rains, water changes from liquid to vapor

and back again, storing and releasing heat energy in the process. With so much

rainfall, an incredible amount of heat is released into the atmosphere - making the

tropics the Earth’s primary source of heat redistribution. Avissar says, “Deforestation

does not appear to modify the global average of precipitation, but it changes

precipitation patterns and distributions by affecting the amount of both sensible

heat and that released into the atmosphere when water vapor condenses, called

latent heat. Associated changes in air pressure distribution shift the typical global

circulation patterns, sending storm systems off their typical paths”.

The accelerating destruction of the rainforests that form a precious cooling band

around the Earth’s equator, is now being recognized as one of the main causes of

climate change. Carbon emissions from deforestation far outstrip damage caused

by planes and automobiles and factories. The rampant slashing and burning of

tropical forests is second only to the energy sector as a source of greenhouse

gases according to report published by the Oxford-based Global Canopy Programme,

an alliance of leading rainforest scientists. “Tropical forests are the elephant in the

living room of climate change,” said Andrew Mitchell, the head of the GCP. Scientists


say one days’ deforestation is equivalent to the carbon footprint of eight million

people flying to New York. Reducing those catastrophic emissions can be achieved

most quickly and most cheaply by halting the destruction in Brazil, Indonesia, the

Congo and elsewhere.

The rainforests of the Amazon, the Congo basin and Indonesia are thought

of as the lungs of the planet. But the destruction of those forests will in the next

four years alone, in the words of Sir Nicholas Stern, pump more CO2 into the

atmosphere than every flight in the history of aviation to at least 2025. Indonesia

became the third-largest emitter of greenhouse gases in the world last week.

Following close behind is Brazil. Neither nations have heavy industry on a comparable

scale with the EU, India or Russia nor yet they comfortably outstrip all other

countries, except the United States and China.

Standing forest was not included in the original Kyoto protocols and stands

outside the carbon markets that the report from the IPCC pointed to this month as

the best hope for halting catastrophic warming. The landmark Stern Report last

year, and the influential McKinsey Report in January agreed that forests offer the

“single largest opportunity for cost-effective and immediate reductions of carbon

emissions”.

The standing forests generate the bulk of rainfall worldwide and act as a

thermostat for the Earth. Forests are also home to 1.6 billion of the world’s poorest

people who rely on them for subsistence. However, forest experts say governments

continue to pursue science fiction solutions to the coming climate catastrophe,

preferring bio-fuel subsidies, carbon capture schemes and next-generation power

stations. Putting a price on the carbon these vital forests contain is the only way

to slow their destruction. Hylton Philipson, a trustee of Rainforest Concern,

explained: “In a world where we are witnessing a mounting clash between food

security, energy security and environmental security - while there’s money to be

made from food and energy and no income to be derived from the standing forest,

it’s obvious that the forest will take the hit.”

Slash-and-burn agriculture elsewhere (in particular in Indonesia, Southeast

Asia and tropical Africa in dry years) may also have a profound effect on climate

(McGuffie, K. and A. Henderson-Sellers in 1997). It can be argued that because

the smoke CCN are short-lived, and because the CO2 emissions involved are relatively

small, the direct effect of the burning on climate is mostly transient and therefore

deforestation is of little importance to climate. However the long-term change in

land surface conditions may have a lasting effect on climate through changes in

surface heat fluxes, rainfall, and greenhouse gas production (e.g. methane).

All these, clearly reflects that ecological changes have both direct and indirect

effects on weather in addition to direct impact on environment & life forms on the

Earth. Unfortunately, the researchers’ haven’t given that much importance as that

given to hypothetical global warming theories as these needs only sophisticated

computers without scientifically validated data sets. There is an urgent need to

change the mind set in this direction to solve the climate change problem as a


long-term solution.

From the above discussions it is also clear that ecological changes not only

influence the radiation balance in the atmosphere but also the greenhouse gases,

principally CO2 balance in the atmosphere. This creates a permanent change in the

greenhouse gases balance in the atmosphere. The principal contributors of

anthropogenic greenhouse gases are fossil fuels such as coal, oil & gas. It was

estimated in 2005 that the total world-wise energy consumption was 138,900

Twh with around 85%± 10% (oil 37%, coal 25% & gas 23%) of primary energy

production in the world come from burning fossil fuels are non-renewable. World

recoverable coal reserve is estimated as 4,416,000 million barrels equivalent. At

the present rate (29 million barrels equivalent per day) of use, it will lost up to 417

years. Oil reserves are 1,317,000 million barrels will lost (84 million barrels per day)

for 43 years and gas 1,161,000 million barrels equivalent lost (19 million barrels

equivalent per day) for 167 years.

It is proposed to use renewable energy sources that are naturally replenishble,

such as sunlight, wind, rain, tides and geothermal heat in place of fossil fuels to

reduce the greenhouse gases emissions into the atmosphere. Renewable technologies

include solar power, wind power, hydroelectric power, biomass, etc. In 2006, about

18% of global final energy consumption come from renewables, with 13% coming

from traditional biomass such as wood burning. Hydropower was the next largest

with 3%. We need spectacular breakthroughs in technologies to stop or reduce

the use of fossil fuels in energy production. However, in light of the ecological

changes changing the greenhouse gases balance in the atmosphere, there is a

need to re-look into the greenhouse gases vs global warming theories proposed

based on numerical models.


Chapter 8

Global Warming

8.1 What is Global Warming (GW)?

Global warming is the increase in the average temperature of the Earth’s

near-surface air and Oceans since the mid-twentieth century, and its projected

continuation. The average global air temperature near the Earth’s surface increased

by 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the hundred years ending in 2005.

The basic question is whether the observed increase in globally averaged

temperatures since the mid-twentieth century is due to the observed increase in

anthropogenic (man-made) greenhouse gases (GHGs) concentrations via the

greenhouse effect or due to a combination of natural and man made effects like

urban contamination. A report says, “There is a related question of whether warming

is due to human activities or the end of a little ice age. The main external climate

forcings experienced over the last 2,000 years are volcanic eruptions, changes in

solar radiation reaching the Earth, and increases in atmospheric greenhouse gases

and aerosols due to human activities. Proxy records are available for reconstructing

climate forcings over the last 2,000 years, but these climate forcings reconstructions

are associated with as much uncertainty as surface temperature reconstructions”.

The report also says, “Greenhouse gases and tropospheric aerosols varied

little from A.D. 1 to around 1850. Volcanic eruptions and solar fluctuations were

likely the most strongly varying external forcings during this period, but it is currently

estimated that the temperature variations caused by these forcings were much

less pronounced than the warming due to greenhouse gas forcing since the mid

19th century. Climate model simulations indicate that solar and volcanic forcings

together could have produced periods of relative warmth and cold during the pre-

industrial portion of the last 1,000 years. However, anthropogenic greenhouse gas

increases are needed to simulate late 20th century warmth”.

Report from the National Academy of Sciences - National Research Council

(NAS/NRC) entitled CLIMATE CHANGE SCIENCE, AN ANALYSIS OF SOME KEY

QUESTIONS marks the first time a study commissioned by the federal government

has publicly concluded that global warming exists. The study says that global

warming “is real and particularly strong within the past 20 years”. A total of 14

specific questions were addressed by the study, ranging from “Is climate change

occurring? If so, how?” to “What are the specific areas of science that need to be

studied further, in order of priority, to advance our understanding of climate

change?” The report further states “greenhouse gases are accumulating in Earth’s

atmosphere as a result of human activities, causing surface air temperatures and

subsurface ocean temperatures to rise. Temperatures are, in fact, rising”. The

report notes that “changes observed over the last several decades are likely mostly

due to human activities,” but the NAS/NRC says, could not rule out the possibility

that a significant part of the climate changes could be the result of natural variability.


Regardless of the reason for the climate change, global warming is expected to

continue through the 21st century. While in some areas, the rising temperatures

will cause a rise in sea level. Computer model simulations also project “an increased

tendency towards drought over semi-arid regions, such as the U.S. Great Plains”.

The NAS/NRC also looked for substantive differences between the

Intergovernmental Panel on Climate Change (IPCC) Report and its published

summary. According to the NAS/NRC, the IPCC summary “largely represents the

consensus scientific views and judgments of the committee members, based on

the accumulated knowledge that these individuals have gained – both through

their own scholarly efforts and through formal and informal interactions with the

world’s climate change science community.” One of the specific questions asked

of the NAS/NRC was “By how much will temperatures change over the next 100

years and where?” The highest estimate of the atmospheric temperature increase

is 10.4oF. While this may not seem to be a particularly large change when looking

on the short term, the long-term impact of such a change is significant.

According to their report, “Higher evaporation rates would accelerate the

drying of soils following rain events, resulting in lower relative humidities and

higher daytime temperatures, especially during the warm season”. There is evidence

to suggest that droughts as severe as the “dust bowl” of the 1930’s were much

more common during the 10th and 14th centuries than they have been in recent

record. Another major question the study addressed was, “What will be the

consequences (e.g., extreme weather, health effects) of increases [in temperature]

of various magnitude?” The study concludes “Hydrologic impacts could be

significant over the western United States, where much of the water supply is

dependent on the amount of snow pack and the timing of the spring runoff.” This

is a small example, how global warming theory is running on “ifs and buts” that

needs clear-cut solutions!!!

National Research Council of USA in its’ 2006 report presented smoothed

reconstructions of large scale (Northern Hemisphere and global mean) surface

temperature using different paleoclimatological proxy data sets. The data sets

present large differences among different reconstructed temperature pattern with

time. The basic question is how realistic is to compare present trend with past

obtained from such proxy data series?

8.2 Global Climate Models

With the advent of modern fast and sophisticate computers, use of models

in solving problems has increased multifold in all areas of science. However, models

have significant limitations basically because they carryout as per the creation by

the human brain that may not take into account all physical process involved in

the nature. But, computers can handle huge quantity of data that human brain

can’t handle. Thus people started meddling with models and they became a special

class in scientific community. Thus models become “Survival Research” tools


without proper understanding of physical process in right perspective, this is more

so in climate & weather studies and thereby ground based studies took back-seat.

Let me present an example from my experience in late 70’s of a crop growth model

(SORGF model), developed under extra-tropical conditions and tried to implement

the same in tropical conditions. Temperature is the limiting factor in ex-tropical

conditions and moisture is the limiting factor under tropical conditions for the

crop production. Because of this, the model failed in the tropical conditions. The

model gave root mean square errors and correlation coefficients for dry matter and

grain yields respectively: 27.58 and 17.39 q/ha, and 0.35 and 0.37. By changing

the moisture parameters, estimated using a model (Reddy, 1983c) developed under

tropical conditions, gave 15.06 and 8.49 q/ha, and 0.85 and 0.81, respectively

(Reddy, 1983-84). However, the authors of the SORGF model refused to change

the model structure. Thus, with the changed management came another model

developed in the extra-tropical conditions by another group of scientists; and

again this is also replaced. The process continued to meet the survival research

needs. The same tendency is seen in the study of McKenny & Rosenberg (1993)

“Sensitivity of some potential evapotranspiration estimation methods to climate

change”. The fact is that the authors tried to estimate potential evapotranspiration

using highly erroneous models. Thus, the study of senstivity of such estimates has

no meaning.

Computer models of the Earth’s climate system are known as general

circulation models (GCMs). The validity of such models depends upon soundness

in their physical basis, and their skill in representing observed climate and past

climate changes. Though, the models are based on physical principles of fluid

dynamics, radiative transfer, and other processes, started using with simplifications,

as the climate system is complex. All modern climate models include an atmospheric

model that is coupled to the Ocean model and models for ice cover on land and

sea. Some models also include treatments of chemical and biological processes.

These models predict that the effect of adding GHGs is to produce a warmer

climate. However, even when the same assumptions of future GHG levels are used,

there still remains a considerable range of climate sensitivity, as it is not clear how

and in what way the GHGs increase temperature.

Prior to 2001 the estimates of global warming were made from a range of

climate models under the IPCC Special Report on Emissions [SRES] A2 emissions

scenario, which assumes no action is taken to reduce emissions. Figure 8a presents

an example of global warming projections by different models. They present

temperatures at the end of 2100 varying between 2 and 5 °C. The geographic

distribution of surface warming during the 21st century calculated by the HadCM3

climate model if a business as usual scenario is assumed for economic growth and

GHG emissions. In this the globally averaged warming corresponds to 3.0 °C (5.4 °F).

Including uncertainties in future GHG concentrations and climate modeling, the

IPCC anticipates a warming of 1.1 °C to 6.4 °C by the end of the 21st century,

relative to 1980–1999.


8.3 Factors Contributing GW

8.3.1 The Natural Heating & Cooling

Greenhouse gases and greenhouse effect: The greenhouse effect was discovered

by Joseph Fourier in 1824 and was first investigated quantitatively by Svante

Arrhenius in 1896. It is the process by which absorption and emission of infrared

radiation by atmospheric gases warm a planet’s lower atmosphere and surface.

Existence of the greenhouse effect as such is not disputed. Naturally occurring

GHGs have a mean warming effect, without which the Earth would be

uninhabitable. On the Earth, the major GHGs are water vapour, which causes

about 36–70% of the greenhouse effect (not including clouds); carbon dioxide

(CO2), which causes 9–26%; methane (CH4), which causes 4–9%; and ozone,

which causes 3–7%. The issue is how the strength of the greenhouse effect

changes when human activity increases the atmospheric concentrations of some

GHGs?

It is reported that “Human activity since the industrial revolution has increased

the concentration of various GHGs, such as CO2, methane, tropospheric ozone,

CFCs and nitrous oxide. It is stated that molecule for molecule, methane is a more

effective GHG than carbon dioxide, but its concentration is much smaller so that

its total radiation exchange capacity is only about a fourth of that from carbon


dioxide. Some other naturally occurring gases contribute very small fractions of

the greenhouse effect; one of these, nitrous oxide (N2O), is increasing in

concentration owing to human activity such as agriculture. It is also stated that

the atmospheric concentrations of CO2 and CH4 have increased by 31% and 149%

respectively since the beginning of the industrial revolution in the mid-1700s –

though in percentage-wise it looks high with methane over carbon dioxide but in

terms of volume it is the carbon dioxide higher than methane. These percentages

are relative to non-instrumental observations. From less direct geological evidence

it is believed that CO2 values this high were last attained 20 million years ago.

Fossil fuel burning has produced approximately three-quarters of the increase in

CO2 from human activity over the past 20 years. Most of the rest is due to land

use change, in particular deforestation”. The exactness of this is in question!!!

World Meteorological Organization (WMO) compiled data relating to carbon dioxide

and stations recording it. The fact remains that the GHG concentrations for the

past are built on indirect methods of estimation. Figure 8b [Source: Siegen Thaler

& Oeschger, Tellus, 39B: 140-154, 1987] presents the atmospheric carbon dioxide

increase in the past 200 years as indicated by measurements on air trapped in old

ice from Siple station, Antarctica, by infrared laser spectroscopy (full triangles) &

by gas chromatography (open squares) and the annual mean values from Mauna

Loa Observatory (crosses). That means, only in the last five decades it is measured


and that too at few selected locations (Figure 8c), which are unevenly distributed

over different parts of the globe [Source: WMO Fact Sheet No. 4, August 1989].

Figure 8d presents (Robinson et

al., 1988 – Review in Geophysics,

1988) monthly mean CO2

concentrations at the NOAA-

Geophysical Monitoring for

Climate Change Laboratory at

South Pole and Barrow, Alaska

Observatories, 1973-1987. The

monthly CO2 measurements

display seasonal oscillations in

an overall yearly up trend; each

year’s maximum is reached

during the Northern

Hemisphere’s late spring, and

declines during the Northern

Hemisphere growing

season as plants

remove some CO2

from the

a t m o s p h e r e .

Under the changed CO2 sinks scenarios, the balance must change!!!

Reports say, “Recent data indicate that carbon dioxide is accumulating in

the atmosphere at a greater

rate than in the past. In 2005

the concentration of carbon

dioxide in the atmosphere

increased by 2.5 parts per

million (ppm), the third

largest annual increase ever

recorded. Although there is

considerable inter-annual

variability in the rate of

increase in atmospheric

carbon dioxide, the rise has

been more than 2 ppm in 3

of the last 4 years. Prior to

1995, an annual increase of

more than 2 ppm was seen

only 4 times since the record

began in

1959. As a

result of


recent jumps, the current atmospheric concentration of carbon dioxide is now

over 380 ppm. This is an increase of more than 100 ppm since the start of the

Industrial Revolution, and ice core records show that it is the highest concentration

of atmospheric carbon dioxide for at least the last 650,000 years”.

Figure 8e presents the total fossil fuel consumption, which is identified as

the main source of the observed CO2 increase, in Southern and Northern

Hemispheres. The projections for the year 2000 compared with those of 1960

indicate that consumption will have more than quadruples in the Southern

Hemisphere while that in the Northern Hemisphere will have more than doubled in

relative terms but in magnitude the Northern Hemisphere consumed more over the

Southern Hemisphere. From the WMO Fact Sheet No. 4 (August 1989), it is clear

that very few stations are measuring changing composition [Figure 8c] of the

atmosphere, including the increases of GHGs (CO2, CH4, N2O, tropospheric O3,

CFCs) especially in tropics (by that time no data) and the Southern Hemisphere

(by that time only three sites]. With such a data sets, presenting un-believably

smooth curve, scientists are filling the literature with highly hypothetical inferences.

Tropospheric Ozone: Tropospheric ozone (see Chapter 2) is created by chemical

reactions from automobile, power plant and other industrial and commercial source

emissions in the presence of sunlight. It is estimated that O3 has increased by

about 36% since the pre-industrial era, although substantial variations exist for

regions and overall trends (IPCC, 2007). Besides being a GHG, ozone can also be a

harmful air pollutants at ground level, especially for people with respiratory diseases

and children and adults who are active outdoors.

Chlorofluorocarbons (CFCs) & Hydrochlorofluorocarbons (HCFCs): CFCs & HCFCs

are used in coolants, foaming agents, fire extinguishers, solvents, pesticides and

aerosol propellants. These compounds have steadily increased in the atmosphere

since their introduction in 1928. Concentrations are slowly declining as a result of

their phase out via the Montreal Protocol on Substances that deplete the ozone

layer [see Chapter 2). Fluorinated gases such as Hydrofluorocarbons (HFCs),

Perfluorocarbons (PFCs), and Sulfur hexafluoride (SF6) are frequently used as

substitutes for CFCs and HCFCs and are increasing in the atmosphere. It is noted

that these various fluorinated gases are sometimes called “high global warming

potential greenhouse gases” because, molecule for molecule, they trap more heat

than CO2 .

Aerosols: The burning of fossil fuels and biomass (living matter such as vegetation)

has resulted in aerosol emissions into the atmosphere. Aerosols absorb and emit

heat, reflect light and, depending on their properties, can either cool or warm the

atmosphere. Sulfate aerosols are emitted when fuel-containing sulfur, such as

coal and oil, is burned. Sulfate aerosols reflect solar radiation back to space and

have a cooling effect. These aerosols have decreased in concentration in the past

two decades resulting from efforts to reduce the coal fired power plant emissions

of sulfur dioxide in the United States and other countries. Black carbon (or soot)

results from the incomplete combustion of fossil fuels and biomass burning (forest


fires and land clearing) and is believed to contribute to global warming (IPCC,

2007). Though global concentrations are likely increasing, there are significant

regional differences. Other aerosols emitted in small quantities from human activities

include organic carbon and associated aerosols from biomass burning. Mineral

dust aerosols (e.g., from deserts and lake beds) largely originate from natural

sources, but their distribution can be affected by human activities.

Fossil Fuels & Land use changes: The present atmospheric concentration of CO2

is about 385 parts per million (ppm) by volume. Future CO2 levels are expected to

rise due to ongoing burning of fossil fuels and land-use change. The rate of rise

will depend on uncertain economic, sociological, technological, and natural

developments & technological inventions but may be ultimately limited by the

availability of fossil fuels. The IPCC Special Report on Emissions Scenarios gives a

wide range of future CO2 scenarios, ranging from 541 to 970 ppm by the year

2100 – this range indicates, no body knows the reasonable level of carbon dioxide

by 2100. Fossil fuel reserves are sufficient to reach this level and continue emissions

past 2100. Research by NASA climate scientist James Hansen indicates mainly

GHGs other than carbon dioxide have driven the 0.75 °C rise in average global

temperatures over the last 100 years. Though he is the first few to claim linking

CO2 to global warming in 1981. With this the politics of global warming has

taken a new twist, conflict between developing and developed countries.

CO2 Produces CO2: It is reported that the heating or cooling of the Earth’s surface

can cause changes in GHG concentrations. That is, when global temperatures

become warmer, CO2 is released from the Oceans. When changes in the Earth’s

orbit trigger a warm (or interglacial) period, increasing concentrations of CO2 may

amplify the warming by enhancing the greenhouse effect. When temperatures

become cooler, CO2 enters the Ocean and contributes to additional cooling. During

at least the last 650,000 years, CO2 levels have tended to track the glacial cycles

(IPCC, 2007). That is, during warm interglacial periods, CO2 levels have been high

and during cool glacial periods, CO2 levels have been low. This means, the high

year-to-year variations in temperature must contribute significant changes in CO2

levels, which is not seen in Figure 8b, though there are significant seasonal changes

(Figure 8d). The curve in Figure 8b presents a smooth curve without much variation.

However, one thing is clear from the above discussions that during glacial and

interglacial periods, the changes in temperatures of the Ocean changed the CO2

levels and not vice-versa.

8.3.2 Radiative Forcing

Radiation forcing (RF) is the change in the balance between solar radiation

entering the atmosphere and the Earth’s radiation going out. On an average, a

positive RF tends to warm the surface of the Earth while negative RF tends to cool

the surface. It is reported that GHGs have a positive RF because they absorb and

emit heat. Aerosols can have a positive or negative RF, depending on how they

absorb and emit heat and/or reflect light. For example, black carbon aerosols -

which have a positive factor - more effectively absorb and emit heat than sulfates,

which have a negative factor and more effectively reflect light.


IPCC (2007) presented estimates of the change in RF in the year 2005

relative to 1750 for different components of the climate: “It is reported that the

RF contribution (since 1750) from increasing concentrations of well-mixed GHGs

(including CO2 , CH4, N2

O, CFCs, HCFCs, and fluorinated gases) is estimated to

be +2.64 Watts per square meter - over half due to increases in CO2 (+1.66

Watts per square meter), strongly contributing to warming relative to other climate

components; The RF contribution from increasing tropospheric ozone, an unevenly

distributed GHG, is estimated to be +0.35 Watts per square meter (on average),

resulting in a relatively small warming effect. This factor varies from region to

region depending on the amount of ozone in the troposphere at a particular location.

The RF contribution from the observed depletion of stratospheric ozone is estimated

to be -0.05 Watts per square meter, resulting in a relatively small cooling effect.

While aerosols can have either positive or negative contributions to RF, the net

effect of all aerosols added to the atmosphere has likely been negative. The best

estimate of aerosols’ direct cooling effect is -0.5 Watts per square meter; the best

estimate for their indirect cooling effect (by increasing the reflectivity of clouds)

is -0.7 Watts per square meter, with an uncertainty range of -1.8 to -0.3 Watts per

square meter. Therefore, the net effect of changes in aerosol RF has likely resulted

in a small to relatively large cooling effect”. For well-mixed GHGs, mathematical

equations are used to compute RF based on changes in their concentration relative

to 1750 (or 1990 for NOAA’s AGGI) and the known radiative properties of the

gases. IPCC claim “high confidence in these calculations due to reliable current

and historic concentration data and well-established physics”. The uncertainty

factor clearly demonstrates that these estimates are highly unreliable.

Due to limited measurements and regional variation, changes in tropospheric

ozone, aerosols, land use (see Chapter 7) and the Sun’s intensity are much more

uncertain. In the case of aerosols, uncertainty is increased due to an incomplete

understanding of how aerosols interact with clouds and the effects the interactions

have on aerosol RF. That means, the whole theory behind RF effects of different

components are of hypothetical in nature and there is nothing to prove their

accuracy, though in GHGs they claim high confidence. The calculated data

presented above of combined effect of GHGs and aerosols appear to be negligible;

may be a little “heating or cooling”.

8.3.3 Feedback Factors

Evaporation: Various feedback processes complicate the effects of individual factors

on the climate. One of the most pronounced feedback effects relates to the

evaporation of water. It is stated that the warming by addition of long-lived GHGs

such as CO2 will cause more water to evaporate into the atmosphere. Since water

vapor itself acts as a GHG, the atmosphere warms further; this warming causes

more water vapor to evaporate (a positive feedback), and so on until other processes

stop the feedback loop. The result is a much larger greenhouse effect than that

due to CO2

alone. Although this feedback process causes an increase in the

absolute moisture content of the air, the relative humidity stays nearly constant or


even decreases slightly because the air is warmer. It is argued that “this feedback

effect can only be reversed slowly as CO2 has a long average atmospheric lifetime”.

Clouds: Clouds emit infrared radiation back to the surface, and so exert a warming

effect; seen from above, clouds reflect sunlight and emit infrared radiation to

space, and so exert a cooling effect. Whether the net effect is warming or cooling

depends on details such as the type and altitude of the cloud. It is argued that

“these details are difficult to represent in climate models, in part because clouds

are much smaller than the spacing between points on the computational grids of

climate models. Nevertheless, cloud feedback is second only to water vapor feedback”

and is positive in all the models that were used in the IPCC Fourth Assessment

Report. This is more seasonal and regional contrary to water vapour. But both vary

with the years. However, it is an important factor in the net radiation intensity at

local-regional- national levels.

Lapse Rate: A subtler feedback process relates to changes in the lapse rate as the

atmosphere warms. The atmosphere’s temperature decreases with the height in

the troposphere. Since emission of infrared radiation varies with the fourth power

of temperature, long-wave radiation emitted from the upper atmosphere is less

than that emitted from the lower atmosphere. Most of the radiation emitted from

the upper atmosphere escapes to space, while most of the radiation emitted from

the lower atmosphere is re-absorbed by the surface or the atmosphere. Thus, the

strength of the greenhouse effect depends on the atmosphere’s rate of temperature

decrease with height: if the rate of temperature decrease is greater the greenhouse

effect will be stronger, and if the rate of temperature decrease is smaller then the

greenhouse effect will be weaker. Both theory and climate models indicate that

warming will reduce the decrease of temperature with height, producing a negative

lapse rate feedback [inversion effect] that weakens the greenhouse effect. The

rate of temperature change with height is very sensitive to small errors in

observations, making it difficult to establish whether the models agree with

observations. The lapse rates are influenced by localized factors as well on solar

factors.

Albedo: Another important feedback process is ice-albedo feedback. When global

temperatures increase, ice near the poles melts at an increasing rate. As the ice

melts, land or open water takes its place. Both land and open water are on average

less reflective than ice, and thus absorb more solar radiation. This causes more

warming, which in turn causes more melting, and this cycle continue. The ecological

changes such as land use – land cover change (see Chapter 7) plays major role on

this.

Thermal inversions: This plays an important role in winter period, particularly in

high latitude belt under pollution.

Changes in the Ocean Currents: It is a fact that the heating or cooling of the

Earth’s surface can cause changes in the Ocean currents. As the Ocean currents

play a significant role in distributing heat around the Earth, changes in these

currents can bring about significant changes in climate from region to region. The


long-term systematic variations in temperature, such as glacial and interglacial

periods, play an important role on this.Positive feedback due to release of CO2

and CH4 from thawing permafrost, such as the frozen peat bogs in Siberian, is an

additional mechanism that could contribute to warming. Similarly a massive release

of CH4 from methane clathrates in the Ocean could cause rapid warming, according

to the clathrate gun hypothesis. The Ocean’s ability to sequester carbon is expected

to decline as it warms. This is because the resulting low nutrient levels of the

mesopelagic zone (about 200 to 1000 m depth) limit the growth of diatoms in

favor of smaller phytoplankton that are poorer biological pumps of carbon.

8.3.4 Other Factors

Solar Variations: Changes occurring within (or inside) the Sun can affect the

intensity of the sunlight that reaches the Earth’s surface. The intensity of the

sunlight can cause either warming (for stronger solar intensity) or cooling (for

weaker solar intensity). According to NASA Research, reduced solar activity from

the 1400s to the 1700s was likely a key factor in the “Little Ice Age” which

resulted in a slight cooling of North America, Europe and probably other areas

around the globe. Some studies related to solar variations are summarized in

Chapter 6. The impact of solar related factors on weather were significantly

reported in a number of research papers published prior to 1980.

A paper by Peter Stott and other researchers suggests that climate models

overestimate the relative effect of GHGs compared to solar factor; they also suggest

that the cooling effects of volcanic dust and sulfate aerosols have been

underestimated. A different hypothesis is that variations in solar output, possibly

amplified by cloud seeding via galactic cosmic rays, may have contributed to

recent warming. It suggests magnetic activity of the Sun is a crucial factor, which

deflects cosmic rays that may influence the generation of cloud condensation

nuclei and thereby affect the climate. One predicted effect of an increase in solar

activity would be a warming of most of the stratosphere, whereas GHG theory

predicts cooling there. The observed trend since at least 1960 has been a cooling

of the lower stratosphere. Reduction of stratospheric ozone also has a cooling

influence, but substantial ozone depletion did not occur until the late 1970s. Solar

variation combined with changes in volcanic activity probably did have a warming

effect from pre-industrial times to 1950, but a cooling effect since.

In 2006, Peter Foukal and other researchers from the United States, Germany,

and Switzerland found no net increase of solar brightness over the last thousand

years. Solar cycles led to a small increase of 0.07% in brightness over the last

thirty years. This effect is far too small to contribute significantly to global warming.

A paper by Mike Lockwood and Claus Fröhlich found no relation between global

warming and solar radiation since 1985, whether through variations in solar output

or variations in cosmic rays. Henrik Svensmark and Eigil Friis-Christensen, the main

proponents of cloud seeding by galactic cosmic rays, disputed this criticism of

their hypothesis. A 2007 paper found that in the last 20 years there has been no

significant link between changes in cosmic rays coming to Earth and cloudiness


and temperature. Here, we must not forget that the effects associated solar variation

have not only direct effects but also indirect effects. By integrating these two

impacts that vary with the situation to situation only it is possible to determine

the quantitative impact of solar variations on weather. This is clearly demonstrated

in the case of solar flares impact on lower tropospheric weather.

Causes of Change Prior to the Industrial Era (pre-1780): Known factors of past

climate change include: Changes in the Earth’s orbit: changes in the shape of the

Earth’s orbit (or eccentricity) as well as the Earth’s tilt and precession affect the

amount of sunlight received on the Earth’s surface. These orbital processes —

which function in cycles of 100,000 (eccentricity), 41,000 (tilt), and 19,000 to

23,000 (precession) years — are thought to be the most significant drivers of ice

ages according to the theory of Mulitin Milankovich, a Serbian mathematician

(1879-1958). Studies of the Earth’s previous climate suggest periods of stability

as well as periods of rapid change. Long string of widespread, large and abrupt

climate changes were associated with glacial periods (NRC, 2002). It is also reported

that abrupt or rapid climate changes tend to frequently accompany transitions

between glacial and interglacial periods (and vice versa) and thus, abrupt climate

changes have occurred throughout the Earth’s history. It was noted that human

civilization arose during a period of relative climate stability. During the last 2,000

years, the climate has been relatively stable. The issue of whether the temperature

rise of the last 100 years crossed over the warm limit of the boundary defined by

the Medieval Climate Anomaly has been a controversial topic in the science

community. The National Academy of Sciences recently completed a study to

assess the efforts to reconstruct temperatures of the past one to two millennia

and place the Earth’s current warming in historical context (NRC, 2006).

Volcanic eruptions: Volcanoes can affect the climate because they can emit aerosols

and carbon dioxide into the atmosphere. Volcanic aerosols tend to block sunlight

and contribute to short term cooling. Aerosols do not produce long-term change

because they leave the atmosphere not long after they are emitted. According to

the US Geological Survey (USGS), the eruption of the Tambora Volcano in Indonesia

in 1815 lowered global temperatures by as much as 5ºF and historical accounts in

New England describe 1816 as “the year without a summer.” Volcanoes also emit

carbon dioxide (CO2 ). For about two-thirds of the last 400 million years, geologic

evidence suggests CO2 levels and temperatures were considerably higher than

present. One theory is that volcanic eruptions from rapid sea floor spreading elevated

CO2 concentrations, enhancing the greenhouse effect and raising temperatures.

However, the evidence for this theory is not conclusive and there are alternative

explanations for historic CO2 levels (NRC, 2005). While volcanoes may have raised

pre-historic CO2 levels and temperatures, according to the USGS Volcano Hazards

Program, human activities now emit 130 times as much CO2 as volcanoes (whose

emissions are relatively modest compared to some earlier times). These climate

change factors often trigger additional changes or “feedbacks” within the climate

system that can amplify or dampen the climate’s initial response to them (whether

the response is warming or cooling). How? Is there any evidence on such? These


are valid only when issues are dealt with practical data rather than theoretical/

hypothetical presumptions.

Tropospheric Temperature Change: Measurements of the Earth’s temperature

taken by weather balloons (also known as radiosondes) and satellites from the

surface to 5-8 miles into the atmosphere also reveal warming trends. According to

NOAA’s National Climate Data Centre: For the period 1958-2006, temperatures

measured by weather balloons warmed at a rate of 0.22°F per decade near the

surface and 0.27°F per decade in the mid-troposphere. The 2006 global mid-

troposphere temperatures were 1.01°F above the 1971-2000 average, the third

warmest on record. For the period beginning in 1979, when satellite measurements

of troposphere temperatures began, various satellite data sets for the mid-troposphere

showed similar rates of warming — ranging from 0.09°F per decade to 0.34°F per

decade, depending on the method of analysis (?). This range itself put doubts on

the warming of troposphere.

Stratospheric Temperature Change: Weather balloons and satellites have also

taken temperature readings in the stratosphere. This level of the atmosphere has

cooled. The cooling is consistent with observed stratospheric ozone depletion

since ozone is a GHG and has a warming effect when present. It’s also likely that

increased GHG concentrations in the troposphere are contributing to cooling in

the stratosphere as predicted by radiative theory. It is an illogical interpretation.

The major cooling effect at Antarctica zone is primarily related to the circumpolar

vertex formation that obstructs the mixing of warm middle latitude air with cool

polar air. That is system effect. This is clearly evident from the seasonal effects

and latitudinal effect on ozone depletion, observed over both Northern & Southern

Hemispheres (Chapter 2).

Recent Scientific Developments: The U.S. Climate Change Science Program

(CCSP) recently published a report, which addresses some of the long-standing

difficulties in understanding changes in atmospheric temperatures and the basic

causes of these changes. According to the report: There is no discrepancy in the

rate of global average temperature increase for the surface compared with higher

levels in the atmosphere. This discrepancy had previously been used to challenge

the validity of climate models used to detect and attribute the causes of observed

climate change. Errors identified in the satellite data and other temperature

observations have been corrected. These and other analyses have increased

confidence in the understanding of observed climate changes and their causes.

Research to detect global warming and attribute its causes using patterns of

observed temperature change shows clear evidence of human influences on the

climate system due to changes in GHGs, aerosols and stratospheric ozone. An

unresolved issue is related to the rates of warming in the tropics. Here, models and

theory predict greater warming higher in the atmosphere than at the surface.

However, greater warming higher in the atmosphere is not evident in three of the

five observational data sets used in the report. Whether this is a result of

uncertainties in the observed data, flaws in climate models, or a combination of


these is not yet known. The information presented above clearly demonstrate the

fact that a part of global warming is associated with human influence but this

does not mean, it is associated with GHGs. The realistic estimate of the contribution

of increasing GHGs on the warming is still a big question mark?

Ocean Acidification: A variety of issues are often raised in relation to global

warming. One is the Ocean acidification. Increased atmospheric CO2 increases the

amount of CO2 dissolved in the Oceans. CO2 dissolved in the Ocean reacts with

water to form carbonic acid, resulting in acidification. The Ocean surface pH is

estimated to have decreased from 8.25 near the beginning of the industrial era to

8.14 by 2004, and is projected to decrease by a further 0.14 to 0.5 units by 2100

as the Ocean absorbs more CO2. Since organisms and ecosystems are adapted to a

narrow range of pH, this raises extinction concerns, directly driven by increased

atmospheric CO2 , that could disrupt food webs and impact human societies that

depend on marine ecosystem services.

Global Dimming: The gradual reduction in the amount of global direct irradiance

at the Earth’s surface may have partially mitigated global warming in the late

twentieth century. From 1960 to 1990 human-caused aerosols likely precipitated

this effect. Scientists have stated with 66–90% confidence that the effects of

human-caused aerosols, along with volcanic activity, have offset some of the global

warming, and that GHGs would have resulted in more warming than observed if

not for these dimming agents. The Earth’s climate has changed throughout history.

From glacial periods (or “ice ages”) where ice covered significant portions of the

Earth to interglacial periods where ice retreated to the poles or melted entirely -

the climate has continuously changed. Scientists have been able to piece together

a picture of the Earth’s climate dating back decades to millions of years ago by

analyzing a number of surrogate, or “proxy,” measures of climate such as ice cores,

boreholes, tree rings, glacier lengths, pollen remains, and ocean sediments, and by

studying changes in the Earth’s orbit around the sun.

8.4 Mitigation of Global Warming

The IPCC’s Working Group III is responsible for crafting reports that deal with the

mitigation of global warming and analyzing the costs and benefits of different

approaches. In the 2007 IPCC Fourth Assessment Report, they conclude that no

one technology or sector can be completely responsible for mitigating future

warming. They find there are key practices and technologies in various sectors,

such as energy supply, transportation, industry, and agriculture that should be

implemented to reduce global emissions. They estimate that stabilization of carbon

dioxide equivalent between 445 and 710 ppm by 2030 will result in between a

0.6% increase and 3% decrease in global gross domestic product. According to

Working Group III, to limit temperature rise to 2 0C, “developed countries as a

group would need to reduce their emissions to below 1990 levels by 2020 (on the

order of –10% to 40% below 1990 levels for most of the considered regimes) and

to still lower levels by 2050 (40% to 95% below 1990 levels), even if developing

countries make substantial reductions.”


According to Hansen, et al. in 2007, paleoclimate data show that climate

sensitivity is ~3°C for doubled CO2 , including only fast feedback processes.

Equilibrium sensitivity, including slower surface albedo feedbacks, is ~6°C for

doubled CO2 for the range of climate states between glacial conditions and ice-

free Antarctica. Decreasing CO2 was the main cause of a cooling trend that began

50 million years ago, large scale glaciations occurring when CO2 fell to 450 ±

100 ppm, a level that will be exceeded within decades, barring prompt policy

changes. If humanity wishes to preserve a planet similar to that on which civilization

developed and to which life on the Earth is adapted, paleoclimate evidence and

ongoing climate change suggest that CO2 will need to be reduced from its current

385 ppm to at most 350 ppm. The basic weakness in this argument is, during the

glacial and interglacial periods, the changes in carbon dioxide was due to changes

in sea/ocean surface temperatures and vice-versa is not the case as stated above.

He further states that the largest uncertainty in the target arises from possible

changes of non-CO2 forcings. An initial 350-ppm CO

2 target may be achievable by

phasing out coal use except where CO2 is captured and adopting agricultural and

forestry practices that sequester carbon. If the present overshoot of this target

CO2 is not brief, there is a possibility of seeding irreversible catastrophic effects. A

probabilistic analysis concluded that the long-term CO2 limit is in the range 300-

500 ppm for 25 percent risk tolerance, depending on climate sensitivity and non-

CO2 forcings. Stabilizing atmospheric CO

2 and climate requires that net CO

2

emissions approach zero, because of the long lifetime of CO2 . We use paleoclimate

data to show that long-term climate has high sensitivity to climate forcings and

that the present global mean CO2 , 385 ppm, is already in the dangerous zone.

Despite rapid current CO2 growth, ~2 ppm/year, we show that it is conceivable

to reduce CO2 this century too less than the current amount, but only via prompt

policy changes. A global climate forcing, measured in W/m2 averaged over the

planet, is an imposed perturbation of the planet’s energy balance. Increase of

solar irradiance (So) by 2% and doubling of atmospheric CO2 are each forcings of

about 4 W/m2.

Charney defined an idealized climate sensitivity problem, asking how much

global surface temperature would increase if atmospheric CO2 were instantly

doubled, assuming that slowly changing planetary surface conditions, such as ice

sheets and forest cover, were fixed. Long-lived GHGs, except for the specified

CO2 change, were also fixed, not responding to climate change. The Charney

problem thus provides a measure of climate sensitivity including only the effect of

‘fast’ feedback processes, such as changes of water vapor, clouds and sea ice.

Classification of climate change mechanisms into fast and slow feedbacks is useful,

even though time scales of these changes may overlap. We include as fast feedbacks

aerosol changes, e.g., of desert dust and marine dime thylsulfide that occur in

response to climate change. Charney used climate models to estimate fast-feedback

doubled CO2 sensitivity of 3 ± 1.5°C. Water vapor increase and sea ice decrease

in response to global warming were both found to be strong positive feedbacks,


amplifying the surface temperature response. Climate models in the current IPCC

assessment appears to agree with Charney’s estimate.

Climate models alone are unable to define climate sensitivity more precisely,

because it is difficult to prove that models realistically incorporate all feedback

processes. The Earth’s history, however, allows empirical inference of both fast

feedback climate sensitivity and long-term sensitivity to specified GHG change

including the slow ice sheet feedback. However, here one must be cautious in

deciding “cause and effect” factors. Large fluctuations in the size of the Antarctic

ice sheet have occurred, possibly related to temporal variations of plate tectonics

and outgassing rates. The relatively constant atmospheric CO2 amount of the past

20 My implies a near balance of global outgassing and weather rates over that

period.

Knowledge of Cenozoic CO2 is limited to imprecise proxy measures except

for recent ice core data. There are discrepancies among different proxy measures,

and even between different investigators using the same proxy method. Nevertheless,

the proxy data indicate that CO2 was of the order of 1000 ppm in the early

Cenozoic but <500 ppm in the last 20 My – we must keep in mind that these are

indirectly derived!!! The entire Cenozoic climate forcing history is implied by the

temperature reconstruction, assuming a fast-feedback sensitivity of ¾°C per

W/m2. Subtracting the solar and surface albedo forcings, the latter from ice sheet

area vs. time

8.5 Global Warming!!!

Climate model projections summarized by the IPCC indicate that average

global surface temperature will likely rise a further 1.1 to 6.4 °C during the twenty-

first century. The range of values results from the use of differing scenarios of

future GHG emissions as well as models with differing climate sensitivity. From

these they expressed that warming and sea level rise are expected to continue for

more than a thousand years even if GHG levels are stabilized. The delay in reaching

equilibrium is a result of the large heat capacity of the Oceans. They further

postulated that increasing global temperature will cause sea level to rise, and is

expected to increase the intensity of extreme weather events and to change the

amount and pattern of precipitation; changes in agricultural yields, trade routes,

glacier retreat, species extinctions and increases in the ranges of disease vectors.

Global average temperature has increased by 0.75 °C (1.35 °F) relative to

the period 1860–1900. It is also reported that since 1979, land temperatures have

increased about twice as fast as the Ocean temperatures (0.25 °C per decade

against 0.13 °C per decade). Temperatures in the lower troposphere have increased

between 0.12 and 0.22 °C (0.22 and 0.4 °F) per decade since 1979, according to

satellite temperature measurements. Temperature is believed to have been relatively

stable over the one or two thousand years before 1850, with possibly regional

fluctuations such as the Medieval Warm Period or the Little Ice Age.


The observed surface global & hemispheres average temperature patterns

(Figure 8f) show cooler in the Southern Hemisphere with less land area compared

to Northern Hemisphere. Figure 8g presents the satellite & upper air balloon

global average temperature data series. The satellite data series cover both land

and Ocean areas as presented by NASA for the past two decades did not indicate

rise in the global surface temperatures & the upper air balloon observational data

followed in between the satellite and surface observations (Reddy, 2007a). It appears

that the satellite data series were modified latter!!! The average global surface

observed data presented a rise that too in a modulated form presenting ups-and-

downs (Figure 8f), which is not seen in model predicted temperature pattern

(Figure 8a) or in carbon dioxide data series (Figures 8b). This means, the current

climate models neither produce a good match to observations of global temperature

changes over the last century nor simulate all aspects of climate. These models do

not unambiguously attribute the warming that occurred from around 1910 to

1945 to either natural variation or human effects; however, they suggest that the

warming since 1975 is dominated by man-made GHG emissions but far from

observed pattern, which means the models lack clarity on the influence of GHGs

on temperature raise.

A recent report issued by the U.S. Climate Change Science Program

concluded that over the 25-year satellite record, the surface and mid-troposphere

have both warmed by approximately 0.15°C per decade – contrary to earlier

presentation (Figure 8g) —. Global warming deniers had frequently challenged the

reality of human-induced global warming and the reliability of climate models by

citing previously reported discrepancies between the amounts of warming at the

surface compared to the amount of warming higher in the atmosphere. The original

discrepancies were reported by John Christy, Roy Spencer and their team at the

University of Alabama-Huntsville based on microwave emissions from the atmosphere

recorded by satellites. But this argument is invalidated once errors in satellite and

radiosonde data have been identified and corrected; and new temperature time

series for the surface and atmosphere are consistent with each other. The University

of Alabama-Huntsville team also acknowledged their previous errors in late 2005.

This reconciliation of previous discrepancies led to an article in Science titled “No

Doubt About It, the World is Warming.” At an international tropical meteorology

conference in India, such a scene was repeated – the group engaged in the collection

of satellite data said that we are still in the process of working out to put the data

in right perspective but another group presented results in practical perspective

inferring great things. In the conference I put the question, then who is correct

and who is wrong but both the groups kept quite. That is if it is not serving their

purpose or not fitting into their models, they manipulate data. It is very difficult to

prove who is correct!!! This is rarely possible in the observed surface data. Any

manipulations can be easily detected.

A study by David Douglass, John Christy, Benjamin Pearson and Fred Singer

comparing the composite output of 22 leading global climate models with actual

climate data finds that the models do not accurately predict observed changes to


the temperature profile in the tropical troposphere. The authors note that their

conclusions contrast strongly with those of publications based on essentially the

same data. It is argued that the detailed causes of the recent warming

remain an active field of research.

IPCC is simply thrusting on the world community some thing that is not

scientifically proved beyond doubt. Some other hypotheses departing from the

consensus view have been suggested to explain most of the temperature increase.

One such hypothesis proposes that warming may be the result of variations in

solar activity. None of the effecting factors are instantaneous. As with any field of

scientific study, there are uncertainties associated with the global warming. This

does not imply that scientists do not have confidence in many aspects of climate

science. Some aspects of the science are known with virtual certainty, because

they are based on well-known physical laws and documented trends. Current

understanding of many other aspects of climate change ranges from “very likely”

to “uncertain”. Remaining scientific uncertainties include the amount of warming

expected in the future, and how warming and related changes will vary from

region to region around the Globe; most national governments have signed and

ratified the Kyoto Protocol aimed at reducing GHG emissions. It was noted that

even if GHGs were stabilized at 2000 levels, a further warming of about 0.5 °C

would still occur!!! Important scientific questions remain about how much warming

will occur, how fast it will occur, and how the warming will affect the rest of the

climate system including precipitation patterns and storms.

Answering these questions will require advances in scientific knowledge in

a number of areas, namely improving understanding of natural climatic variations,

changes in the Sun’s energy, land-use changes, the warming or cooling effects of

pollutant aerosols, and the impacts of changing humidity and cloud cover;

determining the relative contribution to climate change of human activities and

natural causes; projecting future GHG emissions and how the climate system will

respond within a narrow range; improving understanding of the potential for rapid

or abrupt climatic change; etc. Finally it is essential to present the realistic numerical

impact of GHGs on temperature!!!

Additionally (from IPCC, 2007) that “The warming trend is seen in both

daily maximum and minimum temperatures, with minimum temperatures increasing

at a faster rate than maximum temperatures. Land areas have tended to warm

faster than the Ocean areas and the winter months have warmed faster than

summer months. Widespread reductions in the number of days below freezing

occurred during the latter half of the 20th century in the United States as well as

most land areas of the Northern Hemisphere and areas of the Southern Hemisphere.

Average temperatures in the Arctic have increased at almost twice the global rate

in the past 100 years”. These observations, when looked in the meteorological

context present a different cause for the increase in night temperatures (minimum

temperature) such as heat island effect..


It is reported that the sea temperatures increase more slowly than those on

land both because of the larger effective heat capacity of the Oceans and because

the Ocean can lose heat by evaporation more readily than the land. The Northern

Hemisphere has more land than the Southern Hemisphere, so it warms faster. The

Northern Hemisphere also has extensive areas of seasonal snow and sea-ice cover

subject to the ice-albedo feedback. More GHGs are emitted in the Northern

Hemisphere than Southern Hemisphere. It is stated that this does not contribute

to the difference in warming because the major GHGs persist long enough to mix

between hemispheres. However, the network and accuracy of surface data are

quite different in the two hemispheres and yet not many differences are noted in

the temperature trend.

Based on estimates by NASA’s Goddard Institute for Space Studies, 2005

was the warmest year since reliable, widespread instrumental measurements became

available in the late 1800s, exceeding the previous record set in 1998 by a few

hundredths of a degree. Estimates prepared by the WMO and the Climate Research

Unit concluded that 2005 was the second warmest year, behind 1998. Temperatures

in 1998 were unusually warm because the strongest El Nino in the past century

occurred during that year. It is also reported that since the mid 1970s, the average

surface temperature has warmed about 1°F. The Earth’s surface is currently warming

at a rate of about 0.32ºF/decade or 3.2°F/century. The eight warmest years on

record (since 1850) have all occurred since 1998, with the warmest year being

2005.

Anthropogenic emissions of other pollutants—notably sulfate aerosols—

can exert a cooling effect by increasing the reflection of incoming sunlight. This

partially accounts for the cooling seen in the temperature record in the middle of

the twentieth century, though the cooling may also be due in part to natural

variability. James Hansen and colleagues have proposed that the effects of the

products of fossil fuel combustion—CO2 and aerosols—have largely offset one

another, so that warming in recent decades has been driven mainly by non-CO2

GHGs. Paleoclimatologist William Ruddiman has argued that human influence on

the global climate began around 8,000 years ago with the start of forest clearing

to provide land for agriculture and 5,000 years ago with the start of Asian rice

irrigation. Ruddiman’s interpretation of the historical record, with respect to the

methane data, has been disputed. The methane vs carbon dioxide issue in global

warming took political overtones of developed vs developing world.

From these it is clear that the global warming theory put forth by IPCC

under the disguise of “majority” theory needs re-look. IPCC must come up with

the facts that how much of the global warming is due to anthropogenic greenhouse

gases and how much is due to causes in built in nature & others. This does not

mean that we must encourage release of greenhouse gases into the atmosphere.

But it is to say that we must not look at western system of lopsided argument but

look at developing countries stand point where the direct impact of these pollutants

on life-forms. Give top priority in controlling pollution that have direct impact on

health of life-forms. This has serious repercussions on the poverty eradication


system in developing countries with high population pressure with low infrastructure

facilities.

8.6 Exploitation on the name of GW!!!

This is dealt in terms of agriculture as an example, which is vital issue in

developing countries to meet their food & other needs. Using global warming as a

means to exploit developing countries agriculture is in a critical stage. Unless the

exploitation is stopped now, this may through the developing countries economy

in doldrums. Let us see how to stop this.

Each agricultural species has an area of geographical adaptation where its’

climatic requirements are best met. The limits vary according to individual species.

Individually or in combination the environmental factors produce significant changes

in a biological cycle, which may be either detrimental or beneficial. The two biological

processes that are influenced by weather parameters are crop development and

growth. Sometimes these processes are hindered by unusual factors such as

insects/pests/diseases on the one hand and frost, hail, floods, strong winds, excess

radiation or temperature, cyclones, manmade factors on the other. These by their

intensity may cause death of the species and their frequency renders its cultivation

uneconomical. The former type again relates to weather/climate on the one hand

and the soil on the other. That is, weather influences the degree of interaction

between crop and insects/pests/diseases.

Reddy (1993) presented a review of models related to the estimation of

crop development and crop growth. The two important continuous and periodic

elements that affect development are temperature and photoperiod. In addition to

these two, relative humidity — atmospheric dryness, soil humidity – soil dryness

(related to soil moisture, soil temperature, soil type), soil fertility, plant – population

& agronomic practices, etc —, affect the crop development and thereby crop

growth. Here through proper selection/breeding the temperature and photoperiod

factors can be manipulated to a maximum extent (Reddy, et. al., 1984].

The basic weakness in whole of this exercise is in relation to expected

global warming and its’ consequent impacts but failed to take note of “even if

there is no global warming there is an absolute high risk to life farms on the Earth

due to direct impact of the pollution & pollutants, that costs billions of US# even

at short-term, leave alone the long-term impacts”. Unfortunately, IPCC is engaged

in this destructive mode and it is the duty of individual nations to look in to this

angle of climate change. Under these circumstances the middlemen-the corporate

giants are exploiting the third world countries. Gene Giants Grab “Climate Genes”:

Amid Global Food Crisis, Biotech Companies are exposed as Climate Change

Profiteers. A report released by Canadian-based civil society organization, ETC

Group, reveals that the world’s largest seed and agrochemical corporations are

stockpiling hundreds of monopoly “patents” on genes in plants that the companies

will market as crops genetically engineered to withstand environmental stresses

associated with climate change - including drought, heat, cold, floods, saline

soils, and more. ETC Group’s report warns that - rather than a solution for confronting


climate change - the promise of so-called “climate-ready” crops will be used to

drive farmers and governments onto a proprietary biotech platform. “In the face of

climate chaos and a deepening world food crisis, the ”Gene Giants” are gearing up

for a PR offensive to re-brand themselves as climate saviors,” says Hope Shand,

Research Director of ETC Group. “The companies hope to convince governments

and reluctant consumers that genetic engineering is the essential adaptation

strategy to insure agricultural productivity. Monopoly control of crop genes is a

bad idea under any circumstances - but during a global food emergency with

climate change looming - it’s unacceptable and must be challenged.” According

to ETC Group’s report, Patenting “Climate Genes”...And Capturing the Climate

Agenda, Monsanto, BASF, DuPont, Syngenta, Bayer and Dow - along with biotech

partners such as Mendel, Ceres, Evogene and more - have filed 532 patent

documents on genes related to environmental stress tolerance at patent offices

around the world. A list of 55 patent families (subsuming the 532 patent grants

and applications) is appended to the report. “The emphasis on genetically

engineered, so-called ‘climate-ready’ crops will divert resources from affordable,

decentralized approaches to cope with changing climate. Patents will concentrate

corporate power, drive up costs, inhibit independent research and further undermine

the rights of farmers to save and exchange seeds,” explains Shand. “Globally, the

top 10 seed corporations already control 57% of commercial seed sales. This is a

bid to capture as much of the rest of the market as possible.”

ETC Group calls on governments at the UN Biodiversity Convention (CBD) in

Bonn, Germany to suspend immediately all patents on so-called “climate ready”

crop genes and traits. We also call for a full investigation, including the social and

environmental impacts of these new, un-tested varieties. Further, governments

meeting in Bonn should identify and eliminate policies such as restrictive seed

laws, intellectual property regimes, contracts and trade agreements that are barriers

to farmer plant breeding, seed saving and exchange. “The world has already

recognized that we are in a food crisis and a climate ‘state of emergency,’” notes

Pat Mooney, ETC Group’s Executive Director. “In this ‘state of emergency’ farmers

must be given all the freedom and resources they need to get us through this

crisis,” Mooney adds.

According to ETC Group, many of the patent claims are unprecedented in

scope because a single patent may claim several different environmental (abiotic)

stress traits. In addition, some patent claims extend not just to abiotic stress

tolerance in a single engineered plant species - but also to a substantially similar

genetic sequence in virtually all engineered food crops. The corporate grab extends

beyond the U.S. and Europe. Patent offices in major food producing countries

such as Argentina, Australia, Brazil, Canada, China, Mexico and South Africa are

also swamped with patent filings. Monsanto (the world’s largest seed company)

and BASF (the world’s largest chemical firm) have entered into a colossal $1.5

billion partnership to engineer stress tolerant plants. “Together,” adds Kathy Jo

Wetter of ETC Group, “the two companies account for nearly half of the patent

families related to engineered stress tolerance identified by ETC Group. If we


include their smaller biotech partners like Ceres and Mendel, Monsanto and BASF

have a part in almost two-thirds of the so- called ‘climate-ready’ germplasm”.

“Technological silver bullets - especially patented ones - will not provide the

adaptation strategies that small farmers need to survive in the face of climate

change,” says ETC Group’s Jim Thomas. Climate scientists predict that marginalized

farming communities in the global South - those who have contributed least to

global greenhouse emissions - are among the most severely threatened by climate

chaos created by the world’s richest countries. “The South is already being trampled

by the North’s super-sized carbon footprint. Will farming communities now be

stampeded by the Gene Giants’ climate change profiteering? “ asks Thomas.

For the Gene Giants, the focus on “climate genes” is a golden opportunity

to push genetically engineered crops as “green” and climate-friendly. Biotech seeds

will no longer be marketed as a choice, but as a necessity. Given the state of

emergency in food and agriculture, governments will be pressured to overlook bio-

safety regulations and to accept dangerous technologies such as Terminator that

have been rejected by the international community. (Despite a U.N. moratorium on

Terminator seeds, the biotech industry argues that genetic seed sterilization will

make biotech crops safer by containing gene flow from engineered crops and

trees.

The basic question now to be answered is: What to be the solution to

counter this trend of Geni-Gaints conspiracy of “patenting”? Here are some points

that were submitted to Hon’ble Prime Minister of India: This year the country is

facing unprecedented shortages in food supply. The basic question that arises is:

Why? And how to stop such recurrences in future? Around 60% of the population

in India still depends upon “directly or indirectly” on agriculture. More than 60%

of Indian agriculture is at the mercy of “Rain God”. Lacks of acres of fertile

agriculture lands are/were affected by pollution & indiscriminately allocation to

SEZs, as against the laws. The “floods and droughts” are common every year in

one part of the country or the other integrated with climatic cycles in Indian

rainfall. With the ever-increasing population, disproportionate to our agricultural

production, the food needs are increasing with new lifestyle in which dry-land

crops suffered a lot, which are the staple food of millions from centuries. Farmers

are looking at high risk-cash crops, which is a bad “cropping pattern practices”

against the local prevailing conditions. This year, due to un-seasonal rains farmers

suffered severe monetary losses as well thus, causing shortages in food grains due

to lack of storage & drying facilities.

The 1960s green revolution technology was based on few years experience

of a few scientists, interwoven with the vested interests of few Western MNCs

created new problems hitherto unknown and thus affecting environment – soil &

human, animal, plant life and health – and increased the cost of production. All

these factors were not accounted into production costs. Though the Indian

agriculture has grown by leaps and bounds in quantity but failed to achieve the

quality of traditional food. To understand this fallacy in green revolution technology,


it took forty years. This technology was successful under irrigation, projects

developed at huge costs. The main beneficiaries of this system were the MNCs

involved in the chemical inputs trade under high subsides, the other major input in

to the technology. Even with all these ill affects, the production growth curve has

flattened after around 1984. This is basically because; Western/MNCs interests

cloud our scientists and scientific institutions. Our Academies of sciences are

under the control of the same groups. The top bosses, after retirement joining

them. Most unfortunately, the farmers’ federations also joined this bandwagon

harming the agriculture environment through helping the illegal testing of un-

approved hazardous technologies in farmers’ fields. In this, our bureaucrats are

also not far behind the scientific community (Reddy, 2006a).

The success of green revolution was possible with irrigation, as the diffusion

of Technologies was possible only through irrigation. Because of this the rainfed

agriculture has not recorded the success as that was recorded in irrigated agriculture

with the stagnation in irrigation potential but increased the level of risk. Thus, the

gulf between the irrigated agriculture and rainfed agriculture is increasing and this

is amplified through step motherly treatment for rainfed food grains under subsidized

schemes of PDS, where rice is supplied neglecting coarse grains produced under

rainfed condition. This is one other reason for food shortages. Area under bio-fuel

is not an important issue like in Mexico, as fertile lands are not used for this

purpose but aquaculture is an important issue in India as fertile lands are under

destruction. The other important issue is the destruction of forestlands is in rampant

and cause the reduction in rainfall with increased temperature regimes. Thus,

water requirements of crops are increasing. We are not utilizing available water

resources effectively due to inter-state disputes along with vested interest groups

creating legal disputes.

The four main Western MNCs minted billions of US$ through the sale of

chemical inputs under the disguise of green revolution technology have come up

with a new technology, known as genetically modified seed technology that works

under the same conditions as that of green revolution as they are no more gaining

with green revolution technology. Scientists like Noble prize winner Dr. Norman

Borlaugh, who is behind the green revolution technology, now writes letters to

Indian scientists in support of genetically modified crops stating that this is the

technology to over come the poverty as an agent of Western MNCs, Indian retired

scientists who have the clout with government in turn planted these letters in

Indian media. When the entire world was against the Terminator Technology, the

former D.G. of ICAR, Dr. R. S. Paroda said that it is a good technology to eradicate

Parthanium, entered India with PL-480 Wheat. This is like “Scratching the head

with Fire”. Biotechnology companies often claim that GM organisms are essential

scientific breakthroughs needed to feed the World, protect the environment, and

reduce poverty in developing countries. Unfortunately, our own agriculture top

boss, the ICAR D.G., Dr. Mangal Roy, echoes this at a biotechnology meet organized

by FICCI in New Delhi on 16th September 2007. At the same time he argues that


GM food has more resistance power in humans against diseases as well require

less chemical fertilizers & less water. This is exactly opposite to what the scientific

out come in India and elsewhere in the world including in USA. Most of the

innovations in agricultural biotechnology have been profit-driven rather than need

driven. The real thrust of the GM industry is not to make third world agriculture

more productive, but rather generate profits. These technologies respond to the

need of biotechnology companies to intensify farmers’ dependence upon seeds

protected by the so-called “IPR”, which conflict directly with age-old rights of

farmers to reproduce or store seeds. Still there are many unanswered ecological

questions – bio-safety, food safety, ethical, etc aspects — regarding the impact of

transgenic crops.

The green revolution technology created health hazards to life forms hither

to unkown through food, water, soil & air pollution. To cure these diseases

established highly polluting [soil, air & water] industries that created new diseases.

The vicious circle is moving with increased population & changed life style. This

area of creating GHGs is not received as much as that of power production. Here,

developed countries are polluting developing countries by encouraging out sourcing

production. Here think globally and act locally plays the major role but

unfortunately, the slogan adopted is “think locally and act globally”. Some powerful

MNCs are vigorously trying to bring in corporate agriculture. As a prelude to this

they are behind the price rise through encouraging hording, illegal export, etc.

Opposition political parties also joined this bandwagon. A media report says that

thousands of tons of rice is exported illegally; farmers are not able to get Rs. 3 per

kg for onions but in the market they are fetching Rs. 17 per kg. That is artificial

shortage is another part of the price rise game.

The research priorities of government sponsored agriculture research institute

such, as CSIR must change to meet the local needs of the farmers and to make

Indian Agriculture Sustainable. At present they are carrying out the tasks what

their Western bosses/MNCs wanted them to do!!! Because of this tendency of our

research Institutions in India made the glut in Indian Agriculture. Prior to green

revolution the farmers used indigenous technologies evolved over hundreds and

thousands of years experience and passed it on to generation after generation.

These technologies were weather & soil based farming systems that include crops

& cropping pattern, agricultural practices, land & water management practices.

These are said to be “Golden Days” in the history of Indian farming. No pollution,

no worry about seed adulteration, fertilizer adulteration as they used the good

grain as seed and compost of farmyard manure as fertilizer. Though the yields are

low, the quality of food was excellent. However, progressive farmers over different

parts of the country have shown that they can achieve yields better than the high

cost green revolution yields with traditional agriculture. Also, all over India different

research groups working with farming community have shown that this is possible

with organic farming.

(1) Firstly, our research institutions must collect the inventions of progressive

farmers and integrate them in to the agriculture system and propagate;


Co-operative farming: In Indian agriculture conditions, more than 90% of farmers

are within the 5 ha of cultivated area group and constitute more than 60% of the

cultivated area. Only around 40% of cultivated area receives irrigation and in this,

15 to 20% area gets water from dwindling groundwater sources by which the

cultivated area per pump has gone down dramatically and will continue as recharging

venues are being destroyed. These farmers face the major problem of adulteration

of seed, chemical inputs, loans, selling & storing the outputs, etc. Now, to improve

the condition of such farmers, the only way left under the present socio-economic-

political-bureaucratic scenario, is to group the farmers into co-operative farming

groups. Such system help in the effective utilization of water & energy resources,

input resources, subsidies/loans by government agencies and develop an effective

mechanism for sale and storage agriculture outputs. They can produce their own

seed and organic inputs and thus the cost of production could be reduced drastically

and thus improve the economy of the farmers and eliminate farmers suicides. Here

the groups can control the crops/cropping system or farming system that better

suits the prevailing conditions. In fact under the present conditions lacks of crores

given every year under loans, subsidies, and loans viewer system are going into

drain. To utilize them effectively, the only solution is co-operative farming. Also

this is the only way to stop farmers’ suicides. The problem must be talked in an

integrated manner rather than in isolation. This is possible under co-operative

farming.

(2) Secondly, adapt, under marginal, small and semi-medium farming sectors,

the system of co-operative farming under rainfed as well under well irrigation with

micro-irrigation system. This can be implemented through local MLAs & MPs;

Corporate agriculture is not a solution: Our bureaucracy is influenced by the

rich multinational companies and put forward the corporate farming as a solution

to food production to meet the growing population forgetting that the agriculture

is providing employment to more than 65% of population, directly and indirectly.

In fact the foundations were laid for such a system during the previous regime

itself. At present to some extent prices are under the control of government and

once the corporatism enter the scene the prices will be at their mercy that leads

severe poverty and mass suicides.

(3) Avoid Corporate Farming, which is a bad practice to the Indian agriculture

system;

Others

• Adapt farming systems practices to reduction of weather related risks and

those that better utilization of water resources;

• In the public distribution system (PDS) encourage giving coarse cereals at

the same level of subsidies as that of rice;

• Tank irrigation: To get a balanced growth at local and regional levels under

the prevailing climate & weather conditions top priority must be given to protect

and restore the areas under tank irrigation. This shall not only help the direct


irrigation but also improve indirect irrigation through wells/ bore-wells through

recharging-dwindling ground water. Watersheds and cloud seeding are futile

exercises and waste of public money in dry-areas of India with erratic &

undependable rainfall patterns. However, the government must complete irrigation

projects by clearing inter-state/judicial tangles. In agriculture sector the wasteful

expenditure to exchequer is too many that are sufficient to complete the irrigation

projects.

[4]. Give the responsibility of protecting and maintaining of tanks to the local

MLAs & MPs;

• Seed village programmes could be effectively implemented through

establishment of commodity boards for region specific important crops by linking

this with State Seed Corporation.

It is clear that the basic approach used in the global warming is to help

multinational western companies to mint money. To achieve this goal, IPCC became

a pawn in the hands of MNCs & Western rich nations. Developing countries must

not enter into this trap and should focus “think globally and act locally” to minimize

the health hazards and through which pollution & GHG could be minimized. This

is the best solution for developing countries to sustain the agriculture growth.


Chapter 9

Extreme Weather & Climate Events

9.1 Introduction

A 2001 report by the IPCC suggests that glacier retreat, ice shelf disruption

such as that of the Larsen Ice Shelf, Sea Level Rise, changes in rainfall patterns,

and increased intensity and frequency of extreme weather events, are being

attributed in part to global warming. One study predicts 18% to 35% of a sample

of 1,103 animals and plant species would be extinct by 2050, in relation to future

climate projections. Based on such reports, “India Today” magazine in its’ August

12, 2002 issue under cover story by Raj Chengappa reports mind boggling headlines,

such as: “This year’s wayward monsoon over India and freaky weather elsewhere

portend devastating climate changes as a result of global warming; Glaciers in the

Himalayas will recede by 2020 causing floods and then deserts; By 2015 rise in sea

levels will drown parts of Mumbai. Loss is Rs. 2,28,700 crore; Productivity of rice

and wheat crops will drop by 15 per cent in the next decade; Warmer climate will

cause major health problems such as the spread of dengue; All nations will be hit.

The US will be a dust bowl and Bangladesh will be swamped; etc”. By this way

fear psychosis is built in human mind and get hype.

9.2 Glacier Melting

It is a well-known fact that in the Hydrological Cycle (Figure 9a), the evaporated

water from Oceans that occupies two-thirds of globe and water bodies comes

back as rain & snow. Some of the processes involved in this cycle are briefly given

as:

• Evaporation is the change of state of water (a liquid) to water vapour (a

gas). On an average, about 47 inches (120 cm) is evaporated into the atmosphere

from the Ocean each year;

• Transpiration is evaporation of liquid water from plants and trees into the

atmosphere. About 90% of all water that enters the roots transpires into the

atmosphere;

• Sublimation is the process where ice and snow (a solid) change into water

vapour (a gas) without moving through the liquid phase;

• Condensation is the process where water vapour (a gas) changes back in to

water droplets (a liquid). This is when we begin to see clouds;

• Transportation is the movement of solid, liquid and gaseous water through

the atmosphere. Without this movement, the water evaporated over the Ocean

would not precipitate over land;

• Precipitation is water that falls to the Earth. Most precipitation falls as rain

but includes snow, sleet, drizzle, and hail. Around 313,000 mi3 (515,000 km3) of

water falls each year, mainly over the Ocean;


• Runoff is the variety of ways of which water moves over the Earth’s surface.

This comes from melting snow & rain;

• Infiltration is the movement of water into the ground from the surface.

Groundwater flow is the flow of water underground aquifers. The water may

return to the surface in springs or eventually seep into the Oceans. Plant uptake is

water taken from the ground water flow and soil moisture.

Reports suggest that each year about 8 mm of water from the entire surface

of the Oceans goes into the Antarctica and Greenland ice sheets as snowfall. If

no ice returned to the Oceans, sea level would drop by 8 mm every year. Although

approximately the same amount of water returns to the Ocean in icebergs and

from ice melting at the edges, scientists do not know which is greater – the ice

going in or the ice coming out. Reports also present that if all glaciers and ice

caps melt, the projected rise in sea level will be around 0.5 m. If the melting

includes the Antarctica and Greenland ice sheets, then the rise is more drastic

68.8 cm. Climate changes during 20th Century are estimated from modeling studies.

Estimates suggest that Greenland and Antarctica have contributed 0.0 to 0.5 mm/

year over the 20th Century as a result of long-term adjustment to the end of the

last ice age. It is reported, “sparse records indicate that glaciers have been retreating

since the early 1800s”. In the 1950s measurements began that allow the monitoring

of glacial mass balance.

The Times of India on March 22, 2008 presented two reports with the

headings “Himalayan tragedy awaits India and China, says study: Food crisis looms

large as rivers like Ganga & Yangtze may dry up” and “Gangotri shall live from here

to Eternity: Leading Indian scientists take a dim view of doomsayers who predict

the glacier that feeds the sacred Ganga will disappear due to global warming in

the next 40 years”.

The first report is based on an article of Lester Brown, who said “Mountain

Glaciers in the Himalayas and on the Tibet-Qinghai Plateau are melting and could

soon deprive the major rivers of India and China of the ice melt needed to sustain

them during the dry season. In the Ganges, the Yellow River and the Yangtze river

basins, where irrigated agriculture depends heavily on rivers, this loss of dry season

flows will shrink harvests”. Brown also referred in his article the IPCC report that

Himalayan Glaciers are receding rapidly and that many could melt entirely by

2035. If the giant Gangotri Glacier that supplies 70% of the Ganges flow during

the dry season disappears, it warned, the Ganges could become a seasonal river,

flowing during the rainy season but not during the summer dry season when

irrigation water needs are greatest”. The Ganga is the largest source of surface

water irrigation in India and the leading source of water for the 407 million people

living in the Gangetic basin, a population larger than any other single country

other than China. The Yellow River and Yangtze basins hold a similar position in

China.

In the second report, contrary to what prophets of doom contend, that

Gangotri will disappear in the next 30 to 40 years, some of India’s leading scientists


believe there’s no immediate or even medium term threat to the glacier that feeds

on of India’s greatest river, Ganga. India has 9575 glaciers, of which around 50 are

being monitored by the Geological Survey of India (GSI) on a regular basis. None

of these show a particularly high rate of retreat. Gangotri’s draw down – 20

meters per annum in the ‘70s – is now mere six meters a year. Bhagirath Khadak in

the Himalayas was retreating at 12 m annually but last year it didn’t retreat at all.

Machol in Jammu & Kashmir has showed no change since 1957. It is true of

Siachen and Kagriz in Ladakh, according to Geological Survey of India (GSI), V.K.

Raina, Chairman, Monitoring Committee on Himalayan Glaciology, Government of

India, at a conference in Lucknow University recently says that there was no

reason to press panic button based on Western analysis of melting Arctic glaciers.

He also further states that the Western estimates are true for regions around the

North Pole – but these glaciers open into the sea. In India, glaciers are situated

over 3500 m above the sea level. The Himalayas, in fact, are conductive for the

preservation of glaciers. Even if Gangotri retreats at 20 m per annum, it will last for

1,500 years. He further states that the doomsayers have based their claims of a

much shorter life of Gangotri on the basis of reduction in discharge of water from

the glacier into the Ganga, but glacier contributes only 25% to river discharge –

the remaining 75% depends on snowfall and rain water. In fact the discharge in to

Ganga increased in 2001 when there was heavy snowfall. Same is the case for this

year.

Dhruv Sen Singh, who teaches geology at Lucknow University and who was

part of India’s first scientific expedition to the Arctic in 2007 said, “Not only the

rate of retreat of Gangotri has decreased, in Leh, 123 years of temperature data

shows a cooling of 0.04 degrees per decade”. He adds that the 20 m rate of

retreat of Gangotri in the ‘70s wasn’t because of warming but because of the

cracking in the linear structure of the glacier at the snout. Then some of its

tributaries had become inactive and were contributing water instead of ice. These

factors keep changing in the natural course leading to fluctuation in the rate of

retreat of high mountain glaciers.

In March 2006, Science magazine led with the cover “Climate Change —

Breaking the Ice.” The edition included articles covering important new research on

warming at both poles that is leading to changes in the ice system. These changes

are occurring faster than previously observed or expected, therefore indicating

that both the Arctic and Antarctic may be approaching a “tipping point” after

which dangerous transformations will become unavoidable. Markers of such changes

are visible in Greenland and in the Antarctic ice sheet, both of which are melting

and thinning more rapidly than in the past. Velicogna and Wahr found that the

mass of the Antarctic ice sheet has decreased significantly since 2002. A similar

rapid loss of ice mass has been shown in the Arctic, where Rignot and Kanagaratnam

found that the loss of mass from the Greenland ice sheet doubled between 1996

and 2005 to 224 ± 41 cubic kilometers (54 ± 10 cubic miles) per year. For

comparison, the city of Los Angeles uses 1 cubic kilometers (0.23 cubic miles) of

water per year.


Records of past ice-sheet melting indicate that the rate of future melting

and the related sea-level rise could be faster than widely thought, according to

Overpeck et al. This recent study found that during the last interglacial period

approximately 130,000 to 127,000 years ago, sea level ranged from 4 meters to

more than 6 meters higher than today. Climate models project that by 2100, the

high northern latitudes will be as warm, or warmer, than they were during the last

interglacial period. Unless we curb heat-trapping emissions, temperatures in the

late 21st century would be warm enough to melt at least large portions of Greenland

and quite probably portions of West Antarctica. Millions of people would be

vulnerable to flooding and displacement from the resulting sea level rise, and the

economic loss associated with coastal inundation would be devastating.

Another study looked at the link between melting ice fields and rising sea

levels. Otto-Bliesner et al. quantified what melting from Greenland and other Arctic

ice fields contributed to sea level rise during the last interglacial period. They

evaluated ice cap retreat by analyzing results from a global climate model, a dynamic

ice sheet model and paleoclimatic data. They found that melting in the western

Arctic ice fields and Greenland contributed between 2.2 meters and 3.4 meters of

sea level rise during the last interglacial period. While this was due to natural

variations in global climate, human-induced global warming over the next century

could lead to similar, substantial impacts on the polar environment.

Another report says, “But it’s not just the ice system that is changing.

Changes in the permafrost, or the permanently frozen ground, also reflect a warming

trend in the Arctic”. Recent runs of the National Center for Atmospheric Research’s

Community Climate System Model project that under business-as-usual greenhouse

gas emission scenarios, there will be an up to 80 percent decline in near-surface

permafrost by 2100. Even if the extent of permafrost melt is not as large as projected

by this scenario and model, these results imply that large-scale changes in permafrost

will occur in the future. If large-scale permafrost melting occurs, it may result in

the rapid release of large quantities of methane, a potent global warming pollutant.

A report says, “Scientists at the National Snow and Ice Data Center released

results showing that March 2006 had the lowest Arctic wintertime sea ice coverage

since 1979, the beginning of the satellite record. March sea ice represents the

maximum cover for the year, and the record low in 2006 is particularly significant

since it illustrates that for two years running, Arctic sea ice has failed to recover to

its previous maximum levels during the winter months. The long-term mean March

sea ice extent is 6.06 million square miles, whereas 2005 and 2006 set two new

“record” lows at 5.72 million square miles and 5.60 million square miles, respectively.

Compared to the long-term average wintertime sea ice level, the 2006-drop is

approximately equivalent to three times the area of California. Although the decline

in winter sea ice — the annual maximum — is not as pronounced as that of

summer sea ice decline — the annual minimum — low winter sea ice means that

the ice is freezing later in the fall and growing at a slower pace during the winter.

We can expect this summer to continue the trend of all-time lows in sea ice

extent. In fact, a study by Stroeve et al. recently found that four out of the five


lowest years of sea ice coverage have occurred since 2002. This accelerated decline

in summertime sea ice led Overpeck and his colleagues to conclude that the Arctic

could be completely free of summer sea ice well before the end of this century, a

state that has not occurred over at least the last million years”.

New research from multiple groups suggests that current climate models

may underestimate global warming projections because of a failure to account for

positive feedback. For instance, higher temperatures may lead to increased releases

— or reduced uptake of — carbon dioxide and/or methane by the Ocean, forests

and soils. This self-reinforcing cycle may not be fully accounted for in climate

models, and until recently, few studies tried to quantify it. Torn and Harte have

now found that by incorporating the carbon dioxide and methane positive feedback,

the warming associated with doubling of carbon dioxide due to human activities

is amplified from the range of 1.5 - 4.5°C to 1.6 - 6.0°C. Similarly, Scheffer and

his colleagues found that the century-scale positive feedback of rising temperatures

on atmospheric carbon dioxide concentrations will further enhance warming by an

extra 15 to 78 percent. Although both groups of researchers recognize the

limitations and uncertainties of their projections, their independent results, which

use different methods, suggest that warming over the coming century may in fact

be greater than recent trends and could be larger than that projected by the

Intergovernmental Panel on Climate Change. Additional studies found evidence

that feedback mechanisms have amplified warming in the past. The Arctic Coring

Expedition analyzed sediments from the Palaeocene/Eocene thermal maximum and

found that polar temperatures during this period were more than 18°F warmer

than those predicted by current climate models and that the Arctic is capable of

warming to over 73°F and becoming ice free. This illustrates that higher-than-

modern greenhouse gas concentrations must have operated in conjunction with

additional feedback mechanisms, currently unaccounted for in climate models, to

intensify warming. Sluijs and his colleagues suspect that polar stratospheric

clouds and hurricane-induced ocean mixing could have lead to the high-

latitude warming and tropical cooling found in the records.

However, with all these contradicting findings, the glacier melt theory do

not, in fact, take into account the intensity of stress created by human activities

undertaken at these sources in the name of research, pilgrimage, tourism, sports

and other visits as well due to war related activities in addition to natural calamities

and natural rhythm that is present in nature, impact of Earthquakes, volcanic

eruptions, landslides, impact of outer space objects falling, etc. Thus the research

in this area is biased/flawed towards global warming giving minimal importance to

other factors. This needs rectification to get correct picture on glacial retreat due

to global warming by separating the effect of other factors on glacial retreat. This

aspect is researched very little!!! Also during glacial and interglacial periods the

increase or decrease in carbon dioxide concentrations in the atmosphere as revealed

from the paleoclimatological studies, primarily an after effect of increase or decrease

in temperature pattern and not vice-versa like the anthropogenic theory.


9.3 Sea Level Rise

As per the IPCC (2007), “sea levels are raising worldwide and along much

of the U.S. coast. Tide gauge measurements and satellite altimetry suggest that

sea level has risen worldwide approximately 4.8-8.8 inches (12-22 cm) during the

last century. A significant amount of sea level rise has likely resulted from the

observed warming of the atmosphere and the Oceans. The primary factors driving

current sea level rise include: the expansion of Ocean water caused by warmer

Ocean temperatures melting of mountain glaciers and small ice caps (to a lesser

extent) melting of the Greenland Ice Sheet and the Antarctic Ice Sheet. Other

factors may also be responsible for part of the historic rise in sea level, including

the pumping of ground water for human use, impoundment in reservoirs, wetland

drainage, deforestation, and the melting of polar ice sheets in response to the

warming that has occurred since the last ice age”.

Considering all of these factors, scientists still cannot account for the last

century’s sea level rise in its entirety. It is possible that some contributors to sea

level rise have not been documented or well quantified. The rate of sea level rise

increased during the 1993-2003 period compared with the longer-term average

(1961-2003), although it is unclear whether the faster rate reflects a short-term

variation or an increase in the long-term trend. While the global average sea level

rise of the 20th century was 4.4-8.8 inches, the sea level has not risen uniformly

from region to region. Sea level has been rising 2.0-3.0 mm per year along most of

the U.S. Atlantic and Gulf coasts. The rate of sea level rise varies from about 10

mm per year along the Louisiana Coast (due to land sinking), to a drop of a few

inches per decade in parts of Alaska (because land is rising).

Globally, Indonesia, Thailand, and Bangladesh are experiencing above-average

sea level rise. Northwestern Australia is experiencing below-average sea level

rise, a trend that is evident in much of the Ocean between western Australia and

East Africa. Most of the Pacific and Atlantic basins are experiencing average to

above-average sea level rise. Many coastal areas outside of the U.S., Europe and

Japan have too few tide gauges to be sure about long-term trends in regional sea

level rise. Studies of Roman wells in Caesarea and Roman piscinae in Italy indicate

that sea level stayed fairly constant from few hundred years. At TROPMET

Symposium held in Hyderabad, Dr. P.K. Das at the end of his award ceremony

delivered a lecture in which to my question he answered that out of the 12 sea

level observations along the Indian Coasts that at four locations the sea level

lowered and at the other 8 stations no change was noticed.

The IPCC (2007) expresses high confidence that the rate of observed sea

level rise increased from the mid 19th to the mid 20th century. During the 20th

century, sea level raised at an average rate 1.2-2.2 mm/year. Tide gauges show

little or no acceleration during the 20th century. Satellite measurements

estimate that sea level has been rising at a rate of 9 to 15 inches per century (2.4-

3.8 mm/yr) since 1993, more than 50% faster than the rate that tide gauges

estimate over the last century. According to the Free Encyclopedia (WIKIPEDIA],


“the sea level has risen more than 120 m since the peak of the last ice age about

18,000 years ago. However, only – 4 meters of this increase has occurred in the

last 6,000 years. From 3,000 years ago to the 19th Century the long-term change

was roughly 0.5 m at a rate of 0.1 to 0.2 mm/year. Since 1850, sea level has risen

again at 1 to 2 mm/year. Since 1992 satellite altimetry from TOPEX/Poseidon

suggests a rate of about 3 mm/year. Based on this they postulated that the

increased rates may indicate accelerating sea level change as a result of global

warming. During the 21st Century global warming models predict a sea level rise

of about 0.5 m”. Since 1992 the TOPEX and JASON Satellite programmes have

provided measurements of sea level change. The current data show a mean sea

level increase of 2.9 ± 0.4 mm/year. However, because of significant short-term

variability in sea level can occur, this recent increase does not necessarily indicate

a long-term acceleration in sea level changes. It is unclear whether this represents

an increase over the last decades; variability; or problems with Satellite calibration.

However, none of these studies looked into changes due to tectonic movements

inside the Earth.

IPCC predicts in sea level rise using models that by 2100 global warming will

lead to a sea level rise of 110 to 800 mm. Rejecting some of IPCC assumptions,

Morner (2004) has argued that sea level rise will not exceed 200 mm, within a

range of either + 100 to – 100 mm or +50 to ± 150 mm depending upon

assumptions. This means, the rise varies between 0 to 200 mm and –100 to 200

mm. Shall we accept such wide range of data as realistic or reject it? In science

the acceptable range is ± 10%, at the maximum. Most of these speculative increases

in sea level are beyond the observational error ranges. Because of this the ranges

present different groups under different measurement modes presents un-realistic

high variations that are not statistically or scientifically significant.

There are several types of information on sea level rise, which includes model

estimates, tide-gauze system observations, satellite altimetry observations, etc.

There are several issues involved in resolving the findings because they may be

short-term rise or adjustment of long-term ice ages, etc. Thus it became a puzzle

and unclear whether the so-called increase over the last decades is variability or

problems with tide-gauge/satellite calibration, lacunae in model formulations, etc

or due to tectonic movements. Thus sea level rise also traveling in the same boat

as global warming! That is, sea level may be rising, lowering and no change at all.

9.4 Extreme Events in Rainfall & Cyclone

9.4.1 Precipitation

IPCC (2007) proposes, “Increasing temperatures tend to increase evaporation,

which leads to more precipitation. As average global temperatures have risen,

average global precipitation has also increased”. IPCC also presented that

“Precipitation has generally increased over land north of 30°N from 1900-2005,

but has mostly declined over the tropics since the 1970s. Globally there has been

no statistically significant overall trend in precipitation over the past century,

although trends have widely by region and over time. It has become significantly


wetter in eastern parts of North and South America, northern Europe, and northern

and central Asia, but drier in the Sahel, the Mediterranean, southern Africa and

parts of southern Asia. Changes in precipitation and evaporation over the Oceans

are suggested by freshening of mid- and high-latitude waters (implying more

precipitation), along with increased salinity in low-latitude waters (implying less

precipitation and/or more evaporation).

The results summarized in Chapter 6 counters some of these observations.

There are significant systematic patterns in rainfall data series over different parts

of the globe. They also present a system in their variations with latitude, longitude,

land-sea, etc. These patterns clearly indicate that the rainfall is currently high over

certain parts of the glove and it is lower in certain other parts. However, these are

modified in association with the degree of ecological changes in a given region.

On the contrary, there is no evidence to prove that the changes in precipitation are

associated with global warming. See the Figure 6h standardized time series of

rainfall anomalies for the 20th century and a century period of the GFDL model

simulation containing the driest episode. The increased evaporation causes increased

rainfall is a false theory/logic – it is like wall is white and cow is white and

therefore wall is cow. Evaporation is not only relates to temperature factor but

also several other meteorological, orographic/topographic, land-sea-elevation factors

along with relative humidity (soil & atmosphere), wind, etc (Penman, 1948).

Evaporation changes with irrigation/spread of water bodies, as well. Also change

with land-use/land-cover changes. That is evaporation changes drastically with

“ecological changes” (Reddy, 1983c).

Generally, evaporation changes with precipitation but not vice-versa. Also

less than 1-degree change in temperature far smaller than the seasonal change

observed over different parts as well El-Nino/La-Nino factor that change evaporation.

Therefore, there is an urgency to look into the patterns presented in Chapter 6 by

adding the latest data of recent decades. This needs as a first step collect all such

information from local, regional, national studies world over. They play critical role

in agricultural policy decisions at national and global level (Reddy, 1993, 2002,

2006b & 2007].

9.4.2 Cyclonic storms

There is large natural variability in the intensity and frequency of mid latitude

storms and associated features such as thunderstorms, hail events and tornadoes.

To date, there is no long-term evidence of systematic changes in these types of

events over the course of the past 100 years (IPCC, 2007). It also says, “Analyses

of severe storms are complicated by factors including the localized nature of the

events, inconsistency in data observation methods, and the limited areas in which

studies have been performed. The frequency and intensity of tropical storm systems

have also varied over the 20th century on annual, decadal and multi-decadal time

scales. For example, in the Atlantic basin, the period from about 1995-2005 was

extremely active both in terms of the overall number of tropical storm systems

including hurricanes as well as in storm intensity. However, the two to three decades


prior to the mid-1990s were characterized as a relatively inactive period. Following

the Atlantic hurricane season of 2005, which set a record with 27 named storms,

a great deal of attention has focused on the relationship between hurricanes and

climate change”.

Numerous studies were published on possible linkages, with a range of

conclusions. To provide an updated assessment of the current state of knowledge

of the impact of global warming on tropical systems, the World Meteorological

Organization’s hurricane researchers published a consensus statement. Their

conclusions include (WMO, 2006): “Though there is evidence both for and against

the existence of a detectable anthropogenic signal in the tropical cyclone climate

record to date, no firm conclusion can be made on this point. There is general

agreement that no individual events in [2004 and 2005] can be attributed directly

to the recent warming of the global Oceans… it is possible that global warming

may have affected the 2004-2005 group of events as a whole. It is only a

presumption but not substantiated by facts”. All these highlight “Cat on the Wall”

proverb.

The newer IPCC Fourth Assessment summary reports says, “There is

observational evidence for an increase in intense tropical cyclone activity in the

North Atlantic Ocean since about 1970, in correlation with an increase in sea

surface temperature, but that the detection of long-term trends is complicated by

the quality of records prior to routine satellite observations”. The summary also

states that there is no clear trend in the annual worldwide number of tropical

cyclones. Unfortunately no scientist questions such inferences as year to year

variations in temperature are far higher [ten to twenty times] than the global

temperature raise by that time (less than 0.4 0C).

Reports say, “Accumulating evidence suggests that hurricanes are becoming

more intense due to global warming”. Research by Michael Mann from Penn State

and Kerry Emanuel from MIT suggests that warming of the tropical Atlantic due to

human activity is responsible for the recent increase in tropical cyclone activity.

They also concluded that there is no statistically significant evidence for natural

cycles, such as the Atlantic Multi-decadal Oscillation (AMO), playing a role in

long-term tropical North Atlantic sea-surface-temperature variations, which are

well correlated with tropical cyclone intensity. Mann and Emanuel found that the

dependency of tropical Atlantic sea surface temperature on the AMO is not

statistically robust, and that any trend recently accredited to the AMO may actually

be a result of global warming in conjunction with cooling associated with

tropospheric aerosol pollutants, such as sulfur dioxide and nitrogen oxide.

Two researchers from Purdue University also independently concluded that

mean annual tropical temperatures directly regulate the total power unleashed by

tropical cyclones. By using observational data from the European Centre for Medium-

Range Weather Forecasts Reanalysis Project, Sriver and Huber found that the

power dissipation of tropical cyclones (a measure of maximum wind speeds over

the duration of the storm) correlates with both air temperature and mean annual


tropical sea surface temperature, and that a substantial portion of variance in

globally integrated power dissipation can be attributed to changes in mean tropical

temperatures.

Analysis of the record-breaking 2005 hurricane season also reveals that

higher than usual global sea surface temperatures, a signature of global warming,

were responsible for the majority of the record high sea surface temperatures

documented in the tropical North Atlantic during the summer of 2005. Trenberth

and Shea attributed approximately half of the record warmth in the tropical North

Atlantic to global sea surface temperatures, whereas only a third of the warmth

was caused by the AMO and El Niño combined. As the background levels of

global sea surface temperatures continue to climb, we can expect greater hurricane

activity in future.

On the contrary, the history of cyclones/typhoons/hurricanes presents a

system in their occurrence patterns of severity and frequency (Reddy, 2007). In

USA according to NASA data, Hurricanes were severe in intensity during 1940s,

1950s and 1960s; they were less severe in intensity during 1970s, 1980s and

1990s. Now again they are severe in intensity similar to the period in 1940s-60s

(Figure 9b). This pattern is similar to the pattern observed in the All-India Southwest

Monsoon Rainfall (Reddy, 2003a, 2006b). The all-India Southwest Monsoon 60-

year cyclic pattern (Figure 6s) is presented by a sine curve along the horizontal

axis in Figure 9b.

Rajeevan, et al. (1999) observed, in 1959 to 1991 data, significant Inverse

relationship between Northwest Pacific activity as measured by typhoon days

during Summer months (June to September) and Indian Summer Monsoon Rainfall

(Table 12). That means the cyclonic activity in the Northwest Pacific are in opposition

to the Hurricane activity. Similar but opposite pattern of Hurricanes is evident in

the case of frequency of the cyclonic storms and depressions during Northeast

Monsoon season (October to December) in India during 1951-81(Indira, 1999) –

the frequency is less than 6 in the 1940s-60s and more than 6 in the 1970s-90s.

Table 12: Number of years under different groups of Typhoon days vs all-India

Summer Monsoon Rainfall during 1959-1991 [26-years]

Typhoon Days Number of years

Groups All-India Summer Monsoon Rainfall groups

Drought Normal Flood

Deficit 1 3 4

Normal 2 7 1

Excess 6 2 0

Note: Normal = 8 typhoon days; deficit/excess = <8/>8

typhoon days; Drought/Flood = < 10%/> 10% of normal rainfall

The frequency of occurrence of cyclones per year in Bay of Bengal during 1945 to

2000 (May to November) as presented by joint Typhoon Warning Centre shows a


drastic reduction around 1975s (Reddy, 2006b) — (Figure 9c). This followed the

Southwest Monsoon rainfall pattern in Andhra Pradesh. The Southwest Monsoon

rainfall 56-year cyclic pattern (Figure 6t) is presented by a sine curve along the

horizontal axis in Figure 9c.

Srivastava, et al. (2004) also presented this trend in the annual frequency of

cyclonic storms over the Arabian Sea and Bay of Bengal for the period 1961-2002.

Bay of Bengal storm activities presented a decreasing trend – in association with

this the Orissa rainfall presented a decreasing trend. This period coincides with

below the average rainfall cycle of Southwest Monsoon season of Andhra Pradesh

[1973 to 2001]. Andhra Pradesh rainfall is more associated with the frequency of

occurrence of the depressions/storms in the Bay of Bengal.

Jadhav (2004) computed the total number of low-pressure systems and

Depressions/storms for the monsoon months June to September for the period

1891-2000 – Rajendra Kumar (2004) data also followed this pattern.


However, the low-pressure systems are not confined to Andhra Pradesh

alone but are spread all over India while the majority of depressions/storms

influences the Andhra Pradesh rainfall. Though low-pressure systems do not present

a systematic variation, the depressions/storms followed the Southwest Monsoon

rainfall pattern of Andhra, wherein during the 1973 to 2001 presented lower number

compared to the previous 28-year period. Previous to this 28-year period again

presented lower number of depressions/storms. Though during 1973 to 2001

depressions/storms present a steep fall (Srivastava et al., 2004), the total number

of low pressure systems present no such fall. The steep fall in storms/depressions

present fall in rainfall along the East Coast but because of low-pressure systems

the rainfall over other parts haven’t sown such fall.

These clearly point out one thing that there is significant relationship among

cyclonic activity over different oceans-seas and rainfall patterns. There is a need to

look into this aspect by taking into account the solar-planetary system.

9.4.3 Un-usual events in Precipitation & Temperature

Precipitation: IPCC (2007) presented that “There has been an increase in the

number of heavy precipitation events over many areas during the past century, as

well as an increase since the 1970s in the prevalence of droughts—especially in

the tropics and subtropics. Observations compiled by NOAA’s National Climatic

Data Center show that over the contiguous U.S., total annual precipitation increased

at an average rate of 6.1 percent per century since 1900, although there was

considerable regional variability. The greatest increases came in the East North

Central climate region (11.6 percent per century) and the South (11.1 percent).

Hawaii was the only region to show a decrease (-9.25 percent). In the Northern

Hemisphere’s mid- and high latitudes, the precipitation trends are consistent with

climate model simulations that predict an increase in precipitation due to human-

induced warming. By contrast, the degree to which human influences have been

responsible for any variations in tropical precipitation patterns is not well understood

or agreed upon, as climate models often differ in their regional projections”.

Sharma & Sharma (2007) presented that “Barmer in Rajasthan, recorded

302 mm on September 1968 almost double the 160 mm rainfall of 22 August

2006. There was heavy rainfall in Jodhpur in 1979 and 1981”. Andhra Pradesh

(AP) comprises three meteorological sub-divisions, namely Coastal Andhra,

Rayalaseema and Telangana. Andhra Pradesh presents a typically unique pattern,

varying from wet to dry climates. The State receives rainfall from both the Southwest

and the Northeast Monsoons. With the cyclonic activity in both the monsoon

seasons, the rainfall over different parts of the State present highly variable patterns

both in time & space. In fact predominantly the rainfall is mainly associated with

cyclonic disturbances. With all these the climate presents dry or arid Anantapur to

Wet Adilabad.

As it is seen from Table 11 (Reddy, 2000a) that Andhra Pradesh receives

rainfall in two monsoon seasons, namely Southwest Monsoon (June to September]

and Northeast Monsoon [October to December].


Table 11: Average rainfall amounts & C.V.s in the three meteorologicalsub-divisions of AP during 1871-1990

Region Parameter SWM NEM Annual

India Mean, mm 852(78) 120(11) 1090

C.V., % 9.9 29.0 19.5

CA Mean, mm 507(52) 375(39) 971

C.V., % 22.2 38.8 19.8

T Mean, mm 722(80) 107(12) 899

C.V., % 23.5 60.3 21.7

R Mean, mm 422(60) 204(29) 709

C.V., % 28.8 41.9 21.6

Note: CA = Coastal Andhra, T = Telangana, R = Rayalaseema,SWM = Southwest Monsoon, NEM = Northeast Monsoon, C.V.coefficient of variation, number within the brockets refer to % ofSWM & NEM to Annual rainfall

The contribution of rainfall during these two monsoon seasons in threesub-divisions is quite different. During SWM Telangana region received 80% ofthe annual rainfall. These are reduced to 60% in Rayalaseema region and 52% inCoastal Andhra region. They are respectively 12, 29 & 39% during the NEM. Thespatial variation of drought risk presents 5 to 60% of the years, with the highestrisk in Anantapur region (Reddy, 1993).

The year-to-year variations in rainfall & onset dates of Southwest Monsoonare very high (Reddy, 2000a), which can be seen from the rainfall extremes(Table 12).

Table 12: Extreme events of rainfall & onset dates in AP during 1871-1994

Period L H E D

(mm/year) (mm/year)

Coastal Andhra 28/5/1925 24/6/1959

Annual 532/1891 1501/1990

SWM 309/1888 780/1978

NEM 88/1909 703/1994

Telangana 28/5/1925 24/6/1959

Annual 489/1920 1485/1893

SWM 371/1877 1186/1988

NEM 2/1988 310/1987

Rayalaseema 24/5/1933 24/6/1959

Annual 226/1876 1228/1874

SWM 192/1904 791/1878

NEM 12/1876 455/1946

Note: SWM = Southwest Monsoon, NEM = Northeast Monsoon, L = the

Lowest rainfall, H = the highest rainfall; and E = the earliest date &

D = delayed date of onset of monsoon rains


It is seen from Table 12, the highest and the lowest rainfall amounts received

during 1871 to 1994 [124 years] in the three meteorological sub-divisions of Andhra

Pradesh that in Telangana Sub-division the highest annual rainfall was received

during 1893 and the lowest annual rainfall was received during 1920; in the case

of Coastal Andhra they are during 1990 & 1891; and in the case of Rayalaseema

they are during 1874 & 1876. The figures for Southwest Monsoon and Northeast

Monsoon are quite different when compared to annual rainfall. In the last one-

decade the lowest values have not crossed the mark presented in Table 11 & 12

but the highest values crossed the mark as there is an increasing trend in rainfall

due to large changes in land-use pattern.

Munot (2004) presented an analysis of all-India Summer Monsoon rainfall in

terms of deficit and excess rainfall years during 1871-2001. The highest rainfall of

1020.3 mm, which is 19.9% above the mean rainfall of 850.8 mm, was received in

1961; after this, 18.0% was received in 1917; 16.6% in 1892; 15.6% in 1956; etc.

The lowest rainfall of 604.3 mm, which is 29.0% below the mean rainfall of 850.8

mm, was received in 1877; after this, 26.1% was received in 1899; 23.5% in 1918;

23.3% in 1972, etc.

Let us see the four years data of rainfall received in three Andhra Pradesh

sub-divisions (Reddy, 2003b) as % of average rainfall in Southwest Monsoon and

Northeast Monsoon (Table 13). In the case of Coastal Andhra the rainfall during

Southwest Monsoon varied between 59% and 143% and in the case of Northeast

Monsoon varied between 35% and 177%. The same in Telangana are 81% and

146%; 46% and 290% while they are 87% and 146%; 31% and 159% in

Rayalaseema. Quite large differences though followed the same pattern.

Table 13: % average rainfall in the three sub- Divisions of AP during 1987-1990

Year Rainfall in % of average

SW NE

CA T R CA T R

1987 59 81 90 177 290 159

1988 143 146 146 45 48 31

1989 142 139 145 35 46 47

1990 90 113 87 130 193 132

Note: SW = Southwest Monsoon; NE= Northeast Monsoon;

CA = Coastal Andhra; T = Telangana; and R = Rayalaseema

In the State of Andhra Pradesh in India during summer, heat waves are

common reaching as high as 50 oC. During 2008 May the heat wave prevailed for

several days along the South Coastal belt & Telangana, reaching as high as 45 oC

and above. Some of these conditions are associated with cyclonic disturbances in

the southern Bay of Bengal. During winter, when the Western Disturbances in

northwest India were pushed southward, Andhra Pradesh also experiences severe

cold weather or cold waves conditions. In Andhra Pradesh, the State Government


initiated cloud seeding programme in drier areas. Though the organizers of the

programme claimed in their reports submitted to the government that rainfall has

increased but in reality the rainfall has presented strong decrease in downwind

direction. I brought this to the notice of government with examples taken from the

seeding experiments. The technical committee advised the organizers not to seed

intensive synoptic systems even otherwise they give copious rainfall in areas in the

windward direction. But, the company executing the operation, invariably seed

such systems only, saying that “it is not binding on us as it is not the part of our

contract”. Therefore, if this programme continues there is a high possibility of

rainfall pattern may present drastic changes. This may have severe negative impact

on agriculture & water resources in the state in coming years.

In Andhra Pradesh both government sponsored and private and communists

sponsored destruction of forests are going on in several thousands of acres that

may also severely increase the temperatures and decrease the rainfall – researchers

showed there is considerable increase in rainfall & decrease in temperature in areas

where considerable area was brought under reforestation. Though, these are

countered somewhat by some of the irrigation projects and associated “increased

area” under water reservoirs & greenery, land use change from dry-land to wet-

land.

Mohan Lal Sahu (2004) data for Chattisgarh presents a mean summer

monsoon rainfall of 1232.2 mm. The highest rainfall of excess 47.8% of average

was recorded in 1961; following this in 1925 received 31.3%, 30.0% was received

in 1936, 27.4% in 1980, 24.0% in 1994. The lowest rainfall of deficit 29.1% was

received in 1987; following this 28.9% was received in 1941, 26.76% in 1974,

24.46% in 1966, 22.08% in 2000. The Cochin highest rainfall data along with

their year of occurrence in different months at daily & monthly interval presented

by Bindu & Rajan (2004) for the period 1901 to 2000 do not give the impression

that the unusual falls are associated with a particular period (Table 14).

Table 14: Monthly and daily highest rainfall of Cochin

Month 1 2 3 4 5 6

January 21.1 1921 13.3 1921 10 2.4

February 17.0 1984 9.0 1952 11 2.8

March 24.5 1960 12.6 1960 7 4.8

April 34.3 1908 16.2 1956 11 11.9

May 107.6 1933 25.3 1933 24 31.8

June 121.6 1912 34.7 1959 29 72.4

July 145.4 1968 21.4 1910 31 63.3

Augus 119.9 1931 15.6 1947 31 37.8

September 68.4 1988 11.6 1959 29 26.5

October 90.6 1932 23.2 1951 30 31.0

November 47.6 1966 15.4 1966 12 16.9

December 28.0 1972 15.5 1946 6 5.1


Note: 1 = average highest rainfall of the month, mm; 2 = year of the highest; 3

= average highest rainfall of the day, mm; 4 = year of the highest; 5 = average

rainy days of the month; 6 = average rainfall of the month, cm

Thapliyal, et al. (2004) observed that the magnitude and persistence of

changes are not large enough to conclude that the increase of extreme reflects a

non-stationary climate. As the skew-ness increases in the rainfall data the limits of

variation (% variations) also present higher values. These can’t be attributed to

unusual events. The skew-ness in the data series increases from a region to a

location, from annual to seasonal to monthly to weekly to daily to hourly data.

However, rainfall presents an increasing/decreasing trend over different parts of

the country based on the changes in local environment in addition to systematic

variations.

Temperature: The author developed concepts to estimate radiation over different

parts of the globe since 1971 (see Chapter 3). In this venture he found rainfall is

more associated with radiation (Reddy, 1987). In line with this, the global

temperature pattern presents a similarity with the Andhra Pradesh Southwest

Monsoon Rainfall cycle. Figure 9d presents the global annual & five-year average

temperature series. On the horizontal axis presented the 56-year cycle (sine curve)

observed in the Southwest Monsoon Rainfall of Andhra Pradesh. The period with

steep raise during around 1910 to around 1945 present below the average rainfall

cycle, then the period around 1945 to around 1975 period of little variation present

the above average rainfall cycle, and the period with steep rise around 1975 to

around 2005 present below the average rainfall cycle. During the third cycle (1973

to 2028) in the dry 28-year cycle the temperatures gone up – during this part

Gangotri Glacier presented higher retreat. A report appeared in media says

that the coming 10-years temperatures will not go up!!! This aspect must be

thoroughly studied at global level, as after increasing the temperature during the

below average rainfall cycle the temperature is not coming back during the above

average rainfall cycle, though it is not showing an increasing or decreasing trend.

Why? This needs an answer.

During 1971 to 2000, West Rajasthan experienced the longest heat wave

spell of duration 16 days and most of the longest spells were experienced in 1972

and during this period the number of sub-divisions affected by cold wave and heat

wave spells presented an increasing trend (Pai & Rajeevan, 2004) but both of

these are confined mainly to their traditional zones only (Reddy & Rao, 1978).

Alwar, on the fringes of the Thar Desert, registered a temperature of 50.6 °C

(123 °F), India’s highest. India’s lowest recorded temperature reading was -45 °C

(-49 °F) in Dras, Ladakh, in eastern Jammu and Kashmir; however, the reading

was taken with non-standard equipment. Further south, readings as low as -

30.6 °C (-23 °F) has been taken in Leh, also in Ladakh. However, temperatures on

the Indian-controlled Siachen Glacier near Bilafond La (5,450 meters (17,881 ft))

and Sia La (5,589 meters (18,337 ft)) have fallen below -55 °C (-67 °F), while

blizzards bring wind speeds in excess of 250 km/h (155 mph), or hurricane-force


winds ranking at 12 (the maximum) on the Beaufort scale. It was those conditions,

not actual military engagements that were responsible for more than 97% of the

roughly 15,000 casualties suffered by India and Pakistan over the course of conflict

in the region. The highest reliable temperature reading was 50.6 °C (123 °F) in

Alwar, Rajasthan in 1955. This mark was also reached at Pachpadra in Rajasthan.

Recently, claims have been made of temperatures touching 55 °C (131 °F) in

Orissa; the IMD, which has questioned the methods used in recording such data,

has met these with some skepticism.

From these presentations it is clear that unusual events in weather & climate

are not associated with a specified period to attribute them to global warming

phenomenon but they are seen at random – like “anything may happen at any

time” similar to earthquakes, forest fires, etc. There is a close relation in observed

fluctuations in different weather parameters such as temperature, cyclones/

hurricanes, precipitation.


Summary

Weather is what we experience daily and climate is the average of such

weather over a long period of time. The climate is highly variable with space and

time. The climate defines the life forms on the Earth.

Natural variations: Climate consists of irregular variations and systematic variations.

The systematic variations are known as cycles. They are of long-term and short-

term fluctuations. The long-term fluctuations are termed as ice ages, mainly

present in temperature. These are derived through proxy data, which vary with

author to author. The short term fluctuations are studied using ground based

observed meteorological data. This aspect is studied primarily with reference to

precipitation data series, as it is the prime factor in the success and failure of

agriculture. Where such fluctuations are present, climatic-normal play a misleading

role. Precipitation data analyzed taking into account the climatic fluctuations, the

results provide better planning tool for successful agriculture (see Reddy, 1993).

However, to make the results more reliable, the observed meteorological data series

must be homogenized at base level through studies to separate the

- Errors due to change in unit of measurements;

- Errors due to changes in place of measurement;

- Errors due to changes in war related disturbances;

- Errors associated with the changes in and around meteorological observatory;

- Now, in majority of developing countries the meteorological stations are in

dilapidated condition due to wars & poverty; etc.

Man-induced changes: With the unabated population growth under changed life

style & technology, weather & climate are affected severely by the changes in

atmospheric composition, land-use & land-cover changes. These changes are known

as trend – both increasing and decreasing.

The observed surface temperature presents an increasing trend with several

ups & downs during the last 100-years. Some claim it is the result of increased

concentrations of anthropogenic greenhouse gases in the atmosphere. The

temperature pattern derived through models using anthropogenic greenhouse gases

as input present smooth non-linear increase and that vary with model to model. It

is clear from these that the increased temperature is not a result of anthropogenic

greenhouse gases concentration in the atmosphere but it is the result of combination

of several factors.

The anthropogenic greenhouse gases observed data is available from the

last five decades only and that too at few unevenly distributed network of stations

over the globe. Prior to this period the data series are constructed through proxy

data. Unlike in observed surface temperature, the carbon dioxide data presents a

smooth non-linear increase.


Urban contamination: The observed surface temperature series are contaminated

by “urban-heat-island effect” – a warming effect. The observed surface temperature

data series represent measurements made mostly in urban-areas, as majority of the

meteorological observatories are located in urban centers. The observed temperature

must also be homogenized at base level like in precipitation. However, the rural

temperatures on the contrary are contaminated by “rural-cold-island effect” – a

cooling effect — with the changed land-use & land-cover.

Land & Sea effect: The land area covers one-third of the globe and oceans by

two-thirds. The observed meteorological data over the oceans is insignificant when

compared to on land meteorological observations network. For the last two decades,

with the help of satellites the temperature data was derived over the land & oceans.

The temperature pattern derived from satellites is far lower than the observed

surface temperature data. Unfortunately, later, the satellite data series were revised

to fit with the observed surface temperature pattern. This created doubt in the

use of satellite data series after seeing the observed surface temperature data

series in Southern Hemisphere with less land area & more ocean area presenting

lower temperatures when compared with the Northern Hemisphere!!!

Ozone depletion: The fact is that both the ozone “creation & destruction” and

“cooling & warming” of temperature are in built in nature. There is an absolute

one-to-one relation in ozone depletion theory and thus, though in the initial stages

there was a stiff opposition from industry, it became easy to replace ozone depleting

substances by non-ozone depleting substances. The reverse trend in ozone depletion

is already evident. The stratospheric cooling effect is more in association with

weather related formation of circum-polar vortex, which is more frequent in the

South Pole zone & less frequent in the North Pole zone. This is reflected in the

ozone depletion patterns at the two poles zones.

Unfortunately, there is no such one-to-one relation in global warming theory,

as there are several process involved. The issue is not moving in the right direction,

as political interests are inter-woven in the issue of global warming, which is

leading no where.

Glaciers retreat & sea level raises: In the glaciers retreat phenomena, some

powerful groups started suppressing the facts. They are not looking glaciers

retreat as a long-term cyclic pattern & part of hydrological cycle as well physical

impacts associated with several phenomena in nature & human injected.

Some scientists noted decreasing temperature in parts of South Pole zone

and Himalayan Glaciers zones.

The observed sea level changes present decreasing trend in certain parts of

the globe; increasing trend certain other parts with majority of the parts presenting

no change. However, the speculators of sea-level rise, using the model based

simulations, flooding the literature with speculations of abnormal rise in sea levels

with wide ranges that are far beyond model error ranges.


We are well aware that physical impact as a result of research, sports,

tourism, pilgrimage activities (that is, human activity), impact of outer space objects

falling, in addition to earthquakes, volcanoes, land-slides, tectonic movements

under the Earth, etc needs careful study in terms of rise in temperatures and or

melting of ice-sheets – sea level rise. This aspect is researched very little!!!

The fact is that during glacial & interglacial periods the increase & decrease

in temperature was responsible for increase & decrease in carbon dioxide

concentrations in the atmosphere. That is, it is an after affect. The present global

warming theory presents the vice-versa process.

Systematic variations & Unusual events: Unusual events in weather & climate are

not associated with a specified period to attribute them to global warming

phenomenon but they are seen at random – like “anything may happen at any

time” similar to earthquakes, forest fires, etc.

The precipitation data from both Southern & Northern Hemispheres present

systematic variations. The observed cycles varied between 66 to 22 years along

with their sub-multiples.

The ups-and-downs observed in global average observed surface temperature

data series present a positive relation with the fluctuations in precipitation. Similar

type of relationship was noted in cyclonic/hurricane activity with the fluctuations

in precipitation. However, the pattern is not uniform all over the globe but present

variable patterns according to zones/regions. That is, averages have no meaning

but must be studied region-wise to get correct picture.

The precipitation & weather present a relationship with the changes in

solar & planetary system. The influence of these changes, change with the prevailing

local synoptic conditions. In some cases, the patterns present reversals. These

must be studied in relation to the prevailing fluctuations at a given region/zone to

get better picture. We must not forget that the sea/ocean tides follow a rhythmic

pattern with phases of the Moon.

In conclusion, as long as our governments sub-serve the interests of Western

Multinational Companies and their propaganda agents, we achieve little in this

direction. They put foot in the energy projects & major irrigation projects to

obstruct to get the fruits of development by rural poor but they are going ahead

un-hindered with the chemical inputs in agriculture under heavy subsidies as usual

to benefit MNCs. This is the root cause of all ills in the society in developing

countries. In this bandwagon entered the genetically modified technology of MNCs

that have severe repercussions on ecology & agriculture of developing countries

like India. Even IPCC is putting its’ stamp of approval on such tendency!!! Majority

of the conclusions in relation to global warming hypothesis are either follow the

proverb “Cat on the Wall” or put forth false logic “wall is white and cow is white,

therefore wall is cow”. Therefore, we must come out from this phobia to understand

the climate change in its’ totality by giving weight to “science” over the “number”

game.


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97. Tyson, P.D., 1978. Rainfall changes over South Africa during the period of

meteorological record. In “Biography of Ecology of South Africa”, W.J.A.

Werger & A.C. van Bruggosa (Eds.), Dr. W. Junk b.v. Publ., The Hague,

pp.53-69.

98. Webb, R.H., McCabe, G. & Hereford, R., (2005). Climatic fluctuations, drought,

and flow in the Colorado River. USGS Circular 1282.

99. Wikipedia on Internet

100. Weatherhead, E.C. and Andersen, S.B., (2006). “The search for signs of

recovery of the ozone layer”. Nature 441:39–45.

101. World Meteorological Organization (WMO), (1966). Climatic Change.

Technical Note No. 79 (Report of a working group of the Commission for

Climatology prepared by J.M>Mitchell, Jr., Chairman; B.Dzerdzeevskii; H.

Flown; W.L.Hofmeyr; H.H.Lamb; K.N.Rao; C.C.Wallen, (WMO-No.195,

TP.100), Geneva, Switzerland, 81p.

Dr. Sazzala Jeevananda Reddy had his M.Sc. (Tech.) in Geophysics and Post-GraduateDiploma in Applied Statistics from the Andhra University – Vishakapatnam, AdvancedTraining in Meteorology & Oceanography from the Training School of India MeteorologicalDepartment – Pune, Ph.D. in Agricultural Meteorology from the “The Australian NationalUniversity”, Canberra. Published around 500 scientific articles. Dr. Reddy was formerlyChief Technical Advisor — WMO/UN and Expert – FAO/UN. Presently serving the causeof Environment. The following are the other books of the author.

• An agroclimatic classification of the semi-arid tropics: An agroclimatic approach forthe transfer of dry-land agricultural technology. Ph.D. Thesis, The Australian NationalUniversity, Canberra, Australia, (1985), 260p.

• Agroclimate of Mozambique: As relevant to dry-land agriculture. Comunicacao No.47, Serie Terra e Agua, INIA, Maputo, Mozambique, (1986), 70p.

• Agroclimatic/Agrometeorological Techniques: As applicable to dry-land agriculturein developing countries. JCT, Hyderabad, A.P., India, (1993), 205p – Book Reviewappeared in Agric. For. Meteorol., 67:325-327 [1994].

• Vastu: A Practical Guide (in English) & Vastuvyamoham: Bramalu-Vastavalu (in Telugu).JCT, Hyderabad, A.P., India, (1997), 106/140p – Book Review appeared in The Hinduand several other dailies.

• Andhra Pradesh Agriculture: Scenario of the last four decades. JCT, Hyderabad,A.P., India, (2000), 104p.

• The concept of prophesying: Myths & Realities. JCT, Hyderabad, A. P., India, (2000),100p.

• Dry-land agriculture of India: An agroclimatological and agrometeorologicalperspective. BS Publications, Hyderabad, A.P., India, (2002), 429p.

• Advanced Technologies in Meteorology. Edited by R. K. Gupta & S. Jeevananda Reddy,Tata McGraw-Hill Publ. Comp. Ltd., New Delhi, India, (1999), 549p.

• Environment and People. JCT, Hyderabad, A. P., India, (2006), 360p.

• Agriculture & Environment. JCT, Hyderabad, A.P., India, (2007), 112p.

About the Author

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