Basic Climate Change

These lectures are adapted from

USAID LEAF’s Regional Climate Change Curriculum

Nguyen Le Ai Vinh, PhD.

Biology Faculty, Vinh University

Nghe An, 2015 106/03/2015

Basic Climate Change

Chapter 1.

Introduction to Climate Science and Introduction to Climate Science and

Climate Change

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Learning objectives

At the end of this session, learners will be able to:

• Differentiate between climate change and climate

impacts

• Explain how climate impacts are discerned

3

• Explain how climate impacts are discerned

• Analyze how impacts of climate change combine

with other impacts to people and the environment

• Explain what impact pathways are and how to

discern and evaluate them

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Outline

1. Weather and Climate2. Climate System3. Climate Variation3. Climate Variation4. Climate Change

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List the following things about climate science and

climate change:

3 things you know about the

topic

2 things you want to

learn/don’t know

1 question you want to ask

Pair yourself to the one sitting on your right hand site and discuss

your answers.06/03/2015 5

1. Weather and Climate

a) Why study climate?

– Reasons

– Case study: Biomes of the world

b) Weather

– Definition– Definition

– Characteristics

– Meteorology

c) Climate

– Definition

– Characteristics

– Climatology

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Some reasons:

1. Climate determines the type and location of

human-managed ecosystems, such as

agricultural farmlands.

2. Climate affects the weathering of rock, the type 2. Climate affects the weathering of rock, the type

of soil that forms, and the rate of soil formation.

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3. Helps to determine the quantity and quality of

water available for human use.

4. Determines the severity of droughts, storms, and

floods.

Largely determines the nature and locations of 5. Largely determines the nature and locations of

biomes -major terrestrial ecosystems, defined

based on their plant communities.

6. ….

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Place Average Temperature oCAnnual Precipitation

(cm)Biome

La Selva, Costa Rica 22.1 403

Marietta, Ohio 12 105

Pasadena California 18.2 51.8Ferron, Utah 8.8 20.9Tucson, Arizona 21.1 21.9

Santa Rosa, Costa Rica 26 165

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Santa Rosa, Costa Rica 26 165

Brazzaville, Congo 25 137

Lambarene, Gabon 25.7 195

Amauulu, Hawaii 20 410Toolik Lake, Alaska -8.8 18Beijing, China 11.8 63.5

Seoul, South Korea 11.2 137

Archbold Biological Station

29.1 131

Everglades National Park (Flamingo)

28.1 159

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Place Average Temperature oCAnnual Precipitation

(cm)Biome

La Selva, Costa Rica 22.1 403 Tropical Rain Forest

Marietta, Ohio 12 105Temperate Deciduous Forest

Pasadena California 18.2 51.8 SavannaFerron, Utah 8.8 20.9 DesertTucson, Arizona 21.1 21.9 Subtropical Desert

Santa Rosa, Costa Rica 26 165 Tropical Seasonal Forest

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Santa Rosa, Costa Rica 26 165 Tropical Seasonal Forest

Brazzaville, Congo 25 137 Tropical Seasonal Forest

Lambarene, Gabon 25.7 195 Tropical Seasonal Forest

Amauulu, Hawaii 20 410 Tropical Rain ForestToolik Lake, Alaska -8.8 18 TundraBeijing, China 11.8 63.5 Temperate Grassland

Seoul, South Korea 11.2 137Temperate Deciduous Forest

Archbold Biological Station

29.1 131 Tropical Seasonal Forest*

Everglades National Park (Flamingo)

28.1 159 Tropical Seasonal Forest*

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What is Weather?

What is Climate?

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Definition:

� The actual state of the atmosphere in a period of

several hours up to a few days (in a given place)

(Gramelsberger & Feichter, 2011).

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� Temperature

� Wind

� Clouds

� Precipitation/

Humidity/RainHumidity/Rain

� What we are

feeling in present

time and a given

place →

METEOROLOGY

(The science of

weather).06/03/2015 15

1. The field of atmospheric science which is most well-

known and of practical importance to the general

public is meteorology, the study of weather.

2. Meteorology is usually concerned only with the Meteorology is usually concerned only with the

lowest region of the atmosphere, the troposphere.

3. Weather is influenced not only by vertical, diurnal,

and seasonal variations of atmospheric density and

temperature, and of solar heating, but also by

horizontal variations over Earth’s surface.06/03/2015 16

4. Atmospheric winds and circulation are influenced

by Earth’s rotation, and by surface conditions (i.e.

whether land or sea, topography, and surface

temperature).temperature).

5. The advent of weather-monitoring satellites, and of

supercomputers, have greatly facilitated the science

and application of meteorology in recent years.

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Definitions

� A statistical description in terms of the mean and

variability of relevant quantities over a period

ranging from months to thousands or millions of ranging from months to thousands or millions of

years (IPCC).

� The classical period is 30 years, which are most often

surface variables such as temperature, precipitation,

and wind. Climate in a wider sense is the state,

including a statistical description, of the climate

system (World Meteorological Organization, WMO).

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� Climate element: It is any physical quantity (e.g.,

temperature, rain, iceberg frequency, hurricane

track…)

� Climate element exhibits time and space variations.

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Climate element exhibits time and space variations.

� Climate is defined to include all the statistical

properties of the system consisting of the

atmosphere, land surfaces and oceans (climate

system)

� The climate is always changing, always has changed.

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1,000,000 year time scales

Plate tectonics

100,000 year time scales

Orbital variations and glacial

periodsperiods

100-10 year time scales

Events like the Little Ice Age and

Medieval Warm Period

10-5 year time scales

El Niño – La Niña cycles

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500 mya 400 mya

300 mya 200 mya

Ice sheets can only grow when continents are at the poles.06/03/2015 21

A B

C

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EARTHEARTH

The Earth’s orbit is almost

a perfect circle with slight

variations every 100,000

and 400,000 years.

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A B

C

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� The output of energy

from the sun has been

monitored by satellites

for thirty years and has for thirty years and has

NOT increased during

this period of rapid

global warming.

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2806/03/2015

Chance are better than 50%

El Nino conditions will

develop this year (2014-

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develop this year (2014-

2015).

NOAA's Climate Prediction Center

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2. Climate System

a) Components of the Climate System

b) Interactions among the components

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Five major

components:

1. The atmosphere

2. The hydrosphere

Air

WaterLand

Ice

2. The hydrosphere

3. The cryosphere

4. The lithosphere/

The land surface

5. Biosphere

Life

Land

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� It is the most unstable and rapidly changing part of the system.

� It is composed mainly of nitrogen (N2, 78.1% volume mixing ratio), oxygen (O2, 20.9% volume mixing ratio, and

Air

(O2, 20.9% volume mixing ratio, and argon (Ar, 0.93% volume mixing ratio).

� Green house gases such as carbon dioxide (CO2), methane (CH4), nitrousoxide (N2O) and ozone (O3),

� It also contains solid and liquid particles (aerosols) and clouds.

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� It is the component comprising all liquid surface and subterranean water, both fresh water and saline water.

� The oceans cover approximately 70% of the Earth’s surface.They store and transport a large amount

Water

� They store and transport a large amount of energy and dissolve and store great quantities of carbon dioxide.

� They function as a regulator of the Earth’s climate and as a source of natural climate variability, in particular on the longer time-scales.06/03/2015 34

� The cryosphere includes the ice sheets of Greenland and Antarctica, continental glaciers and snow fields, sea ice and permafrost.

� It derives its importance to the climate system from its high reflectivity (albedo) for solar

Ice

from its high reflectivity (albedo) for solar radiation, its low thermal conductivity, its large thermal inertia and, especially, its critical role in driving deep ocean water circulation.

� Because the ice sheets store a large amount of water, variations in their volume are a potential source of sea level variations

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� Vegetation and soils at the land surface control how energy received from the Sun is returned to the atmosphere. Some is returned as long-wave (infrared) radiation, heating the atmosphere as the land surface warms.

� Some serves to evaporate water. Because

Land

� Some serves to evaporate water. Because the evaporation of soil moisture requires energy, soil moisture has a strong influence on the surface temperature.

� The texture of the land surface (its roughness) influences the atmosphere dynamically as winds blow over the land’s surface.

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� The marine and terrestrial biospheres have a

major impact on the atmosphere’s

composition.

� The biota influence the uptake and release of

greenhouse gases.

Life

� Through the photosynthetic , plants store

significant amounts of carbon from carbon

dioxide.

� Other biospheric emissions (volatile organic

compounds - VOC) which may have important

effects on atmospheric chemistry, on aerosol

formation and therefore on Climate.06/03/2015 37

� Many physical, chemical and biological interaction processes occur among the various components of the climate system on a wide range of space and time scales, making the system extremely complex.

� Examples:� The atmosphere and the oceans are strongly coupled and

exchange, among others, water vapour and heat through evaporation.

� Sea ice hinders the exchanges between atmosphere and oceans;

� The biosphere influences the carbon dioxide concentration by photosynthesis and respiration, which in turn is influenced by climate change

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Air Ice

Water

Life

Land

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3. Climate Variation

• Natural Forcing of the Climate System

• The natural variability of the climate

• Dynamics of the Earth

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a) The Sun and the global energy balance

b) The natural greenhouse effect

c) Radiative forcing and forcing variability

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� The ultimate source of energy that drives the climate system is radiation from the Sun. About half of the radiation is in the visible short-wave part of the electromagnetic spectrum. The other half is mostly in the near-infrared part, with some in the ultraviolet part of the spectrum.

� Each square metre of the Earth’s spherical surface outside the atmosphere receives an average throughout the year of 342 Watts of solar radiation, 31% of which is immediately reflected back into space by clouds, by the atmosphere, and by the Earth’s surface. The remaining 235 Wm−2 is partly absorbed by the atmosphere but most (168 Wm−2) warms the Earth’s surface: the land and the ocean.06/03/2015 43

� The Earth’s surface returns the heat to the atmosphere, partly as infrared radiation.

� For a stable climate, a balance is required between incoming solar radiation and the outgoing radiation emitted by the climate system. Therefore the climate system itself by the climate system. Therefore the climate system itself must radiate on average 235 Wm−2 back into space.

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� The atmosphere contains several trace gases which absorb and emit infrared radiation. These so-called greenhouse gases absorb infrared radiation, emitted by the Earth’s surface, the atmosphere and clouds, except in a transparent part of the spectrum called the “atmospheric a transparent part of the spectrum called the “atmospheric window”.

� GHGs trap heat within the atmosphere. This mechanism is called the natural greenhouse effect.

� Clouds also play an important role in the Earth’s energy balance and in particular in the natural greenhouse effect.

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� In an equilibrium climate state the average net

radiation at the top of the atmosphere is zero. A

change in either the solar radiation or the infrared

radiation changes the net radiation. The corresponding

imbalance is called “radiative forcing”.imbalance is called “radiative forcing”.

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� External forcings, such as the solar radiation or the large

amounts of aerosols ejected by volcanic eruption into the

atmosphere, may vary on widely different time-scales, causing

natural variations in the radiative forcing. These variations may

be negative or positive. In either case the climate system must

react to restore the balance. A positive radiative forcing tends react to restore the balance. A positive radiative forcing tends

to warm the surface on average, whereas a negative radiative

forcing tends to cool it. Internal climate processes and

feedbacks may also cause variations in the radiative balance by

their impact on the reflected solar radiation or emitted infrared

radiation, but such variations are not considered part of

radiative forcing.

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� Internally and externally induced climate

variability

� Feedbacks and non-linearities

� Global and hemispheric variability� Global and hemispheric variability

� Regional patterns of climate variability

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IPCC, 3rd AR:

� Climate variability refers to variations in the mean state

and other statistics (such as the occurrence of extremes,

etc.) of the climate on all temporal and spatial scales etc.) of the climate on all temporal and spatial scales

beyond that of individual weather events. Variability may

be due to natural internal processes within the climate

system (internal variability), or to variations in natural or

anthropogenic external forcing (external variability)

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� When variations in the external forcing occur, the response time of the

various components of the climate system is very different. With regard

to the atmosphere, the response time of the troposphere is relatively

short, from days to weeks, whereas the stratosphere comes into

equilibrium on a time-scale of typically a few months. Due to their large

heat capacity, the oceans have a much longer response time, typically heat capacity, the oceans have a much longer response time, typically

decades but up to centuries or millennia. The response time of the

strongly coupled surfacetroposphere system is therefore slow

compared with that of the stratosphere, and is mainly determined by

the oceans. The biosphere may respond fast, e.g. to droughts, but also

very slowly to imposed changes. Therefore the system may respond to

variations in external forcing on a wide range of space- and timescales.

The impact of solar variations on the climate provides an example of

such externally induced climate variations.06/03/2015

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� But even without changes in external forcing, the

climate may vary naturally, because, in a system of

components with very different response times and

non-linear interactions, the components are never in

equilibrium and are constantly varying. An example of equilibrium and are constantly varying. An example of

such internal climate variation is the El Niño-Southern

Oscillation (ENSO), resulting from the interaction

between atmosphere and ocean in the tropical Pacific.

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� A process is called a feedback when the result of the process

affects its origin thereby intensifying (positive feedback) or

reducing (negative feedback) the original effect. An

important example of a positive feedback is the water

vapour feedback in which the amount of water vapour in the

atmosphere increases as the Earth warms. This increase in

turn may amplify the warming because water vapour is a

strong greenhouse gas. A strong and very basic negative

feedback is radiative damping: an increase in temperature

strongly increases the amount of emitted infrared radiation.

This limits and controls the original temperature increase.

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� Many processes and interactions in the climate system

are non-linear. That means that there is no simple

proportional relation between cause and effect. A

complex, non-linear system may display what is

technically called chaotic behaviour. Thistechnically called chaotic behaviour. This

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Let Walk through:

Global Climate System Video

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1. Atmospheric Circulation

2. Ocean Circulation

3. Land Surface Processes

4. Vegetation - Carbon4. Vegetation - Carbon

5. Snow and Ice

6. El Niño

7. La Niña

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a) The Sun and the global energy balance

b) The natural greenhouse effect

c) Radiative forcing and forcing variability

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� What atmospheric circulation?

� What is Coriolis effect?

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1. The atmospheric convection cells play to convey

heat from the warm equatorial region to the cold

polar regions.

2. Warm air rises near the equatorial latitudes. 2. Warm air rises near the equatorial latitudes.

3. When the rising warm air reaches the peak of the

troposphere, it moves toward the poles, and when

the air cools, it flows and becomes dense enough to

sink at latitudes of about 30oN or 30oS.

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4. When this cold air reaches the Earth's surface, it is

moved toward the equator, and it then warms and

rises.

5. Where the air is rising or sinking at the equator, 30o, 5. Where the air is rising or sinking at the equator, 30o,

50o, 60o, and at the poles.

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� Comes from the Earth’s rotation influencing the

direction of the air movement.

� The tendency of a free movement of object to appear to

move to the right in the northern hemisphere and to

the left in the southern hemisphere due to Earth's the left in the southern hemisphere due to Earth's

rotation.

� Air moves horizontally from high to low pressure zones,

forming the major wind belts, including the trade winds,

between the equator and 30oN and 30oS; between 30oN

and 30oN and 50o to 60oN and 50o to 60oS; and the polar

winds.06/03/2015 62

Jet Stream occurs

here

Jet Stream occurs

here

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Video on

Atmospheric Circulation

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1. The oceans play a large part of in determining the

existing climate of the Earth.

2. It seems to have a crucial influence on climate

change due to human activities.

3. Ocean and atmosphere are close interactions and

have a strong system.

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4. Oceans have high capacity to contain heat

compared with the atmosphere driving to gradually

raise temperature in the oceans.

5. Oceans redistribute heat throughout the climate

system through their internal circulation.

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Video on

Ocean Circulation

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Carbon only affects climate when it is in the atmosphere

Gases move through the Earth reservoirs:

� Atmosphere

� Biosphere (living things)� Biosphere (living things)

� Lithosphere (solid earth)

� Hydrosphere (freshwater and oceans)

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Video on

Carbon Cycle

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� The presence or absence of snow and ice affects

warming and cooling over the Earth’s surface,

influencing the Earth’s energy balance.

Changes in snow and ice cover affect freshwater � Changes in snow and ice cover affect freshwater

availability, air temperatures, sea levels, ocean

currents, and storm patterns.

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� A reduction in snow cover and ice causes the Earth’s

surface to absorb more energy from the sun

(decreased albedo), which is a positive feedback,

causing stronger warmingcausing stronger warming

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� What is El Niño?

� El Niño is the prolonged warming in the Pacific

Ocean sea surface temperature compared with

the average value. It is a warming of at least 0.5°C

(0.9°F) averaged over the east-central tropical (0.9°F) averaged over the east-central tropical

Pacific Ocean.

� A pattern of ocean surface temperature in the

Pacific off the coast of South America, which has a

large influence on world climate (Houghton,

2009).

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� The first signs of an El Niño are:

1. Rise in surface pressure over the Indian Ocean,

Indonesia and Australia

2. Fall in air pressure over Tahiti and the rest of the 2. Fall in air pressure over Tahiti and the rest of the

central and eastern Pacific Ocean

3. Trade winds in the south Pacific weaken or head

east.

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� The first signs of an El Niño are:

4. Warm air rises near Peru, causing rain in the

northern Peruvian deserts

5. Warm water spreads from the west Pacific and 5. Warm water spreads from the west Pacific and

the Indian Ocean to the east Pacific. It takes the

rain with it, causing extensive drought in the

western Pacific and rainfall in the normally dry

eastern Pacific.

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El Niño: Warm water

pool approaches South

American coast.

Absence of cold

upwelling increases

warmingwarming

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La Niña: Equatorial

winds gather warm

water pool toward the

west. Cold water

upwells along South

American coastAmerican coast

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� El Niño in general occurs in every 3 to 7 years and

appears around Christmas period.

� Droughts and floods occurring almost all continents

are associated with El Niño.are associated with El Niño.

� ENSO caused by the shift of the atmospheric-oceanic

conditions, due to the way the oceans store and

transport heat.

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SST °C SST °C

El NiñoLa Niña

DroughtFlood

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Video clip on

El Niño and La Niña

https://www.youtube.com/watch?v=7FVZrw7bk1w

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4. Climate Change

• What is Climate Change?• The primary indicators of climate change• Warming of Climate.

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IPCC, 3rd AR:

Climate change: a statistically significant variation in

either the mean state of the climate or in its

variability, persisting for an extended period variability, persisting for an extended period

(typically decades or longer).

Climate change may be due to natural internal

processes or external forcings, or to persistent

anthropogenic changes in the composition of the

atmosphere or in land use .

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UNFCCC, Article 1:

“climate change”: “a change of climate which is

attributed directly or indirectly to human activity

that alters the composition of the global atmosphere that alters the composition of the global atmosphere

and which is in addition to natural climate variability

observed over comparable time periods.”

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IPCC, 3rd AR:

� Climate variability refers to variations in the mean

state and other statistics (such as the occurrence of

extremes, etc.) of the climate on all temporal and extremes, etc.) of the climate on all temporal and

spatial scales beyond that of individual weather

events. Variability may be due to natural internal

processes within the climate system (internal

variability), or to variations in natural or

anthropogenic external forcing (external variability)

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Seven of these indicators would be expected to increase in a warming world and observation show that

they are, in fact, increasing. Three would be expected to decrease and they are, in fact, decreasing.06/03/2015 89

� Increases in global sea and air temperatures

� Widespread melting of snow and ice

� Rising global sea level

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What can/cannot be controlled…

� Solar system?

� Earth system?

� Earth Dynamics?

If something can, how? If cannot, how?

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� Most mountain glaciers are getting smaller.

� Snow cover is retreating earlier in the spring.

� Sea ice in the Arctic is shrinking in all seasons, most

dramatically in summer.

Reductions are in the permafrost, seasonally frozen � Reductions are in the permafrost, seasonally frozen

ground and river and lake ice.

� Important coastal regions of ice sheets on Greenland

and West Antartica, and the glaciers of the Antartic

Peninsular, are thinning and contributing to sea level

rise.06/03/2015 92

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� The change in sea ice in the previous slide:

� Discuss: How does this change affect the heating of

the Earth’s atmosphere?

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Two major causes of global sea level rise:

� Thermal expansion of the oceans (water expands as it

warms)

Loss of land-based ice due to increased melting (glaciers � Loss of land-based ice due to increased melting (glaciers

and continental ice caps)

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Warming of the climate

system evidence:

� Increases in global

average air and average air and

ocean temperature

� Widespread melting

of snow and ice

� Rising global mean

sea level

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� Importance of understanding and studying of climate, its

characteristics,

� Key elements and dynamics to determine climatic

condition,

97

condition,

� Climate system,

� Energy budget,

� El Niño and La Niña,

� Climate change and global warming.

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� What was useful?

� What is missing?

� How did you, or would you, modify the materials to make

them better fit your instructional context? them better fit your instructional context?

� Please share your experience and modifications here:

climatecurriculum@googlegroups.com

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