ect 11+12 chapt 4 : human populations and natural resources dr. mohammed ajjour university of...

ECT 11+12 Chapt 4 : Human Populations and Natural Resources

Dr. Mohammed Ajjour University Of Palestine

2009,

HISTORY OF P0PULATION GROWTH HOW FAR CAN EARTH ABSORB MORE POEPLE. IMPACTS ON NATURAL RESOURCES , WELFARE AND

GIGNITY OF HUMAN. WHAT IS THE RIGHT WAY TO MINIMISE IMPACTS

University Of Palestine 2009, Dr. Mohammed Ajjour

For most of human history, humans have not been very numerous compared to other species.

- It took all of human history to reach 1billion.

- 150 years to reach 3 billion.- 12 years to go from 5 to 6 billion.- Human population tripled during the

twentieth century

Human Population History

Growth Rates Models Typical

exponential Growth Curve

Unhindered growth, of course, requires unlimited nutrient supply and an unchanging environment. University Of Palestine 2009, Dr. Mohammed Ajjour

Exponential Growth Growth as a percentage

of the whole. If a country's population begins with 1 million and grows at a steady 3 % annually, it will add 30,000 persons the first year, almost 31,000 the second year, and 40,000 by the 10th year. Exponential growth is graphed as a J curve.


Chapter 1

Logistic Growth - Growth slows as the population approaches carrying capacity

Carrying Capacity - Number of individuals that can be indefinitely supported in a given area.

There are no easy answers to the questions: “How many people can the earth support?”, and “At what level of well-being?”. University Of Palestine 2009, Dr. Mohammed Ajjour

Can More People be Beneficial ?- More people mean larger markets, more workers , and

increased efficiency due to mass productions.- Greater numbers also provide more intelligence and

enterprise to overcome problems.- Technological optimists argue that Malthus was wrong in

his predictions because he failed to account for scientific progress.

- - Current burst of growth was stimulated by the scientific and industrial revolutions University Of Palestine 2009, Dr. Mohammed Ajjour

Population-Age Pyramids

Different counties with different population development trends


Populations can not grow without limitations. growth of Human population depends on social, economic , religious, cultural and geobiological factors. Regarding natural resources, their impacts depend on :

Availability in enough amounts ; Costs of exploitation, transport and treatment ; competition with other similar resources.Possibility and costs of recycling.To achieve wise use of resources, there are many choices and

better ways to do things. Better means for better actions with less effort to increase the carrying capacity of the earthUniversity Of Palestine 2009, Dr. Mohammed Ajjour

What can be done ?

Natural resources and Environment

Defintion : useful substances or materials taken from nature and are tradable locally and internationally ( minerals, rocks , fuel, surface and ground water ……..) .

Renewable R: can be renewed or reproduced within Life span of human life( ground water, trees.. Living res. Like fish). Nonrenewable R are those which require millions of year to renew ( Fossil fuel… )

Sustainability of R : Careful use of R without damaging the living environment or affecting their availability to future Generations :

How to sustain Renewable R. ? : balanced use with rate of regeneration

How to sustain nonre R.?: wise consumption , recycling , use alternative rR (wind energy instead of fuel )


Dependency on resources Our live depends completely on resources from

nature( examples..) Use of Res. Is increasing, and parallel, technologies

to develop new R will continue . Carrying capacity of earth is large but not unlimited.

Threat is not expected to come from ending of supply as long as we develop our means to use these R. and to search for alternative. Sustainability of R. is only possible by controlled population growth


Energy as a Resource Major Energy Sources in Nature : Sun, Waves , and

earth


Fossil fuels, such as oil, natural gas, and coal, are the most readily available energy sources . Concerns about environmental impacts, reliance on foreign supplies, and depletion of reserves have led to calls for increased research and development of

alternative sources . Alternative sources, such as wind, solar, and water energy, have been used in one form or another for many centuries but require further development before they are cost-competitive. Coal, oil and gas are called "fossil fuels" because they have been formed from the organic remains of prehistoric plants and animals

Fossil Energy Resources they provide around 66% of the world's electrical power, and

95% of the world's total energy demands (including heating, transport, electricity generation and other uses).

Liquid Hydrocarbons (oil ) : are formed from the remains of plankton and bacteria and other forms of live under the oceans. They are produced either as petrol or Natural Gas.

Solid Hydrocarbons ( Coal ) represent about 90 % of total reserves of fossil fuel in earth .


Fossil Energy Resources Crude oil (called "petroleum") is easier to get out of the ground than coal, as it

can flow along pipes. This also makes it cheaper to transport. and it provides about 40% of our energy.

Natural gas provides around 20% of the world's consumption of energy, and as well as being burnt in power stations, is used by people to heat their homes.It is easy to transport along pipes, and gas power stations produce comparatively little pollution

Coal provides around 28% of our energy, Burning coal produces sulphur dioxide, an gas that contributes to the formation of acid rain when dissolved in rainwater.


Fossil Energy Resources Environmental Concerns when using fossil energy

sources CO2, NO gases production ( greenhouse effect ,global

heating, ozone ). Production of sulphur gases (Acid rain ) . Oil spells , surface and ground water pollution. Landscape distortions ( surface mining ) ,Smell and

explosions ( deep mining ). Impacts on living organisms ( human ,Sea and Oceans life)


Alternative energy resources Nuclear energy :Nuclear power produces around 11%

of the world's energy needs .The reactor uses Uranium as fuel, and the heat is generated by nuclear fission. Neutrons smash into the nucleus of the uranium atoms, which split roughly in half and release energy in the form of heat.


Nuclear energy Advantages : Does not produce smoke or carbon dioxide, so it does not contribute to the

greenhouse effect. Produces huge amounts of energy from small amounts of fuel. Nuclear power costs about the same as coal, so it's not expensive to make. Produces small amounts of waste. Nuclear power is reliable.


Nuclear energy Disadvantages :

Possibility of nuclear emissions :If it does go wrong, a nuclear accident can be a major disaster and People are increasingly concerned about this .

Although not much waste is produced, it is very, very dangerous. It must be sealed up and buried for many years to allow the radioactivity to die away.

Nuclear power is reliable, but a lot of money has to be spent on safety –


Solar Energy Sun was used for drying clothes and food for thousands of

years, but only recently have we been able to use it for generating power.

photovoltaic" or "photoelectric" cells convert light directly into electricity. In a sunny climate, they produce enough power to run a 100W light bulb from just one square meter of solar panel. These days many of our own calculators are powered by solar cells. water heating: heat from the Sun is used to heat water in glass panels on your roof


Solar Energy Solar cells provide the energy to run satellites that orbit the Earth

(satellite TV, telephones, navigation, weather forecasting, the internet..)

Advantages : Solar energy is free - it needs no fuel and produces no waste or

pollution. In sunny countries , solar power can be used where there is no easy

way to get electricity to a remote place.


Solar Energy Disadvantages Doesn't work at night.

Very expensive to build solar power stations.

Can be unreliable unless you're in a very sunny climate..


Wind energy . Babylonians and Chinese were using

wind power to pump water for irrigating crops 4,000 years ago .

Wind power was used in the Middle Ages to grind corn, in so called "windmill“ .

Energy in the wind can be gained by building a tall tower, with a large propeller on the top. KWe tend to build many towers together, to make a "wind farm" and produce more electricity.


Wind energy The more towers, the more wind, and the larger the propellers, the more

electricity we can make. It's only worth building wind farms in places that have strong, steady winds.

MAdvantages Wind is free, wind farms need no fuel. Produces no waste or greenhouse gases The land beneath can usually still be used for farming. Wind farms can be tourist attractions. A good method of supplying energy to remote areas.


Wind energy Disadvantages The wind is not always predictable - some days have no wind. Suitable areas for wind farms are often near the coast, where land is

expensive. Some people feel that covering the landscape with these towers is unsightly. High costs of investment . Can kill birds - migrating flocks tend to like strong winds. Can affect television reception if you live nearby.


hydro-electric power Dams are built to trap water of rivers ,

usually in a valley where there is an existing lake. Water is allowed to flow through tunnels in the dam, to turn turbines and thus drive generators

. Although power stations built are not durable , this form of energy is the cheapest and cleanest of all alternative sources


Biomass - energy Wood was once our main fuel. Wood still provides a small percentage of

the energy we use, but its importance is dwindling . Sugar cane juice can be fermented to make alcohol, which can be burned to generate power in the same way as coal. Alternatively, the cane can be crushed and the pulp (called "bagasse") can be burned, to make steam to drive turbines. Other solid wastes, (rubbish, animal manure, woodchips, seaweed, corn stalks and other wastes ) can be burned to provide heat, or used to make steam for a power station. "Bioconversion" uses plant and animal wastes to produce fuels such as methanol, natural gas, and oil.


Biomass - energy Advantages The fuel tends to be cheap. It makes sense to use waste materials where we can. Less demand on the Earth's resources Disadvantages Collecting the waste in sufficient quantities can be difficult. We burn the fuel, so it makes greenhouse gases. Some waste materials are not available all year round.University Of Palestine 2009, Dr. Mohammed Ajjour

Geothermal Energy The centre of the Earth is around 6000 degrees

Celsius - hot enough to melt rock. Even a few kilometers down, the temperature can be over 250 degrees Celsius. In general, the temperature rises one degree Celsius for every 36 meters you go down. In volcanic areas, molten rock can be very close to the surface.

Geothermal energy has been used for thousands of years in some countries for cooking and heating.


Geothermal Energy Hot rocks underground heat water to produce steam.

We drill holes down to the hot region, steam comes up, is purified and used to drive turbines, which drive electric generators. There may be natural "groundwater" in the hot rocks anyway, or we may need to drill more holes and pump water down to them. Geothermal energy does not produce any pollution, and does not contribute to the greenhouse effect.

.University Of Palestine 2009, Dr. Mohammed Ajjour

Soil as a resource Soil is the upper layer of some parts of solid parts of earth. It

is the result of weathering of the rocky crust and growth of plants , composed of broken rock materials intermixed with fine parts of organic matter and water . It contains minerals and air which allow plants to emerge and to grow . weathering is the processes occurring naturally or by action of man leading to fragmentation of stones and rocks and formation of soil. These processes cause some physical, and chemical changes in structure and properties of rocks which in turn leads to the formation of different soils. We distinguish between :University Of Palestine 2009, Dr. Mohammed Ajjour

Soil as a resource Mechanical W. : fragmentation of rocks to smaller parts due

to changes in pressure and temperatures without changing soil properties. This process leads to infiltration of water deeper in soil and break of rocks when water freeze .and Chemical W .: chemical reactions ( like hydrolysis, dissolution, oxidation … ) which cause further fragmentation and changes in soil reactions and properties. And Biological W. : living parts ( roots , flora , fauna ) may cause mechanical or chemical changes. Factors affecting weathering and soil formation are : climate, composition of rocks , time and topography. University Of Palestine 2009, Dr. Mohammed Ajjour

Soil as a resource Soil itself is very complex. It would be very wrong to think

of soils as just a collection of fine mineral particles. Soil also contains air, water, dead organic matter, and various types of living organisms . The formation of a soil is influenced by organisms, climate, topography, parent material, and time.


Soil as a resource Most soils have a distinct profile or

sequence of horizontal layers. Generally, these horizons result from the processes of chemical weathering, eluviation, illuviation, and organic decomposition. Up to five layers can be present in a typical soil: O, A, B, C, and R horizons


Soil as a resource The O horizon is the topmost layer of most soils. It is composed mainly of plant litter

and humus. A horizon. This layer is composed primarily of mineral particles in which humus and

other organic materials are mixed. The A horizon is commonly differentiated into a darker upper horizon or organic accumulation, and a lower horizon showing loss of material by eluviation.

The B horizon is a mineral soil layer which is strongly influenced by illuviation. Consequently, this layer receives material eluviated from the A horizon.

The C horizon is composed of weathered parent material. The texture of this material can be quite variable . The C horizon has also not been significantly influenced by the pedogenic processes, translocation, and/or organic modification.

The final layer is called the R horizon. This soil layer simply consists of unweathered bedrock.


Soil as a resource Soil texture :is a soil property used

to describe the relative proportion of different grain sizes of mineral particles in a soil. Particles are grouped according to their size into clay, silt, and sand. The soil texture triangle is a diagram often used to figure out soil textures.

Soil conservation University Of Palestine 2009, Dr. Mohammed Ajjour

Soil as a resource Soil Denudation is a term that indicates the process of

removal of material, through means of erosion and weathering, which leads to a reduction of elevation and changes in landforms and landscapes. Processes, including the action of water, ice, and wind, involve denudation. At present the most significant processes leading to denudation include deforestation , overgrazing and certain forms of intensive farming . Factors affecting Denudation include: Surface geography ,Properties of Earth material , Climate , Activities of man, animals and vegetation

.University Of Palestine 2009, Dr. Mohammed Ajjour

Soil as a resource Soil degradation When plants are cleared from a site, soil is

exposed to sunlight and the eroding effects of wind and water. Soil aeration and the rate of weathering increases .The proportion of organic matter in the soil gradually decreases, unless new land use provides some replacement. TYPES OF SOIL DEGRADATION :

- Loss of soil fertility , - Erosion

- Salinity - Soil compaction

- Soil acidification - Build up of dangerous chemicals


Soil as a resource Soil conservation is a set of strategies for prevention of soil

being eroded from the earth’s surface or becoming chemically altered by overuse, salinization, acidification, or other chemical soil contamination. The principal approaches these strategies take are: choice of vegetative cover , erosion prevention ,salinity management , acidity control, encouraging health of beneficial soil organisms , prevention and remediation of soil contamination . other ways are; no till farming , contour plowing, crop rotation ,the use of natural and man-made fertilizer , resting the land (Shmita)


ect 11+12 chapt 4 : human populations and natural resources dr. mohammed ajjour university of...

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