IGCSE Environmental Management Chapter 3 Hydrosphere Notes

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Chapter 3: Hydrosphere Environmental Management By Niharika Shinde BlackWhiteWise

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Composition of the Air Gas

Percentage Composition (%)

Nitrogen

78

Oxygen

21

Carbon Dioxide

0.04

Argon

0.96 ighelp.blogspot.com

Energy Source • Sunlight is a shortwave radiation • Reflected heat is longwave radiation

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Insolation • Insolation is the amount of solar radiation reaching a given area. • Insolation rate is the highest at the equator and is lowest at the poles

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Atmospheric Pollution – Causes • • • • •

Fossil fuels in power stations Waste from industries Bare soil: is carried by wind resulting in soil erosion CFCs and Halons Deforestation

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Atmospheric Pollution – Effects • • • •

Poor air quality, can affect lungs: Asthama Reduced visibility Acid rain – Due to sulfur dioxide and oxides of nitrogen – Source: Vehicles, power stations, industries – Effects: Crop destruction, forest destruction, soil erosions, trees become less resistant to droughts, leaves fall early, acidity in lake causes death of marine animals ighelp.blogspot.com

Atmospheric Pollution – Effects • Ozone layer Depletion – Cause: CFCs – Source of CFCs: Hair sprays, refrigerants, air conditioning – Increased UV radiation » Skin cancer » Effects humans and animals

– Less transpiration » Less precipitation due to less cloud formation » Droughts, decrease in crop yields and food supply

– Global Warming Increases ighelp.blogspot.com

Green house gases: Carbon dioxide – Source: burning fossil fuels and wood & deforestation Methane – Source: Deforestation and decomposition of waste NOx (oxides of nitrogen) – Source: transport systems, burning of fuels, use of fertilizers ighelp.blogspot.com

Increased Greenhouse effect • Effect of this increased process: – Increase in global temperature – Ice sheets melting – Rise in sea levels – Flooding in low-lying coastal areas – Defenses breached – Populated areas no longer habitable

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Atmospheric Pollution – Solution • Catalytic convertors installed in vehicle exhausts • Using gas instead of petrol and diesel • Adding powdered limestone in lakes • Limestone treatment in chimneys of power stations to convert Sulfur Dioxide into Calcium Sulfate before it leaves the chimney the oxides of nitrogen are reduced by using ammonia ighelp.blogspot.com

Atmospheric Pollution – Solution • Natural gas power stations instead of coal power stations • Alternative energy sources like Hydro-electric power stations • Reduction in use of CFCs • Increased plantation • Reduced burning of fossil fuels ighelp.blogspot.com

Measuring the weather • Air pressure: – Barometer (either mercury or aneroid) • Mercury barometer: mercury level increases and falls with increase and decrease in air pressure • Aneroid: upper surface is sensitive to changes in pressure • Air pressure is measured in millibars or mmHg

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Measuring the weather • Temperature: – Thermometer (either minimum or maximum) • Maximum thermometer consists of mercury and a metal index. The mercury rises and falls with changes in temperature, pushing and leaving behind the metal index in the process. • Minimum thermometer consists of alcohol and metal index. Alcohol expands and contracts with changes in temperature, moving the metal index up and down ighelp.blogspot.com

Measuring the weather • Precipitation: – Rain gauge

• Rain enters the funnel and the measuring cylinder is used to take readings.

• Wind:

– Weathervane – Anemometer

• 3 or 4 cups that rotate and there is a counter.

• Sunshine:

– Sunshine Recorder

• Glass sphere and recording paper with divisions for the time of day ighelp.blogspot.com

Farming systems • Arable

– Only crops are grown

• Pastoral

– Rear animals either for animal by-products or for meat

• Commercial

– Crops and animals are produced to sell

• Subsistence

– Crops and animals are produced to feed the farmers’ own family

• Extensive

– Small yield, large farmland area

• Instensive

– Small area, high yield ighelp.blogspot.com

Farming • Normal cultivation (rainforest) 1. 2. 3. 4. 5.

Small plot is cleared by slash and burn method Crops planted No nutrient added to soil Soil loses fertility over the years Plot is abandoned and another plot is cleared and used 6. Small plants take over abandoned plot ighelp.blogspot.com

Farming • Wet rice cultivation (Asia) – Monsoon brings heavy rains – Flat flood plains and delta – Silt soils – fertile, deep, easy to work with

Techniques to Increase Yield - Farming • • • • •

Irrigation from rivers and lakes through canals Inorganic Fertilizers and Pesticides Tractors High yielding varieties of seeds (HYV) Plants with certain resistance used (e.g. disease resistant) ighelp.blogspot.com

Adverse effects of modern practices • Overuse of fertilizers & pesticides leads to eutrophication and nitrates accumulate in drinking water • Eutrophication: excessive richness of nutrients in a lake or other body of water, frequently due to run-off from the land, which causes a dense growth of plant life.

• Irrigation causes salinization • Salinization: the process of increasing the salt content in the soil is known as salinization

• Overcultivation and overgrazing results in soil erosion and desertification ighelp.blogspot.com

Solutions • Instead of irrigation surface channels, use sprinklers and trickle drip • Use organic fertilizers • Mixing crops • Use natural predators instead of pesticides

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Climatic Hazards • Tropical cyclones :

– storms formed when sea water is at its hottest, air above sea surface heats up and warm moist air starts to rise (show diagram), low pressure develops deeply in the centre and sucks up more air from the surface, huge circular swirl of cloud forms, around which wind speed increases, rainfall from clouds.

• Impact: – – – – – – –

Immediate loss of life Destroy buildings Flooding due to rains Economic losses Infrastructure damaged Disruption of water supplied – diseases Farming economy ruined

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