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Greenhouse Effect and Thinning of
the Ozone Layer
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The Greenhouse Effect
Energy from the sun reaches the Earth throughradiation. Some of this radiation is absorbed by theearth to warm the surfaces of sea and land.
As the earth is warmed, heat in the form of infrared
radiation is radiated back into space However much of this radiation is prevented from
escaping into space by greenhouse gases such ascarbon dioxide (CO2) methane (CH4), nitrous oxide
(N2O) and chlorofluorocarbons (CFCs) As a result the infrared radiation is radiated back to
the earths surface, warming the Earth further.
http://environment.nationalgeographic.com/environment/global-warming/gw-overview-interactive/
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This phenomenon is known as the greenhouse
effect. It is similar to a greenhouse used infarming in countries which experience
temperate climates. The glass of a greenhouse
allows light to enter but retards the loss ofheat. The heat is used to keep the soil and air
warm in the greenhouse.
An increase in greenhouse gases is caused by
human activities, mainly
and .
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Generally Suns Rays the Earth
heat
Heat by
greenhouse gases Temperature
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Effect of global warming Melting of polar ice and glaciers causing a rise in sea
level
Floods in low-lying countries Change in wind directions and weather patterns
Increase of droughts
Decline in the yield of crops due to dry and infertilesoil
Spread of pests and disease-carrying vectors to newareas increases the outbreak of diseases
Intense rains in some regions
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Step to reduce global warming Reduce the burning of fossil fuels
Reduce deforestation
Reduce or stop open burning
Practice replanting of trees
Develop other sources of energy such as solar,wind and geothermal energy
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Thinning of the Ozone Layer
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Ozone layer is present in the stratosphere
which approximately 12 - 25 kilometers abovethe Earth;s surface.
This ozone layer shields the earth from the
harmful effects of ultraviolet (UV) radiation. High concentrations of ozone (O3) in the
ozone layer can absorb large quantities of
ultraviolet radiation
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Ozone, although a form of oxygen, once depleted willnot be replenished naturally.
The main cause ozone depletion is the increasinglevel of chlorofluorocarbons (CFCs) in theatmosphere.
The use of CFCs as coolants in air conditioners andrefrigerators, as propellants in aerosol cans, as solventin the electronics industry and as foaming agents inthe making of polystyrene boxes has released largeamounts of CFCs into the atmosphere
CFCs are unreactive and can remain unchanged forover 100 years
UV radiation breaks down CFCs. Releasing chlorineradicals which destroy ozone in a chain reaction
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Exposure to UV radiation effects Human health
- Skin cancer or melanoma
- Eye damage such as cataract
- Lowering of bodys immune system
Plants
- damage of leaf cells and chlorophyll, reducing photosynthesis
- Decrease in nutrient content and crop yields
- Killing phytoplanktons
The Environment
- Increase in surrounding temperature
- Change in wind directions
- Climatic changes
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