Page 3 - GREENHOUSE EFFECT AND GLOBAL WARMING

1. Carbon dioxide- It is mainly produced by respiration in living organisms
and burning of fuels. Over the past few years, due to various human

activities and increase in population, the amount of carbon dioxide
present in air has increased a lot. This has definitely disturbed the

balance of oxygen and carbon dioxide in the air.
2. Methane- It is another greenhouse gas released from landfills and

wetlands. Grass-eating animals, while digesting their food, also release
large quantities of methane into the atmosphere. Methane is also

released when manure is produced from animal waste.
3. Water vapour in the air comes from the evaporation of water from

water bodies. It accounts for 35-37% of the greenhouse effect.
4. Ozone present in the stratosphere is also a greenhouse gas.

GLOBAL WARMING

 A gradual increase in the average temperature of the earth’s lower
atmosphere due to increase in the concentration of greenhouse gases is

called global warming.
 In recent years, the amount of greenhouse gases in the air has increased

due to pollution. This has resulted in more heat being trapped in the
atmosphere leading to an overall rise in the surface temperature of the

earth. This is called global warming.
 As a result of global warming, the average temperature of the earth has
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increased by 1 F in the last 100 years. If this continues, it will cause melting
of polar ice caps. Hence, water levels in the oceans will rise and large areas

of land will get submerged.