- Different types of gases like carbon dioxide, chlorofluorocarbon, methane, oxides of nitrogen, water vapor etc. is present in the troposphere of the atmosphere.
- These gases cover the earth’s surface making dense canopy similar to the glass frame of an artificial green house.
- The dense canopy of different gases allows the solar radiations to enter the earth surface but doesn’t allow it to escape out after reflection.
- As a result, these solar radiations are absorbed in the atmosphere with increasing temperature of the earth.
- The phenomenon of increasing the temperature of the earth as in artificial greenhouse is called green house effect.
- The gases which are responsible for the greenhouse effect are called greenhouse gases.
- Environmental scientists estimated that the green house effect of carbon dioxide was 57%, chlorofluorocarbon was 25%, methane was 12% and that of the oxides of nitrogen was 6%.
- The temperature of the earth is increasing gradually due to greenhouse effect leading to global warming.
- A large mass of ice in the polar caps melts due to global warming which increases the level of the sea.
- It affects the lives of people in coastal areas. Similarly, the temperature of higher regions is increasing more as compared to the lower regions due to the drying of the water resources and decrease in the amount of ice in the Himalayan regions.
Sources of green house gases:
- Green house gases are released from different human activities as well as some natural processes. Some of them are:
- Carbon dioxide gas: It is produced by burning of fossil fuels like coal, petroleum products, natural gases etc.
- Methane gas: It is produced from the decomposition of domestic wastes and sewage.
- Chlorofluorocarbons: They are released from refrigerators, air conditioners, aerosol spray cans etc.
- Water vapor: It is released from the oxidation of organic compounds as well as vaporization of water from water resources.
Importance of green house effect:
- If there were no green house gases in the atmosphere, all the solar radiations entering the earth surface would escape into the space.
- As a result, heat would not be stored on earth and consequently, the temperature of the earth would be less by around 390C than today’s temperature.
- Ice would cover the earth and there would not be any organism on earth
Adverse effects of greenhouse gases:
- Due to various human activities, the concentration of greenhouse gases is increasing day by day.
- It increases the temperature of earth whose adverse effects are as follows:
- Effects on animals:
- It helps spread different types of diseases like malaria, filariasis, cholera, and diarrhea etc due to rise in temperature.
- It helps increase the number of vectors like insects transmitting diseases.
- Effects on plants:
- It affects water cycle, soil moisture and soil composition. As a result, there is a change in cultivation and harvesting periods of crops.
- Due to the effect of global warming, tropical plants are seen at the temperate region.
- It also affects breeding, growth and development of disease causing insects.
- Effects on climate:
- It increases the temperature of earth.
- It brings about the melting of ice in the Polar Regions, which increases the sea level due to which the low land coastal areas may sink and go underwater.
- It also changes the pattern of rainfall and weather conditions.
- Effects on animals:
Ways of controlling greenhouse effect:
- By decreasing the rate of deforestation and increasing afforestation.
- Limited use of fossil fuels like petrol, diesel, kerosene, coal etc.
- Reduction in the production and use of CFCs.
- Alternative sources of energy like solar energy, wind energy, biogas etc. should be preferred over fossil fuels.