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Greenhouse Effect and Major Greenhouse Gases
The earth’s temperature has been rising during the recent past. This is due to the greenhouse effect. This term is derived from a phenomenon that occurs in a greenhouse. In order to understand the reason behind earth’s increasing temperature, it is essential to know what a greenhouse is and how does it works.
A greenhouse is basically a glass chamber in which plants are grown especially during winter season. When sunlight passes through the glass it gets absorbed inside but the greenhouse does not allow the radiations to escape. Thus, the temperature inside becomes warm enough to support plant growth.
The same phenomenon happens on the earth surface. When sunlight reaches the earth, some of it is reflected back by the atmosphere and some is absorbed by air particles. Rest of the sunlight reaches earth heating it. The earth’s surface now heats up and emits this heat in the form of infrared radiations. But major portion of this radiation is absorbed by atmospheric gases which does not allow this heat to escape into space and radiates it back to the earth, heating it up once again. This is called greenhouse effect.
In simple words, greenhouse effect is that property of the atmosphere which allows solar radiation to reach the earth easily but does allow terrestrial radiation to escape from earth easily.
Greenhouse effect is a natural phenomenon which is essential for sustenance of life on earth. It blankets the earth’s atmosphere and warms it, maintaining a suitable temperature for humans to survive but recent industrialisation and urbanisation has increased the emission of greenhouse gases which has exacerbated the greenhouse effect further leading to global warming.
The gases which are responsible for greenhouse effect are called greenhouse gases. These gases absorb the infrared radiations emitting from earth and does not allow it to escape. Increase in the level of these gases has led to considerable heating of earth.
Major greenhouse gases include the following:
Carbon dioxide: It is one of the major greenhouse gases. It is released into the atmosphere by respiration, burning of fossil fuels and organic waste and deforestation. It is also emitted during volcanic eruptions. Increased deforestation and fossil fuel burning has increased its emission. Carbon dioxide is one of the major contributor of global warming.
Methane: It is produced during the burning of vegetation and fossil fuels. A large amount of methane is also released from rotting garbage dumps, paddy fields and coal mines.
Nitrous oxide: Burning of fossil fuels, wood and crop residue releases nitrous oxide in the air.
Hydrofluorocarbons(HFCs): HFCs are man-made industrial chemicals used in air conditioning and refrigeration. They are also used as solvents, insulation foams and aero propellants. They are potent greenhouse gases with long atmospheric lifetimes and high global warming potential.
Water Vapour: It is also responsible for greenhouse effect. Though it is not directly emitted by humans, increasing evaporation due to rising temperature has increased the concentration of water vapour in the air.
Ozone: Ground level ozone confined to troposphere contributes to greenhouse effect. It is a secondary pollutant formed during the chemical reaction between nitrous oxide and volatile organic compounds during the presence of sunlight. Stratospheric ozone protects from ultraviolet rays of sun but tropospheric ozone causes headache, chest pain, dryness of the throat, cough and difficulty in breathing. It also leads to cracking of rubber and extensive damage to plant life apart from contributing to global warming.
Coping with the Greenhouse Effect
- Adopting cleaner fuel technologies. Instead of burning, vegetation and crop residue should be used to make bioethanol which is an eco-friendly fuel.
- Adopting non fossil fuel based energy resources like wind energy, solar energy which do not release any harmful gases in the atmosphere.
- Promoting and adopting electric and hybrid vehicles. Also, automobiles should be properly maintained and emission control norms should be adhered to.
- Undertaking afforestation and reducing deforestation. Trees are excellent sources of carbon sequestration and helps in maintaining the temperature of earth.
- Restrictions should be imposed on industries and power plants to not exceed a certain level of fossil fuel emissions. They should be promoted to use alternative technologies which do not harm the environment.
- Devices like fabric filters, electrostatic precipitators, wet scrubbers, etc should be installed in industries to prevent the escape of harmful gases in the air.
- Carbon sequestration ( capturing and storing carbon in natural or man made sinks) could help in reducing the atmospheric and marine accumulation of greenhouse gases.