The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface, energy is transferred to the surface and the lower atmosphere.There are two meanings of the term “greenhouse effect”. There is a “natural” greenhouse effect that keeps the Earth’s climate warm and habitable. There is also the “man-made” greenhouse effect, which is the enhancement of Earth’s natural greenhouse effect by the addition of greenhouse gases from the burning of fossil fuels (mainly petroleum, coal, and natural gas).
Although carbon dioxide is only a trace gas in earth’s atmosphere with a concentration of 0.033 per cent by volume it plays a critical role in controlling the climate of the plays a critical role in controlling the climate of the earth. Carbon dioxide influence on earth’s temperature if often called greenhouse effect.
The rate at which energy escapes the surface of the earth is over twice the rate at which the planet directly absorbs energy from the person. If this process were the only one to be occurring, the earth would be a very cold place. Fortunately, the planet does something extra to maintain the heat balance. Almost 84% of the heat radiated by the earth is absorbed by gases in the atmosphere and reradiated back to the earth’s surface. As a result of this exchange, the total energy input from the sun balances the energy output from the earth. A steady state is established, with more or less constant average terrestrial temperature It is the return of 84% of the energy radiated from the surface of the earth that has been termed the global greenhouse effect. The gases which are transparent to sunlight and are capable of absorbing IR-radiations and then re-emitting IR-radiations of longer wavelength are termed greenhouse gases
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