Write notes on : Greenhouse effect

Explanation

It is naturally occurring phenomenon that is responsible for heating of earth.s surface and atmosphere. In the absence of greenhouse gases the average temperature of earth would have been a chill-`18^@` C reather than the present average of `15^@` C.
These gases rediate heat energy and a mahor part of which again comes to earth.s surface thus heating it up once again. This cycle is repeated again and again.
High levels of greenhouse gases (`CO_2, CFC_s,` etc.) in the atmosphere allow the heat waves to reach earth but prevent their escape and the earth becomes warm.
This gradual continuous increases in the average temperature of surface of the earth causes global warming.