describe greenhouse effect?
The radiation from the sun enter the Earth’s atmosphere but are unable to escape. This increases the temperature of the Earth. This is called the greenhouse effect.
When radiation from the sun strike the earth and are reflected back, the gases present in the atmosphere of earth like CO2, CO, CH4 absorb heat energy and do not let these radiation to go back. As a result the temperature of the earth increases. The earth is warmer because of presence of these gases, as they prevent escape of heat. Without greenhouse effect the temperature of earth would have been -18ºC.
The greenhouse effect refers to circumstances where the short wavelengths of visible light from the sun pass through a transparent medium and are absorbed, but the longer wavelengths of the infrared re-radiation from the heated objects are unable to pass through that medium. The trapping of the long wavelength radiation leads to more heating and a higher resultant temperature. Besides the heating of an automobile by sunlight through the windshield and the namesake example of heating the greenhouse by sunlight passing through sealed, transparent windows, the greenhouse effect has been widely used to describe the trapping of excess heat by the rising concentration of carbon dioxide in the atmosphere. The carbon dioxide strongly absorbs infrared and does not allow as much of it to escape into space.