Rights: The University of Waikato Published 21 June 2007 Size: 570 KB

The greenhouse effect is the natural warming of the Earth’s atmosphere. Solar radiation enters the atmosphere mainly as light, and some of that radiation is absorbed by the Earth’s surface then changed to heat that is reradiated into the atmosphere where it is absorbed by greenhouse gases then reradiated back to Earth again.

Of the incoming solar radiation, 31% is reflected back to space by clouds, aerosols, the Earth’s surface and atmosphere, about 20% is absorbed by the atmosphere and 49% is absorbed by the Earth’s surface then transformed to infra-red radiation (heat) and re-radiated into the atmosphere.