Since high clouds are thin, they also allow sunlight to pass through to warm the ground. High clouds then have a warming effect. The formation of predominantly high clouds would support the positive feedback theory. Global warming would increase the amount of water vapor in the atmosphere, which may bring about an increase in global cloudiness, absorbing more infrared radiation and enhancing the Greenhouse Effect. The percentage of radiation reflected from a surface is called the albedo.
Thick clouds have a higher albedo than thin clouds.
Clouds reflect upwards about 20 percent of the total incoming solar radiation, a cooling process. They absorb about 3 percent of incoming solar radiation and absorb infrared radiation from the Earth, a warming process. Summary Current research supports the strong influence of clouds upon climate. Researchers at the British Meteorological Office altered the representation of clouds in their climate model. Initially, the model projected a global temperature rise of about 5 degrees Celsius, accompanying a doubling of atmospheric carbon dioxide.