[Reeses]

Water vapor is invisible but clouds reflect all wavelengths including infrared. The total amount of water vapor in the air stays about the same but whether the vapor condenses into clouds or not is dependent on the availability of nucleotides. By helping nature make clouds we can reflect up to 95% of sunlight back out to space, cooling the Earth below. Water vapor is much more complex than a simple greenhouse gas.

[js1138]

http://archives.cnn.com/2000/NATURE/10/09/clouds.warming.enn/index.html