Clouds

Seen from space, the difference between cumulus and cirrus clouds is striking. On the left are the bright white cumulus towers of thunderstorms. On the right, thin cirrus clouds are partially transparent. (Space Shuttle Photographs STS084-706-69 and STS032-88-69 courtesy NASA JSC

Although carbon dioxide gets most of the bad publicity these days as the critical greenhouse gas, the warming effect of carbon dioxide is minuscule compared to that of water vapor. Water vapor is present in such abundance throughout the atmosphere that it acts like a blanket of insulation around our world, trapping heat and forcing surface temperatures higher than they would be otherwise. At most wavelengths within the thermal infrared energy spectrum (basically heat) that get trapped within Earth’s atmosphere you barely even notice the effects of carbon dioxide because water vapor totally dominates the signal.