Another way water affects climate is through cloud cover. Clouds are made up of droplets of water or frozen ice crystals suspended in the atmosphere. Generally, clouds impact climate in one of two ways.

Thick, dense clouds like this cumulus mediocris mostly reflect incoming sunlight, contributing a cooling effect. Photo: Arun Kulshreshtha

High, thin clouds, like these cirrus clouds allow sunlight to pass through them, while trapping infrared radiation from the earth, contributing a warming effect. Credit Photo: PiccoloNamek

Thin, high level clouds tend to enhance warming by letting sunlight pass through them, while trapping the infrared radiation emitted from the earth. Dense, low level clouds are more reflective and act like a shelter from the sun's incoming radiation. They reflect much of this radiation back into space, increasing earth's albedo and contributing to a cooling effect.