Page "Cloud feedback" Paragraph 1

Global warming is expected to change the distribution and type of clouds.

Seen from below, clouds emit infrared radiation back to the surface, and so exert a warming effect ; seen from above, clouds reflect sunlight and emit infrared radiation to space, and so exert a cooling effect .< ref name = hartmann-1997 > Cloud representations vary among global climate models, and small changes in cloud cover have a large impact on the climate.

Differences in planetary boundary layer cloud modeling schemes can lead to large differences in derived values of climate sensitivity.

A model that decreases boundary layer clouds in response to global warming has a climate sensitivity twice that of a model that does not include this feedback.

However, satellite data show that cloud optical thickness actually increases with increasing temperature .< ref name = tselioudis-1992 > Whether the net effect is warming or cooling depends on details such as the type and altitude of the cloud ; details that are difficult to represent in climate models.