Climate Feedbacks

Abstract

In response to an Earth energy surplus from factors like increasing carbon dioxide, the climate system warms. This allows the Earth to shed additional heat to space through the Planck response. This response, however, is modified by additional radiative feedbacks that act to amplify or dampen the amount of warming necessary to restore equilibrium. These feedbacks, which are due to changes in water vapor, lapse rate, surface albedo, and clouds, are discussed herein. Water vapor is the strongest positive feedback, with cloud and surface albedo feedbacks being smaller, positive feedbacks. The lapse-rate feedback acts negatively, offsetting some of the water vapor feedback. Cloud feedback involves various cloud formation processes and depends on the spatial pattern of planetary warming, making it the most uncertain feedback. Together, these processes determine the climate sensitivity, the total amount of warming per unit of radiative forcing.