Sea ice

Abstract

A long-term increase in the sea ice extent has been observed in the Arctic since about 10,000 years because of changes in Earth's orbital parameters. On shorter time scales, additional perturbations are imposed by some other natural forcings and by changes in the heat transfer between sea ice, ocean, and atmosphere. Moreover, the recent decrease of the Arctic sea ice extent is partially due to human activities - the anthropogenic radiative forcing - which will potentially lead to an ice-free Arctic in summer in the decades to come. Although no decrease in the ice extent has been observed in the Southern Ocean over the last decades, a decrease similar to the one expected in the Arctic is simulated by climate models for the late twenty-first century in response to anthropogenic radiative forcing.