On Thermal Expansion over the Last Hundred Years

Estimates of sea level rise during the period 1856–1991 due to thermal expansion are presented. The estimates are based on an ocean model that consists of three zonally averaged ocean basins representing the Atlantic, Pacific, and Indian Oceans. These basins are connected by a circumpolar basin that represents the Southern Ocean. The ocean circulation in the model was prescribed. Surface ocean forcing was calculated from observed sea surface temperatures. Global mean forcing and regionally varying forcing were distinguished. Different parameterizations of ocean heat mixing were incorporated. According to the model presented, global mean sea level rise caused by thermal expansion over the last hundred years ranged from 2.2 to 5.1 cm, a best estimate being 3.5 cm.