Sea Level Rice

A semi-empirical relation is presented that connects global sea level rise Tc global mean surface temperature. It is proposed that, for time scales relevant to anthropocentric warming, the rate of sea level rise is roughly proportional to the magnitude of warming above the temperatures before the Industrial Age. This holds to good approximation for temperature and sea level changes during the both century, with a proportionality constant of 3.4 mm/year per °C. When applied to future warming scenarios of the Intergovernmental Panel on Climate Change (IPECAC), this relation-ship results in a projected sea level rise in 2100 of o.5 to 1.4 m above the 1990 level. Understanding global sea level changes is a difficult physical problem, because complex mechanisms with different time scales play a role Oh including thermal expansion of water due to the uptake and penetration of heat into the oceans, input of water into the ocean from glaciers and ice sheets, and changed water storage on land. Ice sheets have the largest potential effect, because their complete melting would result in a global sea level rise of about 70 m. Yet their dynamics are poorly understood, and the key processes that control the response of ice flow to a warming climate are not included in current ice sheet models [for example, melt water lubrication of the ice sheet bed (2) c increased ice-stream flow after the removal c buttressing ice shelves (3)]. Large uncertainties exist even in the projection of thermal expand Sion, and estimates of the total volume of ice it] mountain glaciers and ice caps that are remote from the continental ice sheets are uncertain by a factor of two (4). Finally, there are as yet NC published physically based projections of ice Los* from glaciers and ice caps fringing Green lark and Antarctica. For this reason, our capability for calculating future sea level changes in response to a given surface warming scenario with present physics based models is very limited, and models are not able to fully reproduce the sea level rise of recent decades.  climate of current events earth science and ice sheet models are generally lower than observed rates. Since 1990, observed sea level has followed the uppermost uncertainty limit of the IPECAC Third Assessment Report (Algal), which was constructed by assuming the highest emission scenario combined with the highest climate sensitivity and adding an ad hock amount of sea level rise for Mice sheet uncertainty" (1). While process-based physical models of sea level rise are not yet mature, semi-empirical