Team 3694 Page 2 of 37 Introduction Strong evidence of a global warming trend exists, and powerful models have been created to estimate future climate. Temperatures have increased by about 0.5C over the last 15 years, and global temperature is at its highest level in the past millennium. Although the warming trend is quite evident, the consequences of such wide scale climate change are still poorly understood. One of the most-feared consequences of global warming is sea level rise, and for good reason toPEX/Poseidon satellite altimeter indicates that sea levels rose 3. 2+0.2 mm annually during 1993-1998. Indeed, Titus et al estimate that a 1 meter rise in sea levels could cause $270-475 billion in damages in the United States A number of complex factors underlie sea level rise. Thermal expansion of water due to temperature changes has long been implicated as the major component of sea level rise however, recent studies have shown that thermal expansion alone cannot account for a observed increases. Mass balance of large ice sheets, in particular the Greenland Ice Sheet, is now believed to play a major role in sea level. The mass balance is controlled by two major processes, accumulation(influx of ice to the sheet)and ablation(loss of ice from the sheet). Accumulation is primarily the result of snowfall ablation is a result of sublimation and melting Contrary to popular belief, however, floating ice does not play a significant role in sea level rise. By Archimedes' Principle, the volume increase Av of a body of water with density Pocean due to melting of floating ice of weight w(assumed to be freshwater, with liquid density pater ) is given by Prater Pa oceanTeam # 3694 Page 2 of 37 I. Introduction Strong evidence of a global warming trend exists, and powerful models have been created to estimate future climate. Temperatures have increased by about 0.5oC over the last 15 years, and global temperature is at its highest level in the past millennium . Although the warming trend is quite evident, the consequences of such wide scale climate change are still poorly understood. One of the most-feared consequences of global warming is sea level rise, and for good reason. TOPEX/Poseidon satellite altimeter indicates that sea levels rose 3.2 ± 0.2 mm annually during 1993-1998 . Indeed, Titus et al estimate that a 1 meter rise in sea levels could cause $270-475 billion in damages in the United States alone. A number of complex factors underlie sea level rise. Thermal expansion of water due to temperature changes has long been implicated as the major component of sea level rise; however, recent studies have shown that thermal expansion alone cannot account for a majority of the observed increases . Mass balance of large ice sheets, in particular the Greenland Ice Sheet, is now believed to play a major role in sea level. The mass balance is controlled by two major processes, accumulation (influx of ice to the sheet) and ablation (loss of ice from the sheet) . Accumulation is primarily the result of snowfall; ablation is a result of sublimation and melting. Contrary to popular belief, however, floating ice does not play a significant role in sea level rise. By Archimedes’ Principle, the volume increase ΔV of a body of water with density ρocean due to melting of floating ice of weight W (assumed to be freshwater, with liquid density ρwater) is given by         ∆ = − water ocean V W ρ ρ 1 1 (1)