The Response of the Greenland Ice Sheet to Holocene Climate Change: Testing Ice Sheet Models and Forcing Mechanisms of Ice-Margin Change

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Ice sheet response to climate change is a growing concern in light of recent rapid climate warming over Greenland. A consensus among scientists is that oceanographic conditions (e.g., temperature and currents) play a critical role in controlling rates of ice sheet retreat. This project will generate reconstructions of western Greenland Ice Sheet change across a wide geographic corridor that encompasses both marine- and land-terminating sectors of the Greenland Ice Sheet. Measurements from these locations will help demonstrate the different mechanisms thought to control ice margin response to climate change. The project will combine geological reconstructions of past ice margin change and remote sensing and photogrammetry methods to generate records of ice margin change throughout the Holocene, up to and including the 20th century. The geological reconstructions take advantage of untapped archives of former ice margin positions contained within proglacial lakes. In addition, cosmogenic 10Be dating will generate records of early Holocene ice margin recession that took place for both marine- and land-based glacier termini. Records of 20th century ice margin change will take advantage of recently produced spatial datasets such as aerial-photograph-based topographic maps, satellite images, laser and radar data that provide high-resolution images of the ice sheet bed and its surfaceDespite the potential of the Greenland Ice Sheet to contribute dramatically to sea level rise in response to ongoing and projected climate change, resulting in significant socio-economic impacts in the US and around the globe, the future behavior of the ice sheet remains largely uncertain. This uncertainty stems from our incomplete knowledge of the pattern and timescales of the ice sheet's response to climate change. This, in turn, stems from a relatively brief view that we have of ice sheet change, which is limited to several decades. This project will improve our understanding of what controls ice margin change based on how different types of ice sheet sectors have responded to climate changes over the last 10,000 years. By combining these results with marine records and other ice margin and climate reconstructions, the findings of this project will be useful in forecasting future ice sheet and sea level change.