Collaborative Research: Testing Arctic Ice Sheet Sensitivity to Abrupt Climate Change

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A team of investigators proposes to investigate the response of the Laurentide and Greenland Ice Sheets to two short term cooling events (several decades to a few centuries in duration) that occurred 9.3 and 8.2 thousand years ago. Assessing the sensitivity of ice sheets to short term climate variability is at the forefront of the scientific community's and the public's interest because short term ice sheet change will drive 21st century sea level rise. Thus a central question of the proposed work is whether ice sheets react abruptly to climate forcings, or are multi-millennial-scale trends in climate required to elicit a large-scale ice sheet response?The investigators propose an intensive field-based research program capitalizing on their newly published work reconstructing ice sheet change using high-precision beryllium-10 dating to test the hypothesis that prominent moraine systems marking former ice extents in West Greenland and Baffin Island record the synchronous advance of the Greenland and Laurentide ice sheets driven by the abrupt cooling events 9.3 and 8.2 thousand years ago. Pilot data reveal that portions of the ice sheet margin that are in contact with the surrounding ocean are able to respond rapidly to a short-lived climate perturbation. To test whether these documented changes were restricted to solely the most sensitive marine-terminating ice sheet sectors, or whether ice sheets are capable of a larger scale response to centennial-scale climate change, well-constrained chronologies of ice sheet change are needed from other regions. The investigators' research objectives are to 1) establish how land-terminating regions of ice sheets, which are more representative of broader ice sheet margins, respond to abrupt climate change, 2) further evaluate the role that oceanic forcing plays in modulating ice sheet response to short-lived climate perturbations, and 3) reconstruct the early Holocene behavior of mountain glacier systems (a proxy for summertime temperature) to evaluate what climatic conditions influenced the ice sheets. The investigators will work to make results easily accessible to the public. The work is led by an early career investigator and will support two graduate and several undergraduate students.