Branch Seminar Series: Tom Neumann

University of Vermont/Geology Department
Seasonal changes in ice velocity, depending upon their extent both spatially and temporally, may be important considerations when assessing the stability of inland glacier ice. Work by Zwally and others (2002) suggested potential ice sheet instability in Greenland due to the penetration of summer melt water from the surface of the ice sheet to the bed, where promotes glacier sliding. The implication is that this process could lead to rapid disintegration of the Greenland ice sheet as surface melt becomes more common in a warming climate. The IPCC 4th Assessment Report does not include dynamic responses in projections of sea level rise; consequently, current estimates of sea level rise may be too low. In this presentation, I present recent surface velocity and ice-penetrating radar data collected from the vicinity of Swiss Camp, a site near the equilibrium line on the west coast of Greenland. These data show the ice sheet response depends on the proximity to the drainage event, and on the configuration of the subglacial system. I discuss the role seasonal velocity variations play in the potential instability of the Greenland ice sheet, and suggest experiments to better predict ice sheet response.