Smith Lecture by Leigh Stearns, University of Kansas: The Role of Water Above, Below, and at the Front of Fast Moving Outlet Glaciers in Greenland and Antarctica
The Greenland Ice Sheet is undergoing rapid changes in flow dynamics, surface melting, and mass balance. Fast-flowing outlet glaciers now account for ~70% of the annual mass loss from the ice sheet. A series of recent changes, including calving front retreat, flow acceleration, and dynamic thinning, has caused a doubling of Greenland’s contribution to sea level rise since 2000. Understanding the dynamics of outlet glaciers is critical for modeling the future stability of the Greenland Ice Sheet and predicting rates of sea level rise.
I will explore the role of water in controlling ice dynamics, on Helheim Glacier in East Greenland and on Byrd Glacier, in East Antarctica. On Helheim Glacier, increasing amounts of surface meltwater may eventually reach the bed, lubricating the ice-bed interface and causing acceleration. In Antarctica, large subglacial lakes appear to drain periodically, also causing glacier acceleration. Both glaciers terminate in the ocean, and may be responding to changes in ocean characteristics. Throughout this talk, I will outline some of the new techniques and instrumentation developments that glaciologists are using.