Ice Dynamics and Sea Level Rise – Revising the Prediction

Dr. Knut Christianson
Physics and Environmental Studies Departments, St. Olaf College
Department of Geosciences, the Pennsylvania State University

Geophysical and paleoclimatic observations in the past decade show that the synonymity between the words glacial and slow-paced is specious.  Glaciers all over the planet have exhibited an ability to react to climate change on daily and even hourly timescales, in addition to centurial and millennial ones.  This talk presents several dramatic examples from Norway, Greenland, and Antarctica where ice responds to climate-driven change with unexpected celerity. These observations, specifically those concerning the West Antarctic Ice Sheet, indicate that predictions of sea level rise in the next century are substantial underestimates because they do not include dynamical ice flow processes which could lead to a partial or complete collapse of a marine-based ice sheet. Using biological, geological, and geophysical evidence, this talk discusses the past, current, and future behavior of the West Antarctic Ice Sheet and describes the implications for Antarctic contributions to sea level in the next 500 years.