Predicting future ice sheet changes Despite widespread greenhouse skepticism glaciologists are increasingly worried that the effects of global warming may be more dramatic and felt sooner than expected. The Greenland and West Antarctic Ice Sheets are losing ice at much faster rates than has been predicted, while the mechanisms causing this are not yet fully understood. The consequence may be that, even in this century, coastal areas will be flooded worldwide.
Several sessions discuss new satellite data that clearly document major changes in the ice sheets. Isabella Velicogna will present new satellite gravity data that independently confirm volume loss observed by radar sattelites. Eric Rignot found evidence that basal lubrication (by soft sediments underlying the glaciers) is one of the causes for accelerating ice flow. Jonathan Bamber will present surprising new evidence indicating that a similar process, known from the West Antarctic Ice Streams, may be going on in the East Antarctic Ice Sheet as well. In his Louis Agassiz Medal lecture, Richard Alley will expand these observations to lessons for the future, particularly for policymakers.
Participants: - Richard Alley: Projecting ice-sheet changes (Agassiz Medal lecture) abstract
- Eric Rignot: Rapid changes of the Greenland Ice Sheet from InSAR
"None of the physical processes involved with glacier acceleration in east Greenland in response to climate warming (enhanced basal lubrication, ungrounding of glacier fronts, ice-shelf removal, enhanced submarine melting at calving faces etc.) are included in models used to predict the future of the ice sheet. In effect these models underpredict what the contribution of Greenland to sea level might be in the future." abstract
see also Media Tip - Isabella Velicogna: GRACE measurements show large ice mass loss in Antarctica and Greenland
"... during 2002-2005, we use[d] 34 monthly GRACE gravity fields to estimate the linear trends in Greenland and Antarctic ice mass. This represents a new and independent estimate of the polar ice sheet mass balance. Both ice sheets display a large mass imbalance during the analyzed period." abstract - Jonathan Bamber: East Antarctic Ice Stream underlain by major sedimentary basin
"... we believe that the existence of the sedimentary basin is the likely cause of the higher estimated basal sliding velocities ... [which] has implications for how ice dynamics in East Antarctica are modelled." abstract
Session: CR1 Open session on cryospheric sciences (including Louis Agassiz Medal Lecture) | >>programme
Session: CR11/G12 Observations of glaciers and ice sheets from space | >>programme
Richard Alley ralley@geosc.psu.edu
Isabella Velicogna isabella@giove.colorado.edu
Eric Rignot eric@pib.jpl.nasa.gov
Jonathan Bamber j.bamber@bristol.ac.uk
