AOSC Departmental Seminar
April 2, 2015

Redefining Glacial Pace: Greenland Ice Sheet Velocities during the 21st Century

Twila Moon
National Snow and Ice Data Center, CIRES, University of Colorado, Boulder

Projections for sea level rise in the year 2100 exceed 1 m for business-as-usual emissions, yet the projection range remains wide. Ice sheet mass loss is a primary contributor to sea level rise and, currently, the Greenland Ice Sheet contributes ~0.7 to 1.1 mm/yr to sea level (260-380 Gt/yr of ice). Roughly a third to a half of Greenland’s mass loss is due to marine-terminating outlet glacier ice discharge, mostly via calving, which depends in large part on ice velocity. Our understanding of why and how quickly glacier motion changes, however, is limited. As recently as the late 1990’s, glaciologists viewed ice sheets as relatively slow-changing (decades to centuries) features, expected to play little role in the immediate effects of climate change. The development of sophisticated remote sensing tools, however, has allowed us to discover the fast-pace (days to years) of ice sheet change, making them a direct player in current climate impacts. In this talk, Dr. Moon will discuss the first results to characterize Greenland outlet glacier annual velocity fluctuations on an ice-sheet-wide scale. She will also explore the developing understanding of seasonal glacier velocity patterns in the northwest, west, and southeast, the regions of the ice sheet with the highest ice discharge. Finally, Dr. Moon will look at recent advances in understanding the environmental and climate mechanisms driving velocity change, and ice discharge, in Greenland. Together, this work increases our understanding of the ice sheet response to climate change, a necessity for improving future projections of sea level rise.