The importance of evolving basal motion for long-term projections of glacier change

William H Armstrong Jr, Appalachian State University, Geological and Environmental Sciences, Boone, NC, United States, David Polashenski, University of Alaska Fairbanks, Fairbanks, AK, United States, Martin Truffer, University of Alaska Fairbanks, Geophysical Institute, Fairbanks, AK, United States, Gwenn E Flowers, Simon Fraser University, Department of Earth Sciences, Burnaby, BC, Canada and Robert S Anderson, University of Colorado, INSTAAR and Department of Geological Sciences, Boulder, CO, United States