ARCUS | Arctic Research Consortium of the United States

7th Annual ARCUS Award for Arctic Research Excellence

Honorable Mention Physical Science
Submitted by   David Burgess
Authors   David Burgess and M. J. Sharp
Category   Physical Science
Title   Recent Changes in Areal Extent of the Devon Ice Cap, Nunavut, Canada
Affiliation   Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, Canada

Abstract

Multi-temporal image data from the years 1959/1960 and 1999/2000 reveal a 2.3% decrease in the surface area of the Devon ice cap, Nunavut, over the last 40 years. This has resulted primarily from extensive retreat of tidewater glacier margins on the eastern side of the ice cap, and shrinkage of its near-stagnant south-western arm. Thinning of the ice cap has also increased bedrock exposure in the ice cap interior. However, the north-western margin of the ice cap has advanced slightly since 1960. Volume loss associated with these changes was estimated at –65 +/- 5 Km3 as calculated from volume-area scaling techniques (Bahr, et al, 1997). A DEM of the ice cap surface was used to delineate drainage basin boundaries, to allow patterns of change to be investigated on a regional scale. Strong correlation between the hypsometric characteristics of drainage basins and the observed changes in ice cap geometry suggests that these changes reflect inter-basin differences in the inherent sensitivity of glacier mass balance to recent climate forcing. Response time calculations indicate that most of the ice cap is responding to recent climate warming whereas the north-western region is likely still responding to cooler conditions that prevailed during the Little Ice Age (LIA).