Polar Record

Articles

Ice-shelf collapse, climate change, and habitat loss in the Canadian high Arctic

W. F. Vincenta1, J.A.E. Gibsona2 and M.O. Jeffriesa3

a1 Département de Biologie and Centre d'Études Nordiques, Université Laval, Sainte-Foy, Québec G1K 7P4, Canada

a2 CSIRO Marine Research, GPO Box 1538, Hobart, Tasmania 7001, Australia

a3 Geophysical Institute, University of Alaska, PO Box 757320 Fairbanks, AK 99775-7320, USA

Abstract

Early explorers in the Canadian high Arctic described a fringe of thick, landfast ice along the 500-km northern coast of Ellesmere Island. This article shows from analyses of historical records, aerial photographs, and satellite imagery (ERS-1, SPOT, RADARSAT-1) that this ancient ice feature (‘Ellesmere Ice Shelf’) underwent a 90% reduction in area during the course of the twentieth century. In addition, hydrographic profiles in Disraeli Fiord (83°N, 74°W) suggest that the ice-shelf remnant that presently dams the fiord (Ward Hunt Ice Shelf) decreased in thickness by 13 m (27%) from 1967 to 1999. Mean annual air temperatures at nearby Alert station showed a significant warming trend during the last two decades of this period, and a significant decline in the number of freezing degree days per annum. The ice-dammed fiord provides a stratified physical and biological environment (epishelf lake) of a type that is otherwise restricted to Antarctica. Extensive meltwater lakes occur on the surface of the ice shelf and support a unique microbial food web. The major contraction of these ice–water habitats foreshadows a much broader loss of marine cryo-ecosystems that will accompany future wanning in the high Arctic.

(Received July 2000)