The Devon Island ice cap, which covers an area of about 14,400 square kilometres, is located to the west of Baffin Bay. In a paper published in the journal Arctic, a team led by Sarah Boon of the University of Lethbridge in Alberta reported that between 1961 and 1985, the ice cap grew in some years and shrank in others, resulting in a roughly steady overall ice mass. But in 1985, ice volume and area began to steadily decline.

The researchers place the blame on warmer summers. The High Arctic receives very little precipitation, so accumulation of snow and ice in the winter and cool summers, when temperatures are below freezing, can be extremely slow. A single warm summer can then wipe out five years of growth. The past decade has seen four years with unusually warm summers, resulting in significant ice loss. ‘What we see during these warm summers is the extent of the melt is greater,’ Boon said.

The retreating ice exposes dark soil and rock, which accelerates loss at the ice edge. However, it isn’t only the periphery of the ice cap that is losing ice; according to the researchers, the ice is also thinning at lower altitudes. There has also been an increase in the calving of icebergs from the outlet glaciers that flow into the ocean.

June 2010