Dr. J. Graham Cogley of Trent University’s Department of Geography is part of an international, multi-author team that has documented a dramatic increase in ice loss from glaciers in Canada’s northernmost islands, as reported in the study, “Sharply increased mass loss from glaciers and ice caps in the Canadian Arctic Archipelago”, published in the leading scientific journal Nature on April 20, 2011.

From 2004 to 2006, the region’s glaciers lost an average of 31 billion tonnes per year. That went up threefold to 92 billion tonnes per year from 2007 to 2009. Over all six years, the loss amounted to nearly 368 billion tonnes, the equivalent of three-quarters of the water in Lake Erie and enough to cover the global ocean to a depth of one millimetre.

The team’s study, coordinated by Dr. Alex Gardner of the University of Michigan, points directly to warmer temperatures as the drivers of melting. Each one degree Celsius increase in mean summer air temperature was matched by 64 billion tonnes of additional melting. Iceberg calving was only a minor contributor to the total loss.

Ninety-nine percent of all the world’s land ice is in the ice sheets of Antarctica and Greenland, but currently they only account for about half of the contribution to sea-level rise from glaciers, mainly by calving. The other half comes from smaller glaciers such as those in the Queen Elizabeth Islands and Baffin Island. Dr. Gardner said, “Outside of Antarctica and Greenland, we now know that the Canadian Arctic was the largest regional contributor for the years 2007 through 2009.”

“A sixth of a millimetre of sea-level rise per year might not sound like much”, said Trent’s Professor Cogley, “but it adds up, year on year, and recent studies have confirmed that the actual rise varies around the world. Some places, including the Maritimes and New England, can expect more sea-level rise than the average in coming decades.”

The six-year study period is too short to establish a trend. “Year-to-year variation in the mass balance of the glaciers is very large”, added Prof. Cogley. “Part of Trent’s role in this study was to provide long-term context, based on its involvement in field work in the Arctic going back all the way to 1959. We also helped to provide ‘ground truth’. Technically, an encouraging aspect of the study was that several independent sources of information – the laser-altimeter and gravimeter observations from orbit, Dr. Gardner’s numerical simulations, and the sparse and hard-won field measurements – all lined up beautifully.”

In addition to the University of Michigan and Trent University, the team’s workers are with the University of Alberta, Scripps Institution of Oceanography, the University of Oslo, the Royal Netherlands Meteorological Institute, the Alaska Department of Natural Resources, the Geological Survey of Canada, Westfield State University and Campbell Scientific Canada. The study “Sharply increased mass loss from glaciers and ice caps in the Canadian Arctic Archipelago”, was funded by the Natural Sciences and Engineering Research Council, the Alberta Ingenuity Fund, the Canadian Foundation for Climate and Atmospheric Sciences and the European Union’s 7th Framework Programme.