Glaciers retreating fast

Photo: The Canadian Press

Icefield in the Saint Elias mountain icefield ranges in Northern B.C.

Climate change is prompting glaciers in British Columbia, Yukon and Alberta to retreat faster than at any time in history, threatening to raise water levels and create deserts, scientists say.

David Hik, an ecology professor at Simon Fraser University, said the region is one of the hotspots for warming and the magnitude of change in the glaciers is dramatic.

"Probably 80 per cent of the mountain glaciers in Alberta and B.C. will disappear in the next 50 years," he said.

The Peyto Glacier in the Rocky Mountains and part of Banff National Park has lost about 70 per cent of its mass in the last 50 years, Hik said.

"It's a small glacier but it's typical of what we're seeing," he said.

Zac Robinson, a professor at the University of Alberta, said as the climate warms, the fragmentation of some of the large ice caps in the Rockies will continue.

Glaciers are formed when snow accumulates in the winter but doesn't melt completely the following summer.

As the Earth warms at a faster rate than it did, a combination of less snow and a rapid melt is causing glaciers to recede in length and volume, Robinson said.

The first "State of the Mountains" report, co-authored by Hik and Robinson and published in May by the Alpine Club of Canada, says outside of the ice sheets of Antarctica and Greenland, Canada has more glacier cover than any other nation. Of the estimated 200,000 square kilometres of Canadian glaciers, one quarter is found in the West and the remainder are in the Canadian Arctic Archipelago.

Robinson said mountain glaciers, given their sensitivity to warming, are showing the earliest and most dramatic signs of ice loss, and the St. Elias Mountains in Yukon are losing ice at the fastest rate.

"Yukon glaciers in the St. Elias ranges have lost approximately one quarter of ice cover since the 1950s," he said.

Scientists studied the glaciers using a number of methods, including analysing old photographs and remote sensing.

Hik said the rate of melting varies in different places in the Canadian West.

"We don't have detailed measurements everywhere but where we have measurements the rates can be 25 to 70 per cent (of melt) in the last six to seven decades."

The rates of melting are similar to what is seen in the European Alps and the Andes, he said.