The mountains of British Columbia cradle glaciers in west Canada are in rapid retreat, which has become a major climate change issue, local news agency said Sunday, citing an American state-of-the union report on climate change.

"Most glaciers in Alaska and British Columbia are shrinking substantially," The Canadian Press quoted the U.S. National Climate Assessment as saying.

Glaciers in British Colombia and America's northern state of Alaska are losing 20 to 30 percent of what is melting annually from the Greenland Ice Sheet, the report said, adding that amounts to about 40 to 70 gigatons per year, or about 10 percent of the annual discharge of the Mississippi River.

"The global decline in glacial and ice-sheet volume is predicted to be one of the largest contributors to global sea- level rise during this century," the report said.

Brian Menounos, a geography professor at the University of Northern British Columbia and one of the scientists involved in cross-border, multi-agency research into glacial loss, said he was concerned about the melting speed of the glaciers.

"We've seen an acceleration of the melt from the glaciers," he said, adding, "When we start to look at some of these individual mountain ranges, we're seeing some rates that are truly exceptional."

There are 200,000 glaciers on Earth, 17,000 of them in British Columbia, according to the report.