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Canadian Arctic losing ice shelves

Two ice shelves that existed before Canada was settled by Europeans diminished significantly this summer, one nearly disappearing altogether, newly-published research reveals.

The loss is important as a marker of global warming, returning the Canadian Arctic to conditions that date back thousands of years, scientists say.

Floating icebergs that have broken free as a result pose a risk to offshore oil facilities and potentially to shipping lanes. The breaking apart of the ice shelves also reduces the environment that supports microbial life and changes the look of Canada's coastline.

Luke Copland, an associate professor in the geography department at the University of Ottawa who co-authored the research published on Carleton University's website, said the Serson Ice Shelf shrank from 79.15 square miles to two remnant sections five years ago and was further diminished this past summer.

Prof Copland said the shelf went from a 16-square-mile floating glacier tongue to 9.65 square miles, and the second section from 13.51 square miles to two square miles, off Ellesmere Island's northern coastline.

This past summer, Ward Hunt Ice Shelf's central area disintegrated into drifting ice masses, leaving two separate ice shelves measuring 87.65 and 28.75 square miles respectively, reduced from 131.7 square miles the previous year.

"It has dramatically broken apart in two separate areas and there's nothing in between now but water," said Prof Copland.

Prof Copland said those two losses were significant, especially since the Ward Hunt Ice Shelf had always been the biggest, the furthest north and the one scientists thought might have been the most stable.

Canada has the most extensive ice shelves in the Arctic along the northern coast of Ellesmere Island. These floating ice masses are typically 131ft thick - equivalent to a 10-storey building - but can be as much as 328ft thick. They thickened over time via snow and sea ice accumulation, along with glacier inflow in certain places. The northern coast of Ellesmere Island contains the last remaining ice shelves in Canada, with an estimated area of 402 square miles, said Prof Mueller.

Between 1906 and 1982, there has been a 90% reduction in the areal extent of ice shelves along the entire coastline, according to data published by WF Vincent at Quebec's Laval University.

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