Canadian scientists are sounding another environmental alarm with word that a massive Arctic ice shelf has broken free and is now adrift in the Arctic Ocean.
The 50-square-kilometre Markham Ice Shelf broke away in early August, researchers say, and two large sections representing 60 per cent of the Serson Ice Shelf have also become detached.
That means some 214-square-kilometres of Arctic ice shelves have been lost this summer, or about a quarter of what was left. It's the equivalent of more than three times the area of the Manhattan island.
"It's astounding what's happening up there right now," said Derek Mueller, a researcher at Trent University in Peterborough, Ont.
The ice shelf loss comes at a time when Arctic sea ice is at a near-record low and other significant climate change indicators are being observed in the north, Mr. Mueller said.
New cracks are forming in the Ward Hunt Ice Shelf - the largest one remaining - and it is expected to continue to disintegrate in the coming years.
More than 90 per cent of Canada's ice shelves have been lost over the past century, the bulk of those during a warm period in the 1930s and 1940s. And temperatures in the Arctic are even warmer now.
Conditions that have kept the ice shelves in balance for some 4,000 years are no longer present, Mr. Mueller said.
"The ice shelves are not regrowing," he said.
Mr. Mueller also said the ice shelves are home to unique forms of life that are at risk.
"They are actually a habitat for microbial life," Mr. Mueller said. "Not only are we losing the ice, but we're losing these unique ecosystems that go with the ice, that depend on the ice to be there."