BBC NEWS | Science/Nature | Major ice-shelf loss for Canada

BBC NEWS | Science/Nature | Major ice-shelf loss for Canada: "The ice shelves in Canada's High Arctic have lost a colossal area this year, scientists report.

The floating tongues of ice attached to Ellesmere Island, which have lasted for thousands of years, have seen almost a quarter of their cover break away.

One of them, the 50 sq km (20 sq miles) Markham shelf, has completely broken off to become floating sea-ice.

Researchers say warm air temperatures and reduced sea-ice conditions in the region have assisted the break-up.

"These substantial calving events underscore the rapidity of changes taking place in the Arctic," said Trent University's Dr Derek Mueller.

"These changes are irreversible under the present climate." "