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.’ Scientists reported in July that substantial slabs of ice had calved from Ward Hunt Ice Shelf, the largest of the Ellesmere shelves. Similar changes have been seen in the other four shelves. As well as the complete breakaway of the Markham, the Serson shelf lost two sections totalling an estimated 122 sq km (47 sq miles), and the break-up of the Ward Hunt has continued. Cold remnants The shelves themselves are merely remnants of a much larger feature that was once bounded to Ellesmere […]