4000-year-old ice shelf splits up


The 4,000-year-old Milne Ice Shelf, the second largest ice shelf in the Arctic Ocean, has broken up after a hotter than normal summer in Canada.

The Canadian Ice Service said satellite photos showed that about 43% of Canada’s last intact ice shelf broke away between July 30 and 31.

By 3 August, this iceberg, or “ice island”, had itself ruptured in two, with both segments then seen to drift out into the Arctic Ocean.

Planet Earth has now released imagery of the broken Milne Ice Shelf, a fragment of the former Ellesmere Ice Shelf in the Qikiqtaaluk Region, Nunavut, Canada.

Two giant icebergs formed along with lots of smaller ones, and started drifting away, Canadian Ice Service analyst Adrienne White said. The biggest is nearly the size of Manhattan — 21 square miles (55 square kilometres) and 7 miles long (11.5 kilometres). They are 230 to 260 feet (70 to 80 metres) thick.

“This is a huge, huge block of ice,” White said.

The Milne Ice Shelf before it broke up. Photo: Planet Labs

The 72-square mile (187 square kilometre) undulating white ice shelf of ridges and troughs dotted with blue meltwater had been larger than the District of Columbia but has been reduced to 41 square miles (106 square kilometres).

Temperatures from May to early August in the region have been 9 degrees (5 degrees Celsius) warmer than the 1980 to 2010 average, University of Ottawa glaciology professor Luke Copland told Inquirer News. This is in addition to the Arctic warming faster than the rest of the globe.

“Without a doubt, it’s climate change,” Copland said, noting the ice shelf is melting from both hotter air above and warmer water below.

“The Milne was very special,” he added. “It’s an amazingly pretty location.”

Ice shelves are hundreds to thousands of years old, thicker than long-term sea ice, but not as big and old as glaciers, Copland said.

Canada used to have a large continuous ice shelf across the northern coast of Ellesmere Island, but it has been breaking apart because of man-made global warming, White said.

By 2005 it was down to six remaining ice shelves but “the Milne was really the last complete ice shelf,” she said.

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