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Canada’s Milne ice shelf collapsed’

  • Category
    Climate Change
  • Published
    17th Aug, 2020

The collapse of Canada’s Milne ice shelf — the country’s last one — in a corner of the country’s Ellesmere Island, has increased fears of the Arctic region being under severe stress due to global warming.

Context

The collapse of Canada’s Milne ice shelf — the country’s last one — in a corner of the country’s Ellesmere Island, has increased fears of the Arctic region being under severe stress due to global warming.

About

  • Located on the northwestern coast of Ellesmere Island in Nunavut, the Milne Ice Shelf is about 4,000 years old.
  • The Milne ice shelf lost more than 40 percent of its ice over two days end of July 2020.
  • The shelf's sudden collapse was a close call for scientists studying ice loss in that precarious location, said Arctic ice researcher Derek Mueller.
  • The Milne ice shelf lost more than 40 percent of its ice over two days end of July 2020.
  • This has increased concerns over the rapid melting of ice and the breaking of old ice shelfs — large floating pieces of ice that form when a glacier or ice sheet flows into the sea surface.
  • This also meant the last known epishelf lake — a water body dammed by the ice shelf and floating on the ocean surface — in the northern hemisphere and on the Milne ice shelf, no longer exists

What are Ice shelves?

  • An ice shelf is a thick, floating slab of ice that forms where a glacier or ice flows down a coastline. Ice shelves are found only in Antarctica, Greenland, and Canada. Thicknesses of floating ice shelves range from 100-1,000 meters.
  • Ice shelves are formed by forces of gravity from ice along the shore. Gravity constantly pressures the movement of ice from the land to the shelf. Ice shelves lose mass when chunks break off and slide into the ocean water. Shelves gain mass by snow accumulation on the upper surface.
  • Ice shelves can date as back as far as hundreds to thousands of years. They are thicker than long-term sea ice, but not as large as glaciers.
  • The world’s largest ice shelves are the Ross ice shelf and the Filchner-Ronne ice shelf in Antarctica. 

Ellesmere Island

  • Canadian ice shelves are attached to Ellesmere Island. The Ayles ice shelf broke up in 2005, the M’Clintock ice shelf broke from 1963 to 1966, and the Markham ice shelf broke up in 2008.
  • The only Canadian shelves still existing was the Milne ice shelves.
  • Ellesmere Island has been losing ice for more than a century.
  • About 100 years ago, a vast, single ice shelf extended along the island's northern coast, spanning more than 3,300 square miles (8,600 square km).
  • By 2000, the shelf was reduced to around 405 square miles (1,050 square km) divided among six large ice shelves — including Milne Ice Shelf — as well as a few smaller ones, Carleton University representatives said.
  • Since 2003, there have been five major calving events on the Ellesmere Island coast, and there's no question that climate changeis driving the drastic ice loss.

The recipe for ice shelf break up

  • Temperatures from May to early August in the region have been 5 degrees Celsius warmer than the 1980 to 2010 average, University of Ottawa glaciology professor Luke Copland said.
  • The high temperatures combined with a warming pattern that is much faster than the rest of globe are to blame for the disintegration of the ice shelves.
  • Above-normal air temperatures, offshore winds and open water in front of the ice shelf are all part of the recipe for ice shelf break up.
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