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article imageMajor ice-shelf loss for Canada

By Chris V. Thangham     Sep 3, 2008 in Environment
Canada lost a big chunk of ice-shelf, a quarter of the ice covered area that was part of an island for thousands of years.
The ice shelves in Canada’s High Arctic has been losing more areas recently this year because of warmer air temperatures and reduced sea-ice conditions that is helping them lose quickly. One such area, 50 sq. kilometers (20 sq. miles) Markham Shelf, attached to the Ellesmere Island has completely broken off and has become floating sea-ice.
Trent University's Dr Derek Mueller told BBC:
"These substantial calving events underscore the rapidity of changes taking place in the Arctic...These changes are irreversible under the present climate."
The picture shows the loss of the ice-shelf over just a year.
Ellesemere Island has taken big hits all of this year. One of its shelves, Ward Hunt Ice Shelf, the largest of Ellesemere shelves, substantial ports of ice had separated from it and the break-up is continuing. Markham, another of the four shelves had broken away from Ellesemere. The Serson shelf lost two sections totaling an estimated 122 sq. km (47 sq. miles).
The shelves themselves are merely remnants of a much larger feature that was once bounded to Ellesmere Island and covered almost 10,000 sq km (3,500 sq miles). Over the past 100 years, this expanse of ice has retreated by 90%, and at the start of this summer season covered just under 1,000 sq km (400 sq miles). Much of the area was lost during a warm period in the 1930s and 1940s.
According to the researchers, the temperatures in the Arctic are much higher now than in the 1930s and 1940s and so further deterioration will occur in the area. These shelves contain ice that is up to 4,500 years old and once lost can’t be retrieved or regrouped.
The Arctic is currently experiencing a rapid sea-ice retreat this year. The floating sea-ice normally keeps the shelves hemmed it, but when they retreat breaks occur in the shelves as seen this year. The researchers have been recording the amount of floating sea-ice for the past 30 years and the data shows they are diminishing in overall size.
Because of the retreating sea-ice and warmer air temperatures have caused the ice shelf losses in Ellesemere.
Dr Luke Copland from the University of Ottawa told BBC.
"And extensive new cracks across remaining parts of the Ward Hunt Ice Shelf mean that it will continue to disintegrate in the coming years."
The loss of ice also has global implications. The ice shelves help reflect the energy from the Sun straight back into space and help to cool the Earth. Without the ice, more Sun’s radiation will be absorbed by darker seawater and snow-free land and warm the Earth even more. With warmer temperatures, we will see further loss of ice and the dreaded cycle will continue.
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