The summer of 2008 brought massive ice shelf reductions in the Canadian Arctic, which accounted for 23 percent of the area. According to a recent report, in addition to the July calving from the Ward Hunt Ice Shelf, the shelves along the northern coast of Ellesmere Island had a similar fate one month later, when the entire Markham Ice Shelf completely broke-up and drifted away in the Arctic Ocean.

Overall, the ice shelf lost account for 214 km2 this summer alone! “These substantial calving events underscore the rapidity of changes taking place in the Arctic,” Dr. Derek Mueller, the Roberta Bondar Fellow in Northern and Polar Studies at Trent University in Ontario explained, adding that these are irreversible changes that point to significant variations in the environmental conditions that have kept the shelves in place for thousands of years.

Ice shelves are floating ice platforms that can only be found in Antarctica, Greenland and Canada. Calving phenomena should normally take place only once in a few decades, or perhaps years, but the latest tendency reveals much shorter periods between calving events, and a more rapid ice shelf loss than before.

Over the past decades, scientists have made numerous observations on the Canadian ice shelf, which in the 20th century alone reduced by 90 percent; the ice shelf turned into several smaller ice shelves, which in turn began breaking.

The pieces of ice shelves that are now floating in the Arctic Oceans form “ice islands” that could either circulate in the Beaufort Gyre and float along the northern edge of the Queen Elizabeth Islands toward the Beaufort Sea, or enter the Canadian Archipelago, Dr. Martin Jeffries of the US National Science Foundation and University of Alaska Fairbanks explained.

Over the past 3 years, the Canadian ice shelf continued to break off the northern coast of Ellesmere Island: in August 2005, the Petersen Ice Shelf lost over one third of its area; the entire Ayles Ice Shelf calved in August 2005, forming an ice island; in July 2008, the Ward Hunt Ice Shelf calved and formed two ice islands; in the same month, the Serson Ice Shelf lost 60 percent of its area. The most recent calving is that of the Markham Ice Shelf, which completely collapsed last month.

Dr. Luke Copland, Director of the Laboratory for Cryospheric Research at the University of Ottawa explained that this summer, the ice shelf loss was directly influenced by reduced sea ice conditions and unusually high air temperatures. The prognosis for the coming years doesn’t look more optimistic, as “extensive new cracks across remaining parts of the largest remaining ice shelf, the Ward Hunt, mean that it will continue to disintegrate in the coming years.”

The recent calving once again drew alarm signals on the future of the Canadian ice shelf. The Ayles Ice Shelf break-up for example was the largest in the Canadian Arctic in the past three decades, and according to the Canadian Ice Service, the ice was suspected to be 4,500 years old.