September 3, 2008—Canada's polar scientists have had little time for summer vacation this year.
That's because they've been closely monitoring the country's Arctic ice shelves, which have crumbled at an alarming pace over the past few months.
Nearly 23 percent of the total area—more than three times the size of Manhattan—has disappeared since 2007, satellite images show (above).
In July the Ward Hunt Ice Shelf broke apart, followed by the surprise collapse in August of the Markham Ice Shelf, which is now adrift in the Arctic Ocean.
And the recently named Serson Ice Shelf has shrunk by 60 percent—an "incredible" loss, said Derek Mueller, the Roberta Bondar Fellow in Northern and Polar Studies at Trent University in Ontario.
Large swaths of open water surrounding the shelves near the northern coast of Ellesmere Island have allowed breathing room for the ice to disintegrate, Mueller told National Geographic News. (See map.)
"Highly unusual" temperatures, up to 68 degrees Fahrenheit (20 degrees Celsius) in some places, certainly aren't helping the situation, he added.
"These ice shelves are changing as the Arctic is changing," Mueller said. For instance, the rate of Arctic sea-ice loss this year is poised to break 2007's all-time low. And Mueller expects more disintegration to occur in coming months, especially in the Ward Hunt Ice Shelf, which has ribbons of cracks crisscrossing its surface.
"The overall scene is one of rapid change, and one that I'm sure has me and other polar scientists scrambling to understand as [it] occurs."