If it's true that every picture tells a story, then two pictures tell an epic tale. Consider this pair of images, taken just four days apart this summer eight years apart by a NASA satellite. They document the same north coast expanse of Canada's Ellesmere Island in Nunavut, which is bounded by the Arctic's largest ice shelf:
August 18, 2010. Credit: NASA Earth Observatory
August 22, 2002. Credit: NASA Earth Observatory
The big white field -- which shows some cracks in the top image, and is completely fractured in the bottom image -- is a Bermuda-sized chunk of sea ice breaking away from the the Ward Hunt Ice Shelf
Estimated at around 130-feet thick, scientists have judged the Ward Hunt to be stable for 3,000-6,800 years, based on carbon-dating of driftwood and narwhale remains found on the Ellesmere coastline.
But recent upward trends in the Earth's mean surface temperature seem to have stressed the ice shelf: it cracked and calved massive icebergs in the spring and summer of 2002, [Update: as the bottom photo shows] and underwent another breakup in 2008.
With this summer's breakup, "The cracks are going right to the mainland, basically, right to Ellesmere Island," a professor of earth and atmospheric sciences, John England of the University of Alberta, told Canada's CBC News earlier this week.
"So, in the core of the ice shelf itself, the fracturing is occurring," said England. "I think that's really quite significant, that it's like the most resistant and most tenacious part of the ice shelf is now being dismantled."
This year's Arctic conditions put a particularly dismal spin on US failure to enact climate and energy policy reforms. (See "Beyond Oil: Activism and Politics" by Bill McKibben.) This spring was the warmest in the Arctic since 1948, according to the National Snow and Ice Data Center, with some regions of the Western Canadian Arctic more than 11°F above historic temperatures. This summer's sea ice melt has been extensive, according to the center: As of August 16, 2010, Arctic summer sea ice covered about 2.30 million square miles, 649,000 square miles below the average extent from 1979 to 2000.
With a month of melting season still to go, 2010's summer Arctic ice extent is already the third-lowest on record -- trounced only by the record-setting lows of 2008 and 2007.
