Canada holds 25 percent of all Arctic ice, only behind Greenland.
The Arctic is warming faster than anywhere else in the world, and its glaciers are melting. Researchers warn that Canada's Arctic glaciers are shaping up to be a massive contributor to sea level rise, which will be one of the most devastating impacts of climate change.
Over coming decades, rising sea levels could potentially displace millions of people, cause storm surges, and render swaths of coastal land uninhabitable.
Canada is home to 25 percent of Arctic ice (only Greenland has more). In the paper, published today in Environmental Research Letters, glaciologists from the University of California, Irvine found that the surface melt from ice caps and glaciers in the Queen Elizabeth Islands (in the Canadian Arctic archipelago) grew by 900 percent between 2005 and 2015, from three gigatons up to 30 gigatons per year.
Here's why that's important. There are two main contributors to sea level rise: the expansion of seawater as it heats up, and land ice melting and running off into the ocean. Using data from satellites and NASA's Operation IceBridge, which tracks ice thickness from aircraft that fly overhead, the researchers found that, before 2005, ice loss in Canada was caused equally by calving icebergs and surface melt. Surface melt now makes up 90 percent.
"After 2005, we saw a drastic increase in surface melt due to an increase in air temperature," author Romain Millan, a PhD candidate at UC Irvine, told me over the phone. (In the midst of an extreme temperature spike, it was recently about 50 degrees hotter near the North Pole than average, The Washington Post reported.)
That part of the world is warming quickly due to a bizarre effect known as polar or Arctic amplification. "Ice reflects incoming solar energy back into space," Millan explained. "When the ice melts, this energy cannot be reflected back," and is absorbed by dark ocean water. January of this year, incidentally, had the lowest Arctic sea ice extent on record.
Globally, sea level is rising "by about 3 mm per year," Thomas Wagner, cryosphere program scientist at NASA Headquarters in Washington DC, told me. (He's not an author on this study, but described himself as a sponsor of the work.) Roughly half of that comes from warming of water in the ocean, he explained. "About 20 percent of it comes from losing ice in Greenland and Antarctica," and the rest is from glaciers in Alaska and Canada.
The impacts of a melting Arctic are being felt most urgently by the people who live there. But closely tracking what's happening in Canada's North is crucial for anyone who wants to understand what sea level rise could look like, around the world, in decades to come.
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