We all know that Greenland is losing a lot of ice. If you take NASA’s word for it, it’s currently losing ice mass to the tune of 287 billion tons per year, enough to raise sea levels the better part of a millimeter annually. Overall, it contains enough ice to potentially raise sea levels by as much as 20 feet.
No wonder, then, when it comes to glacial loss and sea level rise, Greenland gets all of the attention (in the Northern Hemisphere, anyway). But as new research suggests, it’s far from the only major ice loser in the region.
We pay far too little attention to two others: the northern and southern glaciers of the Canadian Arctic archipelago. The northern region, centered on Ellesmere Island, contains more glacier mass than any other region in the world (outside of Greenland and Antarctica, that is), and the southern region, centered on the vast Baffin Island, also holds a very large amount of ice.
And they’re both fast losing ice. “If you do an entire inventory of all the glaciers, they actually are changing more than Greenland and Antarctica at the moment, or have been,” says Princeton geoscientist Christopher Harig, who conducted the new study in Geophysical Research Letters along with Princeton’s Frederik Simons.
Baffin Island is one of the five biggest islands in the entire world, according to the U.S. Geological Survey. Its two largest ice caps, named Barnes and Penny, are “thought to be the last remnants of the Laurentide Ice Sheet” that once extended across much of North America, the survey says.
Ellesmere Island is arguably even more spectacular — like Antarctica (but on a considerably smaller scale), it is actually the home to significant ice shelves, or sheets of ice that extend over the ocean and hold back glaciers behind them as they flow into the sea. These are all located on the northern side of Ellesmere Island, facing the North Pole.
According to Environment and Climate Change Canada, these ice shelves have already been severely damaged as warming advances. In August 2005, the “entire Ayles Ice Shelf broke away,” says the agency, leaving just five remaining. When Ayles broke up, fully 7.5 percent of all of Ellesmere Island’s ice shelf area was lost in the space of an hour, a 2007 study found. And many of the remaining shelves have also lost major portions since then.
So what does it all add up to?
Harig and Simons used gravity data from NASA’s twin GRACE satellites to measure the ice mass loss from Greenland, these island-based Canadian glaciers (treating Ellesmere and Baffin as regions made up of multiple surrounding islands, not just single islands), and the Alaska region between 2003 and 2013.
You won’t be shocked to learn that Greenland is losing the most ice — they put the total at 244 billion tons per year, with an acceleration of 28 billion tons annually. That’s pretty close to NASA’s overall figure. And the acceleration, if it were to continue, would mean that Greenland’s current rate of ice loss would double in 10 years.
However, what’s striking is just how much mass is also vanishing from the Ellesmere and Baffin regions. Ellesmere, the study suggests, is losing 38 billion tons per year, and Baffin is losing 22 billion tons per year. Both are also seeing accelerating losses. The Gulf of Alaska region, the study found, is losing another 40 billion tons per year (other recent research put this higher, at 75 billion tons, for all of Alaska).
Thus, if you add up Alaska and the two Canadian regions, you get around 100 billion tons of ice loss per year, which is nothing to sniff at. No, it’s not Greenland. But then again, it’s actually not far from current estimates for total loss from Antarctica, which NASA puts at 134 billion tons per year.
Harig explains that overall, glaciers around the world contain about 412 millimeters — or roughly 16 inches — of potential sea level rise. Of this, 92 millimeters’ worth is to be found in the Ellesmere or northern Canadian glacier region, which makes it the single largest repository of land-based ice outside of Greenland or Antarctica. Baffin, Harig says, contains about 21 millimeters’ worth.
The key difference, and the reason why Greenland and Antarctica get all of the attention, is that their loss in the future is feared to grow further — and that they simply have so much to give. So far, they’re still only losing a trickle of their potential. By contrast, with these Canadian and Alaskan glaciers, the concern is that they will continue to lose ice, but become less significant contributors to sea level rise as the 21st century advances — and the two giants take over.
“There are a lot of different glacier areas, and they’re all very different,” says Harig. “Their number isn’t really large compared to Greenland and Antarctica until you add them up together.”
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