North American glaciers spanning Canada and the US are shrinking at an unprecedented rate due to climate change, according to Canadian scientists.
In a recent survey of the Yukon, a territory of northwestern Canada, scientists found that glaciers in the Saint Elias Mountains are losing ice “faster than the rest of the country,” The Guardian reported on Tuesday. The mountain range spans three national parks in Canada and the US, and is home to one of the world’s largest ice fields outside of Greenland and Antarctica.
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Saint Elias lost 22 percent of its ice cover between 1957 and 2007, according to The Guardian. And 6.6 square miles of ice disappeared from Saint Elias’ Kaskawulsh Glacier, called the “highway of ice,” between 1977 to 2007 where temperatures have risen 3.6 degrees Fahrenheit in the past 50 years, reported CBC News on Sunday. Scientists have tracked glacier retreat by collecting measurements of glacier area and mass, and have also analyzed aerial photographs to better understand changes to their boundaries.
“The region is one of the hotspots for warming, which is something we’ve come to realize over the last 15 years,” David Hik, professor of terrestrial ecology at Simon Fraser University, told The Guardian. “The magnitude of the changes is dramatic.”
Hik co-authored a 2018 report issued by the Alpine Club of Canada called the “State of the Mountains.” The first of its kind, and meant to highlight the impacts of climate change throughout the country’s alpine regions.
Over the last 50 years, one-quarter of the rise in global sea level caused by the shrinking of glaciers around the world “is believed to come from glaciers bordering the Gulf of Alaska,” the report estimates.
“We’re seeing a 20 percent difference in area coverage of the glaciers in Kluane National Park and Reserve and the rest of the UNESCO World Heritage site [over a 60-year period],” Diane Wilson, a field unit superintendent at Parks Canada, told CBC News. “We’ve never seen that. It’s outside the scope of normal.”
Glaciers like Kaskawulsh are diminishing at an alarming rate, and are unable to compensate for the volume they’re losing each year, says CBC News. Glaciologists mapping Kaskawulsh—which is situated within Canada’s Kluane National Park and Reserve, a UNESCO World Heritage site, and covers an area of more than 15,000 square miles—have detected ice at depths of more than 2,624 feet using radar, but say the glacier is retreating at a rate of 1.6 feet per year.
As glaciers shrink, so do meltwater supplies, as was the case with Kluane Lake, which depends on glacial runoff from Kaskawulsh fed by the Slims River. In 2016, the Slims River dried up—a phenomenon called “river piracy,” or the diversion of a stream or river to another body of water, that hadn’t occurred there in 350 years. Rather than flowing into the Slims River, Kaskawulsh’s meltwater changed its course, heading in the opposite direction toward the Kaskawulsh River, and ultimately caused Kluane Lake to drop more than 5.5 feet, where it currently remains.
Exposed sediment from a barren Slims River now also creates huge dust storms along the Alaska Highway where it across the area the river once flowed.
“We know of no other historic examples of large-scale, permanent river piracy comparable to that at Kaskawulsh Glacier in 2016,” the report states. “As we move toward a world with far fewer glaciers and smaller ice sheets, land that has been covered continuously by ice for many tens of thousands of years will become ice-free.”
Zac Robinson, a mountain historian and professor at the University of Alberta who co-authored the report, told The Guardian that 80 percent of the ice cover in the Rocky Mountains, which also span the US and Canada, could vanish in 50 years.
In its annual Arctic Report Card released in 2017, the National Oceanic and Atmospheric Administration warned that Arctic temperatures are rising twice as fast as the rest of the planet, and called the phenomenon a “new normal” and “unprecedented transition in human history.”
