A tipping point was reached in Canada’s Yukon Territory when the accelerated melting of the large Kaskawulsh Glacier triggered a phenomenon that has never been seen before. The phenomenon is known as “river piracy” when one river catches the flow of another. This river piracy was known to have had happened in the past due to the studies of changes in our world’s climate history. But that last happened thousands of years ago, and most people alive have never heard of it before. The phenomenon has been attributed to our burning of fossil fuels where gas emissions have changed our climate.
While much of the focus of studies on melting glaciers has been focused on their contributions to sea level rise, the new research, detailed Monday in the journal Nature Geoscience, shows that climate change can have unexpected impacts with potentially large consequences, the authors say.
Meltwater has broken through the weakened ice of the Kaskawulsh Glacier.Hakai Magazine explains what happened in the wilds of the Yukon.
“This is a kind of unanticipated consequence of climate change that, until it happened, we didn’t know it was going to happen,” Shugar says. “Or, we didn’t know it was going to happen now.”
Shugar says the theft had been in the works for more than 100 years. But in the spring of 2016, something tipped and a river was whisked away.
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In southwestern Yukon, 2016 was a particularly warm year, and the Kaskawulsh Glacier—known to the local Southern Tutchone First Nation as Tänshı̨̄—was in sorry shape. The glacier normally fed the Slims River (or Ä’äy Chừ), which flowed northward into Kluane Lake, continued into the Kluane River and, eventually, the Bering Sea. But the mass of the glacier itself had created a topographic divide, which disappeared as the ice shrank. Last year, its leading edge had retreated to a point where the land sloped steeply southward. The meltwater, which would normally flow north into the Slims River, went down this new path, into the Kaskawulsh River, instead.
“Water that should have gone out the Slims River actually carved its way through this thin, decaying toe of ice,” says Shugar, who detailed the mechanics of the collapse in a recent paper. And as the water disappeared from the Slims, it had a big effect on the watershed.
The water level in Kluane Lake has dropped so sharply that parts of its bed are now exposed.Inside Climate News reports on the alarm bells that have gone off on the rapidity of climate change processes that have not been predicted to occur.
Although Shugar said this event is not likely to become common because few glaciers today have dual drainage systems, it does set off alarm bells over global warming's rapid effects.
"When we typically think of climate change impacts, we think of issues that are fairly slow to occur," such as sea level rise and the tree line marching further north, Shugar said.
"But what our study demonstrated is that sometimes perhaps underappreciated consequences of climate change can and will occur on timescales that are very rapid...things that occur over the course of a single year."
The reorganization of the glacier's drainage system was so sudden it caught even the researchers off guard.
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