The Cable

This Canadian River Disappeared in Four Days Thanks to Climate Change

Lost river is the first case of ‘river piracy’ in the modern era. Geologists say it has wreaked havoc on the local ecosystem.

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Rivers ordinarily take thousands of years to disappear or reverse their course. But for one immense river in Canada, it took four days. The Slims River in northern Canada abruptly disappeared over the course of days last year, thanks to a rapidly melting glacier at the river’s headwaters.

Melting water cut a new canyon through the Canadian Yukon’s vast Kaskawulsh Glacier during last year’s unusually warm spring. That caused water that normally runs north through the Slims river to the Yukon River to be diverted southward instead to the Alsek River and onto the Pacific Ocean. A paper published in Nature Geoscience on Monday outlined the phenomenon and pinned the blame on post-industrial climate change.

Geologists are calling it an unprecedented side effect of climate change. And it could happen to other glacial-fed rivers too, putting river-reliant ecosystems and communities in grave risk in the future.

Now all that remains of the Slims River is a slim trickle of water — and dust, said the authors. “We went to the area intending to continue our measurements in the Slims river, but found the riverbed more or less dry,” said University of Illinois geologist James Best. “The delta top that we’d been sailing over in a small boat was now a dust storm. In terms of landscape change it was incredibly dramatic.”

The Slims River’s disappearance has quickly had a dramatic impact on the ecosystem, redistributing fish populations, altering the chemistry of nearby lakes, and plaguing the region with a spate of new dust storms. Other glacial-fed rivers, ones that supply hydroelectric power and water supplies to more populated regions, could also be at risk.

The phenomenon known as “river piracy” was coined in the 19th century and describes when tectonic shifts and long-term erosion causes rivers to disappear. Geologists say the Slims River appears to be the first case of modern river piracy, and the first ever caused by climate change.

It won’t be the last, warned Lonnie Thompson, a paleoclimatologist at Ohio State University. Thompson told the Guardian similar incidents could happen in the Himalayas, Andes mountains of South America, or other parts of Alaska and Canada as climate change accelerates.

“Often these events occur in remote and poor parts of our planet and thus go largely unnoticed by the larger population but greatly impact the livelihood of many families downstream,” Thompson said.

Photo credit: Jeff Wallace/Flickr

Robbie Gramer is a diplomacy and national security reporter at Foreign Policy. @robbiegramer

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