Kaskawulsh glacier
Photo by Dan Shugar

A river in the Yukon has changed direction, and climate change is the culprit

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You’d think you’d be able to rely on a river to always flow in the same direction, but apparently that’s not the case, as a River in the Yukon recently proved by abruptly changing its course.

The Yukon’s Kaskawulsh Glacier used to melt into the Slims River, flowing north through Alaska and into the Bering Sea. However, over the course of just four days, the river changed direction and now flows a short distance south and empties into the Gulf of Alaska. The Slims River itself has nearly vanished.

It’s known as “river piracy”—the phenomenon whereby a river is diverted from its course and joins another river instead. And while river piracy has been known to happen as a result of shifting tectonic plates or landslides, scientists say this is the first time that it’s occurred due to man-made climate change.

According to Dan Shugar, a geoscientist and lead author of a recently published study on the river, the river changed direction because the Kaskawulsh Glacier has shrunk. With the rapid melting of the glacier, the ice retreated so far that it began to flow into the south-running Kaskawulsh River instead of the Slims, raising the water level of the Kaskawulsh considerably. “It’s 99.5% [certain] that it occurred due to warming over the industrial era,” James Best, a geologist with the University of Illinois, told the Guardian.

Shugar and Best discovered the change in the river last summer, when they went to the area to study changes in the river. What they found instead was that the river itself had slowed to a trickle. “We went there anticipating low flow and it turned out to be no flow,” Shugar told the CBC. Apparently the change occurred in just four days, a mere instant in the grand scheme of geological changes.

“Climate change is happening, is affecting us and it’s not just about far-off islands in the South Pacific,” Shugar told the CBC.  “The effects can be very rapid and can be somewhat unanticipated.”