Sunday, April 23, 2017

21 April 2017
By David Suzuki

Looking up (click here) the Slims River Valley, from the south end of Kluane Lake. The river used to flow down the valley from the Kaskawulsh glacier.

The Slims river in northern Canada gained infamy, (click here) not for its fishing or pristine waters, but for vanishing in a matter of four days in May 2016. This week we learned that it fell victim to “river piracy” – and climate change was almost certainly to blame.
The river – which stretched up to 150 meters at its widest points and averaged depths around three meters – lost its water source to another nearby river during a period of intense melting affecting one of Canada’s largest glaciers. As a result, the Slims was reduced to a trickle in less than a week.
We can now add river piracy to the growing list of unexpected, dramatic and tragic consequences of human-caused climate change. Although this is the first observed case of river piracy, it likely won’t be the last.
The melting of Yukon’s massive Kaskawulsh glacier – known to the local Southern Tutchone First Nation as Tänshī – caused the drainage gradient to tip in favour of the second river, redirecting the meltwater to the Gulf of Alaska, thousands of miles from its original destination.
The science says there’s a 99.5% chance that climate change caused this dramatic transformation of the landscape. The continuing warming trend that caused the glacier to thin so extremely means the change is likely irreversible....
Melt water from the Kaskawulsh glacier now flows down the Kaskawulsh River toward the Pacific, instead of northward to the Bering Sea via Kluane Lake.