The lake is one of Yukon's largest, home to a handful of small communities, and its waters eventually feed into the mighty Yukon River.
So how the heck did it end up looking like this virtually overnight?
Image via Jim Best/University of Illinois.
It's supposed to be pristine and blue, not brown and full of weird, muddy goosebumps and dry, dusty mudflats.
This is a shocking case of what scientists call "river piracy." Something stole Kluane Lake's river.
The culprit wasn't a foul-mouthed, foul-smelling 17th-century sailor, though. The real culprit was — and is — much more creeping and insidious.
Kluane Lake used to get a big chunk of its water from the Slims River, which in turn was fed by the Kaskawulsh glacier. For years, the Slims River had been an ice-cold torrent of water up to 10 feet deep and too strong to wade through in some areas.
Over the course of four days in May 2016, though, river gauge data shows that all of that water just ... disappeared.
An aerial view of water being diverted from the Slims River. Image via Dan Shugar/University of Washington Tacoma.
Dan Shugar and Jim Best, scientists from the University of Washington and University of Illinois, went up to investigate in person. When they got there, they found a bare trickle of water where the river should have been.
"We were really surprised when we got there and there was basically no water in the river," Shugar said in an Associated Press report. "We could walk across it and we wouldn't get our shirts wet.”
They knew if something was stopping water from getting to the river, it must have happened uphill, likely at the mighty Kaskawulsh glacier that feeds the river.
When the scientists went to investigate, they found a massive 100-foot-tall ice canyon — a giant hole basically — inside the glacier's edge.
The ice-walled canyon. Image via Jim Best/University of Illinois.
It was the evidence they needed to identify the primary suspect behind the river's sudden vanishing act: climate change.
As the planet has gotten warmer, the Kaskawulsh glacier has been retreating and breaking up. For a long time, its meltwater had been going toward the Slims River.
When the river disappeared in May 2016, it was the result of the glacier having retreated enough that an ice wall collapsed, forming a canyon and diverting the meltwater down a different side of the mountain, away from the Slims River. Instead, the glacier's water rushed into the Alsek River, a phenomenon scientists call river piracy.
Satellite images taken one year apart show how much the river has fallen. Image via the European Space Agency.
River piracy hasn't been documented in modern times and certainly never this quickly. Shugar's team is more than 99% sure this wouldn't have happened without climate change.
Ever since, the Slims River has been a mere trickle and Kluane Lake has dropped more than 5 feet below average.
Shugar at Kluane Lake. Image via Jim Best/University of Illinois.
Kluane Lake is more than 45 miles long, so this isn’t a small amount of water we're talking about. The two communities on the lake will likely have to learn to deal with the water shortage because it’s virtually impossible that things will go back to the way they were.
Being witness to a case of river piracy is pretty incredible, but the speed at which it happened is a stark reminder that the effects of climate change can happen both slowly and all at once.
The Yukon is a pretty remote and sparsely populated area, but if a river disappeared in, say, the Andes or the Himalayas, it could affect the water supplies of millions of people, giving them little time to adapt to the change.
There are still plenty of things we can do to mollify the effects of climate change, but the first thing is to take it — and its causes — seriously and make sure the people in charge take it seriously too. Because if we don't, who knows where or when river piracy will strike again.
Đăng nhận xét