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THE Glacier Thread (merged)

Re: THE Glacier Thread (merged)

Unread postby Subjectivist » Sun 01 Jan 2017, 15:49:51

It isn't easy to say why a glacier might retreat or whether that retreat is a product of global warming. But a team led by Gerard Roe of the University of Washington in Seattle has found a way to look at the big picture.

The scientists studied the pattern of behavior of 37 glaciers spread around the globe, in Austria, in Washington State in the U.S., in New Zealand, in Sweden and so on, and matched them with local meteorological trends.

Ideally, researchers would like to know about the changes in the mass of ice in a glacier, but measurements of these don't stretch very far back. But the retreat of the world's glaciers—their terminals now compared with where they ended many decades ago—is well documented in paintings, photographs and alpine records.

http://www.ecowatch.com/climate-change- ... 10674.html
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Re: THE Glacier Thread (merged)

Unread postby WildRose » Tue 03 Jan 2017, 02:38:23

I found this article about a recent (last month) climbing expedition into Athabasca Glacier in Jasper National Park. Will Gadd and his team are attempting to learn how climate change is affecting glaciers from within. Some interesting findings:

“The interesting thing was the moulin was packed with snow so the first thing we had to do was this kind of tunneling exercise for about 10 metres vertically, but what was weird was that there was this warm air coming up,” said Gadd.

“It was a difficult situation to dig that much snow to get where we wanted to go, but we got through it by following the warm air, which was odd,” said Gadd.

“Why would there be warm air coming out of a glacier?”



“There was liquid water in there, in the middle of winter at -30,” said Gadd, explaining the temperature reached a balmy three degrees Celsius.

“How is this possible? We were all kind of at a kind of loss.”



That wasn’t the only thing that surprised the group. The next thing they found was a form of algae.

“These biofilms have apparently not been seen below the surface of a glacier before either, so we need to go back and get samples of these biofilms and work with Parks to get permission to do that.”



And he describes the retreat of the Athabasca Glacier, saying that we're all familiar with what the retreat of the glacier looks like, but it's actually the vertical loss of ice that is the most amazing:

“It’s retreated massively since when I was a kid,” said Gadd. “I think everybody sees the glacier recession and that’s a big deal, but one of the things that I learned on this trip that surprised me, is that it’s actually the vertical loss that’s greater than the horizontal loss.”

“It’s not as obvious, but if you look along the sides of the Athabasca Glacier you can see it’s lost probably 100 metres or more of ice and if you think about that it’s like going from a very, very thick block of ice down to a relatively thin skating rink,” said Gadd.



http://www.fitzhugh.ca/ice-climber-expl ... a-glacier/
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Re: THE Glacier Thread (merged)

Unread postby Tanada » Tue 03 Jan 2017, 03:12:11

Water has an astounding heat capacity. When they get ready to open the Sault Ste. Marie canal locks between Lake Superior and Lake Huron they just turn on a circulating pump in each lock chamber. As the bottom water at about 3 C gets pumped out on the surface of the ice it erodes the solid surface into liquid with no need to add expensive heating. They have used this method for a very very long time each spring. The water column is only about 55 feet, but that volume has enough stored thermal energy to melt a meter of surface ice when daytime air temperatures are barely above freezing for a few hours a day.
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Re: THE Glacier Thread (merged)

Unread postby dohboi » Wed 04 Jan 2017, 18:31:40

"Water has an astounding heat capacity"

Exactly. That's why it's so amazing and frightening that we are actually warming up, not just the atmosphere and the surface of the earth, but the vast deep oceans. Boggles the mind, really.
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Re: THE Glacier Thread (merged)

Unread postby kiwichick » Thu 05 Jan 2017, 03:16:07

+ 1 d ...without the oceans we would have already heated up the planet by approx. 30 degrees C

this years arctic melt season could be very interesting
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Re: Climate Chaos Is Here Pt. 3

Unread postby dohboi » Mon 17 Apr 2017, 11:56:30

Those look interesting. Thanks, vox.

Meanwhile, more chaos:

Climate Change Reroutes a Yukon River in a Geological Instant

In the blink of a geological eye, climate change has helped reverse the flow of water melting from a glacier in Canada’s Yukon, a hijacking that scientists call “river piracy.”

This engaging term refers to one river capturing and diverting the flow of another. It occurred last spring at the Kaskawulsh Glacier, one of Canada’s largest, with a suddenness that startled scientists.

Much of the meltwater from the glacier normally flows to the north into the Bering Sea via the Slims and Yukon Rivers. A rapidly retreating and thinning glacier — accelerated by global warming — caused the water to redirect to the south, and into the Pacific Ocean.


https://mobile.nytimes.com/2017/04/17/s ... river.html
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Re: Climate Chaos Is Here Pt. 3

Unread postby dissident » Mon 17 Apr 2017, 14:57:07

dohboi wrote:Those look interesting. Thanks, vox.

Meanwhile, more chaos:

Climate Change Reroutes a Yukon River in a Geological Instant

In the blink of a geological eye, climate change has helped reverse the flow of water melting from a glacier in Canada’s Yukon, a hijacking that scientists call “river piracy.”

This engaging term refers to one river capturing and diverting the flow of another. It occurred last spring at the Kaskawulsh Glacier, one of Canada’s largest, with a suddenness that startled scientists.

Much of the meltwater from the glacier normally flows to the north into the Bering Sea via the Slims and Yukon Rivers. A rapidly retreating and thinning glacier — accelerated by global warming — caused the water to redirect to the south, and into the Pacific Ocean.


https://mobile.nytimes.com/2017/04/17/s ... river.html


Yes, one more nail in the coffin of a cold Arctic Ocean. Even if this fresh water flux is a small part of the total amount, it will contribute to increasing surface water salinity.
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Re: Climate Chaos Is Here Pt. 3

Unread postby dohboi » Mon 17 Apr 2017, 17:31:43

I hadn't thought about that feedback, dis.

And I think you're right about shifting goal posts. But that's the nature of these articles these days.

Squil would be right if it were just about ice cover, perhaps. But there are good proxies for global temps going back that far, I think.
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Re: THE Glacier Thread (merged)

Unread postby WildRose » Mon 17 Apr 2017, 19:24:43

Check this out. This happened in the Yukon in the summer of 2016. Evidence of modern climate change, "an event not documented in modern times" called "river piracy", which occurs when glacier meltwater changes its direction of flow due to severe geological event, in this case, rapid climate change:

http://www.cbc.ca/news/technology/clima ... -1.4070153

Shugar and colleague James Best, a professor of geology and geography from the University of Illinois, travelled to the Slims River in the Kluane National Park and Reserve west of Haines Junction, Yukon, last summer. It was his first summer as a professor, and Shugar had a grant to study changes to the flow of the Slims.

Retreating Yukon glacier makes river disappear

"We went there anticipating low flow and it turned out to be no flow," said Shugar.

Best said the change compared to their previous visit was "absolutely astonishing."



It looks like this happened much sooner than expected:

Their colleague and co-author John Clague had speculated in a 2006 study that the Slims River would eventually disappear, but none of them predicted the timeframe.

River gauges show there was an abrupt drop in the water level in just four days between May 26 and May 29, 2016.
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Re: THE Glacier Thread (merged)

Unread postby Tanada » Tue 18 Apr 2017, 06:19:20

A more accessible article about the river course change you all are chatting about, with several pictures worth viewing.

The massive Kaskawulsh Glacier in northern Canada has retreated about a mile up its valley over the past century.

This canyon now carries almost all meltwater from the toe of the glacier down the Kaskawulsh Valley and toward the Gulf of Alaska.Jim Best/University of Illinois

Last spring, its retreat triggered a geologic event at relatively breakneck speed. The toe of ice that was sending meltwater toward the Slims River and then north to the Bering Sea retreated so far that the water changed course, joining the Kaskawulsh River and flowing south toward the Gulf of Alaska.

This capture of one river’s flow by another, documented in a study led by the University of Washington Tacoma and published April 17 in Nature Geoscience, is the first known case of “river piracy” in modern times.

“Geologists have seen river piracy, but nobody to our knowledge has documented it happening in our lifetimes,” said lead author Dan Shugar, a geoscientist at the University of Washington Tacoma. “People had looked at the geological record — thousands or millions of years ago — not the 21st century, where it’s happening under our noses.”

River piracy, also known as stream capture, can happen due to tectonic motion of Earth’s crust, landslides, erosion or, in this case, a change in a glacial dam. The new study documents one of the less-anticipated shifts that can occur in a changing climate.

Shugar and co-authors Jim Best at the University of Illinois and John Clague at Canada’s Simon Fraser University had planned fieldwork last summer on the Slims River, a geologically active system that feeds Kluane Lake in the Yukon. When they arrived in August, the river was not flowing. River gauges show an abrupt drop over four days from May 26 to 29, 2016.

By late summer, “there was barely any flow whatsoever. It was essentially a long, skinny lake,” Shugar said. “The water was somewhat treacherous to approach, because you’re walking on these old river sediments that were really goopy and would suck you in. And day by day we could see the water level dropping.”

The research team puzzled about what to do next. They got permission to use their mapping drone to create a detailed elevation model of the glacier tongue and headwater region. The resulting paper is a geological postmortem of the river’s disappearance.

“For the last 300 years, Slims River flowed out to the Bering Sea, and the smaller Kaskawulsh River flowed to the Gulf of Alaska. What we found was the glacial lake that fed Slims River had actually changed its outlet,” Shugar said. “A 30-meter (100-foot) canyon had been carved through the terminus of the glacier. Meltwater was flowing through that canyon from one lake into another glacial lake, almost like when you see champagne poured into glasses that are stacked in a pyramid.”

That second lake drains via the Kaskawulsh River in a different direction than the first. The situation is fairly unique, Shugar said, since the glacier’s toe was sitting on a geologic divide.

Clague began studying this glacier years ago for the Geological Survey of Canada. He observed that Kluane Lake, which is Yukon’s largest lake, had changed its water level by about 40 feet (12 meters) a few centuries ago. He concluded that the Slims River that feeds it had appeared as the glacier advanced, and a decade ago predicted the river would disappear again as the glacier retreated.

“The event is a bit idiosyncratic, given the peculiar geographic situation in which it happened, but in a broader sense it highlights the huge changes that glaciers are undergoing around the world due to climate change,” Clague said.

Less input from the Slims River has lowered the water level of Kluane Lake, the largest lake in the Yukon, exposing sediments and creating dust storms.

The geologic event has redrawn the local landscape. Slims River crosses the Alaska Highway, and its banks were a popular hiking route. Now that the riverbed is exposed, Dall sheep from Kluane National Park are making their way down to eat the fresh vegetation, venturing into territory where they can legally be hunted. With less water flowing in, Kluane Lake did not refill last spring, and by summer 2016 was about 3 feet (1 meter) lower than ever recorded for that time of year. Waterfront land, which includes the small communities of Burwash Landing and Destruction Bay, is now farther from shore. As the lake level continues to drop researchers expect this will become an isolated lake cut off from any outflow.

On the other hand, the Alsek River, a popular whitewater rafting river that is a UNESCO world heritage site, was running higher last summer due to the addition of the Slims River’s water.

Shifts in sediment transport, lake chemistry, fish populations, wildlife behavior and other factors will continue to occur as the ecosystem adjusts to the new reality, Shugar said.

“So far, a lot of the scientific work surrounding glaciers and climate change has been focused on sea-level rise,” Shugar said. “Our study shows there may be other underappreciated, unanticipated effects of glacial retreat.”

The Kaskawulsh Glacier is retreating up the valley because of both readjustment after a cold period centuries ago, known as the Little Ice Age, and warming due to greenhouse gases. A technique published in 2016 by UW co-author Gerard Roe shows a 99.5 percent probability that this glacier’s retreat is showing the effects of modern climate change.

“I always point out to climate-change skeptics that Earth’s glaciers are becoming markedly smaller, and that can only happen in a warming climate,” Clague said.

Other co-authors are Christian Schoof at the University of British Columbia, Michael Willis at the University of Colorado and Luke Copland at the University of Ottawa. The study was funded by the University of Washington Royalty Research Fund, Parks Canada, Yukon Geological Survey, the Natural Sciences and Engineering Research Council of Canada, the University of Ottawa and the University of Illinois.


http://www.washington.edu/news/2017/04/ ... disappear/
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