Two lakes beneath the ice in Greenland, gone within weeks

January 21, 2015 by Pam Frost Gorder
In April 2014, researchers flew over a site in southwest Greenland to find that a sub-glacial lake had drained away. This photo shows the crater left behind, as well as a deep crack in the ice. Credit: Stephen Price, Los Alamos National Laboratory, courtesy of The Ohio State University.

Researchers who are building the highest-resolution map of the Greenland Ice Sheet to date have made a surprising discovery: two lakes of meltwater that pooled beneath the ice and rapidly drained away.

One once held billions of gallons of water and emptied to form a mile-wide crater in just a few weeks. The other lake has filled and emptied twice in the last two years.

Researchers at The Ohio State University published findings on each lake separately: the first in the open-access journal The Cryosphere and the second in the journal Nature.

Ian Howat, associate professor of earth sciences at Ohio State, leads the team that discovered the cratered lake described in The Cryosphere . To him, the find adds to a growing body of evidence that meltwater has started overflowing the ice sheet's natural plumbing system and is causing "blowouts" that simply drain lakes away.

"The fact that our lake appears to have been stable for at least several decades, and then drained in a matter of weeks—or less—after a few very hot summers, may signal a fundamental change happening in the ice sheet," Howat said.

The two-mile-wide lake described in Nature was discovered by a team led by researcher Michael Willis of Cornell University. Michael Bevis, Ohio Eminent Scholar in Geodynamics and professor of at Ohio State, is a co-author of the Nature paper, and he said that the repeated filling of that lake is worrisome.

Each time the lake fills, the meltwater carries stored heat, called latent heat, along with it, reducing the stiffness of the surrounding ice and making it more likely to flow out to sea, he said.

Bevis explained the long-term implications.

This is a map of a portion of southwest Greenland. The star marks the location of a drained subsurface lake discovered by Ian Howat of The Ohio State University and his team. Credit: Ian Howat, courtesy of The Ohio State University.

"If enough water is pouring down into the Greenland Ice Sheet for us to see the same sub-glacial lake empty and re-fill itself over and over, then there must be so much latent heat being released under the ice that we'd have to expect it to change the large-scale behavior of the ice sheet," he said.

Howat's team was first to detect the cratered lake described in The Cryosphere, on a spot about 50 kilometers (31 miles) inland from the southwest Greenland coast earlier in 2014. There, previous aerial and satellite imagery indicates that a sub-glacial lake pooled for more than 40 years. More recent images suggest that the lake likely emptied through a meltwater tunnel beneath the ice sheet some time in 2011.

The crater measures 2 kilometers (1.2 miles) across and around 70 meters (230 feet) deep. Researchers calculated that the lake that formed it likely contained some 6.7 billion gallons of water.

That's not a large lake by most reckoning, but it's roughly the same size as the combined reservoirs that supply water to the Columbus, Ohio metropolitan area's 1.9 million residents. And it disappeared in a single season—remarkably quickly by geologic standards. Howat characterized the sudden drainage as "catastrophic."

Researchers at The Ohio State University were creating the highest-resolution maps of the Greenland Ice Sheet made to date, when they discovered a crater, shown here, which had once been the site of a sub-glacial lake. Credit: Ian Howat, using a Worldview image copyright DigitalGlobe Inc.

Researchers suspect that, as more meltwater reaches the base of the ice sheet, natural drainage tunnels along the Greenland coast are cutting further inland, Howat explained. The tunnels carry heat and water to areas that were once frozen to the bedrock, potentially causing the ice to melt faster.

"Some independent work says that the drainage system has recently expanded to about 50 kilometers inland of the ice edge, which is exactly where this lake is," he added.

It's possible that the lake was tapped by one of the invading tunnels. It's also possible that thousands of such lakes dot the Greenland coast. They are hard to detect with radar, and researchers don't know enough about why and how they form. In contrast to Antarctica, researchers know much less about what's happening under the ice in Greenland.

"Until we get a good map of the bed topography where this lake was, we have no idea whatsoever how many lakes could be out there," Howat said. "There may be something really weird in the bed in this particular spot that caused water to accumulate. But, if all you need is a bumpy surface a bit inland from the coast, then there could be thousands of little lakes."

A 70 m deep basin formed near the summit of the Flade Isblink Ice Cap in the fall of 2012 when a lake 540 m beneath the ice surface suddenly emptied. Summer meltwater streams on the ice cap surface (blue) enter crevasses near the bottom of the image. Simulated 3-dimensional view from the south made using WorldView-2 Satellite imagery. Scale changes due to perspective, but the basin is about 4 km north-south and 2 km east-west. Credit: WorldView-2Imagery (c) 2014, DigitalGlobe, Inc.

Howat and his team flew over the site in southwest Greenland in April 2014, after they realized that detection of the crater, nestled in the midst of a flat ice expanse, was not just an error in the high-resolution surface data they've been collecting. Using European Space Imaging's Worldview satellites, they're assembling a Greenland ice map with 2-meter (approximately 6.5-feet) resolution.

Bevis and his colleagues discovered the lake described in Nature under similar circumstances in March 2013. They were gathering data to supplement their long-standing efforts to weigh the Greenland Ice Sheet with GPS and spotted the mitten-shaped lake by accident.

Using DigitalGlobe Inc.'s Worldview satellites and NASA's Operation IceBridge, the Cornell-led team calculated that the lake filled and emptied twice since 2012, at one point experiencing a sub-surface blowout that drove water from the lake at a volume of 215 cubic meters (nearly 57,000 gallons—close to the volume of a 30-foot-by-50-foot backyard swimming pool) every second.

Though researchers have long known of the existence of sub-glacial lakes, never before have they witnessed any draining away. The sudden discovery of two—one of which seems to be refilling and draining repeatedly—signals to Bevis that Greenland ice loss has likely reached a milestone.

"It's pretty telling that these two lakes were discovered back to back," he said. "We can actually see the pour down into these holes. We can actually watch these lakes drain out and fill up again in real time. With melting like that, even the deep interior of the is going to change."

Explore further: Greenland may be slip-sliding away due to surface lake melt: study

More information: Recharge of a subglacial lake by surface meltwater in northeast Greenland, Nature, DOI: 10.1038/nature14116

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18 comments

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verkle
Jan 21, 2015
This comment has been removed by a moderator.
OZGuy
4.7 / 5 (25) Jan 21, 2015
Excellent verkle, we'll get Greenland back but possibly lose most of the current arable land as temperatures rise. I'm sure glad you think that's good news.
artist1270
1 / 5 (16) Jan 21, 2015
Tell the air force to stop Geo-engineering, and tell DARPA to turn off the HAARP antennas in the Arctic. Problem solved.
You can't barbecue the atmosphere with ELF waves and expect good things to happen, duh.
earl_decker_33
1.3 / 5 (16) Jan 21, 2015
There is a lot researchers do not know about Greenland ice sheet and the undersurface lakes and how the subsurface melting has an impact on the ice sheet. The latest research by Denmark scientists say that the Greenland ice sheet is increasing in thickness and has been for the last 4 or so years. These same scientists say the sea ice in the Artic is also increasing opposite of all the previous models predictions for unexplained reasons. My overall assessment of the climate change is that the AGW scientists do not know diddly about climate change.
mooster75
4.7 / 5 (15) Jan 22, 2015
Tell the air force to stop Geo-engineering, and tell DARPA to turn off the HAARP antennas in the Arctic. Problem solved.
You can't barbecue the atmosphere with ELF waves and expect good things to happen, duh.

Nice hat. Tin?
mbee1
1.3 / 5 (15) Jan 22, 2015
there is only one thing wrong with this study, it is junk science at its worst. The ice melts on the surface each year, a portion of the water drains down into the ice each year hence the so called lakes which form and disappear as a channel needs to melt out to drain them which happens assuming water runs downhill and the glacier are higher than the sea. Since the arctic ice sheet was greater the last two years, last year greater in the atlantic than in the pacific it was colder not warmer which has actually occurred for several years as another paper points out the ice sheet is melting less than usual for four years as earl also notes. In november 2014 the Northern Hemisphere snow and ice cover was the 5th largest on record, North America the highest ever recorded. If anybody thinks that is not affecting Greenland they really need to take some prozac and see a shrink. IT IS COLDER NOT WARMER.
megmaltese
4 / 5 (8) Jan 22, 2015
Billions and billions of cubic meters of water going from ice caps to the seas every year.
THIS is keeping the global temperature low.
One this reserve of refrigeration will end, temperatures will abruptly rise.
Whydening Gyre
3.8 / 5 (5) Jan 22, 2015
For some reason, this makes me think of an igloo...
And how packed snow (ice) has an insulating property...
BrassOrchid
1 / 5 (12) Jan 22, 2015
Warm up the Arctic Sea so Greenland gets more snow in the winter. Problem solved.
omatwankr
4.4 / 5 (9) Jan 22, 2015
The latest research by Denmark scientists say that the Greenland ice sheet is increasing in thickness and has been for the last 4 or so years.


Confusion caused by anecdotes of structures being buried by accumulating snow on Greenland's ice sheet leads some skeptics to believe Greenland is Gaining Ice.
http://www.skepti...-ice.htm

scientists do not know diddly about climate change.


unless those scientists agree with your faith biased ill-informed and wrong world view.
omatwankr
4.6 / 5 (9) Jan 22, 2015
The latest research by Denmark scientists say that the Greenland ice sheet is increasing in thickness and has been for the last 4 or so years.


Confusion caused by anecdotes of structures being buried by accumulating snow on Greenland's ice sheet leads some skeptics to believe Greenland is Gaining Ice.
http://www.skepti...-ice.htm

scientists do not know diddly about climate change.


I think you mean:- scientist know diddily about climate change-? yours sound better with a southern drawl

unless those scientists agree with your faith biased ill-informed and wrong world view.
Whydening Gyre
4.3 / 5 (6) Jan 22, 2015
The latest research by Denmark scientists say that the Greenland ice sheet is increasing in thickness and has been for the last 4 or so years.


Confusion caused by anecdotes of structures being buried by accumulating snow on Greenland's ice sheet leads some skeptics to believe Greenland is Gaining Ice.
http://www.skepti...ice.htm.

Snow and ice being two completely different densities...
Captain Stumpy
4.6 / 5 (9) Jan 22, 2015
Since the arctic ice sheet was greater the last two years, last year greater in the atlantic than in the pacific it was colder not warmer which has actually occurred for several years
@mbee
first of all, you need to look at ALL the overall temps for a longer period than just a couple of years
take a look at this interesting video which takes the date from here: http://psc.apl.wa...anomaly/
This video https://www.youtu...youtu.be is a graphic reminder of the warming and the effects of the polar ice

and it should open your eyes... but only if you are willing to fact check it with the data posted at the first link, which also ties in with the recent studies being done

then you will see that not only are you wrong, but horribly wrong
Scroofinator
2.5 / 5 (4) Jan 22, 2015
If they found 2 lakes, how many do you think they missed? IMO there is no better explanation for the end of interglacials then these lakes (and massive icebergs) busting out and wreaking havoc on the AMOC.
rockwolf1000
5 / 5 (4) Jan 22, 2015
Billions and billions of cubic meters of water going from ice caps to the seas every year.
THIS is keeping the global temperature low.
One this reserve of refrigeration will end, temperatures will abruptly rise.


Could I re-word this a bit?

"Billions and billions of cubic meters of NEARLY FREEZING COLD water going from ice caps to the seas every year.
THIS is keeping the global temperature low."

sqorpo
4 / 5 (4) Jan 22, 2015
There is a lot researchers do not know about Greenland ice sheet and the undersurface lakes and how the subsurface melting has an impact on the ice sheet. The latest research by Denmark scientists say that the Greenland ice sheet is increasing in thickness and has been for the last 4 or so years. These same scientists say the sea ice in the Artic is also increasing opposite of all the previous models predictions for unexplained reasons. My overall assessment of the climate change is that the AGW scientists do not know diddly about climate change.

I think it is these "Denmark scientist" you are reading about who don't know diddly....
Whydening Gyre
3 / 5 (2) Jan 22, 2015

"Billions and billions of cubic meters of NEARLY FREEZING COLD water going from ice caps to the seas every year.
THIS is keeping the global temperature low."

I might add - for a while...
Whydening Gyre
1 / 5 (1) Jan 22, 2015
might I also add this little tidbit....
lower overall temps caused a reduction in humidity transferable to higher latitudes and thus a reduction in snowfall and eventually, ice. Once it warms slightly, humidification increases in higher lats and translates into more snow and eventually - more ice. It's a pretty neat self regulation system that cycles...

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