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

Apr 16, 2012
This is a surface or "supraglacial" lake on the Greenland Ice Sheet. Credit: Konrad Steffen, University of Colorado

Like snow sliding off a roof on a sunny day, the Greenland Ice Sheet may be sliding faster into the ocean due to massive releases of meltwater from surface lakes, according to a new study by the University of Colorado Boulder-based Cooperative Institute for Research in Environmental Sciences.

Such lake drainages may affect sea-level rise, with implications for , according to the researchers. "This is the first evidence that Greenland's 'supraglacial' lakes have responded to recent increases in surface meltwater production by draining more frequently, as opposed to growing in size," says CIRES research associate William Colgan, who co-led the new study with CU-Boulder computer science doctoral student Yu-Li Liang.

During summer, meltwater pools into lakes on the ice sheet's surface. When the gets high enough, the ice fractures beneath the lake, forming a vertical drainpipe, and "a huge burst of water quickly pulses through to the bed of the ice sheet," Colgan said.

The study is being published online today by the journal Remote Sensing of the Environment. The study was funded by the Arctic Sciences Program of the National Science Foundation.

The researchers used along with innovative feature-recognition software to monitor nearly 1,000 lakes on a Connecticut-sized portion of the ice sheet over a 10-year period. They discovered that as the climate warms, such catastrophic lake drainages are increasing in frequency. Catastrophic lake drainages were 3.5 times more likely to occur during the warmest years than the coldest years.

During a typical catastrophic lake drainage, about 1 million cubic meters of -- which is equivalent to the volume of about 4,000 Olympic -- funnels to the ice sheet's underside within a day or two. Once the water reaches the ice sheet's belly that abuts underlying rock, it may turn the ice-bed surface into a Slip 'N Slide, lubricating the ice sheet's glide into the ocean. This would accelerate the sea-level rise associated with climate change.

Alternatively, however, the lake drainages may carve out sub-glacial "sewers" to efficiently route water to the ocean. "This would drain the ice sheet's water, making less water available for ice-sheet sliding," Colgan said. That would slow the ice sheet's migration into the ocean and decelerate sea-level rise.

"Lake drainages are a wild card in terms of whether they enhance or decrease the ice sheet's slide," Colgan said. Finding out which scenario is correct is a pressing question for climate models and for communities preparing for sea-level change, he said.

For the study, the researchers developed new feature-recognition software capable of identifying supraglacial lakes in satellite images and determining their size and when they appear and disappear. "Previously, much of this had to be double-checked manually," Colgan said. "Now we feed the images into the code, and the program can recognize whether a feature is a lake or not, with high confidence and no manual intervention."

Automating the process was vital since the study looked at more than 9,000 images. The researchers verified the program's accuracy by manually looking at about 30 percent of the images over 30 percent of the study area. They found that the algorithm -- a step-by-step procedure for calculations -- correctly detected and tracked 99 percent of supraglacial lakes.

The program could be useful in future studies to determine how lake drainages affect sea-level rise, according to the researchers. CIRES co-authors on the team include Konrad Steffen, Waleed Abdalati, Julienne Stroeve and Nicolas Bayou.

Explore further: Synchronization of North Atlantic, North Pacific preceded abrupt warming, end of ice age

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NotParker
1.4 / 5 (19) Apr 16, 2012
The "belly" of the ice sheets is below sea level already. Don't they know even the most basic fact?

"catastrophic lake drainage" -- a new catchphrase created by a secret committee of idiots who belong to the IPCC cabal.

"In Greenland, the survey saw large ice losses along the southeastern coast and a large increase in ice thickness at higher elevations in the interior due to relatively high rates of snowfall. This study suggests there was a slight gain in the total mass of frozen water in the ice sheet over the decade studied, contrary to previous assessments."

Ice melts in the summer. It snows the rest of the time creating more ice.

Vendicar_Decarian
0.8 / 5 (44) Apr 16, 2012
Kook Tarrrrrrrrrrrrrrrrd

""catastrophic lake drainage" -- a new catchphrase created by a secret committee of idiots who belong to the IPCC cabal." - Parker Tard

You need to see a psychiatrist ParkerTard. You are clearly mentally ill.

"Ice melts in the summer." - ParkerTard

Greenland Ice Mass Balance

http://www.skepti...Mass.gif
rikvanriel
1.6 / 5 (13) Apr 16, 2012
The "belly" of the ice sheets is below sea level already. Don't they know even the most basic fact?


Good point. It will take more than reduced friction for the ice to slide up over the mountains and into the sea.
NotParker
1.8 / 5 (15) Apr 16, 2012
NASA: From 1992 to 2002: "The Greenland ice sheet annually gained approximately 11 billion tons of water"

Hmmm. Didn't AGW cult members claim the earth was warming?

Why does VD's source use only 6 years of data? Why not the previous 10 years?

Why hide the incline in ice.

rikvanriel
1.7 / 5 (12) Apr 16, 2012
Greenland's ice mass grows in years with lots of precipitation and declines in years of draught. Airplanes that crashed on Greenland during WWII are now covered under a few meters of ice.
MikPetter
3.7 / 5 (9) Apr 16, 2012
Extract from "Recent contributions of glaciers and ice caps to sea level rise"
Nature 482, 514518 (23 February 2012)

The CU-led team also used GRACE data to calculate that the ice loss from both Greenland and Antarctica,
including their peripheral ice caps and glaciers, was roughly 385 billion tons of ice annually.
The total mass ice loss from Greenland, Antarctica and all Earth's glaciers and ice caps from
2003 to 2010 was about 1,000 cubic miles, about eight times the water volume of Lake Erie, said Wahr.

"The total amount of ice lost to Earth's oceans from 2003 to 2010 would cover the entire
United States in about 1 and one-half feet of water," said Wahr, also a fellow at the
CU-headquartered Cooperative Institute for Research in Environmental Sciences.
ccr5Delta32
4.2 / 5 (6) Apr 16, 2012
@NotParker
"catastrophic lake drainage" -- a new catchphrase created by a secret committee of idiots who belong to the IPCC cabal.


Catastrophic : catastrophe theory is a branch of bifurcation theory
http://en.wikiped...e_theory
To get you started
rikvanriel
1.9 / 5 (9) Apr 16, 2012
The total mass ice loss from Greenland, Antarctica and all Earth's glaciers and ice caps from 2003 to 2010 was about 1,000 cubic miles, about eight times the water volume of Lake Erie, said Wahr.


Which sounds like a lot, until you look up just how much ice there is in Greenland and Antarctica. Antarctica has over 5 million cubic miles of ice and Greenland over 700,000 cubic miles. All other glaciers and ice sheets add up to about 43,000 cubic miles.
Lurker2358
3.7 / 5 (7) Apr 16, 2012
The "belly" of the ice sheets is below sea level already. Don't they know even the most basic fact?


As ice melts off the island the land will rebound and the elevation will increase in the interior, at a ratio of somewhere between 2.5 and 5 to 1 ice thickness lost vs crustal rebound, it depends on rock types in the crust.

We already discussed this with you on other threads.

===

What do you say about the fact that weather stations and research stations in Greenland, Iceland, and Svalbard show that the mean temperature in those locations is rising tremendously compard to historical norms? It's up to a mean of like 6C above the historical norms already, and a lot more than that on extreme days.

What do you say to that?

I suppose you'll blame the instruments or some natural cycle, etc.
NotParker
1.4 / 5 (10) Apr 16, 2012
As ice melts off the island the land will rebound and the elevation will increase in the interior, at a ratio of somewhere between 2.5 and 5 to 1 ice thickness lost vs crustal rebound, it depends on rock types in the crust.


Over thousands of years. Sweden is still rebounding from the last ice age.

What do you say about the fact that weather stations and research stations in Greenland, Iceland, and Svalbard show that the mean temperature in those locations is rising tremendously compard to historical norms?


Most of them show 1920s/30s/40s was pretty warm.

http://data.giss....ghbors=1

http://data.giss....ghbors=1

http://data.giss....ghbors=1

NotParker
1.4 / 5 (10) Apr 16, 2012
The total amount of ice lost to Earth's oceans from 2003 to 2010 would cover the entire
United States in about 1 and one-half feet of water,"


"Antarctica is about 4.5 million square miles (14 million square kilometers) in area, which is about the size of the contiguous 48 U.S. states plus about half of Mexico"

"At its thickest point the ice sheet is 15,669 feet (4,776 meters) deep."

A teensy, tiny bit thicker than 1.5 feet don't you think?
Lurker2358
3.3 / 5 (7) Apr 16, 2012
Most of them show 1920s/30s/40s was pretty warm.

http://data.giss....ghbors=1


You realize in the past many weather standards were not yet established, and temperatures were often taken in the direct exposure to sunlight?

In modern times, temperatures are taken in a heavily shaded system so as to get the air temperature rather than the radiant temperature from the Sun.

It's an important issue, because if anything, old day time high temperature records were over-estimating the temperature.

What's even more astonishing is that the record high temperatures in recent decades are taken in the shade and still beat the old record highs from the 1800's and early 1900's, which were often taken in sunlight.
NotParker
1.4 / 5 (10) Apr 16, 2012
The thermometers were shaded by a Stevenson Screen (invented 1800s)

"A meteorologist reading a thermometer on a Stevenson Screen, Greenland, 1935-36"

http://www.bridge...-Stevens
NotParker
1.4 / 5 (10) Apr 16, 2012

In modern times, temperatures are taken in a heavily shaded system so as to get the air temperature rather than the radiant temperature from the Sun.


In the US, they called Stevenson Screens "Cotton Regional Shelters".

In 1907 they started using them in Las Vegas (as example of why you are totally full of crap).

"Weather instruments consisted of a standard rain gauge and
maximum and minimum thermometers housed in a cotton region shelter at an elevation of 2033 feet with good exposure at a site just across the railroad tracks from the depot. Observations here began on August 1, 1907"

http://www.wrh.no...tory.pdf
NotParker
1.4 / 5 (10) Apr 16, 2012
Cotton Regional Shelters were introduced in 1883.

"By 1903, 77.7% of all stations used free-standing screens, and 14.5% used north wall screens; the remaining stations (7.8%) did not use a screen."

http://journals.a...0.CO%3B2
A2G
1.4 / 5 (7) Apr 16, 2012
VD as soon as I see your immature "tard" comment I quit reading..

F***ing grow up
Vendicar_Decarian
0.7 / 5 (40) Apr 16, 2012
Greater precipitation was the cause.

"NASA: From 1992 to 2002: "The Greenland ice sheet annually gained approximately 11 billion tons of water"" - Parker Tard

Meanwhile the massive ice loss in greenland continues.

http://www.skepti...ance.gif

Greenland mass balance and its components Surface Mass Balance (SMB) and Discharge (D).

Vendicar_Decarian
0.5 / 5 (39) Apr 16, 2012
Tards are as Tards do.

"VD as soon as I see your immature "tard" comment I quit reading.." - A2gTard
Vendicar_Decarian
0.4 / 5 (37) Apr 16, 2012
And getting smaller by the day.

"Antarctica is about 4.5 million square miles (14 million square kilometers) in area, which is about the size of the contiguous 48 U.S. states plus about half of Mexico"" - ParkerTard
Vendicar_Decarian
0.4 / 5 (37) Apr 16, 2012
So you say, but the earth has been cooling for the last 12,000 years since the peak at the end of the last ice age.

"Sweden is still rebounding from the last ice age." - Parkertard

Your plot shows Akureyri warming at a rate of 1.5'C over the last 130 years.

Extrapolated backward from to the start of the last interglacial, that trend would put global temperatures 12,000 years ago at 138'C lower than today.

The warming trend of the last 180 years is very steep compared to the historical record with the trend accelerating as solar output has declined.

Poor ParkerTard. Not even his own data agrees with his own assertions.

Mental illness is like that.
Vendicar_Decarian
0.6 / 5 (39) Apr 17, 2012
Oh, that is easy. ParkerTard is a congenital and perpetual liar.

He will say anything to defend his failed Conservative Ideology.

"What do you say about the fact that weather stations and research stations in Greenland, Iceland, and Svalbard show that the mean temperature in those locations is rising tremendously compard to historical norms?" - Lurker
NotParker
1.4 / 5 (9) Apr 17, 2012

Your plot shows Akureyri warming ...


... longer, faster from 1895 to 1940. Natural cycle.

As I've said, the 1920s/30s/40s were just as warm in Greenland as today.

Nothing to do with CO2.

rubberman
4 / 5 (4) Apr 17, 2012
IF our current warming has nothing to do with CO2, please explain why the degree of measured warming is currently so much larger in the arctic....please.
NotParker
1.6 / 5 (7) Apr 17, 2012
IF our current warming has nothing to do with CO2, please explain why the degree of measured warming is currently so much larger in the arctic....please.


What warming?

http://www.real-s...e-arctic

The world is .8C colder than 1998.

http://www.real-s...0-so-far
rubberman
4 / 5 (4) Apr 17, 2012
Rather than link any of the hundreds of legitimate sources that have measured temperature increases across the arctic (globe) for the last 30 years to refute your link to Stephen Goddards personal opinion page on why temperatures haven't increased, I'll just assume that as usual, you forgot to take your meds and are having trouble comprehending your surroundings, forgot that you turned up the air conditioner and therefore now think the climate is cooling....bundle up!
Lurker2358
4 / 5 (4) Apr 17, 2012

What warming?

http://www.real-s...e-arctic


March 2012 was the 16th warmest March on record based on global air temperatures and Sea Surface temperatures. However, that does not take into account the enormous amounts of loss in ice volume over the past 10 years and the heat of fusion which that represents, nor does it take into account that the deep oceans in and around the Arctic and Antarctic circles have been increasing by 0.2 to 0.3C per decade, on average, from TOP TO BOTTOM.

Compared to that, the top 1 meter surface temperatures are meaningless, and are heavily influenced by wind direction and convection.

The average temperatures of the entire water columns are increasing at an obscene rate, which is actually greater than the 2 watts per meter forcing calculations.
kaasinees
0.7 / 5 (26) Apr 17, 2012
I told you before parkertard.
The massive melting of greenland, russian, artic etc. ice is slowing down the warming of the ocean, thus also land, and can also effectively cause a temporary anamoly of cooling, while in fact the globe is warming.
I know this is hard to understand for a tard like you.
NotParker
1 / 5 (9) Apr 17, 2012

March 2012 was the 16th warmest March on record


Out of 34.

RSS Globally has March at .075C.

1988 was warmer. 1990 was warmer 1991 was warmer .... etc

http://www.remss....03_3.txt

NotParker
1 / 5 (8) Apr 17, 2012
I told you before genius.
The massive melting of greenland, russian, artic etc. ice ...


... is not happening.

Ice is above normal. Your scare stories would work better if you weren't telling obvious checkable lies.

NotParker
1 / 5 (9) Apr 17, 2012
Lurker:
You realize in the past many weather standards were not yet established, and temperatures were often taken in the direct exposure to sunlight?


When will you apologize for such an ignorant fabrication?
kaasinees
0.8 / 5 (25) Apr 17, 2012

... is not happening.

Ice is above normal. Your scare stories would work better if you weren't telling obvious checkable lies.



idiot.

http://en.wikiped...dia_.jpg

http://en.wikiped...ange.png
Lurker2358
4 / 5 (4) Apr 17, 2012
Lurker:
You realize in the past many weather standards were not yet established, and temperatures were often taken in the direct exposure to sunlight?


When will you apologize for such an ignorant fabrication?


That is NOT a fabrication, and is the reason records from before 1880 are never used as a scientific resource in weather or climatology, even where they happen to exist.

Many stations do not even have reliable records that far back, even in the U.S.
Lurker2358
4 / 5 (4) Apr 17, 2012

Out of 34.

RSS Globally has March at .075C.

1988 was warmer. 1990 was warmer 1991 was warmer .... etc

http://www.remss....03_3.txt



No, out of 118, actually.

February was the globes 22nd warmest, and march was the 16th warmest.

That doesn't mean the planet is cooling.

It is interesting to note that NONE of the coolest 50% of years occurred in the past 30 years.

http://en.wikiped...lies.png

Every year since 1997 has been hotter than any year prior to 1997, with the exception of 2000.

The only year prior to 1997 which was hotter than 2000 is 1995.

Using 1971 to 2011, 41 years, the 16 hottest years all occurred in the last 17 years.

Further, of all the years hotter than 1996 or tied with it, only 3 of them occurred before 1990, the mid-way point in the sample. The other 19 have occurred since 1990.
Bitflux
5 / 5 (6) Apr 17, 2012
Greenland's ice mass grows in years with lots of precipitation and declines in years of draught. Airplanes that crashed on Greenland during WWII are now covered under a few meters of ice.


No in fact theyre not. Take trip to the ice in Kangerlussuaq and you will se the airplanes lying beside the road, exactly as they crashed. Oh and by the way, ive been travelling to and in Greenland for the last 1o years. The ice has retracted several kilometers inland. In fact much of northern Greenland is a cold desert - very dry. You should all try and go there sometime and see things with your own eyes.
NotParker
1 / 5 (9) Apr 17, 2012
No, out of 118, actually.


Who says?
NotParker
1 / 5 (8) Apr 17, 2012
Take trip to the ice in Kangerlussuaq


At the end of a fjord it is at sea level. And it snows very little, unlike higher up and inland.

rubberman
3.7 / 5 (6) Apr 17, 2012
Take trip to the ice in Kangerlussuaq


At the end of a fjord it is at sea level. And it snows very little, unlike higher up and inland.



So you have pictures from YOUR last trip?

NotParker
1 / 5 (7) Apr 17, 2012

So you have pictures from YOUR last trip?


Google Has pictures. You definitely never google. Your info sucks.
NotParker
1 / 5 (7) Apr 17, 2012
"At each stop, Morris will
spend several hours using an approximately
5-centimeter-
diameter
auger (like a giant
corkscrew, she said) to drill 10 meters into
the snow for a neutron scattering probe to
take measurements of the snow every centimeter.
As fast neutrons from the probe
collide with hydrogen atoms in the snow,
the neutrons lose energy and come back
as slow neutrons that can be counted, she
explained. By counting the slow neutrons,
the density of the snow can be determined,
she said. With those 10 meters, which represent
about 25 years of snow accumulation"

That was near Summit Greenland.

Looks a bit cold:

http://www.summit.../webcam/
rubberman
4.2 / 5 (5) Apr 17, 2012
So your point is that it is cold and the snow/ice is deep at Summit station, Greenland....well done! Do you have any other revelations you can share with us? Perhaps the noon temperature and soil conditions in the middle of the Sahara...bet it's hot and sandy! Of course Bitflux wasn't talking about either now was he? Good picture of Summit station, never would have expected there to be that much snow and ice in the winter at the apex of a country sized Glacier....that hasn't melted yet.
NotParker
1 / 5 (7) Apr 17, 2012

That is NOT a fabrication, and is the reason records from before 1880 are never used as a scientific resource in weather or climatology, even where they happen to exist.

Many stations do not even have reliable records that far back, even in the U.S.


By 1903 over 90% of US stations had some sort of screen.

I do acknowledge that present temperatures are crap.

"Some examples include weather stations placed near sewage treatment plants, parking lots, and near cars, buildings and air-conditioners - all artificial heat sources which could affect temperature records."

http://newsbuster...idelines

Lurker2358
3.7 / 5 (3) Apr 21, 2012
No, out of 118, actually.


Who says?


NOAA and Dr. Jeff Masters on Wunderground dot com.

Every month they put out a map of the U.S. and the globe ranking it on a scale from 1 to whatever year the data goes.

So you see, many states in the U.S. had their hottest March on record, and in fact, this March was above the long term average by amount making it the second highest deviation on record for any month in any year. The only higher month was in 2006.

But one should also note that the past 25 years have been so hot they they are starting to weight the long term average upwards.

Also, on 30 year averages, the updated 30 year normal from 1981 to 2010 is significantly warmer on average than the old 30 year normal from 1971 to 2000, because 10 of the 15 hottest years on record happened from 2001 to 2010.
NotParker
1 / 5 (7) Apr 21, 2012

NOAA and Dr. Jeff Masters on Wunderground dot com.


Did they tell you:

According to the NOAA, in the Pacific Northwest, 2011 was the 31st coldest year out of the last 117.

2010 was the 92nd coldest.

2009 was the 67th coldest.

2008 was the 47th coldest.

1934 is still the warmest.

1898 was warmer than 2011.
NotParker
1 / 5 (7) Apr 21, 2012
Which year had the previous record for warmest March in the US?

1910
NotParker
1 / 5 (7) Apr 21, 2012
Which year had the previous record for warmest March in the US?

1910


February 2012 was 3.93F colder than 1954.