Satellites reveal rare levels of Greenland ice melt
Satellite data show Greenland surface melt on July 8, left, and July 12. "Melt" is dark pink; "probable melt" is light pink.
July 25th, 2012
12:40 PM ET

Satellites reveal rare levels of Greenland ice melt

Nearly all of Greenland’s ice cover at least temporarily melted at the surface during an unusually warm stretch in mid-July - a level of melting not seen there in 123 years, NASA said.

In an average summer, melting happens on about half of the surface of Greenland’s ice sheet, which covers most of the land and is an average 1 mile thick.

But an unusually strong ridge of relatively warm air - hovering just above freezing for several hours at the highest elevation - rapidly accelerated melting this month, and satellites showed that an estimated 97% of the surface had melted at some point by July 12, NASA said.

While some of that melt water freezes in place, some of it is lost to rivers and the ocean – and mid-July’s melting caused river flooding that threatened a number of bridges, said Tom Wagner, NASA’s cryosphere program manager in Washington. (The flooding has been captured on a number of YouTube videos, including this one.)

Where this falls in the larger context of Greenland’s changing ice cap - scientists say it is shrinking and causing ocean levels to rise, with warming ocean waters causing ice on the periphery to be lost through melting and rapid flow - is a complicated question, NASA says.

Ice core samples show that the surface melting seen this July happens once in about every 150 years, and the last such melt happened in 1889, NASA said.

“It could be that this melt event is caused by normal variations that just happen once in a while,” Wagner said by phone Tuesday.

So, Wagner said, one can’t attribute July’s melting to global warming, but the melting must be digested with this in mind: that "warming is causing the loss of ice all over Greenland, and the Greenland ice sheet is shrinking."

Wagner said Greenland has lost 150 gigatons of ice per year over the last 20 years, and its shrinking cap contributes up to half a millimeter a year to global sea-level rise. Researchers haven’t determined how much of mid-July’s melt refroze or went into the ocean, NASA said.

The July 8-12 melting happened days before an island of ice twice the size of Manhattan broke off from Greenland’s Petermann Glacier on July 16. But with glacier calving attributed to ocean temperature, not the more quickly fluctuating air temperature, no one is linking the calving to July’s melting of surface ice, Wagner said.

July’s melting "combined with other natural but uncommon phenomena, such as the large calving event last week on Petermann Glacier, are part of a complex story,” Wagner said in a news release. “Satellite observations are helping us understand how events like these may relate to one another as well as to the broader climate system.”

July’s melting was detected by three satellites - the Indian Space Research Organization’s Oceansat-2, and NASA’s Terra and Aqua.

July 18, 2012: Massive ice island breaks off Greenland glacier

May 4, 2012: Greenland ice melt could raise seas less than feared, study says

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Filed under: Greenland • Science • Weather
soundoff (263 Responses)
  1. Greek American

    Sarah Palin said she could see the Greenland ice melting from looking out the window of her home.

    July 25, 2012 at 6:37 pm | Report abuse |
  2. Josh

    QUICK! CALL IT ICELAND! oh. wait.

    July 25, 2012 at 6:39 pm | Report abuse |
  3. FloridaBill

    Well on the one hand the do say it happened before in the 1880s (probably at the height of the coal powered early industrial revolution I note),but on the other hand if you read this in context of large melts at the Arctic and Antarctic, unusually strong storms in the US (including something new to me the Derecha), already reported rising ocean levels and a report that the mean sea level between Cape Hatteras and Cape Cod will be higher than anticipated because of a slowing of the Gulf Stream, and temperature sensitive animals and plants migrating further north, I think this may be just another sign of global warming (whatever the cause). Something for those who still deny global warming to ponder with the other signs. Although they seem curiously quiet lately.

    July 25, 2012 at 6:42 pm | Report abuse |
    • J-Pap

      Slowing of the gulf stream will decrease temperatures on the east coast, Greenland and Western Europe.

      July 25, 2012 at 7:41 pm | Report abuse |
    • Dave

      Whatever is the reason, we will be busy with arguments and I guess it will be too late for us by the time we will realize whats wrong with our climate.

      July 25, 2012 at 7:50 pm | Report abuse |
    • ADiff

      You do? LOL.... You did read the article, right?

      July 25, 2012 at 8:03 pm | Report abuse |
    • Jack O'Fall

      Large ice melts in Antarctica???
      Check your info. Antarctic ice cover on the continent is increasing and sea-ice cover has dramatically increased over the last 20 years. In fact, it seems to be the inverse speed of melting in the Arctic.
      Yes, the peninsula is having ice loss, but the main continent is not.

      July 25, 2012 at 8:34 pm | Report abuse |
  4. Newyorker

    NEWSFLASH: Black is not white. Gravity Exists. The Earth Goes Around the sun. And Man-made Climate Change is Real. Of course Fox News viewers and the feeble minds bought by Brothers Koch will disagree.

    July 25, 2012 at 6:42 pm | Report abuse |
    • jkflipflop

      What about natural climate change? Is it not real as well?

      July 25, 2012 at 7:20 pm | Report abuse |
    • guest

      It's getting hotter, period. Even if this is a natural variation, we should do something, like reduce our CO2 emissions.

      July 25, 2012 at 7:25 pm | Report abuse |
    • Mark

      Why do they call it Greenland? About 1,000 years ago, it was green with vegitation much of the year. Warming happens in cycyles...this one appears to be a long cycle.

      July 25, 2012 at 7:58 pm | Report abuse |
  5. Jim

    You're welcome Greenland.

    July 25, 2012 at 6:54 pm | Report abuse |
  6. Engineer in Raleigh

    Amazing how the right continues to believe the most insane nonsense in the face of overwhelming empirical evidence.

    July 25, 2012 at 7:00 pm | Report abuse |
    • Jack O'Fall

      There was a Government funded study of opinions in the US. IF found, much to their surprise that skepticism on global warming increased when scientific literacy increased.
      Hard to fit that into your vision of only the right is skeptical?

      July 25, 2012 at 8:36 pm | Report abuse |
  7. GOP hate america

    global warming is a hoax. thats what sarah palin says

    July 25, 2012 at 7:20 pm | Report abuse |
  8. Me

    So if it happened 123 years ago does that mean they had global warming back then?

    July 25, 2012 at 7:25 pm | Report abuse |
    • Dave

      It means that they don't have records for time before that.

      July 25, 2012 at 7:47 pm | Report abuse |
    • skookumchuck

      The scientists quite plainly state that it happened in the past (more than once) and that they cannot say it was caused by global warming. It seems they are a lot more honest than you are if you are implying that they claim it happened because of GW.

      July 25, 2012 at 7:52 pm | Report abuse |
  9. Me

    Facts? Do they have video footage?

    July 25, 2012 at 7:26 pm | Report abuse |
  10. ryantorgeson

    But the bible doesn't say ANYTHING about the planet getting warmer.

    July 25, 2012 at 7:40 pm | Report abuse |
  11. timex

    On an optimistic note.The growing season will be a lot longer in Greenland once all of the glacial ice is gone.

    July 25, 2012 at 7:44 pm | Report abuse |
    • skookumchuck

      When all of the ice on Greenland is gone, sea level will be 7 meters higher than it is today. Wall Street is only 1 meter above sea level, so much of Manhattan will be gone too. With luck the increased food production in Greenland will keep less Americans from starving to death.

      July 25, 2012 at 7:56 pm | Report abuse |
  12. decredico

    The reason it is called GREENLAND is because 1,000 years ago it was green and was used as farm land. There have been plenty of time in the past few thousand years it has seen a lot less ice than it has today.

    July 25, 2012 at 7:45 pm | Report abuse |
    • skookumchuck

      Wrong, it was named Greenland to attract settlers. Look it up for yourself.

      July 25, 2012 at 7:56 pm | Report abuse |
    • mike

      What you say is incorrect and completely false.

      July 25, 2012 at 8:05 pm | Report abuse |
    • KORA

      Used as farmland 1000 yrs ago? Good one, I suppose Iceland was...ice 1000 yrs ago? And aliens used the ice to sculpt pyramids.

      July 25, 2012 at 8:34 pm | Report abuse |
  13. decredico

    The earth is actually cooling at the present moment.

    July 25, 2012 at 7:46 pm | Report abuse |
  14. Patriot

    Starting to worry that the Mayans had it right.

    July 25, 2012 at 7:55 pm | Report abuse |
  15. pogojo

    Wow did they find new civilizations? artifacts from the last time this was not covered by ice? i bet there are some very nice discoveries just waiting to be found.

    July 25, 2012 at 8:00 pm | Report abuse |
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