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)

    Kevin Costner had it all right. "Waterworld" wasn't was a look at our real future!

    July 25, 2012 at 12:42 pm | Report abuse |
    • aammeee

      The sky is falling, the sky is falling! Happens every 150 years on average.

      July 25, 2012 at 12:56 pm | Report abuse |
    • Jack

      Yes it happens about every 150 years, and the record high we've had happen about every 200+ years, and the ice caps melting happen about every 10000 years (maybe) but the problem these things are all happening NOW! Not randomly through out time but all at the same time. That is an indicator that something is wrong because all these things have never been recorded to happen at the same time.

      July 25, 2012 at 1:09 pm | Report abuse |
    • Roger

      The planet isn't warming. Exxon-Mobile told me so and I will obey as the weak minded fool that I am.

      July 25, 2012 at 1:15 pm | Report abuse |
    • Elizabeth

      I recall an article (I think it was in National Geographic) where explorers tried to figure out what happened to large lakes that disappeared in a day on Greenland's surface. Up close they learned that great fissures opened, sending all the water to the bottom of the ice sheet. These daring explorers climbed down the fissures to find that there is a great under-ice waterway that is undermining the ice and moving the glaciers.

      July 25, 2012 at 1:27 pm | Report abuse |
  2. Paul

    Hold one second here. 2012-150=1862. Please explain how Civil War error people knew the entire continent of Greenland melted? I call Shenanigans

    July 25, 2012 at 12:57 pm | Report abuse |
    • tim

      Read the article before posting:

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

      July 25, 2012 at 1:03 pm | Report abuse |
    • Steve you mean civil war 'era'?

      July 25, 2012 at 1:07 pm | Report abuse |
    • Not Paul

      The article clearly states that the information comes from core samples, a very reliable way of looking at the history of ice caps.

      Anyways, there's no evidence from this study that this has anything to do with global warming. There's also no evidence in this study that says it isn't; it's just another data point that needs to be looked at along with all the other data to form a larger picture. That picture does support global warming for the most part. However, being an extremist about it is counterproductive on either side of the argument.

      July 25, 2012 at 1:10 pm | Report abuse |
    • Dee

      It's called Ice Core analysis. It's one of those science thingy's. Probably way above your head.

      July 25, 2012 at 1:12 pm | Report abuse |
    • Sid AIrfoil

      Civil War ERA, not "error".

      July 25, 2012 at 1:18 pm | Report abuse |
    • Boater

      They didn't know..... WE know. How? Ice Core samples. The ice sheets work just like the rings in a tree. They examine the layers for things like thickness and content of certain chemicals. (for instance, the content of chemicals such as CO2 can tell them how old the ice is at a particular level, as CO2 levels in the atmosphere have been rising).

      July 25, 2012 at 1:38 pm | Report abuse |
    • Jason

      error = (read) era.

      July 25, 2012 at 4:33 pm | Report abuse |
    • peter

      I'm with you!
      And whats with these evolutionists types? Were they around to see the dinosaurs? IM GUESSING NOT!

      July 26, 2012 at 7:28 pm | Report abuse |
  3. Buffalo2002

    Science News Flash
    Heat Melts Ice !!!
    Cold freezes ice !!!
    More news in December 2012

    July 25, 2012 at 12:58 pm | Report abuse |
  4. Jeff

    Happened 123 years ago as well. So, is it happening now due to CO2 or is happening as part of a natural cycle? Ah, it must be CO2. If its a natural cycle a lot of people will be out of work.

    July 25, 2012 at 1:02 pm | Report abuse |
    • Jack

      If this were the only thing going on I would agree, but it's not. There are lots of "only happens every 50,100,200,10000 year" events happening at the same time. Wake up and smell the scorched earth. A little common sense goes a long way.

      July 25, 2012 at 1:28 pm | Report abuse |
    • Florida Bill

      Hmm, let's see unusual ice melts in Arctic and Antarctic, slowing of the Gulf Stream, temperature-sensitive plants and anmials migrating north, worst droughts in the midwest since the year I was born (1956). Whether this is a natural cycle or not it does appear to be happening and whatever the cause its going to have a big impact on us. Most of the population still lives in areas that will be vulernable to higher mean sea levels, our grain belt will move north to Canada and our deserts will grow. Be prepared to pay for higher food, higher insurance (to cover the losses from more powerful storms), more loss of life, higher government outlay for flood losses.

      July 25, 2012 at 6:50 pm | Report abuse |
  5. sbasler

    And the evidence keeps building

    We could have saved the earth but we were too damn cheap

    July 25, 2012 at 1:06 pm | Report abuse |
  6. BigD

    Well, where is Al Gore ... Global Warming. But wait this has happend in the past, oh say 150 yrs ago? Where did al the greenhouse gases come from then? cow farts? Maybe climate change is a bunch of BS and the Earth just naturally cycles warm and cold ...hmmmmm

    July 25, 2012 at 1:15 pm | Report abuse |
    • Roger

      yes – all the evidence means nothing – I agree! Hey do you have enough room for me to stick my head in the sand with you?

      July 25, 2012 at 1:19 pm | Report abuse |
    • phoenix224

      Or maybe 97.5% of climatologists say that climate change is real and that humans are the driving cause of it?

      July 25, 2012 at 1:34 pm | Report abuse |
  7. Robert

    Can anyone read besides me and one other guy? It is summertime, Ice melts, even in the artic circle in summertime, when the earth wobbles back tward space away from the ever increasingly hotter and hotter sun (look it up) the ice will once again melt. Savey? please if you are ignorant to the issue do some research befor posting, and get back to work your stealing from your employer. Unless your a Federal employee I understand this kind of activity is encouraged.

    July 25, 2012 at 1:15 pm | Report abuse |
    • bignevermo

      Scientists said the "unprecedented" melting took place over a larger area than has been detected in three decades of satellite observation.

      Melting even occurred at Greenland's coldest and highest place, Summit station.

      The thawed ice area jumped from 40% of the ice sheet to 97% in just four days from 8 July.

      Although about half of Greenland's ice sheet normally sees surface melting over the summer months, the speed and scale of this year's thaw surprised scientists, who described the phenomenon as "extraordinary".

      Nasa said that nearly the entire ice cover of Greenland, from its thin, low-lying coastal edges to its centre, which is 3km (two miles) thick, experienced some degree of melting at its surface.

      Until now, the most extensive melting seen by satellites in the past three decades was about 55% of the area.

      According to ice core records, such pronounced melting at Summit station and across the ice sheet has not occurred since 1889.

      "When we see melt in places that we haven't seen before, at least in a long period of time, it makes you sit up and ask what's happening," Nasa chief scientist Waleed Abdalati said.

      "It's a big signal, the meaning of which we're going to sort out for years to come."

      July 25, 2012 at 1:32 pm | Report abuse |
    • phoenix224

      97.5 % of climatoligists say that climate change is real and that humans have an effect on it.

      July 25, 2012 at 1:36 pm | Report abuse |
    • Hope


      Extraordinary, indeed!


      July 25, 2012 at 1:47 pm | Report abuse |
    • Austin

      The Earth's revolution around the sun is nearly circular. Seasons are caused by the 23.5 degree tilt in the Earth's axis, not buy the earth moving further and further away from the Sun.

      July 25, 2012 at 4:17 pm | Report abuse |
    • Florida Bill

      Do you mean the Arctic? Why don't you ask the polar bears that are starving due to the ice melt that's keeping them from their usual fishing territories whether they think that this is just a case of ice melting in the summer?

      July 25, 2012 at 6:53 pm | Report abuse |
    • peter

      Did YOU read the article? I'm pretty sure the WHOLE POINT of the article isn't "Greenland melting as usual! No concern here!"

      July 26, 2012 at 7:32 pm | Report abuse |
  8. Vinny

    If there's a global-warming apocalyptic event that forces us all back to the middle ages, I nominate Justin Bieber as the first person we should offer up as a sacrifice to the angry gods. Just sayin'.

    July 25, 2012 at 1:17 pm | Report abuse |
    • Roger

      That is something that both Republican's and Democrat's can agree on. It's a start!

      July 25, 2012 at 1:20 pm | Report abuse |
    • Hope

      I think you got it right. Wouldn't you be angry if you were him?

      Just, look at us; ALL of us!

      July 25, 2012 at 1:38 pm | Report abuse |
  9. Hope

    Bye-Bye Dubai!



    July 25, 2012 at 1:26 pm | Report abuse |
  10. thinking logically

    sbasler - We could have saved the earth but we were too damn cheap
    Yes, they said the very same thing in 1889.

    July 25, 2012 at 1:26 pm | Report abuse |
  11. Eusebio Mnauel Vestias Pecurto

    Ora aquim temos a prova que o nosso planeta esta a mudar Quando é que os nosso lideres mundiais olham para o nosso planeta

    July 25, 2012 at 1:29 pm | Report abuse |

    Let's see, 2012 – 150 would put it at 1939. That means Global Warming started when the Carter went to war with Nevada!

    July 25, 2012 at 1:31 pm | Report abuse |
    • phoenix224

      You might want to double check your math.

      July 25, 2012 at 1:33 pm | Report abuse |
    • peter

      Wait, people are talking about how the 150 year cycle and global warming are NOT connected. Are you a conservative or something?

      July 26, 2012 at 7:42 pm | Report abuse |
  13. SgtSerge

    This is a great study more to be done. I still think we should be aware of what is going up in to our atmosphere but the more and more I read real data the more I see that this sort of thing has happened for as far back as we can see. To me the big question will be how to get metrics on the natural tempature changes so we can filter those out and get a real idea of how we can affect an environment.
    Anyways great news keep it coming!

    July 25, 2012 at 1:33 pm | Report abuse |
  14. SgtSerge

    LOL looks like Penn State does not tech math or simple logic, I don't need a pen and paper to tell you your math is way off =)

    July 25, 2012 at 1:34 pm | Report abuse |
  15. Boater

    The anti-climate change people remind me of the smokers of yesterday.... I didn't KNOW that smoking was bad for me?

    July 25, 2012 at 1:36 pm | Report abuse |
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