Satellites reveal sudden Greenland ice melt

 
Nasa images reveal the extent of the  surface melt over Greenland’s ice sheet on July 8 (l) and July 12 (r) The first image shows Greenland's ice sheet on 8 July, the second, taken four days later, shows the area where ice has melted at the surface

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The surface of Greenland's massive ice sheet has melted this month over an unusually large area, Nasa has said.

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.

Start Quote

Melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time”

End Quote Lora Koenig Nasa Goddard Space Flight Center

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."

Watch this space

He said that, because this Greenland-wide melting has happened before - in 1889 - scientists are not yet able to determine whether this is a natural but rare event, or if it has been sparked by man-made climate change.

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The observation is in my view much more important than the recently reported break up of a large iceberg from Petermann Glacier”

End Quote Poul Christoffersen Scott Polar Research Institute

"Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time," said Lora Koenig, a glaciologist from Nasa's Goddard Space Flight Center in Maryland and a member of the research team analysing the satellite data.

"But if we continue to observe melting events like this in upcoming years, it will be worrisome."

Prof Eric Wolff, from the British Antarctic Survey (Bas) told BBC News: "There have clearly been some very warm days in Greenland this month. As a result, the surface snow has melted across the whole ice sheet.

"This is confirmed by some of my international colleagues who are on the ground at the NEEM ice core drilling site in north Greenland - they are reporting several days with temperatures above zero, and ice layers forming in the snow.

"While this is very unusual, as always we cannot attribute any individual extreme event to climate change: We will have to wait and see if more such events occur in the next few years to understand its significance for both the climate and the health of the ice sheet."

Dr Poul Christoffersen, a glaciologist and engineer at the Scott Polar Institute in Cambridge, told BBC News: "The melting seen in the satellite data is unprecedented, as it extends all the way across the ice sheet including the summit, which is located 3,200 m above sea level. Melting is usually limited to less than 2000m elevation."

The news comes just days after Nasa satellite imagery revealed that a massive iceberg, twice the size of Manhattan, had broken off the Petermann Glacier in Greenland.

"The observation [from Greenland] is in my view much more important than the recently reported break up of a large iceberg from Petermann Glacier," Dr Christofferson added.

Nasa's Tom Wagner said: "This event, combined with other natural but uncommon phenomena, such as the large calving event last week on Petermann Glacier, are part of a complex story."

Scientists said they believed that much of Greenland's ice was already freezing again.

 

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  • rate this
    +2

    Comment number 700.

    This is just like worrying if you start to go bauld, it is inevitable barring in mind what we have been upto over the last 200 year.
    It might mean the UK gets to be a slightly better climate, which will give us all something to cheer about, and thank god we dont live in the Maldives.

  • rate this
    +1

    Comment number 699.

    While a thought provoking (and comment provoking) article, I'd like to see a comparison of the solar energy output charted against cycles like this 150 year cycle of melt. If the solar ouput shows no correlation to these events, I'd be surprised.

  • rate this
    -2

    Comment number 698.

    @636

    Yep, ecosystems adapt but over long periods. They adapt over short periods too, sometimes very rapidly! These adoptions are called HABITAT LOSS and EXTINCTION... At a time when the Word's Biodiversity is at great risk, these [environmental] pressures are placing ever greater pressure on the worlds ecosystems in addition to all the man-made chaos they encounter. No space to write more...

  • rate this
    +3

    Comment number 697.

    689 'greenland used to be a farming community for the vikings'; they farmed the edges; there's been an icecap there since the last ice age.

    And yes, it may be related to the position of the jetstream; some climate scientists at Cambridge suggested that low sunspot activity will cause this southwards shift in the jetstream; AGW is still happening though.

  • rate this
    -1

    Comment number 696.

    How can this be unprecedented when it's happened before? Just more alarmist nonsense.

  • rate this
    +2

    Comment number 695.

    679.Sibbwolf

    "Not to mention we can only work from the time that's been recorded. That is, Ice records. "

    Not entirely true - you can use Isotope-ratio mass spectrometry to get fairly useful ocean temperature data from Foraminifera (fossil plankton) going back millions of years...
    It's called Paleoclimatology...

  • rate this
    0

    Comment number 694.

    I wonder if this could have any connection to the southerly displacement of the jet stream which caused all the rain in June.
    Perhaps a southerly displacement over Europe was matched by a northerly displace over Greenland which allowed warm air access to Greenland's ice. And melted it.
    Well, just a thought.

  • rate this
    +8

    Comment number 693.

    @191 "The Global Warming God brigade "

    In the real world, we call them "scientists". Still, better to get your information from some website than listen to scientific consensus. After all, there was this video on YouTube....

  • rate this
    -3

    Comment number 692.

    OH MY GOD, WE'RE ALL GOING TO DIE!!!!!!!!!

  • rate this
    +1

    Comment number 691.

    wood pig : watch "Discovery Channel - Global Warming, What You Need To Know, with Tom Brokaw"
    There is a very good reason why the USA political parties are in total opposition on the subject of Climate Change
    Who ever controls the third largest economy in the world will have great power to save the rich & sacrifice the poor
    or
    Save the People no matter their level of wealth
    "Limited Resources"

  • rate this
    -1

    Comment number 690.

    "Scientists said they believed that much of Greenland's ice was already freezing again."

    So...why are we concerned again?

  • rate this
    -7

    Comment number 689.

    greenland used to be a farming community for the vikings ..it froze over and they left well guess what its gonna get a lot hotter but it aint because of us when this planet warms its because of the sun when this planet dies it will also be because of the sun just read about the life cycle of stars.

  • rate this
    -4

    Comment number 688.

    @ 659.David Agnew

    It's strange. Being a sceptic is essential in science. But to you, that's being 'denialistic'. It's pointlessly insulting and displays a deep fear that you may be wrong after all.

    You confirm my fears that AGW is bordering on a religion - you'll be calling me apostate next.

  • rate this
    0

    Comment number 687.

    @684, Yeah, I did send a comment into the BBC about the bad cropping. They have yet to make any sort of response.

  • rate this
    -7

    Comment number 686.

    There is evolution. Nothing has ever evolved on this earth. The decline in the ice is due to atmospheric warming and a sign of the end of the world. Check your Bible. You will find that end is near.
    The floods in different parts of the globe is a pointer to this fact. Last year there was massive flooding in Australia and Thailand and now in China.

  • rate this
    -1

    Comment number 685.

    173. Paul

    Spot on! Yet I've been called 'selfish' for not having children on the very grounds Paul states. Go figure...

  • rate this
    0

    Comment number 684.

    It appears, from the map (which lacks a legend), that ALL the ice has melted...

  • rate this
    +3

    Comment number 683.

    It's not all about CO2 which many seem to think. Although amounts are smaller, Methane (CH4) Nitrous oxides NOx have a far geater impact on the climate and health.
    Due to global warming large amounts of CH4 are being released from permafrost. Flatulence, (don't laugh) is another major source of it (not just from cows) and this gas is 20x more damaginbg than CO2.

  • rate this
    -1

    Comment number 682.

    Some people say there will be less land for farming and habitation. I remain cautiously optimistic. Can someone recommend a good real-estate agent in Greenland?

  • rate this
    +1

    Comment number 681.

    David Renner : And did you build your house underground with a wind turbine and solar panels for your future energy needs with a garden over your head and a big water storage tank under your feet?
    If you did the you really are "In like Flynn"
    That's what the Oil Moguls do not want, when the supplies get limited & there are NO alternatives the prices go UP & more money can be made

 

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