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
    0

    Comment number 720.

    @ 702.BLACK_PEARL (Again!!)

    One thing I have noticed in the video http://www.youtube.com/watch?v=YxbOSB7zDgY is that there seems to be jumps at about 5 minutes, as if the video has been edited slightly......

  • rate this
    +1

    Comment number 719.

    @711

    Ah, but when it comes to exstinctions, we are already living in a time of biodiversity loss. The planets biodiversity has more than enough on its plate dealing with humanities cockups. The added pressures of climate change will only aggregate tye situation. Of course, some species will adapt, shift ranges (if plausable) and potentially thrive, but that does not help global biodiversity.

  • rate this
    -2

    Comment number 718.

    712.@ owl905

    It happens about once every 150 years ... this one is "right on time". 2012-1889 = 123. Close ... or not.

    Well is it? Do you know? 'It happens about once every 150 years' is not enough information to know if it's on time or not.

    But that didn't stop you ...'It's another in a growing compendium of extreme anomalies'.

    No it isn't.

  • rate this
    -2

    Comment number 717.

    Lora Koenig,glaciologist,and member of the research team states-"Ice cores from Summit show that melting events of this type occur about once every 150 years on average." Please note-EVERY 150 years. Not just that it happened 150 years ago,EVERY 150 years-so it has happened MANY times before. She also states that this melt is "right on time".

  • rate this
    +2

    Comment number 716.

    What should be noted is that this melting is happening sooner than 150 years and occurred over a very short period of time. Add the huge icebergs that have been calved recently from both Greenland and the Antarctic and it's clear that something is changing with our climate. It's foolish to think that our cars, industries and chemical usage hasn't affected our environment and climate negatively.

  • rate this
    -1

    Comment number 715.

    Hardly surprising that the ice melted, the Jetstream was taking a different trajectory from normal.

    Totally agree with 699. richardbamberg that this is almost certainly (4 sigma?) evidence of cyclical solar activity and not in any way related to human activity.

  • rate this
    -1

    Comment number 714.

    Discovery Channel - Global Warming, What You Need To Know, with Tom Brokaw - Comprehensive report

    Huge amounts of CO2 can be absorbed by plankton in the oceans, all we have to do is seed the oceans with Iron sulphate
    http://www.bbc.co.uk/news/science-environment-18885083

    google "Dumping iron sulphate in sea a cure for climate change: study"

    What the heck are we waiting for?

  • rate this
    +4

    Comment number 713.

    I think it's incredibly revealing how many of the lowest rated 'climate change is a myth' look like they were typed by drunk chimps

  • rate this
    +3

    Comment number 712.

    It happens about once every 150 years ... this one is "right on time". 2012-1889 = 123. Close ... or not.

    It's another in a growing compendium of extreme anomalies that's a facet of the heating world. More recent research is confirming that the swing in climate shift hits the Arctic the strongest. GHG pollution and reduced albedo is the sickle-bearer in the background of this new anomaly.

  • rate this
    -3

    Comment number 711.

    @ 698. Nb You say that rapid evolution results in HABITAT LOSS and EXTINCTION. In classic AGW mode, you only mention worst case scenarios.

    Steven Jay Gould came up with the term 'punctuated equilibirium', where after many generations of not much evolution, a change in climate forces a species to adapt quickly.

    There you go, a non-worst-case scenario.

  • rate this
    -3

    Comment number 710.

    Stop the presses!

    Ice melts in Artic during summer.

    'We're all doomed Mr Mainwaring.' Says the BBC.

  • rate this
    0

    Comment number 709.

    People, whether global warming is real or not is irrelevant. It's incredibly obvious that we are not going to make any real moves to change. The only real discussion should be what our legacy turn out to be; the generation that held our course to a brighter world; or the generation that buried our heads in the sand denied our children a future.

  • rate this
    +1

    Comment number 708.

    I'd be fascinated to know what possible value there is in comparing 1889's records with these satellite images? Are there even aerial shots of the melt from back then?

    Always makes me laugh that people dismiss the unnatural influence of human waste of natural resource on the grounds that the climate would change anyway - as if that has ever been in question.

  • rate this
    +3

    Comment number 707.

    @705 'Temp increase since 1940 0.4C'

    That's a seven year old attempt to discredit AGW, the thing about AGW as a theory is that it has survived unprecedented attacks from all quarters, and is still the model of choice for climatologists. Cherry picking data won't knock what is now a well-evidenced theory.

  • rate this
    -2

    Comment number 706.

    @ 702.BLACK_PEARL

    Thank you for those links, well worth a look at especially the David Bellamy seminar.

  • rate this
    -6

    Comment number 705.

    697.StanleyRIP
    689 'greenland used to be a farming community

    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.
    ****
    Temp increase since 1940 0.4C

  • rate this
    -1

    Comment number 704.

    "In the deserts of this world" Uwe George .....

  • rate this
    -4

    Comment number 703.

    Wow, a hunk of ice melts and it's a sweltering 84 degrees in my back garden today.I love this global warming!

    Do we really want ti live in the next ice age? I don't.

  • rate this
    -4

    Comment number 702.

    Very misleading graphics... why ?
    Ice sheets on Greenland come & go.
    Its a natural cyclic event.
    Forests etc replace the ice.
    See very lasted field study
    http://www.youtube.com/watch?v=YxbOSB7zDgY

    A little lighter fair
    David Bellemy on history of natural temp swings.
    http://www.youtube.com/watch?v=etZ9-u7Yg8M&feature=related
    http://www.youtube.com/watch?v=jvCoWiFri_8&feature=related

  • rate this
    +2

    Comment number 701.

    The human race is following the pattern of microbes on an apple - continuing to multiply exponentially, turning resources into waste. Eventually the apple is gone, and the microbes die.

    All governments should to introduce population control and also limit the endless economic drive to 'add value' by using more resources. Unfortuately, human greed and selfishness will prevail until too late.

 

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