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.

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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
    -4

    Comment number 600.

    LET'S STICK TO THE SUBJECT.. Greenlands melted more in just a
    4 days than it has in decades. I live in America and I don't think
    we need to worry about Ocean levels rising like y'all do. Scientists
    believe they can predict the future and can explain the past. Funny.
    Something that was suppose to take hundreds of years took only 4 days.
    H E double hockey sticks just got a little hotter! !!!!!!!!

  • rate this
    -3

    Comment number 599.

    Sea level rise, floods, draughts, famines wars, all sorst of plagueshave been recurring on and on over and over again. So why bother?
    Why can't we just keep on making money and worry about our investments, GDP growth and so on, and so forth?
    Just one thing: keep the market happy, and everybody's happy.
    THis climate change theory is a scam anyway, isn't it?

  • rate this
    +3

    Comment number 598.

    All this talk of global warming and yet Governments still go on about growth even though growth comes at a cost - more devestation to the planet.

    The solution = encourage population decline.

  • rate this
    +8

    Comment number 597.

    579 truthhurtspainfully

    "really, why's that [climate change causing more extreme weather] then?, I'd ask you to proove but you couldn't."

    I can only presume you missed out on science GCSEs. Heat is energy; apply it to the atmosphere and you therefore get higher winds, which are what drives weather.

    It depresses me that your opinion is equal to those of people who know what they're on about.

  • rate this
    -3

    Comment number 596.

    The surrface glacier melt is rather reasuring since apparently they are no worse off than 1889. That's 123 years ago, hmm, flat conditions for over a century. The changes in our planet still proceed with majestic slowness

  • rate this
    -3

    Comment number 595.

    As history has shown, this isn't a new thing! We had a mini ice age not that long ago in the greater scheme of things- The Romans were growing grapes "up North" in their time, so it isn't new. The only thing I would say is people should be becoming far more aware of the waste or resources, sort that out and people would start using far less carbon wise and help solve the problem that way!

  • rate this
    -1

    Comment number 594.

    586.Ceiswyn

    The problem is that you cannot compare like with like. You only have averages for the Carboniferous so that's all you can work with. There seems to be a correlation between CO2 and temp at short timescales but that doesn't necessarily mean a cause and effect relationship. Comparing data from different Geological periods shows a more complex picture...

  • rate this
    +2

    Comment number 593.

    584.Dominico
    19 Minutes ago
    Who ever said ignorance was bliss?


    I think it was Thomas Gray

    "Where ignorance is bliss, 'tis folly to be wise" - poem about Eton, I think!

  • rate this
    +5

    Comment number 592.

    @579, again, it's down to fundamental physics - flow of energy. it can't just disappear. The problem with the "green-house gases" is they lock the temperature in (note, one more reason why CO2 is overblown). Water is the worst of the lot for the same number of units.

    Locking in more energy means more wind, rain and storms. Thus, more extreme weather.

    @590, we're in a reduced sunspot phase.

  • rate this
    +4

    Comment number 591.

    The damage that has already been caused so far this year has been costly to me
    One storm broke a tree branch that flattened fences and brought down wires, lost frozen food and paid for clean up
    I have a dead lawn from no rain & extreme heat, water shortages have caused loss of crops in my state
    Temps hit 100 more this year than in past records
    Storms are more extreme with lightning damage & hail

  • rate this
    -6

    Comment number 590.

    Human beings can do nothing about climate change which is probably related to sunspot activity. In medieval times 800AD - 1200AD the earth was much warmer. The Vikings settled in Greenland and grew crops and raised livestock for a couple of hundred years. Sea levels couldn't have been much higher since the coastal historic sites (Alexandria etc) are still in the same place.

  • rate this
    +1

    Comment number 589.

    Learn to swim...

  • rate this
    +2

    Comment number 588.

    562.Argent Pur, A number of theories; Increases in CO2, increases in NOx & changes in the earths 'tilt' in relation to the sun Major increases in solar activity. Also a slight shift in the earths orbit causing changes in wind patterns moving warmer air from the equators towards the poles. None of which is there enough evidence to be conclusive. Truth, prob a combination of the above.

  • rate this
    +1

    Comment number 587.

    There is a connection here with another article elsewhere in this site:
    Why are we obsessed by growth?
    By Anthony Reuben
    Business reporter, BBC News
    http://www.bbc.co.uk/news/business-18967294

  • rate this
    +10

    Comment number 586.

    'In the Carboniferous period there was 3x today's CO2 and almost identical average temperature.'

    a) You're forgetting the huge effect that the position of the continental plates has on climate, and
    b) You're comparing a point temperature with a temperature averaged over, uh, 60 million years? And complaining about other people's science? Really??

  • rate this
    -2

    Comment number 585.

    Re my 565: It's likely at least part of this is natural rebound from the Little Ice Age. The earth's coped with worse in the past, but unlike previous centuries, you can't just dismantle your home and rebuild it inland or on higher ground, so politicians need to look at the trend and plan future adaptions, as the earth will get warmer even if all human-lit fires were immediately extinguished.

  • rate this
    +3

    Comment number 584.

    Who ever said ignorance was bliss?

  • rate this
    +8

    Comment number 583.

    @573, true. But our cycle is showing something that hasn't happened before, and that's why climate change scientists talk a lot about the human impact - it's currently the only theory that explains the unusual trends.

    @562, someone did respond.

    @nearly all, this story is NOT about climate change anyway! It's about an event we're witnessing, but not categorised yet, due to the nature of science.

  • rate this
    -2

    Comment number 582.

    320. Dragonwight Perhaps we'll need some of our oil reserves to leave & survive before the planet ceases to exits. Instead we'll just waste oil away by driving inefficient cars when we could cycle, making things we don't really need & chucking them away to landfill or heating/cooling our buildings so we're just right. We won't even save oil for future generations in a few hundred years time!

  • rate this
    0

    Comment number 581.

    Steven@558: what has happened over the last 100 years or so is increased travel, and the urge for 'undeveloped' nations to play catch-up with deforestation and pollution, the effects of which will only become provable after another few 100 years. Dartmoor used to be woodland until progressively cleared with the early development of agriculture and is now the closest we have to a native wilderness.

 

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