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West Antarctic Glaciers Have Been Retreating For Last 7500 Years

August 7, 2016
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By Paul Homewood 

 

image

http://www.sciencemag.org/news/1999/10/antarctic-ice-beats-retreat

 

Climate scientists, with their new toys, would like you to believe that glacier retreat in West Antarctica is a recent phenomenon, caused by man.

Back in 1999 however, scientists revealed that these glaciers have actually been retreating at a fairly steady rate for at the last 7500 years:

 

An icy crust covering part of Antarctica has receded steadily for the last 20,000 years and may continue to do so regardless of human impacts on climate, a new study suggests. At its current rate of retreat, the ice will disappear in 7000 years, researchers report in tomorrow’s Science. However, the team cannot rule out a sudden collapse of the ice sheet in the next few centuries–an event that would raise sea levels worldwide by 5 or 6 meters.

The West Antarctic Ice Sheet is a mass of thick glaciers spanning nearly a million square kilometers. It rests on bedrock that sits below sea level. Contact with the gradually rising ocean may make the sheet more unstable than ice at higher elevations elsewhere on Antarctica. Indeed, when glaciologists drilled through the ice sheet, they found signs that it has disintegrated completely sometime within the last 1.3 million years, in a climate not much warmer than today’s (Science, 3 July 1998, p. 17). However, researchers had few details about the timing and extent of melting during recent millennia.

The new study pins down several dates and locations that trace the ice sheet’s shrinkage. The team–led by glaciologist Howard Conway of the University of Washington in Seattle and geologist Brenda Hall of the University of Maine, Orono–used radar to image old layers within the ice, which revealed its growth and decay over time. The researchers also used radiocarbon dating to analyze the ages of organic material left high and dry on beaches as the ice sheet melted away to expose land, which rises as the weight is lifted during the ice’s retreat. These and other methods revealed a pattern of steady retreat at an average rate of 120 meters per year over the last 7500 years. "We suspect this is an ongoing and long-term natural cycle triggered by rising sea levels at the end of the last ice age," says Conway. The relentless melting would continue even without human-induced climate changes, he believes.

"This is top-notch work," says glaciologist Robert Bindschadler of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The study bolsters a fragile consensus that gradual retreat, rather than sudden collapse, is the most likely fate of the ice sheet during the next few thousand years, he says. However, Bindschadler cautions, atmospheric warming may soften the ice and hasten its flow to the sea.

http://www.sciencemag.org/news/1999/10/antarctic-ice-beats-retreat

12 Comments leave one →
  1. G S permalink
    August 7, 2016 3:15 pm

    So much for the CA portion of CAGW. The Laurentide ice sheet which covered all of present day Canada and northern US began melting 100,000 years ago. Log before humans allegedly caused CO2 warming. Follow the money and we’ll find out who is really benefitting from this mass CAGW hysteria.

  2. August 7, 2016 5:13 pm

    Reblogged this on Climate Collections.

  3. Sara Hall permalink
    August 7, 2016 6:06 pm

    My dozy female brain keeps asking itself how they can ever measure the historic CO2 content of ice that’s thawed. Is there a way? Maybe I need another glass of the red stuff….

  4. 4TimesAYear permalink
    August 8, 2016 4:11 am

    Reblogged this on 4timesayear's Blog.

  5. August 8, 2016 8:11 am

    ‘these glaciers have actually been retreating at a fairly steady rate for at the last 7500 years’

    Any sign of climate spin doctors retreating yet?

    • ray permalink
      August 8, 2016 11:42 am

      “Any sign of climate spin doctors retreating yet?”

      That will take much longer than 7,500 years.

  6. August 8, 2016 8:14 am

    Reblogged this on Climatism and commented:
    Climate change update…

  7. August 8, 2016 12:22 pm

    From “Science Daily” Jan. 22, 2008: “The first evidence of a volcanic eruption from beneath Antarctica’s most rapidly changing ice sheet has been reported. The volcano on the West Antarctic Ice Sheet erupted 2000 years ago (325BC) and remains active. The subglacial volcano has a ‘volcanic explosion index’ of around 3-4. Heat from the volcano created melt-water that lubricates the base of the ice sheet and increases the flow towards the sea.”

    Could there possibly be a connection?? Of course not.

  8. dennisambler permalink
    August 8, 2016 1:23 pm

    “retreating at a fairly steady rate for at the last 7500 years:”

    Even longer:
    BAS Press Release 4/2005, (23 Feb 2005)
    A 2005 Durham University study of George VI Ice Shelf on the Antarctic Peninsula showed that this supposedly ‘healthy’ ice shelf experienced an extensive retreat about 9500 years ago, more than anything seen in recent years. The retreat coincided with “a shift in ocean currents that occurred after a long period of warmth”.

    The scientists analysed sediments from the bottom of a freshwater lake close to the edge of the present George VI Ice Shelf. The results revealed that about 9500 years ago the ice shelf retreated, allowing the sea to flood into the lake. The ice shelf didn’t reform until 1500 years later, and has been present ever since.

    The Prince Gustav Ice Shelf collapsed in 1995 and had also collapsed several thousand years ago. (Pudsey and Evans, BAS).

  9. August 9, 2016 3:26 pm

    It’s odd there is no mention of subglacial volcanism in the vicinity of the Thwaites glacier. Other reports single out this factor as playing a role in the WAIS melting that is popularly
    attributed to “warm” ocean water heated by GW. Science also ignores the possibility of a climate reversal that sooner or later may bring an end to the Holocene retreat overall, as accretion takes takes over once again.

    • August 10, 2016 1:44 pm

      Why would you mention anything which does not support your “a priori”, “settled science” conclusions? It’s not as though we are dealing with honest folks filled with integrity here.

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