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posted by Fnord666 on Saturday June 16 2018, @02:02PM   Printer-friendly
from the slippery-slope dept.

Arthur T Knackerbracket has found the following story:

Storm-driven ocean swells have triggered the catastrophic disintegration of Antarctic ice shelves in recent decades, according to new research published in Nature today.

Lead author Dr Rob Massom, of the Australian Antarctic Division and the Antarctic Climate and Ecosystems Cooperative Research Centre, said that reduced sea ice coverage since the late 1980s led to increased exposure of ice shelves on the Antarctic Peninsula to ocean swells, causing them to flex and break. "Sea ice acts as a protective buffer to ice shelves, by dampening destructive ocean swells before they reach the ice shelf edge," Dr Massom said. "But where there is loss of sea ice, storm-generated ocean swells can easily reach the exposed ice shelf, causing the first few kilometres of its outer margin to flex."

"Over time, this flexing enlarges pre-existing fractures until long thin 'sliver' icebergs break away or 'calve' from the shelf front. This is like the 'straw that broke the camel's back', triggering the runaway collapse of large areas of ice shelves weakened by pre-existing fracturing and decades of surface flooding."

Study co-author Dr Luke Bennetts, from the University of Adelaide's School of Mathematical Sciences, said the finding highlights the need for sea ice and ocean waves to be included in ice sheet modelling. This will allow scientists to more accurately forecast the fate of the remaining ice shelves and better predict the contribution of Antarctica's ice sheet to sea level rise, as climate changes. "The contribution of the Antarctic Ice Sheet is currently the greatest source of uncertainty in projections of global mean sea level rise," Dr Bennetts said.

-- submitted from IRC


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  • (Score: 3, Insightful) by maxwell demon on Saturday June 16 2018, @05:43PM (7 children)

    by maxwell demon (1608) on Saturday June 16 2018, @05:43PM (#694006) Journal

    Yep. When I read the title, just about my first thought was, "So, ocean swells had no effect on the ice until we looked for effects? There were no ocean swells hammering the ice ten years ago, but now there are?"

    If you hadn't stopped at the title, but read the summary, you would have gotten the answer to your question:

    The ocean swells always had an effect, but in the past there were less strong swells which meant less of an effect. And there were less strong swells because sea ice dampened the swells.

    How do we KNOW what was happening here, there, or elsewhere, thousands of years ago, before we ever started measuring things?
    From the summary, emphasis by me:

    reduced sea ice coverage since the late 1980s
    I'm pretty sure that the late 1980s are not thousands of years ago, and I also bet people were measuring sea ice coverage back then (not because of climate research, but because it is important for navigation).

    --
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  • (Score: 1) by khallow on Sunday June 17 2018, @01:25AM (4 children)

    by khallow (3766) Subscriber Badge on Sunday June 17 2018, @01:25AM (#694094) Journal

    The ocean swells always had an effect, but in the past there were less strong swells which meant less of an effect.

    Unless, of course, that wasn't true. Always the problem with making assertions about knowledge gaps.

    • (Score: 2) by dry on Sunday June 17 2018, @02:11AM (3 children)

      by dry (223) on Sunday June 17 2018, @02:11AM (#694108) Journal

      I watched a documentary on an Arctic village that was getting washed away by the swells that had shown up due to no ice cover in the summer. It was pretty dramatic, houses falling into the ocean, the villagers having to move inland and the shoreline made out of easily eroded material. This village had existed for at least 50 years without problems until the last few years when the sea ice retreated and the island itself still existing points to a long time with calm ice covered seas.

      • (Score: 1) by khallow on Sunday June 17 2018, @03:35AM (2 children)

        by khallow (3766) Subscriber Badge on Sunday June 17 2018, @03:35AM (#694132) Journal

        It was pretty dramatic

        The problem is that the world is always changing. There's always something dramatic happening.

        This village had existed for at least 50 years without problems until the last few years when the sea ice retreated and the island itself still existing points to a long time with calm ice covered seas.

        50 years isn't a very long time nor would the village be built far away from the sea.

        • (Score: 2) by dry on Sunday June 17 2018, @04:04AM (1 child)

          by dry (223) on Sunday June 17 2018, @04:04AM (#694136) Journal

          The problem is that the world is always changing. There's always something dramatic happening.

          That's not the point. The point being that change can bring destructive swells.

          50 years isn't a very long time nor would the village be built far away from the sea.

          Once again you miss the point, at least 50 years more likely closer to 75 since they were forced to settle into housing and the people have been living there for thousands (10+?) of years, and the fact that the island was very erodible. I've lived on the ocean, erosion doesn't happen very fast as the easily eroded shoreline is long eroded away.

          • (Score: 1) by khallow on Sunday June 17 2018, @12:14PM

            by khallow (3766) Subscriber Badge on Sunday June 17 2018, @12:14PM (#694216) Journal

            That's not the point. The point being that change can bring destructive swells.

            Not from your story, it isn't. The media wouldn't have been interested in that island being slowly eaten up (or perhaps eaten up in bouts over thousands of years), until houses started sliding into the sea. I grant that global warming presents a plausible scenario with a combination of loss of protective ice and thawed permafrost could result in highly accelerated local erosion. But that might just be a phenomenon that's been repeated for thousands of years. It's only now that we've had a chance to see it in action.

            Once again you miss the point, at least 50 years more likely closer to 75 since they were forced to settle into housing and the people have been living there for thousands (10+?) of years, and the fact that the island was very erodible.

            The houses weren't thousands of years old. In the past, they would have just moved inland a bit and nobody would have reported on the situation both due to the lack of media and the lack of drama.

            I've lived on the ocean, erosion doesn't happen very fast as the easily eroded shoreline is long eroded away.

            Unless there's a lot of shoreline to erode, such as with the cliffs of Dover.

  • (Score: 2) by Runaway1956 on Sunday June 17 2018, @01:30AM (1 child)

    by Runaway1956 (2926) Subscriber Badge on Sunday June 17 2018, @01:30AM (#694096) Journal

    See Khallow's response. The assertion that ocean swells weren't so strong fifty, or a hundred, or a thousand years ago is preposterous.

    • (Score: 0) by Anonymous Coward on Sunday June 17 2018, @05:18PM

      by Anonymous Coward on Sunday June 17 2018, @05:18PM (#694291)

      Which has no besring on the topuc really since the problem is lack of sea ice absorbing the energy.