West Antarctic Warming Faster Than Thought, Study Finds

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West Antarctica has warmed much more than scientists had thought over the last half century, new research suggests, an ominous finding given that the huge ice sheet there may be vulnerable to long-term collapse, with potentially drastic effects on sea levels.


A paper released Sunday by the journal Nature Geoscience reports that the temperature at a research station in the middle of West Antarctica has warmed by 4.4 degrees Fahrenheit since 1958. That is roughly twice as much as scientists previously thought and three times the overall rate of global warming, making central West Antarctica one of the fastest-warming regions on earth.

“The surprises keep coming,” said Andrew J. Monaghan, a scientist at the National Center for Atmospheric Research in Boulder, Colo., who took part in the study. “When you see this type of warming, I think it’s alarming.”

Of course, warming in Antarctica is a relative concept. West Antarctica remains an exceedingly cold place, with average annual temperatures in the center of the ice sheet that are nearly 50 degrees Fahrenheit below freezing.

But the temperature there does sometimes rise above freezing in the summer, and the new research raises the possibility that it might begin to happen more often, potentially weakening the ice sheet through surface melting. The ice sheet is already under attack at the edges by warmer ocean water, and scientists are on alert for any new threat.

A potential collapse of the West Antarctic ice sheet is one of the long-term hazards that have led experts to worry about global warming. The base of the ice sheet sits below sea level, in a configuration that makes it especially vulnerable. Scientists say a breakup of the ice sheet, over a period that would presumably last at least several hundred years, could raise global sea levels by 10 feet, possibly more.

Written By: Justin Gillis
continue to source article at nytimes.com

6 COMMENTS

  1. In reply to #1 by aquilacane:

    The several hundred years part is why nothing will happen.

    Can I qualify something please?

    When you say “nothing will happen”, do you mean, nothing will be done about it, or do you mean, there will be no consequence?

  2. Err, as an aside…. was I the only person initially confused by the title saying “West Antarctic” ?

    I mean, in a polar region which side do you define as West ?

    But then of course I read the article referring to “West Antarctica”, apparently a geographical region also known as Lesser Antarctica; Which apparently is the portion of Antarctica lying within the Western Hemisphere. Of course I’m familiar with the term Western Hemisphere but then I thought about how its defined and was surprised to find it is the hemisphere west of the Greenwich meridian – meaning London is in both the Western and Eastern hemisphere? Who knew? So the Western hemisphere is actually the hemisphere East of the Anitmeridian or 180th Meridian which is used as the International Date Line.

    Wow, a little journey of knowledge around the globe. You learn something knew everyday. What was the article about again?

    ( Antarctica is in the north yeah? [ I'm kidding! ] )

  3. One of the features of West Antarctica, is that unlike the high plateau areas of Antarctica, it is a collection of island joined together by ice.

    Ice floats, so with rising sea-levels from global warming allowing warmer water access under the ice, and surface melt running down to lubricate the flow of ice, a rapid break-up is possible.

    Work has been done on this in Greenland:-

    Thousands of lakes form on top of Greenland’s glaciers every summer, as sunlight and warm air melt ice on the surface. Past satellite observations have shown that these supraglacial lakes can disappear in as little as a day, but scientists did not know where the water was going or how quickly, nor the impact on ice flow.

    Researchers have hypothesized that meltwater from the surface of Greenland’s ice sheet might be lubricating the base. But until now, there were only theoretical predictions of how the meltwater could reach the base through a kilometer of subfreezing ice.

    “We set out to examine whether the melting at the surface—which is sensitive to climate change—could influence how fast the ice can flow,” Das said. “To influence flow, you have to change the conditions underneath the ice sheet, because what’s going on beneath the ice dictates how quickly the ice is flowing.”

    “If the ice sheet is frozen to the bedrock or has very little water available,” Das added, “then it will flow much more slowly than if it has a lubricating and pressurized layer of water underneath to reduce friction.”
    whoi.edu/page

  4. In reply to #4 by Telic:

    Err, as an aside…. was I the only person initially confused by the title saying “West Antarctic” ?

    Alt Text
    Alt Text

    A right click followed by “view image” will show the features mentioned in my earlier comment.

    The West Antarctic Ice Sheet (WAIS) is the segment of the continental ice sheet that covers West (or Lesser) Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains which lies in the Western Hemisphere. The WAIS is classified as a marine-based ice sheet, meaning that its bed lies well below sea level and its edges flow into floating ice shelves. The WAIS is bounded by the Ross Ice Shelf, the Ronne Ice Shelf, and outlet glaciers that drain into the Amundsen Sea. – wikipedia

    It is estimated that the volume of the Antarctic ice sheet is about 25.4 million km3, and the WAIS contains just under 10% of this, or 2.2 million km3.[1] The weight of the ice has caused the underlying rock to sink by between 0.5 and 1 kilometres[2] in a process known as isostatic depression.

    Under the force of its own weight, the ice sheet deforms and flows. The interior ice flows slowly over rough bedrock. In some circumstances, ice can flow faster in ice streams, separated by slow-flowing ice ridges. The inter-stream ridges are frozen to the bed while the bed beneath the ice streams consists of water-saturated sediments. Many of these sediments were deposited before the ice sheet occupied the region, when much of West Antarctica was covered by the ocean. The rapid ice-stream flow is a non-linear process still not fully understood; streams can start and stop for unclear reasons.

    When ice reaches the coast, it will continue to flow outward onto the water. The result is a large, floating shelf of ice affixed to the continent

    Potential Collapse

    Large parts of the WAIS sit on a bed which is below sea level and slopes downward inland.[A] This slope, and the low isostatic head, mean that the ice sheet is theoretically unstable: a small retreat could in theory destabilize the entire WAIS leading to rapid disintegration. Current computer models do not include the physics necessary to simulate this process, and observations do not provide guidance, so predictions as to its rate of retreat remain uncertain.

  5. In reply to #2 by sbooder:

    In reply to #1 by aquilacane:

    The several hundred years part is why nothing will happen.

    Can I qualify something please?

    When you say “nothing will happen”, do you mean, nothing will be done about it, or do you mean, there will be no consequence?

    Sorry, I mean nothing will be done about it.

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