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Why Antarctica Is Getting Taller (livescience.com)

Posted by BeauHD on from the growing-like-a-weed dept.

An anonymous reader quotes a report from Live Science: Bedrock under Antarctica is rising more swiftly than ever recorded -- about 1.6 inches (41 millimeters) upward per year. And thinning ice in Antarctica may be responsible. That's because as ice melts, its weight on the rock below lightens. And over time, when enormous quantities of ice have disappeared, the bedrock rises in response, pushed up by the flow of the viscous mantle below Earth's surface, scientists reported in a new study. These uplifting findings are both bad news and good news for the frozen continent. The good news is that the uplift of supporting bedrock could make the remaining ice sheets more stable. The bad news is that in recent years, the rising earth has probably skewed satellite measurements of ice loss, leading researchers to underestimate the rate of vanishing ice by as much as 10 percent, the scientists reported. The findings were published in the journal Science.

5 of 62 comments (clear)

  1. Likely effect on surrounding plates? by Maxo-Texas · · Score: 5, Interesting

    Seems like this much mass moving would have an effect on the surrounding plates.

    It's currently subducting under the south american plate.
    Seems like it could snap off and cause tsunami's along thousands of miles of south american coast line.

    It interacts with six other plates in total.

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    1. Re:Likely effect on surrounding plates? by pk001i · · Score: 5, Informative

      Geophysicist here. Typically this sort of vertical place motion is slow. It is known as isostatic rebound, or post-glacial rebound, and it is pretty common. In fact, parts of north america and northern europe are still rebounding from when the glaciers melted after the last ice age. The uplift rate here is 41mm/year, which is high for this sort of thing, but it is not going have that great of an impact when you consider that the lithosphere (plate plus the upper solid mantle) is 50-150km thick. 41mm/ys is roughly the same rate fingernails grow. As far as I know an entire plate shearing off has never occcured, and seems pretty hard for me to imagine. Of the 6 plates it interacts with, 5 of those are ridges, where new plate is formed, and the last is a short section of subduction, where the antarctic plate is beaing pushed underneath the south american plate. Patagonian volcanoes are the result of this subduction, just like the volcanoes in the pacific northwest. While tsunamis can be generated here, they will happen the old fashioned way, where a large earthquake occurs and a small portion of the seafloor lifts up a bit.

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  2. Re: So, no Climate Warming? by ShanghaiBill · · Score: 3, Interesting

    Like the North American continent, Antartica is rising in response to the end of the last ice age.

    I don't think so. Antarctica is so cold that most moisture condenses and falls as snow over the floating ice pack, and little reaches the interior. Warming temperatures mean that more snow falls further inland, over continental ice, thickening the ice.

    TFA only measured the area around the Amundsen Sea in West Antarctica, which is warmer and closer to the coast than the much larger East Antarctic ice sheet.

  3. Re: So, no Climate Warming? by ole_timer · · Score: 4, Interesting

    According to Robert Rhode, a noted climate change PhD - "Even in the event of severe sustained warming, it would take many thousands of years for Eastern Antarctica to be fully deglaciated." - most of the ice is in the east.

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  4. Ohio is still rebounding from last ice age by laughingskeptic · · Score: 4, Interesting

    The extrapolations being made from this article are ridiculous. The idea that the small elevation increase will aid in slowing ice movement is simply disproportionate from reality. Ohio is still rebounding from the last ice age, this is a process that occurs over thousand year time spans. We are melting the ice magnitudes of order faster than the rebound can occur.

    If we manage to melt all of the ice on Antarctica for centuries, not only will Antarctica rise a mile, but the continents in the norther hemisphere will be sucked inwards so that the volume of the spheroid remains constant. Most of the southern and central US will once again be seabed in 100,000 years. If Antarctica is rising as fast as they say, then the sea floor of the northern Atlantic and Pacific are likely already sinking. Crust cannot rise in one place without compensation elsewhere. The volume of the earth has to remain constant.