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Earth Science

Why Antarctica Is Getting Taller (livescience.com) 62

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.
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Why Antarctica Is Getting Taller

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  • by Maxo-Texas ( 864189 ) on Thursday June 21, 2018 @05:52PM (#56825386)

    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.

    • by pk001i ( 649678 ) on Friday June 22, 2018 @12:22AM (#56826692)
      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.
      • by Anonymous Coward

        Great, someone with knowledge in the field. A chance to ask a question.

        If Antarctica rises, does something else shrink? E.g. does the sea floor around Antarctica get lower? I'm guessing so because earth is probably relatively incompressible. Also, if I'm squeezing an orange that's more or less what's happening there, too.

        If true, what's the effect on sea levels?

      • Thanks!

        I'm assuming that end of the higher plate will rise some too then?

  • 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.

    Given how my work days lately have seemed longer and longer, I was going to say that Earth is probably rotating more slowly and so assuming a more perfectly spherical shape.

    We can test my hypothesis by measuring to see if there is a corresponding subsidence at the equator.

  • by Anonymous Coward

    So now Antarctica wishes it was a baller?

  • by laughingskeptic ( 1004414 ) on Thursday June 21, 2018 @11:25PM (#56826550)

    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.

    • by Raenex ( 947668 )

      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.

      Did you notice the curiosity in your sentence? How do you know that "we" are melting the ice, as opposed to the ice continuing to melt from the last ice age? Sea levels rose [nasa.gov] about 400 feet in the last 10,000 years.

  • Aunt R.D. Caw is getting shorter as she gets older. Still kicks ass at bridge though. She says it's allll in the viscous mantle.
  • ...to this single article which focuses on Western Antarctica there are a number of recent scholarly articles, including findings by NASA ( https://principia-scientific.o... [principia-scientific.org] ), that show ice growth Eastern Antarctica that offsets the loss in the west for a net gain.

    Skew the data by not providing all the facts and you too can go full Chicken Little about anything. *smdh*

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