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Earth NASA Science

Glacial Melting In Antarctica May Become Irreversible, NASA-Funded Study Suggests (theguardian.com) 327

An anonymous reader quotes a report from The Guardian: A Nasa-funded study found instability in the Thwaites glacier meant there would probably come a point when it was impossible to stop it flowing into the sea and triggering a 50cm sea level rise. Other Antarctic glaciers were likely to be similarly unstable. The Thwaites glacier, part of the West Antarctic ice sheet, is believed to pose the greatest risk for rapid future sea level rise. Research recently published in the Proceedings of the National Academy of Sciences journal found it was likely to succumb to instability linked to the retreat of its grounding line on the seabed that would lead to it shedding ice faster than previously expected.

The researchers found a precise estimate of how much ice the glacier would shed in the next 50 to 800 years was not possible due to unpredictable climate fluctuations and data limitations. However, 500 simulations of different scenarios pointed to it losing stability. This increased uncertainty about future sea level rise but made the worst-case scenarios more likely. A complete loss of the West Antarctic ice sheet would be expected to increase global sea levels by about five meters (16ft), causing coastal cities around the world to become submerged.

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Glacial Melting In Antarctica May Become Irreversible, NASA-Funded Study Suggests

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  • Well (Score:5, Interesting)

    by Dunbal ( 464142 ) * on Wednesday July 10, 2019 @10:35PM (#58905862)
    Irreversible until the next ice age, at least.
    • by Truth_Quark ( 219407 ) on Thursday July 11, 2019 @01:52AM (#58906326) Journal
      The world has gone through long periods of time where there is not ice sheets at the poles.

      Ss there's no reason to assume that there will be another glaciation. The last time CO2 levels were as high as today, there were trees at the south pole. [theguardian.com]

      Unless there's something really important that we don't understand, we are at the start of a long melt, that will not reverse.
      • Unless there's something really important that we don't understand

        CO2 levels are associated with higher temperatures but in the fossil record they follow the temperature pulse; they don't precede it.

        This is as a theory of a vibrant biosphere would predict.

      • Unless there's something really important that we don't understand, we are at the start of a long melt, that will not reverse.

        This is true, if human actions don't change. For better or worse, humans are now the ones in control of the geology of the earth. It is entirely possible that we will change our course of action and actually address the climate crisis.

        Or not. There are still plenty of people who refuse to admit that climate change is real, let alone who are willing to accept even the slightest inconvenience to themselves to address it.

  • by phantomfive ( 622387 ) on Wednesday July 10, 2019 @11:10PM (#58905974) Journal
    According to their model (and a technique from statistical physics).
  • But this guy is tweeting so much stuff that it might have been a coincidence that he was right.
  • I've been wondering (Score:2, Interesting)

    by Sqreater ( 895148 )
    If there is a growing blanket of CO2 over the Earth and the Earth is heating as a result, what does that do to the rate of diffusion of heat from the core of the Earth to space? And do the ice-covered poles act to draw heat from the mantle and core? Are they heat sinks? If they are, and that is significant, what would be the expected result of the pole ice melting? Would that result in more volcanic eruptions? Could we expect more earthquake activity? Would that add significantly to the energy of weather?
    • by religionofpeas ( 4511805 ) on Thursday July 11, 2019 @02:58AM (#58906476)

      If there is a growing blanket of CO2 over the Earth and the Earth is heating as a result, what does that do to the rate of diffusion of heat from the core of the Earth to space?

      The heat of the core diffuses to the surface, and gets combined with the surface heating from the Sun. At that point it doesn't really matter where the heat was coming from. All that matters is the total amount.

      The energy from core to surface is about 47 TW.

      The energy from Sun to surface is about 173000 TW.

      As you can see, geothermal energy is an insignificant contributor.

      • Re: (Score:2, Interesting)

        by Sqreater ( 895148 )

        If there is a growing blanket of CO2 over the Earth and the Earth is heating as a result, what does that do to the rate of diffusion of heat from the core of the Earth to space?

        The heat of the core diffuses to the surface, and gets combined with the surface heating from the Sun. At that point it doesn't really matter where the heat was coming from. All that matters is the total amount.

        The energy from core to surface is about 47 TW.

        The energy from Sun to surface is about 173000 TW.

        As you can see, geothermal energy is an insignificant contributor.

        Is the 17300 TW the energy staying at the surface of the Earth? Does that include reflected energy according to the albedo of the Earth? In any case, the contribution to surface effects of 47 TW would seem to be negligible.

        • by religionofpeas ( 4511805 ) on Thursday July 11, 2019 @03:50AM (#58906650)

          Is the 17300 TW the energy staying at the surface of the Earth

          Sorry, the 173000 TW is the energy hitting top of atmosphere. About 88000 TW is left to heat the surface, the rest is reflected back.

          The 88000 TW is not staying there. It is radiated into space as infrared light. The greenhouse effect is caused by CO2 blocking a bit of this escaping energy, which then results in surface warming until a new balance is achieved.

    • As to the volcanic activity; the pressure from large ice sheets acts as a damper -- research into just this phenomenon revealed a 5-fold increase in earthquakes and volcanoes following ice ages. But we don't have any data on ice sheets coming off this quickly. Probably going to be more than a 5-fold increase in the areas that used to have a few billion tons of ice on them.

    • by geekoid ( 135745 )

      "If "

      Its not an 'if' its testable, and had been tested, and it's not even hard to test.

      Pole melting will create a sharp rise in temperature, rising ocean levels,

      Yes, it's likely there will be more geological activity because the weight distribution of the water will change. However, this is one of the least worrying issues of AGW.

      Yes, the weather is already more significant, plus the atmosphere has more moisture, so we will see an increase in the extremes.

      My replies are simple, and l intended to inform and

  • It's one of the core properties of ice to disappear when melting.

  • by RogueWarrior65 ( 678876 ) on Thursday July 11, 2019 @09:22AM (#58907488)

    There is no such thing as a stable glacier.

Some people manage by the book, even though they don't know who wrote the book or even what book.

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