Antarctic sea-ice expansion in a warming climate confounds model predictions

Posted: April 23, 2022 by oldbrew in atmosphere, Carbon cycle, climate, modelling, Natural Variation, research, satellites, sea ice
Tags: , ,

Antarctic sea ice [image credit: BBC]


The obvious conclusion would be that the climate models are wrong, due to application of incorrect climate theory. As usual, researchers cast around desperately for other alternatives, only to find natural variation preventing warming from being global.
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Antarctic sea-ice has expanded over the period of continuous satellite monitoring, which seemingly contradicts ongoing global warming resulting from increasing concentrations of greenhouse gasses, says Phys.org.

In a study, published in Nature Climate Change, an international team of scientists from the University of Hawaiʻi at Mānoa, National Oceanic and Atmospheric Administration (NOAA) and South Korea shows that a multi-decadal swing of the tropical sea surface temperatures and its ability to change the atmospheric circulation across large distances is in large part responsible for the observed sea-ice expansion since the late 1970s.

Sea ice, which covers a substantial portion of the ocean surface in the polar regions, plays an important role in controlling global temperatures by reflecting incoming solar radiation. Decreases in sea-ice coverage, therefore, are expected to amplify greenhouse gas-induced global warming.

Changes in sea ice also affect energy exchanges between the ocean and atmosphere, carbon uptake by the ocean, ecosystems and the thermohaline oceanic circulation.

It is of great importance to monitor long-term changes in global sea ice and to ensure that physical processes that lead to those changes are accurately depicted in climate prediction models.

Difference between computer model simulations and observations

Continuous satellite observations, which started at the end of the 1970s, indicate marked decreases in Arctic sea ice over the satellite era, which is consistent with the global warming trend. In contrast, small but increasing trends have been observed, especially over the period 1979–2014, in the Southern Hemisphere.

Furthermore, while climate models are able to broadly reproduce the observed Arctic sea-ice decreases, the majority of them are not able to capture the Antarctic sea-ice expansion over the period 1979–2014.

“The observed Antarctic sea-ice expansion and model-observation discrepancy have perplexed climate scientists over more than a decade,” said lead author Eui-Seok Chung, from the Korea Polar Research Institute.

“Various hypotheses, such as increased freshwater fluxes due to sub-ice shelf melting, atmospheric and oceanic circulation changes associated with human-induced stratospheric ozone depletion and tropical teleconnections, have been proposed to explain the observed Antarctic sea-ice expansion, but the issue has remained as one of the biggest challenges in climate science,” said professor Axel Timmermann, director of the IBS Center for Climate Physics at Pusan National University, and co-author of this study.

The observed Antarctic sea-ice changes are caused not only by increasing concentrations of greenhouse gasses and/or stratospheric ozone depletion, but also linked to natural variability of the climate system, which occurs without direct connections with human activities.

Full article here.

Comments
  1. ivan says:

    I have to ask, ‘what warming world’? There was more snow down here (the south of France) two nights ago.

    It might help if these so called ‘scientists’ actually got out of their ivory towers and walked the real world to see what is happening. They might realise that the climate is a chaotic system that can never be modelled on a logical computer system. Why do they keep on trying to do the impossible?

  2. Gamecock says:

    An international team of scientists tells us decreases in Arctic sea ice is consistent with the global warming, and increases in Antarctic sea ice is consistent with global warming.

    You don’t have to be an international team of scientists to have cognitive dissonance, but it helps.

  3. […] Antarctic sea-ice expansion in a warming climate confounds model predictions […]

  4. oldbrew says:

    They often say natural variation ‘masks’ what’s going on, but it IS what’s going on.

  5. oldbrew says:

    Sea ice, which covers a substantial portion of the ocean surface in the polar regions, plays an important role in controlling global temperatures by reflecting incoming solar radiation.

    At high latitudes not much solar radiation can penetrate the water surface, and there’s almost none in the long winter anyway, which is why there’s sea ice there in the first place.

  6. Philip Mulholland says:

    When the world’s solar energy driven weather machine acquires more thermal energy in the tropics, the system responds by increasing the rate of convection overturning. Consequently both the Hadley cell and also the co-linked Ferrel cell engage in an advection process that transports more air at altitude towards the poles.

    The polar icecap of Antarctica is the highest average elevation solid surface of any continent on Earth. Any increase in air mass convection down-welling in the polar vortex (yes I got that right) on to the icecap strengthens the radiative generation of cold surface katabatic winds. These gravity flows of super cooled air flood off the icecap and generate enhanced sea ice formation during the austral winter.
    Simples.

  7. Phil Salmon says:

    a multi-decadal swing of the tropical sea surface temperatures … is in large part responsible for the observed sea-ice expansion since the late 1970s.

    Are they sure they have the arrow of causality going the right way? I would say the reverse is more likely – Antarctic cooling disrupting global including tropical circulation patterns.

  8. oldbrew says:

    They have to cover their confusion and disappointment somehow, but the message doesn’t impress.

  9. Stephen Richards says:

    as usual, a lot of bull and no evidence

  10. JB says:

    double think not cog-dis. These definitely have no dissonance in their thinking.

  11. Phoenix44 says:

    If you build a model and it predicts only some of what happens and gets the rest wrong, it is fallacious to assume your model is part correct. It is quite possible it is all wrong. To then tweak that model to get the wrong bits right is stupidity.

  12. oldbrew says:

    All models are wrong.

    https://en.wikipedia.org/wiki/All_models_are_wrong

    But climate science doesn’t go about correcting the wrongness of radiative gas theory, just tries to justify it by pointing to the natural variation it doesn’t really believe in.

  13. Gamecock says:

    JB, a distinction without a difference.

  14. oldbrew says:

    Earth’s natural variation…

    Antarctica: 85,000 earthquakes caused by underwater volcano
    29 Apr 2022

    Scientists think they have discovered the mystery behind why 85,000 earthquakes hit Antarctica in 2020.

    Experts believe they were all caused by a previously dormant underwater volcano called “Orca Seamount” which has awakened.

    The volcano is found deep under the sea near King George Island and some of the quakes were felt by scientists working there in research stations.

    The event was the strongest earthquake activity ever recorded in Antarctica.

    https://www.bbc.co.uk/newsround/61270297

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