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Earth

Antarctic Sea Ice on Cusp of Record Winter Low For Second Year Running (theguardian.com) 28

Sea ice surrounding Antarctica is on the cusp of reaching a record winter low for a second year running, continuing an "outrageous" fall in the amount of Southern Ocean that is freezing over. From a report: The Antarctic region underwent an abrupt transformation in 2023 as the sea ice cover surrounding the continent crashed for six months straight. In winter, it covered about 1.6m sq km less than the long-term average -- an area roughly the size of Britain, France, Germany and Spain combined. Scientists at the Australian Antarctic Program Partnership said the latest data showed this had been repeated in 2024. On 7 September the amount of frozen ocean was less than on the same date last year. While the winter record is not yet complete, and it is therefore not clear if the extent of sea ice for the season will be less than last year, the scientists said it was part of a body of evidence that the Antarctic system had moved to a "new state."

"What we're really talking about are two incredible extreme events," said Dr Will Hobbs, a sea ice researcher at the University of Tasmania. "Last year was outrageous and it's happened again." Hobbs said at monthly and yearly timescales the atmosphere was the main driver of regional variability. "What's different now is that warmer Southern Ocean temperatures are really having an impact on the sea ice," he said. "We know that the past two years have been the warmest on record for the planet, with global temperatures more than 1.5C above pre-industrial for extended periods. This global warmth is now reflected in the oceans around the Antarctic." On Saturday, Southern Ocean sea ice covered 17m sq km, less than the previous low of 17.1m sq km last year. The long-term average for 7 September based on satellite data is 18.4m sq km.

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Antarctic Sea Ice on Cusp of Record Winter Low For Second Year Running

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  • by Baron_Yam ( 643147 ) on Tuesday September 10, 2024 @10:24AM (#64777031)

    The atmosphere is massive (citation needed?)

    Increase the insulation with more CO2, it takes a while to heat up the air. And the air is transferring heat to the oceans which are even more massive.

    It takes time to heat them up, even using a giant multi-billion year fusion bomb exploding only a few light-minuted away.

    The flip side is... Remove that insulation and it'll take just as long to cool down. If we're seeing global warming causing extreme melt in the antarctic, it's going to continue to get worse. And as it does, there's less ice to reflect sunlight back into space before it is converted into heat. Which will cause more moisture in the air to trap even more heat. People have earned PhDs tracing all the various feedback mechanisms and they're all pointing to 'hotter'.

    • They pointed to BOE in the Arctic as the same as adding 25 years of emissions (trillion tons CO2)

      I hate to think what the Antarctic ocean (note: not the Antarctic itself, but the ocean), which is far closer to the equator and much more sunlight throughout the year will do as an additional emissions equivalent.

      Iâ(TM)m guessing about 75 years equivalent warming if it goes ice free in the winter. 3 trillion tons CO2.

      And itâ(TM)s not an all or nothing feedback loop. Last year it was almost 2,000,000

    • by hey! ( 33014 )

      Well, yes the atmosphere is massive, but it receives an enormous -- in fact truly staggering -- quantity of solar energy.

      None of which is here nor there as far as I can see, because we're talking about *winter* polar sea ice changes. The polar regions receive very little solar energy in the winter, and changes in Antarctic winter sea ice extent are, I more a matter of changes in wind patterns than air temperatures.

      Those wind changes, however, are likely related to AGW mediated changes in the jet stream.

      • by hey! ( 33014 )

        Just to clarify -- those "anomalously warm" temperatures in the antarctic are still very cold; cold enough to form sea ice. They're just indicative of unusual weather patterns which *may* include unusual wind conditions that could affect sea ice extent.

  • Why measure area in milli-square-kilometers [nist.gov]?
  • by cmarkn ( 31706 )
    So what does this mean? Ice floating on the ocean doesn't affect sea level. It's not generating food for sea life or affecting oxygen or co2 levels. What difference does it make if there's less ice?

To avoid criticism, do nothing, say nothing, be nothing. -- Elbert Hubbard

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