Rapid loss of Antarctic sea ice may be climate tipping point, new study reveals
The study gathered data from observations, ice cores and ship logbooks to chart long-term changes in the area of sea ice, putting into context a rapid decline in recent years.
'A regime shift has reduced Antarctic sea-ice extent far below its natural variability of past centuries, and in some respects is more abrupt, non-linear and potentially irreversible than Arctic sea-ice loss,' it said, referring to melting at the North Pole.
Changes are having knock-on effects across the ecosystem that in some cases amplify one another, Nerilie Abram, the study's lead author, said.
A smaller ice sheet reflects less solar radiation, meaning the planet absorbs more warmth.
And it will probably accelerate a weakening of the Antarctic Overturning Circulation, an ocean-spanning current that distributes heat and nutrients and regulates weather.
Loss of ice is increasingly harming wildlife including emperor penguins, who breed on the ice, and krill, which feed below it.
And warming surface water will further reduce phytoplankton populations that draw down vast quantities of carbon from the atmosphere, the study said.
'Antarctic sea ice may actually be one of those tipping points in the Earth's system,' said Ms Abram, a former professor at the Australian National University (ANU) and now chief scientist at the Australian Antarctic Division.
Reining in global carbon dioxide emissions would reduce the risk of major changes in the Antarctic but still may not prevent them, the study said.
'Once we start losing Antarctic sea ice, we set in train this self-perpetuating process,' Ms Abram said.
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Irish Independent
a day ago
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Rapid loss of Antarctic sea ice may be climate tipping point, new study reveals
The paper in the journal Nature aimed to describe in previously unseen detail the interlocking effects of global warming on the Antarctic, the frozen continent at the planet's South Pole. 'Evidence is emerging for rapid, interacting and sometimes self-perpetuating changes in the Antarctic environment,' it said. The study gathered data from observations, ice cores and ship logbooks to chart long-term changes in the area of sea ice, putting into context a rapid decline in recent years. 'A regime shift has reduced Antarctic sea-ice extent far below its natural variability of past centuries, and in some respects is more abrupt, non-linear and potentially irreversible than Arctic sea-ice loss,' it said, referring to melting at the North Pole. Changes are having knock-on effects across the ecosystem that in some cases amplify one another, Nerilie Abram, the study's lead author, said. A smaller ice sheet reflects less solar radiation, meaning the planet absorbs more warmth. And it will probably accelerate a weakening of the Antarctic Overturning Circulation, an ocean-spanning current that distributes heat and nutrients and regulates weather. Loss of ice is increasingly harming wildlife including emperor penguins, who breed on the ice, and krill, which feed below it. And warming surface water will further reduce phytoplankton populations that draw down vast quantities of carbon from the atmosphere, the study said. 'Antarctic sea ice may actually be one of those tipping points in the Earth's system,' said Ms Abram, a former professor at the Australian National University (ANU) and now chief scientist at the Australian Antarctic Division. Reining in global carbon dioxide emissions would reduce the risk of major changes in the Antarctic but still may not prevent them, the study said. 'Once we start losing Antarctic sea ice, we set in train this self-perpetuating process,' Ms Abram said.
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7 days ago
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Industry initially grumbled (of course), warning of costs and inconvenience, but quickly pivoted to invent safer alternatives. The chemical companies that had made fortunes from CFCs soon made fortunes from the replacements. It was, in its way, capitalism at its most adaptable. The long, slow healing Fixing the ozone hole was never going to be instant. CFCs are stubborn chemicals, hanging around in the atmosphere for 50 to 100 years. Even after production stopped, the stockpiles we'd already released were still floating upwards to do their damage. The ozone layer, battered for decades, needed time to recover. The Ozone 'hole': This satellite image was obtained by the NASA Total Ozone Mapping Spectrometer (TOMS). It is centred on the South Pole where the so-called ozone 'hole' was first observed by the British Antarctic Survey in the mid-1980s. This was achieved through measurements from the land base at Halley Bay using a device to measure ozone UV absorbance. Pic: NASA 2018 But something remarkable happened: it started working. By the early 2000s, scientists detected the first signs that ozone levels were stabilising. In 2018, NASA confirmed the hole was shrinking, and that it wasn't just due to natural fluctuations, but because the Montreal Protocol was working exactly as intended. By 2023, scientists reported that the Antarctic ozone hole was on track to heal completely by the mid-21st century. An accidental climate bonus The Montreal Protocol didn't just protect the ozone layer, it also delivered an unexpected climate win. CFCs are not only ozone-destroyers; they're also powerful greenhouse gases, thousands of times more potent than CO₂ at trapping heat. By phasing them out, the treaty avoided an enormous amount of future warming. So, in a strange twist, the effort to protect us from UV rays also gave us breathing room on carbon emissions. Though sadly, we've used that room to keep emitting CO₂ at record levels. 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