Climate change Antarctica has just lost ice the size of Argentina - during what is now winter!

[Maciamo]

Those of you who follow me on Twitter/X might already have seen this a few days ago. Now the highly reputed Economist magazine has published an article about it: The rapid loss of Antarctic sea ice brings grim scenarios into view

Ice melts in summer and water freezes again in winter. That's the natural cycle of Earth. Except that what we are seeing this year. It is now the middle of winter in Antarctica and the ice sheet keeps receding when it should be advancing.

With climate change, over the last 2 or 3 decades we have seen a slight but progressive shift year after year towards the sea-ice not regenerating as much in winter as it melted in summer. But until now the ice always came back in winter. 2023 is the first year when this is not happening, and this could indicate a radical change for the future of sea levels.

The Economist: "Compared with the average for that date in 1981-2010, its area was 2.84m km2 smaller—a gap as large as Argentina or Kazakhstan."

The surface air temperature is between +4 and +7.5°C higher than normal for the season. That's huge. Remember that we are barely at +1.5°C above normal temperatures globally. Of course global warming affects the poles and higher latitudes more strongly than the rest of the planet, as witnessed by the searing high temperatures in Canada in June that caused widespread forest fires, even in the north of the country where the climate is subarctic!

If the trend continues in Antarctica, and I don't see why it would reverse when it has only been accelerating, then sea levels could rise much faster and much more suddenly than previously expected.

 

[Maciamo]

Digging a bit deeper in this worrying piece of news about Antarctica, I found this article from the New Scientist. This situation is far more dire than what The Economist explained.

"For instance, in March 2022 temperatures up to 38.5°C higher than normal were recorded on the ice sheet 3 kilometres above sea level in the interior of East Antarctica – the most extreme anomaly seen on Earth. If this kind of event hit England in summer, the temperature in London would reach 60°C (140°F), says Siegert.

Because it is usually around -50°C in March in this part of Antarctica, it didn’t get above freezing, but if this kind of anomaly occurred during the continent’s summer, it would cause ice to melt deep in the interior, he says. The immediate cause was a river of warm, moist air from Australia. Normally, the circular winds around Antarctica, known as the polar vortex, keep out warm air from the north, but in this case the warm air penetrated deep into the interior, says Siegert."

That was last year, but as we have seen (e.g. in the article from The Economist above) 2023 is much warmer than 2022 globally, and even more so in Antarctica. I suppose that it's hard to tell as there simply isn't enough meteorological stations spread around the polar continent that is larger than Europe but only has a few scientists monitoring it. So things could be happening without us noticing it.