Another wake-up call in Antarctica

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This article was published 14/08/2023 (799 days ago), so information in it may no longer be current.

WE hear a lot about climate wake-up calls. Here’s one you would do well not to ignore: Antarctica had the most extreme heat wave ever recorded.

In March 2022, east Antarctica saw temperatures of up to 38.5 C higher than average for the time of year. A so-called “atmospheric river” brought warm air and moisture from Australia into the heart of the frozen continent, raising temperatures to -10 C (14 F) from the norm of -50 C (-58 F). Had the U.K.’s 2022 heat wave — which saw the nation exceed 40 C for the first time — been that severe, we would have hit 60 C.

It’s just one of many extreme events brought together in a new report published in the journal Frontiers in Environmental Science. What Antarctica’s future looks like is uncertain, but one sure thing is that continued fossil-fuel burning puts the world’s southernmost continent at increased risk of catastrophic cascades. The extreme heat in 2022, for instance, led to surface warming of land ice, the breaking up of sea-ice and the subsequent collapse of the Conger Ice Shelf — a frozen platform the size of Rome.

Other events noted include record low sea ice levels, marine heat waves and unprecedented surface melting. In terms of sea ice extent, this year has been particularly unusual. July’s sea-ice levels were three times further from the average than what had ever been seen previously. These events are detrimental to Antarctica’s iconic wildlife: between 2018 and 2022, 42 per cent of emperor penguin colonies likely experienced total or partial breeding failure due to fast ice breakup in at least one year.

These are arguably climate-related tipping points — when something goes beyond the point of no return — already happening in the South Pole. When we see large icebergs shear off from the continent, large ice shelves collapsing and sea ice area reducing, what might not be appreciated is that these things cannot easily be fixed, if at all. Anna Hogg, co-author and associate professor in the School of Earth and Environment at the University of Leeds, says that we’ve never seen an ice shelf recover in our lifetimes.

Irreparable losses in one of the most precious and unique areas on Earth are devastating and an ugly legacy for mankind’s actions. That’s reason enough to prevent further degradation where possible. But there’s another reason to worry. As Jane Rumble, co-author from the study and head of the Polar Regions Department for the U.K.’s Foreign and Commonwealth Office, told journalists before the report’s release, “What happens in Antarctica, does not stay in Antarctica. It has global consequences.”

Take sea levels, for example. Today, thanks to fossil-fuel burning, the Antarctic ice sheet contributes six times more mass to the ocean than it did three decades ago. The reservoir of ice on Antarctica’s ice sheet is vast — if it were to melt completely, which scientists don’t expect will happen anytime soon, it would raise global sea levels by 57 metres on average. Unlike the glaciers that would melt and then stop contributing to sea level rise, Antarctica would keep going and going — posing challenges that may be existential for some low-lying regions and coastal population centres, from Jakarta to Miami.

The other fear is that Antarctica stops being our planet’s refrigerator and starts acting more like a radiator. At the moment, Antarctica’s ice reflects a large amount of solar radiation back into space, helping keep the world cool.

Only 0.2-0.4 per cent of the continent is exposed above the ice at the moment, but that proportion is likely to increase with further warming. That reduces the albedo — or reflectivity — of the surface and increases the heat absorbed by the planet. It’s an effect we’re already seeing in the Arctic, which is now warming four times faster than the rest of the planet. If Antarctica starts acting like the Arctic, that would have grave consequences for everywhere else.

It might be many thousands of miles away, but you can bet that we’ll all feel the effects of a changing Antarctica. Just one more reason to add to the library of justifications for rapid and bold climate action.

Lara Williams is a Bloomberg Opinion columnist covering climate change.