UK homes could be at risk of flooding if Antarctica becomes ‘global radiator’ and ice melts
Antarctica is at risk of becoming a “global radiator”, with the current rate of ice loss at the upper bounds of previous forecasts, scientists have warned.
The southern continent currently acts to cool the global climate by reflecting large amounts of solar radiation with its pure white surface. The melting of ice, and loss of that surface, means it could begin to absorb heat instead.
Melting ice also means that 16 million more people, including in the UK, could be exposed to flooding every year.
The warning came alongside the publication of a major synthesis paper pulling together Antarctic scientific research from the last several years to paint a continent-wide picture.
Antarctica is currently experiencing record-low sea ice, despite being in the depths of midwinter, while in March 2022 it experienced temperatures 38°C above the seasonal average, pushing the mercury to just -10°C.
Jane Rumble, head of the polar regions at the Foreign Office, said that the public should be deeply concerned by what was happening in Antarctica because it “drives the planet, so what happens in Antarctica does not stay in Antarctica. It has global consequences.”
Martin Siegert, a glaciologist at the University of Exeter, said people should be concerned. “There’s a real danger I think in the years ahead, that Antarctica… stops acting as a refrigerant for the planet and it starts acting as a radiator for the planet.”
At present, Proessorf Siegert said, Antarctica reflects large amounts solar energy back out into space but if it were to darken, as the Arctic has, that effect would be diminished or lost.
This happens in several ways. Sands and gravels exposed by retreating ice are blown onto the remaining ice and darken its surface, while surface meltwater and ice-free oceans are also substantially darker than ice, increasing the energy absorbed.
All these processes have already been documented in the Arctic where they have created a feedback loop that has contributed to it becoming the fastest-warming part of the planet.
Another reason to be worried, he said, was because it was storing “colossal” amounts of ice, even a fraction of which would send sea levels soaring if it melted.
Already, ice loss from the Antarctic was running at the upper limits of what scientists had forecast, said Professor Anna Hogg of the School of Earth and Environment at the University of Leeds.
That is unusual and suggests that the models may have been too conservative in their estimates.
“The observations show we’re tracking the most extreme prediction of what might happen. So it’s within the bounds of what’s been predicted, but we weren’t really expecting the observations to show that we’re meeting the extreme end of those scenarios. And the question is, is that going to continue or get worse going forward,” said Professor Hogg.
Moreover, any ice that is lost is almost impossible to get back, she said, making it all the more urgent that climate change be held in check.
If ice loss continues at its present rate, the annual rise in sea levels will grow from 1.8cm a year to 17cm a year by the end of the century, she said. By that point, the paper said, sea levels would have risen by over a metre.
In all, it will expose as many as 16 million more people to annual coastal flooding, making storm surges considerably worse.
Until around 2016, Antarctic ice had been relatively stable, with most of the sea ice loss happening in the Arctic. That is no longer the case, however, and Antarctica is beginning to replicate patterns already seen at the northern pole.
Most of the sea level rise experienced by the planet so far has been from warmer water expanding, alongside the melting of the earth’s approximately 300,000 glaciers.
In future, the rise in sea levels will be driven almost exclusively by ice lost from Antarctica and Greenland, the scientists said.
Such is the amount of frozen water contained in Antarctica that even with very high levels of global warming, it will retain ice for centuries yet, meaning that it can keep raising sea levels indefinitely.
If all the ice on Antarctica were to be lost, something highly unlikely to happen in the next hundred years, it would cause sea levels to rise by an average of 57 metres.
