Historically, the Antarctic has a cooling effect on the planet because this huge mass of white ice reflects the sun’s rays back into the atmosphere helping to keep the planet cooler. However, an area of sea ice the size of Greenland is missing on the Antarctic continent. The numbers are vast. The current area of the Antarctic continent is on average 2,400,000 km² less than the 1979-2022 average.
And the reduction in ice cover means that the continent is less able to reflect sunlight.
Prof Martin Siegert from the University of Exeter, said that “a lot of solar radiation is bounced back out into space, just reflected off the white surface”. But when that vast white area is reduced and you’re left with darker seawater the reflecting ability is reduced and the earth absorbs heat.
Siegert and colleagues published a paper in the journal Frontiers in Environmental Science in which they document what appears to be a range of extreme events in the Antarctic.
They include:
- Increased breakup (calving) of icebergs;
- loss of sea ice;
- massive temperature anomalies.
In 2022, parts of East Antarctica were 40°C higher than normal which was due to a change in air currents which in turn brought warmer weather from Australia.
He believes that the heat wave last year produced “the largest heat wave that the earth has ever experienced in terms of the variance from the normal”.
The consequences were that regions that were expected to be -50°C were instead -10°C.
There have been large losses of ice shelves which form where glaciers meet the sea. Anna Hogg, of the University of Leeds, said that “It’s going to take decades, if not centuries, but these things to recover. There is no quick fix to replacing this ice.”
The current anomaly in ice cover on the Antarctic is far outside the normal variability seen in ice cover over previous years. Anna Hogg believes that this is due to global warming. She said “I think it’s perfectly scientifically reasonable to make the assumption that it is linked to our heating planet.”
She added that “There Is a real danger, I think in the years coming ahead that Antarctica starts to behave in a way that looks a lot more like the Artic, and we start to see that it stops acting as a refrigerant for the planet, and it starts acting as a radiator for the planet.”
