Mélanie Gomez with AFP / Photo credits: Adrian Wlodarczyk / Robert Harding RF / robertharding via AFP
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7:27 p.m., September 7, 2023
The warming of Antarctica, twice as high as in the rest of the world, is much greater than estimated by climate models, write researchers in a study published Thursday, after analyzing dozens of ice cores. Scientists based in France, Germany and the United Kingdom used data from 78 cores taken in Antarctica, making it possible to trace the evolution of the climate over 1,000 years. This method makes it possible to compensate for the lack of data from the white continent, where few weather stations are present and where satellite data are incomplete.
Results “20 to 50% greater than predictions from climate models”
Concerning warming in Antarctica, “the results we obtain are 20 to 50% greater than the predictions of climate models”, explains to AFP Mathieu Casado, from the Laboratory of Climate and Environmental Sciences, author principal of the study published in the journal Nature climate change. “With our reconstructions from ice cores, we predict a warming of between 0.22°C and 0.32°C per decade” for Antarctica, while “climate models predict a value of 0. 18°C per decade,” he specifies. Warming in Antarctica represents “practically twice the value of the global average”, he notes.
Climate change is more marked at the poles due to an already known phenomenon called polar amplification, with the melting of snow and ice that reflect sunlight. But Antarctica was theoretically much less affected by this phenomenon, insofar as it is made up of a thicker layer of ice.
Complex reasons for Antarctic warming
The warming of Antarctica would be due to complex reasons linked to the quality of the snow and “atmospheric circulation”, indicates Mathieu Casado. The authors conclude their study on the need for paleoclimatologists, statisticians and modellers to work together to reconcile models and observations concerning the poles.
But beyond that, Mathieu Casado wonders if climate models don’t also underestimate other phenomena, opening the door to other research. “This is not something that we were able to estimate in the study but a priori these are the same climate models used to evaluate future changes in sea levels, for example, according to gas emission scenarios greenhouse effect. So we wonder to what extent that will have an impact on these predictions too,” he says.