Why is the South Pole warming 3 times faster than the rest of the planet?

Like the Arctic, but for different reasons, Antarctica is subject to an acceleration of its warming. The causes are natural, but increased by human-caused climate change.

In June 2020, Siberia reached a new temperature record, reaching 38 degrees Celsius. This peak was not in itself a surprise, since it is the result of a strong heat wave that has affected the Arctic Circle since January. There is now more and more evidence that the Arctic is at the heart of accelerated warming: the North Pole is warming twice as fast as the rest of the planet. Scientists have been concerned for several years about more repeated and longer heat waves in this polar region.

An international research work, published in Nature Climate Change this June 29, 2020, shows that Antarctica is experiencing an equally strong heat wave. ” Over the past 30 years, the South Pole has experienced statistically record warming [entre 0,61 et 0,34 degré Celsius] per decade, which is more than three times the world average “Writes this group of New Zealand, British and American researchers.

Natural and human causes

This record warming is mainly due to an anomaly (a fluctuation which moves the regional climate from a stable / average state) over a large portion of the Southern Ocean (Antarctic Ocean), the result of which is the increase surface temperatures throughout the western tropical Pacific. This anomaly means that at altitude, the pressure increases, and therefore the air flow over the South Pole becomes warmer. It is a phenomenon known to climatologists under the name of “decennial oscillation of the Pacific”. It works in cycles: every 15 to 30 years, the tropical Pacific becomes warmer and the North Pacific colder (negative cycle), then it reverses (positive cycle). At the beginning of this century, we entered a negative cycle.

This region of the planet is therefore constantly subject to fluctuations in its temperatures. The authors of the study published in Nature Climate Change explain that these extreme changes in temperature every few decades tend to mask the total impact of human activities on this region. But this impact is very present: climate change seems to intensify the magnitude of the natural fluctuations of the South Pole, and therefore increase its warming.

« It was suspected that this part of Antarctica could be immune / isolated from global warming. We found that this is no longer the case “Kyle Clem, co-author of the study, told AFP. ” Although global warming is part of the natural variability of climate models, it is very likely that human activity has contributed. The impact of humans on Antarctica is observed by different metamorphoses more exceptional than normal, such as the melting of the ice on the coasts or the massive increase in green algae caused, among other things, by our carbon emissions .