Feeling the heat: why the South Pole is warming up so quickly

Image credit: Andrew Mandemaker, Wikimedia commons, CC BY-SA 2.5

The South Pole is one of the coldest and most remote regions on our planet. It is a polar desert of long and sunless winters, quasi-continuous frigid winds, and precious little wildlife or vegetation. But as distant and inaccessible as it may be, it is not so isolated that it is exempt from the changes in our climate that have so ravaged the Earth in recent years.

The Antarctic Plateau – within which the geographic South Pole lies – regularly records temperatures lower than anywhere else on the planet. The average ranges from -60C in winter to -20C in summer, and the lowest natural air temperature ever recorded on Earth was done so at the Vostok Station in Princess Elizabeth Land (-89.2C, recorded in January 1983). Thus it is no surprise that much of this region is ice –indeed, 98% of the continent is covered by the Antarctic sheet, and almost 90% of the world’s ice is found here. The consequences of even a small percentage of this unfathomable mass of ice melting would be catastrophic for the entire planet – and yet this is precisely what is at risk of soon occurring. 

A recent study published in Nature Climate Change (2020) found that in the last 30 years, the South Pole has warmed three times faster than the rest of the planet, at around 0.6C per decade. This is alarming in and of itself, but is also somewhat of a surprise to many scientists. It was widely thought that the South Pole would remain isolated and cool even while the rest of the continent heated up, as, during the 20th century, the South Pole was actually cooling down, despite the surrounding areas of West Antarctica and the Antarctic Peninsula warming as expected. 

Nowhere on Earth is immune to climate change.

So what has caused this dichotomy in the South Pole’s temperatures? The answer, perhaps surprisingly, lies in the tropics: in particular, in a phenomenon called the Interdecadal Pacific Oscillation (IPO). The cycle of the IPO spans some 15-30 years, and alternates between a ‘positive’ and a ‘negative’ state. In the former, the tropical Pacific is hotter than average, and the northern Pacific is colder; in the latter, this is reversed. The IPO entered a negative cycle in the beginning of the 21st century, meaning there were greater convection and pressure extremes at high latitudes, generating strong flows of warm air over the South Pole. The physical mechanisms behind the IPO are not yet fully understood, due to the complexity of the interactions between elements of the climate system, but it is thought to be driven by a combination of advection by changing sea surface temperature (SST), Rossby wave adjustment, or some sort of air-sea coupling process. Whatever the driving force, though, one thing is clear: the South Pole is no longer exempt from global warming. 

Another point in the study, however, was the warning that, although the warming at the pole is of natural origins primarily, it has been intensified exponentially by human-caused climate change. The study warns that the combination of these factors “have worked in tandem to make this one of the strongest warming trends on Earth”. The message is thus: nowhere on Earth is immune to climate change. The planet is hot, and only getting hotter, and, if we do nothing to counteract it, there may well be no going back.

Written by Heather Jones and edited by Ailie McWhinnie.

Heather’s thoughts… The fact that different pockets of the Earth are affected differently by climate change did not overly surprise me to learn about, but the fact that we are experiencing accelerated warming in the region of the world that contains 90% of its ice? That is terrifying. It sounds like the introductory sequence of a disaster movie. And yet it is happening, and no-one talks about it. How much more inaction can governments excuse? This our home and it is melting. The seas are full of our plastics and our pollution, and they are rising as surely as the temperature is. How much more can the planet take? 

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