The South Pole has heated three times faster than the rest of the planet in the past 30 years due to the warmer temperatures of the tropical oceans, new research showed on Monday.
Antarctic temperatures vary widely by season and region, and for years the South Pole was thought to have remained cold even when the continent warmed up.
Researchers in New Zealand, Britain and the United States analyzed 60 years of weather station data and used computer models to show what was causing the accelerated warming.
They found that warmer ocean temperatures in the western Pacific had reduced atmospheric pressure over the Weddell Sea in the South Atlantic for decades.
This in turn had increased the flow of hot air directly over the South Pole, heating it by more than 1.83C (approximately 3.3F) since 1989.
The authors of the research said the natural warming trend was likely driven by human-made greenhouse gas emissions and may be masking the warming effect of carbon pollution at the South Pole.
“While temperatures were known to be warming in West Antarctica and the Antarctic Peninsula during the 20th century, the South Pole was cooling,” said Kyle Clem, a researcher at Victoria University of Wellington and lead author of the study.
“It was suspected that this part of Antarctica … could be immune / isolated from warming. We found that this is no longer the case,” he told AFP.
The data showed that the South Pole, the most remote place on Earth, was now warming up at a rate of around 0.6C (1.1F) per decade, compared to around 0.2C (0.4F) for the rest of the planet.
The authors of the study, published in the Climate change magazine, attributed the change to a phenomenon known as the Pacific Interdecadal Oscillation (IPO).
The IPO cycle lasts approximately 15-30 years, alternating between a “positive” state, in which the tropical Pacific is warmer and the northern Pacific colder than average, and a “negative” state where the anomaly is reversed Of temperature.
The OPI switched to a negative cycle at the turn of the century, driving higher convection and more pressure extremes at high latitudes, which led to a strong flow of warmer air over the South Pole.
Clem said the 1.83C (3.3F) warming level exceeded 99.99 percent of all moderate 30-year warming trends.
“While warming was within the natural variability of climate models, it is highly likely that human activity contributed,” he said.
© Agence France-Presse
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