Winds in the wild Southern Ocean are blowing at their strongest in a millennia as climate change shifts weather patterns, leaving Antarctica colder and Australia facing more droughts, a study showed yesterday.
Rising carbon dioxide levels were strengthening the winds, dubbed the "Roaring Forties" for their ferocity, and pushing them further south towards Antarctica, researchers from the Australian National University (ANU) said.
"The Southern Ocean winds are now stronger than at any other time in the past 1,000 years," said the study's lead researcher, Dr Nerilie Abram.
"The strengthening of these winds has been particularly prominent over the past 70 years, and by combining our observations with climate models we can clearly link this to rising greenhouse gas levels," she said.
The new research, published yesterday in the Nature Climate Change journal, explains why Antarctica is not warming as much as other continents.
The westerly winds, which do not touch the eastern parts of Antarctica but circle in the ocean around it, were trapping more cold air as they strengthened, with the world's southernmost continent "stealing more of Australia's rainfall", Abram said.
"This is why Antarctica has bucked the trend. Every other continent is warming, and the Arctic is warming fastest of anywhere on earth," she said.
The study's authors analysed ice cores from Antarctica, along with data from tree rings and lakes in South America. The research helped to explain why the westerlies were further cooling cold parts of the continent even as they were also driving "exceptionally quicker" warming in the Antarctic Peninsula, which juts out into their path, Abram said.
The strengthening westerlies drive up the temperature at the peninsula - the only part of Antarctica hit by the wind - through the warm, moist air they carry from the Southern Ocean.