What has stopped Antarctica from warming
The secret to why Antarctica is not warming as much as the other continents, and why Australia faces more droughts lies in strengthening of ocean winds due to climate change, a study said.
Rising levels of carbon dioxide in the atmosphere are strengthening the stormy Southern Ocean winds which deliver rain to southern Australia, but pushing them further south towards Antarctica, the findings showed.
"With greenhouse warming, Antarctica is actually stealing more of Australia's rainfall. It is not good news - as greenhouse gases continue to rise we will get fewer storms chased up into Australia," said Nerilie Abram from the Research School of Earth Sciences, Australian National University.
As the westerly winds are getting tighter they are actually trapping more of the cold air over Antarctica, Abram added.
"This is why Antarctica has bucked the trend. Every other continent is warming, and the Arctic is warming fastest of anywhere on earth," she noted.
Until this study, Antarctic climate observations were available only from the middle of last century.
By analysing ice cores from Antarctica, along with data from tree rings and lakes in South America, Abram and her colleagues were able to extend the history of the westerly winds back over the last millennium.
"The Southern Ocean winds are now stronger than at any other time in the past 1,000 years," Abram said.
The strengthening of these winds has been particularly prominent over the past 70 years and the researchers linked this to rising greenhouse gas levels.
While most of Antarctica is remaining cold, rapid increases in summer ice melt, glacier retreat and ice shelf collapses are being observed in Antarctic Peninsula, where the stronger winds passing through Drake Passage are making the climate warm exceptionally quickly.
The study appeared in the journal Nature Climate Change.
(Posted on 13-05-2014)
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