SYDNEY (AFP) — The longest continuous record of temperature changes in the Southern Ocean has found that Antarctic waters are warming and sea levels are rising, an Australian scientist said Monday.
The data from a joint Australian, French and US programme has been collected over 15 years by the French supply ship L'Astrolabe during its regular voyages to the Antarctic base Dumont D'Urville.
Steve Rintoul, who leads the Australian side of the programme, said the data had given scientists a foundation for studying the remote and inhospitable Antarctic waters and how changes there could impact on the global climate.
"The main result probably is very simple to state, I guess, which is that the ocean is warming," he said.
"Temperatures on the upper ocean have warmed by several tenths of a degree. It depends a little bit on where you are in the Southern Ocean but a ballpark number might be about three-tenths or so of a degree."
Rintoul said while oceans around the globe were heating up, the latest measurements from the programme showed that the warming extended particularly deeply in the Southern Ocean.
"The temperature change is smaller in the Southern Ocean than some other locations but the amount of heat stored by the ocean is larger," he said.
"And that's important because it means that more heat is being stored in the Southern Ocean than elsewhere and that means that the sea level has a tendency to rise more because warmer water expands and so sea level rises," he told AFP.
Over the last decade, sea levels have risen by about three centimetres (1.18 inches) in the area where this programme is operating, he said.
Rintoul, who works at the marine research unit of Australia's Commonwealth Scientific and Industrial Research Organisation, said the programme allowed scientists to assess for the first time how the flow of the world's largest ocean current, the Antarctic Circumpolar Current, changed with time.
Scientists have also examined how wind changes over the Southern Ocean may have resulted in Antarctic ice shelves melting and collapsing and linked these changes to drought conditions in southern Australia, he said.
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