Antarctica is spreading, say boffins

23 Apr 2009, 4:36 pm   -   Source: AAP
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New research suggests sea ice is spreading as the ozone hole causes fiercer storms in Antarctica. (Reuters)

New research suggests sea ice is spreading as the ozone hole causes fiercer storms in Antarctica. (Reuters)

An Australian ice expert has slammed British claims that diminishing Antarctic sea ice is affecting global temperatures, amid new findings that its surface area is increasing.

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The increases in Antarctic sea ice linked by British researchers to the hole in the ozone layer are not significant in terms of global temperature, an Australian expert says.

Australian Antarctic Division ice expert Dr Tony Worby says there's been a very significant decrease in sea ice and a net loss in shelf ice in Antarctica.

Sea ice is different from shelf ice on the continent, and its melting does not affect sea levels.

Fresh research from the British Antarctic Survey says Antarctica's sea ice surface area - not volume - is increasing, in parts.

The ozone hole is causing more storms and more fierce winds around the South Pole, and that's cooling down much of Antarctica, spreading the sea ice further on the ocean, it says.

Dr Worby says the British research is more about wind than temperature and global warming.

"They are talking about a one per cent per decade increase. That's not a very significant increase in Antarctic sea ice," Dr Worby said.

"It also doesn't tell you about the real variability in sea ice that we are seeing from one area to the next.

"Around the Antarctic peninsula we are seeing a very significant decrease in sea ice linked to more warm northerly winds in the area.

"That's where the Larsen B and the Wilkins ice shelves have collapsed."

Dr Worby said the same wind changes cooling parts of Antarctica, spreading sea ice, are warming these other large areas.

"So the British research is more a story about wind than it is about temperature," Dr Worby said.

Antarctica is losing between 0.2mm and 0.3mm of shelf ice each year, he said.

Sea ice is important for ocean circulation, which moves heat around the globe and affects climate systems, not sea level rises, he said.
 

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