Antarctic Sea Ice Extent Down 20% Since 1950s

Antarctic sea ice declines 20pc
14nov03

"ANTARCTIC sea ice has decreased by about 20 per cent since the 1950s, groundbreaking Australian research has found. A team led by Australian Antarctic Division senior ice core chemist Mark Curran has harnessed new technology to piece together changes to sea ice dating back to 1840.

Hailed as the first long-term evidence of sustained decline, the study results will be published today in the latest edition of Science. Dr Curran said glaciologists had developed and calibrated a new tool to measure chemical signals in ice core samples collected from the Law Dome, near Australia's Casey station.

'What we have done is used a chemical in the ice core called Methane Sulfonic Acid (MSA),' he said. MSA is produced by tiny single-cell ocean plants called phytoplankton. 'The amount of MSA in the ice core is related to the northerly extent of the Antarctic sea ice,' Dr Curran said. 'Therefore, in years where you have more sea ice, you get more algae, and they produce more MSA.'

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'What we show is the first evidence of a sustained sea ice decline since the 1950s.' He said the data showed a 20 per cent loss in sea ice since the 1950s over the region closest to the ice core."

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The article indicates that the record was extended back to 1840. That's a full 160 years! Wonder what the first 110 years indicated?