26 Jun 2017

Record decline in Antarctic sea ice

1:24 pm on 26 June 2017

It has been the worst year on record for sea ice in Antarctica and a climate scientist suspects warmer ocean waters could be behind it.

Sea ice and pressure ridges in Antarctica.

Sea ice and pressure ridges in Antarctica. Photo: BY 2.0 NASA Goddard Space Flight Center

In a just released paper, the British Antarctic Survey says a series of unprecedented storms over the Southern Ocean likely caused the most dramatic decline in Antarctic sea ice to date.

Antarctic sea ice declined sharply in late 2016 and by late March this year the ice had reached its lowest level since records began nearly 40 years ago.

British Antarctic Survey found that a series of storms at the end of last year brought warm air and strong winds from the north that melted 75,000sqkm of ice per day.

"That's like losing a South Carolina-sized chunk of ice every 24 hours."

Victoria University climate scientist, James Renwick, said the ocean around the Antarctic had been warming down at depth, and the expectation was that that warmer water would start to surface, resulting in below-average sea ice levels.

"The fact that the sea ice extent has stayed near record-low levels almost every day since last October is pretty remarkable.

"We haven't seen a year like this and I suspect, we don't have the measurements yet - but I suspect that warmer ocean waters a little bit below the surface might be helping here."

James Renwick said the scientists would have to wait and see what caused the sea ice loss in the last year and whether it would actually recover.

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