Small changes in the temperature of the Southern Ocean can cause ripple effects across the Antarctic ice sheet that could raise sea levels, according to new research from Victoria University.
Research proved that sea temperatures don’t just affect the margins of the large Antarctic ice sheet, but throughout its interior.
The close connection exists because of ‘ice streams’ – narrow corridors of fast moving ice, which connect the interior to the Southern Ocean.
The study was led by Dr Nicholas Golledge, from Victoria University’s Antarctic Research Centre, and Dr Chris Fogwill from the University of New South Wales.
Using a new continental-scale ice sheet model, Dr Golledge and his colleagues have been able to demonstrate that large sectors of the ice sheet are highly sensitive to even small changes in the Southern Ocean.
“We found that the ice streams, which are like arteries of flowing ice, are capable of triggering rapid, significant changes right through to the interior of the ice sheet,” said Dr Golledge.
The researchers ran model simulations and compared the results with geological reconstructions of the ice sheet as it would have been 20,000 years ago, during the last glacial maximum.
By doing so they were able to analyse the effects of ocean warming and sea-level rise across the entire Antarctic ice sheet.
They indicated that while glacier accelerations triggered by changes in the Southern Ocean are relatively localised, the extent of the ice-sheet thinning that also occurs is far more widespread.
Dr Golledge said the research attempt to address a key uncertainty in predicting future sea-level rise, and these results imply a rapid response from the ice sheet as the ocean around Antarctica warms
The ocean has taken up eighty percent of the heat from global warming and much of this occurring in the Southern Ocean around Antarctica.
“We can see right now these warm ocean currents are already melting the marine margin of the ice sheet in the Amundsen Sea, said Dr Golledge.
The research out of Victoria University is important because ice sheets lock up vast quantities of water, which could potentially raise global sea levels by metres.
So, researchers now have to ask ‘how quickly?’