A study published this week drew on computer models to investigate what would happen if "pulses" of meltwater were released by the Antarctic ice sheet into the Southern Ocean. Photo / Nick Golledge
A study published this week drew on computer models to investigate what would happen if "pulses" of meltwater were released by the Antarctic ice sheet into the Southern Ocean. Photo / Nick Golledge
Changes taking place in Antarctica are significant enough to influence those on the other side of the planet, new research co-authored by a Kiwi scientist has found.
A study published this week in leading scientific journal Nature drew on computer models to investigate what would happen if "pulses" of meltwater were released by the Antarctic ice sheet into the Southern Ocean.
The models showed that although the influx triggered cooling of the sea surface around Antarctica, temperatures deeper in the ocean began to rise, said study author Dr Nick Golledge, of Victoria University's Antarctic Research Centre.
"This response is well-known, but what is less-known is that the input of fresh water also leads to changes far away in the Northern Hemisphere, because it disrupts part of the global ocean circulation.
"This means that meltwater from the Antarctic ice sheet won't just raise global sea level, but might also amplify climate changes around the world."
Some parts of the north Atlantic could end up with warmer air temperatures as a consequence of part of Antarctica melting, he said.
The research team, led by Dr Pepijn Bakker from Germany's Centre for Marine Environmental Sciences, used its models to simulate how Antarctica and the global climate may have changed during the last 8000 years.
"I used a computer model to simulate how the Antarctic ice sheet changed as we came out of the last ice age and into the present, warm period," Golledge said.
Scientists estimate that if all of the continent melted, it would contribute around 60 metres of sea level rise - with the bulk of it coming from the vast East Antarctic Ice Sheet. Photo / Nick Golledge
"We then took the outputs and fed them into the climate model to see what the effect on global temperatures would be.
"We ran lots of experiments and compared the results with data from geological records to get a better idea of the timescales involved in these processes."
The study also found that high-frequency changes in ocean temperatures tend to be absorbed by the Antarctic ice sheet, which then responded more slowly.
"Whilst this might be seen as a good thing, it also implies that once the ice sheet starts responding, by melting, it may be too late to prevent the consequences."
Interpreting these results, Dr Bakker and his team conclude that the Antarctic ice sheet plays a major role in regional and global climate variability - a discovery that may also help explain why sea ice in the Southern Hemisphere has been increasing despite the warming of the rest of the Earth.
Over recent years, scientists have observed glaciers around Antarctica shed trillions of tonnes of water.
In recent months, Nasa observers have been closely watching a 100-metre wide rift in the Larsen C Ice Shelf in the Antarctic Peninsula, with more monitoring planned to see whether it might follow the behaviour of the Larsen B Ice Shelf, which experienced weeks of rapid disintegration in 2002.
Scientists estimate that if all of the continent melted, it would contribute around 60 metres of sea level rise - with the bulk of it coming from the vast East Antarctic Ice Sheet.
