The point of no return for Antarctic's ice

Calving front of Fleming Glacier, an outlet glacier which fed the former Wordie Ice Shelf (Supplied / Matthias Braun, University of Erlangen-Nuremberg)
Calving front of Fleming Glacier, an outlet glacier which fed the former Wordie Ice Shelf (Supplied / Matthias Braun, University of Erlangen-Nuremberg)

As the world continues to warm, a European team of scientists have mapped out which areas of Antarctica we really can't afford to lose without causing cataclysmic damage.

Dire warnings have previously been issued about the state of Antarctica's shrinking ice shelves and the new research, published in this week's Nature Climate Change journal, uncovers how much impact the loss of different shelves would have.

Antarctica is made up of a mix of floating and grounded ice shelves, and the floating sheets help support the grounded. That means there's only a certain portion of floating ice shelves that can be lost before the grounded portion slips into the ocean, according to the study's authors.

While some regions, such as the Shackleton ice shelf in the Mawson Sea, have a large amount of ice shelves which provide little or no support to the grounded ice shelves and can be lost without much harm, they're the exception rather than the rule.

The paper calculates only 13.4 percent of the floating areas around Antarctica are "passive shelf ice" (PSI), which can be lost with little to no impact.

And for the Bellingshausen and Amundsen seas, their PSI is well below the Antarctic average at 5.3 and 7.9 percent respectively, with "substantial" melt rates in the areas.

The point of no return for Antarctic's ice

Highly crevassed ice front of Ferrigno Ice Stream in the Bellingshausen Sea (Supplied / Matthias Braun, University of Erlangen-Nuremberg)

But the numbers can get still grimmer -- Cosgrove and Dotson ice shelves, both located in the Amundsen Sea, have the smallest amount of ice which can be lost, at a measly 2.7 and 1.5 percent of their shelves respectively.

Because for the past 20 years the ice shelves have been thinning at an alarmingly high rate, the study's authors say there needs to be in-depth monitoring of the ice shelves with little PSI, keeping track of the changes in the thickness of the ice and the formation of fractures within it.

If the melt exceeds the "safety band" outlined by the research, the icy continent's future could be at risk.

Last year, a study by Kiwi and Australian scientists modelled what effect different levels of carbon emissions would have on the Antarctic ice sheet.

It found unless world emissions were significantly reduced beyond 2020, there would be a large-scale loss of Antarctic ice which could result in sea level rising up to 10m by the year 2100.

They suggested atmosphere warming be kept under 2degC in order to prevent that and late last year, 190 countries came together to formally agree to the warming cap by 2100, with a target of 1.5degC.

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