Antarctica: World's 'biggest lumps of ice' increasingly unstable if climate change goes on


The East Antarctic Ice Sheet is the world’s biggest block of ice, containing enough water to raise the global sea level by 193ft (58m). The ice sheet contains some 6.5 million cubic miles (27 million cubic km) of ice and accounts for most of the frozen continent. And although the ice sheet is more stable than its neighbours, such as the Ross Ice Shelf and Thwaites Ice Shelf, its future is looking increasingly uncertain.

Under a warming climate, the planet’s polar and glacial regions are facing undue stress and melting.

The melting threatens to substantially raise sea levels, increase rates of coastal flooding and lead to more extreme weather by impacting ocean circulation.

An international team of scientists led by researchers in Germany has now examined how will impact the world’s biggest ice sheet.

The study was led by scientists at the Institute of Earth Sciences at Heidelberg University and involved researchers from the University of Southampton in the UK.

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In a study published today (November 23) in Proceedings of the National Academy of Sciences of the United States of America, the researchers presented worrying data about the future stability of the Antarctic ice shelf.

The data suggests in the near future, if continues, the East Antarctic Ice Sheet could be less stable than previously thought.

Dr Kim Jacob from Heidelberg University said: “The future melting of polar ice sheets and the associated rise in global sea level as a consequence of climate change will have a substantial impact on low-elevation coastal areas.”

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The scientists carried out a geochemical analysis of deep-sea sediments from the Atlantic Ocean.

Typically, the growth and loss of polar ice sheets is affected by solar radiation and atmospheric CO2.

But the new study has found a third factor in the Antarctic ice sheet’s stability: the fall of global sea levels caused by the formation of large ice sheets in the Northern Hemisphere.

As the sea levels dropped, the Antarctic ice sheet was less exposed to warmer ocean waters that could melt parts of the ice sheet.

Professor Paul Wilson of the University of Southampton’s Ocean and Earth Science department said: “Our data provide an unusually high-resolution image of changes in ocean temperature, ice volume and sea level for an interval when atmospheric CO2 levels were last as high as they are today.

“We can see that before 2.5 million years ago in our records peak sea levels were so high that some of even the biggest lumps of ice on Earth, the East Antarctic Ice Sheet, melted.”

The scientists believe their study highlights the East Antarctic Ice Sheet’s vulnerability to climate change.

And if global warming is allowed to continue, there is a heightened risk the ice sheet will be further destabilised by rising sea levels.

Professor Wilson added, “We suspect that the melting occurred in areas where the Antarctic Ice Sheet was in contact with a rising, warming, ocean driven by retreat of other ice sheets in the northern hemisphere; a sort of vicious circle”.





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