A third of the Antarctic ice sheet is threatened with collapse as the planet warms

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More than a third of the surface of the Antarctic ice sheet could be at risk of collapsing into the sea if global temperatures reach 4 ° C above pre-industrial levels, new research has shown.

The University of Reading has conducted the most detailed study that has ever predicted how large floating ice platforms surrounding Antarctica will become vulnerable to dramatic collapse events caused by melting and runoff, as climate change forces temperatures to rise.

It found that 34% of the surface of all Antarctic ice shelves – about half a million square kilometers – including 67% of the surface of ice sheets in the Antarctic Peninsula, would be at risk of destabilization under 4 ° C heating. Limiting temperature rise to 2 ° C rather than at 4 ° C, would halve the area at risk and potentially avoid significant sea level rise.

Researchers have also identified Larsen C – the largest remaining ice sheet on the peninsula, which split to create the huge A68 iceberg in 2017 – as one of four ice shelves that would be particularly vulnerable in warmer climates.

Dr Ella Gilbert, a researcher in the Department of Meteorology at the University of Reading, said: “Ice shelves are important buffers that prevent glaciers on land from flowing freely into the ocean and contributing to sea level rise. When they collapse, it’s like a giant cork being removed from bottles, allowing unimaginable amounts of water from glaciers to pour into the sea.

“We know that when melted ice accumulates on the surface of ice shelves, it can lead to their cracking and spectacular collapse. Previous research has given us a broader picture in terms of predicting the fall of the Antarctic ice field, but our new study uses the latest modeling techniques to fill finer details and provided more accurate projections.

“The findings highlight the importance of limiting global temperature increases as set out in the Paris Agreement if we are to avoid the worst consequences of climate change, including rising sea levels.”

A new study published in Letters on geophysical research journal, used state-of-the-art high-resolution regional climate modeling for more detailed prediction than before the impact of increased melting and runoff on ice shelf stability.

The vulnerability of the ice field due to this breaking process was predicted under global warming scenarios of 1.5 ° C, 2 ° C and 4 ° C, all of which are possible in this century.

Ice shelves are permanent floating ice platforms attached to areas of the shoreline and formed where glaciers flowing from the mainland meet the sea.

Every summer the ice on the surface of the ice sheet melts and flows into small air gaps in the snow layer below, where it freezes. However, in years when there is a lot of melting but little snow, water collects on the surface or pours into the cracks, deepening them and expanding until the ice sheet eventually cracks and collapses into the sea. If water collects on the surface of the ice shelf, this suggests that it could be prone to collapse in this way.

This happened with the Larsen B ice shell in 2002, which burst after several years of warm summer temperatures. Its collapse accelerated the glaciers behind the ice field, losing billions of tons of ice in the sea.

Researchers have identified the ice shelves of Larsen C, Shackleton, Pine Island and Wilkins as the most endangered under 4 ° C heating, due to their geography and the significant water runoff predicted in these areas.

Dr. Gilbert said: “If temperatures continue to rise at current speeds, we could lose more Antarctic ice shelves in the coming decades.

“Limiting warming isn’t going to be good for Antarctica alone – preserving ice shelves means less global sea level rise, and that’s good for all of us.”

A new study provides data on sea level rise after the fall of Antarctic ice shelves

More information:
Letters on geophysical research (2021). DOI: 10.1029 / 2020GL091733

Provided by the University of Reading

Citation: A third of the Antarctic ice sheet is in danger of collapsing as the planet warms (2021, April 8) taken on April 8, 2021 from https://phys.org/news/2021-04-antarctic-ice-shelf-area-collapse .html

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