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One-third of Antarctica’s ice shelf risks collapsing as our planet warms



In a forecasting study, scientists found that 34% of the area of ​​all Antarctic ice shelves, measuring about half a million square kilometers, could be destabilized if global temperatures rose by 4 degrees. About 67% of the Antarctic ice shelf would be at risk of destabilization in this scenario, the researchers said.

Ice shelves are permanent floating ice platforms attached to areas of the coastline formed where glaciers flowing offshore meet the sea. They can help curb rising sea levels by acting as a dam, slowing the flow of melting ice and water into the oceans.

Every summer, the ice on the surface of the ice shelves melts and flows into smaller gaps in the snow below, where it usually freezes. But when there is a lot of melting and little snowfall, this water instead accumulates on the surface of the ice or flows into cracks. This deepens and widens the cracks, leading to breakage and collapse in the sea.

“Ice shelves are important buffers that prevent glaciers on land from flowing freely into the ocean and contributing to rising sea levels. When they collapse, it̵

7;s like a giant cork removed from a bottle, allowing unimaginable amounts of water from glaciers to flow. pour into the sea, “said study lead author Ella Gilbert, a climate scientist at the University of Reading’s Department of Meteorology.

Gilbert told CNN that low-lying coastal areas, especially small island states such as Vanuatu and Tuvalu, in the South Pacific, are most at risk of global sea level rise.

“However, coastal areas around the world would be vulnerable and countries with fewer resources available to mitigate and adapt to sea level rise will see worse consequences,” she said.

In a new study that uses high-resolution regional climate modeling to predict the impact of increased melting and runoff on ice shelf stability, researchers say limiting temperature rise to 2 degrees Celsius instead of 4 degrees Celsius. Celsius would halve the risk area and potentially avoid a significant rise in sea level.

The Intergovernmental Panel on Climate Change concluded in a significant report that we only have until 2030 to drastically reduce our dependence on fossil fuels and prevent reaching the crucial threshold of 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels. levels.

This image shows a large iceberg that has separated from the Pine Island Glacier.

Net global carbon emissions will have to fall by 45% from 2010 levels to 2030 and reach “net zero” around 2050 to keep warming around 1.5 degrees Celsius.

“The findings underscore the importance of limiting global warming, as set out in the Paris Agreement, in order to avoid the worst effects of climate change, including rising sea levels,” Gilbert added.

In the Paris Agreement, 197 countries agreed to keep global temperatures “well below” 2 degrees Celsius above pre-industrial levels and to continue their efforts to limit it to 1.5 degrees Celsius.

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But we are on our way to a world that is 3.2 degrees Celsius warmer by the end of the century.

Gilbert told CNN that higher temperatures mean melting is happening more often and more intensely.

Researchers have identified four ice shelves that would be threatened by warmer climates: the Larsen C, Shackleton, Pine Island and Wilkins ice shelves, which are vulnerable due to their geography and projected outflow in these areas.

Larsen C is the largest remaining ice shelf on the Antarctic Peninsula, and the Pine Island Glacier has received a lot of attention in recent years because it is melting rapidly in response to climate change, Gilbert said.

If these ice shelves collapse, which is not guaranteed, the glaciers they hold at the moment will flow into the ocean, contributing to rising sea levels – potentially tens of centimeters, she explained.

The study was published Thursday in the journal Geophysical Research Letters.


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