The runaway collapse of the West Antarctic ice sheet – which would trigger catastrophic sea level rise – is not “inevitable,” scientists said Monday after research tracking the region’s recent responses to climate change.
As global temperatures rise, there is growing concern that warming could trigger so-called tipping points, triggering irreversible melting of the world’s massive ice sheets and ultimately lifting the oceans to the point of drastically redrawing the world map.
New research released Monday suggests a complex interplay of factors affecting the melting of the West Antarctic Ice Sheet, which is home to the massive and unstable Pine Island and Thwaites Glaciers – nicknamed the “Doomsday Glaciers” – which together form the could raise global sea levels by more than three meters (10 feet).
Using satellite imagery and ocean and climate records between 2003 and 2015, an international team of researchers found that the pace of ice loss in a vulnerable region of the coast slowed as the West Antarctic ice sheet continued to retreat.
Their study, published in the journal nature communicationconcluded that this slowdown was caused by changes in sea temperatures caused by offshore winds, with pronounced differences in impact by region.
The researchers said this raises questions about how rising temperatures will affect Antarctica, with ocean and atmospheric conditions playing a key role.
“This means that ice sheet collapse is not inevitable,” said co-author Professor Eric Steig of the University of Washington in Seattle.
“It depends on how the climate changes over the next few decades, which we could positively influence by reducing greenhouse gas emissions.”
The researchers observed that ice retreat in one region, in the Bellingshausen Sea, accelerated after 2003, while it slowed in the Amundsen Sea.
They concluded that this is due to changes in the strength and direction of offshore surface winds, which alter ocean currents and can disrupt the layer of cold water around Antarctica and sweep relatively warmer water toward ice.
Both the north and south polar regions have warmed by about three degrees Celsius compared to the end of the 19th century, almost three times the global average.
Scientists are increasingly concerned that Pine Island and Thwaites glaciers have reached a “tipping point” where irreversible melting could occur, regardless of reductions in greenhouse gas emissions.
Anders Levermann, a climate scientist at the Potsdam Institute for Climate Impact Research who was not involved in the latest study, welcomed the approach of bringing together multiple observations and records, even though the study period was “a blink of an eye into ice ages”.
“I think we still have to live and plan and do our sea level projections and coastal planning with the hypothesis that the West Antarctic Ice Sheet is destabilized and we’re going to get a 12 foot sea level rise from that area of the planet alone,” he said however, added that this would happen “over centuries to millennia”.
The United Nations’ scientific advisory body on climate change, the IPCC, has forecast that the oceans will rise by up to a meter by the end of the century and even more thereafter.
Hundreds of millions of people live just a few meters below sea level.
While reducing planet-warming emissions is believed to be the first and most important way to halt the melting of the West Antarctic Ice Sheet, scientists have also developed a number of high-tech proposals to save the giant ice shelf and defend against it.
Levermann has researched ideas including using snow cannons to pump trillions of tons of ice back onto the frozen region.
Other proposals included building pillars the size of an Eiffel Tower on the sea floor to support it from below, and a 100m high, 100km long berm to block warm water flowing below.
Interdecadal climate variability induces differential ice response along Pacific-facing West Antarctica, nature communication (2023). DOI: 10.1038/s41467-022-35471-3
© 2023 AFP
Citation: Runaway W. Antarctic Ice Sheet Collapse Not “Inevitable”: Study (2023, January 22) Retrieved January 22, 2023 from https://phys.org/news/2023-01-runaway-antarctic-ice-sheet- collapse.html
This document is protected by copyright. Except for fair trade for the purpose of private study or research, no part may be reproduced without written permission. The content is for informational purposes only.