Extreme Temperature Diary- Saturday November 14th, 2024/Main Topic: Good News Concerning the Thwaites glacier?

https://www.newsweek.com/scientists-wrong-about-doomsday-glacier-thwaites-antarctica-1999961

Scientists May Have Been Wrong About ‘Doomsday Glacier’

By Tom Howarth Science Reporter (Nature)

A recent study has challenged some of the most alarming predictions about Thwaites Glacier in Antarctica, dubbed the “Doomsday Glacier,” owing to the seismic impacts it could have on the world’s oceans.

The research suggested that a catastrophic collapse of the glacier, which could lead to rapid and dramatic sea-level rise, is less likely to occur this century than previously thought.

The Thwaites Glacier in West Antarctica has been a major focus for climate scientists due to its unstable nature and significant contribution to global sea-level rise.

Currently, it accounts for about 4 percent of the annual increase in sea levels and holds enough ice to raise them by over two feet if it fully melts, according to the International Thwaites Glacier Collaboration (ITGC).

But the findings offer a glimmer of hope amid growing concerns about the impacts of climate change on the Antarctic.

Published in Science Advances and led by researchers at Dartmouth College, the study reevaluated a process known as marine ice cliff instability (MICI).

MICI predicts that when ice shelves collapse, they expose towering ice cliffs that could crumble under their own weight, triggering a chain reaction of rapid glacier retreat.

While MICI has featured prominently in worst-case climate models, it has never been observed in real-world conditions and was previously simulated using older, low-resolution models.

Using updated computer simulations, the Dartmouth team found that MICI is unlikely to occur this century at Thwaites. Even if the glacier’s entire ice shelf were to collapse today, the resulting ice cliffs would likely not be tall enough to crumble and trigger the catastrophic chain reaction previously feared.

“We’re not saying the Antarctic is safe,” Professor Mathieu Morlighem, the study’s lead author from Dartmouth College, said in a statement.

Antarctica’s Thwaites Glacier. The glacier has gained notoriety for its vulnerability ot destabilization, and even collapse. NASA

But the findings offer a glimmer of hope amid growing concerns about the impacts of climate change on the Antarctic.

Published in Science Advances and led by researchers at Dartmouth College, the study reevaluated a process known as marine ice cliff instability (MICI).

MICI predicts that when ice shelves collapse, they expose towering ice cliffs that could crumble under their own weight, triggering a chain reaction of rapid glacier retreat.

While MICI has featured prominently in worst-case climate models, it has never been observed in real-world conditions and was previously simulated using older, low-resolution models.

Using updated computer simulations, the Dartmouth team found that MICI is unlikely to occur this century at Thwaites. Even if the glacier’s entire ice shelf were to collapse today, the resulting ice cliffs would likely not be tall enough to crumble and trigger the catastrophic chain reaction previously feared.

“We’re not saying the Antarctic is safe,” Professor Mathieu Morlighem, the study’s lead author from Dartmouth College, said in a statement.

These findings challenge high-risk scenarios in reports from bodies like the United Nations Intergovernmental Panel on Climate Change (IPCC). While the IPCC had included MICI-driven collapse in its projections for extreme sea-level rise, the new research suggests that Thwaites’ retreat will likely remain gradual through the 21st century.

Even without MICI, the melting of Thwaites and neighboring glaciers remains a significant concern.

The bedrock beneath Thwaites slopes downward as it moves inland, making it difficult to slow its retreat once it starts losing more ice than it gains from snowfall.

With climate warming accelerating this process, the glacier’s instability could still have long-term consequences.

Since 2018, the ITGC, a collaboration between the U.S. and the U.K., has been closely monitoring Thwaites, a glacier roughly the size of Florida.

Just months ago, scientists were warning that the glacier could be heading for an imminent collapse.

“Thwaites is almost like the jugular of Antarctica,” Kiya Riverman, a glaciologist at the University of Portland who is involved in the ITGC, previously told Newsweek. “It’s a point at which damage is incredibly impactful to us.”

She added, “We’ve already crossed a tipping point with Thwaites.”

While the risk of a dramatic collapse this century may be reduced, the long-term impacts of Antarctic ice loss remain a pressing concern.

Currently, sea levels are rising by 0.13 inches per year, according to NASA. Much of this rise is driven by melting ice in the polar regions.

“The sooner we prioritize and try to understand these changes, the more we’re going to set up future generations for success in mitigating the effects,” Riverman said.

Do you have a tip on a science story that Newsweek should be covering? Do you have a question about sea level rise? Let us know via science@newsweek.com.

Reference

Morlighem, M., Goldberg, D., Barnes, J. M., Bassis, J. N., Benn, D. I., Crawford, A. J., Gudmundsson, G. H., & Seroussi, H. (2024). The West Antarctic Ice Sheet may not be vulnerable to marine ice cliff instability during the 21st century. Science Advances10(34), eado7794. https://doi.org/10.1126/sciadv.ado7794

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