Current Climate Warming Enough to Set West Antarctica on Path to Irreversible Collapse

The Cryosphere, 7 September 2023

Two groundbreaking studies reveal that remaining at today’s 1.2°C could trigger the slow but certain loss of parts of West Antarctica over coming centuries, even with no additional warming beyond current temperatures. Once initiated, this ice loss and sea level rise cannot be reversed. Experts from major European research institutions joined together to create the first systematic inspection of the ice sheet’s current stability. Their conclusion: while runaway retreat has not yet started, staying even at present-day temperatures would, over time, cause 2.7 to 3.5 meters of global sea level rise from this section of Antarctica alone. This is because many regions of the West Antarctic ice sheet are precariously balanced on sloped bedrock that could produce unstoppable ice loss if this retreat crosses a threshold, triggering a domino-effect of ice breaking away and slipping into the ocean. Authors warn that given already-warming waters around West Antarctica, this threshold might be reached within 300 years even if temperatures remain stable at today’s 1.2°C. Anthropogenic fossil fuel emissions are on track however to hit 2.7°C by 2100 under current trajectories, which several studies show could cause far more rapid irreversible ice loss. A full collapse of West Antarctica would take centuries to millennia, but can be avoided with urgent climate action. Only rapid emissions reductions provide the best possible chance to avoid crossing this dangerous threshold of irreversible, multi-meter sea-level rise from West Antarctica.

Two associated papers on “The stability of present-day Antarctic grounding lines”:
Part 1 | https://tc.copernicus.org/articles/17/3739/2023/
Part 2 | https://tc.copernicus.org/articles/17/3761/2023/

By Amy Imdieke, Global Outreach Director, and Pam Pearson, Director of ICCI.
Published Sep. 11, 2023      Updated Sep. 11, 2023 5:24 pm

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