West Antarctic Ice Sheet May Disappear by 2300

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A Dartmouth-led study compiles 16 models for the clearest projection of melting after 2100.

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H茅l猫ne Seroussi
Associate 天美影视 of Engineering H茅l猫ne Seroussi is the first author of the study in Earth鈥檚 Future. (Photo by Eli Burakian 鈥00)
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A Dartmouth-led study by more than 50 climate scientists worldwide provides the first clear projection of how carbon emissions may drive the loss of a large portion of Antarctica鈥檚 ice sheet over the next 300 years.

The future of Antarctica鈥檚 glaciers after 2100 becomes uncertain when looking at existing ice-sheet models individually, the researchers. They combined data from 16 ice-sheet models and found that, collectively, the projections agree that ice loss from Antarctica will increase, but gradually, through the 21st century, even under current carbon emissions.

But that consistency falls off a cliff after 2100, the researchers found. The models predict that under current emissions, ice in most of Antarctica鈥檚 western basins begins to retreat rapidly. By 2200, the melting glaciers could increase global sea levels by as much as 5.5 feet. Some of the team鈥檚 numerical experiments projected a near-total collapse of the West Antarctic ice sheet by 2300.

鈥淲hen you talk to policymakers and stakeholders about sea-level rise, they mostly focus on what will happen up to 2100. There are very few studies beyond that,鈥 says, the study鈥檚 first author and an associate professor at.

鈥淥ur study provides the longer-term projections that have been lacking,鈥 she says. 鈥淭he results show that beyond 2100, the long-term impact for the regions most susceptible to sea-level rise become amplified.鈥

The researchers modeled how Antarctica鈥檚 ice sheet would fare under both high- and low-emission scenarios through 2300, says, the Evans Family Distinguished 天美影视 of and a coauthor on the study. Dartmouth Engineering alumnus Jake Twarog 鈥24 also is a coauthor of the study and contributed as an undergraduate.

鈥淲hile current carbon emissions have only a modest impact on model projections for this century, the difference between how high- and low-emission scenarios contribute to sea-level rise grows sharply after 2100,鈥 Morlighem says. 鈥淭hese results confirm that it is critical to cut carbon emissions now to protect future generations.鈥

The timing of when Antarctica鈥檚 glaciers would start retreating varied with the ice-flow model the researchers used, Seroussi says. But the speed with which large retreats occurred once a rapid loss of ice began was consistent among the models.

鈥淎ll the models agree that once these large changes are initiated, nothing can stop them or slow them down. Several basins in West Antarctica could experience a complete collapse before 2200,鈥 Seroussi says. 鈥淭he exact timing of such collapses remains unknown and depends on future greenhouse gas emissions, so we need to respond quickly enough to reduce emissions before the major basins are lost.鈥

The study could lead to further collaborative models that scientists can use to understand and resolve disparities in projections for regions with significant modeling uncertainties, or for the Greenland ice sheet, Seroussi says. Research and computing resources can then be focused on investigating outcomes that those multiple models predict as most likely.

鈥淲e鈥檙e learning from the community of scientists what is going to happen,鈥 Seroussi says. 鈥淭his collaboration means we have a better, more robust assessment of the uncertainty, and we can see where our models agree and where they disagree so that we know where to focus our future research.鈥

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