A study led by Dartmouth has compiled 16 models to refine projections of ice loss up to the year 2300.

A study led by Dartmouth, involving over 50 climate scientists from around the globe, offers the first clear projection of how carbon emissions could contribute to the loss of Antarctica’s ice sheet over the next 300 years.

The future of Antarctica’s glaciers after 2100 becomes uncertain when looking at existing ice-sheet models individually, the researchers report in the journal Earth’s Future. 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.

Uncertainty After 2100 and Potential Rapid Ice Loss

But that consistency falls off a cliff after 2100, the researchers found. The models predict that under current emissions, ice in most of Antarctica’s 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’s numerical experiments projected a near-total collapse of the Antarctic ice sheet by 2300.

“When 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,” says Hélène Seroussi, the study’s first author and an associate professor in Dartmouth’s Thayer School of Engineering.

“Our study provides the longer-term projections that have been lacking,” she says. “The results show that beyond 2100, the long-term impact for the regions most susceptible to sea-level rise become amplified.”

High- vs. Low-Emission Scenarios

The researchers modeled how Antarctica’s ice sheet would fare under both high- and low-emission scenarios through 2300, says Mathieu Morlighem, a Dartmouth professor of earth sciences and a co-author on the study. Dartmouth Engineering alumnus Jake Twarog ’24 also is a co-author of the study and contributed as an undergraduate.

“While 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,” Morlighem says. “These results confirm that it is critical to cut carbon emissions now to protect future generations.”

The timing of when Antarctica’s 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.

“All 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,” Seroussi says. “The 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 in Antarctica are lost.”

Future Collaboration and Research Directions

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.

“We’re learning from the community of scientists what is going to happen,” Seroussi says. “This 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.”

Reference: “Evolution of the Antarctic Ice Sheet Over the Next Three Centuries From an ISMIP6 Model Ensemble” by Hélène Seroussi, Tyler Pelle, William H. Lipscomb, Ayako Abe-Ouchi, Torsten Albrecht, Jorge Alvarez-Solas, Xylar Asay-Davis, Jean-Baptiste Barre, Constantijn J. Berends, Jorge Bernales, Javier Blasco, Justine Caillet, David M. Chandler, Violaine Coulon, Richard Cullather, Christophe Dumas, Benjamin K. Galton-Fenzi, Julius Garbe, Fabien Gillet-Chaulet, Rupert Gladstone, Heiko Goelzer, Nicholas Golledge, Ralf Greve, G. Hilmar Gudmundsson, Holly Kyeore Han, Trevor R. Hillebrand, Matthew J. Hoffman, Philippe Huybrechts, Nicolas C. Jourdain, Ann Kristin Klose, Petra M. Langebroek, Gunter R. Leguy, Daniel P. Lowry, Pierre Mathiot, Marisa Montoya, Mathieu Morlighem, Sophie Nowicki, Frank Pattyn, Antony J. Payne, Aurélien Quiquet, Ronja Reese, Alexander Robinson, Leopekka Saraste, Erika G. Simon, Sainan Sun, Jake P. Twarog, Luke D. Trusel, Benoit Urruty, Jonas Van Breedam, Roderik S. W. van de Wal, Yu Wang, Chen Zhao and Thomas Zwinger, 04 September 2024, Earth’s Future.
DOI: 10.1029/2024EF004561