Current ice-sheet models present uncertainty regarding the future of Antarctica's glaciers after 2100, the researchers explained in their publication in 'Earth's Future'. By merging data from 16 distinct ice-sheet models, the team discovered a general consensus that ice loss in Antarctica will continue to increase gradually through the 21st century, even if emissions remain at current levels.
However, beyond 2100, the models suggest a sharp change. The researchers found that, under current emission scenarios, ice in many of Antarctica's western basins will start to retreat rapidly. By the year 2200, this could contribute as much as 5.5 feet to global sea levels. In some simulations, the Antarctic ice sheet could face near-total collapse by 2300.
"When policymakers and stakeholders discuss sea-level rise, the focus is largely on what may occur by 2100. Very few studies look beyond that point," noted Helene Seroussi, the study's lead author and associate professor at Dartmouth's Thayer School of Engineering.
"Our study offers the long-term projections that have been missing," she continued. "These findings show that after 2100, the long-term effects on regions most vulnerable to sea-level rise become significantly more pronounced."
The study also explored the future of Antarctica's ice sheet under both high- and low-emission scenarios through the year 2300, explained Mathieu Morlighem, a professor of earth sciences at Dartmouth and a coauthor of the research. Dartmouth alumnus Jake Twarog, who contributed to the study as an undergraduate, was also listed as a coauthor.
"While current emissions have a limited effect on model projections for this century, the impact of high- versus low-emission scenarios on sea-level rise diverges sharply after 2100," Morlighem added. "These results emphasize the critical importance of reducing carbon emissions now to safeguard future generations."
The timing of glacier retreats varied depending on the ice-flow model used, Seroussi explained. However, once rapid ice loss began, all models consistently showed large-scale retreats happening at a similar pace.
"All the models agree that once these major changes are triggered, there is no stopping or slowing them. Several West Antarctic basins could see total collapse before 2200," said Seroussi. "The precise timing of these collapses remains uncertain and will depend on future greenhouse gas emissions, making it essential to act swiftly to cut emissions before major Antarctic basins are lost."
The findings could pave the way for further collaborative models that scientists can use to address discrepancies in projections for regions with high modeling uncertainty, including the Greenland ice sheet. Seroussi noted that this approach would help direct research and computational resources to the most likely scenarios predicted by multiple models.
"We're gaining insights from the scientific community on what to expect," Seroussi commented. "This collaborative effort provides a clearer understanding of uncertainties, highlighting where models agree and disagree, and helping us focus future research where it's most needed."
Research Report:Evolution of the Antarctic Ice Sheet Over the Next Three Centuries From an ISMIP6 Model Ensemble
Related Links
Dartmouth College
Beyond the Ice Age
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