A recent study conducted by over 50 climate scientists from around the globe presents a clear forecast indicating a swift retreat of Antarctica’s ice sheet post-2100 if current carbon emissions continue. It warns that global sea levels could rise by as much as 5.5 feet by the year 2200. This research integrated findings from 16 climate models, revealing that ice loss will gradually escalate throughout this century until the ice sheet reaches a state of high vulnerability, potentially nearing total collapse by 2300.
A study led by Dartmouth and involving more than 50 climate experts worldwide delivers the most definitive forecast regarding the impact of carbon emissions on the Antarctic ice sheet over the next three centuries.
The fate of Antarctica’s glaciers beyond 2100 becomes less certain when considering individual ice-sheet models, as highlighted by the researchers in the journal Earth’s Future. Their analysis of 16 ice-sheet models indicated that, as a whole, the forecasts agree that ice loss from Antarctica will progressively increase during the 21st century, even under present carbon emissions.
However, this consistency diminishes sharply after 2100, the researchers discovered. The models indicate that under the current emissions scenario, ice in the majority of Antarctica’s western basins will start to retreat rapidly. By 2200, the melting glaciers could lead to a global sea level rise of up to 5.5 feet. Some numerical experiments conducted by the team suggested a possible near-total collapse of the Antarctic ice sheet by 2300.
“When discussing sea-level rise with policymakers and stakeholders, the emphasis usually lies on the effects expected by 2100. Very few studies extend beyond that,” states Hélène Seroussi, the lead author of the study and an associate professor at Dartmouth’s Thayer School of Engineering.
“Our research fills the gap of long-term projections that have been missing,” she explains. “The findings reveal that after 2100, the long-term consequences for regions most prone to sea-level rise will be significantly heightened.”
The research team examined how the Antarctic ice sheet would respond under both high- and low-emission scenarios up to 2300, according to Mathieu Morlighem, a professor of earth sciences at Dartmouth and a coauthor of the study. Jake Twarog, a Dartmouth Engineering alumnus, also contributed to the study as an undergraduate coauthor.
“While the current carbon emissions have a relatively modest influence on model predictions for this century, the gap between high- and low-emission scenarios regarding sea-level rise widens markedly after 2100,” Morlighem remarks. “These results underscore the urgent need to reduce carbon emissions now to safeguard the future for coming generations.”
The onset of retreating glaciers in Antarctica varied based on the ice-flow model the researchers employed, according to Seroussi. Nonetheless, the rate at which significant withdrawals occurred once rapid ice loss commenced was consistently observed across models.
“All models concur that once these significant changes start, there is nothing that can halt or slow them down. Several basins in West Antarctica could face complete collapse before 2200,” Seroussi mentions. “The specific timing of these collapses remains uncertain and is influenced by future greenhouse gas emissions; hence, a swift response is required to cut emissions before major Antarctic basins are irretrievably lost.”
This study could foster additional collaborative models that scientists can utilize to understand and address differences in projections for areas with considerable modeling uncertainties, or with regard to the Greenland ice sheet, says Seroussi. Research and computational resources can then be concentrated on exploring outcomes deemed most likely by various models.
“We’re gaining insights from the scientific community about future developments,” Seroussi notes. “This teamwork enables us to have a better, more comprehensive evaluation of uncertainties, allowing us to identify where our models align and where they diverge, thus guiding our future research efforts.”
