A recent study led by researchers from Dartmouth College has brought new insights into the future of Antarctica’s Thwaites Glacier, also known as the Doomsday Glacier, which has long been considered a significant threat to global sea levels.
The study challenges one of the most alarming predictions made by the Intergovernmental Panel on Climate Change (IPCC) regarding the rapid collapse of Antarctic ice sheets.
While the research confirms that ice loss from Thwaites Glacier will continue to contribute to rising sea levels, the catastrophic scenarios predicted in the past may be less likely than previously thought.
Challenging the Extreme Predictions
The new research casts doubt on the more dramatic forecasts that have portrayed Thwaites Glacier as a ticking time bomb. According to earlier projections, particularly those put forth in the IPCC’s Special Report on the Ocean and Cryosphere, the potential for Marine Ice Cliff Instability (MICI)—a process that could cause the glacier’s ice cliffs to break apart rapidly and trigger a sudden collapse—was seen as a worst-case scenario.
This could have led to sea-level rise of up to 50 feet by the year 2100, inundating coastal cities across the globe. However, the Dartmouth-led study, which used high-resolution computer models to simulate the glacier’s behavior, suggests that this type of sudden collapse is "highly unlikely" within this century.
Mathieu Morlighem, the study’s lead author and a professor of earth sciences at Dartmouth, noted that the physics behind the MICI model were not properly represented in previous studies. “The physics underlying the extreme projection included in the IPCC report are inaccurate, and this has real-world effects,” Morlighem stated.
The study found that while Thwaites Glacier is still retreating and will continue to contribute to rising sea levels, the collapse will likely occur more gradually than previously thought. "We’re not seeing the kind of rapid disintegration of ice cliffs that some models have predicted," Morlighem added, offering a more measured perspective on the future of the glacier.
Implications for Climate Policy and Coastal Planning
This revised outlook has significant implications for policymakers and coastal planners who have been preparing for the worst-case scenario of rapid sea-level rise. The original MICI projections have been used to guide infrastructure investments in coastal defenses, such as seawalls, and relocation plans for communities at risk of flooding. According to Morlighem, “Policymakers and planners rely on these models, and they’re frequently looking at the high-end risk. They don’t want to design solutions and then the threat turns out to be even worse than they thought.”
However, the study's findings do not suggest that we are out of danger. The researchers emphasized that while the collapse of Thwaites Glacier is likely to be slower, it is still expected to contribute significantly to sea-level rise over the next few centuries. Morlighem clarified, "We’re not reporting that the Antarctic is safe and that sea-level rise isn’t going to continue—all of our projections show a rapid retreat of the ice sheet." This distinction is critical, as the glacier is still melting at an accelerated pace due to ocean warming, and its retreat is expected to continue contributing to global sea-level rise.
The Need for Continued Research
Despite the more tempered outlook, the study underscores the importance of continued research into the behavior of Antarctica’s ice sheets, particularly in the context of a warming climate. The ice shelves that help stabilize Thwaites Glacier are rapidly disintegrating due to the increasing temperature of ocean waters, which are eroding the glacier from below. The study’s findings highlight the complex dynamics at play, where even a slower collapse could have long-term consequences for coastal regions around the world.
Dan Goldberg, a glaciologist and co-author of the study, noted that more precise climate models are needed to fully understand the glacier’s future behavior. “While we did not observe the rapid collapse predicted by MICI in our simulations, Thwaites is still likely to retreat unstably in the coming centuries,” Goldberg explained. He added that continued observation and modeling will be crucial to accurately forecast how fast the ice will melt and to what extent it will contribute to rising sea levels.
Goldberg emphasized that, although the study provides a more optimistic view compared to previous predictions, it does not suggest that the threat is over. "We must remain vigilant and continue to monitor the situation closely because even a slower retreat can have serious implications for coastal cities around the world," he said.
What This Means for the Future
The study represents a significant development in the understanding of Antarctica’s role in climate change, but it also serves as a reminder that even moderate sea-level rise can have far-reaching consequences.
Coastal communities worldwide will still need to prepare for rising seas, and while the most extreme predictions of the glacier’s collapse may no longer be the most likely scenario, the gradual retreat of the Thwaites Glacier will continue to shape the future of global shorelines.
As scientists work to refine their models and improve the accuracy of their projections, the challenge remains to mitigate the effects of climate change and to protect vulnerable communities from its impacts. The retreat of the Thwaites Glacier, while slower than feared, still poses a long-term threat that will require concerted global efforts to address.