Antarctica’s Florida-sized Thwaites Glacier is melting more aggressively than previous projections indicated, according to new research published in October 2026. Scientists warn that seawater penetrating miles beneath the ice could double the glacier’s contribution to global sea-level rise by 2100, pushing water levels up by an additional 1.2 inches even without further climate warming.
The planet’s widest glacier, widely nicknamed the Doomsday Glacier
due to the catastrophe its collapse would trigger, is losing mass at an accelerated pace according to new research published in October 2026. Spanning an area of roughly 192,000 square kilometers—about the size of Senegal—Thwaites holds enough ice to raise global sea levels by more than two feet if it collapses entirely.
University of California and NASA Researchers Reveal Grounding Zone Realities
For decades, computer models treated the transition point where ice rests on bedrock and begins to float as a stable, fixed boundary known as the grounding line. A team of glaciologists from the University of California, Irvine, and NASA’s Jet Propulsion Laboratory developed a new ice sheet model to better understand the complex mechanics beneath the ice. Their findings show that this boundary is actually a grounding zone several miles wide where ocean water flushes in and out with the tides.
We have come to acknowledge a different arrangement beneath Earth’s major ocean-terminating glaciers.
Mattia Poinelli, project scientist at UCLA who was an Earth system science researcher at UC Irvine at the time of the study, via CNN
This dynamic, known as tidal pumping, lifts and lowers the thick ice sheet, allowing relatively warm ocean water to penetrate deep beneath the glacier and trigger vigorous melting. Researchers used synthetic aperture radar data from Finland’s ICEYE satellite constellation to detect these fluctuations along the main trunk of Thwaites Glacier.
Double the Projected Sea-Level Rise by 2100
When the research team adjusted their models to incorporate the physical reality of the grounding zone, the resulting projections doubled previous estimates. The calibrated model estimates that Thwaites Glacier will contribute up to 30 millimeters, or about 1.2 inches, of sea-level rise by 2100 under a constant climate forcing scenario.
That figure arrives before accounting for further ocean warming or other feedback processes that could accelerate deterioration. The study was published in the journal Nature Communications on 12 October 2026.
Thwaites Glacier in West Antarctica, the planet's widest and most unpredictable glacier, is melting "more aggressively" than previously projected, meaning its impacts on global sea level rise could be double current estimates. https://t.co/AtsKwZBd7x pic.twitter.com/xpt7YUsaT5
Our new model with more complete physics is able to match the record and then produces projections that are twice as large as before.
Eric Rignot, professor of Earth system science at UC Irvine and co-author of the study, via Gizmodo
While a sea-level rise of 1.2 inches may sound modest, researchers emphasize that it is enough to greatly magnify risks for coastal communities worldwide. Eric Rignot noted that the findings predict greater risk of and exposure for coastal flooding than anticipated in the coming decades.
Mouginot Ridge and the Threat of Unpinning
The topography beneath Thwaites slopes downward as it moves inland, exposing more ice to warm water as the glacier retreats. However, two underwater ridges currently act as natural barriers, pinning the ice and holding it back from flowing too rapidly into the ocean.
The new simulations reveal that melting processes at the grounding zone are accelerating the unpinning of ice from a raised section of seafloor called the Mouginot Ridge. Scientists estimate there is a 60 percent probability that the ice will break free from the ridge before the end of the century, with some runs placing the unpinning event as early as 2038.
Once the main trunk clears the Mouginot Ridge, the glacier is expected to retreat continuously across retrograde seafloor toward its next topographic high, known as the South Ridge. Experts outside the research team have taken notice of the updated modeling approach.
a real game changer for sea level forecasting from Thwaites.
Ted Scambos, senior research scientist at the Earth Science and Observation Center at the University of Colorado Boulder, via CP24
Nevertheless, independent geophysicists emphasize that significant knowledge gaps remain regarding sub-glacial processes. Robert Larter, a marine geophysicist at the British Antarctic Survey who was not involved in the research, noted that much remains to be learned about grounding zone mechanics before scientists can offer fully confident predictions on ice loss rates. To address these gaps, researchers are planning an expedition to the region in 2028 to deploy specialized instruments capable of documenting seawater flushing beneath the ice.
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The world’s largest glacier, Thwaites Glacier in West Antarctica, is melting much faster and could contribute twice as much to global sea level rise over the next century as previously expected.Here's what we know: https://t.co/ewJNrFRWC3 pic.twitter.com/nWIDVPTi3g
More on Thwaites Glacier
🚨 A giant glacier in Antarctica, roughly the size of Great Britain, is raising serious concerns among scientists over the potential impact on coastlines around the world — including the UK. Known as the ‘Doomsday Glacier’, Thwaites Glacier is losing ice as warmer ocean water… pic.twitter.com/GSXKHxbHrt
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