Warm ocean water is infiltrating miles beneath the bedrock of West Antarctica's Thwaites Glacier, triggering a more rapid retreat and significantly worsening future sea-level rise forecasts. Researchers from the University of California and NASA's Jet Propulsion Laboratory developed an advanced ice sheet model to analyze the vulnerable glacier, often referred to as the Doomsday Glacier. Published in Nature Communications, the new findings project that Thwaites alone could contribute up to 1.2 inches of sea-level rise by the year 2100, even if no further climate warming occurs.
For decades, scientists struggled to reconcile computer forecasts of ice flow with real-world satellite observations of Antarctica. Traditional models treated the grounding line—where ice shifts from resting on bedrock to floating on the ocean—as a narrow and relatively stable boundary. However, by analyzing synthetic aperture radar data from the ICEYE satellite constellation spanning the last two decades, the research team detected dramatic fluctuations along the glacier's main trunk.
The data revealed that pressurized seawater penetrates several miles underneath the grounded ice, lifting the massive sheet in response to tidal movements. This hidden intrusion carries ocean heat far inland, accelerating melting at the base of the glacier and pushing it away from stabilizing underwater ridges. According to study co-author Eric Rignot, this newly understood underside vulnerability means the updated physical model generates projections that are twice as large as previous estimates, heightening coastal flood risks worldwide.
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