Thwaites Glacier Sea-Level Rise Projections Double in New Study
Tidal seawater intrusion beneath the glacier could accelerate ice loss significantly by 2100.
1Revised Sea-Level Projections
New modelling published in Nature Communications suggests the Thwaites Glacier could contribute up to 30mm to global sea-level rise by 2100. This estimate is approximately double previous projections. Researchers from UC Irvine and NASA reached these figures by accounting for seawater moving beneath the ice, even without additional climate warming scenarios.
2Tidal Pumping Mechanism
The study replaces the traditional narrow boundary model with a broad, tidally shifting grounding zone. As tides rise, pressurized seawater lifts the ice and penetrates several kilometres inland. This warm water melts the glacier from below, a process that satellite observations confirm is occurring across a wide, irregular transition area.
3Mouginot Ridge Stability
The glacier currently relies on the underwater Mouginot Ridge to maintain its position. Simulations with a 4–6km wide grounding zone indicate a 60 per cent probability that Thwaites will detach from this feature by 2100. Once contact is lost, the glacier would likely retreat toward deeper, more vulnerable inland underwater terrain.
4Broader Antarctic Implications
While the 30mm projection applies specifically to Thwaites, the glacier acts as a critical stabilizer for the West Antarctic ice sheet. The entire sheet contains enough ice to raise global sea levels by over 3 metres. Thwaites alone holds enough ice to cause a 65cm rise if it were lost entirely.
5Building on Satellite Data
This research expands upon a 2024 study led by Eric Rignot, which utilized satellite radar to map seawater intrusion. That earlier work identified a 6km wide grounding zone at the centre of the glacier. By incorporating these specific intrusion patterns, the new model more accurately reproduces observed changes in the glacier's structure.
6Need for Direct Measurement
Independent experts like Ted Scambos and Robert Larter emphasize that while the model improves forecasting, the sub-glacial environment remains complex. They note that direct measurements beneath the ice are still required to confirm these processes. Current models struggle to fully capture interactions between meltwater drainage, sediments, and tidal pumping mechanisms.
7Role of Emissions Cuts
The study's projections assume no additional warming, but researchers stress that emissions reductions remain vital. The International Thwaites Glacier Collaboration suggests that cuts consistent with the Paris Agreement could delay the most severe acceleration of ice loss. Sustained climate action is essential to push these critical tipping points beyond the current century.
8Future Monitoring Priorities
The findings highlight an urgent need for continued monitoring of grounding zone processes. As coastal communities face increased flood risks, improving the precision of these models becomes a priority for climate scientists. Future research must focus on the unresolved interactions between tidal pumping and the physical stability of the Antarctic ice sheet.
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