Antarctica’s ‘Doomsday Glacier’ could unleash a bigger threat than previously feared, with new research warning that it could drive twice as much sea-level rise by 2100 as earlier models predicted. According to CNN, the study found that warm ocean water is penetrating several kilometres beneath Thwaites Glacier, accelerating melting in a zone that conventional ice-sheet models have largely overlooked. Researchers from the University of California, Irvine, and NASA’s Jet Propulsion Laboratory said accounting for this process pushed the glacier’s projected contribution to sea-level rise to up to 30 mm by 2100, roughly twice previous estimates.

The glacier’s stability could be further threatened if it loses contact with the Mouginot Ridge, an underwater feature that currently helps hold back its retreat. Lead researcher Mattia Poinelli said simulations incorporating a 4–6 kilometre-wide grounding zone indicate a 60 per cent probability of the glacier becoming detached from the ridge by 2100.

Co-author Eric Rignot warned that existing projections had struggled to capture the speed of ice loss because key physical processes were missing from earlier models. Thwaites Glacier, which is roughly the size of Britain, is one of Antarctica’s fastest-changing glaciers and a major contributor to global sea-level rise. It has retreated around 25 kilometres in its fastest-flowing western sector since 1996, while its ice loss currently accounts for about 4 per cent of global sea-level rise. According to the International Thwaites Glacier Collaboration,if the glacier were to collapse entirely, it could eventually raise global sea levels by around 65 centimetres.

Why Thwaites Glacier is shrinkingThe primary driver of Thwaites Glacier’s retreat is relatively warm ocean water melting the ice from below, a process intensified by climate change. Warm, salty water reaches the glacier’s floating ice shelf and grounding zone, where the ice meets the seabed, thinning the ice and weakening the structure that slows the flow of inland ice towards the ocean, according to the British Antarctic Survey. As the glacier thins, its grounding line retreats inland, exposing more ice to seawater.

The seabed beneath parts of Thwaites also slopes deeper towards the Antarctic interior, allowing ocean water to penetrate further beneath the ice and potentially accelerate the retreat. NASA research has identified this feedback mechanism as a major reason for concern. How its retreat could affect the climateThe most immediate global consequence would be rising sea levels as more land-based ice flows into the ocean. This would increase the risk of coastal flooding, erosion and storm-surge damage, particularly in low-lying coastal regions.

If Thwaites retreats substantially, it could also destabilise neighbouring glaciers, increasing the potential contribution from the wider West Antarctic Ice Sheet. The effects could extend beyond sea levels.

Large quantities of freshwater entering the Southern Ocean could alter its salinity and density, potentially affecting ocean circulation and the movement of heat and nutrients. Can cutting emissions slow the Doomsday Glacier’s retreat? Scientists say the most effective way to limit further melting is to rapidly cut greenhouse gas emissions and curb global warming, which is heating the ocean water responsible for melting Thwaites Glacier from below. Reducing emissions from fossil fuels and accelerating the shift to low-carbon energy could limit additional ocean warming and reduce the risk of more severe ice loss.A 2026 study led by the British Antarctic Survey found that Thwaites could continue losing ice for at least 150 years even when ocean-driven melting was switched off in simulations.

Researchers say there is no proven intervention that can quickly stop the glacier’s retreat. The priority is to limit further warming while preparing for unavoidable sea-level rise through stronger coastal protection, improved flood planning and restoration of natural barriers such as mangroves.