Thwaites Glacier Melting Could Raise Sea Levels More Than Expected

 

One of Antarctica’s largest glaciers may contribute more to rising oceans than scientists previously estimated. New research on Thwaites Glacier, located in West Antarctica, suggests that the processes driving its retreat have been underestimated in some existing climate models.

Often called the Doomsday Glacier, Thwaites has attracted scientific attention because of its size and potential influence on global sea levels. The latest findings indicate that Thwaites Glacier melting could contribute up to 30 millimeters of sea-level rise by 2100, approximately twice some earlier projections.

The results highlight the importance of understanding what happens beneath the ice, where relatively warm seawater can accelerate melting.

The Hidden Process Beneath the Ice

Thwaites Glacier extends from the Antarctic ice sheet into the ocean. Part of its ice rests on the seabed, while the seaward section floats on the water as an ice shelf.

The point where grounded ice transitions into floating ice is known as the grounding line. Researchers have found that this transition is not always a narrow, fixed boundary. Instead, it can form a broad zone where ocean water moves beneath the ice as tides lift and lower it.

This movement allows seawater to penetrate farther inland, increasing melting beneath the glacier. By accounting for this process, researchers developed a model that more closely reproduced observed changes in the glacier between 1996 and 2023.

Why Earlier Projections May Have Been Too Low

Many previous models simplified the transition between grounded and floating ice. According to the new study, representing the grounding zone as a region several kilometers wide better reflects the physical processes taking place beneath Thwaites.

The revised model suggests that Thwaites Glacier melting could cause the ice to detach from a stabilizing underwater ridge earlier than previously anticipated. The model indicates that this detachment could begin as early as 2038.

The ridge currently helps restrain the glacier’s movement toward the ocean. If the ice loses that support, it could retreat more rapidly along the sloping seabed.

However, these results are model-based projections, not a guarantee that a particular event will occur in a specific year. Scientists still need additional observations to understand the complex environment beneath the glacier.

What Rising Seas Could Mean for Coastal Areas

The projected contribution of up to 30 millimeters by 2100 may sound modest, but additional sea-level rise can increase the risks associated with coastal flooding and storm surges.

Low-lying communities, coastal infrastructure, and vulnerable ecosystems could face greater pressure as ocean levels rise. Thwaites also acts as a barrier that helps restrain ice farther inland, meaning its long-term destabilization could have wider implications for Antarctica.

A complete collapse would be a much larger, long-term concern and should not be confused with the study’s estimate for this century.

Scientists Continue Investigating the Glacier

Researchers plan to collect more direct measurements of the processes occurring beneath Thwaites. Such observations could help refine models and improve forecasts of future sea-level changes.

The findings show why understanding Thwaites Glacier melting is important for climate research and coastal planning. Although uncertainties remain, improved modeling can help scientists identify risks earlier and give communities better information for preparing for a changing climate.