PNAS, 6 July 2026<\/p>\n
Antarctic ice shelves act as natural barriers that slow the flow of land ice into the ocean. As fractures develop and deepen, these ice shelves become weaker, allowing glaciers to flow faster and increasing Antarctica’s contribution to sea-level rise. Most current ice-sheet models do not account for this process. Using a model that simulates how fractures develop and weaken ice shelves in the Amundsen Sea Embayment of West Antarctica, the researchers found that fracture-driven weakening could increase sea-level contributions by up to 4.5 times by 2300 compared with models that do not include these processes. Even if no new fractures form, existing cracks alone commit the region to 50-130% more ice loss than projections that assume intact ice shelves. The study also found that deep fractures originating from beneath the ice shelves have a much greater influence on future ice loss than surface cracks. These findings show that fracture-driven weakening is an important process that should be included in ice-sheet models to improve projections of Antarctica’s future contribution to sea-level rise.<\/p>\n