Thwaites Glacier Could Add 30 Millimeters to Seas by 2100

A new model of Antarctica’s Thwaites Glacier projects that it could add up to 30 millimeters to global sea levels by 2100, roughly twice previous estimates for the glacier. The projection comes from research by scientists at the University of California, Irvine, and NASA’s Jet Propulsion Laboratory, published October 12 in Nature Communications. The model accounts for melting across a broad grounding zone, where tides can move seawater beneath ice still resting on the seabed. Rather than treating the boundary between grounded and floating ice as a narrow, fixed line, researchers incorporated the zone’s tidal shifts and the seawater intrusion they enable. The study says this approach better reproduces observed changes in the glacier than traditional models. Thwaites is already an important contributor to global sea-level rise. The new estimate concerns the glacier alone; it does not mean total sea-level rise worldwide will double. Researchers say the model projects up to 30 millimeters of contribution by century’s end even without additional climate warming. In simulations that used a 46-kilometer-wide grounding zone, the researchers estimated a 60% probability that Thwaites...