The future of one of Antarctica's most iconic glaciers could be far more dramatic than scientists previously thought. Using satellite calibrated ice sheet models, a team of researchers from the University of Edinburgh found that the Thwaites Glacier in West Antarctica could be shedding 180–200 gigatonnes of ice per year by 2067—a rate roughly comparable to the entire Antarctic ice sheet's current mass loss. That would represent a stunning acceleration in ice loss from a single glacier and underlines urgent concerns about future contributions to sea level rise.

One of the key findings of the new study, published in Geophysical Research Letters, is that the way models are “trained” against observations strongly influences their long-term predictions. Models that were constrained using satellite measurements of surface elevation change (how the height of the glacier is decreasing over time) projected the largest future mass losses. Those projections suggest that by 2067, the rate of ice loss from Thwaites Glacier could equal what the entire Antarctic ice sheet currently contributes to sea level rise each year.

By contrast, calibrating models using only ice velocity data (how fast ice is moving toward the ocean) produced lower and more stable future loss rates. This discrepancy shows that what data scientists choose to emphasize when calibrating models can dramatically change the future picture scientists paint for Thwaites Glacier. While both approaches capture important behaviors, the models incorporating surface elevation changes appear to match the recent observed patterns of thinning most consistently.