Understanding Thwaites Glacier's recent history and the processes driving its retreat is crucial for predicting Antarctic contributions to future sea-level rise. This study uses geophysical data from an autonomous underwater vehicle (AUV) to document the ocean-floor imprint of past retreat from a seabed promontory. Patterns of back-stepping sedimentary ridges, formed daily by tidal lifting and settling at the grounding line, reveal a retreat rate of >2.1 km per year—twice the satellite-observed rate. The findings suggest sustained pulses of rapid retreat in the past two centuries, with similar pulses likely in the near future as the grounding zone migrates off stabilizing high points on the seafloor.

Alastair G. C. Graham, Anna Wåhlin, Kelly A. Hogan, Frank O. Nitsche, Karen J. Heywood, Rebecca L. Totten, James A. Smith, Claus-Dieter Hillenbrand, Lauren M. Simkins, John B. Anderson, Julia S. Wellner, Robert D. Larter