Thirty-three years of glacier grounding line retreat in Antarctica 1992-2025

The Grounding Line (GL) - the transition from ice grounded on the
continent and ice afloat in the ocean - is a sensitive indicator of
glacier stability and mass balance. Using differential SAR interferometry
from ERS-1/2, Sentinel-1, RADARSAT-1/2, RCM, ALOS PALSAR-2, COSMO-SkyMed,
and ICEYE, we assemble a continental scale record of grounding line
migration from 1992 to 2025. Over 77±10% of Antarctic coastal length, we
detect no GL migration. Stable areas include the vast Ross,
Filchner-Ronne, Amery and West ice shelves, and broad sectors of Coats,
Queen Maud, Enderby, and Princess Elizabeth Lands. Retreat is concentrated
in (i) the Antarctic Peninsula - 2-18 km along Larsen A-B and 2-6 km along
parts of GeorgeVI, and no change on Larsen C-D ice shelves; (ii) Wilkes
and GeorgeV lands - 6-10 km on Denman, Totten, Moscow, Frost, Holmes,
Mertz, Ninnis, and Cook, and 26 km on Vanderford; and (iii) West
Antarctica - 5-7-km on Ferrigno, Fox, and Venable, with extreme retreat in
the Amundsen and Getz sectors (Pine Island 33 km, Thwaites 26 km, Haynes
20 km, Pope 23 km, Smith 42 km, Kohler 12 km, East Getz 9 km toward Berry
18 km, Hull 14 km and Land 5 km). The ice sheet lost 12,820±1,873km2of
grounded ice in 1996-2025, or 442±64 km2/year, with 62% from West
Antarctica and 28% from East Antarctica. Retreat clusters in areas where
bathymetry channelizes warm Circumpolar Deep Water toward deep grounding
zones where beds are retrograde, except in the northeastern Antarctic
Peninsula. The results provide a harmonized benchmark for ice grounding
zone-based ice sheet models and identifies gateways where future retreat
is likely to accelerate.