2026-03-02 カリフォルニア大学アーバイン校（UCI）
A study led by UC Irvine researchers using 30 years of satellite data has shown that 23 percent of Antarctica’s ocean-reaching glaciers are undergoing rapid retreat. Worst hit are glaciers in the vicinity of the Amundsen Sea and Bellinghausen Sea in West Antarctica and glaciers in Wilkes Land in East Antarctica. Rignot research group / UC Irvine
＜関連情報＞
- https://news.uci.edu/2026/03/02/antarctica-has-lost-10-times-the-size-of-greater-los-angeles-in-ice-over-30-years/
- https://www.pnas.org/doi/10.1073/pnas.2524380123
南極の氷河の接地線が30年にわたって後退 Thirty years of glacier grounding line retreat in Antarctica
Eric Rignot, Bernd Scheuchl, Jean Baptiste Barre, +13 , and Michael Wollersheim
Proceedings of the National academy of Sciences Published:March 2, 2026
DOI:https://doi.org/10.1073/pnas.2524380123
Significance
Three decades of satellite synthetic aperture radar interferometry show that about 77% of Antarctica’s grounding line has remained stable. Grounding-line retreat is concentrated in the northeast and southwest Antarctic Peninsula, Wilkes and George V Lands of East Antarctica, and the Bellingshausen Sea, Amundsen Sea, and Getz Ice Shelf sectors of West Antarctica, where retreat ranges from 10 to more than 40 km. The greatest retreat occurs where deep troughs permit warm Circumpolar Deep Water access and where beds deepen inland, indicating sustained mass loss from vulnerable sectors. Slower retreat occurs where warm-water access is limited and beds shoal inland. These continent-scale grounding-zone observations provide an important benchmark for evaluating and improving next-generation ice-sheet models.
Abstract
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 synthetic aperture radar interferometry from ERS-1/2, Sentinel-1, RADARSAT-1/2, RADARSAT Constellation Mission, 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. Retreat is concentrated in i) the Antarctic Peninsula–2 to 18 km along Larsen A-B and 2 to 6 km along parts of George VI; ii) Wilkes and George V lands–6 to 10 km on Denman, Totten, Moscow, Frost, Holmes, Mertz, Ninnis, and Cook, and 26 km on Vanderford; and iii) West Antarctica–5 to 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 ± 1,873 km2 of grounded ice in 1996–2025, or 442 ± 64 km2/y, 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.
