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Research & Developments is a blog for brief updates that provide context for the flurry of news that impacts science and scientists today.
A new study of Antarctica has found that since 1996, its ice sheet has lost 12,820 square kilometers (nearly 5,000 square miles) of ice—nearly enough to cover the state of Connecticut, or 10 cities the size of Greater Los Angeles.
The study, published today in Proceedings of the National Academy of Sciences, evaluated the retreat of the ice sheet’s grounding line over the past 30 years. A grounding line is the point at which continental ice (grounded on bedrock) meets a floating ice shelf, and as such serves as a good measure of the advance and retreat of ocean-terminating glaciers.
Since 1992, scientists have been monitoring the movement of grounding lines with synthetic aperture radar (SAR), the “gold standard for documenting ice sheet stability,” said Eric Rignot, a glaciologist at the University of California, Irvine, and coauthor of the new paper, in a statement.
Data from multiple SAR-equipped satellites showed that about 77% of Antarctica’s coastline remains stable, but the unstable portions—West Antarctica, the Antarctic Peninsula, and portions of southern East Antarctica—are losing ice much faster as Earth’s climate warms.
Grounding line changes from 1992-2025 show quicker ice loss along West Antarctica, parts of the Antarctic Peninsula, and southern East Antarctica. Credit:
Rignot et al. 2026,
https://doi.org/10.1073/pnas.2524380123
Glaciers in West Antarctica have retreated the farthest: In the last 30 years, Pine Island Glacier retreated 33 kilometers (20.5 miles), Thwaites Glacier—often called the Doomsday Glacier for its potential contribution to sea level rise—retreated about 26 kilometers (16.2 miles), and Smith Glacier retreated about 42 kilometers (26.1 miles).
Related
• Read the paper: Thirty Years of Glacier Grounding Line Retreat in Antarctica
“Where warm ocean water is pushed by winds to reach glaciers, that’s where we see the big wounds in Antarctica,” Rignot said. Thwaites and Pine Island glaciers, for instance, began their retreats in the 1940s, when a prolonged El Niño event likely brought warmer-than average temperatures to the Southern Ocean.
Though warm ocean waters mostly explain the retreats along West Antarctica, large retreats along the northeast side of the Antarctic Peninsula are more difficult to interpret, according to the authors. There, “we don’t have evidence for warm water,” Rignot said. “Something else is acting—it’s still a question mark.”
The data provided in the new paper offer future ice sheet scientists critical benchmarks to test how accurate their own models and projections of Antarctic ice loss are, Rignot said. “If a model can’t reproduce this record, the modeling team will need to go back to the drawing board.”
—Grace van Deelen (@gvd.bsky.social), Staff Writer
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