8th November 2025 Glacier retreat is fastest ever seen Hektoria Glacier in Antarctica has undergone the fastest retreat of any land glacier on record, with nearly 50% collapsing in just two months.
A study published this week in Nature Geoscience reveals how a glacier on Antarctica's Eastern Peninsula underwent an astonishingly rapid collapse, ten times faster than is typically seen. The new research, led by the University of Colorado at Boulder, details how and why Hektoria Glacier lost 8.2 km (5 mi) of ice in just two months between November and December 2022. Hektoria Glacier is relatively small by Antarctic standards – covering a land area of only 115 mi² (298 km²) or about the size of Philadelphia – but a collapse of similar speed on larger Antarctic glaciers could have catastrophic implications for global sea level rise. Including the event previously described, Hektoria retreated by a total of 25 km (15.5 mi) in 15 months between early 2022 and mid-2023. The study authors found that its unusually flat bedrock and ice base allowed the glacier to lift off the ground once it had thinned enough, triggering accelerated calving.
Credit: Nature Geoscience
"When we flew over Hektoria in early 2024, I couldn't believe the vastness of the area that had collapsed," said Naomi Ochwat, lead author, and a postdoctoral researcher at the Cooperative Institute for Research in Environmental Sciences (CIRES). "I'd seen the fjord and notable mountain features in the satellite images, but being there in person filled me with astonishment at what had happened." Antarctica contains many so-called "tidewater" glaciers, which terminate in the ocean and lose mass primarily through the calving of icebergs. The topography of the land beneath tidewater glaciers is often varied. They may sit upon deep canyons, underground mountains, or big flat plains. In Hektoria's case, the glacier rested on bedrock and a flat plain of ice below sea level. Researchers previously found that 15,000-19,000 years ago, Antarctic glaciers atop ice plains retreated hundreds of metres per day, and this helped the team better understand Hektoria's rapid retreat. Easily destabilised When tidewater glaciers meet the ocean, they can go afloat, becoming buoyant on the ocean's surface rather than resting on solid ground. The point at which a glacier goes afloat is called the grounding line. Using several types of satellite data, the researchers discovered Hektoria had multiple grounding lines, which can indicate a flat topography underneath. Hektoria's icy bed – combined with a breakup of stationary sea ice holding it back – caused a large part of the glacier to float free. Ocean forces then opened crevasses upward from below, which met fractures descending from the surface, splitting the ice tongue apart. Continued thinning and rising buoyancy lifted the glacier's front end, driving yet more icebergs into the sea. "This implies that marine-terminating glaciers with ice plain bed geometry can be easily destabilised," the study authors conclude.
Satellite data at frequent time intervals, along with seismic instruments, created a robust picture of the glacier, its topography, and its retreat. "If we only had one image every three months, we might not be able to tell you that the glacier lost two and a half kilometres in two days," Ochwat said. "Combining these different satellites, we can fill in time gaps and confirm how quickly the glacier lost ice." Ice plain topographies have been detected across numerous glaciers in Antarctica, and the research on Hektoria will help scientists anticipate and forecast potential rapid retreat across the continent. "Hektoria's retreat is a bit of a shock – this kind of lightning-fast retreat really changes what's possible for other, larger glaciers on the continent," said CIRES Senior Research Scientist Ted Scambos. "If the same conditions set up in some of the other areas, it could greatly speed up sea level rise from the continent."
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