Record-breaking sediment core may help predict Antarctic ice loss

Researchers drilled through 523 meters of ice to extract a 228-meter sediment core that provides a comprehensive record of past warm periods in West Antarctica.

Published on Feb. 18, 2026

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A team of researchers from ten countries has recovered a remarkable 228-meter sediment core from beneath the ice of West Antarctica's Crary Ice Rise. This record-breaking core provides a comprehensive record of past warm periods in the region, which is crucial for estimating how quickly the West Antarctic Ice Sheet might melt in a warmer future. The sediment core documents environmental conditions during earlier warm periods, including evidence of open ocean and ice-free conditions, indicating potential past collapse of the ice sheet.

Why it matters

If the West Antarctic Ice Sheet were to melt completely, global sea levels would rise by 4-5 meters. Until now, projections of how the ice sheet might respond to further warming have relied mainly on satellite observations and geological records collected near the ice sheet. This new sediment core provides direct evidence of the ice sheet's behavior during past warm periods, which is crucial for improving predictions of future ice loss and sea level rise.

The details

The sediment core was drilled as part of the international SWAIS2C project (Sensitivity of the West Antarctic Ice Sheet to 2°C) at Crary Ice Rise, on the margin of the West Antarctic Ice Sheet. The core contains a striking variety of sediment types, from fine-grained muds to gravels with larger rocks, indicating past periods of open ocean, ice shelf, and ice-free conditions in the region. Shell fragments and marine organism remains suggest parts of the region were once ice-free. Determining the timing of these past ice retreats and the environmental factors that drove them is a central focus of the research team.

  • The sediment core spans the past 23 million years, including time periods when Earth's global average temperatures were significantly higher than 2°C above pre-industrial levels.

The players

SWAIS2C

An international research project focused on understanding the sensitivity of the West Antarctic Ice Sheet to 2°C of global warming.

Huw Horgan

SWAIS2C Co-Chief Scientist and researcher at Te Herenga Waka – Victoria University of Wellington, ETH Zurich and WSL.

Molly Patterson

SWAIS2C Co-Chief Scientist and Professor of Geology at Binghamton University, USA.

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What they’re saying

“This record will give us critical insights about how the West Antarctic Ice Sheet and Ross Ice Shelf is likely to respond to temperatures above 2°C. Initial indications are that the layers of sediment in the core span the past 23 million years, including time periods when Earth's global average temperatures were significantly higher than 2°C above pre-industrial.”

— Huw Horgan, SWAIS2C Co-Chief Scientist

“We saw a lot of variability. Some of the sediment was typical of deposits that occur under an ice sheet like we have at Crary Ice Rise today. But we also saw material that's more typical of an open ocean, an ice shelf floating over ocean, or an ice-shelf margin with icebergs calving off.”

— Molly Patterson, SWAIS2C Co-Chief Scientist

What’s next

The SWAIS2C team will now refine and confirm the age of the sediment core records, as well as collaborate to unravel the climate secrets hidden in the core. With the drilling system proven under tough Antarctic conditions, the team is looking ahead to plan future drilling to continue learning about the sensitivity of the West Antarctic Ice Sheet to global warming.

The takeaway

This record-breaking sediment core provides a crucial new source of evidence about past warm periods in West Antarctica, which will help improve predictions of how the region's ice sheet might respond to future climate change and sea level rise. The successful drilling operation also demonstrates the technical capabilities of the international SWAIS2C team to push the boundaries of Antarctic science.