Antarctic Drilling Project Reaches Record Depth to Inform Ice Sheet Stability Projections

The international SWAIS2C drilling initiative concluded a significant phase of its 2025/2026 field season by successfully penetrating 228 meters into the geological sediments beneath Crary Ice Rise in the Ross Sea. This achievement surpassed the project’s initial 200-meter objective, securing a critical geological record of the West Antarctic Ice Sheet’s (WAIS) history, which may extend back millions of years. The complex operation required the research team to first drill through 523 meters of overlying ice to reach the bedrock sediments, with the entire site situated approximately 700 kilometers from the logistical center at Scott Base.

The core data recovered is considered essential for refining scientific assessments regarding the WAIS’s susceptibility to a global warming threshold of +2°C, a benchmark established under the United Nations Paris Agreement. The research, supported by the International Continental Scientific Drilling Project (ICDP) and involving collaboration among ten nations, aims fundamentally to pinpoint the WAIS ‘tipping point’ that precedes irreversible disintegration. Full collapse of the WAIS, according to current projections, could contribute between four and five meters to global sea levels.

Initial analysis of the retrieved sediment core layers is already yielding evidence of past environmental shifts that correlate with historical warming periods. These geological findings are intended to rigorously test and calibrate contemporary climate models, thereby enhancing the precision of future sea-level contribution projections. The fieldwork was jointly directed by Co-Chief Scientists Molly Patterson of Binghamton University and Huw Horgan from Te Herenga Waka – Victoria University of Wellington and ETH Zurich, who oversaw the challenging Antarctic endeavor.

The SWAIS2C project, an acronym for Sensitivity of the West Antarctic Ice Sheet to 2°C, involves over 120 scientists from approximately 50 international research organizations across ten countries, including the United States, Germany, Australia, and Japan. Project management and logistics are being spearheaded by Earth Sciences New Zealand, Te Herenga Waka – Victoria University of Wellington, and Antarctica New Zealand. This undertaking is the first ICDP project to be hosted in Antarctica, following precedents like the ANDRILL program.

Researchers will specifically examine the sediment for microfossils of marine algae, as their presence would indicate open ocean conditions resulting from the retreat of the protective Ross Ice Shelf. The Ross Ice Shelf functions as a critical buttress, slowing the flow of glaciers toward the sea. This context is vital, considering that global temperatures during the last interglacial period, approximately 125,000 years ago, were 1–1.5°C warmer than pre-industrial levels, potentially leading to a global sea level six to nine meters higher. The success of this drilling campaign, which overcame prior technical setbacks, builds confidence for future modeling efforts to anticipate the rate and magnitude of ice sheet changes under various greenhouse gas scenarios.