Deep beneath Antarctica’s ice, scientists have uncovered a geological archive that could reshape predictions of future sea-level rise.
Working roughly 700 kilometers from the closest Antarctic research stations, the team drilled through 523 meters of solid ice at Crary Ice Rise, located along the edge of the West Antarctic Ice Sheet. Beneath the ice, they recovered a 228-meter-long core made up of layered mud and rock. These sediments preserve a long record of environmental change during earlier warm phases in Earth’s history, offering crucial evidence for estimating how quickly ice in the region could melt as the planet warms.
If the West Antarctic Ice Sheet were to collapse entirely, scientists estimate that global sea levels would climb by four to five meters. Until now, predictions about how the ice sheet might react to additional warming have relied largely on satellite data and sediment records gathered near the ice margin, beneath floating ice shelves, within sea ice, and across the Ross Sea and Southern Ocean۔
The newly recovered core was drilled as part of the international SWAIS2C project (Sensitivity of the West Antarctic Ice Sheet to 2°C). It was collected at Crary Ice Rise, an ice dome anchored at the inner edge of the Ross Ice Shelf. Unlike previous records, this core provides direct and detailed evidence of how the ice sheet’s margin behaved during earlier warm intervals.
23 Million Years of Climate History Above 2°C
“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.”
Initial age estimates were made at the drilling site by identifying microscopic fossils from marine organisms preserved in several sediment layers. Researchers from 10 countries involved in the SWAIS2C project will now carry out more detailed analyses to confirm and refine the timeline.
As drilling progressed deeper below the ice sheet, the team extracted sections of core measuring up to three meters at a time. The sediments showed remarkable diversity, ranging from fine mud to compact gravel containing larger embedded rocks.
