Previous West Antarctic Ice Loss Indicates Other Sources of Sea-level Rise As Well

Nature, 29 January 2025

The largest source of uncertainty in the rate and extent of sea-level rise with high emissions is the fate and stability of the West Antarctic Ice Sheet. Understanding how this region reacts to higher temperatures is critical for predicting future sea-level rise. In this study, researchers used ice core records to measure how West Antarctica was affected by increased global temperatures 125,000 years ago, during the Last Inter-Glacial (LIG), when polar regions were about 3°C warmer than pre-industrial, with global sea levels up to 10 meters higher than today. They discovered that the West Antarctic Ice Sheet shrunk to roughly half of its modern-day mass during this period; and that the Ronne Ice Shelf, which supports inland glaciers in West Antarctica, survived this past period of warming. These findings suggest that West Antarctica, which holds total about 4 meters sea-level rise, could not have been the only significant source of higher sea levels during this period, indicating that Greenland and/or East Antarctica (the only other regions with this much ice) must have lost mass during the Last Interglacial as well.

These important findings help improve forecasts of what could happen to ice sheets as Earth’s climate warms. A presentation by the authors will be recorded and shared here in next week’s Capsules.

Full paper: https://www.nature.com/articles/s41586-024-08394-w
Coverage by the British Antarctic Survey: https://www.bas.ac.uk/media-post/ancient-antarctic-ice-loss-offers-insights-into-future-climate-scenarios/