Overview
- The Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) reported on Wednesday that Greenland and Antarctica shed 11,309 billion tonnes of ice from 1979 to 2023, adding about 31.4 millimetres (3.14 cm) to global sea level.
- About 84% of that loss resulted from dynamic ice discharge—glaciers accelerating and dumping ice into the ocean—rather than from surface melting caused by warm air.
- Ice-loss rates rose sharply from the 1990s into the 2010s, with Greenland’s annual loss climbing from roughly 60 to 264 billion tonnes and Antarctica’s from about 48 to 202 billion tonnes per year.
- A temporary slowdown from 2020–2023 was driven by record East Antarctic snowfall and milder Greenland summers, but scientists say this is short-term variability and not a reversal of the long-term trend.
- Researchers warn the ice sheets remain the largest unknown in long-term sea-level forecasts and call for continuous satellite missions and coordinated modelling to sharpen risk estimates for millions in low-lying coastal areas.