Greenland and Antarctica lost 11.3 trillion tonnes of ice between 1979 and 2023. That loss raised global sea level by 3.14 centimetres. The two ice sheets are responsible for around a quarter of global sea-level rise. Most of the loss did not come from surface melting; it came from faster-flowing glaciers carrying ice directly into the ocean.
The numbers come from the Ice Sheet Mass Balance Intercomparison Exercise, or IMBIE, a collaboration supported by ESA and NASA. The team drew on 27 satellite missions, including ESA's CryoSat, the Copernicus Sentinels, the US-German Grace missions and early Landsat missions, and combined 42 independent surveys into one consistent record. It starts in 1972 for Greenland and 1979 for Antarctica, making it the longest satellite-era record of ice-sheet change ever assembled. The results were published in the journal Scientific Data.
IMBIE exists because satellites do not measure ice in the same way. Some altimeters track the height of the ice surface, some measure Earth's gravity field, and radar and optical sensors track glacier motion. The team combines independent estimates of ice-sheet mass balance, the gap between ice gains and losses, and accounts for differences between satellite data, techniques and observation periods. The goal is to separate genuine change in the ice sheets from apparent change caused by how the ice was measured.
Most of the ice left through glacier flow, not surface melt
Between 1979 and 2023, the combined ice loss from the two ice sheets was 11.3 trillion tonnes. Greenland contributed 1.81 centimetres of sea-level rise; Antarctica contributed 1.33 centimetres. Of the total, 84% came from glaciers accelerating and discharging more ice into the ocean, while 16% came from melting at the surface.
Inès Otosaka of Northumbria University led the study. She said the record shows how the ice sheets have changed across half a century, and that the long-term trend comes from how the ice sheets respond to a warming ocean. Glacier flow, not surface warmth, is the dominant mechanism of loss.
Ice losses began to accelerate sharply from the 1990s onwards. Greenland was close to balance in the 1970s, then saw annual losses rise from around 60 billion tonnes in the 1980s to 264 billion tonnes in the 2010s, a decade with repeated episodes of extreme summer melting. Antarctica moved along a similar path, with annual losses rising from around 48 billion tonnes in the 1980s to 202 billion tonnes in the 2010s. Unlike Greenland, Antarctica's net loss was driven entirely by ocean-driven melting and accelerating outlet glaciers. Ice discharge in West Antarctica has increased in every decade of the satellite record, led by Pine Island and Thwaites glaciers.
The recent slowdown is a variation, not a reversal
Between 2020 and 2023, overall ice loss slowed. Unusually high snowfall across East Antarctica added enough ice to offset some losses elsewhere on the continent. In Greenland, a run of relatively mild summers cut surface melting by roughly half. Scientists caution that these are short-term variations, not a reversal of the long-term trend. The ice sheets are still losing ice overall, with year-to-year fluctuations.
Andrew Shepherd, founder of IMBIE and also at Northumbria University, put the sea-level number in human terms. Just over three centimetres of rise, he said, puts another six to nine million people at risk of coastal flooding and erosion. Global assessments like IMBIE exist to help communities plan for that risk.
For someone planning a polar voyage, the record is a way to tell climate signal from weather noise. A cold summer or a heavy snowfall year does not mean the ice sheets have recovered. The useful question to put to an operator is whether planning assumes stable ice conditions; the satellite record says the ice sheets have not had them for half a century.