The planet’s two major ice sheets have together lost 11,309 billion tonnes of ice over 45 years.
This figure comes from a broad review published in Scientific Data. Researchers combined 42 independent estimates obtained using satellites. These have monitored Greenland since 1972 and Antarctica since 1979. The measurements rely in particular on ice velocity, elevation and variations in Earth’s gravitational field.
Mass changes in the Greenland ice sheet measured by the GRACE and GRACE-FO missions, with ice-flow lines.
Credit: NASA/JPL-Caltech.
Between 1979 and 2023, the cumulative losses from Greenland and Antarctica raised average ocean levels by 31.4 mm. Three centimetres may seem modest. Yet this rise adds to other causes of rising sea levels, notably the expansion of water as it warms and the melting of glaciers outside these two ice sheets.
An ice sheet receives snowfall, but it also loses material at the surface and through its glaciers. These can accelerate and transport more ice toward the ocean. This movement accounted for 84% of the total loss measured in the study.
Greenland lost approximately 6,215 billion tonnes of ice between 1972 and 2023. Close to balance at the beginning of this period, its losses subsequently accelerated: they averaged 264 billion tonnes per year during the 2010s, compared with around 60 billion tonnes in the 1980s.
Mass changes in the Antarctic ice sheet measured by the GRACE and GRACE-FO missions, with ice-flow lines.
Credit: NASA/JPL-Caltech.
Antarctica, for its part, lost approximately 4,780 billion tonnes between 1979 and 2023. However, the situation is not the same everywhere. In the eastern part of the continent, heavy snowfall in 2022 and 2023 temporarily increased the ice mass. This offset part of the persistent losses observed in the west.
This difference explains a result that might seem surprising. Between 2020 and 2023, Antarctica lost ice at more than three times a slower rate than during the 2010s. This does not mean that the overall trend has reversed: over the full 45 years studied, the balance remains clearly negative.
The new estimate brings together data from 27 satellite missions. By comparing several measurement methods, researchers can reduce the uncertainties specific to each one. This monitoring must now continue, because ice sheets remain one of the main sources of uncertainty when forecasting future sea-level rise.