Greenland and Antarctica Lose 11.3 Trillion Tons of Ice

Greenland and Antarctica lost a combined 11.3 trillion metric tons of ice between 1979 and 2023, raising global sea levels by 3.14 cm, according to a new study based on data from 27 satellite missions.

The study was conducted by the Ice Sheet Mass Balance Inter-comparison Exercise, an international team of polar scientists, using the longest satellite record of ice-sheet changes gathered to date. Researchers said the findings provide further evidence of the effects of human-induced climate change.

Greenland accounted for about 60% of the total ice loss and Antarctica 40%, even though Greenland is about one-eighth the size of Antarctica. Ice sheets now account for about a quarter of global sea-level rise, while every additional centimeter puts two to three million people at risk of annual coastal flooding.

The expanded satellite record confirms that ice losses began in the 1990s and have increased since then. Between the 1980s and the 2010s, the rate quadrupled.

Ice loss slowed between 2020 and 2023, but researchers said this appeared to be a short-term variation rather than a reversal of the long-term trend. Unusually high snowfall in East Antarctica offset some glacier losses elsewhere on the continent, while relatively mild summers in Greenland substantially reduced surface melting.

Some 84% of the ice lost came from glaciers flowing more quickly into the ocean rather than from melting at the surface, indicating that the long-term trend is being driven by the ice sheets’ response to a warming ocean.

The 3.14 cm of sea-level rise attributed to ice losses in Greenland and Antarctica puts an additional six to nine million people at risk of coastal flooding and erosion worldwide.

(Reuters, bak)