The most comprehensive assessment yet of changes in the world's polar ice sheets has found that Greenland and Antarctica have together lost more than 11 trillion tonnes of ice since the late 20th century, contributing significantly to global sea level rise.
The international study, led by researchers from Northumbria University and supported by NASA, combined evidence from 42 independent satellite surveys spanning more than five decades. Drawing on observations from 27 satellite missions, the team reconstructed ice sheet changes in Greenland back to 1972 and Antarctica back to 1979.
Their findings show that the two ice sheets lost an estimated 11,309 billion tonnes of ice between 1979 and 2023. This ice loss contributed approximately 31.4 millimetres to global sea levels, with Greenland accounting for the larger share and Antarctica adding about 13 millimetres.
Researchers found that the dominant driver of ice loss was not surface melting, but the acceleration of glaciers flowing into the ocean. Around 84 percent of the total loss resulted from faster glacier discharge, while surface melting accounted for only 16 percent. The result highlights the growing influence of a warming ocean on the stability of polar ice sheets.
The study also documents a sharp increase in ice loss rates beginning in the 1990s. Greenland's annual losses rose more than fourfold between the 1980s and the 2010s, while Antarctica experienced a similar acceleration.
Although ice loss slowed somewhat between 2020 and 2023, scientists caution that this reflects short-term weather conditions rather than a reversal of the long-term trend. Heavy snowfall in East Antarctica and relatively mild summers in Greenland temporarily offset some losses, but the overall trajectory remains one of decline.
Today, Greenland and Antarctica are responsible for roughly one quarter of all global sea level rise. Researchers say the expanded satellite record provides a stronger foundation for projecting future changes and understanding the risks facing millions of people living in vulnerable coastal regions.