Earth lost 12.5 trillion tons of ice from Greenland and Antarctica since 1979, driving global sea levels up by more than an inch. Published in Scientific Data, an international polar study reveals that 84 percent of the melt is driven by warming ocean waters eroding glaciers from below.
Satellites Track 12.5 Trillion Tons of Ice Loss Across Decades
Greenland and Antarctica have lost a combined 12.5 trillion tons of ice since 1979, according to a major scientific report published in the journal Scientific Data. The melted ice transformed into nearly 3 quadrillion gallons of water, raising global sea levels by more than an inch since 1979.
An international collaboration of polar scientists, headed by the European Space Agency, integrated data from 27 satellite missions and 45 independent surveys. By combining European satellite observations with NASA satellites, the researchers charted ice volumes in Antarctica back to 1979 and in Greenland back to 1972.
The findings indicate that ice sheets remained relatively stable through the 1970s, 1980s, and into the 1990s. Melt accelerated sharply during the 2010s, with losses climbing steeply across both polar regions.
Warmer Ocean Waters Drive Five-Sixths of the Melt
Five-sixths of the total ice loss does not stem from hotter air at the surface, but from warmer seawater eating away at the ice sheets from below and the sides. Around 84 percent of the combined loss was driven by glaciers speeding up and discharging more ice directly into the ocean, while surface processes account for the remaining 16 percent.
“By reaching back to the 1970s, we can now see how the ice sheets have changed across half a century. More than four–fifths of the ice lost was discharged into the ocean by faster–flowing glaciers, rather than melted at the surface — which tells us the long–term trend is being driven by the dynamic response of the ice sheets to a warming ocean.”
Dr. Inès Otosaka, Northumbria University
In Greenland, the Jakobshavn glacier is retreating by up to 164 feet a day. Meanwhile, retreat rates can reach up to 50 meters daily.
Decadal Acceleration and the 2020 to 2023 Hiatus
Greenland saw its annual rate of ice loss rise from around 60 billion tons in the 1980s to 264 billion tons in the 2010s. Antarctica experienced an increase from roughly 48 billion tons a year in the 1980s to 202 billion tons in the 2010s.
The study observed a temporary slowdown in ice loss between 2020 and 2023. Record snowfall over East Antarctica helped offset glacier losses elsewhere, while a run of milder Greenland summers roughly halved its surface melting.
Researchers emphasized that the three-year pause reflected short-term weather variations rather than a reversal of the long-term trend. Additional measurements examined since the study concluded indicate that the accelerating trajectory has resumed.
Millions More People Face Annual Coastal Flooding
The combined ice discharge has pushed global sea levels up by more than 1.1 inches (3cm) since 1976. Globally, average sea level has risen by 0.14 inches per year since 1999, totaling 3.6 inches over the last 26 years. About 30 percent of that increase stems from oceans expanding as they warm, while 70 percent comes from melting glaciers and ice sheets.
Small changes in sea level carry substantial human consequences. For every third of an inch (one centimeter) of sea level rise, an estimated 2 million to 3 million more people face coastal flooding at least once a year. Professor Andrew Shepherd noted that three centimeters of sea level rise puts another six to nine million people at risk of coastal flooding and erosion.
Next Steps in Satellite Monitoring and Climate Projections
Researchers stress that ice sheets remain the single largest source of uncertainty in future sea level projections. Scientists continue to monitor dynamic processes prone to triggering runaway tipping points.
Sustaining orbital observation programs, including missions such as CryoSat-2 and the Sentinels, remains critical for evaluating climate models and protecting vulnerable coastal communities in the decades ahead.