New satellite data reveals that Earth's two major ice sheets—Greenland and Antarctica—have shed a staggering 12.5 trillion tons of ice since 1979, enough to cover the entire continental United States in 5 feet of frozen water. The findings, published Wednesday in the journal Scientific Data, underscore the accelerating impact of climate change on polar regions and the mounting threat to coastal communities worldwide.
While warmer air temperatures play a role, the study's authors emphasize that a surprising five-sixths of the ice loss comes not from atmospheric heat but from warmer ocean waters gnawing at the ice sheets from below and at their edges, causing glaciers to flow faster into the sea. This dynamic process, known as oceanic-driven melting, is a key driver of the rapid disintegration observed in recent decades.
“The ice sheets are melting away fast,” said Eric Rignot, co-author and ice scientist at the University of California, Irvine. “We are melting the polar regions, sea level is rising worldwide and will exacerbate the vulnerability of coastal regions.”
The sheer volume of meltwater—nearly 3 quadrillion gallons—has pushed global sea levels up by about an inch since 1979, on top of other climate-induced factors. While an inch may seem modest, lead author Ines Otosaka of Northumbria University explained that for every third of an inch of sea level rise, an additional 2 to 3 million people face at least one flood event annually. She noted that Greenland's Jakobshavn glacier is now retreating up to 164 feet per day, a stark illustration of the pace of change.
The international team, led by the European Space Agency, combined data from 27 satellites and 45 independent surveys to extend records back to 1979 for Antarctica and 1972 for Greenland. Previous analyses had only gone back to the 1990s. The expanded timeline reveals a clear pattern: ice sheets were relatively stable through the 1980s and early 1990s, but melt began accelerating sharply in the 2010s.
“There is a clear trend that the ice sheets are losing more mass and it has been increasing from decade to decade, especially if you look at the ice being discharged to the ocean,” Otosaka said. “And that’s quite clear that there’s a link to climate change.”
The acceleration paused between 2020 and 2023, but the authors attribute this to short-term weather variability, not a reversal of long-term trends. East Antarctica experienced record snowfall, temporarily offsetting losses from the unstable West Antarctic Ice Sheet. However, Rignot dismissed the hiatus as “just a bump in the record,” insisting that “the long rise is climate and the threat is crystal clear.”
Andrew Shepherd, co-author from Northumbria, warned that the ice sheets are tracking decades behind global warming, meaning continued losses are inevitable even if emissions are halted. “That’s something to be concerned about as it shows that the changes are tracking decades behind global warming, which means we can expect them to continue for decades more,” he said.
Scientists are particularly worried about the potential for runaway collapse. Otosaka noted that dynamic processes—abrupt and active—are more likely to trigger “tipping points” than gradual melting. New York University ice scientist David Holland, who was not part of the study, echoed this concern: “Because most of the ice loss is dynamical and that is exactly what you would expect in an ice sheet instability collapse scenario.”
University of Colorado ice scientist Ted Scambos, also unaffiliated with the research, framed the findings as a stark challenge: “The ‘wild cards’ of Antarctic mass loss continue to pose a challenge for human management of the planet—a clear and present danger, but many decades in the future. We are now as a society smart enough to know the future, but not prudent enough to act upon the knowledge.”
