About 12.5 trillion tons of ice from glaciers in Greenland and Antarctica have melted since 1979, creating enough water to stack ice 5 feet deep across the continental United States, according to a scientific report published Wednesday in the journal Scientific Data. The international collaboration of polar scientists, headed by the European Space Agency, found that five-sixths of this melt comes from warmer waters eating away at ice sheets from below and the sides, driving sea levels up by about an inch globally.
Melting Ice Sheets Push Global Sea Level Rise
The vast volume of melted ice turned into nearly 3 quadrillion gallons of water, adding an inch to global sea levels since 1979 alongside other climate factors, according to the report. Lead study author Ines Otosaka, an ice scientist at Northumbria University in England, noted that for every third of an inch of sea level rise, another 2 to 3 million people face flooding at least once a year.
Did you know? The Jakobshavn glacier in Greenland is now retreating up to 164 feet a day, according to study author Ines Otosaka.
Researchers charted ice sheet volumes in Antarctica back to 1979 and in Greenland back to 1972 by incorporating NASA satellites alongside European Space Agency data. The international team used 45 independent surveys and 27 different satellites to compile the findings. David Holland, a New York University ice scientist who was not part of the study, said that the use of relatively independent methods gives him greater confidence in the result, confirming the upward trend is real.
Dynamic Processes Trigger Runaway Tipping Points
The biggest changes observed by scientists involve dynamic processes, which are more abrupt and active than the slow steady melting from warm air. According to Ines Otosaka, these active shifts are prone to trigger runaway tipping points in polar regions.
“Most of the ice loss is dynamical and that is exactly what you would expect in an ice sheet instability collapse scenario,” said David Holland. The study showed that ice sheets remained relatively stable through the 1970s, 1980s, and into the 1990s before melt started happening and rapidly escalated during the 2010s.
Andrew Shepherd, a study co-author also of Northumbria University, explained that these changes track decades behind global warming. That lag means melting will likely continue for decades even if humanity successfully stops heating the planet.
Antarctic Stability Offset by East Antarctica Snowfall
While the West Antarctic Ice Sheet experienced rapid melting, overall stability in parts of Antarctica was maintained because East Antarctica recorded heavy snowfall that compensated for the losses, according to the study’s authors. An apparent pause in accelerating melt numbers between 2020 and 2023 reflected short-term weather variations rather than long-term trends, with measurements since 2023 showing the accelerating trend picking back up.
“The long rise is climate and the threat is crystal clear,” said study co-author Eric Rignot of the University of California, Irvine. Ted Scambos, a University of Colorado ice scientist who was not involved in the research, described Antarctic mass loss as a clear and present danger for the distant future, noting that society has enough knowledge to see the future but lacks the prudence to act.
Frequently Asked Questions
How much ice has melted from Greenland and Antarctica since 1979?
About 12.5 trillion tons of ice have melted from glaciers in Greenland and Antarctica since 1979, turning into nearly 3 quadrillion gallons of water, according to a report published in Scientific Data.
What is causing the majority of the ice sheet melt?
Five-sixths of the melt is driven by warmer waters eating away at the ice sheets from below and the sides, causing glaciers to flow into the oceans, rather than coming solely from hotter air.
How much has global sea level risen from this ice melt?
The meltwater has pushed global sea levels up by about an inch since 1979, contributing to coastal vulnerability worldwide.
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