Why Antarctica's Snowfall Stopped Rising While the Planet Warmed
About 2,000 billion metric tons of snow settle on the Antarctic ice sheet in an average year, and nothing else adds to it. Everything else that happens to the ice sheet takes mass away. So when the snow piles up a little faster, as it did through the last century, water that would otherwise be in the ocean is parked on the continent instead, and the sea rises more slowly than it would have.
Ice cores put that effect at roughly 10 to 11 mm of sea level rise held back over the last century. Then the increase stopped increasing. Across the most recent 40 years, the stretch in which Antarctica has been watched most closely and the planet has warmed fastest, the continent-wide rate at which snow builds up has shown almost no trend. The snow still falls, and the early 2020s include some of the heaviest years on record. What flattened is the rise in that rate, and it is not what physics leads you to expect: warmer air carries more moisture, so a warming world ought to be snowing harder on Antarctica.
A study published on October 2, 2026 in Earth System Dynamics takes that gap between expectation and observation as its subject. David P. Schneider works at the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder. He and colleagues in Copenhagen, Seattle and Delft set a hierarchy of Earth system model experiments against reconstructions of the continent's past surface climate, built from ice cores and other natural records.
The piling up matters because of what it offsets. Antarctica is not gaining ice: the ice sheet has been losing mass for at least four decades, mostly because warm water thinning its floating shelves from below lets the glaciers behind them discharge faster into the sea. Against that, a few millimeters of sea level stored as snow is a partial offset, not a reversal.
The authors ran the model with one influence switched on at a time. With rising greenhouse gases alone, it holds back twice as much sea level over the century as the reconstruction shows. Aerosol pollution, which cools, offsets part of that excess. Greenhouse gases are the underlying driver of the extra snow, and the climate's own swings cannot produce it by themselves.
The winds matter in a different way again: they move the snow around rather than change how much of it falls. More lands on the Antarctic Peninsula and on slopes that face into the wind, and less on the ground lying in their lee. The paper argues that to pull the continent-wide rate down, winds have to be accompanied by a cooler ocean surface.
The authors propose two things that have been holding that temperature down. The westerly winds that circle the continent have strengthened, a trend usually put down to the loss of ozone high in the atmosphere, with greenhouse gases contributing as well. The low-pressure system over the Amundsen Sea has deepened along with them. And since the middle of the last century, meltwater from thinning West Antarctic ice shelves has been freshening the ocean surface. Winds and meltwater both dampen warming at the Southern Ocean surface, and a cooler surface sends less moisture inland to fall as snow.
In the paper's own words, the data "support a hypothesis that high-latitude winds have been working together with ice-shelf meltwater fluxes to dampen Southern Ocean surface warming," and "it has yet to be demonstrated that reduced Southern Ocean warming lowers the Antarctic accumulation rate." The model has no ice shelves that interact with the ocean, so the meltwater is not in it at all. Its effect has to be inferred from separate experiments, and from how closely the runs track the reconstructions.
One model carries all of it, and that model responds to carbon dioxide more strongly than observations support. An earlier study found it piles snow onto Antarctica faster than the real continent has managed. The paper names the single model as its main limitation and asks for the same analysis across several.
The journal made the paper a Highlight, and in a statement on the article page its editors write that the findings "confirm an anthropogenic increase in Antarctic snowfall." That is a firmer verb than the authors use of their own central proposal. The figure underneath the whole comparison is unsettled too. Medley and Thomas built the reconstruction from a database of ice cores and put the effect at about 10 mm since 1901. Another reconstruction of much the same cores reaches about 14 mm, and the spread traces back to how few cores come from the high plateau of East Antarctica.
For the decades ahead, the authors take the low end of the model's range, to allow for the meltwater it leaves out, and put snowfall's contribution at about 0.5 mm of sea level held back per year over the first half of this century. That is less than the widely used version of the same model projects, and less than the ice sheets are currently adding to the sea.
The offset is temporary by design, too. Over decades to centuries, extra mass on the ice sheet pushes harder on the glaciers draining it and speeds their flow into the ocean. More warming brings more melting and runoff at the surface, and eventually rain where snow used to fall. The paper's closing suggestion is a benchmark: whether a model can reproduce a century of Antarctic snowfall should be a test it passes before anyone leans on its picture of the Southern Ocean. The code behind the figures is posted publicly and the model data sit in open archives, so other groups can run that test.