Antarctica's Recent Mass Gain Was a Temporary Anomaly, Study Finds
Between 2021 and 2023, Antarctica appeared to be growing. Heavy snowfall fueled by wetter weather caused parts of the continent to gain mass, leading some to question whether climate change is really causing the ice to melt. However, a new study shows that the precipitation increase was an anomaly related to extra-warm tropical ocean temperatures, not part of a long-term trend.
The results were published Aug. 19 in Nature.
Antarctica has been "shrinking" for decades as warm water melts ice from below and sends large chunks crashing into the ocean. Annual precipitation can't keep up with the rate of melt, causing a net mass loss. However, the snow that fell on East Antarctica, a vast area that contains nearly 80% of Earth's land-bound ice, added mass faster than the ice was melting. Although mass loss continued in West Antarctica, the general trend seemed encouraging.
"In the early 2020s, there was an exceptional amount of snowfall over parts of Antarctica. Because Antarctica is so big, it doesn't take that much extra snow thickness to counter the loss of ice from the edges of the ice sheet, which led to the perception that the loss of ice is slowing down," said co-author Eric Steig, a UW professor of Earth and space sciences.
The question nagging researchers was whether this would continue into the future. To answer it, they needed to trace the origins of the precipitation.
Because warm air can hold more moisture than colder air, higher latitudes could eventually see wetter conditions due to global warming. Scientists recognize that the average amount of moisture in the air will increase as global temperatures rise. Some saw the heavier snowfall as evidence that this expected trend was materializing in Antarctica.
"Warmer conditions favor storms shifting toward the poles, which could offset ice loss through snowfall," said co-author Qinghua Ding, a professor of atmospheric and climate science at UC Santa Barbara.
But the data told a different story. Using a computational method that involves 'tagging' water molecules, the researchers traced the extra precipitation in Antarctica back to a specific source: the tropical warm pool.
The tropical warm pool is a warm patch of ocean in the western Pacific and eastern Indian oceans that makes an outsized contribution to extreme weather. Water temperature there was notably higher than average between 2021 and 2023, triggering changes in atmospheric circulation that directed more moisture toward East Antarctica.
Historical evidence shows that multiyear warming of the warm pool is normal, occurring every few decades or so before reverting to its average temperature. The recent warming, according to the researchers, was part of this natural cycle.
"The connection to global warming from human activity is tenuous," Steig said, "and most likely just part of the natural background variability of the tropical climate system."
The study also highlights the contrasting situation in West Antarctica, where researchers have connected increased carbon dioxide emissions to the climatic conditions accelerating ice loss. This underscores the complex nature of Antarctic ice dynamics, where different regions respond differently to climate forces.
The Antarctic Ice Sheet is the greatest source of uncertainty in long-term sea-level rise projections, according to the researchers. Understanding the interplay between natural variability and human-driven changes is critical for improving those projections.
The study, published in Nature (2026) with DOI: 10.1038/s41586-026-10912-x, includes additional co-authors Yunhe Wang, Xiaofeng Li, Thomas J. Ballinger, Yoshihiro Nakayama, and Dániel Topál. The research was funded by the National Natural Science Foundation of China, the U.S. National Science Foundation, the U.S. National Oceanic and Atmospheric Administration, the U.S. National Aeronautics and Space Administration, JST PRESTO Japan, the Japanese Ministry of Education, Culture, Sports, Science and Technology, and the Hungarian Academy of Sciences.