A new international study shows that Antarctica's ice sheet gained 695 billion metric tonnes of mass between 2021 and 2023, slowing down its long-term ice loss against the backdrop of climate warming.
Researchers from China, the United States, Hungary and Japan found that the ice gain was the largest recorded in nearly two decades of satellite observations. They believe an atmospheric phenomenon thousands of kilometers away drove the gain, with warm tropical oceans promoting heavy snowfall on the world's southernmost continent and counterbalancing ice lost to melting.
The Antarctic ice sheet is one of the main sources of uncertainty for global sea level rise. Between 2003 and 2024, the continent lost about 140.5 billion metric tonnes of ice per year on average.
First author Wang Yunhe, an associate researcher at the Institute of Oceanology under the Chinese Academy of Sciences, said the unusual ice gain was driven by warming in the tropical western Pacific Warm Pool, one of the world's warmest ocean regions and one of the strongest sources of heat release to the atmosphere. From 2021 to 2023, sea temperatures in the region warmed unusually and persistently, ultimately reshaping atmospheric circulation.
Water vapor from the mid-latitude Indian Ocean was transported to East Antarctica, bringing heavy snowfall there and causing the ice sheet mass to increase, according to Wang.
However, the study, published in the journal Nature on Aug 19, noted that similar warming events occur roughly once a decade, suggesting the ice gain is temporary and cannot reverse the long-term trend of ice loss.
West Antarctica continues to lose ice, and ocean warming threatens some outlet glaciers in East Antarctica by melting ice shelves from beneath and accelerating ice flow, Wang added.
In a companion commentary also published in Nature, Jonathan Wille, a researcher at the French National Center for Scientific Research, wrote that researchers must account for tropical climate variability to understand Antarctica's future and that of the rest of the planet.
Antarctic ice sheet sees temporary mass gain: study
