Antarctica has been losing large quantities of ice for decades. Yet between 2021 and 2023, something surprising happened: the ice sheet gained around 695 billion tonnes of mass within just 22 months. A new study now shows that the trigger lay thousands of kilometres away in the tropical oceans.
The increase was particularly pronounced in East Antarctica, especially in Queen Mary Land and Wilkes Land. Exceptionally heavy snowfall occurred there over an extended period. The additional snowfall was so substantial that, at times, it more than offset the ongoing ice loss in other parts of Antarctica. The 695 billion tonnes represent the largest increase in mass over a comparable period since GRACE satellite measurements began in 2003.
The explanation is provided by the original study by Yunhe Wang, Qinghua Ding, Xichen Li and other researchers, which was published on 19 August 2026 in Nature under the title Multiyear tropical warm pool warming drives slowdown in Antarctic mass loss. The international team combined satellite measurements of Earth’s gravity with climate models, atmospheric observations and data from Antarctic ice cores.
The cause lies in the tropics
Between 2021 and 2023, the so-called tropical warm pool in the western Pacific and eastern Indian Ocean warmed unusually strongly and persistently. The high sea temperatures altered atmospheric circulation and triggered a chain of so-called Rossby waves, which extended as far as high southern latitudes.
This resulted in a distinctive pressure pattern over East Antarctica. It transported large amounts of moisture, primarily from the central Indian Ocean, towards Antarctica and caused exceptionally heavy snowfall over Queen Mary Land and Wilkes Land.
However, this does not represent a reversal of the trend. Between 2003 and 2024, the Antarctic ice sheet lost an average of around 140.5 billion tonnes of mass per year. West Antarctica also continues to lose ice, partly due to warm seawater melting the ice shelves from below and accelerating glacial outflow.
According to the researchers, similar multi-year warming events in the tropical Warm Pool occur approximately once a decade. The unusual increase in ice mass is therefore likely to be a temporary phenomenon and does not represent a lasting recovery of the Antarctic ice sheet.
At the same time, the study highlights just how closely interconnected the Earth’s climate system is: Temperature changes in tropical seas can influence, thousands of kilometres away, how much snow falls on Antarctica, and thus even alter the mass balance of the Earth’s largest ice sheet in the short term.
Heiner Kubny, PolarJournal