East Antarctica piled on a record 695 billion tons of ice between 2021 and 2023, a sudden reversal of the continent's long-term melting trend. The cause, researchers say, was not local cold but a patch of unusually warm water in the tropical ocean thousands of miles away.
A tropical nudge that crossed the planet
Scientists led by the Institute of Oceanology of the Chinese Academy of Sciences published the finding in Nature on August 19. They used gravity satellite data, ice core records, and atmospheric simulations to trace the extra snow back to its source.
The tropical warm pool, where the western Pacific meets the eastern Indian Ocean, stayed unusually hot during those years. That warmth set off a Rossby wave train, a chain of atmospheric waves that can carry weather signals across vast distances. The waves reached the high southern latitudes and helped reorganize air circulation around Antarctica.
Snow delivery via atmospheric rivers
The shifting circulation created a pressure pattern with low pressure south of Australia and high pressure along the East Antarctic coast. That setup steered moisture from the midlatitude Indian Ocean toward the continent through atmospheric rivers, narrow bands of water vapor that can dump intense snowfall.
Ice cores confirmed the snow accumulated on the ground. The gain was the largest ever recorded by the GRACE satellite missions, which have tracked Antarctic ice changes for two decades.
A temporary pause in a longer decline
Antarctica has lost ice at an average rate of about 140.5 billion tons per year over the past 20 years. The 695 billion ton gain briefly slowed that overall loss, but it did not reverse the continent's long-term contribution to sea level rise.
For local researchers and glaciologists, the event was a striking example of how distant climate signals can reshape Antarctic weather. The study highlights the role of tropical ocean temperatures in driving Antarctic snowfall, a factor that adds complexity to projections of future ice loss and sea level rise.
The episode also shows how natural variability can temporarily mask or amplify human-caused changes. Understanding these connections will be key to predicting how Antarctica will respond as the planet continues to warm.
