A new study in Nature has identified a recurring atmospheric connection between tropical ocean temperatures and snowfall in East Antarctica, giving researchers another mechanism to build into projections of Antarctic ice behavior and future sea-level rise. The finding helps explain an unusual period between July 2021 and April 2023, when the Antarctic Ice Sheet gained approximately 695 gigatons of mass, the largest 22-month increase in the two-decade GRACE satellite record the researchers examined. About 68% of that continent-wide increase occurred in the Queen Mary Land and Wilkes Land region of East Antarctica. The gain temporarily slowed Antarctica's overall mass loss, but the researchers caution that it does not represent a reversal of the continent's longer-term trajectory.
Tropical Warming Changed Antarctic Snowfall
The study links the East Antarctic mass increase to persistent warming in the tropical warm pool, a region of exceptionally warm ocean water centered around the Maritime Continent. Researchers found that the warming helped generate a poleward-moving Rossby wave train, creating a high-pressure anomaly over East Antarctica. That circulation pattern increased the transport of moisture toward Queen Mary Land and Wilkes Land, producing enhanced precipitation and greater ice accumulation. The moisture was primarily transported from the mid-latitude Indian Ocean rather than generated by increased evaporation immediately surrounding Antarctica, and the study's water-tracing analysis indicates that atmospheric circulation changed the pathways through which storms and atmospheric rivers delivered moisture to the continent. Researchers also found evidence that similar multiyear tropical warm pool events occur roughly once per decade, indicating the mechanism is not unique to the 2021-2023 period.
Why the Finding Matters for Sea-Level Models
The Antarctic Ice Sheet remains a major source of uncertainty in long-term sea-level projections because its mass balance reflects several competing processes. West Antarctica has experienced sustained losses driven largely by ocean-related ice melt and glacier discharge, a dynamic already showing up in separate research on hidden channels beneath the ice that can accelerate West Antarctic melt. East Antarctica, by contrast, is more sensitive to variations in snowfall, meaning temporary precipitation increases can offset losses elsewhere without changing the underlying long-term picture. The new research gives modelers another recurring source of natural variability to account for. The authors found that the immediate 2021-2023 precipitation increase was driven primarily by the tropical teleconnection rather than the long-term response to anthropogenic warming. In the Queen Mary Land and Wilkes Land region, modeled precipitation associated with anthropogenic forcing represented only about 9% of the observed precipitation anomaly during the event, a distinction that could matter when interpreting short periods of Antarctic mass gain or slower ice loss.
The researchers conclude that the recent slowdown is probably temporary. West Antarctic losses continued during the period, and vulnerable portions of East Antarctica remain exposed to ocean-driven melting, a risk already factored into how coastal cities are modeling flood exposure against aging infrastructure and rising seas. The researchers also note that the strength of the newly identified tropical connection could itself change as atmospheric moisture, storm tracks, and atmospheric rivers respond to a warming climate. Ultimately, the study reinforces a modeling challenge already visible in broader climate monitoring, showing sea levels rising faster than in earlier decades. Short-term Antarctic changes can differ substantially from the longer-term trend. Better representation of those recurring climate connections could help narrow some of the uncertainty surrounding how quickly Antarctic ice loss translates into future coastal exposure.
