Tropical warm pool warming drove record 695-billion-ton Antarctic ice gain in 2021-23

September 7, 2026 at 04:04 AM2 min

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A persistent patch of unusually warm tropical ocean intensified snowfall over East Antarctica, contributing to a temporary net ice sheet mass gain of about 695 billion tons, according to a study published in Nature on August 19. The gain, the largest observed by GRACE satellite missions, temporarily slowed the Antarctic Ice Sheet's overall loss of mass. Researchers led by the Institute of Oceanology of the Chinese Academy of Sciences linked the event to a Rossby wave train triggered by warming in the tropical warm pool during 2021-23.

Key Facts

The Antarctic Ice Sheet gained about 695 billion tons of mass between 2021 and 2023, the largest gain observed by GRACE satellite missions.
The study was published in Nature on August 19 by researchers led by the Institute of Oceanology of the Chinese Academy of Sciences.
Sustained warming in the tropical warm pool during 2021-23 triggered a Rossby wave train that altered atmospheric circulation over East Antarctica.
The resulting pressure pattern strengthened atmospheric rivers that transported water vapor from the midlatitude Indian Ocean toward East Antarctica.
During the past two decades, Antarctica has lost ice at an average rate of approximately 140.5 billion tons per year.

Record Ice Gain

Between 2021 and 2023, the Antarctic Ice Sheet gained about 695 billion tons of mass, making it the largest Antarctic mass gain observed by the GRACE satellite missions. This temporary gain contrasted with the average annual loss of approximately 140.5 billion tons per year over the past two decades. Researchers led by the Institute of Oceanology of the Chinese Academy of Sciences (IOCAS) analyzed gravity satellite measurements, ice core snow accumulation records, and atmospheric circulation simulations to identify the cause.

Tropical Trigger

Sustained warming in the tropical warm pool during 2021-23, a region where the tropical western Pacific meets the eastern Indian Ocean, initiated a Rossby wave train that traveled toward Antarctica. Eddy mean flow feedbacks strengthened and prolonged the resulting circulation pattern, producing a north-south dipole with unusual low pressure south of Australia and unusual high pressure along the East Antarctic coast. This pressure pattern strengthened the transport of water vapor from the midlatitude Indian Ocean toward East Antarctica through atmospheric rivers.

Atmospheric River Impact

Atmospheric rivers are relatively narrow corridors in the atmosphere that can carry enormous amounts of water vapor over long distances. When these moisture corridors reached East Antarctica, the water vapor fell as heavy snow, contributing to the temporary net mass gain.