Antarctica’s ice briefly increased after heavy snowfall: Why scientists remain concerned

Antarctica appeared to defy its long-running pattern of ice loss between 2021 and 2023, when unusually heavy snowfall added enough mass across parts of the continent to sharply slow the overall decline. Scientists now say the increase was real, but temporary. The question is why snowfall became so powerful during this period and whether more snow can actually reverse Antarctica’s broader ice-loss trend. Recent studies point to unusual atmospheric conditions, moisture-rich storms and warming in tropical ocean regions as the main reasons behind the short-lived change.

Rather than indicating that Antarctica had suddenly recovered, the research suggests that a period of exceptional accumulation briefly outweighed continuing losses from glaciers and ice discharge. A separate Nature Geoscience study has found that the Antarctic Ice Sheet is still very likely to lose mass during this century, even under aggressive emissions-reduction scenarios.

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How did heavy snowfall make Antarctica gain ice?

The unusual episode was concentrated largely in East Antarctica. Research published in Nature found that persistent warming in a tropical region of the Indian and Pacific oceans, known as the tropical warm pool, helped set off a chain of atmospheric changes that eventually increased snowfall over parts of East Antarctica.

The warmer tropical waters generated a sequence of atmospheric pressure patterns that travelled towards the Antarctic. This produced a high-pressure anomaly over parts of East Antarctica, strengthening the transport of moisture towards the continent and increasing precipitation. Much of the moisture involved in the event was traced to the mid-latitude Indian Ocean.

The result was a dramatic increase in surface accumulation over areas including Queen Mary Land and Wilkes Land. The Nature study found that the Antarctic Ice Sheet gained roughly 695 gigatonnes of mass between July 2021 and April 2023 compared with the starting point in July 2021. The increase was large enough to offset ice losses elsewhere and bring the continent’s overall mass balance close to zero during the period.

Atmospheric rivers added more snow

Another study published in Communications Earth & Environment identified a second important part of the explanation. Atmospheric rivers, which are narrow corridors carrying large quantities of water vapour, became more frequent and intense around Antarctica after 2020.

These moisture-rich systems delivered additional precipitation to several regions, including the Antarctic Peninsula, Queen Maud Land and Wilkes Land. Stronger westerly winds and reduced sea-ice cover also contributed to the recent increase in surface accumulation.

The researchers concluded that the extra snowfall was sufficient to counterbalance continued ice discharge from outlet glaciers. In other words, Antarctica was not losing less ice because its glaciers had stopped releasing ice. Instead, the continent was receiving an unusually large amount of new snow at its surface.

Why snowfall cannot permanently solve Antarctica’s ice-loss problem

Snowfall adds mass to the top of the ice sheet, but glaciers continue moving towards the ocean. Ice can be lost through glacier discharge, calving and melting, particularly where contact with relatively warm ocean water affects ice shelves and grounded ice.

That distinction is crucial. A period of unusually high snowfall can temporarily improve the ice sheet’s mass balance without stopping the processes that drive long-term losses.

The researchers behind the Nature study found that the atmospheric pattern responsible for the recent gain is not a permanent feature. Similar warming episodes in the tropical warm pool occur roughly once a decade, meaning the circulation pattern that produced the exceptional snowfall is expected to fade rather than become a persistent source of Antarctic ice accumulation.

This is why scientists describe the recent gain as a temporary interruption rather than a recovery. Nature’s analysis of the research noted that the Antarctic Ice Sheet is likely to return to losing mass as this unusual atmospheric influence weakens.

What does the latest research say about Antarctica’s future?

The longer-term outlook remains concerning. A Nature Geoscience study published in 2026 used observations and climate and ice-sheet modelling to estimate how the Antarctic Ice Sheet could evolve under different emissions scenarios.

The research found at least a 92% probability that Antarctica is committed to losing mass during the 21st century even under an aggressive emissions-reduction scenario. Under a very high-emissions pathway, the study estimated that Antarctic ice loss could contribute up to 25.4 centimetres of global mean sea-level rise by 2100 at the 95th percentile, with a median estimate of 15.7 centimetres. These are modelled projections rather than predictions of a fixed outcome.

The study also concluded that warming-driven increases in snowfall are very unlikely to compensate for ocean-driven ice loss over the long term. That means more precipitation can provide a temporary boost to Antarctica’s mass balance, but it does not necessarily change the continent’s broader trajectory.

Antarctic sea ice tells a separate story

The recent snowfall should also not be confused with the condition of Antarctic sea ice. Sea ice forms from ocean water, while the Antarctic Ice Sheet is land-based. Losing sea ice does not directly raise global sea levels in the same way that losing land ice does, although changes in sea ice can influence the wider Antarctic climate system and the conditions surrounding ice shelves.

In September 2026, Antarctic sea ice reached a winter maximum of about 17.59 million square kilometres, making it the third-lowest maximum in the satellite record if the date and value are retained in the final assessment. The four most recent years have also produced exceptionally low Antarctic sea-ice values, underlining the contrast between the temporary gain in ice-sheet mass and the continent’s broader changing frozen environment.

Can heavy snowfall reverse Antarctica’s condition?

The recent episode shows that snowfall can make an enormous difference to Antarctica’s short-term mass balance. When moisture-laden weather systems bring exceptional amounts of snow, the added surface accumulation can temporarily outweigh ice being lost through glaciers and other processes.

But the evidence does not support the idea that heavy snowfall has permanently reversed Antarctica’s decline. The atmospheric setup behind the 2021 to 2023 gain was unusual and temporary, while the underlying processes driving long-term ice loss continue.

So, the snowfall mattered, but it was more of a pause in Antarctica’s wider ice-loss story than a turning point. The continent briefly gained enough mass to surprise scientists, yet the latest evidence indicates that sustained warming and ocean-driven ice loss remain the dominant long-term concern.