With climate change altering their frequency and intensity, atmospheric rivers may become a defining factor in Antarctica’s future.
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For a place renowned as the world’s coldest desert, Antarctica receives an unexpected amount of moisture from a surprising source: atmospheric rivers (ARs). These “rivers in the sky” are long, narrow bands of air carrying enormous amounts of moisture from warmer regions to the poles. While they can deposit heavy snowfall that contributes to the ice sheet’s mass, they can also drive destructive melting, destabilizing glaciers and ice shelves.
Atmospheric rivers are a crucial part of the global water cycle. Stretching more than 2,000 kilometers in length, these invisible streams of vapor transport moisture across continents and oceans. When they reach Antarctica, the interaction between warm, moist air and the continent’s cold, dry atmosphere produces dramatic weather events.
Despite their rarity — occurring only about three days per year at any given location — atmospheric rivers account for an outsized share of extreme weather in Antarctica. Since the 1980s, they have been responsible for 50 to 70 percent of extreme snowfall events in East Antarctica, temporarily bolstering the ice sheet. However, their impact is not always positive. The same warm, moisture-laden air that brings snow can also raise temperatures above freezing, triggering surface melt on ice shelves and weakening their structural integrity.
In the past, atmospheric rivers have played a key role in some of the most dramatic collapses of Antarctic ice shelves. The Larsen A and Larsen B ice shelves, which disintegrated in 1995 and 2002, respectively, were subjected to repeated atmospheric river events that delivered warm air and moisture, leading to extensive melting. These collapses were not isolated incidents—scientists now recognize that AR-driven melting has been a critical factor in ice shelf instability.
One of the most striking recent examples occurred in March 2022, when an extreme atmospheric river event pushed temperatures in East Antarctica 30–40°C above normal. In what has been called the most significant heatwave ever recorded on the continent, temperatures at Concordia Station, near the South Pole, reached an unprecedented −9.4°C—far higher than the usual −50°C expected during that time of year. This event not only triggered widespread surface melting but also contributed to the final collapse of the Conger Ice Shelf, a structure the size of New York City.
“Atmospheric rivers are a double-edged sword for Antarctica. They bring vital snowfall, but they also drive extreme melting and ice shelf collapse. Understanding how they will change in a warming climate is key to predicting future sea level rise”
— Dr. Diana Francis, Khalifa University.
As the climate warms, atmospheric rivers are expected to become more intense, carrying larger amounts of moisture due to increased evaporation from warming oceans. This could have complex effects on Antarctica. On one hand, stronger ARs could bring more snowfall, temporarily increasing the ice sheet’s mass. But on the other, they could also drive more frequent and widespread melting, particularly along the edges of the continent where ice shelves act as barriers holding back glaciers.
The concern is that an increase in AR-driven melting could push Antarctic ice shelves toward further collapse. Once an ice shelf is lost, glaciers behind it can flow more freely into the ocean, contributing directly to sea level rise. While the precise balance of snowfall and melting remains uncertain, scientists agree that atmospheric rivers will play an increasingly important role in determining the future of the Antarctic ice sheet.
Studying atmospheric rivers in Antarctica is challenging due to the continent’s harsh conditions and remote location. Researchers rely on satellite data, weather models, and occasional field expeditions to track AR events and measure their effects on the ice sheet. Climate models suggest that atmospheric river activity will continue to intensify throughout the 21st century, but better forecasts and more detailed observations are needed to predict their long-term impact.
Understanding atmospheric rivers is not just an academic exercise — it is crucial for projecting future sea level rise. Antarctica holds enough ice to raise global sea levels by nearly 60 meters, and even small changes in its stability could have far-reaching consequences for coastal communities worldwide. By improving our knowledge of these powerful weather systems, we hope to refine sea level rise predictions and provide better guidance for policymakers preparing for a changing world.
In collaboration with several scientists from different global institutions, we published a review paper in Nature Reviews on atmospheric rivers in Antarctica. You can read it here.
Jade Sterling
Science Writer
