The Impact of Atmospheric Rivers on Greenland’s Ice Sheet

Greenland’s ice sheet is the second-largest ice cap on Earth, and due to the planet’s rising temperatures, it is experiencing significant melting. Human-induced climate change is intensifying atmospheric rivers, but recent research suggests that their impact on Greenland’s ice sheet is more complex than previously thought.

A research team has investigated the recent impact of an intense atmospheric river on Greenland’s ice sheet. Unexpectedly, they found that this phenomenon deposited 16 billion tons of snow on Greenland, enough to temporarily slow its ice melt. As detailed in a study published on March 3 in the journal Geophysical Research Letters, atmospheric rivers might have a more positive impact than researchers had theorized.

"I was surprised by just how much snow was dumped on the ice sheet over such a short period… but it’s a gobsmacking contribution to Greenland’s annual ice mass."

"I was surprised by just how much snow was dumped on the ice sheet over such a short period," Alun Hubbard, a glaciologist at the Arctic University of Tromsø and study co-author, said in an American Geophysical Union (AGU) statement. "I thought it’d be a minute amount, but it’s a gobsmacking contribution to Greenland’s annual ice mass."

Global Warming and Ice Sheet Melting

Global warming is melting Greenland’s ice sheets at unprecedented rates. In 2023, the ice sheet lost 80 gigatons of water — that’s approximately 660,430 gallons (2.5 million liters) of water per second. In 2024, it shrank for the 28th year in a row. If the entire ice sheet were to melt, the sea level would rise by over 23 feet (7 meters). Climate scientists predict that climate change will also intensify atmospheric rivers, making them stronger and more frequent, which could accelerate ice loss in Greenland.

However, an atmospheric river that occurred in March 2022 challenges this notion. At the time, lead author Hannah Bailey, a geochemist at the University of Oulu, was in Svalbard. As the atmospheric river pummeled the small Norwegian archipelago with intense rain, Bailey wondered what it was doing 1,245 miles (2,000 kilometers) away, in Greenland. A year later, she and Hubbard traveled to southeastern Greenland to investigate the matter.

Investigating the Impact of Atmospheric Rivers

There, the two researchers collected a 49-foot (15-meter) core of firn — dense, compacted snow that gradually turns into glacial ice. Ice cores are nature’s record keepers, and this one documented almost 10 years worth of snow accumulation. By comparing complex analyses of the ice core to local weather data, Bailey and Hubbard identified the ice core section corresponding to the 2022 atmospheric river.

"Using high-elevation firn core sampling and isotopic analysis allowed us to pinpoint the extraordinary snowfall from this atmospheric river," Bailey explained. "It’s a rare opportunity to directly link such an event to Greenland ice sheet surface mass balance and dynamics."

The Findings

The ice core section revealed that the atmospheric river had brought 16 billion tons of snow to Greenland, single-handedly offsetting the ice sheet’s yearly ice loss by 8% in just three days. As stated in the AGU press release:

The atmospheric river had pelted Svalbard with rain, but 2,000 kilometers (1,245 miles) away in southeastern Greenland, it delivered snow — and lots of it. On March 14, 11.6 billion tons of snow fell on the ice sheet, with an additional 4.5 billion tons over the next few days. One gigaton of snow roughly equates to one cubic kilometer of fresh water, which could completely fill the U.S. capitol building more than 2,200 times.

The event also covered the ice sheet with fresh, reflective snow, increasing the region’s albedo (its ability to reflect sunlight) and setting back seasonal ice melt by almost two weeks — despite 2022’s abnormally warm spring temperatures.

Conclusion

"Sadly, the Greenland Ice Sheet won’t be saved by atmospheric rivers," Hubbard said. "But what we see in this new study is that, contrary to prevailing opinions, under the right conditions, atmospheric rivers might not be all bad news." If global temperatures continue to rise, however, atmospheric rivers could one day bring rain instead of snow to Greenland. In fact, Hubbard and Bailey emphasize that more research is needed to understand both the current and future impact of atmospheric rivers on the Northern Hemisphere’s largest ice mass.

"Atmospheric rivers have a double-edged role in shaping Greenland’s — as well as the wider Arctic’s — futures," Bailey concluded.