Climate Change Is Reducing Snowpack, Study Finds

In the past 40 years, snowpack has sharply declined and is expected to continue this trend, according to a new study by researchers from Dartmouth College.

With winter storms currently hitting across the U.S., snow can be a confusing element when it comes to better understanding and tracking climate change and global warming. Some areas in recent years are observing clear declines in snowfall, with fewer snow days for schools in the Northeast, while other places, like California in early 2023, have seen heavy snowfall after extended snow droughts.

The new study, published in the journal Nature, provides evidence that the Northern Hemisphere is seeing a trend in rising snow loss, particularly for March from 1981 to 2020. The authors noted that human-caused climate change is at least in part to blame. 

Researchers Alexander Gottlieb, a Ph.D. candidate at Dartmouth College, and Justin Mankin, associate professor at Dartmouth College’s Department of Geography, used snowpack reconstructions for the Northern Hemisphere and extensive climate modeling to track trends over the past 40 years. 

Out of 169 major river basins in the Northern Hemisphere, Gottlieb and Mankin identified “robust snow trends” in 82 of them, and 31 of these they were able to confidently attribute to human-caused climate change, the study said. Seventy of the major river basins showed significant declines in snowpack over the 40 years, while 12 showed an increase in snowpack, The Associated Press reported. Parts of Alaska, Canada and Central Asia have experienced increased snowpacks.

For areas with decreasing snowpack, the researchers found that river basins in the southwestern U.S. and western, central and northern Europe were experiencing the greatest declines since the 1980s, with a 10% to 20% decline per decade.

“The train has left the station for regions such as the Southwestern and Northeastern United States,” Gottlieb said in a statement. “By the end of the 21st century, we expect these places to be close to snow-free by the end of March. We’re on that path and not particularly well adapted when it comes to water scarcity.”

The researchers are concerned about how significant snowpack loss could affect watersheds and water scarcity. Snow loss can increase when it hits what Gottlieb and Mankin described as the “snow-loss cliff,” when temperatures rise about 17 degrees Fahrenheit. After this point, snow loss rapidly increases even with minor rises in temperature, CNN reported.

Many communities rely on snow pack to provide more water in the watershed, for which these communities get their water supply. These losses are expected to increase moving forward, and Mankin warned that it’s time to start preparing for permanent changes to adapt to this decline source of water now.

“Once a basin has fallen off that cliff, it’s no longer about managing a short-term emergency until the next big snow,” Mankin said, as reported by Dartmouth College. “Instead, they will be adapting to permanent changes to water availability.”