Mountain snow is on the decline across the western US, and climate change is largely to blame, according to a new study, reports Buzzfeed.
Scientists measured snowpack at nearly 700 sites spread across western mountain ranges over six decades, 1955 to 2016, and carried out many computer simulations of snowpack levels over time. Both the observations and modeling showed widespread declines in snowpack, according to the results published this month in Climate and Atmospheric Science.
This new work follows a similar 2005 study by the same team showing snowpack declines out west, but to a lesser extent.
“In other words, it’s getting worse,” Philip Mote, a professor of oceanic and atmospheric physics at Oregon State University and the lead author of both studies, told BuzzFeed News. “It’s pretty robustly caused by rising temperatures.”
Some of the largest declines were in eastern Oregon and northern Nevada, as well as specific spots in California, Montana, Washington, Idaho, and Arizona, according to the study. But in a few locations, Big South in northern Colorado and Siskiyou Summit in western Oregon for example, snowpack has actually increased.
The researchers decided to use observations starting in 1955 because that’s when measurements started being more widely available compared to previous years. But this start date, similar to the 2005 study’s 1950 start date, has been criticized. That’s because it falls in the middle of an especially snowy period for the Pacific Northwest and Colorado, suggesting the observed declines are exaggerated compared to what they would be if the researchers had included earlier years.
“This seems more like a political paper than a scientific paper,” Cliff Mass, an atmospheric sciences professor at the University of Washington who was not involved in the study, told BuzzFeed News. If you start using observations from the 1950s, which were especially cold and snowy, he said, “that’s hyping up” the trend.
They also used the models to look for a possible climate change signal, by running simulations with observed global warming and others without it. The results showed that if we didn’t have the warming, Mote said, “it would have been essentially no change.”
“We have every reason to think the long-term trend will continue into the future because of man-made climate change,” said scientist David Pierce, who works at the University of California, San Diego’s Scripps Institution of Oceanography. What’s more, he said, the research “shows us climate change is affecting us now.”