Snow that piles up on streets, shuts down schools and immobilizes communities could be a distant memory in Spokane and Coeur d’Alene by the end of the century.
But wildfire seasons will probably last a month longer by 2100, with catastrophic fires occurring at more frequent intervals. And a drier climate could turn forests in the Northern Rockies into net emitters of carbon dioxide – the key greenhouse gas associated with global warming – instead of carbon sinks.
Scientists at the University of Montana made those predictions while modeling the effect of climate change on the region. They reviewed 50 years of weather records, stream-flow measurements and other data to make climate projections through 2100.
“The overall summary is that winter will be about a month shorter and summer a month longer,” said Steven Running, a UM professor and lead researcher for the report, which was funded by the National Commission on Energy Policy. A synopsis of the report was released Tuesday.
The shifting climate trends will have significant ramifications for the region’s mountain snowpacks, which supply up to 75 percent of the water for stream flows.
“We’re so starved for water that if it gets 20 percent drier over here, it’s going to push us into desert,” Running said.
Running’s work mirrors the University of Washington’s Climate Impacts Group’s research, which also predicts temperature increases, earlier snowmelt and a longer wildfire season as a result of higher atmospheric carbon dioxide concentrations.
But the research comes amid growing public skepticism about global warming. A national poll by the Pew Research Center for People & the Press last fall found that 57 percent of Americans think there is solid evidence that the earth’s average temperature is getting warmer, down from 71 percent in April 2008. An even smaller number – 36 percent – believed that warmer global temperatures are tied to human activity, such as burning fossil fuels.
But while public opinion is backsliding, the science on global warming hasn’t changed, said Running, a member of the United Nation’s Intergovernmental Panel on Climate Change, which won the 2007 Nobel Prize for its work.
“The public attitude has shifted,” he said, “but it’s not based on any science.”
The models predict that the average annual temperature in the Northern Rockies will increase by 3.6 to 7.2 degrees Fahrenheit by the end of the century. Snow accumulations will become rare at low elevations, with winter precipitation falling mostly as rain.
“We won’t have the snow that sticks around,” Running said.
Snow will still pile up in the mountains, but the snowpack will melt earlier, he said. Spring runoff already occurs about two weeks earlier than it did 50 years ago. By the end of the century, that will accelerate by another four to six weeks, Running said.
Without the late snow cover, wildfires are burning into forests at higher elevations. In addition, milder temperatures are fueling increased insect epidemics, leaving more tinder-ready trees. And by 2100, climate changes will delay autumn rains by six to eight weeks, creating a longer fire season.
Those are troubling predictors for a wildfire season that already burns hotter and longer, Running said. The forested area that burned in the West from 1987 to 2005 is six times greater than the acreage that burned during the previous 16 years.
More than 360,000 people live in the forest or at its edges in the Intermountain West, in homes valued at $21 billion, the report said. An increase in big fires could cause significant property losses and disruption, Running said.