COLUMBUS —Enough science is in to know this much: Montanans will be sweating through hotter days, fighting more wildfires and dealing with increasing uncertainties in agriculture through the decades ahead.
“There’s 100 percent model agreement that we’re going to get warmer,” said Cathy Whitlock, professor of earth sciences at Montana State University in Bozeman. “Models are always getting improved. They are projections with a lot of uncertainties. But the models all agree on the trend.”
Whitlock, a lead scientist on the Montana Climate Assessment, presented the report’s findings during talks in both Red Lodge and Columbus this week. In Columbus, Whitlock spoke to about 30 people — a packed house — in the Columbus City Hall Courtroom. The talk was sponsored by Stillwater Rising, a local non-partisan group that encourages community conversations.
Among the researchers’ conclusions, Whitlock told the Columbus group: late-season irrigation will suffer, cheatgrass will thrive and extreme weather events will become more frequent.
While temperature trends are clear, data suggest that annual moisture levels will vary little. What will vary is the timing of that moisture. Fall through spring periods are expected to be wetter, while farmers will probably be scratching for moisture during the late-summer growing season.
The assessment specifically focused on Montana’s agriculture, water and forests. Unlike most climate studies, Montana’s assessment involved input from a broad swath of citizens. The authors then used that input to craft a website — montanaclimate.org — that’s useable, updateable and sustainable.
“Most state assessments don’t spend the time talking to stakeholders,” Whitlock said. “In the end, we always wanted to give something back to the state.”
Whitlock and her group studied pollen and charcoal to determine past fluctuations in climate and project trends into the future.
It’s been 3 million years since the earth’s carbon dioxide level rivaled today’s, she said. At that time the sea level was 25 meters higher and Montana’s climate more closely resembled that of present-day South Carolina. Today’s trends differ, too, from the last warming period that took place 6,000 to 9,000 years ago. Back then, she said, both seasons weren’t warmer as they are now.
“We’re really in uncharted territory,” she said.
Whitlock listed examples of measurable changes that have already impacted the Big Sky state. Between 1950 and 2015, the growing season lengthened by 12 days. Between 1948 and 2002, peak runoff shifted earlier by two weeks. Since 1950, Montana’s average temperature has climbed by 3 degrees Fahrenheit.
Using charts and graphs, the report synthesizes the data into two possible projections: the “stabilization” scenario, based on best practices for reducing climate change, and the “business as usual” model, based on proceeding with no attempt to reduce carbon dioxide emissions. In the first scenario, the temperature is expected to rise another 4.5 degrees by 2050 and 5.6 degrees by 2100. In the second scenario, Montana is forecast to see increases of 6 degrees and 9.8 degrees respectively.
“Montana is warming and it’s warming faster than the U.S. average,” Whitlock said.
Rising temperatures will result in both plusses and minuses. And many unknowns.
The longer growing season will make possible more crop diversity, but heat stress on crops and livestock will take its toll. Likewise, some tree species will thrive in warmer temperatures, but so too might pests like pine bark beetle.
There is one clear downside. Montana’s prolonged fire seasons — since the 1970s the fire season has stretched from five to seven months — are not only expected to increase the risk of fire but the size, frequency and severity of those fires. Thinning trees around homes in the wildland-urban interface and target treatments for forests in dry areas may offer the best bang for the buck, Whitlock added.
Whitlock believes solutions will be found in efficiencies, technology and by reducing our reliance on fossil fuels.
“Montana didn’t really cause climate change,” she said. “But we will either mitigate or adapt.”
The authors of the assessment hope, in the future, to update the website with information on additional sectors that are and will be impacted by climate change in Montana.