Across the globe, wildfire size and intensity has grown precipitously; a trend observed by many reports from organizations like the World Resources Institute and the United Nations. The expanding impact of fires has followed a similar trajectory within Idaho.
In 2022, the state saw 418,751 acres burned during 355 incidents, according to the Idaho Department of Environmental Quality, nearly 20,000 more than in 2020.
“This is a clear effect of human-caused climate change,” confirmed Dr. Jen Pierce, Associate Professor in the Department of Geosciences at Boise State University and director of the Earth, Wind and Fire Laboratory. “The types of fires that are on everyone’s mind — high-severity, extreme fires that we’ve experienced throughout the Western U.S. — they are climate-driven fires.”
To conceptualize the full extent of fires’ changes on the landscape, she said, it’s critical to understand that Idaho experiences fire in three main ecosystems: high-elevation, middle elevation, and rangeland.
Wildfires burning at higher elevations are a clear indicator of climate change’s impact: a result of “warmer, drier conditions in forests that had previously been too wet and cold to burn at high severity,” Pierce said.
Lower elevation forests aren’t immune. “Middle elevations with drier forests, typically ponderosa pine mixed with Douglas fir, also happen to be where a lot of our communities are located. These forests are complicated; there is both the impact of a warmer, drier climate, which drives severity and acres burned, but these forests also are affected by fuel density, which can be exacerbated by prior fire suppression.” The result? A tinderbox.
Idaho’s plains have experienced similar trends. “We’ve seen a very large increase in fire behavior on rangelands, specifically an increase in fire size, largely driven by an invasive species called cheatgrass.” An easily flammable grass, the plants are exceptionally susceptible to fire in warm, dry conditions, Pierce said.
Another critical impact of climate change? More lighting, said Pierce. Warmer temperatures carry a “statistical increase in likelihood of lightning from convective storms.” In 2022, the Idaho DEQ determined that 145 of the season’s fires were sparked by lighting, but a troubling 192 were caused by humans.
While civilians can’t control the larger issues of fuel density or weather on a day-to-day basis, Pierce said, reducing accidental fires is within everyone’s reach. “83% percent of fires across the country are caused by humans. What do we do? It’s simple: Don’t start fires in the first place.”