November 1, 2023
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From stray bullets to power companies, humans cause nearly all of California’s wildfires

Flames consumed several homes as the Caldor Fire advanced toward the Echo Summit area of California on August 30, 2021.
On a sweltering summer day in 2021, a fire suddenly swept through drought-dried brush and leaped into the treetops in California’s Sierra Nevada. A local father and son tasked with starting the 222,000-acre project Fire Heat with their target shooting equipment, are among the thousands of humans accused of setting nearly every wildfire in the state since 2000. In addition to utility executives, whose faulty electrical equipment has contributed to the state larger and deadliest wildfires, the list supposedly includes motorcyclists who remove spark arresters and couples who celebrate anniversaries with sky lanterns. “It’s human recklessness one way or another,” says Craig Thomas, founder of the nonprofit Fire Restoration Group.
California forests are increasingly susceptible to wildfires due to climate change and poor forest management. As for actual ignitions, scientists have been documenting a gradual increase in human participation, but facing the full scope of our responsibility remains daunting. Throughout the state, 95 percent Reportedly, of all forest fires are human-caused. Thomas, along with Brent Skaggs, a retired U.S. Forest Service wildfire management officer, used public Forest Service records to reveal a staggering 19,543 wildfires attributed to humans between 2000 and 2022 on Service lands. Forestry in California. It’s not just about campfires and cigarettes. Careless use of trucks, chainsaws or other equipment causes almost a quarter of fires. Others are caused by illegal fireworks, as well as energy generation, according to agency statistics that Thomas and Skaggs analyzed for American scientist.

Fire is a natural part of most forest ecosystems and has been around much longer than humans. For millennia, lightning caused the vast majority of wildfires, but today it causes only 5 percent of California’s. And man-made fires tend to be more destructive and deadly than those caused by lightning; They often begin near developed land with fewer trees and later in the season when grasses are especially combustible. California wildfires attributed to humans between 2012 and 2018 were on average 6.5 times larger than those caused by lightning and killed three times as many trees. They are also more expensive because they tend to threaten homes, rather than half of the costs of fighting forest fires They come from defending homes.
Understanding the sources of the sparks that start fires (not just the conditions that allow them to spread) could help save lives, homes and ecosystems, says Jennifer Balch, who studies fire ecology at the University of Colorado Boulder. She emphasizes prevention in public messaging and enforcement of laws designed to reduce illegal fire starting. “We are the fire species,” says Balch. “We can do a lot to change its course in the landscape.”
With forests volatile and the climate increasingly erratic, public responsibility is critical. “Don’t do stupid things in the woods,” Thomas says. “These forests cannot tolerate human recklessness.”