Dr. Park, like other experts interviewed, noted that California’s engineered landscapes are not the only factor behind its high-impact disasters. The state’s size and geographic diversity expose it to an unusually wide range of extreme climate events. And its large population means that when disasters do strike, they are very likely to affect large numbers of people.
Still, the manufactured systems that support the state’s population and economy have left the state especially vulnerable. The wildfires are only the latest example of how climate change can cause engineered landscapes to go awry. Those blazes are partly the result of hotter temperatures and drier conditions, scientists say, which have made it easier for vegetation to ignite, causing fires to become bigger, more intense and more frightening.
“Sometimes you feel really small and helpless,” said Mandy Beatty, who manages and maintains trails through the forests of the Sierra Nevada for the Sierra Buttes Trail Stewardship, a nonprofit group. On a chalkboard in her house in Plumas County, on the edge of the forests, she counts how long she and her husband have endured the smoke. Friday was Day 33. The fire, still raging, is on the other side of the mountain.
The intensity of the fires also reflects decades of policy decisions that altered those forests, according to Robert Bonnie, who oversaw the United States Forest Service under President Barack Obama. And the cost of those decisions is now coming due.
In an effort to protect homes and encourage new building, governments for decades focused on suppressing fires that occurred naturally, allowing the buildup of vegetation that would provide fuel for future blazes. Even after the drawbacks of that approach became clear, officials remained reluctant to reduce that vegetation through prescribed burns, wary of upsetting residents with smoke or starting a fire that might burn out of control.
That approach made California’s forests more comfortable for the estimated 11 million people who now live in and around them. But it has also made them more susceptible to catastrophic fires. “We’ve sort of built up this fire debt,” Mr. Bonnie said. “People are going to have to tolerate smoke and risk.”