Climate Wire | Climate change is the primary cause of wildfire flare-ups in California, with extreme temperatures and dry air causing more intense burning, according to a study released Tuesday by the University of California, Los Angeles.
This research International Wildfire Journal, extracted from state and federal fire data, and synthesized previous reports on climate change and wildfires. Researchers studied fires from 1980 to 2020 and environmental changes over that 40-year period.
“Climate change is the most important factor” in more severe fires, said study author Glenn McDonald, professor of geography and environmental sustainability at the University of California, Los Angeles (UCLA). In particular, he said studies have shown a “significant” relationship between increased air dryness and annual fire coverage.
The analysis comes as California’s largest insurer, State Farm, announced Friday it will no longer insure new homes in the nation’s most populous state due to wildfires and rebuilding costs. rice field. A UCLA study found that 18 of the 20 largest fires on record in California have occurred since 2003.
Between 2002 and 2020, wildfires in California killed 302 people and destroyed more than 60,000 buildings, according to a study. The worst of these hells was a 2018 camp fire in Paradise, northeast of Sacramento, that killed 85 residents.
The study points out that record temperatures have lowered the relative humidity of the atmosphere, increasing the occurrence of “vapor pressure deficit.” This deficit is related to the amount of water that the air can hold and the amount of water that the air can actually hold at that point in time. According to the study, its presence is “a significant predictor of the likelihood of wildfires in California and other parts of the western United States.”
That dry air “has increased at a statistically significant rate during the warmer months of May through October in California, and this trend is expected to continue,” the researchers wrote. The analysis cites previous research that estimated that 68 percent of the increased vapor pressure deficit in the western United States between 1979 and 2020 was likely due to warming.
As climate changes, winter precipitation is also compressed into shorter periods, “contributing to longer fire seasons,” the study said. Warmer temperatures have also accelerated the melting of snow in the Sierra Nevada since the mid-20th century, the researchers wrote.
The most important change, according to the study, is not the size of the fires, but the severity of the fires.
“So when a fire breaks out, it destroys a significant level of vegetation or destroys trees and trees,” McDonald said. “The lower components of plants, herbs and shrubs, and even the crowns of trees, [are] Destroyed. It’s a very serious fire. ”
Asked about the state farm announcement, McDonald said California may need to reconsider where new homes are allowed to be built. Many of the extreme fire sites are located in so-called ‘pure urban perimeters’, where developments adjoin forests and chaparral scrublands.
But McDonald said there have been extreme fires near and in urban areas, including the 2018 Woolsey fires in Ventura and Los Angeles counties.
“In Ventura, an apartment building burned to the ground and a fire occurred within sight of Thousand Oaks City Hall and the theater,” he said. “We’re getting this into places like the suburban landscape, and when fires start in those buildings, they tend to burn very hot.”
Reprinted from E&E News with permission of POLITICO, LLC. Copyright 2023. E&E News provides important news for energy and environmental professionals.
