Devastating images have emerged of the immense destruction wrought by several fires in the Los Angeles area this week. These will likely be the costliest wildfires in U.S. history, overtaking the 2018 Camp Fire that destroyed Paradise, California.
Many are looking for a clear culprit to blame for this disaster, with climate change being one of the most popular. The fires, however, are the result of both natural and human factors. Climate change may have played a role, but other, more direct causes warrant our attention.
Fire danger is a product of meteorological conditions and fuel (the presence of brush and other flammable materials). You also need an ignition—you can’t start a fire without a spark.
On the meteorological front, Southern California recently experienced an intense Santa Ana wind storm, with widespread hurricane-force winds and gusts over 80 miles per hour in some places. These winds provided the oxygen needed for burning. They drive flames forward, spread embers, and can make aerial firefighting impossible.
Santa Ana winds are an innate part of Southern California’s climate, but it’s not likely that climate change will make them worse. If anything, we expect Santa Ana winds to become less intense and frequent as the climate changes.
Fires need something to burn, so the state of vegetation (the fuels for fires), and in particular how dry that vegetation is, is the other key ingredient. The Los Angeles area has received much less rain than normal for this time of year, which makes vegetation more flammable, but there is little evidence that warming is a primary driver for such a lack of precipitation as we have seen. When Los Angeles does see droughts like this, however, a warmer climate means a drier atmosphere, which works to dry out vegetation and make it more flammable.
Then there is the question of how much fuel there is for fires on the ground. The situation in Southern California Chaparral brush is different than in the forests to the north, where a major problem is fire exclusion—deliberately preventing fires in a region—and the century-long build-up of overstocked forests. Nevertheless, mechanical brush removal and prescribed burning can still be used to reduce vegetation and fire danger, though it comes at a cost to ecosystems. And even assuming the increase in regional temperature that we expect to see by 2050, achieving California’s goal of eliminating 1 million acres’ worth of flammable material per year, along with the federal government’s target of removing such material on 50 million acres over a decade, would reduce the future wildfire threat.
Achieving these goals requires overcoming multiple challenges, including funding constraints, workforce shortages, and logistical issues related to complex land-ownership patterns. The California Environmental Quality Act poses bureaucratic and regulatory obstacles to clearing hazardous materials on state land. The National Environmental Policy Act does the same on federal land. The Forest Service’s NEPA reviews, in particular, often culminate in litigation that delays projects by about three years, on average.
The overwhelming majority of California’s recent wildfires were lit by people. Equipment use (chainsaw and mower sparks), ATVs, dirt bikes, smoking, campfires, barbecues, fireworks, and arson are all common causes. An important part of the solution, then, is to increase public awareness of fire safety. (Such efforts have already proven successful, as human ignitions have probably decreased over the past several decades.)
Utility-caused fires pose an additional risk for future disasters. Southern California Edison has preemptively shut off power in several regions to reduce the risk of powerline-caused fires; this is not an ideal solution, but it does prevent ignitions. In the longer term, California should continue to reduce vegetation around power lines, bury distribution lines, and install power lines that automatically de-energize upon making contact with an object.
Given that extreme fire weather conditions like this will inevitably occur and given that human ignitions cannot be eliminated, protection at the structural level is also vital. Houses are much more resilient to fires if they have no vegetation within five feet of them, and vegetation is sparse and fire-resistant from five feet to 100 feet away. Building codes and “home hardening” also make a difference. Installing non-combustible roofing materials (e.g., metal, tile, or asphalt shingles), ember-resistant vents with mesh screens, and fire-resistant materials for siding (like stucco, fiber cement, or metal) have been shown to be effective in both lab and real-world settings. There is also a synergistic effect, with increased overall effectiveness, as more houses in a neighborhood adopt these practices.
It goes almost without saying that well-resourced firefighting (personal as well as air and ground equipment), as well as high-quality fire-weather forecasting, are critical to slowing down and ultimately containing fires like these.
Devastating events prompt people to search for villains, but reality is more complicated. Climate change may be making fires more dangerous, but it isn’t meaningfully affecting California’s high winds and drought. In any case, the effects of global emissions reductions on fire activity are indirect and will not be realized in the short term. While fire suppression and reducing flammable material are unlikely to be as important in Southern California’s brush landscapes as they would in Northern California’s forests, vegetation reduction would still appreciably reduce fire danger in these landscapes.
We live on a planet that is often hostile to our well-being no matter what we do. Southern California has been fire-prone throughout human history, and it will continue to be. Devastation from natural disasters cannot be completely avoided, and we are often left with partial measures that can only reduce risk, not eliminate it.
Top Photo by David McNew/Getty Images