A Tale of Fire (in California)
The California landscape has always been prone to wildfires, and it is a crucial component to California’s many ecosystems. It thins out dead or non-native vegetation allowing native, fire-dependent vegetation — like giant sequoias, chaparral, and oak — to germinate and grow. These delicate ecosystems are adapted to a fire cycle of every 30 to 100 years, but recently California’s wildfires have become noticeably frequent, bigger, and more destructive.
According to Cal Fire, California’s 10 most destructive fires have occurred within the last decade. But what causes California’s wildfires and why are they getting increasingly worse? Before we jump to the conclusion that climate change is the main culprit (and it’s most certainly a major catalyst), let’s dive into the major natural and human elements behind California’s escalating fire threat.
Natural Causes
The first — and most obvious factor — is precipitation, or the lack thereof. California is known for its long, dry summers and historically is prone to periodic droughts. Less precipitation means more dry vegetation that acts as tinder. But with the rise of climate change rainfall can be even more sporadic and droughts more frequent and severe, making the landscape increasingly susceptible to wildfire.
Second — and another obvious factor — is warmer temperatures. Warm temperatures dry out vegetation making the perfect fuel for fire, and with the advent of climate change California is seeing a consistent rise in temperatures. It’s not a coincidence that 9 out of the 10 hottest years in California also saw some of the most destructive wildfires in California’s history according to the New York Times. Also, warmer temperatures means less snowpack in the Sierra Nevada, which is a major source of water for all of California.
The third factor is wind. Over the Great Basin to the Northwest high pressure builds up and is drawn to low pressure zones over the Pacific Ocean. The air is funneled through mountains and warmed by the Valley becoming dry, high-speed winds that rapidly spread wildfires and transform them into firestorms. To the North it is referred to as the Diablo Wind and to the South, the Santa Ana Wind, and with the volatility of rising temperatures, they are bolstered by climate change.
Human Causes
Diving into the human causes, the fourth and arguably the most serious is the legacy of fire suppression. Even though indigenous people had used controlled burning methods for countless generations, the US Forest Service adopted a disaster prevention approach extinguishing all wildfires as they ignited. This policy was buttressed by early conservationist arguments and solidified under the devastation of the Great Fire of 1910. The result is a build up of decades worth of vegetation and forest litter that readily burns into an uncontrollable fire.
The fifth contributor — and arguably as serious as fire suppression — is human development encroaching into uninhabited wilderness. The past century has seen a formidable population boom in California, where now 1 in 8 Americans call home according to the Public Policy Institute of California. The population explosion has pushed residential development into fire prone areas, where controlled burning and beneficial wildfires pose too great a threat.
Similarly, old power lines although not the biggest contributor — only starting 10% of California’s fire according to the California Public Utilities Commission — are certainly worth mentioning because of the attention it’s received. California’s largest power provider, Pacific Gas & Electric, has failed to upgrade its aged power infrastructure, where some power lines are over a century old according to the Wall Street Journal. These antiquated power lines strewn across California’s wilderness cannot withstand the onslaught from the Diablo and Santa Ana Winds, and have triggered some of the most destructive fires in California’s history, including the Camp Fire of 2018 and Kincade Fire of 2019.
In short, more people and infrastructure distributed across the landscape means more opportunities to start a fire, and considering “95% of California wildfires are human caused” according to the California Department of Forestry and Fire Protection, that means there are innumerable opportunities for a fire to be sparked.
The sixth and final contributor I would like to highlight is non-native vegetation. Non-native vegetation, particularly Medditerranean grasses and Eucalyptus, are incongruously ill-adapted to fire landscapes but well suited to California’s climate. Non-natives are quick to dry out and are highly combustible but are more adaptable and quick to root compared to native species. An ecosystem ravished by frequent or severe fires allows opportunistic non-natives to proliferate while suppressing and crowding out more temperamental native species.
Final thoughts
The formula for a wildfire is simple: something that burns + a spark = wildfire. The something that burns could be dried grass, a house, a Eucalyptus grove. The spark could be lightning, a downed power line, a cigarette.
Wildfires will happen regardless of human activity, but humans have undeniably catalyzed and intensified it. Less rainfall, drought, warm temperatures, and high winds are all natural phenomena, but they are becoming more severe because of human-made climate change. And these matters are made worse by erroneous fire suppression policy, inappropriate placement of human development and infrastructure, and the distribution of invasive plants.
Fire was beneficial to the California landscape, but because of humans it is now destroying the landscape.
