Sustainability Corner: How climate change fueled the Southern California wildfires

Photo courtesy of Wikimedia Commons

Recent Southern California wildfires have become 35 percent more likely due to climate change, underscoring the urgent need to address climate impacts on wildfire risks.

A recent report by the World Weather Attribution group, which analyzes the influence global warming has on extreme weather events, explained that the recent Southern California wildfires were about 35 percent more probable to occur because of climate change. 

Due to the dry, windy, and hot conditions created by human-caused global warming, the fires have at least killed 29 people and burnt down more than 16,000 buildings, schools, homes, and stores. John Abatzoglou, a professor of climatology at the University of California, commented on the fires, stating, “This was a perfect storm when it comes to conditions for fire disasters—the ingredients in terms of the climate enabling, the weather driving the fires and the huge built environment right downwind from where these ignitions occurred.” 

To further explain the impact of human-caused global warming, NBC News details that compared to the preindustrial times before fossil fuels were used, there are now 23 extra days of the “dry season” on average each year in the Los Angeles (LA) area. 

Additionally, Park Williams, a professor of geography at UCLA and one of the authors of the report detailing the Los Angeles wildfires, stated that the fires during the cool seasons of Southern California require four conditions: “widespread grass or brush that can burn, abnormally dry conditions, an ignition (which almost always comes from a person; and extreme weather, like the recent windstorm. He described each of those conditions as an individual switch in a system that requires all four to be flipped on for light to emanate.” 

The researchers and authors of the report also found that in today’s climate, the conditions that drove the LA fires are expected to occur once every 17 years. Yet, if there was no climate change, these fires could be expected every 23 years and would likely be less severe. 

While climate change was a factor in the LA wildfires, the researchers and authors of the report note that it was not the sole factor. NBC News states, “The hillsides surrounding Los Angeles are filled with brush that has evolved to burn with regularity, and more people are in these areas today than in the past to potentially start fires via cigarettes, power lines, fireworks, vehicles or other sources.” Furthermore, numerous neighborhood developments have been built in areas that are prone to fires meaning that those houses are “serving as fuel for wildfires and contributing to its rapid spread.” 

One of the main driving factors of the wildfires is the Santa Ana winds, and researchers are still determining whether climate change influences them. Some research suggests that the winds become less intense as the climate warms, while others suggest the wind pattern will continue and possibly intensify during the cold months. 

The fires in Southern California are highly complex, leaving researchers and the report’s authors questioning just how much human-caused global change caused them and how they can slow them down. Los Angeles has a high and distinct human imprint, which means a combination of different aspects leads to the intensity of the wildfires.