Understanding the Causes of Southern California Fires

Two people are dead, and 80,000 have been forced to evacuate neighborhoods in Los Angeles thanks to fires raging out of control. According to the media and some scientists, climate change is causing the fires. “Researchers believe that a warming world is increasing the conditions that are conducive to wildland fire, including low relative humidity,” reported the BBC.

But one of the country’s top fire experts disagrees. “I don't think these fires are the result of climate change,” Jon Keeley, a US Geological Survey scientist, told Public. “You certainly could get these events without climate change.”

Keeley has researched the topic for 40 years. In 2017, Keeley and a team of scientists modeled thirty-seven different regions across the United States and found that “humans may not only influence fire regimes but their presence can actually override, or swamp out, the effects of climate.”

Keeley’s team found that the only statistically significant factors for the frequency and severity of fires on an annual basis were population and proximity to development. “We’ve looked at the history of climate and fire throughout the whole state,” said Keeley, “and through much of the state, particularly the western half of the state, we don’t see any relationship between past climates and the amount of area burned in any given year.”

What about scientists who claim that the dry conditions are unusual? “If you look at the past 100 years of climates in Southern California,” said Keeley, “you will find there have been Januaries that have been very dry. And there's been autumns that have been very dry. There have been Santa Ana winds in January. So these sorts of conditions are what contribute to a fire being particularly destructive at this time of the year. But it's not the result of climate change.”