The Summary
- The hot, dry, windy conditions that led to the recent Southern California fires were about 35% more likely because of climate change, a new report says.
- The findings come from the World Weather Attribution group, which analyzes the influence of global warming on extreme events.
- The fires have killed at least 29 people and destroyed more than 16,000 buildings.
An international committee of scientists warned Tuesday that climate change made it more likely that the catastrophic circumstances that permitted the recent flames to rage throughout the Los Angeles area would occur.
According to a recent research from the World Weather Attribution project, which examines how global warming affects severe events, the hot, dry, and windy conditions that preceded the fires were almost 35% more likely as a result of human-caused global warming.
At least 29 people have been killed by the fires, which began amid a fierce windstorm and after nearly no rain had fallen in greater Los Angeles since the spring. More than 16,000 buildings, including houses, shops, and schools, have been set on fire.
According to John Abatzoglou, a climatology professor at the University of California, Merced, who contributed to the report, “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.” He made this statement during a news conference.
According to the paper, the Los Angeles region now experiences an average of 23 additional days of dry season annually compared to preindustrial times before the widespread usage of fossil fuels. This increases the likelihood that fires will occur during seasonal Santa Ana winds.
“Fires during cool seasons in 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,” said Park Williams, a geography professor at the University of California, Los Angeles and one of the report’s authors. According to him, each of these circumstances functions as a separate switch in a system that needs to be turned on for light to shine.
According to Williams, the artificial warmth brought on by climate change caused by humans is making the light brighter.
In order to assess how a warmer atmosphere is changing the chance of fire weather—that is, conditions that raise the risk of wildfire—the report’s authors examined weather and climate models. Additionally, they monitored the evolution of a statistic known as the Fire Weather Index. The index monitors wind speeds, temperature, and relative humidity—all of which increase the risk of fire.
The researchers discovered that, given the current climate, the types of conditions that caused the fires in the Los Angeles area should only happen once every 17 years on average. According to the analysis, in the absence of climate change, such conditions would have been expected once every 23 years and would have been less severe when they did occur.