An extremely warm summer and fall. An unusually dry winter. Hillsides covered with bone-dry vegetation. And strong Santa Ana winds.In the mix of conditions that have contributed to the most destructive fires in L.A. history, scientists say one significant ingredient is human-caused climate change.A group of UCLA climate scientists said in an analysis this week that if you break down the reasons behind the extreme dryness of vegetation in Southern California when the fires started, global warming likely contributed roughly one-fourth of the dryness, one of the factors that fueled the fires’ explosive spread. Extreme heat in the summer and fall desiccated shrubs and grasses on hillsides, they said, enabling those fuels to burn more intensely once ignited.The scientists said without the higher temperatures climate change is bringing, the fires still would have been extreme, but they would have been “somewhat smaller and less intense.”The conditions that made such catastrophic fires possible are like three switches that all happened to be flipped on at the same time, said Park Williams, a climate scientist who prepared the analysis with colleagues Alex Hall, Gavin Madakumbura and others in UCLA’s Climate and Wildfire Research Initiative.“Those switches are very high fuel loads, extraordinarily dry fuels and an extraordinarily strong Santa Ana wind event,” Williams said. “All of which are mostly due to natural bad luck.”But because all those natural switches lined up, he said, “now the fact that the atmosphere is warmer because of climate change, then the fuels are drier than they would have been otherwise, and therefore the fires are more intense and larger than they would have been otherwise.”The scientists said more detailed peer-reviewed studies that examine the influences of climate change and natural factors will take time, and that they prepared their analysis as a starting point for deeper research.A helicopter makes a water drop on a burning ridge in Brentwood during the Palisades fire Saturday.(Myung J. Chun / Los Angeles Times) Williams and his colleagues examined the last two wet winters, which nourished growth of chaparral and grasses across Southern California. They noted that research has projected more extreme atmospheric river storms because of global warming, but that thus far this trend has not emerged in the data in the western U.S., making any influence of climate change in the last two wet years “highly uncertain.”They analyzed the extraordinarily dry conditions in Southern California, where no significant rain has fallen in eight months. A weather station in Los Angeles recorded just 0.29 of an inch of rain from May 1 through Jan. 8, ranking the second driest since 1877, behind 1962-63, when there was 0.15 of an inch. However, the researchers said the degree to which climate change may have promoted the unusually long dry spell remains “highly uncertain.”The exceptionally hot summer and fall of 2024
Ven. Gen 17th, 2025
