Climate Change Primed LA to Burn — Catastrophically

In a separate analysis released on January 13, researchers at the University of California, Los Angeles, found that climate change could be blamed for roughly a quarter of the dryness of the vegetation that burned in the fires, which they described as a conservative estimate. The study also found that the region’s weather whiplash set the stage for disaster. “Under a warmer climate, you also have what people would call a ‘thirstier’ atmosphere trying to draw up as much moisture as it can,” said Chad Thackeray, a climate scientist at UCLA and co-author of the report. 

And then came the seasonal Santa Ana winds at the start of January, which blew strong and dry. In a matter of hours or even minutes, that air can desiccate the vegetation further still. All it took was sparks for several wildfires to rapidly spread. The Santa Ana winds not only shoved those fires along with breathtaking speed, but also created unpredictable swirls that made the blazes behave erratically. That made the wildfires exceedingly difficult to fight — especially for crews already spread thin fighting on multiple fronts, as the disabled and elderly in particular struggled to evacuate in time. “Realistically, this was a perfect storm when it comes to conditions for fire disasters,” said John Abatzoglou, a climatologist at the University of California, Merced, and co-author of the World Weather Attribution report, on a press call Tuesday morning.

And conditions in Southern California will probably get worse from here. The World Weather Attribution analysis estimates that fire-prone conditions in the region will become 35 percent more likely still if the world warms by 2.6 degrees Celsius above preindustrial levels.

For as much as climate change influenced the Los Angeles wildfires, a few factors operate separately. For one, climate change doesn’t create Santa Ana winds. And scientists don’t expect Santa Ana winds to get stronger as the planet warms — they might even get slightly weaker — though that will require more research to fully tease out. And two, humans spark the vast majority of wildfires in California, be it with electrical lines, fireworks, or arson. And lastly, developers keep building homes in the densely vegetated “wildland urban interface,” where the risk of wildfire is extreme.

This growing risk presents a daunting challenge for communities as they rebuild. Homeowners, for instance, have to keep their yards clear of vegetation and adopt fire-proof building materials, which gets expensive. “Communities can’t build back the same because it will only be a matter of years before these burned areas are vegetated again and a high potential for fast-moving fire returns to these landscapes,” said Park Williams, a geographer at UCLA and co-author of the World Weather Attribution report, in the statement.

Matt Simon is a senior staff writer at Grist. This story was originally published by Grist. You can subscribe to its weekly newsletter here.