MARY LOUISE KELLY, HOST:
The wildfires in Los Angeles are just the latest in a series of devastating fires across the state. You may recall the 2018 Camp fire in Paradise, California. Scientists say this is part of a trend in the West, one that is fueled in part by human-caused climate change. Here to explain, we have Ezra David Romero, climate reporter with KQED in San Francisco. Hey there.
EZRA DAVID ROMERO, BYLINE: Hey there.
KELLY: So explain away. How is climate change playing into what we're watching in LA this week?
ROMERO: Well, basically, as the atmosphere warms, it's able to hold more water, and it has these two big effects. First, it has longer dry periods and then very wet periods because when it does rain, there's so much more water available. So during those wet periods, we see rapid growth in fuels - things like the grass, brush and trees. And then if a dry period follows, then all that moisture gets sucked out, leaving the fuel super ready to burn. And climate scientists call this hydroclimate whiplash. I know it's a nerdy term, but it basically means rapid swings between super wet and super dry conditions. And new research out this week cements this idea that climate change is making this whiplash even worse.
KELLY: So hydroclimate whiplash is what you said scientists are calling it. Is that what is happening in LA?
ROMERO: Yeah, the LA fires are sort of this perfect example of short-range hydroclimate whiplash. You know, we had two crazy winters of major wet weather causing major flooding in parts of southern California, then it's been pretty not rainy since then. And on top of that, last summer was really, really hot. All those grasses that grew in that wet period sort of all dried out. And this sort of all created the perfect conditions for wildfires to grow out of control. And then on top of all of this, we had extremely strong Santa Ana Winds. You know, we always get those in southern California at this time of year, but this time they were incredibly strong. I spoke to UC Merced climatologist John Abatzoglou about this.
JOHN ABATZOGLOU: The delayed onset of winter rains coinciding with one of these strong widespread Santa Ana wind events - seems like that is the recipe for many of the catastrophic fires that we've seen in southern California.
ROMERO: Yeah, and I should say that, as for the winds themselves, scientists are studying it, but we don't have evidence right now that climate change is making them any worse.
KELLY: Well, that gets, I guess, to my central question. I understand it's complex, but can we say cause-effect? Can we say climate change caused these fires?
ROMERO: Not exactly. You know, climate change is one of the factors at play, but it's hard to say exactly how much. UC Berkeley climate physics professor David Romps says, California has always had these big swings between wet and dry conditions.
DAVID ROMPS: It's hard to say, to what extent the amped-up whiplash from climate change is, quote-unquote, "responsible" for the fires going on in LA right now. But it's consistent with the kind of increase in this variability we expect to see.
ROMERO: Climate change is making the conditions that could lead to wildfire more likely, but there are a lot of other factors, right? Like, so many people live near these wild line (ph) areas like in Los Angeles County. And then there's - we have these historical decisions, like suppressing wildfires. But ultimately, scientists expect climate change to deepen this idea of hydroclimate whiplash, as long as we're burning fossil fuels and adding carbon to the atmosphere.
KELLY: So just briefly, it sounds like what we can expect for California for the West is wildfires will continue, and they may well be getting larger and more destructive.
ROMERO: Yeah, exactly. We might see more of what's happening in Los Angeles over and over again.
KELLY: Ezra David Romero from KQED in San Francisco - thank you, Ezra.
ROMERO: Thanks for having me. Transcript provided by NPR, Copyright NPR.
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