UMAIR IRFAN: This is Science Friday. I’m Umair Irfan, sitting in for Ira Flatow. Wildfires are a fact of life in states like California. But as we’ve seen over the recent years, they’re changing in dangerous ways.

Last year, a record 3.2 million acres burned in California, while nearly two million more burned in Oregon and Washington. This year, California has seen another two million acres burned, and the season is far from over. The Dixie Fire, north of Lake Tahoe, has by itself burned over 900,000 acres in northern California. If it makes it to a million acres, becoming a gigafire, it will be the second on record ever to do so, right behind last year’s August Complex Fire.

Meanwhile, the Caldor Fire, south of Lake Tahoe, has topped 200,000 acres. Research is increasingly clear that wildfires are burning hotter, fire season is lasting longer, and fire risk is increasing in places that aren’t used to it. Meanwhile, more people are in harm’s way. In California, 11 million residents live in high wildfire risk areas, and the state’s population is growing.

All the while, humans are making these risks worse through building practices, poor forest and wildland management, and climate change. So if climate change and other human factors are worsening wildfire risks, what can we do about it? Should homeowners pull up stakes and retreat?

Or can they hold their ground and adapt? My next guest is someone who thinks a lot about these questions, Dr. Crystal Kolden, a fire scientist at the University of California, Merced. Welcome back to Science Friday, Crystal.

CRYSTAL KOLDEN: Thank you for having me back.

UMAIR IRFAN: So how would you put these fires this year in context compared to some of the record-breaking seasons we’ve seen in the past? Are they par for the course? Or are they still surprising in some ways?

CRYSTAL KOLDEN: They’re surprising in some ways and not so in others. There is a tendency to focus on how big the fires are because that is one of the statistics that people understand, and it’s readily available. For fire scientists, often what we’re more interested in is looking at how fires are burning across different landscapes, between forests and shrublands and grasslands, and trying to figure out what are the things that are outside of the normal range.

And what are the things that are within the normal range? And this year’s fires have certainly surprised us with some of the types of fire behavior we’ve seen, some of the burning that we’ve seen, particularly at high elevations. And, you know, the thing that is not surprising in many ways is how these fires have grown larger because this has been projected by many of our fire climate models for quite a few years.

UMAIR IRFAN: Is there an example that stands out in your mind about how these fires have been behaving in unusual ways?

CRYSTAL KOLDEN: I’ll use the Dixie Fire and also the Caldor Fire, which of course threatened the South Lake Tahoe region. And those fires were both fires that burned over the Sierra Nevada mountains this year. And prior to 2020, there had never been a modern wildfire that burned up and over a mountain range.

And last year, the East Troublesome Fire burned over the Rockies in Colorado. That was a first. And then this year, we saw our first Sierra Nevada fire that burned over the crest, being the Dixie Fire, followed shortly by the Caldor Fire, also burning up and over the crest.

So this is really something that we noticed that was unusual. And one of the key things is that we have seen really active burning at night and at high elevations, where historically we have not seen that active of fire behavior. And that is really indicative of how dry it has been this year, how dry the vegetation is, how warm and dry it stays at night. And that is producing this really active fire behavior that simply exceeds the capacity of fire suppression resources.

UMAIR IRFAN: So we can’t simply look at the number of acres burned. We also need to consider the ecosystems, the timing of the fire, and the nature of the burns themselves when evaluating these blazes.

CRYSTAL KOLDEN: Yes. If our goal is to prevent wildfire disasters and specifically things like loss of life, loss of homes and infrastructure, and loss of some of the really critical facets of ecosystems that we highly value– things like having clean water come out of these forested watersheds or certain species like giant sequoia, which are currently being threatened by fires in Sequoia National Park– if we really want to prevent those types of disasters, we have to separate how fires are burning to produce those disastrous outcomes and how they are burning in other places and maybe even still doing a lot of ecological good. And one of the things that I and many of my colleagues have tried to showcase is that, even on these really large fires– like the Dixie Fire– there is a lot of actually beneficial fire being reintroduced in a lot of these forests, in places where it was excluded for over a century. And these forests are fire-adapted.

So much of that acreage is actually beneficial. And we have to recognize that in order to be able to say, all right, what we want is to minimize not the fire itself, and a century of trying to put fires out has taught us that we simply can’t do it and it’s actually really detrimental to ecosystems to try and do that. But rather we want to support beneficial fire and minimize and mitigate those fire disasters.

UMAIR IRFAN: To your point, though, about protecting homes, a lot of people who are watching this from afar, seeing wildfires occurring, you know, year after year in very similar places, a lot of people say– are asking, you know, should we even be living there to begin with. Shouldn’t people retreat? And, you know, you often hear about this idea of a managed retreat in the context of coastal areas and sea-level rise. But do we have to do something similar with fire? Or is there more to think about here?

CRYSTAL KOLDEN: I think that fire is much more complex when we’re talking about managed retreat. When we’re looking at California and we’re talking about a place where there is already another major disaster that befalls Californians, which is earthquakes, and we don’t ask people to no longer live on fault zones in California, right? We basically, stemming from the 1906 earthquake in San Francisco, have figured out how to engineer and mitigate a lot of that potential earthquake damage, such that subsequent earthquakes in 1989 and 1984, we did not have the level of destruction that was seen in 1906.

When we talk about wildfire managed retreat in a place like California or really anywhere else vulnerable to fire, does it make more sense to just tell everybody to move somewhere else, where there’s another disaster or it’s far too expensive for them to live? Or does it make more sense to say, OK, can we engineer and mitigate this environment, these homes, this community, so that the wildfires that we know are going to burn don’t have as disastrous of outcomes? And I think what we have seen in the last few years is that we can do that.

UMAIR IRFAN: Last week, we saw people evacuating South Lake Tahoe as the Caldor Fire approached. That’s a major tourist area, and it looked like it was under serious threat. But it seems that area’s defenses held. And since then, the fire has been better contained. What happened and can we learn from this?

CRYSTAL KOLDEN: What I hope people take away from watching what happened in South Lake Tahoe the last few weeks is that they engineered a positive outcome. The reason that that success occurred was due to the many, many years of work that have occurred in the forest just around the edges of the city and the amount of fuel reduction work that was done, the prescribed burns that were done, and all of the treatments that allowed firefighters to work safely and be combating much lower flame lengths and much less energetic fire, as the Caldor Fire moved towards South Lake Tahoe. That is a landscape engineering success that saved the vast majority of homes in the Christmas Valley, Meyers, South Lake Tahoe area.

UMAIR IRFAN: We spoke last year to members of the Yurok Tribe and other Indigenous cultural fire practitioners. You know, many Indigenous peoples who have lived in California and the West conducted controlled burns as part of their cultural practices for thousands of years. So it seems there is a precedent for what you’re describing.

CRYSTAL KOLDEN: Yeah, when we look at what Indigenous people have done in terms of fire stewardship and how that is part of a larger holistic land stewardship ethic, what it tells us is that, as people, we can live with fire in these landscapes. But what we see across much of the country is that Indigenous groups used cultural fire in so many different ways to basically steward the landscape that they were living on and to ensure that they didn’t lose their villages and the landscapes that they were utilizing for subsistence living, right, to wildfires. Indigenous practitioners basically came up with the first approaches to doing burns around the Indigenous version of the wildland-urban interface.

A lot of the cultural burning that was done was basically to protect the village. So we can learn from that, right? And we can actually empower the people that still hold that knowledge today, like the Karuk, like the Yurok, and other tribes across the West. There are so many knowledge holders that would love to be able to restore a lot of those cultural burning practices. And right now, there are many barriers to that happening. If we can learn from them and listen to their deep knowledge, then we can learn to live with fire in these places.

UMAIR IRFAN: Now casting sort of a wider lens to the whole US and maybe the whole world, are there any examples of fire mitigation or fire risk reduction that have done pretty well? Are there any examples or just kind of case studies that are places that we should look to?

CRYSTAL KOLDEN: Even within our own country, in the US, we look at the southeastern US. There is a very, very strong prescribed fire program in the southeastern US. They burn over five million acres a year there, and that has really minimized the number of huge destructive wildfires that the Southeast has. When we look at places in Europe, when we look at places in Africa, where there are strong burning programs, oftentimes in combination with agricultural programs and grazing programs, what we see is that they are, even under climate change, able to effectively mitigate the most negative impacts of wildfires, right? And it allows wildfires to do what they have always ecologically done and be beneficial for many of these ecosystems.

UMAIR IRFAN: All of the things that you’re describing make a lot of sense. And I imagine if you told most people about them, they would agree with you. So what’s holding us back from implementing this? What kinds of policy changes or other kinds of tactics do we really need?

CRYSTAL KOLDEN: There are a couple of key things that have to change. There are certain policy barriers that make it difficult for us to utilize larger amounts of prescribed fire or even do the types of mitigation work beyond prescribed fire that we know are effective in reducing fire behavior. So as an example, in a lot of places, there are HOA rules in certain communities that are actually not very conducive to doing the type of work around homes.

If there’s architectural requirements that are not conducive to more of a hardened home type of neighborhood, that’s a very localized barrier, right? Cost is also a huge barrier. But that’s less of a policy issue. Many communities, there would be enormous benefits from introducing things like goats. They can do a substantial amount of fuel reduction.

But for obvious reasons and some of this is sort of legacy in the US, there are a lot of restrictions against having farm animals in your community. You know, and at landscape scale, there are a lot of policy barriers around prescribed fire because it is a risky thing, right? We’re intentionally lighting a fire.

And one of the really heartening things that has happened just recently is that there are a couple of bills that have been working their way through the state legislature in California and are waiting for Governor Newsom’s signature. And they are both directed specifically at changing the liability laws around prescribed fire, such that instead of having someone be fully liable for anything that might go wrong on a prescribed fire, it instead changes the liability such that if you are doing everything right, we recognize that there is a greater liability in not doing these prescribed burns and instead waiting for a wildfire to come along. And it allows us to do more of the type of prescribed burning that we know is very, very effective in reducing wildfire disaster outcomes.

UMAIR IRFAN: I’m Umair Irfan and this is Science Friday from WNYC Studios. Populations are growing, and average temperatures are still rising. Are we running out of time to implement these measures?

CRYSTAL KOLDEN: Running out of time implies that there’s sort of a date after which nothing we do will help. And the reality is that everything that we do now will help. You know, and this is actually the second piece of the puzzle for how we need to change our thinking about this and change the way that we approach implementing a lot of these mitigation measures, which is that we need a cultural shift.

We need a cultural shift in the way people look at fire on this landscape. And instead of having Californians or even Westerners in general look at fire as something that can be prevented and that is bad all the time, right, instead we need to start looking at fire as something that is inevitable but doesn’t have to be bad. And actually it can be very, very beneficial when it is occurring in a way that is not producing disastrous outcomes.

But if we use more prescribed fire, we can control how much fuel is on that landscape. If we introduce some of these other mitigation measures, like understory brush removal and grazing, we can control the level of fuel on the landscape. And if we harden our homes and communities and have that be a major investment priority for the state and the Fed, then we can actually reduce the dangers and the risks of fire to our structures and our infrastructure. And the thing is, it’s empowering to think you can do something about it.

UMAIR IRFAN: I think your point that everything we do will help is a really important one. Thanks so much for joining us. And I really appreciate all the input that you provided today.

CRYSTAL KOLDEN: Thank you so much for having me. I always enjoy talking about this topic.

UMAIR IRFAN: Dr. Crystal Kolden, assistant professor studying fire science at the University of California in Merced.

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