How Fire Suppression Techniques Can Change As Wildfires Get Bigger

NPR's Kelly McEvers speaks with Professor John Abatzoglou of the University of Idaho about how climate change and decades of aggressive fire suppression are making wildfires bigger and more likely.

KELLY MCEVERS, HOST:

Climate change doesn't cause any particular natural disaster, but it can make them worse. We've seen that with this year's devastating hurricanes and wildfires. With heatwaves, wildfire seasons are getting longer. Combine that with old fire suppression techniques, and you get bigger more devastating fires like the kind we've seen in Northern California recently where more than 40 people have died and dozens remain missing. John Abatzoglou of the University of Idaho studies climate and wildfires.

JOHN ABATZOGLOU: There's really a few ingredients you need for wildfires. It's basically the same ingredients you need for a campfire. You need fuel. You need that fuel to be dry enough. And then you need ignitions. And climate - and specifically, a warmer and drier climate - is allowing for fuels - vegetation to become drier and more receptive to igniting and carrying fire. And that's been a big driver of the increase that we've seen across western forests.

And the other big driver is that we have seen a legacy of fire management and land management since the 1930s. There's been a suppression order in place to basically put out fires where possible. And what that's done is it's allowed for an increase in fuel, an increase in vegetation density, particularly in some of the areas in places like the southwestern United States and the lower elevations in California. You put those two things together, and you've got the ingredients set up for a pretty nasty fire season. And you throw in enough ignitions from humans and lightning, and that's that sets it off.

MCEVERS: These wildfires in northern California have been especially big. How much of that is not related to climate change?

ABATZOGLOU: So my take is that these fires burning in California are not particularly emblematic of climate change. We see a very strong link between fire activity in sort of the forests of the western United States. We think about places like Yellowstone, the Northern Rockies. But the fires in California are a different beast. They're burning in primarily grassland and oak savanna. And the ingredients for fire in these areas are more subtly linked to climate.

But in retrospect, the recipe for this recent firestorm was written on the wall. We had four main ingredients. It was a really wet winter in California that produced a healthy crop of fine fuels that helped carry fire. We then just saw the warmest summer on record in California. That part is consistent with a warming planet. And the effect there is to basically help accelerate the rate which fuels dry out, making them more receptive. And then the big driver, of course, is these Diablo winds, these offshore wind events. And it just so happened that we had these strong wind events that come at a time of the year where the fuels were incredibly dry. And we haven't seen the autumn rains yet.

MCEVERS: You know, you mentioned fire suppression techniques and how they haven't really changed since the '30s. What needs to happen?

ABATZOGLOU: I think what we need to do is take a more proactive approach for dealing with fire. And that may be letting fires burn during years where we have relatively cool, wet conditions - allow them to burn with a watched eye, of course. And as they burn what they'll do is they'll carve up some of the landscape and mitigate against future fires. The idea being is that once the fire burns through an area, you're less apt to have a fire there for, you know, a number of years. So it's a natural way to basically help fireproof or make the landscape more fire-resilient.

MCEVERS: People still want to live in these places, right? Northern California, you know, is a beautiful place to live. How should people learn to coexist with fires going forward?

ABATZOGLOU: That's an important question. You know, we're going to see redevelopment in these areas that have recently burned for obvious reasons. We do need to accept fire on the landscape. And part of that may be, you know, allowing fires to burn during certain years, reintroducing prescribed fire more often and then maybe taking proactive management to creating more fire-resilient structures in homes and communities and potentially also better communicating some of the risks of fires in areas because I think, you know, we do need to consider this as a significant risk, much as like what we do for flooding. It's part of the landscape. It's going to happen. It's going to happen more often with a changing climate.

MCEVERS: John Abatzoglou, associate professor of geography at the University of Idaho - thank you.

ABATZOGLOU: Thank you.

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