Science and Tech


Fire researchers are highlighting the human role in wildfires

Researchers say the human role in wildfires is increasing, and they hope a new study helps sound the alarm before more homes go up in flames.
Posted at 8:56 PM, Feb 20, 2023

More than a thousand homeowners in Louisville, Colorado know what it's like to lose a home to wildfire.

"It's not just a home; it was a life that I had before I was born, when I was born and everything after it. And it's all in one spot, and now it's all gone. And it's tough to leave it go," said Janet Jensen-Wolf, a victim of the Marshall Fire.

In the days after the December 2021 Marshall Fire, University of Montana fire ecology professor Phil Higuera was on sabbatical nearby in Boulder. Ironically, he was researching the amount of homes lost in the western United States to wildfires the two decades prior.

"It absolutely had a dramatic effect on me," Higuera said. "To have it play out right in the community that I was embedded in for the sabbatical was, it was was frightening and a little bit shocking."

Fire has consumed Higuera's professional life for 22 years, but he wanted to take a closer look at how humans are impacting fire trends in the West.

"Largely, we're seeing increasingly these negative human impacts of wildfires," Higuera said.

Higuera's team had a hunch that wildfires were destroying homes at a higher rate in the last decade than in previous years. But they wanted to know by how much, and what role humans played in the numbers. They pored over data from more than 15,000 wildfires between 1999 and 2020.

"We focus a lot on that one statistic of how much area burns, and our hunch was that area burn doesn't tell the whole story and, in fact, can be misleading," Higuera said.

The team took into account the number of acres burned and increased growth in the West, with more people moving to the edge of urban areas where wildland begins and development meets nature.

3D-printed homes could be the future of wildfire recovery

3D-printed homes could be the future of wildfire recovery

3D-printing technology allows houses to be built in less time and with a fraction of the supplies and workforce needed to build traditional homes.


But something shocked Higuera and his team: the increase in structure loss is actually outpacing the increase in area burned and the increase in people.

"It's not just that fires are now burning into places where they have in the past and there happened to be homes there or there are homes in places where fires used to burn; it's the combination of both and the human component," Higuera said.

The study found western wildfires destroyed 246% more homes and buildings between 2010 and 2020 than the decade before. And as Higuera says, the current wildfire crisis has human fingerprints all over it.

"About 76% of all the fires that end up resulting in some sort of home or structure loss, those fires are started by us — either, in most cases, by accident, and either directly or indirectly through things like infrastructure, power lines falling down backyard burning, the cigarette butt chains dragging on the on the highway, you name it," Higuera said.

The research also showed most of the destruction happened in the 2017, 2018 and 2020 wildfire seasons. Maybe not to surprise: California dominated the pattern of increased structure loss, making up 77% of the more than 8,500 buildings destroyed. But Higuera says the trends point to an increase in nearly all western states.

"We would be misguided if we just thought of this as a California problem and didn't kind of look ahead on the radar and see that many communities in many states are moving in that same direction," Higuera said.

What might be surprising is that 88% of the western wildfires between 1999 and 2020 didn't destroy any buildings. A majority of the area burned started with lightning and often in remote areas; that's what fire researchers call beneficial fire. It's part of why the U.S. Forest Service reversed a decades-old full suppression strategy. It means understanding what's known as the fire paradox.

What's driving longer wildfire seasons in the U.S.?

What's driving longer wildfire seasons in the U.S.?

Fire season normally follows the heat of the summer, but now it's stretching nearly year-round.


"The counterintuitive aspect is all happening all the time with fire," said Mark Finney, Missoula Fire Sciences Laboratory research forester. "If you have a fire problem in our wildlands, chances are you need more fire in order to solve it, not less. We don't have a choice about fire. Every year we prove we do not have the power to choose not to have it. The only power we have is when to have it and what kind to have, and that's it."

Experts agree solutions include prescribed burns to thin fuel in forests and creating defensible spaces around homes. This means whole communities making changes to how they build — with more fire-resistant material and in spatial patterns that give firefighters safe access — and also where they build — in places that minimize the chances of unintentional fires, like near power lines.

Higuera says if nothing changes, two things guarantee these trends will keep rising: climate change and human behavior as we continue expanding in the West.

"It's relatively easy to play this out in the future," Higuera said."Our hope is that by sharing this information, we can pull some levers that will change the relationships that we've uncovered and see over the past 20 years so that the next 20 years don't have all the same factors influencing things."

It's new research like this with clear actions everyone can take now that can reduce the likelihood of another disaster like the Marshall Fire, though that wasn't even in this data.

Next, the same researchers want to take it one step further to break down different human causes for wildfires and see which is the most destructive.