Climate change brings hotter, drier winds – ramping up intensity of wildfires in the West

LOS ANGELES – It seemed as if Southern California was ablaze in December 2017. Four big wildfires were chewing through wildlands from southern San Diego County to Santa Barbara, scorching hundreds of square miles and destroying or damaging thousands of homes.

It could be a sign of things to come. Many scientists think climate change is a major contributor of wildfires in California and across the nation, particularly in western states like Colorado, Arizona, Nevada and Utah.

“Wildfire is a really interesting sustainability issue,” said Alex Hall, a climate scientist with the Institute of the Environment and Sustainability at UCLA. he also directs the Center for Climate Science and is with the university’s atmospheric and oceanic sciences department.

“For the past 200 years or so, we’ve been burning fossil fuels that has led to an increase in greenhouse gases in the atmosphere,” Hall said. “Greenhouse gases trap heat, and that has led to a steady warming of the planet that has been accelerating in recent decades. Fires are driven by dry and hot winds, and when winds become hotter and drier, that leads to greater fire risk.

“Climate change also … tends to dry out vegetation during our hot summers and it dries it out more as the climate warms more, and so that can create a greater risk for fire as well.”

Hall says it is a challenge trying to fight blazes where hillside wildlands and urban sprawl intersect. These are typically places in and around areas like Los Angeles, Denver, Phoenix and Salt Lake City. LA is the worst of these cities, he says.

“What happened with the fires last season was a great example of what’s to come with fire,” Hall said. “We had a really, really big wet season in 2016-2017, and that led to a buildup of vegetation. That vegetation dried out over the course of a very hot summer in 2017, and then the rainy season did not arrive as it should have, and so by the time we got to December, we had these very hot and dry Santa Ana events that occurred, and that was the perfect condition for a very large fire.

“And climate change will increase the frequency of those types of events. Climate change increases the dryness of the winds when they occur. It increases the temperature of the winds when they occur, and it also increases the swings between very wet and dry years. We’re beginning to see the climate-change signal emerge, certainly in the climate record and then at the same time the fires are also becoming unprecedented. We’re seeing fires that are setting records in terms of their size and their intensity, and our ability to manage them is becoming less and less.”

To really get an idea of what Hall is talking about, consider the Thomas Fire in northern Ventura County, the worst California wildfire in state history. It began Dec. 4, claimed two lives, destroyed 1,000 structures and was not fully contained until Jan. 12. Nearly 282,000 acres were charred.

During December, Southern California experienced Santa Ana winds near 70 mph – something not seen in decades. What started the Thomas Fire isn’t known, but it raced through the region at a frenzy. Winds carried dense plumes of gray smoke miles from where the fire was burning. More than 500 engines from all over California were stationed at the Ventura County Fairgrounds along with more than 2,500 firefighters.

Chris Harvey of the Sacramento Fire Department was part of that team.

“We’re talking about a fire that’s over the size of the city of Detroit at this point. It’s likely to be much larger than that,” Harvey said.

Weeks later, the Thomas Fire had engulfed an area larger than New York City.

The December 2017 Thomas Fire burns in the hills above Los Padres National Forest. (Photo: Stuart Palley for the U.S. Forest Service)

“It is like a war zone,” said Gretel Compton of Ventura County, whose home was partly destroyed. “You’re driving through areas where they’re completely burnt out and black. It looks like a bomb went off.

“I want to go home. I want to see what the damage is. We have lost part of our house. I’m just so up in the air. I don’t know what to do. Where do you start? I have no water. I have no power. I’m on a well. All of that stuff is burnt. Other friends and neighbors have lost everything, everything, everything, and now they have to start from scratch and it’s just so heart-wrenching.”

Wildfires can have devastating consequences, including loss of life, destroyed homes, financial losses and air quality damaged by tons of carbon dioxide.

But wildfires also can benefit the environment, climate scientists say.

They can rid forested areas of dead and decaying matter that provide fuel during dry periods. Fires can help balance the ecosystem by destroying diseased vegetation and dangerous insects, like the bark beetle, which has decimated millions of acres of California forest over the past decade. Fires even regenerate seeds for trees that require intense heat every few years to sprout.

“Wildfire is a natural part of our landscapes,” Hall said, “and our natural landscapes actually need wildfire to regenerate, and we have to learn how to coexist sustainably with wildfire going forward – and that’s something we haven’t done a great job with in California.”

Harvey, the Sacramento firefighter, noted Southern California’s “long history of destructive and catastrophic wildfires.”

“We do take a very personal feeling to what’s going on here,” he said. “So I hate to say this, but this could continue to be a very explosive and expansive event.”

Hall said he was “concerned about our sustainability relationship with fire.”

“The most important thing that we can do to combat climate change is to stop burning fossil fuels,” he said. “We need to replace those energy sources with renewable energy sources, and examples of those are solar power, wind power, hydro power. Those are the things we need to rely on in the future. We will see less warming in California and that will lead to less of an impact on fire. That will lead to less of an increase in fire risk, and that will help us manage this increasingly difficult situation that we have with wildfire.”