Climate 101 is a Mashable series that answers provoking and salient questions about Earth’s warming climate.
The great blazes burning the West are like colossal campfires.
What do you need to start a campfire? You need to burn some kindling. "The more kindling you have, the better your fire is going to burn," said Valerie Trouet, a paleoclimatologist who researches forest ecosystems at the University of Arizona. "And the drier it is, the better it’s going to burn."
In the Western U.S., the burning is historic. This largely isn't good fire. You've no doubt seen the satellite images of profoundly thick smoke smothering the Golden State, or an airliner taking off through San Francisco's eerie orange skies.
This is explosive fire, at times blowing miles-high smoke plumes into the atmosphere, reminiscent of violent volcanic eruptions. These are blazes capable of burning some 230,000 acres — an area larger than sprawling Dallas — in 24 hours. The rapidly surging flames have moved faster than our expectations, forcing the California National Guard to descend through smoke in helicopters to rescue people trapped by fire.
It's little surprise bad fire is rampant on the West's arid summer landscape. The climate is relentlessly warming in the region, nearly 59 million American homes sit within a kilometer of fires that have burned between 1992 to 2015, and a century of fire suppression to protect these communities has created grossly overgrown forests.
"We didn't need a crystal ball to see this coming," said Jennifer Balch, an associate professor of geography at the University of Colorado Boulder who researches fire ecology. "We hate being right," Balch said, referencing fire scientists. "But we expected this."
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What follows are three big, salient questions and answers about the recent Western fires, which will continue burning in a world that will inevitably keep warming.
1. What's driving the fires, climate change or overcrowded forests?
The debate whether recent fires were fueled by either the warming climate or overcrowded, mismanaged forests can be misleading.
Both are often significant contributors (in addition to other factors like significantly more people on the landscape, fire-prone invasive vegetation, and beyond) to a complex problem, explained eight fire scientists who spoke with Mashable. The two factors are inherently intertwined: There is certainly too much burnable, overgrown forest understory and dead vegetation (collectively known as "fuels"), but a warmer climate has an outsized role in drying out this fuel.
"You can’t ever look at fire without looking at both things," said Adam Coates, an assistant professor in forest fire ecology and management at Virginia Tech. "They're married together."
"We shouldn't polarize it," said Stephen Pyne, a fire historian and emeritus professor at Arizona State University. "Fire is a driverless car. It is a reaction. Different factors at different times and places loom larger."
Yet because the two dynamics of climate change and fire suppression are so influential, they've rightfully earned attention. It's extremely challenging to discern how much either climate change or historic forest mismanagement played a role in a specific fire, explained the University of Colorado Boulder's Balch. Instead, fire scientists look at the big wildfire picture over decades of time. For example, they tease out how much the warming climate has enhanced the spread of fire in a fire-prone Western land.
In the Western U.S., fire researchers have found human-caused climate change, which has driven drier fuels, nearly doubled the amount of forest fire between 1984 and 2015. Separately, fire scientists concluded that wildfire in California has increased fivefold since the early 1970s, largely caused by drier fuels.
"It takes just a little bit of warming to lead to a lot more burning," said Balch.
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In an arid climate, which encompasses much of the West, vegetation is exposed to more heat in a warmer climate, but not more moisture. This amplifies the drying of fuels. That's why climate is such a dominant factor, especially in regions that experience long droughts. "It doesn't matter how much fuel you have," said Balch. "If you don't have a hot and dry climate, you can't burn it."
Yet, importantly, with overgrown forests, you can burn much more of it. Over a century ago, an early chief of the U.S. Forest Service, William B. Greeley, said the major Western wildfires in 1910 were vivid proof that "Satan was at work." By 1935, the U.S. Forest Service instituted the "10 a.m. rule," requiring a fire to be promptly snuffed out the morning after its discovery. The campaign of intense fire suppression in the U.S. ignored that regular surface blazes naturally thin forest understories, so future flames can't grow tall and ignite the crowns of trees. These naturally recurring fires, then, often thwarted future infernos. "In the past, these would be ground fires," said the University of Arizona's Trouet. "They prevented fires from becoming destructive."
So today, more fuel, parched by a relentlessly warming climate, increases potential for out-of-control, raging blazes. And it's only going to get warmer.
"Extremes drive the fire business"
Big fires don't just occur randomly. They happen when extreme fire weather kicks up. This often means hot, windy, and dry conditions. The National Weather Service, for example, will issue "Red Flag Warnings" when conditions for fires to start or spread are imminent or ongoing.
"Extremes drive the fire business," said Mike Flannigan, a fire scientist at the University of Alberta, noting such critical fire conditions often allow big fires to do most of their work in a day or a matter of days (see the deadly Camp Fire).
Importantly, a warming climate doesn't just dry out fuels, allowing them to easily catch fire. It also boosts the odds of more extreme weather conditions, which spread the big, out-of-control infernos.
"Weather is driving things," explained Flannigan. But the weather is getting warmer. An intense heat wave can dry out pine needles and grasses in a matter of hours, Flannigan said. Then add some wind, and all you need is a spark. "There are more extreme episodes due to climate change than there were in the past," he said.
Related Video: Where does smoke go to die in the atmosphere?
2. Didn't millions of acres used to burn in California every year?
You may have heard that a lot more land once burned in California, on the scale of some 5 million acres a year before European settlement, and eventually, systematic U.S. fire suppression. That's likely true. In contrast, 2020 is California's biggest fire year ever recorded, in terms of area, with 3.6 million acres burned as of Sept. 23.
Does this suggest that a "normal" Western fire year might entail a horrendous experience like 2020 (or worse), the air choked with unhealthy to hazardous levels of smoke, major evacuations, and deaths?
No.
Centuries ago, with no one dousing flames from aircraft and helicopters, millions of acres burned in California and the West each year. But this didn't mean big, bad fires.
"A large area burned does not mean large fires, as in megafire," said Arizona State's Pyne. The past burning was often good fire, meaning light burning on the forest floor. "They were benign fires," explained Pyne, not major forest infernos sending apocalyptic, dark smoke plumes into the sky.
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These precolonial fires were also the type intentionally used by Indigenous people, who stewarded land to restore ecosystems or keep habitats healthy and diverse. "They were the type of fires you could stand around and walk next to without burning yourself," said Don Hankins, a professor of geography and planning at California State University, Chico. "I've seen insects walk through them without getting burned," said Hankins, an expert in Indigenous fire treatments.
Yes, there were some big fires in the 1800s and in 1910, the exceptionally dry year of The Big Burn. But these megafires had bounties of human-created fuel to ignite, explained Pyne, specifically the remnants of widescale logging and cleared land.
It's clear the West burned regularly in the past, in some places about every 10 years. But these weren't the same fires we're seeing today. Modern megafires, enhanced by flammable non-native grasses that blanket many Western landscapes, shouldn't be considered normal.
But, still, the past tells us we must aggressively steward our forests with managed burning, significantly more than we do today.
3. How can we stop the ruthless cycle of bad fires?
Just ask any oceanographer: Earth will keep warming through at least the next few decades, even if we ambitiously slash carbon emissions. That's because the ocean absorbs over 90 percent of the heat humans trap on Earth, and like a battery, the seas will gradually release this energy back into the atmosphere for years into the future.
Then, there's the other elephant in the room. Atmospheric levels of the potent heat-trapping gas carbon dioxide are the highest they've been in at least 800,000 years, but more likely millions of years. CO2 stays in the atmosphere for centuries, so we've likely baked in warming for quite some time.
This means drier fuels out West, and more fire. Yet, critically, we have the ability to remove many of the fuels that drive destructive fires. And as 2020 has proved, we must.
"It's important to realize that the no-fire scenario we’ve gotten used to is no longer on the table," said the University of Arizona's Trouet. "That is something we created artificially in the 20th century. We’re suffering the consequences now."
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But because millions of Americans live in or near fire country, wildfire agencies will continue to suppress fires. This means we must introduce, or prescribe, fire onto landscapes during controlled windows of opportunity (like certain times in the spring when it's not critically hot and dry) to vastly reduce the amount of fuels available to burn. "We have a responsibility to manage that," said Virginia Tech's Coates. This can't be half-hearted. We'll need to burn, regularly and consistently, like Indigenous cultures centuries ago.
"We're going to have to become big burners again," said John Bailey, a forestry expert at Oregon State University.
If there's less vegetation to burn on the ground, flames won't have the fuel to leap into the crowns of trees, igniting tremendous fires. "That’s why fuel treatments work," explained Bailey.
Setting fire in beloved forests might be an uncomfortable pill to swallow. Prescribed burning has even decreased over the last two decades. But that's the way forests must exist. "Oregon's forests are magnificent," marveled Bailey. They protect freshwater, store carbon, provide homes for wildlife, supply wood for homes, and grant an inherent spiritual value to Oregonians, he said. "The forest is all those things — and all those things at once," emphasized Bailey. "But it's also fuel. It's fuel and it is going to burn."
"It is short-sighted to think your favorite area to hike isn’t going to burn," he added.
Amid a hellish 2020, California has committed to introducing good fire to the landscape. The state, in an agreement with the U.S. Forest Service, has agreed to treat 1 million acres of land annually by 2025. They hope to achieve this by "expanding and accelerating the use of prescribed fire."
"It's fuel and it is going to burn."
The government-led effort, which says it will seek out collaboration, might consider inviting guidance from fire experts like Chico State's Hankins, who has a rich knowledge of how Indigenous people once treated big swathes of land with good fire, centuries ago. "You have to have the knowledge to do it," Hankins said. "It's very detailed." For example, Hankins, who has burned in essentially all California ecosystems — woodlands, forest, chaparral, and wetlands — described how he knows when and where to burn on a specific landscape. It's an ancient, proven tool.
"People in the time when the Spanish arrived had fire as a tool," he explained. "At this point, we don’t have fire as a tool to use." But Hankins doesn't view it as "managing" the land. He prefers "stewardship."
"Stewardship implies that you recognize you’re just part of the picture," Hankins said.
Burning 1 million acres each year, in California alone, is a lofty goal. "That's laudable," said Alberta's Flannigan. But treating the land with good fire may prove unpopular. "People don't want smoke, chambers of commerce don't want smoke," Flannigan said. It's also hugely expensive to steward (or treat) vast swathes of land, such as all California's forests. "It's a complicated operation," said Balch. She suggests focused burning near and in regions where people live, to thin the fuels where fire will inevitably come to town, or the suburbs.
Sure, no one likes smoke. But anyone living in fire country has a critical decision to weigh: "Do you want all your smoke at once coupled with the destruction of entire communities?" asked Jennifer Marlon, a research scientist at Yale University's School of Forestry and Environmental Studies. "Or do you want it to happen in small areas during specific times so you can plan and prepare?"
Good fire, of course, isn't the only solution to avoiding big blazes. Another critical fix is avoiding sparks during the summer and fall, when modern fires are liable to become out-of-control infernos.
"All human-caused fires are preventable," emphasized Flannigan. (Some 84 percent of wildfires in the U.S. are caused by people.) When there's critical fire weather, it would be wise to close forests for a few days, he said, just like California closed all national forests earlier in September. It's a way to avoid a car, tool, stove, or cigarette sparking the next historic blaze. Downed, potentially faulty power lines, meanwhile, sparked thirteen fires in Oregon in early September. Power blackouts, like in California, could be necessary amid critical fire weather (though blackouts come with serious threats for those with medical needs).
But all of these solutions, and many others like strategically protecting towns from fire, demonstrate that we're not helpless. We can limit the flames. And, importantly, we can live with good fire. "Earth is a fire planet," said Virginia Tech's Coates. "You can have peace with the fact that it is our natural ecology."
"We’re going to have a few bloody noses before we change," said Flannigan. "Perhaps this year is one of those bloody noses."
