Fire crews are still working to contain the deadly inferno that leveled the town of Paradise, virtually wiping it off the map. Thousands of people are homeless, living in tents, trailers and parking lots. Dozens are dead. Hundreds are still missing. And massive, choking plumes of smoke continue to blanket Northern California.
Forecasters say rain might arrive by Thanksgiving to clear away the smoke and mercifully reduce fire danger. But the optimism is tempered by a grim reality. Scientists say as temperatures continue to warm, drying out brush, grasses and trees into explosively flammable fuel by late summer and autumn, catastrophic fires and the unhealthy smoke they spew hundreds of miles away will almost certainly become more frequent in California and across the West in the coming years.
“Climate change is not the cause of these fires,” said Park Williams, a climate scientist at Columbia University’s Lamont–Doherty Earth Observatory in New York. “But the warmer atmosphere is causing most fires to be harder to contain. They are burning bigger and hotter.”
The numbers are stark. California has warmed roughly 3 degrees Fahrenheit since 1980 during the autumn months of September, October and November. Rainfall in those months has fallen by about one-third over the same time. And the result has been a state increasingly on fire.
From 1980 to 1990, roughly 300,000 to 400,000 acres a year burned in California. Last year, 1.4 million acres burned. This year, so far, 1.8 million acres — an area six times the city of Los Angeles — of federal, state and private land has been incinerated. Similar trends are afoot in other Western states.
“We don’t even say ‘fire season’ any more. It’s year round,” said Scott McLean, deputy chief of Cal Fire, the state’s primary firefighting agency. “The climate change we are dealing with is related to that.”
Put another way, 15 of the 20 largest fires in California history have occurred since 2000. Four of the five largest have happened since 2012. And the two all-time biggest in terms of acres burned — the Mendocino Complex Fire centered in Lake County this summer and the Thomas Fire in Ventura and Santa Barbara counties last December — both happened in the last 12 months.
“We’re in a new abnormal,” a grim Gov. Jerry Brown said last Sunday at a news conference to discuss the Paradise disaster. “Things like this will be part of our future. Things like this and worse.”
Even Ryan Zinke, Interior Secretary in the Trump administration, which has been skeptical, if not hostile, of climate science, conceded the changing conditions on Wednesday during a visit to Paradise.
Zinke said he did not “want to finger point” and said there were multiple reasons for the worsening fires. But those include the fact that “fire seasons have gotten longer and the temperatures have gotten hotter,” Zinke said.
The climate is warming because burning fossil fuels traps heat in the atmosphere. The 10 hottest years on Earth since modern temperature records began in 1880 all have occurred since 1998, according to NASA and NOAA. But climate change is not the only reason for the growth in wildfires, scientists and firefighters say.
Centuries ago, lightning and Native Americans clearing land burned more acres a year than are burning now in California. But those fires were mostly low-intensity affairs, helping clear dead underbrush. Today, because fire crews have put out blazes for generations, many forests have so much dead and living vegetation that they often explode out of control, wiping out large trees and seeds.
More than a century ago, it was not uncommon for whole towns to burn down. The 1871 Peshtigo Fire killed about 1,500 people in Wisconsin and Michigan, with so many fatalities that there weren’t enough survivors in some communities to identify the dead. The Great Fire of 1910 burned 3 million acres in Washington, Idaho and Montana, killing 86 and sending smoke plumes to New York. Afterward, the U.S. Forest Service set a policy of putting out fires by 10 a.m. the next morning, and radios, helicopters, planes and other equipment improved safety dramatically over the generations.
But now, with hotter, larger fires growing ever more intense in a warming world, creating “fire tornadoes” and walls of flame hundreds of feet tall, whole towns could again burn down, fire experts say.
“This is the kind of urban conflagration Americans thought they had banished in the early 20th century,” wrote Stephen Pyne, an Arizona State University fire historian, last week, of the Paradise disaster. “It’s like watching measles or polio return.”
Earlier this year, California lawmakers passed a bill that promises $1 billion in state funding over the next five years in grants to cities, counties, fire departments and nonprofit groups to thin overgrown forests around towns, cut fuel breaks and conduct controlled burns to restore some natural balance.
Scott Stephens, a fire scientist at UC Berkeley, has estimated that the state and federal government will need to increase such thinning and controlled burning tenfold from current levels to make a difference. That will cost billions of dollars.
Another challenge is population growth.
From 1990 to 2010, there was a 41 percent increase in the number of houses in America’s “wild land-urban interface” — the area where homes and forests meet, and where wildfire problems are most pronounced, according to a study last year led by the University of Wisconsin. One in three Americans now lives in those fire-prone areas.
Add to that California’s 2012-2017 drought, which killed 129 million trees, mostly in the Sierra Nevada and its foothills. That left enormous amounts of dead vegetation, primed to burn.
McLean, of Cal Fire, said the solution going forward must be more vigilance. More education campaigns to teach people how to create “defensible space” around their homes. More forest thinning. More controlled burns. More escape route drills. More firefighting equipment.
Others say that tougher building codes are needed. Some suggest burying power lines, which cause many of California’s worst fires. But that costs 10 times as much as stringing them on poles. And there are 176,000 miles of power lines in California.
While 3 degrees of warming in the past 40 years might not seem like a lot, it makes a big difference in the moisture levels of plants, said Daniel Swain, a climate scientist at UCLA. Moisture levels in vegetation across California remain today at some of the lowest levels ever recorded, even as autumn wind conditions increase fire risk.
Normally, by mid-November, the ground and the vegetation is damp. So sparks from cars, power lines and campfires have a difficult time growing into large fires, Swain noted. But increasingly, the storms that once soaked California have been blocked in the fall and spring months because of ridges of high pressure in the Pacific Ocean. Some scientists are tying those “ridiculously resilient ridges” to changes driven by melting sea ice in the Arctic.
“Unfortunately, the later and later extent of the fire season into autumn is something we are going to have to cope with,” Swain said. “We are already starting to see it. We didn’t really get major wildfires into November and December before, but we are now. This really is a new thing.”
