“No such thing as the new normal,” California fires larger and more severe than ever

Late Wednesday night, PG&E de-energized power lines in the North and East Bay to reduce the risk of wildfires amid high winds and dry weather, cutting power to over 32,000 Alameda County residents. Soon after parts of the grid went dark, a Diablo wind began blowing in from the northeast. Bone-dry air swept down from the Sierra Nevada mountains, gusted across the peaks of the North Bay at 77 miles per hour, and raced down into the valleys. Earlier in the afternoon, relative humidity at the Sonoma County Airport fell to just 3 percent. “It doesn’t get much drier than this in the Bay Area,” tweeted the National Weather Service. Perfect fire weather. 

Over the last two decades, climate change has made California hotter and drier, leading to more explosive wildfires and a longer fire season. “Wildfire is a natural and necessary part of many ecosystems—forests and grasslands,” says Dr. Patrick Gonzalez, a climate change scientist and forest ecologist at UC Berkeley and a lead author for the Intergovernmental Panel on Climate Change. But over the past few years, he says, fires have gotten larger and more severe due to outdated forest management policies and the effects of climate change.

For much of the last century, the federal and state governments have extinguished wildfires as quickly as possible, which has created an unnatural buildup of fuel on the forest floor. Mid-elevation conifer forests in California, like many parts of the Sierra Nevada range, have a natural fire frequency of twelve to fifteen years. When small, natural wildfires do not clear out young trees and wood debris on the ground, the fuel builds until it can feed a much larger fire.

Adding to the problem, climate change has increased temperatures across the state, leading to more arid conditions, decreased summer rainfall, and a longer fire season. “These old policies piled up the fuel, and climate change threw in the match,” said Gonzalez. And the fires are only going to get worse. California’s Fourth Climate Change Assessment, published in January, 2019, predicts that by the end of the century wildfires will burn 77 percent more land, although they could burn as much as 178 percent more land based on some models.

Climate change is already affecting Bay Area residents in tangible ways. “While we are reducing emissions, we have to—at the same time—deal with reality, which is more hot days, more extreme temperatures, more conditions for wildfires, and probably more wildfires,” says Bruce Riordan, director of the Climate Readiness Institute at UC Berkeley. He adds that events like the catastrophic wildfires of the past two years have helped increase awareness about climate change, but at a tragic cost.

Yvette Sapp, 62, has lived in Oakland her entire life. Her home, which is right below the Oakland Zoo, lost power at 11:42 pm on Wednesday night. On Thursday afternoon, she visited the PG&E Merritt College community resource center along with a handful of other local residents to charge her cellphone. “I remember this kind of wind happening during the Oakland firestorm,” says Sapp, as the white plastic tent flaps loudly. On October 20, 1991, Diablo winds similar what the Bay Area experienced last week propelled a massive conflagration that burned structures in Montclair, Upper Rockridge, and the edge of Piedmont and claimed 25 lives. Sapp recalls walking outside her home that day and seeing the sky grow dark as ash fell.

Over the years, Sapp has noticed higher temperatures earlier in the summer and drier conditions. As for the fires, “They’re more out of control, they’re bigger, they’re deadlier,” she says. “It was never as intense as it is now.” Like a growing percentage of Californians, Sapp attributes these shifts to climate change. A September 2018 poll conducted by the Public Policy Institute of California found that 67 percent of Californians understand that the effects of climate change have already begun.

The rising temperatures, more frequent red flag warnings, and PG&E power shutoffs have prompted many to ask: Is this the new normal? Dr. A. LeRoy Westerling, a professor of management of complex systems at UC Merced, hates that phrase: the new normal. “This is exactly the opposite of a new normal,” he says.

In the past, scientists could look to historical climate data to understand risks. Since the climate was stable, they could assume that future events—like how long a drought would last, how much rain would fall, or how long a fire season would last—would fall within the same parameters that they had in the past. But now, by releasing massive quantities of greenhouse gases into the atmosphere, humans are changing the environment profoundly. This is not just a matter of adjusting the parameters and settling on new normal. As the planet warms, the parameters are constantly changing, and will continue to change. “We’re shifting the climate system. No one alive today will ever experience a stable climate system again,” says Westerling. 

Scientists know that hotter, drier weather will lead to more frequent, more intense wildfires. California can mitigate the risks by adopting smarter forest management policies, like prescribed burns and the removal of fuel sources, but residents will still experience extreme fire risk weather more often, and the fire season will typically last longer each year. Even as communities like Oakland work to reduce greenhouse gas emissions to limit warming, residents should brace for more public safety power shutoffs during hot, dry, windy days as PG&E continues to update its infrastructure, an increase in large wildfires, and a greater number of days of poor air quality due to wildfire smoke. This is only the beginning.