California’s recent temperatures have crushed decades-long records, reaching 120 degrees Fahrenheit in Chino and 111 degrees in LA last month alone.
While the temperatures may have stunned residents, there’s one group that isn’t surprised: climate scientists predicted everything from the blistering heat and blazing fires to the state’s massive power outages more than a decade ago. In recent years, they say, we’ve seen a climate that’s a harbinger of what’s to come for California: an increasingly volatile landscape ridden with worsening floods and wildfires, like the recent Carr fire that destroyed and damaged more than 1,000 homes.
“The trends that we’re seeing — and the predictions that were made — were called three decades ago,” says Noah Diffenbaugh, a Stanford University geoscientist. He adds that expert predictions for the future suggest that the climate extremes of California’s past five or six years are “indicative of what the future will hold.”
In the past few years, California has seen fires that are unprecedented in both scope and the damage they bring. In July, more than 1,000 wildfires were sparked over a one-week period, which is more than three times the number experienced in decades past, according to the California Department of Forestry and Fire Protection (Cal Fire). Not only that, but compared to this time last year, we’ve seen more than 70,000 additional acres of the state burned, the agency says.
These recent fires are also a different breed from the ones that have hit the state in the past, according to experts. Traditionally, dry, blustery winds known as the Santa Anas, or “Diablo winds,” breeze through Southern California from October to March. This is colloquially known as the “fire season.” Local plants are dried into kindling this time of year, and any fires — caused by anything from stray cigarette butts to lightning to arson — are easily carried and spread by the high winds. But what used to be a fire “season” is now a year-round risk, and it will only get worse with a warming climate, says Diffenbaugh.
“Fire requires a few factors to come together. There’s never been a wildfire without ignition, but how much fuel there is, how dry it is — all of that matters for fire risk,” he adds.
Recently, there has been a lot more fuel. In 2017, a wet winter season allowed native wildflowers and invasive weeds to flourish in what some called a “super bloom.” When the climate turned arid during California’s hottest summer on record, all of this new growth turned into crackling tinder. That year, more than a dozen deadly wildfires scorched Northern California, killing at least 40 people. This year’s winter, meanwhile, was unseasonably dry. So while we didn’t see these super blooms, we did see plants on the ground — like grass, brush, and millions of dead trees — get turned into ideal fire fuel that spread embers at explosive rates. And with warm, arid conditions in the spring arriving earlier and earlier, it’s a recipe for fires that burn farther, longer, and well into spring.
It’s not hard to imagine that as these fires get worse, more houses will burn and more people will be injured. But these worsening trends aren’t stopping developers from building new homes directly in some at-risk areas.
“There are certainly a lot more people in harm’s way now than there were 10 years ago. And 10 years ago, there were more than there were in the previous decade. So we’ve certainly been moving more people into harm’s way,” says Daniel Swain, an environmental scientist at UCLA. “And while the conversation might be shifting, there are still a lot of urban areas that border on land with a large fire risk.”
Climate change isn’t only making fires worse, it’s also increasing flooding risk. Warming winter temperatures have caused more of California’s winters to be full of rain rather than snow, leading the more than 1,000 dams that the state uses to store water, generate power, and stave off potential floods to fill more quickly. Because most of these dams were built more than four decades ago, they aren’t prepared for the deluges that happen during the winter months. This, according to experts, means that floods, like the one that we saw at the Oroville Dam in February 2017, could be a lot more common in the years to come.
Paradoxically, the rising risk of floods also means there’s a greater risk of water shortages. The officials overseeing the country’s reservoirs are pressured to release that water earlier in the year because of the impending flood risk, says Diffenbaugh. As these dams face the pressure to stave off a potential flood, that means the towns that these reservoirs feed into will have less water available during the summer.
A lot of these changes are coming soon for Californians, regardless of how we change our emissions trajectory, according to Swain. The reason, he says, is because CO2, the biggest greenhouse gas, stays in the atmosphere for decades or longer. So even if we sharply decrease the amount of carbon dioxide we’re emitting, many of these changes are locked into the climate system for years to come. And with the United States pulling out of the Paris climate agreement, there are few signs that the world is about to sharply cut emissions, which is locking in even worse changes for the future. Last year, in fact, carbon emissions reached a record high, as did methane, another greenhouse gas.
“We can’t suddenly make the kind of radical change in the global carbon economy that we’d have to make to get to carbon zero,” Swain says. “It’s not going to happen over the course of a few years.”
What we’re deciding now, he says, isn’t the climate for the next few decades. We already know that’s going to heat up. But we do have the power to change what our climate will look like during the second half of the century, according to Swain. Those changes could be radical or they can be modest, depending on how much carbon we burn, but the extent of the heating is up to us.
“Even though there’s definitely going to be more warming, there’s a wide range about what ‘more warming’ means,” he says. “Is it another degree, or is it another four degrees? That’s a massively different world.”