What the National Climate Assessment Means for the Bay Area

There’s not much to surprise you about what climate change means for Northern California in the National Climate Assessment Report, released by the federal government the day after Thanksgiving. Just page upon page of clinical, detailed, authoritatively sourced reporting to show that absent massive and immediate emissions drawdowns, life here in the next few decades will not be anything like it once was.

There’s not much to surprise, in part, because if you’ve been living in California for the last few years, you’ve already lived the vanguard of the change. The country’s hottest, driest region is getting hotter and drier (except at the immediate coast), and the droughts and heat waves we’ve seen in the last few years will only grow more common on our current emissions path as temperatures rise by another 8.6 degrees Fahrenheit by 2100. Mountain snow is decreasing, with some years like 2015 bringing almost no snow at all, and by 2050 many parts of the Sierra Nevada could see only rain. The ocean is warming, acidifying, and losing oxygen, and the die-offs, fishery failures, and algal blooms of the last four years will only grow more common. The sea level at the Golden Gate rose 9 inches between 1854 and 2016; if we keep upping our emissions as we are now it could rise another 30 inches in half that time. We spent two weeks in November sheltering kids indoors from the out-of-control smoke of the state’s worst-ever wildfire, and watched the air quality site AirNow.gov crash because too many people were using it. That, too, will only grow more common.

More than 300 experts contributed to this fourth national state-of-the-science report, which by law the U.S. Global Change Research Program prepares every four years, and which was immediately dismissed by President Trump, who told reporters, “I don’t believe it.” The report examines nationwide topics and then breaks into regional assessments, with California grouped along with Nevada, Utah, Colorado, New Mexico, and Arizona in a chapter on the American Southwest.

Collectively the assessment paints a picture of states, regions, and individuals surrounded by leaf-covered rakes, continually stepping on the next one and getting slammed in the face—whap! —as climate change accelerates. “It just seems like there’s some thresholds we’re close to, and maybe we didn’t realize we were so close to, and we crossed a bunch of them in the last four years in particular,” says Nate Mantua, a physical scientist at the NOAA Southwest Fisheries Science Center who contributed to the ocean science section of the report.

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Many of the individual climate change consequences we’ve known about seem to cause other, unanticipated effects. A 2015 harmful algal bloom, caused in part by unprecedented warm water in the northeastern Pacific, delayed crab season into the peak of whale migration season, which then led to more whale entanglements in crab fishing gear. In the health realm, says report author and UC Davis Medical Center epidemiologist Dr. Helene Margolis, fire season once ended before common cold season really picked up. But now particulate pollution and cold season overlap, with potential unanticipated health complications. And those are minor compared to heat waves moving into places like San Francisco where most homes don’t have air-conditioning or ozone pollution persisting for days in rural regions where it typically breaks down overnight.

“These are dire effects,” Margolis says. “They are ones that if we do not address head-on will be devastating both in terms of human health and well-being and economically. However, they are exposures and outcomes that we can in fact be prepared to address if we invest the resources and with adequate planning. We can do a lot to protect ourselves.”

Margolis says people can do much of what conservation scientists have advocated on behalf of wildlife: remove any other stressors that you can control, so that you face the ones you can’t control when you’re at peak strength. Increased heat and air pollution stress will most affect the health of people who already suffer other health problems or have weakened immune systems, Margolis says, which means that one of the greatest climate adaptation priorities is to improve community health.

Among the most vulnerable people in the Southwest, the report says, are Native Americans. The region has the nation’s largest population of Indigenous people, and climate change is driving scarcity in staple food crops and culturally significant plants and animals, and putting increased pressure on land and water resources. One solution, says report author and UC Davis Native American Studies professor Beth Rose Middleton, is to secure and increase tribal jurisdiction over land. That’s a challenging proposition in areas where many Ohlone groups still struggle for basic recognition. But she notes that focusing on tribal land could also have powerful positive effects, from long-term tribal studies of environmental change to forward-thinking management and adaptation plans.

Of course, bigger picture, when you’re surrounded by rakes, the answer is not to keep running in new directions hoping to avoid them. The answer is to clean up the rakes.

“We have to get serious about putting the brakes on climate change and ocean acidification,” Mantua says. “The kind of climate change and acidification projected for later this century dwarfs what we just experienced. That means it’s going to make it really hard to come up with ways to minimize the impacts. That’s not a future I think we want to have to deal with.”