When a raindrop falls in San Francisco, it has two choices: flow east into the San Francisco Bay, or west into the Pacific Ocean. A ridgeline divides the city into two, slicing through the Presidio, hugging the eastern edge of Golden Gate Park, and skirting Twin Peaks. As the land drops off in either direction, the elevation difference doesn’t just drive raindrops downhill—it also moves human waste. San Francisco, unlike any other coastal city in California, has just one set of pipes for its storm runoff and sewage. First engineered more than a hundred years ago, the system still functions on the same basic principle as it did in 1890: Let gravity do the work.
But the city’s early engineers didn’t account for the eight inches of sea level rise the bay has seen over the last century. And they certainly didn’t foresee the additional five feet expected by the end of the next hundred years, which promise to cause major flooding—not to mention a serious poop problem. Engineering a solution to the rising tides will be enormously expensive. Which is why the city thinks someone else should pay for it. Like, say, Big Petroleum.
Last month San Francisco announced it was suing the five largest publicly-held producers of fossil fuels in the world. The lawsuit aims to make these companies pay for the miles of seawall construction and sewer system redesigns required to protect the city from climate change. Climate change caused in part by all the fossil fuels they sucked, mined, and fracked out of the Earth. It may sound like a long shot, but the case rests on one of the oldest and best-tested environmental laws on the books, the same one that brought down Big Tobacco in the ‘90s and Big Lead Paint in the aughts. Whether or not the same rules apply to the threat of climate change is a question with implications far beyond the sewers of San Francisco.
But for now, let’s start there. When Carl Edward Grunsky, a German-born geologist and civil engineer arrived in San Francisco in the 1890s, his sense of order was offended nearly as much as his nose. For nearly 40 years people had been laying brick sewers willy nilly. The result was a city that “smells to Heaven with a loudness and persistence that the strongest nostrils may not withstand and the disinfectants of a metropolis could not remove,” as one health official at the time declared. Grunsky developed plans for an innovative gravity-based sewer system that would drain rainwater-diluted waste all the way from Daly City to North Point, where the rapid current would sweep it out to the Golden Gate.
At the time, it was a great leap forward in sanitation, even though it overflowed during rainstorms and dumped raw sewage into the bay. By the 1970s, with the passing of the Clean Water Act, that was a no-no. So the city built a ring of giant underground chambers around the peninsula—some as big as 25 feet wide by 45 feet tall. During dry weather, sewage collects at one of two treatment plants. But when it rains, storm runoff and sewage run downhill through a single set of pipes and drain into the big chambers. They function like waiting rooms, detaining stormwater until the treatment plants can process it all.
Today, overflow only happens during big storms, when the chambers and treatment stations fill to capacity. Then, sewage and stormwater have nowhere to go but out of 36 discharge outfalls located around the city, several feet below street elevation. But if especially wet weather happens to coincide with peak high tides, those outfalls become submerged, flooding any areas of the city at or below bay level with a mix of sewage and stormwater. This has been happening more frequently lately, as climate change has already raised sea levels around San Francisco by a few inches. And it’s expected to happen a lot more in the coming decades, with levels estimated to increase by up to 24 inches by 2050—enough to put most outfalls underwater daily.
Rising seas aren’t just a problem during the rainy season. In dry weather, big tides can breach the outfalls, flow into the collection containers, and wind up in the treatment plants. Corrosive saltwater wreaks havoc on the pumps, filters, and other equipment keeping San Franciscans from living in a cesspool. Today, that happens fairly infrequently. But more ocean means more ocean water entering and damaging the system.
A backseat engineer might ask at this point, “Why not just raise the outfalls a few feet?”
Oh, were it only so simple. But because the sewers are built on the city’s existing gravity-driven hydraulic gradient, you can’t go tweaking one part without feeling the effects system-wide. Higher outfalls won’t get submerged as often, but during storm events there will be less room for all that water to go. Which would mean even more flooding during the rainy season, even with the outfalls clear of the tides. And, don’t forget, those outfalls lead to containers and treatment plants that are mostly all underground, directly in the path of shoreline erosion caused by rising sea levels.
Without upgrades, here’s what will be inundated by the end of the century: SFO International Airport, the Giants Stadium, the site of the new Warriors Stadium. And, oh yeah, headquarters for companies like Facebook, Google, Airbnb, and the brand-spanking new Salesforce building, now the skyline’s tallest spire. Models project 6 percent of San Francisco will be inundated by normal, daily tides by 2100.
Last year San Francisco Mayor Ed Lee committed an initial $8 million to begin fortifying the city’s seawall. But shoring it up in the short-term will cost about $500 million—long-term, $5 billion. Add to that another $350 million to protect all the wastewater infrastructure and limit how much seawater makes it inside, and the climate change costs quickly add up. Costs, the city now says, should be shouldered by the corporations that still produce vast quantities of fossil fuels, despite having known for decades their role in driving climate change and accelerated sea level rise.
“These fossil fuel companies profited handsomely for decades while knowing they were putting the fate of our cities at risk,” San Francisco City Attorney Dennis Herrera said at a press conference announcing the lawsuit in September, which named BP, Chevron, ConocoPhillips, Exxon Mobil, and Royal Dutch Shell as defendants. “Now, the bill has come due.”
Oakland filed a similar lawsuit on the same day, with both cities charging the companies with liability for public nuisance, failure to warn, trespass, and negligence. They’re seeking only the funds needed to adapt infrastructure against encroaching seas. The cases represent the first real legal test of whether or not climate change blame is not only assignable, but quantifiable.
If they can get in front of a judge. To date, every attempt to bring a case based on a climate change-related injury has either been dismissed for lack of standing, lack of jurisdiction, or both. That’s because, while the courts were willing to entertain the complex causal chains linking secondhand cigarette smoke to cancer and lead house paint to behavioral and developmental issues in children, they so far have viewed climate change as so enormously complicated as to be outside the scope of adjudication. “I told you before I’m not a scientist,” former Justice Antonin Scalia told the Supreme Court in 2007. “That’s why I don’t want to have to deal with global warming, to tell you the truth.”
But many legal experts say pressure (and scientific evidence) is mounting to let climate change have its day in court. “There’s certainly a sense that climate change is broader in scope than what nuisance law has ever addressed before,” says Sean Hecht, co-executive director of the UCLA law school’s Emmett Institute on Climate Change and the Environment. “But it couldn’t be that if the nuisance gets bigger and bigger that courts are less and less likely to impose a remedy. That flies in the face of reason.”
While it’s too early to say whether the court will be willing to look at San Francisco’s case, Hecht says it’s a strong one. The injury to the city is discrete, with sea level rise being the most well-established downstream effect of climate change. California, more so than any other state, has devoted serious resources to gathering data, modeling, and understanding the impacts of sea level rise on its shores. And the fossil fuel industry’s knowledge of the problem even as they sowed a public misinformation campaign has become increasingly well-documented. Any sort of victory, no matter how small, could embolden other local governments to sue oil and gas companies for host of other climate change-related expenses—like, say, super-soaking hurricanes or drought-fueled megawildfires.
Which is why San Francisco’s case is about more than just sewers and seawalls. It’s about who pays for climate change: the people hit hardest by it, or the corporations who profit from it? Like a raindrop falling on the city, there are only two ways forward. And every year the path to the ocean gets a little shorter.