California is basically one gigantic accident. As it currently looks, the landscape would be unrecognizable to the indigenous peoples who lived here before the Spaniards arrived, and not just because of our Tuscan-looking vineyards and secluded cannabis compounds. Statewide, our grasses are non-native, almost to a blade. In San Francisco, eucalyptus forests like the one that protects Cole Valley from the wind, the knobby London plane trees opposite City Hall, the nasturtiums that cover Stern Grove, the yellow Scotch broom lining Highway 1 – all of it was introduced, often very stupidly, by misguided humans – the compounding of a thousand small errors.
The Golden State has always been in flux, and climate change from greenhouse gases is just another phase, although a scarier one. Since exotics have been taking advantage of California’s fertility for well over a century, it’s against the background noise of this endless colonization that San Francisco’s anxiety usually turns to that other source of major agita: the Pacific, which is very slowly coming to get us.
Geek blogger extraordinaire Burrito Justice’s San Francisco Archipelago depicts a 200-foot rise, contrasting recalcitrant NIMBYs of “Potrero Island” in 2072 with public works projects aiming to shore up a viable city, however futile the effort. It’s not likely to get so bad so quickly – the city is anticipating a four-foot rise by 2100; the Coastal Commission thinks it'll be more like three. Whether the waves lap against the submerged Victorian turrets off “Duboce Beach” or we just have to build a slightly higher seawall around Red’s Java House, there is still another reality to consider: the climate itself. And it’s pretty damn depressing.
To be brief, it’s going to be warmer and it’s going to be drier. Just how warm and how dry will no doubt be the subject of dissertations and symposia for years, while P.R. flacks from Chevron deny any of it is happening. Rainfall in SF is erratic year to year (and varies widely within the city) but these last two winters, the driest back-to-back years since the early 1990s, averaged barely two-thirds of the 23 inches we usually get. And what rain we do get will likely fall in heavier storms, rather than drizzle. Additionally, the Sierra snowpack will shrink considerably by midcentury, most likely by a quarter. The EPA’s best guess is that the temperature in 2100 will be higher by between four degrees Fahrenheit (which will be painful) and eight (which may mean a totally different planet). What will this new reality mean for the Bay Area’s iconic flora?
The first things that come to mind are the coast redwoods, the highly vulnerable giants that barely survived extensive logging and the invasive species humans schlepped in, such that they inhabit only 5 percent of 2.1 million acres they covered in 1850. Fog-dependent and slow to mature, these majestic trees will have a difficult time surviving rapid climate alterations, as they’ll probably never be able to migrate north fast enough to keep up. (And even then, a Redwoods National Park with all the redwoods outside the boundaries is depressing.) Although these trees are resistant to fires, our overzealous fire suppression policy plus the likelihood of major conflagrations in a hotter state mean whole groves could be devastated quickly. What’s especially unfortunate is that redwoods are tremendous weapons in the fight, sequestering more carbon dioxide per hectare than even the Amazonian rainforest. Muir Woods may look a lot less like the Forest Moon of Endor from Return of the Jedi, and soon.
It doesn’t look pretty for the two remaining wild populations of Monterey cypress, either. Along with their precursors, this and related species such as the smaller and equally rare Gowen cypress have been around for 200 million years, but their discontinuous distribution up and down the coast implies that their bright green leaves have been dwindling for a long time. Habitat restriction and low numbers mean that the famous Monterey cypress groves at Point Lobos are quite fragile. Even slight disruptions to the climate could lead to their disappearance from nature, although they won’t likely go extinct altogether.
Closer to home, Golden Gate Park’s Rhododendron Dell is not likely to thrive. Fussy rhodies love damp and shade (which they don’t really get), and dislike wind and salt air (which they do). According to a high-ranking gardener for Rec and Parks, the plants were originally lifted and rotated a quarter-turn every year so as to make them grow evenly, and the dell even retained its own staff of three full-time gardeners as recently as the 1960s. (Currently, it has but a single half-timer.) Absent major philanthropy or a corps of volunteers to restoretheRhododendron Dell to its former glory, it relies on a few cultivars that can tolerate the weather. If those conditions change in the direction predicted, the celebrated Rhody Dell, a gay cruising spot in its heyday, will be relegated to a grim survival of the fittest.
It’s not all doom and gloom, however. Quite literally, San Francisco may be less gloomy since a drier climate prevents fog formation. Then again, an alternate hypothesis predicts that a hotter Central Valley will suck in oceanic air more intensely, actually making the Bay even foggier than it is already. But either way, there are a number of species that may flourish in the future climate.
Bougainvillea will do better. They’re happier where it’s warmer and a trip to Los Angeles or San Diego reveals just how full and lush these babies can get. The same goes for roses, avocadoes, and figs. We’ll get a wider variety of palms, and more tomatoes other than Early Girls.
The jacaranda will thrive. As San Francisco sits just north of the boundary where these puppies do best, we could eventually see some serious twice-yearly purple blooms. Jacarandas already carpet many temperate world cities far outside their native Central America, so San Francisco could look more like L.A., Sydney, Buenos Aires, or Pretoria.
Among commercial crops, grapes are a bellwether. As growing regions shift north, upslope and toward the coast, varietals such as Chardonnay and pinot noir that require cool breezes may feel the squeeze, assuming scientists can’t hybridize them to make do with less “hang time” on the vine. American Viticultural Areas will probably have to be redrawn, no doubt to some controversy. It’s entirely possible that San Francisco may one day be hospitable to small-scale artisanal viticulture while Napa simply withers away. One thing that does not grow here and probably never will is corn, which requires serious, sustained heat. However, corn is, like, way Middle American anyway, as one sip of Mexican Coke will tell you. This just ain’t a high-fructose kind of town.
The happiest story may be that of the Franciscan manzanita. Growing here and nowhere else, it was considered extinct for over 60 years until the Doyle Drive construction project exposed a single plant growing in the Presidio. It was subsequently moved for its own safety – see pics of the undertaking here– and botanical institutions successfully propagated some cuttings. Somewhat ironically, what protected the Franciscan from being out-hustled by invasive competitors was its love of serpentine, a highly alkaline soil condition toxic to many other plants, including most manzanitas. (Serpentine is that green rock seen under the Mint, but it’s the larger outcropping in the Presidio that supports native vegetation.) Once thought lost, and in spite of being added to the Endangered Species List in 2012, the fragile Franciscan manzanita is actually poised to handle climate change fairly well.
Ultimately, the more cosmic the time scale, the more you realize that San Francisco is quite temporary. Even if Homo sapiens become a race of perfect hippies who live in balance with the earth, we’ll never be able to stop future earthquakes or prevent California’s collision with the Aleutian Islands in 24 million years. But there’s a massive difference between taking a Zen approach to our ultimate impermanence and ignoring the effects of human tomfoolery during our lifetimes. Pick your favorite kind of tree and think of it like a giant panda, a symbol too special even to conceive of a world without it.
This story is part of The Bold Italic's Facing Change package. Read more about the series here.