Rising Seas, Subsidence, and Our Crumbling Shores

Via Earth Island, a report on rising seas, subsidence, and our crumbling shores:

THIS SPRING, I found myself on a nature run in Junipero Serra Park, in San Bruno, a small town on the peninsula south of San Francisco. The park is a leafy-green oasis amid a crowded, affluent part of the Bay Area: shaded by coastal live oaks and Monterey pines, home to acorn woodpeckers, black-tailed deer, and, apparently, the occasional mountain lion who wanders out of the Santa Cruz Mountains.

Earlier that day, I’d heard a news report that heavy storms and ensuing floods had washed out a portion of California Highway 1 leading to Big Sur, an iconic locale on the misty cliffs of the coast. Two lanes had partially collapsed, leaving a single lane undamaged but adding to closure woes from landslides of years past. The president of the Big Sur Chamber of Commerce told the San Francisco Chronicle that losses from the slide would amount to a million dollars a day. The news was a tough reminder of the ongoing erosion of the California coast, unremarkable on its own, but evidence too of an unstoppable, unrelenting force, of things adding up.

The disappearing coast is a slow story, too slow to properly deal with.

I followed the trail to the top of a hillside covered in miner’s lettuce, where an opening in the trees offered a view of San Francisco International Airport (SFO), its runway just 10 feet or so above sea level. I stopped to take in the view — wondering, as I often do in the woods, how long humans can make a go of it. From up here, SFO looked like a model, a fragile airport in miniature, where miniature planes alighted, one after the other, in a constant, perpetual stream. How long, I wondered, will that airport remain? How long before the salt marsh returns, before this hilltop overlooks a ruin? From this vantage, I could easily imagine its destruction — and less so its salvation.

The United Sates is a coastal nation, though we don’t often think of it this way. Nearly 40 percent of US residents — about 130 million people — live along the coasts. Added together, the economies of coastal counties would rank third in the world for gross domestic product, behind only the entire US and China.

Much like drought, the disappearing coast is a slow story, too slow to properly deal with. It lives in the category of things that don’t demand immediate attention. There are always more urgent needs — raging wildfires, razed towns, floods that sweep homes and cars away. Crime, politics, jobs. Taxes, kids, love, heartbreak. And yet, for the past few months, as I’ve been traveling the California coast, I see the effects of erosion everywhere I go. They are small, sure, but they are everywhere, lapping at the edges of the continent: trails that have fallen apart, cliffs that have collapsed, beaches gone, asphalt disappeared. In their place come signs of resignation. “Detour,” “Road Closed,” “Do Not Enter.” These things are a nuisance, but they do add up. They cost us.

San Francisco Airport, for example, the seventh busiest in the nation, is sinking, even as sea levels rise. Geographers estimate it’s subsiding 0.38 inches per year, enough to warrant concern. By 2100, seas could rise here as much as 3.4 feet. The airport has a plan, the Shoreline Protection Program, through which it hopes to protect itself from flooding, storm surges, and rising seas. The plan entails concrete walls and steel sheets, along with rip rap to break up the waves, across eight miles of airport shoreline. This will cost $590 million. That’s just one airport. And only eight miles of shoreline. Not far from the airport, San Francisco has been forced to deal with an eroding coastal Great Highway, which is washed over with sand and will be closed by 2026. Just south of that lies a huge dune park called Fort Funston — a war-time and Cold-War gun and missile emplacement, now an off-leash dog park and launch site for hang gliders — which is itself falling into the sea. Farther down the coast, south of Los Angeles, San Onofre, an iconic state beach, has washed out, and desperately needs more sand. And cliffs up and down the state are collapsing. A 2022 study noted major cliff collapses in places like Palos Verdes, Los Angeles, as well as Big Sur, Martins Beach of San Francisco, and sites along the northern “Lost Coast”— up to 16 feet per year of losses.

Everywhere you look, the edge of the world seems crumbling to bits.

Bigger changes are not far off. A recent study in Nature estimates sea level rise for US coastlines of up to a full foot by 2050, “increasing the probability of more destructive flooding and inundation of major cities.” That doesn’t even take into account subsidence. When that’s added in, the researchers say, up to 536 square miles of US coastal land is under threat — and so are up to 273,000 people and their properties.

“Will cities be proactive and prepared through detailed assessment, planning and implementation of adaptive measures,” the authors ask, “or will they be reactive to events, waiting for these impacts and risks to manifest?” The authors cite their concerns, “given the inevitable continued rise in sea level beyond 2050 and its likely acceleration with further warming.”

Unlike other, more immediate threats, the power of erosion comes from its relentlessness.

It is the “inevitable continued rise” that nags. Unlike other, more immediate threats, the power of erosion comes from its relentlessness. Water always wins. The ocean is relentless, turning mountains into sand. But as hard as this is to imagine, as hard as it is to reach our minds into deep time — it is just as hard to imagine our way to a better future.

Or is it?

Perhaps we are still stuck in a post-pandemic malaise. The events of the last few years, added together, have made it hard to imagine a hopeful future. And yet, we must. And while it is difficult for someone like me, a simple ocean lover with no real expertise on coastal management, to see a way through, thankfully, others are doing the work.

Since 2021, for example, an initiative called the Envision Resilience Challenge has put academics, students, planners, architects, and others together to think through coastal inundation. The challenge has created potential new ways of living with the coast in Nantucket, New Bedford, and Fairhaven in Massachusetts, and Rhode Island’s Narragansett Bay. This year they’ll design around Portland, Maine.

The challenge prompts design ideas that come from students from various universities, and in them, one can see hope and inspiration. In them, we find walkable cities, festooned with bioswales and catchments, buffered by sand dunes and native grasses, with buildings on stilts and raised walkways over natural marshes, and navigable canals that move people, goods, and water. In this future coastal United States, economies are built around sustainable oceans, offshore kelp, and oyster beds protected by breakwaters and pilings.

These ideas are not exclusive to the East Coast. In Los Angeles, a desert city in disguise, architects have thought hard about how to mitigate the impact of increased flooding of the Los Angeles River and other waterways, as climate change alters the hydrological cycle. Some imagine of city of “sponge houses” and “bladder houses,” designed to catch water, filter it, and cycle it back into homes. Such measures don’t address rising seas head on, but they do point to a future of coastal living that has adapted to change.

This is the key, I think. Designing for the inevitable. Design over despair. When we see ourselves outside of nature, it can be easy to see nature overwhelming the human experiment. But if we see ourselves as part of nature, we can see how we might stop fighting and start cooperating. The language shifts from that of war — of fighting climate change, or retreating from the sea — into something more creative. Humans need not be destructors, and we need not give in to narratives of destruction. We can build, repair, regenerate. We can, and must, reimagine our world.



This entry was posted on Wednesday, July 10th, 2024 at 9:37 pm and is filed under Sea Level Rise, Subsidence.  You can follow any responses to this entry through the RSS 2.0 feed.  Both comments and pings are currently closed. 

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Black Swans / Green Shoots examines the collision between urbanization and resource scarcity in a world affected by climate change, identifying opportunities to build sustainable cities and resilient infrastructure through the use of revolutionary capital, increased awareness, innovative technologies, and smart design to make a difference in the face of global and local climate perils.

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