La côte californienne a grandi et prospéré pendant un moment remarquable de l'histoire où la mer était à son plus bas.

Mais le puissant Pacifique, à l'insu de tous, approchait des dernières années d'un cycle calme mais inhabituel qui avait bercé les colons rêveurs dans un faux sentiment d'été sans fin.

Autre part, Miami s'est noyée, La Louisiane rétrécit, Les plages de Caroline du Nord disparaissent comme un laps de temps sans fin. Alors que d'autres régions étaient aux prises avec des vagues destructrices et des mers montantes, la côte ouest a été épargnée pendant des décennies par une rare confluence de vents favorables et d'eau plus fraîche. Cette « suppression de l'élévation du niveau de la mer, " comme l'appellent les scientifiques, est passé largement inaperçu. Aveuglé par les conséquences d'un réchauffement de la planète, Les Californiens ont continué à construire jusqu'au bord de l'eau.

Mais les lignes dans le sable sont censées se déplacer. Au cours des 100 dernières années, la mer a monté de moins de 9 pouces en Californie. A la fin de ce siècle, la surtension pourrait être supérieure à 9 pieds.

Les feux de forêt et la sécheresse dominent les débats sur le changement climatique dans l'État. Pourtant, cette réalité dont on parle moins a acculé la Californie. Le littoral s'érode à chaque marée et tempête, mais tout s'est construit avant que nous ne sachions mieux — Pacific Coast Highway, des maisons de plusieurs millions de dollars à Malibu, la ligne de chemin de fer à San Diego est fixée en place avec nulle part où aller.

Mais le monde devient plus chaud, les grandes calottes glaciaires encore en train de fondre, la montée de l'océan un désastre lent qui a déjà balayé la porte d'entrée de la Californie. Les falaises du bord de mer s'effondrent à Pacifica, abattre des immeubles entiers. l'île de Balboa, à peine au-dessus du niveau de la mer, dépense 1,8 million de dollars pour élever le mur qui le sépare de l'océan.

Les tempêtes hivernales ont frappé une promenade de la plage de Capistrano, transformant le rivage idyllique en zone de construction alors que les bulldozers se précipitaient pour empiler des rochers dans une barricade. De San Diego aux comtés de Humboldt, les propriétaires se démènent pour repousser l'érosion croissante et les ondes de tempête, plaider auprès des autorités pour des digues plus grandes qui peuvent retenir l'océan encore plus grand.

Il y a tellement de façons de jouer contre la montée des eaux. Les digues sont une option, mais ils ont un coût caché :forcer le sable devant eux à disparaître. Pour chaque nouvelle digue protégeant une maison ou une route, une plage pour le peuple est sacrifiée.

Ajouter du sable aux plages en voie de disparition est une autre tactique, mais cette course contre nature ne dure que tant qu'il y a de l'argent et assez de sable.

Ensuite, il y a ce que les scientifiques, les économistes et les consultants en calcul numérique appellent une « retraite gérée » :déménager, essentiellement céder la terre à la nature. Ces mots seuls ont troublé les quelques villes assez hardies pour les prononcer. Les maires ont été évincés, documents de planification réécrits, campagnes menées sur l'idée même de transformer des biens immobiliers de premier ordre en dunes et en plages.

La retraite est aussi anti-américaine que possible, groupes de quartier déclarés. Gagner, La Californie doit défendre.

Mais à quel prix ? La Californie devrait-elle devenir un long mur de béton contre l'océan ? Y aura-t-il encore des plages de sable ou des spots de surf à chérir dans le futur, des maisons en bord de mer qui font rêver? Plus de 150 milliards de dollars de biens immobiliers pourraient être menacés d'inondation d'ici 2100, des dommages économiques bien plus dévastateurs que les pires tremblements de terre et incendies de forêt de l'État. Marais salants, abritant des oiseaux de rivage et des espèces menacées, face à l'extinction. Rien qu'en Californie du Sud, les deux tiers des plages pourraient disparaître.

L'État n'a pas le temps et trop de temps pour agir, en spirale dans des batailles paralysantes sur le pourquoi, qui, quand et comment. Il n'est pas trop tard pour que les Californiens montrent la voie et anticipent l'élévation du niveau de la mer, les experts disent, si seulement il y avait la volonté d'accepter la situation dans son ensemble.

De retour après des coulées de boue et des incendies de forêt. Reconstruction dans les zones inondables. L'envie humaine de surpasser la nature est séculaire. Nous nous moquons de la grenouille légendaire qui a bouilli à mort dans une casserole d'eau se réchauffant lentement, mais refusons d'affronter la réalité de la mer alors qu'elle s'enfonce plus profondément dans nos villes.

Nous avons tous joué près du rivage et construit des châteaux dans le sable, mais semblent oublier ce qui se passe ensuite :l'océan gagne toujours.

Pacifica—Une ville à la limite

Sur les falaises et les rivages de Pacifica, une étendue de carte postale de hameaux côtiers juste au sud de San Francisco, les résidents craignent que la planification de l'élévation du niveau de la mer signifie condamner leur propre communauté à l'extinction.

Ici, ce dont les autres villes de Californie commencent seulement à s'inquiéter dans l'abstrait est déjà une réalité bien vécue. De puissantes vagues déferlent sur la jetée principale et menacent les routes avec des noms tels que Beach Boulevard et Shoreview Avenue. Des explosions de sable battent les murs et les maisons. Des vitres éclatent. Les falaises s'effondrent. Les résidents témoignent de pans entiers de collines qui s'effondrent dans les vagues en contrebas.

Dans une partie de la ville, l'océan a rongé plus de 90 pieds de falaise en moins d'une décennie.

Les gens pouvaient marcher sur Pacifica comme une étendue de plage entière dans les années 1970, mais le rivage ouvert s'est rétréci au fil des ans alors que la ville construisait des digues, pierres entassées, enduit ses fragiles falaises de grès d'un béton spécial pour protéger ce que la nature prenait de force.

Aujourd'hui, la majeure partie de la côte de Pacifica est blindée. Mais même avec ces défenses, la ville devait encore racheter une rangée de maisons au sommet de la falaise, transformant plus tard la rue en sentier. Au bord du sable, d'autres maisons ont été enlevées et un parking public reconstruit à 50 pieds plus loin à l'intérieur des terres.

Le long du boulevard de la plage, des panneaux avertissent les promeneurs de chiens et les joggeurs que les vagues peuvent déferler sur la digue. La chaussée est souvent mouillée par les hautes vagues. Les voitures sont invitées à continuer de rouler. Les habitants sont assez sages pour ne pas s'attarder trop longtemps près de la jetée vieillissante.

Une femme qui l'a fait a été frappée en 2006 par une vague qui a soufflé dessus. Quand elle fut enfin capable de respirer et d'ouvrir les yeux, elle a été stupéfaite de découvrir qu'elle avait été emportée à l'arrière du garage de quelqu'un, son bras accroché à travers un barbecue.

Les chocs ont continué. Des années de sécheresse suivies de fortes tempêtes en 2016 ont forcé plus d'une douzaine de résidences au sommet d'une falaise à être étiquetées comme dangereuses. Trois immeubles d'habitation – soudain suspendus au bord – n'ont pas pu être sauvés et ont été démolis.

Répondre à cette dernière saison d'El Niño a coûté 16 millions de dollars à Pacifica, ce qui n'est pas un petit changement pour une ville dont le budget de fonctionnement de 36 millions de dollars repose principalement sur les impôts fonciers. Les responsables cherchent toujours des fonds pour couvrir les dommages de 2016 et restent embourbés dans une bataille de domaine éminente sur deux des bâtiments.

Pacifica est devenue cette histoire d'imprévus, retraite forcée, les experts disent, et le public s'est retrouvé coincé avec le projet de loi.

"Il y a un coût public et un coût privé dans tout choix que nous faisons, et nous devons commencer à faire cette analyse coûts-avantages, " dit Charles Lester, directeur de l'Ocean and Coastal Policy Center de l'UC Santa Barbara, qui a consulté pour plusieurs villes, dont Pacifica, sur la planification de l'élévation du niveau de la mer. "Si nous ne commençons pas à gérer la retraite maintenant, combien cela va-t-il coûter plus tard ?"

Dans des centaines de pages de documents de planification, les responsables ont conclu que déménager à l'intérieur des terres dans les décennies à venir pourrait être l'option la plus rentable pour un certain nombre de quartiers. Les digues continuent à échouer, ils ont dit, et l'océan gagne. Une grande partie de la protection du rivage pourrait être dépassée par une élévation du niveau de la mer d'à peine 1 pied.

Mais beaucoup ont fustigé la proposition, déclenchée par une campagne sur les droits de propriété menée par le secteur immobilier. Les propriétaires ont inondé les réunions de la ville, frappé aux portes des voisins et placardé des pancartes en ville. Le maire est devenu le punching-ball de la ville, et de nouveaux dirigeants ont été élus pour aider Pacifica à tenir bon.

"'Retraite gérée' est le mot de code pour abandonner - sur nos maisons et la ville elle-même, " a déclaré Mark Stechbart, qui s'inquiète que Pacifica, et à son tour la valeur de sa propre maison, sera licencié par les futurs développeurs, assureurs et acheteurs. "Ce n'est pas juste un exercice intellectuel. Ce sont de vraies personnes et une vraie ville en jeu."

Pour Suzanne Drake, un bénévole de la société historique qui a concocté assez d'argent pendant la récession pour acheter "la maison la plus moche de la plus belle rue de la ville, " parler de retraite gérée a suscité une colère qu'elle ne savait pas qu'elle avait.

Les mots sont comme une lettre écarlate, elle a dit. Comment pourrait-on obtenir une hypothèque de 30 ans si les documents de la ville indiquent que toute la rue pourrait être condamnée à l'avenir et transformée en plage ? Comment obtiendra-t-elle une assurance ou des permis pour rénover sa maison?

"Le public a droit à la plage, mais je n'ai apparemment pas de droits sur ma maison, ", a-t-elle déclaré après une réunion particulièrement houleuse qui a opposé les propriétaires aux écologistes. "Je suis un démocrate de gauche, mais ces fanatiques de l'environnement sont d'un niveau supérieur."

La question a divisé cette ville très unie, whose residents open conversations by touting the number of years they've lived here and—in recent months—by how many feet they live above sea level. Outbursts at council meetings have become the norm, and depending on who's angriest that day, écologistes, the real estate industry, the city or the California Coastal Commission is Enemy No. 1.

The specter of managed retreat has galvanized retired engineers, policy wonks—even the president of the local Democrats club—to speak alongside real estate groups, worried that Pacifica will become "an economic wasteland" if the long-term vision is retreat. They accuse the city's study of undervaluing homes, entreprises, hiking trails and golf courses when calculating the public benefits of letting go. Preserving tourism, businesses and development opportunities, they said, should play into any future plan.

Others say Pacifica has already outlived its time. There's a reason why an empty parcel by the water has failed for years to attract developers, they said, and why the Taco Bell can still afford prime oceanfront views.

How much Pacifica ultimately decides to retreat, both sides agree, could be the litmus test for what's going to happen to the rest of California.

One recent morning, Drake stood on her second-story deck and talked over the roar of sand dozers clearing roads. The area floods whenever waves top the seawall or there's a break in the berm. The city brings in a pump during the winter to push stormwater back into the ocean.

Without that seawall or berm, her neighborhood and the nearby golf course would easily flood. Without these kinds of defenses, sewage lines, les stations d'épuration des eaux usées, schools and other public infrastructure would be at risk.

What officials need to do, Drake said, is build larger seawalls and commit to saving the town. She sees Pacifica on the cusp of becoming something special—a town that could finally have a nice library, peut-être, or a beautiful downtown with coffeehouses and places to shop.

The big white house next door sold not long ago for more than $1.5 million, elle a dit. Pacifica is still worth something, so why would officials let it go?

City officials have heeded the backlash and rewritten their plan to address the rising sea. Key seawalls will be extended, and the words "managed retreat" have been replaced with references to environmental triggers for "adaptation strategies" in the coming decades.

Many still distrust where this document is headed. John Keener, who championed the issue as mayor before losing his bid for reelection, wonders how much will change under the new leaders in power.

Walking along Esplanade Avenue one recent afternoon, Keener points to the orange tape and bits of foundation still poking out from where apartment buildings once stood. Only the odd-numbered homes on this block remain, the even-numbered side making way for sweeping ocean views.

Keener, a retired biochemist, winces at the words "managed retreat" and said he didn't want to devalue anyone's home or give up on the town. He just looked at the data and tried to think ahead.

The city has little money to build bigger seawalls, no money for sand replenishment, no money to compensate homeowners for the loss of their property. So he reasoned that Pacifica had a better shot of getting outside funding by showing it had thought through every option and come up with a plan.

Worrying about what this planning document would do to home values is a privilege with an expiration date. He fears that by 2050, "this stuff will all become moot."

"We'll be in survival mode, " he said. "The other aspects of climate change are going to simply just overwhelm us as a society."

He takes out his new business card, embossed with the words "Environmental Advocate." "What kind of world, " he wondered, "are we leaving for our kids and grandkids?"

Seawalls—Protection at what cost?

Your home is your castle, the biggest investment most families make. So the impulse, bien sûr, is to defend it.

The go-to tactic is the seawall. Made from piles of boulders, gunite-coated cliffs or concrete slabs as high as two stories, seawalls dissipate wave energy and fend off surging water. But these defenses aren't cheap. A single homeowner can spend as much as $200, 000. A mile-long wall can cost taxpayers tens of millions of dollars. Repairs sometimes cost as much as the wall itself.

Defending the entire state could cost homeowners and taxpayers more than $22 billion in the next 20 years if the sea rises even a moderate amount, according to a recent study by the Center for Climate Integrity.

And each seawall is a choice, conscious or not, to sacrifice the beach in front. The barriers disrupt the natural replenishment of sand, stripping away beaches until they narrow or vanish altogether. Some states have banned new seawalls:Oregon, Caroline du Nord, Maine. Others have imposed significant restrictions.

En Californie, environmentalists have called seawalls a coastal crisis. The Coastal Commission, in charge of regulating and shaping the state's 1, 200-mile shoreline, has historically OK'd them in emergencies—temporary solutions after a rough storm.

But temporary often becomes permanent. About 30% of Southern California's shoreline today is behind some form of seawall—locking in Navy bases, rail lines, harbors and multimillion-dollar homes at the expense of open space.

"Seawalls kill beaches, " said Jennifer Savage, California policy manager for the Surfrider Foundation. "I feel like a broken record saying this, but there is still such a disconnect with the public on such a key, simple message:Sea level rise doesn't just impact homeowners; it impacts every person who wants to go to the beach."

And the beach, state law declares, belongs to everyone. So the Coastal Commission in recent years has gotten tougher on seawalls. It urged city leaders to do everything within their power to consider alternative options, including managed retreat.

But that position has not won the commission friends among homeowners and local planners. City leaders often blame the state and the commission when taking unpopular steps. But the commission, when confronted by the public, says it's just offering guidance.

More than 30 cities and counties are now left paralyzed, tugged left and right to do something—but not sure what that is. There's no clear set of directions, no one-size-fits-all solution.

For the homeowner, insurance policies, hazard grants and federal disaster relief are all set up in a way that encourages rebuilding rather than relocating. There's no incentive for owners to consider options beyond hunkering down with bigger and better walls. The way the state pushes down insurance prices also masks the true cost of living in a hazardous area.

But the more hazardous it gets, the more the public could pay:As rising seas and storms exacerbate property damage, experts worry that the inability of insurers to charge prices that reflect actual risk could lead them to stop offering coverage in California.

If insurers stop covering risky properties, the state becomes the last resort.

That happened with earthquake insurance, when California stepped in to stabilize the market with insurance that companies could sell in lieu of their own. Officials are now confronting this in wildfire areas. Similar pressures are playing out in hurricane-prone states, according to a Stanford study led by a former coastal commissioner.

And so states, and ultimately taxpayers, are the ones subject to the biggest financial risks when a disaster hits.

Judy Taylor, a state director of the California Association of Realtors who has lived along the coast in the Half Moon Bay area for 45 years, said uncertainty over sea level rise planning has upended her world of clear rules and clean transactions.

Realtors are in a bind. Unlike other hazard zones in California, there are no mandatory disclosures for homes that might be subject to relocation or other sea level rise plans in the future. Clearly defined disclosures would help people better understand whether the home they're buying could actually be a long-term investment.

"Right now if we over-disclose, it's going to sabotage the seller's transaction, " Taylor said. "If we under-disclose, then the buyer is going to have serious heartburn."

What's debated by her industry is not so much climate change, elle a dit, but how much longer owners can extend the life and value of homes—and how they can do so while navigating the bureaucratic system of coastal permits.

"We have dealt with property being taken for bridges, for roads, for even shopping centers. But we have never before dealt with the fact that Mother Nature's going to do what she's going to do, and we can't do anything about it, " Taylor said. "So how do we treat this issue sanely and fairly? Do these policies actually further the goal, do they create a better environmental outcome—and is your ox getting gored and mine left free?"

San Francisco—Choosing casualties

On one side of San Francisco, a century-old seawall keeps the city's iconic towers and skyscrapers firmly on land.

On the other side, a rock wall protects a road, a parking lot and a sewage treatment system—squeezing away one of the city's few beaches.

Something needs to give. But even in a city as climate-aware as San Francisco, making sacrifices is not easy.

What is now the city's commercial core was once mostly a marsh—the shoreline a muddy half-mile farther inland. Over the decades, settlers filled in these wetlands and created more than 500 acres of new land atop old coves and abandoned ships.

Holding back all the water is the Embarcadero, doubling as a tourist attraction and bustling today with visitors and schoolkids, markets and museums. Humming beneath their feet is a network of critical infrastructure—sewer and water systems, utility lines, transport public, communication cables—that could cave to the ocean without this seawall.

There's no doubt defenses here must survive. This colossal feat of rock and concrete keeps San Francisco Bay from drowning the financial district and Market Street, safeguarding some $100 billion in business and buildings.

But the wall is crumbling and in desperate need of backup. High tides routinely spill over and flood sections of the boardwalk. With just 3 more feet of sea level rise, the iconic Ferry Building could flood every single day.

Updating this seawall will cost at least $2 billion, probably much more. Scientists from the U.S. Geological Survey recently found that the cost of building levees, seawalls and other measures to withstand 6 { feet of sea level rise and a 100-year storm could cost as much as $450 billion for San Francisco Bay.

Making people care has not been an overnight process. Lindy Lowe, the Port of San Francisco's resilience officer, reflected on all the neighborhood meetings, family nights and door-knocking to get taxpayers to understand the issue.

It was crucial, she learned, to actually work with the community from the beginning rather than doing all the research behind the scenes and then dropping a report full of government mumbo-jumbo declaring the city doomed.

"Never start a conversation with sea level rise is what we learned. Start the conversation with:'What do you care about? What do you want your community to look like?' " Lowe said. "We're asking people to do some really big things, and we need to make sure we're not asking them to do it all at once."

So San Francisco started by asking voters for $425 million to lay the foundation for a bigger seawall. Last fall, 82% of them said yes—a huge feat in a world where shelling out this much money usually comes only after a big disaster.

Defense proved to be a feasible sell, but retreat on the other side of town took much more convincing.

At South Ocean Beach, a popular spot for big surf and bonfires, more than 275 feet could disappear by 2100. The waves once devoured more than 40 feet of bluff in one season. Pendant des années, city officials fought—even sued the state—to keep a protective rock wall.

There was Great Highway to defend, they argued, and also critical facilities underground. La ville, in compliance with the Clean Water Act, had just spent close to $1 billion building infrastructure to prevent untreated sewage from overflowing into the ocean. Utility officials balked at the thought of retreat. But with each season, more beach disappeared.

It was a choice between two environmental imperatives:Preserve a popular beach or have clean water? SPUR, the San Francisco Bay Area Planning and Urban Research Association, finally stepped in to referee all the city, state and federal agencies as they picked their casualties.

They had few examples to look to for guidance. Only a handful of managed retreat efforts were underway in California at that time—and each was a lesson in the cost and time it takes to give something up.

More than 200 miles south on the coastal highway, by Hearst Castle and the Piedras Blancas Light Station, Caltrans spent $57 million moving a 2.8-mile stretch of Highway 1 more than 400 feet inland. Coastal bluffs by then were eroding an average of almost 5 feet a year. Planning and approvals took almost 15 years.

Moving the roadway and three homes was a win for the public, adding 75 acres to Hearst San Simeon State Park and creating new coastal trails. The open area is now a popular stop for motorists, who marvel at the many elephant seals returning each year to mate and care for their pups.

Officials in Ventura County spent nearly two decades getting all the pieces in place to turn an eroding parking lot and collapsing bike path into a cobble beach backed by vegetated dunes. This has fended off storm surges, and the beach is now one of the most popular in the county.

And across the nation, buyout programs so far have occurred mostly after disasters and predominantly in less wealthy communities. These, trop, have taken time. Two years after Hurricane Harvey, some residents in Texas are still waiting their turn. À New York, numerous neighborhoods begged for buyouts after Superstorm Sandy—but officials could afford only so many. And even with $120 million, which bought out 300 homes on Staten Island, that funding would probably amount to 10 or so homes in Malibu.

After years of deliberation, San Francisco finally agreed to take down the rock wall, remove two lanes of the coastal highway and turn the open space into a coastal trail.

Even this plan for retreat came with some compromises:A shorter, "low-profile wall" will protect the wastewater treatment facilities. Sand replenishment, on the order of 2 million cubic yards every few decades, will balance any beach loss from this wall.

Homes and personal fortunes weren't even at stake in this case, but choosing one public good versus another proved similarly fraught.

"Nobody was in charge of thinking about the big picture, " said Benjamin Grant, who led SPUR's Ocean Beach Master Plan. "But if you start early, it can be considerably less painful ... than waiting for a crisis."

Officials have since convened a sea level rise task force, created an action plan, established new regional strategies. Finding the long-term answers, many now say, requires thinking beyond parcel by parcel and instead coordinating across city boundaries and looking at the entire shoreline.

"The whole region is going to need to see these trade-offs on a grand scale. It may well be that you wipe out beaches in one section of coast and preserve them on other sections of coast ... but we're ill-equipped for that, " said Aaron Peskin, a San Francisco supervisor who serves on both the California Coastal Commission and San Francisco Bay Conservation and Development Commission. "It's either planned retreat or unplanned retreat. One way or another, we'll have to give something up. ... So if we're going to do it right, shouldn't we have a sensible set of plans?"

Big-picture planning has proved possible elsewhere. In the state of Washington, leaders are pledging no overall net loss of the coast's remaining wetlands. A similar approach in California could help decide what to save and what to abandon:Destroy a beach here to protect critical infrastructure; move back elsewhere and restore a beach.

David Revell, a coastal geomorphologist who has consulted for a number of cities, said this kind of policy forces leaders to consider what sacrifices could be made versus where along the coast must be defended.

"Pick where, " he said. "Just don't say everywhere."

Replenishing beaches—A race against nature

People often talk about the beach as a thing, a place, an area that doesn't move. En réalité, a beach is more of a process.

Imagine a river of sand moving parallel to the shore, from Malibu to Santa Monica to Manhattan Beach, until the ocean pulls it offshore. This sand is always on the move, flowing down from mountain streams and waterways and stopping only temporarily on any specific beach.

Any human disruption to this river of sand could reveal itself elsewhere. Pacifica may be eroding so quickly in part because of all the sand dredging farther up the coast in San Francisco Bay. Many Malibu beaches have lost significant amounts of sand after the building of Pacific Coast Highway. In Santa Monica, fresh sediment rarely reaches the coast now that humans have dammed up the creeks and turned the L.A. River into a concrete channel.

Los Angeles responded to these alterations of nature with more alterations. Adding sand to the beach began as early as the 1930s in Santa Monica Bay. Breakwaters, jetties and other retention structures have also been constructed to help hold in all the sand. Par conséquent, these iconic beaches are 150 to 500 feet wider than normal.

Beach towns like Del Mar, a tiny affluent enclave north of San Diego, have all but declared this to be their survival tactic.

Tucked among sandstone bluffs, two lagoons and the rarest pine trees in America, the picturesque town bustles every summer when the fairgrounds and horse track come to life. Prime real estate clusters around where the San Dieguito River meets the Pacific.

Dry sand here was once abundant, the beach twice as wide today. Private seawalls now protect multimillion-dollar homes that early settlers had built right on the sand. On the southern end of town, train tracks run precariously close to the edge of rapidly crumbling cliffs.

But as word got out that those in charge were considering managed retreat, the town exploded. Relocating could mean allowing the ocean to claim as many as 600 homes.

If you start retreating, residents demanded, where do you stop?

"If you let the first row of homes go, the whole area behind it floods, " said Jon Corn, a resident and attorney representing dozens of homeowners in the Del Mar Beach Preservation Coalition. "And then what about the next road? And the road after that? ... At some point, everyone is going to say:'No, we're not just going to retreat away from the ocean.'"

City leaders finally agreed and said they would keep an open mind about relocating the rail line, the fire station and other city-owned infrastructure—but took out any mention of private property. The land here is too valuable, they reasoned, and the threat of lawsuits too high. Adding sand will be the solution for now.

Terry Gaasterland, a data scientist who led the sea level task force and ended up running for office over the issue, said she's confident more studies and more time will uncover ways to coexist with the ocean and save the town.

Del Mar can afford to both protect homes and save the beach, said Gaasterland, who's now on the City Council. "We're not going to be packing our bags."

But if past sand projects are any indicator, Del Mar and its neighbors might be in for a surprise. For every jetty and breakwater that has helped keep Santa Monica and Venice wide and sandy, Dockweiler and beaches farther down the coast in turn needed their own supply of sand, which then disappeared and flowed onto beaches farther south.

Sand, although it might seem limitless, is not free. It's the most exploited and consumed natural resource in the world after fresh water. Federal agencies, États, cities and private companies across the nation are all trying to stake their claim.

And because sand is always on the move, adding more of it is anything but permanent. Erosion runs its course all the same.

This makes "beach nourishment" difficult to sustain. Adding 240, 000 cubic yards of sand—the amount, par exemple, to make a half-mile-long beach about 100 feet wide—requires 24, 000 dump trucks full of sand. Even working seven days a week, it would take more than 16 months to bring in that much sand. Depending on how fast the sand washes away, a project of this scale would need to be repeated every few years, according to reports by Gary Griggs, who has studied coastal systems across California and taught at UC Santa Cruz's Institute of Marine Sciences for more than 50 years.

En 2001, officials in San Diego County pumped about 2 million cubic yards of sand from offshore onto 12 beaches—the first large-scale attempt by California officials to add sand to disappearing beaches. It cost city, state and federal taxpayers $17.5 million.

The effort was short-lived. Most of the beaches had narrowed significantly by the following year. The extra sand, Griggs found, "was removed within a day when the first large waves of the winter arrived." A second attempt by the county—with twice as much money—yielded similar results.

These costs have also paralyzed communities along Malibu's disappearing shoreline. Broad Beach, once so wide that dunes had room to grow along the sand, now hardly lives up to its name. Building mansions on the sand also took up about 200 feet of the beach and dunes, leaving only a narrow buffer against the rising sea.

Sand was disappearing so rapidly that a rock wall was built to protect the septic system and the homes. Ces jours, there is little beach left during high tide. The public stairs drop straight down into water.

Owners years ago agreed to pay $19 million to add sand to the beach. The project has been delayed by disputes over the source of sand and legal challenges over the costs, which keep going up. The current price tag to save this stretch of beach:$65 million.

Imperial Beach—Grappling with retreat

At the very southernmost edge of California, a world away from Malibu, the border town of Imperial Beach seems to be living on borrowed time.

One-fifth of the residents here are lower-income. High tide soaks the road every winter. Sewage spilling from Tijuana regularly shuts down the beach. Those living below sea level recall floodwaters so high in the 1980s that they had to use canoes.

Aujourd'hui, they board up windows and brace for storms. Surrounded by the ocean, a bay and a river, Imperial Beach is looking at losing one-third of the town if nothing is done, one official said. Hazard maps show blocks and blocks of homes that could be flooded by 2100. A beach nourishment effort seven years ago went awry because the sand grains were too coarse. Sand berms and rock walls will last only so long. Moving back seems inevitable, even if the community isn't ready to say so.

The reptilian frenzy over managed retreat has overtaken Imperial Beach, as it has in other cities. Fear overwhelms reason. Conspiracy theories and misinformation abound. Some think the mayor, an environmentalist known for his history of preserving open space, just wants to turn the town into one giant lagoon.

With the city barely able to scrap together a $20-million budget every year, others say letting go of prime real estate means abandoning the whole town.

"If you get rid of the waterfront, the municipal tax base, how do you support the city?" said City Councilman Ed Spriggs, who lives along the water and questioned managed retreat as a strategy. He points to the city's first upscale hotel, which was built in 2013 with coastal defenses, as a sign that Imperial Beach has time to survive and thrive well into the future.

As chair of the coastal cities group for the League of California Cities, Spriggs sees what's been happening across the state and calls managed retreat an ideology being pushed by extreme environmentalists with no rules or standards.

"Nobody has explained how urbanized managed retreat works, what it would look like and how it would be paid for, " he said. "We need time to build a consensus. We don't even have money for ... more detailed studies on what the actual costs will be."

But time is ticking. Plus tôt cette année, a group of scientists from the Scripps Institution of Oceanography gathered on an apartment balcony and watched in awe as the ocean devoured more than 3 feet of sand in one morning.

"When that surge came over the seawall, it was just a blanket of water. There was so much force, " said Mark Merrifield, director of Scripps' Center for Climate Change Impacts and Adaptation. "It was just crazy."

His team has been studying ways to forecast floods and were watching that morning because they knew the waves would be particularly powerful. Their data had projected that this would come just ahead of a king tide—when the sun, moon and Earth are aligned closest together, creating a higher-than-high tide. They had alerted Imperial Beach, which filled more than 500 sandbags just in time and warned residents to board up their homes.

These king tides are becoming a new normal, said Merrifield, whose team hopes to fill in data gaps that could help more communities better understand their risks. Imperial Beach doesn't even track the number of times the ocean tops the seawall—crews just clean the road before most residents wake up.

Tracking the frequency of flood events, and how much it's increasing, will make these truths harder to ignore. There's no debate, il a dit. "Sea level rise is the heart of climate change. That's where all the heat is going:into the ocean."

That rising ocean, depuis des décennies, had spared California. Much of the state's coastal development took place in the years after World War II, during the less stormy period of a climate cycle known as the Pacific Decadal Oscillation. Favorable winds pulled warmer water offshore and the West Coast had cool, denser water that took up less volume—suppressing the rate of sea rise below the global average.

But scientists in the last decade have seen a dramatic shift:The waters off the West Coast are now much warmer; the sea is now rising faster here than elsewhere in the world.

The morning after the worst of the surge, Imperial Beach Mayor Serge Dedina parked his Prius and hopped around puddles still pooling down Seacoast Drive. Vagues, still breaking over the rock barriers, spewed sand across the road. A maintenance worker sprinted toward the nearest driveway, startled by yet another rush of water.

An avid surfer, Dedina has watched this ocean obsessively his whole life. But taming the water has been all-consuming. Cleaning up just from this king tide cost Imperial Beach $16, 000 and left 350 hours of calls unanswered and other work unattended to around town.

Imperial Beach can't afford more seawalls, more sand, more meetings filled with 150 people yelling at him about managed retreat, il a dit. The town doesn't even have a Parks Department. It just got its first real grocery store.

The city and its consultants have come up with some big ideas—but lack the political support and capital to get started. Buy out these first few row of homes along the coast, par exemple, and rent them at market value. Three decades of rent should be enough to recoup the costs. The city or a land trust at that time could then decide what to do with the properties.

Pour l'instant, Dedina is focused on relocating some public infrastructure and building more homes and businesses further inland. He's also suing a number of oil companies in hopes of funding, arguing that they should be held responsible for the costs of coastal flooding because their emissions contribute to sea level rise.

"Finalement, the city can't protect private property owners. We need to be upfront about that, " he said. "The insurance industry or the state needs to figure that one out."

The state has taken some action but is largely still confronting this 21st-century problem with decades-old laws and thinking. The California Coastal Act—the defining road map to managing the state's shoreline—did not factor in sea level rise when it was written in 1976.

Lawmakers are aware of the problem, and they have told cities they must start addressing climate adaptation in their planning. But Sacramento has otherwise shied away from issuing mandatory directions. The California Coastal Commission, through modest grants and some general guidance, has been encouraging local officials to consider "everything in the toolkit, including managed retreat, " when updating city policies.

Phil King, an economist and professor at San Francisco State University who has consulted for a number of beach cities, said that what Californians need is a clear statewide plan. Managed retreat sounds scary, but it just means retreating with everyone knowing what the rules are, il a dit. Will there be a public subsidy, how is it going to be applied, who's going to get it, and does everyone think it's fair?

Bankruptcy law could be a model, il a dit, because it makes a messy process as orderly as possible. Managed retreat is similar:Dealing with a loss and making sure that everyone absorbs the loss in the most reasonable, equitable way.

"À l'heure actuelle, managed retreat is just a slogan. It needs to become a reality where we actually talk about:How are we going to actually manage the retreat?" said King, whose studies showed that retreat does end up penciling out for many communities as the most cost-effective solution in the long run. "If we start to think about managed retreat today, we can avoid the problems that people had with the fires in Paradise, where all of a sudden everything just disappears."

Imperial Beach's buyback-and-rent proposal is one idea, il a dit. And if a seawall has to exist in the short term to protect private property or infrastructure, perhaps a greater authority like the State Lands Commission could charge rent for it. These funds could then be used toward other efforts to manage and preserve the coastline.

Much of California's climate change efforts have centered on reducing carbon emissions and the rate of global warming, rather than dealing with how to live with these increasing hazards, said Heather Cooley, directeur de recherche de l'Institut du Pacifique, an Oakland think tank that has studied the economic impact of sea level rise.

"We need to do both, " she said. "We're already locked into a certain amount of climate change, and we need to adapt to the effects that we know we're going to be experiencing."

A few bills under consideration now in Sacramento acknowledge these problems—appointing a chief climate resilience officer, calling for a plan to reuse dredged sand for coastal restoration projects, creating an inventory of the state's wetlands and a special fund for "coastal adaptation, access and resilience"—but none tackles managed retreat head-on.

"Living shorelines, " which substitute seawalls with vegetation that could serve both as protection and public open space, has been gaining popularity as a less politically fraught approach. Some lawmakers see this as a way to buy more time as the backlash over relocation continues.

The fear of political suicide should not paralyze those in power from studying the how, where and why of managed retreat, said Katharine Mach, a senior research scientist at Stanford who has helped lead national and global climate change assessments.

In the same way state leaders paved the way on other environmental issues, what California does now on managed retreat could help set some standards for others across the country, elle a dit.

Jack Ainsworth, executive director of the Coastal Commission, points to the work his agency has done within its legal power.

Commissioners are tough on any new construction that gets in the way of the rising sea. They passed a resolution last year pledging that seawalls would be permitted only if absolutely necessary. They're butting heads with homeowners and real estate groups, drafting a new guidance document for cities to use to balance preserving coastal resources and protecting homes.

Au-delà de ça, il a dit, the commission is stuck. Only lawmakers can establish new disclosure laws. Only state, city and federal leaders can determine how much money they are willing to spend to come up with a clear plan for the future, et ultimement, how to pay for the retreat where necessary.

Across the state, and the nation, many people know the sea is coming and exactly what's at risk—but no one seems ready to drop that first domino and rattle the status quo. "This conspiracy of silence, " as one economist from the Union of Concerned Scientists publicly called it, can go on for only so long. Society as a whole saves $6 in avoided costs for every $1 spent to acquire or demolish flood-prone buildings before disaster hits, Ainsworth said.

When staff is short or pressure comes from those wealthy enough to fight back in perpetuity, the Coastal Commission has in the past pushed tough issues down the road. But Ainsworth said California cannot afford that with sea level rise.

"People have to understand, " il a dit, "that this is a crisis."

Gleason Beach—A lost coast

A few winding turns past Bodega Bay, about an hour north of San Francisco, relentless waves pound against a stretch of coastline whose fate has been paralyzed by political inaction.

Once referred to as Malibu North, Gleason Beach now feels more like the edge of the world—a window into the future if California does not change course. Nine homes perch on crumbling cliffs that drop 30 some feet onto a beach that appears only during low tide. A pile of seawalls, smashed into pieces, clutters the shore.

Rebar and bits of concrete poke out here and there—a graveyard of more than 10 other homes that once also faced the sea. Highway 1, hanging inches from the edge, had to shut one traffic lane this year.

"Behold your highway tax dollars falling into the ocean, " locals say. But efforts to move 0.6 miles of this critical road about 400 feet inland have taken more than a decade. Residents, écologistes, and state, county and transportation officials are still arguing over the details.

Mary Cook remembers moving into a seaside cottage from the 1930s. Photos back then showed the house with a 20-foot yard. Stairs led down to the beach.

Her husband, an architect, made a few additions to their home as the bluff continued to erode about a foot a year. They put up a seawall. But then in the winter of 1997, one big storm took out the entire cliffside. Officials came in and declared an emergency.

When Cook opened her sliding door, "there was nothing, " she said. "You looked straight down into the ocean."

Life for her neighbors eventually carried on. The storm ebbed from memory. The sun reemerged. The Cooks, cependant, were tired of buying time.

They jacked their home up from its foundation, called in a truck and moved to higher ground.

©2019 Los Angeles Times
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