In July 2018, the air temperature in Woodland Hills, a Los Angeles neighborhood some 20 miles north of the Pacific Ocean, peaked at 117 degrees Fahrenheit. For 63-year old U.S. Post Office carrier Peggy Frank, that Friday marked her first day back at work after recovering from a broken ankle. At 3:35 p.m., Frank was pronounced dead after paramedics found her unresponsive in her non-air-conditioned truck. In September, the Los Angeles County coroner’s office confirmed what seemed a forgone conclusion: Frank died of hyperthermia — she overheated.

A few months later, in November, the Woolsey Fire swept through Malibu and parts of the San Fernando Valley. The blaze killed three and forced the evacuation of almost 300,000 people, burning 96,000 acres and destroying 1,643 structures. Then, after heavy rain in areas scarred by the fire, came the mudslides in December and January that killed one person and closed portions of the Pacific Coast Highway.

For most of the population, climate change is too big a thing to grapple with. As the theorist Timothy Morton argued, it’s a “hyperobject” — it is too big, too sprawling in time and space, and too complex to see fully from any single vantage point. It’s numbing. But by narrowing our focus, we can catch more than a glimpse. It may be easier to understand climate change at the regional level, says Katherine Davis Reich, associate director of UCLA’s Center for Climate Science. “We can all appreciate what climate change impacts would be in our backyard and act on that, much more than at the global level.”

Los Angeles, the second-largest city in the United States, is perched precariously on the edge of the Pacific. Not long ago, it was the nation’s frontier; today, its cultural industries produce the globe’s films, music, and television, always hunting for the next new thing. Here, the line between the present and the future has always been thin. As it swelters, burns, erodes, and collapses, that barrier may have been swept away altogether. For L.A., 2018 was not a sign of things to come. It’s a sign of things that have arrived.

That Los Angeles should exist at all is itself a tale of the extraordinary becoming commonplace. An underpopulated backwater until the discovery of oil in 1892, today’s L.A. is a thick smear of civilization over what may not actually be a desert, but what certainly has the mythic feel of one. Precariousness is the resting state of L.A.’s collective unconsciousness.

The city has been grappling with ecological collapse since its beginnings — and not just in films like Chinatown or San Andreas. In 1927, the Los Angeles Times warned of an environmental reckoning: “I was pessimistic enough to imagine that self-confident Los Angeles had forgotten Babylon, Palmyra, Palestine, China and Timgad. What I now saw was our own beloved land. And I saw sand dunes, sage brush, aridity, stately ruins, idle derricks, desolation.”

“By the end of century, a distinctly new regional climate state emerges.” This climate includes a new, fifth season: a super summer.

Even the most dire predictions don’t suggest that Los Angeles will go the way of Timgad — a Roman colony in modern-day Algeria that is now covered by sand. People will still flock here, and even if the city were to collapse, it would happen over a much longer time scale. Still, by 2069, Los Angeles could well be on the way to a new season of misery.

“With the exception of the highest elevations and a narrow swath very near the coast, where the increases are confined to a few days, land locations see 60–90 additional extremely hot days per year by the end of century,” one study concluded. Downtown Los Angeles could experience up to 54 days measuring 95 degrees or higher by 2100, a ninefold jump. By then, temperatures in Riverside could reach over 95 degrees for half the year.

“By the end of century,” the authors of the study found, “a distinctly new regional climate state emerges.” This climate includes a new, fifth season: a super summer, driving people indoors for weeks at a time, stressing the power grid with heavy demand for air conditioning, and wreaking havoc on agriculture and, by extension, the food supply.

Climate change plays favorites, and the heat increase would not be evenly felt. In fact, its unequal distribution could create an “environmental justice story,” explains Davis Reich. “Areas like the San Fernando, the San Gabriel Valley, or the Inland Empire, where the extreme heat burden is already greater, are where the season of extreme heat will occur — parts of the region that are arguably less well-equipped to deal with compared to places like Santa Monica.” There’s a dark irony there, since wealthier people produce more carbon emissions. “The people who have contributed to the problem the least are going to suffer from it earlier and more,” Davis Reich says.

Meanwhile, beaches in Los Angeles will be facing their own threats. Rising sea levels will attack the coast in at least two ways: inundating beaches and eroding cliffs. “Our beaches are compromised. Not just from overall sea level rise, but also coastal storm events,” says Lauren O’Connor Faber, the city’s chief sustainability officer.

In 2017, scientists modeled the effects of sea level rise on 500 kilometers of shoreline in Southern California. A sea level rise of 0.93 to two meters, they predicted, would result in the loss of 31 to 67 percent of beaches in Southern California, including some of its most well-known. A separate USC study concluded, “In Malibu, both low and high sea level rise scenarios suggest that long segments of beach will essentially disappear by 2030.”

“Those beaches are the basis for a lot of California’s identity,” said the first study’s lead author, Sean Vitousek, an assistant professor of civil and materials engineering at the University of Illinois at Chicago.

Vitousek was part of another research project predicting that because of rising sea levels, sea cliffs in Southern California would erode, on average, up to 120 feet over the next 80 years. By comparison, the rate of cliff erosion in California over the past 80 years maxed out at 1.5 feet. At the end of the century, the model predicted an increase in cliff erosion of “27–185% above historically observed retreat rates.”

Those changes put more than just surfers and beachcombers in peril. In 2060, sea level rise will likely put between 414 and 3,979 homes along the coast in the L.A. region at risk of flooding — up to $3 billion in value. Beach nourishment — artificially adding sand to bulk out the shoreline — is one option but may not be enough. The coast could be armored with sea walls, cliffs shored up, and sea gates constructed. Vitousek says that a shoreline retreat strategy might be needed — but it won’t be easy. “Because there is so much money involved in all of this, people will fight tooth and nail to keep themselves on the coast for as long as possible,” he says.

And as the coastline advances, the forests around Los Angeles have already begun to burn.

In December 2017, a series of 27 wildfires ignited in Southern California, including the Thomas Fire, which burned more than 281,000 acres across Ventura and Santa Barbara counties, resulting in two deaths and the evacuation of more than 200,000 people. Less than a year later, the Woolsey Fire burned 96,949 acres, spreading south from the mountains into Malibu, where it destroyed hundreds of homes and killed three people.

If you think think of 1994’s Northridge earthquake as L.A.’s signature disaster, the coming decades may make you reconsider. Because while climate change may not have much effect on earthquakes, it will lead to more — and more destructive — wildfires. The area burned by Santa Ana fires is predicted to increase by 64 percent by the middle of the century, compared to 1981 to 2000, while non–Santa Ana fires, which occur from June to September and are concentrated inland, will increase by 77 percent. The number of structures destroyed will rise as well — 20 percent for Santa Ana fires and 74 percent for non–Santa Ana fires. Santa Ana fires currently threaten 3,400 structures in an average year, while non–Santa Ana fires put 440 structures at risk per year.

Eventually, all that risk adds up.

“One thing that often gets lost is that wildfires are perfectly natural,” Davis Reich says. “These landscapes were made to burn and need to burn periodically to be healthy. When we build into our wildlands, there is a risk that our buildings will burn. We have to confront that more seriously than we have in the past.”

After fires destroyed a neighborhood in the Bay Area in 2017, local politicians debated the wisdom of rebuilding homes in high-risk areas. There was little appetite for such a move there (or for similar efforts in parts of Southern California), but eventually it may become too expensive to continue rebuilding in high-risk spaces. The Los Angeles Times mapped the 1.1 million buildings in California located in zones at highest risk for fires, showing clusters in the Santa Monica Mountains, the Palos Verde Peninsula, Mission Viejo, and Yorba Linda. Nearly all of Topanga, Paradise, and Malibu were also at risk. Few political leaders want to discuss managed retreat yet — but in 50 years, they may have to.

Climate change is no longer on the horizon. It has arrived.

The masterstroke that allowed Los Angeles to grow may be the one that causes it to retract: Los Angeles depends on imported water, whether from the Owens Valley or farther abroad. As the globe warms, those supplies will dwindle and become harder to manage. Sixty to 70 percent of the water used in Southern California comes from the San Joaquin River and Tulare Lake basins, the Sacramento River basin, Mono Lake, and the Colorado River basin. (The bulk of the remainder is pumped local groundwater.) Of that, 75 percent is drawn from spring snowmelt from the Rockies, the Sierra Nevada, and other mountain ranges.

The Fourth National Climate Assessment, released in November 2018, projected “substantial reductions in snowpack, less snow and more rain, shorter snowfall seasons, earlier runoff, and warmer late-season stream temperatures.” Snowpack reduction in Southern California mountains could reach as high as 50 percent by the end of the century. At the same time, water flow in the Colorado River could be down 35 to 55 percent.

Water demand in 2050 is projected at 1.4 million to 1.7 million acre-feet per year, while supply is projected at 1.4 million acre-feet per year. At best, it’s break even. At worst — well, ask Cape Town.

And those estimates may underrepresent the risk to L.A.’s water supply. A 2015 study concluded that “the mean state of drought in the late 21st century over the Central Plains and Southwest will likely exceed even the most severe megadrought periods of the Medieval era,” causing “an unprecedented fundamental climate shift with respect to the last millennium.”

Another study conducted in 2016 found “a pronounced increase of droughts and aridity in the Southwest during the latter half of the 21st century.” A megadrought — one that would last multiple decades — “could become commonplace.” Droughts of that magnitude were associated with collapse of the Angkor, Anasazi, and Maya civilizations.

There are two futures in front of us,” says O’Connor Faber, CSO of Los Angeles. “One in which we do not act, do not take leadership. We let the disasters happen. That’s an untenable future. The good news is that’s not at all the future that L.A. accepts.”

It’s not a future that the state of California hopes will come to pass. In 2006, the state enacted a cap-and-trade system to reduce its carbon emissions. A new state law mandates that by 2045, California will rely solely on clean electricity. In recent sessions, state legislators have begun to reshape the laws that govern the state’s housing market, hoping to encourage denser buildings oriented around mass transit, rather than sprawl that forces drivers onto jammed freeways.

For its part, the city of Los Angeles has embarked on an ambitious effort to do what it can. As Mayor Eric Garcetti told Rolling Stone in September, “We’re not waiting for Washington. The cavalry isn’t coming.

So the city is building up local water supplies and curbing demand, increasing the tree canopy and building out cooler infrastructure to reduce its heat island, spurring the installation of solar power, and armoring its beaches and the ports of Los Angeles and Long Beach. Progress has already been made: Emissions at the port have dropped by double digits, tens of thousands of electric vehicle chargers have been installed, and improvements in public transit are coming.

As she works through the list, Faber O’Connor says she recognizes the magnitude of the task but has reason to hope. “I’m feeling very positive,” she says. For her city, climate change is no longer on the horizon. It has arrived. And like a car speeding down a clear freeway, the city is racing to catch up.