Is This the End of Summer as We’ve Known It?

LOS ANGELES — In the state that perfected if not invented the American summer, the smell of 17 million gallons of spilled sewage lingered last week on a Southern California beach. There were bare rocks where snow once capped the Sierra Nevada and bathtub rings where water once glistened in Shasta Lake.

Wildfires roared across the West, threatening the electrical grid, the smoke so thick it could be seen from space, pluming into the jet stream, delaying planes in Denver, turning the sun red in Manhattan, creating its own weather. Health authorities warned that recent Death Valley-style heat waves had contaminated shellfish from Washington State. Monsoons swept cars from the road in Arizona. Pennsylvania songbirds were dying.

Welcome to the end of summer as we have known it.

The season Americans thought we understood — of playtime and ease, of a sun we could trust, air we could breathe and a natural world that was, at worst, indifferent — has become something else, something ominous and immense. This is the summer we saw climate change merge from the abstract to the now, the summer we realized that every summer from now on will be more like this than any quaint memory of past summers.

Wildfires, drought, sewage spills, a resurgent virus — separately, each is a familiar peril. But this year, the worst-case scenarios have arrived en masse and just as expectations were high that this summer would be especially joyful.

All that has changed in a welter of heat-buckled roads, freak monsoons and collapsed buildings. Our watchword has been “extreme” — extreme threats to public health, extreme violence, extreme division, extreme weather.

In Florida, algal blooms known as red tide have wiped out hundreds of tons of marine life. In the spring, a leak in the former Piney Point phosphate plant discharged more than 200 million gallons of wastewater into Tampa Bay.

Scientists wondered for months how that might affect red tide this year. Now, they have their answer. “The smell was just gross,” said Mia Huffman, 18, a tourist from Maryland who had come down to Florida’s Pass-a-Grille Beach in Pinellas County recently, just in time to witness a young boy reach into the water and pluck a foot-long dead fish.

America has known dreadful summers before. The summer of the Manson family murders in Los Angeles in 1969. New York’s Summer of Sam in 1977. The summer of 2019, when there were 26 mass shootings in 18 states, including one of the worst hate-driven massacres in modern American history at a Walmart in El Paso. What is different this time is the sheer volume of catastrophe, natural and man-made — and a sense that there is no turning back from it.

“Here in Los Angeles, we have had periods of extreme drought, and periods of extraordinary flooding, and political turmoil, and ecological degradation and a pandemic in 1918, and of course heat waves and wildfires,” said D.J. Waldie, a cultural historian and author in Southern California. “But they didn’t all come on the same summer day.”

Scientists say the disheartening pileup is the outcome of population- and climate-related pressures that they have been warning about for decades.

“Climate science couldn’t predict it would be in 2021, as opposed to 2017 or 2023,” said Rick Thoman, a climate specialist at the University of Alaska. “But it’s not unexpected, and we have a pretty good idea what the long run looks like: It will be a painful transition, and in a couple of generations, the world will be different — different than the world that was, and different than the world that is now.”

But unless greenhouse gas emissions are reduced, scientists say, the massive floods, severe droughts and catastrophic ocean warming the world is experiencing now will only worsen, generating bigger fires, more violent storms, more severe flooding and more extinction. The World Meteorological Organization reported last month that average temperatures on the planet already were consistently at least 1 degree Celsius warmer than in the late 1800s.

“You see gradual change for a while and then you reach this threshold of pressures that cause all hell to break loose — that’s what we’re seeing this summer,” said Anthony Barnosky, a Stanford University biologist who manages the Jasper Ridge Biological Preserve in the Santa Cruz Mountains, where he studies the impact of humans on the environment and other species.

The larger wake-up call is the dominance of humans, a fact so significant some scientists have argued it constitutes a new “Anthropocene” geological epoch.

“The Anthropocene has arrived,” Dr. Barnosky said. “Humans have become as great an influence on the planet as the asteroid that wiped out the dinosaurs.”

What that wake-up call looks and feels like this summer, day by day, has not been reassuring as Americans turn up their smoke-cleansing air purifiers — the new must-have for Western households — and dodge awkward encounters with the vaccine resisters next door. It has shown up in ways as small as the ticks whose numbers have exploded in the Midwest and as big as the cost of repairing roads atop Alaska’s melting permafrost.

In the Seattle area, it is on the payroll at Day & Nite Plumbing & Heating, where the staff worked 16-hour shifts for nearly a week during the recent heat wave. “I see that this will become the new norm, these extremes and things like this,” said Day & Nite’s co-owner, Bruce Davis Sr., who called for “all hands on deck” after requests for air-conditioning tripled to as many as 150 a day.

A recent study showed that there were probably many record-shattering days to come. Scientists project that if warming were to continue at a relatively rapid pace, record-breaking heat waves would be up to 21 times more likely toward the end of the 21st century compared with the past 30 years.

For many American children, this new summer may become all they ever know. The type of summer where a high school football camp moves inside a gym after a grim streak of 115-degree June days in Arizona; where school buses in Kennewick, Wash., become too hot to ride in and playgrounds become too hot to play on.

On a sunny, scorching July afternoon in Glendale in Southern California, a boy was perched on the climbing structure at Holy Family Grade School trying to start a summer school tag game.

Over and over, he called something no one could make out, his words muffled by a thick black face mask.

Finally, the boy yanked down the cloth and hollered the playtime question shouted by schoolyard children down through the ages, never mind the heat and the threat of airborne diseases.

He screamed, his voice defiant, his unbound face sweaty and flushed: “Who’s it?”

Hallie Golden and Elizabeth Djinis contributed reporting.