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Extreme Heat Will Change the World As We Know It

An excerpt from Jeff Goodell’s new book The Heat Will Kill You First tells the story of Jonathan Gerrish and Ellen Chung, who died on a scalding hike with their one-year-old daughter.
Luis Sinco /Los Angeles Times/Getty Images

W hen the babysitter arrived to take care of Miju at around 11 a.m. on Monday, August 16, 2021, she was surprised to find the house empty. Miju was the one‑year‑old daughter of Jonathan Gerrish and Ellen Chung, who had recently fled the Bay Area to start a new life in California’s Sierra Nevada foothills, not far from the old Gold Rush town of Mariposa. Their modern three‑bedroom house sat on ten acres of lightly forested land. It had wood floors and a big stone chimney and tall rectangular windows that looked over a rugged treeless canyon called Devil’s Gulch. From the second‑floor bedroom, you could just see the top of El Capitan, the iconic granite formation in Yosemite Valley, about thirty‑five miles to the east. The house was their refuge from the hustle of Silicon Valley, where Gerrish worked as a software engineer at Snapchat, the instant messaging app company.

The babysitter, who had a key, let herself in and called out their names. No response. It had been a hot weekend, but the inside of the house was cool, thanks to the air conditioner, which was going strong. Oddly, Chung and Gerrish had left behind their wallets. Even more confusing, the diaper bag that the couple always took with them was there.

The babysitter had last seen them the previous Friday when she had finished straightening up the house. That evening, Chung had happily texted her a video of Miju starting to walk. She had made no mention of plans to be away that Monday. Gerrish and Chung, who doted on Miju and seemed deliriously happy with their new life in the Sierra foothills, were not the kind of people who would disappear for a last‑minute road trip to Las Vegas.

Worried, the babysitter called the construction manager who was working with Gerrish on another home he owned, and whom she knew was in frequent contact with him. The construction manager was not initially concerned because Chung and Gerrish were a “very active family,” an investigator later wrote in the police report. Nevertheless, the babysitter and the construction manager started making calls and sending texts to friends, asking if anyone had seen the couple. Steve Jeffe, a friend who lived in Mariposa, posted on Facebook: “Hi, please has anyone been in contact with Jonny Gerrish or Ellen Chung in the last two days … Please.” By 5 p.m. that day, several friends began driving around looking for the family. At 11 p.m., they called the Mariposa County sheriff.

A few hours later, a deputy sheriff found Gerrish’s truck at the Hites Cove trailhead a few miles from their home. By 4 a.m., a search and rescue team was on the scene. They headed down the trail in an ATV, flashlights cutting through the darkness. They radioed back that they had found tracks on the trail. But when they followed the tracks down to the Merced River, the tracks disappeared. By that time, the sun was rising. A helicopter was called in. More search and res‑ cue teams arrived. One team headed down a steep trail with numerous switchbacks toward the river. They were a mile and a half down the trail when, at about 9:30 a.m., they discovered the bodies of Gerrish, Miju, and their dog, Oski. Gerrish was in a seated position, with Miju and Oski beside him. At first, the search and rescue team saw no sign of Chung.

About a half hour later, a deputy walking back up the trail from where Gerrish was found noticed “some disturbed dirt on the uphill side of the trail that appeared that something or someone had tried to go up the hill.” He spotted a shoe, then Chung’s body. Investigators would later conclude that the family had been hiking up the trail when they died. The location of Chung’s body indicated that she had abandoned the trail and was climbing straight up the mountainside — a sign, investigators believed, of the urgency of their situation and her desperate attempt to reach their truck. 

But even if Chung had made it to the truck, she might not have been able to get in. During a search of the area, investigators discovered a Ford key fob on the trail about a hundred feet below Gerrish’s body. Had it accidentally fallen out of his pocket? Or did he have it in his hand and drop it and not realize it — perhaps a sign that he had been panicked or disoriented?

Rescuers found no signs of foul play. No marks on the bodies, no obvious signs of struggle. Because of the remote location and the difficulty of the terrain, the bodies could not be removed immediately. Instead, two deputies spent the night at the scene, guarding the bodies from bears and coyotes. The next morning, a California Highway Patrol helicopter airlifted the family off the trail.

Gerrish and Chung had moved to Mariposa about a year and a half earlier, just before Miju, their first child, was born. They had been living in San Francisco, where Chung taught yoga while finishing her degree in counseling psychology, and Gerrish wrangled computer code at Snapchat. But then Miju came along and the Covid‑19 pandemic erupted and they needed a change. They decided they wanted to get out of the city and raise Miju closer to nature. Mariposa, which is just an hour outside the entrance to Yosemite National Park, was an ideal mix of wilderness and charm. “They fell in love with the Mariposa area,” one friend of the family said.

Little, Brown and Company

Gerrish and Chung both doted on Miju. You can see it in every photo of them together, the big beaming happy‑father smile on Gerrish’s face, the joy and new‑mother exhaustion on Chung’s. And Miju, waking up to the world, her eyes wide. She was just beginning to walk, to track birds flying across the sky, to take in all the wonders around her. Gerrish and Chung were protective of their young daughter, and careful about her surroundings. At one point, they asked a local con‑ tractor to make their daughter’s bedroom cooler because it was “too stuffy.”

The day before their hike, Gerrish mapped out the route using the AllTrails app on his Google Pixel 4. The app helps users find local trails, giving maps and elevations, as well as a place for other hikers to leave comments. Gerrish had logged sixteen hikes in 2021, most of them three or four miles long, all of them in the mountains and canyons near his house.

The hike he planned for his family was not a remote wilderness adventure. It started at a trailhead a few minutes’ drive from their house and ended at the top of Devil’s Gulch, which was practically in their front yard. The trail went along a ridge, then down fairly steeply to the south fork of the Mer‑ ced River, which flowed out of Yosemite and through the canyons toward Mariposa. The trail wandered along the flat ground on the banks of the river for about three miles. From there, Gerrish plotted a right turn, which would take them on a steep 2,300‑foot climb through Devil’s Gulch and back to their truck. All in all, it was an eight‑mile loop.

Gerrish loved nature, but he was not a serious outdoorsman. His brother Richard, who now lives in Scotland with his wife and four children, had spent years as an Outward Bound leader, guiding teenagers on adventures into the wilderness. Richard had also rappelled into some of the deepest caves in the world (including one in Austria called Fit for Insane Worms and Geckos). Gerrish, in contrast, was more of a weekend adventurer. The construction manager who worked with him renovating one of his houses called Gerrish and Chung “city folk,” pointing out that Gerrish would go to the store and get firewood rather than chopping his own.

As it happened, Gerrish called Richard the day before the hike for some parenting advice. Gerrish mentioned to his brother that he had been out exploring the property that day and that it had been unusually hot. Gerrish also mentioned that he was planning a family hike the next day to scout out possible swimming holes on the Merced River. Richard, who was well aware of the dangers of hiking in the heat, cautioned his brother, telling him to carry plenty of water and get an early start. Gerrish agreed, and promised they would be off the trail before it got too hot.

On Sunday morning, Gerrish and Chung were up at dawn. They skipped breakfast and gathered up their gear: hiking poles, baby carrier, diapers and sippy cup for Miju, and a leash for eight‑year‑old Oski, a big strong dog that was part Akita. For drinking water, Chung carried an Osprey hydration pack, which held 85 ounces (about two and a half quarts) of water. Gerrish wore dark shorts, a yellow T‑shirt, and tennis shoes. Chung wore hiking boots, spandex shorts, and a yellow tank top. They woke up Miju and dressed her in a short‑sleeved onesie and pink shoes. Then they loaded everything into their 2020 gray Ford Raptor, an off‑road version of the F‑150 pickup, and headed out for the five‑minute drive to the trailhead.

At about 7:30 a.m., a woman walking her dogs along Hites Cove Road, which was not much more than a narrow dirt track, saw their truck drive past and park at the trail‑ head. Gerrish took their first selfie of the family on the trail at 7:44 a.m. The temperature was in the midseventies, not humid, a warm but lovely morning. Under normal conditions, Gerrish might well have calculated that the eight‑mile loop might take four or five hours to complete. If all went well, they would be off the trail by 1 p.m., just as the afternoon sun began to blaze.

In recent years, climate‑driven heat and drought have turned the Sierra foothills into a tinderbox. The area was badly burned in the 2018 Ferguson Fire, which consumed almost a hundred thousand acres and forced Yosemite National Park to close for the first time in decades. Two firefighters died. The fire, caused by a spark from the catalytic converter of a vehicle, turned the dry grass and bark‑beetle‑infested trees into an inferno. In the three years since the fires, wildflowers had returned and a few saplings were rising out of the rocky soil, but most of the trees were charred sticks poking up at the sky and offering little shade for hikers or wildlife on a hot afternoon.

Even before the 2018 fire, the trail that Gerrish had selected for the hike was a risky choice. The steep ascent out of the canyon was along a southeastern‑facing slope, which meant it was exposed to the full brutality of the sun. “It’s a horrible trail,” one local wrote on social media. “With the poison oak, rattlesnakes, and potential for broken ankles, it just isn’t worth it.” Another local, who hiked the trail on a mild spring day, praised the wildflowers blooming on the mountainside, but noted that it was dangerously exposed: “I wouldn’t want to do this [hike] on a hot day.”

For Gerrish and his family, the hike started off easy. The first two miles were mostly downhill. The morning sun would have felt good, the light slanting across the mountains. It only took them a little over an hour to get to the river, where they stopped to take another family selfie at 9:05 a.m. They rambled along the river for the next hour and a half, where they may well have stopped for a drink from their hydration pack and even doused their hands and faces in the cool river water.

At 10:29 a.m., they took a final family selfie along the river, then began the climb. It had been three hours since they left the truck. The temperature had risen to nearly 100 degrees and it was getting hotter with each passing minute. The recently burned trees along the steep trail were black and leafless. The tall grass was sunburned to a golden, crispy brown, like straw.

If there is one idea in this book that might save your life, it is this: The human body, like all living things, is a heat machine. Just being alive generates heat. But if your body gets too hot too fast — it doesn’t matter if that heat comes from the outside on a hot day or the inside from a raging fever — you are in big trouble.

Every organism manages heat in a different way (more about that in an upcoming chapter). We humans work hard to maintain an internal temperature of about 98 degrees, no matter what the temperature is outside. If it is cold outside, we pull blood into our vital organs to keep them warm. If it is hot outside, we push blood toward our skin so it can be cooled by sweat. That’s why dry heat is often less dangerous than wet heat — the more humid the air is, the more difficult it is for our sweat to evaporate and dissipate heat. And like all living things, our bodies have thermal limits. Those limits vary depending on age, general health, and a number of other factors. But there is general consensus among researchers that a wet bulb temperature of 95 degrees — which basically means both outdoor air temperature and humidity levels are high (see glossary for a more precise definition of wet globe temperature) — is the upper end of human adaptability to humid heat. Beyond that, our body generates heat faster than it can dissipate it.

And that’s where trouble begins. Hyperthermia, or abnormally high body temperature, causes a range of physiological responses that might start with dizziness and heat cramps and lead all the way to heatstroke — a condition that can be, and often is, fatal.

Broadly speaking, there are two kinds of heatstroke: classic and exertional. Classic heatstroke hits the very young, the elderly, the overweight, and people suffering from chronic conditions like diabetes, hypertension, and cardiovascular disease. Alcohol and certain medications (diuretics, tricyclic antidepressants, antipsychotics) can increase one’s susceptibility. Classic heatstroke is often what happens to babies who are left in cars, or older people trapped in upper‑story apartments with no air‑conditioning on summer days.

Exertional heatstroke, on the other hand, often hits the young and fit. Exercise drastically accelerates temperature rise. Anytime you flex a muscle, it generates heat. In fact, when you move a muscle, only about 20 percent of the energy you expend actually goes to muscle contraction; the other 80 percent is released as heat. That is why marathon runners, cyclists, and other athletes sometimes push into what is called exercise‑induced hyperthermia, where internal body temperatures typically hit 100 to 104 degrees. Usually, there’s no lasting damage. But as your body temperature climbs higher, it can trigger a cascading disaster of events as your metabolism, like a runaway nuclear reactor, races so fast that your body can’t cool itself down.

There is a lot of confusion about the relationship between water and heat exhaustion and heatstroke. Water is necessary to keep sweat flowing. If you get dehydrated, you can’t sweat. And if you can’t sweat, you can’t cool off. But drinking water does not in itself cool off inner‑core body temperatures. Put another way, dehydration can exacerbate heat exhaustion and heatstroke, but you can still die of heatstroke and be well hydrated. In one study in Montana, a wildfire fighter working in extreme heat for a seven‑hour period who continuously drank a huge amount of water — more than twice as much as the firefighters around him — still had a core body temperature of 105 degrees, which is well into heatstroke‑land.

Sam Cheuvront, a heat and hydration expert who spent more than twenty years at the US Army Research Institute of Environmental Medicine in Massachusetts, put it to me this way: “Both heat exhaustion and heatstroke can occur in the absence of dehydration. We can speculate that proper hydration can, however, delay heat exhaustion because dehydration exacerbates heat exhaustion. But proper hydration cannot prevent heatstroke.”

Drinking water when it’s hot is certainly important. A common recommendation is about one half quart (16 ounces) of water per person per hour of moderate activity in moderate temperatures. But in extreme conditions, even that isn’t enough. A well‑hydrated human can sweat up to three quarts per hour, but no matter how much water you drink, your body can only replace about two quarts of water per hour — so if you are in a hot place for a long time, dehydration is a concern.

Even at a sweating rate of two quarts per hour, which is what a firefighter might do while working in a hot environment and wearing protective clothing, it takes an hour to exceed 2 percent dehydration, which is really where dehydration starts contributing to heart strain, mostly due to reduced blood volume. It also exacerbates the competition for blood flow between your muscle, your skin, your brain, and your organs.

The only effective treatment for heatstroke is to get a person’s core body temperature down, fast. A cold shower or bath, or tubs of ice, is one way to do this. Another is to quickly cool places on the body where, because of the structure of our veins, a lot of blood circulates close to the surface: the bottoms of the feet, the palms of the hands, the upper part of the face. Taking Tylenol or aspirin doesn’t help. In fact, both can interfere with kidney function, and make it harder for your body to deal with rising temperatures. Only after core body temperature is lowered do the damages from heatstroke stop and hope of repair and recovery begin.

About an hour and a half after Gerrish, Chung, Miju, and Oski left the banks of the Merced, they were in trouble. They had climbed two miles up the trail, but still had another mile and a half of steep switchbacks to go before they got back to their truck.

At 11:56 a.m., Gerrish pulled his phone out of his pocket and attempted to send a text: “[name redacted] can you help us. On savage lundy trail heading back to Hites cove trail. No water or ver [over] heating with baby.” Records would later show that the air temperature at that time was 107 degrees. But on the trail, with full sun and no shade and rocks absorbing and amplifying the heat, the actual temperature that Gerrish and his family were experiencing was certainly much higher.

Gerrish and Chung surely had a moment when they stopped to consider whether it was better to stop climbing and turn around and seek refuge by the river. There wasn’t a lot of shade down there either, but there was some. And they could have found some relief by wading out into the cool water. But at the same time, if they retreated to the river, they would still have to hike out eventually, and the afternoon was just going to get hotter. Waiting until the temperature dropped and the sun lost its edge meant waiting until late afternoon or early evening. While that might have been the safe decision, it had its own risks: they were out of water, and signs along the river warned hikers not to drink from it due to toxic algae. The actual risk of getting sick from toxic algae was extremely low compared to the danger of heatstroke, but Gerrish and Chung may not have known that.

There was also the issue of food for Miju. They had not brought enough diapers or baby formula with them for an entire day. Perhaps, out of love for Miju, they decided that it was better to suffer in the heat themselves, push through the climb back to the truck, blast the AC, and feel the relief of having escaped a heat‑driven nightmare.

The typo in Gerrish’s text message (“or ver”) may be nothing more than a sign that he was in a hurry to get the message out. But it also could be a sign that the heat was already causing him some cognitive difficulty, which is common during extreme heat exhaustion. If that was the case, it would make clear‑headed decision‑making about whether to keep climbing in the heat or seek refuge near the river all the more difficult.

Whatever he was thinking at that moment, Gerrish was clearly aware that their situation was growing more dire. Over the next twenty‑seven minutes, he attempted five phone calls, but because of the lack of service in the area, none went through. He did not call 911. If he had, there’s a chance he might have gotten a response, given that in remote areas, 911 calls are routed differently to cell towers and so are some‑ times picked up in areas where other calls are not. Gerrish may not have been aware of this, or he simply might have been too disoriented to consider it. In any case, he made one last attempt to call someone for help at 12:36 p.m. By then, two hours had passed since they left the shaded banks of the Merced.

No one knows the exact sequence of events that led to tragedy for the Gerrish family. But on a hot day, the road to heatstroke looks like this: As soon as you step outside, your blood grows warmer, heated by the sun’s radiation and your own rising metabolism. Keeping your core body temperature at around 98 degrees — the happy place for humans — now requires work. Receptors in the preoptic area of your brain’s hypothalamus start to fire, telling your circulatory system to push more blood toward your skin, where the heat can be dissipated. Your sweat glands begin to pump salty liquid from a tiny reservoir at the base of the gland up to the surface of your skin. You sweat. As the sweat evaporates, the heat is carried away. 

But the amount of heat your body can dissipate through sweat is limited. Your blood vessels dilate, trying to move as much overheated blood to the surface as possible. But if you don’t find a place to cool off, your core body temperature will rise quickly. And the harder you are working your muscles, the faster it will rise. Your heart pumps madly, trying to push as much blood as possible to your skin to cool off, but it can’t keep up. As your blood is shunted away from your core, your internal organs — your liver, your kidneys, your brain — become starved for blood and the oxygen it carries. You feel light‑headed. Your vision dims and narrows. As your core body temperature rises to 101 degrees, 102 degrees, 103 degrees, you feel wobbly — and due to the falling blood pressure in your brain, you will likely pass out. This is in fact an involuntary survival mechanism, a way for your brain to get your body horizontal and get some blood to your head.

At this point, if you get help and can cool down quickly, you can recover with little permanent damage.

But if you fall onto the ground in a place that is exposed to the sun and lie there, the dangers increase. It’s like falling into a hot frying pan. Ground temperatures can be twenty to thirty degrees above air temperature. Your heart becomes desperate to circulate blood and find a way to cool down. But the faster your heart beats, the more your metabolism increases, which generates more heat, which causes your heart to beat even faster. It’s a lethal feedback loop: As your internal temperature rises, rather than cranking up your air conditioner, your body fires up your furnace. If you have a weak heart, that might be the end for you.

At a body temperature of 105 to 106 degrees, your limbs are convulsed by seizures. At 107 and above, your cells themselves literally begin to break down or “denature.” Cell membranes — the thin lipid walls that protect the inner workings of your cells — literally melt. Inside your cells, the proteins essential to life — the ones that extract energy from food or sunlight, fend off invaders, destroy waste products, and so on — often have beautifully precise shapes. The proteins start as long strands, then fold into helixes, hairpins, and other configurations, as dictated by the sequence of their components. These shapes define the function of proteins. But as the heat rises, the proteins unfold and the bonds that keep the structures together break: first the weaker ones, and then, as the temperature mounts, the stronger ones. At the most fundamental level, your body unravels.

At this point, no matter how strong or healthy you may be, your odds of survival are slim. The tiny tubes in your kidneys that filter out waste and impurities in your blood are collapsing. Muscle tissues are disintegrating. You develop holes in your intestines, and nasty toxins from your digestive tract flow into your bloodstream. Amid all this chaos, your circulatory system responds by clotting your blood, cutting off its flow to vital organs. This triggers what doctors call a clotting cascade, which uses up all the clotting proteins in your blood and, paradoxically, leaves you free to bleed elsewhere. Your insides melt and disintegrate — you are hemorrhaging everywhere.

After the bodies of the Gerrish‑Chung family were airlifted off the mountain, Mariposa County Sheriff Jeremy Briese was faced with an obvious but perplexing question: What — or who — killed them? Families don’t just drop dead on hikes, especially families hiking with a young child. “There were no signs of trauma, no obvious cause of death. There was no suicide note,” Mariposa County Sheriff’s Office spokesperson Kristie Mitchell said. “They were out in the middle of a national forest on a day hike.”

Media interest was intense. The Mariposa County Sheriff’s Office parking lot was crowded with satellite trucks, and reporters were out hiking the trail, playing up the mystery of how the happy family could have died together on the trail.

“It could be a carbon monoxide situation. That’s one of the reasons why we’re treating it as a hazmat situation,” Mitchell explained. According to one theory, the family could have been killed by a sudden release of poisonous gas from a nearby abandoned mine. A lightning strike had been ruled out — there was not a cloud in the sky that day, and there were no burn marks on the bodies.

Investigators also considered the possibility of toxic algae in the Merced River. Water samples from several locations on the river tested positive for Anatoxin A, a cynobacteria that can be deadly to animals but has never caused any recorded deaths among humans. And there was no evidence that Gerrish, Chung, or their daughter had ingested any of the river water anyway. As for the idea of poisonous gas escaping from a mine, an old mine entrance was found two miles away, but law enforcement officials found no indication that the family had been anywhere near it.

Autopsy reports on Gerrish and Chung revealed little, as did a necropsy on Oski. Which is not surprising, because in most heat‑related cases, people die of organ failure, which does not leave an easily detectable signature. Sometimes, an autopsy can find signs of internal bleeding or liver or kidney damage. In the case of Gerrish and Chung, determining the cause of death was complicated by the fact that their bodies had remained on the trail for some time after their deaths and were not well‑preserved.

“I’ve never seen a death like this — they appeared to be a healthy family and a family canine,” Briese told reporters. “Our hearts go out to the family, and we are working hard to provide closure. We’re not going to rest until we figure this out.”

Investigators hoped to find some clues in Gerrish’s phone, but due to password protection, they couldn’t get access to the contents immediately and had to send it to the FBI for help.

Oski likely got into trouble first. Dogs are vulnerable to heat because they cannot sweat. As anyone who has ever taken a dog for a walk on a hot summer day knows, their only mechanism to release heat is panting, which is not particularly efficient. Oski was a large, muscular dog with a thick coat. Climbing a steep slope on a 100‑degree day would have been brutal.

One‑year‑old Miju would have felt the heat quickly too. She was in a carrier on her father’s back, which was not a cool place to be. Besides being inside a fabric backpack, which would have trapped heat like an additional layer of clothing, she was inevitably absorbing heat from both her father’s body and the sun. In addition, sweat glands in prepubescent children are not fully developed yet, which makes it difficult for them to release the heat that builds up in their bodies. Their bodies also contain a smaller volume of blood than adults’, so when their heart pumps blood to their skin to try to cool down, it takes blood away from internal organs, potentially damaging them. This is why babies are so vulnerable when left alone in hot cars. They are basically defenseless against heat. The heat would not have been easy for Gerrish either. He was a big guy, weighing about 210 pounds (“He had a dad‑bod,” his friend Steve Jeffe recalled fondly). Although all adult humans, no matter what sex or race, have about the same number of sweat glands, size is a disadvantage when trying to cool off, simply because a bigger animal carries a larger volume of heat in its body than a smaller animal. In addition, Gerrish was carrying Miju on his back, which added more weight, as well as inhibiting his ability to dissipate sweat.

Chung may have been in the best position to survive the climb. She was carrying only a light backpack with a hydration bladder and a few supplies for Miju. Given her smaller stature, she was likely slower to overheat.

“Ellen was in great shape,” one of her friends told me. “She exercised all the time. She didn’t have an ounce of fat on her. If anyone could survive this, you would think it would be her.”

On October 21, a little more than two months after Gerrish, Chung, Miju, and their loyal pal Oski set out for a hike on a summer morning, Sheriff Briese held a press conference to reveal the official findings of the investigation into their deaths. “The cause of death was hyperthermia and probable dehydration due to environmental exposure,” he said, voice trembling just a little. As in many heat‑related deaths, there was no single piece of evidence that caused investigators to conclude that hyperthermia was the killer. It was based on scene investigation, the circumstances of their deaths, and the reasonable exclusion of other causes. Briese showed a graphic of the area where the bodies were found, noting that the trail’s southern slope meant constant exposure to the sun and no shade. He estimated that the ground‑level air temperature along the trail while the family was hiking was as high as 109 degrees.

What happened to Gerrish and Chung and Miju and Oski was not just a consequence of bad luck and poor decision‑making in the wild. It was a tragedy that was shaped by our larger failure to reckon with the risks of life in a rapidly warming world, and with the nature of heat itself. We simply have not come to terms with it, especially in the way I am describing. It is not how anyone expects to die. In part, it’s because we live in a technologically advanced world where it’s all too easy to believe that the rough forces of nature have been tamed. But it’s also because our world is changing so fast that we can’t grasp the scale and urgency of the dangers we face.

In August 2022, more than a year after their deaths, family and friends gathered on a tranquil spot on one of Gerrish and Chung’s properties in Mariposa to bury their ashes. It was a beautiful clear Saturday morning. But it was also “slightly surreal,” Richard recalled. In the previous weeks, the area had been torched by the Oak Fire, which had burned 20,000 acres and 180 buildings and come within a half mile of Gerrish and Chung’s home. There were still fire trucks parked on the side of the roads and bulldozers burying the last smoldering embers. It was the second time in four years this area had badly burned.

As family and friends stood nearby, Richard and Chung’s sister Melissa placed a dark wooden box containing the commingled ashes of Gerrish, Chung, Miju, and Oski in the ground. Richard read from the journals of John Muir, who was born in Dunbar, Scotland, in 1838, not far from where Richard now lived. Muir’s exuberant writing about the California mountains had led to the founding of America’s national parks and inspired generations of people to think differently about their connection with nature. Muir was also a voice from a simpler time, when the biggest threat to his beloved Yosemite was a dam, not a fast‑warming climate. In the passage Richard chose, Muir described death as a “home‑ going”: “Myriads of rejoicing living creatures, daily, hourly, perhaps every moment sink into death’s arms,” Richard read. “Yet all enjoy life as we do, share Heaven’s blessings with us, die and are buried in hallowed ground, come with us out of eternity and return into eternity.”

Several other family members and friends read poems or offered remarks. Then Richard and Melissa covered the wooden box with a few shovelfuls of dirt and tamped it down. To the east, in the distance, the granite dome of El Capitan loomed. It wasn’t noon yet, but already the heat was rising.

The Heat Will Kill You First comes out Tuesday, July 11. You can preorder a copy here.

Excerpted from the book THE HEAT WILL KILL YOU FIRST by Jeff Goodell. Copyright © 2023. Available from Little, Brown and Company, a division of Hachette Book Group Inc., New York, NY, USA. All rights reserved.