by Bryan Walsh
All of this is speculation, because we still know so little about the universe that surrounds us, and our place in it. So we search on. “The first evidence of extraterrestrial intelligence may come to us from the remains of less prudent civilisations,” Stevens, Forgan, and O’Malley-James write in the conclusion of their paper on necrosignatures. “In doing so, such information will bring us not only knowledge, but wisdom.”62
Knowledge, yes; wisdom, I’m less sure of. SETI pioneers believed that the discovery of extraterrestrial intelligence would kindle hope that we could survive what Sagan termed our “technological adolescence.” Perhaps the aliens, like friendly older siblings, would even guide us through that transition. But the discovery of dead civilizations—if coupled with a continued failure to make contact with any living alien intelligences—would tell us that we may instead be fated to destruction. That last variable in the Drake equation—the life span of a species—would be revealed, and we would know that the reason we seem to be alone in the universe is that the alien civilizations we might share this universe with have died off. And perhaps so will we.
SURVIVAL
The Day After
Everyone wants to save the world, and almost every time we tell a story about the end of the world, that’s precisely what happens. At the last moment our heroes defuse the countdown to nuclear annihilation, or invent the vaccine to stop the killer disease, or triumph over a malevolent army of machines or an invading horde of aliens. And so it has been in our actual brushes with end times. Sometimes heroes like Vasili Arkhipov made impossible decisions that prevented global catastrophe. More often, we’ve simply been lucky. But every time the world has come close, the apocalypse has been postponed. So far.
When I set out to write this book, I hoped that it would play some part, however small, in encouraging us to do what can be done to prevent existential catastrophes—in other words, to save the world, for my child and for all the children of the future. I believe we can. For most of our existence, humanity’s survival was indeed a matter of luck, our good fortune—or our anthropic shadow—the main reason we didn’t go extinct like nearly every other species in this planet’s history. No longer. Now whether we endure or die will come down chiefly to our own decisions, to whether our wisdom is equal to the task of saving ourselves—including from ourselves.
Even the wisest versions of ourselves, however, will get something wrong eventually. Spool out the tape of the future far enough and a global catastrophe will occur. It might be the nuclear war we’ve dreaded. It might be a supervolcano that we can’t predict. It might be the virus, hatched in nature or the lab, that burns through humanity. The doomsayers are always right, eventually. Sooner or later, winter will come.
But the end isn’t the end—or at least, it doesn’t have to be. A handful of existential threats—like the sudden rise of a hostile AI superintelligence or an asteroid even larger than the one that wiped out the dinosaurs—would be so massive and strike so quickly that they would leave no one behind. Other global disasters, though, would become existential only if we let them. Survival is the difference between mere catastrophe and extinction—and that distinction is all that matters. Existential risk is a game played with permanent stakes. If we can survive and rebound from disaster, no matter how severe, our story will go on, and that disaster may end up as a historical footnote, just like the Toba supereruption tens of thousands of years ago. But if we can’t survive, our story is over—forever.
What energy we manage to marshal on existential risk is largely spent on preventing disasters before they ever occur, however, not preparing for the awful aftermath. That makes a kind of emotional sense—who wants to contemplate the last, slow dying of their world? But it leaves us vulnerable to what the U.S. military calls “right of boom”—the seconds and days and years after a catastrophe.1 We need not just prevention in the face of the worst to come, but resilience.
Everyone wants to save the world. But it may be that the most important work we can do now is to prepare ourselves for the day when we fail to save the world—and ensure there’s a plan to pick up the pieces.
In the first seven days after Donald Trump’s election in 2016, 13,401 Americans registered with the immigration authorities in New Zealand.2 This was not because they all had a burning desire to see the locations of the Lord of the Rings trilogy. New Zealand—remote, English-speaking, bucolic, and did I mention remote?—has become the backyard fallout shelter for the superrich, an entire nation reachable by private plane where our plutocrats can hole up in the event of a major catastrophe. New Zealand is for the survivalism of the elite what the Grand Caymans have long been for their bank accounts. Tech titans like Peter Thiel have purchased estates in New Zealand for the express purpose of surviving the apocalypse. Thiel even went so far as to secure New Zealand citizenship after spending just twelve days in the country.3
The boom market in New Zealand boltholes is a perfect expression of an age when the rich lay claim to more of everything—including the life jackets. But it’s not only the ultrawealthy who have plans for surviving the worst. In 2017, two-thirds of Americans reported stockpiling supplies to survive a natural disaster.4 More than three million Americans calls themselves doomsday preppers,5 meaning they are actively preparing to survive not just run-of-the-mill natural disasters but also world-ending calamities. They connect through organizations like the American Preppers Network and read magazines like Recoil OffGrid. There are prepper podcasts and prepper blogs and the Self-Reliance Expo, a national conference for preppers. There are tips for doomsday prepping with children and prepper gift ideas for Father’s Day, like the Stovetec Rocket Stove, which is a great tool for cooking in the event of the total collapse of the electrical grid—or, alternately, for tailgating.6
A survey by the National Geographic Channel found that 40 percent of Americans thought that preparing a bomb shelter or stocking up on supplies was a better investment than funding a 401(k).7 And if you’re part of that 40 percent, there are plenty of places that will take your money. You can buy a luxury bunker from a company called Vivos for $20,000 to $50,000, including in a former army munitions depot in South Dakota that is billed as the “largest survival community on Earth.”8 If you’d rather wait out the apocalypse at home, Atlas Survival Shelters—which has been selling bomb shelters since the Cold War—will build you a personal doomsday habitat. It’s a mere half a million for the concrete dome version,9 though you might not have much left over for the $4,995 Prepster Black Ultra Luxe Emergency Bag. That would be a shame, because you’d miss out on the toiletries from Malin+Goetz, the Marvis toothpaste, and the Mast Brothers chocolate bars.10 What are the end times, after all, without artisanal candy?
There’s real fear at play in these trends, and as I’ve shown throughout this book, much of that fear is justified. But instead of rolling up our sleeves and tackling the collective challenge of existential risk, we seem to prefer indulging in individualist survivalist measures. Each of us should set aside supplies to endure a natural or man-made disaster that disrupts the flow of water or food for several days. Extra medicines, a go bag, photocopies of important documents—everyone should have them handy. A survival plan that focuses solely on individuals and families, however, won’t be sufficient in the face of an existential catastrophe. It might fit the self-reliant American character—or at least our idealization of it—but it is perverse that the same country that leads the world in doomsday prepperness has proven criminally unwilling to help its most vulnerable citizens after disasters like the 2017 Puerto Rico hurricane, and criminally incapable of addressing long-term threats like climate change.
At least some of the failure of the United States to plan nationally for major catastrophes may be a legacy of grand Cold War–era civil defense plans for nuclear war that overpromised and underdelivered. Between the mid-1950s and the late 1960s, some 7,000 volunteers participated in more than 22,000 man-days living in emergency shelters that ranged from family size
to over 1,000 people. The tests led to the development of national standards for underground shelters meant to help Americans survive a nuclear holocaust. (Those standards allotted just 10 square feet of room per person—barely more than three times the space allotted to prisoners in the Nazis’ Bergen-Belsen concentration camp, a comparison the U.S. government itself made, for some reason.)11 But the shelters—or the Eisenhower administration’s admonishment to Americans to keep an emergency food stash officials called “Grandma’s Pantry”—would have been of little use in the event of a full-scale nuclear overkill, as Americans themselves eventually began to realize.
Once it had become clear to even the most hawkish national security officials that the survivors would envy the dead after a nuclear war between the United States and the Soviet Union, earnest plans for civil defense became a punch line. Those opposed to nuclear weapons thought that exposing the absurdity of civil defense would underscore the madness of nuclear war—and they were right. But today, instead of preparing as a society for nuclear war and other existential threats, most of us simply choose to ignore the risk, while a minority of survivalists and preppers obsess over it, plotting how they and their families can outlast the apocalypse.
It’s wrong to assume that national survival and civil defense plans are pointless, but it’s just as wrong to believe that an individual prepper could endure a global existential catastrophe on their own, no matter how well prepared—or rich—they are. “Being human is not about individual survival or escape,” as the media theorist and writer Douglas Rushkoff put it. “It’s a team sport. Whatever future humans have, it will be together.”12 That has to include survival as well.
Three of the existential catastrophes covered in this book—a supervolcano eruption, an asteroid strike, and nuclear war—share a common killing method: rapid climate cooling, mostly through a long-lasting and planet-wide reduction in sunlight. The initial detonations or impact or eruption will kill tens of millions instantly, but the extinction blow would be global starvation. The food chain as we know it begins with sunlight. Blot out the sun, and even the best-prepared survivalist, a master of the wilderness, will starve to death along with everyone else once the existing global food supply runs out, perhaps in as little as a year.13 “There would be chaos, a total breakdown of cities,” David Denkenberger told me. “We’d basically lose industrial civilization.”
If we’re going to prevent human collapse and even extinction after a sun-blocking catastrophe, we’re going to need to feed ourselves without the sun, potentially for years. Fortunately, Denkenberger has some ideas. A civil engineer at Tennessee State University, Denkenberger is the coauthor of the book Feeding Everyone No Matter What: Managing Food Security After Global Catastrophe. Like a lot of scholars in the existential risk community, Denkenberger sought to find a neglected research area where his work could make a difference to the future of the human race. He settled on postcatastrophe food supplies—in part because very little research had been done on the subject—but quickly realized that simply storing enough backup food to feed the world would be impossible. To keep all 7-plus billion people fed for the years it would take normal sunlight to return would require so many barrels of food that they could be stacked from the Earth to the moon—forty times over. It would also cost more than $10 trillion,14 about one-tenth of global GDP,15 and take food from the mouths of the more than 800 million people who already have too little to eat.
Denkenberger understood that to survive, we’d need to get very creative, both in terms of the food we’d raise and the food we’d be willing to eat. He became inspired when he learned that after the dinosaurs were wiped out, one species thrived in the cold and dark and death that followed: fungi. “Well, maybe when humans go extinct the world will be ruled by fungi again,” Denkenberger told me. “And then I thought, ‘Why don’t we just eat the mushrooms and not go extinct?’”
Those mushrooms are key. Trillions of trees will die in the aftermath of a climate-cooling global catastrophe. Those trees are of little direct use to human beings, since we can’t digest cellulose. But mushrooms can, and by raising mushrooms on the dead trees, we can transform the caloric energy trapped in the trees into something humans can actually eat. A log roughly 3 feet long and 4 inches in diameter should produce 2.2 pounds of wet mushrooms over the course of four years. Not a lot, but if we’re ruthlessly efficient—and, quite realistically, if the global population has already been thinned by the initial disaster—mushrooms might provide enough food to help us survive.16 “You can use people to grow mushrooms on trees and harvest the leaves, grind them up and get human food out of it,” said Denkenberger. “The ground-up leaves could be made into tea to provide missing nutrients like vitamin C, or fed to ruminant animals like cows. Or rats.”
Yes, rats. What cellulose that isn’t digested by fungi could be fed to rats, which in turn could be fed to us. Some humans already eat rats, but the current global population of rats would only be enough to provide 0.1 percent of our current food requirements. But the good—or perhaps horrifying—news is that rats grow to sexual maturity in just six weeks, and give birth to seven to nine offspring every seventy days. Rats don’t need or even particularly like sunlight, so a blocked sun shouldn’t stunt their growth.17 If everything goes to plan, Denkenberger believes that it would take approximately two years until there were enough rats to provide 100 percent of human food.18 “Furthermore,” he and his coauthor Joshua Pearce write, “other rodents would provide additional food.”
And then there are the insects. Eating bugs may seem repulsive to many of us, but more than two billion people globally are entomophagists, meaning they consume insects.19 In countries like Mexico and Thailand food markets are stocked with commercially raised water beetles and bamboo worms. Insects are a highly sustainable source of protein—it takes far less water to raise a third of a pound of grasshoppers than the 869 gallons needed to produce the same amount of beef. A 3.5-ounce portion of cooked Usta terpsichore caterpillars—commonly eaten in Central Africa—contains about 1 ounce of protein, slightly more than you’d get from the same amount of chicken. Water bugs have four times as much iron as beef.20 And they are abundant—by one estimate the total weight of the world’s insect population is 70 times that of the human population.21 Nature is very good at making insects.
The same qualities that make insects so abundant and so persistent would allow many species to weather even the most extensive, climate-changing existential catastrophes. Beetles can feast on dead wood, and humans can feast on beetles. But would we? I once attended an insect food fair in Richmond, Virginia, for a Time magazine story. There I sampled Orthopteran Orzo, a pasta dish with ground cricket serving as the meatballs, as well as the popcorn-sized larvae of deep-fried mealworms. They were both passable, but it might actually take the end of the world for me to eat the tarantula tempura, a battered, fist-sized arachnid on a plate that I can still see in my nightmares.22
If I were starving, though, I’d manage. As Denkenberger and Pearce write: “We believe hunger would likely overwhelm humanity’s current arbitrary selective tastes given a serious crisis.”23 If that still sounds awful, our diet would be even worse if we failed to prepare for a disaster and food stores ran low before we could ramp up mushroom and rat production. We would be forced to rely on the very bottom rung of the food chain: bacteria. There are species of bacteria that can feed on natural gas, and we could feed on the bacteria once it is run through a process of pasteurization. The advantage is that bacteria can double every twenty minutes—faster even than rats—which means that the microbes could theoretically provide 100 percent of human food needs in just two months.24 As for the taste, well, it’s as appetizing as it sounds, Denkenberger said, although he noted that we already consume supplements like spirulina. “People call [the nutritional supplement] spirulina algae, but it’s actually a form of bacteria.”
Denkenberger has more ideas, including ideas about what won’t work—like trying to create
vast indoor farms powered by artificial sunlight. (The conversion rate from fossil fuels to electricity to artificial lights to crops is so low that even if we devoted all the electricity in the world to indoor farms, we would be able to provide only about 5 percent of global food demand.) But more than ideas, Denkenberger has a rationally optimistic vision of how we should respond to what would be the most terrible test our species may ever face. We will survive—we will endure—only if the survivors pull together. “If you want to save everyone, then it certainly has to be large-scale cooperation,” he said.
This notion—that we would unite in a moment when everything falls apart—goes against what we’ve been told will happen after the collapse, everything that survivalists are preparing to survive. Ask most people to picture the aftermath of a horrifying catastrophe that kills billions and blocks out the sun for years, and you’ll get something like Cormac McCarthy’s novel The Road, a story where civilization and government have utterly collapsed, leaving the survivors in a world where suicide seems to be the best option and cannibalism is practiced. (About cannibalism: In 2017 a group of students at the University of Leicester decided to calculate how long the human race would last if humans only had other humans to eat. They found that one person would remain after 1,149 days—though the researchers noted that the lone survivor would be at risk from contracting prion diseases, “which,” they wrote, “you get from eating human brains.”25)
