Scatter, Adapt, and Remember: How Humans Will Survive a Mass Extinction

HUMANITY IS AT a crossroads. We have ample evidence that Earth is headed for disaster, and for the first time in history we have the ability to prevent that disaster from wiping us out. Whether the disaster is caused by humans or by nature, it is inevitable. But our doom is not. How can I say that with so much certainty? Because the world has been almost completely destroyed at least half a dozen times already in Earth’s 4.5-billion-year history, and every single time there have been survivors. Earth has been shattered by asteroid impacts, choked by extreme greenhouse gases, locked up in ice, bombarded with cosmic radiation, and ripped open by megavolcanoes so enormous they are almost unimaginable. Each of these disasters caused mass extinctions, during which more than 75 percent of the species on Earth died out. And yet every single time, living creatures carried on, adapting to survive under the harshest of conditions.

My hope for the future of humanity is therefore not simply a warm feeling I have about how awesome we are. It is based on hard evidence gleaned from the history of survival on Earth. This book is about how life has survived mass extinctions so far. But it is also about the future, and what we need to do to make sure humans don’t perish in the next one.

During the last million years of our evolution as a species, humans narrowly avoided extinction more than once. We lived through harsh conditions while another human group, the Neanderthals, did not. This isn’t just because we are lucky. It’s because as a species, we are extremely cunning when it comes to survival. If we want to survive for another million years, we should look to our history to find strategies that already worked. The title of this book, Scatter, Adapt, and Remember, is a distillation of these strategies. But it’s also a call to implement them in the future, by actively taking on the project of human survival as a social and scientific challenge.

In the near term, we need to improve one of humanity’s greatest inventions, the city, to make urban life healthier and more environmentally sustainable. Essentially, we need to adapt the metropolis to Earth’s current ecosystems so that we can maintain our food supplies and a habitable climate. But even if you’re not worried about climate change, Earth is still a dangerous place. At any time, we could be hit by an asteroid or a gamma-ray burst from space. That’s why we need a long-term plan to get humanity off Earth. We need cities beyond the Blue Marble, oases on other worlds where we can scatter to survive even cosmic disasters.

But none of this will be possible if we don’t remember human history, from our earliest ancestors’ discovery of fire to our grandparents’ development of space programs. Fundamentally, we are a species of builders and explorers. We’ve survived this long by taking control of our destiny. If we want to survive the next mass extinction, we can’t forget how we got here. Now let’s forge ahead into the future that we’ll build for ourselves, our planet, and the humans who will exist a million years from now.

Evidence for the Next Mass Extinction

Over the past four years, bee colonies have undergone a disturbing transformation. As helpless beekeepers looked on, the machinelike efficiency of these communal insects devolved into inexplicable disorganization. Worker bees would fly away, never to return; adolescent bees wandered aimlessly in the hive; and the daily jobs in the colony were left undone until honey production stopped and eggs died of neglect. In reports to agriculture experts, beekeepers sometimes called the results “a dead hive without dead bodies.” The problem became so widespread that scientists gave it a name—Colony Collapse Disorder—and according to the U.S. Department of Agriculture, the syndrome has claimed roughly 30 percent of bee colonies every winter since 2007. As biologists scramble to understand the causes, suggesting everything from fungal infections to parasites and pollution, farmers worry that the bee population will collapse into total extinction. If bees go extinct, their loss will trigger an extinction domino effect because crops from apples to broccoli rely on these insects for pollination.

At the same time, over a third of the world’s amphibian species are threatened with extinction, too, leading many researchers to call this the era of amphibian crisis. But the crisis isn’t just decimating bees and frogs. The Harvard evolutionary biologist and conservationist E. O. Wilson estimates that 27,000 species of all kinds go extinct per year.

Are we in the first act of a mass extinction that will end in the death of millions of plant and animal species across the planet, including us?

That’s what proponents of the “sixth extinction” theory believe. As the term suggests, our planet has been through five mass extinctions before. The dinosaur extinction was the most recent but hardly the most deadly: 65 million years ago, dinosaurs were among the 76 percent of all species on Earth that were extinguished after a series of natural disasters. But 185 million years before that, there was a mass extinction so devastating that paleontologists have nicknamed it the Great Dying. At that time, 95 percent of all species on the planet were wiped out over a span of roughly 100,000 years—most likely from megavolcanoes that erupted for centuries in Siberia, slowly turning the atmosphere to poison. And three more mass extinctions, some dating back over 400 million years, were caused by ice ages, invasive species, and radiation bombardment from space.

The term “sixth extinction” was coined in the 1990s by the paleontologist Richard Leakey. At that time, he wrote a book about how this new mass extinction began 15,000 years ago, when the Americas teemed with mammoths, as well as giant elk and sloths. These turbo-vegetarians were hunted by equally large carnivores, including the saber-toothed cat, whose eight-inch fangs emerged from between the big cat’s lips, curving to well beneath its chin. But shortly after humans’ arrival on these continents, the megafauna populations collapsed. Leakey believes human habitat destruction was to blame for the extinctions thousands of years ago, just as it can be blamed today for the amphibian crisis. Leakey’s rallying cry has resulted in sober scientific papers today, where respected biologists detail the evidence of a mass extinction in the making. The New Yorker’s environmental journalist Elizabeth Kolbert has tirelessly reported on scientific evidence gathered over the past two decades corroborating the idea that we might be living through the early days of a new mass extinction.

Though some mass extinctions happen quickly, most take hundreds of thousands of years. So how would we know whether one was happening right now? The simple answer is that we can’t be sure. What we do know, however, is that mass extinctions have decimated our planet on a regular basis throughout its history. The Great Dying involved climate change similar to the one our planet is undergoing right now. Other extinctions may have been caused by radiation bombardment or stray asteroids, but as we’ll see in the first section of this book, these disasters’ most devastating effects involved environmental changes, too.

My point is that regardless of whether humans are responsible for the sixth mass extinction on Earth, it’s going to happen. Assigning blame is less important than figuring out how to prepare for the inevitable and survive it. And when I say “survive it,” I don’t mean as humans alone on a world gone to hell. Survival must include the entire planet, and its myriad ecosystems, because those are what keep us fed and healthy.

There are many ways we can respond to the end of the world as we know it, but our first instincts are usually paralysis and depression. After all, what can you do about a comet hurtling towards us through space, unless you’re Bruce Willis and his crack team of super-astronauts on a mission to blow that sucker up with a bunch of nukes? And what can you do to stop global environmental changes? This kind of “nothing can be done” response is completely understandable, but it rarely leads to pragmatic ideas about how to save ourselves. Instead, we are left imagining what the world will be like without us. We try to persuade ourselves that maybe things really will be better if humans just don’t make it.

I’m not ready to give up like that, and I hope you aren’t either. Let’s assume that humans are just getting started on their long evolutionary trek through time. How do we switch gears into survival mode?

Survivalism vs. Survival

Many of us already have concrete ideas about how we’d survive a disaster. Survivalist groups build shelters stocked with food, preparing for everything from nuclear attack to super-storms. Most of us are survivalists in small ways, too, even if we don’t build elaborate mountain hideaways. I live in San Francisco, where it’s common for people to keep big jugs of water and food supplies in our homes just in case we’re hit with a major earthquake. Our city government recommends that we all stash away enough supplies for a week, including fuel and water-purification tablets. Living here, I’m always aware of the possibility that my city might be in ruins tomorrow. It’s such an ever-present danger that I’ve worked out a quake contingency plan with my family: If a large quake hits and we can’t reach each other by phone, we’re going to meet in the southwest corner of Dolores Park, an open area that’s likely to be relatively safe and undamaged. We picked this location partly because over 100 years ago, people who survived San Francisco’s last great quake met in Dolores Park, too.

One reason I decided to write this book is that I’ve spent so much time thinking about future disasters. I don’t just mean the quake that’s going to wreck my home. For most of my life I’ve been obsessed with stories about the end of the world. The whole thing probably started with the Godzilla movies I watched as a kid with my dad, but by the time I was an adult I’d consumed every story about the apocalypse I could get my hands on, from cheesy movies like Hell Comes to Frogtown to literary novels like Margaret Atwood’s Oryx and Crake. When I was getting my Ph.D. in English, I wrote my dissertation on violent monster stories, exploring why people are drawn to the same tales of disaster over and over again. Eventually I left academia to become a science journalist, which didn’t exactly curb my appetite for destruction. I produced stories about everything from computer hacking to pandemics. While I was at MIT doing a Knight Science Journalism fellowship, I was first exposed to the idea that planetwide mass extinction is a vital part of Earth’s history, and an inevitable part of our future, too. Everything I had read in the fields of fiction and science led me to a single, dark conclusion. Humans are screwed, and so is our planet.

And so, a few years ago, I set out to write a book about how we are all doomed. I even printed out a brief outline of what I would research, then scribbled at the bottom: “Life is still nasty, brutish and short.” With this idea in mind, I immersed myself in the scientific literature on mass extinction. But soon I discovered something I didn’t expect—a single, bright narrative thread that ran through every story of death. That thread was survival. No matter how horrific things got, in geological and human history, life endured. I began to experience a kind of guarded optimism; perhaps billions of creatures would die in the coming mass extinction, but some would live. I reexamined my assumptions, and started to research what it would take for humans to be part of that bright narrative thread. I interviewed over a hundred people in fields from physics and geology to history and anthropology; I read about survival strategies in scientific journals, engineering manuals, and science-fiction novels; and I traveled all over the world to find evidence of humans’ quest to survive in ancient cities and modern-day labs. I emerged from my research with the belief that humanity has a lot more than a fighting chance at making it for another million years.

Human beings may be experts at destroying life, including our own, but we are also tremendously talented at preserving it. For all the stories about human selfishness and bloodlust, there are just as many about people putting themselves in mortal danger to rescue strangers from burning houses or oppressive governments. Our urge to live spills over onto everything else around us: We don’t want to live alone. During terrible disasters, we try to save as many other creatures as possible when we save ourselves. The urge to survive, not just as individuals but as a society and an ecosystem, is built into us as deeply as greed and cynicism are. Perhaps even more deeply, since the quest for survival is as old as life itself.

It’s hard to convey in words what it’s like to experience a change of heart based on gathering scientific evidence. I found hope in the historical accounts of human survival that Rebecca Solnit presents in A Paradise Built in Hell: The Extraordinary Communities That Arise in Disaster, and I found a scientific basis for that hope in Joan Roughgarden’s The Genial Gene: Deconstructing Darwinian Selfishness. These thinkers and many more suggest we possess the cultural and evolutionary drive to help each other survive. Put another way, I gained a new appreciation for movies like The Avengers, where our heroes unite to save the world.

All survival strategies, however small, are signs that we harbor hope about the future. The problem is that most of our strategies, like my earthquake plan, are focused on personal survival. I’m only prepared to help myself and a few close companions make it through the coming disaster. Stashing away a week’s worth of canned goods isn’t a plan that scales well for an entire planet and all the human civilizations on it. Though it’s not a bad idea to stock shelters with supplies for our families, we aren’t going to survive a mass extinction that way. Our strategies need to be much bigger.

We have to move from survivalist tactics, aimed at protecting individual lives in a disaster, to survival strategies that could help our entire species make it through a mass extinction.

Learning from the Past

Though this shift in strategy sounds like a daunting task, we can take comfort in knowing that our early ancestors faced near-extinction too. In part one of this book, we’ll plunge into geological deep time, and explore how life has endured through some of the most terrifying mass extinctions that have hit the planet over the past billion years. Then, in part two, we’ll turn to the history of human evolution, and all its perils. Some anthropologists believe Homo sapiens struggled through a population bottleneck that brought our numbers down to thousands of individuals less than 100,000 years ago—possibly due to climate change, or simply from the hardships we faced as we migrated out of Africa. Regardless of what caused the population bottleneck, both the fossil record and genetic analysis suggest that humans were at one time rather sparse upon the Earth. To survive, we adopted strategies similar to other species that lived through centuries of poison skies and gigantic explosions. And one of those basic strategies was adaptability.

“Adaptability” is a term you hear a lot from people who study mass extinction. They talk about it with a weird, gallows-humor kind of optimism. This is evident when you meet Earth scientist Mike Benton, who has spent the past ten years studying the Great Dying and its survivors. In his line of work, Benton has sifted through the remains of some serious planetwide horrors. Two hundred and fifty million years ago, when the Great Dying happened, megavolcanoes fouled the atmosphere with carbon, and it’s possible that an asteroid hit the planet, too. Despite Benton’s intimate familiarity with mass death, he still maintains hope that our species will survive. He told me that “good survival characteristics for any animal” include being able to eat a lot of different things and live anywhere, just as humans can. Of course, he noted, that doesn’t mean there won’t be a lot of casualties. He continued:

We have a fighting chance because our population is large, plus we can adapt to new territories and eat a wide range of things. That’s a good start, but what does it really mean to fight through? In part three of this book, we’ll look at some specific examples of how humans and other creatures have used the three survival strategies of scattering, adapting, and remembering. We’ll also explore how humans survive by planning for the future through storytelling. Fiction about tomorrow can provide a symbolic map that tells us where we want to go.

Stories of the Future

So where, exactly, do we want to go? With parts four and five, we’ll launch ourselves into humanity’s possible future. One of our biggest problems as a species today is that we have become so populous that our mass societies are no longer adaptive. Over half the population lives in cities, but cities can become death traps during disasters, and they are breeding grounds for pandemics. Worse, they are not sustainable; cities’ energy and agricultural needs are outpacing availability, which limits their life spans and those of the people in them. Part four is about several ways we’ll want to change cities over the next century to make them healthy, sustainable places that preserve human life as well as the life of the environment.

Often, a city-saving idea can start in a lab. Right now, in a cavernous warehouse on the Oregon State University campus, a group of researchers is designing the deadliest tsunami in history. In this cold, windy laboratory, they’ve got a massive water tank, about the size of an Olympic swimming pool, whose currents are controlled by a set of paddles bigger than doors. In the tank, wave after wave buffets a very detailed model city, washing away tiny wooden houses. Whirling in the water are special particles that can be tracked by hundreds of motion detectors, which help scientists understand tsunami behavior. At the tsunami lab, civil engineers destroy cities to figure out the best places for flood drains and high-ground emergency pathways in coastal cities.

Thousands of kilometers across the country, a revolutionary group of architects is working with biologists to create materials for “living cities” that are environmentally sustainable because they are literally part of the environment. These buildings might have walls made from semipermeable membranes that allow air in, along with a bit of rainwater for ceiling lights made from luminescent algae. Urbanites would grow fuel in home bioreactors, and tend air-purifying mold that flourishes around their windows. Unlike today’s cities, these living cities will run on biofuels and solar energy. These are the kinds of metropolises where we and our ecoystems could thrive for millennia.

In part five, we’ll look to the far future of humanity and think about our long-term plan to keep our species going for another million years. We know that when early humans were threatened with extinction they fanned out across Africa in search of new homes, eventually leaving the continent entirely. This urge to break away from home and wander has saved us before and could save us in the future. If we colonize other planets, then we will be imitating the survival strategy of our ancestors. Scattering to the stars echoes our journey out of Africa—and it could be our best hope for lasting through the eons.

Engineers at NASA are already preparing more robotic missions to the Moon, nearby asteroids, and Mars, hoping to learn about how the water we’ve discovered on other worlds could sustain a human colony. Every year since 2006, an international group of scientists and entrepreneurs holds a meeting in Washington State to plan for a space elevator that they hope to build in the next few decades. Such a project would allow people to leave Earth’s gravity while using a minimum of energy, thus making travel off-world more economically feasible (and less environmentally damaging) than with rockets. Other groups are figuring out ways to reengineer our entire planet to slow the release of greenhouse gases and grow enough food for our booming population.

These projects, designed to improve cities on Earth while paving the way for life on other worlds, are just a few examples of how humans are getting ready for the inevitable mega disasters that await us. They are also powerful evidence that we want to help each other survive.

Human beings also have one survival skill that we’ve yet to find in creatures around us. We can pass on stories of how to cope with disaster and make it easier for the next group who confronts it. Our tales of survival pass over borders and travel through time from one generation to the next. Humans are creatures of culture as well as nature. Our stories can offer us hope that we’ll make it through unimaginable troubles to come. And they can inspire scientific research about how we’ll do it. Call them tales of pragmatic optimism.

This book is full of such tales—stories about people whose pragmatic optimism could one day save the world. Scientists, philosophers, writers, engineers, doctors, astronauts, and ordinary people are working tirelessly on world-changing projects, assuming that one day our lives can be saved on a massive scale. As their work comes to fruition, our world becomes a very different, more livable place.

If humans are going to make it in the long term, and preserve our planet along with us, we need to accept that change is the status quo. To survive this far, we’ve had to change dramatically over time, and we’ll have to change even more—remolding our world, our cities, and even our bodies. This book is going to show you how we’ll do it. After all, the only reason we’re here today is because thousands of generations of our ancestors did it already, to make our existence possible.