The Precipice: Existential Risk and the Future of Humanity

Toby Ord

Copyright 2020 Hachette Books. (Kindle Edition.)
Pages 1–19 excerpted for GESM 120.


If all goes well, human history is just beginning. Humanity is about two hundred thousand years old. But the Earth will remain habitable for hundreds of millions more—enough time for millions of future generations; enough to end disease, poverty and injustice forever; enough to create heights of flourishing unimaginable today. And if we could learn to reach out further into the cosmos, we could have more time yet: trillions of years, to explore billions of worlds. Such a lifespan places present-day humanity in its earliest infancy. A vast and extraordinary adulthood awaits.

Our view of this potential is easily obscured. The latest scandal draws our outrage; the latest tragedy, our sympathy. Time and space shrink. We forget the scale of the story in which we take part. But there are moments when we remember—when our vision shifts, and our priorities realign. We see a species precariously close to self-destruction, with a future of immense promise hanging in the balance. And which way that balance tips becomes our most urgent public concern.

This book argues that safeguarding humanity’s future is the defining challenge of our time. For we stand at a crucial moment in the history of our species. Fueled by technological progress, our power has grown so great that for the first time in humanity’s long history, we have the capacity to destroy ourselves—severing our entire future and everything we could become.

Yet humanity’s wisdom has grown only falteringly, if at all, and lags dangerously behind. Humanity lacks the maturity, coordination and foresight necessary to avoid making mistakes from which we could never recover. As the gap between our power and our wisdom grows, our future is subject to an ever-increasing level of risk. This situation is unsustainable. So over the next few centuries, humanity will be tested: it will either act decisively to protect itself and its longterm potential, or, in all likelihood, this will be lost forever.

To survive these challenges and secure our future, we must act now: managing the risks of today, averting those of tomorrow, and becoming the kind of society that will never pose such risks to itself again.

It is only in the last century that humanity’s power to threaten its entire future became apparent. One of the most harrowing episodes has just recently come to light. On Saturday, October 27, 1962, a single officer on a Soviet submarine almost started a nuclear war. His name was Valentin Savitsky. He was captain of the submarine B-59—one of four submarines the Soviet Union had sent to support its military operations in Cuba. Each was armed with a secret weapon: a nuclear torpedo with explosive power comparable to the Hiroshima bomb.

It was the height of the Cuban Missile Crisis. Two weeks earlier, US aerial reconnaissance had produced photographic evidence that the Soviet Union was installing nuclear missiles in Cuba, from which they could strike directly at the mainland United States. In response, the US blockaded the seas around Cuba, drew up plans for an invasion and brought its nuclear forces to the unprecedented alert level of DEFCON 2 (“Next step to nuclear war”).

On that Saturday, one of the blockading US warships detected Savitsky’s submarine and attempted to force it to the surface by dropping low-explosive depth charges as warning shots. The submarine had been hiding deep underwater for days. It was out of radio contact, so the crew did not know whether war had already broken out. Conditions on board were extremely bad. It was built for the Arctic and its ventilator had broken in the tropical water. The heat inside was unbearable, ranging from 113°F near the torpedo tubes to 140°F in the engine room. Carbon dioxide had built up to dangerous concentrations, and crew members had begun to fall unconscious. Depth charges were exploding right next to the hull. One of the crew later recalled: “It felt like you were sitting in a metal barrel, which somebody is constantly blasting with a sledgehammer.”

Increasingly desperate, Captain Savitsky ordered his crew to prepare their secret weapon:

Maybe the war has already started up there, while we are doing somersaults here. We’re going to blast them now! We will die, but we will sink them all—we will not disgrace our Navy!1

Firing the nuclear weapon required the agreement of the submarine’s political officer, who held the other half of the firing key. Despite the lack of authorization by Moscow, the political officer gave his consent.

On any of the other three submarines, this would have sufficed to launch their nuclear weapon. But by the purest luck, submarine B-59 carried the commander of the entire flotilla, Captain Vasili Arkhipov, and so required his additional consent. Arkhipov refused to grant it. Instead, he talked Captain Savitsky down from his rage and convinced him to give up: to surface amidst the US warships and await further orders from Moscow.2

We do not know precisely what would have happened if Arkhipov had granted his consent—or had he simply been stationed on any of the other three submarines. Perhaps Savitsky would not have followed through on his command. What is clear is that we came precariously close to a nuclear strike on the blockading fleet—a strike which would most likely have resulted in nuclear retaliation, then escalation to a full-scale nuclear war (the only kind the US had plans for). Years later, Robert McNamara, Secretary of Defense during the crisis, came to the same conclusion:

No one should believe that had U.S. troops been attacked by nuclear warheads, the U.S. would have refrained from responding with nuclear warheads. Where would it have ended? In utter disaster.3

Ever since the advent of nuclear weapons, humans have been making choices with such stakes. Ours is a world of flawed decision-makers, working with strikingly incomplete information, directing technologies which threaten the entire future of the species. We were lucky, that Saturday in 1962, and have so far avoided catastrophe. But our destructive capabilities continue to grow, and we cannot rely on luck forever.

We need to take decisive steps to end this period of escalating risk and safeguard our future. Fortunately, it is in our power to do so. The greatest risks are caused by human action, and they can be addressed by human action. Whether humanity survives this era is thus a choice humanity will make. But it is not an easy one. It all depends on how quickly we can come to understand and accept the fresh responsibilities that come with our unprecedented power.

This is a book about existential risks—risks that threaten the destruction of humanity’s longterm potential. Extinction is the most obvious way humanity’s entire potential could be destroyed, but there are others. If civilization across the globe were to suffer a truly unrecoverable collapse, that too would destroy our longterm potential. And we shall see that there are dystopian possibilities as well: ways we might get locked into a failed world with no way back.

While this set of risks is diverse, it is also exclusive. So I will have to set aside many important risks that fall short of this bar: our topic is not new dark ages for humanity or the natural world (terrible though they would be), but the permanent destruction of humanity’s potential.

Existential risks present new kinds of challenges. They require us to coordinate globally and intergenerationally, in ways that go beyond what we have achieved so far. And they require foresight rather than trial and error. Since they allow no second chances, we need to build institutions to ensure that across our entire future we never once fall victim to such a catastrophe.

To do justice to this topic, we will have to cover a great deal of ground. Understanding the risks requires delving into physics, biology, earth science and computer science; situating this in the larger story of humanity requires history and anthropology; discerning just how much is at stake requires moral philosophy and economics; and finding solutions requires international relations and political science. Doing this properly requires deep engagement with each of these disciplines, not just cherry-picking expert quotes or studies that support one’s preconceptions. This would be an impossible task for any individual, so I am extremely grateful for the extensive advice and scrutiny of dozens of the world’s leading researchers from across these fields.4

This book is ambitious in its aims. Through careful analysis of the potential of humanity and the risks we face, it makes the case that we live during the most important era of human history. Major risks to our entire future are a new problem, and our thinking has not caught up. So The Precipice presents a new ethical perspective: a major reorientation in the way we see the world, and our role in it. In doing so, the book aspires to start closing the gap between our wisdom and power, allowing humanity a clear view of what is at stake, so that we will make the choices necessary to safeguard our future.

I have not always been focused on protecting our longterm future, coming to the topic only reluctantly. I am a philosopher, at Oxford University, specializing in ethics. My earlier work was rooted in the more tangible concerns of global health and global poverty—in how we could best help the worst off. When coming to grips with these issues I felt the need to take my work in ethics beyond the ivory tower. I began advising the World Health Organization, World Bank and UK government on the ethics of global health. And finding that my own money could do hundreds of times as much good for those in poverty as it could do for me, I made a lifelong pledge to donate at least a tenth of all I earn to help them.5 I founded a society, Giving What We Can, for those who wanted to join me, and was heartened to see thousands of people come together to pledge more than £1 billion over our lifetimes to the most effective charities we know of, working on the most important causes. Together, we’ve already been able to transform the lives of tens of thousands of people.6 And because there are many other ways beyond our donations in which we can help fashion a better world, I helped start a wider movement, known as effective altruism, in which people aspire to use evidence and reason to do as much good as possible.

Since there is so much work to be done to fix the needless suffering in our present, I was slow to turn to the future. It was so much less visceral; so much more abstract. Could it really be as urgent a problem as suffering now? As I reflected on the evidence and ideas that would culminate in this book, I came to realize that the risks to humanity’s future are just as real and just as urgent—yet even more neglected. And that the people of the future may be even more powerless to protect themselves from the risks we impose than the dispossessed of our own time.

Addressing these risks has now become the central focus of my work: both researching the challenges we face, and advising groups such as the UK Prime Minister’s Office, the World Economic Forum and DeepMind on how they can best address these challenges. Over time, I’ve seen a growing recognition of these risks, and of the need for concerted action.

To allow this book to reach a diverse readership, I’ve been ruthless in stripping out the jargon, needless technical detail and defensive qualifications typical of academic writing (my own included). Readers hungry for further technical detail or qualifications can delve into the many endnotes and appendices, written with them in mind.7

I have tried especially hard to examine the evidence and arguments carefully and even-handedly, making sure to present the key points even if they cut against my narrative. For it is of the utmost importance to get to the truth of these matters—humanity’s attention is scarce and precious, and must not be wasted on flawed narratives or ideas.8

Each chapter of The Precipice illuminates the central questions from a different angle. Part One (The Stakes) starts with a bird’s-eye view of our unique moment in history, then examines why it warrants such urgent moral concern. Part Two (The Risks) delves into the science of the risks facing humanity, both from nature and from ourselves, showing that while some have been overstated, there is real risk and it is growing. So Part Three (The Path Forward) develops tools for understanding how these risks compare and combine,combine, and new strategies for addressing them. I close with a vision of our future: of what we could achieve were we to succeed.

This book is not just a familiar story of the perils of climate change or nuclear war. These risks that first awoke us to the possibilities of destroying ourselves are just the beginning. There are emerging risks, such as those arising from biotechnology and advanced artificial intelligence, that may pose much greater risk to humanity in the coming century.

Finally, this is not a pessimistic book. It does not present an inevitable arc of history culminating in our destruction. It is not a morality tale about our technological hubris and resulting fall. Far from it. The central claim is that there are real risks to our future, but that our choices can still make all the difference. I believe we are up to the task: that through our choices we can pull back from the precipice and, in time, create a future of astonishing value—with a richness of which we can barely dream, made possible by innovations we are yet to conceive. Indeed, my deep optimism about humanity’s future is core to my motivation in writing this book. Our potential is vast. We have so much to protect.

  1. Blanton, Burr & Savranskaya (2012).↩︎

  2. Ellsberg (2017), pp. 215–17.↩︎

  3. McNamara (1992).↩︎

  4. Any errors are, of course, my own. You can find an up-to-date list of any known errors at I am grateful for expert advice from Fred Adams, Richard Alley, Tatsuya Amano, Seth Baum, Niel Bowerman, Miles Brundage, Catalina Cangea, Paulo Ceppi, Clark Chapman, David Christian, Allan Dafoe, Richard Danzig, Ben Day, David Denkenberger, Daniel Dewey, Eric Drexler, Daniel Ellsberg, Owain Evans, Sebastian Farquhar, Vlad Firoiu, Ben Garfinkel, Tim Genewein, Goodwin Gibbons, Thore Graepel, Joanna Haigh, Alan Harris, Hiski Haukkala, Ira Helfand, Howard Herzog, Michael Janner, Ria Kalluri, Jim Kasting, Jan Leike, Robert Lempert, Andrew Levan, Gregory Lewis, Marc Lipsitch, Rosaly Lopes, Stephen Luby, Enxhell Luzhnica, David Manheim, Jochem Marotzke, Jason Matheny, Piers Millet, Michael Montague, David Morrison, Cassidy Nelson, Clive Oppenheimer, Raymond Pierrehumbert, Max Popp, David Pyle, Michael Rampino, Georgia Ray, Catherine Rhodes, Richard Rhodes, Carl Robichaud, Tyler Robinson, Alan Robock, Luisa Rodriguez, Max Roser, Jonathan Rougier, Andrew Rushby, Stuart Russell, Scott Sagan, Anders Sandberg, Hauke Schmidt, Rohin Shah, Steve Sherwood, Lewis Smith, Jacob Steinhardt, Sheldon Stern, Brian Thomas, Brian Toon, Phil Torres, Martin Weitzman, Brian Wilcox, Alex Wong, Lily Xia and Donald Yeomans.↩︎

  5. I also made a further pledge to keep just £18,000 a year for myself and to donate anything in excess. This baseline adjusts with inflation (it is currently £21,868), and doesn’t include spending on my child (a few thousand pounds each year). So far I’ve been able to give more than a quarter of everything I’ve ever earned.↩︎

  6. At the time of writing, Giving What We Can members have donated £100 million to effective charities (Giving What We Can, 2019). This is spread across many different charities, so it is impossible to give a simple accounting of the impact. But even just looking at the £6 million in donations to provide malaria nets, this provided more than 3 million person-years of protection, saving more than 2,000 lives (GiveWell, 2019).↩︎

  7. There is effectively another book-worth of content tucked away in the notes for readers who are eager to know more. If that’s you, I’d suggest using a second bookmark to allow you to flip back and forth at will. I’ve endeavored to keep the average quality of the notes high to make them worth your time (they are rarely just a bare citation). I’ve tried to be disciplined in keeping the main text on a straight path to its destination, so the scenic detours are all hidden in the notes. You may also be interested in the appendices, the list of further reading (p. 285), or the book’s website,, for even more information and discussion.↩︎

  8. Of course even after extensive fact-checking, it would be naïve to think no bias or error has slipped through, so I hope readers will help catch and correct such weaknesses as remain.↩︎