Alan Weisman is the author of several books, including The World Without Us: an international best-seller translated in 34 languages, a finalist for the National Book Critics Circle Award, and winner of the Wenjin Book Prize of the National Library of China.
Countdown: Our Last, Best Hope for a Future on Earth? addresses a question I’d left dangling at the end of my last book, The World Without Us, a thought experiment that imagined what would happen if people vanished from our planet. The idea of theoretically wiping us from the Earth was to show that, despite colossal damage we’ve wreaked, nature has remarkable healing powers. When relieved of the pressures we humans daily heap upon it, restoration and renewal commence with surprising swiftness. My hope was that readers, seduced by the gorgeous prospect of a refreshed, healthy Earth, might ask themselves how we could add Homo sapiens back into the picture—only in harmony, not mortal combat, with the rest of nature.
The question I’d left them to ponder was how many people can this planet really hold without capsizing it? A million more of us every 4½ days didn’t sound sustainable– was it time for us to consider gradually bringing ourselves down to a workable equilibrium with our Earthly habitat, before nature brutally did that for us?
This delicate, potentially explosive notion generated so much subsequent discussion that I realized I should investigate it fully. It’s easy to grasp why populations of prey, predators, and forage plants have to be kept in balance in a national park, but much harder when your own species is in question. Anticipating the cultural and emotional pitfalls, I’d need to apply objective tools of journalism to learn if the optimum number of humans could actually be determined, and if there were something we could realistically and humanely do about it.
I also had to confront three corollary questions: How much ecosystem is required to preserve human life – what species or ecological processes are essential to our survival? And if, in order to survive, we have to avoid growing beyond 10 billion—or even reduce our numbers from our current 7+ billion—is there an acceptable, nonviolent way to convince a majority of the world’s religions, nationalities, and political systems that it's in their best interest to do so, or is there anything in their liturgies, histories, or belief systems that might embrace the seemingly unnatural idea of limiting ourselves? Finally, how might we design an economy for a shrinking population, and then for a stable, optimal one—meaning, a way to prosper without constant growth?
My research ended up taking me to 21 countries, starting in Israel and Palestine, ending in Iran, with much of Europe, Africa, the Americas, and the Far East in between. More than one expert I met commented that I was asking the most important questions on Earth—but they were probably impossible to answer.
My reply was that if these are the most important questions on Earth, we’d damn well better try.