"In “The Decline and Fall of the Human Empire,” Henry Gee, a senior editor at Nature, argues that we as a species have already optimized far too much and become so homogenous in our genetic makeups as to put ourselves on the brink of extinction.
In his dire prophecy, at once chatty and ambitious, Gee moves across hundreds of thousands of years of genetic evidence to explain the rise and fall of Homo sapiens. Earth once boasted at least nine human species, but when only one remained to spread across, change and dominate the natural environment, humanity lost a lot of genetic diversity. “There is more genetic variation in a troupe of chimpanzees in Africa,” Gee writes, “than in the entire human species.” We also overexploited the Earth’s natural resources, narrowing the genomes of the things we eat. We now rely on a smaller number of crops than ever before, leaving our food supply ever more susceptible to disease, the vagaries of weather and geopolitical conflict.
In our increasingly small and interconnected world, financial shock and disease both travel faster: Viruses and bacteria, unimpeded by quirky pockets of biological difference, will hit everything at once. That’s why optimizing for educational attainment or the perfect ear of corn could spell our end, even if we manage to avoid the fallout from global warming or nuclear war. We need genetic “sparring partners,” Gee insists, if we hope to survive.
Gee thinks the best way forward is to seek another world, beyond Earth, where new human species could develop. Start with the moon. Or maybe the inside of an asteroid, after it’s been mined of its wealth of mineral resources. Gee posits that the hollow husk of one largish asteroid could absorb at least the population of Canada — talk about a 51st state!
We must move fast, he argues: Extinction may be 10,000 years off, but we only have about two centuries to design these new space colonies, because as the population declines, so will our capacity for technological innovation.
Gee mentions the colonization of space so casually in his prologue that you might take it for another April Fools’ joke. When he returns to it near the end of his book, he leaves the details somewhat loose. He envisions artificial photosynthesis to fuel new sources of food, and a system of solar panels, optical fibers and mirrors to deliver sunlight: “There is no reason it shouldn’t be as bright as day.”
He raises but does not answer political questions, too: Might countries go to war over disputed mineral-rich territories in space? Might tech trillionaires decide to fund private colonies there? Of course, you think. Can we dismiss anything as a joke anymore?” [1]
THE DECLINE AND FALL OF THE HUMAN EMPIRE: Why Our Species Is on the Edge of Extinction | By Henry Gee | St. Martin’s Press | 278 pp. | $29
1. What if We Select Ourselves Out of Existence?: Nonfiction. Zernike, Kate. New York Times (Online) New York Times Company. Mar 23, 2025.