Henry Gee: The Decline and Fall of the Human Empire - Why Our Species is on the Edge of Extinction review – survival instincts

Henry Gee’s previous book, A Brief History of Life on Earth, made an interestingly downbeat read for a title that won the UK’s science book prize. He emphasised that a constant feature of that history is extinction. Disappearing is simply what species do. A few endure for an exceptionally long time (hello, horseshoe crabs), but all suffer the same fate in the end.

Some at least go down as ancestors of succeeding species. Many more just vanish. Evolution permits gradual development of more complex forms. That’s how we got here. But the way it works – by reproduction with variation, then selection – means it is inescapably an enormous death machine. Humans can enjoy the view from our intelligent perch because we sit on top of an enormous mountain of corpses.

Will the death machine come for us, then? And is there any escape for an intelligent biped that is conscious of the possibility? Yes, and possibly, says Gee in his follow up effort.

The news on the first question is bad, he reports. After rehearsing the emergence of a single, dominant hominid species, Homo sapiens, which now holds sway over the entire planet, he argues that our demise is imminent, geologically speaking. That’s not because of pandemics, climate change, nuclear war or robopocalypse, though they don’t exactly improve our chances. It looks that way because our long-established habit of increasing our population has rather suddenly been broken. The “demographic transition” that development theorists used to discuss in the 1960s turned out to be more drastic than they imagined.   Birth rates did not just ease off to roughly replacement level but, in many countries, fell well below it. That phenomenon, apparently unstoppable, is so widespread that global population is now predicted to peak around the middle of this century, then decline rather steeply. If current trends persist, the global total might fall to a few billion by the end of the next century. By 2300 it could be less than a billion.

And that, he insists, is a sign of impending extinction. It would lead to isolated pockets of humans, already genetically much more homogenous than other species, each vulnerable to disaster and, eventually, all fading out. The planet without humans often depicted in fiction would become a reality in, perhaps, a few thousand years.

After that bracing exposition, Gee does offer a get-out. A species can improve its chances of survival by expanding its ecological niche, he explains. Humans have used technology to do this, which is why we can now live anywhere on Earth. The next step, the ultimate niche expansion, would be to learn how to live in space.

Gee rehearses a few ways we might begin to do that – on space stations, colonies on the Moon or Mars, or perhaps establishing cities inside hollowed out asteroids. Readers of science fiction, or devotees of Elon Musk, will know the rest.

He is realistic about the pros and cons of trying to survive off-planet. The pioneers, if such there be, will probably need to be a little nuts. But plenty of past colonisers fit that description, so he reckons there will be enough takers for the voyage out to maintain the necessary impetus.

One can see the need to contrive such an ending for the book. Is it convincing? I’m not sure. Gee is more authoritative when writing about the history of life, the subject of his earlier books, than in his new guise as a futurologist. That’s unsurprising. As he acknowledges, futurology does not lend itself to being authoritative, however hard folk like Yuval Harari try. However, having argued for human exceptionalism, he takes relatively little notice of the fact that the species he now puts on the danger list is the first one ever seen (as far as we know) that knows what usually happens to species.

That, surely, affects the mechanics of extinction drastically. Even without going into details, it seems plausible that a species that has a conscious awareness of looming extinction is better placed than any that has existed before to avoid it. In that light, it feels odd to offer space travel as the only way of continuing this story. There are a wealth of other technological possibilities that could open up quite different futures, palatable or otherwise, in the next few hundred years.

And we might look beyond that horizon. Gee insists that the matter is urgent, because otherwise steep population decline in the next century or two will snuff out further invention. A global civilisation of hundreds of millions is a prerequisite, he maintains, for the kind of technical advances we need to secure a future in space.

Well, true, more people means more ideas, and more people concentrated in cities means more cross-fertilisation of those ideas. But a global population of less than a billion, far less interconnected than ours, still somehow gave rise to Galileo, Newton and Darwin. There’s little reason to accept that the twilight of innovation must come as swiftly as Gee asserts. Meanwhile, although pursuing a spaceward trajectory as a path to avoid extinction remains a gripping notion, there are other more pressing problems for the eight or nine billion of us who will populate the rest of the twenty-first century to focus on.

• The Decline and Fall of the Human Empire: Why Our Species is on the Edge of Extinction by Henry Gee (Picador, £18.99)
• More book reviews on theartsdesk