While it might not surprise us to read that mosquitoes have a niche that affects their distribution on the planet, it might be more difficult to recognize that we humans do as well. We are animals after all, and can be studied as such by ecologists. Even with the spread of air-conditioning, and all the creature comforts afforded by burning fossil fuels by the gigaton, we still mostly inhabit the same shockingly narrow band of the globe that we have for millenniums. But as we push the climate beyond the norms of the past three million years we will hit the hard limits of physiology. And as the familiar rhythms of the seasons grow more syncopated and strange, some swath of our range will be increasingly foreclosed, to God knows what geopolitical effect. Many of us will have to move.
Along this unsettling journey into the future, the mood is leavened here and there by oddities, which Dunn dusts off like the docent of a strange natural history museum. We learn that the Taung child, one of the earliest hominins known to science, was eaten by eagles. We learn that the yeasts that make beer come from the bodies of wasps. That when humans spread out into new landmasses our “face mites diverged.” The impression all this arcana leaves with the reader is that we live in a much weirder, more disorienting world than we tend to appreciate.
We simplify this chaos, this riot of life, at our peril. We hoist plants from their natural context, consign them to vast monocultures, then act surprised when the rest of nature conspires to tear them down. We panic when bees fail to submit to the rote demands of industrial agriculture. But if simplifying nature is the cause of so many modern ills, then Dunn’s policy prescription, conversely, comes down to one simple dictum: Diversify. Diversify the microbes in your intestines, the crops in your fields, the plants in your watershed, the research in your grant proposals. Recruit the forests to filter your water. Let a trillion microbial flowers bloom.
This strategy works because nature is cleverer than us. The science historian George Dyson once described evolution itself as a kind of computational process that solves problems like how to swim, and how to fly. But the new problems we’ve given it to solve are ill considered, and the solutions it produces often undesirable. We dare life to overtop the levees of pesticides, herbicides, antibiotics; to overrun the concrete outcrops of cities, insinuate itself in the cracks of human society and pick the locks of our immune system. If we wipe out charismatic megafauna, of the sort that graces the brochures of conservation nonprofits, fine, nature seems to say, a florescence of rats and crows it is. Want to live in modular outcrops of steel, glass and cement, fed by rivers of pavement spanning thousands of miles? Very well, this will be a migration corridor for mice, pigeons and disease. They represent life too, after all, and the planet gives not a whit if it’s inhabited by lions or cockroaches. There are now beetles that consume only grains, mosquitoes that live only in the London metro. “Evolution creates,” Dunn writes, “and acts of creation are never complete.”
Dunn’s account leaves an overwhelming impression of fecundity, growth, adaptation. But this isn’t a naïvely rosy vision of the future like some contrarian tracts on the resilience of nature in the Anthropocene. From a human perspective this will be an impoverished world, and many of Dunn’s warnings are concrete and sobering. But readers are left to draw many of the connections for themselves — and as the anecdotes and factoids pile up, they begin to take on a koan-like quality. What does it mean that you can’t make sourdough bread in tightly sealed homes? That parasites stowed away onto the International Space Station? That baseball pitchers bean more batters in retaliation when it gets hotter? That drivers honk more? No one knows, Dunn seems to say. But we’ll soon find out. The rivers are rising.