The ecologist Ruth DeFries calls the last half-century of agricultural industrialization “the Big Ratchet.” It is the latest and most extreme example of a cycle of technological innovation that has allowed humanity to thrive in the face of constant ecological crises. For thousands of years people have been coming up with new ways to wring more food from nature, then running up against some ecological barrier—often a side effect of the original innovation—and engineering a way around it.
Humans invented agriculture, which depleted the soil, which they replenished with animal and human manure, which allowed towns to grow, which caused septic disease, so sewers were invented, which diverted night soil from the fields, so fertilizer was invented, which made monocultures possible, which allowed pests to run rampant, so insecticides were invented; and so it went, accelerating exponentially as the population grew from a billion-and-a-half people to seven billion in the last century, more and more of them living in cities, where they’re fed by fewer people harnessing technology to manage ever larger crops.
DeFries calls each innovation a ratchet, and the inevitable obstacle a hatchet. Technology ratchets up the population. Then the hatchet falls, and a new ratchet must be invented.