The Big Ratchet: How Humanity Thrives in the Face of Natural Crisis

Columbia professor and MacArthur fellow DeFries (Ecosystems and Land Use Change) follows the trajectory of the human species by tracing how we meet our most basic need—feeding ourselves. DeFries frames humanity’s relationship to the environment in three-step cycles of pivots, new innovations that allow us to stave off hunger by extracting energy from nature more efficiently; ratchets, the population increase that this new bounty allows; and hatchets, obstacles that arise when the innovation has reached a limit that lead to the invention of new pivots. Her history of agriculture tracks our path from hunter-gatherers to farmers to city dwellers: in each successive stage we have grown more reliant on the efforts of fewer people to feed more, and have utilized sources of energy which steal fewer of the calories by moving from human power, to animal power, to the power of fossil fuels. Neither technophile nor doomsayer, DeFries sees today’s hatchet not in overpopulation but in the uneven distribution of access to new methods and in the declining quality of the human diet. DeFries places her faith in human creativity as a primary means to our survival, an appealing point of view for the hopeful but concerned reader. B&w images. (Sept.)