The Dust Bowl

The Great Plains were originally prairie — grass with roots metres deep — and had been ploughed into wheat fields within a single generation. The disaster was man-made in a precise sense: the prairie was held together by deep grass roots, and those had been ploughed out within a generation during an unusually wet spell. When the drought returned — as it always does — there was nothing left to hold the soil. The response was the Soil Conservation Service and a lasting reorientation of American agricultural policy, and the episode has become a fixed reference in debates about farming and climate.