Revisiting organic agriculture and the global food supply, twenty years on

We review here the findings from an empirical study of yield ratios between plant and animal foods grown organically compared to either conventional or low-input peasant farming methods. Our 2007 study demonstrated that organic yields were sufficiently large, in principle, to provide much of the global food supply in terms of calories across all major food groups. Publication of the study encountered strong opposition from reviewers as well as support. Once published, the findings were widely cited and well received by practitioners of sustainable agriculture and agroecologists. Several follow-up studies using larger datasets and newer analytical methods found yield ratios (yield gaps) similar to or somewhat larger than ours. Most of these studies also concluded that organic production methods could make a major contribution to the global food supply. In a food-system context, organic production could also contribute to carbon sequestration and maintenance of native biodiversity, particularly if less land were devoted to growing livestock feed or crops for biofuels, and if less food were wasted. Organic agriculture is often more profitable for farmers, boosts rural employment, and improves social connections among farmers and between farmers and consumers. Together, these elements contribute to the kind of food system that simultaneously serves people and nature.