A half-century of global phosphorus flows, stocks, production, consumption, recycling, and environmental impacts

Abstract

Many contemporary aspects of the global phosphorus cycle have been evaluated over the last several years, but a comprehensive picture over time has not yet been provided. In this work, we generate a detailed quantitative picture of dynamic phosphorus stocks and flows, for both human and animal uses, from 1961 to 2013. During that half-century, total phosphorus consumption has increased fivefold, to 31 million metric tons (31Tg). However, losses and diversions from extraction to final consumption result in only about 22% of the extracted phosphorus being actually consumed as human food. Agricultural practices have changed as well, with on-farm wastes yielding to manufactured fertilizers as the primary source of phosphorus. Non-food uses such as detergents and metal coatings were about five times larger in 2013 than in 1961, though they currently account for only about a quarter of all phosphorus use. Waste phosphorus flows to water, dominated by agricultural operations in 1961, have now been overtaken by loss from phosphate rock mining. Overall, the phosphorus cycle shows a history of inefficiency and loss, but also many opportunities for improvements that could lead to a much more sustainable situation going forward.