Over the past 50-60 years, unbridled growth in global fertilizer use to boost and maintain crop yields has polluted natural and agricultural systems, leading to a range of harmful outcomes. The abundant and inefficient application of fertilizer is a leading cause of water pollution, as well as a contributor to greenhouse gases and the deterioration of air and soil quality. This, in turn, has adverse consequences for public health, the climate, wildlife, and business-including tourism, agribusiness, commercial fishing, and farming. Although its use, in combination with other Green Revolution technologies, is credited for feeding the world and averting a more dramatic expansion of agriculture into natural landscapes, today's fertilizer use is considered to be pushing the planet's biogeochemical boundaries.