Modern agriculture is dependent on phosphorus derived from phosphate rock for the fertilization of agricultural fields. Phosphorus is a non-renewable resource and current global reserves may be depleted in 50–100 years. It is widely acknowledged within the fertilizer industry that the quality of remaining phosphate rock is decreasing and production costs are increasing. Yet future access to phosphorus receives little or no international attention. This paper puts forward the case for including long-term phosphorus scarcity on the priority agenda for global food security. Opportunities for recovering phosphorus and reducing demand are also addressed together with institutional challenges.