There has been intense speculation for a number of years that world phosphate reserves are dwindling in amount and quality. Assuming current rates of use, world phosphate rock reserves and resources should be available for the foreseeable future. Previous estimates of global phosphate rock resources ranged from 91 billion metric tons to over one trillion metric tons. Since then, there is limited detailed information on world phosphate rock reserves and resources available in conventional scientific literature. The IFDC estimate of global phosphate rock reserves is approximately 60,000 mmt of concentrate, while the IFDC estimate of global resources is approximately 290,000 mmt.