The document provides information about world phosphate rock reserves and resources:
1) It reviews past literature and estimates of global phosphate rock reserves and resources that range from 15,000 million metric tons to over 1,000,000 million metric tons.
2) It estimates current world phosphate rock reserves at approximately 60,000 million metric tons of concentrate and resources at around 290,000 million metric tons, totaling around 460,000 million metric tons when including potential resources.
3) It concludes based on this data that concerns about "peak phosphorus" occurring in the next 20-25 years are unfounded, and that reserves will last for 300-400 years at current production rates.