L. David Roper
2 July, 2016
Potash is indispensible in creating fertilizer for modern farming. It is also used in modern batteries. The graph below shows the phosphate-rock extraction data for the world and a Verhulst functions fit to the data in order to extrapolate into the future.
Phosphate-rock extraction rate for the world and a Verhulst functions fit to the data.
The red curve is a fit with total amount to be extracted of ~11x109 tonnes, which incorporates the latest reserves estimate (~9.5x109 tonnes).
Dividing the extraction curve above by the projected world population (asymptote ~1010), one gets: