This article in Foreign Policy on "Peak Phosphorus" (just like "Peak Oil" only with phosphorus) is at once enlightening yet also over the top. In the enlightening phase, it raised my awareness of the availability of this element and how geographically limited the mining activity is. And also what the level of reserves is estimated to be.
But then the authors goes right on the cliff of irrationality with these comments:
"If we fail to meet this challenge, humanity faces a Malthusian trap of widespread famine on a scale that we have not yet experienced."
This was so shocking as just in the previous paragraph, they had clearly stated that
"... unlike fossil fuels, phosphorus can be used over and over -- this is what occurs in natural ecosystems, where it is recycled innumerable times from its first mobilization from the Earth's crust to its eventual deposition into lake and ocean sediments."
Why they felt an urge to sway to the grand exaggeration and fearmongering is beyond me.