Phosphorus is an element that few care about but everyone needs. It is one of the major components of the fertilizers that we use to increase crop yields. The good news is that it can be produced naturally. Bird poop and dead animals have supplied it, but they don’t exist in sufficient quantities to feed the world. Hence, mining. The bad news is that, at present consumption levels and with current agricultural processes, we may only have a 35 year supply. There are replacement technologies being developed; but increasing the efficiency of what we use may be necessary. Currently, about 80% of the phosphorus applied is wasted. Of the phosphorus that we ingest, most of it passes through us, which can be a good thing if it can be harvested. Until then, phosphorus adds itself to the list of essential elements and materials that aren’t available in supplies that can be considered sustainable.