Today I stumbled on this article on the site of Forbes. The authors rants against what he calls “foolish” systems to recycle phosphorus, because there is no shortage of this mineral resource.
But first, why should we actually care about phosphorus? Well, because it essential for live as we know it. For instance our DNA contains this chemical, and it plays an essential role in the energy system of our cells.
All organisms on this planet need phosphorus, plants, animals and us. We, of course, get our needed amounts through our food. Because of this, phosphorus is an essential component of fertilizer used to feed to the world.
In the world of today much phosphorus used by humans is mined, and subsequently fed to plants, and ultimately after being used by us it ends up in the ocean. However, phosphorus is a resource with a finite supply. The question is, of course, how much of this stuff is there on this planet?
According to the article I cited above, there are 67 million tonnes of mineral reserves or 300 years of supply as calculated by the author of that article. But as he remarks this only refers to mineral reserves, i.e. the amounts we could easily mine, while the total amount of phosphorus equals to 1,500 years of supply.
No surprise that he argues that scientists should not waste their time and efforts to seek systems to recycle phosphorus, as there are many much more urgent problems in the world.
Though he has a point, I think his argument is a bit shortsighted. First, his estimates are based on the current annual production of phosphorus. However, with an increasing population also more phosphorus will be needed, and hence more mining will be required and hence reserves will deplete faster.
Secondly, the author ignores the environmental aspects of phosphorus mining. It is a well-known fact that mining has a negative effect on the environment. And with dwindling reserves, lower grade ores will be mined, which will increase these impacts even further.
Additionally, though phosphorus recycling is not an urgent issue on Earth, but it might be essential for our efforts to colonize our Solar System, in particular on lengthy but temporal missions. But to be honest phosphorus needs in space could be met by space mining, though that would be most attractive for more permanent space settlement than to, say, a manned round-trip to Mars.