Martin Rowe

When the scattered human communities of the twenty-second century tell their various stories about just how badly we screwed up the planet in the previous century, alongside the emergence of factory farming, deforestation, biodiversity loss, and our failure to move on from our addiction to “cheap” energy from fossil fuels, they might reflect on the use and abuse of one mineral: phosphorus.

Phosphorus, as the Pennsylvania Nutrient Management Program dryly puts it, “is an essential element for plant and animal growth,” and mainly used in fertilizers. The site goes on to state that once the element runs off the land into the waterways it (along with the nitrogen in the fertilizer) is responsible for eutrophication, which, observes the site with admirable sangfroid, causes “increased growth of undesirable algae and aquatic weeds, as well as oxygen shortages resulting from their die-off and decomposition,” restricting “water use for fisheries, recreation, industry, and drinking.” These are the “dead zones” where no aquatic life exists and bacterial infestations make water poisonous for everyone.

The website goes on to describe how best to apply phosphorus to avoid run-off and eutrophication. However, noticeably absent from this site geared to farmers is the  fact that phosphorus is a finite resource, of which ninety percent is only available in five countries: Morocco, China, South Africa, Jordan, and the United States. The U.S. imports most of its phosphorus, since it has only 25 years’ supply left. As Renee Cho of the Earth Institute of Columbia University notes,  “Morocco . . . controls up to 85 percent of the remaining phosphate rock reserves. However, many of Morocco’s mines are located in Western Sahara, which Morocco has occupied against international law. Despite the prevalence of phosphorus on earth, only a small percentage of it can be mined because of physical, economic, energy or legal constraints.” She continues:

With a world population that is projected to reach 9 billion by 2050 and require 70 percent more food than we produce today, and a growing global middle class that is consuming more meat and dairy, phosphorus is crucial to global food security. Yet, there are no international organizations or regulations that manage global phosphorus resources. Since global demand for phosphorus rises about 3 percent each year (and may increase as the global middle class grows and consumes more meat), our ability to feed humanity will depend upon how we manage our phosphorus resources.

Unfortunately, most phosphorus is wasted. Only 20 percent of the phosphorus in phosphate rock reaches the food consumed globally. Thirty to 40 percent is lost during mining and processing; 50 percent is wasted in the food chain between farm and fork; and only half of all manure is recycled back into farmland around the world.

Let’s be clear here. Phosphorus is non-negotiable necessity. We need it in our bodies, we need it in our soils, and we need it to grow all the things we eat. Yet, not only are we using up the precious available resources rapidly, but we are wasting a lot of it in run-off and on growing vast acreages of crops to feed to animals—a process that is itself a deeply inefficient and wasteful use of land, water, fertilizer, and fossil fuel energy.

Now, it may be the case that in thirty years time humankind will have found a way not to need so much phosphorus to grow its food. Certainly, as Ruth DeFries argues in The Big Ratchet: How Humanity Thrives in the Face of Natural Crisis, the harnessing of phosphorus and nitrogen in the use of fertilizer radically altered how food was grown and how much of it could be grown. It ensured that the Malthusian fear of vast, starving populations has yet to be realized. That “pivot” (as DeFries calls the technological shift) in the face of the need to feed a population of 9, 11, or even 13 billion might occur again.

But that’s a very, very big gamble. In the meantime, surely, rather than rely on magical thinking about human ingenuity rescuing us from our own short-sightedness, we should apply a precautionary principle and move away as quickly as possible from using artificial fertilizers to grow massive monocultures of crops to feed to ever-increasing numbers of animals whom we eat. And even if we can’t have that conversation among policy makers at the moment, at the very least it would help if extension services, governments, and agencies concerned with food security faced up to the reality that phosphorus is only theoretically abundant and acted accordingly.