Phosphorus is the 15th element on the periodic table and is present in every strand of DNA and provides the energy to allow us to move.
It is best known for glowing in the dark which is also how it got its name (from Greek, meaning "bringer of light".)
Had we known how crucial it was to all living things we may have called it the bringer of life.
Living things either obtain it from the soil like plants or by eating plants or eating animals that eat plants.
When the amount removed from the soil is balanced by the decay of dead plants and animals (and animal waste), it can remain in the food chain indefinitely. However, modern farming techniques remove more than is replaced and so we need to fertilise crops to produce enough to feed everyone.
Initially, we obtained the additional fertiliser in the form of bird droppings which over centuries had formed thick enough layers on island bird colonies so that it was mined. In less than a century though they had been exhausted, resulting in a significant reduction in the bird population and concern for our future. Luckily a process to obtain high-grade fertiliser was devised from phosphate rock which was itself ancient deposits of marine life that settled in shallow seas.
For the last century, it has been the principal source for the fertiliser industry.
How much is there?
It is not scarce, but it is finite, and expectations are that we should have enough to last as much as 400 years to perhaps as little as 50 years.
Global demand is expected to be about 255 million tons in the coming year.
The issue is only partly the volume; it is also the location and concentration that is cause for concern.
As much as 70% of the known deposits of phosphate rock is concentrated in a small part of the Sahara desert in a region that is controlled by Morocco but claimed by the Sahrawi who are seeking independence.
World demand is mostly met by the many other regions like China and the US which produce as much or more than Morocco, but don’t have the reserves.
If our dependence on phosphate rock and the rate of consumption continue, we may find that whoever controls the remaining reserves can control a significant monopoly on fertiliser.
As the world population continues to grow (albeit slower) and get more wealthy (favouring a more meat reliant diet) we will need to increase the area used for agriculture and increase the volume of fertiliser to produce it.
When a powerful king controls so much of the reserve, it may be used to manipulate the market price or the area could become more politically unstable, which may have a far-reaching impact not only on the world economy but the entire population.
South Africa has remained committed to assisting in resolving the land dispute and even attempted to block Morocco's readmission to the African Union last year because of it.
The price of phosphate rock is currently about $100 per tonne, but before 2007, it had not risen above $50 in the two decades before that. In 2008 it hit $430 (thankfully not for very long), but it came on the back of rising oil prices, another finite commodity that we may not be weaning ourselves off fast enough.
Should another oil spike occur amid increased tension in the Middle East or threats of conflict elsewhere a similar spike in fertiliser may reoccur. Should that also coincide with a natural climate-related disaster like floods or drought and food price increases could see both popular revolts as a result and severe food shortages for the most vulnerable.
The reserves alone are not enough for us to consider this business as usual.
What should we do
We need to revisit how much fertiliser we use, what the bulk of diets consist off and continue to work on ways to recover more phosphorus from animal waste and our own.
Which brings us back to its name and its discovery.
Alchemists believed a philosopher's stone would allow base metals to be turned to gold and to grant immortality to those who used it. The legend was that this incredible substance was all around us which prompted Hennig Brand to try to obtain it from urine. He eventually distilled enough to form the material that glowed in the dark.
Today we are developing the methods to reclaim the small but significant amount in our urine. Over a 1000 litres are needed to retrieve less than 100 grams, but there are over 7 billion of us.
Brand was wrong about turning base metals into gold, but he may have been exactly right about it granting us immortality, if only we use it wisely.