Peak Phosphorous - A Looming Food Crisis

There is a looming food crisis in the world that is hardly ever mentioned. It could be labelled a new inconvienient truth. Phosphorous is one of the most important nutrients and is essential to all biological life. In most farming, phosphorous is added using fertilizers. Unlike nitrogen, which the other important nutrient, phosphorous supplies are much more limited. Phosphorous used in fertilizers is mainly provided from mining.

Before the rise of modern farming using fertilizers, phosphorous cycled in a closed loop, see figure. But by mining more and more phosphorous, humanity has disturbed the natural cycle and the phosphate minerals are used up at a quick pace.

So how bad is this? When will we see the peak of global phosphorous minig? What can we do to solve the problem? In the rest of this post, I will try to answer those questions.

Currently, we are dependent on continous input of artificial phosphate fertilizer to maintain soil fertility. As crops are harvested, phosphorous is taken off the fields and rarely brought back. There are various estimates of the remaining phosphorous deposites. They typically range from 50 to 150 years. That is, our children or grandchildren will probably face failing, or even depleted, deposites.

In the last 150 years, we have constantly been aiming to increase crop sizes. This has been done by breeding plants that grow well in an environment where nutrients are present in large quantities. These plants may not grow well if we try to give them less nutrients. There are seed banks in the world containing seeds from old crops, but these might not be good enough either. Not even by breeding new plants can we secure food production for a population of maybe nine or ten billions.

What we need to do in order is to secure future food supply is to once again close the loop. We have to create an artificial phosphorous cycle. We need to start using human excrementa as fertilizer in one way or the other. The peepoo bag is one solution for both this problem and an other, much more urgent problem. Today, 2.6 billion people lack access to satisfying sanitary facilities. The safe and easy to use peepoo bag uses no water and removes the risk of pathogens from human faeces contaminating water causing ch***ra and other serious infections. The bag is biodegradable and can easily be used as fertilizer.

For a country like my own, Sweden, there are other solutions being developed for returning nutrients to the fields. Swedish authorities estimate that the phosphorous content in sewage sludge corresponds to 40 per cent of the annual use of artificial fertilizers. The project called REVAQ aims to certify sewage sludge for use as fertilizer. Its goal is that by 2015, 60 per cent of sewage sludge should be used as fertilizer. More about using sewage sludge as fertilizer can be found in the first and second EU sludge summary reports.

In addition to using human excrementa as fertilizer, we will also have to stop leakage and runoff from fertile soils. In Sweden, it is important not to spread fertilizer over frosen soils. It also very important not to use more fertilizer than needed.

I really think that this problem can be solved. But to do so, we must not forget about it. We will never be able to lift the bottom billion out of poverty if we cannot provide enough food. Solving this problem will also require solving the more urgent need for sanitation; therefore, there is no time to wait!