New projection of Peak Phosphorus

NOTE: Images in this archived article have been removed.

In 2007, we published one of the first papers on peak phosophorus, and since then have monitored coverage of the subject.

Now a detailed projection of phosphorus production by two Australian researchers indicates that world phosphate rock production will most likely peak in 2027. Below is a summary of the paper, Projections of Future Phosphorus Production, originally published at Philica.com .A PDF of the full paper is available at the Resilience website.

Co-author Steve Mohr is a Senior Research Consultant at the Institute for Sustainable Futures. He has "developed the GeRS-DeMo – or Geologic Resource Supply-Demand Model that estimates the demand, production (from mines or fields) and recycling of any geologic resource. Specifically, it can be used to predict the historic and future production, amount of recycling and demand of a metal, fossil fuel, or mineral." In 2010, we published his Projection of world fossil fuel production. To see more projections for resources in general, go Mohr’s bio page and click on the GeRS-DeMo link.

Co-author Geoffrey Evans is a professor at the School of Engineering, University of Newcastle.

– BA

Phosphorus and its compounds are used in fertilisers, animal feed, detergents, and metal treatment operations (Steen, 1998). More than 80 percent (Steen, 1998; Cordell et al., 2009; Van Vuuren et al., 2010) of the phosphorus produced is utilised in fertilisers to assist in crop production, resulting in increased yields of up to 50 percent (Stewart et al., 2005). Without the use of fertilisers it would be difficult to provide sufficient food for an expanding world population, which is projected to grow from around 0.9 billion in 1850 (Kremer, 1993) to 9 billion in 2050 (U.N., 2008). Corresponding to the increase in population has been an annual increase in phosphorus production, from less than 1 Mt (P)/y in 1850 to 22 Mt (P)/y in 2012. Currently, the current cumulative production of phosphorus, mined from phosphate rock and guano, is estimated to be approximately 954 Mt (P). Phosphorus is a finite resource and cannot be substituted for agricultural uses (USGS var.). Hence it is essential that the resource be managed in order to avoid, or mitigate at least, any future supply limitation. To do this, reliable estimates of future demand and realistic projections of production rates are required based on the amount of phosphorus that remains.

For predicting future supply the ultimately recoverable resource (URR) is commonly used and is equal to the combined sum of all historic and future production. Estimates of URR values for phosphorus currently range from 1,000 to 36,700 Mt (P) (Cordell et al., 2009; Déry and Anderson, 2007; Ward, 2008; Van Vuuren et al., 2010). Such a broad range in URR estimates highlights the uncertainty in the quantity of phosphorus-bearing material actually available. Future production projections also have a wide variation as they are dependent on both the amount of the recoverable resources still remaining as well as external drivers, such as droughts, wars, famines, etc, that influence annual production.

In this article, Mohr and Evans collate phosphate rock production statistics for all countries and apply GeRS-DeMo (Geologic Resource Supply-Demand Model) to estimate future production for three distinct scenarios. The Low scenario used Hubbert Linearisation to determine the Ultimately Recoverable Resources (URR). The High scenario combined the highest resources estimates and a 60% recovery factor with historical production. Finally the Best Estimate scenario reflected the authors best estimate as to the correct URR values. The URR estimates used were: 2010, 4181 and 9197 Mt (P) for the Low, Best Estimate and High scenarios respectively.

The demand-production interaction resource model of Mohr (2010) which previsous has been used to model fossil fuels was used to create a country-by-country projection phosphorus production. The model has two distinct modes of operation, Static in which supply and demand do not influence each other, and Dynamic were supply and demand do interact with each other. By applying this model, phosphorus production was projected to peak in 2020/21, 2027 and 2118 for the Low, Best Estimate and High scenarios, as shown in Figure 1.


(a1) Static: Low	(b1) Dynamic: Low

(a2) Static: Best Estimate	(b2) Dynamic: Best Estimate

(a3) Static: High	(b3) Dynamic: High

Figure 1: Phosphorus demand-supply vs time

In both the Best Estimate and Low scenarios indicate that peak phosphorus will occur within 15 years. Although the High scenario peaks after 2100 it is important to recognise that Morocco/Western Sahara accounts for almost 70% of the High scenarios URR. Indeed the World excluding Morocco/Western Sahara production peaks in 2030. Further by 2100, virtually all of the world’s production will occur from Morocco/Western Sahara only.

The vulnerability to any kind of disruption in Morocco/Western Sahara after the rest of the world has peaked has been investigated by implementing a hypothetical 10 year disruption to supplies in the country starting in 2040. The effect of this simulated disruption is shown in Figures 2 and 3.

Figure 2: Number of mines in operation in Morocco with and without a disruption

Figure 8: Morocco and World supply with and without a disruption

It can be seen that the 10 year disruption for the Morocco/Western Sahara region results in an annual decrease of 6-11 Mt (P)/y in world phosphorus production that continues for many decades after the cessation of the disruption.

Historically, almost all of the phosphorus has been utilised as a single use from mined resources. As shortages occur, as the modelling has shown, alternative approaches will be required, including increased recycling, greater efficiency of use in the food production cycle, and finding replacements for non-essential uses such as detergents, chemicals, etc.

The Electronic Supplement accessible freely on the Philica website contains both the production statistics collated for this work and the models used for this article.

Mohr, S. & Evans, G. (2013). Projections of Future Phosphorus Production. PHILICA.COM Article number 380.

Cover image of phosphorus atom from Wikimedia Commons: http://commons.wikimedia.org/wiki/Phosphorus