Jaivime Evaristo*

P hosphorus is the basis for all life on Earth and is a key component in fertilizers in sustaining high crop yields, necessary in feeding a world

population of 9 billion people by 2050. Yet, of the four major plant nutrients – nitrogen, phosphorus, potas-sium, and sulfur – vital to growing crops for food, feed, and fiber, the global resource amount of phos-phorus is the least. Moreover, the world’s main source of phosphorus – phosphate rock – is non-renewable and is becoming increasingly scarce and expensive.

It was estimated that approximately 85 percent of the processed phosphorus worldwide is used as agricul-tural fertilizer and as a mineral source for animal nu-trition. This translates to 14.9 million tones (Mt)to nearly 19 Mt per year of phosphorus from mined phosphate rock for food production. However, a study in 2009 reported that only a fifth of this phosphorus actually reaches the consumers as food. The rest is lost, either permanently or temporarily, due to ineffi-ciencies in stages from mining through to processing and consumption. These studies, therefore, underline two key facts about the global phosphorus supply chain: (1) that there are huge opportunities for im-proving efficient use and reuse of phosphorus; and, (2) that sustained supply chain leakages could eventu-ally lead to rapid exhaustion of phosphate rock by which phosphorus and, therefore, global food security are anchored.

This op-ed piece compares and contrasts the concepts of “Peak Oil” and “Peak Phosphorus”; explores the concept of “Peak Phosphorus” by presenting evidence for and against the same; examines the potential ef-fects on the ecosystem and agribusiness if we reach “Peak Phosphorus”; comments on what should be done to avert a potential crisis as well as how busi-nesses are contributing to a more sustainable use of phosphorus across the supply chain.

The concepts Peak Oil and Peak Phosphorus are simi-lar in at least two key ways: (1) both are finite non-renewable resources, and 2) both concepts are predi-cated on Hubbert Linearization.

Hubbert Linearization models and predicts that non-renewable resources will follow a peak production curve, and that the point at which this production reaches its peak is followed by periods of lower-quality, harder-to-access reserves, which in turn can impact on prices of the commodity and associated products.

On the other hand, Peak Oil and Peak Phosphorus dif-fer also in at least two key ways: (1) while oil can be replaced by what is now considered as alternative sources of energy like solar, wind, geothermal, etc., there is no substitute for phosphorus in agriculture, and (2) while oil is unavailable once it is used, phos-phorus can be recovered in various stages in the glob-al food production and consumption system, and re-used within economic and technical limits.

The Chinese and the Japanese used human excreta or “night soil” as a fertilizer for centuries prior to the In-dustrial Revolution. When the German chemist, Justus von Liebig, formulated his “mineral theory” in 1840, it confirmed that the fertilizing effect of humus on plant growth was due to inorganic salts of phos-phorus and nitrogen, and not organic matter or some mysterious ways as previously thought. Liebig’s theory was widely adopted which led to the growth of phos-phorus fertilizer manufacturing in 18th-century Eu-rope in a manner where the feedstock was sourced from locally available waste products such as human excreta, industrial organic waste by-products, animal dung, and other slaughter by-products.

However, the highly localized model of phosphorus

*Author Jaivime Evaristo is pursuing Hydrogeolo-

gy in the Master of Science in Applied Geosciences

program at the University of Pennsylvania.

**IGEL is a Wharton-led, Penn-wide initiative to

facilitate research, events and curriculum on busi-

ness and the environment. IGEL Research Briefs

are written by students on relevant issues in busi-

ness and the environment. Learn more at http://

environment.wharton.upenn.edu

fertilizer production was later replaced by the im-portation of phosphorus materials during the mid-to-late 19th century as demand grew steadily with industrialization and rapid urbanization. This shift culminated in the mining and processing of phos-phate rock, which was regarded as an “unlimited source” of concentrated phosphorus. Together with milestone developments decades prior to the Green Revolution of the mid-20th century – especially the Haber-Bosch process in artificial nitrogen fertilizer production – phosphate rock mining and pro-cessing led to the rapid development of mineral fer-tilizer production.

However, the Sanitation Revolution, which started in mid-19th century and evolved as a response to the health hazards posed by the old practices in waste management, fundamentally changed the way wastes were disposed. Moreover, as the distances between cities and agricultural fields increased, the focus shifted from land-based to water-based dis-posal of “waste” thereby effectively transforming the phosphorus flow in agriculture from a closed-loop, phosphorus-recycling system to a linear, through-put system. The problem with this linear system is not only that it poses threats to environmental qual-ity and biodiversity as a result of phosphorus (and nitrogen) contamination in the bodies of water but also that it is unsustainable – considering the finite nature of phosphate rock.

Therefore, we can say that the main argument for Peak Phosphorus is centered on the finite nature of phosphate rock reserves; and, that the rate by which the world approaches this “peak” is a function of both the phosphate rock reserves and a sustained, if not an ever-expanding, linear, throughput system. To be able to appreciate the arguments for Peak Phosphorus, let us quickly examine some salient features of the latter two factors.

1. Global phosphate rock reserves The main phosphate rock reserves are found in just a few countries like Morocco, China, and the United States. Across the EU, the only oper-ational source of phosphate rock is a relatively small mine in Finland. The Peak Phosphorus concept argues that the critical point is not when 100% of the reserves are depleted, but ra-ther when the high quality, easily accessible re-serves have been depleted. Already, some stud-ies report that the remaining phosphate rock is lower in phosphorus concentration (%P2O5), higher in contaminants, and more difficult to access, thereby requiring more energy to extract and produce, and more money to refine and ship.

Fig. 1. Indicative Peak Phosphorus curve, illustrating that global P reserves are also likely to peak after which produc-tion will be significantly reduced (Jasinski, 2006; European Fertilizer Manufacturers Association, 2000). Source: Cordell et al. (2009)

Proponents of Peak Phosphorus argue that these devel-opments affecting the phosphorus fertilizer industry all point to the inevitability of a global peak in phosphorus production between 2030 and 2040 (see Fig. 1).

2. An ever-expanding linear phosphorus system As stated earlier, only a fifth of the phosphorus from mined phosphate rock is actually consumed by hu mans as food. Phosphorus losses from the farm due to erosion are estimated at around 8 Mt per year; from crops due to pests, diseases, wild animal con sumption, force majeure, etc. at 3 Mt per year; from post-harvest at 0.9 Mt per year, from the food com modity chain due to losses in distribution, retail, household or institutional food waste at 1 Mt per year. In addition, a total of 2.7 Mt per year is estimated as phosphorus lost during mining and fertilizer produc tion. On the other end of the supply chain, of the 3 Mt per year of phosphorus consumed by humans, an esti mated 2.7 Mt is lost to landfills and non-arable soil as well as to inland or coastal waters. Overall, a total of 18.3 Mt per year of phosphorus is being lost mostly ending up in bodies of water thereby resulting in en vironmental problems like eutrophication.

In summary, according to the proponents of the Peak Phos-phorus concept, the finite nature of phosphate rock and this “leaky”, unsustainable linear model only hasten the inevita-bility of Peak Phosphorus.

It is important to stress that there is agreement from both sides of the Peak Phosphorus debate that the supply of phosphate rock will eventually be-come scarce. Therefore, what the skeptics are argu-ing against the Peak Phosphorus concept is not the fundamental and inevitable exhaustibility of the phosphate rock reserves but the actual timing of reserve exhaustion.

The non-profit International Fertilizer Develop-ment Center (IFDC) conducted a major survey of global PR resources and reserves, which was pub-lished in September 2010. A notable feature of the study was the attempt to standardize the use of the reserve-resource terminology. IFDC defines a “reserve” as phosphate rock that can be economical-ly produced at the time of the determination to make suitable products, reported as tons of phos-phorus concentrate. This definition implies that “reserves” are dynamic. On the other hand, a “resource” is that phosphate reserve of any grade that may be produced at some time in the future, including reserves. The study found that as of 2010, the world has some 60,000 Mt of reserves (phosphate rock product) and 290,000 Mt of re-sources (ore potential). These numbers are in stark contrast to the 16,000 Mt reserves estimated by the USGS in 2010.

While proponents of Peak Phosphorus use the in-creasing prevalence of lower-grade phosphate rock as evidence for imminent Peak Phosphorus, the skeptics use the same as evidence to the contrary. For example, in the past, phosphate ore grades were sought at 70 Bone Phosphate of Lime (BPL) or higher. Today, lower BPL grades of 50 and below are being mined. IFDC argues that this explains the significant difference in estimates between the USGS and IFDC. An example of this would be Mo-rocco, which according to the USGS has some 5,700 Mt of reserves left, but which the IFDC estimated to still have 51,000 Mt. Resource wise, IFDC estimat-ed Morocco to have significantly even more at 170,000 Mt.

The 2010 IFDC Study concludes that assuming cur-rent rate of production, the world phosphate rock concentrate reserves are available to between 300 and 400 years, considerably longer than most stud-ies including the USGS (2010) estimate. It adds that there is no indication that a Peak Phosphorus event will occur in the next 20 to 25 years, contrary to the ones proposed by a number of scientists.

On a slightly different note, some experts have ad-dressed with optimism the challenges of lower-grade phosphate rock. They suggest that market forces will lead to new technologies to improve the efficiency of phosphate rock extraction and beneficiation.

And perhaps most important of all developments that the Peak Phosphorus skeptics might consider as an “added boost” to their argument is the recently revised phosphate rock reserve-resource estimates by the USGS. In January 2011, as a result of the 2010 IFDC Study and new data from Morocco, the USGS revised the world reserve estimates from 16,000 Mt in 2010 to 65,000 Mt in 2011.

In summary, according to skeptics of the Peak Phospho-rus concept, phosphorus will eventually run out – just not as quickly as Peak Phosphorus proponents suggest-ed.

In addition to some inherent environmental conse-quences of phosphate rock mining and processing – i.e. greenhouse gas emissions from mining through to pro-cessing and transport – as well as the problem of eu-trophication due to the leakage of phosphorus into in-land and coastal waters, it can be inferred that one of the desired or beneficial main effects of a hypothetical Peak Phosphorus world would be reduced eutrophica-tion and a mitigated or averted ecosystem degradation – all because of a consequently reduced phosphorus in-puts into the system. Although market forces, as argued by some experts, will encourage the development of new technologies to improve the efficiency of phosphate rock extraction and beneficiation; theoretically, a long-term decline in phosphate rock production will at this point become inevitable. Then, as phosphate rock production declines and therefore phosphorus fertilizer production, the demand for food from a growing population will hopefully result in heightened and integrated measures to recover phosphorus losses and reuse of the same in the global food production and consumption system.

Environmentally, a Peak Phosphorus world would be beneficial given the linear phosphorus fluxes from a food production and consumption system that is struc-

““Along with peak oil and water short-ages, the prospect of peak phosphorus in the context of a global climate change could pose serious security

risks to a lot of countries.””

turally “leaky”, unsustainable, and ecologically dis-astrous.

However, on the agribusiness side, a Peak Phospho-rus world would be catastrophic because a growing scarcity of phosphorus – along the confluence of resource pressures from a growing population and the absence of sustainable phosphorus recovery and reuse technologies and policies – could only mean higher food prices and, therefore, a volatile global food security system. Along with peak oil and water shortages, the prospect of peak phosphorus in the context of a global climate change could pose seri-ous security risks to a lot of countries.

First of all, the debate around phosphorus should elevate from the level of “Peak Phosphorus timing” to one that collectively recognizes the finite and ex-haustible nature of phosphate rock reserves – re-gardless of whether a conceptual “peak” is coming in the next 20, 30, 100, or 400 years. As a recent study succinctly put it: the fate of humankind on this planet may, indeed, rest on this recognition fac-tor. Secondly, a multi-faceted approach needs to be employed in increasing phosphorus use efficiency, recovery, and reuse (see Fig. 2). Scientists from a recent study used a systems framework for phos-phorus recovery and reuse options. They reported that meeting long-term phosphorus demand would likely require demand management measures to increase phosphorus use efficiency by two-thirds, and the remaining third could be met through a high recovery rate of phosphorus from human ex-creta, manure, food waste, and mining waste. Given how far modern societies have changed from a closed-loop phosphorus-recycling system to a pre-sent-day linear or open system, it is clear that transitioning back to a high phosphorus recov-ery and reuse society could entail significant financial, technological, and political invest-ments.

Fig. 2. A sustainable sce-

nario for meeting long-

term future phosphorus

demand through phos-

phorus use efficiency and

recovery. Source: Cordell

et al. (2009)

Fig. 2 illustrates how more can be achieved from demand management measures; however, already significant improvements can also be achieved just by managing what we now so readily dump into landfills and waterways. For example, there are al-ready some commercially viable processes for the precipitation of phosphorus from effluent water streams. Companies like Ostara in Canada, with support from a major company in the wastewater sector, Veolia Environnement, already has the tech-nology to recover phosphorus in a form – struvite – suitable for use as fertilizer. Struvite has been shown to be as available to plants as from triple su-perphosphate commercial fertilizer.

In the US, Ostara has three commercial nutrient re-covery facilities: in Portland, Oregon; in Suffolk, Virginia; and, in York, Pennsylvania. The company also expects to see the construction completion of Europe’s first phosphorus recovery plant for the UK’s Thames Water at its Slough Sewage Treatment Works. This facility will “recover phosphorus and ammonia from wastewater streams and transform them into environmentally-friendly, premium-quality fertilizer”. Across the world, various collabo-rative models have emerged with the vision of accel-erating technological innovations and ensuring commercial viability in terms of phosphorus recov-ery and reuse. As “green technologies” are all en-riched in innovations and as demand for these prod-ucts and services grows – partly due to evolving reg-ulatory policies – opportunities for start-ups and venture capitalists proportionately abound. In the end, it appears that the optimal way to effect change on the environment is to tap on the fountain of col-laborative ingenuity at the start-up level; as well as on the existing know-how and resources of busi-nesses and ancillary systems like private equity and venture capital.

The growth in available scientific literature about phosphorus use efficiency, recovery, and reuse in the last 10 to 15 years – whether or not in explicit contexts of the Peak Phosphorus argument – points to a pressing need for managing this finite, albeit recoverable, precious resource. Any sigh of relief brought about by new and revised estimates of global phosphate rock reserves by expert au-thorities is only ephemeral. Unless we do some-thing – or a myriad of things – on the demand side; and/or put plugs on the “leaks” across the global food production and consumption system, we will inevitably reach Peak Phosphorus and usa-ble phosphorus exhaustion at some point in the future. Whether that “some point” is 30, 100, or 400 years is almost beside the point if we are to uphold the values of transgenerational responsibil-ity and empathy. Clearly, it is in our best interests if we start widespread advocacies for more sus-tainable, ecologically beneficial practices in man-aging our waste streams today. Just as some tech-nocrats trust that market forces will eventually find better ways of managing the threats of phos-phate rock exhaustion, the same market forces could also drive a consequential commercializa-tion and institutionalization of existing and future technologies in recovering phosphorus from our sewers, reducing leakage during mining and pro-cessing, and increasing phosphorus retention in our arable soils. The concept of Peak Oil imparts a lot of lessons for mankind with respect to phos-phorus. The debate henceforth needs not to be about “peak timing” but about peak aversion and therefore more scientific research to better aid pol-icy formulation and integration in a theoretic but effectively pragmatic, cradle-to-cradle

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