A column by legendary asset manager Jeremy Grantham is more suitable for the tabloids than for one of the world’s oldest and most prestigious scientific weekly magazines.
His direst example is “the impending shortage of two fertilizers: phosphorus (phosphate) and potassium (potash). These two elements cannot be made, cannot be substituted, are necessary to grow all life forms, and are mined and depleted. It’s a scary set of statements…. What happens when these fertilizers run out is a question I can’t get satisfactorily answered and, believe me, I have tried.’’ Well, he could have tried just a bit harder: an Internet search would have led him, in mere seconds, to “World Phosphate Rock Reserves and Resources,” a study published in 2010 by the International Fertilizer Development Center (IFDC) and funded by the U.S. Agency for International Development.
This detailed assessment of the world’s phosphate reserves (that are the part of a wider category of resources that is recoverable with existing techniques and at acceptable cost) concluded that they are adequate to produce fertilizer for the next 300 to 400 years. As with all mineral resource appraisals (be they of crude oil or rare earths), the study’s conclusions can be criticized and questioned, and the statement by the Global Phosphorus Research Initiative is perhaps the best document of that kind. But even the most conservative interpretation of IFDC’s assessment shows that phosphates have a reserve/production ratio well in excess of 100 years, higher than that of many other critical mineral resources.
Even the most conservative interpretation of IFDC’s assessment shows that phosphates have a reserve/production ratio well in excess of 100 years, higher than that of many other critical mineral resources.
Grantham could have also checked the standard, and the most often quoted, sourcebooks on the world’s mineral resources, Mineral Commodity Summaries, published annually by the U.S. Geological Survey (USGS). In the latest edition, he would have found that the USGS made significant revisions to its phosphate rock reserves data for Morocco, Russia, Algeria, Senegal, and Syria, and that it now puts the global reserve/production ratio at about 370 years. Or he could have consulted the materials put out by the International Fertilizer Industry Association, whose members include many of the world’s most prominent fertilizer producers, traders, and shippers. The association (emphasis in the original) “does not believe that peak phosphorus is a pressing issue, or that phosphate rock depletion is imminent. Nevertheless, it believes that efforts to minimize phosphorus losses to the environment and optimize phosphorus use should be encouraged.’’
And that is precisely as it should be, because wasteful use of all kinds of fertilizers is common and optimizing the applications brings substantial monetary and environmental rewards (phosphates are a major cause of aquatic eutrophication, their worst effects are persistent dead zones in many coastal areas around the world). Larger gains in reducing phosphate applications could be made by moderating typical per capita meat consumption, and a great amount of the element can be recovered from waste. In all Western countries, most fertilizers are now applied to feed not food crops, and hence moderating the current high rates of meat consumption (commonly in excess of 100 kg per capita) would reduce the amount of needed fertilizer. Such cuts would also have environmental and health benefits.
An even more important option – especially given the facts that much of modern meat, milk, and egg production is done in a concentrated manner, and that half of the world’s population lives in cities – is now available thanks to advances in phosphorus reuse from manures and municipal wastes. Grantham could have talked to many experts in this flourishing field, or could have simply consulted the SCOPE Newsletter, which reports, several times every year, the latest scientific and commercial achievements regarding phosphorus recovery. In the latest issue of this newsletter he would have also learned that the world has, at the current rate of consumption, about 600 years of minable potassium reserves.
Grantham cannot dismiss all of this as just usual propaganda put out by the fertilizer industry. That a financier and asset manager – whose expertise does not include resource geology, soil science, plant science, or agronomy – comes to “only one conclusion,’’ namely that the use of fertilizers “must be drastically reduced in the next 20–40 years or we will begin to starve,” is as wrong as it is understandable. Clearly, he was after sensational headlines and, indeed, in his column he implores scientists to engage in “overstatement’’ and to be arrested (if necessary) in order to call attention to the imminent perils he describes. That the world’s leading scientific journal prints such tabloid talk is harder to comprehend. Do we not have science precisely in order to provide us with the best available evidence so we can understand the real challenges and make well-informed decisions to pursue the most responsible and the most effective solutions?
Vaclav Smil does interdisciplinary research in the fields of energy, environmental and population change, food production and nutrition, technical innovation, risk assessment, and public policy.