95th ESA Annual Meeting (August 1 -- 6, 2010)

COS 22-1 - Phosphorus, food, and future challenges: Sustainable solutions to avoiding famine through closing the human phosphorus cycle

Tuesday, August 3, 2010: 8:00 AM
336, David L Lawrence Convention Center
Daniel L. Childers1, Jessica Corman2, James J. Elser2 and Mark Edwards3, (1)School of Sustainability, Arizona State University, Tempe, AZ, (2)School of Life Sciences, Arizona State University, Tempe, AZ, (3)W.P. Carey School of Business, Arizona State University, Tempe, AZ
Background/Question/Methods
Industrialized agriculture is a dominant and highly visible feature of the current Anthropocene Epoch. This “Green Revolution” followed agronomic innovations coupled to invention of the Haber-Bosch process, which allowed humans to fix atmospheric nitrogen (N) for fertilizer, and is responsible for a three-fold increase in food production in the last 50-75 years. However, it is not well appreciated that these increases in crop production also required a concurrent increase in the use of inorganic phosphorus (P) that have been met by a massive expansion of P-rich mineral deposit mining. Industrial N-fixation may be rendered sustainable in the long-term if its dependence on fossil energy is minimized. However, a sustainable P supply is not assured because P deposits are regenerated only on geologic time scales.

Results/Conclusions

In short, the current model for food production is dependent on P supplies that are effectively non-renewable and are being depleted. Notably, because all life depends on P, it is effectively a non-substitutable necessity for both humans and the ecosystems on which we depend. Furthermore, mineral P deposits are not distributed evenly across the earth, suggesting that future P scarcity [and associated limitations on food production] may have national security implications. Indeed, some projections show mineral P reserves being depleted within decades—a prediction that is exacerbated by the increasing prevalence of P-rich diets worldwide and the expanding biofuels demand for P fertilizers. Phosphorus-induced famine is thus within the realm of possibility, particularly in developing countries where subsistence farmers are very sensitive to commodity prices. Such a future is ominous, but sustainable solutions to P challenges exist. Fundamentally, these solutions involve closing the human P cycle. We review the current state of knowledge about human P use and dependence and present examples of sustainable solutions in the context of the human P cycle.