Increasing homogeneity in global food supplies and the implications for food security
- aInternational Center for Tropical Agriculture, Apartado Aéreo 6713, Cali, Colombia;
- bCentre for Crop Systems Analysis, Wageningen University, 6708 PB, Wageningen, The Netherlands;
- Departments of cGeography and
- eBotany,
- dThe Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada V6T 1Z4;
- fGlobal Crop Diversity Trust, 53115 Bonn, Germany;
- gCGIAR Research Program on Climate Change, Agriculture, and Food Security, Cali, Colombia;
- hInstitute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom; and
- iDepartment of Biology, Indiana University, Bloomington, IN 47405
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Edited by Stephen Polasky, University of Minnesota, St. Paul, MN, and approved January 29, 2014 (received for review July 17, 2013)

Significance
This study provides evidence of change in the relative importance of different crop plants in national food supplies worldwide over the past 50 years. Within a global trend of increased overall quantities of food calories, protein, fat, and weight, and increased proportions of those quantities sourcing from energy-dense foods, national food supplies diversified in regard to contributing measured crop commodities. As a consequence, national food supplies globally have become increasingly similar in composition, based upon a suite of truly global crop plants. The growth in reliance worldwide on these crops heightens interdependence among countries in their food supplies, plant genetic resources, and nutritional priorities.
Abstract
The narrowing of diversity in crop species contributing to the world’s food supplies has been considered a potential threat to food security. However, changes in this diversity have not been quantified globally. We assess trends over the past 50 y in the richness, abundance, and composition of crop species in national food supplies worldwide. Over this period, national per capita food supplies expanded in total quantities of food calories, protein, fat, and weight, with increased proportions of those quantities sourcing from energy-dense foods. At the same time the number of measured crop commodities contributing to national food supplies increased, the relative contribution of these commodities within these supplies became more even, and the dominance of the most significant commodities decreased. As a consequence, national food supplies worldwide became more similar in composition, correlated particularly with an increased supply of a number of globally important cereal and oil crops, and a decline of other cereal, oil, and starchy root species. The increase in homogeneity worldwide portends the establishment of a global standard food supply, which is relatively species-rich in regard to measured crops at the national level, but species-poor globally. These changes in food supplies heighten interdependence among countries in regard to availability and access to these food sources and the genetic resources supporting their production, and give further urgency to nutrition development priorities aimed at bolstering food security.
Footnotes
- ↵1To whom correspondence should be addressed. E-mail: c.khoury{at}cgiar.org.
Author contributions: C.K.K. and H.D. designed research; C.K.K., A.D.B., and J.R.-V. performed research; C.K.K., A.D.B., and J.R.-V. contributed new reagents/analytic tools; C.K.K., A.D.B., H.D., J.R.-V., L.H.R., and P.C.S. analyzed data; and C.K.K., A.D.B., H.D., J.R.-V., L.G., A.J., L.H.R., and P.C.S. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1313490111/-/DCSupplemental.
Freely available online through the PNAS open access option.