Mar 04 2014


A new article published in PNAS warns of, Increasing homogeneity in global food supplies and the implications for food security. They reviewed crop production worldwide over the last 50 years and found that:

“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.”

In other words, there has been a globalization of crop production, with more nations looking very similar to each other in terms of which crops they grow in what amounts. This has caused a shift to the major energy-dense crops (wheat, corn, rice, potatoes, and sugar) and a relative reduction in more nutrient dense foods. At the national level, species diversity remains high. However local varieties around the world are being displaced by the same energy dense crops internationally.

This has allowed countries around the world to increase their calorie production to help feed a growing human population. However, the trend also raises several concerns discussed by the authors.

One major concern is monoculture – the growing of a great deal of a limited number of varieties of crops. Crops that are ideal in terms of being profitable for farmers, convenient to grow with good yields, good store-shelf appeal, and long shelf life (which allows them to be transported a greater distance) have been favored. Since these traits have been prioritized, other traits have suffered, such as nutrient density, for example. These ideal crops have displaced to some degree local varieties. With the globalization of this process, local varieties around the world are being displaced by a small number of ideal crops.

One major problem of having our food supply increasingly dependent world wide on a smaller number of crops is that of vulnerability to crop failure due to pathogens or other disasters. One blight can wipe out a larger and larger segment of one year’s crop.

The authors are also concerned about the loss of genetic diversity as a source for future breeding of crops. Genetic diversity comes not just from having a wide variety of species and cultivars, but in planting them in sufficient amounts so that further diversity can develop.

One hedge against this problem is the so-called “doomsday vault.” So far the seeds of more than 20,000 species have been sent to this arctic vault to be frozen and preserved in case of emergency. The purpose of this vault is to preserve genetic diversity and ancestral forms as a stock of genetic material for breeding in the future.

The authors also worn about the health effects of having a food supply increasingly dependent on energy-dense rather than nutrition-dense foods. This problem is harder to quantify and connect the dots. The problems of obesity are more complex than just the availability of energy-dense food. Also, at the national level diversity remains high enough to provide varied nutrition, it’s mainly at the international level that diversity has been decreasing. In fact the globalization of the food supply allows for access to a greater variety of fruits and vegetables year round. I’m not saying they don’t have a point, but I don’t think we can make a straight connection between the data in this study and issues of obesity and nutrition.


The authors provide interesting data on the changes of global crop production, documenting what many have suspected – that our food supply is globalizing at the expense of local varieties. I don’t think it is practical to simply reverse this trend by asking farmers not to plant the most productive crops in favor of less productive local varieties. Rather, we need to balance the various demands of our global food production.

It does seem that we need to raise the priority of species diversity in our crops. Market forces seem to be pushing in the directions of increased monoculture and decreased global diversity. There does also appear to be a strong niche market, at least in wealthy countries, for heirloom varieties and other local novelty varieties. This is not enough, however, to offset the risks of major crop failure if a pathogen hit one of the major staple crops.

It is, of course, easier to point out problems than propose solutions. I am not sure what the best solutions would be, and I leave it to the experts to propose fixes. Perhaps incentivising farmers to add more diversity to their staple crops, or perhaps seed breeders to offer greater diversity.  These kinds of solutions are always tricky because of the law of unintended consequences. How much would this raise food prices, for example? Any solution is likely to have negative trade-offs, but it seems that our future crop security is worth exploring which trade-offs would be worth making.

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