Feeding ten billion people. three views.

Recent issues of Plant Physiology have contained a marvelous series of essays dealing with issues and controversies that surround the introduction and use of crops developed through the application of recombinant DNA technologies and genetically modified organisms (GMOs). These articles have provided considerable insight and thoughtful analysis of some of the major issues related to this timely topic. Among the points raised throughout these essays is the important role that GMOs will play as one of the components needed to enhance future agricultural productivity. Continued improvements in crop quality and productivity are crucial if we are to be in a position to feed the world of 10 billion people that will come into existence sometime after the middle of the current century. In the first essay in this series, Chris Somerville admonished plant biologists to make their voices heard in the ongoing GMO debate. However, plant biologists who make their voices heard on this issue, and that should include every member of the American Society of Plant Biologists, need to be knowledgeable on many aspects relating to GMOs, a number of which go beyond the science involved. One difficulty with many plant biologists in this regard is that we know a lot about the biology but often much less about the agricultural, sociopolitical, and economic issues that bear on the discussions surrounding GMOs. This is particularly true when talking about GMOs in terms of world agriculture. I will admit to having been relatively ignorant of agriculture worldwide myself until several years ago when I first read the book written by M.J. Chrispeels and D.E. Sadava, Plants, Genes and Agriculture, which remains an excellent primer on the topic. Recognizing this general deficiency, I would like to recommend three books to anyone interested in the larger topic of feeding the world’s population and in particular to those of you who are publicly engaged in the GMO debate. The first book, Feeding the Ten Billion: Plants and Population Growth, is written by Lloyd T. Evans. Evans is a crop physiologist from Australia and takes the interesting tack of following the progressive development of agriculture through time, going from a population of five million about 10,000 years ago, to the six billion reached a couple of years ago. Evans notes at the outset that the book is not meant to be an all-inclusive history of agriculture, and it is not. However, much agricultural history is woven throughout the fabric of the text in a very readable fashion. Evans also does a good job of illustrating how advances in our understanding of plant biology have been incorporated into agricultural practices. It is interesting that although plant physiology began to be applied to agriculture in a knowledgeable manner in the first half of the 19th century, until the advent of the Green Revolution after 1960, the major contributor to increases in the world food supply was the extension of arable land. Increased production since then has been obtained through rising yields, a feature that is beginning to show some signs of slowing down. The subject of arable land provides an illustration of why Evan’s book is worth reading. I have often seen it stated that most, or even all, of the arable land on the earth is already under cultivation, suggesting there is no more land available for that purpose. Worldwide, this is not true, but the actual situation is complex. There is a lot of potentially arable land that is currently not under cultivation but much of it is undisturbed forest and wetland, whereas other land is arable but marginal. Arable land is being lost all the time to urbanization and replaced with previously uncultivated land, keeping the total roughly constant. The book is filled with topics like this that will help the reader better understand the complexities of the issues related to producing enough food to keep up with population growth. Most plant biologists should come away from reading this book with a better sense of world agriculture in terms of where we are today, how we got there, and the constraints that will drive its development over the next 50 years. In a more philosophical vein, Evans begins the book by juxtaposing two views of the relationship between food production and population growth. The one view of Thomas Malthus has the supply of food being the driving variable and population growth dependent upon it and the other view is of Ester Boserup, who sees it the other way around, with population growth being the driver of agricultural development. Evans makes no attempt to resolve this issue, but keeps it front and center throughout the book and leaves it to the reader to ascertain which view might be closer to the truth. I would note that the correct answer, if one truly exists, would have a large bearing on the eventual acceptance of genetically modified crops, particularly in developing countries. The second book I recommend reading is Feeding the World: A Challenge for the Twenty-First Century by Vaclav Smil. Although the title is similar to that of Evans’ book, the approach is quite different. Smil