Controversies in Science and Technology: From Maize to Menopause

10 Agricultural Biotechnology and the Environmental Challenge

10 Agricultural Biotechnology and the Environmental Challenge Peter H. Raven From 1950, when the world was inhabited by about 2.5 billion people, to 2000, the population has more than doubled, to six billion. How can we sustain human life on this planet as the population continues to grow? Today, although poverty is declining steadily in Asia and Latin America, approximately 1.2 billion people are living on less than $1 per day; in subSaharan Africa, almost half the people have an income at or below that level. About eight hundred million people in developing countries are chronically undernourished, a reduction of approximately forty million since 1990 but still a very large number; worldwide, the World Health Organization estimates that about half the population is malnourished for at least one critical dietary element. From 1970 to 1999, average food consumption per person increased in all regions, from 2,100 to 2,700 calories in developing countries, and from 3,000 to 3,400 calories in industrialized ones. The world population may become stable at a level of approximately nine billion people during the course of this century, but even that conservative estimate, combined with expectations for more affluence and consumption everywhere, poses enormous challenges for the world agricultural system. In an effort to supply these needs, about 11 percent of the world’s land surface is used to produce crops, a collective area about the size of South America, and only limited potential remains for expanding the area of land under cultivation. Most of the additional gains will be made in South 169 America and in sub-Saharan Africa, and they will be made only with the full application of all the tools available to agriculture. At the same time, about 20 percent of the land that was arable in 1950 has been lost subsequently , to salinization, desertification, urban sprawl, erosion, and other factors, so that farmers are feeding 6.3 billion people today on about four- fifths of the land from which they were feeding 2.5 billion people in 1950. That is possible through a combination of selection, breeding, improved irrigation systems, soil conservation, and the judicious application of fertilizers . Modern agriculture scarcely resembles the agriculture of the 1940s, and yet it is not able, partly for political and social reasons, to feed all people well. Beyond the land consigned to crop production, an additional 20 percent of the world’s land surface is used for raising animals, very critical in a world that is increasingly shifting to animal proteins. Most land used for agriculture and grazing, especially in the tropics and subtropics, is being degraded by these activities and is therefore becoming less sustainable and productive in the face of increasing worldwide demand for highquality food. In the world as a whole, human beings are estimated to be using, wasting , or diverting nearly half the total products of photosynthesis, which is essentially the sole source of nutrition not only for humans but for all the other organisms on Earth. In addition, people are consuming more than half the total renewable supplies of freshwater in the world. Agriculture accounts for about 90 percent of the total water consumed for human purposes, and we are unlikely to choose to maintain this relationship inde finitely as our population grows. In a world in which eight hundred million people receive so little food that their brains cannot develop normally and their bodies are literally wasting away; three billion people are malnourished; and in which 1.2 billion people live on less than $1 per day, the human population is supported by means of a gigantic and continuing overdraft on the world’s capital stocks of water, fossil energy, topsoil, forests, fisheries, and overall productivity . We use the world, its soils, waters, and atmosphere as a gigantic dumping ground for pollutants, including the pollutants that render much surface water unusable, the carbon dioxide that is contributing directly to global warming, and the atmospheric pollution that kills millions of people around the world annually. We are not living sustainably, and we can clearly find our way to a sustainable future only by achieving a sustainable 170 r av e n population, finding a sustainable level of consumption globally, accepting social justice as the norm for global development, and finding the improved technologies and practices that will help us make sustainable development possible. One of the most serious pressures on...