By Ronald Bailey
Avril 21, 2009
www.reason.com (lien to full column at Reason)
Why don’t environmentalists celebrate modern farming on Earth Day?
One might think that environmentalists would celebrate the accomplishments of modern farming on Earth Day. Après tout, the biggest way humanity disturbs the natural world is in how we produce food. Agriculture uses up more land and water than any other human activity. To the extent that we want to preserve biodiversity and protect natural areas, boosting agricultural productivity is the most vital thing that we can do.
Depuis 1960 global crop yields have more than doubled, with the benefit that the area of land devoted to producing food has not increased very much. If farmers were still producing food at 1960 levels of productivity, agriculture would have had to expand from 38 percent of the earth’s land to 82 percent to feed the world’s current population. This enormous increase in yields is the result of applying more artificial fertilizers, breeding higher yielding crops, a wider use of pesticides and herbicides, and expanding irrigation. Plus récemment, advances in modern biotechnology have also contributed to boosting yields. Cependant, La semaine dernière, the Union of Concerned Scientists (UCS) released a new report, Failure to Yield: Évaluation du rendement des cultures génétiquement modifiées, by its senior scientist Doug Gurian-Sherman that tries to make the case that modern crop biotechnology should be largely abandoned because it has failed to increase agricultural yields.
Failure to Yield begins by noting that, in the United States, 90 percent of soybeans and 63 percent of the corn crop are biotech varieties. Genes have been inserted in these varieties (called transgenic or genetically engineered by the report) to confer pest and herbicide resistance on the crops. The UCS study distinguishes between intrinsic yield, the highest yield possible under ideal conditions, and operational yield, the yield obtainable in the field taking into account factors like pests and environmental stresses. The study then asserts, "No currently available transgenic varieties enhance the intrinsic yield of any crops."
De plus,, Gurian-Sherman claims that biotech crops have only marginally increased operational yields for corn (largely through insect resistance traits) and not at all for soybeans in the United States.
Première, keep in mind that farmers are not stupid, and especially not poor farmers in developing countries. The UCS report acknowledges that American farmers have widely adopted biotech crops in the past 13 années. Pourquoi? "The fact that the herbicide-tolerant soybeans have been so widely adopted suggests that factors such as lower energy costs and convenience of GE soybeans also influence farmer choices." En effet. Surely saving fossil fuels that emit greenhouse gases should be viewed by a UCS advocacy scientist as an environmental good. And what does Gurian-Sherman mean by "convenience"? Par la suite, he admits that biotech herbicide resistant crops save costs and time for farmers. Herbicide resistance is also a key technology for expanding soil-saving no-till agriculture which, according to a report in 2003, enregistré 1 billion tons of topsoil from eroding annually. De plus,, no-till farming significantly reduces the run-off of fertilizers into streams and rivers.
The UCS report correctly observes, "It is also important to keep in mind where increased food production is most needed—in developing countries, especially in Africa, rather than in the developed world." Which is exactly what is happening with biotech crops in poor countries. Actuellement, 13.3 million farmers around the world are planting biotech crops. Notably, 90 percent of the world’s biotech farmers, C'est, 12.3 millions, are small and resource-poor farmers in developing countries like China, Inde, and South Africa. Gurian-Sherman is right that biotech contributions to yields in developed countries are relatively modest. Farmers here already have access and can afford modern agricultural technologies so improvements are going to be at the margins. Néanmoins, it is instructive to compare the rate of increase in corn yields between the biotech-friendly U.S. and biotech-hostile France and Italy over the past ten years. University of Georgia crop scientist Wayne Parrott notes, "In marked contrast to yield increases in the U.S., yields in France and Italy have leveled off."
The yield story is very different in poor countries. Par exemple, un 2006 study found that biotech insect resistant cotton varieties boosted the yields for India’s cotton farmers by 45 À 63 pour cent. Amusingly, some anti-biotech activists counter that these are not really yield increases, merely the prevention of crop losses. Bien sûr, another way to look at it is that these are increases in operational yields. Whether due to yield increase or crop loss prevention, dans 2008 this success led to nearly 70 percent of India’s cotton fields being planted with biotech varieties. De la même façon, biotech insect resistant corn varieties increased yields (or prevented losses) par 24 percent in the Philippines.
The UCS report also declares, "We must not simply produce more food at the expense of clean air, eau, sol, and a stable climate, which future generations will also require." Biotech varieties are already helping farmers to achieve those environmental benefits.
Gurian-Sherman notes that crops typically use only 30 À 50 percent of nitrogen fertilizers they receive. Nitrogen fertilizer contributes to water pollution and is the primary source of anthropogenic nitrous oxide, a greenhouse gas that is 300 fois plus puissant que le dioxyde de carbone. Agriculture contributes up to 12 percent of man-made global warming emissions. So one would think that a new biotech variety of rice created by Arcadia Biosciences, which needs 50 À 60 percent less nitrogen fertilizer than conventional varieties, would be welcomed by the UCS. But it isn’t. The really good news is that research into transferring this same set of fertilizer-thrifty genes into other crops is moving rapidly forward.
Another promising area of research involves using genetic engineering to transfer the C4 photosynthetic pathway into rice, which currently uses the less efficient C3 pathway. This could boost rice yields tremendously, perhaps as much 50 pour cent, while reducing water use. De plus,, researchers are pursuing all manner of other ways to boost crop production including salt, heat, and drought tolerance, along with viral, fungal, and bacterial disease resistance. All of these biotech techniques could improve crop productivity and thus reduce agriculture’s toll on land, eau, and air resources.
"To the extent to which groups like UCS have advocated prohibitive and disproportional regulations, they are responsible for the lack of even greater achievements in operational yield and perhaps even in intrinsic yield," notes Parrott. "In fact UCS is on the record as opposing engineered stress tolerance in crops. Such a stance by UCS is untenable and contradictory—yield losses caused by adverse growing conditions defeats the purpose of having a higher intrinsic yield—that is why it is so important to increase operational yield, and increasing operational yield is done with resistance to biotic and abiotic stresses—c'est-à-dire, adverse growing conditions."
Increasing crop yields to meet humanity’s growing demand for healthful food while protecting the natural world will require deploying the full scientific armamentarium. This includes advances in crop breeding, improvements in cultivation practices, the safer deployment of fertilizers, pesticides, and herbicides—et, Oui, genetic engineering. It is odd that while the UCS accepts the scientific consensus on man-made global warming, it refuses to accept the scientific consensus on the safety, usefulness, and environmental benefits of biotech crops.
"In the end, after helping prevent scientific advances with genetically modified crops," notes Parrott, "the UCS is not in a good position to be calling genetically modified crops a failure because their scientific advances have not been greater."
Ronald Bailey is Reason magazine’s science correspondent. His book Liberation Biology: The Scientific and Moral Case for the Biotech Revolution is now available from Prometheus Books.