Source – Forbes.com
By Graham Brookes and Henry I. Miller
Date – 13 Feb 2013
Website – www.forbes.com
Groundbreaking new technologies commonly face intractable opposition from various quarters–often from vested interests or societal Cassandras. The anti-vaccination movement has been active since immunization against disease began in the 18th century and perseveres–in spite of the fact although vaccines are extraordinarily safe and effective, and with the exception of safe water, no other public health intervention has exerted as profound an effect on humans’ longevity.
Fluoridation of water has been another lightning rod although there is overwhelming evidence that the practice has dramatically improved the oral health of scores of millions of Americans; in fact, the Centers for Disease Control and Prevention designated community water fluoridation one of the ten most significant public health achievements of the 20th century.
Genetic engineering applied to agriculture has suffered a similar fate since it emerged on the scene about two decades ago. The technology, technically called recombinant DNA technology and also known as “gene-splicing” or “genetic modification” (GM), already has made tremendous contributions to agriculture, particularly among small farmers in poor countries. Although such genetic engineering is essentially an extension, or refinement, of techniques that have been around for centuries, it has led to less use of chemical pesticides, a drop in pesticide poisoning of farmers and their families, more environment-friendly agronomic practices and greater profits for farmers. In the near future, we can expect new plant varieties that conserve water or produce valuable substances such as nutrients, drugs and vaccines. (For example, anti-rabies-virus antibodies were recently produced ingenetically engineered tobacco plants.)
However, it seems that no good deed goes unpunished, and genetic engineering continues to be the target of spurious claims based not only on activists’ imaginings but also on poorly designed experiments that are over- and misinterpreted. (Numerous articles at http://www.biofortified.org/debunk many of the inaccurate assertions about genetic engineering.) A recent example is an article by Washington State University-based academic Charles Benbrook, a long time organic farming advocate and critic of genetic engineering, which contains a number of broad claims relating to negative health and environmental impacts associated with the use of genetically engineered crops in the United States.
The data on which Benbrook relied do not, in fact, support his conclusions. His work exemplifies the observation of biologist James F. Bonner, who once said about the research results of a competitor that did not agree with his own, “There are a thousand ways to do an experiment wrong.” Benbrook has found many of those ways, and his recent article serves as a case study of how to bend the data to support a preordained (and insupportable) conclusion.
According to Benbrook, the negative effects of genetic engineering have resulted from the widespread adoption by farmers of crops such as corn and soybean engineered to be resistant to the herbicide glyphosate. He claims that his conclusions are derived from his analysis of official United State Department of Agriculture (USDA) pesticide-use data; that there are few other comprehensive estimates of the impacts of genetically engineered herbicide-tolerant crops on herbicide use; and that other researchers who came to completely different (opposite) conclusions erred when they examined the impacts of changes in pesticide use with genetically engineered crops. In other words, Benbrook believes that the other, contrary analyses – which unlike his own, used accepted, valid research practices — were flawed.
He is wrong on all counts and, as with other false alarms about the hazards of genetic engineering sounded in recent years, there is both more and less to the Benbrook story than meets the eye.
While at his previous position at the U.S. Organic Center, which is ideologically and intractably (and irrationally) opposed to genetic engineering, Benbrook authored many other papers with similar claims about genetic engineering. None were published in reputable peer-reviewed journals and when independently assessed, they were invariably exposed as being misleading and inaccurate. From his new perch in academia, Benbrook has sought credibility by managing to get one of his ideological screeds into a peer-reviewed journal.
But all peer review is not created equal, and it is deficient more often than many realize. This most recent Benbrook article would likely have failed peer review by the vast majority of experts in this field. Its most serious flaws are discussed below.
Flawed methodology that introduces bias. A critical flaw in Benbrook’s approach is his use of the amount (weight) of herbicide active ingredient applied as the sole measure of environmental (and health) impact, although this is a poor indicator. It is analogous to equating the amount of a medicine ingested with potential harmful effects without considering its toxicity. The total volume of herbicides used with genetically engineered, herbicide-tolerant crops in the United States may have increased relative to usage levels 10 years ago, but because the herbicides used with genetically engineered, herbicide-tolerant technology are less harmful to the environment than the ones they have replaced, the increase in amount used is inconsequential. What matters for the safety of consumers and the environment is the net effect of the change. The peer reviewed literature contains many more appropriate and valid approaches to assessing health and environmental impacts than the amount of herbicide applied to crops.
It is not surprising, therefore, that other investigators who have used more relevant measures of impacts have come to different conclusions – namely, that the cultivation of genetically engineered, herbicide-tolerant crops has resulted in net environmental benefits. Benbrook omits any discussion of these issues or of alternative parameters to measure environmental impact.
Benbrook also fails to mention that by improving weed control and reducing the need for ploughing, genetically engineered herbicide-tolerant crops enable many farmers in North and South America to adopt and maintain no- or reduced-tillage production systems, which results in important reductions in greenhouse gas emissions. For example, the adoption of genetically engineered, herbicide-tolerant crops just in the United States contributed in 2010 to the equivalent of removing 11 billion pounds (5 billion kg) of carbon dioxide from the atmosphere, the equivalent of removing nearly 2.25 million cars from the road for one year.
Misleading claims and biased assumptions. Benbrook makes assumptions relating to herbicide use on U.S. crops that are inconsistent with actual (or recommended) practice. He overestimates herbicide use on some genetically engineered, herbicide-tolerant crops in the United States while significantly underestimating herbicide use on conventional (non-genetically engineered) crops.
Attempting to lend verisimilitude to his analysis, Benbrook states repeatedly that his analysis is based on official, government (USDA) pesticide usage data. While he did use a USDA dataset, its limitations required Benbrook to rely on his interpretations of herbicide application, which as discussed above, are inaccurate. Therefore he cannot reasonably claim that his analysis carries any governmental imprimatur.
Lack of critical context for data. Benbrook reports a 19% increase in the amount of herbicide used on three major U.S. crops (soy, corn, and cotton), but he neglects to mention the critical fact that American farmers also significantly increased their acreage – by 14% — during the period in question. Thus, even if per acre herbicide use had remained constant, the addition of new acreage alone would account for three-quarters of his claimed increase in herbicide application. But as discussed above, herbicide usage per se is not a valid surrogate for damage to human health or the environment, so Benbrook’s preoccupation with it is a red herring.
Ignorance of the relevant scientific literature. In the press release for his article, Benbrook claimed that his was the first peer-reviewed paper to examine changes in pesticide use due to the cultivation of genetically engineered crops in the United States. In fact, there have been numerous analyses by other researchers that have examined this issue in peer reviewed papers, a fact apparently missed by both Benbrook and the peer-reviewers of his manuscript. Graham Brookes, one of the authors of this article, for example, has written nine peer reviewed papers — all of which pre-date Benbrook’s article — on the impact of genetically engineered crops on pesticide use.
In summary, as a case study, Benbrook’s paper is typical of a genre: anti-technology fiction. Although pretending to be the product of serious scholarship, it is just another in a series of ideologically driven, anti-technology articles by this author and a handful of others who use flawed methodology and sophistry to arrive at a preordained but fallacious conclusion. Based largely on inaccurate and misleading material and the distortion of data, these fabrications are then widely promulgated and cited by anti-technology NGOs as part of their concerted efforts to disparage products and processes they dislike.
Graham Brookes is an agricultural economist with the UK-based consultancy business PG Economics and author of 13 peer reviewed papers on the economic and environmental impact of genetically engineered crops. Henry I. Miller, a physician and molecular biologist, is the Robert Wesson Fellow in Scientific Philosophy and Public Policy at Stanford University’s Hoover Institution and a fellow at the Competitive Enterprise Institute. He was the founding director of the Office of Biotechnology at the FDA.
Genetically Modified Food (Photo credit: Peter Blanchard)