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National Academy of Sciences Finds Genetically Engineered Crops Not the Solution to World Hunger

By Bill Freese, Science Policy Analyst and Doug Gurian-Sherman, Director of Sustainable Agriculture and Senior Scientist

May 23, 2016
Center for Food Safety

New Report Downplays Harms of Herbicide-Resistant GE Crops

A new report released this week by The National Academy of Science (NAS) – Genetically Engineered Crops: Experiences and Prospects – provides some useful perspectives on the contentious debate surrounding genetically engineered (GE) crops, and is particularly noteworthy for calling into question the frequent claim that GE crops are key to “feeding the world.” But in other respects it is shallow and disappointing due to the lack of holistic analysis and frequent bias in favor of GE crops and herbicides whose use they promote.

The committee that produced the report devoted considerable space to assessing the yield implications of current genetically engineered crops, which were developed to survive treatment with herbicides and/or provide resistance to certain insect pests. Overall, the NAS committee found a steady increase in U.S. crop yields that spans both the pre-biotech and biotech eras. This strongly implies that other factors, such as advances in conventional breeding methods, have played a critical role in raising crop productivity. By contrast, they found no evidence that GE traits provided measureable increases in overall crop productivity.

Significantly, the report did not find clear benefits from GE crops in developing countries for small, impoverished farms. This finding is consistent with the observation that one billion people remain food insecure, despite massive adoption of GE crops globally on over 400 million acres. 

While not part of its charge, the committee went out of its way to emphasize the critical importance of agroecological farming (farming based on the science of ecology and relying on natural processes and biological and cultural diversity) and conventional breeding systems to alleviate hunger and malnutrition. The committee also noted that the public investment in agricultural research needed to promote these non-biotech approaches is stagnating or declining. In fact, agroecological approaches receive only a tiny portion of the U.S. agricultural research budget. The budget instead remains devoted largely to advancing the industrial agriculture that genetic engineering has been part of.

The NAS committee’s assessment of herbicide-resistant GE crops provides some relevant analysis, for instance that these crops have increased overall herbicide use. NAS also refutes the popular myth that herbicide-resistant crops advance soil conservation, showing instead that U.S. federal farm policy introduced in 1985, a decade before GE crops, is largely responsible for promoting farmer adoption of soil-conserving techniques such as no-till. NAS could also have explained that herbicide-resistant weeds generated by cultivation of GE crops are leading to greater use of soil-eroding tillage, and that soil erosion rates have leveled out at alarmingly high, unsustainable levels over the GE crop era.

Otherwise the treatment of herbicide-resistant GE crops is cursory and deficient. This is particularly unfortunate given the predominance of this GE crop type in world agriculture.  Amid a confusing plethora of figures on GE crop prevalence in various countries, we found no reference to the simple fact that an astounding 84% of the world’s GE crops (by acreage) express herbicide resistance traits. There is essentially no discussion of how these crops have triggered extremely rapid evolution of herbicide-resistant weeds on over 60 million acres of U.S. cropland alone, as well as overseas. Despite citing a paper on the subject, the committee shows no appreciation of the “transgenic treadmill” phenomenon whereby today’s herbicide-resistant weeds become the pretext for introducing crops immune to multiple weed-killers – a classic “technofix” that will only spur a spiral of increasing weed resistance and herbicide use. 

The committee did not explore how the initial labor-saving effect of herbicide-resistant GE crops has contributed to increased farm size, as larger growers expand at the expense of smaller ones, despite citing a USDA report that addresses this very subject. The committee fails to discuss how the seductive convenience of GE crop weed control hinders progress toward sustainable, non-chemical weed management techniques – a fact (once again) that even USDA concedes. 

We saw no discussion of how the biotechnology industry’s structure as combined pesticide-seed companies has led these firms to prioritize development of herbicide-resistant crops, which generate additional sales of weed-killing pesticides the companies also sell. Nor does the committee address how this profit-seeking R&D focus on herbicide-resistant crops helps explain the industry’s virtual failure to develop much-touted GE crops with other types of traits (beyond insect-resistance). This failing is particularly relevant to one of the committee’s primary charges – to assess the future prospects of GE technology. These latter points exemplify a systemic failure of the report to address the scientific literature on GE crops in the broader context of the biotechnology industry’s development priorities, as well as its often unethical PR and marketing practices.

NAS’s assessment of the human health and environmental effects of glyphosate herbicide is flawed by outright errors and bias. On the environmental side, there is no serious doubt that the massive, GE crop-driven increase in glyphosate use has been a prime driver of monarch decline by decimating milkweed, the monarch’s host plant, in Midwestern cropland.[1]  NAS questions this consensus view of credible monarch scientists and the U.S. government, which is sponsoring efforts to restore milkweed to benefit monarchs.  NAS also entirely fails to mention that the monarch’s situation is so dire that the U.S. Fish and Wildlife Service is seriously considering a petition to list the monarch as a threatened species under the Endangered Species Act. 

NAS concedes that the World Health Organization’s International Agency for Research on Cancer (IARC) last year found glyphosate to be “probably carcinogenic to humans,”[2] and also correctly notes that EPA regarded glyphosate as possibly carcinogenic in the 1980s.  What the committee fails to explain is that EPA’s about-face on glyphosate came after intervention by the herbicide’s manufacturer, Monsanto.  NAS also appears unaware that IARC’s determination that glyphosate is probably carcinogenic represents the majority view of the medical science community, which is opposed mainly by Monsanto and the U.S. and European regulators under its sway.

On the subject of food safety, NAS helpfully recommends greater use of sophisticated “-omics” techniques to improve assessment of GE crops for potential unintended health effects; but fails to draw the obvious conclusion that GE crops approved without use of such techniques (as well as long-term animal feeding trials) have not been reasonably demonstrated to be safe.  However, the committee does provide a decent analysis of the food allergy risks posed by GE crops. 

Despite acknowledgement of potential health threats, NAS fails to endorse the sensible recommendation of a 2002 NAS committee that all GE crops be subject to regulatory assessment, while providing no workable product-based strategy that would ensure all potentially harmful GE crops are assessed for safety.  This regulatory issue is becoming increasingly critical as more and more GE crops escape any regulation at all under the current flawed U.S. system.

Overall, the NAS committee has provided some relevant analysis of GE crops.  The report makes clear that alleviating hunger and malnutrition will require reinvigoration of public sector agricultural research and greater deployment of conventional breeding and agroecological techniques guided by the needs of the poor rather than the profit motives of biotechnology companies.  But in most other respects the report is flawed by a disappointing failure to provide a holistic analysis of the real world impacts of most currently grown GE crops.


[1] NAS even misinterprets a key study (Hartzler 2010) as showing a 90% (rather than the actual >96%) decline in milkweed prevalence in Iowa cropland from 1999 to 2009.
[2] The committee incorrectly states that IARC formerly classified glyphosate as merely “possibly carcinogenic” (Group 2B) when in fact IARC’s 2015 determination that glyphosate is “probably carcinogenic to humans” (Group 2A) represents its first assessment of the herbicide.

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