The Science of GM Crops: A New, Fair Report


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Few topics in the food world are debated as contentiously as genetically engineered (GE) crops. Advocates hyperbolically charge that GE seeds will feed the world through increased crop yields, save the environment by eliminating pesticides, and make poor farmers rich. Detractors, deeming these seeds the diabolical feedstock for "frankenfoods," argue that they'll destroy biodiversity, afflict us with allergies, drive poor farmers to suicide, and foster "superweeds" that'll choke out native flora and fauna. What's often missing in all the drama is neutral scientific support.

That's starting to change. Last week the National Research Council (NRC) released the most extensive (and unbiased) report to date on the performance of GE crops since their commercial introduction in 1996. The report was quite explicit about the threat of herbicide resistance caused by over-spraying GE crops with broad-spectrum herbicides (more on this soon). At the same time, it provided several reasons to be optimistic about the responsible use of GE crops, both now and in the future.

Even GE's most ardent detractors should give due consideration to the following sample of findings:

1. Farmers globally have applied less insecticide per acre as they've increased their use of Bt seed (seed engineered for insect resistance). Beyond the obvious health benefits, reduction in insecticide application has saved substantial aviation fuel, water (to make insecticides), and plastic containers.

2. Farmers and their families have been safer from chemical exposure as a result of less harsh pesticides and less time spent out in the fields spraying. The authors of the report hypothesize that farmers pay more for GE seeds in part to protect their families and employees from exposure to harsh chemicals.

3. The greatest environmental benefit of adopting GE crops may turn out to be the rate at which water is retained as a result of conservation tillage, which herbicide tolerant (HT) crops directly foster. No-till methods also improve soil health, something conventional farming is often accused of ignoring.

4. Economically, the savings gained from GE adoption generally outweighed the expense, and the economic benefits gained by adopting farmers also extend to non-adopters as well. In controlling so effectively for the corn borer, for example, Bt corn indirectly protects neighboring crops. (A very similar thing happened in Hawaii when GE papaya was introduced to save the crop from a devastating outbreak of ringspot in the 1990s.)

5. The drift of pollen from GE to non-GE plants—a phenomenon that anti-GE advocates often highlight as a chronic problem—turns out to be relatively rare, or at least "not a concern for most non-GE crops." This is not to say that it doesn't happen, or that it doesn't matter, but only that drift is hardly a first-order concern when it comes to GE pollen.

For all the report's enthusiasm for the potential benefits of GE crops, it was by no means shilling for the technology, much less the corporations that monopolize it. As mentioned earlier, of particular concern to the study's researchers was the repeated and exclusive use of glyphosate herbicides (the most common of which is Monsanto's Roundup Ready). As scientists have long predicted, the spraying of a single agent can quickly lead to glysophate resistance in the targeted weeds, thus forcing farmers to spray even more toxic chemicals in order to control them.

Appropriately, the NRC dedicated ample space to offering advice that could mitigate the impact of this dangerous (albeit predictable) development that could negate the environmental gains associated with herbicide-resistant crops. The organization advises farmers to employ a rotation of different herbicides as well as "tank mixes" that combine several agents into a single concoction. It also notes that GE seeds are now being developed that will make alternative weed management strategies more readily adoptable. It did not mention, but might have, the fact that weed resistance remains a major problem with traditionally bred seeds as well. Some evidence suggests that the problem may be worse with conventional seeds.

In highlighting both the strengths and weaknesses of GE crops, the NRC report does this rancorous debate a great service—it suggests room for compromise. Of all the suggestions that the report offers, there one in particular that might provide a foundation upon which detractors and advocates could find common ground: "Genetic engineering could potentially be used in more crops, in novel ways beyond herbicide and insect resistance, and for greater diversity of purposes."

Implicit in this comment is the critical recognition that current applications of GE technology—mainly soy, corn and cotton—ultimately perpetuate monoculture systems that churn out food and fiber destined for feedlots, ethanol plants, junk food, and factories. In other words, the technology—despite its environmental benefits—is still a technology that greases the wheels of industrial agriculture.

But biotechnology can do better than that. Right now a range of more humanitarian, environmentally sound GE seeds wait in the wings. These seeds—bred for a wider variety of traits (such as drought resistance), for a diversity of subsistence crops (cassava, millet, rice), and to serve niche producers in local markets—have (as I will discuss in a future post) been stymied by growing public distrust of GE seeds in general. As with most agricultural subjects, however, distinctions must be drawn. The NRC report guides us in doing just that.