How GMO Crops Can Be Good for the Environment

Photograph by Noah Berger/Bloomberg

Among the winners in this month’s elections, along with the Republican candidate in just about every competitive race, were foods containing genetically modified organisms. Ballot initiatives that would have mandated the labeling of GMOs on store shelves lost in both in Colorado (overwhelmingly) and Oregon (narrowly). Nobody knows exactly how the passage of those measures would have affected the sales of GMO products over the long run; consumers have shown a tendency to ignore the calorie counts on food labels.

Still, it’s possible that over the short term labeling laws would make foods containing GMOs less popular and therefore decrease the amount of farmland, in the U.S. and abroad, given over to modified crops. That was the goal of many labeling proponents, and a new study suggests it would have been a bad result.

The study doesn’t look at the health effects of GMOs. Thousands of independent studies have already done so and found that GMOs are perfectly safe to eat. The new research instead looks at the costs and benefits for agriculture and the environment, a question on which there is less consensus. Plenty of research, including this large study from the National Academy of Sciences, has found that GMOs have significantly increased farm yields while decreasing pesticide use and soil erosion. The idea is that because GM crops are engineered to produce insecticides in their tissues or to be immune to particular herbicides, they reduce the man-hours, fuel, and chemical inputs in farming, even while reducing losses to pests and weather. (Anti-GMO groups have looked at the same data and argued that the yield gains are minimal (PDF) and limited to special circumstances.)

The new study, in the journal PLOS One, comes down strongly on the pro-GMO side. It’s a meta-analysis that aggregates and examines the results of 147 existing research studies looking at GM soybeans, maize and cotton, the world’s biggest GM commodity crops. The authors, a pair of agricultural economists at Germany’s University of Göttingen, found that GM technology increased crop yields by 22 percent, reduced pesticide use by 37 percent, and increased farmer profits by 68 percent.

A few details jump out from the study. For one, the benefits were greater in those GM crops that produced their own pesticides rather than those engineered for herbicide resistance—the latter trait has been hugely convenient for farmers, but has also shown a greater rebound effect as weed species evolved resistance to the chosen herbicides.

The yield and profit gains were also greater in developing countries than in developed countries. Finally, the studies in the meta-analyses that were published in peer-reviewed journals showed more dramatic effects, both in yield and profit gains, than those published elsewhere. Put another way, the more rigorously vetted a study, the more likely it has been to find benefits for GMOs.

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