Skip to content
Home » Do GMO crops have a higher yield? It depends on the answer.

Do GMO crops have a higher yield? It depends on the answer.

gmo-corn-rxThe Union of Concerned Scientists (UCS) is an American environmental organization founded in 1969 at the Massachusetts Institute of Technology, which claims 400,000 members. They focus, generally, on environmental issues like nuclear power, global warming and a few other issues. Many of these issues are critically important, and a science advocacy group like UCS helps keep the scientific facts about global warming and other environmental issues at the forefront of the discussion.

But one area where UCS has gone off the rails of scientific evidence and embraces generally left wing science denialism is agriculture, more specifically GMO, or genetically modified organisms (or in this case crops). They are generally supportive of organic farming (which has little or no health benefit at a high cost to consumers) and vehemently opposed to GMO crops, based on what appears to be the same bad scientific critical skills that we observe in global warming deniers. There is nothing more frustrating than dogmatic science that stands against evidence. 

There are few, convincing, peer-reviewed studies that show any risk from consuming GMO foods. Late last year, an article was published by Séralini et al. that seem to show that a particular GM corn, made by Monsanto, would cause cancer. The anti-GMO world was so desperate to grab onto any evidence that would support their beliefs about the evil of GMO crops that they broadcast this study widely. The dean of pseudoscience, Dr. Oz, hyped the study to his fawning and uncritical audience. Except the study was thoroughly debunked by a vast range of scientists, most of whom had little general interest in agriculture, but saw bad science for what it is: bad science.

A lot of the controversy about GMO’s seems to be based on the the precautionary principle, which states that if an action or policy has a suspected risk of causing harm to the public or to the environment, in the absence of scientific consensus that the action or policy is harmful, the burden of proof that it is not harmful falls on those taking an act. Yet, there are literally dozens of peer-reviewed articles that show that GMO crops are safe. And the scientific consensus also concludes that GMO’s are safe. Once again, individuals conflate a political debate or opinion with scientific evidence. Other than a small group of scientists, most of them associated with UCS and other left-leaning environment groups, there just isn’t a controversy with regards to GMO crops. Just switch sides of the political aisle, and it’s the same thing with global warming or evolution–the only debate is a political one where right-wing science deniers are insisting that the vast mounds of scientific evidence are wrong.

It’s also clear that anti-GMO feelings arise, partially, from the Appeal to Nature logical fallacy, that is, natural is better, even without any evidence supporting that belief (see my comments above about organic farming). What is amusing is that the natural, genetically unmodified corn, called teosintes, looks like your typical lawn grass. The fruiting body, the ear of corn that we all eat, is tiny. Corn was domesticated 10,000 years ago through, unsurprisingly, genetic modification. Our distant relatives were amazingly adept at genetic manipulation, and central Americans were able to domesticate corn. So the “natural” corn exists only as a wild plant in parts of Mexico. What we eat is completely different thanks to genetic modification, whether its grown in a huge agribusiness farm or in your small domestic cornfield in your backyard.

Moving beyond the fears of potential health danger of GM foods, what are the benefits? Probably the only reason to plant GMO crops is to vastly increase yields of food. This yield may be increased by reducing damage from pests, increasing drought resistance, or improving the amount of food from each plant. If there were no benefits from GM crops, then maybe the precautionary principle makes sense. 

Of course, the UCS has a point of view on this matter. They published a white paper (a non-peer-reviewed document that tries to look like a real scientific paper) that concluded that “overall U.S. corn yields over the last several decades have annually averaged an increase of approximately one percent, which is considerably more than what Bt (a type of GMO corn) traits have provided.” In other words, based on this one type of GMO corn, UCS is claiming that the corn doesn’t have a higher yield than conventional corn (whatever that may be).

But the UCS is using a term called “intrinsic yield” which means something very specific in agricultural, and does not mean what many of us think is meant by “yield.” The UCS claims that GMO plants (in this case corn) do not appear to produce higher “intrinsic yields”; but what they mean is that the GMO crops don’t produce more kernels per cob. But “yield” to a farmer means something more. It’s the total amount of corn (or other crop) that they can produce at fixed costs (land, water, pesticides, whatever) in a fixed area. For example, if more corn survives to maturity because it is more resistant to pests and requires less pesticide (or other non-“natural” compounds), the the yield of the farmer’s field is higher, even if each individual plant does not produce more.

A recently published communication in Nature Biotechnology shows that GMO corn sometimes has higher and sometimes lower yields than conventionally bred corn, if you ignore all confounding factors in the environment. In years where GM corn was producing similar or lower yields than conventionally bred corn, the environmental factors, such as weather, disease or pests, were average. When accounting for the bad environmental situations, GM corn had significantly greater yields. 

In other words, semantics matter. Using the UCS definition of “yield”, which just looks at a single plant and ignores all other factors, GMO corn has no advantage. But in the real world of agriculture, the yield can be larger, sometimes quite a bit larger, under real world conditions that include a whole host of environmental challenges for the plant.

The point is that the value of GMO crops should not be underestimated, and the semantics can change how we value these crops. A real skeptic looks at the evidence for the value of the GMO crops (seems positive) while examining the evidence for the health risks (there is just nothing out there that scientifically supports any health issues with GM crops)–the scientific conclusion remains the same that GMO crops have a large positive benefit to mankind.

I know that a lot of hatred of GMO crops is pointed at Monsanto, which is one of the larger marketers of GM crops. But since many of the comments about Monsanto are strawman arguments or are intentionally poisoning the well, logical fallacies that are laughably similar to the arguments made about Big Pharma and vaccines, it’s hard to accept them. There are some arguments about GM crops that have some validity. Biodiversity is one that is concerning, but that can be overcome with small, sustainable farms that are willing to produce genetically diverse crops, which will attract a higher price from consumers who want them. But in a crowded world with less and less fertile farmland, it is important that “yields” be increased, and that may always require genetic manipulation–something that was done 10,000 years ago to get us the first domesticated corn.


Key citations:

Michael Simpson

Don’t miss each new article!

We don’t spam! Read our privacy policy for more info.

Liked it? Take a second to support Michael Simpson on Patreon!
Become a patron at Patreon!