If I get into a disagreement about an evidence-based topic with friends, it often centers on two subjects. If the friend is left of center, the disagreement is about GMOs (or sometimes alternative medicine). If right of center, the conflict is climate change. On both topics, I do my best to follow consensus science instead of ideology or gut feelings.
I’m not a food safety specialist; and I’m not an atmospheric scientist, so I go with the experts in those fields. Science is messy and there are always conflicting results. But science also works its way to reliable answers over time. When there are decades of research, as with these topics, it not too hard to find a real signal in all the noise.
For genetically engineered plants (and to a smaller extent, some issues about glyphosate), I’m taking some claims one by one, and, as I said, doing my best to discern expert opinion.
Claims about GEs causing damage
Food from GE plants harm the people or animals that eat them. The current scientific consensus is that GE foods are safe to eat. I have read material by anti-GE groups denying this consensus and listing the research showing negative effects. Some of those negative studies were badly designed (Seralini, Leblanc), but good or bad design aside, the evidence for safety is pretty overwhelming. There have been more than 3,000 studies of GE food safety over 25 years, much of it by independent non-industry groups. The overall case is so clear that the following organizations have examined the evidence and said GE food is safe:
- US National Academies of Sciences
- The American Association for the Advancement of Science
- The European Commission
- The National Academy of Sciences
- The World Health Organization
- The Royal Society of Medicine (UK)
- Food Standards, Australia and New Zealand
- The French Academy of Science
- The Union of German Academics and Sciences and Humanities
This list goes on – there are many, many more groups (botany, toxicology, phytopathology) that could be mentioned. However, to some anti-GE people, every one of these scientific organizations spanning the globe has got the science wrong, or else they’ve been bamboozled or bribed – amounting to a worldwide conspiracy encompassing thousands of scientists and hundreds of organizations. This is an actual argument I get from climate change denialists — just swap GE science with climate science and it reads the same.
GE crops use more insecticide than other crops. False. The plants bred to resist pests use less. That’s one of the reasons farmers choose them. (GEs are also associated with smaller carbon emissions.) https://www.tandfonline.com/doi/full/10.1080/21645698.2018.1476792 See the next entry for more confirmation of less pesticide.
GE crops use more herbicide. Sometimes true. According the following study, GEs use less pesticide, but GE soybeans (Roundup Ready) use more herbicide now because some weeds are growing resistant to glyphosate. https://phys.org/news/2016-09-largest-ever-reveals-environmental-impact-genetically.html The resistance problem occurs with any herbicide used regularly. That’s why farmers should vary their methods and rotate their crops. GEs are just one item in a farmer’s toolbox. There are some plants that are “naturally” bred for herbicide resistance, rather than engineered, and they can have the same issue. Note: weeds that grow resistant to an herbicide are not science fiction super weeds that will conquer the earth – they are just resistant to an herbicide.
GEs don’t have a higher yield. False. This is another reason farmers choose GEs – higher yields. Here’s a meta-analysis of 21 years worth of data showing higher yields with corn. https://www.nature.com/articles/s41598-018-21284-2 And another meta-analysis of 147 studies shows a 37% decrease in pesticide use and 22% increase in crop yields (and 68% increase in profits). http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0111629. Again, you can find studies that show otherwise, but the evidence in the other direction, as well as the fact that farmers choose them, is much more substantial.
Farmer suicides in India. The introduction of GE crops in India has been blamed for economic damage resulting in as many as 17,000+ farmer suicides in a single year in India. This is a science issue insofar that it directly contradicts data you can easily look up. There were 16,000+ farmer suicides happening annually in India before GEs were even introduced there in 2002, so how does this correlation even make sense? It’s a myth, and a pretty outrageous one at that. https://timesofindia.indiatimes.com/india/NDA-UPA-failed-to-curb-farmer-suicides/articleshow/39501676.cms
Putting a patent on seeds is bad or immoral and so is having to buy them each year. This is less about science and more about hypocrisy. Many of the seeds that farmers use in the U.S. are patented hybrid seeds that are purchased new each year (we’re talking about non-GE seeds.) It has been this way for decades. So why is this being framed as a GE issue? Why aren’t people denouncing patented hybrids? By the way, patents expire eventually. The patent for first-generation Roundup Ready soybean seeds expired in 2015 and some farmers are now using generic GE seeds. https://www.technologyreview.com/s/539746/as-patents-expire-farmers-plant-generic-gmos/ It’s worth noting here, by the way, that farmers are not helpless dupes who are forced or conned into buying a particular type of seed.
GEs use more water. False. GE plants bred for drought tolerance certainly use less. As for other GEs, I’ve seen a single study out of Brazil claiming that one plant – GE soybean – needs more water. Much more evidence is needed before we should believe this.
Because some GE plants are made to be used with glyphosate, it’s worth taking a quick look at the question of its toxicity.
The IARC (International Agency for Research on Cancer), part of the World Health Organization, declared glyphosate to be “probably carcinogenic.”
- The IARC did not look at the results of the largest and best study ever done on glyphosate and cancer (50,000 famers and their families). This study showed no correlation between glyphosate and cancer. https://www.reuters.com/article/us-health-cancer-glyphosate/large-u-s-farm-study-finds-no-cancer-link-to-monsanto-weedkiller-idUSKBN1D916C
- The man in charge of the IARC investigation said that the inclusion of this data would have altered the IARC declaration, making the cancer declaration less likely. https://www.reuters.com/investigates/special-report/glyphosate-cancer-data/
- Every other scientific panel that examined the evidence concluded there is no correlation between glyphosate and cancer. That includes the EPA, Health Canada, the European Food Safety Authority, the German BfR (Federal Institute for Risk Assessment), the Food and Agriculture Organization of the U.N., the WHO Core Assessment Group, the WHO International Program on Chemical Safety, and more. It’s a pretty high bar to prove them all wrong.
Personally, I’m not inclined the think that any herbicide is going to be harmless, but the cancer claims seem overblown given the weight of evidence against it. There was recently a jury trial that awarded a man who blamed Roundup for his cancer. His lawyers, no doubt aware of the consensus around glyphosate safety, claimed that it must have been a combination of glyphosate and other ingredients in Roundup that caused the harm. There is not solid evidence to back this up, though maybe more research will show a relationship. It’s worth noting that if Roundup is ever pulled from the market, farmers will likely turn to more toxic chemicals.
No, it’s not true that the FDA, the EPA, and Monsanto/Bayer have schemed together to suppress data about alarming amounts of glyphosate in the food supply. https://www.snopes.com/fact-check/monsanto-suppressing-evidence-of-cancerous-herbicide-in-food/
That’s it for my aside about this chemical. Herbicides are poison, so minimize exposure. At the levels that get into the average person’s body, glyphosate is one of the least nasty. Now back to GEs.
Let’s Sum it Up
Say what you will about bad businesses practices of big agriculture and I might well agree with you. For example, I dislike the consolidation of any industry into a handful of mega-corporations. But regarding inherent dangers of GE foods, I will go with expert opinion. You can point to studies that show danger, you can quote scientists who have doubts, but I need the long list of scientific organizations near the top of this post to change their minds. If that happens, I’ll be right there with you. The same goes for insecticide use and yields – when you’ve overturned all the meta-analyses of studies and changed the minds of the preponderance of independent researchers, I’ll be with you there, too.
As noted above, there is an issue with herbicide resistant weeds with some of the glyphosate-ready plants. No surprise. If it becomes a problem, farmers can use other seeds or change-up their methods as desired. Note that this just one particular use of GEs.
Meanwhile, I see anti-GE groups trying to shut down non-profit, open source projects like GE Golden Rice to fight Vitamin A deficiency in third-world countries, and the attempt to save the American Chestnut tree with a blight-resistant variety. The emotional, relatively fact-free arguments against them only do harm. Here’s a good summary from 2015 about the disingenuous and sometimes fraudulent campaigns against GEs: http://www.slate.com/articles/health_and_science/science/2015/07/are_gmos_safe_yes_the_case_against_them_is_full_of_fraud_lies_and_errors.html
Long post. If you read this far, I salute you.