Genetically modified organisms: Let science prevail, not rhetoric

In my recent article, Strong GMO opponents unmoved by facts, I cited Biowatch South Africa as an example of anti-GMO activism. Vanessa Black, its advocacy, research and policy coordinator, felt compelled to pen a vehement rebuttal. Of course, it cannot go unanswered, or people might get the wrong impression about who is right.

I am, she says, “a prisoner of [the] genetic industry’s ‘facts’ ”. How exactly my freedom to reach conclusions based on the published academic literature renders me “a prisoner”, escapes me. So does the reason the word “facts” needs quotation marks, as if they are not really facts at all.

According to Black, I “mainly [cite] scientists who are paid for and backed by powerful GMO interests”. In support of this claim, she points to the study I referenced about the positive impacts of genetically modified (GM) crops in Spain and Portugal.

There is no reason to believe that the study reaches false conclusions, and Black does not make the case that it does. Instead of challenging its substance, Black argues that the author is a director of a consultancy which has clients in the agritech industry. This may well be true; it would be extraordinary for an independent researcher not to have industry clients. That does not mean he is wrong. She also says that the study was funded by a pro-GMO lobby group, but provides no evidence for this claim. If true, it would also not invalidate its conclusions.

But let’s suppose these findings are invalid. Being new, the study was merely the hook on which I hung the story. It was the latest in a growing mountain of papers with similar findings. The other papers to which I refer were reviews of the existing literature, published by independent academics and covering thousands of peer-reviewed studies.

In 2013, an overview of 10 years of GM crop safety research published in Critical Reviews in Biotechnology examined 3,668 papers and concluded: “The scientific research conducted so far has not detected any significant hazards directly connected with the use of GE crops.”

In 2018, a meta-analysis of 21 years of field data published in the prestigious journal Nature examined 6,006 papers and concluded that there were clear benefits in terms of increases in grain yield and quality, decreases of target insects without effect on the abundance of non-target insects, and a significant reduction of mycotoxin in grain, which is toxic to humans.

These studies, and indeed all my other sources, had no links to the GMO industry whatsoever, but they all supported the claim of significant benefits and minimal risk.

It is inevitable, and indeed desirable, that industry research is published in the peer-reviewed literature. However, half of all the research on GMOs is independent. Having challenged the industry research not for being wrong, but merely for being conducted by the industry, Black will then have to explain why the vast majority of the independent research comes to exactly the same conclusions regarding GMO benefits and safety.

I noted the opinions of 280 scientific and technical institutions around the world, including major national academies and national health authorities, all of which are independent of the GMO industry, and all of which support the safety of GMOs.

Contrary to Black’s claim, I did not “mainly [cite] scientists who are paid for and backed by powerful GMO interests”. I mainly cited those that were not. I cited only one that she, fallaciously, considers tainted and this forms the entire basis of her false generalisation. Because she won’t accept one of the papers I cited, she calls all of it “fake science”. And then she accuses me of “selectivity”.

Her other point challenged my claim that glyphosate, a modern herbicide against which some GM crops are resistant, is not dangerous. She says that I cited one of my own columns, which I did merely so I wouldn’t have to repeat the arguments I made there. Yet she promptly describes the World Health Organisation’s International Agency for Research on Cancer (IARC) as “credible, independent and usually cautious”. This shows that she didn’t bother to read that article at all.

The IARC does not evaluate cancer risk. It evaluates the strength of the evidence that a substance is hazardous. Hazard is not the same thing as risk. I’ll quote the IARC itself on the difference:

“A cancer hazard is an agent that is capable of causing cancer, whereas a cancer risk is an estimate of the probability that cancer will occur given some level of exposure to a cancer hazard… The [IARC classifications] identify cancer hazards even when risks appear to be low in some exposure scenarios.”

So the IARC says nothing about how dangerous a substance is. It is entirely useless in making safety claims about substances.

The last time I wrote about the IARC, I noted that out of the more than 1,000 substances it evaluated, it had only ever classified a single substance, caprolactam, as “probably not carcinogenic to humans”. I then said that this was a mistake because one cannot prove a negative, and the absence of evidence of carcinogeneity does not prove non-carcinogeneity. I’m delighted to discover that in 2019, the IARC corrected its mistake and reclassified caprolactam to be “possibly carcinogenic”. It has now never found a substance not to be carcinogenic.

Now, the IARC classifies glyphosate as “probably carcinogenic in humans”. That is the classification below “carcinogenic to humans”, which is the only category for which sufficient evidence of actual carcinogeneity in humans is required. In the specific case of glyphosate, the IARC found “limited evidence” that it can cause (not does cause) cancer in humans.

This classification places glyphosate on a par with frying, being a barber or hairdresser, consuming red meat, and drinking very hot beverages. It’s not so terrifying, in other words, provided you take reasonable precautions to limit your exposure.

For information on whether it does cause cancer in humans, we cannot use the IARC classification. Let’s instead turn to the US Environmental Protection Agency’s 2017 evaluation of glyphosate’s carcinogenic potential. It includes a brief history of findings about the carcinogeneity of glyphosate (on p.12ff), which acknowledges the IARC classification as the sole recent adverse finding. Having considered 63 epidemiological studies, 14 animal carcinogenicity studies and nearly 90 genotoxicity studies for glyphosate, it concludes (on p.144) that glyphosate is “not likely to be carcinogenic to humans”.

Besides causing cancer, a substance can, of course, simply be toxic. It would not be at all surprising if a herbicide turns out to be toxic, even if it is much less toxic than older-generation alternatives on the market.

The dose at which glyphosate is lethal to 50% of experimental rats (LD50) is 5.6 grams per kilogram of body weight, provided it is consumed orally. A material safety data sheet for a popular glyphosate-based herbicide confirms this.

Of course, you could make your own “natural” weed killer. Here’s a recipe, in Murica freedom units: one gallon of white vinegar, one cup of salt and a tablespoon of liquid dish soap. The dish soap consists of multiple chemicals, the most toxic of which has an LD50 of 1.3g/kg body weight in rats. Vinegar has an LD50 of 3.3g/kg. And table salt has an LD50 of 3g/kg. So every individual ingredient of your “natural” concoction is more toxic than glyphosate.

Or you could be an organic farmer, and use copper sulphate as a pesticide. Its LD50 in rats is 0.5g/kg, making it more than 10 times as toxic as glyphosate.

Black makes much of a few court cases against agritech companies. But courts are not scientific institutions and juries are not scientists. Tort lawyers make billions convincing lay juries to make damage awards against companies with deep pockets, and they win not when they prove their case beyond a reasonable doubt, but when those non-experts on the jury believe there to be better-than-even odds that the respondent is at fault. Forgive me for citing actual science, instead.

Unlike my income, which is entirely independent of industry or activists, Black’s salary, and the revenue of the lobby group for which she works, are dependent on maintaining the fiction that GMOs are harmful and that agritech businesses are dangerous, so I do not expect her to concede her errors.

I’ll bow out with a video of a guy drinking a cocktail of glyphosate and fracking fluid. How’s that for “fake science”, Biowatch? DM