Anti-pesticide activist Carey Gillam recently moderated a panel discussion about the weed killer glyphosate. I attended and took notes. Here's what I saw.
One of the best ways to sustain your bad ideas is to surround yourself with people who think just as you do. Like a cult member who only associates with other true believers, you're effectively cut off from outside scrutiny. The economist Thomas Sowell put it this way in Intellectuals and Society:
When the only external validation for an individual is what other individuals believe, everything depends on who those other individuals are. If they are simply people who are like-minded in general, then the consensus of the group about a new idea depends on what the group already believes in general—and says nothing about the empirical validity of that idea in the external world (p 7).
This phenomenon was on full display during a July 19 webinar titled “Context and Convergence: A Dialogue on Glyphosate, Human and Planetary Health.” Hosted by Farmer's Footprint, the event featured an all-star lineup of anti-pesticide rabble-rousers—including US Senator Cory Booker, Dr. Zach Bush, Kelly Ryerson (the self- described "Glyphosate Girl"), and organic-industry lobbyist Carey Gillam.  The discussion also included political economist Calla Rose Ostrander and Matt Nicoletti, head of business development at Penny Newman Grain Company.
Noticeably absent from the panel was anybody with expertise on the chemical under discussion. A toxicologist, chemist, epidemiologist, soil scientist, or farmer who understands how glyphosate works would have pushed the discussion in a productive direction. Instead, thousands of attendees, myself included, were treated to six yes-men nodding in agreement for two hours.
Since no dissenter was invited to participate and the panelists took no questions, here's a day-after review of the clown show.
The conspiracy that isn't
Gillam, Bush and Ryerson established two conclusions early on. They first asserted that glyphosate exposure has driven increases in serious diseases, and, second, that chemical companies and regulators have suppressed research that vindicates this conclusion. Both claims are patently false. You can easily find many studies that link glyphosate exposure to all sorts of maladies. The problem isn't that these papers have been suppressed by "Big Ag," the problem is that they're generally awful.
Feeding lab rats mass quantities of a pesticide (far greater amounts than humans are exposed to) doesn't yield clinically useful information. The same goes for experiments during which immortalized cell lines are bathed in glyphosate.  There are actually several such studies that suggest the herbicide has cancer-fighting properties. These aren't proof positive that glyphosate destroys tumors; they just illustrate the range of truly odd results you can generate with cell-culture experiments.
Bush claimed that he's done 10 years worth of this research. Cell biologist Dr. Mary Mangan, who knows this topic backwards and forwards, was unable to locate any of Bush's published studies. But let's assume for the sake of argument that the good doctor's work has found its way into peer-reviewed journals. In contrast to Bush's outlying results are thousands of better-designed studies that have failed to link chronic glyphosate exposure to any health risks. The panelists didn't address this imbalance of evidence, nor did they explain how all those contrarian papers were published despite the agrochemical industry's conspiracy to suppress anti-glyphosate research.
With the industry-conspiracy narrative in place, Ryerson gave her personal testimony about the ill effects of glyphosate exposure. I call this genre of storytelling “postmodern medicine,” because its based entirely on the experience of a single individual, and words can take on any meaning necessary to make the story work. For instance, "chemical" doesn't mean, "Of, relating to, used in, or produced by chemistry or the phenomena of chemistry." It means, "Icky, yucky, feel-bad liquid." The word is often used to alleged that "we need to stop chemical farming right away."
You've heard these narratives before; see if you can spot the familiar themes from Glyphosate Girl's tale. Ryerson had a medical condition that she couldn't pin down. Her doctors couldn't explain it, so they put her on powerful drugs to treat her symptoms, which carried their own nasty side effects. Fortunately, she was introduced to a psychologist who gave her a vitamin panel during their first appointment.
The test revealed several deficiencies that explained Glyphosate Girl's mysterious maladies. After discovering the forbidden work of iconoclasts like Gillam and Bush, Ryerson's eyes were opened. The glyphosate-treated grains she ate weren't giving her the nutrients she needed, and the herbicide itself was damaging her gut microbiome. A few unnamed scientists later confirmed Ryerson's suspicions about the weed killer, off the record naturally.
I can't speak to Ryerson's personal health, but several of her claims are falsifiable. It's certainly true that traces of glyphosate show up in our food and the surrounding environment. If you peed in a cup, a reliable assay would almost certainly confirm that you've been exposed to glyphosate. That said, the quantities you consume through food can't harm you. Study after study (after study after study) has confirmed this observation.
The claim that glyphosate exerts any negative effect on gut health is dubious at best. Studies that expose microbes from the human gut to glyphosate only find “limited effects” at doses up to 50 times higher than the acceptable daily intake of the weed killer set by the European Union. Unless Ryerson swam laps in a pool filled with Roundup for months at a time, she wasn't exposed to enough of the herbicide to cause herself or her gut microbes any harm.
The mistakes went on and on. Senator Booker alleged, for example, that the EPA continues to register harmful pesticides for commercial use, presumably because its staff are asleep at the wheel or in league with chemical companies—a claim Gillam and Ryerson repeated during the discussion. This is absurd, of course. The EPA's registration process is rigorous and hardly hidden from public view. You can read all about it on the agency's website.
ACSH: Monsanto's little helper?
Much more could be said about the panel, but we've captured the essence of what was wrong with the event and the anti-pesticide movement more generally: it's driven by painfully ignorant, self-righteous busybodies who believe its their duty to remake the global food-production system. The hubris is so thick, you could pour it on pancakes.
Ryerson claimed that ACSH is a “front group” for Monsanto, paid to push “misinformation” that silences critics of the company's products. This has never been true, but let's put it to bed again with an invitation: I cordially invite any of the panelists to appear on our Science Dispatch podcast. You can have as much time as you like to say whatever you want, though you will have to defend your ideas.
Who wants to bet that Glyphosate Girl will take up my offer? If anybody shuts down that discussion, it sure won't be us.
 Dr. Bloom has hilariously recounted ACSH's previous dealings with Gillam in Living in an Altima Really Ain't So Bad
 Healthy cells don't divide indefinitely, limiting their usefulness in research. In contrast, immortalized cells are mutants that can be grown in-vitro for extended periods of time. This makes them useful from an experimental standpoint, but it also means they don't function like healthy cells. The effect observed in a cell-culture study may not actually occur in real biological systems, like a human body for example.