GM & glyphosate: Rachel Carson (sort of) speaks…

Well, thanks to those of you who commented on my recent annual vs perennial grains marathon. I invited Tim Crews of the Land Institute to respond, and he said he might, but it looks like he’s decided not to. So I guess the whole thing goes the way of many academic debates before it: ‘you’re wrong’, ‘no, you’re wrong’. And only time will tell. Though I’m quietly confident that in fact it is me who will ultimately prove to be right – a conclusion to which my research has pointed with remarkable consistency over the course of my career. Meanwhile, I think Ford Denison may be writing something about the debate, so it’ll be interesting to read that (STOP PRESS: here it is).

Anyway, now it’s time to move on – and what better topic to choose than plant breeding’s Scylla to the Charybdis of perennial grain breeding? Yep, you guessed it – GM crops.

OK, OK, I know I vowed to avoid this issue – one that’s so balefully polarised as to make any kind of productive debate with the other side seem impossible.  On GM, I have engaged amongst others with the ingenuous, the angry, the emotive and the merely vapid without worthwhile result. No more, I have said solemnly to myself, no more. But there are some new angles to explore, so the time is right for just one more whirl. Well, two in fact – I need to descend slowly from the giddy heights of those multiple linked perennial grain posts, so I’m going to acclimatise to normal service with a GM two-parter.

Part One concerns glyphosate, which isn’t intrinsically linked to GM technology in and of itself – except that, well, it kind of is, on account of the fact that glyphosate-resistant crops constitute about 80% of the GM crops grown worldwide1. All the talk of golden rice, Hawaiian papaya, Bt cotton etc somewhat blinds us to that brute fact. So if there are problems with glyphosate, then basically there are problems with GM crops, at least as they currently manifest.

And it looks like there may be some problems with glyphosate. One that’s received a lot of attention lately is a possible link to raised cancer incidence, as reported in this study. But there’s another set of interesting potential problems which have been outlined by Thierry Vrain, a retired Canadian government agricultural scientist.

Vrain has set out his thesis in an open letter to the Canadian minister for health. I précis it as follows:

1. Glyphosate is sufficiently persistent and ubiquitous in the environment for it to find its way into the human body

2. Glyphosate’s main action is to interfere with an enzyme possessed by plants and some bacteria and fungi but not by animals, so it doesn’t have acutely toxic effects on people.

3. However, glyphosate does have a toxic effect on the microbial population of the human gut, and may therefore cause chronic human ill health through impeding normal gut function

4. Glyphosate also has chelating properties, which may result in reduced availability of trace metals essential to a healthy human diet

Well now, I don’t know if he’s right but it strikes me as an interesting line of argument – albeit one that’s quite difficult to prove without costly chronic morbidity studies, which I don’t believe have yet been undertaken. I can think of various reasons why Vrain’s fears may prove unfounded, but I don’t think there’s yet any conclusive evidence against – a trawl through the internet reveals various dismissive screeds about his views such as this and this, which for the most part ignore his actual reasoning in favour of generic appeals to the ‘science’ in support of GMOs, while ridiculing the discredited ‘pseudo-science’ that Vrain invokes.

I’ll say more in my next post about science, pseudo-science and the discreditable practice of discrediting studies. But when it comes to a scientist raising questions about the wisdom of a mainstream agricultural technology and then getting this kind of blowback from the technology’s proponents, I get a funny feeling of déjà vu. Doesn’t it all sound a bit Rachel Carson – vilified in her time for daring to raise even the possibility that there might be a problem with DDT, but ultimately proved right? Whether Vrain will turn out to be right or not is of course unknown, but if he is then given the ubiquity of glyphosate we have quite a problem on our hands. So I assume that everybody would support the establishment of rigorous, independent, long-term studies to look into the issue. Well, everybody but those with a vested interest in GM. Monsanto is already calling for the cancer study to be retracted. Now why would that be?

Let me just reiterate my point about independent chronic toxicity studies. GM proponents like Steve Savage and Graham Strouts have invoked the spirit of Rachel Carson to their cause, implying that GM crops and/or glyphosate are safer than the biotechnologies of yore and Carson would have supported them. As I’ve argued previously, this strikes me as a somewhat sneaky tactic to appropriate an environmentalist icon to their own particular agenda and thereby clothe it with the reflected legitimacy of her name. And, being dead, Carson conveniently lacks a right of reply. Well, I don’t have the temerity of Strouts to ventriloquize with such confidence what Carson would have supported, but given the nature of the battle over DDT I suspect that if she were alive today she might well be calling for rigorous, independent, long-term studies to investigate a possible association between glyphosate and chronic human morbidity. So I’d hereby like to invite Steve and Graham to gather together with me in homage to the spirit of the woman that we all revere and join me publicly in that call so that Vrain’s thesis can be tested.

Meantime, I think I’ll put my plans to incorporate glyphosate into organic farming on ice…


1. Or at least it did around 2008, according to this paper: If anyone has some more up to date figures, I’d be keen to see them.

15 thoughts on “GM & glyphosate: Rachel Carson (sort of) speaks…

  1. Ah, welcome back – and in less than 3 weeks. Such fortitude!

    On the issue of glyphosate’s market presence – I’m guessing it may be at a peak. And the rate at which there is push back from the high water mark will likely come more from weed resistance than from cancer scares or other ‘poisoning’ possibilities of the chemical itself. Before an outpouring of joyous noise about ‘death of the monster’ it may be worth note that a couple of ‘replacement’ technologies still contain glyphosate. [insert picture here of me with my 27 year old hoe – inscribed with “selective weed control – still no resistance” 🙂 ]

    If I were to throw in with the “what would Rachel say” crowd I’m imagining she’ll be rolling here eyes. Much of her effort took on some really nasty chemical insecticides (chlorinated hydrocarbons) which have shown significantly greater dangers than glyphosate has. But also within the folds of her philosophy were stabs at our hubris and cautions against reckless headlong pursuit of conquering Nature. Thus I can see you sharing a bench with Steve and Graham in homage to Ms Carson. As for Thierry Vrain’s concerns, it may be best to get going on some of the next generation of herbicide solutions. Quite a bit has been done, and they are passing all the current known milestones expected of such products (which is a longer list then it once was). It seems only right to me that Thierry should be lauded for asking the question, not pummeled or cast as obstructionist.

    • I think you’re right that weed resistance will be the main driver of glyphosate’s decline, but the health issues are interesting – perhaps we’re in the realm of “less nasty, but still quite nasty”? Interesting on next generation herbicides…and on Carson’s wider philosophy. Will the next generation of herbicides soon fall by the wayside too because we still haven’t conquered our ‘conquering nature’ affectation?

      • You ask: Will the next generation…

        Well, if I had a crystal ball worth anything I’d be rich and famous. As I meet neither of these it suggests my vision of the future has always been suspect. But this restriction has seldom prevented me stabbing at what may come to pass.

        I think I’d be on fairly solid ground suggesting the next generation of herbicides will fall by the wayside due to the evolution of weed resistance. “Soon” is a tough metric to work with in this realm. Different chemistries have had varying rates of resistance buildup. But relying on this ‘natural’ experiment is complicated by factors such as technology deployment (rate and expanse), and other agronomic practices (no-till and reduced till practices have modified the spectrum of weed species being ‘fought’). Some have suggested if we learn from past experience and do a better job of trait stewardship we can delay the onset of weed resistance (some may suggest ‘prevent’ vs my use of ‘delay’… but that strikes me as so much hubris).

        My own level of hubris shows through by considering that even in the face of a limited lifespan for technologies now coming down off the drawing board, I think we as a species will conjure yet other technologies or solutions to the difficulties that confront us.

        Can we come to a place where we might abandon our affectation to conquer nature? An interesting question. I wonder if such a place is even ‘in’ our nature. Your own background in sociology probably speaks to this better than anything I can suggest.

        • A nice ball to toss back into my sociological court – and the answer, based on the most rigorously scientific of sociological research, is a firm ‘no’. Though actually I might be inclined to venture the opinion that ‘nature conquest’ is really an epiphenomenon of the pursuit of social power, which is a sufficiently complex and contradictory beast to prompt the thought that the ideology of nature conquest may be tamable, even if not wholly eradicable (which may be just as well). And another blog post starts brewing…

          • Like many subjects we might mean to tackle through data collection and summary I’d argue we’ll want to be rather circumscript in defining our terms. Nature conquest is an attribute that might be ascribed to all sorts of other critters – particularly top predators. And it might be argued that our distant ancestors learned to hunt in packs by observing other predators doing this. But regardless of minutiae – as always I’ll be looking forward to any follow-up contributions from this space.

          • Interesting – I’d be inclined to argue that top predators are oriented more to ‘prey conquest’ than to the more generic ‘nature conquest’. The ideology of the latter can encompass things like building skyscrapers and dams, halting degenerative diseases or reversing infertility, as well as developing pesticides or shooting tigers. And while other critters do engage in behaviour which attempts to subvert the biota to their ends, do they espouse ideologies of nature conquest – ie. a prior framework of ideas to organise their behaviour? As Marx put it “what distinguishes the worst architect from the best of bees is this, that the architect raises his structure in imagination before he erects it in reality.” Though perhaps that’s not to give bees their due?

          • I see where making deliberative plans may elevate our conquering a bit beyond the conquering done by other species – but then one might also argue we deserve some credit for planning ameliorative activities to repair/replace damages inflicted. But here too there are examples of natural systems repairing/rebuilding after natural disaster.

            Using herbicides to kill weeds is basically deploying a poison – venom if you will. Where H. sapiens goes beyond the rest of creation might be in the extent to which we conquer. Our knowledge of chemistry and physics allowing us to synthesize chemicals or control fission for our purposes do go far beyond the capabilities we’re aware of for other residents. But on any scale there is at least one observation at the most extreme point. For nature conquering, we seem to have the poll.

            But let’s turn the prism a bit… For all its history the winner of the Boston Marathon has been a male Homo sapien. But a male Homo sapien has never won (by running) the Kentucky derby. What species might prevail in a Kentucky marathon derby if all species could enter? Yes, this is a bit ridiculous… but on matters of nature conquering we have compared all creatures great and small in the same contest. Would it make more sense to compare within our species alone for degrees of conquer and degrees of repair/facilitate/share, etc. ??

          • I suppose much depends on the purpose of the comparison. As I’ve argued elsewhere I think humanity is caught in a somewhat tragic contradiction of ‘part of nature/apart from nature’, the tragedy inhering in the fact that we are aware of it. But I think it may be possible, and worthwhile, to kick the ‘nature conquest’ instinct, at least to a greater degree than we’re currently willing – though not easy. An issue I hope to raise in more detail here later in the year.

  2. A tendency to ” ignore his actual reasoning in favour of generic appeals to the ‘science’ in support of GMOs” is deplorably common, as in a recent op-ed in NYT. GMO opponents are sometimes equally lacking in nuance.

    So I appreciate how you evaluate each issue on its merits, rather than blindly accepting any one tribe’s dogma.

    • Thanks Ford – I agree on the dangers of both tribes’ dogmas. My next post will try to pick up on that some more in relation to the way we talk about science.

  3. I was open to Vrain’s argument until this:
    “Nancy Swanson has made public her statistical analyses of the US Centre for Disease Control’s statistics about the health status of America when placed next to the statistics of the US Department of Agriculture about the spread of RoundUp Ready soy and corn. Her correlation analyses show very high coefficient values suggesting strong links between glyphosate residues in RoundUP Ready food and chronic illnesses.”
    The all-too-common correlation morphed into “strong links” argument. When a scientist resorts to this argument (or even uses it as part of his argument), you have to question the motive and/or the strength of his case. How many other factors are correlated with these chronic illnesses? I would guess that blog posts are, but would not accuse you of affecting anyone’s health.

    • I haven’t looked at Swanson’s analysis so I can’t comment for sure, but a lot of epidemiological work is based on correlation as a proxy for causality – if the cases/controls or exposure groups are defined with sufficient precision, then correlation indeed can imply a strong link (eg. Snow’s work on cholera, or Doll’s on lung cancer). But of course you’re right that there’s a lot of potential for spurious correlations if you don’t define your parameters properly.

  4. Hi Andy:
    I must say, I was open to your argument until this:
    “How many other factors are correlated with these chronic illnesses? I would guess that blog posts are, but would not accuse you of affecting anyone’s health.”

    Is that really the way you want to represent yourself?

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