Brian Dunning’s DDT Fail


A few weeks ago, Brian Dunning of Skeptoid posted a podcast that made a variety of claims about DDT and Rachel Carson’s book Silent Spring that were poorly researched and factually incorrect.  For a while Dunning refused to admit his error; the podcast page as of 11/23/10 now has a box at the bottom in which he distances himself from the DDT claims he made by saying “Skeptoid is not here to tell you what to think.”

I and a few other people have been writing for several years about the way in which right-wing groups have been promoting DDT and attacking Rachel Carson. I could easily do a point-by-point fisking of Dunning’s mistakes (which others have done ably; see links at the bottom of this post), but I think the most useful thing to do would be to examine why a prominent skeptic fell so hard for a bogus manufactroversy.

Manufactroversy (măn’yə-făk’-trə-vûr’sē).  A manufactured controversy that is motivated by profit or extreme ideology to intentionally create public confusion about an issue that is not in dispute.”

You see manufactroversies all the time in the media– “Teach the Controversy!” “Global Warming is a hoax!” “Vaccines are poison!”  The common thread is creating a controversy even though a clear consensus exists within the scientific community.

Media likes to frame issues as a debate: if you can get two talking heads to argue, that’s great TV. The problem is, presenting both sides of an argument is silly when there is no actual lack of consensus.

Dissent is manufactured by using information out of context and/or finding a scientist that opposes the prevailing view. That lone scientist’s opinions are then given equal weight to the majority of scientists who don’t think using DDT indiscriminately is a good idea. Or that Global Climate Change is a real and major threat to ecosystems.  You get the idea.

Manufactroversies also exploit the way in which scientists are constrained to speak in probabilities, not absolutes.  It’s part of the language of science to say that something may be true, almost surely IS true, but there are caveats on the conditions under which something is true. Scientists also have to make statements open to revision based on new information.

That’s part of what Skepticism is all about, too–forming opinions based on the available evidence.  New Evidence? Re-assess your conclusions.  This is not, alas, how many major media outlets–or politicians–operate.

The primary source Dunning seems to have used for his DDT fiasco is a website called Junkscience has an amazing history, and a little follow the money helps to connect cigarettes, lobbyists, anti-environmentalism, and an astroturf group called Africa Fighting Malaria.  Why didn’t Dunning pick up on those red flags? I don’t know.

The reality of DDT and malaria is that it is an incredibly complex problem.  There isn’t only ONE species of malarial parasite (Plasmodium). There isn’t only ONE species of malaria mosquito. There is not just ONE kind of ecosystem in which birds, mammals (including people) and malaria interact.  There is not just ONE political and health care system in areas where malaria occurs that is optimal for managing treatment.  In fact, in some areas where malaria occurs, there is no effective political or health care system!

Each system is different, and that is why blanket statements that portray DDT as a panacea for solving malaria problems are false and, frankly, stupid.  The issue of insecticide resistance is not trivial. We have many tools in our insect control toolbox; we need to choose each chemical carefully based on the best chance of control within a particular context. Making the wrong choice can have serious consequences if resistance occurs, and we loose the use of a pesticide.

When people espousing careful examination of data before making an insecticide choice are attacked for promoting “genocide”, you have to know something else is going on.  There is a political agenda at work.

I can guarantee you that within 24 hours of this post, there will be at least one, probably more, commenters that will accuse me of racism (“you want to kill brown people in Africa!”) or of lying about DDT.  They have shown up all over my blog whenever I bring up the topic of DDT and Rachel Carson.  Their primary methodology is copy/paste of the same old tired arguments over and over.

These are not people interested in nuance or conditionality of conclusions. They are people that find information that fits with their already existing world view, and then adopt it. Because it supports what they already believe.

Carson’s principal thesis was that broadly biocidal chemicals should not be carelessly introduced into the ecosystem.  She also said this: “It is not my contention that chemical insecticides must never be used.”  I don’t think many here would disagree with those statements.

Had Dunning actually READ Silent Spring, he might have realized his own words were wildly incorrect: “Silent Spring’s principal thesis was that DDT harms bird populations through eggshell thinning.”  In fact, the evidence for eggshell thinning was not published until after Carson’s death from breast cancer in 1964. (Also, when writing a critique of a book, it helps if you actually read the fucking book. But I digress.)

Dunning clearly got his information second-hand. And it was bad information.  This should be a lesson to all of us to check our sources carefully, and ask questions about “Who Profits?” and “What’s the Motivation?” about everything we read.  And to be willing to own it when we screw up.

Suggested resources:

The Science:

The Politics:

28 thoughts on “Brian Dunning’s DDT Fail

  1. Thanks Bug Girl – you’ve demonstrated that science, through scientific skepticism, is a self-correcting process, where no single individual, organization or group can be immune to review and critique.

    I love how skeptics keep each-other in check as we can all fall victim to bad research, especially when we’re not specialists in the field.

    Lucas (Codenix)

  2. Simon

    Uh oh, Bug Girl! Are you sure you’re “paddling” and not just “dragging” ? Dunning doesn’t like it when people call him out publicly, you know, as it “hurts the skeptic movement.”

    No, in seriousness, I’m glad you and others have thoroughly examined his claims. This is crucial to the process of presenting good information, and is just good science, despite his previous claims (which may indeed have changed in the year since he posted that irritating diatribe).

    That no claim by anyone is above criticism is one of the greated strengths of the skeptic “movement”, and you and others deserve great praise for pointing out inaccuracies wherever you find them, and regardless of who makes the claims.

    Thank you.

  3. I first encountered Rachel Carson’s books in high school while reading my way through the library biology shelves. The books on the sea were grand. The only disappointing thing was that there were so few, but Silent Spring was the third and last. What a bummer for someone who had already decided to become an entomologist and save the world from malaria. Good thing biocontrol was making one of its periodic resurrections by the time I got to uni. Of course, some people think biocontrol a disaster too.

    DDT saved a lot of human lives, but also did untold environmental damage when used as a panacea sprayed everywhere on everything. Rachel Carson wrote a book that pointed out we were using DDT and other chemicals irresponsibly. The book and its obvious truth had a major impact, especially on the use of DDT. I’m pretty sure, though, she wasn’t saying chemical pesticides are bad, just that we were screwing up pretty badly with our use of toxic and broad spectrum chemicals. That’s how I remember it anyway.

    I used to get depressed observing that people always needed to crush complex issues into simple black and white dichotomies and then to demonize the side they disagreed with and promote their heroes to sainthood. Now I think it is sort of interesting in a depressing way, especially how the people on either side seek confirmation of their opinions and ignore any contrary facts. Perhaps facts really aren’t important and it is only those who can scream the loudest and nastiest who are actually correct. I bet this approach works fine for howler monkeys and chimpanzees too.

  4. Michael5MacKay

    Excellent summary of what the issue is about.

    Over at Skeptic North ( I reviewed Naomi Oreskes and Erik Conways’ Merchants of Doubt, which has a good chapter on the attempts to demonize Rachel Carson. I found it a more balanced and compelling analysis of the topic of DDT.

  5. stogy

    I have to say I was indebted to you and the resources you linked to on DDT when I took on

    It’s not quite my area, but I think I did OK.

    Love the site – even though I seldom comment. Thanks Bug Girl!

  6. It’s Thanksgiving and I’m thankful!

    Wonderful post. Clearly and logically argued. I am incredibly grateful to you, to Garden Rant, and to all the others who fight for the ideas I believe in. I’m not a good fighter, so as I said I’m thankful for you guys.

  7. BioBob

    It’s is an uphill battle to persuade the purveyors of the Rachel Carson = murderer of millions Bates meme, and I suspect we may have marginal success trying. The best counter may indeed be “read the fucking book” lol.

    However, I think you are employing poor word choice with “consensus”. Consensus is meaningless in Science. The exception makes the rule in science. Consensus is the dirty word employed in AGW, another corrupted manufactured controversy. Instead one could simply point out that Carson never said that shit, DDT was never banned for use on insect vectors, etc. etc.

    A simple “You LIE !” and “Read the Fuckin book, doofus!” works for me though, hehe.

  8. I was thinking more of evolution and global warming, BioBob.
    A consensus that has stood the test of time is about as good as we can do–and that will, of course, be subject to revision with new data.

  9. BioBob

    Yah, I gathered so.

    However, AGW is a poor choice to include in “consensus”, imo, since it is likely neither human caused nor global, in reality. AGW is based on inadequate and badly manipulated data [see climategate esp "harry read me"] and unfounded supposition, and can hardly be said to have stood the test of time since all/any ave temperatures have not gone up for more than a decade while the CO2 concentrations continue to rise merrily. In any case, temperatures have never been observed rising globally but rather in some high arctic latitudes [and cooling in high antarctic latitudes] and in some small patch or another. Instance after instance of unfounded data manipulation (eg lowering early temps and raising later temps in “adjusted” data) and cherry picking has been observed and publicized at sites like WUWT. Not only is this bad science, but it is also obvious and blatant FRAUD.

    After all, it was merely ~30 years ago that many in science and media were sounding the warnings of a coming ice age, lol. In point of fact, such newspaper alarmism has strong correlation with the PDO and ADO cycles, which I find quite interesting, cycling between visions of coming ice ages and unfortunate droughts / warmings.

    The very concept of a global average temperature is totally absurd. Life has persisted for hundreds of millions of years of climate and CO2 concentration change and will continue to do so until the sun’s or some other cosmic event’s behavior ‘decides’ otherwise.

    Regarding AGW, get back to me in another 50 years since climate is more a matter of thousands of years rather than a decade or three, and the current peculiar solar behavior could well have snuffed the current “warming crisis” in something comparable to the “Little Ice Age” or Maunder minimum [hopefully not worse]. I certainly see nothing in climate behavior to unduly worry about at this point. It is as inconstant and difficult to predict as it ever has been.

    The science of AGW is a pale shadow of that of evolution however, with over a century of an elaborating web of confirmation formed by every aspect of biological science.

    [ As an aside in regard to the Bate's types, I simply also point out the KNOWN 200,000+ annual acute poisoning deaths from pesticide poisoning, especially the more dangerous organo-phosphates which Carson also warned about, without necessarily mentioning the millions with less acute pesticide effects. ]

  10. Deltoid would be interesting in a depressing kind of way if it weren’t so puerile. I hadn’t visited the site before, and I’m a bit embarrassed that an Australian seems to be involved. Although I have watched Question Time in Parliament, so I guess I shouldn’t be surprised. I probably should run the virus checker though.

  11. Jeff Harvey

    From one entomologist to another I wish to thank you Bug Girl for your efforts on this thread and on others. You might know of me – I amd a senior scientists in Holland who regularly wades into discussions on Deltoid where I try and counter some of the anti-scientific rhetoric there on issues relating to biodiversity and its importance in sustaining human civilization. As for Dave’s comment (#14), it is to be ignored. He has not got a clue what he is talking about.

    One final point to add here. People like Dunning are actually doing a disservice in that they appear to argue that humans effectively have two choices – one in which we must forever simplify natural systems in order to achieve ‘progress’, and another in which we conserve nature with costs in terms of human welfare. This kind of choice is idiotic, for the simple reason that these trade-offs really do not, or should not, exist. Humans are simplifying nature at an astounding rate. Every time we drain a wetland, or clear-cut a forest, or destroy another hectare of rainforest, we push systems closer to a threshold beyond which they will be unable to sustainably generate a range of services which allow us to exist and to persist. I am not saying that development must be stopped indefinitely; I am saying that the choice is not black and white, one between wild places and people. Given the fact that human survival utterly depends on nature in all of its complexity, it seems to me to be the sprint of folly for anyone to argue that the current expansionist path can be sustained forever into the future without repercussions. We are already well into a period of consequences.

    Lastly, as I said earlier in Deltoid today, DDT anbd other organo-chlorine pesticides are bioaccumulative. This means that concentrations of these toxins build up in higher trophic levels, particularly in vertebrate-based food chains. Humans are at the terminal end of the food chain; the consequences of unlimited use of pesticides on human health should therefore be patently obvious.

  12. BioBob

    LOL – we will just have to agree to disagree, my dear – which I find perfectly agreeable. All the tempest in the teapot will resolve itself as climate does what it does so well – changes.

    I prefer to get my science from fellow scientists, if you please. There it is quite obvious that AGW is cant and religion, as one after another hyperbolic claim is exposed as fraud.

  13. Jeff Harvey

    Biobob writes:

    “many in science and media were sounding the warnings of a coming ice age”

    This is a complete and utter myth that has been debunked numerous times before. Moreover, those few scientists who did express concern over the effects of aerosols in cooling climate in the 1970s did what any good scientists do as more data come in: they changed their minds.

    Lastly, BioBob, which scientists are you referring to when you say, “I prefer to get my science from fellow scientists, if you please”. I guess you mean a few contrarian shills and outsiders who publish very little, if anything, in the peer-reviewed literature? Or else a bunch of old, retired scientists with time on their hands? As it turns out, speaking as a scientist, I also prefer to get my information from my fellow scientists and from the empirical data they generate and publish in rigid scientific journals. And the vast majority of those data strongly suggest that humans are forcing climate. Of course climate changes over time but that is not the point. The point is how fast a largely deterministic system can change. The largest body of accrued data suggest that current changes are occurring at rates well beyond those naturally occurring for such a deterministic system operating over enormous spatial and temporal scales. But, like most of those in the denial camp you do not appear to understand the concept of scale.

  14. Oldfart

    Biobob is apparently living proof that the compartmentalized mind can be perfectly rational on most topics and completely irrational on others. Biobob defends his (apparent) love, evolution against the attacks of the deniers but jumps off the cliff with the rest of the lemmings when it comes to AGW. Amazing creatures, humans. How did we ever survive (or have we?)

  15. BioBob

    @Jeff Harvey Myth ? rofl, I could post several actual links to Ice Age nuts in the 70′s but why bother? They were just as nutty as today’s AGW religionists. We have AGWarmist today who say AGW could lead to an ice age, LOL. AGW can do anything apparently – raise the temps, lower the temps, make it snow, increase drought, decrease drought, melt glaciers, build glaciers, wipe out [pick one] hundreds, thousands, millions, of species, melt the greenland and antarctic icesheets (oops, antarctic is increasing), acidify the ocean (oops, photosynthesis decreases local pH but most biota do as well at lower pH), flood Manhattan’s west side highway by 2010 (oh wait !! its not flooded now — ok, scratch that one), raise the rate of sea level rise (ooops, forget that one), increase hurricanes and tornado’s (disproved, so sorry), wipe out polar bears (oops, their pop is increasing, forget that one), and trim nosehair. OK, I made up the nosehair one!

    I read science from those publishing climate studies with a critical eye. Those making conclusions based on obvious fraud, I tsk tsk at, and there are so many. There is some good science mixed in there and some of it is quite interesting. Too many make stupendous leaps of logic tho, making claims unsupported by their data and statistical analysis.

    I fail to see how anyone can say more than the following:
    1) CO2 conc have been increasing in recent years,
    2) It is possible that human activities are responsible for this increase but more definitive info is reqd before certainty is possible, in particular the effects of ocean temps on outgassing, etc
    3) temperatures have increased since the last glacial period and we don’t know why, but we have some theories
    4) some places on earth are getting warmer but others are getting colder or staying the same but our instrument record is pitiful and inadequate to make any conclusions other than in some 1st world nations, and badly confounded by poor methodology and analysis even there.
    5) it seems like the arctic ice sheet is decreasing in size but our baseline data is only 40 years old and not especially accurate and in any case we don’t know why,
    6) however, the antarctic ice sheet is getting bigger and we don’t know why,
    7) the ocean height increased following the last ice age but the rate is pretty low now, about 1-3 mm per year, and we are not sure why,
    8) our Greenland and Vostock ice core, and etc proxy data shows that our current temps are consistent but not exceptional compared to both recent and prior inter-glacial periods, but we can’t actually relate the proxy data to absolute temps,
    9) shorter scale proxy records indicate that periods such as the Medieval and Roman Climate Optimums, were at least if not warmer than today, but we don’t know why,
    10) we don’t actually know an awful lot about climate and what affects it nor the weather, as is evidenced by the low quality of our forecasts, which are generally wildly inaccurate more than a number of days in advance. Our long range models are pitiful and wildly inaccurate, in reality.

    If you think climate is a deterministic system, I have a bride to sell you – cheap – before it gets submerged by that massive increase in sea level— i mean nosehair.

    Show me ONE paper that experimentally confirms CO2 directly responsible for the observed increase in atmospheric or oceanic temperatures someplace – does NOT exist. I will show you analysis after analysis of specific temperature station data “adjusted” to increase recent temps and decreasing older temps for absolutely NO REASON. FRAUD. I will show you temperature data from station after station failing to adjust for urban heat island effects like asphalt under and AC units exhausting directly onto sensors – FRAUD. I will show you papers like Mann’s hockey stick paper where instrumental temp data was stuck on the end of tree-ring data as if all the data was the same – FRAUD.

  16. Jeff Harvey


    Your latest effort is full of anti-scientific gobbeldegook. Again, you have not the faintest idea of scale. Of course climate control over vast spatio-temporal scales is largely deterministic. Just as the factors that regulate the functioning of biomes is also deterministic. Only when we reduce the scale sufficiently do proceses become stochastic. Certainly we know enough about climate to know that increases in the mean temperature at the current rate require some kind of forcing, and the humnan fingerprint is all over the current forcing. I have spoken with enough of my scientific peers in the field of climate science to gauge the significance of the human contribution. I certainly do not listen to a few shills and a few emeritus Professors outside of the scientific mainstream who repeat the same mantra. You claimed in your last posting that you listen only to scientists. What scientists? The vast majority of us who are working scientists (me included) agree with the broad consensus 0 meaning more than 90% of our peers in various fields – who feel that enough empirical evidence has accrued to show that huamns are forcing climate. What is so startling, given what we do know, is that a well-funded agenda-driven side that hates science has managed to give the impression that climate warming and the human component in it are ‘controversial’. What we don’t know very well is what the likely outcomes of anthrpogenic-driven climate change are likely to be. However, given our dependence as a species on a range of supporting ecological services, and the fact that, along with a suite of other human assaults across the biosphere, climate change is likely to unravel food webs and weaken ecological communities, I think that even if there were only a 10-20% chance that the current ‘experiment’ – for it is that – would end in disaster should be enough for humanity to take whatever actions are necessary to mitigate it.

    Let me ask you this: what qualifications do you poissess in ANY scientific endeavor? I ask because its clear from your rather simple posts here that you do not grasp even the basics. What’s worse is that you think you do, probably on the basis of reading a bit of the denial literature, and fusing that with your own personal biases. And for someone who probably has no relevant qualifications in the field, throwing around words like ‘FRAUD’ takes remarkable hubris. But, then again, I am used to denialist blow-hards huffing and puffing with little substance. Moreover, what evidence do you have that the Medeivel Period was warmer than today? ClimateAudit or guff produced by McIntyre/McKitrick? Many proxies support the data shown in Mann et al’s Nature paper. And the fact is that most biota do not do well at lower pH values if they are adapted to higher ambient pH levels. Again, adaptation is not an instantaneous process and most species and genetically distinct populations are locally adapted to a certain range of conditions. Certainly, species can adapt to changes in the environment provided the time frame is sufficient. One century is well beyond the capacity of many species to respond to the decrease in ocean pH, a process which would normally span millenia and not a century. And changes in pH represent just one of many human assaults on marine systems. We have decimated numbers of species at the terminal end of the food chain, and, given the importance of trophic cascades in mediating the function of marine ecosystems, this will just be exacerbated by chemical changes occurring as a result of increasing atmospheric concentrations of C02. But, to reiterate, you do not understand the importance of scales in ecophysiological processes. I might as well be debating with a kindergarten student.

    C02 has also been known to be a major forcing agent of climate since the time of Arrhenius, and, as Naomi Oreskes has pointed out numerous times, eminent scholars like revelle and Keeling discussed the impacts of increasing C02 on climate more than 50 years ago.

    Summing up, your arguments above are so weak that its hard to know where to begin dismantling all of them. As I said in my last post, the only concern in the 1970s over cooling, that was restricted to a few scientists, was based on the fact that the planet was entering a natural cooling cycle (now altered dramtically by humaniyt) and that aerosols were also affecting global climate patterns. But most scientists changed their mind when it became apparent that, by greatly increasing atmospheric levels of C02, the end result would be a switch to a warming climate. And the predictions have been borne out. Moreover, people like Keeling argued that, due to global atmospheric circulation, higher latitudes, especially the Arctic and boreal regions, would warm much faster than lower latitudes. Time has proven this to be true.

    Biobob, you and your ilk are out on a limb that is getting weaker and weaker as more and more empirical data come in. 2010 is about to beat 1998 and 2005 as the warmest year in recorded history (by quite a margin I may add). All kinds of biotic indicators show that it has warmed appreciably over much of the northern hemisphere since the 1980s. So I dispence with you ‘science’ and will stick to that published in the pages of many rigid peer-reviewed journals.

  17. @bug_girl, I had not been to your site in a long time, but after reading this I’ll be a regular reader again. I love your term, “Manufactroversy.”

  18. Matt

    Bug Girl, I wonder if you intend to post a response to Brian’s commentary regarding the small controversy his episode about DDT seemed to stir up in the skeptic community. I think it only fair that you respond publicly since you posted this (I’m assuming, of course) without contacting Brian first. At the very least, I think it may be a good idea to go ahead and do that point-by-point fisking you mentioned, especially since it could be “easily” done.

  19. Since when have people been required to contact folks they don’t know to tell them that they are wrong on the internet?

    I actually chose to take what I *thought* was the high road–to try to see why Dunning made the mistake and what we could learn from it, rather than flog him point by point for the many errors.

    I (and others) have ALREADY shown where Dunning makes mistaken assumptions and errors over the last 4 years of our blogging about the DDT issue. I honestly don’t know that it’s worth my time to lay it all out again, since Dunning’s clearly not interested in learning or changing his opinion.
    I also don’t particularly want to feed Dunning’s martyr complex.

    I do plan to do some holiday blogging (alas, the working for pay thing cuts into my writing time) about the Malaria issue of Nature. In other words, using peer-reviewed journals, not Wikipedia, as my primary source material.

  20. I was reading this:
    and realized another way to think about why Dunning got suckered. People like stories–and there is a full and complex narrative in the “environmentalists are blocking DDT and killing people” meme. It’s a story with good guys and bad guys, and documented “history” laid out and repeated (sometimes verbatum) across the net.

    The reality is a bunch of grey, with complex and scattered bits of information buried behind journal firewalls and inside dense scientific documents.
    And our monkey brains find that inherently unsatisfactory.

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