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.com. 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: