Another Cafe Scientifique meeting, another urban myth. Strange, since the level of discourse at these talks is very good. The audience is made up of engineers, doctors, technicians, IT techies of various persuasions and other “skeptical” types in the best sense of the word, all of a certain age. Being Henley-on-Thames, that age is at the upper end, but none the worse for that; having been around the block a few times gives you a certain perspective on the issues of the day, especially if you have a questioning mind.
The talk itself was excellent, delivered by Dr. David Hughes from Syngenta and titled “Organic Food and Farming : Global Saviour or a Case of the Emperor’s New Clothes”. His thesis deserves a blog post of itself, but for today I will take a minor detour and respond in detail to a statement from one of the audience. And the proposition in question? The banning of DDT, championed by Rachel Carson in “Silent Spring”, has killed 5 to 6 million people through allowing the spread of malaria.
A few questions later I had the chance to stand up and refute the claim. But replying on the fly to an off-topic issue requires an ability to recall sources that I don’t have. But I did remember that Oreskes and Conway in their superb book “Merchants of Doubt” had debunked this meme based on the fact that resistance to DTT led to the decline in its use not—not an eco-campaign by Carson and her followers. And then Hughes countered that DTT was still being used today. Well, yes. Alas I was not fast enough to point out the contradiction: the ban of DDT had led to millions of death, but it wasn’t actually banned?
Actually, I doubt whether Hughes at the time had a well-formed view of Rachel Carson and DTT at all. But the questioner had fashioned Carson as anti-science. A case of the enemy of my enemy is my friend. But sometimes this just isn’t true.
Back at home, I re-read Oreskes and Conway’s Chapter 7 entitled “Denial Rides Again: The Revisionist Attack on Rachel Carson”. Here we learn that President Kennedy turned to the President’s Science Advisory Committee (PSAC) to guide him on DDT in 1962. The PSAC’s advise was to restrain the use of DDT. Ten years on it was under a Republican president, Richard Nixon, that DDT was actually banned in the U.S.
But Oreskes and Conway’s critical point is this:
…. the most important reason that eradication was that mosquitos were developing resistance. In the United States, DDT use peaked in 1959—thirteen years before the ban—because it was already starting to fail.
And this pattern was repeated abroad. Between 1948 and 1963, the application of DTT worked like a charm in Sri Lanka. However, malarial cases then ticked up again and by 1968 DDT was becoming ineffective. Nonetheless, the country’s health authorities persevered, but no improvement was seen even with larger applications. Eventually they gave up. But this was years after the United States ban, and not because of the U.S. lead: they gave up because DDT stopped working.
Nonetheless, a number of right-wing foundations such as the Competitive Enterprise Institute and the Heartland Institute have continued with shrill claims that the EPA’s banning of DDT has killed millions of Africans, Asians and Latin Americans, and Rachel Carson has blood on her hands. It just isn’t true.