Some of the most vocal climate sceptics employ a very effective tactic when attacking those who want action on greenhouse gases. They try to show that the environmental movement, which is now so exercised by the threat of climate change, has made many substantial and costly mistakes in the past. Why, the sceptics say, should anybody believe the environmentalists on the issue of global warming when these people have been wrong about so many other things? The example of DDT is often used as an illustration of how wrong-headed scientists can cause untold suffering by their work. This propaganda needs a response. Here’s what James Delingpole wrote about this insecticide on 5th November 2010.(1)
‘The near global ban on DDT – inspired by Rachel Carson’s junk science bestseller Silent Spring – had caused millions to die of malaria.’
And then, a few sentences later
‘What ABOUT those millions and millions that Rachel Carson inadvertently massacred with her entirely unfounded claims about the effects of DDT on birdlife?’
Let’s work through these statements word by word.
a) ‘The near global ban on DDT.’ The word order is important. Delingpole presumably knows that there is no ‘ban’ on the use of DDT for use in disease prevention but that its use is prohibited in agriculture. So when he writes ‘near global ban’ he hopes that we misunderstand this to mean that it is banned across most of the globe rather than the correct statement that DDT is subject to a ‘global near-ban’ which restricts its application to malaria prevention.
b) ‘Rachel Carson’s junk science bestseller’. Silent Spring is one of the most influential books ever written and its publication in the US can be seen as the start of the modern environmental movement. Carson noticed a reduction in birdlife in many rural areas and blamed agricultural pesticides. Her work has been challenged many times, but no-one has ever contended that the core thesis of the book - immoderate use of pesticides had caused severe loss of wildlife - was wrong. Not even the most committed opponent of the restrictions on DDT says, for example, that the insecticide does not affect the reproductive success of birds at the top of the avian food chain by thinning the eggshell.
c) ‘Junk science’ The words ‘junk science’ are increasingly employed by the global warming sceptics to cast doubt on the validity of claims made by climate science. It is difficult to rebut epithets like this. Delingpole is trying to link his claims about DDT to his views about those people who want to reduce greenhouse gas emissions. He wants us unconsciously to absorb the message that all environmentalism involves ‘junk science’.
d) ‘Caused millions to die of malaria’. DDT continues in use in anti-malaria campaigns. Rapid progress is being made in many parts of the world on malaria eradication. Those countries where malaria is still not effectively controlled, principally in Africa, are losing the battle not because of a ban on DDT but because of poor public health provision and, for example, the growth of sunlit pools of stagnant water after deforestation. DDT is probably less used as an insecticide in tropical countries than it would have been had we not seen its effects on wildlife but Carson is hardly to blame for this.
e) ‘Rachel Carson inadvertently massacred’. Delingpole knows that most people don’t seen environmentalists as wicked but he can try to successfully portray them as gullible and dangerous fools. So he suggests that Carson didn’t set out to kill millions but her benighted adherence to her erroneous views caused great suffering. We are expected to understand that environmentalists concerned about global warming are equally misguided and destructive.
f) ‘Entirely unfounded claims about the effects of DDT on birdlife’. There probably isn’t a single scientist alive today who contests Carson’s central thesis that the effects of DDT are severe. Not all types of bird suffer from its effect but in addition to birds at the top of the food chain any creature, such as the robin, that eats earthworms is affected by the chemical. Carson was not the first to notice this. Here is the first paragraph of a 1958 scientific report by Roy J Barber.(2) The main purpose of this paper is to call attention to the possibility that moderate applications of DDT under certain conditions can be concentrated by earthworms to produce a lethal effect on robins nearly one year later.
Rachel Carson was a quiet, cautious person who carried out her science with precision and care. She never suggested that society should give up insecticide use but told us of the huge, unforeseen impact of massive and indiscriminate use of under-researched chemicals, often sprayed from the air in volumes that would now seem utterly horrifying. Climate sceptics that use her work on DDT as an example of the deleterious impact of environmentalists are profoundly mistaken. She represented science at its careful, thoughtful best.
Silent Spring is dedicated to Albert Schweitzer and carries his words on its title page. ‘Man has lost the capacity to foresee and to forestall. He will end by destroying the earth’. This sentiment is as relevant to today’s climate challenge as it was to the over-use of insecticides half a century ago.