The continuing relevance of Silent Spring

Published on 18 November 2014 in Letters

Jeremy Greenwood

Jeremy Greenwood

Recently, Conor Jameson suggested that we remember Rachel Carson annually on the anniversary of her death (Brit. Birds 107: 242). I would go further and suggest that we never forget the issues to which she alerted the world – and their continuing relevance.

Carson’s message in Silent Spring applied to the misuse of all pesticides but she concentrated on DDT because it was then widely used in the USA, often being sprayed over large areas from the air, and because it was promoted worldwide for the control of arthropods in farmland, forests, wetlands, gardens, hospitals and the home. She reviewed facts that were already well established but which the pesticide industry had largely hidden from the public: some of the organochlorine pesticides were dangerous to human health (though DDT is less dangerous than others); DDT and other organochlorines build up in food chains, so are especially dangerous for animals high in food chains (such as humans); and many insects were already resistant to DDT, so in many situations it was not working. She showed both that the industry had spread disinformation and that public officials had accepted industry claims uncritically.

Carson’s message in Silent Spring applied to the misuse of all pesticides but she concentrated on DDT because it was then widely used in the USA, and because it was promoted worldwide for the control of arthropods in many environments. She reviewed facts that were already well established but which the pesticide industry had largely hidden from the public: some of the organochlorine pesticides were dangerous to human health (though DDT is less dangerous than others); DDT and other organochlorines build up in food chains, so are especially dangerous for animals high in food chains (such as humans); and many insects were already resistant to DDT, so in many situations it was not working. She showed both that the industry had spread disinformation and that public officials had accepted industry claims uncritically.

The pesticides industry in America spent the equivalent of 1.5 million dollars trying to discredit the book. It was implied that Carson was seeking to ban pesticides that were safe if used properly – but she was not seeking a ban, merely more selective use to achieve pest-control objectives more efficaciously, with fewer health and environmental side effects (though, of course, with the side effect for the industry that less pesticide would be used – the real reason for the attacks on the book). Even before the book was published, the manufacturers threatened to sue the publishers on the grounds that it was inaccurate, an assertion often repeated by their spokesmen in reviews of the book. But Carson had already had everything checked by experts and none of her critics found a single specific inaccuracy.

The attacks descended into silliness: the book was dismissed as alarmist and emotional; it would appeal to ‘food faddists, organic gardeners, anti-fluoride campaigners, pseudoscientists and nudists’; Carson was a hysterical bird-lover, cat-lover, or fish-lover with no scientific credentials. This all backfired for, in truth, Carson was a qualified biologist with a distinguished career behind her. The seriousness of her approach was apparent when she appeared before a congressional committee, as it was to all those who were stimulated to read the book by the furore that the industry whipped up. In an allegation that was not only irrelevant to whether her science was correct but also quite without foundation, they accused of her of being a communist, a serious allegation in America at that time. Her response was simple: ‘Let the course of events provide the answers.’ The campaigning against the book gave it great publicity; millions read it and were convinced.

This should have been the end of the matter but in recent years there have been new attacks on Carson, claiming that she caused DDT to be banned, resulting in billions of deaths from malaria. This claim could not be more untrue. What in fact happened is that the widespread blanket spraying of DDT was not only rather ineffective in the fight against malaria (which demands more refined and selective methods) but was actually causing mosquitoes to become resistant, so making it useless even when used properly. It was for this reason that the Stockholm Convention of 2001 delivered a worldwide ban on DDT except for its use in the control of malaria. Why this campaign of lies against Carson? It appears to me that it fits in with continuous attempts by some pressure groups to undermine science generally. Their problem is that science has produced evidence of the effects not just of pesticides on the environment and health but, for example, of smoking on health, of CFCs on the ozone layer, and of the burning of fossil fuels on our climate. This has been inconvenient to those who want to minimise regulations in order to maximise profits. They have conducted vigorous, often underhand, campaigns over many years, not just on specific issues but to undermine science generally in the eyes of the public and decision-makers (see Oreskes & Conway 2010).

It would be wrong were scientists to determine policy. That is the job of politicians. But if political decisions are to be sound, then the scientific evidence should not be ignored or perverted. Policies will be ineffective if they rest on pretences such as that misused pesticides do not endanger us and our environment, or that man-made climate change is not happening, or that there is no evidence that neonicotinoids may be implicated in the decline of bee populations or, to take an example of the opposite hue, that genetic modification produces ‘Frankenstein foods’. Rachel Carson’s best legacy would be that we never forget the need for policies to rest on sound evidence.

Reference Oreskes, N. & Conway, E. M. 2010. Merchants of Doubt. Bloomsbury Press, New York.

Jeremy Greenwood, Bayview, Smithy Road, Balmullo, Fife KY16 0BG; e-mail jjdgreenwood@gmail.com