Poisonous Pen

Silent Spring,
by Rachel Carson,
USA, 1962

ACCORDING to Greenhouse guru Stephen Schneider, activists wanting to reduce emissions of "greenhouse gases" "need to get some broad-based support, to capture the public's imagination.  That, of course, entails getting loads of media coverage.  So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we may have".

Schneider's honest admission of the tactics of some in the greenhouse controversy neatly sums up Rachel Carson's 1962 book, Silent Spring.  The book can best be described as a well-written catalogue of disasters, real and perceived, caused by the use of newly-developed pesticides during the 1940s and 1950s.  On page after grim page, there are stories of dead fish and dead birds, of accidental poisonings and potential cancers, and of nature striking back.  The scenarios are scary, the statements simplified and dramatic, and doubts are conspicuously absent.

The publication of Silent Spring was a watershed for the environmental movement.  It sold over a million copies and fuelled the campaign that ultimately led to the banning of DDT.  Directly and indirectly, it generated the community hysteria about minute quantities of synthetic chemicals in our food and environment that envelops us today.  Silent Spring raised environmental consciousness, and it is still referred to as "prophetic" and "classic" within the environmental movement.

Carson highlighted several issues in her book: the use of persistent synthetic chemicals, the possibility that these and other synthetic chemicals may be carcinogens, the threat to biodiversity posed by large-scale use of pesticides and herbicides, the development of resistance among target species and the possibility that upsetting the balance of nature will create more problems than are solved.  A recurrent theme of the book is that Mother Nature is benign and bountiful and that all will be well if only we work with her.

Many of the points Carson made are valid.  Indiscriminate use of pesticides and herbicides can reduce biodiversity in managed lands.  Predator species can be killed as well as prey.  Exposure to large doses of some pesticides and herbicides can be fatal.  Pest species can and do become resistant to the chemicals used against them.  For these reasons, agricultural chemicals should be used carefully and thoughtfully.

However, Silent Spring ignored the benefits of pesticides and herbicides.  Hundreds of millions of people owe their existence to the use of DDT against the vectors of such diseases as malaria and yellow fever.  Fungicides protect potatoes from the blight that devastated Ireland last century and they protect us from the aflatoxins that could otherwise give us cancer through our peanut butter and bread.

Farming relies on reducing biodiversity.  Pests are species that compete directly with humans for the plants and animals raised on farms.  The use of agricultural chemicals has enormously increased the productivity of existing farmlands.  By reducing the amount of new land that must be cleared to feed the exploding human population, the use of these chemicals helps to maintain biodiversity elsewhere.

Carson proposed alternatives but neglected their inherent problems.  Biological control has an important role to play in managing pest numbers.  However, the cane toad is testimony that this strategy is not without its dangers.

The use of "natural" pesticides is not necessarily less risky than the use of synthetic ones.  About half the natural pesticides tested for carcinogenicity give positive results.  Breeding pest-resistant strains of food crops, as advocated by Carson, has the disadvantage that these chemicals cannot be washed off.

Rachel Carson died in 1964, years before the campaign against DDT culminated with its banishment.  However, many others have stepped forward to carry the torch that she lit.  Greenpeace is currently campaigning to have all chlorine chemistry banned (nearly half of all chemicals used today either contain chlorine or were made using chlorine), and the Dutch and German Governments are considering banning zinc from the building industry because of its "ecotoxicity" (zinc has been present in the environment since Earth's creation and is a vital trace nutrient with a recommended daily intake of 15 mg).  As with Silent Spring, these campaigns dramatise the risks without considering the benefits.

Civilisation has depended on the use of dangerous materials ever since our ancestors discovered fire.  Where there are problems, the solutions are usually to learn the proper handling procedures, not to ban their use.  That is the ultimate conclusion that Carson should have drawn.