Silent Spring at 40

Rachel Carson's classic is not aging well.

Ronald Bailey | June 12, 2002

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Carson was also an effective popularizer of the idea that children were especially vulnerable to the carcinogenic effects of synthetic chemicals. "The situation with respect to children is even more deeply disturbing," she wrote. "A quarter century ago, cancer in children was considered a medical rarity. Today, more American school children die of cancer than from any other disease [her emphasis]." In support of this claim, Carson reported that "twelve per cent of all deaths in children between the ages of one and fourteen are caused by cancer."

Although it sounds alarming, Carson's statistic is essentially meaningless unless it's given some context, which she failed to supply. It turns out that the percentage of children dying of cancer was rising because other causes of death, such as infectious diseases, were drastically declining.

In fact, cancer rates in children have not increased, as they would have if Carson had been right that children were especially susceptible to the alleged health effects of modern chemicals. Just one rough comparison illustrates this point: In 1938 cancer killed 939 children under 14 years old out of a U.S. population of 130 million. In 1998, according to the National Cancer Institute, about 1,700 children died of cancer, out of a population of more than 280 million. In 1999 the NCI noted that "over the past 20 years, there has been relatively little change in the incidence of children diagnosed with all forms of cancer; from 13 cases per 100,000 children in 1974 to 13.2 per 100,000 children in 1995."

Clearly, if cancer incidence isn't going up, modern chemicals can't be a big factor in cancer. But this simple point is lost on Carson's heirs in the environmental movement, who base their careers on pursuing phantom risks. The truth is that both cancer mortality and incidence rates have been declining for about a decade, mostly because of a decrease in the number of cigarette smokers.

The Great Cancer Scare launched by Carson, and perpetuated by her environmentalist disciples ever since, should have been put to rest by a definitive 1996 report from the National Academy of Sciences, Carcinogens and Anticarcinogens in the Human Diet. The NAS concluded that levels of both synthetic and natural carcinogens are "so low that they are unlikely to pose an appreciable cancer risk." Worse yet from the point of view of anti-chemical crusaders, the NAS added that Mother Nature's own chemicals probably cause more cancer than anything mankind has dreamed up: "Natural components of the diet may prove to be of greater concern than synthetic components with respect to cancer risk."

Meanwhile, Carson's disciples have managed to persuade many poor countries to stop using DDT against mosquitoes. The result has been an enormous increase in the number of people dying of malaria each year. Today malaria infects between 300 million and 500 million people annually, killing as many 2.7 million of them. Anti-DDT activists who tried to have the new U.N. treaty on persistent organic pollutants totally ban DDT have stepped back recently from their ideological campaign, conceding that poor countries should be able to use DDT to control malaria-carrying mosquitoes.

So 40 years after the publication of Silent Spring, the legacy of Rachel Carson is more troubling than her admirers will acknowledge. The book did point to problems that had not been adequately addressed, such as the effects of DDT on some wildlife. And given the state of the science at the time she wrote, one might even make the case that Carson's concerns about the effects of synthetic chemicals on human health were not completely unwarranted. Along with other researchers, she was simply ignorant of the facts. But after four decades in which tens of billions of dollars have been wasted chasing imaginary risks without measurably improving American health, her intellectual descendants don't have the same excuse.