Merchants of Doubt: How a Handful of Scientists Obscured the Truth on Issues from Tobacco Smoke to Global Warming

Chapter 7, in part, focuses on Rachel Carson:

In Silent Spring…Carson explained how pesticides were accumulating in the food chain, damaging the environment, and threatening even the symbol of American freedom: the bald eagle. Although the pesticide industry tried to paint her as a hysterical female, her work was affirmed by the President’s Science Advisory Committee, and in 1972, the EPA concluded that scientific evidence was sufficient to warrant the banning of the pesticide DDT in America (216).

However, DDT was permitted to be sold to the World Health Organization to help stop malaria in Africa by killing mosquitos. 

In 2007, conservative and libertarian think tanks labelled Carson a murderer because she generated hysteria over DDT which led to millions of people dying from malaria as well as other articles supporting the use of DDT:

In the demonizing of Rachel Carson, free marketeers realized that if you could convince people that an example of successful government regulation wasn’t, in fact, successful—that it was actually a mistake—you could strengthen the argument against regulation in general (217).

“Silent Spring and the President’s Science Advisory Committee”

DDT was created in 1873 but started being widely used in 1940, when it was discovered it killed many pests, including mosquitos and lice responsible for diseases such as malaria and typhus. It could be sprayed directly onto people, including soldiers in WWII, or from planes, making it inexpensive and less toxic than arsenic. Although people believed DDT to be safe, biologists working at the US Fish and Wildlife Service, including Rachel Carson, noticed DDT’s deleterious effects on birds and fish, hypothesizing that it was probably bad for humans as well. Carson was already known within the scientific community from an earlier book, and Silent Spring(1962)was serialized in the New Yorker, giving instant media attention to the fact that DDT and other common pesticides once thought to be safe were shown—through anecdotal and systematic scientific evidence—to do great harm. DDT killed smaller animals, from birds to squirrels and even household pets, and didn’t break down in the environment, instead accumulating via the food chain and unbalancing ecosystems. The pesticide industry attacked Carson for being hysterical and emotional, claiming her science was anecdotal, unproven, inadequate, and wrong, even though many scientists agreed with her.

President Kennedy asked PSAC to study the relatively unstudied DDT, “to contrast the obvious, rapid benefits of pesticide use in disease control and food production with the subtle, long-term, poorly understood risks to humans and nature” (221). There were many scientific uncertainties and few existing clinical studies on long-term effects but even so, PSAC believed it was time to limit pesticide use as there was clear evidence of damage to wildlife even when used correctly. PSAC also advised the creation of a comprehensive program for controlling environmental pollution, which Congress would do with the Clean Air and Water Acts and the establishment of several agencies, including the EPA in 1970. After a decade’s worth of scientific assessments, the EPA banned DDT in 1972.

The Kennedy PSAC report maintained scientific uncertainty regarding the toxicity of pesticides while calling for immediate action and further study, placing the burden of proof on those who argued that pesticides were safe.

However, critics blamed Carson, saying that malaria would have been eradicated with the use of pesticides and the DDT ban lacked scientific evidence. These attacks, including likening Carson to Hitler or Stalin, were echoed in mainstream media.

However, history tells us that these attacks are wrong, as “malaria eradication failed in less developed nations because spraying alone didn’t work” (224) and mosquitoes developed resistance to the pesticides, leading to an increase in use of DDT. This excess use in agriculture is one of the main reasons DDT failed to control disease, as it ensured only the bugs resistant to the pesticide survived, which then passed on their genes to their offspring, which Carson discussed in her book.

In the 1930s, American malaria was brought under control via drainage, removal of breeding sites, and use of pesticides other than DDT, which was the same tactic that had been used earlier in the Panama Canal to control yellow fever and malaria: “DDT alone did not eradicate insect-borne diseases, and those diseases have been controlled in places with little or no use of DDT” (226).

When the EPA banned DDT, it did not (and could not) prohibit the sale of DDT to other countries. Most of Carson’s critics believed that pesticides were integral to the productivity of modern agriculture and would lead to solving world hunger (despite the fact that most social scientists believe the problem is unequal distribution, not a food shortage). Critics also misused some of the critiques of people who agreed on a scientific level, but not on an ideological one, using ideological differences to imply scientific differences.

With little evidence to demonstrate human deaths resultant from DDT, Carson used the demonstrated harm to ecosystems to infer that DDT could also be harmful to humans. But DDT was not banned because it was toxic to humans; rather it was banned because it was harmful to the environment, claims which were affirmed by PSAC and the EPA and other studies: “DDT kills birds, fish, and beneficial insects, and continues to do so long after spraying has stopped” (228).

Although Carson did not directly link DDT to cancer, Carson also didn’t just write about DDT; she wrote about many pesticides, and many pesticides have since been proven to be carcinogenic. Recently, a scientific review emerged asserting that DDT harms reproductive health and is correlated to infant and childhood mortality. Similarly, later studies recognized the flaws in earlier studies which failed to link breast cancer to DDT use, arguing that women exposed to DDT as children or teenagers (and not as adults) increases the risk fivefold of these women developing breast cancer later in life: “There is no scientific evidence to support the claim that millions of lives have been needlessly lost, and there is substantial scientific evidence that a good deal of harm—both to humans and the other species we share this planet with—has been avoided” (229).

The revisionist history of DDT came long after the science was settled and most scientists had formed a consensus, making it an argument about free market ideology, not science (or even history).

“Denial as Political Strategy”

Carson was one of the reasons behind the surge of environmentalism in the 60s and 70s: “If Carson was wrong [then] the contemporary environmental movement could be shown to have been based on a fallacy, and the need for government intervention in the marketplace would be refuted” (230). Critics cherry-picked historical and scientific facts, especially ignoring the resistance mosquitoes began displaying to DDT as early as 1958 and its ineffectiveness by the late 1960s, despite more frequent use over larger areas. This led nations still affected by malaria to switch to alternative pesticides; it had nothing to do with the American ban on DDT, which didn’t (and couldn’t) affect other nations, anyway.

Regardless, critics still claimed that the US ban on DDT caused millions of preventable deaths, which many labeled a genocide. These critics used the terminology of the tobacco industry, junk science, and for a while were indirectly funded by the tobacco industry as well. The attacks were distributed to politicians, journalists, and businessmen as well as parroted via conservative media by the likes of Rush Limbaugh and conservative novelists such as Michael Crichton. Philip Morris especially had its hands in many NGO cookie baskets, giving tax-deductible money to a variety of think-tanks and organizations that seemingly had little to do with the tobacco industry, yet repeatedly focused on the importance of individual liberties and lack of regulation, which aligned with the tobacco industry’s goals.

“The Orwellian Problem”

“The network of right-wing foundations, the corporations that fund them, and the journalists who echo their claims have created a tremendous problem for American science” (236). Ironically, George Orwell was seen as one of the heroes of the anti-Communist political right wing, a novelist who urged against oppressive government, control of history, the destruction of inconvenient facts, and the language to politically constrain thought. Conservative groups and media attempted to do exactly what Orwell cautioned against, obfuscating inconvenient aspects of history and science: “Lately science has shown us that contemporary industrial civilization is not sustainable. Maintaining our standard of living will require finding new ways to produce our energy and less ecologically damaging ways to produce our food” (237).