When I was a graduate student at the University of Kansas, the pesticide DDT was very much on my mind. My assistantship in 1953 involved research on the evolution of DDT-resistance in fruit flies. It quickly became clear to all of us in this research group that the broadcast use of pesticides was a losing and dangerous game. When I attempted to raise butterflies in New Jersey in the 1940s, bringing food plants in from nature usually resulted in the caterpillars dying. In those days, widespread spraying of DDT to control mosquitoes coated much of the countryside with poison. In the lab it was easy to use selection to make flies impervious to DDT in some 10 generations, or, in contrast, so susceptible that they would drop dead at a whisper of that “miracle” chemical’s name. Evolution of resistance tended to make continuous use of any pesticide inefficient. The usual response of the chemical industry was to recommend increasing the dose or to substitute more toxic compounds, making pest control even more expensive and dangerous.

That was well understood by evolutionists early on, but it took a marine biologist and talented writer, Rachel Carson, to bring the pesticide problem to public attention and, incidentally, to launch the modern environmental movement. Silent Spring, published in September, 1962, was a brilliant book, but also one that appeared when the time clearly was ripe. The public seemingly had been primed by publicity about radioactive fallout, fears of pesticide residues on cranberries and the thalidomide scandal, the latter enhanced by pictures of infants born with distorted limbs. Carson suffered from the drawbacks of being a female scientist before science’s gender gap began to dissolve, and from lacking a PhD and a professorial position. Despite those “handicaps,” she had the science about as right as it could be at the time.

Carson was subject to a storm of vicious attacks by the combined public-relations machines of the chemical industry and agribusiness, and even from scientists in the industry and entomology departments of some universities. Typical was the much quoted statement of Professor Robert H. White-Stevens, a poultry scientist of Rutgers University: “If man were to follow the teachings of Miss Carson, we would return to the Dark Ages, and the insects and diseases and vermin would once again inherit the earth.” The assault began even before Silent Spring was published. A public-relations campaign against Carson and trumpeting the safety of pesticides was bankrolled by the National Agricultural Chemical Association (NACA). Virtually all of the attacks were without merit. Carson withstood them all, even though she was struggling with metastatic cancer. I met her once only briefly, and then she was gone.

Rachel Carson’s legacy looms huge today. Many people have the impression that climate disruption is the worst environmental problem humanity faces, and indeed, its consequences may be catastrophic. But the spread of toxic chemicals from pole to pole may be the dark horse in the race. Carson may have started environmentalism by illuminating exactly the right issue. This is especially the case as recent research has shown that many synthetic chemicals, called endocrine-disrupting compounds, may do nasty things to you at high doses but can have different harmful effects at very low doses. These low-dose effects can increase the probabilities of altered sex determination, behavioral changes, developing cancers and more.

A mass of evidence should alert humanity to the risks of toxifying Earth from pole to pole with synthetic chemicals. For instance, Tyrone Hayes of the University of California, Berkeley, has suffered Carson-like abuse by flacks for the chemical industry for demonstrating nasty low-dose impacts of the near-ubiquitous herbicide atrazine in both the laboratory and in nature. Atrazine is manufactured by Syngenta, which has bankrolled a multimillion-dollar campaign hiring pundits to lie about atrazine and besmirch Hayes. The campaign resembles that of the well-funded fossil-fuel industry assault on climate disruption and also the tobacco industry’s perpetual storm of lies about the safety of smoking. Hayes has been, as was Rachel Carson, scientifically vindicated, and like Carson, is one of my heroes.