Tonight on PBS, a well-crafted hagiography in the form of a two-hour documentary detailing the life and work of environmentalist Rachel Carson will air as part of the American Experience series. Carson's 1962 book Silent Spring is widely credited for igniting the modern environmentalist movement. Trained as a marine biologist, Carson worked for many years as a publicist for the U.S. Fish and Wildlife Service, leaving after her book The Sea Around Us became a national bestseller in 1951.
Directed by Michelle Ferrari, produced by Ferrari and Rafael de la Uz, and executive produced by Mark Samels, the documentary devotes two-thirds of its time to detailing her formative years. After her father died, Carson shouldered the responsibilities of supporting her mother, her sisters, and eventually adopting the son of one her nieces who died. The documentary also delves into the tender and sustaining friendship that developed between Carson and her Southport Maine neighbor Dorothy Freeman.
The documentary culminates with the publication and the massive impact of Silent Spring. It is not an exaggeration to say that we are all still living in the intellectual and public policy world that Rachel Carson constructed in that book. "Already alarmed about the environmental damage caused by the atmospheric testing of nuclear weapons, Carson determined to alert the public to the dangers of pesticides and began the work that would define her legacy," explains the documentary press release. The film details how the U.S. public became alarmed when it learned that radioactive strontium-90 from the fallout of atmospheric tests of atomic bombs had been detected in the milk that their children were drinking. The 1954 Castle Bravo hydrogen bomb test was much more powerful than the researchers had calculated releasing a vast cloud of fallout that, among other things, doused the Lucky Dragon Japanese fishing boat downwind with highly radioactive white dust particles. The 23 fishers suffered significant radiation poisoning and one died.
Thus it was no accident that Carson opened Silent Spring with a "a fable for tomorrow" portraying an idyllic American town in which all the birds were silent and people were ill with new kinds of sickness had been dusted with a "white granular powder" that some weeks before "had fallen like snow upon the roofs and the lawns, the fields and streams." This evocative image succeeded brilliantly in alarming a good bit of the public about modern synthetic chemicals and stirred powerful reactions among policymakers in Washington, DC. And, not surprisingly, it provoked a furious series of attacks – many unfair and quite sexist - from the chemical companies and lots research scientists. For example, Monsanto tried somewhat ham-fistedly to counter Silent Spring with "The Desolate Year" detailing how crop failures and disease would spread without modern pesticides.
Time has proved that Carson was right that agricultural spraying of the popular pesticide DDT did reduce the populations of hawks and eagles by thinning their eggshells. She was also right that widespread use had resulted in increasing pesticide resistance among many targeted insect species. These findings did indicate that they should be used more judiciously.
Somewhat surprisingly, the documentary does not delve any more deeply into what science has discovered about the risks and benefits of synthetic pesticides in the 55 years since the publication of Carson's book. So what light does subsequent research shed on the claims made in Silent Spring?
As an elegant and effective rhetorician Carson understood that while some Americans might be a bit worried about the health of birds and other wildlife, what would really get their attention is cancer. She was most concerned about the long-term effects of exposures to pesticides and other synthetic chemicals, but she sought to frighten readers with anecdotes about acute exposure producing cancer with months or weeks. She tells a story about a woman "who abhorred spiders" and who sprayed her basement with DDT in mid-August. She died of acute leukemia a couple of months later. In another passage, Carson cites a man embarrassed by his roach-infested office who again sprayed DDT and who "within a short time … began to bruise and bleed." He was within a month of spraying diagnosed with aplastic anemia. Again, comparing pesticides to the contamination of milk by radioactive fallout, Carson aimed to worry parents about the possibility of their kids getting cancer.
The PBS documentary shows clips of Carson interviews aired on the CBS Reports program in the spring of 1963 with Eric Severeid. "We have to remember that the children born today are exposed to these chemicals since birth; perhaps before birth," warns Carson. Now what is going to happen to them in adult life as a result of that exposure? We simply don't know because we've never had this kind of experience." Nearly 55 years after the publication of Silent Spring we do know and, fortunately, Carson's concerns have turned out to be way overblown.
For example, in Silent Spring Carson warned, "Today, more American school children die of cancer than from any other disease [her emphasis]." That is still true today. But why had cancer emerged as the greatest killer of children in the 1950s? Not because it had significantly increased, but because far fewer were dying of the infectious diseases that had killed them in droves during earlier decades. The good news is that due to improvements in treatment the death rate from cancer for children 14 and under has fallen from 6.5 in 1969 to 2 per 100,000 now. Cancer incidence has ticked up for children under age 14 from 13 cases in 1974 to 17 cases per 100,000 now. As the American Cancer Society notes, a small percentage of cancer in children results from inherited genetic mutations, but otherwise, there are "few known risk factors for childhood cancer."
Despite activist urgent alarms, subsequent decades of research have proved that exposure to trace amounts of all sorts of synthetic chemicals are not increasing the age-adjusted incidence of cancer. In fact, the cancer incidence rate among Americans has been falling for more than two decades. According to the latest Cancer Statistics 2017 report from the American Cancer Society, the overall cancer incidence rate (2004-2013) was stable in women and declined by approximately 2% annually in men, while the cancer death rate (2005-2014) declined by about 1.5% annually in both men and women. As the American Cancer Society has noted, "Exposure to carcinogenic agents in occupational, community, and other settings is thought to account for a relatively small percentage of cancer deaths – about 4 percent from occupational exposures and 2 percent from environmental pollutants (man-made and naturally occurring)."
The documentary also includes a clip from CBS Reports featuring American Cyanamid biochemist Robert White-Stevens. "Miss Carson is concerned with every possibility of hazard and danger whereas the agricultural school has to concern itself with the probability, the likelihood of danger and assess that against utility," states White-Stevens. "If we had to investigate every possibility, we would never make any advances at all because this would require an infinite time for experimental work and we would never be finished." White-Stevens was arguing against what is now known as the precautionary principle; the idea that new technologies must be proven entirely safe before they can be deployed.
At the end of the documentary, Harvard science historian Naomi Oreskes rightly observes that Rachel Carson began a new public conversation. "It's a conversation about the pros and cons of technology; it's a conversation about the role of nature in our life, and about whether or not we make our lives better through technological innovations or whether we do damage that outweighs the benefits." I think that the benefits modern technological progress massively outweigh the risks.
Check your local PBS listings for when it airs tonight.