Silent Spring is a classic, a powerful broadside against synthetic pesticides. Now, more than fifty years old, the book still packs a solid roundhouse punch. With one book, one woman enlightened millions and spurred a loud outcry. One woman inspired big changes. Many of the pesticides she slammed have been banned or highly restricted.
Following World War II, Americans had big heads. We had won the war, invented a terrible new weapon, our economy was booming, and life was great! We succeeded at whatever we tried. We were giddy with euphoria. Then, Rachel Carson rolled a hand grenade into our dining rooms. Suddenly, Sunday dinners at grandma’s looked far less delicious. What were we eating? Would it kill us?
During the war, researchers working on chemical warfare agents discovered substances that were highly toxic to insects. After the war, greedy minds became fascinated by these super-poisons, and visions of big profits danced in their heads. Synthetic pesticides were toxic to morals, ethics, and foresight. And so, a new industry was born, and the production of pesticides increased five-fold between 1947 and 1960.
To control the elm bark beetles that caused Dutch elm disease, two to five pounds of DDT were sprayed on elm trees. This killed the natural predators of the beetles, as well as 90 species of birds, and assorted mammals. Worms ate the poison leaves, and the robins that ate the poison worms quit reproducing. Elms kept dying. More elms survived in places not sprayed.
To control gypsy moths, a million acres a year were sprayed with DDT. Sprayers were paid by the gallon, not the acre, so some places were sprayed multiple times. Bees died. Cows ate DDT grass and produced DDT milk that was consumed by DDT humans. Regulators did not block the sale of poison milk. At the end of the expensive project, the gypsy moths returned.
To control fire ants, millions of acres were sprayed with two new poisons: dieldrin and heptachlor, which were far more toxic than DDT. Newborn calves died after their first drink of milk. Piglets were born dead. Opossums, armadillos, raccoons, quail, songbirds, turkeys, livestock, poultry, and pets died. In the end, there were more ants in Florida than before.
We know little about what these toxins do to the complex microorganisms in healthy topsoil. Many of them interfere with nitrogen-fixing bacteria, which provide an essential nutrient for all living things. Some organisms are wiped out, leading to explosions of other organisms. The chemicals persist in the soil for years, and build up with each new application. Soil beneath an apple tree can contain 113 pounds (51 kg) of DDT. Old-fashioned arsenic pesticides keep the soil toxic forever.
Yes, it’s a bummer that all spawning salmon died when New Brunswick’s Miramichi River got sprayed with DDT, while the terrible spruce budworms laughed at the embarrassed entomologists. When Ontario sprayed to kill blackflies, they wiped out blackfly predators, enabling the fly population to explode 17-fold. The same thing happened in Florida, where large areas in coastal regions are now uninhabitable because of hordes of pesticide-resistant mosquitoes.
“Resistant” is a keyword in this comedy of errors. Big Mama Nature routinely produces organisms that are resistant to insecticides, herbicides, fungicides, antibiotics, and antivirals. We can throw one poison after another at life, and life will become resistant to it. Winning the war on life is impossible. Resistance can develop in as little as two months. The average time is three years. Insects are reproductive champions, and can promptly refill the land with resistant offspring. The breeding process in humans is much slower, so it will take us thousands of years to become resistant to pesticides.
Silent Spring delivered two powerful messages. It alerted us to the nightmare world of pesticides. It also turned big floodlights on the incredible incompetence of our experts and regulators. In 1960, almost everyone was blissfully ignorant about the toxic chemicals in their lives. In those days, most folks still trusted their elected officials. They trusted the experts who told them that DDT was harmless, and chlordane was a wonder of scientific genius. Today, for good reason, we automatically doubt any statements made by leaders or experts because they, too often, have little or no relationship to the full truth.
Carson did not believe that the use of pesticides should be banned entirely, but she did recommend that we shift toward less toxic alternatives, like pyrethins and Bacillus thuringiensis (Bt). Not surprisingly, malarial mosquitos are becoming resistant to bed nets treated with pyrethin-based insecticides, and many crop pests are now resistant to Bt.
She was fascinated by research in sterilizing male bugs, so that female bugs would not be able to tell the studs from the duds. Chemo-sterilants were used to render millions of houseflies impotent. Male gypsy moths found their lovers via sexy scents. Researchers sprayed this scent all over the place, and were delighted to observe the flying lads falling deeply in love with wood chips that smelled like hot babes. Ultrasonic sounds could be used to kill blowflies, mealworms, and yellow fever mosquitoes.
About half of the insects called pests are immigrants from foreign lands. Here, they were not controlled by their natural predators from the old country. Carson recommended importing the predators and parasites of notorious immigrant pests. Moving organisms from one region to another is a mistake that has often led to unintended disasters, like the rabbits of Australia, the potatoes of Ireland, smallpox, and so on. She thought that it was OK for humans to try to sit in the ecosystem’s driver’s seat.
Carson was fighting breast cancer as she finished her book, and she died in 1964, two years after it was published. If she had lived longer, I think she would have recognized the serious shortcomings of the anthropocentric worldview of her era. Living like the masters of the planet has been a reliable recipe for countless catastrophes, and it’s the core reason why seven billion people are standing on very thin ice today.
Ecological thinking is the antidote. Forget control — adapt! Carson was intrigued by the brilliant rascal Paul Shepard, who could have exorcised her anthropocentric demons, had she lived longer. She quoted Shepard, who summed it up nicely: “Why should we tolerate a diet of weak poisons, a home in insipid surroundings, a circle of acquaintances who are not quite our enemies, the noise of motors with just enough relief to prevent insanity? Why would want to live in a world which is just not quite fatal?”
PS: Locust is the story of how humans, for once, actually succeeded in driving a major crop-destroying insect pest into extinction — unintentionally — by simply living like civilized people.
Carson, Rachel, Silent Spring — Fortieth Anniversary Edition, Houghton Mifflin Company, New York, 2002.