Unintended Consequences

The Lessons of Rachel Carson's 'Silent Spring.'

 Like many others, we maintain a bird feeder in our yard, keeping it stocked during the cold-weather months as well as in the summer. The feeder draws a diverse clientele—a couple of cardinals, an occasional blue jay, mourning doves, and black birds. But, by far the largest group to show up is the house sparrows.

   These birds, despite being small, are known for their aggressive and, at times, ruthless behavior. These traits have aided them in staking out territory. Further enhancing their cause is an ability to utilize human dwellings and outbuildings for nesting purposes. They’re also known to confiscate the bird houses people have put up, even killing the young of other species that have already taken residence in those houses.

   I have wondered as I watch the house sparrows flock to our feeder if, in our indiscriminate generosity, we’ve made it easier for them to survive and proliferate by providing them regular substance; an advantage they’ve used to either drive away or injure other birds.

   If so, then it falls under the heading of ‘unintended consequences’.

   UNINTENDED CONSEQUENCES was certainly among the lessons that Rachel Carson offered in her landmark book Silent Spring. Published in 1962, Carson used it to make the case that both overuse and misuse of pesticides, in particular DDT, were causing harmful and even deadly side effects beyond the intended target. Using scientific and medical studies, she outlined how these chemical sprays and powders—spread on farm fields, forests and swales, city parks and residential lawns, as well as in marshes and along the edges of rivers and lakes—were adversely affecting birds, fish, and other small wildlife.

   While the target of these pesticides—mosquitoes, weevils, worms, an array of other bugs, and a host of unruly weeds—were seen as detrimental to mankind, either in spreading diseases or curtailing the quality and quantity of agricultural production, the chemicals were causing collateral damage. Other insects, small creatures, and vegetables were also being destroyed.

   But, as Carson sought to point out, the more lethal outcome came over time, with the residue accumulating in the soil and water and, thus, getting into the eco-system. These pests and undesirable weeds were the food source for several of these smaller creatures. And the chemicals lingered where applied, or washed into the waterways or onto adjacent land.

   The residue would build up in the tissues of fish, birds, amphibians, and small animals, thus contaminating the food source for creatures further up the food chain. Man, she sought to point out, was not immune from this domino effect.

  One of the side effects, according to Carson, was a decrease in the reproduction success of these critters. In the case of birds, the egg shells became more fragile, resulting in fewer fledglings.

  Carson also warned that using too much of these pesticides, and doing so in a haphazard and widespread manner, made them less and less effective. Nature, as she pointed out and we have come to better understand, has a survival strategy. While a spray might kill off nearly all of a certain undesirable insect or weed, there nearly always appear to be a few survivors. They have some trait or habit that’s a little different from the majority of their kind that keeps them alive. When two these survivors reproduce, the trait or habit is passed on and, all too soon, a “super” pest has replaced the former one.

   The same evolution has resulted in various germs becoming resistant to our antibiotics and cleansers; ones we thought we could control.

     A few years ago, PBS aired a two-hour special, recounting Rachel Carson’s life and legacy. The narrators noted that a push-back to  Silent Spring came swiftly from the chemical companies and the agribusinesses that sold these pesticides.

  An effort to discredit both Carson and her findings was part of their strategy.

    The documentary noted that many of the scientists who worked for these firms were both critical and dismissive of her as an authority with any standing and the work she had presented. She was, after all, only a marine biologist with the U.S. Fish & Wildlife Service.

  That’s, perhaps, an understandable reaction. These bright minds were creating a brave new world with products that helped prevent the spread of deadly diseases like malaria, along with increasing the supply of food.  The possibility that there might be dire consequences in this march of progress was not a welcome consideration.

   Also suggesting, as Carson did, that a large, well-heeled industry was “spreading disinformation” about the harmful side effects and that public officials were not exercising due diligence in their oversight seemed to have poked a hornet’s nest of reaction

  Carson said it was not her contention that chemical pesticides never be used, but rather that a more judicious and cautious approach be taken and the situation be monitored. She also championed the idea of using more natural means of pest control. With time, that’s pretty much what’s happened in agriculture. Farmers have found it more cost effective to be selective in their applications of the different insecticides and herbicides, and have taken the same approach with fertilizers.

    CARSON DID NOT LIVE LONG AFTER the publication of her book, dying in 1964 at age 56. Her legacy would be the growing environmental movement, including the creation of the U.S. Dept. of Environmental Protection in 1970 during the Nixon Administration.

   But part of that legacy is the push-back. The efforts to discredit her and her work have continued, off and on, over the past half-century.

   Her effectiveness with the book came, in part, to being a good writer, offering a compelling narrative, providing scientific information to bolster her claims, and, maybe most important of all, presenting an argument that made sense to a lot of people.

  The book fit into growing concerns over the pollution of rivers and lakes. People could see the ill effects of industries dumping their wastes into nearby rivers and lakes or storing it in holding ponds where the contaminants leeched into the groundwater. They also understood the problem of municipalities discharging raw sewage into the waterways.

  The growing concern extended to air pollution and the health problems and environmental harm it was causing. Terms like smog and acid rain became part of the nation’s vocabulary. People could see the dark plumes coming from the smoke stacks of factories and power plants, the exhaust fumes from thousands of vehicles, and make the connection to respiratory ailments and wilted plant life.

  Here in Michigan, during the 1970’s, we had PBB, a fire retardant put accidently into cattle feed, causing problems for livestock and presenting a threat to human health due to it getting into the food chain. The after effects are still with us over forty years later, evident in the label that warns us not to eat too many fish, particularly salmon, due to this contaminant being stored in their fatty deposits.

    We live in a world of trade-offs, measuring the good and bad, the safe course and the less certain one, the benefits and the ill effects. Nothing is foolproof. This is true with the chemicals used in public health and agricultural production. There are pros and cons that need to be weighed. It is not necessarily ‘either-or’ or “I’m right and you’re wrong.”

   But identifiable (or potential) threats to human health certainly demand consideration and a remedy of prevention or correction. Such concerns should not be dismissed in a cavalier fashion, tossed aside in favor of current expediency. And, the consideration and response should not be limited to only human affairs. The impact these dangers might pose or do pose to other of nature’s creatures and to the habitat vital for their survival ought to likewise be part of the measurement.

    Rachel Carson used the metaphor, but also the potential reality, of a ‘silent spring’ as the title and theme of her book. With words and facts, she painted the image of a landscape devoid of nature’s music. Her work succeeded because there was evidence of the image already in existence.

   I’ve read where a host of creatures, large and small, are facing extinction. Unlike the house sparrow, they have not adapted well to human habitations and activities or else are the victims of changing ecosystems where other species are more aggressive or better equipped to survive.

There are the emerging challenges of a climate change, with warming temperatures apparently triggering drastic weather patterns, but of greater alarm is the altering of the natural landscape. There are pressures as well from a growing human population, with development and settlement occurring in previously lightly inhabited areas of the world.

   The polar bears in the Arctic Ocean, with a melting Arctic ice cap, appear to be in trouble. Also, under duress are the Bengal Tiger in India and the gorillas and giraffes of Africa; their numbers growing fewer and fewer as their respective habitats shrink in size.   Closer to home, frog populations in Michigan have decreased enough to cause alarm—mirroring a downward trend in other locales.

    The loss of these and other familiar creatures will probably not occur in our lifetime, but without a change in current practices or a helping hand, if the trajectory remains on course, a future generation might no longer see them except in a zoo or man-made natural preserve, or in a photograph or on film.

Or worst yet, they’ll join that large-scale extinction now occurring. Their unique presence lost. Their song ended, with only silence remaining.

Steve Horton is a mid-Michigan journalist and editor-publisher of the ‘Fowlerville News & Views.’