Wednesday, October 21, 2009

Silent Spring: A Summary

Like any good tree hugger, I decided over the summer that I needed to read Silent Spring, Rachel Carson's "explosive bestseller" about the devastating effects of the chemical pesticide programs used during the 1950s and 1960s. I hear it referenced so often that I assume it's mandatory reading for entomologists, biologists, ecologists, and environmentalists alike. So I picked up a musty, crumbling paperback copy in a used book store one day and dove right in. I motored through the first couple of brief chapters pretty quickly, intrigued by Carson's answer to her own rhetorical question:

"How could intelligent beings seek to control a few unwanted species by a method that contaminated the entire environment and brought the threat of disease and even death to their own kind? Yet this is precisely what we have done. We have done it, moreover, for reasons that collapse the moment we examine them." (p. 20)

After that, however, things began to get very technical, very quickly. The book is structured as a commentary on a number of case studies done during the height of the indiscriminate chemical spraying era, from the late 1940s up to the early 1960s (when the book was published). Even though the jargon is kept to a minimum and most of the data is presented in layman's terms, it is a tedious and laborious read and I couldn't mentally process more than ten pages at a time. I aimed to get through one chapter per sitting, but with so much data crammed onto each water stained page, not even the chapters' blatantly incendiary titles (such as "Elixirs of Death", "Needless Havoc", and "No Birds Sing") could help me to maintain my focus.

As I slogged through the meaty middle chapters, I began to get an eerie feeling; it was both a sense of foreboding and deja vu. In case study after innumerable case study, while the locations, pests, and sometimes even the chemicals changed, the inevitably disastrous result was almost always the same.

When DDD was sprayed at Clear Lake in California to kill the gnats, the swan grebes died. When the hop growers of Washington and Idaho sprayed heptachlor to kill the strawberry root weevil, their crops died and the land remained unusable for years. When the U.S. Department of Agriculture sprayed dieldrin over Iroquois County, Illinois, to "eradicate" the Japanese beetle, the song birds of the region were wiped out within a matter of days. When DDT was sprayed in East Lansing to kill the gypsy moth and prevent Dutch Elm disease, the robins died. The list goes on and on, but the message is clear: saturating the country with chemical pesticides is bad... very bad. Got it.

Scientists came to discover that these poisons were stored in higher and higher concentrations as it worked its way up through the animals in the food chain. The initial spraying might not have killed a bug, for example, but it probably sickened an earthworm or a fish that ate several bugs, and in turn almost instantly killed a bird that ate several earthworms or fish. The birds that didn't die instantly were either rendered infertile or endured a long, drawn-out illness before the twitching and agonizingly painful convulsions set in that, after much suffering, ultimately killed them. And-- perhaps worst of all-- the programs didn't even work long-term.

What these short-sighted chemists and government officials failed to realize was that it's nearly impossible to eradicate a single species of pesky insect; those that survived not only reproduced at a much faster rate than their natural predators, but they became resistant to the pesticides more quickly as well, rendering subsequent sprayings ineffective. Without a healthy bird population to keep these insect populations in check, the pests' numbers can exceed pre-spraying levels in a matter of years (and sometimes months!) As Carson explains:

By their very nature chemical controls are self-defeating, for they have been devised and applied without taking into account the complex biological systems against which they have been blindly hurled ... (p. 218)

She continues:

"The really effective control of insects is that applied by nature, not by man. Populations are kept in check by something the ecologists call the resistance of the environment: The amount of food available, conditions of weather and climate, the presence of competing or predatory species, are all critically important ... [The second neglected fact it] the truly explosive power of a species to reproduce once the resistance of the environment has been weakened ... (p. 218)

Thankfully, the sprayings eventually stopped, but not before our soil and groundwater was heavily contaminated. I know many of these same pesticides are still in use today, albeit in much smaller concentrations. Still, the best way to fight a force of nature is still with nature itself. For in her final paragraph, Carson issues a harsh admonishment, warning that:

"The 'control of nature' is a phrase conceived in arrogance, born of the Neanderthal age of biology and philosophy, when it was supposed that nature exists for the convenience of man ... It is our alarming misfortune that so primitive a science has armed itself with the most modern and terrible weapons, and that in turning them against the insects it has also turned them against the [E]arth."

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