DR. DICKSON DESPOMMIER spent thirty-eight years as a professor of microbiology and public health in environmental health sciences at Columbia, where he won the Best Teacher award six times. In 2003, he was awarded the American Medical Student Association Golden Apple Award for teaching. He has addressed audiences at leading universities including Harvard and MIT, and he has also been invited to speak at the United Nations. In addition, he has been asked by governments of China, India, Mexico, Jordan, Brazil, Canada, and Korea to work on environmental problems. Despommier lives in Fort Lee, New Jersey.
Unintended Consequences
9/19/2011 5:46:14 PM

Weeds (wild plant life) are the farmer’s public enemy number one. Weeds invade farms and eat up the nutrients in fertilizers and suck up the water from irrigation schemes, compromising yields of corn, soybeans, potatoes, and our other cash crops, too. As the result, profits go down and the farmer pulls his hair out wondering what to do next.  Since the invention of agriculture, farmers had no one to turn to for help. That is, up until 1960s. Then along came the agricultural chemical industry and the picture changed, almost overnight. Herbicides galore (mostly glyphosate and related compounds) rolled out of the R&D labs and onto the tilled land. Yields went up and so did profits. All this change was just too good. Like anything that is too good to be true, it usually is, especially in the long run. Everyone forgot about (or never knew about, or ignored) the fundamental concept of evolution, and kept on spraying. As year after year rolled by, it was discovered that more and more herbicide was needed to do the same job as compared to the first time they were employed. The weeds were winning back the farm, and winning big time. It became apparent that this approach could not go on without major changes in weed management strategies.

In 1970, there were no wild plant species known to be resistant to glyphosate. By 2010, nearly 350 different species of wild plants had become resistant (Science News, July 2, 2011). Weeds were not going to sit there and take it, were they? Of course not. How did this unforeseen consequence of herbicide use happen? It’s a fundamental trait of all living things that random mutations occur at a rather predictable rate. Eventually, given the right situation, it is inevitable that there will be a mutant plant that can withstand increased levels of any given herbicide. They will then replace all the ones that were killed off, and thus the farmer finds himself back at square one. (Our pathogenic microbes have done the same thing regarding the use of antibiotics.) Using higher doses of herbicides the next year solved the weed problem, but only temporarily, and so it went until the weeds were at the same level of resistance as the cash crops. Humans are gifted in creating new problems in attempting to solve old ones. Unintended consequences is now a stock phrase aimed at the introduction of new technologies, no matter what the technology in question.

So what has been the agrochemical industry’s response to weed resistance to herbicides? Answer: genetic modification of crops to resist higher and higher levels of glyphosate. Hmm..., that sounds like the old paradigm. Eventually, the weeds will catch on to this new wrinkle too, and the rest is, well, you guessed it. And that’s not all. Do we know what will happen to all that herbicide when it rains? Sure. It ends up in our estuaries, altering their ecological characteristics beyond recognition. There are ample studies already published on this aspect, and fish tend to be the most sensitive indicator group to the negative effects glyphosate can have on wildlife (e.g., birth defects, endocrine disruption, adverse effects on gene expression). And do we know for sure whether or not it is safe for us to eat produce containing higher levels of herbicides? At the current levels of exposure, glyphosate appears to have caused no detectable increases in certain human diseases (cancers, respiratory distress syndromes, etc.). But what about significantly increased exposure levels? Those “studies” have been done yet. I for one, do not want the consumer public to be the “guinea pig” for that data. We have had enough historical experience with uncontrolled levels of agrochemicals (DDT, malathione, atrazine, etc.) to predict that nothing sustainable will come from the use of higher and higher levels of anything, be it pesticides, herbicides or fertilizers. Did I mention atrazine? This particular herbicide has caused more havoc with wildlife (particularly with amphibians) than any other endocrine disruptor. So much so, that its use is now banned throughout Europe. But we still allow its use here in the U.S.. Why? “More studies are needed. “Really? Well, no, but…

So, what can we do? I favor growing most of our plant crops indoors, eliminating completely the use of herbicides and pesticides. No more agricultural runoff. Year-round crop production. No more food miles. Healthy produce available next door to where we live, in our cities. What’s not to like?

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