Thursday, September 21, 2006

Truth wins out, but slowly...

When Rachel Carson published "Silent Spring" back in my youth, she sparked the beginning of the modern environmental movement.

Now some 40 years later, the main target of her book, DDT is being re-evalauted to combat the continued scourge of malaria in Africa. In fact, spraying will re-commence in 2007.
The World Health Organization on Friday called on more developing countries, particularly in Africa, to begin spraying the controversial pesticide DDT to fight malaria. The difference: DDT, longed banned in the United States because of environmental damage, is no longer sprayed outdoors. Instead it's used to coat the inside walls of mud huts or other dwellings and kill mosquitoes waiting to bite families as they sleep. A small number of malaria-plagued countries already use DDT, backed by a 2001 United Nations treaty that set out strict rules to prevent environmental contamination. But the influential WHO's long-awaited announcement makes clear that it will push indoor spraying with a number of insecticides and that DDT will be a top choice because when used properly it's safe, effective and cheap. "We must take a position based on the science and the data," said Dr. Arata Kochi, the WHO's malaria chief. "One of the best tools we have against malaria is indoor residual house spraying. Of the dozen insecticides WHO has approved as safe for house spraying, the most effective is DDT." "It's a big change," said biologist Amir Attaran of Canada's University of Ottawa, who has long pushed for the guidelines and described a recent draft. "There has been a lot of resistance to using insecticides to control malaria, and one insecticide especially. ... That will have to be re-evaluated by a lot of people." [More]

Carson's masterwork brought to the public's attention the idea of humankind as the destroyer of nature, whereas before nature was seen as something needing "taming" with our technology. While her message resonated with both the social and technological unease in much of the West, her arguments were fairly weak:

Carson was also an effective popularizer of the idea that children were especially vulnerable to the carcinogenic effects of synthetic chemicals. "The situation with respect to children is even more deeply disturbing," she wrote. "A quarter century ago, cancer in children was considered a medical rarity. Today, more American school children die of cancer than from any other disease [her emphasis]." In support of this claim, Carson reported that "twelve per cent of all deaths in children between the ages of one and fourteen are caused by cancer."

Although it sounds alarming, Carson’s statistic is essentially meaningless unless it’s given some context, which she failed to supply. It turns out that the percentage of children dying of cancer was rising because other causes of death, such as infectious diseases, were drastically declining.

In fact, cancer rates in children have not increased, as they would have if Carson had been right that children were especially susceptible to the alleged health effects of modern chemicals. Just one rough comparison illustrates this point: In 1938 cancer killed 939 children under 14 years old out of a U.S. population of 130 million. In 1998, according to the National Cancer Institute, about 1,700 children died of cancer, out of a population of more than 280 million. In 1999 the NCI noted that "over the past 20 years, there has been relatively little change in the incidence of children diagnosed with all forms of cancer; from 13 cases per 100,000 children in 1974 to 13.2 per 100,000 children in 1995." [More]

Both views are likely flawed, but oddly we seem to be drifting farther from embracing compromise solutions. In order to prove our passion we embrace black/white, good/evil postures, and treat even-handedness as weakness.

The DDT episode should serve as a lesson, at least in matters of technology. Perhaps the bravest thing, and the most productive is to find a workable compromise.

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