Naomi Oreskesâ€™ book about climate change deniers makes some interesting points about the pesticide DDT. Apparently, there has been a kind of campaign recently to challenge the history of the substance and its ban, with some anti-regulation groups claiming the regulation of DDT was unneccessary and caused many human deaths. They argue that if DDT use had not been regulated, malaria could have been eradicated.
Oreskes seems to rebut this argument convincingly. Critically, she points out how DDT had been stripped of its effectiveness through over-use, particularly in agriculture. She makes the point that the consequences of different sorts of DDT use for the genetics of the mosquito population can be very different. Spraying indoors exposes only a small minority of mosquitoes to the chemical, leaving most of the population isolated from it. As a consequence, there is only a small advantage for those mosquitoes that are more resistant to the poison. By contrast, widescale agricultural spraying exposes whole populations of mosquitoes to the toxin. Those who are a bit resistant to it have a huge advantage, and soon come to dominate the population. Over time, the indiscriminate use of DDT breeds mosquitoes who are troubled less and less by the toxin.
Oreskes documents how the banning of DDT took place only after its effectiveness was lost, as well as how the environmental and human health effects of the substance were sufficiently worrisome to justify the ban. She argues that the recent attempt to change the historical narrative is not about DDT itself – which nobody is seeking to reintroduce. Rather, it is intended to foster and enlarge a general sense that taking precautions to protect human health and the environment is unjustified, and that science that supports the regulation of industry and individual behaviour is ‘junk’.
A related situation that I have written about before is the abuse of antibiotics in the livestock industry. Just as the agricultural use of DDT provided ideal circumstances for insects to evolve resistance, todayâ€™s factory farms may as well have been custom designed to render our antibiotics ineffective. Crowding huge numbers of unhealthy animals close together, flooding them with chemicals to make them grow as quickly as possible, feeding them unnatural diets, and then using antibiotics to try and keep them from dying too early, is a string of compounding errors. Not only does it demonstrate considerable disregard for the welfare of the animals in question, but it demonstrates a lack of foresight when it comes to maintaining the effectiveness of our drugs and the relative manageability of the bacteria out there.
Of course, the political system tends to favour the small group of farmers that benefits from the status quo and which would suffer significantly from a change in policy, rather than the great majority of people who are incrementally harmed by the emergence of ever-more-dangerous superbugs, and the dilution of the effectiveness of the relatively small class of chemicals capable of safely killing bacteria inside human beings, without causing undue harm to the person.