In "'Better Safe Than Sorry' Usually Leaves Us Even More Sorry, And Much Less Safe" (and "Why 'Hope for the Best, Plan for the Worst' is Bad Policy" as well), I discussed the common argument, especially when it comes to issues such as environmentalism, food safety, pesticides, global warming and the like, that we should act on incomplete, or even inconclusive information, because if the worst case scenario is true, we will suffer such losses that we MUST act NOW! As I pointed out in that essay, such an argument may have a visceral appeal for some, playing into their fear or risk avoidance, and it may even sound reasonable to some, being presented at times in a bastardized version of cost-benefit analysis, however, when viewed through the lens of true cost-benefit analysis, the argument holds no water, as the proposition fails to take into account (1) the probability of the event coming to pass, by which we must adjust the severity of the consequences and (2) the costs incurred by acting to prevent the event, which must be compared to the risk adjusted threat. Instead, we are presented with simply the magnitude of the risk, and, perhaps, an estimate of the cost -- usually presented only as a "low ball" purely monetary cost -- without any thought of probability, or a true assessment of costs.
I thought of this again today, as one of the worst mistakes of the 1970s, as well as one of the most deadly blunders of the EPA, seems to continue to bear fruit, proving that, not only must we consider costs well beyond the purely financial, but must also consider the possibility that our actions may impose future costs we cannot foresee. Obviously, such costs are difficult to include in any assessment, but that is not my point. My point is, if we are to be frightened into action by the remote risk of some worst case scenario, why should we not also consider the likelihood that acting on this fear might produce equally dreadful consequences? And, that being the case, is it not better to take some time, and calmly assess both the risk and the costs, so as to minimize the potential harm on both sides of the equation, rather than be frightened into precipitate action by a doomsayer's worst case scenario?
The scenario I am discussing is the ongoing ban, and public fear of, DDT -- an action taken by the fledgling EPA, admittedly to make a show of "flexing its muscles", based on a scientific thesis that was already losing support years before the ban was enacted. However, because some people argued "where there's smoke there's fire" and "why take the risk, even if it is remote?", the EPA, seeking a popular cause to make a strong showing, banned DDT. And so, in the name of "better safe than sorry", we were denied access to one of the most effective tools against mosquito borne ailments.
So, what risk did we avoid? In truth, we will never know for sure. However, we can make a fair estimate. First, the risk of human health effects was far overblown. Studies with volunteers exposed to tremendous quantities, as well as studies of soldiers exposed to repeated, heavy spraying, showed no risk at all. And if there was no risk to such hefty doses, then what risk was likely from the low levels found persistent in soil and water?
And what of the birds? What of tales of bird's eggs having thin shells? Well, in truth, there was little evidence. Direct studies of various birds fed DDT in high doses showed a small, but statistically inconsequential, THICKENING of shells. Similarly, there is no statistical connection between bird populations and DDT use. A few studies that assessed the studies showing thinning shells argued that either the areas in question had seen new development, bringing nighttime light and noise to nesting areas, or else covered periods where nighttime temperatures were unusual for the season. Both of these have been associated with thinning shells, and suggest that DDT had no role in the supposed thinning of shells.
Similarly, the worries over "bio-accumulation"seem overblown. As with most soluble chemicals, bodies develop a level of saturation which is kept relatively constant, unless the environmental levels change. This is true whether one is a single celled organism, a plant, a herbivore or predator. The chemical simply do not accumulate up the food chain as was feared. And the few studies cited to make the argument for accumulation on the upper levels of the food chain show so many methodological errors it is difficult to take them seriously.
In short, while we will never know with certainty whether or not we averted a disaster by banning DDT, the evidence certainly suggests the risks of continued DDT use were trivial, at worst small and manageable. Nothing even hints at a major catastrophe, and certainly not one of the scope many fear mongers predicted*.
On the other hand, the costs are all too evident. Malaria, once reduced to a few thousand cases a year, is once again effecting millions per tear. So bad has the problem become that we hear constant appeals for mosquito nets, as, without the ability to use DDT, these seem the most effective means of preventing the spread of malaria. The same is true of other, similar mosquito borne ailments, from yellow fever to eastern equine encephalitis, the numbers, which declined until the late 1960s, have seen a resurgence. Of course, with better ability to treat, the fatalities are not as great as they once were, but the fact remains, the number infected is equal, or greater, in many cases than before we began using DDT. It is only the improvements of medical care -- and our physical remoteness form most of the malarial regions -- that keep us from recognizing the costs this ban imposed upon us.
Not that we do not also use pesticides. With DDT banned, we have had to turn to less effective, less persistent, and often more toxic alternatives. Where DDT seemed almost tailor-made to wipe out certain mosquito species, our substitute chemicals are much less effective, and break down much more quickly. As a result, we must spray more often, and with greater quantities**.
And then there is that cost which was impossible to predict, the one which inspired me to write today. In this case, it is Zika, a new mosquito borne ailment which is spreading rapidly and having terrible consequences. And yet, once again, we fail to recognize that our own foolishness is, at least in part, responsible for the terrible costs of this ailment. Had we not adopted the foolish "better safe than sorry" policy of banning DDT based upon unsubstantiated fears and the worst case scenarios of professional doomsayers has left us suffering in the future. All because we failed to consider that our ill considered ban might have future consequences we did not consider.
* Rachel Carson's prediction of the American robin's extinction in the 1960s for example, did not come to pass, even though DDT was not banned until many years later. Nor did the massive "die offs" of aquatic food chains, or the collapse of "biospheres" as insects were eradicated and the higher layers of animals failed to thrive. In short, despite over a decade of such predictions prior to the banning of DDT, we saw none of these fears even begin to materialize.
** To be honest, the risks of these pesticides is often overstated as well, as, for the most part, they are relatively safe or would not be used. But is is interesting to me that (1) they are being used as an alternative to the much less toxic DDT and (2) those who worry about these chemicals worried even more about a much LESS toxic chemical such as DDT.
For more discussion on DDT and environmentalism and cost-benefit analysis in general, I suggest reading the following: "...Before the Truth Has a Chance to Get Its Pants On", "Liability Law and Cost-Benefit Analysis", "Kelo, Home Schooling and Drug Laws - Inconsistent Theories of 'Social Costs'", "GMO Revisited - As Well as Hormones, Soy, Phytoestrogens, and a Host of Other Food Scares", "Salt, Transfats, DDT, Bad Science and Even Worse Law", "More Unintended Consequences", "A Passing Thought on Transfats" and "The Gadarene Swine Fallacy".