In reading this article about a study justifying the closing of airports (and grounding of flights) in Europe last year after the eruption of a volcano in Iceland (to avaoid problems due to the large amounts of particulate material dispersed into the atmosphere), I am reminded of the arguments concerning the large amounts of money invested in avoiding possible problems due to the “Y2K” issue in the late 1990’s. The aitport closing costs the airline industry several billion dollars, but resulted in no loss of aircarft due to the cloud from the volcanic eruption. Would any planes have crashed had this not been done? Who knows — but if past disasters have taught us anythign, it is that we must be prepared to act based on the best possible knowledge of the impact of extreme conditions (or known faults, in the case of Y2K) before a failure occurs. If engineers (and policy makers) are successful, failure will be avoided. But that will always lead to arguments over whether the investment was worth it.
This also reminds me about arguments over investment in preventative medical care, etc. One can never tell what the outcome would have been had these precautions not been taken. Yet, for financial and other reasons — including any possible negative impact of the remedy or precautions — decisions must be made based upon peer-reviewed scientific evidence, collected past experience, and use of comprehensive computational calculations, modeling and simulations. This is an expensive perscription, but perhaps the best way to avoid some disasters.