Astronomical Odds

Addresses the cosmic impact hazard (the threat to the Earth posed by asteroids and comets) as an extreme example of a low-probability, high-consequence policy problem. This analysis presents a comprehensive framework for dealing with the technical and societal uncertainties surrounding the impact hazard. It reviews the physical nature of the threat and both the history and mechanisms of society’s response to the hazard, dwelling on the social costs of false positives. The author constructs an illustrative cost-benefit model on the foundations of prior work, with parameters of social response added and then varied to assess the robustness of a proposed policy intervention: social reassurance by means of a demonstrated mitigation capability. He concludes by noting that a common flaw of prior analysis is to give lip service to “low probability” and to focus instead on “high consequence”; that there is frequent confusion between ex ante and ex post perspectives; that uncertain costs are often treated as nonexistent costs; and that warning is a social function, not a technical function, and those who issue warnings of a given hazard should not stand to benefit from those warnings.