Public Law & Legal Theory
As many treaties and statutes emphasize, some risks are distinctive in the sense that they are potentially irreversible or catastrophic; for such risks, it is sensible to take extra precautions. When a harm is irreversible, and when regulators lack information about its magnitude and likelihood, they should purchase an “option” to prevent the harm at a later date—the Irreversible Harm Precautionary Principle. This principle brings standard option theory to bear on environmental law and risk regulation. And when catastrophic outcomes are possible, it makes sense to take special precautions against the worst-case scenarios—the Catastrophic Harm Precautionary Principle. This principle is based on three foundations: an emphasis on people’s occasional failure to appreciate the expected value of truly catastrophic losses; a recognition that political actors may engage in unjustifiable delay when the costs of precautions would be incurred immediately and when the benefits would not be enjoyed until the distant future; and an understanding of the distinction between risk and uncertainty. The normative arguments are illustrated throughout with reference to the problem of global warming; other applications include injunctions in environmental cases, genetic modification of food, protection of endangered species, and terrorism.
Cass R. Sunstein, "Irreversible and Catastrophic," University of Chicago Public Law & Legal Theory Working Paper, No. 88 (2005).