I share much of co-blogger Jonathan Adler’s skepticism about the precautionary principle. If consistently applied, the principle actually counsels against its own adoption. As usually defined by its proponents, the precautionary principle states that:
When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically.
In this context the proponent of an activity, rather than the public, should bear the burden of proof.
Incorporating the precautionary principle into public policy is itself “an activity [that] raises threats of harm to human health or the environment.” Adherence to the principle might prevent or retard the adoption of new technologies and policies that could save many lives. For example, application of the precautionary principle to prevent the use of genetically modified foods may cause mass starvation in Africa. The precautionary principle could also prevent or slow down policies that increase economic growth, which might also cost many lives. If the principle had been in force in the past, it probably would have prevented or at least greatly retarded the spread of such technologies as railroads, airplanes, and printing presses. Trains and planes pose clear threats to health. And the printing press can be used to spread dangerous ideas that promote violence and undermine the social order, thereby endangering both health and the environment.
Since it is the “proponent of an activity” that “should bear the burden of proof” under the precautionary principle, the principle counsels against its own adoption unless and until its advocates can prove that it won’t cause “harm to human health or the environment” in any of the above ways. Moreover, they must effectively address even those possible “threats” that “are not fully established scientifically.” Advocates of the principle haven’t even come close to meeting that burden of proof.
None of this means that there aren’t genuine environmental problems, some of which require regulatory solutions. It merely suggests that the precautionary principle is a poor guide to deciding how to address these and other dangers.
I discussed some other shortcomings of the precautionary principle and its application in this post.