Abstract

As it becomes more and more doubtful that the international community will take adequate steps to mitigate climate change, interest has grown in the possibility of engineering earth’s climate to prevent catastrophic levels of warming. Unfortunately, geoengineering schemes have the potential to create grave, unintended consequences. This paper explores the extent to which the precautionary principle (PP), which was developed as a guideline for responding to uncertainty in the policy sphere, can provide guidance for responding to the potential benefits and hazards associated with geoengineering. The paper argues that there are so many different versions of the precautionary principle and so many potential strategies for geoengineering that there cannot be any single, simple relationship between the two. Nevertheless, it is possible to identify a set of lessons that many versions of the PP suggest for those considering geoengineering proposals. Moreover, examination of the geoengineering case provides an opportunity to reflect on a range of important situations—what this paper will call self-defeating scenarios—in which most versions of the PP provide limited guidance compared to other ethical principles.