Catastrophe aversion: social attitudes towards common fates

In light of climate change and other existential threats, policy commentators sometimes suggest that societyshould be more concerned about catastrophes. This document reflects on what is, or should be, society’s attitudetoward such low-probability, high-impact events. The question underlying this analysis is how society considers :

• a major accident that leads to a large number of deaths ;
• a large number of small accidents that each kill one person

where the two situations lead to the same total number of deaths.

We first explain how catastrophic risk can be conceived of as a spread in the distribution of losses, or a “morerisky” distribution of risks. We then review studies from decision sciences, psychology, and behavioral economicsthat elicit people’s attitudes toward various social risks. This literature review finds more evidence against thanin favor of catastrophe aversion.

We address a number of possible behavioral explanations for these observations, then turn to social choice theoryto examine how various social welfare functions handle catastrophic risk. We explain why catastrophe aversionmay be in conflict with equity concerns and other-regarding preferences. Finally, we discuss current approachesto evaluate and regulate catastrophic risk, with a discussion of how it could be integrated into a benefit-costanalysis framework.