The need for nonuniform risk acceptability across climate change scenarios.

Climate change risk assessment studies focus on identifying and analyzing different risks considering several climate change scenarios and on evaluating the cost-effectiveness of different adaptation measures. However, risk acceptability is often not reflected on in the context of climate change risk studies. Noting that the different climate change scenarios depict drastically contrasting images of the future in terms of population growth, economic development, and changes to life expectancy, this article uses risk acceptance criteria that are based on socioeconomic considerations to highlight the need for nonuniform risk acceptability across climate change scenarios. For this purpose, the optimum implied cost of averting a fatality derived based on the life quality index concept and the value of a quality-adjusted life year derived based on the time principle of acceptable life risk are assessed in three different climate change scenarios for Sweden. Additionally, an illustrative example that assesses the acceptable probability of failure of a steel rod under axial tension in the different climate change scenarios is presented. It is shown that risk acceptance criteria can vary considerably across the different climate change scenarios (e.g., more than 190% variation in the acceptable probability of failure for Sweden in the considered example). This article demonstrates that the ability of societies to afford risk-reducing measures may vary considerably across the different climate change scenarios. Hence, it can be concluded that (1) in the context of climate change risk assessments, risk acceptance criteria need to be developed to account for the different climate change scenarios, and (2) these criteria may vary considerably across the different climate change scenarios. Finally, relevant challenges and research needs are also provided.