Philosophers and economists agree on climate policy paths but for different reasons

Economists often dominate public climate policy discussions, such as those on the proper social discount rate and optimal climate pathways. This Article shows that philosophers, experts in underlying ethical matters, generally agree with economists but put more weight on various normative considerations. The estimated value to society from climate change mitigation is highly sensitive to the long-term social discount rate. Governmental discounting guidance has almost exclusively been influenced by economists, although it is not clear that they possess any special expertise on intergenerational ethics. Here, by contrast, we report the views of philosophers, who are the most trained in ethical matters. We show that, as a group, these experts offer strong support for a real social discount rate of 2%, a value that is also predominantly backed by economists. We find multidisciplinary support for climate policy paths in line with the United Nations climate targets when views on discounting determinants are applied within a recent update of the DICE integrated assessment model. However, this apparent agreement hides important differences in views on how the ethics of intergenerational welfare can be better incorporated into climate policy evaluation.

Automated summary

This article reveals that economists, who often dominate public climate policy discussions, generally agree with philosophers on ethical matters, but prioritize normative considerations differently. The estimated value of climate change mitigation is highly influenced by the long-term social discount rate. Despite economists' exclusive influence on governmental discounting guidance, it is unclear whether they possess expertise in intergenerational ethics. In contrast, philosophers, who are more knowledgeable in ethical matters, strongly support a real social discount rate of 2%, a value also backed by economists. While there is multidisciplinary support for climate policy paths aligned with UN climate targets, there are significant differences in views on how to incorporate intergenerational welfare ethics into climate policy evaluation.