Philosophers reinforce economists' support for UN climate targets, but disagree on why

Abstract

The estimated value to society from climate change mitigation is highly sensitive to the long-term social discount rate (SDR). While it is not clear that they possess any special expertise on the ethics of intergenerational welfare, governmental discounting guidance has almost exclusively been influenced by economists. Our study, by contrast, reports the views of a disciplinary group of experts who are most trained in ethical matters; philosophers. We show that, as a group, these experts offer strong support for a real SDR of 2%; a value that is also predominantly backed by economists. We find multidisciplinary support for climate policy paths in line with the UN 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.

Climate Policy Curves: Linking Policy Choices to Climate Outcomes

“…At one extreme, an ambitious climate policy starts with a high initial carbon price and a low subsequent growth rate, which may be socially optimal (Hänsel et al, 2020;Nesje et al, 2022). At the other extreme, policymakers might start with a low initial carbon price, but promise a high CO2 price growth rate, which shifts the bulk of the mitigation burden to the future (Gollier, 2021).…”