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

Nature Climate Change volume 13, pages 515–522 (2023)Cite this article

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Abstract

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.

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Fig. 1: Comparison of philosopher and economist recommendations on intergenerational discounting and key determinants.
Fig. 2: Philosophers’ views on climate policy paths.
Fig. 3: Philosopher and economist agreement on climate policy paths.

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Data availability

The data that support the plots in this paper and other findings of this study are available at the following repository: https://doi.org/10.5281/zenodo.7920803.

Code availability

All code used to produce the analysis is available at the following repository: https://doi.org/10.5281/zenodo.7920803. The details of implementation can be found in Methods.

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Acknowledgements

We thank our many survey respondents; seminar audiences at LSE, Copenhagen, EAERE 2021 and Miljøøkonomisk konference 2021; and G. Asheim, A. Blok, J. Broome, H. Greaves, K. Mintz-Woo, K. Nyborg, P. G. Piacquadio and P. B. Sørensen for helpful comments. We also thank M. Hänsel for providing an additional run from the updated DICE model and M. Lustig for excellent research assistance. We acknowledge support from the LSE, STICERD, CREE funded by Norwegian Research Council (grant no. 209698); NATCOOP funded by the European Research Council (grant no. 678049); and the DFG under Germany’s Excellence Strategy (EXC 2037 and CLICCS) project no. 390683824, contribution to the Center for Earth System Research and Sustainability (CEN) of Universität Hamburg. B.G. is the Dragon Capital Chair of Biodiversity Economics, funded by Dragon Capital.

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Authors and Affiliations

  1. Department of Economics, University of Copenhagen, Copenhagen, Denmark

    Frikk Nesje

  2. CESifo Research Network, Munich, Germany

    Frikk Nesje & Moritz A. Drupp

  3. Department of Economics and Center for Earth System Research and Sustainability (CEN), University of Hamburg, Hamburg, Germany

    Moritz A. Drupp

  4. School for Business and Society, University of York, York, UK

    Mark C. Freeman

  5. Dragon Capital Chair in Biodiversity Economics, LEEP Institute, Department of Economics, University of Exeter Business School, Exeter, UK

    Ben Groom

  6. Grantham Research Institute on Climate Change and the Environment, London School of Economics and Political Science, London, UK

    Ben Groom

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  1. Frikk Nesje
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Contributions

F.N., M.A.D., M.C.F. and B.G. designed the research. F.N., M.A.D. and B.G. analysed the data. F.N., M.A.D., M.C.F. and B.G. wrote the paper.

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Correspondence to Ben Groom.

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Nature Climate Change thanks Lisa Rennels and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Figs. 1 and 2, Table 1 and Discussion.

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Nesje, F., Drupp, M.A., Freeman, M.C. et al. Philosophers and economists agree on climate policy paths but for different reasons. Nat. Clim. Chang. 13, 515–522 (2023). https://doi.org/10.1038/s41558-023-01681-w

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