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

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.

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.

References

  1. Arrow, K. et al. Determining benefits and costs for future generations. Science 341, 349–350 (2013).

    Article 
    CAS 

    Google Scholar     

  2. Weitzman, M. L. Gamma discounting. Am. Econ. Rev. 91, 260–271 (2001).

    Article 

    Google Scholar     

  3. Aldy, J. E., Kotchen, M. J., Stavins, R. N. & Stock, J. H. Keep climate policy focused on the social cost of carbon. Science 373, 850–852 (2021).

    Article 
    CAS 

    Google Scholar     

  4. Wagner, G. et al. Eight priorities for calculating the social cost of carbon. Nature 590, 548–550 (2021).

    Article 
    CAS 

    Google Scholar     

  5. Standards of Performance for New, Reconstructed, and Modified Sources and Emissions Guidelines for Existing Sources: Oil and Natural Gas Sector Climate Review (US Environmental Protection Agency, 2022).

  6. Groom, B. & Hepburn, C. Reflections—looking back at social discounting policy: the influence of papers, presentations, political preconditions, and personalities. Rev. Environ. Econ. Policy 11, 336–356 (2017).

    Article 

    Google Scholar     

  7. Dasgupta, P. Discounting climate change. J. Risk Uncertain. 37, 141–169 (2008).

    Article 

    Google Scholar     

  8. Broome, J. Efficiency and future generations. Econ. Phil. 34, 221–241 (2018).

    Article 

    Google Scholar     

  9. Groom, B. & Maddison, D. New estimates of the elasticity of marginal utility for the UK. Environ. Resour. Econ. 72, 1155–1182 (2019).

    Article 

    Google Scholar     

  10. Nesje, F. Cross-Dynastic Intergenerational Altruism Working Paper No. 9626 (CESifo, 2022).

  11. Beard, S. The dilemma of discounting: the impossibility of setting a context independent Ramsey discount rate for human wellbeing. Rerum Causae 3, 11–21 (2011).


    Google Scholar     

  12. Broome, J. Discounting the future. Phil. Public Aff. 23, 128–156 (1994).

    Article 

    Google Scholar     

  13. Caney, S. Climate change and the future: discounting for time, wealth, and risk. J. Soc. Phil. 40, 163–186 (2009).

    Article 

    Google Scholar     

  14. Greaves, H. Discounting for public policy: a survey. Econ. Phil. 33, 391–439 (2017).

    Article 

    Google Scholar     

  15. Heilmann, C. Values in time discounting. Sci. Eng. Ethics 23, 1333–1349 (2017).

    Article 

    Google Scholar     

  16. Kelleher, J. P. Pure time preference in intertemporal welfare economics. Econ. Phil. 33, 441–473 (2017).

    Article 

    Google Scholar     

  17. Medvecky, F. Valuing environmental costs and benefits in an uncertain future: risk aversion and discounting. Erasmus J. Phil. Econ. 5, 1–23 (2012).

    Article 

    Google Scholar     

  18. Mogensen, A. L. The only ethical argument for positive δ? Partiality and pure time preference. Phil. Stud. 179, 2731–2750 (2022).

    Article 

    Google Scholar     

  19. Parfit, D. Reasons and Persons (Oxford Univ. Press, 1984).

  20. Drupp, M. A., Freeman, M. C., Groom, B. & Nesje, F. Discounting disentangled. Am. Econ. J. Econ. Policy 10, 109–134 (2018).

    Article 

    Google Scholar     

  21. Hänsel, M. C. et al. Climate economics support for the UN climate targets. Nat. Clim. Change 10, 781–789 (2020).

    Article 

    Google Scholar     

  22. Nordhaus, W. Projections and uncertainties about climate change in an era of minimal climate policies. Am. Econ. J. Econ. Policy 10, 333–360 (2018).

    Article 

    Google Scholar     

  23. The Green Book (HM Treasury, 2020).

  24. Cost–Benefit Analysis and the Environment: Further Developments and Policy Use (OECD, 2018).

  25. Groom, B., Drupp, M. A., Freeman, M. C. & Nesje, F. The future, now: a review of social discounting. Annu. Rev. Resour. Econ. 14, 467–491 (2022).

    Article 

    Google Scholar     

  26. Howard, P. & Schwartz, J. A. Valuing the future: legal and economic considerations for updating discount rates. Yale J. Regul. 39, 595–657 (2022).


    Google Scholar     

  27. Christensen, P., Gillingham, K. & Nordhaus, W. Uncertainty in forecasts of long-run economic growth. Proc. Natl Acad. Sci. USA 115, 5409–5414 (2018).

    Article 
    CAS 

    Google Scholar     

  28. Rennert, K. et al. Comprehensive evidence implies a higher social cost of CO2. Nature 10, 687–692 (2022).

    Article 

    Google Scholar     

  29. Nordhaus, W. D. A Question of Balance (Yale Univ. Press, 2008).

  30. Stern, N. The Economics of Climate Change: The Stern Review (Cambridge Univ. Press, 2007).

  31. Colyvan, M., Cox, D. & Steele, K. Modelling the moral dimension of decisions. Nous 44, 503–529 (2010).

    Article 

    Google Scholar     

  32. Zuber, S. & Asheim, G. B. Justifying social discounting: the rank-discounted utilitarian approach. J. Econ. Theory 147, 1572–1601 (2012).

    Article 

    Google Scholar     

  33. Sterner, T. & Persson, U. M. An even sterner review: introducing relative prices into the discounting debate. Rev. Environ. Econ. Policy 2, 61–76 (2008).

    Article 

    Google Scholar     

  34. Drupp, M. A. & Hänsel, M. C. Relative prices and climate policy: how the scarcity of nonmarket goods drives policy evaluation. Am. Econ. J. Econ. Policy 13, 168–201 (2021).

    Article 

    Google Scholar     

  35. Emmerling, J., Groom, B. & Wettingfeld, T. Discounting and the representative median agent. Econ. Lett. 161, 78–81 (2017).

    Article 

    Google Scholar     

  36. Fleurbaey, M. & Zuber, S. Discounting, risk and inequality: a general approach. J. Public Econ. 128, 34–49 (2015).

    Article 

    Google Scholar     

  37. Gollier, C. Pricing the Planet’s Future: The Economics of Discounting in an Uncertain World (Princeton Univ. Press, 2013).

  38. Cropper, M. L., Freeman, M. C., Groom, B. & Pizer, W. A. Declining discount rates. Am. Econ. Rev. 104, 538–543 (2014).

    Article 

    Google Scholar     

  39. Valuing Climate Damages: Updating Estimation of the Social Cost of Carbon Dioxide Tech. Rep. (National Academies of Sciences, Engineering, and Medicine, 2017).

  40. Newell, R. G., Pizer, W. A. & Prest, B. C. A discounting rule for the social cost of carbon. J. Assoc. Environ. Resour. Econ. 9, 1017–1046 (2022).


    Google Scholar     

  41. Emmerling, J. et al. The role of the discount rate for emission pathways and negative emissions. Environ. Res. Lett. 14, 104008 (2019).

    Article 
    CAS 

    Google Scholar     

  42. Pindyck, R. S. The use and misuse of models for climate policy. Rev. Environ. Econ. Policy 11, 100–114 (2017).

    Article 

    Google Scholar     

  43. Sunstein, C. R. On not revisiting official discount rates: institutional inertia and the social cost of carbon. Am. Econ. Rev. 104, 547–551 (2014).

    Article 

    Google Scholar     

  44. Nesje, F., Drupp, M., Freeman, C. M. & Groom, B. Replication files for ‘Philosophers and economists agree on climate policy paths but for different reasons’. Zenodo https://doi.org/10.5281/zenodo.7920803 (2023).

  45. Armstrong, J. S. & Overton, T. S. Estimating nonresponse bias in mail surveys. J. Mark. Res. 14, 396–402 (1977).

    Article 

    Google Scholar     

  46. Necker, S. Scientific misbehavior in economics. Res. Policy 43, 1747–1759 (2014).

    Article 

    Google Scholar     

  47. Johnson, T. P. & Wislar, J. S. Response rates and nonresponse errors in surveys. JAMA 307, 1805–1806 (2012).

    Article 
    CAS 

    Google Scholar     

  48. Carleton, T. & Greenstone, M. A guide to updating the US government’s social cost of carbon. Rev. Environ. Econ. Policy 16, 196–218 (2022).

    Article 

    Google Scholar     

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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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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. (2023). https://doi.org/10.1038/s41558-023-01681-w

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  • Received: 05 October 2022

  • Accepted: 24 April 2023

  • Published: 25 May 2023

  • DOI: https://doi.org/10.1038/s41558-023-01681-w

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