Climatic Change

, Volume 117, Issue 4, pp 663–675 | Cite as

Sensitivity of multi-gas climate policy to emission metrics

  • Steven J. SmithEmail author
  • Joseph Karas
  • Jae Edmonds
  • Jiyong Eom
  • Andrew Mizrahi


The Global Warming Potential (GWP) index is currently used to create CO2-equivalent emission totals for multi-gas greenhouse targets. While many alternatives have been proposed, it is not possible to uniquely define a metric that captures the different impacts of emissions of substances with widely disparate atmospheric lifetimes, which leads to a wide range of possible index values. We examine the sensitivity of emissions and climate outcomes to the value of the index used to aggregate methane emissions using a technologically detailed integrated assessment model. The methane index is varied between 4 and 70, with a central value of 21, which is the 100-year GWP value currently used in policy contexts. We find that the sensitivity to index value is, at most, 10–18 % in terms of methane emissions but only 2–3 % in terms of the maximum total radiative forcing change, with larger regional emissions differences in some cases. The choice of index also affects estimates of the cost of meeting a given end of century forcing target, with total two-gas mitigation cost increasing by 7–9 % if the index is increased, and increasing in most scenarios from 4 to 23 % if the index is lowered, with a slight (1 %) decrease in total cost in one case. We find that much of the methane abatement occurs as the induced effect of CO2 abatement rather than explicit abatement, which is one reason why climate outcomes are relatively insensitive to the index value. We also find that the near-term climate benefit of increasing the methane index is small.


Methane Emission Climate Policy Global Warming Potential Carbon Price Marginal Abatement Cost 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



Work on this project was supported by the Climate Change Division, U.S. Environmental Protection Agency, with additional support from the Office of Science (BER), U. S. Department of Energy. The authors would like to thank the three anonymous reviewers, whose comments substantially improved the paper.

Supplementary material

10584_2012_565_MOESM1_ESM.pdf (542 kb)
ESM 1 (PDF 542 kb)


  1. Aaheim A, Fuglestvedt JS, Godal O (2006) Costs savings of a flexible multi-gas climate policy. Energy J (Special Issue #3) 485–501Google Scholar
  2. Archer D et al (2009) Atmospheric lifetime of fossil fuel carbon dioxide. Annu Rev Earth Planet Sci 37:117–134CrossRefGoogle Scholar
  3. Clarke L, Edmonds J, Jacoby H, Pitcher H, Reilly J, Richels R (2007) CCSP synthesis and assessment product 2.1, Part A: scenarios of greenhouse gas emissions and atmospheric concentrations. U.S. Government Printing Office, WashingtonGoogle Scholar
  4. Daniel JS et al (2011) Limitations of single-basket trading: lessons from the Montreal protocol for climate policy. Clim Chang. doi: 10.1007/s10584-011-0136-3
  5. Edmonds J, Reilly J (1985) Global energy: assessing the future. Oxford University Press, New YorkGoogle Scholar
  6. Ehhalt D et al (2001) Chapter 4. Atmospheric chemistry and greenhouse gases. In: Houghton JT et al (eds) Climate change 2001: the scientific basis. Cambridge University Press, CambridgeGoogle Scholar
  7. Eckaus RS (1992) Comparing the effects of greenhouse gas emissions on global warming. Energy J 13:25–35Google Scholar
  8. Fuglestvedt JS et al (2003) Metrics of climate change: assessing radiative forcing and emission indices. Clim Chang 58:267–331. doi: 10.1023/A:1023905326842 CrossRefGoogle Scholar
  9. Fuglestvedt JS, Shine KP, Berntsen T, Cook J, Lee DS, Stenke A, Skeie RB, Velders GJM, Waitz IA (2010) Transport impacts on atmosphere and climate: metrics. Atmos Environ 44:4648–4677CrossRefGoogle Scholar
  10. Godal O, Fuglestvedt J (2002) Testing 100-year global warming potentials: impacts on compliance costs and abatement profile. Clim Chang 52(1–2):93–127CrossRefGoogle Scholar
  11. Johansson D, Persson U, Azar C (2006) The cost of using global warming potentials: analysing the trade off between CO2, CH4 and N2O. Clim Chang 77(3–4):291–309CrossRefGoogle Scholar
  12. Johansson DJA (2012) Economics- and physical-based metrics for comparing greenhouse gases. Clim Chang 110:123–141CrossRefGoogle Scholar
  13. Kim SH, Edmonds J, Lurz J, Smith SJ and Wise M (2006) The ObjECTS Framework for Integrated Assessment: Hybrid Modeling of Transportation. Energy J (Special Issue #2) 51–80Google Scholar
  14. Manne AS, Richels RG (2001) An alternative approach to establishing trade-offs among greenhouse gases. Nature 5:675–677CrossRefGoogle Scholar
  15. O’Neill BC (2003) Economics, natural science, and the costs of global warming potentials. Clim Chang 58:251–260CrossRefGoogle Scholar
  16. Plattner G-K, Stocker T, Midgley P, Tignor M (eds) (2009) IPCC expert meeting on the science of alternative metrics. IPCC Working Group I Technical Support Unit, BernGoogle Scholar
  17. Reisinger A, Meinshausen M, Manning M, Bodeker G (2010) Uncertainties of global warming metrics: CO2 and CH4. Geophys Res Lett 37:L14707CrossRefGoogle Scholar
  18. Reisinger A, Meinshausen M and Manning M (2011) Future changes in global warming potentials under representative concentration pathways. Environ Res Lett 6(2):1–8Google Scholar
  19. Schimel D et al (1996) Radiative forcing of climate change. In: Houghton JT et al (ed) Climate Change 1995: The Science of Climate Change. Contribution of Working Group I to the Second Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, CambridgeGoogle Scholar
  20. Shine KP, Fuglestvedt JS, Hailemariam K, Stuber N (2005) Alternatives to the global warming potential for comparing climate impacts of emissions of greenhouse gases. Clim Chang 68:281–302. doi: 10.1007/s10584-005-1146-9 CrossRefGoogle Scholar
  21. Shine KP, Berntsen T, Fuglestvedt JS, Stuber N, Skeie RB (2007) Comparing the climate effect of emissions of short and long lived climate agents. Phil Trans R Soc A 365:1903–1914CrossRefGoogle Scholar
  22. Shine K (2009) The global warming potential—the need for an interdisciplinary retrial. Clim Chang 96(4):467–472. doi: 10.1007/s10584-009-9647-6 CrossRefGoogle Scholar
  23. Smith SJ (2003) The evaluation of greenhouse gas indices. Clim Chang 58(3):261–265, guest editorialCrossRefGoogle Scholar
  24. Smith SJ and Wigley TML (2006) Multi-Gas Forcing Stabilization with the MiniCAM. Energy J (Special Issue #3) 373–391Google Scholar
  25. Smith SJ, Wigley TML (2000a) Global warming potentials: 1. Climatic implications of emissions reductions. Clim Chang 44(4):445–457CrossRefGoogle Scholar
  26. Smith SJ, Wigley TML (2000b) Global warming potentials: 2. Accuracy. Clim Chang 44(4):459–469CrossRefGoogle Scholar
  27. Thomson AM, Calvin KV, Smith SJ, Kyle GP, Volke AC, Patel PL, Delgado Arias S, Bond-Lamberty B, Wise MA, Clarke LE, Edmonds JA (2011) RCP4.5: a pathway for stabilization of radiative forcing by 2100. Clim Chang 109(1–2):77–94. doi: 10.1007/s10584-011-0151-4 CrossRefGoogle Scholar
  28. UNEP (2011) Near-term climate protection and clean air benefits: actions for controlling short-lived climate forcers. United Nations Environment Programme (UNEP), Nairobi, 78 ppGoogle Scholar
  29. West JJ, Fiore AM, Horowitz LW, Mauzerall DL (2006) Global health benefits of mitigating ozone pollution with methane emission controls. Proc Natl Acad Sci 103(11):3988–3993. doi: 10.1073/pnas.0600201103 CrossRefGoogle Scholar
  30. Weyant JP, de la Chesnaye FC, and Blanford GJ (2006) Overview of EMF-21: Multigas Mitigation and Climate Policy. Energy J, (Special Issue #3):1–32Google Scholar
  31. Wigley TML (1998) The Kyoto Protocol: CO2, CH4 and climate implications. Geophys Res Lett 25(13):2285–2288CrossRefGoogle Scholar
  32. Wigley TML, Smith SJ, Prather MJ (2002) Radiative forcing due to reactive Gas emissions. J Clim 15(18):2690–2696CrossRefGoogle Scholar
  33. Wise MA, Calvin KV, Thomson AM, Clarke LE, Bond-Lamberty B, Sands RD, Smith SJ, Janetos TC, Edmonds JA (2009) Implications of limiting CO2 concentrations on land use and energy. Science 324:1183–1186CrossRefGoogle Scholar
  34. Wuebbles D, Edmonds J (1991) A primer on greenhouse gases. Lewis Publishers, ChelseaGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Steven J. Smith
    • 1
    Email author
  • Joseph Karas
    • 1
  • Jae Edmonds
    • 1
  • Jiyong Eom
    • 1
  • Andrew Mizrahi
    • 1
  1. 1.Joint Global Change Research InstitutePacific Northwest National LaboratoryCollege ParkUSA

Personalised recommendations