Climatic Change

, 108:707 | Cite as

Certainty, uncertainty, and climate change

  • M. Granger MorganEmail author
  • Carnegie Mellon

Uncertainty abounds in issues related to climate science and climate changes, the impacts of those changes, and the efficacy of strategies that might be used to mitigate or adapt to change. There are, however, a few things about which we can be quite certain. There are also a number of things about which many people are certain, but should not be.

Certain and uncertain climate science

Despite the continued efforts of skeptics motivated by a desire for attention or short-term economic interests (Oreskes and Conway 2010), we can be certain about a number of basic facts: human activities have resulted in dramatic increases in the atmospheric concentration of carbon dioxide and a number of other greenhouse gasses; those increased concentrations are changing the climate and will continue to do so; one of those changes will be average warming on a planetary scale. Another unambiguous consequence of rising atmospheric concentrations of carbon dioxide will be the continued acidification of...


Time Preference Assessment Community Expert Elicitation Climate Assessment Exponential Discount 
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.



Preparation of this paper was supported by the Center for Climate and Energy Decision Making (CEDM) at Carnegie Mellon University under a cooperative agreement with the National Science Foundation (SES-0949710). I thank my many collaborators who have helped me in the evolution of my thinking about these matters, most notably Hadi Dowlatabadi, Max Henrion and David Keith.


  1. Budescu DV, Broomell S, Por H (2009) Improving communication of uncertainty in the reports of the Intergovernmental Panel on Climate Change. Psychol Res 20:299–308Google Scholar
  2. Budnitz RJ, Apostolakis G, Boore DM, Cluff LS, Coppersmith KJ, Cornell CA, Morris PA (1995) Recommendations for Probabilistic Seismic Hazard Analysis: Guidance on Uncertainty and the Use of Experts. UCRL-ID 122160. Lawrence Livermore National Laboratory, LivermoreGoogle Scholar
  3. Budnitz RJ, Apostolakis G, Boore DM, Cluff LS, Coppersmith KJ, Cornell CA, Morris PA (1998) Use of technical expert panels: applications to probabilistic seismic hazard analysis. Risk Anal 18(4):463–469CrossRefGoogle Scholar
  4. Casman EA, Morgan MG, Dowlatabadi H (1999) Mixed levels of uncertainty in complex policy models. Risk Anal 19(1):33–42Google Scholar
  5. Curtright A, Morgan MG, Keith D (2008) Expert assessment of future photovoltaic technology. Environ Sci Technol 42:9031–9038CrossRefGoogle Scholar
  6. Davis R (2010) Fundamental constants: big G revisited. Nature 468:181–183CrossRefGoogle Scholar
  7. Dowlatabadi H, Morgan MG (1993) A model framework for integrated studies of the climate problem. Energ Policy 21(3): 209–221. Reprinted in The International Library of Critical Writings in Economics. Blaug M (Series Editor); Kunreuther H, Rose AZ (eds) (2004) The economics of natural hazards. Edward Elgar Publishing CompanyGoogle Scholar
  8. Evans JS, Gray GM, Sielken RL Jr, Smith AE, Valdez-Flores C, Graham JD (1994a) Using of probabilistic expert judgment in uncertainty analysis of carcinogenic potency. Regul Toxicol Pharm 20:15–36CrossRefGoogle Scholar
  9. Evans JS, Graham JD, Gray GM, Sielken RL Jr (1994b) A distributional approach to characterizing low-dose cancer risk. Risk Anal 14:25–34CrossRefGoogle Scholar
  10. Frederick S, Loewenstein G, O’Donoghue T (2002) Time discounting and time preference: a critical review. J Econ Lit XL:351–401CrossRefGoogle Scholar
  11. Frumhoff PC, McCarthy JJ, Melillo JM, Moser SC, Wuebbles DJ (2007) Confronting climate change in the North East: Science, impacts and solutions. A report of the North East Climate Impact Assessment. Available on line at:
  12. Heal G (2009) The economics of climate change: a post-stern perspective. Clim Change 96:275–297CrossRefGoogle Scholar
  13. Henrion M, Fischhoff B (1986) Assessing uncertainty in physical constants. Am J Phys 54:791–798CrossRefGoogle Scholar
  14. IPCC (2007) Climate change 2007: synthesis report. In: Pachauri RK, Reisinger A (eds) Contribution of working groups I, II and III to the fourth assessment report of the intergovernmental panel on climate change, core writing team, IPCC, GenevaGoogle Scholar
  15. Kahneman D, Slovic P, Tversky A (eds) (1982) Judgments under uncertainty: heuristics and biases. Cambridge University PressGoogle Scholar
  16. Lave LB, Dowlatabadi H, McRae GJ, Morgan MG, Rubin ES (1992) Uncertainties of climate change. Nature 355Google Scholar
  17. Lichtenstein S, Fischhoff B, Phillips LD (1982) Calibration of probabilities: the state of the art in 1980. In: Kahneman D, Slovic P, Tversky A (eds) Judgment under uncertainty: heuristics and biases. Cambridge University Press, New YorkGoogle Scholar
  18. Lumina Decision Systems (2011) Details at
  19. Morgan MG (1998) Uncertainty analysis in risk assessment. Hum Ecol Risk Assess 4(1):25–39Google Scholar
  20. Morgan MG, Dowlatabadi H (1996) Learning from integrated assessment of climate change. Clim Change 34:337–368CrossRefGoogle Scholar
  21. Morgan MG, Henrion M (1990) Uncertainty: a guide to dealing with uncertainty in quantitative risk and policy analysis. Cambridge University Press, New YorkGoogle Scholar
  22. Morgan MG, Keith D (1995) Subjective judgments by climate experts. Environ Sci Technol 29(10):468–476CrossRefGoogle Scholar
  23. Morgan MG, Keith D (2008) Improving the way we think about projecting future energy use and emissions of carbon dioxide. Clim Change 90(3):189–215CrossRefGoogle Scholar
  24. Morgan MG, Kandlikar M, Risbey J, Dowlatabadi H (1999) Editorial - Why conventional tools for policy analysis are often inadequate for problems of global change. Clim Change 41:271–281CrossRefGoogle Scholar
  25. Morgan MG, Pitelka LF, Shevliakova E (2001) Elicitation of expert judgments of climate change impacts on forest ecosystems. Clim Change 49(3):279–307CrossRefGoogle Scholar
  26. Morgan MG, Fischhoff B, Bostrom A, Atman C (2002) Risk Communication: A mental models approach, Cambridge University Press, New York.Google Scholar
  27. Morgan MG, Cantor R, Clark WC, Fisher A, Jacoby HD, Janetos AC, Kinzig AP, Melillo J, Street RB, Wilbanks TJ (2005) Learning from the U.S. National Assessment of Climate Change. Environ Sci Technol 39:9023–9032CrossRefGoogle Scholar
  28. Morgan MG, Adams P, Keith D (2006) Elicitation of expert judgments of aerosol forcing. Clim Change 75:195–214CrossRefGoogle Scholar
  29. Morgan MG, Dowlatabadi H, Henrion M, Keith D, Lempert R, McBride S, Small M, Wilbanks T (2009) Best practice approaches for characterizing, communicating, and incorporating scientific uncertainty in decisionmaking. CCSP 5.2, A Report by the Climate Change Science Program and the Subcommittee on Global Change Research. National Oceanic and Atmospheric Administration, WashingtonGoogle Scholar
  30. Moss R et al (2010) The next generation of scenarios for climate change research and assessment. Nature 463:747–756CrossRefGoogle Scholar
  31. Moss R, Schneider SH (2000) Uncertainties in the IPCCTAR: recommendations to authors for more consistent assessment and reporting. In: Pachauri R, Taniguchi T, Tanaka K (eds) Guidance papers on the cross cutting issues of the third assessment report of the IPCC. Intergovernmental Panel on Climate Change, Geneva, Switzerland, pp. 33–51. Available at:
  32. Nakicenovic N, Swart R (eds) (2000) IPCC special report on emissions scenarios. Cambridge: Cambridge University PressGoogle Scholar
  33. Oreskes N, Conway EM (2010) Merchants of doubt: How a handful of scientists obscured the truth on issues from tobacco smoke to global warming. Bloomsbury PressGoogle Scholar
  34. Rubin ES, Lave LB, Morgan MG (1991–92) Keeping climate research relevant. Issues Sci Technol VIII(2):47–55Google Scholar
  35. Schelling TC (1995) Intergenerational discounting. Energ Policy 23:395–402CrossRefGoogle Scholar
  36. Schneider SW (2001) What is “dangerous” climate change? Nature 411:17–19CrossRefGoogle Scholar
  37. Smil V (2003) Energy at the crossroads. MIT Press, CambridgeGoogle Scholar
  38. Spetzler CS, Staël von Holstein C-AS (1975) Probability encoding in decision analysis. Manage Sci 22:340–352CrossRefGoogle Scholar
  39. Stern N (1982) The Eckert-Mauchly computers: conceptual triumphs, commercial tribulations. Technol Cult 23:569–582CrossRefGoogle Scholar
  40. US Environmental Protection Agency (1996) Proposed guidelines for cancer risk assessment, EPA/600P-92/003 C, Office of Research and Development, Environmental Protection Agency, WashingtonGoogle Scholar
  41. US National Assessment (2000) Climate change impacts on the United States, overview report of the national assessment synthesis team for the US National Assessment of the Potential Consequences of Climate Variability and Change, Cambridge University PressGoogle Scholar
  42. Viscusi WK (1995) Fatal tradeoffs: public and private responsibilities for risk. Oxford University PressGoogle Scholar
  43. Wallsten TS, Budescu DV, Rapoport A, Zwick R, Forsyth B (1986) Measuring the vague meanings of probability terms. J Exp Psychol Gen 155(4):348–365CrossRefGoogle Scholar
  44. Zickfeld K, Levermann A, Kuhlbrodt T, Rahmstorf S, Morgan MG, Keith D (2007) Expert judgments on the response on the Atlantic meridional overturning circulation to climate change. Clim Change 82:235–265CrossRefGoogle Scholar
  45. Zickfeld K, Morgan MG, Frame D, Keith D (2010) Expert judgments about transient climate response to alternative future trajectories of radiative forcings. P Natl Acad Sci USA 107:12451–12456CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  1. 1.Head, Department of Engineering and Public PolicyCarnegie Mellon UniversityPittsburghUSA

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