Green, Kesten C and Armstrong, J Scott and Soon, Willie (2008): Benchmark forecasts for climate change.
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We assessed three important criteria of forecastability—simplicity, certainty, and variability. Climate is complex due to many causal variables and their variable interactions. There is uncertainty about causes, effects, and data. Using evidence-based (scientific) forecasting principles, we determined that a naïve “no change” extrapolation method was the appropriate benchmark. To be useful to policy makers, a proposed forecasting method would have to provide forecasts that were substantially more accurate than the benchmark. We calculated benchmark forecasts against the UK Met Office Hadley Centre’s annual average thermometer data from 1850 through 2007. For 20- and 50-year horizons the mean absolute errors were 0.18°C and 0.24°C. The accuracy of forecasts from our naïve model is such that even perfect forecasts would be unlikely to help policy makers. We nevertheless evaluated the Intergovernmental Panel on Climate Change’s 1992 forecast of 0.03°C-per-year temperature increases. The small sample of errors from ex ante forecasts for 1992 through 2008 was practically indistinguishable from the naïve benchmark errors. To get a larger sample and evidence on longer horizons we backcast successively from 1974 to 1850. Averaged over all horizons, IPCC errors were more than seven-times greater than errors from the benchmark. Relative errors were larger for longer backcast horizons.
|Item Type:||MPRA Paper|
|Original Title:||Benchmark forecasts for climate change|
|Keywords:||backcasting; climate model; decision making; ex ante forecasts; out-of-sample errors; predictability; public policy; relative absolute errors; unconditional forecasts|
|Subjects:||C - Mathematical and Quantitative Methods > C5 - Econometric Modeling > C53 - Forecasting and Prediction Methods; Simulation Methods
O - Economic Development, Technological Change, and Growth > O2 - Development Planning and Policy
Q - Agricultural and Natural Resource Economics; Environmental and Ecological Economics > Q5 - Environmental Economics > Q54 - Climate; Natural Disasters; Global Warming
|Depositing User:||Kesten Green|
|Date Deposited:||15. Dec 2008 02:41|
|Last Modified:||15. Feb 2013 21:31|
Armstrong, J.S. (1985). Long-Range Forecasting. New York: John Wiley.
Armstrong, J.S. (2001). Principles of Forecasting. Boston: Kluwer.
Armstrong, J. S., Green, K. C., & Soon, W., (2008), Polar Bear Population Forecasts: A Public-Policy Forecasting Audit, Interfaces (with commentary and reply), 38, 381-405.
Camp, C. D., & Tung, K.-K. (2007). Surface warming by the solar cycle as revealed by the composite mean difference projection. Geophysical Research Letters, 34, L14703, doi:10.1029/2007GL030207.
Carter, R. M., de Freitas, C. R., Goklany, I. M., Holland, D., & Lindzen, R. S. (2006). The Stern Review: A Dual Critique, Part I: The Science. World Economics, 7, 167-198. Green, K.C., & Armstrong, J.S. (2007). Global warming: Forecasts by scientists versus scientific forecasts, Energy & Environment, 18, 997-1022.
Hansen, J. (2008). Tipping point: Perspective of a climatologist. In State of the Wild 2008-2009: A Global Portrait of Wildlife, Wildlands, and Oceans. W. Woods, Ed. Wildlife Conservation Society/Island Press, pp. 6-15.
IPCC (1990). Climate Change: The IPCC Scientific Assessment. Edited by J.T. Houghton, G.J. Jenkins, and J.J. Ephraums. Cambridge University Press: Cambridge, United Kingdom.
IPCC (1992). Climate Change 1992: The Supplementary Report to the IPCC Scientific Assessment. Edited by J.T. Houghton, B.A. Callander, and S.K. S.K. Varney. Cambridge University Press: Cambridge, United Kingdom.
IPCC (2007). Summary for Policymakers, in Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
Lindzen, R. S. (2009). Climate Science: Is it currently designed to answer questions? Forthcoming in proceedings of Creativity and Creative Inspiration in Mathematics, Science, and Engineering: Developing a Vision for the Future: San Marino, August 2008.
McKibben, W. (2007). Warning on warming. New York Review of Books, 54, 15 March.
McKitrick, R., & Michaels, P. J. (2007). Quantifying the influence of anthropogenic surface processes and inhomogeneities on gridded global climate data. Journal of Geophysical Research, 112, doi:10.1029/2007JD008465.
Soon, W. (2007) Implications of the secondary role of carbon dioxide and methane forcing in the climate change: Past, present and future. Physical Geography, 28, 97-125.
Soon, W. (2009). The solar Arctic connection on multidecadal to centennial timescales: Empirical evidence, mechanistic explanation, and testable consequences. Physical Geography, under review.
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