September 3, 2009: "Validity of climate change forecasting for public policy decision making", to be published in the International Journal of Forecasting. Authors: Dr. Kesten C. Green of the Business and Economic Forecasting Unit, Monash University, Australia; Professor J. Scott Armstrong, of The Wharton School, University of Pennsylvania; and Dr. Willie Soon, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA.
The history of global temperatures over periods of about 100 has been remarkably stable, and we should want very accurate forecasts of future temperatures (and precipitation). Given this, the IPCC has bent over backwards to provide object proof that theirs are, in fact, reliable, right? Not so. The models used by the Intergovernmental Panel on Climate Change (IPCC) have never been validated, which is why the IPCC calls their results "projections." Validating such models is complicated by the lack of actual long-term observations (that's real field-gathered data) against which the model results may be compared. In reality, only time will tell if the IPCC projections are on or off target.
But Green, et al., in their paper now in press, compare simple zero-change forecasts to the IPCC projections
that are the basis for international calls for major policy measures. "Using the IPCC warming rate for our demonstration, we projected the rate successively over a period [parallel to that contemplated by the IPCC's] scenario of exponential CO2 growth—the years 1851 to 1975. The errors from the [IPCC] projections were more than seven times greater than the errors from the benchmark method [applied by these authors]."
According to this analysis, then, policymakers around the world could assume that temperatures would not change from one year to the next and still likely have a relatively small level of error versus actual temperature at the end of the forecast cycle. (Drs. Green and Armstrong are experts in forecasting, while Dr Soon's training and research are in atmospheric and space physics.)
Read the whole paper.
Visit Armstrong and Green's forecasting site.
Read a press release from New Zealand: "Global warming legislation would fail", that references this paper and includes quotes from the authors.