Among the issues most commonly discussed are individuality, the rights of the individual, the limits of legitimate government, morality, history, economics, government policy, science, business, education, health care, energy, and man-made global warming evaluations. My posts are aimed at thinking, intelligent individuals, whose comments are very welcome.

"No matter how vast your knowledge or how modest, it is your own mind that has to acquire it." Ayn Rand

06 August 2008

Poor Forecasting of IPCC 2007 4th Assessment

The 2007 assessment report by the United Nations Intergovernmental Panel on Climate Change was examined and assessed by Kesten C. Green and J. Scott Armstrong, who are specialists in scientific forecasting methodologies. Green is with the Business and Economic Forecasting Unit, Monash University, Victoria, Australia and Armstrong is a professor at The Wharton School, University of Pennsylvania. Armstrong founded a number of journals on scientific forecasting and has written several books on the subject.

In an article published in Energy & Environment, they examine the IPCC report of 2007 for its use of scientific forecasting principles. This is the latest U.N. report claiming that man is causing dramatic increases in world temperatures and what these increases will be over the next 92 years. Green and Armstrong conclude that these forecasts by the U.N. IPCC violate scientific forecasting principles badly and are not a good basis for developing scientific or public policy.

Chapter 8 of the report provides some information, albeit inadequate, on the forecasting methodology used by the IPCC. It turns out that a huge effort was made in the 1990s to establish what good scientific principles for forecasting were. Many forecasting scientists made a joint effort to elaborate these principles and established 140 principles. Green and Armstrong used these principles to judge the scientific methodology of the forecasts made in the IPCC report and found that there was enough information in the report to make that judgment on 89 of the 140 principles. The IPCC violated 72 of the 89 principles for which sufficient information was provided to make a judgment! Green and Armstrong say that many individual failures to follow a particular principle would of itself make nonsense of the 92 year predictions of the report.

This is a very damning evaluation of the IPCC report and the predictions it makes. "The forecasts in the Report are not the outcome of scientific procedures." "We have been unable to identify any scientific forecasts of global warming. Claims that the Earth will get warmer have no more credence than saying that it will get colder."

Some further comments of interest are:

  • "Complex models (those involving nonlinearities and interactions) harm accuracy because their errors multiply."
  • "Given even modest uncertainty, prediction intervals are enormous." This means that a prediction of a future value of a property will have very large errors. Predicting the sales of General Motors over the next five years is a much simpler problem than predicting average global climate over 92 years, but the error in predicting General Motors sales is still likely to be very large.
  • "When there is uncertainty in forecasting, forecasts should be very conservative."
Among other interesting comments in this article is a reference to a surveys performed by Bray and von Storch in 1996 and in 2003 of 1,060 respondent climate scientists throughout the world. 47% disagreed with the statement that "Climate models can accurately predict future climates." 35% did agree with the statement. One of the things that people do not properly appreciate is how the U.N. IPCC has weighted its selection of scientists to participate in the report to favor those who are anthropogenic global warming alarmists and tends to disregard the judgment of those who disagree in the summaries written for the IPCC assessments.

The IPCC reports are principally about pretense, not about good science.

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