The following terms were sent to Al Gore Tuesday, June 19th, 2007.
Al Gore has claimed that there are scientific forecasts that the earth will become warmer and that this will occur rapidly. University of Pennsylvania Professor J. Scott Armstrong, author of Principle of Forecasting: A Handbook for Researchers and Practitioners, and Kesten C. Green, of Monash University (and Armstrong’s Co-Director of forecastingprinciples.com), have been unable to locate a scientific forecast to support that viewpoint. As a result, Scott Armstrong offers a challenge to Al Gore that he will be able to make more accurate forecasts of annual mean temperatures than those that can be produced by current climate models.
The general objective of the challenge is to promote the proper use of science in formulating public policy. This involves such things as full disclosure of forecasting methods and data, and the proper testing of alternative methods. A specific objective is to develop useful methods to forecast global temperatures. Hopefully other competitors would join to show the value of their forecasting methods. These are objectives that we share and they can be achieved no matter who wins the challenge.
Al Gore is invited to select any currently available fully disclosed climate model to produce the forecasts (without human adjustments to the model’s forecasts). Scott Armstrong’s forecasts will be based on the naive (no-change) model; that is, for each of the ten years of the challenge, he will use the most recent year’s average temperature at each station as the forecast for each of the years in the future. The naïve model is a commonly used benchmark in assessing forecasting methods and it is a strong competitor when uncertainty is high or when improper forecasting methods have been used.
Specifically, the challenge will involve making forecasts for ten weather stations that are reliable and geographically dispersed. An independent panel composed of experts agreeable to both parties will designate the weather stations. Data from these sites will be listed on a public web site along with daily temperature readings and, when available, error scores for each contestant.
Starting at the beginning of 2008, one-year ahead forecasts then two-year ahead forecasts, and so on up to ten-year-ahead forecasts of annual “mean temperature” will be made annually for each weather station for each of the next ten years. Forecasts must be submitted by the end of the first working day in January. Each calendar year would end on December 31.
The criteria for accuracy would be the average absolute forecast error at each weather station. Averages across stations would be made for each forecast horizon (e.g., for a six-year ahead forecast). Finally, simple unweighted averages will be made of the forecast errors across all forecast horizons. For example, the average across the two-year ahead forecast errors would receive the same weight as that across the nine-year-ahead forecast errors. This unweighted average would be used as the criterion for determining the winner.
Terms of the challenge can be modified by mutual agreement.
From a scientific point of view Gore would be a fool to accept the challenge, however, from a political point of view Gore should absolutely accept. We have had gloom and doom forecasts for almost thirty years now (fifty if you want to count when the "doom" involved a "coming ice age"), and they haven't been correct yet. So Gore would lose this bet, but no one would know that for 10 years! The political considerations of the AGW hysteria will shake out (or has the potential for shaking out) in the next couple of years. That being the case, Gore should put on his best pseudo-science bravado and accept the challenge. He can crow about how he is "putting his money where his mouth is" and score huge political points.
Here is more on the view of forecasting inherent in this challenge: From Sp!ked
Armstrong got the idea for the climate change wager from the late Julian Simon, an economist at the University of Maryland who was a friend of Armstrong’s. In 1980, Simon bet the population scaremonger Paul Ehrlich that natural resources were not scarce and shrinking, as Ehrlich and other Malthusian environmentalists claimed. Ehrlich accepted: he chose five metals (copper, chrome, nickel, tin and tungsten) and bet Simon that in 10 years’ time the price of these metals would have risen exponentially due to their continued depletion by human adventure. In fact, when 1990 arrived, the price of all of Ehrlich’s metals had fallen. Simon won the bet and Ehrlich handed him a cheque for $576.07. Armstrong expects to win his bet with Gore, too (that’s if Gore accepts; he hasn’t responded yet). But even if he were to lose, ‘at least I will have started a debate about forecasting’, he tells me.
Armstrong and his colleague Kesten Green, senior research fellow at Monash University in Australia and also an expert on forecasting, have been conducting research into the global-warming forecasts put out by Gore and organisations such as the Intergovernmental Panel on Climate Change (IPCC). And they discovered that most climate-change forecasters use bad methodology. They are set to present their findings at an International Symposium on Forecasting in New York on Wednesday. ‘What we have is climate forecasters effectively translating their own opinions into maths’, says Armstrong. ‘Their claims are not built on clear and thorough scientific forecasts but on their own outlooks.’ In Global Warming: Forecasts by Scientists versus Scientific Forecasts – the paper they are presenting at the symposium, which spiked has seen – Armstrong and Green point out that the IPCC’s Working Group One Report predicted ‘dramatic and harmful increases in average world temperatures over the next 92 years’, and they ask: ‘Are these forecasts a good basis for developing public policy?’ The answer provided in their paper is an emphatic ‘no’.
Armstrong and Green – whom I’m sure won’t mind being referred to as forecasting geeks – argue that those who predict sweeping changes in the climate break many of the golden rules of forecasting, as laid out in the 2001 book The Principles of Forecasting. In their paper, they assessed ‘the extent to which long-term forecasts of global average temperatures have been derived using evidence-based forecasting methods’. They surveyed 51 scientists and others involved in making global-warming predictions, asking them to provide scientific articles that contained credible forecasts to underpin their view that temperature will rise rapidly. Most of those surveyed – 30 out of 51 – cited the IPCC Report as the best forecasting source. Yet according to Armstrong and Green, the forecasts in the IPCC Report are not the outcome of scientific forecasting procedures – rather the Report presents ‘the opinions of scientists transformed by mathematics and obscured by complex writing’. Indeed, in their ‘forecasting audit’ of the IPPC Report, Armstrong and Green found that it violated 72 of the principles of forecasting.
Such as? ‘Well, some of the principles of forecasting can appear counterintuitive, so bear with me’, says Armstrong. ‘One of the principles is that agreement amongst experts is actually not a very good measure of accuracy. This is especially true if experts are working closely together, and towards a certain goal, as they do in the IPCC. Such an atmosphere does not tend to generate reliable or accurate forecasts. Another principle of forecasting is that when there is uncertainty, your forecasts should be conservative, you should hedge your bets a little bit. The IPCC and others do exactly the opposite: despite their uncertainty, the fact that they don’t know for certain what will happen, they are radical in their predictions of warming and destruction and so on.’
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