The Global Warming Challenge

Some things are hard to forecast. In such cases forecasters find it hard to beat a simple prediction that things will not change. When Kesten Green, Scott Armstrong, and Willie Soon tested the forecast of global average temperatures apparently preferred by Al Gore (the IPCC’s +0.03C per year scenario) for the years of exponential CO2 emissions growth from 1851 to 1975, they found the IPCC “forecast” errors were more than seven times bigger than the no-change benchmark errors. Their International Journal of Forecasting paper is available, here.

Lord Christopher Monckton read the proposed Copenhagen agreement and concluded that, unless U.S. citizens are able to pressure their government to not sign the agreement at the December 2009 summit, unelected world government and large transfers of wealth from developed countries to undeveloped ones will result. Listen to the rousing conclusion to his 14 October speech here.

Here is evidence from a child’s science project that increased temperatures in the U.S. over the 2oth Century can be attibuted to the urban heat island effect, and not “global warming”. (Large cities cover only a tiny fraction of the area of the Earth.) I urge others to independently replicate and extend this school boy’s experiment and to report the results. The findings of the study also provide a solution for those who remain concerned about warming: Abandon the cities!

For an earlier discussion of this issue, see Steve McIntyre’s 2007 essay “Trends in Peterson 2003″.

The September global mean temperature anomaly was +0.42C, a relatively warm month as the updated results graph in the right column shows. Armstrong was a clear winner for the 2008 year; with nine months of 2009 gone, what are the prospects of Gore winning 2009? With the average temperature anomaly for the year-to-date at +0.23C clearly below both Armstrong’s and Gore’s year-to-date forecasts of +0.28C and +0.33C respectively, Armstrong is looking good to win 2009. For Gore to win 2009 now, the average temperature anomaly for the remaining three months of 2009 would have to equal or exceed +0.535C. This has happened on only two previous occasions in the last 31 years, February to April and May to July 1998, during the warmest part of a strong El Nino cycle.

Result for the first 20 months of the bet, to the end of August 2009, are shown in the graph below the globe image on the top right of this page. Gore has now lost 18 of the 20 months since the “bet” was announced.

Clicking on the graph shows a larger  copy of the graph, including the data, in a separate browser window.  Note also that, at the time of writing, the HubDub prediction market (shown in the second graph) gives Armstrong a 73% chance of winning the bet.

Theclimatebet.com will report monthly results on the climatebet, assuming that Mr. Gore took the bet. Professor Armstrong says it is all part to natural variation that occurs over time. He expects the scientific approach to forecasting will win in the long-run, so the longer the horizon, the greater the chance for Prof. Armstrong to win. Based on simulations of changes over the past 157 years, his chances of winning would be in excess of 62% for the ten-year horizon of the bet. On a monthly basis, he expects it to be slightly in excess of 50%. Mr. Gore believe that we cannot afford to wait because global warming is happening rapidly. Thus, he should find this monthly tracking to be of great interest. For purposes of the bet we assumed that Mr. Gore agreed with the IPCC forecast of 3⁰C rise per century whereas Professor Armstrong forecast no change.

While theclimatet.com focuses on forecasting issues, the forecasts are, of course, affected by the knowledge about causal factors. To date, this literature has been scattered over a wide number of disciplines and a staggering number of journals. Thankfully, a convenient source for the scientific evidence has recently been published: Climate Change Reconsidered: The Report of the Nongovernmental International Panel on Climate Change. In contrast to the IPCC report by the United Nations, there were no political pressures involved in this report – and much of the research was done without funding. You can see many reviews at amazon.com – nearly all highly favorable at present — and much discussion of this book on blogs.

Scott Armstrong presented a paper co-authored with Kesten Green, Andreas Graefe, and Willie Soon at the International Symposium on Forecasting in June that examined some of the lessons for climate policy from evidence-based forecasting. The authors described the lack of scientific long-term forecasts of global temperatures, the impacts of temperature changes, and the effects of policies. The paper explained the need for simple methods and conservative forecasts in the face of uncertainty and complexity and pointed out that simple no-change benchmark forecasts are sufficiently accurate for policy decisions. In contrast, simple causal models with CO₂ as the policy variable are not credible.

Prediction markets for temperatures in three and ten years time agree that the no-change forecast is the more likely outcome than the IPCC 0.03C per annum forecast. Finally, similar (analogous) alarms in the past identified by the authors and others turned out to be false alarms. The slides for the talk are available as a PowerPoint file and as a PDF file.

Written by Ann McElhinney & Phelim McAleer

As appeared on The Climate Depot.

A leading UK lawyer, who represented the parent that sued Al Gore in the British High Court, has laughed off claims by the former vice-president that the judge ruled in his favour. Speaking from London John Day, a senior partner in Malletts Solicitors, said Mr Gore was misrepresenting what the judge had found. Mr Day represented a British parent who sued the UK Ministry of Education when they wanted to distribute and show Mr Gore’s documentary An Inconvenient Truth to every British school child. Read the rest of this entry »

Is carbon dioxide a good causal variable for forecasting global temperature? Have there been alarms in the past similar to the current alarm over dangerous manmade global warming and, if so, what happened? Can rule-based forecasting help forecast global mean temperatures? What do prediction markets reveal?

These questions and more will be answered at a climate forecasting session at the International Symposium on Forecasting presenting work by Green, Armstrong, and Graefe. To be useful, forecasts should be substantially more accurate than those from a simple benchmark method, for example the no-change model. We suggest taking the following self-administered quiz Please write down your estimate and then follow the link to find the answer. Read the rest of this entry »