The Global Warming Challenge

Evidence-based forecasting for climate change

Archive for January, 2010

Gore loses the first 2 years of the climate bet to Armstrong’s scientific forecast

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What if Mr. Gore had accepted Professor Armstrong’s proposed ten-year bet on climate change in 2007? Gore said that the temperature would go up while Armstrong predicted it would not change from the 2007 average. We assumed a relatively conservative prediction from Mr. Gore of a 0.03 degrees Centigrade increase per year: the central projection of the U.N.’s Intergovernmental Panel on Climate Change.

Over the years 2008 and 2009, Mr Gore’s forecast was closer than Professor Armstrong’s to the actual monthly temperature in only four of the 24 months. Put another way Mr Gore’s forecast was 0.26 degrees too warm in 2008 and 0.08 degrees in 2009, whereas Professor Armstrong’s was 0.23 degrees too warm in 2008 and 0.02 degrees to warm in 2009.

We use the University of Alabama at Huntsville’s satellite measure of the global lower atmosphere temperature anomaly as our actual temperature in order to avoid the problems identified by researchers and, more recently, the release of the “Climategate” emails, with the Hadley Centre series used by the IPCC.

Professor Armstrong said that one must be cautious about small samples. The amount of variability in annual temperature is high relative to the predicted change, so Armstrong said that he expects to lose in some years. As shown by a 150-year simulation of the bet, he said that he had only a bit better than 50% chance of winning a given year, but this jumps to nearly 70% for ten years. Armstrong said, “it is about as certain as one can be in forecasting that I would win if the bet were for 100 years, but I wanted to see what would happen, so I proposed only ten years.”

You can follow the bet on a monthly basis here at theclimatebet.com. In addition you can see what one betting market expects to happen.

Written by admin

January 31st, 2010 at 10:54 am

Posted in Uncategorized