After spiking in January, temperatures in April were again well below the 2007 average that is Scott Armstrong’s forecast. (See the updated chart to the right for the state of the bet.) Over the duration of the 64 months to date of the bet, temperatures have been greater than Mr Gore’s IPCC-based warming forecast for 15 months or less than 23% of the time. In contrast, temperatures have been less than Professor Armstrong’s evidence-based forecasts for 36 months or more than 56% of the time. None of the forecasts was exactly equal to the actual temperature. The results support the contention that Mr Gore and the IPCC’s dangerous warming forecasts are insufficiently conservative given the state of knowledge about climate, and that the Green, Armstrong, and Soon (2009) no-change model provides a better representation of the considerable uncertainty that exists.
The latest, March 2013, global mean temperature data from UAH is now plotted on the Climate Bet Graph at right. The temperature anomaly was the same as it was in February and was again cooler than Scott Armstrong’s no-change forecast. Overall, Al Gore’s IPCC “bet” of warming of 0.03°C per annum has been 18% less accurate than the no-change forecast. Over the 63-month life of the bet to date, on the basis of cumulative absolute error, Al Gore’s alarmist forecast has been the better bet for the 8 month period ending January 2011 only.
Bob Carter, Willie Soon, and William Briggs describe the evidence that changes in radiation from the Sun are the major source of changes in the Earth’s climate in a new article in Quadrant. The claim may seem uncontroversial, but global warming alarmists argue that human emissions of carbon dioxide have such a big effect that they dominate solar changes and are inexorably and dangerously boosting global mean temperatures. The Climate Bet is a test of these hypotheses, with Scott Armstrong “betting” on unpredictable changes in solar radiation and Al Gore on CO2-induced warming… and you know how that has been going.
As we’ve written before, trends appear to emerge in the data, then reverse, on all timescales. January 2013′s relative warmth turned out to be a one-month spike, with temperatures in February again below the 2007 global average temperature. Since the first month of Scott Armstrong’s “bet” with Al Gore, the UAH monthly temperature anomaly has been cooler than the 2007 average for 34 out of the 62 months. In other words, to date 55% of months have been cooler
A jump in global mean temperatures of 0.3°C from December 2012 to January 2013 has helped to keep the bet alive as it enters the second lustrum of its 10-year term. To date, Professor Armstrong’s naive forecast has been more accurate for 40 months out of 61 and has been nearly 13% more accurate overall.
Of the first 60 months of the 120 month (10 year) Climate Bet, Scott Armstrong’s naive model forecast* of no change in global average temperatures has been closer to the actual temperature than Al Gore’s IPCC-orignated 3°C per century warming forecast for 40 months. The updated Climate Bet Graph is to the right.
Mr Gore and much of the media are concerned about global warming. They should be relieved to learn that over the last five years (2008 to 2012) temperatures were flat or down from the previous month for 62% of months. The year 2012 ended with the global mean temperature for December the same as for the base year for the bet, 2007.
We calculate from the Hadley Center’s global average annual temperature estimates from 1850 to 2012 that the next five years would have to witness a rate of annual average temperature increase greater than 78% of previous five-year sequences in order for Mr Gore to win the bet. Perhaps, like the UK Met Office, he would like to reconsider his forecast.
*To learn more about the naive model, and the performance of no-change forecasts compared to the IPCC’s “forecasts”, see these papers:
Green, K. C., Armstrong, J. S., & Soon, W. (2009). Validity of climate change forecasting for public policy decision making. International Journal of Forecasting, 25, 826–832.
Green, K. C., Soon, W., & Armstrong, J. S. (2013). Evidence-based forecasting for climate change. [Working paper - not for citation].
November 2012 global mean temperature data from the University of Alabama at Huntsville is out. The chart to the right displays the up-to-date figures. After 11 straight months of temperatures closer to Armstrong’s no-change forecast, in September and October temps were closer to Mr Gore’s IPCC-warming forecast. The brief warm spell didn’t last, however, and the global mean temperature in November is once again closer to no-change than to alarming.
The New York Times warns civilization likely to end due to manmade warming – Professor Armstrong tries to avert panic.
On November 24, 2012, The New York Times published an article titled “Is this the End?,” which warned that manmade global warming is likely to destroy our civilization. The article was published nine days after the NYT published Cass Sunstein’s article advocating that policies on dangerous manmade global warming should be based on cost-benefit analyses, that the government had calculated a net benefit for costly policies, and that Ronald Reagan once agreed with a cost-benefit analysis. I was unable to contact Professor Sunstein to find the sources of the “cost-benefit analyses.” In an effort to calm panic-stricken readers, I wrote a Letter to the Editor at The New York Times revealing that while cost-benefit analysis is indeed the proper method, none has shown likely net harm arising from global warming. Evidence-based forecasts of dangerous warming and of the effects of alternative policies are missing. Strangely, my evidence-based forecasts that our civilization is not threatened by dangerous warming did not meet the NYT criteria of “All the news that’s fit to print.” If you know any NYT readers, please inform them that they are safe.
Wall Street Journal readers were spared panic. They had read No Need to Panic About Global Warming in January 2012.
Scott Armstrong’s letter responding to Margaret Wertheim’s rather strange attempt to associate skepticism over alarming forecasts of global warming with pseudoscience, was published in the Wall Street Journal on 2 November 2012. The online version is available here, and the text of the letter was as follows.
Regarding Margaret Wertheim’s “strange and dangerous” view of science displayed in her review of Michael D. Gordin’s “The Pseudoscience Wars” (Bookshelf, Oct. 23): Science isn’t based on the opinions of scientists. Rather it is a process that tests reasonable alternative hypotheses and describes this so that others can challenge the findings. Discoveries arising from this process often seem absurd to scientists when initially presented. Many Nobel Prize winners have described the negative reactions to their most important findings.
It seems odd then that Ms. Wertheim should choose the Immanuel Velikovsky case to illustrate pseudoscience. Velikovsky provided full disclosure of his hypothesis and asked other scientists to test predictions from his hypothesis. It was other scientists who acted in an unscientific manner, with ad hominem attacks and attempts to stop his views from being heard. Ms. Wertheim apparently believes these responses were appropriate and by extension, she believes that hypotheses that humans have little influence on global average temperatures should not be heard or tested. She even suggests that scientists who propose such hypotheses aren’t credible because some of them received funding from sources that don’t meet with her approval.
Prof. J. Scott Armstrong
University of Pennsylvania
With only two months to go until the half-way point of Scott Armstrong’s notional bet with Al Gore, it is impossible for Mr Gore to take the half-time lead. He would have to be perfectly accurate for the next two months, as well as have been perfectly accurate for the six just gone in order to do so. The latest chart showing the progress of the bet to October 2012 is to the right. Click on it for a larger image.