Archive for the ‘the challenge’ Category
With October 2013′s global mean temperature data in, we now have 70 months of evidence on the accuracy of Mr Gore and the IPCC’s alarming warming forecast of temperatures increasing at a rate of 0.03ºC per annum. If Mr Gore’s forecast were valid and unbiased, we would expect actual temperatures to be higher than his forecast roughly half of the time and lower roughly half of the time. We checked the record of The Bet. It turns out that, to date, the actual global mean temperature has been higher than Mr Gore’s forecast less than one-quarter (23%) of the time. By contrast, the measured temperature has been warmer than the no-change benchmark, Professor Armstrong’s bet, 46% percent of the time; very close to the ideal of 50%. The updated chart is to the right.
“There are no scientific forecasts of dangerous global warming” shouts a new article in the Financial Post. Readers of this blog know that already, but will likely want to read what the op-ed titled “Climate forecast: All’s well, despite what the IPCC says” by Kesten Green, Scott Armstrong, and Willie Soon has to say about the implications for government policy. It has already attracted lively discussion. The article is here.
The authors claim to provide the only scientific forecast of long-term climate, namely the naive no-change or no-trend forecast that is the basis of Professor Armstrong’s notional bet with Mr Gore. The forecast was originally published in 2009, and the International Journal of Forecasting article can be found here. The authors’ current working paper investigating possible improvements to climate forecasting for policy makers is here.
At 0.16°C, the August 2013 global average temperature anomaly is again below the no-change forecast of 0.208°C. For the 68 months of the bet now behind us, the average temperature has been equal to or below the no-change forecasts for 38 months or 56% of the time. For the latest data and chart on the Armstrong-Gore climate bet, click on the updated chart in the column to the right.
The global average temperature anomaly was below the 2007 average again in July 2013 after a warmer June. Does the average temperature seem to go up-and-down a lot to you? Well, it turns out that the correlation between the change in the average monthly temperature and the change in the previous month is negative (-0.3) over the period relevant to the climate bet, 2007-to-date. In other words, an increase in the monthly temperature anomaly tends to be followed by a decrease the next month, and vice versa. As folks (and the no-change forecast) say, the more things change, the more they stay the same. The latest Climate Bet chart is posted to the right.
We have belatedly updated the Armstrong-Gore bet graph, to the right. Those of you with keen eyes and good memories may notice some differences in the plot of the temperature series. The UAH global mean temperature anomaly series has been revised to Version 5.6. Information about the revision is available here.
With the release of the June figure, for the second time in 2013 Al Gore’s putative global mean temperature forecast was more accurate than the no-change forecast, .005°C more accurate.
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.
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.
Adjustments to allow for a drifting satellite have found UAH temperatures to be flatter than previously estimated. As a consequence, Armstrong’s bet is safer than before. Gore’s forecast errors to date are 16% larger than the errors from Armstrong’s no-change forecast, and the no-change forecast of global mean temperatures has so far been more accurate than the Gore/IPCC forecast for 67% of the months covered by the bet. For the latest month (September 2012) and revised series, see the updated chart in the right column.