Archive for the ‘forecasting’ Category
We’ve updated the Climate Bet graph on the right with the global average temperature for August. The picture seems clear to us: there is no trend. Not surprisingly then, the projected 0.03°C per year increase that the IPCC and Mr Gore (who expected a tipping point and dangerously warming temperatures) thought was likely on the low side has been equaled or exceeded only sixteen times in the 80 month life of the bet, so far. In contrast, monthly temperatures have come in lower than Professor Armstrong’s bet on no-change for 55% of months.
For 21 months straight, global mean temperatures have been below the 3°C per century increase projected by the IPCC, and Mr Gore’s forecast turning point is nowhere to be seen. We wonder whether Mr Gore’s investment predictions in his August 6 op-ed in the London Financial Times are of the same caliber. For the latest temperature data and progress on the Climate Bet, see the updated chart to the right.
Since we started monitoring the Gore-Armstrong bet back in 2008, global mean temperatures have only rarely been as warm or warmer than Mr Gore and the IPCC’s +0.03 °C per year warming forecast would have had us believe. How rarely? Well, roughly one-month-in-five, or 21% of the 77 months to date. As we’ve pointed out before, one would expect the figure to be 50% if the Gore/IPCC forecasts were unbiased. Mr Gore must be very unlucky, because the chances that so few months would turn out to be as warm or warmer than unbiased forecasts is less than one-in-eight-million.
But wait, Mr Gore and the IPCC warned us that there was more chance that temperatures would be higher than their forecasts, than that they would be lower. In other words, they claimed their forecasts were biased toward slower warming than the rapid warming they really believed would occur. We haven’t calculated the vanishingly small odds that global temperatures would turn out to be so uninclined to warm taking into account the declared downward bias in their forecasts, but we suspect that Mr Gore and the IPCC have been feeling that the Earth has let them down.
For keen followers, the latest month of The Bet, May 2014, is shown in the chart on the right.
Much has been made of the claim that there is an overwhelming consensus of scientific opinion that we will suffer dangerous manmade global warming during the 21st Century. Putting aside the unscientific and rather desparate nature of resorting to a vote to decide how the Earth’s climate will behave during the current century and beyond, is it true? In their Wall Street Journal op-ed of May 26, 2014, Joseph Bast and Roy Spencer examine the evidence, and shred the claim of consensus on dangerous warming in it various forms. Their op-ed is also available here.
With April’s temperature another to fall below the no-change-from-2007 line, Al Gore’s tipping point continues to elude us. The errors from the Gore stand-in forecast (the IPCC’s +0.03°C per year) are now 27% larger than the errors from Armstrong’s no-change forecasts. The Gore error’s have been so bad, that the contrary hypothesis of natural global cooling would have been a much better bet. Yes, the errors from forecasting temperatures would decline at 0.01°C per year would have been 17% smaller than Mr Gore’s errors! Click on the chart on the right for the latest data on the bet.
The average global temperature for the first quarter of 2014 was less than 0.01°C different from Professor Armstrong’s no-trend forecast. With 75 months of data now in, we wondered whether there was any evidence of bias in Professor Armstrong’s or Al Gore’s forecasts. We found that there was. Both Armstrong’s and Gore’s forecasts appear to have a bias toward forecasting temperatures that are warmer than the measured temperatures. In the case of Scott Armstrong’s no-trend forecasts, they have to date averaged 0.02C warmer than the recorded temperature. In the case of Al Gore’s IPCC alarming warming forecasts, they have averaged 0.12C warmer. We think policy makers should prefer less-biased forecasts. The updated Climate Bet graph is to the right.
With 74 months of the Armstrong-Gore bet behind us and 46 months left to go, global mean temperatures have gone nowhere. That, of course, is the no-trend forecast that is the basis of Professor Armstrong’s bet. Mr Gore on the other hand claimed temperatures would go up, dangerously. In fact, most months of the bet (57%) have seen temperatures flat or down from the previous month. Professor Armstrong’s conservative forecast has been more accurate than Mr Gore’s alarmist forecast for nearly 69% of months so far.
Unlike Al Gore, Nobel laureate Brian Schmidt is willing to bet on what global mean temperatures will be in 20 years time, presumably with his own money. Schmidt’s offer to bet was in response to Australian Prime Minister Tony Abbott’s business advisor Maurice Newman’s skepticism over the IPCC’s alarming projections.
But reading on, Prof Schmidt, and the other warming alarmists who suddenly popped up saying “me too” are not so brave. As Jo Nova explains, they are only willing to bet that temperatures will be warmer, not that they will be dangerously warmer… they want the rest of us to pay for that bet.
Mostly down. In the course of the 72 months of the bet to date, the global mean temperature fell or remained flat compared to the previous month for 41 months, or 57% of the time. (In case you’re wondering, the UAH series records only 2 occasions over this period on which the temperature did not change from the previous month.)
We’re not sure how the ups-and-downs of the global temperature over these last six years accord with what Mr Gore had in mind when he issued his warning of an immanent and catastophic “tipping point”, but we know that his chances of winning the Climate Bet against the no-trend forecast proposed by Professor Armstrong have receded as the life of The Bet has progressed.
See the chart to the right with the latest (December 2013) data.
A summary of the critique of the use of complex mathematical models for forecasting long term climate change by Kesten Green, Scott Armstrong, and Willie Soon is published in the Nongovernmental Panel on Climate Change’s Climate Change Reconsidered II: Physical Science (2013).
The reference is as follows, and links to the relevant section and to the entire NIPCC report are available from the Global Warming Audit pages of the forecastingprinciples.com site, here.
Armstrong, J. S., & Green, K. C. (2013). Global climate models and their limitations: Model simulation and forecasting – Methods and principles. pp. 14-17 in Idso, C. D., Carter, R. M., & Singer, S. F. (Eds.), Climate Change Reconsidered II: Physical Science. Chicago, IL: The Heartland Institute.