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October 2015 saw the warmest global average temperature for nearly three years at 0.43°C above the 1981-2010 average. November followed with an “anomaly” of 0.33°C.
The put the figures into the slightly longer term context of The Climate Bet’s nearly 8 years to-date, the first three months of 2010 were all warmer than the October just gone. But how consistent are the figures with the IPCC-Al Gore dangerous manmade global warming projection?
While the October figure on its own is consistent with the +3°C per century IPCC “business as usual” projection applied to the 2007 bet base year average—it was 0.02°C warmer—that has only happened in 14 of the 95, or 15%, of the months of the bet, to date. The chance that a warmer than projected temperature would happen so few times by chance with an unbiased forecast is one-in-1,612,577,151,852.
For an explanation of why the IPCC projections are such bad forecasts, see Kesten Green’s guest post “Is climate forecasting immune from Occam’s razor” on the Watts Up With That site, here.
You might be forgiven for wondering whether such a difference holds any meaning for you. Not only are the month-to-month and year-to-year variations in global average temperature tiny, the local temperature variations that you are experiencing are quite likely to be opposite in direction. For example, the UAH global temperature anomaly increased from 0.18°C in July to 0.28°C in August. Over Australia the anomaly average stayed the same at -0.22°C, and over the 48 contiguous U.S. states the average fell from 0.16°C to 0.09°C. Both Poles experienced below average temperatures in August of -0.10°C in the northern polar region and -0.61°C in the southern. And these broad regions are hardly local!
At 0.18°C, July’s global average temperature anomaly is very close to the 2007 average of 0.16°C that Scott Armstrong is betting is the better forecast than Mr Gore’s dangerous global warming “tipping point” forecast. The latest chart (click on the small chart image to the right) shows that temperatures have seesawed over the 91 months of the bet so far. An inspection of the vertical (temperature) axis indicates that the seesawing of the monthly global temperature anomaly has been rather gentle, barely exceeding a third of a degree either side of the 2007 annual average.
Scott Armstrong was interviewed for the documentary, The Global Warming War. Released late last year, the movie provides a contrast with Merchants of Doubt in both style and substance. See The Global Warming War-Scott’s clips (2.5 minutes).
The LA Times letters editor has apparently decided that they know The Truth in scientific matters and will not let anything else bescmirch their pages. We will let someone else check the Times record in this endeavour. In the meantime, Scott Armstrong has written an op-ed asking who benefits from such a policy. His article, titled “Los Angeles Times endorses censorship with ban on letters from climate skeptics” is here.
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.
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].
The story of sea ice in the “other” Arctic, the Antarctic, seems to be largely untold. It turns out the extent of the Antarctic sea ice sheet has reached a record high. At least it is a record since satellite measurements began in 1979. Yes, I know, that is a short period and so not much of a record, but it is the same period that is used as the basis for Arctic sea ice record claims. Similarly, consistency requires that if one claims that Arctic ice has trended down then one must admit that Antarctic sea ice has trended up. For a chart of the time series and discussion on implications for temperatures, see the Real Science page here.
Test your climate forecasting skills: It’s anonymous, and fun!
To learn about the latest developments in climate forecasting, read the draft paper by Kesten Green, Scott Armstrong, and Willie Soon from the recent International Symposium on Forecasting in Boston (June 2012). The link to the paper is here, and supporting materials are towards the bottom of the page.
With a spell of some warmer than average weather over the last three months, the notional Al Gore’s bet on the IPCC’s .03C per annum warming forecast has been on the money for 23 out of 54 weeks. On the other hand, Scott Armstrong’s bet that temperatures would not change from the 2007 average in any predictable way has been on the money for the other 31 weeks, thus bettering the Gore hit rate by 35%.