The Global Warming Challenge

Evidence-based forecasting for climate change

Archive for the ‘kesten green’ Category

Gore bet looks vulnerable with less than one-third to run

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The September 2014 data showed a small lift in the global mean temperature to an anomaly of 0.3°C. Still a win for the month to Professor Armstrong and the Green, Armstrong, and Soon no-change forecast, temperatures have been cooler than Mr Gore and the IPCC’s alarming projection for 20 months in a row. Overall, global mean temperatures have come in cooler than the alarmist projection 80 percent of the time since the beginning of the bet nearly seven years ago.

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October 22nd, 2014 at 6:35 am

Armstrong and Green on climate models in NIPCC’s Climate Change Reconsidered II

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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 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.

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December 21st, 2013 at 11:32 pm

Financial Post gives voice to scientific climate forecasting

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“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.

New scientific report on climate change

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The Nongovernmental International Panel on Climate Change (NIPCC) has released a new report on the science of climate change: Climate Change Reconsidered II: Physical Science. The key takeaway messages are (1) the human impact on climate is very small and (2) any change in temperatures that might be occurring or will occur in the future is so small that it will not be noticed against the climate’s entirely natural variability.

As part of the NIPCC’s process for preparing this volume, scores of scientists from around the world evaluated the most up-to-date research on the physical science of climate change. This report is at least as comprehensive and authoritative as the reports of the United Nations-funded Intergovernmental Panel on Climate Change (IPCC) … and the NIPCC report is faithful to the scientific method. Whereas the mission of the IPCC is to find a human impact on climate change and thus justify government control of greenhouse gas emissions and our economy, the NIPCC has no agenda other than discovering the truth about climate change.

Section 1.1.1 of the report addresses forecasting principles and methods, and was co-authored by J Scott Armstrong and Kesten C Green. It is on p.14 of the Chapter 1 of the report, which is available here.

Cooler April another challenge for warming alarmists

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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.

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May 7th, 2013 at 2:11 am

Armstrong wins two-thirds of months at halfway point of 10-year bet

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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].

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January 10th, 2013 at 5:30 am

Where’s the warming, Al?

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The warming alarmist Met Office’s own figures, released without fanfare last week, show no global warming for 16 years. Does that mean we have had 16 years of “dangerous manmade global equilibrity”? Or should that be, 16 years of “beneficial manmade global temperateness”? Who’d have guessed? As readers of these pages will know, this is just what Kesten Green, Scott Armstrong, and Willie Soon found to be the best forecast of global mean temperatures in their paper titled “Validity of climate change forecasting for public policy decision making“: No change. This is also the forecast that Scott Armstrong has issued to challenge Al Gore’s forecast of alarming manmade warming. The Mail‘s article is here, and their temperature graph is below. Further discussion is provided by the Global Warming Policy Foundation, here.

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October 16th, 2012 at 3:57 am

Fun Climate Forecasting Quiz

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Test your climate forecasting skills: It’s anonymous, and fun!

Go straight to the Quiz on the page here, make your forecasts for the two 25-year periods offline, then check the outcome and grade your response here.

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.

Polar bears thrive: A surprise for Boxer Committee, which preferred alarm to scientific forecasts

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In an article titled “Healthy polar bear count confounds doomsayers,” Paul Waldie in The Globe and Mail reported on 4 April…

“The number of bears along the western shore of Hudson Bay, believed to be among the most threatened bear subpopulations, stands at 1,013 and could be even higher, according to the results of an aerial survey released Wednesday by the Government of Nunavut. That’s 66 per cent higher than estimates by other researchers who forecasted the numbers would fall to as low as 610 because of warming temperatures that melt ice faster and ruin bears’ ability to hunt. The Hudson Bay region, which straddles Nunavut and Manitoba, is critical because it’s considered a bellwether for how polar bears are doing elsewhere in the Arctic.”

This report will come as no surprise to followers of, where we prefer scientific forecasting to politically motivated alarmism. For a recap on scientific forecasting’s contribution to the polar bear population question, Scott Armstrong’s letter 2008 to Senator Barbara Boxer, who chaired a hearing on the issue, is here.

The 2008 paper on polar bear population forecasting, by Scott Armstrong, Kesten Green, and Willie Soon, is available here.

To see the rest of Paul Waldie’s report on the happy state of the polar bear population in 2012, see here.

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April 9th, 2012 at 7:26 am

Gore trails after 4 lively years of warming bet

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The Gore-Armstrong climate bet has now completed four-tenths of its ten-year race with Scott Armstrong in the lead. The latest graph and data are available to the right. Click on the graph to show a larger version of the graph with the data. You will see that we finished 2011 with average global temperatures for the year slightly lower than the bet benchmark year of 2007.

While Professor Armstrong is confident that his no-change forecasting method is better than Gore and the IPCC’s +0.03C per annum unscientific extrapolation, ten years is short in climate terms, and Mr Gore is still in with a chance. To provide some perspective, climatologists sometimes use seven years as the duration of a climate period. Over the last seven years, the UAH global temperature anomaly series has trended upwards at a rate of 0.008C per year. The solar magnetic activity cycle has a period of about 11 year. Over the last 11 years, the temperature series has had a trend of +0.019C per year. The former trend is much closer to Prof Armstrong’s no-change forecast than it is to Mr Gore’s extrapolation, but the latter is somewhat closer to Mr Gore’s extrapolation. The trend for the entire 33 year period of the UAH temperature series, at +0.0138C per annum, marginally favors Prof Armstrong’s forecasting method and suggests that there is no reason for alarm. will continue to report monthly results on The Climate Bet, assuming that Mr. Gore took the bet. Professor Armstrong maintains that changes in temperature are natural variations that occur over time. He expects the scientific approach to forecasting will win in the long-run, though he realizes the 10 years of the bet may not be long enough. When he proposed the bet, simulations of temperature changes over the previous 157 years indicated that his chances of winning would be somewhat greater than 62%.

An article by Kesten Green, Scott Armstrong, and Willie Soon in the International Journal of Forecasting explains the reasons behind Professor Armstrong’s choice of the no-change model for forecasting global average temperatures. It is available here.

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January 10th, 2012 at 4:16 am