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The Global Warming Challenge
Evidence-based forecasting for climate change
(Updated 9th of March 2023)
Forty-ﬁve Aussie summers: Is there a trend in temperatures?
The global mean UAH lower troposphere temperature anomaly for February 2023 was 0.08ºC,
which was closer to the Green, Armstrong, and Soon no-trend forecast of 0.023ºC (2007 average)
than it was to the Gore/IPCC 3ºC-per-century “dangerous warming” (post “turning point”)
extrapolation. The cumulative absolute error of the dangerous warming extrapolation is now, after
182 months of The Climate Bet, more than 12 percent greater than the no-trend forecast.
February is the high-summer month in the Southern Hemisphere, so now that the southern summer
of 2022/23 is over, I’ve updated the Australian high-summer temperature chart, which can be seen
Australia’s February 2023 UAH temperature anomaly turned out to be -0.12ºC. In other words, for
the third year running, cooler than the 30-year average. The chart shows the February data for the
entire period for which satellite temperature readings are available.
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Yea r Anomaly* Armstrong Gore
30.35 0.023 0.406
40.26 0.023 0.408
50.42 0.023 0.411
60.30 0.023 0.413
70.31 0.023 0.416
80.30 0.023 0.418
90.40 0.023 0.421
10 0.38 0.023 0.423
11 0.40 0.023 0.426
12 0.15 0.023 0.428
2021 10.13 0.023 0.431
20.20 0.023 0.433
30.00 0.023 0.436
4-0.05 0.023 0.438
50.09 0.023 0.441
6-0.01 0.023 0.443
70.20 0.023 0.446
80.17 0.023 0.448
90.26 0.023 0.451
10 0.37 0.023 0.453
11 0.09 0.023 0.456
12 0.21 0.023 0.458
2022 10.03 0.023 0.461
20.00 0.023 0.463
30.15 0.023 0.466
40.26 0.023 0.468
50.17 0.023 0.471
60.06 0.023 0.473
70.36 0.023 0.476
80.28 0.023 0.478
90.24 0.023 0.481
*www. nsstc.ua h.edu/ data/msu/ v6.0/tlt/uahncdc_lt_6. 0.txt 10 0.32 0.023 0.483
Updated 9 March 2023 from Version 6.0 as of April 2015; base period revised at beginning of 2021 11 0.17 0.023 0.486
We have recalculated the Bet forecasts and results using the revised series. 12 0.05 0.023 0.488
^Green, Armstrong, & Soon (2009). Vali dity of cli mate change forecasting f or public policy decision making. 2023 1-0.04 0.023 0.491
International Journal of Forecasting, 25( 4), 826-832. https://doi.org/10.1016/j.ijforecast.2009.05.011 20.08 0.023 0.493
Little anomaly in February 2023 global average temperature
(Temperature deviation from 1991-2020 average, in degrees C*)
2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023
GAS 2009^ n o trend (Arm strong) IPCC +3°C/century (Gore) Monthly anomaly Annual anomaly
As after previous summers, inspection of the chart would suggest that estimating a time trend for
the data would be inappropriate, and yet extraordinarily expensive policies have been implement
and more are being proposed in the name of the dangerous global warming hypothesis under the
banner of “net zero” human carbon dioxide emissions.
Is there a trend in the Aussie data that would support the dangerous warming hypothesis as carbon
dioxide emissions have continued to increase that is not obvious to visual inspection?
The short answer is, no.
The OLS regression estimate of the “trend” in the Australian high-summer average temperature
over the 45 years of available satellite readings is a rather doubtful 0.03ºC-per-century.
That is one-hundredth of the rate of warming we have been told by the United Nations
Intergovernmental Panel on Climate Change, and by politicians and the media, that we should be
March the 9th, 2023 at 03:45 pm ACST
2023 starts cool-ish
In this sixteenth year of the extended Climate Bet—in which the forecast of dangerous global
warming is tested against the forecast of no-change, or no-trend—the year has started with the
global temperature anomaly 0.063ºC below the 2007 Bet base year annual average, and 0.040ºC
below the 1991-to-2020 average.
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-2 -1 0 1 2
1980 1990 2000 2010 2020
February UAH temperature anomalies relative to 1991 to 2020 average
Australian High-Summer Temperatures: 1979 to 2023
To date, the global UAH lower troposphere temperature anomaly has been cooler than the no-
change forecast for 36 percent of months, and warmer than the IPCC-Gore 3ºC-per-century
“dangerous” warming projection for 17 percent of months.
The accumulated absolute error of the dangerous warming forecast is now 11.4 percent greater that
the error from forecasting no change relative to the 2007 average. Decision makers have not been
well-served by the IPCC’s dangerous warming forecast.
February the 2nd, 2023 at 04:00 pm ACST
2022 year anomaly 0.174℃ after 0.17℃ in November and
0.05℃ in December
This post addresses the two months of November and December 2022, and the 2022 year.
The month of November 2022’s global anomaly was down from October’s 0.32ºC to 0.17ºC.
December’s was lower again at only 0.05ºC different from the 1991 to 2020 average.
Over land—where people live—the anomaly was -0.06ºC in December. For the US’s 48 contiguous
states, the ﬁgure was -0.21ºC, and for Australia -0.38ºC
The average anomaly for the 2022 year was 0.174ºC compared to the 2007 base-year ﬁgure of
0.023ºC. Over the 15 years of the extended “bet” to date, ﬁve years were warmer than 2022, and
nine were cooler.
Overall, the absolute errors of the “dangerous” global warming projection over the period of The
Bet to date have been 10% larger than the forecast of no-change from the 2007 annual average
January the 4th, 2023 at 11:55 am ACST
Dr John Christy, Distinguished Professor of Atmospheric
Science at UAH, discusses the data on climate and weather
John Christy allays fears on climate, weather, and sea level by confronting claims of worrying new
records and model predictions with data in the excellent video interview, below, recorded in mid-
December. (Play at 1.5x or faster if pressed for time.) December the 22nd, 2022 at 10:50 pm ACST
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Australian climate records: BoM versus RSS versus UAH
In her 25th of November blog post, Jo Nova critiques the CSIRO and Bureau of Meteorology’s State
of the Climate report’s claims of warming over the last decade. She points out that the UAH satellite
data shows no warming over that period—a period over which atmospheric carbon dioxide
increased from 391 to 416 parts per million or one part in 2,404, commensurate with one pace on a
23 minute mile-and-an-eighth or 9 furlong walk.
Nova also recaps with a list of “Five reasons UAH is different (better) to the RSS global
temperature estimates”. Recall that the UAH (University of Alabama at Huntsville) lower
troposphere measure is the one we use for The Climate Bet on these pages.
Jo Nova’s blog entry is online, here.
November the 29th, 2022 at 11:00 am ACST
October global mean temperature anomaly pips up to 0.32℃
The month of October 2022’s global anomaly—i.e., difference from the 1991 to 2020 average—was
0.32ºC. That ﬁgure is closer to the IPCC-Gore +3ºC-per-century projection represented by the red
line in the chart at top than it is to the green line representing the Green, Armstrong, and Soon
(2009) no-change forecast—a “trend” of 0.0ºC per century.
During the 178 months of the extended “bet” so far, that has happened on 67 months, or 38% of
months since 2007. More remarkably, the temperature anomaly has been lower than the no-change
forecast value more than twice as often as it has been above the IPCC-Gore “business as usual”
warming projection: 36% of months compared to 16% of months. One would expect unbiased
forecasts to be lower than the actual ﬁgure roughly half of the time, which suggests that the 3ºC-
per-century warming projection is seriously biased in the warm direction.
Overall, the absolute errors of the “dangerous” global warming projection over the period of The
Bet to date have been 8.6% larger than the forecast of no-change from the 2007 annual average
Despite the evidence, policy makers bizarrely continue to act as though the dangerous warming
projections from the IPCC et al. were credible.
November the 14th, 2022 at 11:30 am ACST
Is CO2 important for climate change?
In a recent paper for the Global Warming Policy Foundation, William Kininmonth explains that
changes in the level of carbon dioxide in the atmosphere from continued industrial activity would
have only a trivial impact on the greenhouse effect, at around +0.2%.
Moreover, that change would be dwarfed—as have the effects of historical and pre-historical
changes in atmospheric CO2 concentrations—by natural changes in the massive movements of heat
from the tropics to the temperate and polar latitudes by means of ocean currents and winds…
changes that may be explained, but which defy policy relevant forecasting.
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The paper by Kininmonth—who was head of the National Climate Centre when he retired from
Australia’s Bureau of Meteorology after nearly 40 years of service—is available from The Global
Warming Policy Foundation’s site (thegwpf.org) or directly by clicking on “Rethinking The
November the 10th, 2022 at 2:30 pm ACST
September anomaly closer to no-change than 3℃ warming
At 0.24ºC, the September UAH lower troposphere global temperature anomaly was closer to the
Green, Armstrong, and Soon (2009) no-trend forecast than it was to the 3.00ºC warming per century
extrapolation of the IPCC: The Climate Bet’s stand in for Al Gore’s 2007 warning of a dangerous
As usual, there was considerable regional variation. Those of us living in Australia, for example, on
average experienced temperatures 0.29ºC below the 30-year average, and southern hemisphere
temperatures over land were equal to the the 30-year September average.
October the 31st, 2022 at 4:00 pm ACST
Global anomaly remained on the warmer side in August
The UAH lower troposphere global temperature anomaly was 0.28ºC in August; slightly down on
July’s ﬁgure of 0.36ºC, and back within the range of the 2007 base year of The Bet.
With the regional August UAH data now available for the warmest month of the Northern
Hemisphere summer (August) available we now have 44 August anomalies for the USA’s 48
contiguous states. Those data are plotted in the chart, below.
Can you see a trend in those US high-summer temperatures?
There is certainly no pattern shouting out of the chart to suggest that 44 years from now
temperatures will be dangerously higher.
Still, to satisfy the curious and pattern-seeking readers, the OLS trend estimated from the available
data is +1.0ºC-per-century.
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September the 27th, 2022 at 3:30 pm ACST
“Corrupted Climate Stations” and why we use UAH measures
Why does The Climate Bet use the University of Alabama’s satellite measurements of lower
troposphere temperature anomalies rather than ofﬁcial sources? We have described the reasons
before (variously below) in this monitor of competing global mean temperature forecasts. The
following describes a recent and thorough update on the state of the ofﬁcial records that conﬁrms
that our original decision to go with the UAH data still holds good.
Anthony Watts of Watts Up With That? climate change site fame has written a new report titled
CORRUPTED CLIMATE STATIONS: The Ofﬁcial U.S. Temperature Record Remains Fatally
Flawed (Heartland, 2022) as a followup to his 2009 report, Is the U.S. Surface Temperature Record
In his results and ﬁndings section, the author states:
The 2009 report found 89 percent of stations were unacceptable by NOAA’s own standards.
The 2022 report found an even greater percentage of stations—approximately 96 percent—
are sited unacceptably. The ofﬁcial U.S. temperature record, which was shown in 2009 to be
heat-biased due to poor siting issues, appears to be even more biased in 2022.
And in the conclusions and recommendations sections:
Watts and his fellow authors found a slight warming trend when examining temperature data
from unperturbed stations, which cleaved closely to the ﬁndings of the University of
Alabama-Huntsville’s satellite-derived temperature record. This warming trend… is
approximately half the claimed rate of increase promoted by many in the climate science
The report was published by The Heartland Institute, and is available for downloading (warning, it
is a large ﬁle) from their media advisory page, here.
August the 17th, 2022 at 4:00 pm ACST
July temperature anomalies up on average
July’s UAH global temperature anomaly (lower troposphere) was 0.36ºC; up from June’s near-
average ﬁgure of 0.06ºC and closer to the 3ºC warming per century extrapolation of the IPCC than
to the Green, Armstrong, and Soon (2009) no-trend forecast.
After 175 months of “The (extended) Bet” however, the cumulative relative absolute error—the
Bet’s announced criterion for choosing the winner—remains in favour of the no-trend forecast: the
cumulative absolute error of the warming extrapolation is currently 10 percent greater than that of
the no-trend forecast.
Another measure that could be used is the OLS trend from The Bet base year (2007) average
anomaly of 0.023ºC. That trend ﬁgure to July 2022 was 1.45ºC per century—closer to 0ºC than to
3ºC. Considering only where people live (on land) the trend ﬁgure was 0.83ºC per century.
August the 10th, 2022 at 5:00 pm ACST
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Global temperature anomaly down again in June
June was cooler over much of the globe at 0.06ºC above the 1991-to-2020 global average UAH
lower troposphere temperature reading, and little different from 2007 (Bet base year) average
anomaly of 0.02ºC.
July the 11th, 2022 at 5:00 pm ACST
May anomaly 0.17ºC, down from April
At at 0.17ºC above the 1991 to 2020 average, the UAH lower troposphere global temperature
anomaly for May was warmer than 63 percent of months since January 2007 and hence the same or
cooler than 37 percent of months. The ﬁgure was among the warmest 16 percent of months since
satellite records began in late-1978.
June the 7th, 2022 at 2:45 pm ACST
Global anomaly +0.26ºC, Australia +0.60ºC, US48 -0.26ºC
The UAH lower troposphere global temperature anomaly for April was the warmest it has been for
six months at +0.26ºC. The ﬁgure was among the warmest 10 percent of months since satellite
Australia’s mid-autumn month anomaly was the warmest anomaly for the island continent for nine
months—and among the warmest 20 percent of the 44 April ﬁgures since satellite records began—
though concerns here were with too much rain, and ﬂooding, rather than too much warmth. The US
48 contiguous states’ mid-spring anomaly, on the other hand, was the coolest anomaly for eleven
months, and among the coolest third of April ﬁgures since satellite records began.
May the 18th, 2022 at 4:30 pm ACST
What’s been happening to temperatures where people live?
The University of Alabama at Huntsville’s temperature anomaly readings are available by region,
and for land and ocean separately for those regions. The subject of The Climate Bet is the global
average lower troposphere temperature, but given that The Bet was proposed in response to Al
Gore’s 2007 warning of a dangerous and imminent “tipping point” and the IPCC’s dangerous
warming alarm, a look at how dangerous temperatures have been in practice on land in places
where people live is relevant.
The table below summarises what has happened to temperatures over land by region since 2007.
First note that monthly temperatures over land across the whole globe have mostly (85.4 percent of
months) fallen within the 2007 range, and that temperature have more often been cooler (9.9
percent) than warmer (4.7 percent) than 2007 temperatures.
Given the up and down nature of the monthly temperature anomalies, ﬁtting a trend and expecting it
to persist for decades seems either heroic or foolish. But extrapolation is the underlying rationale for
the global warming alarm, and so the table includes OLS ﬁts of the “trend” from 2007 for each of
the regions and for the globe. The OLS trend ﬁt from the 2007 origin for the global land ﬁgures is
0.76ºC per century, much lower than the IPCC’s (1992) 3ºC-per-century warming alarm projection,
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and closer to the Green, Armstrong, and Soon (2009) no-change forecast (a “trend” of 0.0ºC per
century). The measure that we prefer—the relative absolute error—is in the rightmost column of the
table. On that basis, the error from the IPCC’s “business as usual” projection—the basis of costly
net-zero etc. “climate” policies—at 1.31 is 31 percent greater than the no-change forecast.
Of the land areas of the two hemispheres, the Northern Hemisphere with 87.2 percent of the world’s
population experienced cooler than 2007 temperatures six times more frequently than warmer than
2007 temperatures. The error of the warming forecast was 20 percent larger than the no-trend
forecast, on average, for people north of the equator.
Nearly two-thirds (65.5 percent) of the world’s population live, on land, in the northern exotropics
(north of 20ºN). People in the northern exotropics experienced cooler than 2007 temperatures more
than seven times more often warmer than 2007 temperatures, which occurred on only 3.5 percent
(six) of the 171 months since 2007.
Most of the rest of the world’s people (30.6 percent) live in the tropics, the only one of the three-
way divisions of the Earth’s land surface that experienced more warmer than cooler than 2007
temperature months. The OLS trend estimate is, just, closer to the IPCC’s (1992) 3ºC-per-century
warming alarm projection than it is to no-trend at 1.64ºC-per-century warming, and the warming
projection error was 4 percent smaller than the no-trend (no change) error.
Finally, during the 171 months since 2007, the 48 contiguous U.S. states experienced temperatures
within the 2007 range 91.2 percent of the time, and nearly three-times as many cooler months than
warmer months. The OLS trend was 0.80ºC-per-century cooling.
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April the 29th, 2022 at 6:00 pm ACST
After 171 months of The Climate Bet, alarming warming
projection error is 10% greater than no-change error
Fourteen years and three months have passed since the beginning of the period over which The
Climate Bet is being assessed. The latest, March 2022, global temperature anomaly was 0.15ºC, up
slightly from the previous month’s, slightly below average, revised ﬁgure of -0.01ºC.
To date, the global temperature anomaly has been closer to the IPCC 3ºC-per-century warming
projection than to the no-change forecast for 63 months—or nearly 37 percent—of the 171 months.
The cumulative relative absolute error for the warming projection was 9.9 percent.
April the 25th, 2022 at 5:00 pm ACST
Australian high summer temperature trend to 2022
Back in October (below), I had a look at the trends in temperatures in the typically hottest month in
the US (August) and in Australia (February). High-summer temperatures in both countries can be
extreme and, when higher than average, are often reported as evidence supporting the dangerous
manmade global warming hypothesis.
With February 2022’s UAH data available and with claims by some that the major ﬂooding in
Queensland and NSW during that month were the product of a dangerously warming world—even
though the February global temperature turned out to be equal to the 1991 to 2020 average—it’s
time to update the Australian summer trend record with the 44th observation.
Australia’s February 2022 anomaly turned out to be -0.5ºC. In other words, half a degree cooler
than the 30-year average. The chart below shows the February data for the entire period for which
satellite temperature readings are available.
In the absence of the hypothesis, reported as fact, that the world—including and perhaps especially
Australia—has been warming dangerously due to increasing atmospheric carbon dioxide
concentrations from human activity, inspection of the chart would suggest that estimating a time
trend for the data would be inappropriate.
Extraordinarily expensive policies have, however, been implement and more are being proposed in
the name of the hypothesis under the banner of “net zero,” and so I have updated the Aussie high-
summer temperature trend estimate to formally assess whether or not it supports the dangerous
manmade global warming hypothesis, and whether there is evidence of a dangerously warming
Australia in particular.
The OLS regression estimate of the trend in the Australian high-summer average temperature over
the 44 years of available satellite readings is 0.025ºC per century.
That is less than one-hundredth of the rate of warming we have been told by the United Nations
Intergovernmental Panel on Climate Change, and by politicians and the media, that we should be
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With a relationship between the passage of time—and by implication the increasing concentrations
of carbon dioxide—and temperature so weak, it is not surprising that the statistical association as
measured by the R-squared is 0.0000.
March the 18th, 2022 at 4:00 pm ACST
2022 continues to be… average
Last month I noted that January’s UAH global temperature anomaly was only trivially different
from the long run—1991 to 2020—average at 0.03ºC. The latest month’s (February’s) ﬁgure was
bang on average at 0.00ºC.
The 2022 ﬁgures are consistent with the Green, Armstrong, and Soon (2009) no-trend forecast,
which—for the purpose of the Climate Bet—is the Bet’s base-year (2007) average of 0.024ºC.
In contrast, the 3ºC-per-century warming projection of the IPCC—standing in for Mr Gore’s failure
to quantify his 2007 “tipping point” alarm—projected the anomaly would be 0.463ºC in February.
In the next few days, I’ll take a look at the updated trend in Australian high-summer temperatures.
March the 15th, 2022 at 2:45 pm ACST
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-2 -1 0 1 2
1980 1990 2000 2010 2020
(February UAH temperature anomolies relative to 1991 to 2020 average)
Australian High-Summer Temperatures: 1979 to 2022
Latest evaluation of adjustments to ofﬁcial temperature record
Over recent decades there have been a number of independent evaluations of the adjustments that
are made to the individual raw weather station readings in order to derive the ofﬁcial global
temperature record that is used to support claims of dangerous manmade global warming. The latest
and most comprehensive—by Peter O’Neill and sixteen co-authors, published on February 8 in the
journal Atmosphere—has the rather dry title of “Evaluation of the Homogenization Adjustments
Applied to European Temperature Records in the Global Historical Climatology Network Dataset.”
The abstract of the paper states:
A remarkable inconsistency in the identiﬁed breakpoints (and hence adjustments applied) was
revealed. Of the adjustments applied for GHCN Version 4, 64% (61% for Version 3) were
identiﬁed on less than 25% of runs, while only 16% of the adjustments (21% for Version 3)
were identiﬁed consistently for more than 75% of the runs. The consistency of PHA adjustments
improved when the breakpoints corresponded to documented station history metadata events.
However, only 19% of the breakpoints (18% for Version 3) were associated with a documented
event within 1 year, and 67% (69% for Version 3) were not associated with any documented
In other words, the great majority of adjustments—and there are many and frequent adjustments
and readjustments—were made to temperature readings from weather stations that had not been
affected by any change of instrumentation, location, or environment.
The paper’s ﬁndings are further support for our choice of the independent and transparent satellite-
reading based UAH lower troposphere temperature record as the measure of global average
temperatures used for determining the progress and outcome of The Climate Bet.
February the 21st, 2022 at 11:30 pm ACST
Average start to 2022
At 0.03ºC, the UAH global temperature anomaly was only trivially different from the long run—
1991 to 2020—average of 0ºC and from the Green, Armstrong, and Soon (2009) no-trend forecast
In contrast, the 3ºC-per-century warming projection of the IPCC—standing in for Mr Gore’s failure
to quantify his 2007 “tipping point” alarm—had the anomaly at 0.460ºC in January.
Over the 169 months of the extended Climate Bet to date, the cumulative absolute error of the Gore/
U.N. IPCC manmade global warming alarm projection was 6.9 percent greater than that of the
forecast of no-trend from the 2007 average. The median, or typical, error of the warming projection
over the period was 0.16ºC too warm, while that of the no-change forecast was 0.07ºC on the cool
February the 10th, 2022 at 2:15 pm ACST
Were the last 9 years really “all among 10 hottest-ever”?
On the 13th of January, the US National Centers for Environmental Information at NOAA
announced their assessment of the global climate during 2021 under the sub-headline “2021 was the
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sixth-warmest year on record for the globe.” The announcement goes on to state that “The nine
years spanning 2013 through 2021 rank among the 10-warmest years on record.”
The NOAA assessment of the 2021 year was quickly picked up by the media, with many running an
AFP-originated article under headlines that were variations of the dramatic-sounding “Last Nine
Years All Among 10 Hottest-ever.”
Are the claims true?
The “hottest-ever” claim is unsupported by evidence.
“Ever” is a long time. The temperature record used by NOAA goes back only to the year 1880, and
does not include historically documented times of persistently warm temperatures, including the
relatively prosperous Medieval Warm Period and Roman Warm Period.
Are the qualiﬁed NOAA claims that 2021 was the sixth warmest on record and that the nine years
from 2013 to 2021 were among the ten warmest years on record nevertheless true?
The ﬁrst point to make is that the qualiﬁcation to the claims makes the claims of questionable
relevance and importance. Why should we care if recent years have been among the warmest in the
last 140 or so years? Is there any evidence that people were, on balance, worse off as a result of the
warmer years? And should we be surprised if temperatures in the latter part of the record have been
warmer than they were as the Earth emerged from the Little Ice Age in the earlier part?
The second point is that the qualiﬁed claims are only true in relation to the temperature record used
by NOAA. I’ve written in this blog before as to why we use the UAH lower troposphere
temperature anomaly series as our measure of global mean temperatures for The Climate Bet. In
short, the UAH data are derived from satellite readings and are valid measures of global and
regional temperatures estimated from publicly available sources using fully disclosed methods.
The UAH series cover the 43 years from 1979 to 2021; nearly 100 years shorter than the series used
by NOAA. Despite the relative shortness of the series, 2021 was the eight, not sixth, warmest year
according to the UAH data. And the most recent seven, not nine, years were among the 10 warmest
years in the UAH record.
Moreover, the relative warmth of the year one experienced very much depended on where one was.
There was considerable variation in how 2021 ranked for warmth using the UAH data, even when
measured across large regions.
For the northern hemisphere, 2021 was the sixth warmest—perhaps the NOAA record has a
northern hemisphere bias—whereas the southern hemisphere experienced its twelfth warmest year.
The northern polar region experienced its ninth-equal warmest year, and the southern polar region
its thirty-sixth warmest (eight coolest) year in the UAH record.
Those living in the 48 contiguous US states might be excused for thinking that 2021 seemed a little
warmer, with the average temperature for the year ranking as the third warmest in 43 years. Those
of us in Australia, on the other hand, “shivered” through the twenty-ﬁrst warmest (twenty-third
coolest) year in the UAH record!
January the 20th, 2022 at 4:30 pm ACST
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Global average anomaly for 2021 was 0.11ºC warmer than
2007 but 0.31ºC cooler than ofﬁcial warming projection
Global temperatures were cooler on average in 2021 than they were in the previous two years, and
were little different from the 0.023ºC 2007 base-year average “Bet” against Al Gore and the IPCC.
The November temperature anomaly was 0.21ºC. One month of 2021 (October) was outside the
range of monthly global average temperatures experienced during 2007.
January the 12th, 2022 at 2:15 pm ACST
November anomaly a sharp drop from October
The relative absolute error of the U.N. intergovernmental warming projection is up to 5.3% from
last month, when it was 4.3% larger than the no-trend forecast over the period of The Bet to date.
The November anomaly was, at 0.08ºC, little different from the 30-year average of 0ºC.
December the 6th, 2021 at 7:27 pm ACST
September global anomaly edged closer to IPCC warming
The latest global average lower troposphere temperature anomaly from UAH edged slightly closer
to the IPCC 3ºC-per-century warming projected from the 2007 base-year average used for the
purposes of the Climate “Bet” with Al Gore, while remaining with the 2007 range. The UAH ﬁgure
for September 2021 was 0.25ºC compared to the “dangerous” warming projection’s 0.450ºC and the
Green, Armstrong, & Soon's (2009) no-trend forecast of 0.023ºC.
What about summer temperatures?
High summer temperatures make the news, and are portrayed as a concerning symptom of
“dangerous manmade global warming” in countries such as the U.S. and Australia in particular. So
what has been the trend in August temperature anomalies in the U.S. and February temperature
anomalies in Australia? In the nearly 43 years since the UAH satellite temperature anomaly data
collection began, the OLS trend in the warmest month temperature anomalies in the U.S.
contiguous states was 0.87ºC-per-century and the ﬁgure was 0.16ºC for Australia.
October the 11th, 2021 at 05:30 pm ACST
Temperatures remain in 2007 range for a ninth month
UAH lower troposphere global temperature anomalies during 2007—the base year of the Climate
“Bet” with Al Gore— fell from +0.29ºC in January to -0.16ºC in December. The latest ﬁgure, at
0.17ºC for August, is well within that range. Recall that early in that year, Mr Gore was repeating a
claim by climate scientists that a dangerous global warming “tipping point” would occur within ten
In practice, the UAH data shows that global average temperatures in the nearly 14 years since 2007
have remained largely within the range experienced that year. As many as 113, or 69%, of the 164
months after 2007 have experienced temperatures in that range, while 20% experienced warmer
temperatures and 11% cooler temperatures.
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September the 13th, 2021 at 06:00 pm ACST
Temperatures bounce above average in July in most regions
Global temperatures continued their merry dance with a small bounce to +0.20ºC for July.
As I mentioned last month, while it is possible to ﬁt a trend line to the UAH lower troposphere
series retrospectively, estimates of the historical trend over the entire data series are closer to no-
trend—the Green, Armstrong, & Soon (2009) forecast—than they are to the “dangerous manmade
global warming” hypothesis of +3ºC per century.
Moreover, the observed trends for different regions are quite different. For example, at one extreme,
ﬁtting an ordinary least squares trend line to the the historical northern polar region temperature
anomalies ﬁnds a rate of increase of 0.0249ºC per annum whereas, at the other extreme, the rate of
increase for the southern polar region was 0.0016ºC per annum.
August 8th, 2021 at 05:30 pm ACST
Global temperature remains close to average into June 2021
The global average temperature continues to bounce around the long term average anomaly of
0.0ºC, registering -0.01ºC for June with apparent trends reversing on all time horizons. While it is
possible to ﬁt a trend line to the UAH lower troposphere series, estimates of the historical trend over
the entire data series are closer to no-trend—the Green, Armstrong, & Soon (2009) forecast—than
they are to the “dangerous manmade global warming” hypothesis of +3ºC per century.
July 8th, 2021 at 08:40 pm ACST
Global anomaly close to 2007 and 30-year averages in May
With the UAH temperature anomaly close to the 30-year average at 0.08ºC, it is interesting to look
at the different experiences of different parts of the world. For example, temperatures in the
southern hemisphere over the land were on average lower than the long-run May average (-0.11ºC),
particularly outside the tropical latitudes (-0.30ºC) and over Antarctica (-0.75ºC). In the northern
hemisphere, temperatures over the polar ocean (-0.40ºC) and the continental United States (-0.39ºC)
were also below the long-run average. Australia as a whole in May was very close to the 30-year
average at 0.02ºC.
June 9th, 2021 at 04:00 pm ACST
Global temperatures continue lower in April 2021
The UAH global mean lower troposphere global average temperature anomaly in April was
-0.05ºC, down from -0.01ºC in March. The last time two months running were below the 30-year
average to 2020 was in 2014.
Over the duration of the 160 months of “The Bet” to date, the global abnormally has been lower
than or equal to the 30-year average for 55 months, or 34% of the time, and lower than or equal to
the Green, Armstrong, and Soon no-change forecast Bet model forecasts (no change from the 2007
average) for 62 months, or 39% of months.
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May 10th, 2021 at 05:00 pm ACST
March 2021 saw temperatures back below the 2007 no-change
At -0.01ºC, the UAH global mean lower troposphere global average temperature anomaly in March
was cooler than both the 2007 Climate Bet base year and the 1991 to 2020 average anomaly used as
the base (0ºC) of the UAH series.
As a consequence, the cumulative absolute error of the IPCC/Al Gore 3ºC-per-century projection
relative to that of the Green, Armstrong, and Soon no-change forecast is again greater than 1.0, at
1.0085, after ﬁve months below 1.0. In other words, the errors of the dangerous manmade global
warming projection over the 159 months of the Bet so far are nearly 1% larger than those of the no-
change or no-trend forecast. The CumRAE has been greater than 1.0 for 153 of those months.
April 7th, 2021 at 11:10 am ACST
“Climate emergency” alarm is rejected by the data
A survey of long trends and other data by Indur Goklany—who was a member of the U.S.
delegation involved in establishing the IPCC and contributed to its First Assessment Report—found
good news on, inter alia, extreme weather events, wild ﬁres, sea levels, food production, death
rates, and life expectancy.
In short, the data do not support claims that we are experiencing a global “climate emergency.”
Rather, we have been experiencing a relatively benign climate, and have been beneﬁting from the
growth promoting effects of higher carbon dioxide levels and increasing productivity arising from
Dr Goklany’s report is available from the Global Warming Policy Foundation, here.
March 24th, 2021 at 11:10 am ACDT
New research on effect of Earth’s orbit and solar variability on
Our sometime co-author Willie Soon has recently published, with colleagues, research papers that
examine evidence on the effects on climate of cycles in the Earth’s orbit and orientation—which see
the planet sometimes closer and sometimes further away from the Sun—and variations in solar
irradiance. Both phenomena were found to have strong effects on climate, but have been ignored by
IPCC modellers who warn instead of dangerous manmade climate change.
The papers are titled “How the astronomical aspects of climate science were settled? On the
Milankovitch and Bacsák anniversaries, with lessons for today”, and “Holocene millennial-scale
solar variability and the climatic responses on Earth,” and are available on Willie Soon’s
March 17th, 2021 at 11:00 am ACDT
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New year, new base, new “site” for theclimatebet.com
Followers of theclimatebet.com will have missed the monthly updates since July of last year. They
are now back! After some technical and administrative setbacks, we have simpliﬁed the “site” to the
single pdf ﬁle that you are now looking at in order to reduce costs and the administrative burden.
Since the last post, the status of The Bet has turned to favour Mr Gore for the second time in the
course of the 157 months of the challenge so far.
The last time was for the single month 33 of the challenge: November 2010.
Having touched on the Gore/IPCC warming projection line in May 2020, the UAH lower
troposphere global temperature anomalies dropped below that line but stayed relatively high
through until November 2020 before dropping back toward the Green, Armstrong, and Soon no-
change forecast in December 2020 and January 2021. During 2019 and 2020—two months
excepted—global mean temperatures were closer to the warming projection than to no-change (no-
trend) from the 2007 average.
As a result of the relatively warm two-year spell, the cumulative absolute error of the Gore/IPCC
+3°C per century projection now stands at nearly one percent (0.77%) smaller than that of the no-
change forecast (CumRAE of Gore/IPCC is 0.9923). There have been ﬁve months in the 157
months of The Bet so far when that has been the case.
In case you are wondering, if the temperature anomaly for this month, February 2021, comes in at
even one-hundredth of a degree lower than last month’s, the Bet will swing back in favour of the
Please note that UAH’s lower troposphere temperature series (here) has now been re-based to
record anomalies relative to averages of measurements for the 30-year period from 1991 to 2020.
The Bet no-change forecasts and warming projection ﬁgures have been recalculated accordingly, so
there is no change to the ﬁndings on their relative accuracy, but the temperature anomaly ﬁgures in
degrees Celsius quoted in earlier posts will be different to the ones that are now being used.
February 12th, 2021 at 4:30 pm ACDT
June 2020 temperature anomalies remain warmer
The UAH global average temperature anomaly for June was down a few points from May, but
remained warmer than the 2007 average and closer to the warming than the no-change line. That’s
13 months in a row in Mr Gore’s favor!
July 4th, 2020 at 6:01 pm
May temperatures jag up as warmer spell continues for 12
The UAH global average temperature anomaly (lower troposphere) for May 2020 was again closer
to the IPCC-Gore “dangerous” warming projection from the 2007 average than to the Green-
Armstrong-Soon forecast of no-change (trend). The absolute error from predicting dangerous
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warming remains greater than that of the error from no change over the more than 12-years of the
Climate Bet so far, however, being 2.6% greater.
The May ﬁgure was yet another reversal in the direction of change (“trend”) from one month to the
next. That is the norm. Over the now more than 40 years of the UAH temperature series, the
correlation between the monthly change in temperature anomaly and the change in the previous
month was negative (-0.33). To put it another way, for more than 55% of months, the direction of
change from the previous month was the opposite of direction of change a month before.
June 9th, 2020 at 7:27 pm
April 2020 warmish, but coolest since July last year
April’s anomaly remained above halfway between the no-change—from 2007 annual average—
forecast and the IPCC/Gore +3°C per century warming projection, and so with its smaller error
counts as a win for the month for the projection.
The recent run of warmer global average temperatures has pushed the cumulative relative absolute
error to 1.039—which means that the warming projection’s cumulative absolute error is 3.9% larger
than that of the no-change forecast—the lowest it has been since December 2010, 3 years into The
As a consequence of the run of warmer temperatures, The Bet is more alive now than it has been for
about a decade. For example, if the UAH global mean temperature anomaly turns out to be close to
the red IPCC/Gore warming line for each of the next three months, the cumulative error from that
projection would be smaller that that of the no-change forecast.
May 8th, 2020 at 2:43 pm
March 2020 cooler than IPCC/Gore projection for ﬁrst time
As expected from the history of the series, the UAH global average lower troposphere temperature
anomaly declined in March. The decline took the temperature to a level last seen in October.
Why expected? Considering the whole UAH series (496 months less 2), the correlation between the
month-to-month change in temperature and the previous month-to-month change (the lagged series)
is -0.3322. The negative sign indicating that if the most recent month’s temperature anomaly is up
on the previous one, the next month is more likely to be down, and vice versa.
How likely is a reversal of direction between months? The probability is about 0.55, based on the
494 available observations to date.
Finally, the temperature anomaly increased in slightly less than half of 495 months or 49.5%.
April 21st, 2020 at 11:15 am
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Global temp warmer than 3°C/century trend for 4th month
Global mean! temperatures have been warmer than the IPCC/Gore 3°C per century extrapolation for
the four months to February 2020. All but one month (May 2019) in the last 14 months has been
closer to the IPCC extrapolation than to the Green, Armstrong and Soon (2009) no-trend forecast.
Does that mean that the global warming extrapolation is now ahead in the extended, 20-year,
No, it does not. The cumulative monthly error from betting on a!3°C-per-century extrapolation from
the 2007 annual average temperature anomaly is more than 5% greater than the error from betting
on no change.
The relative error of the warming extrapolation is the lowest it has been for 109 months, but it has
only been less than 1.0—warming more accurate than no-change—for two months of the 146
months of the extended Bet so far, back in 2010.
March 12th, 2020 at 3:27 pm
Temperatures remained warmer than average in January 2020
The UAH global average temperature anomaly was 0.56°C in January, which was the same as it
was in December of last year and not much different from the 0.55°C in November. In the 145
months of the Climate Bet so far, the global temperature anomaly has been 0.56°C or warmer for
only nine months, albeit all of those months occurred after 2015.
An inspection of the Whole-Earth Thermometer with the updated data, reveals that temperatures go
down just about as often as they go up. The ﬁgures for the life of The Bet so far are 47% down, and
For the entire UAH temperature anomaly series of 494 months to date, the anomaly was higher than
it was in the previous month 50% of the time, and the direction of change in the anomaly reversed
for 55% of months. The correlation between the direction of change in the month with the direction
of change in the previous month was negative 0.33.
February 11th, 2020 at 4:45 pm
Claims 2019 warmest Australian year inconsistent with
The UAH global average! temperature anomaly relative to the 1981 to 2010 average was 0.56°C in
December, up from 0.55°C the previous month. The 2019 average was the second warmest year in
the 12 years of The Bet so far, as is shown by the blue stepped line in the “Whole-Earth
Thermometer” chart on the top-right of this page.
While the global anomaly for 2019 was closer to the IPCC-Gore 3°C-per-century warming
extrapolation line than to the Green-Armstrong-Soon no-trend forecast, it was below the warming
line, as it has remained for all but two of the Bet’s 12 years to date.
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The Climate Bet is concerned with the global average temperature anomaly, but local and regional
anomalies do not follow in lock step, and sometimes differ markedly. The claim by Australia’s
Bureau of Meteorology (BOM) that “2019 was … the warmest … year on record for Australia …
since consistent national temperature records began in 1910” is therefore not inconsistent with what
was a relatively unremarkable year in the global record.
But how does the BOM’s warmest-on-record claim—based on smattering of “homogenized” land-
based readings—stack up against the UAH satellite (lower troposphere) data for Australia?
Not very well, it turns out.
According the UAH data, 2019 was only the fourth warmest year in Australia in the 41 years of the
UAH satellite temperature anomaly record. The warmest year in the UAH data was 2017, with an
average anomaly of 0.71°C. The ﬁgure for 2019 was 0.58°C. The years 2016 and 1998 were also
warmer for Australia.
Roy Spencer—one of the researchers behind the UAH data—has provided an analysis of the
relationship between claims of anthropogenic global warming and measured temperature,
precipitation, and Australian bush ﬁres.
January 9th, 2020 at 11:46 am
November 2019 sees global temperature above Bet warming
With the release of the UAH November 2019 global temperature anomaly, there have been 28
months in which the anomaly equaled or exceeded the 3°C-per-century warming trend line
projected from the 2007 Bet base year average. That compares with the 57 months in which the
anomaly has been less than or equal to the scientiﬁc no-change forecast proposed by Green,
Armstrong, and Soon (2009) and the basis of Scott Armstrong’s challenge to Al Gore to bet on
forecasts of global temperatures.
Those ﬁgures give a sense of how modest the IPCC’s 3°C-per-century warming trend is compared
to month-to-month variations over the 143 months (nearly 12 years) of the extended Bet so far. The
28 months of temperature anomalies greater than or equal to the warming trend account for nearly
20% of months, while close to 40% of months have been cooler than the 2007 base year average.
December 13th, 2019 at 9:27 am
September 2019 anomaly above IPCC/Gore warming for ﬁrst
time in 2 years
September recorded the warmest global mean temperature anomaly since October of 2017. If the
months of the fourth quarter of 2019 stay on the warmer side, 2019 could be the fourth year in
twelve in which the annual average global temperature anomaly has been closer to a 3°C-per-
century warming trend than to no-change.
October 12th, 2019 at 10:52 am
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No change in global average temperatures from July to August
The UAH global average lower troposphere temperature anomaly remained unchanged in August
2019 from the previous month at 0.38°C. The month!counts as the seventh win for Mr Gore out of
the eight months of this year so far—the 44th win out of the 140 months of the extended bet, so far.
With no change in the average, it is interesting to observe to what extent!the regional averages
changed. Average temperature anomalies in the tropics fell!from 0.61°C to 0.37°C over the land and
rose from 0.40°C to 0.44°C over the sea. The corresponding ﬁgures for the northern polar
region!were a rise from 0.25°C to 0.53°C and a fall from 0.42°C to 0.33°C, and for the southern
polar region were a fall from 0.86°C to 0.51°C, and a rise from 0.05°C to 0.38°C.
September 19th, 2019 at 9:21 pm
Warmer temperatures persist over 2019 to July
UAH’s measure of global average temperatures has not above the Al Gore/IPCC warming
projection since February 2017, but the monthly mean temperatures this year have nevertheless
remained closer to that projection than to the no-trend forecast in all but one of the seven months.
For the 139 months of the Climate Bet so far, the monthly average temperature has been warmer
than the warming projection for fewer than 19 percent of months, and has been below the no-trend
forecast for 41 percent of months.
August 17th, 2019 at 4:19 pm
June 2019 warmer than May, on average
At 0.47°C, June’s global temperature anomaly was up from May’s, and was the warmest since
October 2017, 20 months ago. The June ﬁgure was also slightly warmer than the 2007 Bet base
year’s maximum monthly anomaly of 0.43°C.
The experience of regions varied considerably, however, as US readers will likely have noticed. The
anomaly for the 48 contiguous U.S. states was -0.64°C, which was even cooler than May, the
previous month. Australia’s anomaly, while positive, was cooler than the previous 3 months, as was
the case with the entire southern hemisphere over the land.
The northern polar region experienced a positive anomaly (0.90°C), but that was cooler than those
of!the 4 previous months, while the southern polar region experienced a negative anomaly (-0.39°C)
that was cooler than the anomalies of the 8 previous months.
July 5th, 2019 at 11:26 am
“Do we face dangerous global warming?”
Was the title of a talk that Scott Armstrong gave to his fellow Lehigh University Graduating Class
of 1959 at their 60th Reunion on June 7. The invited talk addressed the question of whether the
alarm over dangerous manmade global warming is a valid scientiﬁc claim, and presents ﬁndings
from!Scott’s research with Kesten Green. A copy of the slides for the talk is available from
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June 11th, 2019 at 1:44 pm
April 2019 warmer, again
The global mean UAH lower troposphere temperature anomaly ticked up again in April. So far,
2019 global monthly averages have all been warmer than the warmest month in 2018.
May 13th, 2019 at 11:30 am
March quarter 2019 temperatures warmer than 2018
The UAH lower troposphere temperature global average anomalies for the ﬁrst three months of
2019 have been higher than at any stage during 2018 to the extent that they were slightly closer to
the 3°C-per-century warming projection from the IPCC than they were to the no-change (no-trend)
forecast. By contrast, every month of 2018 was closer to the no-trend forecast. Over the 135 month
term to-date of the extended Climate Bet, the global average temperature has been closer to the no-
change forecast than to the IPCC “dangerous warming” forecast!for more than 70% of months.
April 12th, 2019 at 11:51 am
February 2019 sees little change
The February 2019 global temperature anomaly ﬁgure (lower troposphere) from UAH has been
added to the Climate Bet chart—aka Whole-Earth Thermometer.
March 21st, 2019 at 8:42 am
A warmer start to 2019 sees January a winning month for Mr
At 0.37°C, the January 2019 anomaly was the highest since since December 2017. Just above the
mid-point between the no-change from the 2007 average forecast of 0.159°C and the IPCC/Gore
3°C-per-century “dangerous” warming forecast for January of 0.505°C, the month counts as a win
for Mr Gore.
So far, the monthly wins tally stands at:
dangerous warming trend: 40 months
no trend (Armstrong): ! ! ! ! 93 months.
Over the course of the Bet to date, the dangerous warming forecast has never been the better
forecast for as many as 40% of months. The no-trend, no need for policy action, forecast remains
the best bet, having won just under 70% of months so far.
February 12th, 2019 at 2:10 am
2018 year ends on a low note, temperature wise
The UAH global mean temperature anomaly data for December 2018 is out: the!ﬁgure of 0.25°C.
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The average for the year was 0.23°C, with a maximum anomaly of 0.32°C and a minimum of
0.15°C. None of those ﬁgure is!much different from the 2007 Bet base year average of 0.16°C, and
are all well within the base year range of -0.04°C to +0.43°C.
Interestingly, in the now 11 years since 2007, monthly global mean temperature anomalies have
fallen outside the 2007 range on only 32 of the 132 months, with nearly half of those months (15)
falling below the 2007 minimum.
The 2018 year was cooler than any of the previous three years, and cooler also than 2010. In other
words, 2018 was cooler than 40% of the previous ten years.
So how do things stand with the extended “Bet” between the no-change model forecasts and the
IPCC’s 3°C-per-century “dangerous” warming projection!(standing in for Mr Gore’s “tipping point”
After 11 years, the Bet’s summary measure—the cumulative absolute error of the warming
projection relative to that of the no-change forecasts—is 1.211. In other words, the errors of the
“dangerous” warming projection have been 21.1% larger then the errors of the forecasts from
a!simple model that assumes that we do not know enough about the!causes of climate change to
make predictions over policy-relevant horizons that are more accurate than an extrapolation of!the
previous year’s average into the distant future.
Note also that unbiased forecasts would be expected be warmer than the actual temperature as often
as they were cooler. To date, the actual temperature has been equal to or warmer than the IPCC/
Gore projection for only 18.2% of months. That ﬁgure compares with the 40.9% of months that the
temperature anomaly has been less than or equal to no-change projection.
January 7th, 2019 at 2:10 pm
“…new report from the Nongovernmental International Panel
on Climate Change show humans are not causing a climate
A new 1,000-page report titled Climate Change Reconsidered II: Fossil Fuels by the
Nongovernmental International Panel on Climate Change!was presented on December 4 in
Katowice, Poland. (In case you missed it, Katowice is where the many delegates to the UN
Framework Convention on Climate Change gathered from far and wide to argue for climate alarm.)
Climate Change Reconsidered II: Fossil Fuels assesses the costs and beneﬁts of the use of fossil
fuels (principally coal, oil, and natural gas) by reviewing scientiﬁc and economic literature on
organic chemistry, climate science, public health, economic history, human security, and theoretical
studies based on integrated assessment models (IAMs). It is the ﬁfth volume in the Climate Change
Reconsidered series and, like the preceding volumes, it focuses on research overlooked or ignored
by the United Nations’ Intergovernmental Panel on Climate Change (IPCC).
The chapters of the report are:
Part 1: Foundations
1. Environmental Economics
2. Climate Science
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Part II: Beneﬁts of Fossil Fuels
3. Human Prosperity
4. Human Health Beneﬁts
5. Environmental Beneﬁts
Part III: Costs of Fossil Fuels
6. Air Quality
7. Human Security
8. Cost-Beneﬁt Analysis
A press release, Summary for Policymakers, the report itself as one large ﬁle, and individual
chapters are available to download from the NIPCC site, here.
December 7th, 2018 at 2:15 pm
November 2018 temperature data, and the UAH trend
The November lower troposphere global temperature anomaly from the University of Alabama at
Huntsville (UAH) team is just out, is little different from recent months, and remains close to the
2007 average that is the base-year of The Climate Bet.
The UAH series now covers nearly 40 years of monthly observations. Over that time, the change in
the global average temperature from month to month has been quite small: the absolute change has
averaged a little less than 0.1°C, with half warmer than the previous month, and half cooler.
Despite the obvious up-and-down nature of the series, some commentators continue to look for
evidence of a trend hiding in the noise of monthly and annual volatility. For example the IPCC’s,
business as usual 3°C-per-Century should be evident in 40 years of data if it amounted to a real
Followers of the IPCC would presumably be pleasantly surprised, then, to learn that the trend to
date amounts to little more than 0.001°C-per-month; less than 1.3°C-per-Century. In other words,
from month-to-month the typical up or down change!is in the order of a 100 times larger than the
If the well-hidden trend happened to continue for a further!60 years, we should be reassured that it
is much closer to the no-change forecast than to the dangerous warming scenario. There continues
to be!neither!reason!to worry, nor reason for governments to implement expensive programmes and
December 5th, 2018 at 2:35 pm
October 2018 temperatures in the middle of the 2007 base year
The 2007 base year of The Bet saw UAH global temperature anomalies range from 0.43°C to
-0.13°C. The latest ﬁgure—of 0.22°C for October 2018—lies more-or-less in the middle of that
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Of the 130 months of the extended Bet, so far, 32 months—less than!one-quarter—have fallen
outside the base-year range. Of those months with temperatures falling outside that range, nearly
one-half (47%) were cooler than the coolest month of 2017.
November 9th, 2018 at 10:32 am
“DataGate” – The ofﬁcial temperature series from Hadley
From time to time we explain on this site why we use the fully disclosed and audited University of
Alabama satellite reading derived lower troposphere temperature series for adjudicating the
progress of The Climate Bet. And now the temperature data that are relied upon by the IPCC and
policy makers around the world have been audited.
“Thanks to Dr John McLean, we see how The IPCC demands for cash rest on freak data,
empty ﬁelds, Fahrenheit temps recorded as Celsius, mistakes in longitude and latitude,
brutal adjustments and even spelling errors…
There are cases of tropical islands recording a monthly average of zero degrees — this is the
mean of the daily highs and lows for the month. A spot in Romania spent one whole month
averaging minus 45 degrees. One site in Colombia recorded three months of over 80 degrees
For more on Dr McLean’s report documenting the unreliability of the Hadley Centre’s data, see Jo
Nova’s blog entry, here.
October 11th, 2018 at 10:47 am
September 2018 temperatures drift lower
The UAH temperature anomaly for September was for the ﬁrst time since July 2015 lower than the
2007 base year average that is the basis for the Climate Bet. With that latest dip in the global mean
temperature, 42% of the 129 months of the extended bet period have seen temperatures lower than
the base year average, which is also the no-change forecast proposed for the “Bet” by Professor
To put the 42%!ﬁgure into context, consider that over a long period of time one would expect the
actual temperature to be lower than an unbiased forecast about half of the time, and above it half of
the time. While 42% is not 50%, contrast the ﬁgure!with the percentage of months for which the
actual temperature was greater than the Gore/IPCC global warming extrapolation of 0.3°C per
decade… that ﬁgure is less than 19%.
With 111 months of the second decade of the bet remaining, the actual temperature would need to
be below the 2007 average for 59.4% of months for the no-change forecasts to be counted as
“perfectly” unbiased. For the dangerous warming forecast to be considered “perfectly” unbiased,
actual temperatures would need to fall above the 0.3°C per decade trend line for 86.4% of months.
October 6th, 2018 at 3:04 pm
August 2018 global average temperatures unremarkable
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The latest lower troposphere—the part of the Earth’s atmosphere where weather occurs and life
exists—monthly average temperature anomaly from UAH is shown in the revised chart to the top
right of this page. Click the thumbnail image for a larger image and table of recent data.
The August ﬁgure was 0.19°C, little different from the 2007 Bet base year average of 0.16°C.
September 17th, 2018 at 10:34 am
July temperature update sees more of the same
The UAH global average temperature anomaly was closer to the 2007 Bet base-year average that
the IPCC-Gore warming projection again!in July 2018. That has been the case !for every month of
this year, so far. Note also that for more than 75% of the 127 months of the bet so far, the
temperature anomaly has not been outside of the range of the 2007 monthly averages.
August 9th, 2018 at 3:01 pm
June 2018 temperature falls near middle of 2007 base year
The UAH mean global temperature anomaly estimate for June 2018 was 0.21ºC. For the year-to-
date, the average is cooler than!the average for last three years, and close to the 2007 Bet base year
average. The monthly anomalies in 2007 ranged between -0.04 and 0.43°C.
An inspection of the updated chart (top right) of this page shows that the recorded temperature has
only!infrequently exceeded the !IPCC/Gore projection of 3ºC per century of warming. In fact the
recorded temperature has been lower than the dangerous warming projection for 82% of months
since the end of 2007. That ﬁgure compares unfavourably with the 57% of months for which the
actual temperature was warmer than Armstrong’s bet on the no-change forecast. Note that a ﬁgure
of 50% would be unbiased.
July 10th, 2018 at 7:07 pm
Science, and forecasting climate
Scott Armstrong presented a paper at the International Symposium on Forecasting in Boulder, CO,
on 19 June titled “Do Forecasters of Dangerous Manmade Global Warming Follow the Science?”. A
pdf copy of the slides is available from ResearchGate, here.
July 5th, 2018 at 12:50 pm
May 2018 temperature close to 2007 average
After two years or so of warmer temperatures, 2018 global average temperatures have so far been
close to the 2007 average. That ﬁgure—an “anomaly” of 0.159°C—is the baseline for the Scott
Armstrong’s!“Bet” with Al Gore, and hence the value of the no-change forecast that Professor
Armstrong is backing against Mr Gore and the IPCC’s dangerous global warming projection.
June 7th, 2018 at 6:24 pm
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Are we living on a dangerously warming planet?
The news keeps coming in from the New York Times and other media that there is no longer any
doubt that the Earth is getting dangerous warmer. If you believe that to be!true, there is nothing that
we can say to change your opinion. Only you can do that. And to do so, you ﬁrst need to address
this question: “Could I imagine anything that could possibly change my mind?”
If so, you might be interested in the short article on WUWT titled “Is the Earth becoming
dangerously warmer?“. It might provide the information you are seeking.
June 4th, 2018 at 2:25 pm
April 2018 temperatures show little change
Our update of the Whole-Earth Thermometer chart (to the upper right of this page) with the UAH
April 2018 global mean temperatures shows temperatures were remarkably close to the 2007
Climate Bet base year average of 0.16°C.
The chart as a whole could reasonably be characterised as showing temperatures drifting sideways,
largely within a +/-0.3°C band. Not surprisingly, then, the cumulative absolute error of the Gore/
IPCC dangerous warming projection has been smaller than that of the no-trend forecast for only
2!of the 124 months of the bet so far, and that was back in September and October 2010.
May 7th, 2018 at 10:53 am
March 2018 cooler than same month of 2007 Bet base year
Temperatures have drifted up and down since Mr Gore warned of a dangerous warming “tipping
point” at the start of 2007, as they always have. Eleven years on, the temperatures recorded for the
ﬁrst 3 months of this year look remarkably similar to the ﬁrst 3 months of 2007: 0.26°C, 0.20°C,
and 0.24°C compared to 0.43°C, 0.19°C, and 0.26°C.
April 14th, 2018 at 7:20 pm
February 2018 temperatures same as 11 years ago
The UAH global temperature anomaly for February 2018 was 0.20°C, which is little different from
the February 2007 ﬁgure of!0.19°C, and lower than January and March 2007 ﬁgure of 0.43°C and
0.26°C. The updated chart for the extended (20 year) Climate Bet is at right. Click on the thumbnail
chart for a larger image.
Some critics of our recent analysis of the Climate Bet at 10 years argued that!temperatures were
clearly higher at the end of the Bet period than they were at the beginning. Professor!Armstrong’s
side of the bet was the Green, Armstrong, and Soon (2009) no-change!(no-trend) forecast. If the no-
trend model of global mean temperatures is correct, there is a 50/50 chance that the temperature at
the end of any!period will be higher than at the beginning… and so comparing ending and starting
observations is of no value in determining whether there is a dangerous trend, or not.
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The Climate Bet instead compares cumulative absolute errors, which is the appropriate measure for
assessing whether policy should be based on dangerous warming, or no change. To date, the
cumulative absolute error of the dangerous warming forecasts of!3°C per century is nearly 15%
larger than that of the no-change model forecasts
Other critics suggested that there was an upward trend over the bet period. !Trend lines can be ﬁtted
to random data… and, ex post, to series that cannot be forecast better than no-change. And people
seek!patterns. Given that preference, we will occasionally report on how the trend of the dangerous
warming !projection and no trend compare with the!ex post trend ﬁtted to the global temperature
For the period of the Climate Bet to date, the ordinary least squares trend from the 2007 annual
average Bet base year was 1.49°C per century; closer to no trend than to!the dangerous warming
forecasts of!3°C per century. But, as we discussed in our 10-year summary, squared errors are not
relevant for policy decisions. The more policy-relevant least absolute deviation trend for the period,
by contrast, was a much ﬂatter!and non-dangerous 1.17°C per century.
March 12th, 2018 at 3:44 pm
Climate Bet starts a second 10 years with cooler month:
With Professor Armstrong keen to put his!evidence-based no-change forecast to the test for a
further!ten years, we have updated the Climate Bet chart with the!121st bet month of!UAH lower
troposphere data. January 2018’s global temperature anomaly was 0.10°C higher than the forecast
of no trend in temperatures from the 2007 average, and 0.22°C lower than the “dangerous manmade
global warming” Gore/IPCC +3°C per century extrapolation.
February 28th, 2018 at 9:55 am
Tipping point 10 years on: Who won the Armstrong-Gore
“bet” on the climate?
In 2007, University of Pennsylvania Professor J. Scott Armstrong challenged former U.S. Vice
President Albert Gore to a bet on what would happen to global average temperatures over the next
10 years. Professor Armstrong’s challenge was in response to Mr. Gore’s warning of a looming
dangerous “tipping point” in temperatures. But when even scientists who are expert in a ﬁeld make
predictions about complex situation without using scientiﬁc forecasting methods, their forecasts
have no value. The proposed $10,000 bet, then, was intended to draw attention to the need to assess
the predictive validity of climate forecasts in an objective manner.
Emails to Mr. Gore were unproductive: after several attempts at engagement, his staff informed
Professor Armstrong that Mr. Gore did not take bets. The important question of whether public
policies should be based on the alarming projections had not gone away, however, and so
Armstrong commissioned theclimatebet.com site to track how the bet would have turned out had
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At the time of the challenge, Mr. Gore had been warning that climate was warming at such a rate
that large public expenditures were needed in great haste in order to prevent disaster. His book
Assault on Reason—published in April 2007—stated on p. 204: “Many scientists are now warning
that we are moving closer to several ‘tipping points’ that could –!within as little as ten years!– make
it impossible for us to avoid irretrievable damage of the planet’s habitability for human
Formulating The Climate Bet
Mr. Gore did not quantify his dangerous warming forecast, and so the “business as usual” projection
provided by the U.N. Intergovernmental Panel on Climate Change’s Third Assessment Report in
2001 was used to represent his forecast. Using the IPCC projection of!3°C per-century warming
favored Mr. Gore’s side of the bet because it was considerably less dramatic than the “tipping point”
claims he was articulating and some of the IPCC’s own more extreme projections.
Professor Armstrong’s side of the bet was that the global average temperature would not change.
The no-change forecast is consistent with a statement in the body of the aforementioned IPCC
technical report. The report stated, “In climate research and modeling, we should recognize that we
are dealing with a coupled non-linear chaotic system, and therefore that the long-term prediction of
future climate states is not possible.” In other words, forecasting long-term trends in climate is
impossible and, by implication, forecasting long-term changes in global mean temperatures is
The IPCC statement is also consistent with Green, Armstrong and Soon’s (2009) conclusion that the
forecast of no-change in global temperatures over the long term would be hard to beat in terms of
accuracy, even when applied to the U.K. Met Ofﬁce Hadley Centre’s questionable annual average
temperature data—based on adjusted thermometer readings from selected sites from 1850—that is
used by the IPCC. Green, Armstrong and Soon found that no-change forecasts were so accurate for
practical purposes—e.g., average errors of only +/- 0.24°C for 50-year-ahead forecasts—that there
would be no point in trying to do better.
The IPCC 3°C-per-century projection not only ignored their own authors’ conclusion about the
inability to predict long-term trends, their procedures violated 72 of 89 relevant forecasting
principles (Green and Armstrong 2007). As a consequence, there is no reason to expect the IPCC
dangerous warming projection to be accurate over the long term, and thus no good reason for using
it as the basis for policy.
Global temperatures have always varied on all time scales, however, so it was quite possible that
Armstrong would lose a ten-year bet when temperatures have commonly drifted up or down by
0.3°C over ten-year periods in the past. A 150-year simulation of the bet suggested that his chance
of winning was only about 70%.
Determining the Winner
In the end, the bet was offered, and monitored, on the basis of satellite temperature data from the
University of Alabama at Huntsville (UAH). In contrast to surface data, the lower troposphere
satellite data covers the whole Earth, is fully disclosed, and is not contaminated by poor
maintenance and location of weather stations, changes from mercury to electronic measurement,
and unexplained adjustments.
The cumulative absolute error (measure 1 in the table) was the key criterion for assessing accuracy.
That measure has been tested and shown to be the best way to compare the accuracy of forecasts
Page of 28 152
from different forecasting methods (Armstrong and Collopy 1992). By that measure, the no-change
forecast reduced forecast errors by 12% compared to the IPCC dangerous warming projection.
Forecasting models that cannot provide forecasts that are more accurate than the no-change forecast
have no practical value.
The ﬁnding is consistent with Green and Armstrong’s 2014 analyses that compared the predictive
validity of the no-change and IPCC forecasts over different time periods. The Loehle AD16 to 1935
temperature series was used to compare the accuracy of the global warming, global cooling, and no
change forecasts over horizons from one to 100 years ahead; the no-change hypothesis was much
more accurate than the global cooling hypothesis of 1°C-per-century cooling, which, in turn, was
much more accurate than the global warming hypothesis of 3°C-per-century warming.
Alternative Measures of Winning
There are other ways that one might assess accuracy, especially since the bet was tracked each
month, but the outcome is clear: there was no dangerous “tipping point” over the ten-year period.
Global temperatures fell well within the range of natural variation. Seven alternative measures are
presented in the table below so that readers can make their own assessments.
See the Golden Rule of Forecasting,!here.
The second and third measures in the table provide measures of bias in the forecasts. By both
measures, the no-change forecast is substantially (18% and 79%) less biased.
Another way to look at bias is shown in the chart: the blue shading indicates the difference between
the Armstrong/no-change forecast and the actual temperature when the forecast was too warm, and
the red shading indicates the difference between the Gore/IPCC projection and the actual
temperature when the projection was too cold. A perfectly unbiased forecast would have 50% over-
and 50% under-forecast errors. The sum of the Armstrong/no-change over-forecast-errors was 41%
of the corresponding total absolute error, whereas the sum of the Gore/IPCC under-forecast-errors
was only 14%. In other words, the Armstrong/no-change model produced forecasts that were close
to unbiassed over the 10 year period, whereas the Gore/IPCC model projection was grossly biassed
Page of 29 152
to forecast too warm, to the extent that the Gore/IPCC error from forecasting too warm was six
times larger than the error from forecasting too cool.
How would planners who had relied on the ofﬁcial IPCC projection have fared? Looking again at
the chart, planners would have expected “extra” warmth represented by the area of the triangle
between the red IPCC line and the green no-change line (19.8). The extra warmth actually
experienced over the period is represented by the area between the black actual temperature line and
the green line: the area above the green no-change line, less the area below the no-change line
(3.47). In other words, planners relying on the IPCC projection would have experienced less than
18% of the extra warmth that they had planned for.
Those who insist on looking for a trend in the decade of seesawing temperatures will ﬁnd no
support for either a “tipping point,” or the IPCC’s dangerous warming trend projection, in the best-
ﬁt line, which runs at a rate of little more than 1°C per-century[i]. As the footnote to the table
explains, the ﬁtted ordinary least squares (OLS) trend from the 2007 annual average base was
1.53°C per-century, and the least absolute deviation ﬁtted (LAD) trend was 1.17°C per-century.
When the bet forecasts are assessed against the OLS trend, the Gore/IPCC 3°C per-century
projection is slightly closer (measure 5 in the table), but the Armstrong/no-change forecast is 44%
closer to the more relevant LAD trend (measure 6). (Why would decision makers want to minimize
squared errors?) Moreover, the trend line for the period of the bet was closer to no-change than was
the trend over the entire UAH temperature anomaly series to the end of 2017.
The arbitrariness of ﬁtting a trend—by whatever method—to such a series is reinforced by the fact
that if the bet had been for ﬁve years, rather than 10, the ﬁtted trend would have been negative:
-1.13°C per century (LAD), or -1.61°C per century (OLS). Note also that on 10 February 2007, Sir
Richard Branson was accompanied by Mr. Gore when he stated that the “world may already have
crossed a ‘tipping point’”, and so one might ask whether the temperature at the end of the bet was
dramatically higher that it was then, when the January 2007 UAH ﬁgure of 0.43°C had just been
released. The answer is no: the December 2017 ﬁgure was lower at 0.41°C.
Page of 30 152
The Future of The Climate Bet
Longer is better for assessing climate forecasts, and so theclimatebet.com site will monitor the “bet”
in line with Scott Armstrong’s offer to extend the challenge for another ten years by sticking with
the original 2007 annual average global temperature as the starting point. Extending the bet is
intended to help further publicize the important role of scientiﬁc validation of forecasts that
inﬂuence public policy. Policymakers should reject forecasts that fail to reduce errors compared to
an appropriate no-change benchmark.
Kesten C. Green
26 January, 2018
5 February, 2018 (extended analysis)!
[i] Technical note to facilitate replication: The Climate Bet was framed in terms of what would
happen to temperatures relative to the 2007 average, the year in which Mr. Gore warned of a
“tipping point” and Professor Armstrong tried to get him to engage in a bet. Logically, then, if one
insists on ﬁtting a line through such a volatile time series, the starting point should represent the
situation at the time the claim (tipping point) and challenge (offer of bet were made). The Gore
tipping point claim was made in early 2007, so one could make a case for ﬁtting trend lines with an
origin at .43C (January 2007) but, given that discussions proceeded over the 2007 year and that
monthly temperatures are so volatile, the 2007 average was chosen as the base for the bet; hence,
also, as the value of Professor Armstrong’s no-change forecast, and the origin for trend line ﬁtting.
Given that the data are monthly and the origin was an annual average, lines are ﬁtted with the origin
located in mid-2007. A close look at the chart reveals that the red IPCC/Gore +3°C per century line
is also projected on that basis: it is slightly above the green no-trend/2007-average line at the
beginning of 2008.
Page of 31 152
January 27th, 2018 at 7:38 am
November 2017 sees warmth ease
At!0.36°C, the UAH November global average lower-troposphere temperature anomaly was lower
than the 2016 average and roughly equal to the 2017 average to-date. Despite being down,
the!November ﬁgure is closer to the Gore-IPCC projection than to the Armstrong-no-change
forecast—that has been the case for 31% of the 119 months of the bet to-date.
With only one month of the 10-year bet remaining, we will hold off on more detailed analysis until
the new year.
December 12th, 2017 at 2:36 pm
October 2017 sees three warmer months in a row
With a monthly anomaly of 0.63°C (UAH Lower Troposphere), October was the third month in a
row with temperatures closer to the IPCC/Gore dangerous manmade warming scenario than to
Professor!Armstrong’s no-trend forecast from Green, Armstrong, and Soon (2009).
With two months of the 120 month (2-year) Climate Bet to go, however, the absolute error of Mr
Gore’s projection remains more than 15% larger than Professor Armstrong’s.
November 8th, 2017 at 11:24 am
September 2017 warmer
The September global average temperature anomaly was, at +0.54°C, the 5th warmest month of the
117 months of the 10-year bet so far.
The Gore/IPCC projection has provided a more accurate prediction of the temperature than
Professor Armstrong’s no-change forecast!for 19 of the last 24 months. Overall, however, the no-
change forecast has been more accurate for 70% of the months of the bet so far.
October 6th, 2017 at 2:25 pm
August 2017 warmth keeps the Climate Bet interesting
After two cooler months that were closer to Professor Armstrong’s bet on the Green, Armstrong,
and Soon (2009) no-trend forecast than to the Gore-IPCC manmade global warming projection, the
UAH’s August global average temperature “anomaly” was, at +0.41°C, close to the warming
projection’s 0.46°C for the month.
The August ﬁgure means that temperatures have been closer to the Gore-IPCC projection for four of
the eight months of 2017 so far, and the absolute error for that period has been nearly 14 percent
smaller than the no-trend forecast error.
With only four months of the ten-year bet remaining, we look forward to presenting detailed
analysis of the full period of The Bet in the New Year.
Page of 32 152
September 19th, 2017 at 11:14 am
July 2017: Another unremarkable month for the global
The !global mean temperature anomaly for the month of July 2017, as estimated by the UAH
!climate!scientists, was 0.29°C. If it weren’t for the cries of alarm about what Mr Gore and others
speculate might happen, there would be little interest in this obscure and unremarkable
Mr Gore and the IPCC did raise!the alarm, however, so here on theclimatebet.com site we will
continue to monitor the performance of Mr Gore and the IPCC’s 3°C per century of warming
projection relative to Professor Armstrong’s bet on scientiﬁc forecasting forecasting and the Green,
Armstrong, and Soon (2009) no-change model. With only 5 months of the ten-year notional bet left
to run, the cumulative absolute error of the Gore/IPCC projection is 21% larger than the error of the
August 14th, 2017 at 11:36 am
On “Alarming Climate: Expert opinions and government
funding versus scientiﬁc forecasting”
Kesten Green, Scott Armstrong, and Willie Soon responded to MIT President Reif’s apparently
unshaken belief in dangerous manmade global warming in a letter published by WUWT on July 20.
The letter starts as follows:
On June 17, we and our co-authors received a response to our letter to MIT President, Professor
Reif, raising concerns about his letter to the MIT community in support of the Paris Climate
Accord. Professor Reif’s response stated that he was conﬁdent in his position on the issue because it
is consistent with the beliefs of experts that implementation of the Paris Accord is necessary to save
the world from harmful effects of man-made global warming. We are not reassured.
The read the full letter, published on WUWT under the headline “Alarums And Excursions”, here.
July 21st, 2017 at 10:33 am
Mr Gore’s alarming warming projection too hot for June 2017
After period of warmer global average temperatures, June 2017 experienced!a mean anomaly of
0.21°C. The ﬁgure was 0.05°C higher than Professor Armstrong’s forecast, and 0.25°C lower than
Mr Gore’s IPCC warming projection. Despite the fall in average temperature and a clear win for the
month for Professor Armstrong, 59% of previous months over!the course of the bet were cooler.
As always, there were!regional variations. For example, the average temperature anomaly over land
in the southern hemisphere was (slightly) negative.
July 13th, 2017 at 10:55 am
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Letter to MIT President Reif in effort to dispel dangerous
In a letter dated June 2 sent to the MIT Community entitled, “Letter regarding US withdrawal from
Paris climate agreement,” MIT President, Professor L. Rafael Reif criticized the decision taken by
President Donald Trump to exit the Paris Agreement. In the following rebuttal of Professor Reif’s
letter, we seek to clarify the state of scientiﬁc understanding of climate. We do so in order to dispel
the popular delusions that we are faced with a problem of dangerous manmade global warming, and
that the Paris Agreement would be beneﬁcial.
Istvan Marko, J. Scott Armstrong, William M. Briggs, Kesten Green, Hermann Harde, David R.
Legates, Christopher Monckton of Brenchley, Willie Soon
1. “Yesterday, the White House took the position that the Paris climate agreement – a landmark
effort to combat global warming by reducing greenhouse gas emissions – was a bad deal for
America.” [Emphasis added to correspond to our comment.] Reif (2017).
To the best of our knowledge, there is no scientiﬁc basis unambiguously establishing that CO2 is
the main driver of the modest temperature increase observed since the end of the Little Ice Age…
June 16th, 2017 at 11:19 am
May 2017: Global temperature ticks up for 2 months running
A good month for Mr Gore with UAH’s global average temperature ﬁgure almost on the Gore/IPCC
red warming line after two months!in a row of increasing temperatures. This is an uncommon event:
during the 113 months of the bet, so far, temperatures have increased for two months running only
20% of the time.
Runs of temperature increases or decreases are the exception. Three months of increasing
temperatures has only occurred for 6% of the bet months, so an increase again in June would be
even more unusual. By contrast, three months running of falling temperatures has occurred for 9%
of the 113 bet month.
Despite the warmer month, Mr Gore’s cumulative absolute forecast error remains nearly 22%
greater than the error from Professor Armstrong’s Green-Armstrong-Soon no change forecast.
June 7th, 2017 at 12:43 pm
Month 112 of 120 month Climate Bet (April 2017) sees temps
near average, again
April’s UAH temperature anomaly came in at 0.27°C, up from March (0.19°C), but well down on
the 2016 average of!0.5°C. With 8 months of The Climate Bet left to run, we ask again, “how high
would temperatures need to be over the remainder of 2017 for Mr Gore to win The Bet?”
If the temperature anomaly equalled the high for the period of The Bet so far (0.83°C) for the rest of
this year, Professor Armstrong would still win The Bet backing the Green-Armstrong-Soon no-trend
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forecast. In fact, any plausibly extreme warm temperatures over the remainder of 2017 would still
leave Professor Armstrong as the clear winner.
May 23rd, 2017 at 9:01 am
Lindzen on climate alarmism
MIT professor of atmospheric science Richard Lindzen wrote in his April 25 “Thoughts on the
public discourse over climate change”:
Although I have presented evidence as to why the issue is not a catastrophe and may likely
be beneﬁcial, the response is puzzlement. I am typically asked how this is possible. After all,
97% of scientists agree, several of the hottest years on record have occurred during the past
18 years, all sorts of extremes have become more common, polar bears are disappearing, as
is arctic ice, etc. In brief, there is overwhelming evidence of warming, etc. I tended to be
surprised that anyone could get away with such sophistry or even downright dishonesty, but
it is, unfortunately, the case that this was not evident to many of my listeners. I will try in
this brief article to explain why such claims are, in fact, evidence of the dishonesty of the
To read the rest of his op-ed, see here.
May 4th, 2017 at 8:58 pm
Armstrong interview on Earth Day: “Give us your money and
we will save you…”
“A lot of these people that were marching weren’t familiar with the ﬁrst Earth Day in 1970. The ﬁrst
Earth Day said, ‘The science is settled: the Earth is getting colder.’ And the government said, ‘Give
us your money, and we’ll save you,” Armstrong told SiriusXM host Alex Marlow.
“The earth did not get colder. In fact, it got a bit warmer,” he noted. “So money was wasted, people
forgot. But then last Saturday, we’re told once again that this time it’s really settled, and it’s getting
warmer this time. So give us your money, and we’ll save you.”
April 25th, 2017 at 9:49 am
March 2017 cooler than same month 10 years ago
According to the UAH satellite measure of global temperatures the March anomaly, at 0.19°C, was
down from the same month in 2007 (0.26°C), the base year of the Armstrong-Gore “Bet” on
whether dangerous manmade global warming was!a good forecast. Temperatures cooled during
2007, so the March anomaly, while down strongly from the previous month, is still slightly warmer
than the average for the !2007 year, which was a little under 0.16°C.
On the basis of the Green, Armstrong, and Soon (2009)!no change (no trend) forecast, Professor
Armstrong bet that global mean temperatures during the ten years!from 2008 to 2017 would be
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closer to the!2007 average than to the 0.3°C warming trend projected by the U.N. IPCC and Mr
Gore’s alarming “tipping point” rapid rise in global temperatures.
To date, the average monthly signed error of Professor Armstrong’s forecast is -0.01°C. In other
words, the no-trend forecast has been on the high-side as much as it has been on the low side of the
actual global average anomaly. By contrast, Mr Gore’s IPCC stand-in projection has had an!average
monthly signed error of +0.15°C, which suggests a strong bias toward warming.
April 17th, 2017 at 7:40 pm
Global warming forecasts scientiﬁc? “People vs. alarmist
Professor Scott Armstrong presented a talk on this topic by him and Kesten Green at
Heartland’s!Twelfth International Conference on Climate Change (ICCC12) on!March 23 in
The talk asks the question, “Are long-term forecasts of dangerous global warming scientiﬁc?”, and
1. the only 2 papers with scientiﬁc forecasts found no long-term trends
2. IPCC methods violate 81% of the 89 relevant scientiﬁc principles
3. IPCC long-term forecasts errors for 90-100 years ahead were 12 times larger than the no-
4. tests on three other data sets, one going back to 112 AD, found similarly poor accuracy
5. the “long-term global cooling” hypothesis was twice as accurate as the dangerous global
Also “no” because the warming alarm…
6. ignores all 20 of the relevant Golden Rule of Forecasting guidelines; the AGS scientiﬁc
forecasts violated only one
7. violates Occam’s razor
8. fails to comply with any of the 8 criteria for scientiﬁc research
9. fails to provide scientiﬁc forecasts of harm to people
10. fails to provide scientiﬁc forecasts that “solutions” will work
11. fails to meet any of the 10 necessary conditions for successful regulation
12. is similar to 23 earlier environmental alarms supported by the government: all lacked
scientiﬁc forecasts and all were wrong.”
A video of his presentation and a copy of a more complete set of slides!with links to evidence, is
available from here.
April 6th, 2017 at 2:37 pm
February 2017 global average temperature gives Mr Gore’s
chances a lift
After 2 months that saw wins for Professor Armstrong’s bet on no long term!change in global mean
temperatures, the UAH estimate!for February came in at 0.35°C. That was 0.1°C cooler than Mr
Page of 36 152
Gore’s “bet” on the IPCC 3°C per century warming scenario, but 0.2°C warmer than Professor
While Mr Gore’s bet had a run of wins recently—from October 2015 to November 2016—Professor
Armstrong’s scientiﬁc no-change forecast has won 80 of the 110 months of the bet so far. So, while
Mr Gore’s favoured dangerous manmade global warming scenario is looking more credible!than it
has done for almost ﬁve years, the scenario’s!cumulative absolute forecast error to date is still more
than 22% larger than that of the no-change forecast.
The Climate Bet now has only 10 months of its 10 year term to run.
March 6th, 2017 at 11:53 am
Politico-Scientiﬁc establishment rushes to climate alarm
David Rose’s 5 February, 2017, article in the!Mail on Sunday has been receiving a lot of attention
with its reporting of the rushed publication of a NOAA-authored article in the high-status
journal!Science!in order to “inﬂuence the Paris agreement on climate change”. The article’s claim
that there had been no “pause” in global warming was not only at odds with other published data,
we now know that it was based on “misleading, ‘unveriﬁed’ data.”
The Rose article’s headline, “Exposed: How world leaders were duped into investing billions over
manipulated global warming data”, hints at how much is at stake over the climate change issue. The
article is available, here. Professor Judith Curry provides commentary on the commentary in her
blog post titled “Response to critiques: Climate scientists versus climate data”, here. Anthony Watts
has also posted commentary at his Watts Up With That? site that includes!a chart, which will be of
particular interest to Australian readers, that shows raw and adjusted Alice Springs temperature data
since about 1880. A version of the chart is reproduced, below.
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February 8th, 2017 at 12:34 pm
2017 ends on a cooler note: Gore remains less accurate than
no-change after 9 years
We have updated the Climate Bet chart with the December 2016 global temperature anomaly data
from UAH. (Click on the small chart to the right for a more detailed image.)!2016!was a warm El
Niño year, but ended with a sharply cooler month at 0.24°C; somewhat closer to Professor
Armstrong’s no-change forecast of 0.159°C than to Mr Gore’s IPCC dangerous warming trend
ﬁgure for December 2016 of 0.443°C.
With the data in for 9 of the Climate Bet’s 10 years, the cumulative absolute error of the dangerous
warming trend that the IPCC and Mr Gore warned that we should expect is nearly 23% greater than
the error of the scientiﬁc no-change forecast that is the basis of Professor Armstrong’s bet. The no-
change forecast has been more accurate in 78 of the 108 months of The Bet to-date.
Despite 30 months of The Bet in which the warming trend was more accurate, the cumulative error
of the Gore/IPPC dangerous warming projection has been larger!than Armstrong/no-trend forecast
for all but two months of the bet so far.
January 8th, 2017 at 10:50 am
A new lease on life for the climate bet with 14 warmer months
in a row
November 2016: After 14 months of global average temperatures closer to Mr Gore’s warming
scenario!than to Professor Armstrong’s bet on no-trend, the Climate Bet is more in contention than
it has been for the past four!years. Some commentators expectations of a rapid cooling after the
recent warm El Niño months have not so far been realised in global average temperature anomaly.
So, with only 13 months of The Bet remaining, what would need to happen to temperatures over
that time for Mr Gore to win the bet—had he been willing to take it. After November’s 0.45°C
outturn, and a total of 107 months of the bet, Mr Gore’s cumulative absolute error is nearly 21%
greater than Professor Armstrong’s. As a consequence, global temperatures would need to average
higher than they were in November for the remainder of the bet period. Temperature anomalies
have exceeded that level in 9 months of the bet period to date.
Followers of the site may have noticed that we have not posted news items over the past few
months. Please accept our apologies. Having overcome some software and administrative problems,
we expect to be posting updates regularly for the remainder of the bet period.
December 8th, 2016 at 12:19 pm
May, then June, saw big falls in temperature anomalies
From a global average anomaly of 0.71°C for April, temperatures dropped to 0.34°C for June 2016,
two months later. The fall in average temperatures of 0.37°C is the largest two-month decline in the
history of the Armstrong-Gore Climate Bet, and closely matches the record two-month increase of
0.38°C that occurred between December 2015 and February of this year.
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Despite the rapid cooling, June was still relatively warm, and so the month counts as a win for Mr
Gore. He needs temperatures to pick up again rapidly, and stay well up, if he is to have a chance of
winning the bet, which ends at the end of next year.
July 12th, 2016 at 6:01 pm
Regulate the climate?: A new resource on the effects of regs
Advocates of the dangerous manmade global warming hypothesis call for regulations in response to
their alarm. Assume for a moment that the alarmists’ feverish scenarios really were going to come
to pass… would regulations make the situation better?
The Iron Law of Regulation suggests otherwise. For a new site from Kesten Green and Scott
Armstrong that is devoted to experimental evidence on the effects of regulations, see
June 20th, 2016 at 7:34 pm
May 2016 sees temperatures climb down from El Niño peak
The May global average temperature was down by 0.16ºC from!the previous month as the!El Niño
weather system weakened. The 0.55ºC May ﬁgure!was nevertheless still!warmer!than the earlier,
2010, peak in temperatures.!In other words, we have been experiencing the kinds of temperatures
that the dangerous manmade warming alarmists have been warning would be harmful. We wonder
how much additional net!harm (i.e., after allowing for additional beneﬁts) was caused by the
warmer average temperatures over the last six or eight!months?
For a larger view of the updated Climate Bet chart, click on the small chart to the top right of this
June 14th, 2016 at 11:08 am
April ’16: Another month warming Mr Gore’s bet hopes
Last month we noted that if temperatures remained at around the same level as they averaged for
the ﬁrst three months of 2016, Mr Gore could win the Climate Bet. The ﬁgure—global average
temperature anomaly—was +0.7°C.
We didn’t fancy his chances given that the ﬁgure is a high for the satellite record and is!associated
with a strong El Niño weather pattern. The warmth bringing!El Niño weather pattern is followed by
cooling La Niña weather. One month on, however, the April 2016 ﬁgure turned out to be +0.71°C.
We imagine Mr Gore must be overjoyed!
With 20 months of the 10-year bet to go, we still don’t fancy Mr Gore’s chances that!0.7°C
temperature anomalies will continue. We’ll keep you posted.
May 10th, 2016 at 12:20 pm
Earth Day 1970 predictions: Evidence of bias?
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Here’s one: “Demographers agree almost unanimously… thirty years from now,… the entire world,
with the exception of Western Europe, North America, and Australia, will be in famine”. (The
“almost!unanimously” claim might sound familiar to those who have been paying any attention to
the media coverage of the current global warming alarm.)
If you’ve got the stomach for it,!The Daily Caller provides a list of “7 enviro predictions from Earth
Day 1970 that were just dead wrong”. That the alarming!forecasts were so wrong should be of no
surprise to anyone who is familiar with the Golden Rule of Forecasting,!or with Kesten Green and
Scott Armstrong’s study of analogies to the global warming alarm.
The Daily Caller article,!available here, describes the forecasts and the very different outcomes. The
directions of the errors is all in the same direction. A reasonable person might wonder if, in addition
to ignorance of other aspects of good forecasting practice, bias played an important role.
April 23rd, 2016 at 1:01 pm
Gore would win bet, if temperatures stay this warm
While, after 99 months of the Climate Bet, Mr Gore’s forecast errors are 37% larger than Professor
Armstrong’s, it is mathematically possible for Mr Gore to win. For that to happen, however, the
global average!temperature anomaly would have to stay around the average of the ﬁrst three months
of this year, +0.7°C. We will keep you posted!
April 9th, 2016 at 1:57 pm
Five warmer months give bet hope for warmers
We’ve had to adjust the Climate Bet chart to make room for the February 2016 UAH global average
temperature anomaly of +0.83°C above the 1981-2010 average. For!ﬁve months in a row now, Mr
Gore and IPCC’s warming projection was more accurate than Professor Armstrong’s no-change-
from-2007 forecast. The last time Mr Gore got such a run was in 2010, when the IPCC warming
projection was more accurate for the ﬁrst 10 months of the year.
Overall, however, the errors of IPPC projection are still as much as 40% larger than the errors from
the evidence-based forecast of no change.
Mr Gore’s chances of winning the bet must, nevertheless, have improved with the latest ﬁgure. To
put the data!into perspective, if the temperature anomaly remained at or above .437°C for the last 22
months of The Bet—to the end of 2017—Mr Gore would win.
Perhaps Mr Gore!will he change his mind and decide that he would like to put some of his own
money at stake. He should be aware!that the .437°C ﬁgure has only been equaled or beaten 7 times
over the 98 months of The Global Warming Challenge to date, but that statistic will presumably
carry little weight for those who, like Mr Gore, believe in the coming of a!“tipping point”.
March 12th, 2016 at 10:12 am
Why theclimatebet.com uses satellite data – revisit
In a recent (12 February 2016) article, Willie Soon, David Legates, and Christopher Monckton
revisited the topic of measuring global temperatures and explained why satellite measurements are
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superior to terrestrial thermometer measures. For readers who would like a refresher on why it is
that The Global Warming challenge adopted satellite temperature data as the criterion for judging
the outcome of the Armstrong-Gore climate bet, see the Soon, Legates, and Monckton article “What
do we know about CO2 and global atmospheric temperatures”, here.
March 3rd, 2016 at 12:28 pm
Can’t look the other way on persistence of trend-less
The prestigious Nature magazine on 24 February 2016 published online an article recognising the
fact that (looking back) global average temperatures have been trend-less for at least the last 15
years. That’s right, Mr Gore, despite greatly increasing concentrations of atmospheric carbon
dioxide, the various measures agree that there is still no tipping!point!
David Whitehouse, in a 26 February article in the U.K.’s!The Spectator,!suggested that Nature‘s
article!“ought to have been front page news – and might have been, had it suggested that global
warming was worse than we had thought.” Whitehouse’s article, with link to the Nature paper, is
March 1st, 2016 at 9:30 pm
Spikey temperatures: Despite January warmth, spikes have
been more cool than warm
The UAH global average temperature anomaly spiked in January to the warmest it has been during
the 97 months of the bet so far. We have seen similar spikes earlier in the bet period, in early 2010
and January 2013. All three of those spikes were (just) more than 0.3°C warmer than the 2007
annual average, which is the base year of the bet and the no-change forecast that Scott Armstrong is
The three spikes amounted to 5 months in all of temperatures more than 0.3°C warmer than the
2007 annual average.
A glance at the updated chart (right) shows that there have also been downward spikes in the UAH
global average temperature during the period of the bet. In fact there have been six cool spikes
amounting to 8 months of temperatures more than 0.3°C cooler than the 2007 annual average.
Not only have warm spikes been less frequent than cool spikes, in the context of the bet the cool
spikes have been relatively cooler than the warm spikes have been warm. The average cool-spike
temperature was 0.02°C cooler than the 2007 annual average than the average warm-spike
temperature was warmer.
February 24th, 2016 at 4:00 pm
2015 ended on high note for Gore camp, but is it too-little too-
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The short answer is, most likely!it is too late for Mr Gore to win the bet with Professor Armstrong.
Of the eight years of the bet so far, Professor Armstrong’s no-change forecast has been been more
accurate than the Gore/IPCC “dangerous” warming forecast in seven. Looking at individual months,
the no-change forecast has been!more accurate for!72 of 96, or 75%. Overall, the errors of Mr
Gore’s forecasts to date are nearly!42% larger.
To tip the balance of forecast errors back in Mr Gore’s favor, the temperature anomaly would need
to average close to the Gore/IPCC +0.03ºC p.a. trend line.
January 12th, 2016 at 2:26 pm
October-November global temperatures (slightly) warm Paris
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-
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.
December 25th, 2015 at 6:17 am
September 2015 sees continuation of temperature up-and-
The 93 months of the 120 month (10-year) Climate Bet so far has witnessed!45 months in which the
global average temperature anomaly increased from the previous month, and 46 months in which
the global temperature fell. This pattern, or lack of it, is of course consistent with the Green,
Armstrong, and Soon (2009) evidence-based no-change forecast that is the basis of Professor
Armstrong’s notional bet with Al Gore.!For the latest data, click on the chart to the right.
October 20th, 2015 at 12:33 am
With two-thirds of 2015 behind us, we’re averaging .025°C up
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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!
September 16th, 2015 at 2:31 am
July 2015: Global mean temperature continues gentle seesaw
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.
August 10th, 2015 at 1:30 pm
June 2015 temperatures edge up; remain below Gore line
An!up-tick in temperature anomalies in June saw Mr Gore and the warming scenario score the!ﬁrst
win against the no-change forecast since January of 2013, nearly two-and-a-half years ago. The
outlook for the dangerous warming scenario remains bleak, however. Over the 7.5 years of the
Armstrong-Gore Bet so far—we have now past the!¾ mark—the errors that have arisen from
projecting temperature to increase at a rate of 3°C per century are more than 50% larger than the
errors from the no-change forecast.
Is it really possible that the simple no-change forecast of 21st Century temperatures is better than
the IPCC projections from expensive and complex computer models? Yes, it is. That conclusion is
consistent with the evidence presented by Kesten Green and Scott Armstrong in their recently
published review of evidence on the effect of complexity on forecasting. They found that using
complex methods increases forecast errors relative to the forecasts from simple methods that
decision makers could understand by 27% on average. We expect that the results of The Climate
Bet will increase that average.
July 6th, 2015 at 2:09 am
Tenth International Conference on Climate Change
The Heartland Institute’s Tenth International Conference on Climate Change (ICCC 10) took place
in Washington D.C. on the 11th and 12th of June. Scott Armstrong presented a talk based on
research with Kesten Green. Slides of their talk!can be downloaded by clicking!here. A ﬂyer,
summarising their evidence on climate forecasting, with links to relevant papers is available, here.
June 15th, 2015 at 1:27 pm
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May 2015: Now 28 months straight of surprisingly low
temperatures for Mr Gore
While Mr Gore with his expectation of a “tipping point” and the IPCC with their dangerous
warming projection will no doubt be surprised at how low global temperatures have been running,
Professor Armstrong with his scientiﬁc forecast of no long-term trend in temperatures with Green
and Soon will not.
The Armstrong-Gore bet has now been running for 7 years and 5 months (89 months) now, and the
average global temperature anomaly as calculated!from satellite measurement!by!the UAH team has
been 0.12°C. That ﬁgure compares with the 0.17°C average for the base year of the bet, 2007.
That’s right, the average global temperature over the nearly 90 months since the beginning of the
bet has been lower than the average for year the bet is based on.
The non-tipping!point that we have been experiencing for more than seven years leaves Mr Gore’s
bet out in the cold. His average absolute error to date is 0.22°C. That ﬁgure is 55% greater than the
error of Professor Armstrong’s scientiﬁc forecasts. Yes, the scientiﬁc method does work, and can be
relied upon ahead of the opinions of experts (even those of scientists) every time!
June 11th, 2015 at 3:02 am
April data after improved procedures: Chilling news for Mr
The benchmark global temperature data from the researchers at UAH-Huntsville have!been adjusted
to compensate for drifting in the positions of the satellites that take the readings and other
improvements in the measurements and calculations. The!improvements in the data series must be
disconcerting for warming alarmists such as Mr Gore and the IPCC: dangerous warming and a
“turning point” are nowhere to be seen. We hope they are relieved that there is (even less) reason to
believe the Earth is in danger and that governments will realise the folly of policies to reduce
carbon dioxide levels.
Our chart of The Bet to April 2015 is shown to the right of the page, as usual, using UAH’s revised
series. The picture is clear, but for this who prefer numbers, here is a very small one:
0.000000000005. That number (which is roughly equal to 1-divided-by 214!billion) is the
probability that temperatures would have equaled-or-exceeded Mr Gore and the IPCC’s 0.03°C per
annum warming projection!as few or fewer times as the 13-out-of-88 months of The Bet so far that
they have done so… if their projection were unbiased.
For more information on the UAH data revisions, see the description by Spencer, Christy and
May 24th, 2015 at 3:18 am
Why is the Arctic ice still there, Mr Gore? Another failed
Al Gore predicted the Arctic ice cap would be gone by 2014 due to dangerous manmade global
warming. The evidence is in: ice extent is!up!somewhat compared to the extent!when!satellite
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monitoring began in 1979. Professor Armstrong reminds readers of a May 20 article in The New
American that there are no scientiﬁc forecasts that give credence to claims that dangerous global
warming will occur. The article, titled “NASA’s own data discredits its predictions of Antarctic
Doom”, is available here.
If Mr Gore really wants to make forecasts that are more accurate, he should learn!the Golden Rule
of Forecasting. By following the guidelines in the Golden Rule Checklist, he can avoid biased
forecasting procedures that can cause forecasts to be less accurate than guessing. For more
information on the Golden Rule, and to get a copy of the checklist of guidelines, see
May 21st, 2015 at 4:47 am
Climate consensus? What climate consensus?
An oft repeated climate forecasting claim is that 97% of scientists agree that there is a problem of
dangerous manmade global warming and that human emissions of carbon dioxide must be
drastically curtailed in order to avoid disastrous consequences. If that claim sounds unlikely to you,
as well as being irrelevant, you are right. Professor Ross McKitrick—a scientiﬁc Toto to the
climate-alarmist Wizard of Oz—dissects the claim and exposes!its lack of substance in his May 11
article in the Financial Post titled, “The con in consensus.”
May 17th, 2015 at 4:34 am
Cooling March follows February down
We have been slow to get the chart up for The Climate Bet results to March 2015. It is up now!
Click on the thumbnail chart to the right for the full-sized image and data table. With the April
global mean temperature reading only days away, will save our analysis and commentary until then.
April 30th, 2015 at 1:07 pm
Inquiry into global temperature data integrity announced
The London-based think-tank the Global Warming Policy Foundation !announced!on 26 April 2015
a major inquiry into the integrity of the ofﬁcial global surface temperature records. Questions have
been raised about the reliability of the surface temperature data and the extent to which apparent
warming trends may be artefacts of adjustments made after the data are collected.
The inquiry will review the technical challenges in accurately measuring surface temperature, and
will assess whether the adjustments to the data are biased and, if so, to what effect. For more
information, or!to make a submission, see here.
April 27th, 2015 at 1:42 am
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Doubt merchants, or truth warriors? Battle of the
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).
April 17th, 2015 at 10:00 pm
La Stampa interviews Armstrong on Gore bet
The Italian newspaper La Stampa!published an Alain Elkann Interview of Scott!Armstrong
on!Sunday April 12 titled “J. Scott Armstrong: “Vi spiego perché le previsioni sul clima sono
sbagliate””!here. Alain was particularly interested to know about the subject of theclimatebet.com:
Professor Armstrong’s challenge to Al Gore to bet that temperatures will increase dangerously, as
Mr Gore has threatened will happen.
Regular readers of this blog will be familiar with the Challenge, but for those of you who are not, or
who are interested to read a fresh summary of what scientiﬁc forecasting tells us about 21st Century
temperatures, you can ﬁnd the full interview in English on Alain Elkann’s own site here. For those
of you who have friends who are struggling to make sense of the dangerous manmade global
warming alarm, the interview is a good place to start.
April 13th, 2015 at 5:08 am
Can’t fault the science? Attack the scientist
March 2015 saw a new low in public discourse about what changes, if any, to expect in climate over
the 21st!Century with The New York Times running a high-proﬁle article attacking a scientist who is
skeptical about the dangerous manmade global warming alarm. The article suggested that the
scientist, Dr Willie Soon, should have provided information about his employing institution’s
funding arrangements. Say what?
Was the article part of a larger investigation by!NYTimes reporters that found that all scientists
routinely report the details of their institutions’ funding, and any other arrangements or relationships
that readers of their papers might ﬁnd interesting… except Willie Soon? If they did, they must have
forgotten to mention that!in their article.
Is there any reason that Dr Soon was singled out for this “special” treatment, other than the
unpopularity of his conclusions about!the global warming alarm with the!NYTimes!reporters and
their friends in alarm? We can’t think of any.
It appears that the alarmists are alarmed that the wider public are no longer alarmed. They!have no
response in science, and so resort to personal attacks.
In his recent article in The Washington Times, Professor Scott Armstrong challenges those who still
fear global warming to test whether their fears are justiﬁed by following good scientiﬁc practice,
and replicate the research that they ﬁnd so unsettling. Perhaps their ﬁndings would be different.
Now that would be a story!
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Scott Armstrong’s Washington Times article, titled “Missing the mark on climate change skepticism:
It’s not about the money, it’s about the science”, is available here.
March 28th, 2015 at 12:52 pm
86 months on, and still no “tipping point”
With 86 months of the 120 month Climate Bet behind us, we are still waiting for the “tipping
!point” Mr Gore promised us. We hope you haven’t been holding your breath, or planted bananas in
your wheat ﬁeld. While the actual temperature has been cooler!than Professor Armstrong’ no-
change forecasts for more than!half of all bet months (51%), the Gore-IPCC forecasts ran hotter
than the actual!temperature for 81% of months to date.
March 11th, 2015 at 11:41 am
January 2015 warms Mr Gore’s prospects
The global average average temperature anomaly ticked up a tad to reach 0.36°C in!January, enough
to get past half-way to the IPCC “dangerous warming” trend line that is standing in for Mr Gore’s
bet. Mr Gore has now won 26 out of the 85 months of The Climate Bet so far; less than half of the
59 months that Professor Armstrong has won. We hope that Mr Gore wins a few more months to
keep The Bet alive!for the remaining nearly three years that are left to run.
February 11th, 2015 at 12:17 pm
Why we don’t use IPCC temperatures for The Bet: An update
In case you, and we, needed reminding, Christopher Booker describes the latest stories!to break on
the dubious adjustments and revisions that government agencies make to the sparse measured
terrestrial temperature record in his The Telegraph article titled “The ﬁddling with temperature data
is the biggest science scandal ever.”! The adjusted data!are used to derive the!global average
temperature series used by the IPCC and others who promote warming alarmism.
Reading Booker’s article leaves the reader!with the impression that the use of the term “ﬁddling” in
the title amounts to a classic case of British understatement. The term “rewriting history” is perhaps
closer to summarising the violence that!is still being done to the ofﬁcial temperature records.
A picture is sometimes worth a thousand words. Steven Goddard’s changing temperature history
charts on this page of his blog very effectively illustrate some of the adjustments that have been
made to the ofﬁcial series. It is possible, one might suppose, that better data might become available
decades or even centuries after the event, or that better methods for analysing data might be
developed. But such developments would not explain why every round of adjustments to!the older
data has resulted in a stronger warming trend.
February 9th, 2015 at 6:04 am
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Who is more accurate, the global coolers or the global
Kesten Green and Scott Armstrong tested the predictive validity of the United Nations’ IPCC global
warming hypothesis of +0.03°C per year due to increasing CO2 against the relatively conservative
hypothesis of natural global cooling at a rate of -0.01°C per year. The errors of forecasts from the
global warming hypothesis for horizons 11 to 100 years ahead over the period 1851 to 1975 were
nearly four times larger than those from the global cooling hypothesis.
Forecasts from the no-change model, however, were substantially more accurate again than those
from the global cooling hypothesis. Findings from their!tests covering a period of nearly 2,000
years support the predictive validity of the no-change hypothesis for horizons from one year to
centuries ahead (Green and Armstrong, 2014). A pre-publication draft of their “Forecasting global
climate change”!chapter!is available, here.
Green,!K. C.!& Armstrong, J. S. (2014).!Forecasting global climate change. In Moran, Alan
(ed.).!Climate Change: The Facts 2014, pages 170-186.!Published by the Institute of Public Affairs,
Melbourne, Victoria 3000, Australia.
January 28th, 2015 at 3:02 am
Global temperatures: Seven years of Sideways
It may be hard to believe with!the rhetorical bombardment of the warming alarmists and their
supporters in the media that we are exposed to, but global average temperatures over the last seven
years!averaged!less than the 2007 base year of the Armstrong-Gore bet. Yes, you did just read that!
The average of the monthly temperature anomalies in 2007—as calculated!by the University of
Alabama at Huntsville scientists!from satellite observations—was 0.21°C. The average for the
seven years since then was!0.20°C.
That doesn’t seem like a tipping point, Mr Gore!
The updated graph, to the right, shows not a tipping point, but lots of turning points. The net
result?!You guessed it, a sideways drift that is just what followers of this site!and the evidence-
based Green, Armstrong, and Soon no-trend forecast!would expect.
January 16th, 2015 at 12:03 am
New Book “Climate Change: The Facts 2014”
The Institute of Public Affairs have published a collection of works on the physics, economics, and
the politics of climate change (a.k.a. the alarm that dangerous manmade global warming is and will
continue to occur.) The 21 chapters by leading researchers and commentators include Willie Soon’s
“Sun shunned”, and Kesten Green and Scott Armstrong’s “Forecasting global climate change”. The
book is available, here.!We suggest sending!Mr Gore!a copy.
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Update: Kindle versions of Climate Change: The Facts 2014 are now available on Amazon. Either
search Amazon.com for the title or click the!link to the book on your country’s Amazon site from
the following list: US, UK, CA, AU, DE, FR, ES, IT, NL, JP, BR, MX, IN.
January 6th, 2015 at 3:14 am
Environmentalist predictions gone wrong
A small pleasure of the passing of time is that another!batch of unscientiﬁc long-term predictions
comes to full term and are exposed for what they always were: worthless. Fox News’s Maxim Lott
has this New Year provided the service of reminding us of “Botched environmental predictions for
2015”. The ﬁrst of the list is “UN overestimated global warming by 2015”. Another treat is “Arctic
sea ice will disappear by 2015”. Maxim Lott’s article is available here.
There seems to be an endless supply of unscientiﬁc environmentalist alarms, as the Global Warming
Analogies Forecasting Project has identiﬁed, here. Why? In part because forecasters
of!environmentalist catastrophes ignore the Golden Rule of Forecasting and assume that things are
different now. In other words, they ignore cumulative knowledge about the situation they are
making forecasts about, and about forecasting, in order to make extreme predictions. For more
information on the Golden Rule of Forecasting, see goldenruleofforecasting.com. If you don’t have
the time to check out the Golden Rule, remember to treat forecasts of dramatic
unprecedented!changes!in the same way you would treat last week’s newspaper horoscope.
January 3rd, 2015 at 6:30 am
IUCN ﬁnds polar bear scientists’ models unsuitable for
We imagine that Barbara Boxer will be particularly pleased that she did not respond to Professor
Armstrong’s 2008 challenge to back her belief that the polar bear population was threatened with
rapid decline by accepting his bet, based on scientiﬁc forecasting in Armstrong, Green, and Soon
(2008), that polar bear numbers would remain at current levels or better.
It seems that modellers at the International Union for the Conservation of Nature agree with
Armstrong, Green, and Soon that the models of polar bear biologist Steven Amstrup and colleagues,
upon which Senator Boxer based her belief, are not ﬁt for the purpose of forecasting the polar bear
population. For more on this story see the article titled “Amstrup knows his polar bear predictions
are ﬂawed – but continues to promote them” on the polarbearscience.com site, here.
December 7th, 2014 at 12:05 pm
With November data in, 2014 looks warmer than 2013, but
much cooler than 2010
Looking only at the nearly 7 years of The Climate Bet, with one month of 2014 to go any talk of
record warmth looks to be a big stretch. For the average temperature anomaly for 2014 to exceed
the relatively warm 2010 average, !December’s anomaly would need to come in at an
unprecedented 2°C or higher. We think Mr Gore and the IPCC should not count their chickens
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before they’ve hatched. For the latest graph and numbers on the Bet, see the updated chart to the
December 6th, 2014 at 7:02 am
Is it possible that global warming is a political phenomenon?
Wouldn’t it be strange if what counted as science was determined by the political ideologies of
academics? Yet that is what an October 30 article in The New Yorker suggests.
Maria Konnikova’s article, here, describes the considerable evidence that !university academics,
who control hiring and publication decisions, are so burdened by bias as to reject all evidence that
conﬂicts with their predominantly left-liberal-internationalist ideology.
Perhaps that explains why the hypothesis of trend-less natural change in global mean temperatures
is not widely accepted as being the most obvious and well-supported description of long-term
climate among much of the academic community.
November 2nd, 2014 at 11:40 am
Are forecasts of a 2014 global temperature record believable?
Based on NOAA ﬁgures for August 2014, Discover magazine posted an article online on September
19 with a headline making a dramatic forecast that, “With Summer’s Unequalled Warmth, 2014 is
Likely to Finish as the Warmest Year on Record for the Home Planet”. AOL ran a piece on October
20 making the same forecast, this time backed with an extra month of NOAA data and the support
of a claim by a NOAA scientist that “it’s pretty likely”!that 2014 will see the global average
temperature record broken… for the years since records began in 1880.
Climate scientist Roy Spencer begs to differ in his blog post titled “Why 2014 won’t be the warmest
year on record“. Dr Spencer prefers the UAH satellite data record, pointing out that it, as opposed to
NOAA’s adjusted and patchy thermometer data series, the satellite data provides a truly global and
objective measure of temperatures. The Global Warming Challenge uses the UAH series as the
measure for determining who will win the Armstrong-Gore bet for that reason.
We will post the outcome of the Spencer-NOAA conﬂicting forecasts when the data are ﬁnalised
early in 2015. [See NOAA versus Spencer for their different takes on the 2014 outcome.]
October 27th, 2014 at 2:31 am
Gore bet looks vulnerable with less than one-third to run
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.
October 22nd, 2014 at 6:35 am
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August 2014 fails to warm
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.
September 9th, 2014 at 4:47 am
July temperatures sideways as Gore error trajectory continues
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.
August 16th, 2014 at 2:33 pm
Mr Gore’s tipping point forecast either biased, or very
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-
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.
June 16th, 2014 at 2:41 am
If “consensus” is evidence for alarm, what evidence its
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 desperate nature of resorting to a vote to decide how the Earth’s climate will
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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.
May 29th, 2014 at 5:05 am
April 2014: Cooling better bet than dangerous warming
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!
May 14th, 2014 at 1:54 am
March 2014 temperatures: More evidence on Gore warming
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.
April 10th, 2014 at 6:25 am
February 2014, and temperatures continue to oscillate around
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.
March 11th, 2014 at 11:16 pm
Climate alarmists willing to bet on the ﬂip of a coin
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.
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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.
January 20th, 2014 at 11:29 am
The Climate Bet is 6 years old, and temperatures are still
going up, and down
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 catastrophic
“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.
January 9th, 2014 at 7:16 am
Armstrong and Green on climate models in NIPCC’s Climate
Change Reconsidered II
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
The reference is as follows, and links to the relevant section of the NIPCC report are available from
Armstrong, J. S., & Green, K. C. (2013). Global climate models and their limitations: Model
simulation and forecasting – Methods and principles. pp. 15-18 in Idso, C. D., Carter, R. M., &
Singer, S. F. (Eds.), Climate Change Reconsidered II: Physical Science. Chicago, IL: The Heartland
December 21st, 2013 at 11:32 pm
Can Mr Gore win the sixth year of The Bet?
With eleven months of temperature data now in for 2013, it is highly unlikely that Mr Gore could
win this, the sixth, year of The Climate Bet. For Mr Gore to win, the December global mean
temperature anomoly would need to be substantially higher than any month so far in The Bet.
Failing that unlikely outcome, the no-change forecast that Professor Armstrong is betting on will
have been more accurate that Mr Gore’s IPCC-originated dangerous manmade global warming
forecast for ﬁve of the ﬁrst six years of The Bet.
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December 10th, 2013 at 3:01 am
Is Mr Gore’s red line a biased forecast?
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
November 17th, 2013 at 11:26 pm
LA Times censors skeptics
The LA Times!letters editor has apparently decided that they know The Truth in scientiﬁc matters
and will not let anything else besmirch 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.
October 20th, 2013 at 7:12 am
Financial Post gives voice to scientiﬁc climate forecasting
“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 ﬁnal draft of 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.
October 10th, 2013 at 4:11 am
Dance of temperatures sees warmer September
The September global temperature anomaly was the highest it’s been since January, and is close to
Mr Gore’s “forecast” for the month. The balance of the bet remains ﬁrmly in Professor Armstrong’s
favour, however: The error of the red-hot alarmist projection is to date nearly 20% higher than the
error from the scientiﬁc cool-green no-trend forecast.
October 10th, 2013 at 3:47 am
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New scientiﬁc report on climate change
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
October 3rd, 2013 at 6:25 am
August 2013: Temperatures continue to conspire against
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.
September 12th, 2013 at 12:52 am
Talks on climate forecasting from Doctors For Disaster
The Doctors for Disaster Preparedness Conference in Houston (July 12 to 15 2013) featured several
talks related to the dangerous manmade global warming alarm, including one from
theclimatebet.com’s Professor Scott Armstrong. A video of his talk, “Evidence-Based Forecasting
for Global Warming”, is available here. Willie Soon’s talk, “Five or more failed experiments in
measuring global sea level change”, is available here, and Antony Watts’s talk, “Ten tests to
determine whether you should be concerned about global warming” is available here.
August 17th, 2013 at 1:29 am
Cool July: Temperatures, they are a-changin’… back
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
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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.
August 7th, 2013 at 12:37 am
Armstrong and Soon at Doctors for Disaster Preparedness
Scott Armstrong and Willie Soon both spoke on long-term climate forecasting—Armstrong on
temperatures and Soon on sea levels—on 13 and 14 July 2013 at the Doctors for Disaster
Preparedness Meeting in Houston, Texas. Scott Armstrong’s talk was titled “Evidence-based
forecasting for global warming” and the slides are available here. Willie Soon’s talk was titled “Five
or more failed experiments in measuring global sea level change” and a video recording of it is
Both scientists describe how alarming forecasts have been derived for these poorly understood
situations using complex mathematical models with many variables and judgmental adjustments.
These procedures violate The Golden Rule of Forecasting, which requires forecasters to be
conservative, especially in the presence of great uncertainty.
August 1st, 2013 at 8:01 am
Revised temperature series and June 2013 temp
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, 0.005°C more accurate.
August 1st, 2013 at 6:37 am
Perhaps it would have been fairer to Mr. Gore…
The May 2013 data has been released and shows the monthly temperature anomaly was below the
2007 average that is the starting point of the Armstrong-Gore graph for the fourth month running.
So far, the total error of Mr Gore’s warming forecast is 21% larger than the error of Professor
Armstrong’s no-change forecast.
It occurred to us that the bet would have been fairer to Mr Gore and the IPCC if we had used the
data that were available to Mr Gore when he released his movie “An Inconvenient Truth”, during
2006, as the base-year for The Bet. (The base year that we use for The Bet, 2007, was the most
recent data available when Professor Armstrong issued his challenge to Mr Gore.) And so we re-ran
The Bet using the 2005 average (the latest full year available to Mr Gore when he released his
movie) as the base year. Mr Gore’s forecast in the re-run is for a 0.03ºC p.a. increase from the 2005
average and Professor Armstrong’s is simply the 2005 average.
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In the event, re-running The Bet from 2008 to date using 2005 as a base results in a total error for
the Gore/IPCC alarming warming forecast that is 31% larger than the error of the no-change
forecast. We think Mr Gore would likely prefer to stick with the current Bet arrangement, even
though it is not as fair.
June 6th, 2013 at 1:41 am
Cooler April another challenge for warming alarmists
After spiking in January, temperatures in April were again well below the 2007 average that is Scott
Armstrong’s forecast. 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.
May 7th, 2013 at 2:11 am
No-global-warming best bet for 55 months of 63 so far
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.
April 9th, 2013 at 2:46 am
Changes in the Sun mean changes in the climate
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.
March 14th, 2013 at 12:19 am
Temps drop below 2007 bet benchmark again in February
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”
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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
March 11th, 2013 at 11:44 pm
A ﬂicker of hope for Mr Gore’s bet with the new year
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
March 1st, 2013 at 11:09 am
Armstrong wins two-thirds of months at halfway point of 10-
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].
January 10th, 2013 at 5:30 am
Mr Gore’s temperature rocket again falls short of forecast
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
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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.
December 18th, 2012 at 4:17 am
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.
November 27th, 2012 at 5:43 am
“Science drives out pseudoscience”
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 1 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.
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Prof. J. Scott Armstrong
University of Pennsylvania
November 17th, 2012 at 9:38 am
Rebounding from early 2012 lows, temperatures approached
the Gore line
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
November 13th, 2012 at 5:11 am
Correction for drifting satellite increases Armstrong lead
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.
October 19th, 2012 at 8:49 am
Where’s the warming, Al?
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.
October 16th, 2012 at 3:57 am
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What’s happening to the “other” arctic ice?
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.
September 20th, 2012 at 3:44 am
Spot the Sun’s effect on climate
In a 6 September piece in The Washington Times, Willie Soon and William Briggs bring the long
history of research on the connection between solar activity and Earthly temperatures up-to-date.
We have reproduced the chart that appears in the article, below. For more on the relationship
between the solar radiation hitting the Earth and maximum daytime temperatures, see the article,
here. It is not obvious that carbon dioxide, the gas behind Al Gore and the IPCC’s dangerous
manmade global warming alarmism, could explain any more of the variation in temperatures than is
apparently already explained by the Sun.
September 7th, 2012 at 9:31 am
July: 2012 continues similar to 2011, cooler than 2010
Despite some excitement about locally high temperatures, in the U.S. in particular, the average
global temperature anomaly is, so far this year, much the same as 2011’s at 0.16°C compared to
0.15°C. Compared to 2010, with an annual average anomaly of 0.41°C, most of the world is
experiencing a relatively cool year.
August 7th, 2012 at 8:56 am
Fun Climate Forecasting Quiz
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.
July 20th, 2012 at 11:07 am
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Mr Gore closer on 23 of 54 weeks to June
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%.
July 13th, 2012 at 3:23 am
Polar bears thrive: A surprise for Boxer Committee, which
preferred alarm to scientiﬁc forecasts
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 theclimatebet.com, 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 as follows…
April 9, 2008
The Honorable Barbara Boxer
Chairman, Committee on Environment and Public Works
United States Senate
Washington, D.C. 20510
Dear Senator Boxer,
Since presenting the presentation of my testimony on the validity of the government polar bear
forecasts at your U.S. Senate Environment and Public Works Committee hearing on January 30 of
this year, I along with my co-authors Kesten Green of the University of South Australia and Willie
Soon of the Harvard-Smithsonian Center for Astrophysics, have continued to work on our research
paper on the methods that were used to make the forecasts. Thanks to extensive peer review, we have
made many improvements. I enclose a copy of the paper. […]
I am pleased to inform you that it has now been accepted (subject to further revisions) by Interfaces.
Thus, it stands as the only peer-reviewed study on polar bear forecasting that has been accepted for
We found the forecasts of declining polar bear numbers contained in the government’s administrative
reports were not the product of scientiﬁc forecasting methods. Given the large current population of
bears and the upward trend in the population, our ﬁndings lead to the conclusion that there is no
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scientiﬁc basis for listing polar bears. Indeed, a reliance on evidence-based forecasting suggests that
it is more likely that the polar bear population will increase rather than decrease.
I would be happy to discuss the details of our paper with you.
Professor J. Scott Armstrong, The Wharton School
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
“Healthy polar bear count confounds doomsayers” (April 4, The Globe and Mail) here.
April 9th, 2012 at 7:26 am
Still no sign of dangerous warming
We are still waiting for the dangerous warming that Mr Gore and the United Nations’
Intergovernmental Panel on Climate Change promised us was already happening. With the satellite
temperature data in for the month of March (see the bet-tracker graph to the right) we have had six
months in a row of temperatures below the 2007 average upon which Scott Armstrong’s bet was
based. Armstrong remains ahead overall, and the prospect of dangerous warming during the period
of the bet looks increasingly remote.
April 6th, 2012 at 9:59 am
2012 starts with a walk on the cold side
With global mean temperatures again below the 30-year average, forecasts of manmade CO2
warming and drought must be looking doubtful even to the casual observer as she trudges through
the snow in Europe or the US, or wonders what happened to summer in Australia. Indeed, when
people with open minds are told they will have to pay, they start to pay attention and take the
trouble to assess the evidence themselves. The Auditor General found that Australians weren’t
persuaded by their government’s desperate attempts to convince them that making their energy
expensive was a good idea.
February 8th, 2012 at 11:24 pm
Gore trails after 4 lively years of warming bet
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
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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.
Theclimatebet.com 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.
January 10th, 2012 at 4:16 am
Temperatures remain below 2007 bet benchmark
With November’s temperature anomaly at 0.12, the Global mean temperature was below the 2007
benchmark for The Climate Bet, and Armstrong’s forecast, for a second month running. See the
graph updated with November data on the right.
December 21st, 2011 at 5:11 am
Cooler than when we started
After three months of cooling, the global mean temperature anomaly for October was lower than the
Climate Bet benchmark 2007 average. Atmospheric carbon dioxide levels have continued to rise.
November 11th, 2011 at 12:10 am
Temperatures down two months running
We have now, belatedly, updated the Armstrong-Gore Bet Graph (to the right). The four month spell
of increasing global temperature anomalies earlier in the year petered out and we have now had two
months of global average temperature decline. Since the beginning of 2007, temperatures have
declined relative to the previous month 52% of the time. The longest run has been 6 months of
declining temperatures, while the longest run of increasing temperatures has been 4 months.
October 31st, 2011 at 12:50 am
Warm August keeps Gore’s hopes alive
The last three months have seen a revival of Mr Gore’s hopes of winning the notional Climate Bet,
with global mean temperatures more than 0.3 degrees Centigrade warmer than the 30-year average.
We’ve seen higher, and lower, temperatures before in the !course of the bet however and, with more
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than six years to run and with the actual temperature close to Armstrong’s forecast for 25 out of the
43 months to date, the bet is still very much alive.
September 12th, 2011 at 1:16 am
July UAH temperatures up
Global temperatures are back up to the level they were at the beginning of 2007… before they
dropped below the 1981-2010 average for most of 2008. We don’t know where average
temperatures (anomalies) will go next, but we do know that the Gore-Armstrong Bet is still very
August 10th, 2011 at 7:03 am
Krugman hides behind ad hominem jabs to avoid climate
We didn’t post this story at the time, but it is too good not to share more widely. On March 31, Scott
Armstrong gave testimony to the U.S. Congressional Subcommittee on Energy and Environment on
research to date on forecasting for the manmade global warming alarm. The event drew comment
from New York Times columnist and Nobel Economics Laureate Paul Krugman on April
3.!Professor Krugman made a play of ﬁnding it humorous that a leading expert on forecasting
would be asked to testify on forecasting climate.
Our favorite quote from Krugman’s column is “… let’s talk a bit more about that list of witnesses,
which raised the same question I and others have had about a number of committee hearings held
since the G.O.P. retook control of the House — namely, where do they ﬁnd these people?”
Perhaps Professor Krugman should get out more and meet some of the many scientists and the
majority of voters who have realized that the dangerous manmade global warming alarm is simply
The New York Times published our letter of response on 10 April. Here is the text:
A Forecasting Expert Testiﬁes About"Climate Change
To the Editor:
In “The Truth, Still Inconvenient” (column, April 4), Paul Krugman begins with a
“joke” about!“an economist, a lawyer and a professor of marketing” walking into a
room, in this case to!testify at a Congressional hearing on climate science.
I am the marketing professor, and I was invited to testify because I am a forecasting
expert.!With Dr. Kesten C. Green and Dr. Willie Soon, I found that the global warming
alarm is based!on improper forecasting procedures. We developed a simple model that
provides forecasts that!are 12 times more accurate than warming-alarm forecasts for 90
to 100 years ahead.
We identiﬁed 26 analogous situations, such as the alarm over mercury in ﬁsh.
Government!actions were demanded in 25 situations and carried out in 23. None of the
alarming forecasts!were correct, none of the interventions were useful, and harm was
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caused in 20.!Mr. Krugman challenged 2 of the 26 analogies, “acid rain and the ozone
hole,” which he said!“have been contained precisely thanks to environmental
regulation.” We are waiting for his!evidence.
“What’s the punch line?” he asked. I recommended an end to government ﬁnancing
for!climate change research and to associated programs and regulations. And that’s no
J. SCOTT ARMSTRONG
Philadelphia, April 6, 2011
The writer is a professor at the Wharton School, University of Pennsylvania.
July 20th, 2011 at 7:28 am
June temps crept over the Gore line, but no-change forecast
After ﬁve months below the no-change forecast, temperatures have crossed the Al Gore forecast
line. See the graph of actual temperature to June 2011 and the history of the bet with Scott
Armstrong, to date, in the column on the right. Remember, you can click the graph to get a bigger
image for closer inspection.
July 19th, 2011 at 4:51 am
April and May 2011 temperatures added to graph
Global mean!temperatures (more correctly, global mean!temperature anomalies) for April and May
2011 have been added to our bet chart at top right. After three months at or below the 1981-2010
baseline, April and May were 0.12°C and 0.14°C above the baseline. Temperatures remained below
the 2007 mean that Scott Armstrong offered to bet on, however, as they have done since the
beginning of 2011. As a consequence, the errors to date from the forecasts that represent the
pronouncements of Al Gore and the IPCC are in total 1.8% larger than those from the Armstrong
As we have pointed out before, while Armstrong’s bet is based on evidence-based principles and
Gore’s is not,!10 years is a short time period for bets about the climate and so the chance of a
reversal are not much less than 50%.
June 14th, 2011 at 12:06 am
Economics prof offers bet on weather deaths forecast
In a response to environmentalist Bill McKibben’s assertion in the Washington Post that severe
weather was becoming more common and more severe as a consequence of human CO2 emissions,
Donald Boudreaux of GMU pointed out in the Wall Street Journal that there has been no clear trend
in severe weather and, more importantly, deaths in the U.S. have declined in recent decades despite
an increasing population.
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Boudreaux argues that the trend of fewer deaths is consistent with economic theory and much
evidence that people are creative and resourceful in market economies and that this creativity and
resourcefulness drives adaptions that result in people living longer.
So conﬁdent is Boudreaux in extrapolating this trend, that he has offered to bet McKibben, or Al
Gore or Paul Krugman, $10,000 that “the average annual number of Americans killed by these
violent weather events from 2011 through 2030 will be lower than it was from 1991 through 2010”.
A copy of the concluding paragraphs of Boudreaux’s WSJ column is here.
June 13th, 2011 at 2:13 am
No change in polar bear population
The Polar Bear Specialist Group of the International Union for the Conservation of Nature (IUCN)
has reported that there was no change in the polar bear population in the most recent four-year
The ﬁnding is consistent with the conclusion of a 2008 paper by Scott Armstrong, Kesten Green,
and Willie Soon (“Polar Bear Population Forecasts: A Public-Policy Forecasting Audit”) that “the
inconsistent long-term trends in the polar bear population suggest that it is best to assume no trend
in the long-term.”
The polar bear population ﬁnding contrasts with Senator Boxer’s hearings in January 2008 in which
she expressed the view that the number of polar bears would decline rapidly. Professor Armstrong
offered to bet her that the number of polar bears would not decline, but she did not respond to the
The Polar Bear group’s report can be found here.
The Armstrong, Green, and Soon paper on polar bear population forecasts can be found here.
May 22nd, 2011 at 11:52 pm
March another colder than usual month
We have updated our Climate Bet graph (right) with the latest data from UAH. After 39 months of
the bet, Armstrong’s scientiﬁc forecast has been more accurate than “Al Gore’s” IPCC forecast for
59% of the forecasts.
April 12th, 2011 at 12:52 pm
Testimony on climate change to Congressional Science
Research on Forecasting for the Manmade Global Warming Alarm
Testimony to Committee on Science, Space and Technology Subcommittee on Energy and
Environment on “Climate Change: Examining the processes used to create science and
policy” – March 31, 2011
Professor J. Scott Armstrong, University of Pennsylvania, with Kesten C. Green, University
of South Australia, and Willie Soon, Harvard-Smithsonian Center for Astrophysics
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The validity of the manmade global warming alarm requires the support of scientiﬁc
forecasts of (1) a substantive long-term rise in global mean temperatures in the absence of
regulations, (2) serious net harmful effects due to global warming, and (3) cost-effective
regulations that would produce net beneﬁcial effects versus alternatives policies, including
Without scientiﬁc forecasts for all three aspects of the alarm, there is no scientiﬁc basis to
enact regulations. In effect, the warming alarm is like a three-legged stool: each leg needs to
be strong. Despite repeated appeals to global warming alarmists, we have been unable to
ﬁnd scientiﬁc forecasts for any of the three legs.
We drew upon scientiﬁc (evidence-based) forecasting principles to audit the forecasting
procedures used to forecast global mean temperatures by the Intergovernmental Panel on
Climate Change (IPCC)—leg “1” of the stool. This audit found that the IPCC procedures
violated 81% of the 89 relevant forecasting principles.
We also audited forecasting procedures, used in two papers, that were written to support
regulation regarding the protection of polar bears from global warming —leg “3” of the
stool. On average, the forecasting procedures violated 85% of the 90 relevant principles.
The warming alarmists have not demonstrated the predictive validity of their procedures.
Instead, their argument for predictive validity is based on their claim that nearly all scientists
agree with the forecasts. This count of “votes” by scientists is not only an incorrect tally of
scientiﬁc opinion, it is also, and most importantly, contrary to the scientiﬁc method.
We conducted a validation test of the IPCC forecasts that were based on the assumption that
there would be no regulations. The errors for the IPCC model long-term forecasts (for 91 to
100 years in the future) were 12.6 times larger than those from an evidence-based “no
Based on our own analyses and the documented unscientiﬁc behavior of global warming
alarmists, we concluded that the global warming alarm is the product of an anti-scientiﬁc
Having come to this conclusion, we turned to the “structured analogies” method to forecast
the likely outcomes of the warming alarmist movement. In our ongoing study we have, to
date, identiﬁed 26 similar historical alarmist movements. None of the forecasts behind the
analogous alarms proved correct. Twenty-ﬁve alarms involved calls for government
intervention and the government imposed regulations in 23. None of the 23 interventions
was effective and harm was caused by 20 of them.
Our ﬁndings on the scientiﬁc evidence related to global warming forecasts lead to the
1. End government!funding!for climate change research.
2. End government funding for research!predicated on global warming (e.g., alternative
energy; CO2 reduction; habitat loss).
3. End government programs and repeal regulations predicated on global warming.
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4. End government support for organizations that lobby or campaign predicated on global
April 5th, 2011 at 3:43 am
Climate bet graph updated
We have posted an update of our graph summarizing the history of The Climate Bet between Scott
Armstrong and Al Gore (see right). Global temperatures were again below 2007 average levels.
March 14th, 2011 at 6:31 am
Atmospheric CO2 was up in January and temperatures down:
The latest, January 2011, temperature date is displayed in our updated Climate Bet graph at right.
Neither our graph representing the period of the bet, nor the full satellite temperature series graph
compiled by Roy Spencer provide evidence of alarming warming.
Does that mean that atmospheric carbon dioxide concentrations are falling, as would be consistent
with the Al Gore’s and the IPCC modellers’ previously expressed beliefs?
(They did tell us that people need to reduce their CO2 emissions in order to stop the global average
temperature from increasing dangerously, didn’t they?)
NOAA’s data shows that atmospheric CO2 increased in January, as it has been for the duration of
the NOAA record.
We suggest that disinterested and unbiased observers will wonder whether CO2 changes are really
such an important inﬂuence on climate as Mr Gore would like to have us believe. They might
further wonder how costly policies to reduce CO2 emissions can possibly be justiﬁed.
February 14th, 2011 at 2:24 am
Letter to Congress asks members not to be alarmed, but to be
reassured by the evidence
On the 8th of February 2011, 36 scientists wrote to Congress to challenge the alarming predictions of
dangerous manmade global warming made in an earlier (28 January) letter from 18 scientists. Here
is the text of their letter:
February 8, 2011
To the Members of the U.S. House of Representatives and the U.S. Senate:
In reply to “The Importance of Science in Addressing Climate Change”
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On 28 January 2011, eighteen scientists sent a letter to members of the U.S. House of
Representatives and the U.S. Senate urging them to “take a fresh look at climate change.”
Their intent, apparently, was to disparage the views of scientists who disagree with their
contention that continued business-as-usual increases in carbon dioxide (CO2) emissions
produced from the burning of coal, gas, and oil will lead to a host of cataclysmic climate-
We, the undersigned, totally disagree with them and would like to take this opportunity to
briefly state our side of the story.
The eighteen climate alarmists (as we refer to them, not derogatorily, but simply because
they view themselves as “sounding the alarm” about so many things climatic) state that the
people of the world “need to prepare for massive flooding from the extreme storms of the
sort being experienced with increasing frequency,” as well as the “direct health impacts
from heat waves” and “climate-sensitive infectious diseases,” among a number of other
devastating phenomena. And they say that “no research results have produced any evidence
that challenges the overall scientific understanding of what is happening to our planet’s
climate,” which is understood to mean their view of what is happening to Earth’s climate.
To these statements, however, we take great exception. It is the eighteen climate alarmists
who appear to be unaware of “what is happening to our planet’s climate,” as well as the vast
amount of research that has produced that knowledge.
For example, a lengthy review of their claims and others that climate alarmists frequently
make can be found on the Web site of the Center for the Study of Carbon Dioxide and
Global Change (see http://www.co2science.org/education/reports/prudentpath/
prudentpath.php). That report offers a point-by-point rebuttal of all of the claims of the
“group of eighteen,” citing in every case peer-reviewed scientific research on the actual
effects of climate change during the past several decades.
If the “group of eighteen” pleads ignorance of this information due to its very recent
posting, then we call their attention to an even larger and more comprehensive report
published in 2009, Climate Change Reconsidered: The 2009 Report of the
Nongovernmental International Panel on Climate Change (NIPCC). That document has
been posted for more than a year in its entirety at www.nipccreport.org.
These are just two recent compilations of scientific research among many we could cite. Do
the 678 scientific studies referenced in the CO2 Science document, or the thousands of
studies cited in the NIPCC report, provide real-world evidence (as opposed to theoretical
climate model predictions) for global warming-induced increases in the worldwide number
and severity of floods? No. In the global number and severity of droughts? No. In the
number and severity of hurricanes and other storms? No.
Do they provide any real-world evidence of Earth’s seas inundating coastal lowlands around
the globe? No. Increased human mortality? No. Plant and animal extinctions? No. Declining
vegetative productivity? No. More frequent and deadly coral bleaching? No. Marine life
dissolving away in acidified oceans? No.
Quite to the contrary, in fact, these reports provide extensive empirical evidence that these
things are not happening. And in many of these areas, the referenced papers report finding
just the opposite response to global warming, i.e., biosphere-friendly effects of rising
temperatures and rising CO2 levels.
In light of the profusion of actual observations of the workings of the real world showing
little or no negative effects of the modest warming of the second half of the twentieth
century, and indeed growing evidence of positive effects, we find it incomprehensible that
the eighteen climate alarmists could suggest something so far removed from the truth as
their claim that no research results have produced any evidence that challenges their view of
what is happening to Earth’s climate and weather.
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But don’t take our word for it. Read the two reports yourselves. And then make up your
own minds about the matter. Don’t be intimidated by false claims of “scientific consensus”
or “overwhelming proof.” These are not scientific arguments and they are simply not true.
Like the eighteen climate alarmists, we urge you to take a fresh look at climate change. We
believe you will find that it is not the horrendous environmental threat they and others have
made it out to be, and that they have consistently exaggerated the negative effects of global
warming on the U.S. economy, national security, and public health, when such effects may
well be small to negligible.
Syun-Ichi Akasofu, University of Alaska1
Scott Armstrong, University of Pennsylvania
James Barrante, Southern Connecticut State University1
Richard Becherer, University of Rochester
John Boring, University of Virginia
Roger Cohen, American Physical Society Fellow
David Douglass, University of Rochester
Don Easterbrook, Western Washington University1
Robert Essenhigh, The Ohio State University1
Martin Fricke, Senior Fellow, American Physical Society
Lee Gerhard, University of Kansas1
Ulrich Gerlach, The Ohio State University
Laurence Gould, University of Hartford
Bill Gray, Colorado State University1
Will Happer, Princeton University2
Howard Hayden, University of Connecticut1
Craig Idso, Center for the Study of Carbon Dioxide and Global Change
Sherwood Idso, USDA, U.S. Water Conservation Laboratory1
Richard Keen, University of Colorado
Doral Kemper, USDA, Agricultural Research Service1
Hugh Kendrick, Office of Nuclear Reactor Programs, DOE1
Richard Lindzen, Massachusetts Institute of Technology2
Anthony Lupo, University of Missouri
Patrick Michaels, Cato Institute
Donald Nielsen, University of California, Davis1
Al Pekarek, St. Cloud State University
John Rhoads, Midwestern State University1
Nicola Scafetta, Duke University
Gary Sharp, Center for Climate/Ocean Resources Study
S. Fred Singer, University of Virginia1
Roy Spencer, University of Alabama
George Taylor, Past President, American Association of State Climatologists
Frank Tipler, Tulane University
Leonard Weinstein, National Institute of Aerospace Senior Research Fellow
Samuel Werner, University of Missouri1
Thomas Wolfram, University of Missouri1
1 – Emeritus or Retired
2 – Member of the National Academy of Sciences
Rodney Armstrong, Geophysicist
Edwin Berry, Certified Consulting Meteorologist
Joseph Bevelacqua, Bevelacqua Resources
Carmen Catanese, American Physical Society Member
Roy Clark, Ventura Photonics
John Coleman, Meteorologist KUSI TV
Darrell Connelly, Geophysicist
Joseph D’Aleo, Certified Consulting Meteorologist
Page of 71 152
Terry Donze, Geophysicist1
Mike Dubrasich, Western Institute for Study of the Environment
John Dunn, American Council on Science and Health of NYC
Dick Flygare, QEP Resources
Michael Fox, Nuclear industry/scientist
Gordon Fulks, Gordon Fulks and Associates
Ken Haapala, Science & Environmental Policy Project
Martin Hertzberg, Bureau of Mines1
Art Horn, Meteorologist
Keith Idso, Center for the Study of Carbon Dioxide and Global Change
Jay Lehr, The Heartland Institute
Robert Lerine, Industrial and Defense Research and Engineering1
Peter Link, Geologist
James Macdonald, Chief Meteorologist for the Travelers Weather Service1
Roger Matson, Society of Independent Professional Earth Scientists
Tony Pann, Meteorologist WBAL TV
Ned Rasor, Consulting Physicist
James Rogers, Geologist1
Norman Rogers, National Association of Scholars
Thomas Sheahen, Western Technology Incorporated
Andrew Spurlock, Starfire Engineering and Technologies, Inc.
Leighton Steward, PlantsNeedCO2.org
Soames Summerhays, Summerhays Films, Inc.
Charles Touhill, Consulting Environmental Engineer
David Wojick, Climatechangedebate.org
1 – Emeritus or Retired
February 10th, 2011 at 12:23 am
Global warming an excuse for government spending?
In response to a Wall Street Journal op-ed by Bjorn Lomborg, Scott Armstrong, Kesten Green, and
Willie Soon wrote the following letter questioning Lomborg’s poorly-justiﬁed advocacy.
“Let’s Deal in Science and Facts” – A letter to
the Wall Street Journal
Bjorn Lomborg (“Can Anything Serious Happen in Cancun?”, op-ed, Nov. 12) claims that
government spending on global warming policies is wasted, but he assumes that global
warming caused by carbon dioxide is a fact. It is not. We base this statement not on the
opinions of 31,000 American scientists who signed a public statement rejecting this
warming hypothesis (the “Oregon Petition”), but rather because the forecasts of global
warming were derived from faulty procedures.
We published a peer-reviewed paper showing that the forecasting procedures used by
the U.N.’s Intergovernmental Panel on Climate Change violated 72 of 89 relevant
principles (e.g., “provide full disclosure of methods”). The IPCC has been unable to
explain why it violated such principles. In response, we developed a model that follows
the principles. Because the climate is complex and poorly understood, our model
predicts that global average temperatures will not change.
In testing the models on global temperature data since 1850, we found that the long-
range (91-to-100-years ahead) forecast errors from the IPCC’s projection were 12 times
larger than the errors from our simple model.
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Mr. Lomborg concludes there are better ways for governments to spend the funds
devoted to global warming. We suggest this money should instead be returned to
J. Scott Armstrong, Kesten C. Green, Willie Soon.
See the letter on the!WSJ site!here.
February 7th, 2011 at 12:03 am
After 3 years of the climate bet, temperatures are back to the
After an excursion into cooler than average weather followed by an excursion into warmer than
average weather, three years into the ten-year climate bet temperatures are back to the 2007
average: the level predicted by Armstrong (see graph in right menu). Armstrong’s forecast was more
accurate than Gore’s for 20 of the 36 months to date, and two of the three years. The bet is decided
in favor of the forecast that delivers the smallest absolute error over the ten years or 120 months of
the bet. With 36 months gone, Gore’s total error so far is 6% smaller than Armstrong’s. With 84
months to go, the bet will continue to be interesting given that ten years is such a short period on
which to base a climate bet.
Note: We have had difﬁculty getting access to theclimatebet.com site to bring you updates over the
last few months, for which we apologize. We have now secured access and do not expect further
problems as we bring you updates on the bet each month, and occasional other news relevant to the
January 17th, 2011 at 4:41 am
Global Warming Alarm Based on Faulty Forecasting
Procedures: Comments on the United States Department of
State’s U.S. Climate Action Report 2010, 5th ed.
Submitted by J Scott Armstrong, Kesten C Green, and Willie Soon
Our research ﬁndings challenge the basic assumptions of the State Department’s Fifth U.S. Climate
Action Report (CAR 2010). The alarming forecasts of dangerous manmade global warming are not
the product of proper scientiﬁc evidence-based forecasting methods. Furthermore, there have been
no validation studies to support a belief that the forecasting procedures used were nevertheless
appropriate for the situation. As a consequence, alarming forecasts of global warming are merely
the opinions of some scientists and, for a situation as complicated and poorly understood as global
climate, such opinions are unlikely to be as accurate as forecasts that global temperatures will
remain much the same as they have been over recent years. Using proper forecasting procedures we
predict that the global warming alarm will prove false and that government actions in response to
the alarm will be shown to have been harmful.
Whether climate will change over the 21st Century, by how much, in what direction, to what effect,
and what if anything people could and should do about any changes are all forecasting problems.
Given that policy makers currently do not have access to scientiﬁc forecasts for any of these, the
policies that have been proposed with the avowed purpose of reducing dangerous manmade global
Page of 73 152
warming—such as are described in CAR 2010 Chapters 4, 5, 6, and 7—are likely to cause serious
and unnecessary harm.
In this comment on CAR 2010, we summarize ﬁndings from our research on forecasting climate.
Most of our ﬁndings have been published in the peer-reviewed literature and all have been
presented at scientiﬁc meetings. They are easily accessible on the Internet and we provide links to
(A pdf copy of the document, with links, is available here.)
May 5th, 2010 at 1:36 am
Gore loses the ﬁrst 2 years of the climate bet to Armstrong’s
What if Mr. Gore had accepted Professor Armstrong’s proposed ten-year bet on climate change in
2007? Gore!said that the temperature would go up while Armstrong predicted it would not change
from the 2007 average.!We assumed a relatively conservative prediction from Mr. Gore of a 0.03
degrees Centigrade increase per year:!the central projection of the U.N.’s Intergovernmental Panel
on Climate Change.
Over the years 2008 and 2009, Mr Gore’s forecast was closer than Professor Armstrong’s to the
actual monthly!temperature in only four of the 24 months.!Put another way Mr Gore’s forecast was
0.26 degrees too warm in 2008 and 0.08 degrees in 2009, whereas Professor Armstrong’s was 0.23
degrees too warm in 2008 and 0.02 degrees to warm in 2009.
We use the University of Alabama at Huntsville’s satellite measure of the global lower atmosphere
temperature!anomaly as our actual temperature in order to avoid the problems identiﬁed by
researchers and, more recently, the release of the “Climategate” emails, with the Hadley Centre
series used by the IPCC.
Professor Armstrong said that one must be cautious about small samples. The amount of variability
in annual!temperature is high relative to the predicted change, so Armstrong said that he expects to
lose in some years. As!shown by a 150-year simulation of the bet, he said that he had only a bit
better than 50% chance of winning a!given year, but this jumps to nearly 70% for ten years.
Armstrong said, “it is about as certain as one can be in!forecasting that I would win if the bet were
for 100 years, but I wanted to see what would happen, so I proposed!only ten years.”
January 31st, 2010 at 10:54 am
History shows manmade global warming alarm to be false –
but that harmful policies will persist
Using a forecasting method that they have developed, Dr. J. Scott Armstrong from the Wharton
School and Dr. Kesten C. Green from the International Graduate School of Business at the
University of South Australia conclude that alarm over “dangerous manmade global warming” is
the latest example of a common social phenomenon involving alarming but unscientiﬁc forecasts
that prove to be wrong. This is a preliminary ﬁnding from the “global warming analogies
forecasting project.” The researchers stressed that the ﬁndings are preliminary because they are still
collecting and coding information on similar situations from the past.
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Armstrong and Green used a method known as “structured analogies.” For the global warming
analogies forecasting project, the method ﬁrst involved conducting a wide and objective search for
situations similar to the alarm over forecasts of dangerous manmade global warming. For each
analogous situation the forecasting procedures used by the alarmists and the actual outcomes of the
situations were coded. The structured analogies procedures had previously been shown to provide
excellent forecasts compared to those from commonly used alternative procedures.
To date, 71 situations have been proposed and 26 of them were found to meet all criteria of
similarity. Of the latter, none were based on forecasts from scientiﬁc procedures. Instead they were
based on dramatic speculation of one sort or another.
Typically, the alarmists recommend government action, and governments usually respond. They did
so in 25 of the 26 analogous situations, and government took action in 23.
We asked: How many of the 26 analogous alarming forecasts were accurate?
The answer is “none”.
In how many of the 23 analogies were the government solutions shown to be helpful?
None. In fact, in 20 situations there was substantial long-term harm from the government solutions.
The authors are hopeful that the continuing evidence on the anti-scientiﬁc procedures used by
people involved in the manmade global warming alarmist movement, such as has been exposed by
ClimateGate, will help to reduce the damage from the alarm in the long run. However, the analogies
offered little hope on that score. Most of the previous alarms, such as over DDT and
electromagnetic ﬁelds, continued to cause substantial harm many years after they had been shown
to be false.
Julian Simon and others had suggested that such a pattern exists for forecasts of doom, but we were
surprised at the strength of our ﬁndings. In retrospect, the ﬁndings seem less surprising. Extreme
events are difﬁcult to forecast, especially in complex and uncertain situations. So the application of
unscientiﬁc forecasting procedures supported by politics would be unlikely to produce useful
The authors stress that this is an early progress report. They hope to stimulate global warming
alarmists to propose analogies that support their forecasts. They also suggest that all important
public policy forecasts would beneﬁt by using the structured analogies method.
For the latest summary of this research, go to their paper, “Effects of the Global Warming Alarm.”
For further information, contact Armstrong@wharton.upenn.edu or email@example.com
December 12th, 2009 at 7:10 am
Forecasting experts’ simple model leaves expensive climate
A simple model was found to produce forecasts that are over seven times more accurate than
forecasts from the procedures used by the United Nations Intergovernmental Panel on Climate
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This important ﬁnding is reported in an article titled “Validity of climate change forecasting for
public policy decision making” in the latest issue of the International Journal of Forecasting. It is
the result of collaboration among forecasters J. Scott Armstrong of the Wharton School, Kesten C.
Green of the University of South Australia, and climate scientist Willie Soon of the Harvard-
Smithsonian Center for Astrophysics.
In an earlier paper, Armstrong and Green found that the IPCC’s approach to forecasting climate violated 72
principles of forecasting. To put this in context, would you put your children on a trans-Atlantic flight if you
knew that the plane had failed engineering checks for 72 out of 127 relevant items on the checklist?
The IPCC violations of forecasting principles were partly due to their use of models that were too complex
for the situation. Contrary to everyday thinking, complex models provide forecasts that are less accurate
than forecasts from simple models when the situation is complex and uncertain.
Confident that a forecasting model that followed scientific forecasting principles would provide more
accurate forecasts than those provided by the IPCC, Green, Armstrong and Soon used a model that was
more consistent with forecasting principles and knowledge about climate.
The forecasting model was the so-called “naïve” model. It assumes things will remain the same. Being such
a simple model, people are generally not aware of its power. In contrast to the IPCC’s central forecast that
global mean temperatures will rise by 3˚C over a century, the naïve model simply forecasts that
temperatures next year, the year after, and so on for each of 100 years into the future would remain the same
as the temperature in the year prior to the start of the forecasting exercise. Picture a graph of temperature
over time: the naïve forecasts would appear as a flat line.
The naïve model approach is confusing to non-forecasters who are aware that temperatures have always
varied. Moreover, much has been made of the observation that the temperature series that the IPCC uses
shows a broadly upward trend since 1850 and that this coincides with increasing industrialization and
associated increases in manmade carbon dioxide gas emissions.
To t es t th e na iv e mo de l, w e st ar ted w it h th e ac tu al g lo ba l av er ag e te mp era tu re f or t he y ea r 18 50 a nd
simulated making annual forecasts from one to 100 years after that date – i.e. for every year from 1851 to
1950. We t hen st ar t ed wi th th e a c tu al 18 5 1 te m pe r at ur e a nd m ad e s im u la te d f o re ca s ts fo r e ac h o f t he ne x t
100 years after that date - i.e. for every year from 1852 to 1951. This process was repeated over and over
starting with the actual temperature in each subsequent year, up to 2007, and simulating forecasts for the
years that followed (i.e. 100 years of forecasts for each series until after 1908 when the number of years in
the temperature record started to diminish as we approached the present). This produced 10,750 annual
temperature forecasts for all time horizons, one to 100 years, which we then compared with forecasts for the
same periods from the IPCC forecasting procedures. It was the first time that the IPCC’s forecasting
procedures had been subject to a large-scale test of the accuracy of their forecasts.
Over all the forecasts, the IPCC error was 7.7 times larger than the error from the naïve model.
While the superiority of the naïve model was modest for one to ten-year-ahead forecasts (where the IPCC
error was 1.5 times larger), its superiority was enormous for the 91- to 100-year-ahead forecasts, where the
IPCC error was 12.6 times larger.
Is it proper to conduct validation tests?
In many cases, such as the climate change situation, people claim that: “Things have changed! We cannot
use the past to forecast.” While they may think that their situation is unique, there is no logic to this
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argument. The only way to forecast the future is by learning from the past. In fact, those who are
proclaiming the dangers of global warming also base their assumptions on their analyses of the past.
Could one improve upon the naïve model? While the naïve model is much more consistent with forecasting
principles the IPCC’s approach to forecasting climate, it does violates some principles. For example, the
naïve model violates the principle that one should use as long a time series as possible, because it bases all
forecasts on simply the global average temperature for the single year just prior to making the forecasts. It
also fails to combine forecasts from different reasonable methods. The authors planned to start simple with
this self-funded project and to then obtain funding to undertake a more ambitious forecasting effort to ensure
that all principles were followed. This would no doubt improve accuracy. However, the forecasts from the
naïve model were very accurate. For example, the mean absolute error for the 108 fifty-year-ahead forecasts
was only 0.24˚C. It is difficult to see any economic value to reducing such a small forecast error.
We concluded our most recent paper with the following thoughts:
Global mean temperatures have been remarkably stable over policy-relevant horizons. The
benchmark forecast is that the global mean temperature for each year for the rest of this century
will be within 0.5C of the 2008 ﬁgure.
There is little room for improving the accuracy of forecasts from our benchmark model. In fact,
it is questionable whether practical beneﬁts could be gained by obtaining perfect forecasts. While
the Hadley temperature data relied upon by the IPCC drifts upwards over the last century or so,
the longer series shows that such trends can occur naturally over long periods before reversing.
Moreover, there is concern that the upward trend observed over the last century and half might
be at least in part an artefact of measurement errors rather than a genuine global warming.
Even if one accepts the Hadley data as a fair representation of temperature history (and that is
debatable, especially given the recent revelations about possible irregularities in temperature data
handling by the Climate Research Unit at the University of East Anglia), our analysis shows that
errors from the naive model would have been so small that decision makers who had assumed
that temperatures would not change would have had no reason for regret.
For further information contact J. Scott Armstrong (http://jscottarmstrong.com or Kesten C. Green (http://
December 6th, 2009 at 10:43 am
Our View on the “ClimateGate” scandal: Why didn’t the
mainstream media expose it years ago?
Climategate is the opening up of a world that has been well known to scientists who are skeptical
about the claim that we are faced with dangerous manmade global warming.
That world includes fudged data, refusal to disclose data and methods, removing evidence that
challenges global warming dogma from Wikipedia entries, failure to cite disconﬁrming evidence in
papers and IPCC reports, drawing conclusions that go beyond the data, violations of proper
scientiﬁc procedures in collecting and analyzing data, ad hominem arguments, promulgation of
alarming but unsupported forecasts, failure to correct errors that have been pointed out in the
literature, uncivil behavior, disrupting scientiﬁc talks with protestors, directing government funds to
those who subscribe to the dogma, providing government funds for research studies designed to
Page of 77 152
support the dogma, putting out false or misleading “ﬁndings,” cancelling stories that had been
scheduled for publication in newspapers, ﬁring skeptics, death threats, and so on.
These are the signs of a dangerous political movement, not of a scientiﬁc issue.
Skeptical scientist have been telling editors in the popular media about the scandal of government
sponsored climate science for years. Why have they been so reluctant to expose the scandal?
Other opinions on ClimateGate, some which seem sensible and others strange to us as scientists, are
available from the New York Times, Glenn Beck, the Wall Street Journal, the London Telegraph.
November 28th, 2009 at 2:10 am
Monckton’s fresh challenge: Al, either debate climate or keep
your opinions to yourself
Lord Monckton, science advisor to British Prime Minister Margaret Thatcher, issued a fresh
challenge to Al Gore on the Glenn Beck show. Monckton urged Gore to take the opportunity to
publicize the issue of “manmade global warming” on international television. Raising the heat
further, Monckton suggested that if Gore was not prepared to debate the issue, he should refrain
from further public comment. The think tank CEI, are supporting Monckton’s call by offering “big
bucks” to Gore if he will make himself available for a debate. See the video of Monckton’s call and
CEI’s offer and CEI’s media release.
November 17th, 2009 at 4:02 am
Al Gore’s forecasts perform poorly compared to assuming
temperatures won’t change
Some things are hard to forecast. In such cases forecasters ﬁnd it hard to beat a simple prediction
that things will not change. When Kesten Green, Scott Armstrong, and Willie Soon tested the
forecast of global average temperatures apparently preferred by Al Gore (the IPCC’s +0.03C per
year scenario) for the years of exponential CO2 emissions growth from 1851 to 1975, they found
the IPCC “forecast” errors were more than seven times bigger than the no-change benchmark
errors. The ﬁnal draft of their International Journal of Forecasting paper is available, here.
October 25th, 2009 at 8:41 pm
Will unscientiﬁc climate forecasts lead to a powerful and
unelected World Government?
Lord Christopher Monckton read the proposed Copenhagen agreement and concluded that, unless
U.S. citizens are able to pressure their government to not sign the agreement at the December 2009
summit, unelected world government and large transfers of wealth from developed countries to
undeveloped ones will result. Listen to the rousing conclusion to his 14 October speech here.
October 22nd, 2009 at 10:34 pm
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Climate science made easy: Please include this child’s lesson
on the urban heat island effect in your next movie, Mr. Gore
Here is evidence from a child’s science project that increased temperatures in the U.S. over the 20th
Century can be attributed to the urban heat island effect, and not “global warming”. (Large cities
cover only a tiny fraction of the area of the Earth.) I urge others to independently replicate and
extend this school boy’s experiment and to report the results. The ﬁndings of the study also provide
a solution for those who remain concerned about warming: Abandon the cities!
For an earlier discussion of this issue, see Steve McIntyre’s 2007 essay “Trends in Peterson 2003”.
October 12th, 2009 at 9:43 pm
Results to September ’09: A warm month but no cigar for
The September global mean temperature anomaly was +0.42C, a relatively warm month as the
updated results graph in the right column shows. Armstrong was a clear winner for the 2008 year;
with nine months of 2009 gone, what are the prospects of Gore winning 2009? With the average
temperature anomaly for the year-to-date at +0.23C clearly below both Armstrong’s and Gore’s
year-to-date forecasts of +0.28C and +0.33C respectively, Armstrong is looking good to win 2009.
For Gore to win 2009 now, the average temperature anomaly for the remaining three months of
2009 would have to equal or exceed +0.535C. This has happened on only two previous occasions in
the last 31 years, February to April and May to July 1998, during the warmest part of a strong El
October 10th, 2009 at 2:18 am
Results so far: Gore has lost 18 of the ﬁrst 20 months of “the
Result for the ﬁrst 20 months of the bet, to the end of August 2009, are shown in the graph below
the globe image on the top right of this page. Gore has now lost 18 of the 20 months since the “bet”
At the time of writing, the HubDub prediction market gives Armstrong a 73% chance of winning
September 21st, 2009 at 10:58 pm
TheClimateBet Tracker: Assume Mr. Gore took the bet
Theclimatebet.com will report monthly results on the climatebet, assuming that Mr. Gore took the
bet. Professor Armstrong says it is all part to natural variation that occurs over time. He expects the
scientiﬁc approach to forecasting will win in the long-run, so the longer the horizon, the greater the
chance for Prof. Armstrong to win. Based on simulations of changes over the past 157 years, his
chances of winning would be in excess of 62% for the ten-year horizon of the bet. On a monthly
basis, he expects it to be slightly in excess of 50%. Mr. Gore believe that we cannot afford to wait
Page of 79 152
because global warming is happening rapidly. Thus, he should ﬁnd this monthly tracking to be of
great interest. For purposes of the bet we assumed that Mr. Gore agreed with the IPCC forecast of
30C rise per century whereas Professor Armstrong forecast no change.
September 13th, 2009 at 9:04 pm
Climate Change Reconsidered: The Report of the
Nongovernmental International Panel on Climate Change
While theclimatet.com focuses on forecasting issues, the forecasts are, of course, affected by the
knowledge about causal factors. To date, this literature has been scattered over a wide number of
disciplines and a staggering number of journals. Thankfully, a convenient source for the scientiﬁc
evidence has recently been published: Climate Change Reconsidered: The Report of the
Nongovernmental International Panel on Climate Change. In contrast to the IPCC report by the
United Nations, there were no political pressures involved in this report – and much of the research
was done without funding. You can see many reviews at amazon.com – nearly all highly favorable
at present — and much discussion of this book on blogs.
August 20th, 2009 at 11:16 pm
Paper presented at the ISF 2009 in Hong Kong on
"Forecasting for climate policy: C02, global temperatures, and
Scott Armstrong presented a paper co-authored with Kesten Green, Andreas Graefe, and Willie
Soon at the International Symposium on Forecasting in June that examined some of the lessons for
climate policy from evidence-based forecasting. The authors described the lack of scientiﬁc long-
term forecasts of global temperatures, the impacts of temperature changes, and the effects of
policies. The paper explained the need for simple methods and conservative forecasts in the face of
uncertainty and complexity and pointed out that simple no-change benchmark forecasts are
sufﬁciently accurate for policy decisions. In contrast, simple causal models with CO2 as the policy
variable are not credible.
Prediction markets for temperatures in three and ten years time agree that the no-change forecast is
the more likely outcome than the IPCC 0.03C per annum forecast. Finally, similar (analogous)
alarms in the past identiﬁed by the authors and others turned out to be false alarms. The slides for
the talk are available here.
Written by mzfeldm
July 19th, 2009 at 4:18 pm
UK Lawyer Slams Gore Over Court Case Claims
Written by Ann McElhinney & Phelim McAleer
As appeared on The Climate Depot and elsewhere.
A leading UK lawyer, who represented the parent that sued Al Gore in the British High
Court, has laughed off claims by the former vice-president that the judge ruled in his favour.
Page of 80 152
Speaking from London John Day, a senior partner in Malletts Solicitors, said Mr Gore was
misrepresenting what the judge had found. Mr Day represented a British parent who sued
the UK Ministry of Education when they wanted to distribute and show Mr Gore’s
documentary An Inconvenient Truth to every British school child. In the 2006 documentary
Mr Gore claimed humanity is in danger because of man made Global Warming. He also
claimed ﬂooding and disease would increase with the destruction of most of the world’s
major cities including New York, London and Shanghai. As a result Mr Gore was awarded a
Nobel Peace Prize and the documentary won an Oscar.
However, after a lengthy hearing a High Court Judge, Mr Justice Burton, found that An
Inconvenient Truth contained signiﬁcant scientiﬁc errors in nine key areas . But questioned
about the embarrassing High Court decision during a current trip to Australia Mr Gore stated
on ABC Australia “Well, the ruling was in my favour.”! However, this has been rejected by
Mr Day who said Mr Gore’s latest claims are “difﬁcult to square with the reality of the
judgement”. “The judge found there were nine serious scientiﬁc errors in the ﬁlm.” He said
the court ordered that the ﬁlm was “not suitable to be shown in British schools without a
health warning”. “Mr Justice Burton said an Inconvenient Truth wasn’t ﬁt to be shown in
British schools without suitably corrected guidance which drew attention to the errors in the
ﬁlm and its political partisanship.” Among the errors listed by Mr Justice Burton were Mr
Gore claims that rising sea levels would destroy cities in the near future, that the polar bear
was endangered and that the snows of Kilimanjaro were melting all because of Global
Warming. The judge found these to be scientiﬁc errors. He also dismissed Mr Gore’s claims
that Hurricane Katrina was caused by Global Warming.
July 19th, 2009 at 1:13 pm
Climate forecasting at the ISF in Hong Kong: A warm-up quiz
Is carbon dioxide a good causal variable for forecasting global temperature? Have there been alarms
in the past similar to the current alarm over dangerous manmade global warming and, if so, what
happened? Can rule-based forecasting help forecast global mean temperatures? What do prediction
These questions and more will be answered at a climate forecasting session at the International
Symposium on Forecasting presenting work by Green, Armstrong, and Graefe. To be useful,
forecasts should be substantially more accurate than those from a simple benchmark method, for
example the no-change model. We suggest taking the following self-administered quiz Please write
down your estimate and then follow the link to ﬁnd the answer.
Q. Assume that at the end of 1850 you started making 50-year-ahead no-change forecasts such that
your ﬁrst forecast was that the global mean temperature in 1900 would be the same as 1850’s. By
2008 you would have accumulated 108 forecasts for which you knew the global mean temperature
(i.e to 2007). What would be the mean absolute error of your 50-year ahead no-change forecasts in
A. See the abstract of the Green, Armstrong, and Soon International Journal of Forecasting paper
“Validity of Climate Change Forecasting for Public Policy Decision Making.”
Written by mzfeldm
June 4th, 2009 at 3:06 pm
Page of 81 152
New Prediction Market Released for the Climate Bet
The climate bet between Scott Armstrong and Al Gore was released in a real money prediction
market on Intrade. Gore predicts that it will be warmer, while Armstrong predicts no change. Who
will be ahead after three years? Monitor the current status and place your bets here.
Written by mzfeldm
May 21st, 2009 at 10:57 am
A lighter note: One view of Al Gores's approach to global
Take a beak from the serious discussions on the topic to view this spoof of Al Gore, which appeared
recently on liberalmadness.com
Written by mzfeldm
May 16th, 2009 at 10:09 pm
Gallup Poll Editor describes Al Gore's losses in the global
As published on The Climate Depot,! Gallup Poll Editor Frank Newport commented on Al Gore’s
validity in the global warming debate.
“Any measure that we look at shows Al Gore’s losing at the moment. The public is just not that
Written by mzfeldm
May 7th, 2009 at 8:11 pm
Gore dodges questioning from global warming skeptic Lord
Gore avoids appearing with Lord Moncton at scheduled hearing by the U.S. House Energy and
Commerce meeting on April 24. ‘House Democrats don’t want Gore humiliated’ according to the
Climate Depot on Thursday. April 23, 2009.
Washington DC — UK’s Lord Christopher Monckton, a former science advisor to Prime Minister
Margaret Thatcher, claimed House Democrats have refused to allow him to appear alongside former
Vice President Al Gore at high proﬁle global warming hearing on Friday April 24, 2009 at 10am in
Washington. Monckton told Climate Depot that the Democrats rescinded his scheduled joint
appearance at the House Energy and Commerce hearing on Friday. Monckton said he was informed
that he would not be allowed to testify alongside Gore when his plane landed from England
Thursday afternoon. More…
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Written by mzfeldm
April 26th, 2009 at 11:08 am
Scott Armstrong featured in “The Unwisdom of Solomon”
Does the Wisdom of Solomon Extend to the Science of
by J. Scott Armstrong
SOLOMON ET AL. (2009) share their opinions with us about what will happen to the
climate over the next 1,000 years. I am willing to accept that Susan Solomon and her
coauthors are experts in their ﬁelds and that they are doing their best to provide useful long-
term forecasts. For the purposes of discussion, let’s assume that they are the smartest people
in the world and that, like King Solomon, they have great wisdom. But are their forecasts of
any value? Evidence on the value of experts’ forecasts began to be published in the 1930s. I
summarized the evidence in Armstrong (1978). When I found that people resisted the
evidence, I proposed the seer-sucker theory: “No matter how much evidence exists that seers
do not exist, seers will ﬁnd suckers” (Armstrong 1980).
And then, along came Philip Tetlock (2005) with ﬁndings from an ambitious experiment. He
had recruited 284 people whose professions included “commenting or offering advice on
political and economic trends.” He asked them to forecast the probability that various
outcomes would or would not occur, picking situations within and outside their areas of
expertise. Over a 20-year period ending in 2003, he had accumulated 82,361 forecasts. He
then evaluated the experts’ predictions against the outcomes, and compared these with
predictions from simple statistical procedures, uninformed non-experts, and well-informed
non-experts. The experts barely if at all outperformed informed non-experts and neither
group of forecasters did well against simple rules and models. What can we conclude about
the value of predictions from experts who are unaided by scientiﬁc forecasting principles?
Here is how we summarized the ﬁndings in Green and Armstrong (2007).
For long-term forecasts for complex situations where the causal factors are subject to
uncertainty (as with climate), unaided judgmental forecasts by experts have no value. This
applies whether the opinions are expressed in words, spreadsheets, or mathematical models.
It applies regardless of how much scientiﬁc evidence [about the domain of interest] is
possessed by the experts. Among the reasons are:
a) Complexity — People cannot assess complex relationships through unaided
b) Coincidence — People confuse correlation with causation.
c) Feedback — People making judgmental predictions rarely receive unambiguous
feedback they can use to improve their forecasting.
d) Bias — People have difﬁculty obtaining or using evidence that contradicts their initial
beliefs. People who view themselves as experts are particularly prone to this problem.
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In sum, speculation about the future, even by the cleverest and most well-informed people,
should be spurned by policymakers. Instead, policymakers should make decisions based
upon forecasts from scientiﬁc forecasting procedures.
Armstrong, J.S. (1980). “The seer-sucker theory: The value of experts in forecasting,”
Technology Review, 83 (June-July), 16-24.
Armstrong, J.S. (1978). Long-Range Forecasting: From Crystal Ball to Computer. New
Green, K. C. & J. S. Armstrong (2007). “Global warming: Forecasts by scientists versus
scientiﬁc forecasts,” Energy and Environment, 18, 997-1021.
Solomon, S., G. Plattner, R. Knutti & P. Friedlingstein (2009). “Irreversible climate
changes due to carbon dioxide emissions,” Proceedings of the National Academy of
Sciences, Feb 10, 2009.
Tetlock, P.E. (2005). Expert Political Judgment: How Good Is It? How Can We Know?
Princeton, NJ: Princeton University Press.
April 6th, 2009 at 1:02 pm
International Climate Change Conference (ICCC) 2009 talks
Talks (videos, audios, and PowerPoint shows) have been posted for all of the talks given at the
International Climate Change Conference in New York City in early March of 2009. Judge for
yourself as to the quality of the scientiﬁc work presented. The talks are here.
Written by mzfeldm
March 30th, 2009 at 8:33 pm
Scott Armstrong interviewed by BBC
Scott Armstrong was interviewed about the polar bear “crisis” by BBC on March 9. Here is the 6-
Written by mzfeldm
March 16th, 2009 at 9:00 pm
Is the World Wildlife Fund Polar Bear Campaign Based on
The World Wildlife Fund (WWF) has been running commercials to appeal for members and
donations. The commercials have claimed that global warming is causing the population of polar
bears to decrease rapidly thereby putting the species at risk of extinction. Might the WWF be
engaged in false advertising? This the question that Scott Armstrong, a professor of marketing at the
Wharton School who has taught advertising for over 35 years, is asking. Professor Armstrong will
discuss this case at the International Conference on Climate Change on March 9 in New York City.
Page of 84 152
He has been trying to contact senior ofﬁcers of the WWF since December 12, 2008, to ask them to
explain their side of the story. Despite many attempts, he has not received a response from the
WWF. See a full description of the problem and prior correspondence below.
In an appeal for members and donations, commercials by the World Wildlife Fund (WWF) have
claimed that the number of polar bears is decreasing rapidly, thereby putting the entire species at
risk of extinction. For example, here are excerpts from a TV commercial, “Noah Wyle for the
WWF,” posted on YouTube and stating that because of climate change:
“Polar bears are on their way to extinction. If we don’t act now, most will die in our
children’s lifetime. But you can help change that. Call now and join the Wildlife Rescue
team. . . . If we don’t act now, it could be too late for the polar bear.”
Professor Scott Armstrong, a Wharton School professor wondered what the basis was for these
claims. The statement that “polar bears are on their way to extinction” is at odds with the conclusion
of his recently published paper which showed that there were no scientiﬁc forecasts to support such
a claim (Armstrong, Green & Soon, “Polar Bear Population Forecasts: A Public-Policy
Forecasting Audit,” Interfaces (2008), 38, 382–405).
As was discussed at the Hearings by the Senate Committee on Environment and Public Works on
January 30, 2008, there are apparently many more polar bears now than there were a few decades
ago because the ban on hunting has been so successful in protecting them.
Interestingly, as of February 2009, the WWF website claims that:
“The general status of polar bears is currently stable, though there are differences between
the populations. Some are stable, some seem to be increasing, and some are decreasing
due to various pressures. The status of several populations is not well documented.” This
statement contradicts the claim in their advertising campaign.”
Do the WWF commercials represent a case of false advertising, that is, of soliciting money under
false premises? If so, should the WWF be required to return the donations that might have
conceivably been raised from this campaign? What actions might be taken? Is it a case for federal
Professor Armstrong has been attempting to contact the WWF’s President and CEO and seven of its
trustees by mail, phone, and e-mail since December 12, 2008. Armstrong recommended that the
campaign be stopped and that corrective ads should be run to offer to return donations and
membership fees. He also mentioned that he would discuss this case in his talk at the International
Conference on Climate Change in New York City on March the 8th to 10th and, to be fair, he would
like to present the WWF’s side of the story. To that end, Armstrong said he would circulate a WWF
response at his talk. The correspondence for this case is posted at theclimeatebet.com.
As of February 25, he had not received a response from the WWF.
Reference: Armstrong, J.S., K. C. Green and W. Soon “Polar Bear Population Forecasts: A Public-
Policy Forecasting Audit,” with commentary, Interfaces (2008), 38, No. 5, 382–405
Contact: For further information, contact Professor J. Scott Armstrong at
Mr. Bruce Babbitt, Chairman of the Board February 17, 2009
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World Wildlife Fund
1250 Twenty-Fourth Street, N.W.
P.O. Box 97180
Washington, DC 20090-7180
Dear Mr. Babbitt,
I have been trying to contact representatives of the World Wildlife Fund, but so far,
I have not had much luck. Might you be able to respond to my concerns? I attach a
record of my previous correspondence.
Thanks you for your help in this matter.
J. Scott Armstrong
Professor of Marketing, The Wharton School, U. of PA.. Phila., PA 19104
Home address: 645 Harper Ave., Drexel Hill, PA 19026
Fax 215-898 2534
To the Trustees of the World Wildlife Fund
February 14, 2009
I sent the letter copied below to the President and CEO of the WWF, Mr.
Carter Roberts, on December 12, 2008 via U.S. mail. I sent a follow-up letter
on January 13, 2009, followed by a fax on January 27. I have received no
reply to my correspondence and my attempts to obtain an email address or
phone number for him have been fruitless.
I have checked the WWF website and found it difﬁcult to obtain contact
information for many of the key people. The six Trustees to whom I have
addressed this message were the only ones whose email addresses I could
My letter to Mr. Roberts concerns the important issue of misleading
advertising by the WWF, a subject with which I am familiar having taught
advertising at the Wharton School for about 38 years. I would be grateful if
you would acknowledge receipt of this email and respond to my original
letter to Mr. Roberts.
I plan to discuss this issue in my talk at the upcoming 2009 International
Conference on Climate Change in New York City on March 8 to 10. In the
interests of fairness, the WWF’s side of the issue should be presented. If
you like, I will make an enquiry as to whether it would be possible for a
representative of the WWF to attend the conference and give a short reply
from the ﬂoor.
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J. Scott Armstrong
Professor of Marketing, The Wharton School, U. of PA.. Phila., PA 19104
Home address: 645 Harper Ave., Drexel Hill, PA 19026
Fax 215-898 2534
On January 27, 2009, I sent a fax to Mr. Roberts that followed up on the letter of January 13 and
included the material below.
On January 13, 2009, I resent the letter to Mr. Roberts with the following note at the beginning:
“On December 12, 2008, I sent the following letter to you by U.S Postal service, but to date,
I have not received a response. !Perhaps you did not receive the letter?
I look forward to hearing from you.”
Mr. Carter Roberts !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!December 12, 2008
President and CEO
World Wildlife Fund
1250 Twenty Fourth Street N.W.
Washington, D.C. 20090-7180
Dear Mr. Roberts,
On November 9th, 2008, I watched a World Wildlife Fund TV commercial in which I
believe you were the spokesperson, but essentially the same video has also aired with Noah
Wyle and Sharon Lawrence as spokespersons. !In an appeal for members and donations, the
advertisement provides a message that the number of polar bears is decreasing rapidly,
thereby putting the entire species at risk of extinction.
The claim is surprising because the following statement was on the WWF website at http://
polar_bear/pbear_population_distribution/index.cfm on November 14, 2008:
“The general status of polar bears is currently stable, though there are differences between
the populations. Some are stable, some seem to be increasing, and some are decreasing due
to various pressures. The status of several populations is not well documented.”
With my colleagues, Drs. Kesten Green and Willie Soon, I have reviewed the U.S.
Department of the Interior reports on the polar bear population, and they do not provide
scientiﬁc support for the claims made in your organization’s advertisement. We were unable
to obtain evidence indicating a decline in the polar bear population.
Based on relevant published information, we found that the polar bear population has in fact
been increasing since hunting restrictions were imposed in the 1970s. These ﬁndings were
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commonly accepted in the U.S. Senate Committee on Environment and Public Works
hearing on January 30, 2008. Attached is a copy of my testimony for your examination. !In
addition, I invite you to read our subsequent paper that also addresses this issue:
Armstrong, J. S., Green, K. C., & Soon, W. (2008), “Polar Bear Population Forecasts: A
Public-Policy Forecasting Audit,” Interfaces, 38, 382-345.
As I am sure you are aware, it is important for advertisers to avoid making false claims. I
suggest that you withdraw your inaccurate advertisements and run corrective ads that offer
to return donations and membership fees.
I look forward to hearing from you on this matter.
J. Scott Armstrong
Professor of Marketing, The Wharton School, U. of PA.. Phila., PA 19104
Home address: 645 Harper Ave., Drexel Hill, PA 19026
Fax 215-898 2534
Attached: Professor Armstrong’s Testimony Submitted to the Senate Committee on
Environment and Public Works (Written version) on January 30, 2008
March 2nd, 2009 at 9:19 am
Who would win the ‘Climate Bet’, Al Gore or Scott
In his talk on March 9, 2009 at the International Climate Change Conference in New York City,
Wharton Professor J. Scott Armstrong will announce the launch of a prediction market on the
outcome of the „Climate Bet‟ he proposed to Mr. Gore in 2007. Prediction markets are a structured
scientiﬁc approach to eliciting and summarizing peoples‟ opinions. The Climate Bet prediction
market is part of a project led by Andreas Graefe, a researcher at the Karlsruhe Institute of
Technology (KIT) in Germany, to examine the use of prediction markets for controversial public
policy issues. Are prediction markets useful in aiding the democratic process?
Prediction Markets for Public Policy – The Controversial Termination of the PAM
Prediction markets can lead to controversy when applied to public policy. For example, the goal of
the Policy Analysis Market (PAM), sponsored by the DARPA (Defense Advanced Research Projects
Agency) from 2001 to 2003, was to improve intelligence analysis by predicting military and
political instability around the world. Shortly before the scheduled start of PAM September 2003,
two Democratic Senators held a press conference accusing the U.S. Department of Defense of
planning a “terror market” for people to bet on terrorist events. The topic drew media attention;
over the following two days, 128 media articles were published. Most of the articles cast PAM in an
unfavorable light. PAM was rapidly terminated. Later, Robin Hanson, who had been involved in the
project, conducted a statistical analysis on more than 600 media articles that mentioned PAM. He
found that more informed articles favored PAM. Despite this, the political decision to dismiss PAM
was made and the chance to analyze the use of prediction markets for public policy was missed.
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Another Attempt – The Climate Bet Prediction Market
Mr. Gore has claimed that there are scientiﬁc forecasts that the Earth will become warmer and that
this will occur rapidly. Dr. Armstrong, along with Dr. Kesten Green, examined this claim and found
forecasts by some scientists, but no scientiﬁc forecasts. As a result, in June 2007, Dr. Armstrong
offered Mr. Gore a bet of $10,000 on who could best forecast annual mean temperatures over the
next ten years. The funds were to be put in a trust at the end of 2007, to be distributed to a charity
ten years later.
The goal of this bet was to promote the proper use of science in formulating public policy. This
involves such things as full disclosure of forecasting methods and data, and the proper testing of
alternative methods. Mr. Gore declined the bet, claiming that he does not bet money. Here is how
the prediction market bet is currently framed: “Now, assume that Armstrong and Gore made a
gentleman‟s bet (no money) and that the ten years of the bet started on January 1, 2008.
Armstrong‟s forecast was that there would be no change in global mean temperature over the next
ten years. Gore did not specify a method or a forecast. Nor did searches of his book or the Internet
reveal any quantitative forecasts or any methodology that he relied on. He did, however, imply that
the global mean temperature would increase at a rapid rate – presumably at least as great as the
IPCC‟s 1992 projection of 0.03°C-per-year. Thus, the IPCC‟s 1992 projection is used as Gore‟s
forecast.” Mr. Gore has been invited to comment on this effort as the plan is to extend it to other
betting sites. Dr. Armstrong has offered to distribute Mr. Gore‟s comments during his talk at the
International Climate Change Conference.
In preparation for the upcoming conference, the bet has been posted on hubdub.com, a play-money
market accessible at http://tinyurl.com/gore-armstrong-bet. Anyone can participate. For further
information, contact Andreas Graefe, who is currently a visiting scholar at the Wharton School.
700 Jon M. Huntsman Hall 3730 Walnut Street University of Pennsylvania Philadelphia , PA 19104
February 23, 2009
February 23rd, 2009 at 11:24 pm
Test Your Climate Change IQ
Take this one-question quiz and see how well you can forecast global average temperatures.
Assume that at the end of 1850 you forecast that the global average temperature in 50 years (the
year 1900) would be the same as the 1850 average. Every year after that, you repeated the process.
For example, at the end of 1851, you forecast that the global average temperature in 1901 would be
the same as the 1851 average.
By now you have accumulated 108 ﬁfty-year-ahead forecasts. Assume that you compared each of
the 108 forecasts with the actual global average temperature as measured by the U.K. Met Ofﬁce’s
Hadley Centre in order to calculate your errors.
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