The Decadal Global Climate Bet

This page provides an up to date view of the Global Decadal Climate Bet.

Details of The Bet are available at NoTricksZone here.

Update at 6 years and 7 months: July 2017 (month 79/120)

Worksheet with data available here.


Update at 6 years and 6 months: June 2017 (month 78/120)

This update includes updated data from RSS to version 4.  Clearly the warming team are now further in the lead.

I think it’s highly likely the warming team will win the bet … unless a major La Nina turns down the thermostat several notches, or a huge volcano blows it’s top.

If you’re interested I have stored the Excel worksheet here.

Update at 6 years 5 months: May 2017 (month 77/120):

As usual the data sheet is  available here.


Update at 6 years 4 months: April 2017 (month 76/120):

Update at 6 years 3 months: March 2017 (month 75/120):  Things are looking similar to what they were 3 months ago with the warmists continuing to lead the bet.  As usual the data sheet is  available here.


Update at 6 years: December 2016 (month 72/120):  Reporting once again that things are much the same as the previous report.  The green line remains on top and the warmists continue to lead the bet.  The effect of the just started La Nina is looking quite weak as suggested by NASA/GWPF below.  The effect is barely visible in the graph … to date anyway.  I’ve also heard that there might be another El Nino coming – if that’s the case then the warmists will get another push toward a win.  Certainly is an interesting race as we get closer to the finish line.   The data sheet is  available here.

Climate Bet, Dec 2016

Update: October 2016 (month 70/120):  Much the same as the previous report.  The green line remains on top and the warmists continue to lead the bet.  The warming effect of the recent large El Nino clearly visible.  I’m now wondering how much impact the ‘just started’ La Nina will have.  NASA/GWPF say it could be ‘weak’.


Update: August 2016 (month 68/120):  The green line remains on top and the warmists lead the bet.  The spreadsheet containing all the data and workings is  available here.


Update: June 2016 (month 66/120): The green line’s slope has started to turn down a little, but it remains on top and the warmists continue to lead.  I’m guessing the green line will cross back under the red in five or six months as El Nino fades out and La Nina arrives.

Climate Bet, Jun 2016The data is available as usual at the links below.

Update: May 2016 (month 65/120):  The El Nino has now nudged the green line and we now have the warmists in the lead by a small margin.

Climate Bet, May 2016

The spreadsheet is available here.

UAH v6 Beta 5 data is available here.

RSS v3.3 data is available here.

Update: March 2016 (month 63/120):  We’re still seeing the effect of the El Nino nudging the green line closer.  Whether the lines cross over, and for how long, is still uncertain.  The El Nino indicators seem to have peaked and are beginning to decline, but as Bob Tisdale described at his blog, ‘Every El Nino is different’.

Climate Bet, Mar 2016

Update: February 2016 (month 62/120):  We’re now seeing the effect of the El Nino, and the race is closer still, with the coolists still leading.

Climate Bet, Feb 2016Note:  Links to source data and spreadsheet at bottom of page.


Update: December 2015 (month 60/120):

We’re now at the half way mark; and the present decade is still running cooler than the preceding decade.

The average temperature anomaly for the previous decade (Jan 2001 to Dec 2010) is 0.202 C.  The average temperature anomaly for the past 5 years (Jan 2011 to Dec 2015) is 0.184 C.  Only 0.018 C difference.

The recent uptick at months 58 through 60 is the beginning of the atmospheric warming caused by the current El Nino. It’s barely visible but definitely there. But I wonder how long it will last? If it continues along the lines of the 2010 El Nino, (which lasted about 9 months with an average anomaly of about 0.47 C) the lines will be very close in July 2016, and the lead could pass to the warmists. However, a La Nina typically follows an El Nino. La Nina brings a cooling, which would likely pass the lead back to the coolists.

Keep watching … I plan to update this each 2 or 3 months.

Climate Bet, Dec 2015


A global decadal temperature bet was made in early 2011.

At the time the bet was made (early 2011) December 2010 marked the end of the previous ten year period. January 2011 marked the beginning of the next decade. The transition stimulated the formation of a decadal global climate bet.

And so the coolists (led by Pierre Gosselin – NoTricksZone) and the warmists (led by Rob Honeycutt – Skeptical Science) are having a bet. They agreed to use a composite of Remote Sensing Systems (RSS) and University of Alabama Huntsville (UAH) lower troposphere temperature – close to the earth’s surface. They agreed that the result would be accepted without quibbling, as it was agreed between them that those series are the best that we’ve got. The average of the two series will decide the bet!

I have shown ‘the race’ as it progresses by graphing an accumulating total, ie: adding 1/120th of the average of the UAH and RSS monthly global anomalies month by month. The sum of these numbers after 120 months (10 years) is of course the global decadal average.

Data Links:

The spreadsheet is available here.

UAH v6 Beta 5 data is available here.

RSS v3.3 data is available here.

27 Responses to The Decadal Global Climate Bet

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  8. Barry Brill says:

    After Bob Carter pointed out “the pause” in 2007, the alarmists have been keen to talk a lot about decadal temperatures.

    This graph is very illuminating but it is, of course, all intra-pause. Could you produce another version, which shows the decades of the 1990s and 1980s as well?

  9. Tom Curtis says:

    With regard to your graph, it misses the key point that in order to win the bet, the 2010s temperature must be below the average rate of increase over the full decade of the 2000s, not just the decade to date. Thus, if the green line were to fall back to the red line over the next six months, and sustain the same average rate of increase thereafter, the climate “skeptics” would lose the bet. Your graph would be improved by including a benchmark showing the mean rate of increase over the full decade of the 2010s as in this example.

    • Anthony says:

      That’s a good idea Tom. I’ll add an average line for the 2000 to 2010 series with the August update. I hope to do that next weekend; 10 or 11 September.

  10. Interesting stuff, Anthony, and I’m glad to have chanced across your blog.

    I too am interested in “accumulated” data, but I use cumulative sums relative to a base level, most frequently the mean for the period under consideration. Have been doing this since 1992 with climate data, so have made many thousands of cusum plots for a very wide range of parameters.
    These plots -which I can’t post here because I do not know how, but can readily send as GIFs or JPEGs by email -, are a telling means of assessing climate time series. They provide immediate information on the large scale historical behaviour of the series, enabling a rational decision on whether the almost ubiquitous linear model espoused by climate scientists has any support from the actual data.
    I am especially interested in abrupt change. This is what cusum technology, such as it is, was designed for in the 1950s, in connection with SQC. It worked then, using (perforce) hand calculation, and it works now.
    I would be very happy to send you details of my analyses of any data set you choose, provided that I can download it. Just contact me by email.

    Cheers, Robin

    • Anthony says:

      Thanks for making contact Robin. I would be interested if you have done a cumulative sum of outgoing long wave infra-red over say 10 year periods. I had a go at this with an earlier post and wouldn’t mind comparing results if you have.

  11. Jane Doe says:

    You wrote: “Update: June 2016 (month 66/120): … I’m guessing the green line will cross back under the red in five or six months as El Nino fades out and La Nina arrives.”

    Sorry, but it’s now seven months later and with Roy’s latest post about UAH (+0.30 in January) there’s still no sign of the green line turning back.

    My guess is that the green line stays comfortably above the red one for the remaining 47 months, and that Pierre Gosselin’s crowd has to pay up.

    I’m also guessing that many of them will blame it on the 2016 El Nino.

    Then there’s the issue of changes to the data series. When UAH switched their LT product from 5.6 to 6.0, it gave a boost to the “cooling” side. (For 2011-2016, the UAH/RSS average is 0.3 with the “old” UAH but only 0.24 with the “new” one.) If RSS eventually updates their LT product to v4, it will probably have the opposite effect. This will give the NTZ readers another thing to complain about.

    • Anthony says:

      Hi Jane, yes, my guess back in June 2016 certainly underestimated the effect of the El Nino. And since then the following La Nina was small, and now we have another El Nino forming. And the likelihood of the green line crossing back under the red looking much less likely, especially as Annie points out, there’s the 10 year anniversary of the 2008 La Nina to contend with.
      I can’t comment much on the tweaks to the UAH, and maybe later RSS series. I do notice the tweaks of course, but I just do my best to reflect their latest data sets accurately.

  12. Annie says:

    It continues to be quite warm. And we’re now approaching the 10-year anniversary of the very cold year of 2008 … which will make it extremely difficult for the “coolists” to regain the lead. So my guess is that this race is basically over now; it’s just a matter of waiting for the inevitable.

    It’s too bad, really. Mostly because for the sake of the planet I’d be happier if there were in fact some strong negative feedback that acted to stabilize the climate and prevent it from warming/cooling. That would be nice.

    But also because as I understand it the “warmists” pledged quite a bit more money towards this bet than the “coolists” did. So if the “coolists” won, it would be a better deal for charity. But that seems unlikely.

    • Anthony says:

      Hi Annie, yes – as we approach to 10 year anniversary of the 2008 La Nina, it seems very unlikely that the coolists will regain the lead. However, even though the race looks like it might be over, I will aim to update every two or three months.

  13. barry says:

    I see the data sets have been updated and reflected here (new UAH version).

    I’m curious about the use of UAHv6.5. The methods paper hasn’t been published as yet.

    What is the cut-off for new versions of the satellite data as you approach the finish line? As soon as beta data appear on the net or something else?

  14. DavidR says:


    RSS TLT dataset now updated from V_3.3 to V_4.0, accompanied by peer reviewed publication:

    Big increase in RSS rate of warming since 2001 which affects both decadal periods, but the latest one much more so.

    As of the latest month (month 77) the current decade stands at 0.317C versus 0.203C for the previous decade.

    Latest RSS TLT data to May 2017 available here:

    • Anthony says:

      Thanks David, I’ve been waiting for their updated series. Seems RSS’s update has turned out pretty much as Roy Spencer predicted about 6 months ago. Some commentary at Paul Homewood’s site covering the update.

    • Annie says:

      Paul Homewood’s reaction is slightly disappointing. The pattern is obvious here. A lot of people who call themselves “skeptics” were pleased to see Spencer and Christy adjusting their trend downward from UAH 5.6 to 6.0, but are furious that Mears and Wentz have similarly adjusted RSS upward.

      It makes me question how many people who call themselves “skeptics” are genuinely “skeptical” as opposed to simply being firmly committed to one side.

      Ironically, for those of us who have been averaging UAH and RSS, this brings us back to where we were before either of the updates. As of right now, the average of the trends in the old versions is 0.15 C/decade … and the average of the trends in the new versions is ALSO 0.15 C/decade.

      So ignore all the sturm und drang, and carry on with the graphs. We’ll see where this bet ends up.

      • Anthony says:

        Thanks for your thoughts Annie. Yep, I shall carry on with the graphs using the most up to date data from UAH and RSS as originally intended.

  15. MikeR says:

    Hi Anthony, yes the newer version of the RSS data greatly enhances the lead for the current decade compared to the previous decade.

    Currently using the old figures incorporating v3.3, the lead is 16% but using the new RSS version the lead jumps to 24%. It is going to require a massive volcano or a the arrival of a sudden ice age for the fat lady to change her tune.

    A prolonged La Nina is not going to cut it as the average UAH and RSS would be required to average 0.1 C or lower for the next 41 months. The last time the average over 41 months was that low, was June 1996. Anything is possible but this bet appears to be over.

    • Annie says:

      It’s interesting that under the older versions of both UAH and RSS, the current decade’s lead would actually be much larger. The lead became smaller when UAH was updated but RSS wasn’t yet. Then it increased again when RSS was finally updated, but still not as high as it would have been if one had stuck with the original versions of UAH 5.6 and RSS 3.3.

  16. darcy says:

    Thanks for the monthly update. I agree with your comment that “it’s highly likely the warming team will win the bet … unless a major La Nina turns down the thermostat several notches, or a huge volcano blows it’s top.”

    In fact, I don’t think either of those would be enough. There were big volcanoes in ’82 (El Chichon) and ’91 (Pinatubo), and five La Ninas during the satellite record. But the kind of cooling you’d need for the current decade to drop below the previous decade hasn’t ever occurred in the satellite record.

    As you note on your chart, the average (RSS & UAH) for the previous decade was 0.243. We are 78 months into the current decade and the average is 0.320. In order to end up cooler than the previous decade, the remaining 42 months would have to average 0.100 or lower. Thus, the difference between the next 42 months and the previous 78 months would have to be at least 0.22.

    The largest 42-month cooling in the satellite record (relative to its preceding 78 months) is 0.077, starting in the fall of 1991 (i.e., Pinatubo). The next largest cooling period started in late 2007 (i.e., the 2008 and 2010 La Ninas), and was 0.064.

    So the cooling required for the “warmists” to lose this bet would be approx three times larger than anything in the satellite record. Maybe a record-breaking volcano at the same time as a record-breaking La Nina would do it? Throw in an asteroid strike and it’s possible, sure.

    Nice blog, by the way.

    • Anthony says:

      Thanks for the analytical comments Darcy. I think I’d rather “suffer” a little warming than be struck by an asteroid and/or volcano debris. And thanks too, for the compliment.

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