The Decline, the Stick and The Trick – Part 1

One of the central claims of The Trick, if not the most central claim, was that “hiding the decline” was nothing more than an inopportune phrase about a single diagram.

It wasn’t. 

The “trick to hide the decline” was an inopportune, if revealing, phrase, but rather than the issue being limited to a single diagram, the inconsistency between the Decline (in observed tree ring widths and densities) and the Hockey Stick temperature reconstructions (primarily based on tree ring widths) was, together with the looting of the Baghdad Museum, the issue that inspired my original examination of Michael Mann’s Hockey Stick and was the driving theme of Climate Audit from its origin up to Climategate.  There are dozens, even hundreds, of Climate Audit articles that, in one way or another, relate back to the conundrum arising from the inconsistency of the underlying proxies and the superficial consistency of the reconstructions.

In this and a couple of follow-on articles, I’ll illustrate the centrality of The Decline vs The Stick in the controversies in the years prior to Climategate.  For the benefit of people that may be new to these disputes, I re-iterate that I never interpreted the late 20th century decline in ring widths as evidence of a decline in temperatures, but as a seriously problematic inconsistency for “reconstructions” relying in large part on tree rings.

April 2003

When I say that the Decline inspired my original examination of Michael Mann’s Stick, it is literally true.

I had become mildly interested in climate issues in late 2002 when the Canadian government was promoting the Kyoto treaty, including in its promotion the assertion that 1998 was the “warmest year” in 1000 years.  This was based on the 2001 IPCC Assessment Report, which included multiple versions of the Hockey Stick graph, one of which was the following:


In early April 2003 (while the Iraq invasion was going on), I read Briffa et al (2001, JGR) and noticed its passing reference to an “anomalous decline in tree density measurements over recent decades”.  I wondered why this effect had not been observed and/or reported in Mann et al 1998. On April 3, 2003, I posted a comment on this conundrum at a Yahoogroups chatline. In this comment, I also observed that there wasn’t anything exceptional in the “non-tree-ring proxy series” used by Mann. (I was referring here to data from Mann et al 1999 then available online at UMass. This was the small subset of Mann et al 1998 proxies used in the AD1000 reconstruction step. The data for the much larger MBH98 dataset was then not publicly available.)

Here’s what I wrote (at the very dawn of my interest) in a comment entitled “Briffa on post-1960 tree rings”:

Keith R. Briffa, Timothy J. Osborn, Fritz H. Schweingruber, Ian C. Harris, Philip D. Jones, Stepan G. Shiyatov, Eugene A. Vaganov, 2001, Low-frequency temperature variations from a northern tree ring density network, JGR, 106 D3 (16-Feb-2001) 2929-2941,, “We used simple linear regression, fitting the regression equations over the period 1881-1960, or over the total available period prior to 1960 when the instrumental record was shorter. The period after 1960 was not used to avoid bias in the regression coefficients that could be generated by an anomalous decline in tree density measurements over recent decades, that is not forced by temperature [Briffa et al 1998b: Nature 391, 678-682]”

At face value, this looks to me like quite peculiar statistical methodology … As to Mann’s methodology, I must confess that I am unable to understand it. But in any event, if Briffa observed the above effect, then (1) Mann should have observed the effect also and his failure to observe it would diminish the value of his study; (2) if Mann observed the effect, but failed to report it, then that would equally diminish the value of his study. Either way, I’d be inclined to rely on Briffa’s evidence as to observations and to rely on neither series as a proxy reconstruction for the obvious reasons above.

I have examined most of the non-tree-ring proxy series used by Mann e.g. Quelccaya O18 and accumulation, etc. and, through inspection only, have seen no evidence of 20C variables breaking new ground, although they are on the warm side.  I’ve posted up previously a note on O18 in a Greenland snow-pit. I collected this information specifically as an O18 measurement in the 1990s. 

Over the next few days, I wrote several further comments in the Briffa on post-1960 tree rings thread. In one comment, I compared the need to look at underlying data to the requirement that independent geologists look at drill core in mining projects (a key step in due diligence that was omitted in the Bre-X fraud.)

On April 8, 2003, I sent my initial request to Michael Mann for the FTP location of Mann et al 1998 data in order to look at the underlying data.

April 8, 2003 was also the date that looting began in Baghdad. On April 9-10, 2003, the Baghdad Museum, a totally unique repository of cuneiform tablets from early world civilization, was looted as a result of appalling negligence of cultural heritage by the US occupation, which devoted resources to protecting Toyota Land Cruisers, but not unique world history. I had a considerable prior interest in Bronze Age history and watched the spectacle with both dismay and anger.  I later wrote some (now lost) comments entitled “Day of infamy at the Baghdad Museum”. 

The connection between the looting of Baghdad and my decision to request MBH98 data wasn’t just coincidence. The looting of Baghdad was a radicalizing moment for me: whatever the rights or wrongs of the invasion itself, it was evident that there were no plans on what to do now. It was a mess. Making matters worse, I had begun with substantial skepticism of the WMD rationale and presumed that Iraqi emigres were telling too eager US intel agencies exactly what they wanted to hear.  Was it possible that something similar was going on with climate? In the sense that everyone in climate, like everyone in the days leading up to the Iraq invasion, was too eager to go to war. 

I discussed this issue on a few occasions in some early Climate Audit posts. The primary rationale for the Iraq war was supposed proxy evidence of WMD, such as the now infamous aluminum tubes.  The (then) lead argument from Canadian and other governments – the late 20th century climate uniqueness  of the Hockey Stick – was similarly based on proxy evidence.  I likened my parsing of the proxy reconstructions of temperature to what a pre-war (CIA) analyst ought to have asked in respect to proxy evidence of WMD: does the proxy evidence unequivocally prove the conclusion? Or are there alternative possibilities that would account for the proxy evidence?  Here are a couple of excerpts:

In an emotional debate, I think that there’s an important role for analyzing individual arguments being relied upon. I’ve focused on the multiproxy studies and have come to the conclusion that all the hockey-stick studies are flawed and biased. De-constructing each individual study is very time-consuming. I view this exercise as not dissimilar to that of a pre-war analyst studying proxy evidence for WMD such as aluminum tubes. At the end of the day, an analyst is sometimes obliged to say that maybe an aluminum tube is just an aluminum tube. That does not mean that some other piece of evidence may not be valid – only that the aluminum tube wasn’t.:

Back when views on Iraq were more evenly divided, I sometimes compared what I do to being a CIA analyst arguing that sometimes an aluminum tube is just an aluminum tube and not evidence of WMD. That wouldn’t mean that proponents of the war couldn’t argue the matter using different arguments or that the war was or wasn’t justified, or that the subsequent occupation of Iraq was or wasn’t botched. All it means is that policy-makers shouldn’t be basing their decisions on questionable information about aluminum tubes. This was a line of argument that used to rub right-wing people who liked part of my message the wrong way, but I hope that it says something about me.:

{Nor would] a belated discovery of some other type of WMD in Iraq vindicate Powell’s claim that aluminum tubes were conclusive proxy evidence of WMD.):

I’ve been very consistent in viewing the parsing of proxy reconstructions as a very narrow point in the larger climate debate.  In the sense that I’ve never argued that climate policy should be disdained because Hockey Stick studies were flawed. Or that we know that it was warmer in the medieval period than at present. My point was very narrow and consistent with my opening question about the Decline vs the Stick: that there was a fundamental inconsistency between the observed decline in tree ring widths and densities in the late 20th century (Briffa et al, 1998) and temperature reconstructions from proxy networks dominated by tree rings (Mann et al 1998).  This was a scientific question. 

Ironically, I recently read the original 2005 WMD Commission report in connection with the re-consideration of the Russiagate hoax in our “corner” of Twitter.  It turns out that US intel agencies committed more or less exactly the same procedural errors in respect to Danchenko (Steele) as they had previously with Curveball and claims that the Iraq WMD programme had been reconstituted. With one important difference: in the case of Iraqi WMD, there was a concerted and prompt effort to understand how the intel agencies had got their analysis so wrong, whereas in the case of the Russiagate collusion hoax, there was a concerted effort by intel agencies to conceal the origins of the false information and perpetuate the hoax long after they knew otherwise. 

As a closing comment and teaser for subsequent posts, I am well aware that there are now at least several dozen proxy reconstructions that supposedly “vindicate” the MBH Hockey Stick and that a new avatar of the Hockey Stick (PAGES2K, 2019) has returned to its place of glory in the most recent IPCC Assessment Report by inclusion in the Summary of Policy-makers.  But none of these studies squarely confront, let alone resolve, the problems that occasioned my original interest in the field – a point that I hope to return to in this series. 


  1. chrimony
    Posted Nov 2, 2021 at 1:23 PM | Permalink

    This body still stinks. I’m surprised the BBC is dredging it up again. I like to point to this video as an excellent primer for “hide the decline” and Climategate:

    It’s from the Climate Discussion Nexus and features Mr. McIntyre.

    • dfhunter
      Posted Nov 2, 2021 at 7:49 PM | Permalink

      thanks for that link – sums things up well ?

    • Posted Nov 5, 2021 at 11:08 AM | Permalink

      Often people ask what’s the big revelation from Climategate. The answer is almost always Mike’s Nature trick to hide the decline. The defenders of Mann and the climate establishment thus claim: whatever doubts there are about MBH98’s methods are irrelevant since the hockey stick has independently been confirmed by others. Also, the decline is irrelevant since it wasn’t the real temperatures going down, (just the proxies used to make the hockey stick illusion).

      I disagree. The most important revelation was that Mann, Briffa and Jones were being directed by the IPCC’s Chris Folland to change the scientific findings and not “dilute the message”. Just think if this was one of the Koch brothers or a tobaccos company telling one of their scientists what their results needed to look like. In Folland’s case it was a 100 times worse since he was acting as a world official.

      But nobody pointed a finger at the IPCC. The investigation was of Mann, which was a whitewash in order to protect the establishment. Richard Muller’s outrage should have been expanded to include the IPCC. If Muller didn’t approve of MBH98’s methods he could have spoken up years before the 2009. The hockey stick had already been successfully challenged by McIntyre and McKitrick (2003) and MM (2005).

      As a result of Muller and others willing to look the other way from the root of the problem, climate establishment bias and politicization, the hockey stick lives in the just published IPCC assessment report, AR6.

      • Ashby Lynch
        Posted Dec 3, 2021 at 10:46 AM | Permalink

        I was unaware of this information on Mr Folland. Was this in the climategate emails? If so, could you quote and reference the email? Thanks.

        • Posted Dec 7, 2021 at 11:25 PM | Permalink

          Ashby, Thanks for asking. I should have included this link:

          The emails brought horrific transparency to what went on and certainly must still be going on out of public view. This is why the climate establishment saw it as a terrible crime and also why some climate scientists decided to distance themselves [ex. Rich Muller] or openly question the establishment [ex. Judith Curry}.

  2. Ian Random
    Posted Nov 2, 2021 at 5:16 PM | Permalink

    I always thought the detection of radioactive materials in the tunnel under the Euphrates in Iraq was significant. There was a supporting US document and some weapons inspector making the AM radio rounds. I didn’t know at the time stuff against the dominant narrative quickly disappears off the web.

  3. Posted Nov 2, 2021 at 7:08 PM | Permalink

    For those coming here to find out what “Mike’s trick to hide the decline” really meant here is UC Berkeley physics professor, Richard Muller, clearly explaining it in 2010 to his students. Remember, this was before it became apparent that the media and scientific establishment were not going to evercorrect the issue, Climategate or not. Muller is still a top physics professor but he likely does not give this lecture today. Silence is safer.

    • Posted Nov 3, 2021 at 1:43 PM | Permalink

      Muller brilliantly gets his students to catch the implications of decline when he points out the justification for erasing the data from 1960-on was the proxy’s decline when the known thermometer temperature was going up. Then he points to the graph’s pre-thermometer era and asks the students how do we know this is reliable? He attempts to feign a shrug of its importance (to the laughter of the audience).

      Muller could have gone even further to point out that the splicing of thermometer temperature, a different data type, onto ends of three completely different data types was an invalid presentation even regardless to the point that it was designed to be a “trick” to create the illusion of uniform agreement of the data in one direction when they were headed in the opposite.

      It should be pointed out that Muller’s chart is Phil Jones’s version, adopted from Michael Mann’s 1998,1999 Nature articles, in preparation for the 2001 meeting of the World Meteorological Society. Phil Jones is the person quoted as saying he intended to use “Mike’s Nature trick” to “hide the decline”.

      How important was this issue? This chart is the basis of Al Gore’s movie, “An Inconvenient Truth”, (ironically named). How important was the movie? It gained Gore the 2007 Nobel Peace Prize shared with the IPCC. Michael Mann has been heard many time claiming to be a Nobel Prize laureate. It was reprinted in hundreds of millions of children’s text books. And, but for Stephen McIntyre it would be the IPCC’s logo.

  4. Posted Nov 2, 2021 at 8:25 PM | Permalink

    The connection between the looting of Baghdad and my decision to request MBH98 data wasn’t just coincidence. The looting of Baghdad was a radicalizing moment for me: whatever the rights or wrongs of the invasion itself, it was evident that there were no plans on what to do now. It was a mess. Making matters worse, I had begun with substantial skepticism of the WMD rationale and presumed that Iraqi emigres were telling too eager US intel agencies exactly what they wanted to hear. Was it possible that something similar was going on with climate? In the sense that everyone in climate, like everyone in the days leading up to the Iraq invasion, was too eager to go to war.

    Incredibly helpful Steve. April 8, 2003 – date to remember.

  5. Posted Nov 2, 2021 at 9:07 PM | Permalink

    Thanks Steve, looking forward the rest of this series of posts.

  6. Geoff Sherrington
    Posted Nov 3, 2021 at 4:05 AM | Permalink

    Back in 2007, Steve kindly published some emails between Dr Phil Jones and me.
    The emails, to me, showed a person having difficulty with straight answers to straight questions.
    Steve commented in part “The amateurism of this is beyond belief.”
    Fast forward to now. Dr Phil has a movie made about him to highlight his survival after attacks by foul people. Climategate 2009 gets a part.
    Might I validly deduce that
    1. Some media people promote mistruth
    2. It is possible to become a celebrity despite poor science, morals and ethics
    3. In some ways, the older standards of science have been in decline
    4. There is a deeper, more worrying message also named “Hide the Decline.” The BBC can show how.
    Geoff S

  7. Philip
    Posted Nov 3, 2021 at 6:04 AM | Permalink

    looking forward to your analysis of the PAGES2K. Absolutely crucial to understand if this is still based on the same fallacies or if they really improved the proxy reconstruction in any way.

    regarding the climategate CRU hack: any connection to the later “hack” of the Australian Skeptics forum on which they prepared the bogus “97% consensus study”?

    As for Russiagate and DNC hack: Alperovich/Crowdstrike/FBI seem to have played key roles themselves:

  8. phi
    Posted Nov 3, 2021 at 6:21 AM | Permalink

    Stephen McIntyre,

    You wrote :
    “…I never interpreted the late 20th century decline in ring widths as evidence of a decline in temperatures, but as a seriously problematic inconsistency for “reconstructions” relying in large part on tree rings.

    In my humble opinion, it would be better not to have too much a priori on this question. Two observations:

    1. Proxies linked to temperature by physical phenomena of different natures show similar behavior in the 20th century. This consistency is particularly striking for proxies having a good high frequency correlation with temperature.

    2. The current indices of instrumental temperatures are based by construction on the conservation of short-term trends. The effect of this procedure on long-term trends is known and corresponds to an additional warming of about 0.5 ° C over the last 50 years of the 20th century. Temperature indices are therefore not a gold standard.

  9. Jeff Alberts
    Posted Nov 3, 2021 at 12:00 PM | Permalink

    “that there was a fundamental inconsistency between the observed decline in tree ring widths and densities in the late 20th century (Briffa et al, 1998) and temperature reconstructions from proxy networks dominated by tree rings (Mann et al 1998).”

    Should that be Briffa et al, 2001?

  10. Craig Loehle
    Posted Nov 6, 2021 at 4:31 PM | Permalink

    SM inspired me to address divergence from the fundamentals of tree growth. The result was Loehle, C. 2009. A Mathematical Analysis of the Divergence Problem in Dendroclimatology. Climatic Change 94:233-245.
    I concluded that the way trees grow, which is more of a parabola with temperature (up then down if it is too hot) makes determination of past temperature from ring width indeterminate for temperature changes that are more than trivial. The problem is worse if rainfall changes over time.
    My work was also mentioned several times in the emails. Mann hated my reconstruction (which used almost no tree data), which is not surprising.

  11. See - owe to Rich
    Posted Nov 8, 2021 at 4:02 PM | Permalink

    UEA has gone big on how the BBC ‘Trick’ documentary vindicates them – see .

    It includes the wonderful “But the science establishment, more than anywhere else, should have had faith in the scientific method and – in the early days of the ‘scandal’ – directly attacked the ludicrous claim that a hoax had been perpetrated on the world…”.

    • Geoff Sherrington
      Posted Nov 9, 2021 at 2:37 AM | Permalink

      See – owe to Rich
      “… should have had faith in the scientific method…”
      This was the Phil Jones whose famous email was more or less “Why should I make the data available to you,
      when your aim is to try and find something wrong with it.”
      See the whole story here –
      When I have viewed the BBC movie, I shall look for this quote.
      It is easy to forget that, as well as Steve, others of us had been questioning Prof Jones about his methodology a couple of years before Climategate broke in 2009. He had shown a view of his science already. Will we see it revealed?
      Geoff S

    • antonk2
      Posted Nov 9, 2021 at 7:55 AM | Permalink

      White male East Anglia scientists playing the victim card while nearby Glasgow’s COP26 is forcing the whole World into their favored straitjacket. A new crooked pinnacle of 2020’s wokism?

  12. Posted Nov 14, 2021 at 8:04 PM | Permalink

    Yes the handle of the hockey stick is unbelievable but the blade is real. The temperature has gone up, and up rapidly

    • Posted Dec 3, 2021 at 10:10 AM | Permalink

      “I believe that the recent warmth was probably matched about 1000 years ago.”
      -Keith Briffa in CRU email
      #Medieval Warming Period

    • Posted Feb 26, 2022 at 2:49 PM | Permalink

      The Hockey Sick consists of proxy data, unavoidably smoothed and attenuated in nature, seamlessly grafted on to accurate and volatile modern thermometer data, giving the false impression that they were all measured by the same means. The merging of smooth with spiky could be better likened to a bottle-brush than a hockey-stick. The contrast leaps out as being very striking, and indeed, alarming! The question is whether that contrast would still be so evident if we had thermometer data going back for millennia (rather than relying on possibly dubious proxies.)

  13. Geoff Noakes
    Posted Nov 24, 2021 at 3:08 PM | Permalink

    Stephen, is there a “Part 2” that follows “The Decline, the Stick and The Trick – Part 1”? I cannot find it.



  14. Ashby Lynch
    Posted Dec 3, 2021 at 10:40 AM | Permalink

    Thanks for revisiting the cause for your original interest, and the comparisons to current events.
    One never knows which particular piece of information or study will rise to forefront of the decision process. It seems that some sort of critical information or study becomes the hinge of an argument, and becomes a totem for each side. Disinterested analysis of that information then becomes very difficult. Thanks, Mr. McIntyre, for pursuing such rigorous disinterested analysis.

  15. Posted Jan 2, 2022 at 10:47 PM | Permalink

    The question of WMD in Iraq could be a long hot discussion, but I only note some factors you have not:
    – Saddam Hussein bragged he had WMD, appears he conned the world, just as climate catastrophists are doing, and just as the in-country geology manager for the Bre-X project did.
    (Israel had destroyed an Iraqi nuclear complex, after Iran destroyed supporting buildings, Hussein may have decided that it would do so again thus he would spend the money on other things instead.)
    – chemical WMD left from the Iran-Iraq war was found
    – It is conceivable some things were spirited out of Iraq while US forces were stumbling around not controlling activity, as artifacts were spirited out of the museum you speak of. Syria would be a likely destination, perhaps Iran.

  16. Posted Jan 8, 2022 at 9:26 AM | Permalink

    And your data is?

    Obviously not:
    – weather balloons and satellite sensors
    – tide gages collated at
    – basic physics of greenhouse gases which limits amount of temperature rise possible from CO2 (the ‘saturation effect’ of overlap of absorption-emission spectra of carbon dioxide and dihydrogen monoxide vapor)

    Sounds like emotions are your data, negative ones.

    • Posted Jan 8, 2022 at 9:28 AM | Permalink

      My question about data was to ‘Donald Rapp’, WorsePress did not attach it to his claim about rising temperatures, as it has others.

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  1. […] same goes for the rest of our examples. Mining executive Stephen McIntyre has a white whale-sized obsession with Michael Mann’s iconic hockey-stick graphs, and in the 00’s launched information requests […]

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