Engaging with “skeptics”

Sou has a recent post about why scientists talk to contrarians. This all started when Andrew Montford (Bishop Hill) reported on a talk by Rob Wilson. In this talk Rob discussed the analysis used by Michael Mann and colleagues to produce their millennial temperature construction, now referred to as the hockey stick. Rob also referred to some of Michael Mann’s recent work as a “crock of xxxx”.

To a certain extent, this whole exchange rather confused me as I had thought that the basic hockey stick had been replicated a number of different times in a number of different ways. I wrote a post about this confusion (Hockey Sticks and things) and a number of people who appear to be experts in millennial temperature reconstructions, including Rob Wilson, responded to clarify the position. Although there are still uncertainties and disagreements about some of the details, the basic picture seems robust. There was a medieval warm period (that may have been similar to today, but may not have been global), a gradual cooling towards the little ice age, and then the modern warming. Millennial temperature reconstructions continue to produce a hockey stick-like shape.

So, although there may have been some issues with the original Mann analysis (not surprising, given that it was an early attempt at such a detailed reconstruction) the basic picture has not changed much in 15 years. Rob Wilson then commented on the Bishop Hill post to make clear that

the “crock of xxxx” statement was focussed entirely on recent work By Michael Mann w.r.t. hypothesised missing rings in tree-ring records (a whole bunch of papers listed below). Although a rather flippant statement, I stand by it and Mann is well aware of my criticisms (privately and through the peer reviewed literature) of his recent work.

So, the “crock of xxxx” statements refers only to the recent work by Michael Mann on missing rings in the tree-ring record and not to his work that produced the hockey stick. Good, that’s very clear. However, two Bishop Hill posts later, we get the following cartoon (yes, I know I probably shouldn’t show it, but it’s part of the narrative)

credit : Bishop Hill, cartoons by Josh

credit : Bishop Hill, cartoons by Josh

Essentially, a scientist who willingly engages on Bishop Hill refers to Michael Mann’s work as a “crock of xxxx” – but makes it very clear that this refers only to his recent work on missing tree-rings and not to his hockey stick – and the site then promotes a cartoon that very clearly links the “crock of xxxx” statement to the hockey stick.

As far as I can tell, this appears to be a very obvious mis-representation of what was said about Michael Mann’s work and is an illustration of why myself (and others, I think) are confused about what some hope to gain from engaging on such sites. Why would you be happy engaging on such sites only to find that they then mis-represent what you say. Furthermore, Michael Mann is a bit of flashpoint, so why wouldn’t those who engage on contrarian sites at least try to be careful about what they say about his work. I’m not suggesting that he should be treated specially, it just seems that maybe people should put a bit of care into making sure that what they say isn’t mis-interpreted. It’s one thing to criticise someone’s work, it’s another to do so in a way that then likely leads to unnecessary attacks on that person’s credibility (unless, of course, you think that’s warranted).

To be clear, though, I don’t think that those who engage on contrarian sites need to justify themselves to me or to anyone else, nor do they need to explain their motives. All I’m really trying to illustrate here is why some, like myself, are confused about what they hope to achieve by engaging on such sites. Personally, I’m in favour of trying to engage with those who are “skeptical” about climate science, I’m just not in favour of doing so in a way that ultimately just seems to provide more ammunition for them to then use to undermine the scientific evidence.

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82 Responses to Engaging with “skeptics”

  1. johnrussell40 says:

    I agree. For one respected climate scientist to attack the work of another climate scientist on a denial blog is doing a great disservice to climate science. That’s not to say that climate scientist should not argue robustly with one another in private, at conferences, in the literature—or, if they must, even in science-based blogs—but they must take account of the propaganda war being waged by those in denial and thus be careful not to damage climate communication.

    One of the things that climate contrarians instinctively do which helps their misguided cause no end, is almost never contradict one another. We know that to be a weakness, but in a PR battle it’s a tactic that works.

  2. toby52 says:

    Perhaps Robert Wilson might return and explain, not why he made the “crock” remark, but why he felt compelled not to apologise?

    In view of his more anodyne comments on this blog, I could not see why he said it in the first place. But we can all say things under the pressure of a moment, but I see still cannot understand the “stand by it” part.

    Dr Wilson might also disassociate himself with the BH blog, unless it clarifies its position. Montford is, after all, trying to sell a book and Wilson has ended up writing a blurb for it.

  3. That is essentially the issue. Part of what’s going on is a propaganda war/PR battle. I don’t think scientists need to try and engage in a propaganda war of their own, but I can’t see how providing “ammunition” for those who are playing such games helps to improve the public’s understanding of climate science.

  4. Given that I said that I don’t think that people need to justify what they do or explain their motives, I might word it slightly differently. It’s a free world, so do as you wish. However, if you’re going to engage on contrarian blogs and if those blogs both mis-represent what you say and you say that things (such as “crock of xxxx”) that appear to be precisely what these sites would like you to say, don’t be surprised if people seem confused/surprised by what you seem to be doing.

  5. chris says:

    Yes I also agree. As is often the case there are two issues; (1) the science : (ii) the perception, personalities, politics.

    (i) the science: in my understanding this is a relatively minor issue that relates to discrepencies between observed and modeled responses to volcanic eruptions on v short timescales (annual-sub-decadal). In their papers Mann and his colleagues have explained that this specific issue (and their interpretation of some missing tree rings following major eruptions) has little to say about the general nature of paleoreconstructions. Mann et al’s evidence and interpretation of a smearing out of high resolution paleodendro by some missing rings is a well-formulated published hypothesis – it’s up to Mann et al and the relevant scientific community to test this hypothesis and assess its validity. That’s science.

    (ii) perception and personalities: Wilson is pretty culpable for this nasty storm in a teacup in my opinion. There a quite a few papers and their interpretation in my research field that I disagree with. Some of them I consider are “crocks of shit”. We address this by attempting to provide evidence in support of our interpretations and publishing this if possible. Wilson’s approach of slagging off a fellow scientist in a lecture (not that big a deal in my opinion), but then allowing his comments to be misrepresented on a blog with a history of misrepresenting science and making unpleasant and cheap shots at scientists, is sad. It’s difficult to understand what Dr Wilson thinks he benefits from promoting nasty attacks on scientists.

  6. Steven says:

    Observe that Judith Curry, while defending herself against accusation she knowingly spreads false information, adduces by bullet point

    * Rob Wilson’s recent declaration that Mann’s reconstructions were a ‘crock of xxxx’

    A visitor points out the error to Curry in the comments section of her blog, politely asking her to make a correction. How does she opt to reply? Judith ignores the poster but acknowledges unrelated comments submitted at a later point in time!

  7. toby52 says:

    I am indeed confused & surprised as to why Wilson would stand by such a melodramatic and coarse reference to the work of another scientist on a denier blog, especially on the blog of someone who will use his remarks to sell more books.

    It is also offensive to see public discourse in scence become so inarticulate and vicious that such a remark does not warrant an apology. In private, just about acceptable; in public, unacceptable.

  8. And doesn’t appear to have corrected the post in any way.

  9. Marco says:

    I think some people on both sides forget that Mann’s “denier” comment came *not* in response to the CoS comment, but to the other comments Wilson made about MBH98/99, essentially repeating Montford’s narrative.

  10. Mike says:

    Sorry, this whole thing just seems so obvious. Go and talk to skeptics all you want, but you don’t disparage colleagues in such an obvious way while providing fodder for the anti-science crowd, At this blog, Robert Wilson answered selected questions about the science and so obviously avoided any questions that related to the effect of his comments at Bishop Hill. On BH, it would have been very easy to come out and say that the conclusions from Mann’s original work and others that followed are robust, but…blah blah there are important issues still and Mann’s recent work blah blah. He completely avoided saying that (other than everything after the but.) Given the original post at BH and the known audience at that blog, it’s disingenuous. Sometimes it’s not what you say, but what you don’t say (especially to whom). I don’t see why we should judge others any easier than we would judge ourselves. I would not have done what he did.

  11. To borrow Senior’s wording, Judy FAILED to disclose this:

    The “Mike’s presentation is dishonest” is a figure called personalisation.

    Coincidence? As honest brokers may say: you be the judge!

  12. Bwana_mkubwa says:

    Vociferous disagreements on science and even personality clashes are par for the course in science, but there are proper channels for this. The peer reviewed literature for instance.

    I said this on Sou’s site; By posting comments like this on a website with a clear politically inclined bias like BH, research scientists do become “political advocates,” whether they like it or not. Particularly when the only comments they present seem to be “knocking copy.”

  13. Not far from Mark’s request, which still meets crickets, there’s a comment by Kent Clibze:

    > Our opponents are skilled in this type of warfare. It is an espionage/intelligence art. The Soviets called it Active Measures, Americans call it Covert Action.


    As Yikes says, can’t wait to see the movie.

    Were you trained in Covert Action, Wotts?

  14. Joshua says:

    I think it is useful to access the actual impact of what Wilson did, or the impact of similar interactions.

    Some “skeptics” distort what climate scientists say, no matter what. If Wilson had been more careful, and qualified his comments more accurately, what difference would it have made? Would any “skeptics” have been less convinced of their opinions w/r/t climate change, or Mann’s work? Would the bent-on-distortion segment of”skeptics” have moderated their opinions in any way, and said, “Oh, Wilson’s reference was limited in nature, and therefore we can’t legitimately use it to trash Mann’s entire body of work?” I’d say absolutely not.

    “Skeptics” ,may use any ammunition that is offered to them, but don’t forget that they can manufacture their own ammunition at will – because they are not constrained by examining their opinions for bias. And having spent a lot of time observing “skeptics” on their home court, I can assure that perhaps the only thing that they enjoy more than comments like Wilson’s are when “realists” worry about comments like Wilson’s. My estimation is that this kind of post here actually becomes a kind of “ammunition,” of perhaps a more powerful sort than Wilson’s comments and participation at BH. When “skeptics” do what “skeptics” do on their blogs, they feed off of each other’s energy. But when they look around and see that “realists” are concerned about what they do, and whether they (the “skeptics”) have been given ammunition, they feel vindicated. They feel that they have impact beyond their limited circle. They feel more powerful, because “realists” are concerned. It’s as if energy has been added to their internal system from an external source.

    In the end, outside of a community of fanatics, of outliers, who are already fully convinced in their dismissal of concerns about the impact of ACO2 on the climate, what impact do Wilson’s comments, or his participation at BH, actually have?

    IMO, the point of focus, w/r/t comments and actions like those of Wilson, needs to be not the climate warriors who are already loaded for bear and armored beyond vulnerability, but on the vast majority of folks who are not so heavily-engaged.

  15. Steve Bloom says:

    a href=”http://www.bbc.co.uk/news/uk-politics-24650841″>Topical:

    ‘”It may be that one of the things conspiracy theories feed on as well as silence, is a surfeit of information. And when there is a mass of information out there, it becomes easier for people to find their way through to come to the conclusion they want to come to.

    ‘”Plus, you don’t have to be an especial cynic to believe that, in the age of open government, governments will be even more careful to keep secret the things they want to keep secret.

    ‘”The demand for openness always produces, as well as more openness, more secrecy.”

  16. Steve Bloom says:

    Fix close tag, pls.

  17. Lukewarmer says:

    What I hope you understand is that the scientific issues around Mann’s work are important and there is lots of evidence that his original reconstruction had lots of problems, amply commented on in the climategate emails in rather harsh terms by many mainstream scientists. The real issues however arose around the summary graph that appeared on the cover of an important journal. That graph was misleading and didn’t fairly represent the science. I hope people here are still not in denial about that. It is pretty obvious I think from all the source material. Another issue that has prolonged the agony is the very defensive reaction of the Real Climate group and the refusal to admit any problems. This is not science and it has I think been very counterproductive.

    The first prerequisite to being effective in the public sphere is to be fully honest and to correct errors and problems. That is the normal course of science and it has harmed the implementation of mitigation policy. It is all compounded by the appeals to deep dark conspiracy theories about the fossil fuel industry and their supposed paid mouthpieces.

  18. Louise says:

    Do you think Dr Curry should correct errors and problems too as referred to above? This is what annoys me about ‘skeptics’ and ‘lukewarmers’ – their hypocrisy when it comes to correcting others whose opinions support their own even when obviously wrong.

  19. Lukewarner,

    That graph was misleading and didn’t fairly represent the science.

    I think you need to expand on this. I’ve been reading other, more recent, papers that seem to produce temperature reconstructions that, broadly, match that produced by MBH98. I have a recent post with comments from some experts (including Rob Wilson) who acknowledge that the overall picture hasn’t changed much since MBH98. So, in what way did it not fairly represent the science?

  20. Marco says:

    It looks like lukewarmer has heard and read a lot, but not quite the factual accounts. First, there were not “many mainstream scientists” that commented on MBH998/99 in the climategate e-mails. Briffa and Cook, with Cook the most outspoken, yes, but it kinda stops there. Some wondered whether McIntyre’s criticism was right, but no major criticisms. Of course, if lukewarmer thinks it is important to correct errors and problems, one wonders why none of those concerned have asked McIntyre to correct his errors and problems, such as the cherry pick of the most extreme hockeystick shapes and a really extreme noise level, and that even with that cherry picking the signal was significantly larger than the actual hockeystick shape due to the noise.

    Then there was this “summary graph” that supposedly was on the front of an important journal and that was misleading. Most likely lukewarmer refers here to the graph made by Phil Jones (not Mike Mann) that was on the front of a ‘journal’ called PAGES, a publication of WMO that is far from an “important journal”. I truly wonder how lukewarmer managed to mix these things up. Serious question here, lukewarmer: did someone else manage to mix it up and you just trusted whatever he said, or did *you* mix these things up? Will we see you correct this false claim?

  21. Marco says:

    Wotts, I’ll put quite a few pounds on that Lukewarmer mixed two things up. See my comment below.

  22. Tom Curtis says:

    Assuming Lukewarmer is referring to the PAGES graph, then the following facts are pertinent:
    1) The data for the graph is credited to four sources of data, ie, the three reconstructions available in the IPCC TAR plus the HadCRUT3 instrumental values;
    2) The graph shows only three curves; and
    3) The graph cites papers showing the original reconstructions and, in the case of the Biffra reconstruction, shows and discusses the “decline” (ie, the divergence problem).

    So, while Jones may have “hid the decline”, having done so he gave us a map with the location of the decline marked by a large X, and arrows pointing to it. I think the graph in question is poor practice by Jones because it does not follow standard conventions, and therefore can mislead accidentally. The very clear paper trail Jones leaves, however, shows that there was no deliberate intent to mislead. I discuss this in more detail here.

    Beyond the issue of accidentally misleading people, it is difficult to imagine what Lukewarmer means by saying the graph did not accurately represent the science. The graphs accurately portray the three reconstructions prior to the twentieth century. In the twentieth century, they show a hybrid of reconstructed data and instrumental data, with instrumental data dominating in the later half of the century. Now, unless Lukewarmer is suggesting that the instrumental data is not part of the science, ie, that the only thing we know about twentieth century temperatures is the reconstructed values, we can say that the representation is not conventional, but we cannot say it does not accurately represent “the science”.

  23. toby52 says:

    In the end, outside of a community of fanatics, of outliers, who are already fully convinced in their dismissal of concerns about the impact of ACO2 on the climate, what impact do Wilson’s comments, or his participation at BH, actually have?

    Montford sells more of his rubbish book?

    Butin teh main you are right. I often wonder if blogosphere deniers are worth one-tenth of the energy spent refuting them. Deniers in politics, where real damage can be done (think Tony Abbott) are far more worthy targets.

  24. Commenters should beware sock puppetry:


    more so when raising concerns lukewarmingly.

  25. richard says:

    “However, two Bishop Hill posts later, we get the following cartoon”

    do you remember the video of skeptics being blown up or shot made by the organization below.

    10:10 is a movement of more than 100,000 people and organisations taking positive, practical action to tackle climate change.

  26. Firstly, I don’t approve of that video. Secondly, it’s not the point and I don’t see the relevance. The point I was making was that the “crock of xxxx” statement came from someone who very clearly stated that it referred only to Mann’s recent work on missing tree rings (hence, not to his hockey stick work). Personally, I’m not that bothered by the cartoon. It is just a cartoon and the person who draws it is quite a good cartoonist. It’s more that it clearly mis-represents what the “crock of xxxx” statement was referring to and, hence, appears to illustrate a common theme in this debate.

  27. richard says:

    I agree, sometimes the message in either cartoon or video format does not get across in the correct way.

  28. richard says:

    the video just seemed a strange way to Engage with “skeptics”

  29. I’m not sure if it was intended as a way to engage with skeptics but I was unaware of it until recently and, obviously, was in no way involved with it.

  30. Marco says:

    British humor does not always register, not even with British people. Look at Monthy Python: some hate it, some love it.

  31. Rachel says:

    I don’t find the crockey stick cartoon very funny. I must admit that I didn’t actually get it at first which is embarrassing given all the discussions and blog posts about the crock of shit episode. But sometimes I’m a bit slow 🙂

    Do contrarians find this cartoon funny?

    It is a misrepresentation though, true, but I think we accept a certain amount of ridiculousness from a cartoon. What is more irritating is the aftermath of crock of shit. People will think the statement was made in reference to the hockey stick even though it has been pointed out that this is not the case and it doesn’t matter how many times this clarification is made, they will still misrepresent it. It would be much better had the statement not been made at all.

  32. When I said I didn’t approve of the video, I didn’t say I didn’t laugh when I first saw it 🙂

  33. Rachel says:

    The video is great! Very funny.

  34. I can, however, see and understand why it wasn’t appropriate for the campaign. If it had been a Monty Python sketch, on the other hand, …..

  35. Tom Curtis says:

    Quite a good cartoonist judged only on his art work. His sense of humour depends strongly on accepting the “skeptic” world view, and is puerile at best without the crutch. Further, he has no apparent concern for the accuracy of the attacks on his targets, as evidenced by the “crock of XXX” example.

  36. Tom Curtis says:

    For the record, I am firmly of the belief that the video is merely offensive. The only context in which it could be considered funny is in lampooning “skeptic” claims of censorship, which is certainly not a concern of the general public, and hence not a joke for the general public (let alone “skeptics”). Even in that context, however, it is over the top. Monty Python fans may expect over the top humour, but when we watch Monty Python we know what we are going to get, which again contextualizes it. Thus, as humour the add misses two important contexts – but as a message it is simply immoral.

  37. Tom, yes that’s the problem I have with it. As something that was intended to be over the top (as might be expected from Monty Python) it could be seen as funny. As something that is trying to present an actual message, it is clearly inappropriate.

  38. BBD says:

    Have to agree with Tom C that the 10:10 video crossed the line. And, as ever, so what? Physics abides. Or as willard might have it, ‘yesbutphysics’.

  39. David Young says:

    I would not make a mountain out of a molehill. The cartoon is a cartoon but it does convey a common view of Mann, a stereotype that he keeps reinforcing by calling people names, stonewalling any legitimate questions, and seeing dark conspiracies all around him that are out to get him. However, it would appear from Tamsin and others that the issues with Mann’s early work are quite widespread. You know there are derogatory statements made in the Climategate emails by several people of whom I seem to remember Wilson is one. I don’t have the time to research this in detail, but its easy to do. 🙂 Please don’t tell me that “it’s early work.” If in fact there are methodological issues, why has no one associated with the paper admitted anything to be wrong, especially since it was the subject of an extended debate in Annals of Statistics. An honest view would be that “my early work is controversial and maybe there are some problems.”

    Muller I think speaks for many on the “uses” to which the work has been put by communicators that were truly wrong. In fact in the summary graph, the “declining” data was erased and replaced with thermometer data. This graph according to Muller appeared on the cover of the Journal of the World Meterological Assocation, if memory serves. And the declining data was hidden for years from at first polite and then legally binding attempts to get it. It was finally “leaked” and provided the final evidence of what was done. I have never seen any effective rebuttal of Muller’s exposition. If there is one, I’d like to see it.

    As long as the standoff continues, history will potentially judge the work harshly if in fact future science shows it to have been wrong in ways that should have been obvious.

  40. BBD says:

    Yes but PAGES-2k.

    Yes but Marcott.


  41. Doug Bostrom says:

    “…seeing dark conspiracies all around him that are out to get him.”

    Such as Cuccinelli, Competitive Enterprise Institute, etc.

    So, a common view among the fatuous. You can rewrite history to your heart’s content in the space between your ears but your domain of fantasy ends at the border of your skull.

    Running a whispering campaign is somewhat akin to lying about why your homework was not completed. More than one fabrication is counterproductive. Stick to planting just a single rumor and you’ll do better; uttering too many rubbishy innuendos tends to arouse suspicions, which causes people to scrutinize, which in turn ruins the whole approach.

  42. Tom Curtis says:

    David Young, I would take “skeptic” criticisms of the MBH 99 graph far more seriously if they got the details right. Let’s start with methodology, which indeed has been extensively criticized in the literature, most extensively by Michael Mann himself. Mann has published several papers examining the virtues and flaws of different methodologies, and updated his methodologies as a result. He has also taken note of criticisms of the inclusion of various proxies, and has published reconstructions excluding all controversial proxies, which show the same basic shape (see the light blue reconstruction) and differ primarily in that confidence in their “skill” declines more rapidly with age. While Mann has admitted the validity of some of the earlier criticisms by McIntyre and McKittrick, what he has not done is admit the validity of all of those criticisms, a perfectly justifiable action given that many of those criticisms are demonstrably invalid, and result in greater methodological flaws if acted on.

    Moving on, there was no declining data in MBH98 or MBH99, and therefore no “decline” for Mann to hide. Furthermore, in no graph that Mann published was data erased and replaced with temperature data. Mann did underlay the proxy reconstruction with the instrumental series for comparison, but I fail to see how there can be any serious objection to that. The actual “declining data”, from Briffa’s northern hemisphere tree ring reconstruction was published in scientific journals before his reconstruction was published; and the paper that included the reconstruction referred to the issue (from memory I cannot remember whether or not it directly discussed it, or merely referred to the prior paper).

    Finally, if you want a rebutal of some of Muller’s embarrassing (for him) nonsense, try here. The article includes the graph from Briffa (2000), complete with decline for all to see

  43. Tom Curtis says:

    Sorry, here for the response to Muller.

  44. David Young says:

    Tom, I skimmed the Sks link and like a lot of their stuff it doesn’t actually contradict Muller’s basic points. They of course do NOT show the graph with the “actual” proxy data plotted in full and contrast it with the graph as it appeared. That is a critical point. An effective response to Muller would seem to me to require that.

    What about the refusal to release the data? Mann could have done that at any time.

    I guess, the question is why include both proxy data and thermometer data on the same plot at all. If in fact, there is a “divergence” problem in the proxy data, how do we know that 1000 years ago there were not similar problems? It does tend to call in to question dendroclimatology as a whole.

    In any case, the real truth is as Wotts stated it, the Mideval Warm Period was real and may have been as warm as today even though there are still questions about whether MWP was truly worldwide. There is historical evidence that would tend to confirm that is was not just a local European phenomenon. We don’t really know and certainly treenomitors are not very helpful in answering this question.

    At least Schmidt was somewhat honest in defending the graph as a “summary graph” that did not include all the data and left some of it out. OK, but then why not release the data?

  45. David Young says:

    By the way, Marcott et al is in no way a vindication of the original graph. Marcott himself sent a nice note to a blogger where Keith Kloor used to blog explaining that NO conclusions whatsoever can be drawn from their work about the recent rate of warming compared to previous times.

  46. David Young says:

    BTW, Tom, the plot you linked shows that without the “controversial” proxies, the MWP appears warmer than the recent past and it seems to show that there were very rapid warming episodes around that time.

  47. BBD says:

    @David Young

    By the way, Marcott et al is in no way a vindication of the original graph. Marcott himself sent a nice note to a blogger where Keith Kloor used to blog explaining that NO conclusions whatsoever can be drawn from their work about the recent rate of warming compared to previous times.

    But one must not lose the context. Marcott et al. (2013):

    Our results indicate that global mean temperature for the decade 2000–2009 (34) has not yet exceeded the warmest temperatures of the early Holocene (5000 to 10,000 yr B.P.). These temperatures are, however, warmer than 82% of the Holocene distribution as represented by the Standard 5×5 stack, or 72% after making plausible corrections for inherent smoothing of the high frequencies in the stack (6) (Fig. 3). In contrast, the decadal mean global temperature of the early 20th century (1900–1909) was cooler than >95% of the Holocene distribution under both the Standard 5×5 and high-frequency corrected scenarios. Global temperature, therefore, has risen from near the coldest to the warmest levels of the Holocene within the past century, reversing the long-term cooling trend that began ~5000 yr B.P.

    Climate models project that temperatures are likely to exceed the full distribution of Holocene warmth by 2100 for all versions of the temperature stack (35) (Fig. 3), regardless of the greenhouse gas emission scenario considered (excluding the year 2000 constant composition scenario, which has already been exceeded). By 2100, global average temperatures will probably be 5 to 12 standard deviations above the Holocene temperature mean for the A1B scenario (35) based on our Standard 5×5 plus high-frequency addition stack (Fig. 3).

  48. Tom Curtis says:

    The plot shows a single peak at about 0.77 C greater than the 1961-1990 baseline, and three other peaks at about 0.65 C for the Northern Hemisphere Land surface temperature. Consulting CRUTem4v, we find a peak NH land surface temperature of 1.1 C, an average over the last 10 years of 0.94 C, and an average of the last 15 years of 0.9 C. It takes a fertile imagination to interpret that as the MWP being warmer than the “recent past”. That is evident from the graph, which shows modern instrumental values extend beyond any reconstructed peak in the MWP.

    Even that takes the no-dendro & minus 7 controversial proxies as being the most accurate reconstruction, which is far from obvious. It merely gives the “skeptics” all they can reasonably ask for. Further, given that it significantly reduces the number of proxies, it also increases the effect of regional variability. This is similar to the effect of using just 60 thermometers world wide to show modern changes in temperature. It shows the same pattern but more variability in detail simply because it is averaged across less regional variations. Likewise, it is probable that the sharper, higher and lower peaks in the no-dendro&minus 7 reconstruction relative other proxies is a matter of increased variability in the record due to fewer proxies rather than actual greater variability in the MWP temperatures.

  49. Tom Curtis says:

    BBD, Marcott et al benchmarked their reconstruction against a reconcstruction of the last 2000 years. Therefore they cannot validate that reconstructions other than to the extent of showing similar variability, nor others to any degree greater than the reconstruction they used (Mann et al, 2008) already does so. That does show the difference between MWP and LIA minimum is not much larger than shown in recent reconstructions but does not show the temperatures of both relative to twentieth century temperatures to have been correctly captures in the recent reconstructions.

  50. David Young says:

    This statement can only be arrived at by using instrumental data and comparing it to the proxy reconstruction. The proxy reconstruction is not meaningful for the 20th century. What is the rationale for comparing proxy “temperatures” with thermometer temperatures?

    I can’t find the Marcott quote at the moment, but he basically confirms my statement about the 20th century data.

  51. Tom Curtis says:

    What are you talking about? The graph they show includes the annual values of the reconstruction, and hence the “proxy data in full” if also in aggregate. Further, the graph shown (thin black line) is just the reconstruction shown in the IPCC TAR, with the only difference of consequence being the termination in 1960 (due to Briffa sending truncated data). What is more, the far more dubious PAGES graph is shown, ie, the only graph in which Jones’ “trick” was actually used (contrary to Muller’s claims).

    As to releasing the data, Mann obtained the data from publicly accessible databases, which he detailed. Given that the data was already publicly accessible, it was not incumbent on him to make a further release, and nor did his “not releasing” the data prevent any person from accessing it. I note further that the claim that he did not release the data is disputed by him. That you (and Muller) prefer to believe McIntyre’s account to Manns tells us nothing beyond the fact that you have already condemned Mann in abstentia. Where you fair minded on the issue, you would be agnostic about disputed matters of fact rather than condemning Mann simply on McIntyre’s say so.

  52. Young
    Would you believe the depravity in fraud?

    The article Tom provides, was put together with significant input from Michael Mann, and not Skepticalscience.

    See: http://www.bishop-hill.net/blog/2012/9/7/michael-mann-and-skepticalscience-well-orchestrated.html

    There is no more ‘rebuttal’ of Muller’s criticism in the article than what Mann himself would allow to pass!

  53. Tom Curtis says:

    Shub, it appears, thinks it is fraud to consult with somebody accused of performing a “trick” to find out what that “trick” was. I think that says a lot about Shub. Of course, we have already learnt about his basic scientific incompetence in the discussion on Salby.

  54. David Young says:

    This does not stand up to scrutiny Tom, If the data was publicly available why didn’t CRU just point to that instead or resisting the FOIA request? I am glad to see you admit that the PAGES graph is suspect. Perhaps there is common ground after all 🙂 So why has no one else admitted the problem with an iconic graph given a prominent place in the public discussion?

    Sks did not show the graph with the “actual” data as opposed to the spliced data unless I am not good at reading.

  55. Rachel says:

    The video is completely absurd, that’s why it is funny. Absurdity is funny. But I can understand that some people would find it offensive.

  56. Rachel says:

    I reckon the cartoon might have been better if he’d called it “the crockery stick” instead.

  57. David Young says:

    Shub, Fraud is too strong and not helpful. An ill advised public relations stunt is closer to the truth.

  58. Marcott said that the 20th century reconstruction was not “robust”. The reason was, if I remember correctly, because they started to lose proxies and hence were less confident about the 20th century portion of the reconstruction then the earlier portion. So this is an entirely scientifically correct thing to acknowledge, however, they were not stating that their 20th century portion was completely flawed. The uptick is clearly seen, it’s simply that it is not completely correctly representing the temperatures, which we know anyway from the instrumental record.

    Anyway, the main point of Marcott wasn’t really the 20th century portion, it was how global temperatures have varied for the last 11000 years (i.e., not very much).

  59. Steve Bloom says:

    Please talk about your views of the big-picture stuff, DY. I’m bored with the tedious nit-picking and demand some real red-meat denial. C’mon, I know you’ve got it in you…

  60. johnrussell40 says:

    The quibbling over temperature reconstructions by those in denial is terribly tiresome. More importantly it’s also a deliberate distraction from the most important evidence that no one can deny (can you David Young?); the massive increase in atmospheric CO2 concentrations that began at the point when humans started burning fossil fuels ( http://climate.nasa.gov/evidence ). This, unless you’re one of the few remaining ostriches who deny the greenhouse effect, has to lead to warming and, in fact, produce a ‘hockey stick’. Does the steepness and the precise shape of that hockey stick matter to us unless we’re a climate scientist? In the context of rapidly rising CO2, ‘medieval warm periods’, ‘little ice ages’, ‘pauses’ in surface temperature rise and other natural variabilities are all just questioning deckchair arrangements, while turning attention away from the underlying, undeniable, ‘big picture’ trend. In wasting time discussing such details with sceptics we’re aiding and abetting prevarication.

    The simple fact is that while ever CO2 carries on rising we need urgent action to curb it, and to find and adopt alternative ways to generate the clean energy we need. Let’s not get bogged down in details when we’re clearly heading for the buffers.

  61. Tom Curtis says:

    Wotts, the magnitude of the twentieth century uptick in Marcott et al is a result of their using a simple averageing method, with the result that drop off of low temperature proxies artificially inflates the magnitude of the tick. Tamino has a post in which he explores these issues. He also shows that, using a method of differences to overcome the problem, the tick still exists but only has about one quarter of the magnitude shown in Marcott et al.

    All of this should be merely a sidenote on methodology because Marcott did not compare reconstructed values with reconstructed twentieth century values to determine the effect. Rather, they compared instrumental values to members of their ensemble of randomized reconstructions to determine a probability of greater temperatures in the period of the reconstruction. In consequence, the magnitude of the reconstructed uptick has no impact on the Marcott result.

  62. Thanks, Tom. Yes, I remember Tamino’s post now. As you say, though, the reconstructed uptick is not really relevant to what they were illustrating in their paper.

  63. Tom Curtis says:

    David Young, your reply does not make sense. You write:

    “I am glad to see you admit that the PAGES graph is suspect. Perhaps there is common ground after all 🙂 So why has no one else admitted the problem with an iconic graph given a prominent place in the public discussion?”

    But the “iconic graph” that was given a prominent place in public discussion was that from MBH 99 which does not suffer the defects of the PAGES (WMO) graph constructed by Phil Jones. In contrast, Jones graph was published just once (ignoring occasions when it was published to discuss issues arising from the CRU hack), in a relatively obscure journal and would have sunk into complete obscurity apart from the notoriety resulting from “climategate”. Why should admitting the use of non-standard conventions which potentially mislead in the the PAGES graph require any admission of a problem with the MBH 99 graph? It is a complete non sequitur.

    It is particularly odd given that you have ignored my explicit discussion of the MBH 99 graph.

    The same odd skipping between graphs attends your comments on FOIA. I point out that the data for MBH 99 was available on public record, and you respond by bringing up the CRU FOIA requests, the vast majority of which deal with the instrumental record, and which certainly have no bearing on MBH 99. It is as though you want to note problems in obscure graphs which have been largely ignored in the public debate, and then simply assume the problems also apply to MBH 99 without any discussion.

  64. ” consult with somebody ”

    The fraud is perpetrated by you in this instance, and John Cook. I don’t see either of you acknowledge Mann’s role in authoring the article.

  65. Shub, can I ask that you avoid accusing others who are commenting on this thread of fraud. Not only do I fail to see that what Tom has presented could be regarded as fraud, it also does not constitute a constructive form of discussion.

  66. It is not misleading to you that Tom said this:

    “Finally, if you want a rebutal of some of Muller’s embarrassing (for him) nonsense, try here”

    when what he did was present a Michael Mann article?

    The entire series of articles at Skepticalscience has been re-written by John Cook in collaboration with Michael Mann, who has attempted to artificially divorce what he did in his Nature paper from Phil Jones’ impression of it, using Cook as a mouthpiece.

    You don’t find that disturbing, but my characterization bothers you?

  67. No, I don’t find it disturbing. Michael Mann is a scientist who is an expert at this topic (whatever you may think of him). Skeptical Science presenting an argument as to why what someone has said is wrong is an entirely reasonable thing to do. Getting help from an expert is also an entirely reasonable thing to do. Mann’s paper are cited in the skeptical science piece. To be honest, I don’t want to discuss this any further. It’s another example of trying to judge something on apparent fraud or misbehaviour, rather than on what’s actually said in the article itself. If you can’t rebut it using actual scientific evidence, I’m not interested in whether or not you think it’s fraud. I don’t wish this discussion to continue. If you can’t avoid making accusations of fraud to others who are commenting here, then I would ask that you simply don’t comment.

  68. If Mann is an expert, why do Cook and Curtis not acknowledge that articles what constitutes ‘hide the decline’ are written by Mann?

  69. Tom Curtis says:

    Wotts, are you sure you want Shub to stop the fraud accusations? Afterall, what was it Napoleon said? “Never interrupt an enemy when he is making an ass of himself.” Something like that, anyway.

    In this case I am waiting for the penny to drop with Shub that the article to which Bishop Hill refers is not the article to which I linked. I am also waiting for him to have basic honesty enough to acknowledge that when Cook writes, “So I read through Mike’s stuff, boiled it down to 3 essential points, cannabilised (sic) content from Dana, James and my own earlier stuff and compiled it into a single advanced version” (as quoted from Bishop Hill) he is indicating that he is using four distinct sources (Mann, his own earlier writings, Dana’s writings and James Wrights writings) and composing his own original text based on those sources. I am further waiting for him to be honest enough to admit that an article written by Cook, based on material by SkS authors, Cook, Dana, and James Wright (in addition to material by Mann) and then thrown open to review by the SkS team is an article with significant input by the SkS team (contra his claim that it “… was put together with significant input from Michael Mann, and not Skepticalscience”). Or to acknowledge that the article was written by Cook using material supplied by Mann (amongst other sources), and not authored by Mann (as he claims, thereby contradicting his own source). Finally, I am waiting for him to explain how this is my fraud when it occurred two months before my earliest contribution to the SkS forum.

    Of course, I’ll be waiting till hell freezes over for any of the above, so you won’t mind if I get on with other things while I’m waiting.

  70. Marco says:

    It will be interesting to see if David Young ever acknowledges that he has been conflating loads of issues, just like Muller did.

  71. OPatrick says:

    I think the comedy in the video comes from, or is intended to come from, the incongruity of juxtaposing the absurdist violent imagery with the utterly benign 10:10 campaign, which is as unthreatening, uncoercive and positive a campaign as you will find.

    The 10:10 people had been producing high quality and informative resources for a couple of years, which had reached everyone who was going to be willing to listen, and were, I suspect, looking for something different to draw attention to their work. There is no doubt that this attempt was misjudged, because the humour used – very clearly drawing on the tradition of Monty Python – whilst superficially quite crude can actually be unsettling and disorientating, which does not suit the message of their campaign.

    However, whilst they may have been guilty of misjudgement no-one who reflects on it for more than a moment will think there was any genuine intent to threaten or intimidate. Those most at fault then are the people who gleefully seized on this to imply the 10:10 campaign meant to do exactly that. We should take these opportunities to highlight this cynical manipulation by those who knowlingly and habitually mislead.

    Reflecting on this I wonder if we are missing some subtleties in richard’s equating of Josh’s cartoon with the 10:10 video. Given that it’s obvious the message of the 10:10 video is the opposite of the imagery used is he saying that this is true for Josh’s cartoon too? Perhaps then Josh is actually poking fun at those who have conflated criticism of Mann’s recent work with criticisms of his hockey stick, showing the absurdity of anyone making this confusion. Well, you never know.

  72. David Young says:

    I guess perhaps the crucial question that relates to a lot of these issues is what is the scientific justification for comparing inferred proxy data (which is NOT temperature but must be related to temperature by complex interactions) with thermometer data? That issue underlies the Mann question, the Muller question, and also some of Tom’s responses here. BTW, I still believe the Sks post actually supports Muller’s central contention that the PAGES graph is problematic. In fact it actually says its problematic, unless someone slipped up there. They just quibble with some of the secondary details.

  73. David Young says:

    Of course modern warming is closely related to greenhouse emissions. The critical question is the feedbacks which depend on the dynamics which everyone I’ve seen agrees are not very well modeled by GCM’s, that’s why regional climate is not well predicted.

    The problem here is how do we explain past climate changes which are substantial? They were almost certainly not due to GHG’s even though they constitute a feedback that is small compared to insulation changes locally. Changes in the DISTRIBUTION of solar insulation is clearly a major factor even though TOTAL forcing was almost constant. And this highlights the importance of the dynamics of the system. High lattitude summer insolution can vary as much as 40 W/m2 due to orbital changes.

  74. Tom Curtis says:

    David, it all depends on what you mean by “problematic”. If you mean “an example of scientific fraud”, then no, it is not problematic. If you mean, “doesn’t meet the best standards for presenting data”, then yes, it is problematic.

    I note, however, that it doesn’t meet the best standards primarily because it does not use the standard convention; which is based on a particular assumed purpose which was probably not relevant to the PAGES graph. In particular, the scientific convention is the important thing is not to show your result, but how you got the result. For that purpose, distinguishing between proxy and instrumental data is critical. However, in popular presentations, it is more reasonable to be interested in the best estimate of the changing temperature; for which using instrumental data to update or replace the reconstruction where they overlap makes eminent sense. (For that purpose, a convention requiring substitution of instrumental data for reconstructed data as early in the record as possible would be even better practice.)

    An example of that latter convention is the iconic graph that got replaced by the hockey stick, ie, Hubert Lamb’s schematic drawing of his estimate of temperature history. I note that he has not been criticized by McIntyre or others for not extending his graph based on anecdotal estimates through to the modern era so we can properly compare it to the section of the graph based on the Central England Temperature series. Nor has he been criticized for not plotting the global temperature series along side his estimate based on the CET through to the modern era. In fact, he has done something very similar to what Jones did in the PAGES graph. Again, not best practice, but nothing deserving a song and dance about it. Yet here we are a decade after the ball started, and “skeptics” are still playing the “Nature trick” Waltz.

  75. KR says:

    The real comparison is the Marcott data to current temperatures not counting the overlap, due to the reduction in proxies closer to the present that they themselves discussed. And from examining that data it is clear that current temperatures are reaching towards and will soon (on current trajectories) exceed anything else in the Holocene.

    I will note that both the Tamino style differencing or the RegEM method Marcott presented (but did not emphasize) do a better job of dealing with proxy drop-off, but Marcott et al stated the last 150 years are not the best data in their analysis. Of course, they calibrated their data to ~1000 years of proxy data which itself was calibrated to the instrumental record, as they state:

    “…we aligned the stack’s mean for the interval 510 to 1450 yr B.P. (where yr B.P. is years before 1950 CE) with the same interval’s mean of the global Climate Research Unit error-in-variables (CRU-EIV) composite temperature record, which is, in turn, referenced to the 1961–1990 CE instrumental mean…”

    Complaints about the last 150 years of Marcott et al reconstruction, unused for any calibration purpose, are irrelevant to the significant results for the rest of the 11000 year data. And, quite frankly, a sign to me that the person making such complaints hasn’t read the paper.

  76. David Young says:

    OK Tom, but what is the scientific basis for comparing tree ring width or oxygen isotope ratios to thermometer readings?

  77. KR says:

    David, even a quick scan via Google Scholar reveals copious amounts of information on topics such as oxygen isotope to temperature calibration. The same holds for tree ring calibrations to temperature.

    There is plenty of work establishing those calibrations, complete with active and robust discussions on the limits of uncertainty. That cannot be dismissed with a hand-wave; in fact the burden of proof would be on you to establish that the calibrations are insufficient.

  78. Tom Curtis says:

    David, both oxygen isotopes and tree ring width correlate with temperatures. In both cases, the relationship is known to be causal, ie, higher temperatures cause better growth for trees near the treeline (ie, the trees used in paleoreconstructions). Likewise, higher temperatures cause changes in δO18 ratios. Therefore both tree rings and oxygen isotopes carry a signal for temperature. That signal can be extracted by averaging. That is because the other signals in the proxies will vary independently over time, and cancel each other out, leaving a more or less pure temperature signal depending on how many proxies, and how many different types of proxies you can use. This temperature signal can then be benchmarked against the modern instrumental record by scaling by variance, and minimizing the RMSE between reconstruction and instrumental record.

    There can be reasonable arguments over the best method of “averaging” and of benchmarking against the instrumental record. There is no doubt that in principle the method should generate a reasonable approximation of the actual historical temperature record.

  79. Marco says:

    So, that would be a “not yet(?)”.

    No acknowledgment he conflated Mann and CRU. No acknowledgment that the PAGES (or rather, the WMO report) graph has nothing whatsoever to do with Mann.

    Sad, really.

  80. Rachel says:

    I actually think it’s very clever that they can calculate historical temperatures from tree rings, fossils, ice cores and corals. Finding a different way to do something is part of science and I’d have thought that if a number of different methods all paint a similar picture, then this would give greater weight to the underlying hypothesis. What is wrong with measuring the same thing in two different ways and then comparing them?

  81. Brad Keyes says:

    “Sou has a recent post about why scientists talk to contrarians.”

    There’s little point, as I see it. The conversation is predicated on an insult (“contrarians”) right from the start. It’s hard to blame intelligent people for disliking and distrusting “scientists” who patronize them.

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