First (of probably many) Error Acknowledgements

When a blogger makes mistakes she or he has several options. Ignore it and hope it goes away, muttering an acknowledgement in an obscure reply to a comment, refusing to believe she or he is wrong. I’ve probably done all of those in the past, although I’ve certainly been more likely to notice it in others.

In recent discussions of Matt Ridley’s essay on ten tests required prior to acceptance of current climate policy I made the rather bold statement that we have clear evidence that temperatures have been higher at various points in the Holocene.

Blogger and climate activist William Connelly (Update: William’s surname is Connolley–and as misspelling his name could easily be perceived as a provocation, I doubly regret this error.) challenged that statement and I found that I could not back it up.

I think it’s important that I acknowledge clear error where I can. (I’ve done it in the past, apologizing to Joe Romm, who I consider a very bad actor in the climate debates, when I accused him of writing that sea level rise was going to be absurdly high–he didn’t. He just quoted others who did.) So I hope to be starting a tradition here. I also hope I don’t have to take advantage of this new tradition frequently.

I’d like to open the comment thread for further discussion of Holocene temperatures for those who are interested.

Thanks William for pointing out my error.

41 responses to “First (of probably many) Error Acknowledgements

  1. Excellent Tom. You just placed yourself furlongs ahead of most of us.

  2. What’s funny about this is that when I made the statement I was thinking about temperatures at the beginning of the Holocene, not so much the MWP or the Roman period. And I thought I had seen charts that showed a dramatic rise in temperatures about 10K years ago.

    • Interesting, because I tend to focus on the last millennium or less, since tree rings is what I know (although my self education exercise at the moment is to get a better handle on corals). Even in that time frame there’s a lot of uncertainty, as is clear from the reconstructions. I definitely need to learn more about the Holocene “thermal maximum” idea. Clearly, whatever happened there–and something did–it was important to understand.

      • Thinking about it further, even if I did find a clear high temp signal 10,000 years ago I would have to ask myself if it wasn’t just an oscillating rebound from the end of the glacial period–so even if it’s there it might not be relevant.

  3. It would be nice if you could spell my name right, too.

    “climate activist” is essentially meaningless. I’m one, in the same sense that you are. But if it makes you happier to be labelling me, I won’t trouble you about it.

    • Thank you for not troubling me about it.

    • I have updated the spelling of your surname in the post. I regret the error.

    • It’s not meaningless. It’s the opposite. It’s can produce contemptible behaviour when intermingled with science. It means you “know” the answer then filter information to meet your convictions. That’s not science. But this is not limited to climate science or ecology/environmental science. We see the same behaviour over nuclear power, genetically modified crops, bioscience (anti-vax movements). The list is long and depressing.

      Of course, an activist would be expected to argue that the consequences of his actions are benign. Although activism is not necessarily bad either. So long as they up front about their beliefs. What is ultimately abhorrent is activism masquerading as objectivism.

  4. Conrad Dunkerson

    “I thought I had seen charts that showed a dramatic rise in temperatures about 10K years ago.”

    That would likely be either the start of the most recent Milankovitch warming cycle ~13000 years ago or the end of it (after the brief cooling of the Younger Dryas) ~9000 years ago. The uncertainty range around the peak of that warming extends both above and below current temperatures.

    “He [Romm] just quoted others who did [say that sea level rise would be absurdly high].”

    I think you’ll find that this isn’t true either. The claim that ‘climate scientists said that sea levels would rise 20 meters in three decades’ (or variations thereon) has always been fiction. Hence the lack of any name or source which can be checked… just generic phantom “others”.

  5. Conrad Dunkerson

    Yep, me. Saw your name and a link at WUWT and thought I’d stop by.

  6. Do you suppose Connolley will bother to correct you if you are too alarmist?

  7. Good show, Tom, and I wish we could see such humility and self-correction in all areas of the climate debates, both online and in the peer-reviewed literature. I have yet to see such a decently worded step-back from quite a number of experts, but as I’ve said before I claim no special knowledge or expertise in any aspect of climate sciences….. I am simply a citizen who wants to get a better idea of which claims and arguments to take most seriously in various policy debates which every voter has to try to make some judgments about. Your outlook and efforts here are most appreciated.

    FYI, here is a review essay which seems to be fairly wide ranging while emphasizing many areas in which more and better studies are needed:

    Click to access cp-6-591-2010.pdf

    The authors do seem confident that there were higher temperatures at some other points in the Holocene, although they emphasize uncertainties and limitations in the currently available records.

    • Thanks, Skphil, but I think we’re in danger of setting the bar for decent behavior too low…

    • Unfortunately, they used a 500 year window for their evaluations so as to focus only on the really slowly changing forcings (i.e. orbital), which doesn’t help in estimating natural variation at time scales of 0-100 years, which is what we really need. Plus, it was only for 60+ north latittude.

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  9. What are you retracting exactly?

    Specifically this:

    “I made the rather bold statement that we have clear evidence that temperatures have been higher at various points in the Holocene.”

    Did you mean to write something like this instead:

    “The balance of evidence in terms of probabilities suggest there were periods in the Holocene as warm as or warmer than today…”

    The Team don’t tend to retract the most egregious of errors. You seem to be apologising for too strong an emphasis.

  10. Hi Will,

    I think even your alternative phrasing would be misleading, even though I think it may be more correct than whatever alternative I might come up with.

    After all, even Keith Briffa wrote that MWP temperatures were probably as warm as today. So it’d be easy to say that. But given the growing uncertainties of available proxies (our confidence in them seems to be declining rather than increasing), I think I would just be repeating the mistakes of the activists if I were to say that.

    I certainly think it’s possible that temperatures were warmer in the Holocene. And I think it’s symptomatic of the almost diseased mentality of the worst of the activists to fight this point (as with every… blessed… point) so hard–as if one crack in the edifice will bring the entire structure down around them. If you visit Stoat right now you’ll see what I mean–I don’t want to give those guys a stroke.

    So I prefer to retract my statement in its entirety pending the discovery and analysis of better sources, better data.

    • Very little is certain in climate science. If you assert ‘x is true’ you can be reasonably taken to task. But I don’t see how writing “the balance of evidence available at the present time suggests x is true” can be untrue. If you’re saying that such a statement is misleading, there is almost nothing that can be said about temperatures past a few hundred years.

      • Tom, I agree with Will – retract your retraction. His reasoning is entirely sound.

      • Hi Will and Bob

        I don’t think it would be untrue. I do think it would be playing the same game as the activists. I’d rather just wait for real data.

      • You have advocates on the other side of the fence proclaiming, “prove us wrong”. It’s an odd inversion. Normally, if you make a claim, you should bring evidence to bear to support the claim. The way the debate is currently framed, one side can make claims without ambiguous evidence and gets to maintain those claims for the very reason that the evidence is ambiguous. Hence use of the phrase ‘consistent with’. Broken lawn ornaments is consisted with the theory they are being damaged by reckless garden elves, but this is not very much in way of actual evidential support for the existence of garden elves.

  11. Tom, the vast majority of time you write a good. You acknowledge when you are mistaken which leads me to trust what you say at other times.

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  13. HI Tom,

    There is ample evidence for a Mid Holocene warm period in the mid-northern latitudes of the northern hemisphere. There is apparently insufficient evidence to definitively conclude as such in the southern hemisphere, although there is some suggestion that it did occur there.

    See a usefull review at:

    Most of your readers probably already know that current warming is much more dramatic in the northern hemisphere:

    It seems reasonable to suspect the same for recent previous warm periods.

  14. All we have is proxies which are generally local not global and aren’t guaranteed reliable. Some better than others perhaps. But a couple of graphs in front of me seem to be relevant. Deuterium isotopes from a Greenland (GISP-2) ice core seem to show higher temperatures than now during the Minoan (c 3500 to 3300 BP) and Roman (c 2250 to 2050 BP). While deuterium from Law Dome ice core shows steady cooling from around 10,000 BP, which has not yet been reversed. The graphs are from Bob Carter’s Climate: the Counter-consensus, figs 4 and 5.

  15. Good on you for acknowledging the error.

    I’ll invite you to clarify a term you use pretty often — ‘activist’. By usage, you seem to mean anybody who thinks the sensitivity of climate to CO2 is something in the vicinity of what IPCC comes out with, or at least what is most supported by the literature irrespective of IPCC. That strikes me as a rather poor usage, as it includes the tens of thousands of scientists who work on various parts of understanding climate that you’ve never heard of, who have never posted to any blog, much less to have done anything politically active (like, say, engage in civil disobedience, run for office, or at least be telling people who they should be voting for).

    Merely going with the bulk of the scientific literature on a topic is hardly ‘activist’. Since you’re concerned about accuracy of labels, this’d be one to limit.

    • Hi Robert,

      Not the first time we’ve struggled with this, IIRC. In common usage I’m simply referring to those without a scientific background that have taken up the banner of fighting climate change. Implicit in that is my perception (which obviously is colored by my experience) that these folks are not overly fastidious about the means they use to advance their cause.

      But I’m not really thinking of scientists when I use the term. Even Jim Hansen has clearly marked out where he speaks politically from where he speaks scientifically–and I think he does a really good job. Almost all of those to whom I refer are much more like William Connolley or Tim Lambert than you or Bart Verheggen.

      It’s undoubtedly a loose term of convenience. I no longer wish to use the term alarmist, nor the term consensus. Got any suggestions?

  16. I’m simply referring to those without a scientific background that have taken up the banner of fighting climate change.

    And yet you refer to a “Senior Scientific Officer in the Physical Sciences Division in the Antarctic Climate and the Earth System project at the British Antarctic Survey” with a “DPhil from St Edmund Hall at the University of Oxford for his work on numerical analysis” as such? Now, Wikipedia, from whence I take those quotes, is often wrong but I’m pretty sure the broad strokes are correct in this case… The BAS seem to think he worked there once:

    • Yes, Quiet Waters, I am referring to him as an activist. Do you say he is not? I am somewhat careless as I use ‘activist’ as an alternative to more derogatory ones. I’m sure you’ll agree that his comportment is different from Robert Grumbine’s. Let me be specific:

      ‘Activists’: Lambert, Connolley
      ‘Scientists’: Grumbine

      Activists’: Secular Animist, dhogaza
      Normal people: Andrew Adams

  17. Tom:
    As quiet waters points out, even in this post of yours, you’re using the label
    against someone who does have scientific background. I can affirm that
    Connolley has a scientific background regarding climate, as his area of
    interest overlaps mine, so I’ve read his papers and we’ve had professional
    correspondence, going back well before blogs were around.

    Cursory searching your site for usages of ‘activist’ shows that it’s usually
    referring to scientists and scientific results. If repeating scientific
    results makes one an ‘activist’, you’re definitely using a very
    private definition.

    Since your own claimed usage of the term is one you don’t abide by,
    it’s really a very poor label. Really just a bit of namecalling against
    whomever says or does things you don’t like, which does explain your
    usage re. Connolley. The problem is not one of the label, whatever
    it is you use at the time, but the fact that whether you’re using
    warmist/activist/watermelon/fascist/SS/… it’s simply namecalling that
    could be text-replaced with the playground ‘doodyhead’ with no loss of

    Speaking of usage, it’s curious indeed that you, who are so concerned about
    the label ‘denier’, have no problem with Nitschke’s label ‘SS’.

    In other matters, since you’ve taken on the role of Ridley’s defender and
    explainer, how long does he have to fail to answer before you offer up
    a revised excuse (from the current ‘he’s busy with his new Lord post’)
    for his failure to respond? Is there any limit past which you’d conclude
    (tentatively, of course) that he’s not going to, or even that he hasn’t
    actually read the science to know whether it supports his claims or

    • Hi Robert

      Connelly acts like those who I include under the rubric ‘activists’ so I include him in. I chose activists as the least offensive term I could find. I asked you for a term that would differentiate Tim Lambert from Andrew Adams, for example, who I consider an exemplar both sides should aim at in behavior. I doubt if you’re actually suggesting ‘doodyheads’, which is fortunate as I might be tempted to label their opponents ‘howdyheads’ for symmetry’s sake.

      I will do what you did and examine my site for how I used the term activists and who I included and will report on the results. But I’m not sure you have read the site carefully, especially if you think I’ve taken on the role of Ridley’s defender.

      We’ll see if he comes back. If not, I’ll see what he continues to write about the issue. As for William’s use of SS, where is it? Was he referring to the website Skeptical Science? I’ll have a look at that as well.

      • Tom:

        Nitschke’s usages that I noticed were on 1/30 and 1/31. In at least one,
        he shows that he knows the usual abbreviation is SkS, but uses SS himself.
        Pretty obvious that what’s at hand is not merely a 1 character shorter
        abbreviation. Particularly with your lengthy note on ‘denier’.

        Your search for labels, and the fact that you ignore your own claims about
        what they mean, points to the purpose. Making ‘doodyhead’ entirely
        equivalent. ‘Lambert’ and ‘Adams’ would serve to distinguish between
        Tim Lambert and Andrew Adams when such a thing is needed, if you had
        no interest in adding some perjorative usage.

        In the discussion we had on Ridley’s 4th point, you pretty actively took
        up the role of defender of Ridley, protecting him from me, as you
        put it: “As someone who has been caught in this sort of a crossfire of
        competing requests for sourcing and calculations (even put in a very
        cordial tone, as by Robert), I want to raise a hand in Matt’s defense
        here.”, followed by you excusing him in other notes. In a later response
        of yours, you say “Well as I think you’re most probably correct I didn’t
        think you need defending. As I think Matt is approaching this from outside
        a strictly scientific approach (which I would also defend as his
        right–remember that I’m not a scientist either), and as I have disagreed
        with him on two of his essay points, I thought it appropriate to at
        least defend his approach.”

        If you’re going to call it a defense that you’re doing, it doesn’t seem unfair
        for me to use that term for it as well.

      • Hi Robert

        First, humanity does seem to have a need for collective nouns. I certainly do. Many have objected to the term ‘alarmist’, so I am actively seeking an alternative. I am seeking a way to group those who I believe damage the discourse, such as Connolley and Lambert, Secular Animist and dhogaza, from those who further it, such as Andrew Adams, Bart Verheggen and your own good self. I confess I am puzzled by your reaction to the term activist. What specifically do you find objectionable about it?

        I will chide Will if he chooses to use the initials of the website Skeptical Science without the sanitizing addition of the ‘k’ in future.

        I was defending Ridley in terms of blog process and its interference with human schedules, not his science. I would do so again. I am pleased that a prestigious writer responded to an unknown blogger commenting on his essay. I don’t think it is entirely likely that he will keep to a schedule and respond in the same way I do to comments here. I think it unfair to expect him to place this weblog and his reactions to it on the same level as the undoubted hoopla that goes with the territory of being asked to sit in the UK House of Lords. I will defend him again, if necessary, on those points.

        I will also defend his decision to approach this from outside the perspective of published science. He is not a scientist, but is a well-established commentator on policy issues and impacts. As it’s pretty much my schtick, too, it would be remarkable for me not to defend it. We need the science. But what we decide to do with the science is an additional subject, one which non-scientists can weigh in on.

        I am not defending the content of his essay. If you think I am I don’t believe you’re reading my posts with enough time.

      • Just to go a bit further than my previous comment, one of the central theses that have informed my view of the climate conversation is that a large group of environmentalists self-selected themselves as spokespersons for the climate change issue. As I’ve written in the past, I believe they grabbed the microphone away from scientists who were reluctant to step on the public stage and used the opportunity to advance an agenda that, while often informed by science, equally often went far beyond it. Early examples include Al Gore, a more recent one is Bill McKibben.

        The harm this did to both the debate and policy outcomes to date is hard to overestimate. Garbage statistics and over-hyped findings are not unknown in other fields. But for most of the past two decades they have been hyper-prevalent in this area.

        The sad fact is that people like Joe Romm and William Connolley do have scientific credentials. In my mind that makes their behavior worse, not better. And I say that despite having written in the past that Romm has without doubt the best overview of green technology developments anywhere and that Connolley can make surprisingly good sense when he chooses to. He just doesn’t choose to very often.

        The intrusion of professional communicators from the large environmental NGOs, with their ‘We know where you live,’ ‘No pressure’, polar bears falling in NYC and more recently the hyping of Xtreme Weather, all these are obstacles to intelligent debate. The fact that there are examples on the other side, such as Marc Morano and Monckton is no excuse.

        There is a difference between those interested in rational debate and the larger group of those who share many of your opinions. Not everybody on your side is your friend. Not everyone in opposition is your enemy.

  18. Tom,

    Any term is perjorative if used perjoratively. ‘activist’ becomes so from you as soon as you violate your own claimed meaning for it to include someone who don’t like under it, on the grounds that you don’t like him.

    Most of the rest of the two responses has nothing to do with what I wrote, which runs you afoul of the point you seemed to be agreeing with me regarding, over at my blog — that more progress will be made if you address the people present, and their points, rather than other people elsewhere. Your grudges against any number of other people is between you and them, not me.

    Commenters on science should know the science they’re commenting on. They don’t need to be, or have been, scientists themselves. But it is certainly relevant to ask that before they make decisions about what to do with the science, they know what was said. Though you argue in favor of decisions based on op-ed and press release, that’s not a point I’m ever going to agree with. Ridley, in 4, the one topic I looked at, misrepresented the science. He’s basing his policy decisions regarding what to do regarding the science on his misrepresentation. I find that problematic.

    As I’d expected, you broaden your defense of him. So be it. Yet, if policy is being made by someone who retreats from the possibility of learning what’s true in the science, I have to question the quality of that policy — regardless of whose ‘side’ he’s on.

    I’m the one person ‘on my side’. I speak for nobody else, and nobody else speaks for me. So it goes with science, at minimum though I accord that assumption to others as well. Who shares what opinions, I’m really not concerned with. Who lies about the science, or fails to understand the science and avoid learning better, I do care about. Rational discussion is not to be had when some in the conversation don’t know what they’re talking about and don’t want to learn about it.

    Note that I said discussion, not debate. If you want debate, of course you have to divide things in to two ‘sides’, which always winds up being the good guys (under whatever label) and the bad guys (ditto). I don’t find that helpful, myself:

    In assigning me a ‘side’, since you insist on that rather than dealing with individuals, consider this: The people you loathe so are all advocating policy changes on the basis of their concerns about climate change and its effects. You’ll be hard-pressed to find me advocating policies regarding climate change. The reason is straightforward — I don’t think the US will do anything material regarding climate change, or even routine weather (see the status of the US weather satellite program), for a generation more. Whether my ideas for policy are good or not is irrelevant, and discussing them would not lead to any progress.

    So I talk about the science instead. That doesn’t drive policy, obviously. Nor have much to do with policy. But there’s a lot of interesting science and math to talk about regarding climate. Insofar as there are people interested in that, it’s actively detrimental to talk about policy.

    (Ed. Note: Robert, I took the liberty of deleting two duplicate paragraphs in this comment as I think it’s important enough to address at length and I want other viewers to see it compactly. I hope that’s okay.)

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