Uncertain future of climate uncertainty

by Judith Curry

How believable are the IPCC’s continually increasing confidence levels?

Disconcerting learning on climate sensitivity and the uncertain future of uncertainty

Alexis Hannart, Michael Ghil, Jean-Louis Dufrwsne, Philippe Naveau

Abstract How will our estimates of climate uncertainty evolve in the coming years, as new learning is acquired and climate research makes further progress? As a tentative contribution to this question, we argue here that the future path of climate uncertainty may itself be quite uncertain, and that our uncertainty is actually prone to increase even though we learn more about the climate system. We term disconcerting learning this somewhat counter-intuitive process in which improved knowledge generates higher uncertainty. After recalling some definitions, this concept is connected with the related concept of negative learning. We illustrate disconcerting learning on several real-life examples and characterize mathematically certain general conditions for its occurrence. We show next that these conditions are met in the current state of our knowledge on climate sensitivity, and illustrate this situation based on an energy balance model of climate. We finally discuss the implications of these results on the development of adaptation and mitigation policy.

Published in Climatic Change, [link] to abstract.

The paper’s Discussion and Conclusions gives a good overview of their argument, excerpts:

Oppenheimer et al. (2008) introduced a probabilistic definition of learning in the context of scientific research on environmental problems. These authors showed that learning does not necessarily lead to truer beliefs, a situation they termed negative learning. We have extended this analysis here to show that learning does not necessarily lead to more certain beliefs either, a situation for which we introduced the term of disconcerting learning. Negative learning corresponds to an increase in PDF bias, disconcerting learning corresponds to an increase in PDF dispersion. We have shown that the latter differs from, and is not tied to, the occurrence of the former. In other words, learning may well result in a state of knowledge which is closer to the truth and yet more uncertain, cf. Fig. 1.

printWe have shown that this rather counter-intuitive situation typically arises when a surprising but inconclusive piece of evidence is found. We introduced  a probabilistic model based on reasonable assumptions about learning, and used it to confirm that disconcerting learning in general occurs as a result of surprising but inconclusive evidence at a particular step in the learning process. Furthermore, we narrowed in on this situation arising when the PDF that reflects the state of knowledge is asymmetric or has heavy tails. We have shown that the dispersion of the trajectories of uncertainty as learning occurs—i.e. the uncertainty on the uncertainty—is high when disconcerting learning is prone to happen.

Finally, because pronounced asymmetry appears to be a pervasive feature of the PDF of climate sensitivity in our current state of knowledge [AR4], climate uncertainty is thus prone to remain high or to increase—even if and as climate science makes steady progress—and thus its future trajectory is itself highly uncertain. 

At first, the news that substantial research efforts dedicated to improving our understanding of the climate system could potentially result in an increased uncertainty on the outcome of future climate change may sound rather discouraging. On the other hand, the present article also provides a rational justification for the fact that  constant or even increasing uncertainty is perfectly compatible with steady scientific progress and improved knowledge of the climate system. In other words, our results suggest that the uncertainty on climate sensitivity should not be considered as an appropriate metric to monitor progress in climate science, as has sometimes been suggested.

Indeed, the initial increase of uncertainty is caused by the inconclusive nature of the surprising evidence. As more reassuring evidence confirms what was at first a surprise, uncertainty will eventually decrease. 

JC comments:

The pause in global surface temperature anomalies for the past 15+ years is arguably an example of negative disconcerting learning.  Well the IPCC doesn’t seem to have learned anything yet from this and are not yet disconcerted since they expect the warming to resume imminently.  However outside the context of the IPCC, negative disconcerting learning is taking place, as scientists put forward alternative hypotheses for testing.  So the pause is arguably a good thing for climate science.

However, the IPCC feels compelled to continually increase confidence levels (now to 95% on the 20th century attribution), despite the reality of the situation whereby negative disconcerting learning is taking place and previous assumptions are being challenged.  Acknowledgement of negative learning, even disconcerting learning, seems important to avoid this senseless march towards increasing confidence as the model projections and observations diverge.

The paper also has a section on policy implications of negative and disconcerting learning, in context of optimal decision making.  In light of the perspective presented by this paper, Roger Pielke has a tweet today that sums it up perfectly:

An alternative to calling for accepting science as starting point would be to focus on policies robust to scientific debates.

191 responses to “Uncertain future of climate uncertainty

  1. Difference between a meteorologist and an AGW Alarmist:

    A weatherman says the 2013-4 winter in Europe will not be a mild one and maybe as cold as one that only comes along every 50 years.

    The Alarmist says a cold European winter is proof of AGW.

  2. The excerpt refers to asymmetry and heavy tail. That’s important for the questions related to the risk of really serious outcomes. It’s not at all as relevant for the intrpretation of the hiatus.

    • The fat tail has been chopped off.

      • Perhaps.

        The message of this paper is, however, that it may come back.

      • More likely get thiner and shorter. After all, ECS is being reduced and we have next to no understanding of the damage function. Once we do get to know these with precision they will have a very narrow range at an y given starting position (such as the conditions on the planet now). So, clearly the trend is towards a very short skinny tail.

      • Technically an extreme case of this problem is provided by a PDF, that has no finite expectation value due to the fat tail. Based on any finite amount of observations a finite estimate is found for the expectation value, but additional observations lead to higher and higher estimates without an upper limit.

      • Pekka, I am making a distinction between the pdf of our understanding of damage function, versus the pdf of the actual damage function if we could measure it precisely.

        Eventually, our knowledge of the actual damage function will improve and the pdf of our knowledge of it will approach the pdf of the actual damage function – i.e. a narrow pdf with a short thin tail.

      • Yes, it may get thinner and shorter, but then we don’t have the case discussed in the paper.

      • See my last comment; it was posted out of sequence for some strange reason.

      • Does this graph make my tail look fat?

      • Peter and Pekka

        The fat tail has been chopped off.

        The message of this paper is, however, that it may come back.

        (Like the head of the hydra (which, fortunately, was an imaginary beast.)

        But it appears that latest data point toward Peter being right on this.

        ”It’s increasingly difficult to reconcile a high climate sensitivity (say over 4C) with the observational evidence for the planetary energy balance over the industrial era.”

        But, of course, we cannot be “certain” of anything, can we?


      • Manacker,

        Thanks for the added sanity. I’ll add my sensible comment and expand on what I meant.

        Climate sensitivity and the range has changed little over the past 25 years, until AR5. Now, at last, IPCC has chopped off the long tail. No longer do they believe it could extend out to 12C and 20C as some climatge scientists had been saying previously. AR5 now says ECS is highly unlikely to be more than 6C (or words to that effect). So, they’ve chopped it off.

        But, my understanding (perhaos misunderstanding), is that this is not the range of climate sensitivity, but rather it is the range of our very imprecise, inaccurate, low confidence estimates of what ECS might be. When we eventually do determine ECS with high precision (for current conditions) it will probably have a small range, e.g. +/- 0.1C. So If the central estimate is 2.0, the tail may extend to 2.1C not 6C.

      • My view is that understanding uncertainties is essential when climate science is used in support of decision making. As far as I can understand I agree this far with Judith, and perhaps also with many skeptics.

        Where I’m not happy with most of discussion of uncertainties on this site is in the choice of the type of uncertainties that get most emphasis. To me the two most essential classes of uncertainty are:

        1) The uncertainties in likelihoods and severities of worst credible outcomes.

        2) The uncertainties in the usefulness and costs (including unforeseen consequences) of proposed mitigation measures and policies.

        3) The issues related to the political realism and compatibility with democratic decision making of the proposed mitigation measures and policies.

        Issues like the hiatus are almost irrelevant for the above, including the first point. Most of the discussion of uncertainties here seems to concentrate on details that are of little significance in my judgment, although the points 2) and 3) have been discussed by some (I would include Peter in this group).

      • Pekka,

        Your comment is such a pile of motherhood, or pollie speak, that I expect few if anyone could disagree with you. But what on Earth are you saying? What do you agree with and what do you disagree with that I said in my comment?

        IMO, the greatest uncertainties for policy analysis, development and implementation are:

        1. uncertainties about how much warming (or reduced cooling) in future years;

        2. uncertainties about what are the costs and benefits of warming or cooling (e.g. costs and benefits per degree of warming or cooling)

        3. uncertainties about how much GHG emissions will be emitted

        4. Uncertainties about the likelihood that the chosen policy responses will be successful and will last ling enough to achieve their objectives.

        What’s you list, what do you agree with and disagree with. Please be specific.

      • Peter Lang,

        I think I’m learning to speak Pekka a bit, though I am still a novice. But I think his uncertainties 1, 2 and 3 are the same as your 1, 2 and 4.

      • GaryM,

        Thanks for the translation. I’ll look forward to Pekka confirming or denying and correcting your translation and hopefully elaborating on what he means (a lot).

      • My first covers the same issues as Peter’s 1) and 2) combined but is not exactly the same as I emphasize the high end of the estimates, while Peter seems to be neutral on that emphasis.

        Peter’s 3) is affected by the chosen policies and that part is related to his 4) as well as my 2) and 3), but the question of the development of emissions even without active mitigation policies is an interesting issue that I didn’t mention. It could be considered to be included in my 1), but perhaps it’s worth being listed separately.

        My 2) is essentially the same as Peter’s 4). My 3) goes further in the uncertain questions of politics.

    • Chief Hydrologist

      Here is a pre-pub version – although I am surprised that I learn little more than with the excerpts. – http://www.lsce.ipsl.fr/Phocea/file.php?class=pisp&reload=1367335502&file=philippe.naveau/files/109/Hannart13.pdf

      Disconcerting learning arises from surprising – and inconclusive – observations. Which are said to be rare in the paper but are probably not all that rare at all in climate. So the question reduces to the capacity of climate to surprise us – something of a significant potential. Indeed inevitable.

  3. We term disconcerting learning this somewhat counter-intuitive process in which improved knowledge generates higher uncertainty.

    Things seem black and white to those who don’t know much about them.

  4. “The more you know, the less you understand” (anon)

  5. Why all the contorted language? Negative learning? Really?

    Lets try something like this – The IPCC have wilfully ignored any evidence that contradicts their political aims.

    There no contortion of the language required.

    • +1000

    • Good point: “The more I learn, the more I learn how little I know” (Socrates) becomes–e.g.:

      Counter-intuitively the more I learn I am disconcerted and tentatively clouded by an increasing estimate of my actual uncertainty to such extent that improving my knowledge requires considerable negative learning or understanding I’m an idiot for abandoning the scientific method.

    • Steven Mosher

      it’s rather common. sometimes the more you learn the more you realize there is to learn. Whereas, somebody who doesnt realize that there are unknown unknowns will be certain that the IPCC is wrong.

      • “Whereas, somebody who doesnt realize that there are unknown unknowns will be certain that the IPCC is wrong.”

        or right.


      • “somebody who doesnt realize that there are unknown unknowns will be certain that the IPCC is wrong”

        That makes absolutely no sense at all. And of that I am certain.

      • Steven Mosher

        I’ll put the same thought this way.
        If you know the IPCC is wrong, you’re ignorant of your ignorance.

        I hope that helps.

        put another way. be skeptical of your skepticism.

        or, if you think you are certain, you’re probably wrong, at the very least you’re probably wrong about being certain or misusing the word

      • Yes, all of those make sense, and I agree with them all. They do not represent the same thought as your original comment, even if that was your intent.

        “[S]omebody who doesn’t realize that there are unknown unknowns” would be likely to agree with the IPCC and it’s inflated clams of certainty, not likely to be certain the IPCC was wrong. A little unconscious projection there I think.

      • Make that “subconscious” not unconscious, as I assume you were awake while typing.

      • Root vegetables everywhere applaud your logic.

      • Rutabagas root for straightforward policy routes.

      • Steven Mosher

        Whereas, somebody who doesnt realize that there are unknown unknowns will be certain that the IPCC is wrong.

        Not necessarily, Mosh.

        This “somebody” (IPCC itself?) could also be (more) certain that the IPCC is right.

        Or, as in my case:

        Somebody who realizes that there are unknown unknowns will be less certain that the IPCC is right.


  6. Steven Mosher

    “An alternative to calling for accepting science as starting point would be to focus on policies robust to scientific debates.”


    • If that’s the case, why is there so much debate between people who say we’ve got to quadruple (or whatever) the cost of fossil-carbon energy, and people who say there’s no reason to do anything? I don’t see much interest in no-regrets approaches, or even low-regrets approaches. I certainly don’t see much interest in exploring the criteria for solutions.

    • I read that, and thought yes, that makes perfect sense.

      Then I started to think about it in terms of climate science and policy, and wondered if it meant (in practice) anything more than policies that anger extremists on both sides of the debate. Sitting on the fence in other words..

      In the UK, we often hear policies being justified on the basis that they’ve upset almost everyone and must therefore be the right thing. It never convinces me.

      I know that many consider alarmism as the only way to goad an otherwise reluctant set of politicians and bureaucrats into action. Perhaps, instead of pursuing his conspiracist ideation theme Lewandowsky might be better employed in examining the successfulness and effectiveness of alarmism in determining government policy…

      • “The only thing we have to fear is fear itself.”

      • “Perhaps, instead of pursuing his conspiracist ideation theme Lewandowsky might be better employed in examining the successfulness and effectiveness of alarmism in determining government policy…”

        No funding, no notoriety, so no touchee …

  7. I think the IPCC should get fitted with one of those back up beepers like on the garbage trucks.

  8. “..no contortion of the language required”

    Of course academics do this all the time. “Surprises” is too simple, so we come up with “disconcerting learning.” The more they belabor the obvious the more they feel the need to dress it up. So is this the central point? “In other words, learning may well result in a state of knowledge which is closer to the truth and yet more uncertain.” Is there any thinking person over the age of 18 who doesn’t know this?

    • This begs the question of how many thinking people there are.

    • A surprise consists of an unanticipated development, requiring a new POV to accommodate. That new POV will often include acknowledgement of the existence of variability and factors not previously known or acknowledged. Not only will those require some or much additional exploration to characterize, it may be that some are “chaotic” wild variables that make prediction of more than trivially brief periods computationally unachievable, or “hard”.
      One variety of this is the demotion of some independent variables to insignificance, or narrowing their reach to special cases, “all other things being equal”, with no real prospect of other things ever being equal, and with non-linear interactions of non-linear relevance (boundary conditions).
      Despite the IPCC’s bluster, climate is the poster child for such scenarios. It is not just bad luck that made its choice of “forcing variable” to rule them all a pure fantasy.

  9. Roger Pielke Jr’s tweet:

    An alternative to calling for accepting science as starting point would be to focus on policies robust to scientific debates.

    Right on. And the policy that is most robust to scientific debates and to what ever happens is free markets, free trade, small government.

  10. (note: sorry Dr. Curry, I seem to have posted this comment to a much earlier thread on CS, you can remove it there if deemed necessary)

    If the adjustments are not correct then the CS fades to nearly nothing. Here is a comment I just made on another site. All of this hinges not on the actual natural variations in the temperatures but solely on the adjustments made to the temperature datasets.

    I have decided to share this peculiar view of current climate science as I have recently stumbled upon, though I’m sure this has been raised though before, in pieces and and I have never it all together in one simple comment or post, but I have seen the traces but I never seemed to get the full thrust of what this shows.

    First look at some various plots of the adjustments made to the various temperature datasets gathered over the last few years, they are all close to linear in the years past 1940 and will be dealt with as such, linear form start year to now. The red lines added were just for myself to get a close average rate it seems all datasets are being adjusted upward (artificially warmer) over time. Why it started right at 1940, I don’t know why. Quite honestly I don’t really care here how many peer-reviewed papers created the adjustments, just going to ignore that topic here.

    Can artificial adjustments actually warm or cool the earth? Of course not, so they will be removed.

    USHCN: http://i43.tinypic.com/s3m3wk.png
    GISS: http://i39.tinypic.com/1zfrn1l.png
    NOAA: http://i40.tinypic.com/2uy2bg4.png

    Here is a plot of the latest accepted dataset after removing the +0.75°C/century (0.000625 °C/mo) artificial adjustments from the dataset starting in 1940.
    or with less smoothing:

    Any adjustments before 1940 were ignored but you may want to find actual datasets of these adjustments and get very precise but the changes you would see prior to 1940 to that plot are going to be very small. This is just a rough overview but you should see the point.

    Put on your thinking hat and you decide what you gather from this set of data. I seem to see that all of the rise of temperature over and above the natural variance (of about ±0.25°C) is completely in the upward adjustments, without the adjustments it appears perfectly normal and symmetric the way I have always assumed nature to be, vacillations about the mean. I for one have the opinion that 1997-1998 was no warmer that the late 1930’s temperatures after information from elders living through the dust bowl years.

    Read Callender’s 1938 paper, especially the comments from Society members at the end, and you just may see what I see is so amusing, seems nothing has changed at all, it was right at the peak of temperatures in 1938 also:

    This was such a quick and simple look at that data but it sure left an impression and it might leave such on others who get confused by the complexities involved in the temperature series plots.

    Some will say this is not proper science, true, but it is proper reality to look at what it was before the adjustments.

    • Wayne, Are you a conspiracist in suggesting that data has been tampered with?

      If it was actually tampered with, one couldn’t get as good agreement as one can see with the various data sets. The following link is to a semantic web server which does a decomposition of the global warming signal using my SALT model:
      Select “Match temperature with model” and enter a 60 month lag. Look at the agreement and then look at the correlation coefficient.

      I saw Prof. Vaughan Pratt around these parts recently. This is a long-in-coming substantiation of his sawtooth model.

      • Said nothing of tampering, just interesting what it looks like without, that you never see. Are the adjustments correct and justified? Many say no and see major problems, many say yes, and to me it still needs a very close look at the adjustment assumptions made and particularly the homogenization process that I understand is the majority of it. I have little time to go into it in that depth but others do, maybe they will.

      • Pratts’s model was pretty much dead on the vine since he assumed away the sawtooth. Most of the saw tooth was due to NH cooling that was out of balance with SH cooling which appears to be due to an imbalance in Volcanic forcing. You don’t have to wait for Vaughan’s model or yours for that matter to know they have failed.


        Since the Crowley and Unterman 2012/13 paper provide a better but not quite there yet estimate of volcanic aerosols by hemisphere and we know that the land temperature measures “amplify” global impacts, Pratt’s method. is likely to grossly over estimate sensitivity.

        It was pretty though – down to millikelvins of wrongness.

      • Pratt’s model is phenomenological and heuristic and only lacked a mapping to basis functions which is what my model provides.

      • Webster, dLOD not a basic function. It is a response to various combined functions. When you “remove” solar and volcanic which are influences on dLOD you are still leaving tidal/internal mixing which cause changing rates of recovery and assuming that is nothing but CO2. You have a nice little “weather” fit as long as you stay close to your baseline period.

        Now extend your model to 1750. Oops! ya can’t because you are using data limited to 1880. You have successfully overfit a smoothed section of temperature data. Congratulations, you have earned the V. Pratt overfitting of the month award.

  11. John Carpenter

    Not to be OT, but Is it me, or is the ‘recent comments’ thing not working?

    • Seems it is not working on any of the WordPress sites right now.

      • Shucks, I thought we had all gotten a Micro-Agression time out.

      • According to a WordPress support blog:

        Hello all.

        There have been reports of comments not appearing in the “recent comments” widget box. We are aware of the problem and are working on it.

        There are also reports of the comments widget ignoring the display limitation. That is being looked into as well.

        My apologies for any trouble. Please subscribe to this thread for updates on the situation.

        I noticed that for a while there were 15 comments displayed here at climate etc., rather than the usual 10 (which I thought was GREAT), then it stopped showing comments at all.

      • Hah, Cap’n, I was sure I was the only one with a fish on the line.

    • I’m pretty sure it’s the “consensus police” trying to keep Peter Lang from getting his earth-changing comments out to the public.

  12. More French ruminations on the difficulties of ruminating? Just when you thought it was safe to go back into the Deux Magots!

    Judging by this latest tangle of gaseous abstractions masquerading as a “study”, I’m wondering if scientists should not do be doing less, rather than more, of what they call “communication”. As Sam Johnson said of a dog walking on its hind legs, it is not done well, but you are surprised to find it done at all.

  13. 1 Introduction and motivation

    Strong scientific consensus prevails over the fact that Earth’s climate is currently warming and will be warming further over the coming decades…

    Sounds like a lot the authors actually know! Long live AR4!

  14. Morley Sutter

    What happened to interpretation of data rather than just predictions as a method of doing science?

    • John Carpenter

      If you think you know how to interpret observable data correctly then you make a model/theory to describe it. To test it, you make predictions based on your model/theory. If your predictions agree with new observations, you gain confidence in your model/theory.

      Making predictions is not a method of doing science, it is part of testing your knowledge. Interpreting data does not test your knowledge. Without testing your knowledge, it’s hard to say whether you know you have interpreted the data correctly. So it is important to make predictions, otherwise you end up fooling yourself into knowing something that may not be correct.

    • Keep it simple, honest and then argue! Sounds too simple? You may be on to something?

  15. Where would the Michelson–Morley discoveries fit into this?

    • Those guys had a well-defined hypothesis to test. Climate models aren’t some sort of clean-cut hypothesis.

      When Einstein formulated relativity, he brushed aside dust on one facet of the beautiful diamond that is the Universe.

      Climate modelers take that diamond, smash it, then glue together the pieces with Crazy Glue, slapdash parameters, and some approximations to make up for the lack of knowledge and computing power.

  16. Pardon me for being a party pooper, but isn’t this bloody obvious, and haven’t we discussed this before, way back when Lewandowsky was peddling the “more uncertainty identical to higher variance” canard? Higher variance of an outcome isn’t synonomous with less information. Suppose A, B and C comprise a mutually exclusive and exhaustive list of events, with associated outcomes x(A) > x(B) > x(C). Now information comes along that rules out event B but not A or C. Typically in this situation the variance will rise because the middle outcome has been ruled out. So what’s the big deal? I looked at the Chen et al. paper they refer to, and it seems it is saying nothing more than this.

    There are very few routes by which preferences between policies can be reduced to a mean-variance analysis anyway. The whole point of Rothschild and Stiglitz’s (1971) classic “Increasing Risk I: A Definition” was to show that increasing variance was the odd man out of several alternative definitions of “increasing risk.” So to me, this sounds like an answer looking for a problem that was banished a long time ago (or should have been).

  17. Or, these people could be completely and totally wrong and the PDF could tighten up as we learn about the REAL drivers of climate. I would say the probability of these authors being correct is 0.2.

    • This is the way to look at uncertainty in the ECS 1.5 to 4.5C range:

      The bottom range of 1.5C is the TCR based on observational evidence of just SST data.
      The TCR=3C for Land is a baseline value for ECS as this is not expected to decrease with time.
      The TCR of 2C is for Global temperatures and is a pro-rated mix of SST and Land data.

      The upper range above 3C is unknown because those values are not based on observational evidence but on Paleo data where the slow positive feedbacks were given time to evolve.

      The experimental evidence for CO2 TCR can be evaluated using my model here:

  18. If “climate science” was bona fide, instead of a collage of conjectures, there would far more talk about verifiable physics and far less about the uncertainty of unverified ideas.

  19. So ignorance actually might be more blissful…

  20. I once tried to explain the difference between humility and vanity to my son. I said it is like walking into a building that has two doors. Each of those doors leads to a room with two more doors. The further you go, the more doors you open, the more rooms you see. After opening many doors, and seeing what is in many rooms, you stop and consider what you have seen.

    I told him a humble man thinks of all the doors he has opened and rooms he has seen, and looks forward and is humbled by the knowledge he has learned because it gives him a hint of what he still does not know. It gives him an idea of how vast the building is, and how much more he has to see. The more he learns, the more humble he becomes.

    The vain man thinks of how many doors he has opened and rooms he has seen, and looks back, marveling at how much he has seen. It gives him the idea that he knows more about the building now than he ever has before. The more he learns, the more vain he becomes.

    An inflated level of certainty is nothing more than the symptom of inflated vanity.

    • Ah, so that explains why young people are so much wiser than older people. :)

    • Correction:

      Ah, so that explains why young people are so much wiser than people who have opened more doors. :)

      • Peter Lang,

        That is early onset vanity. It is curable. The older you are, the less responsive it is to treatment.

      • These days they teach narcissism in the schools. They call it “self esteem”. I don’t have a whole lot of hope that any of this juvenile onset narcissism is any more treatable than juvenile onset diabetes.

        Maybe getting kicked out of mom’s basements might help.

      • “Maybe getting kicked out of mom’s basements might help.”

        Somebody alert Joshua. This has him written all over it.


      • I miss Max_OK. But I’m getting better.

    • reminds me of a question and answer session I had with my 10 year old

      Q. I have a house with three rooms A B and C. The temperature in room A is 10C, in room B is 12C and in C is 14C. So what is the average temperature of my house?

      A. 10+12+14=36 – divide by 3 = 12c

      Q. which is the warmest room?

      A. Room C. Duh

      Q. which contains the most heat energy?

      A. can’t answer without knowing the size of the room and its enthalpy Jackass

  21. Every day, I assume that the probability of particular events is 100%. Not 99.999…, but 100.

    I assume, rightly or wrongly, that I will still be alive at dinnertime. My wife also makes this assumption, and we prepare dinner for two.

    When I board an aeroplane, if the pilot announced that there was a 99% chance that we would land at our destination intact, I would immediately deplane. I expect my brakes and steering not to fail while driving down steep mountain roads, and so on.

    There is no guarantee that the Sun will not suffer a catastrophic disintegration within the next day, year, century or whatever. I choose to assume it won’t, and so far I am still content with life.

    The future is unknowable, as far as I am aware. Talk of the likelihood of this, and the probability of that, is oft times meaningless blather. As far as weather, (and hence climate, merely being the average of weather), goes, what use is a prediction of a 80 or 90 percent chance of rain? Should I take an umbrella or not? Would I be worse off tossing a coin?

    I am happy enough to accept “expert” assumptions on occasion, in instances where I assume that it is my interest to do so.

    However, to date, the “model outputs”, “projections”, “scenarios”, or other semantic workarounds to avoid being ranked alongside your friendly neighbourhood fortune teller, have proved to be completely useless. That is, having no practical utility of any type, apart from demonstrating the incompetence of the provider of such nonsense.

    Possibly somebody can point to an instance of changing their lifestyle in a positive fashion as a result of a climatological forecast, and for no other reason. I live in hope.

    Live well and prosper,

    Mike Flynn.

    • “The future is unknowable, as far as I am aware.” A major reason for my not wishing to expensively remodel our economy on the basis of long-term computer-modelled projections.

    • In the UK we are blessed with the prognostications of the Met Office and it is very helpful. If they say the next 3 months is going to be unusually dry, we prepare for floods. If they predict a mild winter, we get the snow gear dusted off. Barbecue summer, break out the umbrellas. Not quite 100% but I think 95% of experts would agree that most of the likely probability is most certainly probably wrong (or right).

  22. The IPCC were able to increase their certainty mostly by lowering their lower end sensitivity to 1.5 C per doubling. This also brings in most of the skeptics to the IPCC view that CO2, even with low sensitivity barely above no-feedback levels, can now by itself account for the temperature rise since 1950. The “pause” also helped this statistic by reducing the average warming rate. So the increase in certainty is no surprise. Just broaden your error bars, and you can be more certain that the data fits the theory.

    • As mentioned above, we still await the return of Recent Comments that appears to be a wordpress problem. I live by that on here. Tough going without it.

    • Broadening the error bars is not relevant to the IPCC’s statement regarding past warming.

      But maybe it was just an honest mistake?


      • I tried to understand what Roy was getting at, but I think he was just fooling around. What would 50% look like in his theory?

    • John Carpenter

      Widening error bars is lowering the bar of knowledge. It is an admission you know less about the process rather than more. You widen the error to lower the probability of being wrong, but it is inversely proportional to your knowledge about the system or process. You know less about the true position. I can widen the error bars to become 99% certain, but it also means I know even less about true position. So you may be able to claim higher certainty that the true position lies between wider error bars… Duh… but you also own less knowledge…. Negative learning?

      • I think you reflect what I was getting at. Why do people complain about the IPCC now having more certainty in that case? They don’t have more certainty when the error bars are wider, but the “pause” helped their certainty too, which I find ironic.

      • More amusing irony to consider how the pause extending longer will continue to increase the IPCC’s certainty. Heading for 100% certainty and in a venue near you!

      • John Carpenter

        “Why do people complain about the IPCC now having more certainty in that case?”

        Jim D, I don’t think there would be as much to complain about if that was how it was presented. However, the IPCC presented, rather arbitrarily as far as I can tell, greater certainty but forgot to mention that it came at the expense of not knowing anything better than before. What has been promoted is more certainty. The public will understand that as better knowledge. But if 95% certainty was achieved by just widening the error, then the IPCC is playing a bit of deception with the public by not also acknowledging the understanding of our climate system has been diminished. If the idea that widening the error bar range was how we went from 90 to 95% confidence, in reality then we know less than before. Where was that in the news?

    • Jim D

      Yep. IPCC shrewdly lowered “their lower end sensitivity to 1.5C per doubling” without letting it affect the mean estimate.

      What happened it actual fact was that several new independent (at least partially) observation-based studies showed that IPCC’s previous estimate was exaggerated by around 2:1.

      But instead of reducing its model-predicted range significantly to incorporate this new information, IPCC simply lowered the low end of the range and kept the mean estimate at around the same level, while claiming greater “certainty”.

      The old shell game at work here, Jim.

      Has nothing to do with science.


  23. JC: The more we learn, the more principles we are obliged to question. A ‘longer life’ implies a ‘longer list’ for inquiry. ;)

    Can the IPCC be educated on this principle? No! The group has realised that its obligation is directed by the ‘mandate’ set out by the UN.

    Best regards, Ray Dart.

  24. The PDO was discovered several years after the IPCC’s FAR yet we’re expected to accept that they were able to reliably identify and extract the AGW signal from the noise of natural variability. Ummm….

  25. William McClenney

    We are left to compare and contrast the following:




    “We show how the prevailing majority opinion in a population can be rapidly reversed by a small fraction p of randomly distributed committed agents who consistently proselytize the opposing opinion and are immune to influence. Specifically, we show that when the committed fraction grows beyond a critical value pc≈10%, there is a dramatic decrease in the time, Tc, taken for the entire population to adopt the committed opinion.”

    I mean no offense, but the question almost asks itself….

    Are you part of the 10% or the 90%? If so, not, or other, why?

    • “…we show that when the committed fraction grows beyond a critical value pc≈10%, there is a dramatic decrease in the time, Tc, taken for the entire population to adopt the committed opinion.”

      Ahh the certainty of the social “sciences”.

      But forget the certainty, and claimed precision here. Is it really news to anyone that public opinion can be, and often is, dramatically changed by a small group of committed activists?

      This is the whole reason for the concept of a republic. Which if I recall my high school history, is a concept that even predates Twitter.

      • .Um, those authors list their fields as computer science, math and physics. Whatever they are, they ain’t social “anythings” Don’t blame us for the Econophysics GaryM, I swear we didn’t do it.

      • Gary M, when you translate to common English – and reduce the socio-sciency mysticism to the dreary commonplaces of which it is made – the text loses all glamour. Where would a Pachauri romance novel be without all the cloying wordsmithery?

        Give bloat a chance!

      • Charabia and cloying wordsmithery. Worms lie rich on the ground this morning.

      • moso, your post reminds me of John Lennon’s campaign to reduce English baked bean consumption, with his song “Give peas a chance!”

      • Kim,

        Excellent! Where did you find “charabia”. I dips me lid!

        Live well and prosper,

        Mike Flynn – who has been known to over-imbibe. Apologies to all! I may regret this in the morning. Who gives a toss?

      • > Where did you find “charabia”.

        In Volovent’s comment, perhaps.


        I thought Michael Ghil was in the Denizens’ acceptable social network.

        Oh, well.

      • Oh, yes, hat tip to Volauvent. I tried it earlier, but the wind blew it away.

      • Willard,

        Thanks. My only excuse is that my perception was effected by the affluence of incohol.

        Apology tendered, to Volauvent.

        Live well and prosper.

        Mike Flynn

    • We live in the age of the pressure group and none of them have any popular mandate. You name it, there are some righteous citizens prepared to spill blood in the name of protecting it. The trouble is that the interests of the citizenry at large is demoted to at least second place and very often well behind the interests of the non-differentiated tree frog, the multispined flying barn rodent and the lesser spotted wart greebler.

  26. “How believable are the IPCC’s continually increasing confidence levels?”

    Probably more than Obamacare.

    And more people have signed up to live on Mars,
    than signed up for Obamacare.
    linked from:
    “SO IT LOOKS LIKE more people have applied to live on Mars than have signed up for ObamaCare so far.”

  27. William McClenney

    JC. You pose an eminently reasonable question. Allow, for a moment, that the IPCCs prognosticastions of future climate are correct. How much longer than half a precession cycle length does this augment the Holocene?

    Which is a far more imminent question………

    • I just love it when ‘imminent’, ’eminent’, and ‘immanent’ can all be interchangeably used.

  28. Judith,

    Uncertain future of climate uncertainty

    Very good. You managed to get the uncertain(ty) word in twice in a short phrase.

    This is an an example of why Joe Romm has described you as a confusionist and why he used the phrase ” Judith Curry abandons science” which, in the previous posting, you took to be an attack on your scientific work..

    You can check with him yourself , if you like, but I would suggest he’s not disagreeing with anything you’ve written as a peer reviewed work except perhaps in the normal way that scientific disagreements might arise. He’s certainly disagreeing with these sort of comments though.

    • Peter, I’m certain there is no better way than Judy’s to convey that idea.

      Joe? Paid Propagandist? We wish to interrupt your reverie.

    • tempterrain

      Joe Romm is “certain”

      Judith is less so

      Which one is a scientist?

      Think about it a bit before you answer.


    • Max,

      No it’s not correct to say Joe Romm is certain. The extent of the uncertainties is discussed at length in all IPCC reports. It could well be that Judith thinks the extents need to be widened and that’s a perfectly valid scientific view of course.

      What’s not a valid view, and this is the point of Joe Romm’s argument, is to use the agreed uncertainty to give the take home message that:

      That’s confusionism.

      • “scientists-aren’t-sure-of-the-extents-of-the-problem-therefore-we-should-just-ignore-it-until-they-are.”

        Can we get a cite for that quote? If not, I may not be a Joe Romm (thank God), but I certainly disagree with that sort of comment.

      • Let’s work on that. I think scientists-can’t-demonstrate-that-there-is-a-problem-therefore-we-should-shouldn’t-‘solve’-a-non-problem-until-they-can fits a bit better.

    • GaryM,

      Of course Judith is savvy enough to not spell out her message in the same stark terms I used.

      But, all the same, that’s the implication of what she’s saying. That’s why she’s the darling of the skeptic/deniers. Would she have been invited on to the Republican climate team if she’d argued that uncertainty works both ways? ie It doesn’t just mean that the adverse effects of CO2 accumulation could be less than predicted. It also means they could be worse.

      • tt,

        That’s simply not true. Dr. Curry can certainly defend herself if she chooses, but she regularly advocates additional research, adaptation, improved models for localized climate effects, and other CO2 related “no regrets” policies. That may not be the full blown decarbonization that you advocate, but it is not nothing. And it is dishonest of you to claim that it is.

      • As for the Republicans calling her to testify, I often think she needs reminding that it is only conservative policy makers who are willing to listen to her so far. Her disdain for “conservatives” is not on your level by any means, but she is no fan.

        And the claim that the fact that the Republicans called her as a witness is evidence that she advocates “just ignore it” as climate policy, is as dishonest as the faux quote.

      • tempterrain:

        “It doesn’t just mean that the adverse effects of CO2 accumulation could be less than predicted. It also means they could be worse.”

        If there is high sensitivity to CO2 then we’d draw uncertainty error bars around that. If there is lower sensitivity to CO2 we could also draw error bars around that lower value.

        Now which is the right one to use?

        I might say that knowing less about what the sensitivity is would argue to keep it at the lower value. If we aren’t sure what something does, shouldn’t we tend to assume it does less as compared to more?

      • Serendipity rears its head. Checking the latest comments list, I saw a spam bot post on an old thread”


        The second paragraph of which led to another thread:


        Re-read the main post there and tell me Dr. Curry is a clone of congressional Republicans.

      • The second link should be:


        Damn my Republican brain.

      • ….. she regularly advocates additional research additional research, adaptation, improved models for localized climate effects, and other CO2 related “no regrets” policies

        That’s like a doctor advocating the taking of an aspirin by a patient with a broken leg, and then claiming they aren’t in favour of totally ignoring the problem!

      • An aspirin for a broken leg. Great analogy, as long as the patient is currently doing wind sprints, and the last 15 broken legs the doctor diagnosed…weren’t.

  29. Anyone

    All the most ‘recent comments’ on the right hand side of the screen just above ‘recent posts’ have disappeared sd I have no idea who is currently talking to who.

    Is this just my computer? If so, has anyone any suggestions on how to retrieve the ‘recent’ comments facility?



    • It happenned before… It will be fixed probably.

      • Edim, r – u – kim ? )

        Re long range forecasts and certainty (?)

        Black swan, ebony gleaming,
        Gliding artlessly on
        A mirrored lake, unaware
        That you’re an oddity exposed
        By northern orni-thol-ogists.
        Glossy bird, you’d be surprised
        To learn you are compared
        To Hume’s thanksgiving turkey,
        Symbol of an out-liar event,
        The single observation that exposes
        How fragile is our human knowledge.
        Black swan, you have become
        A symbol too –
        So much more
        Than black bird – you.

      • Beth, excellent. But Edim is Edim. To differentiate the two, try “cheese-Japanese” – or “Edam-Kim’ono.” Not to be confused with Yoko.

      • Thx Faustino. Oh I wonder about mysterious Kim ….
        The imagination plays trix. One time I associated Kim
        with the author of ‘The Remains of the Day.’ (The
        chapter on banter, oh so witty, oh so kim-like.)

      • Well, part of me is, it sims.

  30. Tony,
    The problem is not in your receiver but is a wordpress problem,
    see above a comment by Jim D
    Beth the serf.

    • Beth

      Thanks. Co2 has edged above 400ppm. Presumably the problem is connected with that? If only we’d listened…

      • Tony, solution earlier from AK: You could use the comment feed. Refresh it every once in a while, and use right-click/open in a new tab to open comments you want to see the context to.

        You can keep two tabs open until the problem is resolved. Apparently it is affecting all WP sites.

      • Faustino

        Thanks for the tip, but who can I sue for the distress and inconvenience caused?


      • Tony, if you’ve been paying attention, you’ll know that it is your own reaction that is the cause of your suffering, not the proximate external cause. Shame on you.

      • How can he pay attention without a list of comments?

      • Oh, and BTW, Faustino, you’re welcome. Always a pleasure to get to show off.

  31. I am French and it is a shame for me that such a stupidity is published by French people; the fact that sometimes the more you study the more you discover previous unknown things does not need this pseudo bayaisian charabia.
    The problem is that they divide the uncertainty in 3 parts: scenarii, natural variability, anf GHG; of course, you can’t separate the two latest ones; (they get rid of natural variability in saying “it will vanish !” ) We know that the calculation of the GHG sensitivity is partly “validated” from the passed data, so it is dependant of the natural variability.
    And to consider that the “pause” is a case of disconcerting learnig is ridiculous as we got the same in the years 70s .
    For me it is just a tentative of “soft landing” to save furher funds and try to disconnect science from policy decisions; but it is too late, due to the bad behaviour of few “scientists”, it is impossible to go back. .

  32. Tomas Milanovic

    (a bit off topic)
    I have sent you a mail for Marcia concerning the stadium wave.
    As I didn’t receive a confirmation yet, I wonder if it arrived correctly.
    Could you check your mail box ? Thanks.

  33. Schrodinger's Cat

    The IPCC’s claim of increasing confidence levels does not impress me.

    The unpredicted hiatus is a major blow to the IPCC and exposes the serious problems with their models. It has thrown the movement into complete uncertainty, not just in terms of scientific understanding, but also in how to stay on message about CAGW.

    If they accept that some natural process has negated the warming then it follows that the same natural process may have caused some or all of the warming in the first place.

    What to do? They decided to adopt a bullish lie, a bluff. It is a desperate attempt to head off an attack on their credibility. Their claim of greater confidence is so outrageous that it wrong footed their critics. It also impressed the gullible believers.

    The claim is a political ploy. Amazingly, it was a gamble that seemed to work. However, when viewed as a scientific claim, it is completely irrational, it is unbelievable and it is clearly not true.

    This leaves an ambiguity for the observer. Is the IPCC essentially a political organisation? If it is a scientific organisation, how does a result that invalidates a model improve confidence in the model output?

  34. The more we learn
    The more we realize
    The less we know

  35. Tony,

    Tsk! Money, money, money, that’s all you think about. )

    Beth- the – serf – who – is – used – ter – doing – without
    – it.

  36. “90% => 95% confidence level”

    It is becoming increasingly apparent that IPCC is engaged in a “confidence game”.

  37. Here’s an interesting uncertainty. Taking the Gulf Stream transport reconstruction and modern measurements would make it appear that heat transport continued to increase past 1950 to about the 32-33 Sv range. It has now slipped down closer to 31 Sv this last decade which would put it about where it was in 1950. We could be cooling folks. For how long even Kim doesn’t know.



  38. Two basic requirements for each successive IPCC report, in order to maintain the fear-driven momentum:

    – “It’s worse than we thought” (SL and RCP8.5 projections)

    – “We are more certain of this than before” (95% vs. 90% on 20thC warming)


  39. I probably should know better, but – why not reintroduce the term “natural philosopher”?

    The term “scientist” gives totally undeserved credence to all sorts of deluded followers of fashion. Their main function seems to be to gradually bleed the taxpayer dry, by inducing fear and terror into the unsuspecting populace.

    And the benefits of the so-called “science” of climatology are – ?

    No answer, was the stern reply!

    And now I must bid you, for the moment, adieu!

    Live well and prosper,

    Mike Flynn.

  40. IPCC losing credibility in Switzerland

    Nigel Lawson Swiss interview

    This interview was published here by the “Tagesanzeiger”, usually a “pro-CAGW” paper.

    An earlier article by P. Gosselin in the (normally more “skeptical”) “Weltwoche”, raises some of the same points and states that public fear of CAGW and trust in IPCC have dropped considerably both in Switzerland and in Germany.

    It seems to be the “chickens coming home to roost”, arguably resulting from IPCC’s “sweeping under the rug” (our hostess’ expression) the pause and its impact on 2xCO2 climate sensitivity estimates, as estimated by several recent observation-based studies.


  41. Rumsfeld said it better, and was more honest than the Anthropowarmistas:

    There are known knowns; there are things we know that we know.
    There are known unknowns; that is to say, there are things that we now know we don’t know.
    But there are also unknown unknowns – there are things we do not know we don’t know.

    The Anthropowarmistas can’t even admit the known unknowns.

  42. Increased certainty (IPCC style):

    – in our last report we were 90% certain that the late 20thC warming was caused mostly by human GHGs

    – our models told us we should see an average warming of 0.2°C over the next two decades

    – since then we have revised our 2xCO2 climate sensitivity

    – over the past 12 years human GHG emissions have risen unabated and atmospheric CO2 has increased from 373 to 395 ppmv

    – on this basis our models tell us we should have seen warming of 0.12°C to 0.37°C – or a mean estimate of 0.25°C

    – however, we have seen a slight cooling of around 0.025°C over the past 12 years instead

    – we think that some heat may have disappeared into the ocean, or maybe there was some unusual natural variability causing cooling or maybe there was some cooling due to Chinese aerosols, or…

    – on this basis, we our now able to say that our confidence level on late 20thC warming has risen from 90% to 95%

    (That’s “science”, folks.)


    • Correction

      …we have seen a slight cooling of around 0.025°C 0.045°C over the past 12 years…

  43. “The pause in global surface temperature anomalies for the past 15+ years is arguably an example of negative disconcerting learning.”

    Yes, indeed. Scientific research can take on a kind of ‘random walk’ behavior. While all serious research can and does provide useful knowledge, sometimes unexpectedly, efficiency in applied research in the real world is important. Unfortunately it is all to easy for the tr searcher to get trapped in an unproductive direction.This appears to be the IPCC’s dilemma Its work is becoming self-contradictory and it appears to be unable to break out of this trap. It is hard to think of a solution that does not include the break-up of the IPCC., .

  44. Each side of the debate has erected a solid wall around a core group of truths that support the policies they wish to advance. Those truths really are real and form a reasonable core for each side.

    It’s hard for a confirmed old Leftist like myself to echo the Gipper, but until each side tears down their wall, the siege of both camps will continue.

    It is warming when measured on the appropriate time scale. It is entirely possible that humans have contributed to this warming, in part by emissions of CO2. It is logical that we should investigate this and the sums of money spent doing so to date are appropriate for the task assigned.

    Early proponents of the political position arguing that warming was causing negative effects already and required prompt and massive responses overstated their case, often consciously. They engaged in unethical and occasionally illegal acts to protect the alarmist point of view. And they consistently overstated the extent of what science can truly say about the state of the climate and humanity’s effects on it.

    When the standard industrial response to this was supplemented by non-funded and ‘clean hands’ opponents to AGW, the alarmists attempted to tar them with the same brush as used to taint the Big Tobacco lobbyists from an earlier era. That started the climate wars which show no side of ending.

    That’s where matters stood when I started following the debate in 2007. That’s where we stand now. We just slot new stories into the same place on the debate rostrum without it changing anyone’s thinking, debate points or political goals.

    While we engage in this, the world is busy developing. We will use six times as much energy in 2075 as we did in 2010. Over half of this energy will come from coal. We are sleepwalking into a future that has climate issues, pollution problems and fossil fuel portfolio disaster written all over it.

    But the debate is fun, I’ll grant you.

    • Ton

      You said;

      ‘It is warming when measured on the appropriate time scale.’

      What is the length of the ‘appropriate time scale?’ You are much too sophisticated to claim it is only since 1880, so what is your measure?

    • Tom Fuller,

      “It’s hard for a confirmed old Leftist like myself to echo the Gipper, but until each side tears down their wall, the siege of both camps will continue.”

      Don’t worry, you didn’t. Now, if Reagan had said, Mr. Gorbachev, Mr. Kohl, tear down these walls,” you could use his speech to make your point. The left complaining about the hard headedness of the right on CAGW is like the husband who comes into court on a domestic violence beef, and brings pictures of the scratch marks on his hands and arms.

      “Yer honor, look what she did for me.”

      Poor guy, until somebody shows the judge the video tape of him hitting, kicking and choking the wife; and her scratching his hands and arms trying to get his hands off her throat. The left has been using CAGW to try to centralize control of, and decarbonize, the western economy since 1988.

      The wall the left has built is indeed like the Berlin Wall. The wall the right is trying to construct is more like Hadrian’s Wall – to keep the barbarians at bay.

  45. Hi Tony, how are you?

    I just look back to the last peak at the MWP. That seems to be an adequate time frame.

  46. The Pause has succeeded in getting at least some consensus climatologists to start thinking with their brains instead of their politics.

    So regardless of whether temperatures go up, down, or nowhere, in the coming decades, the science is the better for it.

  47. It is obvious they don’t have a clue about what causes the temperature to go up or down but they are 100% certain that to influence policy they have to pretend they do, The uncertainty for us is knowing a) what will stop them lying? and b) How much havok will they cause before they stop lying?