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Mythic Reasoning about Climate Uncertainty

Posted on 29 August 2011 by muoncounter

In her June 2011 paper, Reasoning about climate uncertainty, Dr. Judith Curry earns a place of honor in the pantheon of climate myth-makers.  The paper takes us on a perilous journey from climate science to the realms of semantics and psychology; along the way, we find we must do battle with a monster.  All the elements of an epic myth!

This paper argues that the IPCC has oversimplified the issue of uncertainty in its Assessment Reports, which can lead to misleading overconfidence.

An auspicious start, promising scientific insight above and beyond the now-famous "Wow."   But by "oversimplified the issue of uncertainty," isn't she really saying 'understated the uncertainty'?  What does the ambiguous "can lead to" mean?  That phrase could apply to just about anything (including the tendency of horses to refuse a drink).

The remainder of the paper neither presents new evidence nor makes any attempt to argue against existing evidence .  We find instead, this lesson in stylistic criticism:

In practice, primary conclusions in the AR4 included a mixture of likelihood and confidence statements that are ambiguous. Curry and Webster (2011) have raised specific issues with regards to the statement “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations,” that are related to apparent circular reasoning in the attribution argument and ambiguity in the attribution statement itself.  --emphasis added

According to Dr. Curry's online publication list (as of 20 Aug 2011), Curry and Webster 2011, entitled "Climate science and the uncertainty monster," is in review for publication in the Bull. of the American Meteorological Society.  An online preprint is available here.

The 'uncertainty monster' is given teeth here:

The “monster” is therefore the confusion and ambiguity associated with knowledge versus ignorance, objectivity versus subjectivity, facts versus values, prediction versus speculation, and science versus policy.  The uncertainty monster gives rise to discomfort and fear, ....

The vital question of scientific uncertainty has nothing to do with knowledge vs. ignorance or science vs. policy; it has everything to do with accurate determination of physical quantities, and the confidence one may place in the validity of those measurements.  This is given serious treatment by serious workers:   See this post by tamino, who draws a useful line between a trend and various types of noise that may obscure the trend, and this SkS post by hfranzen, who discusses uncertainty as inherent in the type of science being done.   Dr. Curry's paper has turned a serious question on its head; by anthropomorphizing the concept of uncertainty, it is something to be feared rather than understood.

We have thus entered a myth worthy of Lewis Carroll:

"Beware the Jabberwock, my son!
The jaws that bite, the claws that catch!
Beware the Jub-Jub bird, and shun
The frumious Bandersnatch!"


Look again at the IPCC statement labeled as ambiguous: 

“Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations”


The IPCC AR4 chapter 1 section 1.6 unambiguously specifies 'very likely' as more than a 90% probability of occurrence.  The only possible ambiguity is the word 'most' (and certainly we can agree that 'most' means 'more than 50%').   If the IPCC had stated a specific percentage, skeptics could just as easily pick at the number (or the number of significant digits).  Arguing the choice of words, rather than the evidence, is a sure sign that thre is little evidence on her side.  But myths don't need evidence.

What we read next comes sounds like psychological analysis:

“All else being equal, individuals tend to be significantly better at detecting fallacies when the fallacy occurs in an argument for a conclusion which they disbelieve, than when the same fallacy occurs in an argument for a conclusion which they believe.”

That statement, an outgrowth of confirmation bias, is surely a sword that cuts both ways!

"As more and more peers weigh in on a given issue, the proportion of the total evidence which consists of higher order psychological evidence [of what other people believe] increases, and the proportion of the total evidence which consists of first order evidence decreases . . .  “Over time, this invisible hand process tends to bestow a certain competitive advantage to our prior beliefs with respect to confirmation and disconfirmation. . . In deciding what level of confidence is appropriate, we should take into account the tendency of beliefs to serve as agents in their own confirmation.”

Unfortunately for this argument, it is the weight of the evidence of climate change in general and anthropogenic influence in particular that continues to grow; the 'invisible hand' has no documented effect on the scientific community.  Given all the public scrutiny, what climate scientist merely accepts the conclusions of his or her peers solely because 'that's what the experts say'?  Given the relative ease of access to data, why would anyone with a truly skeptical mind do that?

We find instead that this 'invisible hand' pushes those who self-identify as 'skeptics' to denying the data and the physics.  Denial pushes people towards increasingly radical positions, such as the rejection of science simply because of a lack of trust in 'experts.'  From there, it is a short trip to leveling accusations of manipulating data for financial gain and declaring that those are the opposite side are out to destroy their way of life.  Those in denial don't need to ask for evidence of any of these things; they know these things to be true because that's what their myths tell them to believe.  True skeptics and serious scientists don't think that way.

Finally, we read this:

The consilience of evidence argument is not convincing unless it includes parallel evidence-based analyses for competing hypotheses. Any system that is more inclined to admit one type of evidence or argument rather than another tends to accumulate variations in the direction towards which the system is biased. ... To be convincing, the arguments for climate change need to change from the one-sided consilience of evidence model to parallel evidence-based analyses of competing hypotheses.

This would be possible had the mythic uncertainty monster not left such a strong impression: We don't know enough or won't ever know enough to have a rational debate between competing hypotheses.  Pity there, because most of the 'competing hypotheses' are themselves myths already rebutted here at SkS.

Myths grow via retelling.  In this paper,  Dr. Curry acknowledges the "contributions of the Denizens of my blog Climate Etc. for their insightful comments."   In so doing, the myth-peddler sets a dangerous precedent.  Can scientists who also write blogs now repackage a selection of their followers' comments in the form of scientific publication?   If true, this is a quantum leap in the power and reach of the pseudo-science blog and a handicap for those that merely practice actual research.  We are truly at the door to the Land of Make Believe.  Or as Dr. Curry likes to put it, 'we've been busy slaying the skydragons'.

Carroll (a mathematician, whose real name was Charles Dodgson) would enjoy the metaphorical slaying of the 'uncertainty monster ':

"And, has thou slain the Jabberwock?
  Come to my arms, my beamish boy!
O frabjous day! Callooh! Callay!'
  He chortled in his joy.

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Comments 51 to 74 out of 74:

  1. trunkmonkey wrote: "We have seen the models founder at the decadal time scale... " Well duh! Of course they founder on a decadal scale because on a decadal scale what you see is dominated by chaotic features of internal climate variability, not the effects of the forcing. Only someone completely ignorant of the workings of climate models would expect models to perform well on a decadal timescale or very small spatial scales (e.g. station data). Models are just getting to the point where decadal predictions may be worthwhile, hence the next IPCC report is likely to mention them as an active area of research. See this thread at RealClimate So, exactly what was the point you were trying to make when you wrote "the models founder at the decadal timescale"?
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  2. rcglinski#50 I don't understand what you're objecting to. Translate the IPCC statement into numbers if you like: There is a 90% or better chance that 51% or more of the observed increase in global average temperatures since the mid-20th century is due to the observed increase in anthropogenic greenhouse gas concentrations. The meaning is clear. Of course, 'most' is probably higher than 51%. But that is worst case; where's the problem?
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  3. Nope, but I'll take some dried figs if you have any left. They help loosen the, uh, "isms." Baked peaches do that too, and I just had some. Here, I'll demonstrate: trunkmonkey: "Postmodernism reacted that emergent phenomena in complicated systems made them irreducable, at least in their behavior." That's just another way of saying "structures are not absolute." It's Marx correcting Hegel. Where do you go from there? You imply that models are pointless because they are structures trying to represent complex systems featuring emergent phenomena. So what? Is that an attack on models? If so, from what position do you attack? Do you have anything better to offer? Or do you wander around without a plan all day? Or you have a plan but it causes you great angst because you know it's ultimately pointless? So, yes, it was a joke, but probably not the kind that gets a laugh from the audience. Post-structural thought has been around for a long time (Chaucer exhibits it on occasion). It is only the condition of postmodernity that allows it to gain a special importance. That importance is in the service of rejecting any sort of metanarrative (God, Nation, ethical systems) that might place obligations on the individual as the individual operates (tries to survive) under the current mode of production. It works to break down socially-constructed morality, which can then be replaced with the morality of the 'free market' (Objectivism, in one form). The individual ends up being the ultimate source of truth, choosing whatever truths serve individual interests. And, I must say, what's up with that?
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  4. 'We have seen the models founder at the decadal time scale... " Climate models suck at predicting the stock market and predicting tomorrow's weather too, because , well because they are climate models - eg models to predict 30 year averages. Your point?
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  5. muoncounter #49 "There may be differences in the numbers, but there is minimal uncertainty as to the mechanism and the cause. As Denning says, physics doesn't care what you believe. Arguing over the last decimal place is silly; it's real, it's happening. Stop denying that and do something about it." As a bit of a lukewarmer myself, I think that the differences between Drs Trenberth and Hansen are more than the odd decimal place. The stasis in surface temperatures is more difficult to explain in terms of standard AGW theory which posits an increasing warming imbalance. Dr Curry is certainly opaque in expression, but I see her position as an attempt to show that the uncertainties are more important than previously thought and 'motivated reasoning' is a nice term for exaggeration.
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  6. critical mass - "The stasis in surface temperatures is more difficult to explain in terms of standard AGW theory which posits an increasing warming imbalance" Not at all. The mid 20th century saw cooling caused by man-made aerosols - following the rapid industrialization and growth after the 2nd World War. And it looks like the rapid growth in East Asia (especially China) may have caused the same during the 'noughties'. See these Sks Posts: Why Wasn't The Hottest Decade Hotter? & Michaels Mischief #1: Continued Warming and Aerosols We'll have further posts on the subject, but the relevant papers are still awaiting publication in the scientific literature.
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  7. DSL You are correct that emergence was originally post structural. My comments were neither an attack nor advocating post modernism, which i agree quickly degenerates into a nihilistic ennui. I am interested in the possibility that some complex phenomena may be irreducable and that others might require models built at a size approaching the scale of the phenomena, ie clouds. This is not to argue that we throw up our hands and go home. We have non mathematical tools of inquiry far more valuable than collecting postage stamps. The issue is uncertainty. Nobody writing here is unconcerned. Judith Curry is concerned. Skeptics are less positive that we can predict the outcome.
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  8. Now I'm eating red beans and rice, so we'll see what that produces. The last bite is the one remembered: "We have seen the models founder at the decadal time scale . . ." Without anything else to go on, the comment appears to be a "hey, models fail" type of attack. More context necessary. I don't think Curry's response to the uncertainty is reasonable. Why? The little bits of evidence here and there suggest that she's not interested in forming a professional opinion. She's more interested in selling a position. The "Wow" comment is just the latest little bit. When was the last time Gavin Schmidt blogged that type of unstudied reaction to an ill-considered claim with no available methodology? The problem has always been uncertainty. Indeed, that is the only problem. Yet there is an attitude on Curry's blog--in the comment stream (a comment stream she is responsible for correcting from time to time)--that suggests that the ultimate goal is to prevent movement toward certainty. How many people in the comment streams on the denial blogs would like to see the climate scientists who support the theory of AGW fired? And what would then happen to climate science? That second question is never considered, and it leads me to believe that the main goal of those people is not progress toward certainty but the silencing of scientific progress. As far as I am concerned, the entire universe in all its dimensions is the irreducable phenomenon. Any part must be read within the context of the whole. Sounds daunting, but there are patterns and regulations that work with regularity in most conditions.
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  9. trunkmoney The IPCC acknowledges uncertainty, too. Every scientist I know acknowledges uncertainty. That does not influence their opinion about whether humans are affecting climate. In fact, it generates even more concern, because we can constrain the upper bounds of possible change less than the lower bounds. As far as I can tell, skeptics are not arguing that there is uncertainty, they are arguing that there is bias. That is quite a distinct thing. As for Curry, taken to its logical conclusion her writing seems to suggest that 1) it is impossible to address complex multivariate phenomena without engaging in pattern-seeking "motivated reasoning" and 2) that scientists are somehow not aware of the pitfalls of confirmation bias in such cases. Those statements reflect both nihilism and naivete in turn. While her audience in accepting these arguments engages in their own form of confirmation bias or motivated reasoning, Curry conveniently fails to mention that there are well established ways to avoid the same problem - namely by making novel predictions that are open to test and by incoporating all relevent dependable information without prejudice. Climate scientists have, from I have seen, employed these methods repeatedly in their endeavors. I do not think the same can be said of Salby, Carter, Plimer etc...
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  10. trunkmonkey wrote: "Skeptics are less positive that we can predict the outcome.". If that is what skeptics do, what do you call those who try and make a fuss about the models not being able to do something that nobody would claim they are able to do (such as not foundering when making decadal predictions)? There are those who are genuinely interested in communicating the uncertainty resulting from our current limited state of knowledge about climate physics, and there are others who merely want to disrupt the discussion with red-herrings (or indeed red, white and green flag shaped herrings).
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  11. trunk#57: "Nobody writing here is unconcerned" There are some who feel it's not happening or it's not bad or it's not our doing. Those each lead to lack of concern, apathy and eventually denial. An overstatement of uncertainty gets to the same point via a longer, more torturous path. If Curry's conclusion is 'we can't be sure' because IPCC language is too fuzzy or climate systems are too chaotic or whatever the reason du jour, then others will come down on the side of doing nothing based on her words. End result is the same.
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  12. Muon: "An overstatement of uncertainty gets to the same point via a longer, more torturous path. If Curry's conclusion is 'we can't be sure' because IPCC language is too fuzzy or climate systems are too chaotic or whatever the reason du jour, then others will come down on the side of doing nothing based on her words. End result is the same." And she knows that.
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  13. "Skeptics are less positive that we can predict the outcome." Do you think that is a reason for inaction? Uncertainty cuts both ways. It could be worse than the conservative predictions of IPCC.
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  14. scaddenp#63: "Uncertainty cuts both ways." Would that it did, but 'skeptics' have absolute belief in their myths. They know that natural cycles, for example, are more important than greenhouse gases could ever be. How they know this is of course unclear, but it doesn't seem to matter. The skeptical 'its a natural cycle' must therefore be met with a resounding 'how do you know that?' and 'what is your uncertainty?' If there could be a rational answer to those questions, then we could have a slightly more level playing field.
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  15. I am curious as to what everyone would say is the contribution to the industrial-era warming and uncertainties from the following forcings: CO2, urbanization, solar, ENSO, volcanic activity, and albedo (feel free to add others as deemed appropriate).
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  16. Jonathon I see little reason* to depart from the forcings and uncertainties given by the IPCC: BTW, ENSO is not a forcing, it is an element of internal variability and if by "urbanisation" you mean the urban heat island effect, then urban areas are such a small proportion of the Earths surface that their effect on actual (rather than as estimated by raw area-weighted averages of surface station data) global surface temperatures is essentially insignificant. * There are other forcings not mentioned in the table, e.g. the GCR theory, however the current level of scientific undersdtanding (LOSU) and observational evidence do not suggest that they will substantially alter the overall picture.
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  17. Thank you Dikran, While urban heat islands are a small portion of the Earth's surface, they have an area-weighted averages (as you pointed out) much higher. GISS attempts to remove these effects from their temperature data, but I have not seen others to likewise. ENSO is not a true forcing in that it will even out in the long run. However, it can have large short-term effects in the temperature record. I probably shoudl have re-worded my question to the observed warming during the industrialization era (1880 - present). The solar influence seems awfully small compared to other sources.
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  18. Jonathon - "The solar influence seems awfully small compared to other sources." That's because the forcings listed in that table are the changes in forcings that are then changing the climate. Solar energy is the driving force of the climate, but because it has not appreciably changed since the start of the industrial era, it isn't appreciably responsible for the changes in global temperatures over that period. GHG levels, on the other hand, have changed a lot, and those are the dominant influences on changing global temperatures.
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  19. Jonathon GISS is not the only surface temperature dataset that compensates for urban heat island effect, all of the major surface temperature datsets do this. Assessing and compensating for these sort of non-climatic issues are probably 95% of the work involved in generating the datasets. Just computing the area-weighted averages from the data from the global historic network is about a mornings work for a competent programmer. Whether something is a forcing does not depend on whether it will even out in the long run - it is a matter of the physical nature of the process. ENSO has a short enough period that it has fairly little effect beyond 30 years or so; that is why climatologists use 30 years as the default period for computing trends etc. it is long enough not to be too strongly affected by internal variability, but short enough to detect the effects of changes in the forcings. See KRs excelent explanation about the solar forcing.
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  20. DM #66 and KR#68 The forcings shown in the table from IPCC AR4 are all at 2005 referenced to year 1750. This makes all the forcings except Solar both relative (changes) and absolute numbers because there were assumed to be zero anthropogenic effects in 1750. Not so with Solar. We cannot assume that the Solar forcing was zero in 1750, because that would imply that the planet was at equilibrium - neither warming nor cooling. Hence the 0.12W/M2 'change' from 1750 is not effectively referenced to zero as are the other forcings. For example if the sun was warming the Earth at a rate of say 0.5W/M2 in 1750, then the absolute value in 2005 would be 0.5 + 0.12 = 0.62W/M2. It could be a negative number if the Earth were cooling in 1750 but the liklihood is that it was warming out of the little ice age. In my example the 0.62W/M2 should be added to the total forcings and not the 0.12W/M2. Dr Hansen is saying in his latest paper that the Aerosol cooling is about -1.5W/M2 which reduces the above IPCC totals to about 1.3W/M2 and the climate responses are about -0.7W/M2 which makes the net imbalance about 0.6W/M2. The solar forcing effect is therefore minimized in the IPCC table and could be more significant, particularly given the low LOSU of the aerosol and other forcings.
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    Moderator Response: [muoncounter] We're now solidly off-topic. Please take solar forcing discussion to a more appropriate thread, such as the intermediate version of 'It's the sun'.
  21. Gag. The uncertainty monster is in press. Our fearless mythologist addresses the following important issues: Monster hiding. Uncertainty hiding or the “never admit error” strategy can be motivated by a political agenda or because of fear that uncertain science will be judged as poor science by the outside world. Apart from the ethical issues of monster hiding, the monster may be too big to hide and uncertainty hiding enrages the monster. And I thought that was the hallmark of the deniersphere. Monster exorcism. The uncertainty monster exorcist focuses on reducing the uncertainty through advocating for more research. This is as opposed to those scientists advocating less research. Monster simplification. Monster simplifiers attempt to transform the monster by subjectively quantifying and simplifying the assessment of uncertainty. Monster simplification is formalized in the IPCC AR3 and AR4 by guidelines for characterizing uncertainty in a consensus approach consisting of expert judgment. We get it, consensus = bad. When we hear that 9 out of 10 doctors agree, it must be that one brave holdout, Dr. Nick, who is correct. After all, he's got a degree. Did no one write a real paper for this month's Bulletin?
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    [DB] As you point out, this guy would have been a worthy candidate, had he been real.

  22. #71: Curry's resorting to hand-waving and wild speculation I see. Has she never read a real science paper? Quantifying uncertainty is a crucial step in presenting results, while failing to quantify uncertainty is the hallmark of a variety of recent failed skeptic papers, such as Spencer and Braswell. Epic fail from the Curry.
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  23. Muoncounter @71, Re the Cury and Webster paper-- WTH? This is now what "skeptics" are peddling as science? I agree with SkyWatcher, another epic fail for Curry-- I thought her "Italian flag" analogy was so bad that it would be impossible to beat, now we have a "monster" analogy, I was wrong. I tried to read the paper, but I couldn't, just too bad. Very sad that such a poor paper is appearing in a respected journal like BAMS.
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  24. This myth lives on without end. Here is JCurry giving the Uncertainty Monster talk in Santa Fe, complete with graphics poking fun at various scientists and the very idea of consensus: Don't listen to what one scientist says. Listen to the consensus reached by over a thousand scientists. As if it is inherently bad when more than one researcher finds the same thing. Isn't that the way it's supposed to work? These folks continue to drag science down the drain. Then she makes her pitch for 'scientific integrity.' This was a dinner talk - hope nobody had to make a run for the exit!
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