Climatic Change special issue on uncertainty guidance for the IPCC: Part II

by Judith Curry

Uncertainty abounds in issues related to climate science and climate changes, the impacts of those changes, and the efficacy of strategies that might be used to mitigate or adapt to change. There are, however, a few things about which we can be quite certain. There are also a number of things about which many people are certain, but should not be.

The above words comprise the abstract of a paper by Morgan and Mellon in the Climatic Change special issue on uncertainty guidance for the IPCC.  This special issue was discussed previously on this post.   Most of the papers were behind paywall.  The publisher, Springer, is making all of its journal publications public access for the month of December, so I have downloaded the remaining papers from [here].  Here are links to the papers that were not discussed or linked to on the previous thread:

Reducing doubt about uncertainty: Guidance for IPCC’s third assessment.  Richard H. Moss [link moss]

Treatment of uncertainties in IPCC Assessment Reports: past approaches and considerations for the Fifth Assessment Report.  Michael D. Mastrandrea and Katharine J. Mach   [link mastandrea]

Differentiating theory from evidence in determining confidence in an assessment finding.  Kristie L. Ebi  [link ebi]

Applying the science of communication to the communication of science.  Baruch Fischhoff   [link fischoff]

Certainty, uncertainty, and climate change.  M. Granger Morgan and Carnegie Mellon    [link morgan]                                                                               .

Defense community perspectives on uncertainty and confidence judgments.  Marcus King and Sherri Goodman  [link king]

Communicating climate change risks in a skeptical world.  John D. Sterman  [link sterman]

Certainty, uncertainty and climate change

I’ve selected one of these papers to highlight:  the paper by Morgan .

This paper argues for the use of formal expert elicitations, as an alternative to the consensus seeking approach of the IPCC.  Some excerpts:

While the IPCC has yet to make use of them, there are methods that allow an even more precise characterization of uncertainties. “Expert elicitation” involves a set of techniques first developed in the decision analytic community. Subsequently, the methods used to perform elicitation have been informed by the work of a number of experimental psychologists who have demonstrated that, without being aware of it, people use a variety of cognitive heuristics when making judgments about uncertainty. While these heuristics work well in many settings, they can also give rise to a variety of biases when making judgments under uncertainty.

There is clear experimental evidence that both experts and laypeople are systematically over confident when making judgments about, or in the presence of, uncertainty. Expert elicitation cannot eliminate the problem of biases caused by the operation of cognitive heuristics, nor can it eliminate overconfidence. But unlike more informal methods  such as group discussion (in which the same cognitive heuristics and tendency to overconfidence operate) what it can do is work systematically to try to identify and minimize such problems.

Since the early 1990s my colleagues and I have conducted four detailed expert elicitations in which we have obtained judgments from leading climate and ecosystem scientists about uncertainty in the value of a variety of key climate variables and impacts.

One hopes that research will lead to a reduction of uncertainty and at least some decision analysts appear to assume that this will always be the case. However, our respondents were all experienced scientists who understand that often research identifies unforeseen complexities, and thus, at least for a while, can increase rather than decrease uncertainty. Thus, for example, in Morgan and Keith (1995) we asked respondents to assess the probability that their uncertainty about the value of climate sensitivity would grow by 25% or more after a 15-year program of research at 1-billion $/year. The responses we obtained ranged from 0.08 to 0.30 (average value of 0.19). We have found similar results in our more recent elicitations. While such results are not surprising to experienced scientists, they do come as a surprise to some analysts and decision makers who view research as always reducing uncertainty.

Quantitative expert elicitation can be a very useful tool to identify and display the divergence of opinion within a field. It can do so with much greater clarity than qualitative statements of the sort produced by IPCC writing teams. 

6 Selecting the right tools and the need to develop new ones

While doing a good job of characterizing and analyzing uncertainty, and of communicating uncertainty, is very important, perhaps even more important is selecting the right tools to do climate-related assessment. Most of the conventional tools of policy analysis implicitly assume that:

1. There is a single (public-sector) decision maker who faces a single problem (in the context of a single polity);

2. Values are known (or knowable), static, and exogenously determined;

3. The decision maker should select a policy by maximizing expected utility;

4. The impacts involved are of manageable size and can be valued at the margin;

5. Time preference is accurately described by conventional exponential discounting of future costs and benefits;

6. The system under study can reasonably be treated as linear;

7. Uncertainty is modest and manageable.

Despite years of modeling that seeks an optimal global climate policy, it should be obvious to all that what is optimal for the Inuit of Northern Canada, the Quechua and Aymara-speaking peoples of the Andes, or the Anglo population of Australia will not be the same. How those, or dozens of other communities, will value goods, services and ecosystems 50 to 100 years from now is also deeply uncertain, and likely to depend in critical ways on cultural and path-dependent processes.

53 responses to “Climatic Change special issue on uncertainty guidance for the IPCC: Part II

  1. I don’t usually agree with Granger Morgan but there are some things to like here. Most important is “often research identifies unforeseen complexities, and thus, at least for a while, can increase rather than decrease uncertainty”. This is precisely what has happened with climate research over the last 30 years and it needs to be recognized.

    As for methods, if his method can do this I am all for it: “Quantitative expert elicitation can be a very useful tool to identify and display the divergence of opinion within a field.”

    I also like this: “There are also a number of things about which many people are certain, but should not be.”

    Historical note: Morgan runs the Engineering and Public Policy Department at Carnegie Mellon, a department which I helped develop in the early 1970s. CMU was heavily into applied decision theory at the time, and probably still is. If one is going to do decision making under uncertainty (as it is called) it is very important to accurately grasp that uncertainty. (That is why I developed the issue tree at CMU in 1973.) The IPCC has utterly failed to do this.

    • David – I often attend EPP seminars. Cheers.

      • The Department of EPP started as a program, in which I taught “Technology and Public Policy” and “Philosophy of Technology.” Our concern was that the US EPA, then newly formed, was ignoring engineering realities in overly zealous regulatory attacks on industry (something they still do). When Morgan took over the department he took it in a Green direction instead, but I was gone by then. I am sure they do good work, by and large. CMU is a great school.

      • Re “EPA . . was ignoring engineering realities in overly zealous regulatory attacks on industry (something they still do).”
        As evidenced this week by: EPA Tries To Pull a Fast One

        Industry groups have estimated the costs at $40 billion to $120 billion for full compliance, with many older coal and oil-fired plants forced to close. Illinois, Ohio, Indiana, Missouri, and Michigan are the hardest-hit, because they are home to the oldest plants with the fewest emissions controls. . . .
        These vast projected savings from asthma make no sense. America’s air has been gradually getting cleaner since 1980, as EPA’s own data show, but the number of children with asthma has risen. According to the Centers for Disease Control, 3.6 percent of children had asthma in 1980, and almost twice the percentage, 7.5 percent, in 1995. . . .
        CDC acknowledges that “the causes of asthma remain unclear and the current research paints a complex picture.”

    • I like the idea of a “red team” approach. I think this opens the door to it. I hope I am using the term correctly. I disagree with Richard Tol that “the experts, by definition, contributed to the literature”. There are lots of talented people out there, who aren’t climate scientists, or economists, who are capable of understanding the fields in enough detail to provide independent assessment. Though they may not be “qualified” when they start, they become qualified through the process. We really need to move past people reviewing their own work. Just thoughts.

    • Compare:

      The Public Policy Forecasting special interest group (publicpolicyforecasting.com) has been established to provide a platform for the rational analysis of governments’ policies.

      They seek to apply objective principles of scientific forecasting to avoid common biases, similar to the double blind methodology required by clinical research.

      • David, Scott Armstrong is a professor of marketing, a crackpot who styles himself the inventor of “scientific forecasting” a made-up field that makes astrology look like particle physics.

      • Robert
        Please study the reasons for double blind experiments.

        Double-blind describes an especially stringent way of conducting an experiment, usually on human subjects, in an attempt to eliminate subjective bias on the part of both experimental subjects and the experimenters. In most cases, double-blind experiments are held to achieve a higher standard of scientific rigor.

        Then give the pros and cons as to why we should not require double blind methodology in climate modeling – when the financial stakes of the policy decisions are 100 to 1000 times larger – and where the financial flows can be directed by political activism and by biasing the scientific process towards desired outcomes.

        Give reasons for/against why we should/not apply Andersen’s Scientific Forecasting methodology.

        Until you can cogently address these issues – you but paint yourself as the “crackpot” who is naive and ignorant of the issues.

  2. The best thing about this is it provides a way to establish traceability. Expert elicitation may sound like fluff to some, but as Morgan et al note it is reams more objective than undocumented meeting-room negotiations. There’s a time and place for both approaches, and it’s about time for the former in climate change assessment. It also may prove fertile ground for a red team approach. (?)

    #4 and #5 are very interesting, and under-discussed at present.

  3. Uncertainty is the security of…I didn’t know… so the theories are still being protected no matter how bad the outcome of the models declare anything.

  4. Despite years of modeling that seeks an optimal global climate policy, it should be obvious to all that what is optimal for the Inuit of Northern Canada, the Quechua and Aymara-speaking peoples of the Andes, or the Anglo population of Australia will not be the same.

    That’s not particularly obvious. Indeed, it’s a big assumption. Much like depleting the ozone layer, making bird flu easily transmitted, or a general exchange of thermonuclear bombs, BAU global warming is the sort of ill wind that blows nobody any good.

    In the details of how to mitigate and (and, not “or”) adapt to climate change, there will be different courses of action that share the costs and benefits differently. But it is in no one’s interest (excepting a few people invested heavily in fossil fuel extractors) to continue on the current path.

    • “BAU global warming is the sort of ill wind that blows nobody any good.”

      What?

      You mean, due to destabilization of the global economy via climate refugees etc.?

      Clearly, someone is going to directly benefit somewhere, and I don’t just mean oil company executives. So I guess you are saying that in nearly all cases, the indirect negative effects are going to outweigh the direct benefits, where they exist?

      Strong claims need to be backed by strong evidence :)

      • & it’s not even remotely net negative like in your 3 examples.

        You have a point, but you’r WAY overselling it.

        Cheers.

      • “Clearly, someone is going to directly benefit somewhere, and I don’t just mean oil company executives.”

        Like who? A wise man said: “Strong claims need to be backed by strong evidence.”

        What is your evidence that radically changing the earth’s climate will directly benefit anybody?

      • Well, Robert, I am speculating, but here’s the gist:

        Somewhere in the world, it will get some combination of warmer/wetter and crops will grow better. Maybe Canada, I don’t know exactly where. Nobody does but one can make educated guesses.

        Hell, use the same logic as is used to argue for sacrifices for mitigation’s sake. We benefit today, future generations suffer. See the “we benefit today” part?

        Let’s put it to a vote, or make a bet.

      • Somewhere in the world, it will get some combination of warmer/wetter and crops will grow better. Maybe Canada, I don’t know exactly where.

        Could you be any more vague?

        I wouldn’t call that strong evidence — or any evidence, really — for the claim that some will benefit from global warming.

      • Heh – it’s stronger evidence than any for your statement I originally quoted, for which there is NO evidence. No need to get out the big guns here.

        You need to argue net utility, and you know it. TTMO….

      • @Robert | December 28, 2011 at 11:38 am;

        For one, global agriculture will benefit as a whole, and particularly in temperate climates, including the vast expanses of North America, Northern Europe and parts of Northern and Central Asia, as well as the Southern Cone of South America plus New Zealand and parts of Australia). Direct benefits (in the form of farming and related revenue) would accrue to the farming areas enabled or improved by warming (expanding cultivable areas, extending the no-frost window, increasing CO2 fertilization, etc). Indirect benefits to all humanity because of increased food supplies.
        Of course agriculture is in itself a form of adaptation of human activity to prevailing climate, thus any assessment of climate change on agriculture should take into account the expected response of farmers as well as the expected response of plants and animals in the face of changed temperatures and precipitation. Crops would shift pole-ward, crop mix would change in every location as the climate changes, etc. Of course some dry tropical areas may suffer from reduced agricultural production if no new varieties or new crops can be grown or animals raised (or new farming practices and water management systems can be introduced) over the century or so required for the climate to become problematically warmer/drier in that specific location, but this is more the exception than the rule.
        Existing integrated assessments of this matter indicate that food supply worldwide (total and per capita) would greatly increase as a result of IPCC projected climate change, and the prevalence of undernourishment (or “people at risk of hunger”) meaning people lacking access to sufficient and adequate food) will greatly diminish, See for instance IIASA studies by Gunter Fischer and associates.

      • I should add that impact on agriculture under some IPCC scenarios is (slightly) negative for agriculture on a planetary scale, not because of the amount of warming in that scenario, but because SRES scenarios ASSUME a certain path of population growth. If one postulates an implausibly high growth of population over this century, one may end up with lower food per capita. But at the same time, the scenarios postularing that high population (such as A2) also postulate relatively high growth in per capita GDP, which is expected to produce much lower fertility. Since SRES scenarios separately postulate a given population growth and a given increase in per capita income, the two often contradict each other. In this sense the new IPCC scenarios used for AR5 are far superior: they consist of just an emission trajectory, not worrying about the particular combination of population, income and technology that would generate those emissions (in fact, they could be generated by a variety of conditions). If warming is high but population projection is more realistic (as in the A1F1 fossil-fuel-intensification scenario of IPCC SRES), the overall results are more positive.
        However the expected level of undernourishment (or “people at risk of hunger”), now standing at about 14% worldwide, would diminish by 2080 to just 6.8% in A2, and to about 1-2% in all other scenarios.
        References:
        Fischer G., M.Shah & H. van Velthuizen, 2002. Climate change and agricultural vulnerability. A special report, prepared by IIASA as a contribution to the World Summit on Sustainable Development, Johannesburg. Laxenburg (Austria): IIASA. http://www.iiasa.ac.at/Admin/PUB/Documents/XO-02-001.pdf.
        Fischer, G., M.Shah, F.N.Tubiello & H.van Velthuizen, 2005. Socio-economic and climate change impacts on agriculture: an integrated assessment, 1990–2080. Philosophical Transactions of the Royal Society, Series B, 360:2067-2083.
        Fischer, G., M.Shah, F.N.Tubiello & H.van Velthuizen, 2005. Socio-economic and climate change impacts on agriculture: an integrated assessment, 1990–2080. Philosophical Transactions of the Royal Society, Series B, 360:2067-2083.
        FISCHER, Günther, Francesco N. TUBIELLO, Harrij VAN VELTHUIZEN y David A. WIBERG 2007. «Climate change impacts on irrigation water requirements: effects of mitigation, 1990-2080». Technological Forecasting & Social Change, 74: 1083-1107.
        .
        FISCHER, Günther 2009 «World Food and Agriculture to 2030/50: How do climate change and bioenergy alter the long-term outlook for food, agriculture and resource availability?». In FAO 2009, How to feed the world in 2050. Proceedings of an Expert Meeting (Rome, FAO , 24-26 June 2009). . Fischer’s paper at .

      • For one, global agriculture will benefit as a whole

        Citation needed. Many studies have found the opposite.

        Existing integrated assessments of this matter indicate that food supply worldwide (total and per capita) would greatly increase as a result of IPCC projected climate change, and the prevalence of undernourishment (or “people at risk of hunger”) meaning people lacking access to sufficient and adequate food) will greatly diminish, See for instance IIASA studies by Gunter Fischer and associates.

        100% wrong. That’s a clear misrepresentation of Fisher et al’s conclusions.

        Fischer (2005):

        Current research confirms that while crops would respond positively to elevated CO2 in the absence of climate change (e.g. Kimball et al. 2002; Jablonski et al. 2002; Ainsworth & Long 2005), the associated impacts of high temperatures, altered patterns of precipitation and possibly increased frequency of extreme events such as drought and floods, will probably combine to depress yields and increase production risks in many world regions, widening the gap between rich and poor countries (e.g. IPCC 2001a,b).

        http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1569572/

        Fischer (2007):

        Coupling an agro-ecological model to a global food trade model, two distinct sets of climate simulations were analyzed: 1) A non-mitigated scenario, with atmospheric CO2 concentrations over 800 ppm by 2100; and 2) A mitigation scenario, with CO2 concentrations stabilized at 550 ppm by 2100. Impacts of climate change on crop yield were evaluated for the period 1990–2080, then used as input for economic analyses. Key trends were computed over the 21st century for food demand, production and trade, focusing on potential monetary (aggregate value added) and human (risk of hunger) impacts. The results from this study suggested that mitigation could positively impact agriculture. With mitigation, global costs of climate change, though relatively small in absolute amounts, were reduced by 75–100%; and the number of additional people at risk of malnutrition was reduced by 80–95%.

        http://www.sciencedirect.com/science/article/pii/S0040162506001417

        Fischer (2010) FTW:

        Accumulating scientific evidence has alerted international and national awareness to the urgent need to mitigate
        climate change.
        Meanwhile, increasing and reoccurring extreme weather events devastate more and more harvests and livelihoods around the world.

        http://www.sciencedirect.com/science/article/pii/S0040162506001417

      • Hector
        Thanks for the references. Further evidence for CO2 benefits is being compiled by: CO2 Science

      • “What is your evidence that radically changing the earth’s climate will directly benefit anybody?”

        Robert asking for evidence is like a breadbox asking for sequential.

        Andrew

    • Since there are no reliable models that can tell anyone what the climate will be like 50 years from now is any specific area, someone stating that they “know” a particular will benefit or be harmed is being untruthful.

      Common sense would lead any reasonable person to conclude that when the climate inevitably changes over time, some areas will benefit while others are harmed. This will be true regardless of any human impact.

      Robert’s inability to use common sense, makes reasonably communication with him ineffective.

      • Since there are no reliable models that can tell anyone what the climate will be like 50 years from now is any specific area

        Citation needed. One can say with confidence, for example, that the Arctic will be warmer.

        Common sense would lead any reasonable person to conclude that when the climate inevitably changes over time, some areas will benefit while others are harmed.

        That is not common sense; it is a half-baked belief in some sort of cosmic balance (groovy, man). In reality, there is no rational case to be made that some people will benefit if others are harmed. If that were true in all cases, some people would be better off after nuclear war.

        What is your evidence that any significant group of people will benefit?

        On a related note, have you made any progress in meeting your burden of proof in supporting your claim that radically altering the earth’s climate is safe?

      • Robert, there is a fairly large literature on who will benefit from AGW. Read the literature. Some economists may even think it will be net beneficial. Mind you they assume moderate AGW, not CAGW, which you may be assuming. I assume no AGW, based on the facts, so the issue does not even arise for me.

        As for your claim that “One can say with confidence, for example, that the Arctic will be warmer;” it is ridiculous. Climate is clearly an oscillator, so it is quite likely that the Arctic will be cooler 50 years from now, but nobody can predict anything with confidence at this point, and that’s a fact. I realize it is not one of your chosen facts, but too bad.

      • Robert

        You continue to stupidly ask for something that will never be provided and has been demonstrated to be unnecessary. You wish human behavior to change. Those who wish for a change in human behavior need to make the case it is worthwhile. Nitwits seem to have trouble grasping this simple concept.

        Some people are better off after a nuclear war (those who do clean up as an example). That does not mean it does not seem clear that there is a net harm to society (generally) from there having been a nuclear war.

        In the case of climate change there is much that is not known regarding the potential harms and there is even more unknowns regarding the benefits of taking many mitigation actions. There is no clear case for most of the actions recommended by people like you

      • Robert,
        Knutti and Tebaldi Royal Society Papers (b), and other papers with these two authors. Several others can be found, but the best is Browning and Kreiss’s work, which shows that the models cannot be correct pphysics models shortly past the startup time due to errors. Other papers, and I think it is Archiblad have pointed out the errors for models that have existed for a time to get statistics, and current models are at borderline invalidation at present. Other studies on other failing attributes can be found in the literature, but IPCC author,a physics answer, and model examinations all in the litertature, indicate that models cannot be used for local or regional estimations, and as noted above, agriculture is both local and regional in nature, with local predomnant. Also, note that the meme of increased hazards and extreme weather which is the validation of the negative articles you quoted, have been falsified at present.

      • Knutti and Tebaldi Royal Society Papers (b), and other papers with these two authors. Several others can be found, but the best is Browning and Kreiss’s work, which shows that the models cannot be correct pphysics models shortly past the startup time due to errors.

        What are you presenting these citations as evidence of?

        They appear to relate not to benefits/harms of global warming, so I tend to think you are presenting them in support of the claim that “there are no reliable models that can tell anyone what the climate will be like 50 years from now is any specific area.” But none of the papers I found seem to show that (it’s a very strong claim.) Obviously there are lots of people who feels that there is a lot of uncertainty regarding model predictions. I happen to agree with that, but that is not the same as claiming that they give us no information about specific regions. Do you have a particular paper in mind?

      • Yes, Robert you wanted citations. Given that the argument relied on the the methodology of what you argued for stating that GW would definitely cause harm, you seem to have misplaced the reasoning. Wedo not know that it will, it has not hapened yet. The arguments for you and against you involve the certainty of the models. The Royal B paper by Knutti and Tebaldi points out that on the local and regional level, we do not yet have the tools to claim as you did about “knowing.” The Kreiss and Browing papers show that the models are not truly physical, i.e. like engineer’s models that can be interperlated not extrapolated, which also show the uncertainity of caliming that certain events assoiciated with warming, not the warming necessarily itself is negative. Recent comparisons of local scenarios and world temperatures with the appropriate scenarios cast doubt on the temperature increases and their impact on the current time level. If you add recent papers on biomass and other biological positive response to inrceased CO2 and temperature that has been seen, the information indicates your claim of adverse effects cannot be established for present, future, or for the areas that agriculture actually occurs.

        Personally, either good things can happen or bad things can happen, due to the uncertainty. Biologists have measured the benefits of CO2 and temperature increases on the local level. So, it is your claim that needs to support that this will no longer be true. The models and claims to date you cited, are based on the assumptions that certain consditions will occur or exist. The citations, limited as they were, of mine indicate that such is just speculation. Thus what is known are the benefits. The level of detriment is not known nor what the local conditions are except for extrmem conditions, that even climate science has indicated are very low probability.

      • Rob –

        Some people are better off after a nuclear war

        Interesting comment. Would you mind elaborating a bit on that?

      • “Yes, Robert you wanted citations.”

        I realize you may be new at this, but in general, when one provides citations, they should relate to a specific question under discussion.

        “Given that the argument relied on the the methodology of what you argued for stating that GW would definitely cause harm, you seem to have misplaced the reasoning. ”

        How so? Global warming will definitely cause harm. None of the authors you cited, as far as I can tell, have ever maintained otherwise. If you want to claim that they have, you need to get more specific in citing a particular paper.

        “The citations, limited as they were, of mine indicate that such is just speculation.”

        No, they don’t actually say that. I think lack of familiarity with academic language may be leading you astray. “There is more uncertainty here than we previously realized” is not at all the same thing as “all other scientific work in this area is mere speculation.”

        I’d love to see a quote by the authors to the effect that everyone else is just speculating, but I suspect that is simply your (mis)interpretation of the normal scientific back-and-forth about measuring and accounting for uncertainty.

      • Rob,

        The claim that AGW will be beneficial or neutral requires evidence just as much as claims it will be harmful. In the absence of such evidence the answer is we just don’t know.

      • andrew,

        Are you familiar with the large literature on impacts?

        That global warming will, at a minimum, cost us trillions of dollars a year in the latter part of this century, is not disputed by serious people. Economists and climate scientists alike agree on it. So it’s not true that “we just don’t know” if the “we” in that sentence is indeed include scientists or economists or educated lay people. We do know. The scale of cost remains uncertain; the sign of the cost is not.

        http://bit.ly/upVb97

      • Robert,

        Oh absolutely – I didn’t mean to suggest that there was no evidence either way, merely that even if there were not we couldn’t just assume that AGW would be benign and there was no cause for concern.

  5. “the paper by Morgan and Mellon

    Ouch! :)

    (If that was a deliberate trick to see which readers are actually reading the papers before commenting on them, congratulations – it seems to have worked!)

  6. Joe and Bill, the velocity/cylinder issue is WAY off topic for this thread, which is just getting started. If you are interested in pursuing this topic, take it to week in review.

  7. ”Reducing doubt about uncertainty: Guidance for IPCC’s
    third assessment”
    by Richard H. Moss covers the reasoning and lists guidelines for handling uncertainty in climate change, as it related specifically to the TAR.

    Point #6 covers “traceability”

    Prepare a “traceable account” of how the estimates were constructed that describes the writing team’s reasons for adopting a particular probability distribution, including important lines of evidence used, standards of evidence applied, approaches to combining/reconciling multiple lines of evidence, and critical uncertainties.

    As I understand it from earlier posts, the lack of traceability remains a weakness, in particular with regard to the key statement in IPCC AR4 WG1 SPM:

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

    It is also a weakness in Table SPM.2.: “Recent trends, assessment of human influence on the trend and projections for extreme weather events for which there is an observed late-20th century trend”, where the ”magnitudes of the anthropogenic contributions are not assessed” and a large part if the attribution assessments are ”based on expert judgement rather than formal attribution studies”.

    So it appears that the guidelines are there; they just are not being followed.

    Max

  8. If a scientist uses selected tree ring data, ignoring the bits that don’t match the desired outcome, what is the value in the application of uncertainty analysis on the data?

    • Uncertainty analysis is not applied to the data but to the process. Properly done it would reveal the faults that you describe, plus others. In fact the debate between warmers and skeptics is a large scale social uncertainty analysis. It just needs to be formalized.

  9. OK, more explicitly…

    This is not a paper by “Morgan and Mellon”. This is a paper by M. Granger Morgan, from Carnegie Mellon University. It seems that somebody (editor or author ) messed up with the author/institution fields.

  10. Dr. Curry,

    Some time ago, I decided to avoid comments or comment threads in which Robert participates. Now I find that Robert is everywhere with his misdirection and I must avoid 90% of all comments. Robert is really hurting your blog. Could you please ban him?

    • here are comment stats for the past week:

      Robert 52
      P.E. 48
      David Wojick 39
      kim 38
      lurker 36
      stefanthedenier 34
      WebHubTelescope 30

      Robert is definitely the heaviest commenter for the past week, but this rate of commenting is not excessive by the standards here (in busier weeks, individual comments may exceed 80).

      While many may judge him annoying, he isn’t in violation of blog rules. If the number of comments gets excessive, I will put him in moderation to slow down his comments

      If you want to personally avoid him, I suggest not responding to his comment.

      • If you want to personally avoid him, I suggest not responding to his comment.

        Just goes to show why I’ve never doubted your wisdom, Judith.

        With that short but pithy post, you show insight that is far in advance of the string of “skeptics’ who line up to write “off-topic” comments hand-wringing about “off-topic” comments.

      • I am starting to delete Robert’s comments that are mostly free of content, his comments are dominating the thread.

      • Just eyeballing the thread, I see more arguments backed up by specific references to the peer-reviewed literature than is usually the case. Many of those citations were by me; most of the others were directed at me.

        The discussion has largely been respectful and relevant.

        If I am dominating the thread (and I assure you that was never my intention) one might argue that the thread is all the better for it.

    • John Carpenter

      Theo, Robert is a curious character. What you get from him all depends on how you engage. I am able to have a civil discussion with him just as easily as a toxic one. Once Robert enters toxic discussions, it is good to leave it alone. I find recently he is posting better, more substantive comments. Mind you, I find little common ground with the fellow, but he has a place here when he behaves.

    • Theo,

      I appreciate that Robert is an annoying pest. But a realization that Robert is a person who really needs help has allowed me to put his leg-humping antics on this blog into a perspective. So what I do, is I try to offer him a helping-hand. I mean, like, talk things over with him and offer him some good advice and that sort of thing. For example:

      “You know, Robert, there’s probably something to be said, in the past, for keeping your intellect at a reflexive, insectoid-level of functioning. I mean, your unambitious-flunky, party-line butt-kisser, harmless-hack qualities have been highly valued by your hive-masters, I know, and have gained you a coveted, cushy place at one of those lesser Big-Green troughs, reserved for useful-“Idiots” of the gofer-grade. And, no doubt, even your disturbed, creep-out weirdness is highly-regarded by your betters. A useful resource, I’m sure they see it–there, if needed to spice up one or another of their expendable-comrade show-trials, for example. So, naturally, you’re attached to your mental-midget, good-lefty modes of thought and are reluctant to “think out of the pod.” I understand all this, Robert, and am therefore tolerant of your limitations.

      But, Robert, as we both know, that whole greenshirt hustle, that has been so improbably good to you in the past, is like totally, you know, turning “tits-up”, even as we speak. So, don’t you think you might want to experiment–play around, at least–with some original thought, colorful expression, interesting discourse and all that sort of good stuff in your comments on this blog (and, hey, Robert, I’m not suggesting any such thing for your own loser blog, mind–that’s sacred ground, I know)? I mean, working your way out of the overly-specialized, eco-parasite, reliable-cog rut you’re now in just might make the difference between your future employment in a real job and the desperate life of a has-been useless-eater without a meal ticket. Think about it.”

      I dunno, Theo, this sort of thing works for me, at least. And I like to think it helps Robert, too. Not that you’d expect to notice any imprement in the short-run, of course. But in the long-rung?–well, I like to stay optimistic.

  11. “There are also a number of things about which many people are certain, but should not be.”

    Better said — “it ain’t what we don’t know what gets us into trouble. It’s what we know that ain’t so.”

    “Cognitive hubris is particularly troublesome when combined with radical ignorance.”

    “Our comforting conviction that the world makes sense rests on a secure foundation: our almost unlimited ability to ignore our ignorance.”

  12. Patrick Moffitt

    “While the IPCC has yet to make use of them, there are methods that allow an even more precise characterization of uncertainties. “Expert elicitation” involves a set of techniques first developed in the decision analytic community. ”
    It is acknowledged that there are cognitive biases at work that make this less reliable- however it has been my experience that the largest bias is in how the question was framed to the experts.

  13. we asked respondents to assess the probability that their uncertainty about the value of climate sensitivity would grow by 25% or more after a 15-year program of research at 1-billion $/year.

    But what happens when after a 15-year period observations greatly diverge from the prediction? At what point do we say that the reality invalidates the research? Reality is one thing that doesn’t seem to be highly weighted as time passes and it begins to diverge from the behavior predicted by the research.