How to talk to a climate skeptic

Wondering how to respond to that cantankerous uncle of yours who keeps baiting you with climate change denial at family dinners? Never fear, an excellent series of articles on how to deal with this very situation has been indexed and cross-referenced by Grist. Arguments are divided by stages of denial, scientific topics, types of argument and levels of sophistication. Exhaustive, and thoroughly worth checking out.

Hat-tip to Caraka for this one.

28 Comments Posted

  1. BJ – I would appreciate a link to the isotopes studies if you can find it. If we can show the CO2 is ours, then that would really clinch the argument IMO. Without it there could still be some uncertainty, but I am not as convinced it is a great as insider seems to think.


  2. The CO2 has risen to higher levels than have been seen through the last 5 ice-ages, and faster than it has ever risen by any measure we can establish by ORDERS-OF-MAGNITUDE. Temperature is the lagging indicator, like 30-50 years during a stable interglacial. So we are seeing the effects of the middle of the LAST century at this point.

    Temp precedes a CO2 spike at the end of the ice-age. The end of the ice-age is driven by other phenomena and the CO2 amplifies other signals but doesn’t by itself drive. The temperature continues to rise with the CO2 contribution added at that point… and the starting concentrations are quite low…. particularly compared to the present.

    With respect to the isotopes, those have certainly been used to good effect and we know quite clearly that the CO2 is ours.


  3. Kiore

    I think you are overestimating the certainty

    1. Not in dispute

    2. risen markedly? I think this is what much debate focuses on. It has risen, it appears to have risen out of line with recent historic values but not unprecedented in geological time.

    3. No. It is believed to be partially/significantly responsible for some/most of the change but as you point out the signal is not exact.

    4. I’m not sure that is as precise a view as that. Isn’t there an argument that the temp precedes the CO2 increase. On your question about C13 I don’t believe there’s any argument that fossil CO2 is not in old samples – I believe it has been studied.

  4. Chefen

    If the models are not actually independent then your critique is fair enough, and maybe they are all the same model. To use the smoking analogy this would be like continually sampling the same population.

    But my understanding is that atmospheric modeling is not the only metholodogy used and is not the only evidence.

    It seems the following are indisputable.

    1. Humans are putting a lot more carbon dioxide into the atmosphere since the industrial revolution.

    2. The termperature of the earth has risen markedly in the last 100 years, more so than prviously, and more than can be accounted for through simple random effects.

    3. The rise in CO2 is correlated with the rise in temperature.

    4. Ice samples have shown that there is always a correlation between CO2 rise and temperaure.

    Of course a correlation is not the same as a causal relationship, and it is possible that the termperature caused the CO2 rise, or the temperature and the CO2 rise are both caused by an unknown factor X.

    Mitigating against this however are the following.

    A. Physical chemistry predicts a rise in temperature with a rise in CO2

    B. No candidate for X has been identified. Sunspots and various other factors have been ruled out.

    C. No plausible model has been found for a way in which the temperature rise could cause a rise in CO2 levels. One that does come to mind is simply more release of CO2 from solution in the oceans, but if that was what caused the rise then the atmospheric concentration of other gases found in the oceans should also increase.

    I would like to know if anyone has studied the level of C13 in CO2 in the present atmosphere and made comparisons with CO2 trapped in the ice. If there is a much lower concentration of C13 now then that would indicate that the increase is coming from fossil fuel burning.

    As far as the “hockey stick” argument goes, it seems as if Coby is making the quite reasonable and honest admission that he does not know enought about it to say whether it is valid, so he/she will give others the benefit of the doubt and assume it is invalid. But Coby then says that the nobody needs to rely on the hockey stick because there is plenty of other evidence, which actually backs up what I said about cumulative evidence.


  5. HA

    I see the blog software has cleverly removed my xml delimiters for the fake mexican accent. This rather spoils the joke.

    One day I’m going to have to have a chat with the SW source code.

    Not today though.


  6. Chefen

    Please 🙂

    We’re in New Zealand …

    We done neeed no steeenking decisions

    …. and more seriously

    It is what it is


  7. “We rely on the fact that people who actually KNOW what they are talking about are not climate change deniers…”

    Well so long as we are all clear about how to decide who is who then.

  8. Chefen – We don’t rely on it. We rely on the fact that people who actually KNOW what they are talking about are not climate change deniers…

    Not all Greens are equally qualified at science, but you will find that there are more than a few scientists and engineers among the Greens.


  9. Well his description of chaos and its application to climate for a start, that is wrong. The “objection” it answers is itself faulty but his rebuttal makes the same error, that chaotic systems are not deterministic. The objection is bad, the rebuttal is worse, so it’s all a bit pointless. He tries to address that but doesn’t seem to understand chaos very well.

    Ditto for the hockey stick stuff, where he goes basically from “I don’t really understand it” to “well it doesn’t matter anyway”. He doesn’t even come near addressing the question of “are these actually temperature proxies?”.

    General inconsistencies, you need to read through a few of his entries and and match up the arguments, but I pointed out a few of those above. Unfortunately the RC comments don’t really say much more than ‘good work’.

    Really all I’m saying is that I wouldn’t rely on it for “defeating” someone who knew what they were talking about and sat down with the whole thing.

  10. yes and he seems to have posted responses to them all giving reasons why their arguments are wrong and linking to references that prove his point. Unless you have any evidence to the contrary?

    Also, he seems to have the support of many real climate scientists over at real climate
    (where he even asks them to keep him scientifically correct).

    So all in all, I would say that I find your characterisation of the site as inconsistent and inclusive of basic scientific errors as incorrect. Go on I challange you – what is the basic science that he gets wrong? With the emphasis on basic.

  11. if you’ve spotted some poor science on that website, I suggest you post a comment about your concerns there, Coby seems very reasonable and responsive and I’m sure he would correct anything that was wrong.

  12. Actually kiore1 you are mistaken about being able to use an ensemble of models to infer reliability in that way. They are not a priori independent for one thing. Correct models describe reality, but the problem is a model that describes reality is not necessarily correct. All these types of models do things in a similar way, parameterise variables that are not/can not be accounted and select parameters based on training against certain periods. That leads to the models converging with each other within a certain bound so the fact that they appear to agree is taken to imply someting about the reality of the system itself, but the problem is that the agreement between models does not actually imply that they are accurately describing reality. For that you must look to the construction of the models themselves, how the laws of thermodynamics are approximated, what energy transport mechanisms are included and excluded, how boundary conditions are set, how interface situations are handled, exactly what is parameterised instead of input as an ab initio value (for instance, does a parameter space search here) etc. Otherwise you might as well use a neural network to construct the models, it would work just as well, agree with other models just as well and not acutally contain any physical system description. That’s the problems with regarding an ensemble of models as equivalent to repeated trials of the true system. While in the future the modelling should only get better at the moment they are not nearly stable enough or able to justify various parameterisations as physically accurate to rely on a supposed agreement. You can talk about Bayesian probability all you like, but it doesn’t really matter here unless you can specify P(models are accurate descriptions of reality|models are not independent).

    Your mention of cumulative evidence makes the same mistake. The evidence is not independent so it is not truly cumulative.

    The tobacco thing is a straw man too. In this case you have literally millions of repeated trials of both those who smoke and those who don’t with a significant numbers of both in different categories of other possible influences. It is simple epidemiology. You are not relying on having a physical model of the cause. In the case of climate modelling you have one in-progress trial, which you are claiming is sort-of ergodic such that you can regard a collection of a few similar models as repeated trials. There is in fact very little similarity between the situations.

    Anyway, the problems with modelling are the least of the worries for that web site. Like I said, it isn’t even consistent and gets some of its basic science wrong.

  13. Garth George is a bit of a worry, he, like all of us, is entitled to an opinion, but unlike us he gets a great deal of media coverage, both written and radio. I would bet by now most people, who have read even a little bit, will decide there is always an exception to a rule and Garth certainly stands out to the far right almost all by himself. Does he have any credibility? I think not! Does he belong to any type of ‘exclusive’ church?

  14. that is a fantastic resource but unfortunately it doesn’t have a counter for the argument expressed by Garth George in the Herald today, that global warming is codswallop because God said so.

    He writes that AGW is a …

    rort being perpetrated on mankind by the well-funded boffins who tell us that all the ice is going to melt and flood the world.

    I know that’s codswallop and every time I see a rainbow I have it confirmed for me. It tells me that God is keeping the promise he made to Noah after the world-drowning flood thousands of years ago recorded in Genesis.

    “I establish my covenant with you,” God told Noah. “Never again will all life be cut off by the waters of a flood; never again will there be a flood to destroy the Earth … I have set my rainbow in the clouds, and it will be the sign of the covenant between me and the Earth. Whenever the rainbow appears in the clouds, I will see it and remember the everlasting covenant between me and all living creatures of every kind on Earth.”

    So I’ll keep on pumping gas into my four-litre Ford, the home fires will keep on burning, newspapers, magazines and books will remain my reading of choice .. and the doom merchants can prognosticate until the cows stop farting while I laugh in their faces.

    Honestly I’m speechless. What can you say to something like that?

  15. Chefen says (far more politely than he does on SirHumphrey’s)

    “He also makes the assumption that confidence based on an ensemble of models is equivalent to the confidence based on a repeated series of trials with a correct model.”

    I don’t see why there is anything unscientific about using a series of models as increasing evidence for the fact that climate change is real. It is quite consistent with a Baysian approach to scientific inference, which is after all used in formulating most scientific theories as well as what we believe in every day life, such as judgements on the trustworthiness of our colleagues. It is very unusual for a single experiment to demonstrate conclusively that some theory is true of false, the evidence is generally accumulative.

    The evidence for the link between smoking and lung cancer for example would have come from a number of epidemilogical studies, postmortem studies, molecular studies on the effects of tobacco on cells and tissue and no doubt a number of other studies I am not aware of. Probably each one of these studies, taken in isolation would offer very little proof of the link. It is the combination of all evidence that makes a convincing argument.

    It is interesting that the tobacco lobby and climate change deniers, and those advocating safety of GM crops all use the same argument. That there has been no single experiment that really proves the link. Of course there isn’t and there never will be, because nothing can ever be proved 100%. It is quite possible for example that smoking does not cause cancer, that smokers just have a certain personality type which is also linked to a cancerous personality type. It is possible in that nobody can prove it does not happen, but it is certainly not very likely.

    In the same way it is possible that global warming is either causing the CO2 build up, or that both the warming and CO2 build up are caused by some as yet unknown factor X. Again, it is possible but not very likely.

    And this is where the precautionary principle comes in. Even though we cannot prove 100% that climate change is a result of human activity, the cumulative evidence certainly supports this and we should act accordingly. On the off chance that we are wrong, well the consequences of a wrong decision would not be as disasterous as making a wrong decision if climate change really was happening.

    There are very few independent climate scientists who are still saying climate change is not happening. There are still a few, and there is still a chance they may be right. But they would need to have some pretty darn good evidence to go against the cumulative evidence for all the models that are showing climate change is happening.

  16. Ummm, while they do present some refutations of straw-man type arguments the writer really should brush up on the harder bits. For example, he doesn’t understand the critical difference between chaos and randomness. For example,

    “It is the broadly deterministic response to forcings that are of interest, and a chaotic system would not exhibit such determinism.”

    When in fact chaos arises in purely deterministic systems such as weather, that is the whole point. Chaos is deterministic.

    The section on the hockey stick is a shocker as well, going from “I don’t know much about it” to “well it’s really old stuff now so it’s irrelevant” to “well if you don’t want to use it just ignore it”…

    “If you feel it is tainted (as I prefer to just assume, because as I said I do not want to put the required effort into unraveling it all for myself) then simply discard it.”

    But then in the “Global Warming has been going on for 20,000 years.” the historical reconstructions are crucially important to the refutation. But in the end he never gets round to the nitty gritty of reconstruction methods which are heinously flawed. Shifting, variance scaling and then PCA? Jaw droppingly stupid but never mentioned.

    It gets worse of course, the Medieval Warm Period disappears because of the proxy reconstructions yet wide historical evidence to the contrary does not lead to the conclusion that the reconstruction process is flawed or the proxies are not actually measuring temperature.

    In the section ” Climate is Always Changing” he allows for very long term cycles because they are seen in ice cores but short length cycles are not allowed. But again he fails to realise that not all records can record variations equally well over all time scales. It’s like denying evolution because their are periods where fossil records are incomplete due to adverse conditions for fossilisation.

    As for the modelling, well he places much greater trust on them than the modellers themselves do and makes no attempt to explain the problems of parameterisation and neglected influences.. for example has sarcastic slides about media interpretation of results. He also makes the assumption that confidence based on an ensemble of models is equivalent to the confidence based on a repeated series of trials with a correct model. Unfortunately those situations are not ergodic.

    It’s all self-inconsistent and unscientific, why would it convince anyone who sat down and read it all through?

  17. i just had a chilling thought..

    would the green mp’s support marions’ bill..?

    (poss given her incendiary experiences with ‘sparky’..jeanette might support the idea of banning/suppressing things that can cause fires…)

    i dunno about the others..

    does anyone know..?…or is it a matter of waiting for the fireworks policy to work through the policy process..before anyone can answer that question..?


  18. oh..and next week i start advertising whoar on the ‘best little radio station’ around these parts..

    (let’s just call it (the ad) “..david lange reminiscing about david benson-pope…the early years….tee-hee..!..)

    95bfm…….(available on-line..)

    and you really should tune in for havocs’ breakfast

    7.00am(sorta) ’till 10.00am (nz time)..

    and you should really go to the 95bfm website and listen to mikey interviewing marion hobbs..(today 1st nov)..and her reasons for her private members bill to ban the private use of fireworks..!
    (feck off..!

    you will hear hobbs tell us why this bill…(apparantly a grumpy old man walked into her office one day..etc etc..
    that and a couple of anecdotals is pretty much it…whoar..!

    (go there and marvel at the vacuity..and regret those murmering words of approval you uttered when hobbs first hoved on the scene..

    havoc was particularly effective when he pointed out to hobbs the memories of his childhood etc..and fireworks..

    and my boy is 11..and he is blissed it is fireworks this wknd….and i am blissed out at him being blissed out…

    why the hell does hobbs want to take that away from us..?..and others..?

    (blo*dy miserablists..!

    but hey.!..that’s ok..hobbs said we can all go and watch community

    feck off..!

    (i don’t do big crowds…you’ll get me out for womad..but that’s about it..)

    also..havoc noted that ‘we don’t celebrate very much down here..marion.’…..

    go..listen..wonder..and ask yourself how many points this would shave off labours vote next election…..


  19. frog..that’s ‘cos i’m a feckin’ luddite…!

    these ‘magic word machines ‘ scare me…

    (i am still gape-jawed at the wonders of the ‘white mans’ magic talking wires’..the telephone….how do they squash all the words up..?..and then unsquash them again..?..)

    (and on this computor thingy..i just string the words together/find the stories)
    (and it’s good eh..?…’cos my handwriting is cr*p..)

    (and after an update/move on site….etc..etc..sigh..!..)

    but it will be on real soon…

    and i saw my new logo today…

    it not only rolls…!

    a new symbol/icon..coming to you soon..

    (tee-hee..!…the masterplan moves forward..(incrementally…)

    (…”ssooon..! precious…..soon you will fly..”..)

    ha-ha..!…(as long as yr having fun doing

    that’s what really piss*s off the sour-pusses of the world eh..?….

    when they can see you laugh at (most of) the carnival….



  20. Oh, and thanks DenMT. I think the Grist index is actually of the work that Cody has done at ‘A few things ill considered’ – so it’s the same material we’re talking about.

  21. Phil, we have a link to your site in our blogroll, and I do check it out from time to time as I’m sure many of our readers do. You certainly do link to a lot of interesting articles relevant to the Greens and environmentalism.

    I do find it interesting that given your complaints about censorship here, you choose to leave the comments function switched off on your own blog.


  22. The ‘A Few Things Ill Considered’ blog site is excellent in this respect as well. It has a section ‘How To Talk To A Skeptic’ which has a bunch of collected links on a number of topics:

    And Phil, with respect, your site seems to be links with a topic heading for each one, rather than going for the traditional ‘blog’ format whereby the blogger provides their own analysis and opinion. I don’t think you should necessarily be chastising Frog for not linking to you simply because you are ideologically similar.


  23. frog…very good to see you giving a hat-tip an ideologically sympathetic blog-site..

    and fact..that reference caused me to glance at my list of categories of stories…wondering if any of those could possibly be of any interest to frogblog readers..

    and under one of the minor categories..vegan..there are some 264 stories/links..(poss of interest to those non-carnivorous greens..or those curious about that option..?..)

    then there is new zealand politics..(also poss of interest.?)..2,454 stories/links.

    then international politics..(also poss of interest to some..?..)..3,891..

    all in all..there are a total of just under 8,000 stories/links..

    with a fresh 15-25 stories added each and every day…

    oh..i almost forgot..a ‘green’ category..(poss of interest to some?) 1,145.

    now..the next thought that came to my mind..was ..”..i wonder why frogblog never links to/mentions any stories on whoar..?..”

    then i went..”silly me…!..that question could probably have been adressed/answered in that censored thread..”


    yours in ideological solidarity..


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