Who to believe?



Amidst all the different information about climate change, how is a layperson going to know who is right? There are a few clues one could follow, that don’t require any specialized knowledge.


          Seeing the forest for the trees. Nitpicking on small details, and then claiming or insinuating that this challenges the foundation of a whole scientific field. Over-interpreting the significance of a specific finding. This is by far the most prevalent style of argument that one has to watch out for. It usually goes something like “This particular study proves that global warming isn’t due to greenhouse gases”. People tend to forget that observing a bird in the sky doesn’t disprove gravity.

–     Consensus matters. If you get a second opinion on your health condition, and it confirms what your specialist said in the first place, your trust in the diagnosis probably increases. Now imagine that you collect the interpretations of medical professionals all over the world, and by and large they their conclusions converge to the same broad picture. This happens to be how the IPCC comes to its conclusions. If the professionals do their work seriously, than the existence of a consensus amongst them is absolutely relevant (though of course it is not absolute proof). The only way in which you can ignore a consensus as being irrelevant, is if you can somehow show that the professionals are all lying or incompetent. (See the next clue for what that brings you into.) Oreskes has an excellent presentation on this.

          Beware of conspiracy theories. The consensus wouldn’t matter if somehow all those scientists had bought into the same conspiracy of wanting to take away your SUV. (Don’t laugh, there are many people who seem to think this way.)

          Timescales. Climate is defined as the average weather over 30 years. (Year-to-year variability usually averages out over 30 years). Weather and climate are very frequently confused in the popular debate.

          Spatial scales. Combined with the previous one, an example would be: “It was a very cold winter in the US this year (so global warming is a farce)”. This is also used the other way around: “It was a very warm winter in the US this year (so global warming is getting worse)”. Both are equally silly conclusions.

          Logic. Some of the most heard ‘skeptical’ arguments don’t stand up to basic logic, and no knowledge of climate is needed to see that. Example: “Climate has always changed, so it is not caused by humans.” It wasn’t in the past, but that’s no evidence that it isn’t now. Try that line of argument in a court of law against a pyromaniac, by saying that forest fires have always happened naturally; it won’t fly.

          Confusion of cause and effect. A consensus emerged as a result of the strength of the accumulated evidence, not the other way around. Activists may try to persuade you to trade in your SUV for a Prius because they’re worried about climate change; not the other way around. A tricky one is temperature and CO2: They influence each other both ways. (see also here

          Think in terms of likelihood. How likely is the previous proposition of a mass conspiracy amongst stubborn scientists? How likely is it that scientists have for decades overlooked this little finding that supposedly shakes the foundations of a relatively well established science?

          Think in terms of risk. What if we take measures against global warming and it turns out less bad than expected? What if we don’t take measures against global warming and it turns out worse than expected? (False positive and false negative, respectively. See also this comment at RealClimate) 

          Check for consistency. If someone sais (rightfully) that one particular event (e.g. Kathrina) is not proof of man-made climate change, but then claims that the current cold winter is proof against, you should raise your eyebrows.

          Expertise. In gauging the credibility of a source, their expertise is important to consider. When it concerns your health, you usually trust a doctor’s opinion more than that of a software engineer. It is not unreasonable to trust a climate scientist more than a doctor when it concerns climate. Of course this is not proof, but there is a difference in likelihood of them knowing what they’re talking about.

          Motive. The credibility of a source also depends on their motives, both on economic and ideological grounds, for telling you a certain side of the story. What vested interests, if any, are there to the different sides of the story? In a worldview where government interference is deeply hated, could it be tempting to distort evidence that could possibly lead to calls for government action? In a worldview where societal problems are preferably tackled by government, does it make any sense to make up a phony problem to call for government action? I don’t know anyone who wants government action on a phony problem just for the sake of it. Don’t underestimate the power of ideology, but always include a sanity check. See also here and here.


This list is not exhaustive, so if you have other pointers to add to make sense of the public debate on climate change, please share them in a comment. Similar issues of weeding through sources have been discussed in a number of thoughtful posts here, e.g. this one on cherry picking. Other good discussions here, here and here.


Ideally, you would critically assess the evidence for each position to form a well founded opinion on anthropogenic global warming (AGW). In the absence of time to do so, you need to take some shortcuts to assess the flood of information about the topic. None of the clues discussed here constitute proof for or against AGW, but applying multiple clues simultaneously to gauge the credibility of a source can be helpful to ‘distinguish the chaff from the grain’ (het kaf van het koren te scheiden, as we say in Dutch).



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48 Responses to “Who to believe?”

  1. jules Says:

    A nice post related to yours is this one :

  2. Aaron Lewis Says:

    1) I like trees! I think Technical Paper 5 and ice dynamics are as important as the forest in AR4-Summary for Policy Makers.
    2) Consensus has become another word for reticent.
    3) There was a conspiracy to not allow high risk issue issues such as ice dynamics to be properly researched and published.
    4) How do you tell climate from weather when the climate is tending warmer and warmer every year? (Sum of all heat, not just air temp.) Is rain every week in January somewhere in Greenland really just weather? It was driven by warm water in the North Atlantic, is a warming North Atlantic just weather? Do you expect the coasts of Greenland to reform sea ice and revert to being cold deserts as one of your Christmas gifts this year?

    Climate has become a trend rather than average of past weather. Averages have no meaning in perturbed or forced systems.

    5) . . . . . . . .
    I guess I am an extreme denialist. Now I know which camp I am in, and where to pitch my tent. I will sign up to tell alarmist stories at the bonfire tonight.

  3. Thin king Man Says:

    Bart wrote: > People tend to forget that observing a bird in the sky doesn’t disprove gravity.

    People? To whom are you referring, sir? I know no such people. And yet you’re essentially correct: it doesn’t disprove gravity. And it goes far in proving flight. Knowledge is contextual, and newly discovered truth cannot contradict old. Which is precisely why the details do matter.

    Bart wrote: > A consensus emerged as a result of the strength of the accumulated evidence, not the other way around.

    Really? Well, you’ll ideally want to back that up a little more, especially if you’re going to put it under your Logic entry. But I’ll tell you what: you sign that, have it notarized, and I’ll take it under consideration. In the meanwhile, let us not forget the propaganda campaign (paragraph four) that kicked the whole thing off. Also, you might be interested in this book, Chapter 11 in particular. You won’t like the source, of course. But you’ll like the story, I promise you — all the more, I think, in light of how strongly it supports your consensus-emerged-as-a-result-of-the strength-of-the-accumulated-evidence assertion, which you offer us, paradoxically, without any evidence.

    Bart wrote: > How likely is the previous proposition of a mass conspiracy amongst stubborn scientists?

    Friend, this is not a conspiracy; you needn’t worry about that. A conspiracy, you see, is covert, cloak-and-dagger. This, rather, is an explicit worldview, a political conviction, which, like a religious conviction, is deeply held, and in this way forms the very core of the holder’s life. That’s precisely why political conversions are every bit as dramatic as religious conversions — and, I might add, every bit as banal. What we’re dealing with here is an agenda. And for this reason, “cabal” is far more felicitous than “conspiracy” (please see below).

    Bart wrote: > How likely is it that scientists have for decades overlooked this little finding that supposedly shakes the foundations of a relatively well established science?

    By “scientists” you refer exclusively to those who propound the AGW theory, yes? I ask that only because, as you know, there are many, many scientists who don’t subscribe to that theory. Also, your choice of the word “overlooked” implies a kind of innocence, or an honestly mistaken stance, which implication many of us are not entirely comfortable with. Other than that, though, the answer to your question is very. Let us note moreover that it’s only been three decades, which is not a lot of time. Obviously, errors of unanimous scientific consensus have lasted much longer than that. Beware the fallacy of insufficient evidence, which I discuss in more detail here.

    Bart wrote: > What if we take measures against global warming and it turns out less bad than expected? What if we don’t take measures against global warming and it turns out worse than expected?

    Yes, this well-known notion was once called Pascal’s Wager, and it is closely related to the Precautionary Principle, both bunked a billion times over, as, for example, when I was recently told: “It’s nice that an administration is actually going to listen to scientific advisers like the National Academy of Sciences. It’s about time.”

    My response: It’s about time for what, exactly? The state to regulate industry? Time for the federal government to assume control over private property? Time for the economy to be determined not by the free-market and the voluntary exchange of goods and services — which, incidentally, systematically bars force from human interaction — but by bureaucratic decree and rule by special interest?

    Time to dispense with America’s foundational premise that we each possesses the right to our own life, liberty, and property?

    Time to do away with the notion that rights are inalienable in the literal sense of the word and therefore cannot be transferred or revoked? That anyone who attempts to do so is in the wrong?

    Time to grant government bureaucrats legitimate authority over the person and property of the individual?

    Time to do away with the United States Constitution, the Fifth and Fourteenth Amendments in particular, and replace it with centralized power?

    Time to forget that pollution and waste disposal require not coercive but technological solutions, and that laissez-faire capitalism, with its vast technological superiority (via the profit motive), is the only political system that’s able to provide those solutions?

    Time to ignore that when the market is free and private property rights are iron-clad, individuals and business owners have incentives to pollute as little as possible — whereas government officials have no such incentives at all?

    Time to ignore that existing environmental laws have become so complicated that only about “30 percent of corporate counsels believe that full compliance with environmental laws is actually possible” (this according to a survey conducted by the National Law Journal)?

    Time to forget that long before the so-called Clean Air Act of 1970, as the EPA itself has admitted, “from 1950 until 1970, the amount of volatile organic compounds and carbon monoxide in the air fell by more than 20 percent, even though total vehicle-miles traveled in this country rose by 120 percent, from 458 billion to 1.1 trillion. The level of sulfur dioxide in the air began falling as far back as 1920, and the total amount of airborne particulate matter has been reduced by 79 percent since 1940?”

    Time to dispense with the incontrovertible fact that no government and no governmental bureaucracy in the history of the world had ever proven itself capable of regulating complex economies?

    Time to forget that because we will live completely now in a country that is not any longer ruled by the primacy of individual rights, including, of course, inalienable private property rights, we are now at the mercy of competing special interest groups and lobbyists? That this horrific spectacle of special-interest governing is precisely what you call for when you call for government to solve our pollution and putative climate problems?

    Time to ignore that nuclear power, the cleanest, most abundant, and most ingenious form of energy we’ve yet discovered, is for all intents and purposes forbidden by environmentalists and their lobby groups, and, since 1979, anti-nuclear groups have brought the world 400 million more tons of coal used per year, because for thirty years now, since the Three Mile Island accident, we’ve been using more coal?

    Time to continue ignoring that the meltdown of the uranium core in 1979 at Three Mile Island was so overblown by anti-nuclear groups that it went virtually unnoticed how the containment vessel at Three Mile Island had done its job and prevented any significant release of radioactivity?

    Time to ignore that government bureaucracy and the rule of environmental special interest groups have directly and demonstrably caused more pollution through its adoption of coal over nuclear, and it has done so by stupendous amounts, which the free market, through its natural adoption of the most efficient option, would have abolished long ago, had laissez-faire capitalism been permitted to operate as it by definition will: i.e. freely?

    Time, finally, to ignore the fact that after nearly forty years of regulation the EPA is still unable to produce evidence that its efforts have independently improved air quality?

    One might also note that pollution problems are in fact not created by the absence of government regulation: they’re created, as the nobel-prize-winning economist Ludwig von Mises was among the first to note, “by a lack in savings and investment,” and that as long as the capital base of any society remains primitive, the means to deal with societal issues necessarily remains limited.

    One might note furthermore that laissez-faire capitalism, as its name implies, generates far, far greater capital than any form of statism, and that wealth brings cleaner environments. Wealth brings new technologies. Wealth brings cleaner food and water. Wealth brings longer life. Which is why underdeveloped countries (where, incidentally, fewer people drive cars) are more polluted, use dirtier, less efficient fuels, and destroy more woods and wetlands than industrial countries.

    Bart wrote: > The credibility of a source also depends on their motives, both on economic and ideological grounds, for telling you a certain side of the story.


    Bart wrote: > In a worldview where government interference is deeply hated, could it be tempting to distort evidence that could possibly lead to calls for government action?

    Yes. Therefore we institute laws that strictly limit governmental power, which is inherently dangerous because it possesses a legal monopoly on force over the citizens. Thus in a society where negative rights are (correctly) protected — which is to say, in a society wherein negative rights are regarded as inalienable in the literal sense of the word — distortion on either side of the argument doesn’t affect anything one way or the other because the person and property of each and every individual is fully secure, i.e. protected by law. Which is just as it should be. No government and no governmental bureau has legitimate authority over the person and property of anyone. The moment you say that they do, you’ve conceded the principle of inalienability, and you’ll never again be able to defend justice, because you’ve conceded the foundation upon which all justice is built: the inalienable right of each to his or her own person and property. And that’s the end of it.

    Bart wrote: > In a worldview where societal problems are preferably tackled by government, does it make any sense to make up a phony problem to call for government action?

    Preferably to whom? What kind of an assumption is that? But, no, to answer your question, it doesn’t make any sense at all. Which is why the entire AGW campaign is so nonsensical.

    Bart wrote: > I don’t know anyone who wants government action on a phony problem just for the sake of it.

    Well, please let me give you a few quick examples then:

    In response to this Popular Science article, in which a number of scientists and entrepreneurs proposed relatively simple, low-cost measures that might be taken to combat global warming, Greenpeace responded thus:

    “I don’t think these geo-engineering fixes are going to work. There are only two ways that we’re going to solve climate change: reduce the amount of energy that we use and dramatically change the methods we use to generate it.” According to Scientific American, environmental groups are united in the belief that “if society relies on techno-fixes to ameliorate global warming … people will stop putting in the hard work necessary to cut carbon emissions.”

    And there you begin to glimpse not the conspiracy but the previously mentioned political agenda.

    Please remember also the shrill environmental opposition to nuclear energy, which opposition has abounded for much longer now than AGW theory. That opposition, incidentally, as I also mentioned above, is directly and demonstrably responsible for bringing the world 400 million more tons of coal per year.

    Here’s a little more since you are fortunate enough to not know anyone who thinks this way:

    (edit. Please refrain from copying and pasting pages of material from your own blog)

    Obviously, I’ve barely scratched the surface, and if you’d like more such quotations, please e-mail me.

    In closing, as a polite suggestion to you, sir, you might in future consider updating your list above so that you can include a mention of the utter unwillingness of AGW scientists to openly and publicly debate this issue, which, as philosophers and thinkers have known for centuries, is the best way to promulgate the truth. That deafening silence we hear coming from the AGW corner speaks volumes and volumes and volumes and volumes, and the public understand this, implicitly or explicitly. You people who believe so fervently in your AGW cause should be urging your scientists daily to debate daily. You should tell Al Gore not to duck out of his scheduled debates with Bjorn Lomborg at the last moment. You should tell Jim Hansen to debate Patrick Michaels in public. Instead of beclowning themselves by preaching only to the converted, and speaking in propaganda forums, these scientists should be all the time laying out their case passionately, in public debate, day in day out. That would be the best way to make the case and further your cause. You might finally include that on the very rare occasions when such debates have taken place, the skeptics have easily won.

  4. Eamon Says:


    good piece, concise and well written.

    Thin king Man,

    poor response, long, wandering and considering you claim to be talking about science – very unscientific. The pages you link to on your blog, are, sadly similar.

    Also, if you had looked at Bart’s site for a moment you could have discovered that he is unlikely to be an American as he posts in English and Dutch (or a Dutch-related language). So, in all probability (note the scientific use of that word) your comments on the US Constitution are irrelevant.

  5. Bart Says:


    1) I like trees too! But the removal or addition of one tree to a forest doesn’t dramatically alter the forest.

    2) You may be right that the consensus position tends to be somewhat careful. Scientists usually try to prevent overstatement more so than understatement. At least in overview (sections of) papers and review exercises (such as the IPCC) this seems to be the case. Individual papers may be different, as they sometimes do more effort to “sell” their particular conclusion to gain more visibility and citations. Which again is why the forest is more important than the trees.

    3) In the IPCC the influence of ice dynamics was not incorporated in the estimate of sea level rise, because they deemed that not enough was known about it. You can disagree with that decision (as I do), but a conspiracy…? Come on, be serious.

    4) That’s a good point. I’ve heard Myles Allen say that the current climate is in effect unknown, because we don’t know what the next 15 years will be like. He went on to define climate as the chance of certain weather. Even though one particular event can never be blamed for 100% on climate change, its chance of occurrence may very well have been influenced by it. Which is exactly why I think it is better to think in terms of likelihood.
    In a perturbed or forced system, the average is slowly changing, and that is definitely meaningful. E.g. looking at the smoothed temperature trend rather than the daily temperature variations helps one see the forest from the trees. Tamino has numerous posts visualizing that point.

  6. Bart Says:

    Thin king man,

    “People tend to forget that observing a bird in the sky doesn’t disprove gravity.”
    I’m referring to people who grasp as the flimsiest straws and claim that these somehow prove that greenhouse gases hardly cause any warming. Exactly as you say, new evidence doesn’t replace old evidence; it merely adds to it.

    Regarding the relevance of a consensus, and how it came to be one, I provided a number of links to back up my position, notably Oreskes

    It seems that we agree on the importance of political convictions, but interpret it quite differently.

    As most of us know, there are only very few climate scientists who claim that greenhouse gases don’t have a significant effect on climate. And the evidence to back up that position is thoroughly lacking, not to mention that it contradicts basic physics known for over 150 years.

    You list a range of strange propositions (each starting with “time to…”) that you implicitly claim people concerned about climate change want. I don’t want to “grant government bureaucrats legitimate authority over the person and property of the individual” or to “do away with the United States Constitution” (I’m from the Netherlands by the way, not the US). This is all a huge straw man argument.

    If you’re so concerned about economic effects of mitigation (which you seem to be), then why don’t you contribute constructively to a discussion of how to mitigate climate change in ways that minimizes negative impacts on the economy? (And maximizes positive impacts, of which there are also many.) Absorption of infrared radiation by greenhouse gases doesn’t go away because you don’t like the perceived (and wildly exaggerated) economic consequences. Deal with it.

    Trying to reduce global warming is not a ‘political agenda’; it’s sensible politics based on scientific evidence.

    You then come along with yet a longer list of extreme opinions, insinuating that those who want to reduce global warming are all lunatics (straw man number two). It seems a little redundant to copy and paste such a long list from your own blog here, so I deleted it from your comment.

    Regarding debates between scientists and ‘skeptics’: James Hansen has debated Pat Michaels, see e.g. this transcript . It is a catch 22 though, whether to engage in these kinds of debates or not. If scientists don’t, they are blamed of being afraid of discussing their ideas. But they are not. You are welcome to join academia and contribute to gaining and assessing knowledge. Scientific evidence is continuously being discussed in scientific fora (journals, conferences, etc). A public debate is not an effective way of finding out what is more likely true or false. It is however an effective way for an unscientific viewpoint (such as creationism or climate ‘skepticism’) to gain traction in the public mind, and make the public believe that there is real scientific controversy where in fact there isn’t. It’s much easier to express a misleading one-liner that supposedly sheds doubt on some well established theory than to counter it. Public debates are primarily meant as entertainment, while they serve the interest of unscientific viewpoints and of the better debater (which scientists by and large are not).

  7. Richad Mercer Says:

    Thin King Man

    You and others who think that nuclear power is some kind of magic or siver bullet to energy and environmental concerns are just plain wrong.

    Prices for power from new nuclear plants are estimated at least 12-17cents/kWh. One recent estimate is 22-30 cents.

    Wind is about 7-8 cents/kWh and has the lowest carbon and land footprint of any energy source so far. Yes wind only uses about 2 1/2% of the land where it is sited, allowing it to co-exist with agriculture, or even solar farms on the same land.

    Solar thermal (CSP)with heat storage can meet the 12-17 cent price right now, and will fall to below 10 cents in five years and to 5-8 cents in 10 years or less. And CSP with molten salt heat storage, which is so low tech we could have done it 100 years ago, can provide steady base load power day and night. And CSP, when water cooled, can even desalinize seawater or be combined heat and power.
    And using less than half the land now used for coal mining and coal plants, solar thermal could replace every coal plant in the country. And with far less impact on the land it uses.

    PV solar will be as cheap as solar thermal and wind will be in ten years.

    In ten years you might see the first new nuclear plant come online with it’s 1 GW capacity. New technology for nuclear might be ready by then to even start building nukes. Thorium sounds promising, but again it’s at least a decade away. Meanwhile we could build 200 GW of solar and wind, while we are waiting for new nuclear tech to be tested and planned.
    Even China is planning 100 GW of Wind by 2020.

    Nuclear power is a stepping stone to nuclear weapons. There is no denying that. Otherwise, why are we worrying about Iran? Now imagine that all over the world.
    Ok, maybe thorium is different.

    The Argonne National Lab says an airliner crashing into a nuclear power plant can cause a complete meltdown, even if the containment building isn’t compromised. Terrorist targets anyone?

    Arguments like ” I live near a nuclear power plant and it hasn’t harmed me” are the equivalent of saying you live next to an active volcano but it hasn’t hurt you yet. Yet! Given that humans are prone to errors, there can be no guarantee of safety of such dangerous undertakings. We’ll never have any oil spills or coal fly ash sludge spills right?

    We import 90% of our uranium, with Russia lined up to supply 20%. How is that energy independence?

    Nuclear requires huge amounts of cooling water. How do you guarantee the supply in a changing climate? Water is already the next big problem for the world.

    Nuclear power industry has passed the liability onto the taxpayer.

    Nuclear has been heavily subsidized for 50 years, not quite as bad as oil at 90 years.

    Oil gets $39 billion a year by the way. Coal $8 billion. That’s before the new subsidies for “clean coal”

    Solar and wind can be built in a third the time of nuclear.

    For example.

    The U.S. added 8.3 GW of wind power in 2008 the equivalent in kWh of 3 nuclear plants in one year. or 5-6 coal plants.
    China added over 6 GW of wind power in 2008.
    And this is just the beginning of the growth. It should accelerate from here, solar too.

    I’m not saying nuclear can’t play a part in the future, just that your sweeping generalizations are just that. Nuclear may be a mid term solution but is not something we should be throwing commercialization money at now. research $ yes.

    “….. based on the most optimistic future projections of nuclear power construction times of 4–5 yr and those times based on historic data, we assume future construction times due to nuclear power plants as 4–9 yr. Thus, the overall time between planning and operation of a nuclear power plant ranges from 10–19 yr.”

    “The median construction time for reactors in the US built since 1970 is 9 yr.”

    “For CSP, the construction time is similar to that of a wind farm. For example, Nevada Solar One required about 1.5 yr for construction. Similarly, an ethanol refinery requires about 1.5 yr to construct. We assume a range in both cases of 1–2 yr. We also assume the development time is the same as that for a wind farm, 1–3 yr. Thus, the overall planning-to-operation time for a CSP plant or ethanol refinery is 2–5 yr. We assume the same time range for tidal, wave, and solar-PV power plants.”


    Here’s how moving to renewables and efficiency works in the real world.

    “California, the perennial best in show, has invested heavily in energy efficiency for years, creating over $3 in economic return for every $1 invested. Next Ten, one of the nation’s leading think tanks on green collar job creation, reports that over the past three decades over 1.5 million full time jobs have been created in the clean tech industry in the state. Total payroll for this pioneering green collar industry is now $45 billion, and the sustained investment in efficiency has saved Californians over $56 billion in energy costs. All this while the state has achieved a remarkable goal—no net increase in per capita energy use over the last 30 years”


    From what I understand, and others can correct me if I’m wrong, but most basic research in every field of science is paid by the govt. at least partially. Yet deniers would have us believe that govt science is bad science or shows collusion or follow the leader thinking. Of course they conveniently ignore who funds the psuedo science of the denier camp. Fossil fuels, the largest economic enterprise in the history of the world with lots to lose in the new energy economy.
    But we can trust them right? Just like the tobacco industry, who used many of the same scientist deniers like Fred Singer and propaganda mills like the Heartland Institute.

  8. Rhian Salmon Says:

    great post, Bart, thanks…. concise, clear, good crisp guidelines.

  9. Steve Reynolds Says:

    Just following your link from Fuller’s blog.

    Your guidelines are reasonable as far as they go, but seem very one sided. How about adding some to help sort overly alarmist claims from supported science?

  10. Bart Says:


    I think these guidelines don’t necessarily have to go one way or the other. Logic, timescales, likelihood, consistency, etc; they can be abused in either direction of disguising the problem or making it seem worse. Most of the examples I gave perhaps go one way, but that’s a reflection of what I see are the most egregious mistakes being made.

    But what about this one:

    “Spatial scales. Combined with the previous one, an example would be: “It was a very cold winter in the US this year (so global warming is a farce)”. This is also used the other way around: “It was a very warm winter in the US this year (so global warming is getting worse)”. Both are equally silly conclusions.”

    I actually got ‘blamed’ for saying this from the other side as well, see Aaron Lewis’ comment above.

  11. Steve Reynolds Says:


    Aaron’s comment seemed pretty incoherent to me; I could not tell if he was blaming you or not.

    I came up with a few more guidelines that I think help sort which sources to believe and generally apply to both sides:

    Propaganda: even in making true statements, only mentioning points favoring one side, never acknowledging any information that might give the other side some support. Issuing press releases with misleading statements not supported by actual research.

    Transparency (lack of): not providing full disclosure of all data and methods; stonewalling efforts by outsiders to obtain details needed for replication with flimsy or hypocritical excuses and bureaucratic delays. Making reasoned debate difficult by suppressing discussion of valid issues.

    Hypocrisy: calling for sacrifices from others that you ignore, hide, or even flaunt in your actions.

  12. Marco Says:

    Steve Reynolds,
    Let’s then also add

    1. Hiding facts: E.g., claiming you have been stonewalled, while you had the data all along

    2. False appeals to lack of transparancy: E.g., demanding you get data that is not necessary for the point that is made in the article (that is, the analysis could be repeated with any dataset)

    3. Failure to learn: E.g., making reasoned debate difficult by constantly repeating long-debunked points

  13. Bart Says:

    Your first point makes good sense, and it has indeed been violated in both directions.
    The second is partly addressed by Marco. There’s a lot to be said about data sharing and openess, but overall, complaints in those respects don’t strike me as sincere at all (sincere in terms of a desire to help our understanding of the science).
    The third really has not much at all to do with how good the arguments really are. It may lower the credibility, but not so much on rational grounds.

  14. Steve Reynolds Says:

    Well, I see Marco has no intention of being even-handed here.

    Bart: “…complaints in those respects don’t strike me as sincere at all (sincere in terms of a desire to help our understanding of the science).”

    While I disagree about sincerity, does that even matter? When I (and many others) see this lack of transparency, it makes me have grave doubts about the quality of the science involved. I understand that there are selfish professional reasons for researchers to keep their data and methods somewhat secret, but it is hypocritical to claim AGW is a serious crisis and behave this way. Not only does it potentially impede progress, but it hurts the credibility of the AGW science (which are not good things IMO).

  15. Marco Says:

    Steve, I did not intend to be even-handed, because I could see you brought in complaints that have been dealt with and *are not even-handed*.

    You complain about lack of transparancy, but clearly direct that solely at some perceived lack of transparancy that wasn’t there. McIntyre had the data Briffa used, FOUR years before he started complaining that Briffa did not want to give it to him. Why did that not cause you to have grave doubts about Steve McIntyre? After all, if anyone was not transparent, it was Steve McIntyre!

  16. Bart Says:

    Numerous people, including Briffa himself, Marco just here, and myself in two posts a few weeks ago, have explained that McIntyre had the data all along, and was barking up the wrong tree on top of that. McI is not only taking the scientific importance of his findings out of proportion, but also the level of transparency and stonewalling. The credibility of scientists is only hurt for those who already were suspicious of AGW (for whatever (usually non-scientific) reason) or those who are gullible enough to believe McI on his word.

  17. Steve Reynolds Says:

    “The credibility of scientists is only hurt for those who already were suspicious of AGW…”

    Since everyone that does not base their view of the world on faith should be suspicious of claims made based on unrevealed data and methods, I hope the credibility of these ‘scientists’ is hurt with nearly everyone.

    Note that I think the ‘scientists’ above are a small minority.

  18. Marco Says:

    Would those “unrevealed data” include the data that McIntyre had SINCE 2004? Would those “unrevealed methods” involve the analysis method that Briffa described in Science, which McIntyre repeated (notably with the data he supposedly did not have) and where this same McIntyre essentially got the same result?

    In my own field of science at least 90% of the data shown has gone through a variety of procedures that are often described in insufficient detail for a newcomer to repeat the analysis even when given the raw data. And don’t even expect to get that data. If you have any doubts on the data, you do an analysis yourself, including the data collection(!), or compare the results to other papers in the literature. Problem is, of course, that you’d have to know what you are doing, and not pick some kind of data set without knowing, or even testing, whether it is an appropriate temperature proxy. And McIntyre can’t even claim ignorance on the divergence problems and having to have a good procedure to select data sets. After all, he’s attacked Mann 08 for its supposed uncritical use of a problematic data set…

  19. Steve Reynolds Says:


    I doubt you are accurately characterizing McIntyre’s efforts, but that is irrelevant to the point.

    Your experience is a little more relevant, and that may (or may not) be acceptable in your field, but it clearly (to me at least) is not acceptable when trillions of dollars are at stake.

    >If you have any doubts on the data, you do an analysis yourself, including the data collection(!)…

    I suppose you think that when UAH analysis was questioned, RSS should have launched their own satellite?

  20. Marco Says:

    Steve, my characterisation of McIntyre’s efforts come directly from the horse’s mouth: McIntyre admitted to having the data already in 2004, admitted to having done the same analysis with the data as Briffa, and admitted to getting mostly the same result. His excuse? “I was not sure it really was the same data”. And thus he kept demanding Briffa gave him “the data”. And it *is* relevant, since you claim it is the supposed refusal of sharing data that is hurting people’s belief in the credibility of the scientists.

    Of course, the whole hockey-stick issue is mostly irrelevant to AGW (apart, perhaps, in the perception of some people) anyway.

    Oh, and your reference to UAH and RSS is rather misguided. BOTH use data collected by another organisation who just happens to distribute it freely to those who want to use it.

  21. Steve Reynolds Says:


    You seem rather obsessed with the question of McIntyre’s possession of one particular data set. Do you claim that Briffa, Jones, and other scientists have been perfectly willing to share all their data used in published papers?

    “Of course, the whole hockey-stick issue is mostly irrelevant to AGW…”

    I will agree that it is mostly irrelevant to proving AGW exists. But it is relevant to understanding climate and to evaluating the credibility of certain climate scientists.

    “BOTH use data collected by another organisation who just happens to distribute it freely to those who want to use it.”

    And you seem to think it would be fine if UAH (for example) had a monopoly on this data?

  22. Marco Says:


    You’re the one who is so obsessed with the credibility of scientists, and then try to step over the fact that one such scientist claimed for years(!) that he could not get data from Briffa, data that wasn’t Briffa’s anyway, while he already HAD that data in his possession. Please explain to us why the self-styled debunked of hockeysticks is beyond the credibilitty criticism you aim at others?

    The issue is quite simple: Briffa told McIntyre that it was not his data, and that the request should be sent to others. Briffa even forwarded that request, clearly indicating that Briffa himself was willing to share the data. Also the HADCRU data discussion has been portrayed by the deniosphere with a complete and utter failure to understand data ownership. They simply do not own the data, but have been allowed to use the data in further analyses. Regardless, as Phil Jones already remarked: with the published data and methods, ANYONE can actually calculate the raw data.

    In many other cases the practicalities of archiving the data so that others can use/understand it, is also easily overlooked. I myself have a few huge excel files, which I understand (fortunately) in all details. If I’d had to archive it so that others understand it without first getting a lengthy explanation from my side, it will take me at least a week full-time work. And that would be on top of my teaching obligations, meetings with my Master students, PhD students, postdocs, and collaboration partners, travel to conferences, etc. etc. etc. You might expect me able to get it understandable and usable by others at best a year from the moment I start working on it. It isn’t that different for many other scientists who work with large datasets.

    And the hockeystick is at this moment still of very limited relevance to understanding climate, since we know too little about the various forcings, and since we almost exclusively have land-based proxies that are relatively poorly distributed over land. I don’t see how it would in any way affect the credibility of “certain climate scientists” if there are different viewpoints on some of the methods being used. Especially when some of that criticism is outright wrong (McIntyre’s complaint about not using a data set in Briffa, a data set which actually shows a clear divergence problem), only affects details (McIntyre’s criticism of Mann 98,99), or at best is a contentious issue already discussed in the paper itself.

    Finally: it would be fine with me if the *owner* of the satellite network had a monopoly on this data. Or rather, that using its data would involve a collaboration with the people owning the data. I’m not a big favorite of collecting data that others can then freely use, since many data sets contain much more information than is initially extracted. It would give others a chance to just publish work without ever having to do the hard work. All they need to do is ‘borrow’ data others have collected. Also, and to a similar extent as HADCRU, I have contracts with collaboration partners that outright prohibit me to share data without their express approval. Which can take many months if they decide there’s a patent hidden in that data.

    In some cases it makes sense to share the data, e.g. when the owner does not have any scientific intent with the data (it is a kind of service provider), or generates so much data it will never be able to analyse it all. That’s actually the case with the satellite data.

  23. Steve Reynolds Says:


    I’m not saying anyone is beyond criticism. I’ll also not waste time debating he said/she said arguments. People can read ClimateAudit if they want that side.

    Of much more interest is your attitude toward ownership of data. If you are being funded by a government agency (especially U.S. government), I don’t see how you can claim to ‘own’ the data you acquired. Don’t the terms of your grants say otherwise?

    Even if you are not required to share your data, if you are working in the climate field, don’t you feel hypocritical about selfishly withholding this data while claiming we must immediately make critical policy decisions?

  24. Bart Says:


    “Don’t the terms of your grants say otherwise?”
    No, they don’t.

    “don’t you feel hypocritical about withholding this data”?
    No, I don’t. If through your own analysis you come to certain conclusions and report your work (incl how you reached said conclusions), then it’s available for the community. Other scientists’ energy is much better spent trying to independently investigate the same research question rather than checking my arithmetic or doing the exact same thing. And if checking of details is needed, then many would be loathe to let it be done by someone who abuses it in for political/ideological purposes rather than for the prupose of advancing science.

  25. Marco Says:

    I think Bart just about said it all. Giving my data to someone who has as his life motto the attack on every little detail that may be considered wrong (note the “may be”), without ever doing any original research, and in the full knowledge that all of his grandstanding is translated into even more grandstanding and claims of fraud…no thanks.

  26. Steve Reynolds Says:

    Well, you guys are certainly in agreement, but I am appalled by this rejection of a key ingredient for the scientific method to resolve this kind of issue in the needed time frame. There can be no excuse for keeping climate data and methods secret. It is not science if you can choose who checks your work.

    You may think you are defending yourselves from ‘claims of fraud’, but in reality, you are encouraging those claims by making it look like you have something to hide. And remember, I’m saying this as someone mostly on your side in the AGW debate.

    Since this appears to be on-topic at Peilke Jr’s blog now, I’ll continue the discussion there.

  27. Marco Says:

    Yeah right, mostly on “our side of the AGW debate”, and then vehemently defending the false claims of keeping data and methods secret. Do I really need to repeat the fact that McIntyre had the data Briffa used for FIVE years already? Do I really need to repeat the fact that you cannot blaim Phil Jones for not handing out data that is owned by commercial organisations?

  28. SUN GOD Says:

    It’s the sun stupid!

  29. Bart Says:

    The sun, it’s still number one.

  30. Tom Fuller Says:

    Hi Bart,

    I’ll take a stab at this. First, look at who we have trusted in the past. We trusted those made pre-eminent by their peers. Most didn’t understand Einstein, Hawkings, Feynman, but they believed that scientists had elevated them for a reason.

    Second, look at how those who were promoted to a position of public trust (in the real, not political, sense of the word) used their fame. In a word, sparingly. They spoke of humility and humanity and did not make arguments from authority–indeed, they often made arguments against authority. And when they spoke, the scientific community listened.

    I wonder if it’s possible for such figures to arise anymore. Science is now inextricably tied up with public policy and intellectual property, meaning there are opposing sides for everything. Look at what happened to poor old Freeman Dyson when he offered his opinion on global warming. The man is brilliant–and yet he got dragged through the gutter as if he were Rush Limbaugh or Viscount Monckton.

    All of the tips and tricks you offer are a poor substitute for what you scientists are supposed to be doing, putting impossible responsibilities on the public. Since you want to tell non-scientists what to do, here is what I call upon scientists to do first:

    1. Lead with uncertainty–always, always start with a look at error bands.
    2. Proceed with humility.
    3. Stick with the science. If you have an opinion, offer it through a pseudonym. Leave solutions to engineers and policy to the political arena.
    4. Be the first to show the weak points of your theory. Scientific papers used to call for further research in areas where existing knowledge was inadequate. Now, not so much.
    5. Don’t paraphrase for the public. Say it plainly if you can, but say it. Don’t use metaphors, similes or hyperbole.

    If you scientists were to do that, we in the public wouldn’t need your list, would we?

  31. Tom Fuller Says:

    Oh, and Marco, you’re full of it. McIntyre got burned once by using data that Briffa said was okay and then Mann said was not. McIntyre had several iterations of the data but did not know which one had been used in the report.

    And you obviously know this. As usual, you sob’s will try the same lie over and over again until someone busts you on it. The truly sickening thing is that you will repeat this somewhere else until someone busts you again.

  32. Bart Says:


    Thanks for your feedback. I’m not sure if Iunderstand what you mean by

    “All of the tips and tricks you offer are a poor substitute for what you scientists are supposed to be doing, putting impossible responsibilities on the public.”

    You proceed with what you think scientist should do. I think your points are valid, but the reality of extra-scientific attacks on the science makes it extremely hard to follow those to the letter. In the wider context of people not liking the scientific message, trying to find fault with it to provide comfort from that message, and, which is the topic of this post, often being genuinely confused as to who they can trust on a scientific topic with politicla consequences (such as climate or health).

    To the last point you haven’t responded, except by giving examples from the past who were great science communicators. Failing those, how does, and how should the public decide who to trust? I think it’s difficult to overestimate the importance of that question.

  33. Tom Fuller Says:

    Bart, you’re correct. I would suggest that what happens is actually a process of exclusion. Scientists (and communicators trying to act on their behalf) are given a certain amount of trust to start with. How they use or abuse that trust is digested fairly quickly and opinions form about their reliability. Those opinions become very hard to change.

    I think it works that way with me. I do give people the benefit of the doubt–you’ve seen me try to engage with people like Michael Tobis, etc. People like you, who ‘play fairly’ retain my respect. People like Eli Rabett do not. And I would submit that, based on the communications and other writings of the people involved, that my opinions are serving my interests correctly.

    I think most of the problems your ‘side’ has right now are entirely self-inflicted, and caused by people like Joe Romm–why on earth do climate scientists let jerks speak for them?

    Non-scientists use proxies for integrity. Hypocrisy (Al Gore’s energy consumption), condescension (Every time Joe Romm puts pen to paper), flag-waving (Michael Mann’s defense of Tiljander), insults and appeals to authority (too many examples to cite) result in a baffled, resentful and mistrustful public.

    I would suggest you look at what people do to lose trust rather than wonder how people gain it.

  34. Marco Says:

    Tom, YOU are the one who is full of it. McIntyre had the data. He *could* have asked Briffa if he indeed had exactly the same data. But he didn’t. He just kept bugging Briffa for the data!

    Of course, your last post here is another example of how full of it you are: the insults flying out from sites like climateaudit and wattsupwiththat(“Fraud! Fraud, we say!”) without *any* proof, or downright data manipulation is shocking. But you defend them as if your life depends on it.

  35. Bart Says:


    “my opinions are serving my interests correctly.”

    What are your interests that you’re referring to here?

    Note that most pointers in this post are not about assessing the person, but rather about assessing their argument: Do they provide the larger context? Is their conclusion commensurate with the significance of their finding? Does it stand up to basic logic?

    You seem to put an awful lot of weight on assessing the person, which for a scientific argument is not a valid proxy I’d wager. Perhaps you just don’t like scientists ;-)

  36. Dick Veldkamp Says:


    Here’s a couple of more (random) clues for detecting BS in the climate debate (none of them foolproof by itself of course, but good for preliminary screening)

    1. Is the opinion (article, etc) boring and written in a rambling, incoherent style? Surprisingly often rubbish is presented this way. It is like the inability of the authors to think straight spills over in their writing.
    2. Are there ad hominem attacks? In that case, it is probably not worth reading the thing.
    3. Are the claims presented extreme? For example Lomborg claims that all environmentalists are 100% wrong everywhere, all of the time. Does such an extreme claim strike you as likely?
    4. Does a claim fit in with the way the world works? Re the “environmentalists’ conspricay”: who do you think has more power to influence policy: Greenpeace or Big Oil?
    5. Reasonableness: if ALL scientific societies of the world state there is a problem, how likely is it they are ALL wrong and some deniers are right? If you are not convinced by this, when will you ever be?

    Greg Craven (wonderingmind42) has some insightful things to say about credibility (see Youtube).

  37. Raven Says:


    Looks like my response on RC won’t make it through moderation (surprise, surprise).

    Your list is the typically mishmash of alarmist talking points that avoids the real problem: groupthink and noble cause corruption.

    i.e. if a group of people honestly convince themselves that bad things will happen then they become willing to collectively justify a lot of other less-bad things in order to prevent it from happening.

    Everything I have read and heard over the last few years convinces me that this is serious problem in climate science and the entire field has become trapped in a self re-enforcing death spiral because so many scientists and politicians have committed themselves to the cause and they risk total humiliation if they backed off now.

    You also make the mistake of framing the question as a one or the other question. i.e. I have come to conclude that climate scientists are generally not trustworthy but that does not mean I automatically trust anything a self described sceptic suggests. What it means is I only trust claims that can be independently verified and do not require that I trust the judgement of people who may not be trustworthy.

    For example, the basics of radiative physics can be verified in a lab so I do not question that changing the concentration of CO2 from 0.03% to 0.05% will cause some warming. Unfortunately, no such verification is possible for climate sensitivity which means I put a lot more weight on the recent temperature trends which offer experimental evidence that CO2 sensitivity is lower than claimed.

    Last thing. A see anti-CO2 as hugely expensive and doomed to fail because the technology does not exist. For that reason the more responsible course of action in face of uncertainty is to wait and see. IOW, “Primum non nocere” trumps the “precautionary principal” for me.

  38. Bart Says:

    Dick Veldkamp,

    Your points 3-5 echo some of mine I think, and (naturally) I agree.

    Your fits point though strikes me as irrelevant: I dont see why someone’s writing style would say anything about the trustworthiness or truthness of their opinion. Actually, a lot of scientists are awefull communicators, and spin doctors on the ohter hand are veryy good communicators. I wouldn’t quite argue the opposite of your first claim either though. Greg Craven is great indeed.


    My list (at least without the examples) is just common sense I think. For other complex issues you could use very similar hints I think. See eg for health issues an example here.

    What’s alarmist (or its opposite, denialist) or not is very much in the eye of the beholder. Warning for global economic collapse if we reduce CO2 strikes me as patently alarmist for example.

    A wait and see approach in the face of a credible threat may have severe risks. In a heavy snowstorm you wouldn’t continue driving 120 km/h either. If you deem the risk low, you’d better be very sure of that. Just pointing at uncertainty doesn’t reduce the risk (to the contrary).

    The instrumental record doesn’t pose strong constraints on climate sensitivity, because the aerosol forcing is poorly knowns and because the deviation from equilibrium is poorly known. Better constraints are eg from the last ice age or volcanic eruptions, and such estimates converge at around 3 (+/- 1) deg per doubling of CO2. Which is consistent with the 20th century record.

  39. Raven Says:


    I see you missed by “Primum non nocere” reference. That is the latin for the warning given doctors called ‘first, do no harm’. i.e. doctors are told that given uncertainty about the course of a disease and the potential harmful effects of the treatment that it is often bettter to do nothing.

    When I go do a doctor I expect that my doctor has considered this dictim before giving me advice because it is part of the culture of medicine. Climate science has no such equivalent, in fact, there is a lot of evidence that climate scientists are completely oblivious to the harms that will be caused by their recommendations. For that reason it is quite rediculous to compare the advice of climate scientists to the advice of doctors.

    I also did not say that controlling CO2 would cause ‘global economic collapse’. I said it would be hugely expensive and ultimately futile because we do not have the technology to do much about CO2 within the timeframes demanded.

    Unfortunately, the same people who lecture sceptics about the laws of physics and CO2 seem to willing to ignore them when it comes to producing and distributing the energy that an advanced society needs to function. Many sceptics are sceptics simply because they feel that nothing can be done and the people advocating action are deluding themselves.

  40. Raven Says:


    1) I feel it is wrong to assume that CO2 sensitivity is a constant and there is no reason to believe that the sensitivity observed during the ice ages is the same as today. There are simply too many unknowns (i.e. the relationship between the biosphere and cloud formation).

    2) The uncertainties in the aerosols are why groupthink matters. In another universe a different group of scientists could use the same data come up with completely different ranges for CO2 sensitivity. The only thing special about 3degC is it is large enough to provide scary stories but not so large that people become fatalistic.

  41. Bart Says:


    How would your opinion on what can or cannot be done about the problem influence your diagnosis of the problem? It shouldn’t, right?

    It is probably a very human trait, but the physical climate doesn’t care about your opinion on e.g. renewable energy. I would respect the same opinion about emission reduction a lot more when the science wasn’t bended in the process.

    See also this post :
    Consider the analogy of a lifelong smoker who goes to see his doctor for breathing problems. The doctor may say: “All the indications point towards your lung function deteriorating. This is very likely related to you having smoked for X decades. In order to minimize the risk to your health, I urge you to quit smoking.”

    If you don’t want to quit smoking, fine (in the case of smoking at least), but that’s by itself no reason to attack or doubt the doctor’s diagnosis.

    Your ‘completely different’ in your next comment (re clim sensitivity) is a bit of a stretch. Your accusation that it is governed by offering up scary stories gets into the most unlikely kind of conspiracy theory (nr 3 in my list). I can’t take that seriously.

  42. Raven Says:


    You are medical analogies are completely in appropriate.

    A more appropriate one is a doctor telling a patient who shows no symptoms that lab experiments on rats suggest the patient might develop cancer in 80 years and to prevent that the patient needs to have both legs amputated immediately.

    The doctor could be right but it is irresponsible for the doctor to be recommending such a treatment given harms caused by the treatment.

    I was being a bit tongue in cheek with my claim about the providence of the 3degC number. My understanding is the true origin dates back to the 70s when Hansen has a model with 4degC sensitivity and Manabe has one with 2degC sensitivity. They agreed to split the difference and add 0.5 deg on either side (1.5-4.5). Since then all subsequent science has been judged by its ability to confirm that sensitivity was in that range.

    Frankly, I think it is wrong to dismiss the dangers of groupthink simply because its effects look similar to that of a consipiracy. Groupthink is real phenomea and the rhetoric used by climate scientists like the ones on RC make it very hard for anyone to argue that groupthink is not at work.

  43. Hank Roberts Says:

    Oh, Raven again with the massive conspiracy theory.

  44. Raven Says:


    You are projecting again. Don’t you have some lead on big oil/big coal donation to a think tank that is loosely connected to someone vaguely connect to Dr. Curry that shows she is has been bought and paid for? You can make it game of it like “6 degrees of bacon”.

  45. Hengist McStone Says:

    Apropos the original posting, I’d like to add it’s pretty clear that there’s a disconnect between what the scientists know and what the media are reporting to us further down the information food chain.

    The mainstream media’s coverage of global warming is something of a moveable feast. You can choose your reputable source, your evidence, to reflect your preconcieved views . Isn’t this what Scientists call “confirmation bias”? There is a wide range of theories in the mainstream media surrounding global warming and not all of them can be true. It’s fair to say therefore that taken as a whole the mainstream media’s approach is unscientific. IMHO

  46. MikeN Says:

    Tom is right when he talks about how people evaluate credibility.

    When a scientist (Mann et al 2007) uses data upside down, that makes the guy look incompetent, maybe he shouldn’t be believed. The same applies to McIntyre’s coauthor McKitrick who switched degrees and radians.

    Then we look at what happened when the mistake is pointed out. Skeptic McKitrick corrected the paper and admitted the error. Michael Mann said the accusation was bizarre, his algorithm is blind to upside-down usage. So it appears the skeptics are 0 for 2.

  47. Gavin Schmidt and Judith Curry on Science Advocacy by Dr. Bart Verheggen Says:

    […] broader political objectives that support any/all of the above: This goes more likely in the direction of downplaying rather than overplaying AGW I would argue. […]

  48. FORUM REPORT 01 Says:

    […] broader political objectives that support any/all of the above: This goes more likely in the direction of downplaying rather than overplaying AGW I would argue. […]

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