The Fallacy of the Ninety-Seven Percent

By Ruth Weiner

The history of science is replete with stories of a skeptic overturning a long-held belief: Galileo, Kepler, Newton, Rutherford, Einstein. Acceptance of the new evidence and phenomenon becomes the consensus. However, in historic instances of substitution of a new consensus for an old one, the new consensus would be supported by independent observation and analysis of some sort.  Moreover, the new consensus is often merely a refinement of the old consensus: e.g., quantum mechanics is the Heisenberg refinement of Newtonian mechanics.

In fact, a scientific agreement exists only as long as observations confirm it. Then a non-conforming observation becomes the basis of a new consensus.

Treatment of stomach ulcers is another interesting example. Stomach ulcers were thought to be caused by stress and diet, and treated accordingly and with mixed success, until discovery of the helicobacter. Stomach ulcers are now treated successfully as bacterial infections. I experienced this in my own doctoral research: the gamma-induced chemical bond breakage I observed and analyzed was completely different from the analogous phenomenon recorded and published by the leading expert in this particular field.

Scientific thought progresses as a result of skepticism about a consensus rather than by invocation of that consensus. The fallacy of the 97 percent is not that it was the wrong number or that the subject group was improperly identified, but that the phenomenon – that atmospheric carbon dioxide drives global climate change and global warming — has not been demonstrated in the physical world, nor is it currently demonstrated; perhaps it cannot be demonstrated definitively. The skepticism about this agreement, though widely ridiculed, has not been examined. The history of scientific unanimity suggests that skepticism cannot be dismissed summarily. The only phenomenon about which there can be a consensus of climate change experts, no matter how many agree, is that the earth’s climate changes continually and human activity has some unquantified influence on such changes.

The 97 percent agreement does not support the climate change role of carbon dioxide at all. There are other, considerably more substantive reasons to question the primacy of carbon dioxide’s role in global climate change.

Dr. Ruth WeinerDr. Ruth Weiner is currently a senior consultant at AECOM and adjunct professor of nuclear engineering at the University of Michigan. Together with Brian Grimes, she initiated the ANS Seaborg Congressional Fellowship program. She is a Fellow of ANS.  Dr. Weiner is the author and co-author of several books and papers. She was awarded the 2017 Lifetime Achievement Award by the Fuel Cycle and Waste Management Division of ANS.


12 thoughts on “The Fallacy of the Ninety-Seven Percent

  1. Anonymous

    The 97% support of “climate change reality came from a poll of 100 atmospheric scientists .But the list of 100 came from scientists with gov’t research support contacts from EPA and other gov’t agencies. The curious thing might come from the 3 who dared to disagree. The real issue is the actual effect of CO2.
    (info from SEPP.)
    The activist and gov’t actions based on the CO2 conclusion have done the most harm.
    – – Dave Rossin.

  2. Sam Ross

    Ruth Weiner’s insight into the problem with the 97% statement deserves wide publication. Who will be the Galileo or Newton skeptic of climate change? Will the real credible scientist on climate change please step forward and explain the shortcomings in the arguments that are being used to support expenditures of billions of dollars to stop Mother Nature from doing what she will do anyway?

    What does it take to be counted among the 3%? Nobody has ever ask me for my opinion, but I would vote to be a 3% skeptic if ask. But then I am just an engineer who was responsible for coordinating meteorological studies for siting a nuclear power plant and have read quite a bit on the subject by authors such as Singer and Avery. Does that qualify for me to offer an opinion? Were most of the 97% who are given credit for selling the Kyoto Protocol any better qualified? And even so, as Ruth Weiner has pointed out, did they have any real scientific evidence to back them up? Sorry, but computer models don’t qualify as real scientific evidence.

  3. John Tanner

    True, prior to 3 million years ago, the earth was consistently warmer than now. We are now at least several tenths of a degree (C) warmer than at any time since then. Particularly noteworthy is the accelerating rate of temperature rise in the last 100 years. It coincides neatly with the rise of the industrial age and the increasing burning of coal and oil. The 97% quoted above simply represents the conclusions of most scientists based on these facts, reinforced on theoretical grounds by the known absorption spectrum of carbon dioxide.

  4. Brian Mays

    Jim Fancher wrote:

    2) why laboratory work confirming the thermal reflective characteristics of atmospheric carbon dioxide should not be considered supportive …

    It’s not about that. A relatively simple calculation shows that the absorption characteristics of carbon dioxide result in an increase of slightly above 1 degree Celsius when the concentration of carbon dioxide in the atmosphere is doubled. Very few people disagree about this.

    That is, if we assume that carbon dioxide concentrations in the atmosphere have increased by 43% over their preindustrial levels, then this effect would increase global temperatures by 0.6 degrees Celsius. This is not much to worry about. To reach the “devastating” 2-degree-Celsius temperature increase that has been selected by various intergovernmental agreements and the popular press as the “end of the world as we know it,” we would need to increase the concentration of carbon dioxide by a factor of 3.5.

    To put this in perspective, all of the carbon dioxide that has been dumped into the atmosphere since the beginning of the industrial revolution has raised the concentration by 120 ppm. To reach the “doomsday” scenario, we would need to take the concentration up to almost 1000 ppm, or eight times what we have already done over two centuries.

    So the phenomenological trivia that carbon dioxide adsorbs infrared light is not enough to raise a call to action. The alarmist claims require various feedbacks in the complex dynamical system that is Earth’s atmosphere, which the advocates must assume is strongly positive in order to draw their alarmist conclusions. This is the purpose of the GCM’s (climate models) — they try to estimate (or fudge, depending on how you look at it) how strong this effect is.

    So the debate is not about the basic science of atmospheric chemistry and photon absorption. It is really about the magnitude and direction of the various feedback mechanisms (some of which are very poorly understood, even today, such as cloud effects) that determine the ultimate effect of carbon dioxide concentration in the atmosphere.

  5. Gene Preston

    In the observation that CO2 rise seems to follow increased temperatures I’ve begun to wonder if CO2 tracks warming. If you look at the geological methane rise and temperature rise you see that they track closely followed by a CO2 rise. The methane goes away after a while and the high temperatures remain as long as the CO2 remains high. This suggests that some geological events may have released a lot of methane in the past, such as the methane ices in the ocean, causing a warming, and then that warming releasing more CO2 from oceans and other sources. So in the past possibly methane triggered some events and CO2 followed
    Today we possibly have the reverse, CO2 rise will trigger methane release. If this is the case we will have a heat wave spike we have not yet observed as methane is released around the world from warming oceans and thawing tundra. We can sit back and watch the show because at this point there is no likely way we can stop this trigger event of methane release.
    I did see a presentation on methane release at the University of Texas about ten years ago and the speaker thought that the ocean rise would occur first putting the methane under pressure and holding it there. It remains to be seen which will occur first, ocean rise or methane release.

  6. Andy

    This article is flabbergasting to me in this specific forum…
    without getting into the discussion of consensus or data and indications etc, we are a nuclear society-organization. The main driver or motivation for younger people into the field is a perceived ability to tackle the climate change issue (regardless of it’s potential validity), secondly, as a driver for promoting nuclear it is unrivaled. I dare others to come up with good reasons for why to use nuclear to push out other power genrating capabilities.
    For an uindustry in decline, aging, and reduced impact we should jump at any opportunity to revitalize, rejuvenize, and promote the use, building and expansio nof nuclear engineering and power. I can’t see any other than the opposite effect of that of this type of discussion. I don’t mind seeing the discussion for general education etc, but why is it in this forum instead of being used as what might be the last great potential driver for advancing nuclear power (“emission free”, “low climate impact” or which-ever suitable promoting phrase we want to take advantage of?).
    Beyond the destructive impact on nuclear that this is having I also have some issues with this “unhealthy skepticism”.
    Take the first comment and the linked article, the linked article is using a couple of cherry-picked graph-breaks to show slow larger swings as some type of counter indicator? the proper scaled graph is what shows the alarm: If a cartoon can be significant;y more representative of graphing data then one really ought to be careful of using that as a “counter-science” argument. The leak on cherry-picked data from climate scientists can’t be countered with even better cherry-picking and graph-/data manipulation. All credibility is then lost when criticizing the same point.
    This articles point tha:
    “that atmospheric carbon dioxide drives global climate change and global warming — has not been demonstrated in the physical world”.
    Is seemingly a very odd statement, even very old models predict and have it measured almost identically to the degree and change that is indicated from basic atmospheric studies:
    Can there be dips or deviations as in shown in “5 thoughts link”? certainly, especially if selecting a baseline of a few how years so the first dip in the nineties first back to trend mean and then below it looks like a “failed model”.
    I would challenge nuclear engineers to find other scientific findings or trends that can be used as major drivers for nuclear industry and nuclear adoption. If you can’t then this discussion just further helps shooting ourselves in the foot. Instead of opening up a great new positive opportunity that I would be wishing nuclear would be seen as a viable safe, solid solution.

    The discussion of the cost would be too high to try and combat emissions, that argument is main argument against the large capital cost of nuclear, which is one of the main hurdles that our stagnant industry/field is suffering from.

    For the sake of nuclear and having an industry that does not alienate positive change and recruitment and rejuvenation of our cause I would posit that those pushing this “healthy skepticism” in our field are likely to cause it’s final demise instead of it’s promotion.
    As a person likely to see the larger negative impacts in my lifetime, I find the argument:
    “So the most important question may well be:
    How can we best adapt to expected climate change scenarios?”
    To be so ludicris, since it is using the same data/models it tries to debunk for this purpose: “seeking realistic strategies to adapt to the most probable climate change scenarios” instead of attempting to stop them. And now those impacts should be taken form the models one promotes skepticism about? That discussion promotes nothing in nuclear other than possibly shutting some plants down due to heat-sink impacts if using rivers/oceans pending the NPP location.
    And “outsized costs” falls pretty flat on it’s face when looking at countries with non/little fossil power component like France or Sweden, and in addition those countries have a vastly higher nuclear component than US, so lets aim for that!
    This is a discussion you won’t find of this odd amplitude in other countries/continents (it certainty exists, I won’t deny that, but the discussion regarding a flat earth and the health benefits form smoking also exists, that existence alone does not lend any credence…). Time to seize nuclear opportunities rather than helping the demise of the field…

  7. Sherrell Greene

    Great post! Robust debate is always useful. I’m old school. A hypothesis that is so constructed that even if it is incorrect it cannot be refuted (negated) by measurement, isn’t science. It’s dogma or religion. Doesn’t mean it isn’t true. Just means it isn’t science. I’ve grown increasingly concerned over the past couple of decades about the incremental abandonment of the Scientific Method by some in the “scientific community” as computing has become more affordable while experiments and data collection have become more expensive. Computational models are powerful tools of modern science. But, computational models – particularly when their predictions are not DIRECTLY comparable to DIRECTLY measurable parameters – can, have, and will continue from time to time to lead us astray. We never know what we don’t know. And we never know everything. Show me the data! My take on the climate debate is here:

  8. E. Calvin Beisner

    Excellent article. Veteran climate scientist Dr. Neil L. Frank (who was the longest-running Director of the National Hurricane Center) did a thorough critique in his article “What’s Wrong with the Claim that “97% of Climate Scientists Agree” about Global Warming?” ( He showed specific major weaknesses in the most widely cited studies that embraced the figure. The issue isn’t just that consensus isn’t really a scientific (rather a political) value. It’s that the methodologies that yield the number are wrong. It’s time to stop talking consensus and start talking science–particularly the strong empirical evidence that the climate models that simulate large-scale, rapid warming from rising atmospheric CO2 concentration predict two to three times the warming actually observed over the relevant period.

  9. Jim Fancher

    Ruth is certainly correct to raise this point. But, if there is another explanation, it has to explain 1) why CO2 concentrations track average termperature rise so well (driven by the same mechanism, perhaps?), and 2) why laboratory work confirming the thermal reflective characteristics of atmospheric CO2 should not be considered supportive …
    In “Sources, Abundance, and Fate of Gaseous Atmospheric Pollutants”, a monograph released in 1968 (commissioned, by the way, by API !), Elmer Robinson and his colleague ______ Robbins– then, I believe, at Stanford– highlighted the CO2 trend, based on measurements in Hawaii, and expressed concern; CO2 was not, at that time, considered a pollutant, and they had added it to their report simply for completeness. The CO2 connection with climate was investigated by others, although the suggestion that CO2 might influence climate had, I believe, earlier roots.
    Of course I am NOT a climate scientist, and I can only read and listen to what people in that field are telling us. And, yes, I do recognize that holes have been poked in other theories by outsiders. But we do not always need to prove Velikovskys wrong… The ozone “hole” connection with anthropogenic chemicals was postulated upon less support than the current CO2 issue, and we are now seeing evidence that the action taken in that case has been effective. Unfortunately, if the CO2/climate connection is correct, it would take a long time from the institution of effective controls before we could get that kind of confirmation.

  10. Ed Picazo

    Finally, a voice of wise observation amid the swirling miasma of political posturing – not unlike the Copernicus/Galileo situation. Although I am a skeptic on many fronts, I have been trained to “believe my instrument indications,” but this comes only with understanding the extent, and limitations, of the parameter measurement. To honestly approach the climate change issue in the Gestalt, us humans may find in the end that although we may have mega-line climate models, we are missing big chunks of important information which might eventually lead us back to the conclusion popularized 40 years ago – buy firewood to avoid freezing to death in the coming ice age! One thing is obvious, and gives me hope for the future: the subject is finally being analyzed and discussed by true scientists who actually will not take just any consensus answer for the truth, but have the Missouri “show me” attitude. Here’s to the true scientific method! And a warm fireplace…

  11. Hank Phillips

    A little algebra goes a long way in this 97% documendacity. My professors circulated the Petition Project, and to sign you had to have at least a Bachelor of Science. Way over 31000 signatures were recorded and verifed; those signers are listed online to this day. Supposing these anti-Kyoto protocolists to be ALL the non-Millerites, for them to be the 3% would require that five times the combined memberships of the American Chemical and Physical societies be Misanthropomorphic Climate Cassandras. Fermi would ask: “Where are they?”

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