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Is the climate consensus 97%, 99.9%, or is plate tectonics a hoax?

Posted on 4 May 2017 by dana1981

Four years ago, my colleagues and I published a paper finding a 97% consensus in the peer-reviewed literature on human-caused global warming. Since then, it’s been the subject of constant myths, misinformation, and denial. In fact, last year we teamed up with the authors of six other consensus papers, showing that with a variety of different approaches, we all found the expert consensus on human-caused global warming is 90–100%.

Most of the critiques of our paper claim the consensus is somehow below 97%. For example, in a recent congressional hearing, Lamar Smith (R-TX) claimed we had gone wrong by only considering “a small sample of a small sample” of climate studies, and when estimated his preferred way, it’s less than 1%. But in a paper published last year, James Powell argued that the expert consensus actually higher – well over 99%.

We thus had three quite different estimates of the expert consensus on human-caused global warming: less than 1%, 97%, or 99.99%. So which is right?

Testing the 97% approach with plate tectonics

Yesterday, the Bulletin of Science, Technology & Society published our response to Powell, led by Andy Skuce. To determine who’s right, we turned our sights on the theory of plate tectonics.

In his critique of our study, Powell argued that on scientific theories as settled as human-caused global warming or plate tectonics, scientists don’t bother to state the obvious. In our 97% paper, we examined how many studies endorsed, rejected or minimized, or took no position on human-caused global warming.

In his study, Powell only looked at papers explicitly rejecting the human cause; he assumed that the rest endorsed the consensus. And, he argued, applying our approach to another settled scientific theory like plate tectonics wouldn’t yield any results, because Powell assumed no scientist would bother to state something so obvious. If our approach weren’t valid for plate tectonics, Powell argued that it wouldn’t be valid for global warming either.

So we tested our approach by looking at 331 papers from the journals Geology and the Journal of the Geological Society, checking whether they endorsed, rejected, or took no position on the theory of plate tectonics. Using our method, we found 29% of the papers’ abstracts included language that implicitly endorsed the theory of plate tectonics, while the rest took no position. In short, of the papers taking a position, we found 100% consensus on plate tectonics in our sample of the peer-reviewed literature. Our method worked.


Using Powell’s method of only looking for explicit rejections of the theory, the consensus on plate tectonics is also 100%. However, in our survey of the climate literature, we found 2–3% of papers that implicitly rejected or minimized human-caused global warming or were uncertain about the causes. By assuming that those papers that don’t explicitly reject the theory endorse it, Powell overestimated the climate consensus.

Using the 97% consensus denial approach, plate tectonics is a hoax

‘Minimized’ is a key word in the approach of our 97% consensus paper. A common myth, articulated by Lamar Smith and in the video below by Washington State Senator and newly appointed EPA bureaucrat Doug Ericksen, claims that studies that attribute any amount of global warming to human activities are included in the 97%.

In reality, if a paper said humans are responsible for less than half of global warming since 1950, we put it in the category of the less than 3% of papers rejecting or minimizing human-caused global warming.

The latest IPCC report, which summarizes our best current scientific understanding, said with over 95% confidence that humans are responsible for most of the global warming since 1950, and most likely responsible for all of it. While it’s not safe to assume that a paper that doesn’t explicitly reject this consensus must be endorsing it – as Powell did – it is safe to assume that a paper endorsing human-caused global warming also endorses the IPCC position unless it says otherwise.

Lamar Smith also referenced a common denier argument that consensus should be measured by comparing the number of papers explicitly endorsing the theory to the total number of papers examined. By that measure, 0 out of 331 geology papers endorsed the theory, meaning the consensus is 0% and clearly plate tectonics is a hoax.

Ultimately those are our three options in defining the climate “consensus.” Either every paper that doesn’t explicitly reject human-caused global warming is part of the 99.9% consensus, or 97% of papers taking a position on the cause of global warming are part of the consensus endorsing the theory, or climate science and plate tectonics are both hoaxes.

It’s most accurate to say that 97% of relevant peer-reviewed studies agree that humans are causing global warming, 99.9% of climate papers don’t reject that theory, and those who deny the overwhelming consensus are peddling misinformation.

Does it matter if the climate consensus is 97% or 99.9%?

The title of our paper asked, “Does it matter if the consensus on anthropogenic global warming is 97% or 99.99%?” Either way, the public dramatically underestimates the level of expert consensus. 

Click here to read the rest

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Comments 1 to 11:

  1. What you say makes complete sense to me. Lamar Smith means well, but his methodolgy doesn't make sense. The Cooke study methodology makes more sense to me.

    You also have to apply the commonsense test to any methodology. You would expect a few more sceptics in climate change than geology given issues such as vested interests, politics, and ideology that are not remotely as dominant in plate techtonics. So 90 - 97% sounds right to me and 99.7% would seem unlikely. More importantly this means 90-97% is a powerful number, in the circumstances.

    The real issue is more related to the media. They don't report so much on the consensus studies, and perhaps this is becasuse they prefer to keep a rather false or exaggerated debate going. This, if its true, is outrageous as it's putting the safety of the entire planet at risk.

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  2. When was the last article skeptical of plate tectonics published?

    I remember vaguely someone in the Soviet Union doing that some decades ago.

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  3. I think you need to be more specific. By "published", I assume you mean published in peer review journal. Plate tectonics is a vast theory with many aspects to it and some have been considerably more controversial than other. (The current theory of climate is similar). Criticizing some critical aspect of plate tectonics would be a while a ago, but in detail there is a lot of work to do.

    Skepiticism about AGW can take many forms.

    - skepticism about the GHE would be like skepticism of mobile plates and it would indeed be a long time since a paper like that showed up in proper peer review.

    - that man is responsible for CO2 increase is just about in same category but there is indeed a recent publication ( a serious failure of peer review) doing just that. I doubt you can find an actual climate scientist who doubts it however.

    - the GHG is primarily responsible for current climate change and that climate sensitivity is significant are much more focus of published peer reviewed science papers. Got one that hasnt been shot down?? This is the camp of any vaguely respectable scientist with any expertise on climate (Lindzen, Curry, Peikle, Spenser, Christie, Tsonis, who else??).

    The one big difference between plate tectonics and climate science is that plate tectonics does not imply a policy response and furthermore not a response that is antipathetic to entrenched ideology and vested interests. Got a "skeptical" scientist that does have motivated denial?

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  4. And in answer to question, at first look James Maxlow still seems to carry the baton of alternative theory from carrey et al. Last publication I can see in 2001 though did a book in 2005.

    Oh, yes Jan Koziar, a pole maybe. Published this in 2016.

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  5. There were a couple of fairly recent articles cited in the paper that would count as rejection of plate tectonics:

    Ollier, C. D. (2006). A plate tectonics failure: the geological cycle and conservation of continents and oceans. Lavecchia, G. and G. Scalera (eds.), 427-436.

    Scalera, G. (2003). The expanding Earth: a sound idea for the new millennium. Why expanding Earth? A book in honour of OC Hilgenberg. INGV, Rome, 181-232.

    These are published in books and it's doubtful if they were rigorously peer reviewed. There are probably others. Incidentally, I believe Ollier also rejects the mainstream position on climate change.

    The last prominent western scientist to reject plate tectonics was the American petroleum geologist Art Meyerhoff.

    The Soviets were slow to embrace plate tectonics, mainly because of the influence of the influential old men who ran major research institutions. The Communist Party actually accepted the theory before many of the Soviet Union's scientists did. 

    My first ever geology course at Sheffield University in 1972 was taught by the department head, who was a plate tectonics denier.

    There's more on this in my blog article Consensus on plate tectonics and climate science.

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  6. Consensus has little to do with science.  It may increase the probablility that the theory is correct a little but there are too many examples of consensus being wrong for us to harp on this point.  Climate change has the weight of peer reviewed science behind it and this is the point we should be emphasizing.  Plus the phenomenon of exposure.  A mountain climber would identify with this.  You may be on a very difficult climb on a bolder but are only a meter or two above the ground.  Nearly zero exposure.  On the other hand you may be on a cake walk on a ridge with 2000m below you on both sides.  Easy walk but horrendous exposure.  Climate change is like this.  The consequensus are ghastly if we are correct.  Besides, there are so many reasons other than climate change to get off fossil fuels.  Perhaps we should hammer this with the unbelievers.

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  7. Why is it that when the completely ignorant with no relevant knowledge on a topic want to demonstrate to the world how foolish they are, they cannot post on just one thread?  Like monkeys flinging shit, they don't seem happy unless they've smeared every wall.

    In any event, refutation here

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    Moderator Response:

    [PS] Thanks Tom. Normally replies to deleted get dumped too but given your effort, it should stand and perhaps it might give our visitor some indication on the knowledge gap (not hopeful however).

    Dean - 

    Please note that posting comments here at SkS is a privilege, not a right.  This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.

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    I suspect that Sks is not the site for you - other forums (eg WUWT) welcome comments likes yours.

  8. Are not facts reached by consensus?

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  9. What determines an atmospheric gas' potential heat capacity?* Anyone know? Anyone take high school physical science or physics? What physical feature of a gas determines what the gas is capable of ingesting regarding heat? Don't remember? Does VOLUME ring a bell? Ahhh...volume! Yes, volume. So let's take a look at the volumes of carbon dioxide, oxygen and nitrogen ...

    One pound of Carbon Dioxide has a volume of 8.7 cubic feet,

    Oxygen is at 12.1 cubic feet.

    Nitrogen is at 13.8 cubic feet

    With a smaller volume than either Nitrogen and Oxygen,
    Carbon Dioxide can only possess LESS heat than Nitrogen and Oxygen, and when more COOLER carbon dioxide is pumped into the Nitrogen-Oxygen based atmosphere (>99% of the atmosphere's gasses), the result can only be a COOLING of the atmosphere.

    When the volume of any planet's atmosphere is increased by additions of a cooler trace gas such as Carbon Dioxide is on Earth, the result can only be a cooling of the planet, all other variables remaining constant. And if other variables should increase the heat of a planet, such as increased radiation from the planet's star(s), then the additional trace gas will have a RELATIVE cooling effect on the planet. To better grasp this fact, let's use a more familiar everyday experience we witness involving water: When a small amount of cooler water is added to a larger warmer body of water, the result is a cooling of the water.

    So what is warming the planet, you ask? The heat obtained by both Nitrogen and Oxygen comes from thermals and latent heat from the surface, heat from man-made structures on the ground, and the heat produced by incoming radiation absorbed directly by the atmosphere, not solely from the absorption of outgoing IR. The warmth that blankets us each day is due to Nitrogen and Oxygen, not the puny amounts of the trace gas Carbon Dioxide, nor any of the other trace gasses.

    Regarding man-made structures on the ground, interestingly NASA's 'earth's energy budget' illustration fails to provide the data on the amount of solar radiation absorbed by those structures, and it is the massive growth of urban sprawl the last sixty years that accounts for the atmosphere's warming, a warming that is being tempered by increasing amounts of Carbon Dioxide in the atmosphere.

    That being cleared up, do you recall your high school chemistry teacher’s instruction on the high heating effect of Carbon Dioxide, where there's two jars and a heater next to each of the two jars? Carbon Dioxide is pumped into the second jar, and the temperature rises faster than the temperature in the first jar, thereby proving that Carbon Dioxide is a warming molecule. What the teacher didn't tell you is that by adding more Carbon Dioxide into the second jar, naturally the temperature within the jar will rise faster than the first jar because the atmospheric pressure in the second jar is GREATER due to the addition of the extra Carbon Dioxide!

    For those scratching their heads, forgetting their high school physical science class instruction, increasing atmospheric pressure increases heat.

    Now, a proper experiment, using the scientific method, would have included a third and fourth jar, where additional Nitrogen is pumped into the third jar, and additional Oxygen pumped into the fourth jar. But the scientific method isn’t used, because if it were the temperatures within the third and fourth jars would climb even higher than the second jar where additional amounts of Carbon Dioxide are pumped in.'


    * No, not 'molar heat capacity' as Tom Curtis informed us on another thread, since molar heat capacity tells us nothing about a gas' heat capacity due to their EXPANDING WITH HEAT! Molar heat capacity measures the heat capacity of the particles that are in a gas, and since gasses expand due to heat, molar heat capacity can't be used to solely quantify the heat of a gas. Molar heat capacity contributes to a gas' potential heat in also expanding the gas, therefore one must add molar heat capacity AND specific heat capacity (volume) to obtain the correct temperature of a gas.

    When Nitrogen, Oxygen, and Carbon Dioxide are at 70 F (and 1 atmosphere), all three have the same temperature, but which molecule has approximately one-third less of the 70 F temperature? Carbon Dioxide, which proves it's a cooling molecule in Earth's atmosphere.


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  10. william...

    This meme--popular among the disinformed, misinformed, and naive--is ridiculous. Without consensus, it is very dificult to do science at all.

    Galileo is remembered as right because he contributed greatly to the consensus of those qualified to judge his work. 

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  11. In the case of "plate tectonics denial", if the theory of plate tectonics had said that fossil fuel extraction would cause an unheralded increase in the rate of plate movements, and this would lead to huge increases in earthquake activity and great damages to many populated areas close to fault zones (hi, California!), with huge impacts on society as me know it, would this have led to corporate funding of plate-tectonic-denial think tanks? Would companies like Exxon have invested large amounts of money to deny the science in order to protect their business, as they have with anthropogenic climate change?

    Fortunately, plate tectonic theory made no such predictions, so corporate interests did not react that way, but how has the fossil fuel industry reacted to claims that fracking causes earthquakes?

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