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The 97% consensus on global warming

What the science says...

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97% of climate experts agree humans are causing global warming.

Climate Myth...

There is no consensus

The Petition Project features over 31,000 scientists signing the petition stating "There is no convincing scientific evidence that human release of carbon dioxide will, in the forseeable future, cause catastrophic heating of the Earth's atmosphere ...". (Petition Project)

Science achieves a consensus when scientists stop arguing.  When a question is first asked – like ‘what would happen if we put a load more CO2 in the atmosphere?’ – there may be many hypotheses about cause and effect. Over a period of time, each idea is tested and retested – the processes of the scientific method – because all scientists know that reputation and kudos go to those who find the right answer (and everyone else becomes an irrelevant footnote in the history of science).  Nearly all hypotheses will fall by the wayside during this testing period, because only one is going to answer the question properly, without leaving all kinds of odd dangling bits that don’t quite add up. Bad theories are usually rather untidy.

But the testing period must come to an end. Gradually, the focus of investigation narrows down to those avenues that continue to make sense, that still add up, and quite often a good theory will reveal additional answers, or make powerful predictions, that add substance to the theory.

So a consensus in science is different from a political one. There is no vote. Scientists just give up arguing because the sheer weight of consistent evidence is too compelling, the tide too strong to swim against any longer. Scientists change their minds on the basis of the evidence, and a consensus emerges over time. Not only do scientists stop arguing, they also start relying on each other's work. All science depends on that which precedes it, and when one scientist builds on the work of another, he acknowledges the work of others through citations. The work that forms the foundation of climate change science is cited with great frequency by many other scientists, demonstrating that the theory is widely accepted - and relied upon.

In the scientific field of climate studies – which is informed by many different disciplines – the consensus is demonstrated by the number of scientists who have stopped arguing about what is causing climate change – and that’s nearly all of them.

Authors of seven climate consensus studies — including Naomi OreskesPeter DoranWilliam AndereggBart VerheggenEd MaibachJ. Stuart Carlton, and John Cook — co-authored a paper that should settle this question once and for all. The two key conclusions from the paper are:

1) Depending on exactly how you measure the expert consensus, it’s somewhere between 90% and 100% that agree humans are responsible for climate change, with most of our studies finding 97% consensus among publishing climate scientists.

2) The greater the climate expertise among those surveyed, the higher the consensus on human-caused global warming.

consensus studies

Expert consensus results on the question of human-caused global warming among the previous studies published by the co-authors of Cook et al. (2016). Illustration: John Cook.  Available on the SkS Graphics page

consensus vs expertise

Scientific consensus on human-caused global warming as compared to the expertise of the surveyed sample. There’s a strong correlation between consensus and climate science expertise. Illustration: John Cook. Available on the SkS Graphics page

Expert consensus is a powerful thing. People know we don’t have the time or capacity to learn about everything, and so we frequently defer to the conclusions of experts. It’s why we visit doctors when we’re ill. The same is true of climate change: most people defer to the expert consensus of climate scientists. Crucially, as we note in our paper:

Public perception of the scientific consensus has been found to be a gateway belief, affecting other climate beliefs and attitudes including policy support.

That’s why those who oppose taking action to curb climate change have engaged in a misinformation campaign to deny the existence of the expert consensus. They’ve been largely successful, as the public badly underestimate the expert consensus, in what we call the “consensus gap.” Only 16% of Americans realize that the consensus is above 90%.

Lead author John Cook explaining the team’s 2016 consensus paper.


Last updated on 8 May 2016 by BaerbelW. View Archives

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Further reading

Richard Black at the BBC investigates whether there is a bias against skepticism in the scientific community.

More on what we're talking about when we say "scientific consensus,"  in an essay founded on Denial101x and scientific literature: Scientific Consensus isn’t a “Part” of the Scientific Method: it’s a Consequence of it. (or via

Further viewing

The "Climate Denial Crock of the Week" video series examines the list of "32,000 leading skeptical scientists."

Naomi Oreskes gives a thorough presentation of the development of our scientific understanding of anthropogenic global warming:

Here is a video summary of the various studies quantifying the scientific consensus on human-caused global warming, as well as the misinformation campaigns casting doubt on the consensus.


Many thanks to Joe Crouch for his efforts in tracking down scientific organizations endorsing the consensus as well as links to their public statements.


On 21 Jan 2012, we revised 'the skeptic argument' with a minor quote formatting correction.


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Comments 876 to 900 out of 908:

  1. One Planet Only Forever @ 875

    Trust me I do discuss human population with deniers.  Human activity and consumption has a huge impact on global warming.

  2. To add to KR @ 870

    PatrickSS kept propping Judith Curry up as some sort of climate expert who is being hushed from publsihing papers.  I also suggest PatrickSS that you look up her credentials.

    It always cracks me up as Judith is always the wild card deniers pull out of their back pockets and try to prop her us as some sort of credible climate science researcher such as Katharine Hayhoe.

    Here are a few links about who Judith is as well as her agenda.

    Judith Curry Was For Me Before She Was Against Me


    Climate Misinformation by Source: Judith Curry

    IPCC attribution statements redux: A response to Judith Curry

    Judith Curry - SourceWatch

  3. Hmmph.  If Dr Curry were an actor, then you would see her in B-grade movies, at best.

    Dr Lindzen would be the equivalent of Marlon Brando in his last few years ~ someone who once received some respect from those in the industry . . . but was now "washed up" and coasting along on the remnants of his past reputation.  Sic transit.

    Dr Happer . . . also the Emeritus Syndrome, plus something a bit uglier.

    Let's move on from the Ad Hom sketches, and look at the actual arguments that Curry puts forward as a "contrarian".  

    Her arguments ~ well, she doesn't have any really.   She has asserted that for late 20th Century warming, "up to about 60%" of it might (possibly) be caused by a concurrence of several long-cycle periodic ocean current phases (multi-decadal Atlantic overturning current plus other much longer century/multi-century cycles . . . cycles which most scientists consider to be no more than a twinkle in the eye of their "discoverers").  In other words, a load of balderdash.  But a straw which the desperate denialists like to grasp at.

    All the while, Curry wears heavily-shaded glasses which are pachyderm-polarised to show very little of the Elephant in the Room i.e. CO2 .

    Yes, Curry does admit that CO2 has a mild effect on global warming, but maintains that after  you subtract the surface warming effect of those concurrent ocean cycles, the remaining minor warming shows that CO2 is a minimal problem because it must be that the planet's ECS (climate sensitivity) is quite low.

    That's about the size of it.  The rest of her rhetoric is simply empty rhetoric ~ confusing & vague distractions from the underlying reality.  Just what certain American senators/Congressmen wish to hear.  So they call her up to speak to "committees" and thus provide themselves with a veneer of excuse to take no action on AGW.

    Essentially Curry is a misinformer, through the use of vagueness and innuendo.  Like an expensive barrister arguing for a guilty-as-sin client, she usually does not step over the line of absolute mendacity.  Not quite.

  4. Seems to me that any reasonably intelligent person can see that human activity MUST change the climate, a Cow fartingbin a barn changes the climate, it adds methane where there was none.  Lighting a match changes the climate, it burns O2 and adds heat where there was none. 

    The climate MUST change, the planet temperature MUST increase, this seems obvious to me, is it not to all? Now what is causing these changes is debatable.

    Is it reasonable to believe that the climate stays stagnant with 7 billion people living in this industrial environment?

    Is it reasonable to believe that these same 7 billion people adding quadrillions of btu’s of heat every year to the environment would not raise the local temperature?

    NASA graph from 1975 to 2018 is interesting and quite telling but it omits the math showingvhow much heat the increase of 120ppm of CO2 adds to the atmosphere.

    Has anyone here been able to complete this math?


    [PS] For "quadrillions of btus of heat", please see here for the maths and comment on that thread if you have questions.

    And frankly, of course scientists have done the maths. What do you think they do??

  5. "NASA graph from 1975 to 2018 is interesting and quite telling but it omits the math showingvhow much heat the increase of 120ppm of CO2 adds to the atmosphere.

    Has anyone here been able to complete this math?"

    roseland67, scientists have quantified the warming caused by human activities since preindustrial times and compared that to natural temperature forcings.

    Changes in the sun's output falling on the Earth from 1750-2011 are about 0.05 Watts/meter squared.

    By comparison, human activities from 1750-2011 warm the Earth by about 2.83 Watts/meter squared (AR5, WG1, Chapter 8, section 8.3.2, p. 676).

    What this means is that the warming driven by the GHGs coming from the human burning of fossil fuels since 1750 is over 50 times greater than the slight extra warming coming from the Sun itself over that same time interval.

    Radiative Forcing

  6. Rosland66 @879,

    For completeness the calculation which is yet to be set out here (although the moderation Response @879 links to the on-topic thread); according to the latest BP Statistical Review of World Energy it was 550 quadrillion BTUs added to the environment by "these same 7 billion people" in 2018, a value which equates to +0.036 Watts/meter squared in climatology-speak.

  7. I see the Heartland Institute has a new format for its misinformation campaign - At-A-Glance Summaries which back up a few bullet points with a page or two of paragraph-long summaries. High on the list of these lie-cards is one entitled "Consensus".

    This "Consensus" lie-card mainly cites (or more correctly misrepresents)  a 2016 survey of American Meteorological Society members.

    The first bold-as-brass assertion runs:-

    "A majority of scientists (including skeptics) believe the Earth is warming and humans are playing a role, but a strong majority of scientists are not very worried about it."

    There is no indication of the evidence they have to support this "strong majority."  Heartland's initial mention of this survey does rattle on about how many responding AMS members said they were "worried" by AGW and to what extent. Yet the survey never mentions the word "worried" once (or anything like it). Perhaps the proper take-away from the AMS survey is the finding from the responses that only "about one in twenty (3 to 5%) don’t think there will be any harm from climate change in the next 50 years." (Note that when the AMS members were also asked in the survey if they considered themselves "expert in climate science" only 37% were able to answer 'yes'.)

    Heartland also say of this same survey:-

    "Fully 40% of AMS members believe climate change impacts have been primarily beneficial or equally mixed between beneficial and harmful. Only 50% expect the impacts to be entirely or primarily harmful over the next 50 years. That is nowhere near a consensus." [My bold]

    The sole basis for this statement made by Heartland actually concerns not 'global' AGW but 'local' AGW -  "the impact(s) of local climate change in your area." It is also a mash-up of two seperate questions, one concerning "the past 50 years" and one "the next 50 years."  And each question is only asked of those who responded 'yes' to two preceding questions of the form "To the best of your knowledge, has/will the local climate in your area change over the past/next 50 years?" with  'yes' response of 74% for the past and 78% for the future. These 74%/78% then answered as follows:-

    The impacts will be exclusively beneficial - past 0%, next 0%

    The impacts will be primarily beneficial - past 4%, next 2%

    The impacts will be approximately equally mixed between beneficial and harmful - past 36%, next 29%

    The impacts will be primarily harmful - past 36%, next 47%

    The impacts will be exclusively harmful - past 2%, next 3%

    Don't know - past 21%, next 19%

    So the lie-card's "fully 40%" concerns the past 50 year's local climate change and is only the view of ([4%+36%] x 74% =) 29.6%. The word "fully" is a straight lie.

    A final assertion runs as follows:-
    "Scientists with NASA, NOAA, MIT, Harvard, Columbia, Princeton, and Penn, along with scientists who have served as official state climatologist for their states, are climate realists making the case against an impending climate crisis. These include many of the science giants of the past half-century, including Freeman Dyson, S. Fred Singer, and Will Happer."
    So with the exception of a trio of very ancient scientists (one of whom died the month before these At-A-Glance cards were launched), these AGW consensus-busting scientists who are "making the case against an impending climate crisis" appear to be all nameless phantoms of Heartland's imagination.
  8. Thanks, MA Rodger @882 ,

    the Heartland "Climate at a glance"  summaries have also recently been touted on WUWT  website:  I gather Mr Anthony Watts has had some co-writing input for the Summaries.   Unsurprisingly, they are a waste of time for anyone who wishes to learn anything truthful about climate matters.

    I have read a number of the Summaries (they are quite short).  Their pattern soon becomes evident :-  cherry-picking & strawman arguments, and the general tenor is that of advocate-lawyers rather than scientists.

    As you say, the "Consensus" summary did nothing but pick out and misrepresent one single study of members of the American Meteorological Organisation, and did not mention the World Meteorological Organisation . . . or any other organisations of greater relevance.   No nuance; no general context; no honesty of presentation.

    The "Summaries" are a complete waste of time for any inquiring mind ~ their only virtue is that they are brief.  Yet brief as they are, they have a surprising number of typos and spelling errors ~ this is surprising for such brief presentations from a supposedly-slick propaganda "Institute" like Heartland, where one would at least expect some proof-reading of stuff going onto permanent display.   Perhaps there is some truth in the rumors that Heartland has been forced to retrench staff.

  9. Eclectic @883,

    The purveyors of fakery at Heartland do seem to be re-branding themselves. As well as the recent appearance of their "Climate at a glance" website, a similar-looking site has reared its head with the title "ClimateREALISM" and proclaiming its mission saying:-

    "The climate alarmism industry and its media allies present a daily barrage of false, misleading, and one-sided information designed to convince people that a climate crisis is at hand. Climate Realism provides daily rebuttals to the alarmists’ Climate Delusion, giving the media and interested persons access to the facts, data, and perspectives that the put the daily media scares in proper perspective. Articles and information presented on this website can be accessed by date or by climate-related topic."

    This site too is provided with a "Consensus" page but the content doesn't even attempt to start to address the subject. I'd assume the rest of the site is likewise fake-heavy anf fact-light.

  10. Thanks MA Rodger and Electric! I can only predict that the climate deniers that I tango with will start parroting Heartlands misinformation campaign...especially the WUWT fans here in ‘Merica.

  11. TVC15 , if you have time for a 20-minute youtube video, then you might enjoy Potholer54 : "How to argue for science (and have fun!)" .

    Potholer54 is always good value, and usually entertaining.  His style of "debate" is consistent, and I can't recall any climate denier getting the better of him.  The typical denialist is psychologically stuck in concrete and won't change or admit error . . . but there will always be some ambivalent onlookers (who may well be swayed by Potholer's fact-based line of reasoning).

    Potholer is currently up to 52 videos on climate; plus many on Evolution; and a few more general ones of interest.

    WUWT  is a fascinating study in itself, demonstrating the abysses of human intellectual insanity, in rampant form.  But I am undecided whether it is a force for evil, in magnifying & "echo-chambering" the nonsense and anger of the anti-science extremists & paranoid Conspiracy Theorists . . . or whether it is indirectly a force for good (in allowing a public venting-space for wackos who would otherwise spend time elsewhere, physically "acting-out" their anti-social urges).

    As MA Rodger mentions above, the denialists seem to be gradually trying to re-classify themselves as Climate Realists.   Laughable, to be sure . . . but let's hope such semantic shenanigans will keep them occupied in establishing their own consensus about their "label" (instead of getting up to more mischief in the public space).

  12. Eclectic @ 886

    Thank you for the suggested video. 

    I truly enjoy Potholer54's YouTube Channel.  He recently posted a Coronavirus: Science vs. politics video that was informative and entertaining.

  13. Hi, I have a question about peer reviews.  Are there lists somewhere that show who has peer-reviewed studies/papers being mentioned?  For example, I have been searching for peer reviews of Naomi Oreske's consenus study, but I'm not having any luck?  Any places you can point me to?  When offer these studies at online discussions, I invariably get linked to critiques given by bloggers.  Of course, these bloggers, being climate deniers offer all sorts of claims of dishonesty and bad studies, but it seems like if these studies where peer reviewed, those reviews would hold much more water than a denier blogger with no real expertise in climate science...

  14. Karlengle: "Peer review" of submissions for scientific publication usually is done double blinded--the reviewers don't know who the authors are, and vice versa. Authors are given the reviews regardless of the final decision of acceptance or rejection by the journal or conference. For many decades, those reviews remained private, as a way to support frankness. But some publications are changing the model to open reviews.

    (In fact, at this very moment, I am in hour 10 of 12 hours of a conference subcommittee meeting--fortunately three sessions of four hours. All 37 subcommittee members are watching discussions of each submitted paper by two of those members, summarizing each paper's review by them plus by two to four reviewers who are not on the subcommittee. Substantial effort went into carefully recruiting those two to four external reviewers, curating discussions among those reviewers to clarify disagreements in their reviews, and crafting demanded or suggested revisions to the authors.)

  15. Karlengle: Perhaps I misunderstood your question. I thought you asked to see the peer reviews of the publications. Are you instead asking how to tell whether a given publication was peer reviewed?

  16. Note there is more the Naomi Oreskes paper here. It is not clear to me from the context whether the Oreske article was peer-reviewed. Editorial-type and some review pieces in Science journals are not always peer-reviewed, though papers are in Science. However, the Oreske paper was in section called "essays on science and society". Since it was presenting an actual analysis rather than comment, I would guess "yes", but it isnt that clear.

    The Oreske conclusion is not substantively different from other peer-reviewed studies of consensus however. It is extremely difficult to challenge the conclusion that a very strong scientific consensus on AGW exists from the evidence.

  17. Tom Dayton, Thanks for the insight into the peer review process!  Sounds pretty grueling... 

    I was asking because one of the main responses I get from deniers when I give the studies on consensus, are links to notable deniers going into details on their own reviews about the studies always claiming a smoking gun of trickery and deception on these studies.  One usually has to get pretty deep in the weeds to dispel those.  I always look for the simpler explanation that makes sense to the possible audience of my discussion.  I've usually given up on convincing the other person, but I want to always frame my arguments to appeal to those with a cursury interest and not get mired in the snowing attempts from deniers.  It would be good to argue that denier biased "reviews" of studies are not reliable, and the scientific peer review process is much better at catching bad science.

  18. Karlengle @892

    Have you browsed our TCP homepage about (esp.) our consensus-related studies yet? I'm fairly certain that we by now have answers for all the various attacks lobbed by the usual suspects at them. Most will be answered in the FAQs and others in one of several blog posts and rebuttals published over time and listed a bit further down on the homepage. And there's also The Consensus Handbook with even more information!

  19. BaerbelW @893

    Thanks for the links.  This will definitely add to my toolbox!

  20. Karlengle:

    You may find it informative to read the American Meteorlogical Society's author information web page. They publish several highly-respected journals in various specialities in atmospheric science.

    The review process is described here:

    ...and what they expect from editors and reviewers is here:

    A couple of Skeptical Science pages on peer review:

    The second of those links shows a case where "skeptic" scientists basically did what they keep accusing the mainstream scientists of doing. Another blog post on the same story can be found at ThinkProgress:

    Two more examples of misbehaviour at journals:

  21. That humans are causing global warming is the position of the Academies of Science from 80 countries plus many scientific organizations that study climate science. 

    This is a disingenuous statement.  Of course, 97% of climate scientists believe in global warming, the field of climate science itself was created by a group of people who believed in climate change.  It's literally no different than claiming capitalism in bad, because 97% of communists say so.  It would be similar to creating an academic discipline of hurricane-ology.  It's a one trick pony.  When you have an entire academic discipline dedicated to a single political cause which is funded by a wealthy elite, I tend to be highly skeptical of the intent or motive.

    So, this article has been officially DEBOOONKED!!!

  22. hedron, 

    It is a little difficult to understand your convoluted reasoning and the analogies you provide don't help. There is such a field as the scientific study of hurricanes, it is a specialized area of work for meteorologists. It probably was started by specialists who believed that hurricanes were real. If you don't believe that it is legitimate, substitute your own advice to theirs next time a storm is barreling down the coast of Florida, but to keep honest, leave yourself open to litigation in case your advice leads to loss of life or property.

    "Academies of science from 80 countries" and "many scientific organizations" does not equate to "97% of climate scientist." Furthermore, your analogy does not hold because scientific inquiry is a process whose very purpose is to uncover the stuff that is not a matter of opinion. 

  23. hedron states "Of course, 97% of climate scientists believe in global warming, the field of climate science itself was created by a group of people who believed in climate change".

    This, of course, is complete bollocks. Studies into the nature of climate date back at least as far as the 1800s,

    If hedron wants to inform itself of the history, it can go to Spencer Weart's The Discovery of Global Warming. Based in its brief posting history here, I doubt that hedron will make the effort, though.

  24. The argument presented by hedron @896 is entirely anti-science in that it is saying any area of scientific study can be fake as it can be created to sustain fallacious findings based purely on the belief of those who initiated that area of study and not based on the scientific evidence. If this fake science were possible, all science would be at risk of being slowly stacked full of undebunked nonsense.

    Of course, that is not to say that an individual or small group of resrearchers cannot go off and create a pile of undebunked nonsense. Indeed, many researchers do effectively spend their whole careers so employed. Such work is not of itself anti-scientific as, through the act of bebunking it by others or eventually by those initially involved, the science learns what is and what is not nonsense. The 97% consensus is thus healthy and healthier than 100% as the missing 3% provides an arena for testing the veracity of the 97% and specific to AGW healthy because that 3% is better seen as comprising 30 x 0.1% (as those testing the 97% do not present a singular criticism).

  25. What do you think of the article critizising the 97% number here?

    It's claiming the consensus number is closer to 80% – at least in the study being referred to from 2013 by Dennis Bray & Hans von Storch, (linked to below).

    While 80% is still a strong consensus I must agree with the Forbes article author (Earl J. Ritchie) that:

    "It’s not as easy to discount dissenters if the number is 10 or 15 percent."

    The reason for me asking this is that I'm discussing with a friend whether there's still a debate going on if the climate change is of "natural" origin or if human activity is contributing. I'm arguing that the science is basically settled, but he seems to think it's not since not all climate scientists agree. He was the one giving me that article questioning the 97% claim. Now, I of course think the researchers behind the 97% number presented here on the Sceptical Science site has been thorough and honest, but if there are serveys such as the one below pointing more to 80% agreement I'm wondering how we can be sure the consensus number is around 97%?

    "A survey of the perceptions of climate scientists 2013":

    A comment on the above study from the Forbes article by Earl J. Ritchie:

    "A value of 1 indicates not convinced and a value of 7 is very much convinced. The top three values add to 81%, roughly in the range of several other surveys."


    [BL] Links activated.

    The web software here does not automatically create links. You can do this when posting a comment by selecting the "insert" tab, selecting the text you want to use for the link, and clicking on the icon that looks like a chain link. Add the URL in the dialog box.

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