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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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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

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 276 to 300 out of 908:

  1. I wonder if the "consensus" among AGW supporting scientists is the basic need for government subsidized studies of the supposed "problem?"
    Response: [Daniel Bailey] Please refrain from expressions of ideological bias; stick to the topic of the post. Off-topic comments will get deleted. Thanks for your compliance!
  2. Interesting news, identifying how some of those non-consensus scientists get their funding. Waxman Asks Upton to Examine Dr. Patrick Michaels’s Testimony Dr. Patrick Michaels of the Cato Institute testified that widely accepted scientific data had “overestimated” global warming and that regulation enacted in response to that data could have “a very counterproductive effect.” ... In its “Morning Energy” column, Politico described a CNN appearance by Dr. Michaels in which he gave “40%” as his estimate of how much of his funding comes from the petroleum industry. But that would never compromise their opinions.
  3. The study mentioned in this article, Doran and Zimmerman 2009, is a very poor study. The survey questions asked are so crafted that nearly everyone, regardless of opinion on AGW, would answer yes. To prove it, Dr. Lindzen and Dr. Michaels both answered positively to the survey, even though they are routinely considered 'deniers'. Details are in this article: Study claiming ’97% of climate scientists agree’ is flawed
  4. @281 Interesting! with that in mind, what is you opinion concerning the "petition project" signed by some 31,000 scientists 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"?
  5. #282: "concerning the "petition project"... " See the thread on the very same petition project. When the petition first came out, I checked some of the names: Quite a few dentists, pediatricians, astrologers, people who had taken a science degree and then gone on to business school or law school ... even some who were deceased at the time.
  6. muoncounter, Yes, I'm well aware of the lack of credibility of the "petition project" list. That's why I asked the question in light of the statements in #281. I wanted to see if he supported the "petition project" but not the Doran study. Or perhaps I misunderstood what he was suggesting.
  7. As a person who tries to keep informed about the Climate Change issue, I can't help but view the pro-AGW group as the early 15th century Holy Roman Catholic Church, and the anti-AGW group as Galileo. The East Anglia emails show the extent that pro-AGW group will go to hide dissent. (The application of pressure on journals to fire editors who dare to publish contrary opinions: the modern day equivalent of burning heretics at the stake). The same emails indicate that the data is being manipulated to show warming that is no longer occurring. AGW scientist won't/are scared of showing their algorithms, etc… The failure of the pro-AGW groups to have honest and open debates, and the active attacks that this same group perpetrates on scientists with different opinions is more than enough reason to disqualify this science. I know many Christians that are more open to debate and discussion about their religion and faith, than AGW-advocates are about their ‘science.’ As an outsider, I also shake my head with dismay as this whole science has become a moving target over the years. The earth is warming and that's a fact. Oops the upper levels of the atmosphere aren't warming. Ahem, well that is part of our theory, yeah it really was. Oops, only the troposphere at the very lowest levels is supposed to warm. Yeah, that's the ticket. Oops, these temperature levels are declining. Ok, let's manipulate the data to “hide the decline” and attack all the deniers and rename it "Climate Change." Ok, it is going to get so hot, that it really cooling off. Look folks it is so complicated that only the truly smart can understand climate change. Who are the truly smart? Well, they are whoever we say they are. Climate Change is what we say it is.
  8. NA #285 Thank you. If you spend too much time looking at the evidence for AGW it can sometimes become a little depressing but your post made me laugh out loud.
  9. Thanks, Neobot. Of course, the crucial difference is that Galileo had evidence and all the Church had was faith. It's also not so complicated nor so filled with doubt.
  10. Oh, and just in case you are actually human, Neo, perhaps you'd like to read and move your comments to a more relevant thread.
  11. Neo, I think you are misinformed on a few of the topics. Regarding you issue with "hide the decline", the decline is not in the temperature record but rather in the divergence in the tree ring record. You'll find a good summary of the issue here The temperature record using modern instruments have shown very good agreement, and have with stood independent reconstructions. See here for details. In fact recently the BEST project ran by Richard Muller, who is hardly pro-AGW, showed agreement with the other temperature series. "The East Anglia emails show the extent that pro-AGW group will go to hide dissent. (The application of pressure on journals to fire editors who dare to publish contrary opinions: the modern day equivalent of burning heretics at the stake)." Here is a good summary of the issue surrounding the allegation. "Look folks it is so complicated that only the truly smart can understand climate change." This cannot be farther from the truth. While some aspects are no doubt highly technical, the theory on the whole is very approachable. What is required is the patience to go though all the details, because a LOT has been done. Most of the skeptics "objections" you hear nowadays is nothing new, and they all have been considered at some point (some long time ago).
  12. Neo Anderson wrote : "As a person who tries to keep informed about the Climate Change issue..." Unfortunately, everything you typed after those words shows that you have failed in keeping yourself informed, except in as much as you seem to have 'informed' yourself via the medium of websites of denial, misinformation and disinformation. However, it is never too late to start, so try these links : Newcomers Start Here The Big Picture List of Skeptic Arguments
  13. Actually Galileo is more cited than known. I'd invite to study history a bit more in depth before making any analogy. Should we consider this as a modified version of the famous Godwin's law?
  14. Neo... Your post begs the question, where are you trying to keep informed on climate change issues?
  15. Riccardo, There's actually a name for this tactic, it's called the Galileo gambit.
  16. That's a good one, e. And, having read your link, I was distracted by another link there : the Chewbacca Defense. I think we have seen that over on the 2nd law of thermodynamics contradicts greenhouse theory thread, including the related Chewbacca Dilemma, as shown by those trying to explain the facts to those who don't seem to be able to understand them !
  17. e doh! Thank you. I think I'm going to use it often ;)
  18. I like the way Carl Sagan summed it up: "But the fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright brothers. But they also laughed at Bozo the Clown."
  19. #287: My point was that the church had the consensus and they vigorously defended it to the detriment of science. Further, perhaps my analogy was a little too subtle, but to some, AGW has become its own religion. It has to be taken on faith. Also #287, you can watch videos on YouTube of AGW scientists such as Mann, Hansen, etc… getting in arguments over exactly what the consensus is. #289: It is documented that weather recording sites were moved from the open country to city parking lots. There was apparently much frustration at the lack of temperature increase in much of the southwestern United States. I guess it has now proven that parking lots and rooftops are much warmer than the countryside. Years of potential valuable data was destroyed. A few of these sites can be viewed at norcalblogs. Also #289, I agree that the “objections” were looked at some point in the past. However since they were contra-AGW, they were dismissed. After awhile there is so much contra-evidence that I don’t feel it can be ignored. Scientists who consider all of the evidence are labeled as deniers and ridiculed. Would you please list just one study that is accepted by the consensus that contradicts AGW. #290: This is a typical example of what I am talking about. Because I dare read information contrary to the “consensus” I am a heretic. I am not informed. I am now ‘informed.’ #292: Same thing as #290. Once again, the fact I read both sides of the issue implies that I have read the wrong stuff. If I read only the pro-AGW literature, then I would be informed. (And thanks for listing just a few of the sites I have spent much time reading and studying.)
    Response: Please note this site's Comment Policy before posting. Comments are expected to stick to the science and remain on topic. This ensures that the debate remains civil and scientific. The topic here is the scientific consensus regarding AGW. If you wish to discuss the reliability of the temperature record, you can do so in the Temp record is unreliable thread. Future comments in violation of the policy will be edited or deleted.
  20. Neo @297, "Because I dare read information contrary to the “consensus” I am a heretic" No, your posts here do bear remarkable resemblance and have the hallmarks of a troll, and probably violate the house rules Might I suggest you please go back to WUWT or wherever else you have been obtaining your misinformation and anti-science snippets. And for the record, this is my first and last post to you.
  21. Neo#297: "My point was that the church had the consensus" Consensus of what? Consensus of 'this is the way we say it is'; that;s not scientific argument. So that's a nonsensical start. "AGW has become its own religion. It has to be taken on faith." And now a descent into the ridiculous; this is called science, not faith. It is far more of an act of faith to blindly accept that AGW is not happening. Go to WUWT and proclaim otherwise; you will be quickly persecuted. Tackle any anti-AGW argument with scientific argument; you will find 'No, its not' is all that's left. So stop the bogus, self-defeating arguments. You'll have to do lots better here.
  22. Neo@297 A point to ponder, if reading information contrary to the "concensus" makes someone a heretic, surely that means all the RealClimate chaps, every contributor to SkepticalScience, Tamino etc. are all "heretics" - there is plenty of evidence that they have read papers by contrarians - how else could they debunk them. This also ought to be awarded a prize for illogical challenge of the week "Would you please list just one study that is accepted by the consensus that contradicts AGW."; if you can't see the logical flaw there, there is a certain irony in your choice of nom de guerre! ;o)
  23. No, Neo Anderson : the church backed a Ptolemaic Model which, although not universally accepted was mathematically provable, and that took the work of several geniuses (including Galileo) to finally discard. Where are those geniuses against AGW ? And where is faith involved, apart from the faith involved in believing that the problem is anything but AGW ? How much proof do you need before someone like you will accept it ? What videos are you referring to ? Where is the documentation you refer to ? Where is the "contra-evidence" ? Which scientists are you referring to ? What "contrary information" do you have ? Who called you a "heretic" ? Did you go to, and read, any of the links you were provided with ? As for your question : "Would you please list just one study that is accepted by the consensus that contradicts AGW." That is strange logic. Let me put this question to you : ""Would you please list just one study that is accepted by the consensus that contradicts Evolution." If you can't, does that mean that Evolution studies are biased against the Creationists and therefore a sham ?
  24. Neo Anderson @ 297... Just because you informed yourself does not mean you have informed yourself with accurate information. Thus my question. Where are you getting your information? Generally, on this site, people cite their claims with links to the information so others can review it for accuracy. Regarding your church analogy... You have to remember that this is science. Science is based on the empirical evidence that has been presented into the literature. When you go to the doctor and get an opinion about a condition you may have, you are generally getting what the "consensus" of most doctors is. You can choose to ignore that and find a minority opinion on your condition if you like. My bet would be with the consensus opinion. The fact remains, the "consensus" on climate change is there and it is robust. The available evidence is overwhelming. It could be wrong, of course. But the chances that it's wrong are vanishingly small. No faith required here. The empirical evidence is fully available.
  25. Neo, Regarding the UHI effect, it has been shown that it doesn't affect the temperature anomaly record. In fact NOAA did a study compared to the ones classified as "good" or "best" according to Anthony Watts, and showed that there is no difference at all. What that implies is that the UHI effect does not create a warm bias. For more details on UHI, I think you should read this , and I am sure people would be happy to have a discussion with you over there. Regarding data distruction, you'll have to be more specific. Regarding alternative theories, they are not dismissed simply because they are contra-AGW, but it is because either they are flawed, there are no supporting evidence, or evidence directly contradicts the theory. On skeptical science you will find a very detailed catalogue of alternative theories, and why they don't work. Most of the "evidences" touted by skeptics are often misconstrued facts, or simply irrelevant to global warming. In addition, scientist that raise scientifically sound objections are always taken seriously in the research circle. It is only when scientists who do not do research in climate brings up points that have be refuted many times that they run the risk of being ridiculed. It gets tiring afterall. "Would you please list just one study that is accepted by the consensus that contradicts AGW." Off the top of my head I remember: Lindzen and Choi 2009 that challenges climate sensitivity. Henrik Svensmark is still publishing on solar cycle-cloud link. Mind you there are only very few of them, precisely because there aren't a lot of scientifically sound alternative theories left.

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