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The 97% consensus on global warming

What the science says...

Select a level... Basic Intermediate Advanced

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 576 to 600 out of 802:

  1. Mytheroo...  My first question for you would be, have you read the entire paper yet?

  2. Mytheroo....  You can think of it this way: How many research papers that relate to evolution are going to state a position on whether evolution is real or not?

    The more accepted the basic science is, the less papers are going to actually express a position. Thus, Cook et al is saying, of the papers that do state a position, 97% accept man-made global warming.

  3. Mytheroo @575, Cook et al specifically included a secondary rating of a random sample of "neutral" papers to determine if they were neutral becaue the simply did at least implicitly endorse or reject AGW, or whether they were neutral because they endorsed the view that the evidence was inconclusive.  They then took those abstracts that at least implicitly endorse or reject AGW, plus a proportion of all neutral abstracts equal to the proportion in the sub-sample of neutral abstracts that were neutral because they indicated the evidence was insufficient to either endorse or reject AGW.  They report the proportions in each category of this group of abstracts in Table 3, under the column, "% among abstracts with an AGW postion".  The percentages are:

    97.1% endorse AGW

    1.9% reject AGW

    1% uncertain on AGW.

    The percentages among authors of papers are:

    98.4% endorse AGW;

    1.2% reject AGW;

    0.4% uncertain on AGW.

    So, using your terminology, 1.8% of authors of rated papers published papers which are "skeptical", with 25% of those authors publishing skeptical papers which are agnostic, while 75%  published skeptical papers which rejected AGW.

    Those percentages do not directly translate into percentages of the climate scientist population holding particular opinions as some authors published both papers rated as endorsing, and papers rated as neutral.  There is no contradiction in that in that authors opinions may have changed over time, and papers deal with only a small subset of the data, so that an author may in one paper say that a particular subset shows AGW to be true, while in another paper say that the seperate data does not support a conclusive decision.

  4. It's also worth noting (once again, since people seem to so easily miss this important point) that Cook et al is not a survey of scientists' opinions. It is a survey of the positions expressed in the research papers.

  5. You want to see consensus?  I think this is pretty much the definition of consensus!  

    ALL OF THESE Organizations below have independently concured in formal statements (linked at bottom) that CLIMATE CHANGE IS REAL!
    (side note: I would like to see the list of dissenting and denying individuals and organization along with their credentials)

    *Academies of science (general science)
    Since 2001 34 national science academies, three regional academies, and both the international InterAcademy Council and International Council of Academies of Engineering and Technological Sciences have made formal declarations confirming human induced global warming and urging nations to reduce emissions of greenhouse gases. The 34 national science academy statements include 33 who have signed joint science academy statements and one individual declaration by the Polish Academy of Sciences in 2007.
    (listed in detail at bottom)
    *American Association for the Advancement of Science as the world's largest general scientific society
    *Federation of Australian Scientific and Technological Societies
    *United States National Research Council
    *Royal Society of New Zealand
    *The Royal Society of the United Kingdom
    *African Academy of Sciences
    *European Academy of Sciences and Arts
    *European Science Foundation
    *InterAcademy Council As the representative of the world’s scientific and engineering academies,
    * International Council of Academies of Engineering and Technological Sciences
    * American Chemical Society
    * American Institute of Physics
    * American Physical Society
    *Australian Institute of Physics
    * European Physical Society
    * The American Geophysical Union
    *American Society of Agronomy (ASA),
    *Crop Science Society of America (CSSA),
    * Soil Science Society of America (SSSA)
    *European Federation of Geologists
    *European Geosciences Union
    *Geological Society of America
    *Geological Society of London
    *International Union of Geodesy and Geophysics
    *National Association of Geoscience Teachers
    *American Meteorological Society
    *Australian Meteorological and Oceanographic Society
    *Canadian Foundation for Climate and Atmospheric Sciences
    *Canadian Meteorological and Oceanographic Society
    *Royal Meteorological Society (UK)
    *World Meteorological Organization[edit]
    *American Quaternary Association
    *International Union for Quaternary Research
    *American Astronomical Society
    *American Statistical Association
    *Engineers Canada
    *The Institution of Engineers Australia
    International Association for Great Lakes Research
    *Institute of Professional Engineers New Zealand
    *The World Federation of Engineering Organizations
    American Association of Wildlife Veterinarians
    *American Institute of Biological Sciences.
    *American Society for Microbiology
    *Australian Coral Reef Society
    *Institute of Biology (UK)
    *Society of American Foresters
    *The Wildlife Society (international)
    *Albania: Academy of Sciences of Albania
    *Armenia: Armenian National Academy of Sciences
    *Australia: Australian Academy of Science, *Australian Academy of Technological Sciences and Engineering,
    *Australian Academy of the Humanities, Academy of the Social Sciences in Australia, National Academies Forum
    *Austria: Austrian Academy of Sciences
    *Belarus: National Academy of Sciences of Belarus
    *Bosnia and Herzegovina: Academy of Sciences and Arts of Bosnia and Herzegovina
    *Bulgaria: Bulgarian Academy of Sciences
    *Canada: Royal Society of Canada
    *Cambodia: The Royal Academy of Cambodia
    *People's Republic of China: Chinese Academy of Sciences, Chinese Academy of Social Sciences, Chinese Academy of Engineering, Chinese Academy of Medical Sciences
    Croatia: Croatian Academy of Sciences and Arts
    *Czech Republic - Academy of Sciences of the Czech Republic
    *Denmark: Royal Danish Academy of Sciences and Letters
    *Estonia: Estonian Academy of Sciences
    Finland: national academies based on language. The Finnish Academy of Science and Letters
    *France: the Institut de France groups together five academies, including the Académie française
    *Germany: Leopoldina
    *Greece: Academy of Athens
    *Hong Kong: Hong Kong Academy of the Humanities
    *Hungary: Hungarian Academy of Sciences *Ireland: Royal Irish Academy
    *Israel: Israel Academy of Sciences and Humanities
    *Italy: Accademia dei Lincei for sciences, *Japan: The Japan Academy
    *Macedonia: Macedonian Academy of Sciences and Arts
    *Netherlands: The Royal Netherlands Academy of Arts and Sciences
    *Norway: The Norwegian Academy of Science and Letters
    *Pakistan: Pakistan Academy of Letters, *Pakistan Academy of Sciences
    *Poland: Polish Academy of Sciences, Polish Academy of Learning
    *Portugal: Academia das Ciências de Lisboa
    *Republic of China (Taiwan): Academia Sinica
    *Romania: Romanian Academy
    *Russia: Russian Academy of Sciences
    *Scotland: Royal Society of Edinburgh
    *Serbia: Serbian Academy of Sciences and Arts
    *Slovenia: Slovenian Academy of Sciences and Arts
    *Spain: The Royal Academy
    *Sweden: Swedish Academy for language, Royal Swedish Academy of Sciences
    *Thailand: Royal Institute of Thailand
    *Turkey: Turkish Academy of Sciences
    *Ukraine: National Academy of Sciences of Ukraine
    *United Kingdom: the Royal Society
    *United States: National Academy of Sciences (NAS), the National Academy of Engineering (NAE), the Institute of Medicine (IOM), and the National Research Council (NRC).
    *Vatican City: Pontifical Academy of Sciences

    Links to statements at:

  6. Having now read the entire survey, a question arises whereby the 97% figure eventuated, I was wondering why there wasn't a 100% agreement of the 32.6% of abstracts that thought humans influenced climate? Also the 66.4% of the 11944 abstracts looked at, that expressed no position on AGW seem to have been dismissed out of hand. My reading of the survey of all the climate abstracts, puts the consensus on AGW at more like 33%. Why is it that the abstracts studying climate held no position, are not included in the overall result? I am genuinely mystified as how a figure of 97%  endorsing AGW, when 66.4% of abstracts of  11944 held no position at all on AGW.

    If this too hard to explain here you can privately email me so I can have a clear understanding of what is going on.

  7. Following on 581 Steve B, I would like to know how many of the abstracts explicitly endorse that humans caused most of the global warming? From what I understand of the data, there were only 75 such abstracts. Correct me if I am wrong. I am a newbie and not terribly scientific, but I understand numbers. Would someone care to explain?

  8. Is there any hope of getting the true facts bout the mythical 97% like just how many climate scientists there are and which way they voted?


    [JH] Read Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature. if you have further questions on this topic, post them there.

  9. Realist308 - this article is showing that the statement "that there is no scientific consensus" is false. You are entitled to believe that all those scientists could be wrong but I wonder whether you have same opinion on all those scientific theories on which there is a consensus? If your Dr tells you have x disease and the scientific consensus is that you need Y to save your life, do you go with the consensus or the crank who tells you it can fixed with magnets?

  10. @scaddenp - Unfortunately, your analogy isn't a good one.  30 years ago the consensus scientific opinion in the medical community was that stomach ulcers were caused by lifestyle and stress factors.  Two "cranks", Drs. Barry Marshall and Dr. Robin Warren, postulated that bacterium H. pylori was the culprit.  What was the initial reaction in the medical establishment?  Castigation and excoriation.  This lasted for years until both doctors were eventually exonerated by the community and went on to win the Nobel prize in medicine!  Egg, meet face!

    The bottom line here is that consensus, in and of itself, means little in terms of correctness and accuracy.  It is a weak framing of the issue because it is a defensive mechanism that allows scientists to take comfort from a "safety in numbers" approach.  Invoking the "consensus shield" is anathema to science, to which healthy questioning is the lifeblood of discovery.

    The approach of directly debunking skeptic claims through evidenciary proof is much more effective than hiding behind consensus.  I think the AGW community does itself a disservice by touting consensus as loudly and as often as it does. It detracts from the better tactic of taking the issues head-on, case by case.

    The day we stop questioning consensus is the day science dies.

  11. Prosensus @585.

    Do you not think your own analogy is itself pretty rubbish.

    Firstly Marshall & Warren developed they hypothesis in 1982. Twenty-three years later they had been awarded the Nobel prize for Medicine. Of the contrarian work in climatology, I see no candidate whatever worthy of any sort of award or commendation. And how long have these numpties been at it?

    Secondly, while Marshall & Warren fought against a consensus, that concensus was not itself wrong as people do get ulcers and stomach cancer because of stress. What the concensus was missing was that there was a microbial cause also acting. It was because 50% of humanity are infected with that microbe and the vast majority do not suffer ulcers that gave Marshall & Warren such an up-hill battle.

    You appear to be arguing that humanity should ignore science because there are always questions for science to answer. Such an argument is nonsense.

  12. Prosensus, you need to look at the bigger picture.  Galileos are extremely rare, but crackpots are extremely common.  Marshalls and Warrens are a bit less rare, but they are still way outnumbered by scientists that make bit claims that go against the scientific mainstream in their fields, but who are simply mistaken (e.g. Wakefield, Essenhigh, Salby etc.).  The existence of people like Marshall and Warren illustrates that the existence of a consensus is not absolute proof of anything, but it also doesn't mean that consensus is not good evidence of something being true.  You need to look at the relative frequencies of the consensus being correct and it being incorrect.  Sadly the cases where the consensus is correct (e.g. Salby) tend not to go unreported.

    Nobody is "hiding behind consensus" (frankly that is just the sort of rhetoric we could all do without).  The value of the consensus is demonstrated by the fact that the skeptic scientists keep going on about the lack of consenus, which led to papers like TCP.  Science generally isn't concerned with consensus as the scientists are able to form an informed opinion on the topic for themselves.  The same is not true of the general public, who don't have the scientific background to do this on every topic, which is one of the reasons we have scientific bodies such as the Royal Society, the Royal Statistical Society, the IPCC etc, which show where the mainstream scientific position lies in a way that can be appreciated by the general public.

    "The day we stop questioning consensus is the day science dies." this is a nice soundbite, but nothing more.  If by "we" you mean the general public then the statement if obviously incorrect, science can operate perfectly well without external questioning.  If "we" meant the scientists, *they* are not very interested in following the consensus, the cutting edge is where advances are made, so "questioning the consensus" is their day job.

  13. Prosensus:

    Here is how Barry Marshall described his first presentation of his hypothesis about H. pilori in 1986:

    "Barry Marshall: Well, I was fairly confident at that stage, and I was sticking my neck out.

    I knew there'd be a lot of Americans there. And we were then challenging for the America's Cup. And so, in fact, I got up and I really threw down the gauntlet. My first slide was a photo of Perth in Western Australia, lovely river and sea, and a yacht. And I said, "This is Perth, Western Australia, and this is the yacht that's going to win the America's Cup in 19..." I think it was '86 or '87. And everybody, "Ahh!" You know, paper balls were being thrown at me. And then I went on to present the new bacteria. I wasn't totally alone though, because I had connected up with the head bacteriologist in England who was interested in that species or that type of bacteria. I'd visited with him for a couple of days before the conference and he had kind of given me a little more confidence than usual, and backed me up on it. As he introduced me, he said, "Well, this is Barry Marshall. He's got this wonderful, interesting new bacteria." So although people were skeptical, and they all went home with the aim of trying to prove me wrong, that's how science moves forward. Someone has a hypothesis and you say, "Okay, if I can prove it wrong, I can publish a paper saying he's wrong." Gradually, over the next few years, one by one, these people trying to prove me wrong fell by the wayside and actually converted over to my side, and became experts in their own right, in helicobacter." source

    Doesn't seem to me like "castigation and excoriation."  He received the Warren Alpert Prize in 1994, only 8 years later, from the Australian Medical Association.  Sounds more like the data was fairly checked and accepted, as you would expect for any new claim.  Can you provide a cite to support your wild claim that Marshall was not treated fairly???  It would mean more if you can support your wild claims.

  14. I'm kind of curious if anyone can show that the mainstream medical science position on gastric ulcers prior to Warren & Marshall's work was anything like as well-supported by evidence or as well-endorsed by the practicing researchers of the time as the scientific consensus of global warming is today.

    The interview with Marshall that michael sweet linked to suggests such is not the case, which is likely another reason why the case of Helicobacter is a poor choice in attacking the scientific consensus on global warming.

    Another relevant passage from the interview:

    One of the things that happened with me is that I was interested in computers, even in 1980 with e-mail, but it was really teletypes in those days. Our library had just got a line to the National Library of Medicine. So I came in and started doing literature searches, because I was interested in computers and it was fun for me. But I started trying to track these bacteria. And I found various, very widespread, dispersed references to things in the stomach, which seemed to be related to the bacteria, going back nearly 100 years. So that we could then develop a hypothesis that these bacteria were causing some problem in the stomach, and maybe that was leading to ulcers. And then, instead of having to do 20 years of research checking out all those different angles, the research was done, but it was never connected up. And so, with the literature searching, as it became available, we were able to pick out the research that was already there and put together this coherent pattern, which linked bacteria and ulcers. It didn't happen overnight. We actually thought about it for two years before we were reasonably confident. It was really quite a few years before we were absolutely water-tight.

    (Parenthetically, Marshall goes on at some length about how he likely could have made more progress advancing the hypothesis if he himself had been more diplomatic.)

  15. posted a comment, did it get deleted?  if so could someone point out why so I'll be able to better form future comments?


    [Dikran Marsupial] Your posts were indeed deleted, due to sloganeering.  Please see the comments policy and adhere to it.  SkS is a good forum for rational discussion of science, but rhetoric and inflamatory tone tends to be counterproductive, so please dial back the tone.

  16. OK so my original comment got deleted so I'll just go one fact at a time and see how things go. First I'm not a climate change denier, I'm skeptical of both sides particularly because so many of the key players have a profit motive. My interest here is to find out the truth based upon as much hard science as possible and not be side tracked by spin, emotionally driven or financially motivated agenda's.

    First, I question the message of the big red logo declaring "97% of climate papers agree that global warming is happening and we are the cause". Climate change is happening, I don't know anyone who disagrees so stating that as part of an argument tends to lend itself to the logical fallacy of false implication.

    The logo clearly implies that we are either the only cause or the major cause of global warming but that is definitively not what 97% of climatologist or climate papers state. The implication of the conclusion does not match the data and the fact no one on this site is addressing that fact makes the conclusion seem greatly biased.

    To give an example of my point, I think if you had a bunch of peer reviewed science on premature causes of death in adult males in the united states you would get 100% consensus that car crashes cause deaths. If you then made a logo that stated 100% of scientific papers agree that car crashes are THE cause of premature death in adult males in the united states would that be an accurate way to use the data?

    Is there a report/study of the number of climate papers or climatologists who are publicly stating that humans are the primary or sole cause of the climate change? I have done a lot of reading on this site but have not found that study. Additionally the fact it's being repeated adnauseum makes it seem like there's a conscious effort to eliminate skepticism through the use of that logical fallacy (ad nauseum) as well.

    Though I agree CO2 emissions do appear to have a potential causation in some of our climate change (the only fact here is correlation and real scientists know that causation and correlation are not the same) but there is lots of data that is contrary to this assertion. From 1900 until 1940 temperature was dropping despite the unmitigated rise in CO2 levels. That doesn't make a lot of sense if AGW is the major cause of global warming.

  17. bakertrg Your car based analogy is misleading because there are many causes of premature death, but there are only two possible causes of climate change, namely anthropogenic or natural (or a combination of both).  If a paper takes the position that climate change is predominantly anthropogenic, that is implictly taking the position that is is (at least mostly) not a natural phenomenon.

    97% of the papers that take a position on the question do take the position that it is mostly anthropogenic.  The papers that do not take a position on the question (and the vast majority of papers on climate change do not) shed no light on the question and hence are not included.

    If you want a study of scientists that are publicly stating that humans are the primary cause of climate change, then you won't find one, because scientists have better things to do, however as a start, you could just list the names of the authors of the IPCC WG1 reports (there are a lot of them).  Then you can add the authors of the statements made by the scientific bodies that Daniel Bailey mentions

    As to your last paragraph, if you think that correlation is the only reason we have to think that CO2 causes climate change, you are mistaken (or at least your information is out of date by at least 70 years, the phsyical mechanism of the greenhouse effect was worked out in detail by Calendar and Plass in the 1950s and 60s).  If you think that the greenhouse effect does not exist, then I suggest you read Roy Spencers list of skeptic arguments that don't hold water (in particular item #1).

  18. Climate change is happening, I don't know anyone who disagrees so stating that as part of an argument tends to lend itself to the logical fallacy of false implication.

    There's a TV program discussing the failure of climate-related legislation to work its way through the US Congress in 2010-2011. Sadly I do not recall the name, although I believe it is featured here on Skeptical Science.

    One of the spots in the program showed Christopher Monckton egging on a Tea Party rally in, if memory serves, 2010 during the run-up to the Congressional elections.

    On at least one occasion, Monckton gets the crowd to chant that global warming/climate change is a hoax. (This ties in to the recent "quantum nature of climate science denial" that John Cook posted about, as Monckton is also on video record saying that global warming is caused by the Sun.)

    If you really don't know anyone (or know of anyone) who has denied that global warming/climate change is really happening, you aren't reading enough Internet comment threads IMO.

    I'm skeptical of both sides particularly because so many of the key players have a profit motive.

    Go to your closest university with atmospheric physics department and look at the cars the scientists drive.

    My interest here is to find out the truth based upon as much hard science as possible and not be side tracked by spin, emotionally driven or financially motivated agenda's.

    Okay then, go read the IPCC AR5, or maybe the US National Climate Assessment.

  19. I'm not sure why you seem to think otherwise, but I totally agree on the CO2 being part of the greenhouse effect, my argument is the change in CO2 is not convincingly correlated to climate change on the level that is being put forth.

    So we're clear, everyone is in agreement that the climate is currently shifting warmer and the greenhouse effect is a real thing. The dispute is if man made emissions are causing that shift more than nature. There really is very little evidence to support the claim that it's (CO2 emissions) causing global warming on a massive scale when we're simply not experiencing global warming beyond what has repeatedly been experienced in the past.

    As of 2001 humans had only changed the CO2 levels by 100ppm, I'm sure it's 200 ppm or more by now (I read somewhere we're increasing the number by 2 ppm per year but forgot where), but 200ppm is a miniscule fraction of the greenhouse gases as compared to water vapor for instance. Once again if CO2 is such a sure thing for causation (not simple causation but THE significant causation) how was temperature dropping in the early 20th century despite rising CO2 levels? I fully understand the greenhouse effect, that's not the debate the debate is that the relatively small change in greenhouse gas density is massively impacting global climate and that AGW is definitively the cause of a massive change even though we're still in a place that is fully within the expected variance defined by historical record.

    Does that make sense? Your argument is that we're in a massive man made climactic shift but we're not even outside the boundaries of what we have regularly seen in the past, when man made influences were not present. Kind of like making an argument about the massive effects of the steroid era in baseball if no one was actually hitting more home runs. MLB had a sudden statistical shift in home runs by a statistically significant number of players (i.e. the number of players to reach the 500 club jumped massively from like one every 10-12 years to 6 in 10 years) Until we're an outlier statistically, it's very very hard to make your case for causation or to make any case that there is a significant problem.

    I see your point on the analogy, but lumping all natural causes into one set so you can say that there are only two causes is also misleading. Even grouping all the things man is doing (methane from cows, deforestation, fossil fuels, hydrocarbons etc) doesn't do much to isolate the specific things that are really causing the problem if it even is a problem.

    I find it pretty disingenuous to make the argument that scientists "have something better to do..." seems like a convenient story. There are a lot of scientists writing a lot of peer reviewed papers on climate change and arguing they aren't pointing to humans as the primary cause of global warming is basically making my point. If the scientists aren't explicitly stating that the cause of global warming is primarily man made then the 97% graphic is purposely deceptive. You can't have it both ways. Do people who study lung cancer not point to cigarette smoking as a primary/significant cause?

    I'm going to a choose a random subset of those papers because reading hundreds of papers is more time than I have to commit to this but I find it a little suspect that 97% of all climatologist think we're the main cause or that the current state of affairs is indicative of a major problem. It's my gut feeling that if I choose 20 papers randomly and 3 or more of them don't explicitly state they feel anthropomorphic causes are the main cause of global warming then the 97% number is very suspect, I could do the probability of that happening but even without doing the math I know it's pretty small. I can also figure out what a statistically relvant sample size if I need to but I have a feeling if I read 20 of the papers I'll get very large delta from the 97%.

    Dr Roy Spencer's web page CLEARLY states that he feels the majority of global warming is NOT anthropomorphic. You can read about it here, it's clearly stated in his main navigation...

    Roy Spencer also dispute Gore and his man Hansen that global climate sensitivity is high (which is a big factor in the alarmist nature of the global warming message).

    Pointing to point 1 on that site (that you have apparently not read in any detail) is a red herring. My argument is not that there is no greenhouse effect, my argument is that there is very little evidence to suggest the change in CO2 created in the last 100 years is the significant factor in changes in climate.

    IPCC recently admitted that their earlier claims about the rate of global warming were grossly overstated. (alarmist sensationalism) they also admitted they can not explain the current plateau in temperatures and their models all predicted twice the change than we're experiencing. Basically admitting their models are not strong and their position is flawed all in one fell swoop.

    Additionally Spencer shreds the IPCC for using models that don't find natural causes because they are explicitly designed to search for man made causes. Kind of have to be careful who you're citing as a source for your position when the majority of what your source has to say massively supports my position.

  20. bakertrg wrote "I find it pretty disingenuous to make the argument that scientists "have something better to do..." seems like a convenient story."

    sorry, *I* have better things to do than attempt to discuss science with those that immediately accuse me of being disingenuous because they can't answer the point.

    Now if you feel that there is evidence that shows that the rise in CO2 has not resulted in an increase in temperature, then please present that evidence on the appropriate thread (this one is for discussion of the concensus, not the phsyical science).  But please do so without the hyperbole, I am interested in science, I am not interested in rhetoric.

  21. composer you're equating two things that are not the same.  No one credible is stating climate change is not happening, the quote you have regarding "global warming is a hoax" is in regard to the alarmist global warming mantra being pushed by Al Gore and the like.  That it's a man made phenomenon (AGW if you will) and threatening to destroy the planet.  So matural climate change is definitely happening the argument is are we expereincing potentially devestating global warming that is man made, irreversible and a serious threat to life as we know it.

    When I said no one is arguing that climate change is happening I was refering to the never ending cycle of climate shifts the earth has seen. We're currently in a warming cycle but this has happened repeatedly for as far back as we can find evidence (trees in the geologic short term and ice cores for a more extended view.)

    One of the confusing things on this subject is the interchanging of terms "global warming" and "climate change".  I'm guilty of this myself, typically global warming or Anthropomorphic Global Warming (AGW) has a negative connotation and puts the cause of change squarely on man and typically makes the supposition that the change is massive and catostrophic.  

    The IPCC is not convincingly unbiased, I have read much of what they have to say but they have been impugned on numerous fronts, not to mention they attempted to sweep data that undermines there arguments under the rug.  That's not good science.

  22. bakertrg @594, running of a list of trivially easy to refute denier memes is hardly going to convince us that your front as a sincere inquirer is genuine.  Rather than run through the whole GISH gallop, I will take just one:

    " was temperature dropping in the early 20th century despite rising CO2 levels"

    I assume you are not going to pretend that you were asking us to explain something which you believed to be false.  Ergo you have claimed that temperatures have fallen over the early twenty first century.  So, by what measure?

    I'll make it easy for you.  In the upper left margin you will find a button labelled "trend calculator".  Press it, and tell me which of the temperature records shows a negative trend in the 21st century.  Tell me the data set, the start date and the trend.

    If you cannot find one, publicly admit that you have made a trivially false claim that was easy to check.  You have in fact proved that your critical faculties work only one way in this debate.  Admit that to yourself and you may have a chance of becoming genuinely skeptical.

  23. Tom Curtis,

    NOAA, HADCRUT4, & RSS.  Start date 2001, end date 2014 all give neg trends.

  24. bakertrg - That's quite a Gish Gallop of disproven memes you've posted, and indicate that you have not been reading up on the topic. I would suggest looking through The Discovery of Global Warming by Spencer Weart, which is quite approachable. 

    Long story short, if you are actually interested in the science, I suggest you read up. Your claims are seriously in error. 

    If you are interested only in dismissing the conclusion that we're responsible for climate change (as hinted at by the amount of rhetoric in your posts) you're barking up the wrong tree. The overwhelming consensus on the topic is due to the overwhelming evidence supporting it, and reality cares not one whit about your preferred conclusions. 

  25. franklefin:

    bakertrg wrote the early 20th century, so I am assuming that Tom Curtis meant to issue his point with respect to that timeframe, and the change in centuries is inadvertent. But Tom can clarify if I'm wrong.

    (I'm sure one can find a brief cooling trend here and there in the early 20th century, perhaps even a statistically significant one - in fact, I used GISTEMP from 1900 to 1910 and got a trend of -0.270 ± 0.263 °C per decade over that timeframe. But the point of the exercise is to get bakertrg to actually support his arguments.)

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