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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

"[...] And I'll mention that the stat on the 97% of - of scientists is based on one discredited study." (Ted Cruz)

At a glance

What is consensus? In science, it's when the vast majority of specialists agree about a basic principle. Thus, astronomers agree that the Earth orbits around the Sun. Biologists accept that tadpoles hatch out from frog-spawn and grow into adult frogs. Almost all geologists agree that plate tectonics is real and you'd be hard-placed to find a doctor who thinks smoking is harmless.

In each above case, something has been so thoroughly looked into that those who specialise in its study have stopped arguing about its basic explanation. Nevertheless, the above examples were all once argued about, often passionately. That's how progress works.

The reaching of scientific consensus is the product of an often lengthy time-line. It starts with something being observed and ends with it being fully explained. Let's look at a classic and highly relevant example.

In the late 1700s, the Earth-Sun distance was calculated. The value obtained was 149 million kilometres. That's incredibly close to modern measurements. It got French physicist Joseph Fourier thinking. He innocently asked, in the 1820s, something along these lines:

"Why is Planet Earth such a warm place? It should be an ice-ball at this distance from the Sun."

Such fundamental questions about our home planet are as attractive to inquisitive scientists as ripened fruit is to wasps. Fourier's initial query set in motion a process of research. Within a few decades, that research had experimentally shown that carbon dioxide has heat-trapping properties.

Through the twentieth century the effort intensified, particularly during the Cold War. At that time there was great interest in the behaviour of infra-red (IR) radiation in the atmosphere. Why? Because heat-seeking missiles home in on jet exhausts which are IR hotspots. Their invention involved understanding what makes IR tick.

That research led to the publication of a landmark 1956 paper by Gilbert Plass. The paper's title was, “The Carbon Dioxide Theory of Climatic Change”. It explained in detail how CO2 traps heat in our atmosphere. Note in passing that Plass used the term "Climatic Change" all the way back then. That's contrary to the deniers' frequent claim that it is used nowadays because of a recent and motivated change in terminology.

From observation to explanation, this is a classic illustration of the scientific method at work. Fourier gets people thinking, experiments are designed and performed. In time, a hypothesis emerges. That is a proposed explanation. It is made on the basis of limited evidence as a starting point for further investigation.

Once a hypothesis is proposed, it becomes subject to rigorous testing within the relevant specialist science groups. Testing ensures that incorrect hypotheses fall by the wayside, because they don't stand up to scrutiny. But some survive such interrogation. As their supporting evidence mounts up over time, they eventually graduate to become theories.

Theories are valid explanations for things that are supported by an expert consensus of specialists. Gravity, jet aviation, electronics, you name it, all are based on solid theories. They are known to work because they have stood the test of time and prolonged scientific inquiry.

In climate science today, there is overwhelming (greater than 97%) expert consensus that CO2 traps heat and adding it to the atmosphere warms the planet. Whatever claims are made to the contrary, that principle has been established for almost seventy years, since the publication of that 1955 landmark paper.

Expert consensus is a powerful thing. None of us have the time or ability to learn about everything/ That's why we frequently defer to experts, such as consulting doctors when we’re ill.

The public often underestimate the degree of expert consensus that our vast greenhouse gas emissions trap heat and warm the planet. That is because alongside information, we have misinformation. Certain sections of the mass-media are as happy to trot out the latter as the former. We saw a very similar problem during the COVID-19 pandemic and it cost many lives.

For those who want to learn more, a much longer detailed account of the history of climate science is available on this website.

Please use this form to provide feedback about this new "At a glance" section. Read a more technical version below or dig deeper via the tabs above!


Further details

We know full well that we don’t have the time or capacity to learn about everything, so we frequently defer to the conclusions of experts. Without experienced people using their expertise to perform many vital tasks – and without new people constantly entering such occupations – society would quickly disintegrate.

The same is true of climate change: we defer to the expert consensus of climate scientists. Indeed, public perception of the scientific consensus with regard to global warming has been found to be an important gateway into other enlightened climate-related attitudes - including policy support. 

Nine consensus studies

Let's take a look at summaries of the key studies, featured in the graphic above, into the degree of consensus. These have been based on analyses of large samples of peer-reviewed climate science literature or surveys of climate and Earth scientists. These studies are available online through e.g. Google Scholar. That slightly different methodologies reached very similar conclusions is a strong indicator that those conclusions are robust.

Oreskes 2004

In this pioneering paper, a survey was conducted into all peer-reviewed abstracts on the subject 'global climate change', published between 1993 and 2003. The work showed that not a single paper, out of the 928 examined, rejected the consensus position that global warming is man-made. 75% of the papers agreed with the consensus position while 25% made no comment either way.

Doran & Zimmerman 2009

A survey of 3,146 Earth scientists asked the question, "Do you think human activity is a significant contributing factor in changing mean global temperatures?" Overall, 82% of the scientists answered yes. However, what was most interesting was the type of response compared to the level of expertise in climate science. Of scientists who were non-climatologists and didn't publish research, 77% answered yes. In contrast, 97.5% of actively-publishing climatologists responded yes. As the level of active research and specialization in climate science increases, so does agreement that humans are significantly changing global temperatures. The paper concludes:

"It seems that the debate on the authenticity of global warming and the role played by human activity is largely non-existent among those who understand the nuances and scientific basis of long-term climate processes. The challenge, rather, appears to be how to effectively communicate this fact to policy makers and to a public that continues to mistakenly perceive debate among scientists."

Anderegg et al. 2010

This study of 1,372 climate science researchers found that (i) 97–98% of the researchers most actively publishing in the field support the tenets of anthropogenic climate change (ACC) as outlined by the IPCC and (ii) the relative climate expertise and scientific prominence of the researchers unconvinced of ACC are substantially below that of the convinced researchers. 

Cook et al. 2013

A Skeptical Science-based analysis of over 12,000 peer-reviewed abstracts on the subject 'global climate change' and 'global warming', published between 1991 and 2011, found that over 97% of the papers taking a position on the subject agreed with the consensus position that humans are causing global warming. In a second phase of the project, the scientist authors were emailed and rated over 2,000 of their own papers. Once again, over 97% of the papers taking a position on the cause of global warming agreed that humans are causing it.

Verheggen et al. 2014

Results were presented from a survey held among 1868 scientists studying various aspects of climate change, including physical climate, climate impacts, and mitigation. The survey was at the time unique in its size, broadness and level of detail. Consistent with other research, it was found that as the level of expertise in climate science grew, so too did the level of agreement on anthropogenic causation. 90% of respondents with more than 10 climate-related peer-reviewed publications (about half of all respondents), explicitly agreed with anthropogenic greenhouse gases (GHGs) being the dominant driver of recent global warming. The respondents’ quantitative estimate of the GHG contribution appeared to strongly depend on their judgement or knowledge of the cooling effect of aerosols.

Stenhouse et al. 2014

In a survey of all 1,854 American Meteorological Society members with known e-mail addresses, achieving a 26.3% response rate, perceived scientific consensus was the strongest predictor of views on global warming, followed by political ideology, climate science expertise, and perceived organisational conflict.

Carlton et al 2015

Commenting that the extent to which non-climate scientists are skeptical of climate science had not so far been studied via direct survey, the authors did just that. They undertook a survey of biophysical scientists across disciplines at universities in the Big 10 Conference. Most respondents (93.6%) stated that mean temperatures have risen. Of the subset that agreed temperatures had risen, the following question was then asked of them: "do you think human activity is a significant contributing factor in changing mean global temperatures?" The affirmative response to that query was 96.66%.

Cook et al. 2016

In 2015, authors of the above studies joined forces to co-author a paper, “Consensus on consensus: a synthesis of consensus estimates on human-caused global warming”. Two key conclusions from the paper are as follows:

(i) Depending on exactly how you measure the expert consensus, somewhere between 90% and 100% of climate scientists agree humans are responsible for climate change, with most of our studies finding 97% consensus among publishing climate scientists. (ii) The greater the climate expertise among those surveyed, the higher the consensus on human-caused global warming.

Lynas et al. 2021

In this paper, from a dataset of 88,125 climate-related peer-reviewed papers published since 2012, these authors examined a randomly-selected subset of 3000 such publications. They also used a second sample-weighted approach that was specifically biased with keywords to help identify any sceptical papers in the whole dataset. Twenty-eight sceptical papers were identified within the original dataset using that approach, as evidenced by abstracts that were rated as implicitly or explicitly sceptical of human-caused global warming. It was concluded that the scientific consensus on human-caused climate change, expressed as a proportion of the total publications, exceeds 99% in the peer reviewed scientific literature.

Myers et al. 2021

This study revisited the 2009 consensus among geoscientists, while exploring different ways to define expertise and the level of agreement among them. The authors sent 10,929 invitations to participate in the survey, receiving 2,780 responses. In addition, the number of scientific publications by these self-identified experts in the field of climate change research was quantified and compared to their survey response on questions about climate change. Perhaps not surprisingly, the study found that agreement on anthropogenic global warming was high at 91% to 100% and generally increases with expertise. Out of a group of 153 independently confirmed climate experts, 98.7% of those scientists agreed that the Earth is warming mostly because of human activities such as burning fossil fuels. Among the subset with the highest level of expertise, these being independently-confirmed climate experts who each published 20+ peer-reviewed papers on climate change between 2015 and 2019, there was 100% agreement.

Public Polls and Consensus

Opinion polls are not absolute in the same way as uncontestable scientific evidence but they nevertheless usefully indicate in which way public thinking is heading. So let's look at a couple taken 13 years apart. A 15-nation World Public Opinion Poll in 2009 PDF), with 13,518 respondents, asked, among other questions, “Is it your impression that among scientists, most think the problem is urgent and enough is known to take action?” Out of all responses, just 51% agreed with that. Worse, in six countries only a minority agreed: United States (38%), Russia (23%), Indonesia (33%), Japan (43%), India (48%), and Mexico (48%). Conversely, the two highest “agree” scores were among Vietnamese (69%) and Bangladeshis (70%) - perhaps unsurprisingly.

The two other options people had to choose from were that “views are pretty evenly divided” (24% of total respondents), or “most think the problem is not urgent, and not enough is known to take action“ (15%). American and Japanese respondents scored most highly on “views are pretty evenly divided” (43 and 44% respectively).

How such a pervasive misperception arose, regarding the expert consensus on climate change, is no accident. Regular readers of this website's resources will know that instead, it was another product of deliberate misinformation campaigning by individuals and organizations in the United States and other nations around the world. These are people who campaign against action to reduce carbon emissions because it suits their paymasters if we continue to burn as much as possible. 

Step forward to 2022 and the situation has perhaps improved, but there's still some way to go. A recent poll, Public Perceptions on Climate change (PDF), was conducted by the Policy Institute, based at King's College London, UK. It quizzed samples of just over 2,000 people from each of six countries (UK, Ireland, Norway, Poland, Italy and Germany). The survey asked the question: “To the best of your knowledge, what percentage of climate scientists have concluded that human-caused climate change is happening?” The following averages were returned: the UK sample thought 65%, the average of the whole survey was 68% and the highest was Ireland at 71%. Clearly, although public perception of expert consensus is growing, there's still plenty of room for strategies to communicate the reality and to shield people from the constant drip-feed of misinformation.

Expert and Public Consensus

Finally, let's consider the differences between expert and public consensus. Expert consensus is reached among those who have studied complex problems and know how to collect and work with data, to identify what constitutes evidence and evaluate it. This is demanding work requiring specific skill-sets and areas of expertise, preparation for which requires years of study and training. 

Public consensus, in contrast, tends to occur only when something is blindingly obvious. For example, a serial misinformer would struggle if they tried running a campaign denying the existence of owls. Everyone already knows that of course there are owls. There is public consensus because we see and hear owls, for real or on the TV or radio. But complex issues are more prone to the antics of misinformers. We saw examples of misinformation during the COVID pandemic, in some cases with lethal outcomes when misinformed people failed to take the risks seriously. There's a strong parallel with climate change: it is imperative we accept the expert consensus and not kick the can down the road until the realisation it is real becomes universal – but utterly inescapable.


Update May 26, 2023: The "At a glance" section was updated to improve readability.

Last updated on 26 May 2023 by John Mason. 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 archive.org)

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:

Lead author John Cook explains the 2016 "Consensus on consensus" paper.

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.

Acknowledgements

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

Update

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

Comments

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Comments 901 to 908 out of 908:

  1. Star-affinity @ #900 :

    Thank you for the reference to the 2016 Forbes  article by Earl Ritchie, who describes himself as a retired oil industry executive (not a scientist).   I read the article with interest, and found it disappointing.  It was more a propaganda piece, and not at all a rigorous logical examination of the issue.

    Star-affinity, if one chooses to define things very loosely, and also use rhetoric like a lawyer-advocate  ~ then one can come to any "conclusion" that is desired.   (e.g. the good Lord Monckton - not at all a scientist - can re-define "3%" to be the result of the excellently clever Cook 2013 survey of scientific papers which produced the famous "97%" consensus figure.)

    What is a consensus here?  (See some of the comments upthread.)   Broadly, consensus in non-scientific matters is all about opinion  ~ and opinion is worth the price of the paper it is printed on [except in politics!]

    But consensus in scientific matters (such as climate science) is all about the evidence.  And that evidence is expressed in the scientific literature (peer-reviewed papers published in reputable journals).   And there you will nowadays  find a 99+% consensus in line with the mainstream science.   Not an 80-90% consensus (not even in 2013 or 2016).

    The 80-90% figure you (or Mr Richie) are mentioning, is a result of canvassing opinions of "scientists"  ~ not of canvassing the evidence.   And who is a scientist?  And are their individual opinions relevant?  The notorious Oregon Petition (of the 1990's) had "scientists" ranging from Wood Engineers to Spice Girls.   In other words, it was a completely worthless survey,  simply gathered for propaganda value.

    In short, Mr Ritchie's article is worthless.

  2. Star-affinity @#900:

    Several other studies have looked at the scientific consensus on human-caused climate change since that Forbes article was published. Here is a blog post from last year written by John Cook about a study he was involved with, replicating Doran & Zimmermann (2009) with a larger sample:

    The scientific consensus on climate change gets even stronger

    The interesting thing with the Forbes' article is, that it has to cherry pick a particular study to make its point of a lower than 90% consensus. And expecting 100% agreement of climate scientists before accepting the evidence is a case of impossible expectations, one of the main science denial techniques covered in the FLICC framework.

  3. BaerbelW  @  #902  :  We can look even further, regarding the Forbes 2016 article mentioned by Star-affinity @ #900 .

    The article's author, Mr Earl Ritchie, has grossly misrepresented the vonStorch 2013 survey  ~ the survey simply does not support Ritchie's thrust of argument.   Ritchie is severely misleading the Forbes  readers - readers who are probably good at business but probably rather unthinking (and ill-informed) on science.   And Ritchie is also misleading them about the Cook 2013 survey of scientific papers.

    The vonStorch 2013 survey [now 8 years old] had its interesting points.  And I think the brief "Mertonian" discussion on pages 68 & 69 was a pleasant change of pace.   And at the end of the survey report, Bray & vonStorch published a long list of comments criticizing the deficiencies of the survey (participants' critiques ~ especiallly about the ambiguities of the survey questions).

    Additionally, please note that the survey had a 7% return rate.  (Vastly different from the Cook 2013 survey, which had a different structure.)

    And, the survey was about opinions ~ and much of it was about opinions on technical aspects/adequacies of climate models & future projections.

    Most of the questions were rather vague and fuzzy and "word based" instead of scientific concept based.  So, somewhat difficult for the participants to express themselves about the overall climate science situation  ~ in analogy: they were invited to give opinion about a leaf or two, but not to discuss the background forest.

    (There were a few exceptions in the questions:  one where 2.5%  of respondents opined that they were not at all convinced about AGW.   And another question, where 89% of respondents said they were now more convinced [versus in 2007] that greenhouse gasses had produced modern global warming.)

    All this compares very poorly with the excellent methodology used in the Cook 2013 assessment of scientific consensus.

  4. Regarding the utility of surveys such as the Oregon Petition mentioned by Eclectic, I always think of Project Steve, which the National Center for Science Education uses to track opinions on the scientific validity of evolution theory. (Wikipedia also has a page on the project.)

    The question basically comes down to whether the selection of individuals responding to the survey is reasonable or not.

  5. Thank you, Bob, for showing the ingenious Project Steve.

    The vonStorch survey [referred to, above] may not have many Steves, but it is a good survey - in the sense that it has a suitable first filter.  It contacts many thousands of appropriately qualified scientists.

    Unfortunately, the low 7% return rate is the first weakness.  It would have been better (but at much greater expense) for expert interviewers to personally meet with a truly random selection of perhaps 200 of the scientists . . . and gently hound them for their views, allowing no-one to drop out or excuse himself!

    At 7% return , there is the reasonable fear that the respondents include a relatively high proportion of "extremists" (from either end of the spectrum).   For example, in one of the questions, 2.5% of respondents replied that they were "not at all"  convinced that AGW existed.   And this 2.5% is an amazingly high percentage, in view of the accumulated overwhelming evidence that the 2.5 percenters are flat wrong.

    In such extreme cases, one suspects that a big slice of the 2.5 percenters have bizarre/extremist political views & a lot of cognitive dissonance.  But 'twas ever thus ~ for almost any field of science.  (Personal anecdote - I know quite well a PhD-level scientific researcher who is a member of his local Flat-Earth Society.)

    And the vonStorch survey questions were very unsuited to elicit actual consensus-relevant opinions.

    Overall, John Cook's 2013 survey of the true scientific literature was the optimum approach to the "consensus" issue.  It was reasonably neutral in selection; it didn't suffer from drop-outs (drop-outs by the busy, or by the disgruntled) . . . and it looked at the actual science , not the sometimes-flaky opinions of us imperfect human beings.

    And on top of it, the Cook 2013 survey doubled-down by asking the scientists personally to confirm (or not) what they viewed their scientific papers as saying.   Brilliant !

  6. In response to Star-affinity @#900:

    Comprehensive responses to the question about the magnitude of consensus regarding human induced global warming and resulting climate changes have been provided by others.

    My initial supplement is: Rather than debating the magnitude of consensus for the theory that “significant anthropogenic climate change is occurring” ask for an evaluation of the level of consensus for the theory that “No anthropogenic climate change impacts are occurring”.

    Increased atmospheric CO2 is unquestionably due to human activity. And increased CO2, along with other human impacts, unquestionably produce global warming and significant, hard to precisely identify, but unquestionably harmful climate changes from the conditions that human civilization developed in through the past several thousand years.

    However, there is more to consider. It is important to be aligned on the context/objectives for a 'debate'. Without objective alignment the result can be a waste of time.

    My primary objective is to try to help develop a sustainable improving future for humanity. Increased awareness and improved understanding of what is going on is essential to sustainable improvement of the future of humanity. And increased awareness of what is harmful and learning how to limit harm done is key, with climate change impacts of human activity being a significant sub-set of concern.

    Science questions things with the objective of increasing awareness and improving the understanding of what is really going on in a way that develops “improved common sense”. It is important for that “common sense” to help improve the future of humanity.

    Note that not all science or application of science is helpful. Misleading marketing is a good example of harmful scientific investigation and application. It can develop cult-like groups of believers with nonsense as “their common sense”.

    Every individual’s perception of what is going on is their reality. All understandings of what is going on are individual beliefs. And everyone has biases regarding what they learn. Everyone develops their understanding based on their experiences in the socioeconomic-political environment they grow up in. In many cases people develop a fondness for, or addiction to, harmful unsustainable developments (systems and beliefs) and resist correction of harm done that they benefit from or hope to benefit from.

    Getting alignment on the objective of “reducing harm done to the future of humanity and developing lasting improvements for humanity” is essential. Without that alignment the discussion can be a competition with the different sides having different sets of rules about how the game is played or judged/refereed. That can be a waste of time.

    Debating details about the level of consensus of understanding that human activity is causing harmful rapid climate change impacts is one of those waste of time games. Establishing that there is significant consensus is important. However, questioning a well developed understanding of the level of consensus is a game being played to delay and distract from the important discussions of how to identify and most effectively limit the harmful impacts of the many developed unsustainable activities that cause climate change impacts.

    One of the most harmful activities is misleading marketing. Always keep in mind that popularity and profitability have no reason to be aligned with limiting harm done. They are measures that are indifferent to harm done . Being more popular or profitable does not mean something is less harmful. In fact, getting away with being more harmful or misleading can be a competitive advantage in games of popularity and profit. And being more popular and profitable can make harmful beliefs and actions harder to correct (the persistence of climate science denial is one of many cases proving that point).

  7. Dr. David Evans made the statement: "Yes, it's important to get our response right. If the alarmist is correct, then we should cut down our carbon emissions of the planet from overheating. If the alarmist is wrong, it's important not to cut back our carbon emissions or we'll create widespread poverty unnecessary.

  8. Sun:

    There is a lot in between the two extremes of "catasrophe" and "no need to do anything". It is not a binary system or "right or wrong" - it is a range of likely outcomes and risks.

    We know with pretty much 100% certainty that adding CO2 causes some warming. For doubling of CO2 (from 300 to 600ppm) it is very unlikely that it will be less than 1.5-2.0C. It will also be very unlikely that it will be more than 4.5-5.0C. But that leaves a lot of range of likely temperature effects that will cause serious changes in climate and very likely serious (and expensive) impacts on society. The larger the temperature change and the impact, the more important it is that we take additional action.

    The idea that CO2 limits will harm the economy is discussed in this thread at Skeptical Science.

  9. why does the original paper list the seven categories but not the seven individual totals. I searched but couldn't find any totals.

    instead it lumps categories 1,2 and 3 into a single number.  So what was the point in having 3 categories?

    but we frequently hear that the paper showed that "97% of scientists believe that humans caused most of the recent warming" which is not true because only 1.6% of papers said that.

    I don't  know of any sceptic who doesn't think humans are causing some warming so they would all be in the 97% consensus.

     

     

     

  10. Albert @909... (yep, there have been almost 1000 comments made on this particular topic)

    a) If you had bothered to read the actual paper it's explained why the figures are organized as they are.

    b) Your 1.6% figure only relates to papers that explicitly quantify human contribution. With that you'd have to compare that to other papers that explicitly minimize human contribution. You can't count, for example, a paper that explicitly quantifies against a paper that implicitly endorses human contribution.

    c) Your comment regarding "some warming" is also a misinterpretation of the paper you haven't read. If a scientist (or paper, in the case of this research... it's an evaluation of published research, not scientists' opinions) were to say they believed humans contributed "some warming" they would be "minimizing human contribution" and therefore included in categories 5, 6, or 7.

    I hope that clarifies this topic for you.

  11. Also @909 you ask, "So what was the point in having 3 categories?"

    Well, again if you read the paper, this is explained.

    The fundamental question this research is asking is about quantifying the scientific concensus on climate change (as the title states). Categories 1, 2, and 3 all endorse the idea that human activities are the primary driving force for warming of the past 50 years (per the IPCC position).

    Conversely, the point is to measure those endorsements of that position against papers that minimize the idea that human activities are the primary driving force for warming of the past 50 years.

    This stuff is really very obvious if you read the paper.

  12. Albert @909 starts off by questioning the groupings in the Cook et al  2013 study, saying that he searched and could not find totals for the individual categories.

    I have linked to the journal article above, and you can scroll down and find the "Supplementary data" link. In that data, one of the files provides every single paper/abstract included in the study, and it's ranking. It's pretty trivial to read that into a spreadsheet and get totals for each group. Those totals are:

    1 Explicitly endorses and quantifies AGW as 50+% 64
    2 Explicitly endorses but does not quantify or minimise 922
    3 Implicitly endorses AGW without minimising it 2910
    4 No Position 7970
    5 Implicitly minimizes/rejects AGW 54
    6 Explicitly minimizes/rejects AGW but does not quantify 15
    7 Explicitly minimizes/rejects AGW as less than 50% 9

    The paper points out that category 4 includes two groups, which need to be treated differently:

    • No position (7930 papers)
    • Uncertain (40 papers)

    "No position" must be excluded entirely, as it is impossible to conclude a position that is not expressed in the paper's abstract. That makes a total of 4014 papers that express an opinion (explicitly or implicitly).

    Given the groupings of 1-3 and 5-7, it is obvious that 1-3 share the trait of "not minimized". It is perfectly reasonable to treat "not minimized" as ">50%", when the paper does not quantify a value.

    Likewise, grouping 5-7 together is the opposite: they all share the trait of "minimizes", whether they have quantified the minimization or not.

    The point of the three categories is to distinguish between explicit quantification, explicit without quantification, and implicit without quantification - on both sides of the equation.

    Now, what about that 1.6% number that Albert throws out? To get 1.6%, you have to pick category 1 (64 papers) and divide by 4014 (the total number that expressed an opinion, explicitly or implicitly).

    So, while Albert is questioning the grouping of papers into 1-3 and 5-7, he sees no problem in grouping 2, 3, 5, 6 and 7 together into one category and calling it "papers that disagree that humans caused most of the recent warming". That grouping is far less supportable than the grouping used in the paper. Categories 2 and 3 (totalling 3832 papers) clearly are not defined in such a way that you can interpret "not minimized" as "<50%".

    In fact, if you only consider the papers that explicitly quantify the effect as >50% or <50%, there are only 73 papers in categories 1 and 7 - and 64 of them say >50% of recent warming is due to humans. That is 88% of the total. A far cry from Albert's 1.6%.

    We can also compare categories 2 vs. 6.  98% are on the "endorses" side.

    And we can compare categories 3 and 5. Again, 98% on the "endorses" side.

    Either Albert has not really considered where the 1.6% value came from, or he is deliberately trying to bias the result in one direction.

    As for his final claim about "skeptics" being included in the 97%, Skeptical Science has another blog post on that matter. Scroll down to the section titled "Confused Contrarians Think they are Included in the 97%".

    Albert is just repeating frequently-debunked crap.

  13. "I have linked to the journal article above, and you can scroll down and find the "Supplementary data" link. In that data, one of the files provides every single paper/abstract included in the study, and it's ranking. It's pretty trivial to read that into a spreadsheet and get totals for each group."

    So why is the "64" not explicitly stated somewhere in the original paper and instead you have to find an obscure file, put into a spread sheet into comma separated columns and include a conditional statement saying if this is category "1" then increment sum.

    so nobody could determine that category "1" had only 64 entries unless they knew how to download the data into a spreadsheet and do a conditional sort.

    So, once again why was there no table listing the categories and theirs numbers?

     

     

    Response:

    [BL] Your pattern of blasting many comments into a thread is forcing me to go into moderator role.

    To begin, please read the Comments Policy.

    As to your "question" - it took me less than an hour to accomplish the task of obtaining the data and determining the numbers in question.

    You have completely ignored the comment I made about the bogosity of your "1.6%" calculation. You are trying to draw attention to a number that does not change the conclusions of the paper.

  14. Once again I ask, why have 3 categories lumped into the "97%" result when only one category saying "explicit or implicit support that humans contribute to global warming".

    Again, virtually every sceptic scientist, meteorologist, geologist, etc would agree with the above statement so they will not be publishing a paper saying there is little or no anthropogenic warming.

    Skeptics believe in the direct effect of CO2 causing an ECS of about 1.2C but reject the positive feedback theory pushing ECS to 3C and beyond.

    So categories 5,6 and 7 are really meaningless, because of the above.

    Quite commonly I see statements saying that Cooks paper said the "97% of scientists believe that humans are largely (>50%)  responsible for global warming" but Cooks paper category 1 clearly and unambiguously states that the figure is 1.6%.

     

     

    Response:

    [BL} None of the categories in the paper use the description you "quote" in your first paragraph. Making up quotes will not be tolerated, and if you continue to do so, expect to see heavy moderation of your posts.

    The categories in the paper look at recent warming. That is a different question from (warming due to CO2), and if you do not understand the difference then you need to learn about it.

    You are repeating your 1.6% number ignoring the criticism that has show it to be the result of an unreasonable grouping of categories 2-7..

     

  15. From Rob

    "If you had bothered to read the actual paper it's explained why the figures are organized as they are."

    I have read it many times and find that the paler is riddled with statistical biases and that categories 5,6 and 7 are red herrings designed to give a false sense of balance.

    there is no logical reason given why the 3 categories are required other than to give a reason to have categories 5,6 and 7.

    Also I have read many of the category 1 abstracts and find it puzzling how many of them could be considered endorsing category 1.

     

     

     

     

    Response:

    [BL] ...and yet you lump categories 5, 6, and 7 together - along with categories 2 and 3 - when you calculate your irrelevant 1.6% figure. The logic behind those categories is explained in the paper, and has been explained here - you just don't like it.

  16. Albert @915... "Also I have read many of the category 1 abstracts and find it puzzling how many of them could be considered endorsing category 1."

    Please provide an example.

  17. Albert @914... "Once again I ask, why have 3 categories lumped into the "97%" result when only one category saying 'explicit or implicit support that humans contribute to global warming'."

    Think of it in terms of "endorse" vs "minimize" and think of the IPCC position being the subject being either endorsed or minimized.

    Three endorse categories and 3 minimize categories. 

  18. And... "Skeptics believe in the direct effect of CO2 causing an ECS of about 1.2C but reject the positive feedback theory pushing ECS to 3C and beyond."

    Actually, that would be a denial position. You'd have to throw out an enormous body of research to come to such an absurd conclusion.

    The direct effect from CO2 is, as you say, ~1.2°C but you can't just reject physics and say there wouldn't be feedbacks. The feedbacks are very well known. 

  19. And... "Quite commonly I see statements saying that Cooks paper said the "97% of scientists believe that humans are largely (>50%) responsible for global warming" but Cooks paper category 1 clearly and unambiguously states that the figure is 1.6%."

    Here you muck up pretty much everything. The Cook paper is an analysis of research papers, not scientists' opinions. 

    Category 1 explicitly endorses the idea that human's are the primary cause of global warming, and makes quantifications.

    Category 2 explicitly endorses the idea that human's are the primary cause of global warming without making quantifications.

    Category 3 implicitly endorses the idea that human's are the primary cause of global warming.

    Category 5 implicitly minimizes the idea that human's are the primary cause of global warming.

    Category 6 explicitly minimizes the idea that human's are the primary cause of global warming without making quantifications.

    Category 7 explicitly minimizes the idea that human's are the primary cause of global warming, and makes quantifications.

    The level of consensus is the measure of the papers that endorse vs those that minimize.

    It's that simple. A child can understand this.

  20. "The direct effect from CO2 is, as you say, ~1.2°C but you can't just reject physics and say there wouldn't be feedbacks. The feedbacks are very well known"

    Not true. Even a basic knowledge of the complexity of modelling feedback would tll that it is impossible to model or prove.

    it cannot be replicated in the lab or models, and any so called proof can easily be shown to be nit true.

    if you know the basics of feedback theory you would know that the output to any given input has to be known precisely otherwise you cannot determine anything. 

    To give just one example, increased evaporation causes clouds and precipitation and there Are many scientists who believe that the feedback can only be negative or else there would be an exerthermic runaway.

    but if you believe that feedbacks are "well known" pleas provide an exampl that is not ambiguous.

     

    Response:

    [BL] The entire foundation of science is based on models of one sort or another. Your claims of modelling feedbacks being impossible are simply bogus.

    Models should be discussed on the "models are unreliable" myth page.

    Increased evaporation is not a guarantee of increased cloud of precipitation. Your argument is overly simplistic.  Cloud feedback should be discussed on this thread.

    Your  argument that positive feedback leads to a runaway effect is also bogus. Answered on this thread.

     

  21.  "Quite commonly I see statements saying that Cooks paper said the "97% of scientists believe that humans are largely (>50%) responsible for global warming" but Cooks paper category 1 clearly and unambiguously states that the figure is 1.6%."

    please stop throwing in red herrings like "minimise" and tell me why my direct quote is wrong?

    Response:

    [BL] Your quote is not a quote from the category descriptions, and "minimise" is a term used in five of the seven categories in the study, as included in the table I provided in comment 912 (which is directly from the supplemental data).

     

  22. "Three endorse categories and 3 minimize categories."

    and that is the statistical dishonesty of the study because Cook knew that most sceptics are in categories 2 and 3, not categories 6 and 7 so scientific papers expressing no or little belief in AGW would be minuscule.

    Response:

    [BL] Accusations of dishonesty are specifically against the Comments Policy. This applies to accusations against people commenting here, or papers from the scientific literature.

  23. You asked for an example of category one where the abstract doesnt endorse a >50% quantity.

    this is from an article abstract allegedly in category 1 about halons.

    "Substitute fluorocarbons may have direct environmental impact, for example as greenhouse gases, or indirect impacts through the products of their decomposition in the environment. The mechanisms of that atmospheric decomposition are reviewed here and shown to be well established now. The end products are halogen acids and trifluoroacetic acid, all of which pre-exist in the environment in quantities greater than are expected to arise from fluorocarbon use and emissions. Furthermore, the growth in use of fluorocarbon replacements has been shown to be far less than the fall in CFC and Halon production. Hydrochlorofluorocarbons (HCFCs) have replaced less than one third of CFCs and are, themselves, ozone depleting substances that will be phased out under the Montreal Protocol. The growth in hydrofluorocarbons (HFCs) amounts to about 10% of the fall in CFCs. It is likely that the impact of new fluorocarbons on climate change will be a very small fraction of the total impact, which comes mainly from the accumulation of carbon dioxide in the atmosphere."

    pmease tell me how this paper was considered to be category 1?

    in fact, after reading all 64 abstracts i can only find about 45 actually endorsing a >50% anthropogenic effect.

     

    Response:

    [BL] When providing material such as this, you should provide a link to the paper you are referring to. The paper in question is this one.

    Which part of "comes mainly from the accumulation of carbon dioxide in the atmosphere" is hard for you to understand? It explicitly states that CO2 is the main factor - more than 50%.

  24. Albert @921 & other posts ,

    Evidently, you have not read the second part of the Cook 2013 paper, where it clearly shows your "1.6%"  figure is so grossly wrong about the consensus.  So grossly wrong, that it is difficult to believe you are being serious.

    Likewise, you seem suspiciously  uneducated about feedbacks/ runaways.

    Just to throw you a bone : note that the global surface temperature has increased ~1.2 degreesC over about 170 years & an atmospheric CO2 rise of 50%.    Try your math on that.

  25. Albert @920... "...but if you believe that feedbacks are "well known" pleas provide an exampl that is not ambiguous."

    a) You've accepted that the direct effect from doubling CO2 would cause 1.2°C of warming, therefore there would be some loss of ice cover and some increase in water vapor, both producing additional warming.

    b) We have currently raised CO2 levels by about 50% and already seen about 1.2°C of warming in the modern era.

    c) Such low ECS figures would mean the earth's climate should be almost perfectly stable over geologic time (no glacial-interglacial cycles) and we know that's not true.

    d) CO2+feedbacks (~3°C) explain a great many other geologic effects related to temperature including the gradual fall in global temp over the past 60my.

    Dismissing feedbacks is an assertion of blind faith in the face of overwhelming evidence to the contrary. You just have to read the body of research.

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