Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings


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.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Twitter Facebook YouTube Mastodon MeWe

RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
New? Register here
Forgot your password?

Latest Posts

Archives

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

Printable Version  |  Offline PDF Version  |  Link to this page

Argument Feedback

Please use this form to let us know about suggested updates to this rebuttal.

Related Arguments

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

Prev  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  Next

Comments 26 to 50 out of 955:

  1. If science relied on consensus then the Earth would be the center of the universe and you would fall off the edge. Science is not about consensus, opinion is about consensus. A german physisist,Gerhard Gerlich, demonstrated (in a very long and boring paper) how there can be no greenhouse effect. Do we burn him at the stake? I have seen many explanations about how the greenhouse effect works but no proof. Is it real and can it be proven?
  2. #26 here's a good post for you at "A Few Things Ill-Considered." " Definately Not Galileo A common theme among hardcore denialists, after slowly dragging them around to admit there is a consensus, is an appeal to the Galileo syndrome. "Galileo went against the consensus and he was right!" This is a flawed argument in the climate change debate for many reasons, and it is a Guide entry that is missing for the moment. I am only bringing it up now, rather than do a proper entry, because of a discussion paper by Ernst-Georg Beck that was presented on Warwick Hughes' blog (no relation to me... to Glenn Beck? I don't know). It is basically a well dressed version of the "there is no anthropogenic CO2 rise" argument. Eli Rabett took the time to take it apart in a rather thorough and scientific manner, especially given the total lack of a credible conclusion Beck arrives at. You can see the featured graph at Deltoid and read Stoat's dismissive opinion of it here. The irony I want to point out is that Galileo was a forward thinker, reaching into previously untrodden territory. His innovation and imagination helped him see past the prevailing state of human knowledge at the time and go into new ground. What are the denialists doing here? Digging up decades old research with results all over the place, results that lead to all sorts of impossible conclusions and then trying to claim that this is the reality and the new, consistent and refined results are the ones that are wrong. Never mind that this is what progress looks like, this is many minds working to overcome the challenges that caused prior confusion to finally achieve consistent, sensible and reliable data. But what if you don't like what the new data are telling you? Just chuck it and go back to the old stuff! Sorry, that is so not Galileo!" http://illconsidered.blogspot.com/2006/10/definately-not-galileo.html
  3. in response to wonderings #23 relying on the petition project? The term "scientists" is often used in describing signatories. The petition requests signatories list their degree (B.S., M.S., or Ph.D.) and to list their scientific field.[3] The distribution of petitions was relatively uncontrolled: those receiving the petition could check a line that said "send more petition cards for me to distribute". The Petition Project itself used to state: “ Of the 19,700 signatures that the project has received in total so far, 17,800 have been independently verified and the other 1,900 have not yet been independently verified. Of those signers holding the degree of PhD, 95% have now been independently verified. One name that was sent in by enviro pranksters, Geri Halliwell, PhD, has been eliminated. Several names, such as Perry Mason and Robert Byrd are still on the list even though enviro press reports have ridiculed their identity with the names of famous personalities. They are actual signers. Perry Mason, for example, is a PhD Chemist.[2] ” In May 1998 the Seattle Times wrote: “ Several environmental groups questioned dozens of the names: "Perry S. Mason" (the fictitious lawyer?), "Michael J. Fox" (the actor?), "Robert C. Byrd" (the senator?), "John C. Grisham" (the lawyer-author?). And then there's the Spice Girl, a k a. Geraldine Halliwell: The petition listed "Dr. Geri Halliwell" and "Dr. Halliwell." Asked about the pop singer, Robinson said he was duped. The returned petition, one of thousands of mailings he sent out, identified her as having a degree in microbiology and living in Boston. "It's fake," he said.[15] ” In 2005, Scientific American reported: “ Scientific American took a sample of 30 of the 1,400 signatories claiming to hold a Ph.D. in a climate-related science. Of the 26 we were able to identify in various databases, 11 said they still agreed with the petition —- one was an active climate researcher, two others had relevant expertise, and eight signed based on an informal evaluation. Six said they would not sign the petition today, three did not remember any such petition, one had died, and five did not answer repeated messages. Crudely extrapolating, the petition supporters include a core of about 200 climate researchers – a respectable number, though rather a small fraction of the climatological community.[16] ” In a 2005 op-ed in the Hawaii Reporter, Todd Shelly wrote: “ In less than 10 minutes of casual scanning, I found duplicate names (Did two Joe R. Eaglemans and two David Tompkins sign the petition, or were some individuals counted twice?), single names without even an initial (Biolchini), corporate names (Graybeal & Sayre, Inc. How does a business sign a petition?), and an apparently phony single name (Redwine, Ph.D.). These examples underscore a major weakness of the list: there is no way to check the authenticity of the names. Names are given, but no identifying information (e.g., institutional affiliation) is provided. Why the lack of transparency?[17]" wikipedia.com and........... "Oregon Institute of Science and Medicine The Marshall Institute co-sponsored with the OISM a deceptive campaign -- known as the Petition Project -- to undermine and discredit the scientific authority of the IPCC and to oppose the Kyoto Protocol. Early in the spring of 1998, thousands of scientists around the country received a mass mailing urging them to sign a petition calling on the government to reject the Kyoto Protocol. The petition was accompanied by other pieces including an article formatted to mimic the journal of the National Academy of Sciences. Subsequent research revealed that the article had not been peer-reviewed, nor published, nor even accepted for publication in that journal and the Academy released a strong statement disclaiming any connection to this effort and reaffirming the reality of climate change. The Petition resurfaced in 2001." http://www.ucsusa.org/global_warming/science/skeptic-organizations.html
  4. and on the Heidelberg Appeal.............. "Parts of the Heidelberg Appeal do endorse environmental concerns, such as a sentence that states, "We fully subscribe to the objectives of a scientific ecology for a universe whose resources must be taken stock of, monitored and preserved." Its 72 Nobel laureates include 49 who also signed the "World Scientists' Warning to Humanity," which was circulated that same year by the Union of Concerned Scientists (UCS) and attracted the majority of the world's living Nobel laureates in science along with some 1,700 other leading scientists. In contrast with the vagueness of the Heidelberg Appeal, the "World Scientists' Warning" is a very explicit environmental manifesto, stating that "human beings and the natural world are on a collision course" and citing ozone depletion, global climate change, air pollution, groundwater depletion, deforestation, overfishing, and species extinction among the trends that threaten to "so alter the living world that it will be unable to sustain life in the manner that we know." Moreover the Heidelberg Appeal has been, if not specifically misrepresented, at least broadly interpreted out of context, for example, by The National Center for Public Policy which asserts "The appeal warns industrialized nations that no compelling scientific consensus exists to justify mandatory greenhouse gas emissions cuts."" http://en.wikipedia.org/wiki/Heidelberg_Appeal
  5. Yup, clearly ignoring the entire point. You continue to waste my time here. If you can't answer the main points and instead must repeatedly resort to nibbling on the fringes of the petition project it appears you are merely trying to obfuscate the issue. I am trying to learn things here other than your bias. You seriously are proud that there was 1 fake signature out of 20,000? Even if it was 2000 fakes you would have lost that argument wouldn't you? Please,you've proven my point to any unbiased reader.
  6. if it's such a waste of your time, stay the heck away. You seriously don't understand that any "fake" signatures, and there were many on both, not to mention the fraudulant article to support the "petition project", you really mean to say that you can't grasp that that in and of itself shows the desperate need to dupe the public with policy driven pseudo-science? you're point is on your head.
  7. and were do you get "1"? but please, wondering, rephrase your point for me. perhaps I have misunderstood?
  8. WA, I don't understand why you would even pay attention to the "my list is bigger than yours" type of attitude, which is obviously utter nonsense. Why are you trying to defend that so-called "petition project?" What does that have to do with science and evidence? Disputing that there is a consensus among climate scientists is downright futile. All sources of information arguing that point are non scientific (Heartland, Cato, Inhofe's office, CO2 science and all that crap). Real scientific organizations (AAAS, AGU, etc) endorse the AGW hypothesis, which is by itself an interesting fact. I find it really funny that "skeptics" both dispute the existence of a consensus and also argue that consensus is meaningless anyway, as Quietman does with a mightily inappropriate comparison. As for Quietman post about Gerlich's pathetic load of dung, Rabett Run has more on that than anyone really needs to know. And to answer his question, there is no doubt about the radiative properties of CO2 and the reality of the GH effect. It can be precisely measured in the lab, and if there was no GH effect, this planet would be an ice covered rock. The Gerlich paper is also funny in the sense that it denies the very existence of a GH effect at all but, later, the authors questioned about Venus go on explaining Venus' temps by GH effect from other sources than CO2. It's perfectly grotesque, a fine example of the worst BS that denialism can produce. The quality of skepticism here is on the way down if that's the kind of stuff we're going to talk about. Well, BTN had already set the bar so far down that we might have a margin anyway, but still. This my thought of the day to you, Quietman, and others. You can not apply extreme scrutiny to the CO2 hypothesis and lower scrutiny to alternate explanations. I know that it makes for a lot more work but that's the only way. If you apply the same extreme scrutiny to these other alternate explanations, what is left of them? Have you even tried (sincerely)? If not, you can not call yourself a skeptic in the true sense of the word. In my experience, if you try to take apart these alternate theories with any eagerness comparable to what "skeptics" use against the CO2 hypothesis, there is nothing left, zilch, nada. That's one reason why I'm skeptical about climate skepticism.
  9. WA: "The claim that there is some vast number of scientists that constitute a consensus and that agree with catastrophic warming is not only not science it isn't even correct." Here is a strawman so big, it's more akin to the Chinese straw dogs. Let's merrily burn it. Indeed, it's not correct at all. The SCIENTIFIC consensus is that there is warming, happening quite fast, and that the massive CO2 release from the burning of fossil fuels is a major contributor to it. That is the real consensus.
  10. paledriver, Read from the 3rd paragraph on of my post 16. That was my point. I do indeed think it is clear that the public is being duped. I think it is deliberate and I think the AGW alarmists are the ones doing it. The "many fake signatures" is both clearly incorrect and irrelevent. By your own references over 90% were verified. Phillippe I don't agree with your way of stating the consensus though It isn't far enough off to argue. On your double standard point though, Phillippe, that is exactly the contention I have been making from the other side of the issue for a long time so it is kind of funny. The correct hypothesis has to defeat all the others. It has to pass the experimental test and make predictions that other hypothesis don't. Being experimentally supported is the beginning of this; that isn't enough to prove it, but at this point we haven't even got that. Being only not much worse than the other explanations is not enough. Holding the accepted theory to the highest standard is what a scientist is supposed to do. It only takes one thing to prove it wrong. The perhaps painful truth is CO2 has not been a major cause of climate change in the past, despite levels many times the current level. In order to believe it is about to cause huge consequences today when it never did in the past you need some pretty convincing proof or some new physical reality. John I am pretty impressed with how current you keep your articles references.
  11. "The perhaps painful truth is CO2 has not been a major cause of climate change in the past" That may be because there has not been a release of CO2 on the scale we experienced these last 150 years during the 600k years of very stable climate the planet has been through. If you try to go farther in time, there is too much uncertainty to do informative comparisons. There is nothing to prove that a massive injection of CO2 in an otherwise stable climate can not have serious consequences. And, by the way, spare me the exaggerations that have nothing to do with what the research actually shows and suggest is possible. I do not pay more attention to exaggerated claims from advocay groups, whether they're from one side of the spectrum or the other. And I also maintain that, if you are a true skeptic with physics background, you should be screaming bloody murder to the flat-earthers like Gerlich. If not, then you're applying a double standard far worse than anything you claim is practiced in the scientific peer-reviewed litterature.
  12. Re 23 Wondering Aloud 'Not all that glisters is gold' And The Oregon Petition of Science and Medicine 'Petition Project' Review, now updated with a change in authors was neither peer-reviewed (despite explicit claims)), nor science - it was deceptive pseudo-science, deliberately formatted to appear as if it were a NAS publication (and therefore peer-reviewed). For an excellent insight into the Oregon Petition Document, see: http://tinyurl.com/nt38z This is from a Professor who frankly admits that he was nearly fooled by it. Enough people were fooled that the National Academy was inundated with calls asking if it was their new position and had to issue a news release. Quote ''The Council of the National Academy of Sciences (NAS) is concerned about the confusion cause by a petition being circulated via a letter from a former president of this Academy. This petition criticizes the science underlying the Kyoto treaty on carbon dioxide emissions (the Kyoto Protocol to the Framework Convention on Climate Change), and it asks scientists to recommend rejection of this treaty by the U.S. Senate. The petition was mailed with an op-ed article from The Wall Street Journal and a manuscript in a format that is nearly identical to that of scientific articles published in the Proceedings of the National Academy of Sciences. The NAS Council would like to make it clear that this petition has nothing to do with the National Academy of Sciences and that the manuscript was not published in the Proceedings of the National Academy of Sciences or in any other peer-reviewed journal. The petition does not reflect the conclusions of expert reports of the Academy.'' End quote http://tinyurl.com/38nqdj Note: Seitz, Baliunas & Soon are all associated with the ExxonMobil funded George C Marshall Institute! Seitz was a solid-state Physicist. Baliunas & Soon are Astrophysicists. Arthur Robinson and his son Zachary are Chemists. Note that none of the authors of this purportedly climatological paper are climatologists!
  13. The updated version of this OISM 'review' was published in that well known organ of climate research - The Journal of American Physicians and Surgeons (2007). Little wonder that it survived peer review. Apparently the previous 1998 version was later published in Climate Research - A Journal that has had serious problems with its criticised peer-review process, notably under the editorship of Chris de Freitas, under whom numerous editors resigned in protest. I don't know when the 1998 version was published, or whether the Editor was de Freitas. But there seem to have been some pretty suspect papers published in CR.
  14. Philippe (36) said: "That may be because there has not been a release of CO2 on the scale we experienced these last 150 years during the 600k years of very stable climate the planet has been through." Hold on, did anyone else notice that? 600k years of very stable climate? The last 600k years has been a torrent of climatic change. So if by "stable" you mean "always changing between extremes," then yes, you are correct. Beyond that, the Earth's climate has never really been stable. I just had to point out that ridiculous comment.
  15. Robert, these extremes are very well constrained compared to numerous changes that happened before that period. It is fair to say that the climate of the past 600k years has been quite stable compared to the climate of times before that, because those "extremes" remain within a certain range. Even the periodicity of the changes remains overall nicely consistent. So my comment is far from being ridiculous. This page gives a quick glance at very long term variability: http://www.scotese.com/climate.htm I have ran many times into the argument that climate has changed to extremes in the past and they always call on paleoclimate examples from way before the ice core records, especially hot house periods of the mesozoic times, which are of little relevance to our situation. Besides, it is interesting to note that the 2 largest mass extinctions of the geological record happened in hot times (P/T and Cretaceous). It is also interesting to look at how CO2 has changed during these 600k years compared to what has happened in the (very) recent past. There is no precedent in the ice core record to such an injection of CO2. Nothing even remotely comparable to it. See this link, slide number 8. http://ec.europa.eu/research/environment/pdf/descriptions/raynaud_ipy_bxl07.pdf
  16. Thanks for the response. You say: "Robert, these extremes are very well constrained compared to numerous changes that happened before that period. It is fair to say that the climate of the past 600k years has been quite stable compared to the climate of times before that, because those "extremes" remain within a certain range. Even the periodicity of the changes remains overall nicely consistent. So my comment is far from being ridiculous." and then you say: "I have ran many times into the argument that climate has changed to extremes in the past and they always call on paleoclimate examples from way before the ice core records, especially hot house periods of the mesozoic times, which are of little relevance to our situation." This seems slightly peculiar--you use that very comparison in your first paragraph. Regardless, the last 600,000 only appears stable when compared to the vastly different time scale of the previous 600myr (such a comparison is not useful). Essentially your argument boils down to the "the last 600k years have been stable in that they are consistent in their extremes and periodicity." The belief in constant change as "very stable climate" seems misplaced. Then you say: "Besides, it is interesting to note that the 2 largest mass extinctions of the geological record happened in hot times (P/T and Cretaceous)." They did occur in "hot times," but the mechanism behind these extinctions is considered to be volcanism and/or meteor impact-- blocking sunlight and preventing photosynthesis. On the other hand, the Ordovician-Silurian extinction (3rd largest) occurred during the transition to one of the largest Ice Ages in the past 600myr. Anyhow, this seems irrelevant to my response (39) above. Your last paragraph also seems irrelevant--I don't disagree that CO2 is higher now than any time in the last 600kyr. -Robert
  17. Change alone does not make unstability. Perhaps a comparison with weather would be useful. The weather changes continuously along the year, yet we deal with it just fine so long as nothing happens like 4 months without rain or freezing in june. The examples of hot house as in the mesozoic times are commonly used by advocates who argue that because it has been very hot before, it's OK to go that route again now. The fact that the world and the biosphere were vastly different in these times is what makes that argument irrelevant, not the climatological elements themselves. Those advocates often argue that warmer is better, yet mass exctinctions have happened during these periods, indicating that a hot house does not guarantee against them. The cause of the Permian extinction is unknown. I don't know any that has been established for the Ordovician. So the volcanic/collision explanation for mass extinction applies with any level of certainty to the Cretaceous only.
  18. Philippe said: "Change alone does not make unstability. Perhaps a comparison with weather would be useful. The weather changes continuously along the year, yet we deal with it just fine so long as nothing happens like 4 months without rain or freezing in june." You have invoked two comparisons which are irrelevant: Weather and climate more than 600kya. And your last sentence seems odd--based upon other interglacials, we have been in late november for the last 2000 years and the first frost still hasn't come. Then Philippe said: "The examples of hot house as in the mesozoic times are commonly used by advocates who argue that because it has been very hot before, it's OK to go that route again now. The fact that the world and the biosphere were vastly different in these times is what makes that argument irrelevant, not the climatological elements themselves. Those advocates often argue that warmer is better, yet mass exctinctions have happened during these periods, indicating that a hot house does not guarantee against them." I don't know who these "advocates" are but this does not seem to be in either of my responses. "The cause of the Permian extinction is unknown. I don't know any that has been established for the Ordovician. So the volcanic/collision explanation for mass extinction applies with any level of certainty to the Cretaceous only." The cause for an ancient extinction is never "known." It has been speculated that the Permian extinction was caused by a similar event to the one that caused the Cretaceous--volcanism and/or meteor impact. The Ordovician-Silurian extinction occurred at the transition to one of the largest Ice Ages in the last 600myr. So while he cause is not "known," the current running theory speculates that the cause is the somewhat rapid decrease in temperatures.
  19. When you compare the last 600kyr to the previous 600myr, of course the climate looks "very stable," but that is not a meaningful comparison--it's useless. Not only is the time scale vastly different, but the mechanism for change is as well (also, time periods before the ice core record are far less certain). No great departure from extremes does not necessarily equate to "very stable climate."
  20. The weather comparison is not useless or irrelevant. Events like freezing in june or 4 months without rain are elements of instability, if they turn into a trend. Just like being in late november and still waiting for a frost to come, if it happens more and more regularly (as it has). About climate, a warming like the one seen lately, while temps should be stable in our kind of time scale, is an element of instability. A massive injection in the atmosphere of a gas ike CO2 (whose physical properties are known) is also an element of instability.
  21. My comparison using November and late frost was meant to imply that this interglacial has gone on several thousand years too long, with respect to previous interglacials. You say: "About climate, a warming like the one seen lately, while temps should be stable in our kind of time scale, is an element of instability." If the recent warming is an element of instability, then you have just contradicted your previous assertion that we have had 600kyr of very stable climate, because events similar to the recent warming have occurred a multitude of times in the last half a million years. The recent warming is hardly unprecedented.
  22. "The recent warming is hardly unprecedented." Even in periods of end interglacial times, when temps would be expected to slowly cooling down, as you mentioned? Even on that kind of time scale, a blink of an eye really? OK, but can you substantiate with references?
  23. Philippe wrote: "Even in periods of end interglacial times, when temps would be expected to slowly cooling down, as you mentioned?" Is it a "period of end interglacial time"? Well it depends on what you think causes the glacial periods--if the mechanism isn't there, then it isn't going to happen. If you believe the Milankovitch cycles are what initiates the glacial/interglacial, then we are still a ways from another glacial period. So it is not inconceivable that the planet would experience a warming at this time. Then he wrote: "Even on that kind of time scale, a blink of an eye really? OK, but can you substantiate with references?" If you want to take issue with the idea that the planet has had warming similar to the recent warming on both the time scale and in magnitude, be my guest. It would be a losing battle. As for references, all one has to do is a little searching--this interglacial, the last glacial, the last interglacial, etc. It won't be too hard to find warming of this magnitude in this time scale.
  24. All of you do realize of course that there is a very basic premise involved: If there was a consensus, there would be very little dissent. Given the extremely large amount of dissent, we must assume one of two things: 1) there is no consensus or 2) the consensus is not what the IPCC claims it to be.
  25. The so-called "large amount of dissent" is just a small group of people making a lot of noise again and again. Remember the claim that there were 19,000 scientists disputing global warming? During the New York denialist conference ("2008 International Conference on Climate Change"), it turned out there were only _19_ scientists. Looks like the number 19,000 is off by a factor of 1,000. As an added bogus, the logo for the denialist conference was a loudspeaker. -- bi, http://frankbi.wordpress.com/

Prev  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  Next

Post a Comment

Political, off-topic or ad hominem comments will be deleted. Comments Policy...

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.

Link to this page



The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us