Climate Science Glossary

Term Lookup

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


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


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

Bluesky Facebook LinkedIn Mastodon MeWe

Twitter YouTube 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...

New? Register here
Forgot your password?

Latest Posts


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 1956 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 1, 2024: Corrected a typo in the publication year for Plass (1956) in the at-a-glance section.

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

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.


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


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


Prev  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  

Comments 801 to 802 out of 802:

  1. I have a few quotes from the article to comment on.

    "Science achieves a consensus when scientists stop arguing." But the arguing continues. When it stops you have orthodoxy and heretics.

    "But the testing period must come to an end." I suspect a lot of testing and improved model building is needed which should keep the testing going.

    "That’s why those who oppose taking action to curb climate change have engaged in a misinformation campaign to deny the existence of the expert consensus." Hey, that's quite a claim. Maybe they believe what they say?

    I don't have a fixed position yet on global warming. I have been looking at some of the scientists who aren't part of the consensus. I hope it's not considered dangerous to look at their views- do we get excommunicated for doing so? Whenever I mention any of the non conforming in other forums- the biggest comeback is that they're all on the take from the fossil fuel industries or they're just stupid. I don't really care who pays them and I'd hardly consider anyone with a Phd as stupid.

    Aside from the many non conforming scientists- I've found one interesting guy, Alex Epstein, a philospher by training who has published his book on the subject, "The Moral Case for Fossil Fuels". I watched him debate Bill McKibben back in 2014. It's on YouTube. I think he held his own in that debate. I don't think it's fair to instantly dismiss such thinkers. He admits upfront that he's had connections with that industry- so no need to point that out. He has a very interesting perspective- worth looking at, even by those convinced of the existential threat of climate change. It doesn't hurt to see what the opposition is up to. I found his book so interesting I'd like to get a discussion going on this forum, if that's possible- but it probably isn't.


    [PS] This thread is for discussion of consensus studies. Please take any discussion of a moral case for fossil fuels to the weekly roundup thread.

  2. JoeZ @801 ,

    Yes, there are "scientists who aren't part of the consensus" ~ but there are hardly any climate scientists who would fit in that category.   That is why the Consensus is only 99+% , not absolutely 100%  .   Far worse for your unstated position, JoeZ, those very few scientists had all produced hypotheses which have been thoroughly disproven (see Svensmark, Lindzen) . . . and worse again, they contain a high percentage of religious crackpots who are not strictly scientific in their mode of thinking.

    Are they "stupid"?   Well, stupid is a rather elastic term.   I myself know a fellow who has a PhD and spent decades in scientific research [but not in climate-related matters] and yet he is a member of the local Flat Earth Society.  Unsurprisingly, he is also in denial about global warming.

    Is he stupid?  He is pleasant, sociable, and intelligent ~ but that doesn't stop him from being quite wrong about important issues.   Just like Lindzen & his comrades who are over-influenced by irrational religious beliefs or extremist political beliefs.   They put their ego ahead of scientific thinking.

    Also rather like your Mr Alex Epstein (who is an author, not a philosopher) who chooses to write a book, not submitting his ideas to the point-by-point criticism which would occur in the process of peer-review in a scientific paper.   JoeZ, it is easy to write a book and have your unbalanced rhetoric sweep your ill-informed readers into a state of intellectual submission & adulation . . . just as it is easy to make a "documentary" film about a subject [ here, "The Great Global Warming Swindle" comes to mind ] where severely-doctored graphs and fallacious logic are employed.  The general reading/viewing public are not to know how fake it all is, unless they take the trouble to apply critical thinking and to educate themselves on the basics of the issue.

    In the end, JoeZ , it all comes down to evidence.   And evidence is the thing lacking in the positions taken by those "non-consensus" scientists.  The climate consensus exists because of the climate evidence.   

  3. Please forgive me if this sub-issue has been covered already... I read the first few pages where it was being discussed without resolution, and in the last few pages it is not mentioned.

    But what exactly is "the consensus"?  That the AGW hypothesis is true and it will have increasing implications on global weather patterns?  Or that there it is a catastrophic situation and human must immediately and completely restructure our social and economic systems if the species is to survive?

    In some of the arguments I've read so far, the believers seemed to be defending the former, and the skeptics were challenging the latter.

    In the previous post (sorry, I don't know how to do that thing that references it yet) Eclectic seemed to criticize anti-AGW propaganda films masquerading as information, yet the same critiques could be made of the propaganda films from the other side, like Gore and DiCapprio's popular films, full of dramatic music and hyperbole.

    I find it surprising that any intelligent and well meaning people still take the position that AGW is a complete hoax, but there is certainly a huge space for reasonable debate on the costs and risks of various strategies to reduce it or mitigate the damage.

    Furthermore, I suggest it is the fact that so many people are taking a rather extreme alarmist position (if we don't do something radical in the next xyz years, we're doomed!) that make many other people rebel, and say obviously that's ridiculous, I think you're making the whole thing up.

    It really is a thorny problem, considering the vast number of people now coming out of poverty, and having access to electricity and other technologies for the first time.  And I see no recognition of the logarithmic nature of the greenhouse effect, which makes the political problems almost insurmountable.

  4. Cstrouss;

    There are different measures of the consensus but Cook et al used the IPCC reports.  Since these are scientific reports that have been accepted line by line by all nations in the world they are a god pace to start.  Many people feel that they are too conservative but deniers say scientists are all alarmists.

    The most recent IPCC report says that we have only 12 years from January 1, 2018 to reduce emissions to zero if we want to limit waring to 1.5C.  For that we have a 66% chance of keeping warming less than 1.5C.  Already we have severe heat waves: over 75,000 hospitalized in Japan alone.  Half of the Great Barrior reef is dead.  Unprecedented floods in the US this year have seriously lowered food production.  If we succeed, little action has been taken as yet, we still have a 33% chance of greater than 1.5C.  

    10 years ago I wondered if I would see the effects of climate change in my lifetime (I am currently 60).  Now we see terrible floods and heatwaves.  Houses and towns are flooded by record rainfall and affected by sea level rise.  Many migrants coming to the US are fleeing AGW caused drought. Gore underestimated the problems in his movie.  The changes currently at 1C are dramatic.  How bad do they have to get before you become concerned?

    Watch some of Greta Thunbergs talks on line.  She speaks clearly about the science and does not pull punches.  As she says, this is an emergency and shoud be treated as such.

    Your suggestion that there are two sides is inaccurate.  One side is what people who have studied climate for 100 years have learned and the other is what fossil fuel executives tell you.  One side only cares about what will happen to their chilldren and the other only cares about their bonus this quarter.  Who do you trust?

  5. Michael:  Seriously, you're pointing to a 16 year old Swedish actress as a source of information?  Why not that kid from Titanic?  He made a movie about climate, too.

    I've actually answered my own question now, as I'm learning to use this site, and you got the consensus very wrong. The "advanced" tab gives the actual proposition: "Surveys of the peer-reviewed scientific literature and the opinions of experts consistently show a 97–98% consensus that humans are causing global warming." 

    Most of the IPCC signatories don't even agree with the entire report.  So the IPCC report is not the consensus.

    Also, it's wrong to suggest that everyone who isn't a full bore alarmist is an oil industry shill. If it's all about bias, let's not forget that Gore became extremely wealthy with his "post-carbon" portfolio, but his profit motive does not invalidate his arguments. 

    As far as an indisputable expert who I think is reasonably unbiased and presents a non-alarmist position, my first thought would be to point to Cliff Mass at University of Washington.

     So then there are deeper questions... What can realistically be done to slow or mitigate AGW, given the global political implications, the millions of people rising out of poverty, and the logarithmic nature of the greenhouse effect.. but that is not the topic for this thread.

    The consensus being discussed in this thread is clear... AGW exists, which is a rather trivial conclusion... so I will search elsewhere on the site to see if anyone is diving into the more complicated and practical issues.

  6. Cstrouss , you give the strong impression you are not really interested in the climate science or the scientific consensus.

    Are you interested in the consensus of the world's leading economists — which is that the cost of not  taking action against AGW is far, far higher than the cost of phasing-in "renewables" to replace fossil-fuels.

    It is grossly alarmist to represent that "renewables" change-over as the immediate and complete restructure of our social and economic systems . . . don't you think ?

  7. Eclectic, I'm 100% in favor of conservation and a change-over to renewables as they become more economically feasible... more importantly I advocate serious investment in research to hasten that process.  That is not an issue.

    The issue is radical transformations that have been proposed like "the Green New Deal," which would have a devastating effect on low income people like myself, who will not be able to afford used electric vehicles for another decade or two.  And it would have ZERO direct affect on AGW, given the logarithmic nature of the greenhouse affect and the number of people receiving electrification for the first time.

    So I think it is important to view it as a long-term issue, that will necessarily involve innovation and mitigation of climate changes that cannot be avoided.

    But as I said, that is all off-topic for this thread.  This is about the consensus that AGW exists, not about the magnitude or solutions.

  8. Cstrouss , 

    the scientific consensus is about the science, not the political response required.

    The so-called Green New Deal which might "radically transform" the U.S. economy (in less than 12 years?!?! ) . . . is mere fanciful hyperbole.   Nor would it directly involve the other 95% of the world's population.

    Cstrouss, you are using the GND as a strawman (straw-woman??).   Please take a sensible look at the scientific facts — and the facts indicate that it would be foolish to delay the conversion to a renewables-based economy.  Is there any other conclusion to be drawn from the consensus?

    Cstrouss, if you have a point to make then please make it clearly and simply (and on another, more appropriate thread).

    No need for straw.

  9. cstrouss...

    "That the AGW hypothesis is true and it will have increasing implications on global weather patterns? Or that there it is a catastrophic situation and human must immediately and completely restructure our social and economic systems if the species is to survive?

    Why is this an either/or question? Can they not both be true?

    Think of climate change impacts as a sliding scale that vary based on our total emissions. Within a reasonable range of uncertainty, probably the best understood elements of AGW are the basics of radiative forcing and the response in global mean temperature. The concensus is that we'll likely see about 2.8°C of warming for each doubling of CO2 over preindustrial levels. I think almost every scientist working in the field would agree with that statement.

    We also know for certain, the more we push the system, the more damage we're ultimately going to see. Again, that's not a controversial statement for scientists.

    What you're doing, though, is running off into hyperbole. I don't think many scientists would agree that we must "...immediately and completely restructure our social and economic systems if the species is to survive." Our species is likely to survive whatever happens. We're extraordinarily adaptable. But, most of the natural world that we rely on to sustain 7+ billion people on the planet is not nearly as adaptable as we are.

    Therein lay the problem. Yes, if we continue to burn everything we can get dig out of the earth, most scientists will likely agree that would probably mean a total collapse of modern civilization. Lots of death, destruction and suffering.

    Can we avoid that? Yes, of course. We are going to see significant challenges and costs due to our emissions so far. We are already seeing very good signs of progress with the cost of wind and solar continuing to fall. But there are so many more challenges we're going to see.

    Nothing I'm saying here is controversial, and I believe this would all fall within the definition of the "scientific consensus on AGW." 

    Here's what should give you the most concern about all this: thermal inertia.

    I hope you agree that we are now seeing many of the impacts of climate change starting to emerge. Melting ice sheets, extreme weather events, heat waves, etc. Now, consider that there is a 30 year lag in the climate system since most of the heat goes into the world's oceans. That heat takes time to come into equilibrium with the land, ice and atmosphere. Thus the impacts we're seeing today are the result of where CO2 levels were some 30 years ago. 

    If we were to stop all carbon emissions tomorrow the planet would continue to warm through the middle of this century. If we're seeing impacts already you can bet your bottom dollar they're going to start getting a lot worse over the coming three decades. Best case scenario says we'll be able to bring emissions to zero by ~2050. That means continued warming through 2080 at a minimum.

    Also consider that, in the past at 450ppmv CO2 levels, there were no ice sheets on this planet. The planet was too warm to sustain them. It'll take another 1000 years to melt them entirely, but we're talking about sea levels rising to up to 70m over the coming centuries. That's a completely different planet than we currently live on. No Florida at all. It's gone. LA, SF, NYC, Tokyo, and 100's of other cities. All under water. 

    It's not the end of our species but replacing entire cities ain't gonna be cheap. The better investment is to reduce our carbon emissions as quickly as we can and keep CO2 levels as low as we possibly can. That's an enormous task. It's one that needs to happen fast.

    Again, none of this is controversial. Gore, DiCaprio and Thunberg are not scientists but they are doing their level best to help convey to the world what is overwhelmingly agreed in the scientific community.

  10. You know, I bet you might find this short video compelling. 

    Stephen Schneider montage.

  11. Cstrouss,

    It is too bad that you canot afford future electric cars.  According to this white paper put out by BNP Paribas (the eighth largest bank in the world) between 2020 and 2022 electric cars using renewable energy (wind and solar) will be by far the cheapest cars.  You will be spending more to pollute the air for the rest of us.

    You show your true colors when you call Greta Thunberg an actor.

    I can see where you are going.  Unfortunately, I do not have time for you today.  Good luck.

  12. This is a genuinely bizarre statement: "Most of the IPCC signatories don't even agree with the entire report. So the IPCC report is not the consensus."

    I'm very curious where you picked that up. 

  13. Eclectic wrote:

    >>> the scientific consensus is about the science, not the political response required. <<<

    Yes, and I'm trying to keep that distinction clear. The consensus is that there is a problem. And given the inherently geo-political nature of the problem, I have not yet seen a workable solution proposed, let alone any wide consensus on it. In fact I very rarely see mention of the logarithmic nature of the problem, which is what makes it so intractable.

    Is there another forum where those issues are discussed?

    >>> ... the facts indicate that it would be foolish to delay the conversion to a renewables-based economy. Is there any other conclusion to be drawn from the consensus? <<<

    Well again we have to be clear on what the consensus is. This thread is about documenting and quanitfying the consensus that AGW exists, not about its scope or the urgency of solutions. Some have asserted in the last few comments that the consensus is that the latest IPCC report is correct, which is a step in that direction, but there is no evidence presented for that or how wide the consensus may be.

    >>> Cstrouss, if you have a point to make then please make it clearly and simply (and on another, more appropriate thread). <<<

    I agree, my question has been answered... the consensus is that AGW exists, as indicated in the formal proposition in the header, and consistent with my other reading. I'm not the one continuing the discussion into separate issues, like the severity, urgency, and strategies.

    I wrote:

    "...That the AGW hypothesis is true... Or that there it is a catastrophic situation and humans must immediately... <<<

    Rob Honeycutt responded:

    >>> Why is this an either/or question? Can they not both be true? <<<

    They can both be true, but are they both the consensus? If the consensus includes the latter, could you present evidence of that?

    >>> What you're doing, though, is running off into hyperbole... <<<

    Yes, guilty, that one thing was a bit overboard. My point is that what is being proposed are some very radical solutions with no real return, unless you go with the idea that if the USA spends a great deal of money, the rest of the world, including much poorer and rapidly developing regions will follow. (I heard Sanders say something along those lines the other day.)

    But of course that gets far outside the domain of climate science. It is a matter for political science and psychology, and necessarily involves a tremendous amount of speculation.

    >>> Therein lay the problem. Yes, if we continue to burn everything we can get dig out of the earth, most scientists will likely agree that would probably mean a total collapse of modern civilization. Lots of death, destruction and suffering. <<<

    Now who is engaging in hyperbole? Are we digging everything we can out of the earth? And if so, who is proposing that we continue doing that? Is the collapse of civilization with continued CO2 emissions also part of the consensus? Documentation?

    >>> Can we avoid that? Yes, of course. We are going to see significant challenges and costs due to our emissions so far. We are already seeing very good signs of progress with the cost of wind and solar continuing to fall. But there are so many more challenges we're going to see. <<<

    Again, we agree on that. I think it is great for wealthy people in wealthy nations to voluntarily adopt more expensive alternative forms of energy. In fact all of my super affluent friends are already making great strides, except for their regular jet travel.

    And no doubt progress is being made on the technology, and the small-scale interim deployments have been helping to refine the tech.  I have two good friends who have been working as engineers on photovoltaic systems for at least 25 years. They tell me we can expect a lot of changes in the next 20 years.

    The issue is what to do with the less affluent population. Will I be left behind? And even though I'm in the lower end of income in the USA, I'm still in the upper end in the world. I can barely afford one tank of gas per month in my 20 year old compact car now.

    I know that places where large numbers of people are rising out of dire poverty for the first time, like areas in Asia and Africa, are on the ragged edge of affording energy in the first place. Even when alternatives are CLOSE to fossil fuel costs, that is a luxury they will not be able to afford. I'm sure you're aware of studies that show people will only sacrifice to improve their natural environment after a certain level of affluence is attained.

    I'm sure you'll agree that it will not address the problem if the richest 20% reduce their emissions by 50%, when a billion or two people are increasing their consumption a great deal from virtually zero. So any attempts to force those nations and people to reduce (instead of increase) their use of fossil fuels will only happen if those rich nations are willing to foot the bill for alternative electrification. Certainly it is technically feasible, and would make a lot of sense, since distributed solar is a more efficient way of building rural electrical systems than power plants and long wired grids, but I have not heard this level of financial assistance being proposed.

    >>> Nothing I'm saying here is controversial, and I believe this would all fall within the definition of the "scientific consensus on AGW." <<<

    Well now we're getting back on topic. Is that your opinion, or do you have studies to back it? This thread refers to several studies that document a strong consensus that AGW EXISTS. I have not scoured the whole thing, but I have not seen any evidence to quantify the consensus for stronger propositions. Certainly that would have to be considerably less than the approximately 97% which apparently accept the minimalist proposition.

    >>> Here's what should give you the most concern about all this: thermal inertia.... Best case scenario says we'll be able to bring emissions to zero by ~2050. That means continued warming through 2080 at a minimum. <<<

    Yes yes, I understand that. But I have not heard any suggestions on how global emissions could realistically go to zero by 2050.

    michael sweet wrote:

    >> It is too bad that you canot afford future electric cars. According to this white paper put out by BNP Paribas (the eighth largest bank in the world) between 2020 and 2022 electric cars using renewable energy (wind and solar) will be by far the cheapest cars. You will be spending more to pollute the air for the rest of us. <<<

    Wow, I'm really sorry I'm so poor I have to inconvenience rich people who can afford new cars. Thank you for the compassion and understanding for those less fortunate than yourself. And by the way, any solutions that do not address the issues of the less affluent masses will never happen.

    By the time a 2020 electric car is affordable for people like me who need simple, reliable 20 year old cars, I'll be dead. Also, given battery life issues, it isn't clear whether any 2020 models will still be serviceable when they are 20 years old.

    >>>... You show your true colors when you call Greta Thunberg an actor. <<<

    I tried to research her. Certainly her parents and grandfather are in show biz. I couldn't find much else about her, but I'm going to assume she is not a published climate scientist who did original research. She seems to be repeating what others have told her... in other words, a celebrity spokesperson, and not a source.

    Rob Honeycutt wrote:

    >>> This is a genuinely bizarre statement: "Most of the IPCC signatories don't even agree with the entire report. So the IPCC report is not the consensus."... I'm very curious where you picked that up. <<<

    Yeah, me too... I can't find it again now. I have seen interviews with signatories who were critical of how the process was segmented, and who very displeased with how the politicians tacked on a "summary for policymakers" that did not follow from the scientific parts of the report.

    And I've read letters from other sigantories who have clarified that they do not agree with all of the conclusions, which of course is inevitable, as you won't ever get 2500 people to agree with everything in a long document, or even 97% of them.

    But since I can't find my references at the moment, I'll retract it unless and until I can document it. Meanwhile, I think the burden of proof is on those who assert that the IPCC report does represent a community-wide consensus.

  14. Cstrouss ,

    I also have a 20-year-old car.  That's not a rare state of affairs.

    But I do not have the anger issues which you are displaying.   If you wish to go further in discussing the range of topics you are raising, then please [in accordance with SkS site posting rules] take each separate aspect to its own appropriate thread.

    The posting rules exist precisely for this purpose — to prevent every thread becoming a chaos of churning unresolving random shoot-em-ups by those without the mental discipline to clearly think through the individual aspects (which make up the "whole").

    But you may find that the Moderators give short shrift to those whose "shotgun pellets" land in a handful of threads simultaneously.   So please draw up your own mental list of matters which trouble or anger you — and select the most important one, and post that.   Once that one has had a reasonable airing [resolved to general satisfaction; or put aside as "agreeing to differ"] then move on to your "second priority" aspect . . . and so on.

    Clear thinking, without the obfuscations & rhetorical deceits & uninsightful semantic confusions . . . is more likely to bring you the satisfaction you are requiring.   Yes, there is the risk that you might find you have to change your current "beliefs" — but I would like to imagine you have the courage to put your intellect ahead of your ego.

    "Motivated Reasoning" is a danger to all of us . . . don't you think?

  15. cstrouss @813,

    While off-topic, this question to you may prove a route to bringing this on-topic.

    I note you mention repeatedly the "logaricmic nature of the greenhouse effect"  which you see as a factor poorly considered in tackling AGW.  "And I see no recognition of the logarithmic nature of the greenhouse effect, which makes the political problems almost insurmountable."

    The logarithmic relationship between CO2 concentrations and the resulting climate forcing isn't usually seen as causing an "almost insurmountable" problem for AGW mitigation so perhaps you could explain.

  16. cstrouss...

    "Now who is engaging in hyperbole? Are we digging everything we can out of the earth? And if so, who is proposing that we continue doing that? Is the collapse of civilization with continued CO2 emissions also part of the consensus? Documentation?"

    In truth, no, I don't think this is hyperbole since it's firmly based in the realm of possibilities. Human's have an enormous capacity for accomplishments on massive scales. As a species, we have the collective nuclear weapony sufficient to end all life on this planet, possibly permanently (or at least for coming many millions of years). Likewise, oil companies have identified reserves sufficient, were it all burned, to raise the surface temp of this planet to levels that would collapse civilization. And they're continuing to locate more.

    Will we nuke the planet? I hope not but it's not outside the realm of possibilities. In that, it's extremely important that nations of the world work together to manage this possibility.

    Will we burn all those reserves? I also hope we won't do that, but it's even more likely than nuclear armageddon, specifically because there is a massive financial incentive for those oil companies to put their sources of energy on the market.

    I'm a firm believer that the problem we face is a market failure: the failure to price the social costs of carbon emissions. If there were a price on carbon emissions then carbon-free sources of energy would be abundantly cheaper than carbon-based energy. There are a lot of very large companies and very wealthy, powerful people who prefer not to seen their sources of wealth conform to a levelized market. ...because they know they'll lose.

    If you want documentation on the impacts of high CO2 levels, I'll have to do some additional reasearch. It seems pretty clear that nearly all the expected effects of high CO2 will negatively affect agriculture. Increased rain intensity. Increased droughts. Desertification. Increase in pest species. There's a lot of research on this and I've even read a bunch of it. It would just take some time to pull together relevant research. I'm sure there are a number of good articles written here on SkS on the topic.

  17. "Well now we're getting back on topic. Is that your opinion, or do you have studies to back it? This thread refers to several studies that document a strong consensus that AGW EXISTS."

    That's been the subject matter of all the studies listed in the OP here. But perhaps you different expectations of what defines a consensus.

    Here's the way I think of it. Much of the human population doesn't have much of a grasp of what is going on with climate change. In the press this issue gets presented as a 50/50 possibility. Two sides arguing whether this is real or not. The point of all these research papers is merely to say, "Hello! Look here! Nearly all scientists agree this is real and that it presents a significant problem for our planet." I believe all of the 97% of working climate scientists out there would agree with that statement.

    The Cook 2013 paper (noted in the OP) specifically tested the notion that AGW exists but would have minimal effects. That position was very low, inclusive of the 3% of studies.

    If you're looking for something that specifically states how damaging AGW will be, I don't think you're going to find that. This is a question that (as Schneider states in that video) this is a systems problem with a wide range of potential outcomes based on both what we do and how the climate system responds. 

    As Yogi Berra said, "Predictions are hard, especially about the future."

    I don't think there are many scientists who would disagree with the idea that this might not be as bad as we expect. They'd also tell you that a very low probability. There's an equally low probability that this will turn out much, much worse that expected, and that's a very scary possibility on par with nuclear armageddon. The mid-range higher probability outcomes are already very bad if we don't get emissions down quickly. 

    Scientists, as I understand it, are not concerned much about the consensus. They're out there grappling with issues like quantifying the pace of ice sheet melt in Antarctica.

    It's real. It's bad. It's us. These are all accepted. The questions are: how bad? How fast is it happening? How quickly can we get to zero emissions?

  18. Robert S.  "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." 

    Glacial and interglacials are caused by orbital patterns. That has been proven. Interglacials last around 15,000 years give or take some. 


    [PS] I should just point out that you are responding to a comment from 2008. There are 17 pages of comments here.

  19. I think the whole problem I have with this alleged "scientific consensus" claim is the symantic gymnastics it is they engage in. To hear them talk, ALL scientists, or even ALL climate scientists, agree that climate change is happening and humans are responsible. However, and we'll use the Doran study in this example, we find out that actually isn't the case. If we analyze the Doran study and break it down, 10,257 earth scientists were asked to participate in an online survey. Of those, only 3,146 of those asked participated in the study. And, of those 3,146 earth scientists, 5% were climate scientists. That means some approximate 158 of them were climate scientists. Now, surely, there are more climate scientists than 158 and, there's certainly more earth scientists than 3,146 of them and, we can feel pretty confident that there's more scientists than the 10,257 that were asked to participate. So, that certainly isn't ALL scientists as we might be led, by illusion, into believing. Worldwide, I'd like somebody to tell me approximately how many scientists there are in total to qualify any claim that ALL scientists reach this consensus. I'm betting there's WAY more than 10,000, or 3,000 or, 158. So, where do they get off trying to present this illusion that ALL scientists have this consensus. Then, another article I read said that all articles where the abstracts endorse AGW. Well, if the abstract endorses AGW, of course the author is going to endorse AGW as AGW means Anthropogenic Global Warming. Why would they write an article about it if they don't endorse it? And, of course, these people have made it their academic career to be indoctrinated into the AGW camp. If anyone is looking for an objective opinion about AGW, they certainly don't go to someone who has been taught throughout their entire academic career that human kind is responsible for climate change.

  20. Rob Honeycutt:

    Unless you stop breathing, we'll never get to "zero emissions". Further, if you're suggesting that we're somehow going to stop the planet itself from producing emissions? That's not gonna happen. There's no such thing as "zero emissions".

  21. I've been lurking here at Skeptical Science and Real Climate since their inception.  One of the first things I learned was about the natural carbon cycle.  Put that part aside.  The emmissions being talked about are the ones created by fossil fuels.  That CO2 has a different signature from the natural CO2.

    There is such a thing as zero emmissions.  You just have to learn what type is being talked about.

  22. CThompson @819 ,

    I'm sure that you would agree that "scientists" exist on a spectrum of climate expertise, ranging from extensive climate expertise (involving much research & publication in respected journals) . . . . across to those with almost zero knowledge of the complexities of climate-related science (e.g. the 19,000 scientists who signed the Oregon Petition two decades ago).

    Unsurprisingly, all surveys examining this point do indicate that the higher the climate expertise the higher the "mainstream" consensus percentage.

    CThompson, since you seem unhappy to countenance that point, then perhaps you should try coming at the consensus percentage, from quite the opposite direction :-   Identify the percentage of climate scientists who are outside the consensus.

    That would be much easier — since they are so few in number.   And there is an important second identification which you must make.   In order to cull out the undeserving (i.e. the crackpots, the nutcases, and the Gone-Emeritus types undeserving of your approbation) -— you must simultaneously identify the valid evidence which supports their "contrarian" views.

    #   Because if they don't have any valid evidence for their opinions, then they are not really countable as scientists.

    Shouldn't take you long at all !

  23. Unfortunately, CO2's effects on weather are overly exacerbated by scientists who haven't taken the time to study the behavior of matter in depth with respect to radiation. Until they stop talking about CO2 being responsible and move the conversation to H20, they're consensus doesn't mean anything. Study the matter before you make assumptions. CO2 is a miniscule GG compared to H20 and there's not enough of it to make a comparison at this point.

  24. *their, since i can't edit

  25. JBeez , please also edit/correct: "exacerbated".  If English is not your first language, then you can make a post in your Mother Tongue — but you may be slow to get replies.  There are a few posters who make their post that way; but they are usually wise enough to make an English subscript, even if it comes across a bit clumsily (still, readers are tolerant enough to make the best of it).

    If you wish to improve your knowledge of the relative efficacies of CO2 and H2O, then please make your post in an appropriate thread [not this thread].

    Look at the upper left corner of this page :- "MOST USED Climate Myths" . . . and (from more than 100 threads) choose the best fit.  You might care to select Myth 30 or Myth 36 , perhaps.  Read the Basic (and more Advanced versions) and also look through the 100's of comments (some trashy, some very informative).

    That will help you in getting up to speed, on the science of Greenhouse.  Starting from your base position, you may well need rather more than that.  But, it will be a good first step in understanding what the scientists are talking about.

Prev  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  

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


(free to republish)

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