Arguments
The 97% consensus on global warming
What the science says...
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97% of climate experts agree humans are causing global warming. |
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Climate Myth...
There is no consensus
The Petition Project features over 31,000 scientists signing the petition stating "There is no convincing scientific evidence that human release of carbon dioxide will, in the forseeable future, cause catastrophic heating of the Earth's atmosphere ...". (Petition Project)
Science achieves a consensus when scientists stop arguing. When a question is first asked – like ‘what would happen if we put a load more CO2 in the atmosphere?’ – there may be many hypotheses about cause and effect. Over a period of time, each idea is tested and retested – the processes of the scientific method – because all scientists know that reputation and kudos go to those who find the right answer (and everyone else becomes an irrelevant footnote in the history of science). Nearly all hypotheses will fall by the wayside during this testing period, because only one is going to answer the question properly, without leaving all kinds of odd dangling bits that don’t quite add up. Bad theories are usually rather untidy.
But the testing period must come to an end. Gradually, the focus of investigation narrows down to those avenues that continue to make sense, that still add up, and quite often a good theory will reveal additional answers, or make powerful predictions, that add substance to the theory.
So a consensus in science is different from a political one. There is no vote. Scientists just give up arguing because the sheer weight of consistent evidence is too compelling, the tide too strong to swim against any longer. Scientists change their minds on the basis of the evidence, and a consensus emerges over time. Not only do scientists stop arguing, they also start relying on each other's work. All science depends on that which precedes it, and when one scientist builds on the work of another, he acknowledges the work of others through citations. The work that forms the foundation of climate change science is cited with great frequency by many other scientists, demonstrating that the theory is widely accepted - and relied upon.
In the scientific field of climate studies – which is informed by many different disciplines – the consensus is demonstrated by the number of scientists who have stopped arguing about what is causing climate change – and that’s nearly all of them.
Authors of seven climate consensus studies — including Naomi Oreskes, Peter Doran, William Anderegg, Bart Verheggen, Ed Maibach, J. Stuart Carlton, and John Cook — co-authored a paper that should settle this question once and for all. The two key conclusions from the paper are:
1) Depending on exactly how you measure the expert consensus, it’s somewhere between 90% and 100% that agree humans are responsible for climate change, with most of our studies finding 97% consensus among publishing climate scientists.
2) The greater the climate expertise among those surveyed, the higher the consensus on human-caused global warming.
Expert consensus results on the question of human-caused global warming among the previous studies published by the co-authors of Cook et al. (2016). Illustration: John Cook. Available on the SkS Graphics page
Scientific consensus on human-caused global warming as compared to the expertise of the surveyed sample. There’s a strong correlation between consensus and climate science expertise. Illustration: John Cook. Available on the SkS Graphics page
Expert consensus is a powerful thing. People know we don’t have the time or capacity to learn about everything, and so we frequently defer to the conclusions of experts. It’s why we visit doctors when we’re ill. The same is true of climate change: most people defer to the expert consensus of climate scientists. Crucially, as we note in our paper:
Public perception of the scientific consensus has been found to be a gateway belief, affecting other climate beliefs and attitudes including policy support.
That’s why those who oppose taking action to curb climate change have engaged in a misinformation campaign to deny the existence of the expert consensus. They’ve been largely successful, as the public badly underestimate the expert consensus, in what we call the “consensus gap.” Only 16% of Americans realize that the consensus is above 90%.
Last updated on 8 May 2016 by BaerbelW. View Archives
bakertrg:
Your posts give me the impression that you are badly overstepping your subject matter knowledge, your claims to the contrary notwithstanding. They also give me the impression that you aren't sufficiently skeptical regarding the claims advanced by climate science deniers, your claims to the contrary notwithstanding.
For example:
Completely incorrect.
(1) In this recent article, Dana provides a summary of several attribution studies, which quantify the contribution of anthropogenic effects vs. the contribution of natural effects over the past 50-65 years. You will note that most of the anthropogenic contributions either hover around or well overshoot 100% (because natural effects over that time period have been causing cooling).
(2) How do you know "we're simply not experiencing global warming beyond what has repeatedly been experienced in the past". Sources, please. What is more, past global warming has included both minor and mass extinction events (e.g. PETM, Permian-Triassic extinction) so even if current warming is in line with what's repeatedly been experienced in the past, it doesn't follow that either the process of warming or the end result are desireable from the perspective of maintaining an advanced, affluent, complex human society based on creating reliable surpluses of food for 7.5+ billion people.
As for this portion of your specific response to me:
As a matter of fact, global warming as a technical term is a subset of (global) climate change. If the global climate is changing, and the change is the result of an increase in the global temperature, global warming is an accurate description. Adding anthropogenic to the term merely (and accurately) indicates the cause of the warming. What is more, the political decision to split hairs over the two terms was launched, not by Al Gore or environmentalists, but by a Republican political strategist to sow confusion about the subject. See here for details.
The bottom line is that you are coming across as:
- being ignorant (as in lacking sufficient knowledge) of the topic,
- projecting your lack of knowledge and biases onto others (and especially onto the actual body of evidence), and
- tiresome to deal with, since many of your claims are trivially easy to recognize as faulty, flawed, or outright false, but require a great deal of hyperlinking and typing to address publicly (hence the Gish Gallop).
bakertrg
I agree with others that you need to read a lot more with an open, if critical (but not cynical!) mind.
If you agree global warming is happening across the atmosphere, oceans and cryosphere all together, then you are forced (due to conservation of energy) to presume that the heat balance for the planet is changing. There are only three ways that change can happen: increasing output or radiation from the sun, reduced albedo due to lower atmospheric aerosols, and increasing greenhouse gas concentrations. All other causes of net heating that we know of are trivial.
The warming since 1970 has occured despite no net change in solar output, and maybe a slight decline. There was also fairly frequent volcanic production of aerosols that should have cooled the earth. The only major forcing that changed over this period were greenhouse gases (CO2, CH4, N2O). The lack of correlation between warming and the other natural factors that could warm the earth is just as important as the correlation of warming with CO2.
Scientists aren't satisfied with that though. They also found the effect of CO2 on climate is entirely consistent with physics — in fact this knowledge predates the correlation between CO2 and temp. You simply cannot build a physical climate model that reproduces the current warming from variations in solar radiation and volcanic aerosols alone. People have tried.
Scientists then found fingerprints in the stratospheric cooling, spectral profiles of IR emission to space and back to earth, and in relative heating of nights and days that are consistent with hypothesis that the change is due to the greenhouse effect. The warming is also consistent with climate sensitivities estimated from warming events in the historical past, and in the paleo record.
So, to argue against the observed changes being anthropogenic, you are left to somehow argue that CO2 is not human derived. Unfortunately, the human origin of atmospheric CO2 has been proven beyond doubt using multiple lines of evidence well before the IPCC was even formed - in fact that knowledge was one of the reasons the IPCC was formed!
That is the basis of the scientific consensus. You have to realize that sometimes scientific findings align simply because nature is giving us a clear signal, and this is one of the clearest I've seen in my experience as a scientist.
franklfkin... It would be incorrect to call those negative trends. None of the trends you listed can be determined to be negative since they can't be statistically determined to be different than a zero trend.
GISS: 0.022 ±0.157 °C/decade (2σ)
NOAA: -0.003 ±0.145 °C/decade (2σ)
HadCRU4: -0.009 ±0.141 °C/decade (2σ)
HadCRU4hybrid: 0.054 ±0.188 °C/decade (2σ)
RSS: -0.060 ±0.252 °C/decade (2σ)
UAH: 0.054 ±0.252 °C/decade (2σ)
One thing I'm just noticing that is interesting, the RSS and UAH data, which originate from the same satellite data, are almost identical except for the "-" sign.
(snip) Despite how my posts are being characterized I'm not intent on being a dissenter I am just skeptical of some of what is here and any website pushing that 97% number so hard and calling it the consensus makes me VERY skeptical of both the message and the messenger.
Sorry if I offended you with my retort Dikran, not my intent but I felt you totally mischaracterized my post drew a conclusion I never made and sent me off to read sources that don't refute my point, aren't relevant to the issue and actually support my position not yours.
(snip) One of his arguments was that the papers in the 97% number actually don't say man is the main cause of global warming... which is exactly my leaning. I'm not emotionally vested in this idea, it's just the best answer from the data I have actually researched.
next paragraph
so 97% of scientists are taking the position that THE cause of global warming is anthropogenic but none of them are publicly stating that humans are the cause of climate change? Maybe I'm missing something but that seems to contradict itself.
Despite what it may appear to be my goal is to find answers. I am skeptical of some of the things that are held to be incontrovertible here. My main question and the reason I'm posting on this thread is because I strongly disagree with the methodology for coming up with the number 97%. It seems that a lot of scientists think that humans are A cause of global warming and the graphic takes a huge liberty with meaning by saying humans are THE cause. The meanings are vastly different. I have tracked down some of the papers I'm going to see how many say THE cause.
I'm not a climatologist, I do have a background in physics, computer science and engineering, I have no dog in this fight other than I truly want to know what is happening on our planet if not solely for my edification so that I can at least educate my kids to the best of my ability and speak intelligently on the subject which potentially has massive ramifications going forward. In any event I am honestly trying to address each counter to my initial post (despite what is pretty close to being dog piled which is my reading comprehension is any good turns out to also be against the comment policy)
I see the words "easily disproven", but I actually thought it was accepted fact that we have had cooling trends during the modern industrial period despite ever rising CO2 levels. I posted 1900 to 1940 because I believe I read that on this website but in actually going to look I found some different time lines that had downward trends. 1880 to 1915 or 1940 to 1975 would have been a better example for me to use, I stand corrected.
http://www.geocraft.com/WVFossils/last_200_yrs.html
In any event, the point still remains the same, if the CO2 level is constantly rising and the causation is as great as is being purported shouldn't we see an accelerating temperature change? According to information IPCC admittedly can not explain temperature has been flat for the last 17 years. That is very difficult to explain if the problem is accelerating and even suggests that the causation is either much smaller than alarmists suggest (small enough that mother natures natural variance swallowed it whole) or the link to causation is less strong than you're suggesting.
dr don easterbook gives a fairly informative view both in text and video (though my research shows that he has taken money from the koch brothers) sadly, many players in this discussion have taken funding from one side or another and/or have a book centric profit motive to push their beliefs. Richard Lindzen also falls in this same space. Unfortunately it's hard to determine what came first the ideology or the funding, of course the non consensus supporters are going to look for scientists who share their ideology to champion the cause so it's not surprising that the guys who get funded by big business have the anti AGW ideology. (snip)
The video is long but interesting and he does seem to have quite a bit of data. video the text can be found here and has a lot of great information. Dr Lindzen also offers some pretty compelling video's and his credentials are top notch. That being said his monetary incentive made me watch both videos with a very jaundiced eye. I found him to be pretty credible but I'm always skeptical of people getting paid for their science by a source that only wants a specific outcome.
KR - I briefly looked at Spencer Weart and despite being a believer in global warming comes out against a recent argument for the consensus here. His post about the flawed assumptions in the paper from PNAS made me think he's at least interested in being objective. A very telling point of his post (made on this very website) here poses a big problem for the 97% number. He states that while he is convinced by the evidence, he is surprised by the number who are not. Doesn't appear as if he believes it's only 3% dissenting. He pointed to several reasons why that number could be skewed and he's a recognized figure on your side of the argument.
[TD] See "CO2 Is Not the Only Driver of Climate," and if you want to discuss that topic do so there or on other relevant threads, not here. You are incorrect that there has been no warming in the past 17 years; there are many relevant threads for that topic, but you might start with "What Has Global Warming Done Since 1998?". Further discussion of those topics on this thread will be deleted without warning.
[TD] Don Easterbrook is most definitely not "informative." Just one of many places where his inaccuracies are revealed is here. Richard Lindzen's errors are numerous; one explanation is here.
[PW] Your moderation complaints have been snipped, and you've been given Warning #1: You continue to argue in bad faith, you continiue to play word games, you continue to misrepresent other poster's words, and you impute dishonesty from them, too. Cease, or Warning #2 will be your last.
A cursory glance at Cook et al. 2013 shows that only levels 1-3 are included in the consensus; they explicitly or implicitly agree that most of the warming since 1950 is anthropogenic. A cursory glance at Dr. Spencer's claims places them somewhere in levels 5-7, which aren't part of the consensus.
bakertrg - I expect you will be subject to moderation, due to claims that people are presenting deceptive opinions due to financial renumeration. That said:
Although Spencer Weart has expressed concerns about a particular study (Anderegg et al 2010), you do not appear to have read his actual comment, which states:
If Weart feels that 2-3% rejecting the consensus is a high number, he is hardly disagreeing, now is he? It appears his concerns were with the methods of that particular study, and not the conclusion of an overwhelming consensus. Curiously, you present your information linking a website that appears to be a blog from someone in climate denial, which only reinforces the impression that you, too, are in climate denial. In fact, the more you write, the less interested (IMO) you appear in actual science. It's rather sad that the only lesson you take from Weart is an out of context of a single paper, rather than the copious work on the basics of climate change that I pointed you to. Your reading appears to be rather selective...
Incidentally, Dr's Spencer and Lindzen are quite familar names, as they have quite a history of climate denial themselves - see here and here.
bakertrg - Also note that Anderegg 2010 (which you seem to be criticizing by proxy in your last post) used completely different methods than Doran 2009, or Cook et al 2013, or Oreskes 2004.
Yet _all_ of these studies found an overwhelming consensus among scientists, driven by the evidence they they know of, that the dominant cause of recent climate change is anthropogenic. And replication via different methods is one of the foundations of good science.
Unless you can present evidence (you know, actual data) that this consensus does not exist, I'm going to have to conclude that (a) you're wrong about the consensus, and (b) you're suffering from confirmation bias and are just not interested in the facts.
bakertrg... Please note that moderation complaints get deleted.
If you challenge a piece of published research, do so by backing your statements with references. If you think Doran was a poor survey, show references that confirm it was poor methodology. Don't just state it with opinion, present why you believe that to be the case. Show research on survey methodology that states why the results are not robust.
I have said this before…the idea that the consensus is evidence of some sort of greed-induced conspiracy among scientists completely baffles me as a scientist. Yes, individuals care about getting grant money to support or students and technicians, but it’s not like we are all friends and family living off a common bank account. We often criticize each other strongly, sometimes with vitriol, about things noone else seems to care about. We compete with each other for limited money and review each others grants, sometimes agressively.
If I sense someone is falsifying results, I have every incentive in the world to attack them, especially if they are doing different research than I and getting money that I could get. Heck, I even get famous if I overturn their accepted wisdom. And I could make much much more being a shill to vested interests who would prefer we deny climate change. If money were really the main factor here you’d see a lot less of a consensus.
The fact that I do not know a single scientist who rejects the idea of AGW, despite differences I have with them on a multitude of other issues, is an indication of the power of the scientific arguments supporting it, and the commitments of scientists generally to following the evidence. Nothing in any of the surveys is inconsistent with that impression.
Contrary to bakertrg’s cynicism, I find it all rather uplifting. If only I could figure out why bakertrg hates me, I’d be a happy camper!
bakertg:
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franklefkin @598, thankyou.
I should have checked more closely before responding to the latest denier cherry pick on temperatures. As it stands, my claim that bakertrg's claim re 21st century trends being "trivially false" needs to be withdrawn. It is merely obviously false.
Obviously false because, firstly, with five established temperature records, claiming a negative trend with two of them show a positive trend is begging the question as to which record is superior. We can, off course, look for a tie breaker among the records. Noticing, however, that the only surface record with truly global coverage, and the satelite record with the greatest covered area both show positive trends shows the negative trends of the others to be due to information they exclude rather than a property of global temperatures. Further, the fact that newer records (HadCRUT4-hybrid, BEST) also show positive trends corroborates GISS and UAH as showing the better record, as do indirect measures of temperature such as Sea Level rise, and receding glaciers.
Alternatively, we may decide to treat all records alike, and simply take an average - except that the average of the 5 established records gives a positive trend - and including the newer records (HadCRUT4-hybrid; and BEST) makes that postive rend even stronger.
Finally, we need only notice that pushing the start date of the trend back one year (two years for RSS), or the end date back to Dec 2010 to make the trends positgive to see that the negative trend even in those records with the trend depends essentially on a chery picked period.
Regardless of all this, it appears that bakertrg has dropped that claim, so this is now beside the point.
bakertrg wrote "so 97% of scientists are taking the position that THE cause of global warming is anthropogenic but none of them are publicly stating that humans are the cause of climate change? Maybe I'm missing something but that seems to contradict itself."
do yourself a favour and go and read the paper and the comment thread to see what has been discussed already. Most papers on climate change are independent of whether the cause of the change is anthropogenic or natural. To give you an example, I have worked on statistical downscaling, which attempts to estimate the effects of large scale atmospheric circulation (which GCMs model fairly well) on local (e.g. station-level) scale (which GCMs fundamentally can't do beause the grid boxes they use are too large). A paper on statistical downscaling doesn't need to make any statement at all on what causes climate change because that is not what the paper is about and academic papers tend not to make assertions that are not directly justified by the analysis given in the paper. There are many other topic in climate change that are not concerned with attribution, which is why relatively few explicitly take a stance.
Now this will be obvious to anybody that understands the culture of scientific publication. Scientists do have better things to do with their time than answer questions raised on climate skeptic blogs, and as a result, you will only generally be assured of a climate change paper taking a stance on the cause of the change if the subject of the paper is an attribution study.
"Despite what it may appear to be my goal is to find answers. "
Then perhaps next time someone answers your questions, you shouldn't accuse them of being disingenuous and copping out. This is especially true if you are going to convert
"97% of the papers that take a position on the question do take the position that it is mostly anthropogenic."
and
"If you want a study of scientists that are publicly stating that humans are the primary cause of climate change, then you won't find one, because scientists have better things to do"
into
"97% of scientists are taking the position that THE cause of global warming is anthropogenic"
EMPHASIS yours.
to me it seems this study came about because:
"the skeptics don't believe that, when surveyed, climate scientists tell the truth about AGW and instead endorse it"
So, this study studies the papers instead of surveying the scientists, as it can be assumed that they are more likely to state their correct position in their papers.
The study came up with 32% Endorse AGW.
How do we get to 97%?
"oh...we surveyed them"
:-|
[JH] You are skating on the thin ice of sloganeering whcih is prhobited by the SkS Comments Polcy.
Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.
Please take the time to review the policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.
Mytheroo... I would highly suggest you take the time to read the research paper you're commenting on. The answer to the question, "How to we get to 97%?" is there.
Of papers that take a position, 97% of the published research supports the idea that humans are the primary cause of warming.
If you like, you can use the 32% figure too, but you have to compare that, then, to the rejection rate which goes down below 1%.
No matter how you prefer to slice it, the overwhelmingly dominant position in the published literature is that human emissions of CO2 are the primary cause of warming.
Is it too much to ask that people read just the infographic?
97% ? Pfff... Until 1887, 100% of scientists agreed on the existence of aether...
Murmur, it is absolutely given that a consensus does not make a theory correct. However, this is article is putting to bed the myth that there is no scientific consensus. For policy makers, going with the consensus is the only rational choice. If you were ill, would you be like this guy? It's not like there is any other credible theory of climate.
Has skeptical science done an article responding to the American Physical Society Framing document on climate science which raised substantial questions on the state of climate science: http://www.aps.org/policy/statements/upload/climate-review-framing.pdf
PhysicsProf, the document you link is worded and presented in a rather peculiar fashion. What is its exact origin?
When I go to the APS website and follow the links, I find this page:
http://www.aps.org/policy/statements/07_1.cfm
It is much more consistent with the normal tone of APS statements, which usually do not contain an abundance of graphs and data, or text highlighted in red. I looked at a variety of other statements and none of them has a format similar to the one you linked. I had too much difficulty to keep the document running on my computer to study it in enough detail, it kept on triggering error messages when trying to scroll. However, I did see a reference to the CimateAudit blog, which I find highly suspicious. APS does not normally refer to blogs of any kind.
Do you know where exactly that document came from? As I see it, it appears more fraudulent than anything else. Did you talk to anyone at APS about it?
I sent an e-mail with the url to APS, hopefully they'll respond in a few days and tell us something on the nature of this statement.
PhysicsProf @618 & PhilippeChantreau @619/620.
The APS is reviewing its statement on Climate Change and the document link given @618 is to a document that was an early part of that process. It is a pukka APS document produced by the sub-committee appointed to look into the review. (It is the "Framing Document for Workshop" mentioned on the page linked above.) It was a sort-of agenda document for a workshop held in January this year. What was curious was the list of experts invited to that workshop. These included obvious suspects (Bill Collins, Isacc Held, Ben Santer) and controversially arch-denialists Lindzen, Curry & Christy. I know of no offical reason for their invite but there was comment I read that this would disarm L,C&C who often claim nobody listens to them. The workshop transcript is available on-line and stretches to 573 pages (of big print).
The next step in the process, a decisionof whether to stick with the old statement from 2007 (which itself got some skeptics grinding teeth) or whether to start a process to develop a fresh statement - that decision has yet to be made. However the whole thing got a lot of airing in March when a professional twit of the British press called Delingpole kicked off a story that L,C&C had been appointed to the committee considering the APS statement review. Although utter bunk, the skeptical twitosphere feasted heavily on this "news" for some days.
So we await the outcome of the sub-committee's deliberations.
"L,C&C who often claim nobody listens to them"
Someone at APS listened enough to bother with yet another ClimateAudit insinuation of impropriety, which I find a little disappointing. Of course, if "skeptics" were part of that commitee then all bets are off...
L,C & C were listened to when they first spoke. As they kept on repeating themselves, the amount of listening they garnered decreased, which is entirely normal and even desirable. Sometimes I wish that the the mass media out there would have the same sloganeering policy that SkS has.
L, C&C receive exactly the attention they deserve from the scientific community and way more than that in the public media, they have no reason to complain.
So I gather the answer to my question is no, there hasn't been an article addressing the concerns raised by the American Physical Society. While Linzen, Curry and Christy were part of the actual workshop, my understanding was the framing document was from the APS without the input of the three. I did read the whole 573 pages of the workshop which was pretty fascinating but most of the questions in the framing document weren't directly addressed. What interests me is the current discussion feels like politicians slamming each other rather than scientists analyzing a problem ("this is all a hoax"--because scientists love secret meetings to fool the public; or "you're a denialist"--because Holocaust imagery is always in good taste). What I liked about the APS document was it asked serious questions a scientist rather than a politician would ask seeking to understand the basic science involved.
PhysicsProf - If and when the APS releases an updated statement, it might be worth commenting upon it to the APS. Right now, it's silly to claim that a draft in progress, particularly with biased committee membership, is the opinion of the society as a whole.
Why would you treat an unapproved draft as the opinion of the APS?
KR @624:
Particularly as it is not a draft, but a "framing document" that may have deliberately set out to encapsulate "skeptical" arguments without either endorsing those arguments or even agreeing that they are sensible, but merely in order garner responces to what are considered to be contrary opinion.