Arguments
Is there a scientific consensus on global warming?
The skeptic argument...
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)
What the science says...
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97% of climate experts agree humans are causing global warming. |
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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. A survey of 928 peer-reviewed abstracts on the subject 'global climate change' published between 1993 and 2003 shows that not a single paper rejected the consensus position that global warming is man caused (Oreskes 2004).
A follow-up study by the Skeptical Science team of over 12,000 peer-reviewed abstracts on the subjects of 'global warming' and 'global climate change' published between 1991 and 2011 found that of the papers taking a position on the cause of global warming, over 97% agreed that humans are causing it (Cook 2013). The scientific authors of the papers were also contacted and asked to rate their own papers, and again over 97% whose papers took a position on the cause said humans are causing global warming.
Lead author John Cook created a short video abstract summarizing the study:
Several studies have confirmed that “...the debate on the authenticity of global warming and the role played by human activity is largely nonexistent among those who understand the nuances and scientific basis of long-term climate processes”. (Doran 2009). In other words, more than 97% of scientists working in the disciplines contributing to studies of our climate, accept that climate change is almost certainly being caused by human activities.
We should also consider official scientific bodies and what they think about climate change. There are no national or major scientific institutions anywhere in the world that dispute the theory of anthropogenic climate change. Not one.
In the field of climate science, the consensus is unequivocal: human activities are causing climate change.
Last updated on 16 May 2013 by dana1981. View Archives
Scientific theories are the best we have (read up on what a theory is). What are scientific 'facts'?
"The greenhouse gas forcings are known with reasonably good accuracy. CO2 (1.4 W/m2) has the largest forcing, but the CH4 forcing is half as large when its indirect effects on stratospheric H2O and tropospheric O3 are included, and the sum of non-CO2 greenhouse gas forcings exceeds the CO2 forcing."
AR4 papers improve on that.
The current knowledge on greenhouse attribution can be
found in Schmidt et al 2010. Got anything that challenges that paper?
"A number of the scientists who took part in the deliberations said they were also dismayed by a growing trend to disregard science."
"On climate change, the scientists warned the global community may be reaching a point of no-return unless there is a push to begin building alternatives to carbon-heavy technologies within the next five years."
You were right the first time - consensus is a majority. In the case of man-made global warming, it's a vast majority (over 97% of scientific experts in agreement), as discussed in the post above.
Perhaps you can clarify here, YellowElephant, as to which scientists disagree. Are they climatologists or scientists in closely-related disciplines? And what is the basis of their disagreement?
To my knowledge, even abject contrarians such as Spencer & Lindzen agree that heat-trapping gases (CO2, CH4, H2O, etc) cause global warming and that humans have emitted significant amounts of long-lasting heat-trapping gases. Their points of disagreement with the mainstream position lie elsewhere.
When over 97% of scientists with relevant expertise agree on the basics of AGW and, as far as I am aware, every major national scientific body (NAS, Royal Society, &c) agree with the major conclusions of climatology as identified by the IPCC, and when even contrarian scientists agree with the basics, then IMO there is no "large debate" going on at all.
Instead, there is what medical blogger Orac calls a 'manufactroversy'(*), where non-scientific interests attempting to defend or upend a status quo rely on various contrary arguments, increasingly of poor quality, to create the illusion of a genuine scientific debate.
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(*) I'm not certain that Orac coined the term, however his use of it is the first I am aware of. (Orac blogs elsewhere under his real name, so my pronoun use is correct.)
As far as the human element goes, I've never heard an argument from a working scientist that makes the claim that we are not the source of the additional atmospheric CO2. I've read the opinion and work of hundreds and hundreds of working scientists who readily accept the mass balance argument corroborated by isotope studies.
If you think you have evidence that there is not a consensus, present it. Change my mind. I take it that you have no time, energy, or training to work on understanding the science yourself. If that is the case (as it is with most of the general population), ask yourself why you believe what you believe. Why believe source X (who argues with great passion but no evidence) rather than source Y (who argues with evidence from a broad range of scientific disciplines).
In theory, yes. Does though assume that scientists behave as scientists ought to, eg making their data available etc etc, and more generally searching for truth rather than pushing an agenda.
Which, when the sole funder of a science is political institutions, may be easier said than done. And so an apparent science consensus may in reality be a political consensus in disguise.
I can't think of a discipline that is not funded by a political institution(s). Solely? Probably not. I keep thinking of Jeffrey Wigand's research while he was working for a tobacco company. He did good work, but he wasn't allowed to publish his findings (often the case with private research). The scientist wasn't the problem, though. Wigand wasn't pushing an agenda (well, not true - he was working on smoke-free cigarettes and that may be why he decided to work for the company); the political institution (the company) was the corrupting force (well, it didn't force Wigand to lie about his findings; it just prevented publication either in physical expression (engineered product) or in sharing with the rest of the world).
The diversification and dispersal of science throughout the university system is a good way to keep politics (in the mainstream sense) from taking a heavy hand in most sciences.
Does anyone have something more recent or definitive?
Abstract
Although preliminary estimates from published literature and expert surveys suggest striking agreement among climate scientists on the tenets of anthropogenic climate change (ACC), the American public expresses substantial doubt about both the anthropogenic cause and the level of scientific agreement underpinning ACC. A broad analysis of the climate scientist community itself, the distribution of credibility of dissenting researchers relative to agreeing researchers, and the level of agreement among top climate experts has not been conducted and would inform future ACC discussions. Here, we use an extensive dataset of 1,372 climate researchers and their publication and citation data to show that (i) 97–98% of the climate researchers most actively publishing in the field support the tenets of ACC outlined by the Intergovernmental Panel on Climate Change, and (ii) the relative climate expertise and scientific prominence of the researchers unconvinced of ACC are substantially below that of the convinced researchers.
Does the statement, “From 82% of earth scientists to 98% of climate experts agree humans are causing global warming.” accurately reflect what the studies show?
It is unclear that the two studies cited here (Doran 2009 and Anderegg 2010) adequately represent contrarian views. Does either study eliminate elitism or biased sampling?
The Doran study was not a random sample, but rather a reflection of about 30% who took the time to respond to an on-line study. The respondents were almost exclusively American. Are there studies or polls from other countries that show similar results?
Anderegg et al started with a database of 1,372 climate researchers based on authorship of scientific assessment reports and membership on multisignatory statements about ACC. “We provide a broad assessment of the relative credibility of researchers convinced by the evidence (CE) of ACC and those unconvinced by the evidence (UE) of ACC.” Their Materials and Methods explains how this was done. “We then imposed an a priori criterion that a researcher must have authored a minimum of 20 climate publications to be considered a climate researcher, thus reducing the database to 908 researchers.” They claim this did not materially alter results, but they later state, “researchers with fewer than 20 climate publications comprise ≈80% the UE group, as opposed to less than 10% of the CE group. In other words, they removed 80% of the initial UE group, and only 10% of the CE,
Can we cite more recent studies, or polls taken among climate scientists of other countries and different affiliations? Sites like World Climate Review will throw an elephant through any cracks we give them.
PROPOSED DISCLAIMER: No poll or survey is perfect. Error margins should be expected.
I'm not aware of any more recent studies, but as it so happens, the SkS team is currently working on the definitive demonstration of the AGW consensus.
Still, trying to play the Devil's Advocate of a contrarian, eliminating (1,372 - 908) of the climate scientists in the first step means that none of these 464 were reflected in the graphs that followed (Fig 1,2,3). Since the UE group is already humbled as being less published than the CE group, not even including them in overall percentages adds insult to injury. Someone may cry “foul”, justly or unjustly. If may look like elitism to outsiders.
From the paper: “The UE group comprises only 2% of the top 50 climate researchers as ranked by expertise (number of climate publications), 3% of researchers of the top 100, and 2.5% of the top 200, excluding researchers present in both groups (Materials and Methods). This result closely agrees with expert surveys, indicating that ≈97% of self-identified actively publishing climate scientists agree with the tenets of ACC (2).” (Doran 2009)
I would have preferred the authors go on to include what % the UE group represents out of the full 908, or even the original 1,372. The authors have made it very clear that the most published and most cited researchers are 97% to 98% CE vs. 2% to 3% UE. That's all well and good. But to stop there seems a little too pat and could raise a contrarian's suspicion that it is contrived to match the Doran results of the previous year.
It leaves a reader with a simple question, “What are the percentages of CE and UE among 'non-expert' climate scientists?” Simple question, but hard to answer from reading their paper.
No, that's not a good reason at all. You've basically stated that if enough authority figures, from prestigious institutions, endorse an idea then we, the general public, should accept it.
I can think of a better reason to accept an idea; examine the merits of it, the evidence both for and against it, weigh the probabilities of it being true, and then come to an independent assessment of its likelihood. If the idea in question is far more likely to be true than not - then, and only then, should you accept it.
You yourself have not read the literature -- that is clear from your other comments. Again, upon what basis do you speak so confidently?
My 'other comments' make it clear that I have not 'read the literature'? Really? In your opinion only.
The body of scientific evidence about anthropogenic global warming is not an “idea”, it is a body of scientific evidence. It would take years for the average person to sift and winnow through each and every cell in this body of evidence in order for him /her to make an informed decision.
If your personal physician determines that you have an illness and recommends a course of treatment, do you sift and winnow through the entire body of scientific evidence about that illness and about the recommended treatment before deciding whether to proceed?
If your personal physician tells you that a specific treatment for your child’s illness is recommended by the American Academy of Pediatrics, do you challenge him/her to explain why he/she is deferring to a higher authority,
I find it odd that you would characterize SkS as a "priesthood" site. It has comment streams. You can ask questions. You can go directly to the science itself. On this site, there are more direct links to the science than at any other climate science site on the net, IPCC included. This is, in fact, the best place to inform yourself. All we need are links to atmospheric science textbooks, but there are links to science of doom, which is about the same thing.
Now consider sites like WUWT. These are the new priesthood you describe. The owners/mods and especially the news sites that are plugged into places like WUWT assume their audience is incapable of understanding the science. They post articles containing really basic errors, and then sit around while the comment stream cheers them on. They engage in rhetorical games like "climategate." The "climategate" allegations, never formalized, are wholly fraudulent, except for one claim (Jones being mean to Soon and Baliunas, but even then there's much, much more to the story). Yet these people knew that their allegations would be swallowed whole by their congregation. They depended on it. And that congregation did not disappoint. They bleated the news far and wide, never once actually checking the claims against what Jones and Mann (and the various independent investigations) had to say.
No, people don't need interpreters. They believe they need interpreters--talk radio, CNN, Anthony Watts.
I'd just like to point out that your opinion of the IPCC is based entirely on what other people have told you to think, based on their own opinions and misunderstandings.
"around 95% of active climate researchers actively publishing climate papers endorse the consensus position"
(-snip-).
According the data one real scientist only can decide that the information about climate is still scarce and there are many unknown components.
(-snip-).
[DB] Please familiarize yourself with this site's Comments Policy; additionally, please read the Big Picture post.
Finally, commenting at Skeptical Science works best if you first limit the scope of your comment to that of the thread on which you post your comment and then follow up on those threads to see what respondents have said in response to you. There are quite literally thousands of threads here at SkS; if you do not engage with the intent to enter into a dialogue to discuss the OPs of the threads on which you place comments, you invite moderation of your comments.
Off-topic and ideology snipped.
C99 - either shenanigans or simply unfamiliar with the history and literature of the theory. Looks like a job for Richard Alley.
http://scienceprogress.org/2012/11/27479/
According to this chap...
"I searched the Web of Science, an online science publication tool, for peer-reviewed scientific articles published between January first 1991 and November 9th 2012 that have the keyword phrases “global warming” or “global climate change.” The search produced 13,950 articles.... By my definition, 24 of the 13,950 articles, 0.17 percent or 1 in 581, clearly reject global warming or endorse a cause other than CO2 emissions for observed warming."
So 99.83% of the peer-reviewed articles relating to climate change available on the Web of Science endorse the theory of AGW. I think that pretty much clears up the consensus debate.
http://www.forbes.com/sites/jamestaylor/2012/03/14/shock-poll-meteorologists-are-global-warming-skeptics/
OR
http://www.ametsoc.org/boardpges/cwce/docs/BEC/CICCC/2012-02-AMS-Member-Survey-Preliminary-Findings.pdf
As it happens, only 52% hold a PhD. Only 56% actively published in the peer reviewed literature in the last five years, and only 12.88% where published primarily on climate change. That is, of those participating in the survey, only 13% have a reasonable claim to be expert on the topic.
As it happens, we know from Doran 2009 that around 88% of Climatologists (excluding broadcast climatologists) believe humans are the primary cause of global warming. A little albebra tells us that 45% of responses to the AMS survey where from climatologists with PhD's who agreed that there was global warming, and that humans where the main cause; an only 6% of them doubted any part of that proposition. That the vast majority of climate change "skeptics" in the AMS are broadcast meteorologists, who may or may not have skills beyond those required to look good on camera and read a weather map. Certainly Anthony Watts has repeatedly demonstrated that you can be a broadcast meteorologist (and member of the AMS) and be clueless about atmospheric physics.
By the way, even the broadcast meteorologists aren't that fond of AGW "skepticism". 70% of respondents thing that humans have caused at least half of the global warming and only 6% claim global warming was the result of natural causes. Likewise, 76% or respondents think global warming will be harmful, with only 2.4% thinking it is beneficial. Consequently your consensus of the non-experts still falls firmly on the side of the IPCC, despite your best efforts to spin the surveys findings.
And, btw, I've talked with plenty of meteorologists who do not understand the basic theory of anthropogenic global warming. Joe Bastardi leaps to mind.
As Christopher Hitchens said, "Since we do not have a spare earth, best to err on the side of caution". Don't you think ?
The signature project has 31,487 signatures, of which 9029 have PHDs, all saying that it is not man made. Makes it hard to believe that there is a 97% consensus.
Kevin, you wouldn't ask your dentists to perform heart surgery. There is an overwhelming consensus in the atmospheric and oceanic sciences. But why look at a consensus of people? Why not look at a consensus of evidence.
Kevin,
Are you as gullible as you seem? Perhaps you should look into those signatures.
Keven @535, some people like to quote raw numbers because they impress the gullible with their magnitude. Less gullible as the question, "31,487 out of how many?"
If it were 31,487 out of 50,000, that would indeed be evidence that there is no concensus among scientists that the late twentieth century warming was man made. As it turns out, there were 56,335,654 residents of the United States in 2009 who held a bachelors degree, or higher. Over the period, 1966-2008, 30.8% of all degrees issued have been science and engineering degrees, so at a reasonable estimate, there were 16.9 million holders of degrees in science or engineering. Or in other words, of those qualified to sign the petition in 2009, at most 0.19% signed it, or had signed it. At most, because signature of the petition are not restricted to US residents, and have been open for many years so that not all petitioners where still living in 2009.
So, in essence, you are claiming that there is no consensus in favour of climate change because less than 0.2% of people with a (any) scientific qualification disagree.
I'm not impressed.
Alternatively, there were 2,348,318 residents of the US with Doctorates (Phds) in the United States in 2009. Over the period 1966-2008, 61.8% of all doctorates have been in science or engineering. Ergo, the pool of candidate signors exceeds 1.4 million, of which only 9,029, or 0.64% have signed.
I am impressed by the chutzpah of your logic, that because 0.64% of all scientists holding a Phd have signed a petition denying the science, that therefore it is not true that 97% of climate scientists agree that humans have caused the late twentieth century warming. But, as I said. It may take in the gullible, but not those with the full facts and figures before them.
Further reading: Meet the Denominator
Data: 2009 Census
NSF report
OK, make that three threads where Kevin has dropped short, content-free comments in the "gotcha"/smear style.
This kind of drive-by commenting reflects badly on you, Kevin.
Kevin, it would be delicious if you marked out the words of others with quotation marks.
You say: "To say that the science is over because of 97% agreement is a pretty arrogant statement to make."
I agree. Now, whoever said "the science is over" is wrong. To say that the basics of the theory of AGW are "settled," though, is right. Settled doesn't mean concretized. It just means that nothing is stirring it up. The basics of AGW were settled over the last century. There hasn't been a serious challenge to the greenhouse effect since Angstrom. The effect has been demonstrated in lab, from satellite, and directly via ground-based instrumentation. Working products have been made that rely on the same principles. The other settled part of AGW is the "A" part. There are no alternative theories where the source of the rise in atmospheric CO2 is concerned. None. And there is abundant evidence that it's us. If you have an alternative that works, you'll be famous.
You say: "I'm sure that there was greater than 97% consensus that Newton was 100% accurate prior to Einstein "proving" that there was more to it."
This is a false analogy. You're suggesting that the levels of evidence for the compared are the same. Not even close. There are tens if not hundreds of thousands of people working in atmospheric and oceanic sciences. The 97% figure was for a small group of regularly-publishing climate scientists. How many people were working on gravity in Newton's day? Even Einstein's day? How robustly were the theories being tested? If you want to see the weight of evidence--the consensus of evidence--see it here. Or see it in the tens of thousands of publications that fill the reference sections of the IPCC ARs.
You say: "All it takes is one falsification to make a theory wrong, to think that "WE" know everything about everything that goes into making our climate what it is is pretty ignorant."
Who said we did? Again, you build this strawman that says, "Climate scientists say they know everything!" No one has ever said that. It's funny: I argue with people regularly who condemn the IPCC for using words like "likely" and "high probability" and "medium confidence." They want science to be absolute. Science refuses to be absolute.
Until you understand the evidence, it will be all too easy to read words like "settled" and "know" uncritically and mistakenly. It is extraordinarily difficult to communicate the science to the public. Everything is interconnected, and so everything needs to be properly contextualized. The "16-year no warming" meme is just the latest great example of that. The denial industry--and it is an industry, from Heartland to GWPF to SPPI and beyond--knows the difficulty, and they take advantage of it. The focus on the words scientists use, ignoring the content of the message. They take words like "consensus" and "settled" and spin them to make them look dishonest or anti-scientific.
And then the public, Kevin, unaware of the game playing, does the heavy lifting by accusing the science and its defenders of being dishonest. Most of the people I discuss the issue with are not in the pay of the oil industry or one of the free market opinion-making organizations. However, some are. There are face-bots, or ideo-bots, created by these institutions solely for the purpose of engaging comment streams with a set of well-oiled memes. These bots never come back to defend their comments. There is nothing to hold them accountable for their misinformation and misrepresentation. Yet there it is, and the public has no basis for deciding what's misinformation and what isn't.
This may explain why you get a strong reaction when you post an evidence-free accusation. It's in the standard playbook for paid denialists. My advice to you is to use questions and refrain from accusations, unless you have the evidence to support them and you're willing to defend that evidence (or change your mind if other evidence is brought to bear).
Kevin, to reiterate; the article above points out that several studies have found 97% of climate scientists accept the evidence that the Earth has warmed, and that human emissions of greenhouse gases is the primary cause of that warming.
Now, you wish to present as counter evidence that less than 0.2% of people in the US with a scientific qualification of any sort disagree. In essence your argument boils down to the claim that:
Less than 0.2% of people with a scientific qualification have expressed an opinion contrary to the consensus on climate change;
Therefore,
It is false that 97% of the scientists best qualified to assess the subject accept the concensus.
Your argument needs only to be stated for it to be seen that it is false.
A useful example of the silliness of some of these polls/petitions is Project Steve, which is limited to people named Steve. It's about evolution, but it has over 1200 signatures now. Is it evidence? Evidence of what? Is there anything special about people named Steve that gives them increased credibility as "experts" in this subject matter?