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barry1487 at 15:01 PM on 20 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
scaddenp.
Barry, how exactly can "double-blind" applied to this methodology?
It does not apply. I mentioned that as but one familiar standard, a strict one. Is there a standard that the methodology for independence follows in this paper? Or is it a unique methodology? Is it normal practise for surveyors to discuss and amend their approach during the initial ratings procedure in this kind of review, or is it unusual? Does the methodology weaken the results? I don't know the answers to these questions.
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Tom Curtis at 14:53 PM on 20 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
"In this hypothetical case the discrepancy is certainly due to the presence of a multidecadal internal variability"
Or it is due to two episodes of opposite sign of subdecadal variablility coincidentally timed.
Or possibly it is due to an incorrect characterization of the forcing agents (ie, the paleoclimatologists got it wrong, not the modellers).
Or it is due to errors in the instrumental record due to reduced coverage consequent on the two world wars.
Or it is due to synergy of two or more oceanic oscilations that do not coincide more than once every thousand years on average.
Or ....
The leap to the AMO is not justified, and is certainly not justified on the AR4 model runs which do not have a systematic error in the post 1950 temperature record which would be there if the AMO was the cause of "systematic discrepancy" in the early twentieth century. If you are to run your argument, you must at least assume the models are in error about the post 1950 forcing response, and hence presumably the pre-1950 responce. Having done that, you are not entitled to assume a "perfect" model will continue to show the pre-1950 discrepancies.
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barry1487 at 14:52 PM on 20 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Rob,
Exactly how many times do you have to do research coming to the same conclusion using different methods before "skeptics" finally admit that maybe the answer is correct?
I don't know which posts you are referring to, but a counter to your point is the "right answer, wrong method" response. This is a particularly apt caution considering the emphasis given by the author/s of this paper to the importance of solidifying public perceptions.
(I'm still mulling over the methodology and haven't yet arrived at an opinon)
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bharath272 at 14:32 PM on 20 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Kudos to you all for the effort!
I am wondering something : did you in any way measure the correlation between the abstract rating and the self rating? The paper mentions only how many papers were rated as endorsing or rejecting or no position under each rating method. It would be fun to see if there are any patterns in the rating of the abstract, which is admittedly subjective, vis-a-vis the self rating....
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KK Tung at 14:29 PM on 20 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
In reply to post 56 and post 59: I must have been a terrible communicator that you both think that I said the opposite of what I wanted to say on some aspects of the problem. So let me try again in a different way. Let us remove the emotions and value judgements by considering a perfect model of our climate, a hypothetical model. Because of chaos, and the hypersensitivity to the initial conditions, we can only hope to simulate the observed forced response, not the observed response which contains definitely both forced and unforced response. To reveal the model forced response, we need to average out the internal variability by ensemble averaging. We need at least 15 ensemble members, each initiated differently. Suppose we have the resources for doing them and we now have the perfect model forced response. Now we want to compare with the observed response, but we do not know what the observed forced response is. But we find the model ensemble mean to under predict the observed warming rate in the first half of the twentieth century. What can we conclude from this fact? By using the word "under predict" I can't possibly be saying the model's forced solution is in error. Remember we said the model is perfect. Is it unfair to the hardworking folks who produce this model to even compare the model with the observation and notice this systematic discrepancy? Notice that I used the word "discrepancy" and not the word "error". In this hypothetical case the discrepancy is certainly due to the presence of a multidecadal internal variability (do I dare to say the AMO?), which is present in this one realization that is our observed climate but not in the ensemble mean model result.
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Daniel Bailey at 14:19 PM on 20 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
"Exactly how many times do you have to do research coming to the same conclusion using different methods before "skeptics" finally admit that maybe the answer is correct?"
Exactly, Rob. Just as the E.P.A. is not required to reprove the existence of the atom every time it approaches a scientific question, scientists need not state a position on climate change in every paper they publish.
This is why the National Academy of Science took the unusial step of referring to the warming of the Earth and the human causation of it as "settled fact" (pages 44 and 45, here). -
scaddenp at 14:09 PM on 20 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Barry, how exactly can "double-blind" applied to this methodology? The conventional meaning is that subject doesnt know whether getting placebo or treatment, and nor does the assessor of the subject response. I'm scratching my head to see how you apply this paper ratings.
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Rob Honeycutt at 13:57 PM on 20 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
This begins to sound something like the hockey stick arguments. "Skeptics" claiming that this study is wrong for one reason, and another wrong for another reason, etc. But there are now over a dozen multiproxy reconstructions that come up with essentially the same conclusion as Mann's original work.
Now we have the consensus issue. Here we have a much larger sampling of data that is coming up with almost exactly the same number as several previous research papers. But there is always this and that nitpic.
Exactly how many times do you have to do research coming to the same conclusion using different methods before "skeptics" finally admit that maybe the answer is correct?
It seems to me this is exactly why we begin to call "skeptics" deniers.
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barry1487 at 13:38 PM on 20 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Dana @ here,
I hope I express Lucia's views properly:
Lucia thinks that if reviewers altered their approach to rating during the first phase of the rating period as a result a result of discussing and refining rating criteria, then this interferes with the notion of independent rating.
I'm not convinced either way, based on what the study methodology purports, but it certainly fails a double-blind test.
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barry1487 at 13:28 PM on 20 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
I think the distinction between accept/reject AGW (options 1, 2 &3) and >50% influence (option 1) is blurred at times in the paper. The paper begins;
Among abstracts expressinga position on AGW, 97.1% endorsed the consensus position that humans are causing global warming
but then strays in the body of the paper.
...there is wide public perception that climate scientists disagree over the fundamental cause of global warming...
...We examined a large sample of the scientific literature on global CC, published over a 21 year period, in order to determine the level of scientific consensus that human activity is very likely causing most of the current GW...
...We classified each abstract according to the type of research (category) and degree of endorsement. Written criteria were provided to raters for category (table 1) and level of endorsement of AGW (table 2). Explicit endorsements were divided into non-quantified (e.g., humans are contributing to global warming without quantifying the contribution) and quantified (e.g., humans are contributing more than 50% of global warming, consistent with the 2007 IPCC statement [consensus?] that most of the global warming since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations)......Among respondents who authored a paper expressing a view on AGW, 96.4% endorsed the consensus....
A careful reading can tease this distinction apart, and one must also be careful to note that a large proportion of the rated abstracts/papers were neutral. It wouldn't matter so much if this was not a study aimed at public perceptions. As Joe Public aren't always careful readers they could come away with the impression that 97% of all the abstracts/studies endorse the 'consensus' that humans are primarily responsible for global warming over the last 50 - 100 years. This distorted reading, helped along by SkS emphasis here and there, is echoed in the press and blogosphere. Eg,
They found over 4,000 studies written by 10,000 scientists that stated a position on this, and 97 percent said that recent warming is mostly man-made.
http://www.accuweather.com/en/weather-blogs/climatechange/new-study-reaffirms-overwhelmi/12560235
The vast majority of scientists who conduct climatological research and publish their results in professional journals say humans are the cause of global warming.
The study went one step further, asking the authors of these papers to rate their entire paper using the same criteria. Over 2000 papers were rated and among those that discussed the cause of recent global warming, 97 per cent endorsed the consensus that it is caused by humans.
http://www.australasianscience.com.au/news/may-2013/consensus-humans-cause-climate-change.html
A survey of scientific papers by a team led by Mr Cook and... found more than 97 per cent of researchers endorsed the view that humans are to blame for global warming.
Of those who a stated a position on the evidence for global warming, 97.1 per cent endorsed the view that humans are to blame.
These statements either state or imply that 97% of rated abstracts (or the subset of those venturing an opinion) agree with the proposition that human activity is responsible for most/all of recent global warming, a misapprehension not undiminished by the full context of the articles.
Is there a breakdown of results for each of the 7 ratings for the whole period in the study or supplementary material? I couldn't find any, which is a disappointing omission for a peer-reviewed survey.
The messaging seems to be successful, but at some cost to scientific rigour, IMO. Advocacy and objective science make uneasy bedfellows.
Moderator Response:[RH] Fixed link that was breaking page formatting.
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KR at 12:37 PM on 20 May 20132013 SkS News Bulletin #12: The Consensus Project
william - One of the underlying issues is that the public perception (and hence the political will to action) of climate consensus is only about 50-50%, rather than the reality of 97-3%. This is in large part due to false balance in the media (one denier for one scientist) and a rather dedicated campaign to heighten uncertainties - see the 2002 Frank Luntz memo for some real horrors in that regard.
That consensus gap is a serious impediment to political action - and (IMO) why this paper is important.
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william5331 at 12:26 PM on 20 May 20132013 SkS News Bulletin #12: The Consensus Project
Playing the consenses card is unscientific, and just gives the deniers ammunition. Climate change is real at the omega 3 level because virtually all the evidence supports it. No need to stoop to the level of the deniers to try to make the point.
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Bob Loblaw at 11:58 AM on 20 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Dr. Tung:
I have been watching the disucssion, but I have been mostly staying out of it. One of the comments policies here at SkS is "no dogpiling", which means SkS does not want one participant to have to deal with comments from a large number of people at the same time. In this case, I have tended to stay out because you, as author of the blog post, may find it discouraging if you have to have multiple conversations with multiple participants at the same time. It is more constructive to keep a small number of conversations going, and avoid having you feel overwhelmed.
Nonetheless, I have been reading, and Dikran has suggested that he'll be dropping out, so I am going to pick up the conversation with one point that you have repeated several times. In #55, you said:
"What it reveals to me is a tendency for the model ensemble means to under predict the observed warming in the early half of the 20th century."
Now here is the problem that I have with that statement, and what I believe Dirkan has been trying to point out in his comments about the spread of the model simulations:
- you have agreed that the ensemble mean represents primarily the "forced response" (at least, better than a single model run would).
- you seem to be neglecting that the observations always represent both the forced response plus the internal variability. It cannot possibly be any other way - the observations include everything. Thus it is, in part, an apples-oranges comparison to look at observation with respect to the ensemble mean.
You cannot come to a conclusion that the ensemble mean of the models is in error (which is what "under predict" is saying) unless you can separate the forced portion of the observations from the internal variation portion. And that is exceedingly difficult.
Even in a single model run, you cannot easily separate the forced and non-forced portions of the response. However, if you run the model a number of times, with slightly different initial conditions, each different model run will have the same forced response, but a different "internal variability" response. Averaging those runs will see the forced response have the same effect on the ensemble mean (thus it will be strongly represented), but the differing internal variability between runs will tend to cancel out and not appear in the mean.
At that point, the ensemble mean no longer tells you about internal variability - but you can look at the entire range of individual model runs to see how far the internal variability can change the results from the forced response.
..and to get back to the observations - as long as the observed temperatures fall along the path that could have happened in any one of the many possible single model runs, then you have to accept that the observations are not in disagreement with what the model has done. After all, if you picked a different model run, you'd see a different combination of forced response plus internal variability - and the model isn't "wrong" until it is different from all single model runs (i.e., it falls outside th range).
In summary, I simply disagree with you that comparing the ensemble mean to the observations is an appropriate test. The ensemble mean could be a perfect match for the real forced response, and the ensemble mean and observations would still be different because the observations include both the forced response and the internal variability.
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Riduna at 11:36 AM on 20 May 2013Who is Paying for Global Warming?
Old Mole – You are quite right. Thank you for pointing out the error in percentages shown as “% of Total Production Exported” in Table 4. The percentages published are wrong - caused by a spread sheet coding error which I should have picked up in the final edit. They will be corrected.
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Riduna at 09:43 AM on 20 May 20132013 SkS Weekly Digest #20
JH - How eminently sensible - and that cartoon, surely one of the best published by SkS!
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KR at 07:44 AM on 20 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
I find discussions like this delightful - although I find myself wanting to wave my arms as I talk, scribbling back and forth on a white-board.
I invariably learn from them, even in the (all too common, sadly) case of finding I was completely mistaken. :)
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CBDunkerson at 07:30 AM on 20 May 20132013 SkS Weekly Digest #20
On the, "If you know of any media coverage which is not listed on the page, please let us know in the comments and we'll add it."... were you looking to include hatchet jobs or not? I note that Watts, Bishop Hill, Tucson Citizen, and other denier outlets that miscast the survey aren't listed... but Science 2.0's article insinuating that it was a non peer-reviewed vanity paper is included.
Moderator Response:[JH] Dana writes the text for the SkS in the News sectuion of each Weekly Digest. That is where the sentence you quote comes from. It is therefore appropriate for him to respond to your question.
As the creator of the Weekly News Roundup and the News Bulletin, I studiously avoid including articles from denier outlets such as the ones you have listed.
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scaddenp at 07:22 AM on 20 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
This has been a very interesting discussion and I would be very disappointed if an aggressive tone led to a premature conclusion. I would really encourage the participants to keep discussing the science. It's rare to see such debate online.
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Jim Eager at 06:01 AM on 20 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Herrhund, first, GCR induced cloud nucleation climate forcing is very far from being an established theory supported by the full body of evidence. But more important, as DSL pointed out, any GCR effect, regardless of sign or magnitude, would in no way negate the radiative physics of CO2 and other greenhouse gases, nor negate the observed fact that burning fossil carbon has increased atmospheric CO2 by ~42%, thereby forcing Earth's energy budget out of balance. Any GCR effect would be entirely separate and in addition to the known anthropogenic enhanced greenhouse forcing, and not in any way be an alternative hypothesis. In short, it would neither endorse nor refute the AGW hypothesis.
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Dikran Marsupial at 03:02 AM on 20 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
I'm sorry Dr Tung, I explained why it is important to look at the spread of the model runs as that is the way in which the models characterise internal variability. You agree with me on this point, as you wrote "I agree with everything you said except the last paragraph", yet you then follow this by "discussing model-observation systematic discrepanices", without reference to the spread of the model runs and concentrating solely on the ensemble mean.
Of course the model ensemble means don't exactly match the observations, but this is not evidence of a systematic discrepancy, it is evidence of a stochastic/chaotic discrepancy, which the spread of the models clearly tells us we should expect to see.
I will now bow out of the discussion. I have explained why I feel your comment was unfair, and explained the two reasons for this, and asked you "Do you disagree with either of these statements? If so, please can you explain why.". I am perfectly willing to change my mind if I am wrong, but if polite questions are asked that are designed to address a misunderstanding, and those questions are ignored, the chance of a productive discussion are rather slim. Note I did not mean to imply that your comments were deliberately unfair.
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KK Tung at 02:07 AM on 20 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
In reply to post 54 by Dikran Marsupial: I agree with everything you said except the last paragraph, where you still accuse me of being unfair to modelers. I am one of them and I had no intention of doing so.
What is nice about this way of communication is that what we said are all recorded. You can go back to reread what I said and see if I was being unfair. My statements were about what we could learn from the models, in particular about model-observation systematic discrepancies. We have looked at both CMIP 3 and CMIP5 model result archives, at individual model's ensemble means where it is available. What it reveals to me is a tendency for the model ensemble means to under predict the observed warming in the early half of the 20th century. I wanted to learn from this model result, while you thought I was a unfairly attacking the hard working modelers. I suggested that the discrepancy was possibly due to the absence of internal variability in the ensemble mean. The ensemble means were not supposed to contain much internal variability. We both agree with that.
The intermodel spread is an entirely different matter.
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From Peru at 01:54 AM on 20 May 20132013 SkS Weekly News Roundup #20B
What happened with my HTML hyperlinks?
Moderator Response:[DB] Manually writing the html results in what you initially saw. The new commenting features incude a WYSIWYG interface. You can highlight your selected text and then click the Insert/Edit Link button to establish a hyperlink to your selected text. I fixed your html in your previous comment.
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From Peru at 01:51 AM on 20 May 20132013 SkS Weekly News Roundup #20B
I am confused by this paper in Nature:
Long-term warming restructures Arctic tundra without changing net soil carbon storage
That shows that at a site where for 20 years there was simulated greenhouse warming, "there was no net change in total soil carbon ( P=0.5) or nitrogen stocks" and "After 14 years of warming, greenhouse plant carbon stocks had increased by 50%"
I am not surprised from the increase in plant (vegetation) carbon, that was already found in other studies, but the "no change in total soil carbon" seems at odds with a lot of papers that studied this problem before.
Any idea of what is going on?
Note on "other papers": I was thinking in papers like this:
The effect of permafrost thaw on old carbon release and net carbon exchange from tundra
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CBDunkerson at 22:45 PM on 19 May 20132013 SkS News Bulletin #12: The Consensus Project
Joshuas193: You can find answers to all of those questions on this site. The list of common issues on the left and the search panel should both help.
1: China is the largest emitter in total and the US the largest emitter per person. However, that isn't the right question. This isn't a problem caused by one, or two, or a dozen countries. Rather, there are only a handful of countries which are not a significant part of the problem. See this link for info.
2: The only currently viable solution is to switch to power sources which do not emit carbon dioxide. Various geo-engineering schemes have been proposed, but none seem likely to work. Many countries have begun clean power programs, but thus far they have mostly just slowed emissions growth. The US is one of only a few countries which has actually been able to decrease emissions... by converting large amounts of power generation from coal to natural gas, but that can only go so far.
3: The tech exists and should actually cost much less than fossil fuels... except that fossil fuels receive massive direct and indirect subsidies which have kept them in use. Unsubsidized solar PV power is now falling below even the heavily subsidized cost of fossil fuels in sunny parts of the world. See renewable power and fossil fuel subsidies.
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MA Rodger at 22:28 PM on 19 May 20132013 SkS Weekly News Roundup #20B
chriskoz @3
The paper by Chen et al is on-line here.
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Tom Curtis at 22:26 PM on 19 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Longhornmaniac8 @134, I believe you've got the idea, but you have your figures wrong. When normalizing the original abstract ratings to allow for detected bias, I get the following for all papers rated:
Total: 11944 (100%)
Affirm: 7349 (61.53%)
Neutral: 4334 (36.29%)
Unsure: 22 (0.18%)
Reject: 239 (2.0%)Ignoring neutral papers, that gives us:
Total: 7610 (100%)
Affirm: 7349 (96.57%)
Unsure: 22 (0.29%)
Reject: 239 (3.14%)So, even adjusting for bias as best we are able with publicly accessible figure, the 97% concensus figure looks very solid, although it is possible that the original abstract rating understated rejections (1.2 vs 3.1%). We should not make the mistake of thinking that normalized figures are superior to the original abstract ratings. They no doubt contain their own biases, and some dubious projections. The figure for "unsure" papers is based on projections from just 5 out of a 1000 papers.
The normalized figures do not supplant the original figures, therefore, but help flesh out how robust those figures are. Various critics of this paper have pointed out a number of possible causes of error (many of which are imaginary). They have not, however, tended to flesh out the criticisms with numerical values. When you do, as you can see, the original figures continue to look very good.
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chriskoz at 20:39 PM on 19 May 20132013 SkS Weekly News Roundup #20B
An interesting article on the shifting poles due to the Greanland melt. Obviously they have the data from GRACE and the data should confirm the SLR contribution by icesheets.
But an interesting aspect is, as Jianli Chen, the lead author says, they have some polar shift data going back 100y. With that data, they can estimate the Greenland melt, hopefully quite precisely for those 100y, well before GRACE. It will an interesting development.
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Dikran Marsupial at 20:14 PM on 19 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Dr Tung, electronic forms of communication have a tendency to be percieved (on both sides) as being more aggressive than is intended. None of what I have written is intended as an attack on you, but is intended to understand your statements and to discuss and correct errors where they appear. That is the way science should work. I find the best way to go about this is to ask direct questions and give direct answers; however when they are not answered this inevitably leads to misunderstandings.
The ensemble mean is the models estimate of the forced response, I think we can agree on that.
Now I would say that the spread of the ensmeble (at least for a particular model) characterises the plausible effects of the unforced response (i.e. natural variability) and the observations can only be expected to lie within the spread of the models runs and no closer. Do you agree with that?
Now you have said that the spread of the models is wide, and I have agreed that it is. However, what I want to know is whether you think there is good reason to expect the spread of the models to be any smaller than it is. This question is intended to help me understand why you appear to think that the models under-predict the warming. As far as I can see it doesn't, the warming lies within the stated uncertainty of the hindcast.
Essentially when comparing observations with models you need to look at BOTH the ensemble mean AND the spread of the ensemble as they are both integral parts of the projection/hindcast. If you only look at the ensemble mean and igniore the spread, you are ignoring the information about internal variability that the model provides.
I'm sorry, but in my view you are being unfair in suggesting the modellers use the ensemble mean because they can't predict chaotic phenomenon, firstly becuase the forced component is the answer to the question posed by the politicians and secondly because they don't ignore internal variability, the spread of their model ensemble is a characterisation of internal variability. If the modellers only used the ensemble mean the comment would be fair, but they don't. Do you disagree with either of these statements? If so, please can you explain why.
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noelfuller at 18:32 PM on 19 May 20132013 SkS Weekly News Roundup #20B
There is some good comment with links on the report on sealevel rise projections just published here:http://www.carbonbrief.org/blog/2013/05/scientists-warn-of-up-to-70-cm-of-sea-level-rise-by-2100,-but-is-this-better-or-worse-than-we-thought -
noelfuller at 18:26 PM on 19 May 20132013 SkS Weekly News Roundup #20B
With respect to the Telegraph story on Fiji villagers moving uphill and others doing the same there is reference made to a new study on sea level rise by 2100 (but no link) where the maximum sea level rise is misquoted as 27cm. In fact the study claimed 27 inches or 69 cm. -
BillEverett at 17:18 PM on 19 May 20132013 SkS News Bulletin #12: The Consensus Project
Joshuas193@11, you can find answers to some of your questions via WBGU-World_in_Transition.doc.
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dhm60 at 16:59 PM on 19 May 2013Trillions of Dollars are Pumped into our Fossil Fuel Addiction Every Year
An intresting piece on one of the denier groups (Intitute for Energy Research) can be found here: www.instituteforenergyresearch.org/2013/04/03/the-imfs-outlandish-claims-about-energy-subsidies/
Standard approach - question the science (Big Oil pay way too much tax) while denigrating the work (outlandish?). I guess the IMF are now part of the great big global AGW conspiracy now. :o That's the IMF - part of the Washington Consensus!
btw: The IMF did a good paper on petroleum subsidies in 2010 entitked "Petroleum Product Subsidies: Costly, Inequitable, and Rising". Worth reading. http://www.imf.org/external/pubs/ft/spn/2010/spn1005.pdf
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KK Tung at 16:42 PM on 19 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
In reply to post 51 by Dikran Marsupial:You have taken my statements on model-observation discrepancy out of context. We all seem to agree that ensemble mean model results reveal the forced response. And we all agree that this one realization that is our observed climate in principle contains internal variability as well as forced response. If model ensemble mean systematically under predicts the observed warming, as happens in the first half of the 20th century, it is legitimate for a scientist to ask whether the difference could be caused by the presence of internal variability in the real climate. To me the discrepancy is revealing and is what we should be learning from models. This is not a criticism of the models. You first claimed that the difference was insignificant because the internal variability is unpredictable by models and quoted AR4 to support your view. Then when I replied that your position was essentially asking us to ignore internal variability you accused me of being deeply unfair and uncharitable to the community of hard working scientists. I am sorry that our scientific discourse has taken this sad turn.
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Bert from Eltham at 16:38 PM on 19 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
There is 100% consensus from the denialist camp on the validity of consensus in scientific matters of peer reviewed papers especially with this peer reviewed paper. Does their opinionated only consensus even negate their own premise? It is a perfect example of circular thinking. Sad. Bert
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scaddenp at 16:00 PM on 19 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Herrhund. There was an interesting review of the CLOUD results at RealClimate which gives some indication of why the research is interesting and worth doing. However, it also outlines succinctly the steps required for the results to even relevant to the question of global climate change. Do you believe new results from CERN are going to advance any of these steps further?
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Joshuas193 at 15:31 PM on 19 May 2013Antarctica is gaining ice
Ok, so I am a noob here. but if I am reading this right there is increased loss of Land Ice in Antarctica and this fresh water freezes easier causing the sea ice to be greater? And even with the rise in temperature it is too small to cause the sea ice to melt. Is this basically the short version of the article?
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jyyh at 15:04 PM on 19 May 20132013 SkS News Bulletin #12: The Consensus Project
please also delete my response to the fretsliders second post, he admitted getting a good response that I didn't see before posting that and delete also this one...
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Longhornmaniac8 at 14:48 PM on 19 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Tom Curtis @ 131,
Thanks for the reply. I see what you're doing there, used it as inspiration to come up with the following values:
Assuming (as you mentioned) there was a false positive on 169 of the abstracts, this means that 622 (791-169) of the papers were listed as endorsing the consensus in both the abstract and self reviews.
This provides us with 1342, the total number of self-reviews endorsing the consensus (622+[.538*1339]).
Using the same assumptions you made, 27 of the papers identified as neutral in the abstracts were self-identified as rejecting the consensus (although this assumes as well that there were no abstracts identified as rejecting the consensus that were self-identified as no position). 27/1339=2.02%.
This leaves us with the remainder of 592, which were identified as netural in both the abstracts and self-reviews. 592/1339=44.2%.
So:
53.8% of No Position abstracts self-review as endorsing the consensus;
44.2% of No Position abstracts self-review as No Position;
2.02% of No Position abstracts self-review as rejecting the consensus.We can use these numbers to slightly adjust the abstract totals to provide a more comprehensive analysis.
37.2% (4447 [3896+720-169 we know were misidentified in the abstract]) were identified as endorsing the consensus in either the abstract review or self-review.
61.6% (7352 [7930-747+169]) were identified as No Position in either the abstract review or the self-review.
1.2% (145 [78+40+27]) were identified as either rejecting the consensus or uncertain in either the abstract review or self-review.Of those papers having a position, 96.8% were identified by either the abstract review or self-review as endorsing the consensus, roughly the same as the numbers used by the authors, but a fun side track nonetheless!
Cheers!
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Joshuas193 at 14:47 PM on 19 May 20132013 SkS News Bulletin #12: The Consensus Project
hi everyone. I'm new here. I have some questions.
Since it appears that pretty much everyone agrees about AGW. We need to start working on some solutions.
1. What/who are the largest contributors of greenhouse gasses? I think i saw that China now puts out nearly twice what the US does.
2 What can be done to lessen or stop this. Are any of the major polluters doing anything to stop ?
3 Are there current technologies that can be implemented now to reduce the greenhouse gas levels. Is it a funding issue or is the tech not there yet?
Anything you can answer/or links you can provide would be appreciated.
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Tom Curtis at 11:27 AM on 19 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Over at Lucia's Blackboard there is a largely irrational discussion of the paper, but Lucia raises one interesting point. Many of the papers implicitly accepting that >50% of late twentieth century warming is due to anthropogenic causes are papers looking at the consequences of that warming. Contrary to Lucia's assumption, most (65.45%) such papers ended up being classified as neutral, but never-the-less her idea of first classifying papers by the IPCC Working Group to which they belonged, and only classifying WG1 papers by level of support for the concensus. In her opinion, only WG1 papers are relevant to the issue.
Fortunately, the searchable database subclassifies papers as Impacts (equivalent to WG2), Mitigation (equivalent to WG3), and Methods and Paleoclimate (equivalent to WG1). Using that feature it is simple to determine that 92.94% of "WG1" papers that state a position affirm that anthropogenic forcings are responsible for >50% of recent warming; while only 7.06% deny it. So, even using Lucia's classification it is clear a consensus exists.
The problem is, I believe Lucia's classification to biased. She motivates it by talking about acceptance of AGW by biologists, and asking just how relevant that is to assessing the consensus. She ignores the fact that many "impacts" and "mitigation" papers look at the effects of global warming on the hydrological cycle, or frequency of storm events, etc. Assessing these issues requires a large overlap of skills with those required to assess the direct effect of CO2 on temperature (and are often done by the same people). Lucia's classification merely excludes a large number of papers that are relevant, and in a maner which biases the result.
Even biological impact papers are arguably relevant to the concensus, in that the biologists must at least make themselves familiar with the detailed predictions to write such papers. However, even accepting Lucia's point on this detailed classification, she has not shown that excluding them will have a significant impact on the survey results.
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Roger D at 11:00 AM on 19 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
It seems in some opinion pieces that deny the consensus (and at the same time propose that consensus in science is not important) there is a curious inability to understand the basis of the 97%. For example in: http://tucsoncitizen.com/wryheat/2013/05/18/cooking-consensus-on-climate-change/
In which the author writes:
"The actual findings of the survey, in Cook’s own words: “We find that 66.4% of abstracts expressed no position on AGW, 32.6% endorsed AGW, 0.7% rejected AGW and 0.3% were uncertain about the cause of global warming.” So how do you get a 97% consensus out of that?"
Somehow, even though the opinion piece itself expicitly includes the qualifying statement that the 97% figure is for papers addressing the cause of global warming (i.e. 33.6% of all papers surveyed), these "skeptics" are still confused. Hard to believe that something so basic can stump them.
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Tom Curtis at 09:50 AM on 19 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Longhornmaniac8 @129, relevant information is in Table 5. Assuming that no paper rated as endorsing AGW based on the abstract was rated by its authors as rejecting AGW (and vice versa), from that table it can be seen that, of papers rated as having no position, or being undecided on AGW and which were self rated, 551 (41.25) where rated as self rated as affirming AGW, 761 (56.8%) were self rated as neutral or having no position, and 27 (2%) were self rated as rejecting AGW.
The discrepancy is no doubt because some papers rated from the abstract as affirming AGW were self rated as neutral. In fact, approximately 169 (21.4% of affirmation rated papers) must have been rated as affirming AGW by the SkS team, but self rated as neutral. Even though the survey generated some false positives, the ratio of false positives to false negatives is 0.4, indicating a strong conservative bias in the rating method.
Looking at a total comparison of abstract rated to all self rated papers, it is evident that the SkS rating team showed two distinct biases (in aggregate). There was a very strong bias towards rating papers as neutral which applied across the board. There was a weaker bias to rate rejection papers as neutral shown by the larger self rated/abstract rated rejection papers (3.25) than for affirmation papers (1.7).
The former is discussed in the paper, and is largely attributed to the reduced information in the paper, but I am inclined to think is in significant part due to too conservative a methodology. The later is not discussed. Some residual personal bias cannot be entirely excluded, but it is more likely (IMO) to be due to a tendency among rejection papers to hide that rejection deep in the paper in a few lines that are not, in fact supported by the rest of the analysis (as for example, in McLean et al, 2009).
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Alexandre at 09:19 AM on 19 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
My German is not as good as it used to be, but this link herrhund posted looks a lot like statements from a Brazilian 'skeptic' meteorologist (Luiz Carlos Molion): vague claims, supported by vague inductive reasoning. In the German case, some visual correlation between sun spot activity and temperature (not always global). In the Brazilian case, visual correlation between PDO phases and global temps. No quantification of effects, no error bars, no statistical analyses.
To those who want desperately to find some article with graphs and figures saying they are right, that's enough. If you don't have science, an article like that is as good as it gets...
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John Hartz at 08:07 AM on 19 May 20132013 SkS News Bulletin #12: The Consensus Project
miffedmax:
No surprise there given how Deniersville is merely an echo-cahmber, full of sound and fury, and signifying virtually nothing.
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Longhornmaniac8 at 07:32 AM on 19 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Great work, SkS team!
One complaint I have (or perhaps just missed) is a relative lack of discussion of the No Position papers and their self-ratings.
You mentioned at the end of page 4:
"Among self-rated papers not expressing a position on AGW in the abstract, 53.8% were self-rated as endorsing the consensus."What about the other 46.2%? Needless to say, it would somewhat undermine your conclusion if of the No Position papers that were self-reviewed, the entire remainder rejected the consensus. Now, I'm 99.9% sure that wasn't the case, but unless I missed it, I don't see any further discussion of the self-reviews of the No Position papers.
Could an author perhaps provide some additional insight to go along with that 53.8% figure? Of the remainder, what percentage self-identified as "rejecting" the consensus, and what percentage self-identified as "no position."
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gws at 06:14 AM on 19 May 20132013 SkS News Bulletin #12: The Consensus Project
The Financial Times link seems already behind a paywall, at least when accessed from here (Norway)
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miffedmax at 05:36 AM on 19 May 20132013 SkS News Bulletin #12: The Consensus Project
I haven't done a thorough search, but it sure seems a lot of the denier blogs closed their comment sections immediately after challenging the 97% claim on pretty much the same grounds as fretslider.
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dana1981 at 05:00 AM on 19 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Note that I tweaked the first sentence a bit to add some precision.
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DSL at 03:42 AM on 19 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
herrhund: "Why are the CERN physicists focusing on cosmic rays when it is correct what Jim Eager said about that there are no theories supported by the full body of evidence?"
Herrhund, the cosmic ray theory is not a comprehensive theory of climate change. It is not an alternative to the theory of anthropogenic global warming. If Svensmark turned out to be right about cloud seeding, CO2 would not suddenly stop absorbing/emitting radiation at various pressure-broadened bands in the thermal infrared range. You also fail to understand what's working against Svensmark. That, in fact, strongly suggests that you're not concerned with scientific progress but rather finding anything (no matter how collectively incoherent) that supports your current understanding of the world.
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DSL at 03:34 AM on 19 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Otiose: "It's very possible in a decade or two science historians will cite this paper as an example during the period in question measuring the degree to which politization was successful in defending a parituclar view or set of views in the climate field and not a measure of the validity of the science."
Yes, Otiose, it is possible. Now, tell me how probable it is, and give me the evidence upon which you base your answer.
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