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barry1487 at 13:58 PM on 21 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
KR and Jason,
"Two comments, with the understanding that the "concensus on AGW" means AGW as the dominant force behind global warming:"
"If the abstract says anything that can be interpreted as "human activity is <50% responsible for global warming" it would have automatically shunted it into category 5, 6, or 7"
It seems I have been labouring under a misapprehension, then. But I wonder if I am alone in that. The email sent to original authors makes no mention of the consensus being about degree of warming. The Endorsement statement in the email only mention humans contributing, not being a primary source.
Endorsement: The second drop down indicates the level of endorsement for the proposition that human activity (i.e., anthropogenic greenhouse gases) is causing global warming (e.g., the increase in temperature). Note: we are not asking about your personal opinion but whether each specific paper endorses or rejects (whether explicitly or implicitly) that humans cause global warming:
Then they get the 7 rating options, 2 of which are quantified, and the other 5 are qualified. The Author reading the email it must infer that all 7 ratings are under the rubric of >/<50% human influence, rather than (as I did) view the remaining 5 ratings as qualitative, rather than quantitative options. Scientists must make an assumption about that because it is not expressly stated, and in the manner that it is stated in the email, it does not mention degree of human influence at all.
Neither is it in the abstract of the paper. In fact, apart from options 1) and 7), only one sentence of the paper does mention degree of human influence, in the last sentence of the introduction. I find this confusing. The abstract mentions of the consensus position infers a simple accept/reject AGW. Eg,
"Among abstracts expressing a position on AGW, 97.1% endorsed the consensus position that humans are causing global warming."
Throughout the paper, apart from the one sentence in the intro, the values are tied to the phrase "the consensus" or similar.
Read straight, this could easily include a human contribution of less than 50%, and options 2, 3, 5 and 6, are qualitative options, and nothing to do with >/<50% hmuan contribution. IE, If an abstract seems to minimize the importance of the human contribution and gives no qantification, then it is rated 5 or 6, and if it emphasises the importance of the human contribution, but does not quantify, then it should be rated 2 or 3. (It's a shame a breakdown of ratings results is not included in the study/supplementary)
My concern now is, that with different interpretations of the consensus statement (and different scientific societies and position statements also word the consensus differently, some only going as far as saying that human activity is contributing to global warming), the original Authors may have rated as I did, applying to all but options 1 and 7 a qualitative interpretation of abstracts.
Possibly I am just ignorant or not too bright. They said so at Lucia's, where I have been arguing, against them there, that the 97% result has come from a simple accept/reject AGW. I really do find it incredible that 97% of abstracts endorse >50% human influence, implicatively or otherwise.
BTW, are any of the authors commenting here? It would be great if they did and identified themselves (unless they prefer anonymity), so that they could clear up misunderstandings.
Hey, John Cook, come straighten us out.
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JasonB at 11:12 AM on 21 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Dr Tung,
We are all wasting our time here.
On the contrary, this latest exchange has definitely cleared up some confusion that I, and apparently many others, had about your position. You may feel that the meaning was clear but by continuing to use a word that carries a different meaning to that which you were apparently trying to express, it made it difficult for others to discern.
So this has certainly been productive and should move the discussion forward.
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JasonB at 11:00 AM on 21 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
engineer,
just my 2 cents.
I'd be asking for my money back.
Perhaps you haven't seen my earlier comment, among many others' comments that already addressed this point? Perhaps you can explain why a number that would be invariant regardless of how many irrelevant papers are considered is less important than a number that can be changed at will simply by adding more papers to the set of papers that must be manually considered?
To me, it seems illogical to include papers that are irrelevant to determining the question at hand but I look forward to your explanation.
Especially since the keyword searches used to find the papers, "global warming" and "global climate change," are sensitive topics with proponents pushing for drastic emission reductions.
Are they? Tell me, what topics should researchers use who are simply reporting on some scientific results so they can avoid these "sensitive topics" with unnamed "proponents"? That's what all the papers I looked at were doing, and, as I've mentioned before, all the "neutrals" I saw clearly accepted global warming was occurring (and were reporting on some aspect of the consequences), it's just that they didn't mention the cause of it in their abstracts. Since they did give any indication on the cause, they were irrelevant to the question at hand, just as the vast majority of papers published in the scientific literature. Should they be included in the total too, so the two percentages become ~0% and ~0% (while still maintaining the same ratio)? Or should we focus on the papers that actually have a bearing on the question at hand?
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ColorMeSkeptical at 10:54 AM on 21 May 2013CRU tampered with temperature data
Ummm... How can "Climate Change Email Review" perform an "independent" review that "proves" CRU was hiding nothing when CRU a) refused to release its data, deleting it in the end with the (-snip-) justification that they "lacked disk space" and b) refused to release their source code for independent analysis? How is "refusing to release for truly independent review by any interested party" different from "hiding"?
Moderator Response:[DB] Inflammatory snipped. Note that the Muir Russell Commission performed their independent audit and replication of CRU data sans any source code in a mere 2 days, saying in typical reserved fashion that 'any competent researcher could have done similarly'.
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Rob Honeycutt at 10:54 AM on 21 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
engineer @ 157... Well, no one ignored the "no position" papers. It's discussed quite extensively in the paper.
You're not noting the fact that, when the scientists rated their own papers, that 66% dropped to 35%, yet the consensus figure of papers that state a position stayed nearly the same. That, in and of itself, suggests a level of robustness to the conclusions.
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KK Tung at 10:45 AM on 21 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
In reply to post 70 and 71: I may have used the word "underpredict" and "discrepancy" incorrectly, but the meaning was clear because I elaborated many times and in different ways what I meant. It was even clear from my first mention that I was using the ensemble mean as the prediction of the forced response only. But you keep repeating an erroneous interpretation of what I said, as using the ensemble mean as a prediction of forced response plus internal variability. I never said that. In fact I kept saying the opposite. We are all wasting our time here.
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JasonB at 10:43 AM on 21 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
barry,
Further to KR's comment, the reason I mentioned the 5, 6, and 7 categories was because each cateogory must be considered in the context of all the others. If the abstract says anything that can be interpreted as "human activity is <50% responsible for global warming" it would have automatically shunted it into category 5, 6, or 7, whether it was implying it, stating it, or exlicitly quantifying it.
And if it did not go either way, then it was neutral.
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Roger D at 10:19 AM on 21 May 20132013 SkS Weekly News Roundup #20B
William - OK, fish leaving one area for another with a more suitable water temperature may not be as "serious" as overfishing now. Maybe climate change is miniscule in impact in comparison to overfishing now, but it is a warning that this will be a worsening problem to life as normal. In addition to overfishing, pollution, ocean acidification that may all get worse now we see there is this new and likely growing impact that will probably be a negative. What species will move to the warmest waters? To where will the coldest water species migrate?
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engineer8516 at 09:57 AM on 21 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
First, I would like to commend you guys for putting the time and effort to do this. However, I think the 97% consesus is misleading.
The article states, "We found that about two-thirds of papers didn't express a position on the subject in the abstract, which confirms that we were conservative in our initial abstract ratings."
Thus, the 97% consensus is only for the papers that expressed a position on the topic of AGW. Therefore, out of the total sample size of 12,000, the number of papers that expressed support of AGW in their abstract was actually 32% . And 1% expressed disagreement or uncertainty with AGW. Thus, 67% of the abstracts didn't have a position.
The article further states,
"This result isn't surprising for two reasons: 1) most journals have strict word limits for their abstracts, and 2) frankly, every scientist doing climate research knows humans are causing global warming. There's no longer a need to state something so obvious. For example, would you expect every geological paper to note in its abstract that the Earth is a spherical body that orbits the sun?"
While the first one is true, it still doesn't tell us the author's position. The actual authors may or may not support AGW or maybe unsure. The second one looks like a personal opinion.
It seems illogical to just ignore the 67% of papers that didn't express an opinion in their abstracts. Especially since the keyword searches used to find the papers, "global warming" and "global climate change," are sensitive topics with proponents pushing for drastic emission reductions.
Also that UIC paper that is cited asked 2 questions in its online survey.
"1. When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?
2. Do you think human activity is a significant contributing factor in changing mean global temperatures?"
76 out of 79 climate scientists answered risen to question 1. The 97% consensus comes from the 75 out of 77 climate scientists that responded yes to question 2. But question 2 is subjective because it doesn't state what % is considered siginificant. Significant could be 10%, 20%, 50%, etc of observed warming. just my 2 cents.
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Bob Loblaw at 08:28 AM on 21 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Another thought just popped in. You (Dr. Tung) said:
" Could it be the word "under predict", which to me just means that the model warming is less than the observed warming. I did not attach any value judgement to it."
The problem is that "under predict" is a value judgment. Just as "discrepancy" is. A non judgmental wording would be "the numbers are not the same".
Part of my science training was the importance of making clear distinctions amongst "observations", "interpretations", and "conclusions". Not only is "under predict" not an observation, it is not even an interpretation - it is a conclusion.
And we're "nit-picky" not because we're at Skeptical Science - we're nit-picky because that is what scientists do...
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Bob Loblaw at 08:17 AM on 21 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Busy, so not much time to comment, but I want to stress Dikran's comment in #67, and put it more bluntly:
The model ensemble mean can't be used as a prediction of forced response plus internal variability, and thus is can't "under predict". Regardless of what label you put on it, I think you are over-interpreting the difference.
Also as Dikran points out: you need to get back to the points people have raised about the circularity of the argument. I think that your repeated "under predict" type vocabulary underlies a lack of realization that that you have potentially serious issues related to your methodology. You are interpreting things in a fashion that is not supported by either the evidence or your discussion, but you don't seem to be able to step back and realize that there is an implicit assumption in your work that is not jsutified (and is leading you in the wrong direction).
...back to reader mode...
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John Hartz at 08:01 AM on 21 May 2013Who is Paying for Global Warming?
Also see Who's Paying the Price for Global Warming? a 60 second podcast by David Biello, Scientific American, May 19, 2013.
BTW, Biello's answer to the question posed:
U.S. taxpayers have so far borne the brunt of climate change costs
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dagold at 06:41 AM on 21 May 2013Help close the consensus gap using social media
Hey, Alexandre: Yes, sometimes I think it is necessary to 'leap ahead' and at least put the 'picture' out there of what we want to help bring about. Not in any way, shape or form to compare anything I do or say or write to MLK, but his 'I have a Dream' speech sort of did that.
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Rob Honeycutt at 06:16 AM on 21 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
KR... Well, you know, they don't have much room to play with at 0.7% of the research. ;-)
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Eyal Morag at 05:59 AM on 21 May 2013Was Greenland really green in the past?
The Saga of Erik the Red - Icelandic Saga Database
1880, English, transl. J. Sephton, from the original 'Eiríks saga rauða'.Now, afterwards, during the summer, he proceeded to Iceland, and came to Breidafjordr (Broadfirth). This winter he was with Ingolf, at Holmlatr (Island-litter). During the spring, Thorgest and he fought, and Eirik met with defeat. After that they were reconciled. In the summer Eirik went to live in the land which he had discovered, and which he called Greenland, "Because," said he, "men will desire much the more to go there if the land has a good name."
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Alexandre at 05:41 AM on 21 May 2013Help close the consensus gap using social media
dagold at 05:22 AM on 21 May, 2013
Not likely, I know, but I wish there were more people dreaming of the right things...
Already liked on Facebook.
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dagold at 05:23 AM on 21 May 2013Help close the consensus gap using social media
Okay- think I got the hyper-link inserted now:
www.huffingtonpost.com/davidgoldstein/a-daughters-tears_b_3287465.html?utm_hp_ref=climate-change
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dagold at 05:22 AM on 21 May 2013Help close the consensus gap using social media
Well, here is my latest Huffington Post article with my attempt to generate climate awareness. It is the complete text of the dramatic climate policy speech we all want Obama to make. It's gotten some buzz in the climate world and I am hoping folks will share it enough so that it comes to the attention of Pres. Obama himself. Here it is: http://www.huffingtonpost.com/davidgoldstein/a-daughters-tears_b_3287465.html?utm_hp_ref=climate-change
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Rob Painting at 05:06 AM on 21 May 20132013 SkS Weekly News Roundup #20B
William - actual research demonstrates that the effect of ocean warming on fish stocks is significant. I don't think that anyone here disputes that overfishing is a huge concern - many species are heading toward collapse. These pressures are not mutually exclusive.
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rockytom at 04:38 AM on 21 May 20132013 SkS Weekly News Roundup #20B
#5. From Peru
It may be that the authors used a non-permafrost area to conduct their experiment. Their abstract doesn't mention permafrost (I haven't read the whole article). The main concern about the warming Arctic is the release of methane from thawing permafrost and not the release of carbon from non-permafrost soils over a 20-year period. Maybe someone who has read the whole article can elucidate.
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Dikran Marsupial at 04:35 AM on 21 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
I'm sorry Dr Tung, but there were no accusations of your motives, in fact I clearly stated "I did not mean to imply that your comments were deliberately unfair".
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MP3CE at 04:25 AM on 21 May 2013Help close the consensus gap using social media
I think SkS does this job very good. Perhaps the issue of polluting without paying a price to it should be compared to avoiding taxation at the expense of others, but again, I am not sure about public perception of this as some people do think that avoiding taxation is good and not a cheating on others.
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KK Tung at 04:17 AM on 21 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Replying to post 67 by Dikran: Your comment is well taken. I had suspected that all these accusations of my motives may be due to a word that I used. Instead of the word "underpredict" I should have used a longer phrase "a difference and the difference is negative when taken as the model ensemble mean minus the observation". I will try to be more careful commenting on this site and not use short-hand words. Often when I was busy or in a noisy environment trying to reply using my ipad I tend to write tersely, and it has not worked here.
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Dissident at 04:11 AM on 21 May 2013Another Piece of the Global Warming Puzzle - More Efficient Ocean Heat Uptake
I'm not sure whether this is off topic, but I have read in other threads that there is less cold water plunging to the ocean floor around Antarctica (and presumably the Arctic too) due to the sea water becoming less saline due to increased precipitation and melting polar ice. In the Arctic that can result in a weaker gulf stream in the North Atlantic, while in the southern ocean, would the same mechanism increase the flow of water into the Humboldt current (what doesn't plunge down has to go somewhere) - behaviour of both currents are different due to land mass distribution.
I think the increase in water 'available' for the Humboldt current would automatically make it stronger, would that be a reasonable hypothesis? If that current is stronger, wouldn't the likelihood of La Niña be increased, with an associated increase of polar water migrating to the tropical Pacific, which would affect the amount of heat absorbed by the Pacific?
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Alexandre at 04:00 AM on 21 May 2013Help close the consensus gap using social media
For some time now I'm convinced this issue needs a more skillful aproach - PR wise.
Documents like that joint statement from academies of science are not nearly enough to reach the broader audience. Only a few climate geeks get to read it.
Simple and direct messages are much more suitable for this kind of task. If you could get the endorsement of a few top-rank climate research insitutions, it could be even better (GISS? NOAA? Hadley Center?). I don't think it's beyond the reach of the SkS community.
This project is definetely a step in the right direction. I wish you success.
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william5331 at 03:35 AM on 21 May 20132013 SkS Weekly News Roundup #20B
If the snow pack is melting in the Rockies, providing the water too early for agriculture, they better start encouraging the spread of the Canadian Beaver. They serve the same purpose as glaciers in shifting water from winter to summer, mitigating floods and eliminating catastrophic low water. Read Three Against the Wilderness by Eric Collier to see just how effective beavers were in 1948 when the reverse happen. There was a very heavy snow pack and a much delayed spring. When it came, the floods were incredible and the Frazer Valley Delta by Vancouver had huge floods. Only on Meldrum Creek where Eric had brought back the beavers from near extinction, were the waters held and released slowly.
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william5331 at 03:23 AM on 21 May 20132013 SkS Weekly News Roundup #20B
Trying to blame climate change for a change in fish catches is like when the Canadians tried to blame the seals for the decline of fish on the Grand Banks. (read Sea of Slaughter by Farley Mowat). Yes there may be an effect but it is miniscule in relation to the destruction we have wrought on the fisheries stocks by our amazingly stupid fisheries policies. In the future, climate may be the overwhelming factor but at present it is us.
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Dikran Marsupial at 02:30 AM on 21 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Dear Prof Tung, "underpredict" and "discrepancy" are both words that carry a strong implication that two things should be the same, but aren't.
As we agree, the ensemble mean is an estimate of only the forced response. This means that it is not itself a prediction of observed temperatures. Therefore it is unfair to say that the ensemble mean underpredicts something that it does not actually attempt to predict.
The collins dictionary says this about the word "discrepancy":
"Discrepancy is sometimes wrongly used where disparity is meant. A discrepancy exists between things which ought to be the same; it can be small but is usually significant. A disparity is a large difference between measurable things such as age, rank, or wages"
Now if you had said there was a difference rather than a discrepancy, your statements would have been far less of an issue.
Note this is not nitpicking. There are many skeptical arguments used to criticise models that explicitly or implicitly are based on the assumption that the observations should lie close to the ensemble mean (which would seem reasonable to most, but which we would I hope agree is incorrect). Sometimes these arguments even make it through into publciations in peer reviewed journals, for example Douglass et al (2008). When discussing science for the general public, especially on a contentious subject, such as climate change, it is very important to make sure that ones choice of words is correct and does not propogate misunderstandings.
I offer this in the hope that we can return to the substantive issue, which is the circularity of the proposed method.
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KR at 02:16 AM on 21 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
barry - Two comments, with the understanding that the "concensus on AGW" means AGW as the dominant force behind global warming:
First: The title is part of the definition of the categories, as viewed by both raters and authors. And category 2 "Explicit endorsement without quantification" is just that, endorsement of the AGW consensus. If a paper treats AGW as not the dominant influence, it's not endorsing the consensus, and shouldn't be rated as Category 2. Ratings are not just off the description (a refinement), but also the category title itself. And somehow, I cannot see an author whose paper rates AGW as a minority influence would voluntarily rate it as explicitly endorsing the consensus.
Second: Category 3, "Implicit Endorsement: Implies humans are causing global warming. E.g., research assumes greenhouse gas emissions cause warming without explicitly stating humans are the cause", is a clear endorsement of human caused global warming if you understand that greenhouse gas emissions are caused by humans.
Therefore, unless there is a statement in the abstract or paper that increases in GHGs such as CO2 are from natural causes, rather than anthropogenic (very much a minority view), this is indeed an endorsement of the consensus. Because, quite frankly, the evidence for human driven increases in CO2, CFCs, and the feedback from water vapor is overwhelming.
---
What is most amazing to me in these discussions (here and on sites like the Blackboard) is the push for one-sided filtering: that papers categorized as rejections are always rejections, but that somehow papers categorized as endorsements are not always endorsements. That seems overwhelmingly biased to me...
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KK Tung at 02:05 AM on 21 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
In reply to post 63 and post 65 by JasonB: you and others are asking a different question and a different test than the point I was trying to make. The question you asked was if I claim that the model is in error in under predicting the observed warming what statistical test do I have to prove it. The standard test, which many of you are alluding to, is to test if the mean of all the ensemble members is different from the observation by seeing if it is within two standard deviations of the variance created by the ensemble members. If so then I cannot claim that the model is in error because the difference is random climate noise. My question was different, it concerns forced response vs unforced response. I used the model ensemble mean to approximate the forced response. If I see the forced response is lower than the observation, which contains both forced and unforced internal variability, I tentatively attribute the difference to internal variability that is not and should not be in the ensemble mean. It is tentative because there were not enough ensemble members from any modeling group in CMIP3. I see it happen systematically in most models we looked at with more attention paid to models we trust. I mentioned it previously as an revelation to me, a thought process that is often necessary in science, not a proof in mathematics. You may have a different thought process for discovery. I know of mathematicians who do not proceed to solve for the solution to a partial differential equation until they could prove that the existence and uniqueness of the potential solution.
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barry1487 at 01:55 AM on 21 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Amendment
"I don't believe 97% of papers/abstracts gave exlicit endorsement 1) to the notion that human activity is >50% responsible for global warming. I think 97% of papers gave unquantified + explicitly quantified endorsement that AGW is happening."
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Dikran Marsupial at 01:23 AM on 21 May 20132013 SkS Weekly Digest #20
Hi Tom, I hope the urgent matters can be resolved satisfactorally, I also look forward to your return.
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barry1487 at 01:23 AM on 21 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
A comment disappeared - don't know if my posting status has changed.
Jason, i've read the paper and the supplementary material quite carefully. The supplementary material gives the email sent to original authors with the endorsement statemtn (which mentions nothing about degree of human influence) and the options. Can you explain how options 2) and 3) endorse >50% human influence on global warming? I don't think they do at all. Only 1) specifically states this. The other 2 are unquantified, as the paper attests.I don't believe 97% of papers/abstracts gave exlicit endorsement 1) to the notion that human activity is responsible for global warming. I think 97% of papers gave unquantified + explicitly quantified endorsement that AGW is happening.
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barry1487 at 01:17 AM on 21 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Jason,
Did you actually try the rating exercise yourself?
Yes, twice in the public survey rating the 10 abstracts. The second time i loked up the full papers to see how the full text compared with the abstracts. I found, as most others did, that the full papers were more likely to express an opinion that the abstracts. I believe I understand what neutral means, and I certainly don't think it implies a rejection of the consensus. But neither does it imply endorsement.
I disagree that options 1, 2 and 3 support an endorsement of the anthropogenic influence of global warming is greater than 50%. only option does.
2) Explicitly states humans are causing global warming or refers to anthropogenic global warming/climate change as a known fact
3) Implies humans are causing global warming. E.g., research assumes greenhouse gas emissions cause warming without explicitly stating humans are the cause
The endorsement statement in the email received by original authors is given in the supplementary material.
Endorsement: The second drop down indicates the level of endorsement for the proposition that human activity (i.e., anthropogenic greenhouse gases) is causing global warming (e.g., the increase in temperature). Note: we are not asking about your personal opinion but whether each specific paper endorses or rejects (whether explicitly or implicitly) that humans cause global warming:
Can you explain how options 2) and 3) endorse a >50% contribution to global warming from humans?
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Tom Curtis at 00:29 AM on 21 May 20132013 SkS Weekly Digest #20
FYI, urgent private matters are likely to keep me away from climate discussion for the next month or so. I wish you all good fortune, and look forward to when I am able to once again rejoin the discussion.
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Bob Lacatena at 22:25 PM on 20 May 20132013 SkS News Bulletin #12: The Consensus Project
Tom,
As far as I know, this is common knowledge (and common sense). No one expects (or wants) the President of the United States to spend his time tweeting.
At the same time, there is no question that his twitter account follows guidelines and an agenda laid out by himself and his staff, and is under his name, so it is representative of what he would tweet if he had the time. It is for all intents and purposes from him.
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Tom Curtis at 21:20 PM on 20 May 20132013 SkS News Bulletin #12: The Consensus Project
And speaking of blunder's (or errors, anyway), apparently most tweets @BarackObama are not by the President himself. In the profile it says:
"Barack Obama Verified account
@BarackObama
This account is run by Organizing for Action staff. Tweets from the President are signed -bo.Washington, DC · http://www.barackobama.com"
The Tweet above is not so signed, and so originated with Obama's staff rather than with the President himself.
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Tom Curtis at 21:16 PM on 20 May 20132013 SkS News Bulletin #12: The Consensus Project
CBDunkerson @18, that is indeed the point. I think there is a legitimate further argument. "An expert is someone who knows some of the worst mistakes that can be made in his subject and how to avoid them." (Werner Heisenberg) When 97% of the world's experts on a subject agree, you can therefore be very sure that it isn't because they are making blunder. They may be wrong, but the facts that show them to be wrong will either be hard to come by, or require subtle reasoning to demonstrate. Put another way, when you have a broad concensus in a well developed field, it takes an Einstein to show that they are wrong.
Despite this, time after time deniers come up with arguments that AGW is not occurring, or will not be bad, etc, that assume the world's climate scientists have made absolutely trivial blunders. The arrogance of those claims continues to stun me. But anyway, given a 97% concensus, if somebody presents themselves saying they have made a trivial blunder it is quite appropriate to ask (and a valid implicit argument), "Which is more likely, that several thousand of the world's top scientists have made a trivial blunder, or that you have?"
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CBDunkerson at 20:51 PM on 20 May 20132013 SkS News Bulletin #12: The Consensus Project
william - The point of the study is not to argue, '97% of climate scientists agree, therefor it must be true'... but rather, '97% of climate scientists agree, therefor the claims of widespread scientific disagreement are clearly false'.
In short, this study should be a knockout blow to climate myth number 4 in the list at the upper left of the page. Though I expect the usual deniers to keep spreading that myth, hopefully now they will be called on it.
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Tom Curtis at 20:44 PM on 20 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
barry @146, the criticism that several of the abstracts were publicly discussed on the SkS forum, contrary to the statement in the paper that ratings were "independent" at the first stage, is correct. I do not have a hard figure on how many were discussed, but it is more than 10 and likely less than 20. Of those discussed, many (possibly most) were simply posted with a note that it was odd, or interesting and with no discussion of the appropriate classification or rating. Others were posted with the posters own classification but no further discussion.
These instances do contradict the claim in the paper that, "Each abstract was categorized by two independent, anonymized raters." With just 10 to 20 instances, ie, less than 0.2% of instances, to say the claim that the raters were not independent would be misleading. Never-the-less it could be argued that these abstracts should be excluded from the analysis. Of course, from among those I have examined, the were either excluded as "not climate related", rated as neutral or, in one instance, rated as rejecting the consensus. Consequently I don't expect any demands in that direction.
Given the very low number of abstracts involved and the very high number of abstracts surveyed, there is no question of these instances having distorted the result. Indeed, it is not even known that it would have changed the rating of any given paper so it is entirely possible that it would have no effect on the result.
Curiously, the only instance that contained extensive discussion the appropriate rating, and the instance used as an example by Brandon Shollenberger at Lucia's was Cool dudes: The denial of climate change among conservative white males in the United States. What he does not mention was that it was rated as neutral and excluded at not climate related. Given that it is an analysis of the effects of gender, race and politics (conservative white males) on acceptance of climate change denial, who could disagree? Of course, it takes all of 5 seconds on the SkS concensus project searchable database to find out that information - far too much time to be expected to spend on research before you start slinging accusations /sarc
In fact, the only person at Lucia's to have mounted criticisms of any seriousness is Lucia herself. I think she is wrong either on the substance of significance of her criticisms but at least they are criticisms worthy of consideration. The rest of the criticisms are completely inconsequential, absurd, or in at least one case outright dishonest.
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yocta at 19:54 PM on 20 May 2013It's too hard
Tom Curtis @27:
Thanks for the reply.A lot to think about. I would agree that looking more into the numbers of things is important, however the 77.7 square metres per week I feel is quite significant. Also that will only account for 2tW. There would be another 13tW to go.
According to the International Energy Outlook [1] the future of energy has it growing by ~50% by the year 2035. Projected oil use increases. Projected fracking from natural gas reservoirs also increases.
More of a comment really, but I don't share your optimism that it would only cost 1% of the US GDP. There are so many countries with their own competing interests, and, if history shows Economy always beats the Environment. Coal usage [2] shows absolutely no sign of slowing down, especially in the developing world.
If the effects from Cook et al., (2013) recent study still shows from the usual crowds is denial, denial, denial. The often misquoted Daniel Botkin on how it will take a natural disaster or two to get people really talking, Results from the Yale Climate Change Communication Project [3] showing that a cold season is enough for people to think Climate Change is not happening, again reinforces this view.
World population and energy use per person I think will be the elephant in the room. I would agree that Bartlett's equation does exclude the Emissions Intensity. Thankyou for that.
I am still staggered by the level of denial I meet on any news article, blog, or YouTube video of people still not understanding anything.
This reads more of a rant than anything constructive. I wish I could share your optimism. Myself I work in the energy sector trying to green things (or at least light brown) them up but at times I feel like Sisyphus. If you or anyone could direct me to any readiing material that can show a more optimisic world view I would be very appreciative.
[1] http://www.eia.gov/forecasts/ieo/
[2] http://www.eia.gov/oiaf/aeo/tablebrowser/#release=IEO2011&subject=0-IEO2011&table=7-IEO2011®ion=0-0&cases=Reference-0504a_1630
[3] http://environment.yale.edu/climate-communication/article/Climate-Beliefs-April-2013
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Kevin C at 19:35 PM on 20 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Eli's just put up a cross comparison from his own smaller study here.
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scaddenp at 17:42 PM on 20 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Barry, the aim of the methodology is create an inscutable rating of the papers. It is not an investigation of bias - it aims to avoid it. Surely discussion and comparison of ratings and raters to produce a reliable rating of the papers is actually important to this.Deniers are in a tiz of John's surveys because they are not confident that their ratings would not show bias. However, this paper is actually about measuring the consensus.
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JasonB at 17:37 PM on 20 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Hard to believe that something so basic can stump them.
Indeed.
I think of the work leading up to the supporting/rejecting test as a filtering exercise, designed to weed out the irrelevant papers.
We start with the title of the paper: "Quantifying the consensus on anthropogenic global warming in the scientific literature"
That means that the first filter we are going to apply is one that will weed out everything that is not "the scientific literature". In this case, the ISI Web of Science was chosen to represent "the scientific literature".
This will include a lot of early papers that are not really relevant to modern scientific thinking, so the next filter is to limit the time period to 1991-2011.
This is still going to give an enormous quantity of literature to review, most of which will be irrelevant to the question at hand, so the next filter is to use the topics "global warming" and "global climate change". This should not affect the final result provided there is no systematic difference in the use of those keywords between papers that endorse the consensus and those that reject it.
Now the first three filters don't really require any manual effort to apply, but unfortunately there's no avoiding the next one — weeding out papers that are irrelevant to the question at hand but happen to use those keywords. That requires human involvement.
But the result of that final filtering step is a set of papers that actually does address the question and allows the degree of consensus to be quantified, just as the paper purported to do.
Now, they could report the percentage of papers that endorse the consensus and the percentage of papers that reject the consensus as percentages of various totals:
1. All papers that address the question at hand. (97.1% endorse, 1.9% reject.)
2. All papers that passed the keyword and date range filtering steps. (32.6% endorse, 0.7% reject.)
3. All scientific papers. (~0% endorse, ~0% reject.)
The first one is obviously relevant because it directly addresses the question at hand.
The second is also somewhat interesting, because we expect that as the science matures, fewer and fewer authors will feel the need to state a position on the subject because it will be conventional wisdom, and it's interesting to know how much effort the authors put in and to quantify the size of the work in the field.
The third is obviously useless.
Confusing the second with the first is, as you say, hard to believe.
Why stop at papers with those keywords? What is so special about a paper that fails to address the question that happens to use those keywords vs a paper that fails to address the question that happens not to? After all, the purpose of those keywords was simply to make the problem tractable by reducing the number of papers that need manual classification without, hopefully, affecting the final results. The percentages in #2 can be made as small as you like by adding even more irrelevant papers, but the percentages in #1 should be invariant provided the assumption holds that there is no systematic difference in the use of those keywords between papers that endorse the consensus and those that reject it.
Anybody who nevertheless chooses to use #2 but fails to report the "rejection" figure as 0.7% really has no excuse.
BTW, there is one filtering step that really does make a difference to the outcome, and that's the first one, but since that's the whole point of the paper I guess I'll let it slide. :-)
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JasonB at 16:43 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.
Papers that implied humans were having a minimal impact without saying so explicitly, or explicitly minimised or rejected the notion that humans are causing global warming, or explicitly stated that humans are causing less than half of global warming, were classified as 5, 6, and 7, respecitvely, so I think that the reporting you are objecting to actually reflects the findings correctly.
one must also be careful to note that a large proportion of the rated abstracts/papers were neutral.
Did you actually try the rating exercise yourself? If not, I suggest you do so, because then you'll see why they were "neutral" and what that really means. 50% of my sample were "neutral" according to the rules of the classification, but in every case it was purely because they were looking at impacts without addressing why global warming was occuring as it was outside the scope of their study. Indeed, the very first sentence of the introduction of one of my "neutral" papers (rated by reading the abstract in isolation) explicitly stated how much temperature was due to rise globally over the coming century based on greenhouse gas emissions and cited the IPCC as the reference!
For the purposes of this study it is fair to ignore neutral papers when quantifying the consensus, but it would be a mistake to assume that because they are neutral that is somehow evidence against the consensus. In fact, the reverse would be true — as the science matures, fewer and fewer papers would feel the need to mention "humans are causing global warming" because it's taken for granted that everyone accepts that, just as papers in the field of biology aren't going to be stating that they accept evolution unless they are explicitly about evolution.
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schmoepooh at 16:37 PM on 20 May 20132013 SkS News Bulletin #12: The Consensus Project
People who make a living dealing in untruths find it convenient to suppose truth is an unrealistic ideal.
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JasonB at 15:45 PM on 20 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Dr Tung,
It was not intended to be a criticism, but I might have pushed one of the hot buttons for some of you unknowingly. Could it be the word "under predict", which to me just means that the model warming is less than the observed warming. I did not attach any value judgement to it.
I think the issue is that we're used to statements like that being supported. There are many potential reasons why the models might under-predict the early 20th century warming but we'd like that to be established before moving on to the implications.
Your point about inter-model variability is a good one. One danger of combining different models with different systematic errors is that the systematic differences become part of the spread (i.e. it makes it harder to distinguish between internal variability, which is meant to model non-climactic "noise", and systematic differences between models).
If this is a genuine issue that you have identified then you should be able to answer "Yes" to my first question in my last comment — there is a test that would allow you to distinguish between the actual observations and any of the individual model realisations. If so, please present it, it would be really interesting to see.
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KK Tung at 15:39 PM on 20 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
In reply to Tom Curtis in post 61: your points are well taken. Assume the observation is perfect in my hypothetical argument. By "multidecadal internal variability" you could take it to mean "internal variability that in this multidecadal period in total gives rise to an additional warming"
I find it frustrating that I often get bogged down by words. I was surprised by so much nitpicking that distracts the discussion into a different direction. I guess I shouldn't have been surprised. After all this is Skeptical Science.
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JasonB at 15:31 PM on 20 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Dr Tung,
But we find the model ensemble mean to under predict the observed warming rate in the first half of the twentieth century.
You keep making this statement as if it is self-evidently meaningful so allow me to ask a very simple question:
If you plot the observed warming rate in the first half of the 20th century together with all of the model simulations, does it stand out? In other words, can you pick out which one is the observed warming without knowing in advance which line represents the observations and which lines represent the simulations?
My answer to that question would be "No", based on Figure 9.5 (a) from AR4, posted already by KR in #23 and reproduced here for convenience:
If the observed warming wasn't black then you wouldn't be able to distinguish it from any of the individual realisations of the climate models. Contrast this with Figure 9.5 (b) above — the behaviour of the black line clearly stands out from the individual realisations in the second half of the century and is even the most extreme realisation a few times in the first half.
A more sophisticated test would be: "What is the range of trends for the individual realisations for the first half of the 20th century? Is there a statistically significant difference between the observed trend and that range?"
All of this is even before considering Tom Curtis' points, which are also valid, and the fact that Kevin C's simple 2-box model does a remarkable job of matching the observations with just the forced response and ENSO.
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KK Tung at 15:28 PM on 20 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Continue with my post 60: I hope post 60 can clear up the confusion and we can get back to the scientific issue at hand.
Back to CMIP3 models. I mentioned that the intermodel spread is rather large. It is difficult to conclude anything concrete with the intermodel spread. For political reasons less developed models from some countries were included. Some models have unrealistic internal variability. I know of one model with a perfectly periodic ENSO with exactly two year period that is also quite large in amplitude. Another model with a huge decadal variability of 0.4 C in the global mean temperature. In the 40 years the early twentieth century warming also warmed by 0.4C in the observed global mean temperature. When all of the model results are averaged in the all model ensemble mean, only 0.2 C warming is found during this period. There should have enough members in the all-model ensemble mean to eliminate the model internal variability, but we are not sure if that ensemble mean gives the correct forced solution. We could pick a few models we know and trust and look at them. Although there were not enough ensemble members available (usually 5 were done), we suspect that they were good enough to reveal approximately the forced response. During the first half of the 20th century, the warming generally were rather flat in these models that we examined. This is also a period during which the AMO was in its warm phase and can contribute 0.3 C to the warming. This was my thought process. It was not intended to be a criticism, but I might have pushed one of the hot buttons for some of you unknowingly. Could it be the word "under predict", which to me just means that the model warming is less than the observed warming. I did not attach any value judgement to it.
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