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yocta at 10:44 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Is this an appropriate analogy?
Lets suppose 100 medical science papers were searched for the words lung cancer?
Now if 100 abstracts were returned and (Using Kevin C's approach):
Address the question, smoking is a cause of lung cancer (32.6%)
Address the question, don't know the answer (0.4%)
Address the question, smoking not a cause of lung cancer (0.7%)
Don't address the question (66.4%)It would be silly based on these responses to even argue that 66% of scientists consider smoking not a cause of lung cancer.
(obviously there are other causes for lung cancer...but this was a back of an envelope kind of thing)
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KK Tung at 10:19 AM on 18 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years?
I am glad that it (inserting a figure) works this time!
This figure was done following Bart Verheggen's prescription of removing the usual solar, ENSO and volcano influences, but not the AMO or anthropogenic influence, because we don't know what the latter is.
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KK Tung at 10:16 AM on 18 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years?
Could someone tell me how to insert a figure into the comment the correct way? Thanks.
Also in reply to post 53: "The Lean and Rind analyses would make me think there would not be a substial influence of such cyclical behavior, but that's worth investigating with newer data". This was done with the old and also with the new data. See my post above. The point is: if you just look at the anthropogenic response from the assumed regressor, it would show accelerated warming after 1978. But the residue has a negative trend after 1978. When that negative trend is added back to the regressed response, the combination becomes more linear.
Here is another try for post 54 with a pdf figure:
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nealjking at 10:06 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Otiose,
Science is conducted by human beings, and is heir to the weaknesses of human beings.
Nonetheless, science has managed to overcome the confines of Galilean/Newtonian mechanics to understand relativity; the confines of "realism" to create quantum mechanics; and many other discoveries and inventions that were originally undreamt of.
The way science is done in climate studies, including control of access to publication of articles, is not different from the way it is done in other sciences.
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nealjking at 10:00 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
#89: grindupBaker at 07:40 AM on 18 May, 2013
A very good collection of papers on the topic is:
The Warming Papers: The Scientific Foundation for the Climate Change Forecast,
by David Archer and Raymond Pierrehumbert
It's not a cheap book; you might be able to find it at a local library.
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Dikran Marsupial at 09:52 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
otiose, government funding is spent on plenty of climate skeptics, for instance Roy Spencer, who apparently gets all his funding from government sources and Henrik Svensmark, who according to his book "the Chilling Stars" appears to have much less trouble getting government funds than most. Or the CLOUD project at CERN, 12 million euro is a lot of money. Just because skeptics say they can't get funding, or get their papers published, doesn't mean it is actually true.
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Otiose at 09:45 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Nice study. However, there are several factors that are not included in the scope of the study that undermine its target conclusion and these relate to what's not in the papers reviewd.
The funding for climate science has been channeled by many governments since at least the early 90's (especially true in Europe) specifically towards those scientists concerned about climate i.e. probably already predisposed towards concluding that humans were the cause if not the primary cause. That would bias the pool of potential papers as scientists not interested global warming itself or of a contrary opinion would not get the funding. Other scientists in order to get funding would be incentivized (need to eat, career advancement, desire to support families, etc.) to slant their work in the preferred direction.
Moreover we know from the email release that there were important journals in the field that simply refused to accept the work of known skeptics. Another factor tending to bias the pool.
And then the peer groups selected to review submitted papers tended to be skeptical (and not in an ironic sense) toward the qualifiations and work product of any scientist who didn't lean heavily towards the conclusion that humans were the primary cause of global warming (or indeed that it exists today and did in the past). Yet another hurdle for contrary concluding papers to get through.
Finally, for a few decades it's been common knowledge that any scientist who was known to be contrary to the emerging "consensus" had something less than a snowball's chance in hell of getting hired into the faculty of a major university.
So while the study sounds good there are several factors that undermine the touted conclusion. There were at least the above factors that would tend to encourage the consensus that emerged within the published papers that had nothing to do with the underlying validity of the science or what was or was not going on within climate and had everything to do with subtle and not so subtle intimidation of one form or another targeted towards those in the field who did not conform to the party line.
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Riduna at 09:15 AM on 18 May 2013The last time carbon dioxide concentrations were around 400ppm: a snapshot from Arctic Siberia
John Mason – What an excellent article. Just how high was Pliocene and early Pleistocene average sea level compared the present?
Tom Curtis @13 expresses an optimistic view that by curbing CO2 emissions to 450 ppm (can we?) average global surface temperature will not exceed 2ºC above the pre-industrial by 2100.
I wish!
It might be, if we ignore the effects of slow feedbacks such as accelerating loss of albedo and permafrost, carbon emissions in the Arctic and increasing ocean heat content. Unfortunately we can not. Nor can we assume that CO2 concentration will not exceed 450 ppm by 2050, let alone 2100.
In the absence of enforceable national emissions targets it seems unlikely, unless there are remarkable technological developments enabling affordable carbon capture and sequestration or cheaper electricity generation from renewable sources.
Present rates of anthropogenic CO2 emissions are over 2 ppm/annum and accelerating making it very likely that concentration of 450 ppm will be reached by 2040. Emissions will continue thereafter reaching 560 ppm by 2100, resulting in average global surface temperature of around 3ºC.
It seems likely that anthropogenic emissions and those caused by slow feedbacks will result in considerably more than 560 ppm CO2 equivelant by 2100 with average global surface temperature of around 4ºC above the pre-industrial.
We should all hope that science and technology will reduce this possibility over the next 50 years. I believe they will. However there is shrinkingly little possibility that average global surface temperature of over 3ºC above the pre-industrial can be avoided this century.
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adelady at 08:41 AM on 18 May 2013Measure the climate consensus yourself with our Interactive Rating System
Hard to categorise? Yup. I studiously kept on checking that I was doing the ratings correctly. And worried that I was getting it wrong in some way or another. Now I've checked mine against the project and every single ratings number I gave was the same as theirs.
But the categories? Not hopelessly jumbled, but distinctly unwonderful in places. I'll now be using my previous scores to inform my future categorisations.
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Dikran Marsupial at 08:39 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
grindupBaker @89 In addition to Tom's answer, generally if you send an email to the corresponding author of the paper, they will be only too happy to send you a pre-print of the paper (if it isn't already self-archived on-line somewhere). This is something that most journals are comfortable with (there is an on-line database somewhere listing the practices of most journals); indeed in the old days when you published a paper in a journal they would send you a couple of dozen free paper copies of your masterpiece (as it appears in the journal) for just that purpose (which then sit in your filing cabinet for several years untill your office becomes terminally full and you put them in the recycling bin).
There is nothing that us scientists like more than to hear that someone actually wants to read our papers! ;o)
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KK Tung at 08:13 AM on 18 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years?
In reply to posts 52 and 53 by Bart Verheggen: Your suggestions are fair. Our work were actually following ideas similar to your suggestions.
(1) We did not assume linearity for anthropogenic forcing. In the post we used a number of nonlinear anthropogenic indices.
(2) "Another approach would be to rather than using a questionnnable (see my previous commment) estimate of the AMO as a predictor in the regression analysis, see if there is a AMO-type (or other cyclical) signal is left over in the adjkusted temperature, after having corrected for the better known influences (solar, ENSO, volcanic, anthropogenic)." This was what we did in Zhou and Tung (2013). After we accounted for your suggested better known influences, the blue line in the figure was what remains, and it shows an AMO like signal.
[image snipped]
Moderator Response:[Dikran Marsupial] Sorry, I had to delete the image as it was causing formatting problems (at least under Firefox). Please try using a URL to a copy of the image that already exists on-line.
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Tom Curtis at 08:07 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
I don't think people are giving Herhund's arguments the seriousness they deserve. Afterall, consider one of the "neutral" papers I rated yesterday. Surely it is obvious that if a paper on "Environmental Assessment Of Supercritical Water Oxidation And Other Sewage Sludge Handling Options" does not explicitly state that "Humans have caused more than 50% of global warming since 1950" then the authors must disagree with that proposition. Isn't it? Afterall, that is just part of the general maxim that "Silence is disagreement"
/sarc
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Tom Curtis at 08:00 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
grindupBaker @89, subscriptions to most scientific journals includes access to articles from prior issues on the web. Articles from periods prior to when web publication became common may not be included in this.
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Tom Curtis at 07:53 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
william @90, I'll bite. Just how often has the past consensus of a mature science (one with more than a million man hours of scientific research behind it) been wrong? I can only think of one instance (continental drift) and in that instance the alternative theory presented at the time was also wrong, but when a correct theory was presented it was rapidly adopted as the consensus view.
People often forget how few were the number of scientists before the twentieth century, and how limited their resources. For example, science courses (other than Mathematics) did not even exist at Cambridge University until 1851. With the small number of scientists in the past, and their limited resources, it took time to falsify promising theories. Further, most "examples" of theories that have been overturned are like Newton's theory of motion in which the overturning theory predicts the same results as the original theory withing the range of conditions in which the first theory was tested. Even today, NASA uses Newtonian theories of motion to work out the orbits of satellites and interplanetary missions.
In fact, if the history of science teaches us anything, it teaches us that once a scientific theory commands a consensus with in an area of detailed observation, any future theory will predict the same observational consequences within the resolution of current observations. So unless the CO2 concentration exceeds that of Venus, or drops near zero (the range of current observations), the history of science suggests that if any theory replaces AGW it also will predict a CO2/temperature linkage.
Further, people often forget (if they ever knew) the real bite of the argument from scientific consensus. The scientists are the experts, where an expert is somebody who knows enough about a subject not to make dunderhead mistakes. If there is a scientific consensus, then that means the vast majority of people who will not make silly mistakes accept the theory (and the exceptions all have known, strong ideological agendas, like Fred Singer who turned down a job offer from the White House because it would not allow him enough influence on policy). That means it is extraordinarilly unlikely that there is any obvious error in the theory of AGW, while obvious errors in alternative theories abound.
However, this is beside the point. Climate change deniers frequently argue that there is no scientific consensus on climate change. The need to. If they do not accept that false belief they are forced to explain why so many people who know far more about the evidence then they do, and typically are far more intelligent, accept a theory while they reject it. This article, and the paper it reports on merely shows that frequent denier claim. The frenzy with which the paper has been attacked by climate change deniers shows they know what is at stake. If this paper becomes well known and accepted, their most powerfull (and falacious) argument - that there is no scientific concensus so therefore the evidence must not be conclusive- is false.
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grindupBaker at 07:40 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
I might find some hours to study next winter if I don't lose interest. Can anybody inform how I get 100 or so of the most informative prior peer-reviewed papers without paying $32 each ? Does a magazine subscription somewhere include some back issues ?
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Dikran Marsupial at 07:35 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
William the existence of a concensus is not scientific evidence of anthropogenic climate change (and nobody is claiming it is), the consensus is a result of the scientific evidence of anthropogenic climate change.
AFAICS the purpose of the study is to demonstrate the disconect between the public/political perception of the science of climate change and the scientific perception of the science of climate change. The scientists are able to weigh the evidence for themselves, but what about the general public? Who should they trust? I would suggest that mainstream scientific opinion is the most rational option (as the "outliers" are in fact very rare*), and this paper communicates very clearly where mainstream scientific opinion lies, and how few papers there are that actually challenge the mainstream view.
*It is true that occasionally there is a Gallileo who overturns the scientific orthodoxy, but there are many more scientists you never get to hear of who challenge the scientific mainstream and are simply mistaken. Gallileos are vanishingly rare in the population of scientists, academics that have merely "gone emeritus" are not. If someone thinks the scientific mainstream is wrong on AGW, the odds are not in their favour. I wish they were.
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John Hartz at 07:18 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Herrhund:
Your recent posts are in violation of the following part of the SkS Comments Policy. As such, they have been deleted.
Comments should avoid excessive repetition. Discussions which circle back on themselves and involve endless repetition of points already discussed do not help clarify relevant points. They are merely tiresome to participants and a barrier to readers. If moderators believe you are being excessively repetitive, they will advise you as such, and any further repetition will be treated as being off topic.
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Jim Eager at 07:14 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Herrhund wrote: "there are other theories"
Except that there are no other theories.
There are several hypotheses, most of which have already been disproven, such as "it's the sun," or shown to be insignificant, such as cosmic rays, but none have risen to the level of being a cohesive theory supported by the full body of evidence.
None. Zip. Nada.
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Rob Honeycutt at 07:02 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
herrhund... Would you prefer that we merely use the phrase "0.7% of the published research found to reject anthropogenic climate change?"
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Kevin C at 06:44 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
herrhund:
How many of the 66,4% address the topic and expressed no position on AGW?
None. See table 3 in the paper. The papers in the 66.4% are in that class because they didn't address the question. There are 4 categories in table 3:
- Address the question, humans causing most of GW (32.6%)
- Address the question, don't know the answer (0.4%)
- Address the question, humans not causing most of GW (0.7%)
- Don't address the question (66.4%)
Among papers which addressed the question the consusus view is 97%. You can't classify the consensus among papers which don't address the question because they don't address the question.
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william5331 at 06:34 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
I have not doubt that climate change is happening and none that we are causing it but consenses is a pretty weak argument for anything scientific considering how often in the past the outlier has been correct and the crowd, wrong. Better we just look at the overwhelming evidence in it's own right rather than using an argument that is of such questionable value.
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John Hartz at 06:10 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Here's the best one sentence description of the paper that I have come across.
An analysis of 4,000 abstracts of peer-reviewed articles on the topic of global warming and climate change has revealed an overwhelming consensus among climate scientists that recent warming is human-caused.
Source: There Is Scientific Consensus On Anthropogenic Climate Change Among Climate Scientists
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Kevin C at 05:59 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Yes exactly.
Just having 'global warming' in the title does not mean a paper addresses the question of whether human activity has been the dominant cause of recent warming. Here are some examples:
1. A paper on measuring the warming signal might say nothing about the cause.
2. A paper looking at the impact of global warming on animal habitats may say nothing about rate or cause.
3. A paper on adapting societies to deal with global warming does not address the issue either.
You'll find thousands like this. All of these are classified as 'no postion' because they don't address the question. These are distinct from papers which try to address the question and are undecided on the answer.
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Kevin C at 05:25 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
herrhund: If you go to the TCP site and rate a few papers yourself, you will find the answer to your question.
The survey is trying to assess the consensus on whether humans have caused the bulk of recent warming. The fact that a paper takes 'no position' does not imply that the the authors failed to reach a conclusion on this question. The majority of the papers involved simply didn't address the question. Go and read some of the abstracts and you will see for yourself.
If you want to know what proportion of papers accept, reject or are undecided on a question, you have to count papers which address that question. Throwing in a load of papers which do not address the question in order to distort the statistics would be nonsensical.
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BWTrainer at 04:48 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
@83 - Most of the papers were not attempting to come to such a conclusion, so their "failure" to do so is not surprising.
Anyone who reads the entirety of the sutdy available for free, or this article, or one of several other articles about the study, will be left with no confusion as to the conclusions.
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VictorVenema at 04:46 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
I presume you will have to do this type of study every year as soon people will have forgotten it again and will again think that scientists think the same as their libertarian neighbour.
For a follow-up study it may be nice to study abstracts from climate journals. That way you are sure the studied sample is not biased by first searching for key words. I expect no difference, but it would be nice to be sure. I would advocate to ask an experienced bibliographical researcher to organize the study.
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herrhund at 04:26 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
"A new survey of over 12,000 peer-reviewed climate science papers by our citizen science team at Skeptical Science has found a 97% consensus in the peer-reviewed literature that humans are causing global warming"
This is a false statement.
66,4% of the abstracts expressed NO POSITION on AGW, wich means just 32,6% endorsed AGW and then out of that 32,6% - 97,1% come to the conclusion that the climate is human driven.
So just, 32% of 11 000 implicate AGW
Which also means that most of the papers did not come to the conclusion on AGW
"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. Among abstracts expressing a position on AGW, 97.1% endorsed the consensus position that humans are causing global warming"Moderator Response:[JH] You have stated your opinion. Doing so once is sufficient. Repeating this mantra is sloganeering. Please cease and desist.
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DSL at 03:17 AM on 18 May 2013It hasn't warmed since 1998
To further Dikran's point, consider the trend of 1992-2007. Using Had4, the trend is 0.3C per decade. That's approaching double the expected rate of warming. According to your logic, climate scientists should have declared that they had seriously underestimated the rate of warming. No. It's a short-term trend. And it's a cherry-pick. And it covers half of your 16-year period. You can try to reconcile all that, or you could actually engage a critical thinking process and try to understand the forces at work that create the state of the surface temp -- like scientists do.
One more thing, Warren: when you say "no warming" you immediately reveal yourself to be ignorant about the science. You complained about the accuracy of the survey titling. Now you want a free pass for using an insignificant portion of the thermal capacity of the climate system (the troposphere) to represent the whole shebang. Ignoring OHC is deceptive . . . or ignorant. Your response will determine my choice.
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jdixon1980 at 03:16 AM on 18 May 2013Measure the climate consensus yourself with our Interactive Rating System
Love it, love the ongoing improvements.
A suggestion - how about a category for articles relating to the effects of factors other than GHG emissions on climate? I came across an article on clouds that was hard to categorize.
Another abstract was an environmental impact study of engineered water recirculation for fish farming, and one of the impacts was "GWP (global warming potential)." I wasn't sure if it was safe to assume that the GWP was due to GHG emissions related to generating the mechanical power to recirculate the water, or if it could be something else like albedo or CO2 uptake effects of tinkering with bodies of water and/or land. (I suppose if it were CO2 uptake effects, that would be an implicit endorsement of AGW, because if CO2 uptake affects climate, than so do emissions.)
Another possible article topic that could be hard to categorize would be climate effects of sulfate/aerosol emissions (as by-products as opposed to deliberate geoengineering, which would fit nicely in mitigation).
I suppose the best place for this type of article right now is "methods," in the sense of the category description "basic climate science not included in the other categories." But using "methods" as a catch-all category in this manner might obscure the statistics about articles that really get into the nitty-gritty details of data selection, gathering, and analysis.
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Rob Honeycutt at 02:08 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Warren... Think of it this way. The paper set out to better understand the level of consensus on AGW in the published literature. Right? We rated 12,000 peer reviewed papers. From that research we found a 97% consensus that humans are responsible for global warming.
That is what the paper is about. That is what the research found.
The alternative presentation you could make is: The paper set out to better understand the level of consensus on AGW in the published literature. We rated 12,000 papers and found that 32% accept it. 66% show no position. And 0.7% reject AGW.
Take your pick.
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Dikran Marsupial at 02:02 AM on 18 May 2013It hasn't warmed since 1998
Warren, well worth reading the Guardian's reporting on James Hansen's BBC R4 comments this mornng (here), in particular:
Prof Hansen, speaking to BBC Radio 4's Today programme, rejected both arguments. "In the last decade it has warmed only a tenth of a degree compared to two-tenths of a degree in the preceeding decade, but that's just natural variability. There is no reason to be surprised by that at all," he said. "If you look over a 30-40 year period the expected warming is two-tenths of a degree per decade, but that doesn't mean each decade is going to warm two-tenths of a degree: there is too much natural variability."
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KR at 01:55 AM on 18 May 2013It hasn't warmed since 1998
Warren Hindmarsh - I've discussed this particular topic with Werner Brozek at some length, for example at Spencers blog. You, unfortunately, appear to have some of the same misconceptions regarding statistical significance - it's possible to cherry-pick an interval that shows any conclusion you wish, as long as you avoid using all of the data. But short periods are not statistically significant, there is insufficient data to make a claim one way or another.
As I have mentioned before on these threads:
For any of the instrumental series, over any time span ending in the present:
- There is no period where warming is invalidated, against a null hypothesis of no warming.
- Against a null hypothesis of the long term warming trend, there is no period where a "no warming" hypothesis is validated. None.
- Over any period with enough data to show statistical significance, that data shows a statistically significant warming trend.
Claims otherwise, such as your repetitions of 'skeptics' elsewhere, are demonstrably wrong.
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Dikran Marsupial at 01:12 AM on 18 May 2013It hasn't warmed since 1998
Warren, firstly your posts on SkS have demonstrated an argumentative rhetorical tone. This is not conducive to discussion of science and is likely to irritate the other participants in the discussion, which reflects more badly on you than on anyone else. Please give it a rest.
So "What is wrong with the graph?"
(i) It is an example of cherry picking start and end dates. If you have a time series with an upward trend that is small in comparison to the magnitude of the noise, then it isn't surprising that you can choose start and end points where the noise temporarily masks the trend. However that doesn't mean the trend has gone away. This can be easily demonstrated by constructing a synthetic time series with an upward trend (so you know it is there by construction) and observing that you can still cherry pick periods where this trend is masked.
(ii) Trends are not measured by noting the difference in temperature at the start point and the endpoint as this is to sensitive to the noise to have any statistical meaning. Instead scientists use least-squares linear trends, often adjusted to take account of the autocorrelation.
(iii) The anlaysis makes no mention of statistical significance, nor of the statistical power of the test (which is very important if you want to claim that there has been no warming since 1998, I'd be happy to explain this in more detail when you respond to my post).
Moderator Response:[JH] I have deleted a number of Warren Hindmarsh's comments because they were off topic and/or slogannering. He definitely needs to loose the snarky tone. He also should read and adhere to the SkS Comments Policy.
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jdixon1980 at 00:57 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Will there be a follow-up article comparing the results of the public survey of abstracts to those of the SkS team and the self-rating authors?
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Robert Murphy at 00:57 AM on 18 May 2013It hasn't warmed since 1998
"What's wrong with this graph"?
It's mislabeled. WATTS and company can't add - that's 15 years, not 16. It's also been shifted - the real data on that is from August 1997 to August 2012, not the beginning of 1997 and the end of 2012. Also, the values have been altered. The first one should be less than .5*C and the last higher. It's been fudged, in other words."The Hadley Centre/CRU records show no warming for 18 years (v.3"
False. v.3 shows about .14*C of warming over that period globally.
"or 19 years (v.4),"
Even more false. The trend is bigger with v.4 - about .17*C of warming over the last 18 years and about .2*C over the last 19.
"and the RSS satellite dataset shows no warming for 23 years"Spectacularly incorrect. RSS shows about .28*C of warming over the last 23 years.
"h/t to Werner Brozek for determining these values"Hat tip for feeding you false data? Seriously? Where's your skepticism?
"temps have been rising slowly since the middle ages"So, you're a LIA denier too?
"sorry gotta go catch ya later"
Ah, hit and run. Next time, why not come back with correct info?
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CBDunkerson at 00:35 AM on 18 May 2013It hasn't warmed since 1998
Warren Hindmarsh wrote: "what is wrong with this graph"
Read up on 'cherry picking'... that is, deliberately choosing a time period which shows the result you want despite the fact that longer and/or shorter time periods show results contradicting your claim.
Also: "temps have been rising slowly since the middle ages"
Not according to any historical temperature study I am aware of. Indeed, temperatures were slowly falling for thousands of years, including both before and after the 'middle ages', until the modern greenhouse warming surge.
Finally: "but for the last 17yrs or so [temps] have stablized"
Again, 'cherry picking'... not only of the time period, but also which temps. Ocean temps have certainly not 'stabilized' over the past 17 years.
You obviously didn't even bother to read the post above. Maybe try that before making arguments which it has already disproved.
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CBDunkerson at 00:27 AM on 18 May 2013A Detailed Look at Renewable Baseload Energy
JvD, no SkS is not here creating a false impression. As you concede, it is possible to achieve global 100% renewable energy... with current technology. It would just be very expensive. If you read the post above you will see that it does not advocate 100% renewable power with current technology, but rather "within the next few decades" and "by 2020 or 2030". Ergo, no it is not ignoring the cost factors.
As I said upthread, I think there will be a transition period over the next few decades where natural gas and existing nuclear play a role. After that the buildout of the grid and storage combined with falling costs will lead to 100% renewables.
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Tom Curtis at 00:21 AM on 18 May 2013It hasn't warmed since 1998
A third question:
Isn't it misleading to say that a period with a positive tempertature trend (ie, temperatures are rising) shows no warming?
Please note that "no warming" does not mean the same thing as "the warming is not statistically significant".
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Warren Hindmarsh at 00:18 AM on 18 May 2013It hasn't warmed since 1998
sorry Dipal have to go right now
The graph is from
The Hadley Centre/CRU records show no warming for 18 years (v.3) or 19 years (v.4), and the RSS satellite dataset shows no warming for 23 years (h/t to Werner Brozek for determining these values).
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Tom Curtis at 00:18 AM on 18 May 2013It hasn't warmed since 1998
Warren Hindmarsh, two questions:
Did temperature rise or stand still over the course of the twentieth century?
If the warming rate over a given period is greater than in a period over which temperatures are known to rise, is it correct to say that temperatures are not rising?
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Tom Curtis at 00:15 AM on 18 May 2013Measure the climate consensus yourself with our Interactive Rating System
Alexandre @3, I had the same problem but fixed it by reducing the zoom back to 100%. You may need to go a little lower.
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Alexandre at 00:13 AM on 18 May 2013Measure the climate consensus yourself with our Interactive Rating System
I had some trouble using it. When I moused over the 4th or 5th paper title, the abstract would appear so far up in the page that it did not appear in my screen.
I use Google Chrome 26.0.1410.64 m
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Warren Hindmarsh at 00:12 AM on 18 May 2013It hasn't warmed since 1998
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adelady at 00:09 AM on 18 May 2013Measure the climate consensus yourself with our Interactive Rating System
Oh my.
That's a terrible idea. I could get addicted to such a "game". (I find myself having to do _this_ lot of ratings so I can move to the next page just to see what the next interesting/ odd/ peculiar/ fascinating assortment of papers is going to be. The occasional downright weird item is just the cherry on the sundae.)
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Warren Hindmarsh at 00:06 AM on 18 May 2013It hasn't warmed since 1998
Hi dikran
where is the global warming :)
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Tom Curtis at 00:05 AM on 18 May 2013A Detailed Look at Renewable Baseload Energy
JvD @417, SkS is most definitely not being misleading on this issue, a point you have already tacitly acknowledged @407 when you wrote:
"Yes renewables can be used. But the difficulty is great."
You are not disputing a matter of technical feasibility, but only of economic cost. It may be true that the economic cost of an all renewables energy economy is to great to maintain continued economic growth, but it is not so high that such a conversion would bring down our civilization. Ergo it is even economically feasible to have a global renewable energy only economy. Beyond that I don't care provided that any nuclear power satisfies the conditions I specified above, and that renewables are a significant portion of any energy mix.
Finally, I do not agree that a full renewable economy can only be achieved with "extreme difficulty". Assuming that to be the case depends on assuming an technical difficulties with nuclear power will be quickly and cheaply resolved, while any technical difficulties with renewables are intractable. I don't believe in begging the question in so blatant a manner.
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K.a.r.S.t.e.N at 00:04 AM on 18 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
KK Tung @10:
I am referring to forcing from tropospheric (anthropogenic) and stratospheric (volcanic) aerosols likewise. They have an impact on both, the AMOC and the AMO. Sure, the response of the AMOC to external forcing is slower and hence harder to identify, but neither AMOC nor AMO are independent of it. I agree that the AMO is influenced by the AMOC (how can it not). The exact linkage is still under debate. However, I strongly disagree with your reply to Kevin C in post 8 and your notion that a volcanic impact on the AMO is unlikely. Let me try to convince you.
In your paper, you wrote: “The 20-y small dip in temperature near 1810 coincides with the solar Dalton Minimum, but is probably caused by a negative excursion of the AMO. The rising AMO cycle in the first half of the 19th century produced a warming, despite the eruption of Tambora (1815), the largest in the past four centuries.”
The problem is that we have a strong volcanic eruption in 1809 (unknown tropical eruption; see Cole-Dai et al. 2009 or Arfeuille et al. 2013), followed by the 1815 Tambora eruption (strongest eruption in the last centuries). Hence I have no doubt whatsoever as to what the reason of the negative AMO excursion is. It’s entirely attributable to these two strong eruptions. The surface air temperature over the Atlantic-Arctic boundary in your Fig.3C perfectly matches the timing of these eruptions. If we go on to the 1830s, we see the next dip which perfectly matches with the Babuyan Claro eruption (1831) and the next very strong eruption at Cosiguina in 1835. The dip around 1860 is stronger than one would expect from the amplitude of the corresponding eruption recorded in 1861, only to have a clear signal for the Krakatau eruption in 1883 again. Note that the exact magnitude of the volcanic forcing differs between different estimates. I plotted the older dust veil index (DVI) and the newer ice core index (ICI) from Crowley and Unterman 2012 for the time period 1750-2000 in order to illustrate my point.
Moreover, I consider it very likely that volcanic eruptions do have a measurable effect also on the AMOC. Gleckler et al. 2006 and Stenchikov et al. 2009 demonstrate that a persistent deep ocean signal emerges after strong volcanic eruptions. Therefore, most of the time the climate system is not in an equilibrium state as it takes several centuries to get rid of any remaining signal from volcanic eruptions. As soon as there is a lull in volcanic activity, the climate system warms in order to restore equilibrium. I don’t know how strong this warming signal is, but it definitely plays a role in post-volcanic periods such as that between 1910-1940. I agree with Tom Curtis (post 40), that this period saw some additional warming in the North Atlantic region due to increasing black carbon forcing (while anthropogenic sulfate forcing was barely rising during that very time). The external forcing impact on the AMOC is also widely discussed in the literature, with numerous suggestions as to what mechanisms could be at play. I would like to point at a very recent paper by Menary et al. 2013 or another one by Iwi et al. 2012. It goes without saying that undoubtedly internal AMOC variability exists undoubtedly. The review paper by Kuhlbrodt et al. 2007 gave a good overview.
Similar to what Kevin C did (see post 21), I recently developed my own two-box EBM model which accounts for volcanic eruptions at two time-scales: A fast surface temperature response which more or less coincides with the stratospheric AOD evolution, and a slow response which accounts for the deep-ocean signal as shown for the Tambora and the Pinatubo eruptions in Stenchikov et al. 2009. In addition, instead of using the GISS forcing (which I personally consider not very accurate regarding the tropospheric aerosol forcing) I used the forcing time series for sulfate and black carbon aerosols presented in Skeie et al. 2011. The resulting forcing function (nudged towards NH conditions) for the 1750-2010 period looks like this (I can provide more details upon request):
Not only are the volcanic spikes easy to identify, but also becomes their long-term effect noticeable. I am not claiming that this is the real volcanic fingerprint which we find in the observations, but it indicates where we might have to look for a forced disturbance in the thermohaline circulation, may it be the AMOC or ENSO/PDO. Let’s compare the forcing function with the NH instrumental observations and reconstructions:
Note that the temperature response in Europe as represented by the Berkeley Best data and Baur temperature series (both are comparable with the AMO temperature trends) is not always in phase with the rest of the NH. In fact, there is reason to think that the NAO response to volcanic eruptions is preferably positive. Fischer et al. 2007 have a good discussion on that. Assuming that the NAO and the AMO mutually influence each other, stochastic multi-annual or decadal variations as a result are all but surprising. Even in the absence of NAO-like atmospheric variability, Deser et al. 2010 brilliantly illustrate how white noise from pure random atmospheric heat flux variations turns into (oceanic) red noise. The time scale of the resulting SST fluctuations depends on the ocean mixed-layer height. It is interesting to note that the mixed-layer depth of the North Atlantic is comparably high, particularly in winter, which can easily explain the high standard deviation of its SSTs. The same is true for large portions of the North Pacific.
This brings me to DelSole et al. 2011, which you cited in your response. Likewise, they identified these very regions as most variable. However, I can’t see how the “projection” of the observed temperatures onto this pattern removes the problem of unreliable model forcing. As can be seen from my best-guess forcing assumption for the NH (which includes aerosol indirect effects, which most models omit altogether), the real forcing has likely been considerably more variable than assumed in your analysis as well as in their analysis (which is based in the forcings of the models used). This can also be illustrated by looking at the NH/SH inter-hemispheric temperature trend. Not only does it differ considerably, but also is the NH instrumental record strongly correlated with the anthropogenic sulfur emissions, which is almost certainly not a mystic coincidence.
Many other issues regarding the robustness of your results have been raised in the discussion already. I agree with Tom Curtis (post 11/15) on the magnitude of the AMO signal in the NH temperature variance, which I believe your method terribly deflates, as well as on the consistency and significance of the oscillation in the data (post 15/20), which I believe you have not demonstrated. Conservation of energy is another is another big problem (see e.g. KR in post 14) which you have so far failed to address properly.Finally, let me show you what happens if we extend the forcing time series back in time and keep comparing it with paleo-reconstructions. With a low-pass filter it looks like this:
From a NH point of view, the AMO plays a minor role as far as the temperature evolution is concerned. Not to mention global temperatures. The AMOC is important on longer time scales, typically in response to slow changes in external forcing. On shorter time-scales, AMOC changes can have strong regional impacts. The AMOC shutdown in the context of the 8.2ka event as the prime example for its response to strong fresh water pulses.
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Warren Hindmarsh at 00:03 AM on 18 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Tom I must admit I had difficulty making sense of the self rated section I can now see how the self rated respondents had a 62.7 % acknowledgement.
they contacted 8,500 authors 1,200 responded and reviewed 2,100 97% of which agreed with AGW
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Dikran Marsupial at 23:49 PM on 17 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
how about http://skepticalscience.com/global-warming-stopped-in-1998.htm?
It would be a good idea if you were to familiarise yourself with the existing discussion on that thread before posting, to avoid unnecessary repetition.
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Tom Curtis at 23:49 PM on 17 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
I find it amusing that Warren HIndmarsh, who is incorrectly arguing that the lead sentence of this article is misleading, offers as an alternative some word salad that contains simple falsehoods. Specifically, Of those papers that where self rated by the authors, 62.7% were rated as endorsing AGW by the authors, not the "around 30% of the self rated respondents" as claimed by HIndmarsh.
If that is not bad enough, he introduces the very misleading category of a "self rated respondents", thereby confusing the authors (ie, the respondents) with the papers that they rated.
Beyond that, I have only to add that we have already hashed out this non-issue. Whey then is Hindmarsh rehashing the issue without offering either new evidence or new arguments?
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