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Comments 45501 to 45550:

45501. CBDunkerson at 00:27 AM on 18 May 2013
       A 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.

45502. Tom Curtis at 00:21 AM on 18 May 2013
       It 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".

45503. Warren Hindmarsh at 00:18 AM on 18 May 2013
       It 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). 

45504. Tom Curtis at 00:18 AM on 18 May 2013
       It 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?

45505. Tom Curtis at 00:15 AM on 18 May 2013
       Measure 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.

45506. Alexandre at 00:13 AM on 18 May 2013
       Measure 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

45507. Warren Hindmarsh at 00:12 AM on 18 May 2013
       It hasn't warmed since 1998
       

       what is wrong with this graph

45508. adelady at 00:09 AM on 18 May 2013
       Measure 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.)  

45509. Warren Hindmarsh at 00:06 AM on 18 May 2013
       It hasn't warmed since 1998
       

       Hi dikran

       where is  the global warming :)

45510. Tom Curtis at 00:05 AM on 18 May 2013
       A 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.

        

45511. K.a.r.S.t.e.N at 00:04 AM on 18 May 2013
       The 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.

45512. Warren Hindmarsh at 00:03 AM on 18 May 2013
       Skeptical 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  

45513. Dikran Marsupial at 23:49 PM on 17 May 2013
       Skeptical 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.

45514. Tom Curtis at 23:49 PM on 17 May 2013
       Skeptical 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? 

45515. JvD at 23:30 PM on 17 May 2013
       A Detailed Look at Renewable Baseload Energy
       

       I'd like to have a show of hands at this point of people who - having followed this discussion - agree with me that SkS is creating a false impression that 100% renewables scenario's are realistic. I call this creating a false impression, because in reality, achieving 100% renewables (global average!) has been stated by numerous credible sources to be extremely difficult which is another way of saying extremely costly.

       My proposal here is that SkS overhaul its various articles that conclude that 100% renewables scenario are credible.

       For example, the final sentence of this particular article is:

       "Numerous regional and global case studies – some incorporating modeling to demonstrate their feasibility – have provided plausible plans to meet 100% of energy demand with renewable sources."

       Should be updated to read:

       "Numerous regional and global case studies – some incorporating modeling to demonstrate their feasibility – have provided plans to meet 100% of energy demand with renewable sources, although achieving such plans globally is thought to be extremely difficult and costly, according to authoritative expert bodies"

       I have re-read most of this entire discussion (which took almost an hour) and I think that we could all agree that SkS should now move to create the above example amendment to this article. It would be sensible to update the other articles on renewables providing 100% power or baseload power to reflect this conclusion. It is necessary that SkS does this, because the current purport of all these articles is that renewable can 'plausibly' provide 100% of energy without any nuclear.

       SkS needs to update the articles to make sure that people realise that achieving 100% renewables can only be done with extreme difficulty. It is right and just that readers of Sks should realise this fully, and not be moved to complacency on this issue, which is what the current version of the articles are apparently seeking to do!

       Thank you,

       Joris

45516. DSL at 23:16 PM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       Warren, I'm sure you'll agree that only those who offer an opinion can be applied to the concept of "consensus."  Climate in particular is an interdisciplinary area of study, and not all biologists and oceanographers should be expected to be included in the category of "contributing to the consensus."  If we use that definition, then only those who offer a point of view on the "A" in AGW can be counted, even if their opinion is "I'm not sure" (which is different than not offering an opinion at all).  It is implicit, then, in the use of the concept of consensus that it refer only to those who offer an opinion.
       
       

       To say something like "of 12,000 papers, 30% endorse" is much more misleading, unless the full range of responses is given at that point.  In such a case, the scientific reader will immediately discard the "no opinion offered" and do the math to arrive at 97%.  The mainstream reader will be confused and either take 30% in the wrong way (only 30% believe in AGW!) or figure things out and get the 97%.  If the most useful and precise result is 97%, why obscure it?

45517. Dikran Marsupial at 22:59 PM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       Warren, the large eye-catching diagram at the top of the page makes it abundently clear that it is 97% of the papers that state a position on the matter, so it is only potentially misleading to those who can only be bothered to read the title and read no further.  Has the climate debate really reached the point where statements need to be worded that defensively?

45518. Kevin C at 22:44 PM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       Warren: Let me try and explain this one more way.

       In 2004 GW Bush won the presidential election with 62m votes, or 50.7% of the votes cast. 62m is also 21% of the US population (not all of whom were eligable to vote), and <1% of the global population. Was the popular support for GW Bush 50.7%, or 21%, or <1%?

       I submit to you that any answer other than 50.7% would be misleading.

       You are suggesting that papers which do not address the question of the human contribution to global warming in the same category as papers which do address the question but are undecided on the answer. That's the sort of meaningless abuse of statistics which, while common in public discourse, has no place in science.

45519. Warren Hindmarsh at 22:40 PM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       Sphaerica,

        it is misleading because 97% of the survey did not find "that humans are causing global warming"

       by the reports own results around 4,000 of 12-14,000 reports found so ie around 30%

       It doesn't matter what is written in the rest of the report. that sentence is misleading.

       "in 1969 man walked on the moon" is completely different. there you are considering the definition of "man"  

        

45520. CBDunkerson at 22:35 PM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       yphilj - When Arrhenius first suggested AGW in 1896 it was almost universally rejected based on bad data and methodology regarding the infrared absorption capability of increased CO2 levels. The idea was essentially resurrected by Callendar in the late 1930s and grew slowly more accepted from there as the evidence began piling up.

       I suspect the turning point was the 'Keeling curve' starting in 1958. By then the radiative absorption errors had been corrected, but there was still a prevailing belief that ocean uptake of carbon would prevent atmospheric CO2 levels from increasing for centuries... until Keeling's data definitively proved that they were already rising.

       As Kevin C indicated, AGW was clearly the majority opinion by the 1970s, but did not reach the current near universal acceptance until the early 1990s... just under a hundred years after Arrhenius. Really, at this point the only ways to reject AGW are to not understand the science or believe in a massive unknown and undetected negative feedback effect.

45521. Bob Lacatena at 22:24 PM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       Warren,

       There's nothing remotely misleading about the statement.  Every element of it is true.  To call it misleading is like saying that "In 1969 man walked on the moon" is misleading, because the effort took a decade, and only one man actually walked on the moon, and his feet never touched the moon itself becase he had to wear a spacesuit, and they were only there for a few days.

       In this case, the paper is open access and anyone can read it.  There's also an entire blog post above that explains it more clearly, as well as press releases, press articles, and more.

45522. Alexandre at 22:21 PM on 17 May 2013
       Measure the climate consensus yourself with our Interactive Rating System
       

       Very good. If someone thinks the ratings were not adequate, they can see for themselves.

45523. Warren Hindmarsh at 22:09 PM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       In today's world of "climate science" it is very important to only publish clear and incisive reports, the opening sentences to this report are anything but that by any reading.  

       A more accurate opening could be something like:

       A survey by a team from a global warming blog site of 12,000-14,000 papers on global warming or climate change found that around 4,000 expressed a direct opinion on the causes, of these around 97% endorsed AGW around 30% of the total papers.  Coincidentally of 8,500 authors asked to rate their own papers of these 4,000 responded, of the 1,400 respondents expressing an opinion on global warming or climate change 97% endorsed AGW, around 30% of the self rated respondents.

       I agree quite convoluted:

       Or you could write something like:

       Of 14,000 papers on global warming or climate change surveyed by a team from a global warming blog site, around 30%  endorsed the opinion that the causes were Human induced.  

       But definately not this:

       "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"

       It is misleading

        

        

45524. Glenn Tamblyn at 17:37 PM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       bill

       Yep, a tweet from POTUS is Twitter GOLD. Also a tweet from Rep Waxman (of Waxman-Markey) as well

       This is now generating a second round of media attention, particularly from the US. John Cook has already done one interview on CNN.

45525. scaddenp at 13:58 PM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       Bob, Ray only talked about plate tectonics. Plate tectonics did arise in the 1960s, and it did gain very quick acceptance. The old theory of continental drift lent it a lot of observational support while the new mechanism dealt to the ridiculous idea of contenents moving across oceanic crust. The Wegener theory was wrong and rightly rejected. The key papers appeared in very short interval between 1962 and 1965 and I would say the observations from the  WWSSN and ocean-floor striping discovery were the fundimental keys. It was the standard paradigm by the time I got to uni in 1976.

45526. climateadj at 13:24 PM on 17 May 2013
       Another Piece of the Global Warming Puzzle - More Efficient Ocean Heat Uptake
       

       "So why has ocean heat uptake become more efficient over the past decade instead?"

       My pet theory is that there is the oceanic equivalent of the Hadley Cell at work.  This upwells cold water in the tropics and downwells warm water from the tropical surface out to the mid-latitude depths.  A couple of years ago I produced a plot from the ARGO data showing this:

       

       If the ocean is becoming more energetic, then it's not unreasonable to expect this overturning to increase with the warm water forced deeper.

       Here's a couple of temperature and salinity trend plots that I produced at the same time that might be relevant:

       https://sites.google.com/site/climateadj/argo-analysis

       Only six years of data (2005-2010), but it seemed consistent with the "Hadley" circulation becoming more vigorous with the "warm front" moving more poleward and deep.

       Then again, this is only the pet theory of an amateur.

45527. Bob Loblaw at 12:55 PM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       Ray @56 "Plate techtonics was first elaborated in the 1960s and rapidly gained acceptance."

       Continental drift was promulgated in the early 1900s, by Alfred Wegener, and had origins as far back as the 1500s. It met great resistance amongst many geologists, and some resisted until they died. Plate tectonics finally gave it a mechanism. You give your credibiliity no help by trying to pass it off as a 1960s idea that was quickly accepted.

       There is an interesting distinction between global warming (human-caused by burning fossil fuels) and continental drift, though:

       - continental drift was an observation that languished for years in search of a mechanism, before it became accepted

       - the effect of greenhouse gases and CO2-induced climate change through burning of fossil fuels had a well-accepted mechanism long before observations appeared showing it happening...

45528. bill4344 at 10:57 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       Whoopes, forgot it's not HTML anymore! Should have previewed; Sorry. Tweeted by the POTUS.

45529. Old Mole at 10:27 AM on 17 May 2013
       Who is Paying for Global Warming?
       

       Gentlemen:

       Sorry to have been so late to the discussion, but hasn't it occurred to anyone that the figures in the "% of Total Production Exported" start to get completely cockeyed around Russia? Call me math challenged, but it seems to me that if say, Venezuela exports more than twice as much as it uses domestically, it would amount to more than 1.5%, and that the 20 Mtonnes that China exports out of over 3000 wouldn't amount to nearly 5%.

        

       Could this be corrected?

        

       Best wishes,

       Mole

45530. dhogaza at 10:11 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       Ray:

        

       "However there have been several who have disagreed with all the proposals of plate tectonics leading to comments such as this "Criticism of plate tectonics has increased in line with the growing number of observational anomalies.""

       Google search on that phrase returned four hits, all related to one person, who has published in one place, the "Journal of Scientific Exploration", which specializes in crank science articles that can't get published in the scientific literature.

       " Is this a forerunner of what might happen with the "settled science" of anthropogenic climate change?"

       Crank science rejection of climate science is already with us, of course.  Our cranks will continue to be with us forever, I'm sure.

        

45531. scaddenp at 08:54 AM on 17 May 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
       

       MS1 "I think their paper failed " really? The paper investigated how much of the variability of the temperature record could be accounted from assuming simple relationship with 3 known causes of internal variability.  Rypdal 2012 showed it could be improved but F&R is remarkable successful. Tests with only using part of the data for training show it also a robust predictor of future variability.

       If the ENSO index was substantially flawed or there was significant non-linearity, this isnt born out by the success of their prediction. If you believe that the prediction can be improved significantly by other indexes or method, then show us.

45532. Matt Fitzpatrick at 08:34 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       Re: mattn

       "Why did you use global climate change as a search term rather than anthropogenic...?"

       Probably a precautionary measure. Since survey responders were looking for endorsement of anthropogenicity, using that as a search term could have biased the result. It probably would have reduced the proportion of "neutrals", and may have affected the "endorses" versus "rejects" as well.

       Not to change the subject, but I find the ad hominem and conspiracy ideation I'm seeing in responses elsewhere on the Internet rather depressing. True, that kind of response is nothing new, but since I participated in this (albeit minimally), it's personal now.

45533. dana1981 at 08:31 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       mattn @53 - had we searched for 'anthropogenic', we might have missed some of the 'rejection' studies attributing global warming to other factors.

       It's also possible that a group might investigate certain impacts from 2°C warming (for example) without necessarily accepting that 2°C warming will happen, or if it does, that it would necessarily be human-caused.

45534. Ray at 08:19 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       Composer99 @26.  Not sure that using platre techtonics as an example of settled science in this context is a good idea especially when you couple it with "Third, that humans are causing global warming is not an opinion. Based on the available evidence it is a settled fact".  Plate techtonics was first elaborated in the 1960s and rapidly gained acceptance.  However this was said about this acceptance   "A hypothesis that is appealing for its unity or simplicity acts as a filter, accepting reinforcement with ease but tending to reject evidence that does not seem to fit"   Othersd agreed stating "this is admirable description of what has happened in the field of earth dynamics, where one hypothesis -- the new global tectonics -- has been permitted to override and overrule all other hypotheses."

       You'd have to agree there are some similarities between the current situation on global warming.  But I can hear you say, "plate tectonics is now agreed to by every one and anthropogenic climate change will be also"  However there have been several who have disagreed with all the proposals of plate tectonics leading to comments such as this "Criticism of plate tectonics has increased in line with the growing number of observational anomalies."  Is this a forerunner of what might happen with the "settled science" of anthropogenic climate change?

        

45535. Utahn at 08:16 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       One interesting approach to addressing that concern about adjutication (apologies if in the article), would be to take all the disagreements and judge them in one direction or the other.  This would give you a range of possible outcomes if one person (or one way of leaning) was right or the other.  I bet it woudln't change the final answer much at all, but woudl be kind of interesting.  I suspect most of the shifts woudl be from no opinion to endorsement or vice versa, i.e. changing the proportion with an endorsement or not, but not much the percentages...

45536. Tom Curtis at 08:16 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       yphilj @49, looking at the scientitsts self assessments, in 1991 endorsements constituted approximately 80% of papers that took a position on AGW.  Although a strong majority, that does does not constitute a consensus IMO.  It is, however, based on a small number of repsonses and may not be representative.  Against that, the small number of self assessements still represents about 20-25% of papers assessed in the abstracts, and the IPCC 1990 report certainly did not endorse a consensus that AGW was occurring and significant.  So while Kevin C is correct that a consensus was forming in the 1970s, it did not solidify until the early 1990s.  Certainly it has existed since 2001.

45537. mattn at 08:13 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       Couple questions:

       1) Why did you use global climate change as a search term rather than anthropogenic, which is often used in the literature? I looked at a paper of mine, out of curiousity, and I never used climate change as a phrase even though the paper was on tropical trends in an A1B scenario.

       2) Why are so many of the papers "impacts papers"? These aren't papers about climate science per se, they usually are more along the lines of: given a 2C global increase increase what happens at location x? Also, is there anyone who would write an impacts paper about the impact of no global warming?

45538. Tom Curtis at 07:47 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       Barry @38, the blog by Brandon Shollenberger at Lucia's essentially points out that:

       1) "While criteria for determining ratings were defined prior to the rating period, some clarifications and amendments were required as specific situations presented themselves."

       and that

       2)  "Initially, 27% of category ratings and 33% of endorsement ratings disagreed. Raters were then allowed to compare and justify or update their rating through the web system, while maintaining anonymity. Following this, 11% of category ratings and 16% of endorsement ratings disagreed; these were then resolved by a third party."

       Instead of merely quoting to the paper to that effect (as I have done), however, he has taken some examples out of context from the hacked forum contents and deliberately not quoted the discussion of these points in the paper even though he knew that they existed so as to create the impression that SKS had acted in an underhanded way.

       Victor Venema makes a fair comment on Shollenberger's approach:

       "From Anthony Watts I expect any kind of deception. If something is written on WUWT, by now I initially assume that the opposite is true. From The Blackboard I had a better impression. Had there not been a discussion about the broken link to the article, I might not become suspicious and have checked the article. From now on I will put you in the Watts category until you have shown you deserve better."

45539. Bob7905 at 07:32 AM on 17 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       Kevin C @20

       Thanks for the clarification. I was being dense and had misread what you had suggested @15 for the modified date range.

45540. scaddenp at 06:28 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       Michel, while concensus doesnt mean the science is correct, the scientific consensus is the best basis for policy decisions on just about anything. This paper shows that while there might be debate at politcal level, there isnt at the science level.

45541. Kevin C at 05:36 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       yphilj: That's a very good question. The current paper shows a robust consensus back to 1991. The only similar earlier work I'm aware of is this paper covering the period 1965-1979 (including the 70's of the mythical 'global cooling' predictions). They found 7 papers predicting cooling, 19 neutral and 42 warming.

       Of the cooling papers, one was Rasool and Schneider 1991. By the end of the 70's Schneider had changed his mind. Three more of the cooling papers were equivocal on the question - see Ari's page here.

       On this basis you could probably argue that the consensus was emerging during the 70's.

45542. citizenschallenge at 04:25 AM on 17 May 2013
       Schmitt and Happer manufacture doubt
       

       Scott, I hear you when it comes to the early space program.  Man those astronauts were the coolest, heck they were demi-gods to us kids.  In fact, it took a while for me to accept that Schmitt's fallen off his rocker... but accept it I have.

       But, the main reason I've dropped in - is to say thanks to Dumb Scientist for writing this article and to SkepticalScience for their sharing/reposting policy - which I have again taken advantage of: http://whatsupwiththatwatts.blogspot.com/2013/05/dr-harrison-schmitt-and-dr-william.html

       As for the Wall Street Journal, might I offer some further reading:

       FRIDAY, SEPTEMBER 17, 2010  |  citizenschallenge.blogspot
       {#11a} SPPI, Monckton, Seitz, WSJ - anatomy of a character assassination
       Containing:
       Seitz’s Wall Street Journal, June 12, 1996, Op-Ed

       Ben Santer’s censored reply ~ Wall Street Journal letter to Ed, June 25, 1996

       IPCC’s censored reply ~ Wall Street Journal letter to Ed, June 25, 1996

       ~ ~ ~ ~ ~ ~ ~ 

       Saturday, January 28, 2012

       WSJ claims there’s “No Need to Panic About Global Warming” (part two)

45543. Dumb Scientist at 04:07 AM on 17 May 2013
       Schmitt and Happer manufacture doubt
       

       Dikran's response to jdixon1980 is correct. High CO2 levels hundreds of millions of years ago partially compensate for the fainter young Sun, but that's slow enough to ignore over "only" millions of years.

       Sadly, I didn't notice your other question until just now. I completely agree with KR's comments on that thread, and amusingly also just linked the same page showing that CO2 is rising faster than exponentially.

45544. yphilj at 03:45 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       When did the scientific consensus on climate change decisively emerge?  Early '90s, '80s, earlier?  Is this too subjective a question?  I suppose another way of asking this is when was the last time anthropogentic climate change was seriously argued about in a scientific journal?

45545. Dikran Marsupial at 03:24 AM on 17 May 2013
       Schmitt and Happer manufacture doubt
       

       Assuming that 3,000,000,000 years ago TSI was 20% lower than today and that the Sun had been brightening linearly: 3.2 million years is approximately 1/1000th of that time period so one would expect the drop in lumionosity to be 1/1000th of that 20%, which is essentially negligible (vastly less than the difference in the 11 year solar cycle, which IIRC is about 0.1%).

45546. jdixon1980 at 03:16 AM on 17 May 2013
       Schmitt and Happer manufacture doubt
       

       DS, re: solar activity, your response to Schmitt and Happer points to the obviously directly relevant fact that solar activity hasn't increased significantly since 1950, while global temperature has.  

       I have also read that the sun has an extremely slow trend of increasing intensity, e.g., from the Wikipedia entry on the geologic temperature record:

       "Some evidence does exist however that the period of 2,000 to 3,000 million years ago was very generally colder and more glaciated than the last 500 million years. This is thought to be the result of solar radiation approximately 20% lower than today.[citation needed]"

       and 

       "According to standard solar theories, the sun will gradually have increased in brightness as a natural part of its evolution after having started with an intensity approximately 70% of its modern value."  

       My question is this - what do we know about the solar irradiance at the last time the atmosphere was at 400 ppm, which a brief web search tells me was during the Pliocene epoch, about 3.2-5 million years ago?  If TSI was significantly lower then, wouldn't that tend to suggest that the climate forcing from 400 ppm now will be even stronger than it was the last time, also tending to undermine the denier argument that we shouldn't worry about 400 ppm (and counting) because it has happened before?  

       I must admit that when I started to type this comment, I was confident that the answer to this question was that TSI was much lower a few million years ago, and I was going to suggest that you add that point as another argument against Schmitt and Happer.  But after searching for a bit, it might be that I was just misremembering having read that there is a clear long-term solar warming trend on the time scale of millions of years, when it is actually billions.  Can you or someone here clear me up on this point?    

45547. dana1981 at 03:05 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       bert @25 - our full ratings database should be available in the supplementary material (though I don't have time to look at the moment).

45548. dana1981 at 03:04 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       barry @37 - define what you (or Lucia) mean by "independent".

45549. miffedmax at 02:52 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       This is a great study.

       One thing it shows (and that was really driven home to me when I participated in John's follow-up survey) is how conservative most scientists are with their projections and statements. Where most of us in other fields would be screaming "is" and "will" climatalogists whisper "might be" and "could."

       I  contrast that with the tone of the so-called skeptics who usually speak in sweeping absolutes.

       Anyway, just a few thoughts from a member of the generally unwashed public who has found this site invaluable in getting off the fence when it comes to climate change.

45550. CBDunkerson at 02:48 AM on 17 May 2013
       Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
       

       Wow. I saw a short article on this study earlier today, but somehow didn't make the connection to the SkS project. Now that I search Google News it seems like there is a lot of great press around this. Congrats all!

       Amazing that so many people in this thread apparently would, "...expect every geological paper to note in its abstract that the Earth is a spherical body that orbits the sun?" Just when you think the 'skeptics' cannot get any more ridiculous...

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