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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 103801 to 103850:

  1. It's the sun
    #731: "The glacial cycle would seem to have made a much bigger difference " The 'glacial cycle' is a result, not a cause. Increased atmospheric CO2 is a causative agent (aka 'forcing') of increased warming. See CO2 is not the only driver. Please find the appropriate threads for further comments about whatever you refer to as 'cycles' -- this is 'its the sun'.
  2. The question that skeptics don't want to ask about 'Climategate'
    #99: "Given what has been reported in the press about suppression of articles critical to the AGW premise," If by press, you mean the usual crowd of denial blogs, conservative 'think-tanks' or the claims of the ID crowd that they aren't allowed to 'teach the debate'. But on balance, you've got it backwards: Hansen on censored science Research findings suppressed by government
  3. The question that skeptics don't want to ask about 'Climategate'
    John's Original Post and Marco: "The evidence for human caused global warming is as solid as ever." Why don't we ask Dr Trenberth a lead author and recognized expert on the forcings and energy balances: This excerpt from the NP and Climategate emails: Quote: The 2001 Synthesis Report looked authoritative in its carbon and temperature outlooks. But one of the “lead authors” was Kevin Trenberth, head of the Climate Analysis Section at the National Center for Atmospheric Research in Colorado. Eight years later, Mr. Trenberth shows up in the emails. On Oct. 14, 2009, he wrote to Tom Wigley: “The fact is that we can’t account for the lack of warming at the moment and it is a travesty that we can’t. The CERES data published in the August BAMS 09 supplement on 2008 shows there should be even more warming: but the data are surely wrong. Our observing system is inadequate.” In other words, one of the lead authors of the 100-year climate forecasting exercise says there’s something wrong with the models —or the data. End Quote Ref: http://network.nationalpost.com/np/blogs/fpcomment/archive/2009/12/18/terence-corcoran-a-2-000-page-epic-of-science-and-skepticism-part-1.aspx#ixzz15pLvdnlg Before you all scream 'out of context' - please consider in what context such an opinion of a leading expert in this field and lead IPCC author would support the proposition that "The evidence for human caused global warming is as solid as ever."
  4. Climategate a year later
    KL #44 Why do you waste your time with that comment, when you could try and provide a sensible answer to #37 instead? If you managed that it would greatly strengthen your argument. However the fact that you won't or can't looks to me like a tacit acknowlegement that your argument is on extremely thin ice.
  5. The Fake Scandal of Climategate
    Kudos, Jame. Agree with David Horton.
  6. The human fingerprint in the daily cycle
    #7: "Why should greenhouse gases (GHGs) reduce diurnal temperature range (DTR)?" You've answered your own question: "GHGs reduce that radiation loss both day and night." During the day, there is more incoming solar radiation, so the ground/water heat up or maintain an equilibrium. At night, there is no incoming solar radiation, so the ground gives up heat with little to replace it - except by conduction/convection. Since more GHGs are in the atmosphere, more of that outgoing LWIR is trapped -- and what should be cooler nights turn into warmer nights. Here's a primer: CO2 ... traps radiation or heat given off by the earth. This captured heat warms the lower atmosphere, preventing strong nighttime cooling. Carbon dioxide levels are highest near industrial sections since carbon dioxide is the by-product of combustion, a common manufacturing process. The atmosphere surrounding large cities contains higher concentrations of carbon dioxide, thus nighttime cooling in large cities is less than in surrounding areas.
  7. The Fake Scandal of Climategate
    thank you, James. It is a very transparent paper and I will use it within my paper on the situation - which is similar here in Germany - Contrarians contra Mainstream
  8. Climategate a year later
    Marco #41 Give me your email address and I will snd you my last 14 years of business emails. They will cure your insomnia. I am sure you will agree with my radical personal opinion expressed to my Yankee associates in there somewhere that George W. Bush is vying for the title of worst US President of all time with Rutherford Hayes. I have no reason to not accept the truth of the below excerpt from NP: "Mr. Mann meddled in other ways. In January 2005, he called the editor of Geophysical Research Letters, the official science publication of the American Geophysical Union, to try to head off a paper by Mr. McIntyre. The editor, Steve Mackwell, defends the decision to publish and tells Mr. Mann that the McIntyre paper has been thoroughly peer reviewed by four scientists. “You would not in general be asked to look it over,” Mr. Mackwell told Mr. Mann. Later in 2005, Mr. Mann wrote to Mr. Jones on their troubles with the GRL journal after Mr. Mackwell’s term as editor was up: “The GRL leak may have been plugged up now w/ new editorial leadership.” Reference: http://network.nationalpost.com/np/blogs/fpcomment/archive/2009/12/21/terence-corcoran-a-2-000-page-epic-of-science-and-skepticism-part-2.aspx#ixzz15p66k1Ad Now you have mis-represented your 'rejection' of a paper in a peer review process with what is described in the above excerpt. The two are not the same. The Mann incident is an attempt to interfere with a peer review process at GRL which had already been conducted by 4 scientists by pressuring the Editor. When the Editor's term expired, Mann described it as a "leak which has been plugged"!! A leak in what - a well respected journal of record such as GRL was 'leaking' - leaking what? Clearly anything which Mr Mann and his colleagues did not agree with. And clearly the new Editor of GRL was 'their man (or woman)' because now the leak had been plugged. So now Marco - your honest appraisal and rejection of a paper in your role as peer reviewer you seem to regard as equivalent of 'suppressing other people's work'. Oh dear Ken, thats what we do in science as gatekeepers of the citadel. Amen. Dear Marco, it all depends on your reasons for rejecting other peoples' work, and whether you improperly attempt to compromise the independence of other peer reviewers or pressure Editors to interfere with a properly conducted peer review process. If that cap fits - wear it!
  9. The Fake Scandal of Climategate
    batsvensson it does not make much sense to quibble on the numbers or on who is and who is not. The point James is making should be clear enough to anyone, the double standard.
  10. The Fake Scandal of Climategate
    "Climate scientists have to be right 100% of the time, but contrarians apparently can get away with being wrong nearly 100% of the time." Says who?
  11. The Fake Scandal of Climategate
    Good work James, I disagree with gp. It is past time we all got angry, very angry, at what these people have done and continue to do. Dispassionate science doesn't cut it with the denial industry or with the media (and that "or" really isn't there). It's time to fight back with everything we can throw back at them.
  12. The Fake Scandal of Climategate
    It's not about science, indeed. But I think we should not let politically motivated people intentionally ignore the clearings of the allegations and mislead the public. I hope that we'll not see other agressions to scientist so we, and scientists in first place, can only focus on the science of climate change. But I'm not that optimistic.
  13. Dikran Marsupial at 21:14 PM on 20 November 2010
    The question that skeptics don't want to ask about 'Climategate'
    cjshaker @ 99 Firstly, Nature is pretty much *the* top journal in the natural sciences, publishing there is *extremely* competitive and the paper needs to be excellent and essentially flawless to get published. E&E, on the other hand is pretty much the bottom of the pile - if M&M had wanted the paper published in a peer reviewed journal there are plenty that they could have chosen that lie somewhere in the spectrum between Nature and E&E. Not getting published in Natura is not the same as not being able to get published. What generally happens is that an author will send a paper to the best journal that he/she thinks will accept it. If it gets rejected, it gets submitted to a journal on the next rung down on the ladder (hopefully after having been revised to take into account the reviewers comments). Eventually if the paper has any merit it will get published; generally the stature of the journal where it gets published is an indication of the quality of the publication. As for Shaviv, the authors responses to papers do not routineley get sent to the reviewers is the paper is rejected without the option of resubmitting (which is what happens if the paper has a fundamental flaw). I very much doubt an editor should give a comment like "any paper which doesn’t support the anthropogenic GHG theory is politically motivated, and therefore has to be rejected" in writing - it would be a cereer limiting move - you have to ask yourself why has the rejection letter/email not been published as evidence of editorial bias? As a scientist myself that has published, reviewed and edited journal papers, neither story is very convincing.
  14. The human fingerprint in the daily cycle
    Jeff T @7 - It's not obvious to me that the effect of GHGs should be greater at night. You make a valid point. Further to Ari's suggestion: Effects of Clouds, Soil Moisture, Precipitation, and Water Vapor on Diurnal Temperature Range "The nighttime minimum temperature is largely controlled by the greenhouse effect of lower atmospheric water vapor, while the daytime maximum temperature depends heavily on the surface solar heating, which is strongly affected by cloud cover, and the amount of it that is released into the air by sensible and latent heat, which depends on soil moisture content."
  15. The question that skeptics don't want to ask about 'Climategate'
    cjshaker and others have not raised anything new in respect to this subject. There are two outcomes to all this: 1. The science is correct. 2. The CRU made management mistakes and is correcting them. eg. all outcomes are positive.
  16. 10 Indicators of a Human Fingerprint on Climate Change
    I have just realised that most of the observations in the illustration is strictly not evidence of anthropologically induced global warming, only global warming. Natural warming could induce more water vapour into the atmosphere producing many of these radiative effects. The remaining observations only suggest that we have simply released more carbon into the atmosphere! To show AGW we need to show a) the basic theory of GHG warming in conjunction with evidence that these GHGs are human based (eg. from isotopic analysis), you have done this elsewhere. b) the measured relationships between GHGs and temperature, particularly the sudden rise in global temperatures when large quantities of carbon emissions were first released around 1900. Have any statisticians assessed the probability this rapid change, in conjunction with GHG concentrations might have happened by chance (the null hypothesis). I guess this would be very low. c) the absence of any plausible natural mechanism, once again you have covered this elsewhere.
  17. The question that skeptics don't want to ask about 'Climategate'
    Philippe Chantreau: "The FOI requests thing is so abusive that anyone who really cares about conserving the FOI process should be concerned." Indeed. The CRU was 'spammed' and failed to manage the issue adequately.
  18. The question that skeptics don't want to ask about 'Climategate'
    cjshaker: "If it can't stand up to a hostile researcher, it is not science." Your description of 'hostile research' doesn't sound like science to me, it sounds like business, PR and business competition.
  19. The question that skeptics don't want to ask about 'Climategate'
    cjshaker: "Some of the hacked emails reveal scientists encouraging their colleagues to delete emails, apparently to prevent them from being revealed to people making FOI requests." 1. It didn't happen, as Phil Jones has pointed out in Nature. 2. It wouldn't be illegal in any case, because an FOI request for the emails hadn't been placed before the suggestion to delete emails was made. There isn't a requirement to archive emails!
  20. The question that skeptics don't want to ask about 'Climategate'
    cjshaker: "Regarding the post from whomever 'The Ville' is, I provided the link to an article which talked about the reported failure to follow FOI laws, and the deleting of emails." UK FOI law doesn't require emails to be kept in advance of an FOI request. eg. if the email is deleted and then later a copy is requested at a later date, the law is not broken.
  21. The question that skeptics don't want to ask about 'Climategate'
    cjshaker: "So far, I have not yet found your post where I assume you do the same." My reference is myself, because unlike you, I went to a public meeting of climate scientists including Mike Hulme. eg. first hand direct info, instead of second or third hand info from a news paper.
  22. The question that skeptics don't want to ask about 'Climategate'
    cjshaker: "Clean up my own act? I just posted comments from sources, and included the actual sources. So far, I have not yet found your post where I assume you do the same. Your main intellectual activity seems to be name calling. It is not very flattering." 1. My comment was about you and your comment. 2. My previous comment stands. If you choose outdated media sources as a reference, then you do indeed meed to clean up your act. 3. Suggesting someone cleans up their act isn't name calling.
  23. The question that skeptics don't want to ask about 'Climategate'
    Chris, peer review normally is brutal. M&M's rejection was not the least unusual for any scientific field. See: Stephan Lewandowsky's The Peer Reviewed Literature Has Spoken. Stephan's Peer Review vs Commercials and Spam. My comment #25 here, My comment #33 but with its correction #35, and my comment #34. My comment #40.
  24. The question that skeptics don't want to ask about 'Climategate'
    Tom: Thank you for the pointers to the documents on temperature deltas. Was wondering why that was done. I think that's enough reading for tonight for me. Drinking from the fire hose again. Chris Shaker
  25. Philippe Chantreau at 19:05 PM on 20 November 2010
    The question that skeptics don't want to ask about 'Climategate'
    "I don't have to pretend to be perfect." Yes but you don't have a rabid herd of lunatics to accuse you of fraud when you happen not to be perfect. Wanna try having them watching you 24/7? Wanna try having them call you a fraud every time that you make an honest mistake? Or just when there is something they don't understand? That wouldn't make you a little defensive? M&M failed to convince Science that their paper was important. The same thing happened to probably 10s of thousands of researchers. Do they go on accusing their entire area of exercice to be fraudulent? Please...
  26. The Fake Scandal of Climategate
    As worthy as this defense is, surely this is the kind of political bun-fight SkS has resolutely stayed away from since its inception. The debate can only become a quagmire of competing claims, because this is part of an adversarial process that does not depend on, or even require, scientific evidence. Only by sticking resolutely to the science and the advocacy of the scientific method can SkS continue to avoid being drowned in the kind of mud through which we are obliged to wade elsewhere.
  27. Philippe Chantreau at 18:55 PM on 20 November 2010
    The question that skeptics don't want to ask about 'Climategate'
    Nonsense. A skeptic once posted on this site a compilation of 700 papers that were skeptical of AGW, how do they do it? As I said, McLean et al was published, Lindzen was published, and Spencer etc, etc. It's quite possible Shaviv's paper was bad, it happens. Sometimes a paper is rejected for no good reason (or so it seems to the author), it happens in biology, chemistry, archaeology, any and all area. You try again, or you try another journal or you put it on the shelf until you can make it better and you move on. If you don't move on and just go on belly aching about how it's all unfair you end up never publishing anything. That's life.
  28. The question that skeptics don't want to ask about 'Climategate'
    Adelady: We all make mistakes. In my life, I've been better served by being up front with my numerous mistakes, and letting the chips fall where they may. I don't have to pretend to be perfect. Chris Shaker
  29. The question that skeptics don't want to ask about 'Climategate'
    Chris, temperatures are converted to anomalies to reduce noise. See NCDC (hat tip to the Yooper) and the IPCC Working Group I report from the TAR.
  30. Economic Impacts of Carbon Pricing
    actually thoughtful, $4 per gallon? Yesterday morning, petrol was 1.33 a litre at my nearest servo, which is just over $5 a US gallon. I managed to buy some in the afternoon for the wonderful bargain price of 1.15. $4.35 a gallon. I do not understand why petrol is so cheap in the USA. I do not understand why people think that the USA could not survive if prices were higher.
  31. The question that skeptics don't want to ask about 'Climategate'
    Phillipe: Given what has been reported in the press about suppression of articles critical to the AGW premise, criticizing someone for not having a peer reviewed article may be a circular argument. Given what Dr. Muller says on his website, I'm not surprised that M&M were unable to get a paper published. http://muller.lbl.gov/ "Some people may complain that McIntyre and McKitrick did not publish their results in a refereed journal. That is true--but not for lack of trying. Moreover, the paper was refereed--and even better, the referee reports are there for us to read. McIntyre and McKitrick's only failure was in not convincing Nature that the paper was important enough to publish." Here is one from Israeli Astrophysicist, Nir Shaviv: "I witnessed how an editor rejected a paper I wrote without forwarding the reviewers my detailed response to their comments (he was perhaps afraid that the reviewers would actually be convinced with my detailed response which included detailed referrals to published results proving my points). I saw another rejection (perhaps by the same editor...), this time of a paper written by a colleague that included the punch line: "any paper which doesn’t support the anthropogenic GHG theory is politically motivated, and therefore has to be rejected" I saw how proposal reviewers bluntly reject funding requests, based on similar beliefs in the global warming apocalypse. I even know of someone who didn't get tenure because he advocated non party line ideas. " From http://www.sciencebits.com/node/211 Chris Shaker
  32. The question that skeptics don't want to ask about 'Climategate'
    They address third party data that was not generally accessible, but now is archived: "24. On the allegations in relation to withholding data, in particular concerning the small sample size of the tree ring data from the Yamal peninsula, CRU did not withhold the underlying raw data (having correctly directed the single request to the owners). But it is evidently true that access to the raw data was not simple until it was archived in 2009 and that this delay can rightly be criticized on general principles. In the interests of transparency, we believe that CRU should have ensured that the data they did not own, but on which their publications relied, was archived in a more timely way. " They address the FOI act as well: "27. On the allegation that CRU does not appear to have acted in a way consistent with the spirit and intent of the FoIA or EIR, we find that there was unhelpfulness in responding to requests and evidence that e-mails might have been deleted in order to make them unavailable should a subsequent request be made for them. University senior management should have accepted more responsibility for implementing the required processes for FoIA and EIR compliance. " They criticize University Management for not having proper FOI compliance procedures in place. I'll ask some possibly stupid questions regarding this paragraph: "One of CRU‘s most important contributions to climate science is the production of a land based, gridded temperature data set showing how the temperature has varied year by year since 1850 relative to the 1961 to 1990 average." I noticed that convention, of storing a delta from a temperature average in looking at the temperature proxy data extracted from the ice cores. Why do they store a delta? And what is the 1961 to 1990 average? Is it some kind of global average? Or an average for the reporting station over that time period? Thank you, Chris Shaker
  33. Climategate a year later
    Contact me directly, Daniel (I guess someone from the website can see my e-mail address, I'm not going to publish it here!).
  34. The question that skeptics don't want to ask about 'Climategate'
    What justification would they have had for withholding station identifiers? I assume that is just the ICAO name of the weather reporting facility? http://www.cce-review.org/pdf/FINAL%20REPORT.pdf "18. On the allegation of withholding station identifiers we find that CRU should have made available an unambiguous list of the stations used in each of the versions of the Climatic Research Unit Land Temperature Record (CRUTEM) at the time of publication. We find that CRU‟s responses to reasonable requests for information were unhelpful and defensive." Chris Shaker
  35. The question that skeptics don't want to ask about 'Climategate'
    Philippe: Your post seems to be saying that the FOI laws need to be updated to add a 'rate limiting' feature, and or some way of preventing them from being used for harassment? A friend of mine who is currently working on modeling fire fighting systems told me about how distracting some of the scientists find the FOI requests. I'm currently reading the report that Daniel pointed me at: http://www.cce-review.org/pdf/FINAL%20REPORT.pdf I like the fact that the panel of reviewers were not climate scientists. Seems like a diverse group of well educated people did the review. They also say "15. But we do find that there has been a consistent pattern of failing to display the proper degree of openness, both on the part of the CRU scientists and on the part of the UEA, who failed to recognise not only the significance of statutory CHAPTER 1: EXECUTIVE SUMMARY 12 requirements but also the risk to the reputation of the University and, indeed, to the credibility of UK climate science. ". Continuing to read. Thank you for the pointers, Chris Shaker
  36. The question that skeptics don't want to ask about 'Climategate'
    chris@88 You didn't look very hard. If you go to Mann's CV you'll find a list of publications when you scroll down (a fair way, he's a busy man). You can count for yourself the number of _listed_ publications since the date you seem to be worried about. Many commentators, including your good self, behave like literature critics getting stuck into a writer because characters or plot seem a bit underdeveloped in the first chapter of a book. The fact is that everyone who's read the rest of the book says that none of this matters because the whole book is well written. Dr Mann's done what all scientists do. He's kept on working and produced better and better work. Is the reason that people harp on about this early piece that they've found nothing to criticise in the many, many papers he's since written? So they have to stick with nagging about the one and only thing they have any argument at all with.
  37. Philippe Chantreau at 17:30 PM on 20 November 2010
    The question that skeptics don't want to ask about 'Climategate'
    CJ, Mann et al 2008 has similar findings to the paper you allude to, using different methods and data. The data and code are available. Have McIntyre and McKitrick attempted to publish anything about it? How about the multiple other reconstructions that show similar results? In fact, exactly how many papers have M&M attempted to publish in the many years of casting suspicion and spreading rumors about fraud, conspiracy and what not? How many have they actually published? Do they even bother with trying E&E, where skeptics can have their say to the exclusion of all others? If papers as poor as Soon&Baliunas or McLean et al made it to peer-review, surely the serious work of M&M should pass, shouldn't it? So why is there none to be read?
  38. The question that skeptics don't want to ask about 'Climategate'
    Re: cjshaker (88-90) 1. RealClimate is not Michael Mann's website. Mann's site is here. 2. The McIntyre and McKitrick paper is overblown. They had a minor point, it was adopted, the reconstructions were re-done. The result? Hockey sticks. With or without PCA. With or without tree ring data. Read it for yourself, here. If you have any questions after reading this post, come back here and ask. (slow typist I am, I see Tom Dayton already linked this for you) 3. Read the Muir Russell report for context on the stolen emails. The true hallmark of intellect is to rise above what one is taught, to see the merits and weaknesses of the teachings, and to surpass the teacher. You have the intelligence, Chris. I have pointed the way to you. But it's a looonnngggg road to the truth. And few walk it. And fewer still reach the destination. Will you? The Yooper
  39. The human fingerprint in the daily cycle
    This is just my own thinking here without looking into the scientific literature on the matter: I think the reason for DTR decrease has something to do with the differences in the ratios of the forcings during the day and during the night. During the day the sun contributes to the temperature strongly and GHG forcing is not so large player during the day. During the night the solar forcing gets very small and GHG forcing dominates. If GHG forcing increases, it has larger effect during the night because its fraction of the whole forcing is bigger then.
  40. The question that skeptics don't want to ask about 'Climategate'
    Chris, type "hockey stick" into the Search field at the top left of this page. Do the same in the Search field at the top right of any page on RealClimate. In particular, read the article by the statistician Tamino, titled The Montford Delusion. I have studied statistics, and used it as a scientist, and taught it to PhD students, and peer-reviewed the statistical aspects of submissions to scientific journals. I am not anywhere close to having Tamino's expertise, but I am expert enough to judge his opinion is well grounded.
    Moderator Response: In particular, see "Hockey stick is broken."
  41. Philippe Chantreau at 17:17 PM on 20 November 2010
    The question that skeptics don't want to ask about 'Climategate'
    Cjshaker, you did not fully read. They do things with the data: cherry-picking, misrepresentations, distortions, innuendo, gratuitous attacks on people's integrity, all summed in blog posts with shocking titles. The FOI requests thing is so abusive that anyone who really cares about conserving the FOI process should be concerned. One of McIntyre's blogposts generated 48 FOI requests in a week-end. That qualifies as harassment. Not suprisingly, that's when bloggers have more time on their hands. A disproportionate share of these requests were for private communications instead of material useful for research. As for your confession that you need pointers and clues to look into the reality of this, it unfortunately indicates that your investigation has so far been superficial. Real Climate has a good search engine. However, if you really care, forget about news reports. Look at peer-reviewed litterature. If the research was really flawed, everyone looking to make a name in science (that's a lot of sharp young people) would have latched on, gone over the "bad stuff" and published rebuttals. New findings or comments on existing papers would have flourished. Has that happened? Of course not. Climategate is a mountain out of a molehill, a non-story not worthy of any attention if one cares to actually try to understand the state of scientific knowledge in the field.
  42. The question that skeptics don't want to ask about 'Climategate'
    Daniel: I think the quotes that I've mined from the articles reflect poorly on the scientists involved, and do not make climate science look very credible to the general public. I'm not sure how I'm supposed to ask questions about Climategate, or respond to questions without using sources and quoting from them... Chris Shaker
  43. The question that skeptics don't want to ask about 'Climategate'
    Daniel: I have not seen any claims that these quotes from scientists who appear to be behaving poorly were fabricated. Have I missed such? Thank you, Chris Shaker
  44. The question that skeptics don't want to ask about 'Climategate'
    RealClimate seems to be Dr. Mann's webpage. I have looked at it before, attempting to see any acknowledgement of the problems with statistics supposedly identified in his work. Professor Muller at Berkeley claims to have also verified problems with his statistics work. Search for 'Global Warming Bombshell' at http://muller.lbl.gov/ "But now a shock: Canadian scientists Stephen McIntyre and Ross McKitrick have uncovered a fundamental mathematical flaw in the computer program that was used to produce the hockey stick. In his original publications of the stick, Mann purported to use a standard method known as principal component analysis, or PCA, to find the dominant features in a set of more than 70 different climate records. But it wasn't so. McIntyre and McKitrick obtained part of the program that Mann used, and they found serious problems. Not only does the program not do conventional PCA, but it handles data normalization in a way that can only be described as mistaken. Now comes the real shocker. This improper normalization procedure tends to emphasize any data that do have the hockey stick shape, and to suppress all data that do not. To demonstrate this effect, McIntyre and McKitrick created some meaningless test data that had, on average, no trends. This method of generating random data is called "Monte Carlo" analysis, after the famous casino, and it is widely used in statistical analysis to test procedures. When McIntyre and McKitrick fed these random data into the Mann procedure, out popped a hockey stick shape! That discovery hit me like a bombshell, and I suspect it is having the same effect on many others. Suddenly the hockey stick, the poster-child of the global warming community, turns out to be an artifact of poor mathematics. How could it happen? What is going on? Let me digress into a short technical discussion of how this incredible error took place. In PCA and similar techniques, each of the (in this case, typically 70) different data sets have their averages subtracted (so they have a mean of zero), and then are multiplied by a number to make their average variation around that mean to be equal to one; in technical jargon, we say that each data set is normalized to zero mean and unit variance. In standard PCA, each data set is normalized over its complete data period; for key climate data sets that Mann used to create his hockey stick graph, this was the interval 1400-1980. But the computer program Mann used did not do that. Instead, it forced each data set to have zero mean for the time period 1902-1980, and to match the historical records for this interval. This is the time when the historical temperature is well known, so this procedure does guarantee the most accurate temperature scale. But it completely screws up PCA. PCA is mostly concerned with the data sets that have high variance, and the Mann normalization procedure tends to give very high variance to any data set with a hockey stick shape. (Such data sets have zero mean only over the 1902-1980 period, not over the longer 1400-1980 period.) The net result: the "principal component" will have a hockey stick shape even if most of the data do not. McIntyre and McKitrick sent their detailed analysis to Nature magazine for publication, and it was extensively refereed. But their paper was finally rejected. In frustration, McIntyre and McKitrick put the entire record of their submission and the referee reports on a Web page for all to see. If you look, you'll see that McIntyre and McKitrick have found numerous other problems with the Mann analysis. I emphasize the bug in their PCA program simply because it is so blatant and so easy to understand. Apparently, Mann and his colleagues never tested their program with the standard Monte Carlo approach, or they would have discovered the error themselves. Other and different criticisms of the hockey stick are emerging (see, for example, the paper by Hans von Storch and colleagues in the September 30 issue of Science). Some people may complain that McIntyre and McKitrick did not publish their results in a refereed journal. That is true--but not for lack of trying. Moreover, the paper was refereed--and even better, the referee reports are there for us to read. McIntyre and McKitrick's only failure was in not convincing Nature that the paper was important enough to publish. " I looked for this to be addressed at RealClimate.org, and found this condescendingly named article, which should be addressing the claims: http://www.realclimate.org/index.php/archives/2005/02/dummies-guide-to-the-latest-hockey-stick-controversy/ I don't actually see Professor Muller's claims about the supposedly easy to understand mistake being addressed. I have NOT studied statistics. It appears that Professor Muller is well respected in the scientific community, as far as I can tell. Did Dr. Mann screw up? If so, did he ever admit his mistake? Thank you, Chris Shaker
    Moderator Response: Please do not post such long quotes. Instead link to the source, and direct readers to the most relevant portions, and perhaps provide a few highlights.
  45. The question that skeptics don't want to ask about 'Climategate'
    Re: cjshaker (81) Here's a link to the Muir Russell report. The relevant section is Pp 45-48. Links to the openly available datasets are therein, as well as the methodology used by the investigative team. In light of the multiple investigations (and exonerations in every instance) into this matter, your quote-mining of the WSJ piece you link (and others) reflects poorly on you. Here's the latest Skeptical Science post on this matter. Consider it a must-read for anyone maintaining to have an open mind. (-edit: fixed, thanks! -end edit-) The Yooper
    Moderator Response: The second link is broken.
  46. The question that skeptics don't want to ask about 'Climategate'
    As a member of the public, Climategate is what got me interested in reading about the whole issue of AGW, and the controversies surrounding it. I was reading articles like this one, which talks about suppression of opposing views from scientific journals, and subverting the peer review process: http://www.guardian.co.uk/environment/2010/feb/02/hacked-climate-emails-flaws-peer-review ---------------------------------------------------------------------------- "In another email exchange CRU scientist Dr Keith Briffa initiates what looks like an attempt to have a paper rejected. In June 2003, as an editor of an unnamed journal, Briffa emailed fellow tree-ring researcher Edward Cook, a researcher at Lamont-Doherty Earth Observatory in New York, saying: "Confidentially I now need a hard and if required extensive case for rejecting [an unnamed paper] – to ­support Dave Stahle's and really as soon as you can. Please." Stahle is a tree-ring professor from the University of Arkansas. This request appears to subvert the convention that reviewers should be both independent and anonymous. Cook replied later that day: "OK, today. Promise. Now, something to ask from you." The favour was to provide some data to help Cook review a paper that attacked his own tree-ring work. "If published as is, this paper could really do some damage," he said. "It won't be easy to dismiss out of hand as the math appears to be correct theoretically, but it suffers from the classic problem of pointing out theoretical deficiencies, without showing that their improved [inverse regression] method is actually better in a practical sense."" Chris Shaker
  47. The question that skeptics don't want to ask about 'Climategate'
    Better than that, Chris, is RealClimate's page of links to data and code.
  48. The question that skeptics don't want to ask about 'Climategate'
    Tom, DeVille, etc: I'm happy to read news reports that should have told me that the data they were seeking was actually available, if you'd like to point me at them. Or, give me a clue about what to search for with Google, and I'll take a crack at it. Chris Shaker
  49. The human fingerprint in the daily cycle
    Jeff T, I don't know why DTR should decrease due to GHG increase. But I do know that increased radiance from the Sun should increase DTR by increasing day temperatures more than night temperatures. DTR's failure to increase is yet more evidence that the Sun is not to blame for overall warming.
  50. The question that skeptics don't want to ask about 'Climategate'
    cjshaker, the few agencies that withhold some of their data from free distribution do so in order to charge for the data, to fund the data's collection and archiving. Many of the agencies that distribute their data for free insist that the distribution come from them alone rather than second hand, to help ensure that anyone thinking they have the data really do have the real data rather than a version that might be incomplete or erroneous.

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