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Comments 114651 to 114700:

114651. Peter Hogarth at 01:30 AM on 25 July 2010
        Assessing global surface temperature reconstructions
        Thanks Ned, I wasn't aware of these other individual reconstructions, but it is encouraging to see they are in agreement with the official versions.
114652. RickG at 01:28 AM on 25 July 2010
        Assessing global surface temperature reconstructions
        @ 21. That's one of the reasons anomalies are used rather than absolute temperatures. Think about it.
114653. Doug Bostrom at 01:18 AM on 25 July 2010
        The nature of authority
        Ken, I believe your post here illustrates a fundamental problem with the utility of the "climategate" data, leaving aside entirely questions of the legality or ethics of its provenance. You remark, "The best article on Climategate I have read is by Terrence Corcoran, who analysed the first 5 years of the 13 year record and gives a detailed chronology." Terrence Corcoran cannot render a "detailed chronology" of the thoughts and communications touched upon in the emails in question; the record is acknowledged as incomplete and thus a complete, detailed and fully precise chronology is impossible to produce from what was published. The people who obtained the emails did not provide the rest of us with the complete dataset, they chose to pass along certain portions of the record while redacting other parts. Worse, we cannot know the editorial intentions of those choosing whether we'd be enlightened or remain in ignorance. An example from the National Post article you cited: What really rocked the paleoclimate work at CRU, and ultimately shook the IPCC, was a seemingly out-of-the-blue email on June 17, 1998, from Michael Mann to Phil Jones, then head of East Anglia’s CRU centre. Before then, no mention had been made in the email cache of Michael Mann... "Seemingly out-of-the-blue." Was it? How do we know? Corcoran seems to understand at some level that the detail necessary to draw broad conclusions cannot be derived from what we're allowed to see by the people who obtained the email. Here's how he expresses the problem: The emails are not a random grab of email records from one scientist’s computer or extracted in a coarse raid on the central computer facilities of one climate institute. Only by reading the emails in chronological order, from the first email sent March 7, 1996, by Russian scientist Stephan Shiyatov, from the Laboratory of Dendrochronology, Institute of Plant and Animal Ecology, in Ekaterinburg, Russia — complaining to British scientist Keith Briffa about funding problems for his tree-ring research — does it become clear that the emails are part of a conscious and systematic assemblage of 13 years worth of vital communications among some of the world’s leading climate scientists. Emphasis mine. Corcoran acknowledges an agenda on the part of the people who obtained and disseminated the email as well as their selectivity in deciding what we may or may not know about its content. We can't do science with this sort of data, we're left with intuitions and thus are fully at the mercy of our prejudices. My prejudice leads me to wonder why the folks who obtained and published the emails in question chose to preserve ambiguity over certainty by not providing us with the complete dataset. Is that ambiguity necessary for making the strongest impression, and what would happen to our conclusions if we were able to see the entire record?
114654. muoncounter at 01:09 AM on 25 July 2010
        Assessing global surface temperature reconstructions
        #21: "urban heat island effect" Where have we heard this before? UAH and RSS are satellite temperature measurements. For the global columns in Ned's Fig 8, they average a trend of 0.14ish. All others average 0.16ish; if there is such an effect, then its magnitude is limited by the difference, 0.02 or so. And how does UHI impact the ocean temperatures, which are equally self-consistent? (or is that a part of the conspiracy?)
114655. chris1204 at 01:07 AM on 25 July 2010
        Assessing global surface temperature reconstructions
        David @ 18: Thanks for your kind comments. You're probably right when you say that advances in my field would eventually have come for the right reasons. Still, I do do think the contrarians may have helped stimulate research by highlighting the flaws in the prevailing paradigm. In medicine, many advances occur with serendipity. Often, there's folks out there in underfunded labs beavering away at something highly specialised and obscure in the basic sciences. The relevance to clinical medicine may not be immediately apparent - however, more clinically oriented folk looking for answers stumble across the work and suddenly something very obscure becomes very interesting and hot stuff. Work on the retroviruses focused inter alia on transcription of DNA to RNA (an important topic to be sure) is an excellent example - without that foundation, we would have been very much slower in identifying the HIV virus. We see similar processes in climate sciences - think of the extraordinary interdisciplinary collaboration underpinning GRACE. Phillipe @ 20: I'm conscious of the limitations of WUWT. I did say the readership is far less sophisticated than the bloggers - that's not a glowing endorsement of the bloggers. Some of the posts have a very puerile quality. Still, one does come across enough pieces which are food for thought - hence I visit but almost never post (in marked contrast to this site). In fairness to them, they have put up corrections and counterarguments and more recently they seem to have been trying to align more closely with consensus science. I find it much easier to cope with ideologies I disagree with than with bad faith. While ideology may be impervious to evidence, it has its own internal logic. All of us partake of some ideology (even if we would be loath to call it that). BTW, I have to confess my ignorance: who are G&T?
114656. robert way at 00:54 AM on 25 July 2010
        Assessing global surface temperature reconstructions
        The issue of urban heat island effect is still extremely important to consider in all this though lets remember... I have not seen many reconstructions at all that can effectively keep this effect at a minimum.
114657. Sean A at 00:48 AM on 25 July 2010
        The nature of authority
        Thingadonta, on the definition of theory: "This word is employed by English writers in a very loose and improper sense. It is with them usually convertible into hypothesis, and hypothesis is commonly used as another term for conjecture." In the correct sense, a scientific theory is not a hypothesis. Theory: "a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena; theories can incorporate facts and laws and tested hypotheses."
114658. tobyjoyce at 00:45 AM on 25 July 2010
        The nature of authority
        chriscanaris, @85, I have no problem with a civilzed conversation with the Hulmes and Currys, or with anyone else for that matter. However, when they tell me that there is a point to prolonged exchanges (or "debates") with people who have adopted the tactics of the tobacco industry in relation to science, there I part company with you and them, unless you can convince me otherwise. Gould gave up debating with creationists because (1) it lent the oppsition an intellectual credibility they did not deserve, and (2) the debates were reported by creationists invariably as "Evolutionist gets his ass kicked". You could see the same thing happening in this case.
114659. Philippe Chantreau at 23:50 PM on 24 July 2010
        Assessing global surface temperature reconstructions
        Chris, no work that is rigorous, well thought out and scientifically carried out receives contempt. The likes of Carter et al, Soon-Baliunas or G&T should reeive contempt. The bloggers at WUWT are not that sophisticated. See the Western snow pack thread, CO2 snow, etc... The bad faith mentioned by David above is also patent, I have seen it on a number of occurences, in which Watts trumpeted papers that did not support a "skeptic" position at all as if they actually did. WUWT is not a credible source of information.
114660. Ken Lambert at 23:38 PM on 24 July 2010
        The nature of authority
        DougB #44, JMurphy #49 The best article on Climategate I have read is by Terrence Corcoran, who analysed the first 5 years of the 13 year record and gives a detailed chronology. Links here: http://network.nationalpost.com/np/blogs/fullcomment/archive/2009/12/18/terence-corcoran-a-2-000-page-epic-of-science-and-skepticism-part-1.aspx and Part 2 here; http://network.nationalpost.com/np/blogs/fullcomment/archive/2009/12/18/terence-corcoran-a-2-000-page-epic-of-science-and-skepticism-part-2.aspx Climategate led me to Dr Trenberth's Aug09 paper "An imperative for climate change planning: tracking the Earth'd global energy budget" which has been oft quoted in this blog. Dr Trenberth's 'travesty' comment in the leaked emails caused advocates like Gavin Schmidt of RealClimate to publicise Dr Trenberth's paper as *already out there and not a secret at all*. This paper really opened my eyes to the state of play regarding AGW theory, modelling, measurement and the importance of the energy balance and OHC measurement; and the wide range of uncertainty in the various forcing components. So Climategate was not a waste of time, and it did expose the scientists involved as typically human with all the same vices as someone like Joe the Plumber.
114661. johnd at 22:49 PM on 24 July 2010
        The nature of authority
        shawnhet at 21:44 PM , that is what some scientists do consider to be the case, that is a decrease in cloud cover, even a very small decrease, causes the temperatures to rise, and conversely an increase in cloud cover causes temperatures to fall as a nett effect. Thus not being clouds that are responding to temperatures, but clouds determining temperatures. Given increased atmospheric water vapour content correlates with increased temperatures, and for water vapour to complete it's part of the hydrological cycle, it must change state from a gas to a liquid or a solid before returning to the surface, it follows that increased atmospheric water vapour should result in increased cloudiness, thus exerting an overall nett cooling effect. Compare the charts I posted earlier with temperatures over the same time span and see what conclusions can be drawn. The red/blue coloured chart showing the mean cloud amount over the different latitudes is interesting with perhaps the 1998 El-Nino able to be identified.
114662. shawnhet at 21:44 PM on 24 July 2010
        The nature of authority
        KR:"We're still discussing cause/effect regarding clouds and temperature. However, if cloud cover (a negative forcing) decreases with CO2 driven temperature increases (inverse relationship), then cloud level is a net positive feedback." Yes, I understand that, however, my point is that if cloud cover were decreasing for some other reason (e.g. a natural variation), then the fact that cloudiness decreased in conjunction with increased temps was merely coincidental and doesn't necessarily imply that this inverse relationship will hold up under other conditions(such as when natural variations are different). Cheers, :)
114663. Ned at 21:44 PM on 24 July 2010
        Rebutting skeptic arguments in a single line
        RSVP writes: It seems odd that a change of 1.36 ppm in one case should elevate temperatures one degree, and that it takes a 175 ppm in another case to do the same. The log(2) relationship only holds for a moderate range of CO2 concentrations (basically, earthlike conditions as opposed to very high (Venusian) or very low-CO2 conditions). I don't have a reference for this right at hand, but if you want to get picky about it we can probably find one (it was discussed a couple of months ago when Steve Goddard was busy misunderstanding the physics of the Venusian atmosphere). RSVP continues: What prevents a skeptic from assuming this is simply a tailored curve fit to back a theory? Maybe the assumption of dishonesty isn't actually a characteristic of skepticism? There are a century's worth of papers on experiments involving the radiative properties of CO2 listed at Ari's AGW Observer website.
114664. dorlomin at 21:36 PM on 24 July 2010
        Assessing global surface temperature reconstructions
        I think Steve Mosher has done a reconstruction.... dont see him on the list.
114665. David Horton at 21:28 PM on 24 July 2010
        Assessing global surface temperature reconstructions
        Yes Chris, good stuff. However I think your analogy breaks down - in the psychiatry case it sounds like the "skeptics" were right (partly right?) but for the wrong reasons. I don't think that counts. Other psychiatrists would have go there eventually for the right reasons. Also "implicit assumption of bad faith" - the problem is that while your psychiatrists may not have been acting in bad faith (though it sounds as if, like AGW deniers, they were acting from ideological beliefs) there is absolutely no doubt that many, perhaps 97 out of a 100 of the deniers are acting in bad faith. For reasons to do with ideology (a complex ideology) on the one hand and financial interest (one way or another) on the other hand. I think most of these ideologies break down in the face of deniaworld's massive attack on not just climate science but all science. The only analogy I think is close is the tobacco companies fight against restrictions ad regulations.
114666. Ned at 21:26 PM on 24 July 2010
        Assessing global surface temperature reconstructions
        One note -- Figure 6 shows the result of a great deal of work by Ron Broberg to develop a non-GHCN temperature data set based on the SYNOP/GSOD database of surface temperature reports. Nick Stokes used these data in his TempLS program. This is quite an interesting project, IMHO, and the comparison in figure 6 (from Nick's blog post) is rather impressive. I'd encourage interested readers to check out the posts about GSOD on Nick's and Ron's sites.
114667. Ned at 21:13 PM on 24 July 2010
        Assessing global surface temperature reconstructions
        Thanks for the kind words and helpful suggestions, everyone. I had looked into the JMA data set (briefly) but wasn't able to find a numerical version of the data in an easy-to-use format. I admit I didn't invest a lot of time in it. They do post a version of the full data set but it's in a fairly complicated and cryptic format. It probably is worth looking into further, however, since as apescape points out it uses some different sources and thus would nicely complement the others. chriscanaris, thank you for your long and thoughtful comment. I always enjoy reading your ideas and opinions here. The first half of your comment I agree with completely. Not knowing anything about psychiatry I found the second half fascinating, though I'll have to remain agnostic on the extent to which it's an analogy for the "science process" issues in AGW.
114668. Ned at 21:00 PM on 24 July 2010
        Assessing global surface temperature reconstructions
        GP Alldredge writes: Did I miss something? It appears to me that the post is focussing on global land+ocean anomaly. But the dataset referenced "CRUTEM" is from land-station data only. For land+ocean, you need "HadCRU". I used HADCRUT for the parts of the post that deal with land/ocean temperatures (figs 1 & 4) and CRUTEM for figure 3, which compares land-only temperatures. Figure 8 has both CRUTEM and HADCRUT in it (note the microscopic labels...). The original draft of this post had more detail on the reconstructions, including an explanation of CRUTEM vs HADCRUT, GISTEMP land-only vs land/ocean, etc. But it was getting absurdly long....
114669. RSVP at 20:15 PM on 24 July 2010
        Rebutting skeptic arguments in a single line
        It seems odd that a change of 1.36 ppm in one case should elevate temperatures one degree, and that it takes a 175 ppm in another case to do the same. What prevents a skeptic from assuming this is simply a tailored curve fit to back a theory?
114670. johnd at 18:49 PM on 24 July 2010
        Models are unreliable
        I am having a good chuckle at the discussion about "being good enough to be useful" The parliamentary inquiry last year into the long term weather forecasting capabilities of BOM and the CSIRO received a submission from the federal Department of Agriculture describing the current forecasts as too inaccurate for farmers to use, whilst the submission from the South Australian Farmers Federation described them more to the point as "less then useful". This confirmed that nothing has changed since a University of Melbourne study 5 years ago found the same situation then. However the good news was that if the government could provide "significant further investment" in super computers, reliable usable predictions may be available in at least 3 years, but possibly as far away as 7 seven years.
114671. chris1204 at 18:35 PM on 24 July 2010
        The nature of authority
        tobyjoyce @ 58 'My own feeling is that Hulme and people like Judy Curry are not really helping. There are some issues over which no compromise is possible.' I guess we have to part company here despite out mutual regard for Stephen Gould. It bears remembering that the IPCC is itself a 'compromise.' Once we lose the capacity to talk to one another in a civilised way, hopes for progress evaporate. In another setting, I've heard it often said that the role of the expert is to shed more light, not more heat (pun sort of half intended but the saying is genuine - not one I made up).
114672. Pete Ridley at 18:22 PM on 24 July 2010
        Models are unreliable
        Actually, ref, comment #195, please don’t make assumptions about my motives. You are completely wrong about me wanting to delay things. What I’m wanting to do, as hopefully most sceptics do, is my best to ensure that the climate change medicine dispensed by the politicians is not more damaging to humans than any natural or unnatural changes to the global climates. Until I am convinced that the medicine will not make things worse I will continue searching for a better understanding. At least there are some people here who are trying to help me get that better understanding, but you are not one of them. Tom (Dayton) ref. comment #207: I do read Realclimate articles and comments but always in a very sceptical manner because of the pedigree of the main contributors. I do like that quotation you gave - "I use the term validating not in the sense of ‘proving true’ (an impossibility), but in the sense of ‘being good enough to be useful’)” but the question is good enough to be useful for what? For me the validation of computer systems starts with the user requirements. Policy-makers (including politicians) are among the primary users of those climate models. There are others like environmentalists. I leave it to you to work out what “good enough to be useful” means. Must dash, as the boss is calling. Best regards, Pete Ridley
114673. Doug Bostrom at 17:04 PM on 24 July 2010
        What do you get when you put 100 climate scientists in a room?
        Gallopingcamel I'll stick with the opinion of the judge handling the case, that Gore's movie was "broadly accurate." Looking at the matter from a slightly different perspective, when you mistakenly cited a finding of dishonesty by the justice presiding over the case were you merely careless, or just ill-informed? I'm sure you did not intend dishonesty so we can eliminate that possibility straight off.
114674. chris1204 at 16:57 PM on 24 July 2010
        Assessing global surface temperature reconstructions
        'Over the past year, there has been quite a flurry of "do-it-yourself" temperature reconstructions by independent analysts, using either land-only or combined land-ocean data.' The striking aspect of these reconstructions is not only their similarity to peer reviewed work but also the origin of some in sources associated with 'scepticism.' I checked out the Jeff Id reconstruction which was done by RomanM and posted on Lucia's Blackboard. Lucia is described as a 'lukewarmer' on WUWT and seems to strive for balance from what I've seen of her site. Jeff Id is strongly sceptical and very politicised in his perspectives (hence I stopped visiting his site - far too much partisan baggage). I think the notion that the world is not showing an overall warming trend in recent decades simply can't be taken seriously. WUWT has shifted the argument to suggesting that the 1930s showed similar temperatures to today but alleges that temperatures have been subsequently 'adjusted.' The latter claim would be worth dissecting. Interestingly, the Japanese data set posted by apeescape shows a 1940 warming though it's substantially less than that of the last 30 years. At any rate, the bottom line is that not even WUWT is claiming the absence of a current warming trend even while alluding to some recent 'weather' events which seem counterintuitive to the 'consensus' (sea ice, record cold in South America, etc). However, its readership's responses are much less nuanced with comments on the lines of 'It's freezing down here' or references to AGW being a proxy for 'world government,' 'socialism,' and the like. Sometimes, someone responds with a bit of serious science but this is rare. WUWT's readership is thus far less sophisticated than its bloggers. The readership seems to be more interested in entrenching preconceived notions. The bloggers however do give an airing to questions which ought to be at least asked (even if the eventual outcome may often be rejection of the hypothesis by the scientific community). The readership on pro-consensus sites is much more sophisticated. I do however feel perturbed at times by the undercurrent of anger of some posters which I feel divides the world into 'them' and 'us.' Some may simply be people who do not suffer fools gladly - well, I do understand that - I react similarly to the 'hired guns' in my own field though I couch my written responses in far more polite language. Others, however, may I fear be similarly not wanting to engage with the real complexities. The problem with disengaging from the complexities is that it actually hinders scientific advancement. The '100 scientists' post included a couple of responses suggesting that the dissenting 3 scientists played an important role. I might illustrate this with an example from my own field. When I was a medical student and trainee psychiatrist, the prevailing explanation of illnesses such as schizophrenia and major depression was the 'monoamine' hypothesis. Basically, psychotropic medications all shared common mechanisms in respectively blocking or potentiating the activity of monoamine neurotransmitters (chemical messengers) such as dopamine blockade (in schizophrenia) or serotonin and/or noradrenaline potentiation at synapses (junctions between nerve cells). Schizophrenia was seen as a consequence of excess dopamine activity while depression as a consequence of serotonin/ noradrenaline insufficiency. Animal models, some in vivo studies in patients, and post mortem studies of patients lent support to the hypothesis (ie, multiple converging lines of evidence existed) even though no direct evidence of synaptic monoamine dysfunction was ever demonstrated. There was no question that our drugs worked reasonably well (though often with limited effect) and as best as we could tell only worked only if they affected synaptic neurotransmitters in specific ways. However, while the impact on synaptic neurotransmitter activity was demonstrably immediate, symptoms usually did not recede until at least two to six weeks of starting on the drugs. At the time, some contrarians debunked the monoamine hypotheses of depression and schizophrenia precisely because of this problem (and a whole lot of other issues besides - eg, depictions of psychiatric illness as no more than a social construct). The profession saw them as eccentrics and indeed they included in their number some seriously eccentric people. Because of the stigma around psychiatric illness, a significant body of patients often ended up with less access to treatment. The views of the contrarians fed the antipsychiatry movement which has had and to some extent still has a lot of traction. Nevertheless, a great deal of further research ensued and we now think that depression and schizophrenia have far more complex though still poorly understood origins. Much of the research implicates intracellular mechanisms as well as changes in neuronal connectivity in key brain areas ensuing over periods going from weeks to months and much more in keeping with real life trajectories of treatment response. We're hoping that this research will result in more sophisticated therapies (ie, more effective therapies that address the causes of these illnesses with significantly lower side effect burdens for patients) though so far nothing is on the horizon. The evidence base around the AWG hypothesis is arguably more robust than the evidence base around the neurobiology of psychiatric illness. Parallels however exist. We have an extraordinary knowledge explosion in brain function but much of this knowledge has not yet been integrated into a coherent synthesis. Neuroscience like climate science depends on a multiplicity of disciplines encompassing inter alia physicists. We have a similar knowledge explosion in climate science. My impression is that we may have a better synthesis in climate science than we do in neuroscience. However, treating the work of outliers with outright contempt runs the significant risk of demotivating folk who actually do want to look more closely at pieces in the jigsaw that don't quite fit (like some of the questions around cloud cover, feedbacks, and the like). Some of the folk currently interested in these areas may well be barking up the wrong tree. Maybe the bits of the jigsaw fit better than they think. However, angry dismissals of their work with the implicit assumption of bad faith add to the problem and don't contribute to solutions.
114675. Doug Bostrom at 16:09 PM on 24 July 2010
        Assessing global surface temperature reconstructions
        I've seen -some- of these examples cited in various places but never all together. This post ought to be be a mandatory checkpoint for sensible self-professed climate skeptics; going off the rails on a matter so unambiguously resolved will serve as a useful credibility diagnostic no skeptic will want to fail. One improvement I could think of would be to bring the external supporting material together under one roof so as to avoid "rot" of the links but I suppose there could be some permissions hurdles. Nice job, Ned.
114676. thingadonta at 16:00 PM on 24 July 2010
        The nature of authority
        "for there is only one right answer to any scientific problem, only one theory that is wholly correct." If something is a 'theory' it cant be 'wholly correct', by definition, and you can't use it in the same sentence. Your discussion and such wording shows you really don't have any idea on uncertainty and authority. Some scientific problems have no known 'right answer', because of fundamental uncertainty. And some people can't handle no 'right answer', or that there could be many partially 'correct' answers'. So they force a 'single answer', artifically, so to speak. Such is the political process, which sometimes also infuses science. The folowing is a very different perspective on 'authority'. The reason that teenagers are often naturally rebellious is because social authority is so often distorted that biology has selected rebellion and independance of thought in the developing mind as a way of dealing wih almost automatic distortion of knowledge/power in any social community, including within science. This is a totally different way of looking at authority and knowledge than you have described, and I'm glad that in the real world, biology deals with distortion of knowledge/power in a far more practial way than your discussion.
114677. GP Alldredge at 15:59 PM on 24 July 2010
        Assessing global surface temperature reconstructions
        Did I miss something? It appears to me that the post is focussing on global land+ocean anomaly. But the dataset referenced "CRUTEM" is from land-station data only. For land+ocean, you need "HadCRU".
114678. Philippe Chantreau at 15:53 PM on 24 July 2010
        The nature of authority
        Happy flying, KR :-) Have been away from the cockpit too long myself but still keep my instructor certificate current. I'll get back up soon, when the time is right.
114679. Philippe Chantreau at 15:49 PM on 24 July 2010
        Assessing global surface temperature reconstructions
        Nice work Ned.
114680. gp2 at 15:13 PM on 24 July 2010
        Assessing global surface temperature reconstructions
        There is also a third satellite temperature reconstruction that has substantially higher trend particularly in the tropics: http://www.star.nesdis.noaa.gov/smcd/emb/mscat/mscatmain.htm NOAA/nesdis do not provide TLT data but a discussion and comparison with other reconstruction is available in this paper: Zou et al 2009 ECMWF reanalysis data are available at knmi climate explorer: ecmwf reanalysis
114681. gallopingcamel at 14:59 PM on 24 July 2010
        What do you get when you put 100 climate scientists in a room?
        JMurphy (#122), Al Gore's "An Inconvenient Truth" has whoppers in great store but the few listed in the UK high court were more than sufficient to prove the plaintiff's case. It was the media that could not decide whether there were 9 howlers or 11. doug_bostrom argues that Al Gore was not dishonest. OK, so what words should we use to describe his errors? Would you prefer, careless, ill informed or scientifically illiterate? Even if Al Gore made honest mistakes when writing his book, his failure to 'fess up after being proven wrong in court was dishonest. Just like his old boss, he was incapable of admitting error even in the face of irrefutable evidence. How dare a mere truck driver challenge a member of the American "Ruling Class"?
114682. KeenOn350 at 14:22 PM on 24 July 2010
        Assessing global surface temperature reconstructions
        Very nice post Ned, thanks...
114683. diessoli at 13:38 PM on 24 July 2010
        Assessing global surface temperature reconstructions
        http://www.ecmwf.int/products/forecasts/d/inspect/catalog/research/eraclim/timon/timon_ana_2D!TLT!anom!Globe!195701-201012!/ ? D.
114684. KR at 13:27 PM on 24 July 2010
        The nature of authority
        shawnhet - as johnd and I were discussing above, global cloud coverage and temperature anomaly appear to be inversely related based on data over 1952-2008. johnd's satellite data (1983-2008) and the Warren 1988 paper (1952-1981) compared to the surface temperature records show this clearly. We're still discussing cause/effect regarding clouds and temperature. However, if cloud cover (a negative forcing) decreases with CO2 driven temperature increases (inverse relationship), then cloud level is a net positive feedback.
114685. johnd at 13:09 PM on 24 July 2010
        The nature of authority
        shawnhet at 12:13 PM, re "This doesn't have to be the case. As above, the temperature could rise, pumping more moisture into the air, causing more condensation and hence more cloudiness." That is what would appear most logical, but is only a portion of the whole process. More clouds result in a greater nett cooling effect, which is evidenced by the way periods of lower cloud coverage correlate with higher temperatures. This can be seen comparing the global cloud graphs above with global temperatures over the same time frame.
114686. Tom Dayton at 12:56 PM on 24 July 2010
        Models are unreliable
        Pete Ridley, since you are failing to understand the repeated explanations of how Hansen's model has been shown to successfully predict temperatures, you should read the more detailed posting at RealClimate, "Hansen's 1988 Projections." With regard to your more general confusions about models, you should go to RealClimate's Index, scroll down to the section "Climate Modelling," and read all of the posts listed there. For example, in the post "Is Climate Modelling Science?", there appears:

        "I use the term validating not in the sense of ‘proving true’ (an impossibility), but in the sense of ‘being good enough to be useful’). In essence, the validation must be done for the whole system if we are to have any confidence in the predictions about the whole system in the future. This validation is what most climate modellers spend almost all their time doing."

114687. Stu at 12:36 PM on 24 July 2010
        Assessing global surface temperature reconstructions
        "It is nasty to see this kind of conspiracy" Is what some so-called 'sceptics' might see in muoncounter's post. Anyway... I had a solid idea that the temp reconstructions were robust anyway given their agreement and consistency, and events over the last year have only reinforced this. But I was appalled by the behaviour of Watts and D'Aleo, claiming the dropouts enhanced warming. This was so amply proved false that it stopped being a sceptic talking point quite quickly, but I do occasionally remind people of it. As Ned says, D'Aleo and Watts are simply wrong.
114688. muoncounter at 12:15 PM on 24 July 2010
        What do you get when you put 100 climate scientists in a room?
        #114 and others: If you are looking for people legitimately concerned about 'Catastrophic Global Warming,' look here. How you define catastrophe depends on where you live: "climate change poses the most serious threat to our survival and viability, and, that it undermines our efforts to achieve sustainable development goals and threatens our very existence" "... there is an urgent need to consider and address the security implications and the human dimensions of climate change, including where necessary, initiatives for preparing communities for relocation." Seems like there was ample totally non-political evidence that where you live determines what you are concerned about -- back in 2005. Something about a 25 foot storm surge and a 17 foot levee = 8 feet of water overtop.
114689. shawnhet at 12:13 PM on 24 July 2010
        The nature of authority
        KR:"Clouds do have an immediate, local effect on temperatures. But what drives cloud formation in the first place? Relative humidity and atmospheric lapse rate, as I understand it. The bottom of a cumulus cloud is exactly where the relative humidity reaches 100% as the lapse rate drops temperature. And believe me, I follow those numbers quite closely as an aviator." It's true that cloudiness is driven by RH and lapse rate but it is also affected by absolute humidity too. The more water vapor in the air when it begins to condense, the bigger, thicker and more extensive the clouds that will be formed. One need only look at the tropics for confirmation here. johnd:"the inverse relationship of global cloud coverage to temperature should hold up well irrespective of which way cause and effect applies." This doesn't have to be the case. As above, the temperature could rise, pumping more moisture into the air, causing more condensation and hence more cloudiness. Cheers, :)
114690. muoncounter at 11:28 AM on 24 July 2010
        Assessing global surface temperature reconstructions
        Nicely done, Ned: Confidence in these temperatures can now be at an all time high! It is nice to see this kind of consistency. Take just about any of these graphs and fit a line from 1970 or so to today: you see a global temperature increase at a rate of 0.4-0.6 deg in less than 30-40 years. I can't wait to hear the "No, its not" chorus come chiming in.
114691. kdkd at 11:03 AM on 24 July 2010
        The nature of authority
        johnd #73 Your post confused me a bit. I think this is because you are getting positive feedback effects confused with runaway positive feedback effects. They're not the same thing. The water content of the atmosphere (a function of temperature and local environmental conditions) is the former. It certainly is not the latter, otherwise we would not be here.
114692. Doug Bostrom at 10:54 AM on 24 July 2010
        The nature of authority
        Regarding clouds, I thought I read somewhere that models indicate the role of clouds depends on their altitude. Dredging for something useful on that, I bumped into an exploration of the concept having to do with actual clouds and concerning the disappearance of real-world low level clouds leading to the appearance of high level clouds and thus leading to a net positive feedback. See this interesting article in Physics World. More here in Science Daily. Sorry I don't have time right now to follow up with anything later or more definitive. Food for discussion in the meantime...
114693. KR at 10:49 AM on 24 July 2010
        The nature of authority
        I agree on the inverse relationship, johnd - but we already have a known cause for temperature increase in the CO2 levels. That would seem to indicate that the decreased cloud levels are an effect via the inverse relationship, not a cause, unless they are (a) independently driven, and (b) the CO2 levels are not sufficient to drive the temperature changes, which doesn't seem to be the case.
114694. johnd at 10:19 AM on 24 July 2010
        The nature of authority
        KR at 10:05 AM, the inverse relationship of global cloud coverage to temperature should hold up well irrespective of which way cause and effect applies.
114695. KR at 10:05 AM on 24 July 2010
        The nature of authority
        johnd - excellent points on total water vapor vs. temperature. I will note, however, that increasing temperatures raise water vapor partial pressures, increasing the absolute humidity for the same values of relative humidity. And the GHE of water vapor is driven by absolute humidity. Clouds do have an immediate, local effect on temperatures. But what drives cloud formation in the first place? Relative humidity and atmospheric lapse rate, as I understand it. The bottom of a cumulus cloud is exactly where the relative humidity reaches 100% as the lapse rate drops temperature. And believe me, I follow those numbers quite closely as an aviator. As to the chicken/egg question of clouds and temperatures - the temperature increases are readily explained by the CO2 increases over the last 150 years with some positive feedback, and the global cloud cover appears to be inversely related to temperature in some fashion. Unless there's some mechanism independent of temperature that is changing global cloud coverage, I would think that the inverse relationship of global cloud coverage to temperature holds up pretty well.
114696. johnd at 09:45 AM on 24 July 2010
        The nature of authority
        KR at 09:09 AM, whilst the correlation stands up well, the real key is what drives the formation of clouds. If that turns out to be something other then clouds being driven by temperature, and it is clouds that instead are driving temperature, then that puts everything into a different perspective. Whilst the present consensus seems to be temperature driving clouds, it is a very fine line that is difficult to call decisively, but with very big implications to the whole understanding of the greenhouse effect. However, from an anecdotal point of view, most people who have spent a lifetime observing outdoors through all seasons, and longer term events such as droughts and flooding rains, would conclude most reasonably that it is definitely clouds that drive temperatures.
114697. Daved Green at 09:41 AM on 24 July 2010
        CO2 effect is saturated
        Thanks Ned After another hour of searching I found Science of Dooms response in another blog with a link to his ? blog .
114698. apeescape at 09:33 AM on 24 July 2010
        Assessing global surface temperature reconstructions
        Japan Meteorological Agency seems to have there own set of data. They use the "Kobe collection" (Ishii et al. 2004) for SST; for land temperatures, NCDC data is used till 2000, and CLIMAT messages are used from then on. Their data uses 1971 ~ 2000 as their baseline. Kooji Ishihara 2005 ~ COBE-SST を用いた全球平均気温の算出
114699. johnd at 09:26 AM on 24 July 2010
        The nature of authority
        kdkd at 08:36 AM, water vapour has a limited residency time in the atmosphere and can only complete it's cycle by the transformation to a liquid or ice. Thus it is reasonable to expect that as atmospheric water vapour content varies, so too would that of clouds. For water vapour to transform to liquid or ice, it has to give up all the heat that it had absorbed that was providing the positive feedback mentioned. If however it didn't give up all the heat, but retained some then that would maintain that positive feedback into the next cycle. HOWEVER, H2O is subject to meeting certain well defined conditions in order to change state, so about the only thing that can vary is the rate that H2O progresses through the cycle, which is probably linked to the frequency and intensity of such events as El-Nino and other similar events which each have their own identified cycles that change over much longer time frames, 6 or 7 decades, or even longer. The Quinn El-Nino reconstruction is interesting showing periods of greater and lesser activity and intensity over such longer time frames.
114700. KR at 09:09 AM on 24 July 2010
        The nature of authority
        johnd - As I noted here, no cloud trend over a no temperature change region - I was careless in my first look and didn't directly correlate the two. Over the 1952-1981 period clouds and temps hold pretty steady, based on ship-borne recorded cloud observations. Over the 1983-2008 period you gave data for, there appears to be an inverse relationship between temperature and global cloud coverage. If increased clouds provide a cooling effect, the data we have seems to indicate that cloud formation (negative) with temperature (positive) means that inverse cloud levels provide a positive feedback on temperature changes. Not bad - we're up to 56 years of data, with a two year gap. I don't have the raw data assembled for the Warren paper, or yours, so I can't run a statistical analysis on the trend relationship. But it's a pretty good inverse match from eye-balling it; enough to perhaps make it worthwhile to analyze the stats. Try this direct link for the Warren paper. My first link was through a citation, and might have been problematic.

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