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Comments 1 to 50 out of 116:

1. Jim Powell at 01:10 AM on 13 May, 2011
   Another difference is that Galileo did not have tenure to protect him. One false move and the Roman Inquisition would have put him to the stake.
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2. Chris G at 01:25 AM on 13 May, 2011
   Thanks Dana, this is the best summary I've yet seen to counter with when someone uses Lindzen in an appeal to authority argument. The one critique I have is that I gathered on the prior post in this series that Lindzen postulates a lower sensitivity to CO2 levels than to orbital changes. I would like to see a treatment of that if you have time. My first thoughts on the matter are that orbital forcings are initiated by albedo changes, and we have already seen large albedo changes as a result of CO2 induced warming. So, if I am correct, again, there is actual evidence that counters Lindzen's model of the world. Although, I don't know if the albedo changes we have already seen are greater or larger than Milankovitch cycle induced changes. I also recall reading that, from a mathematical perspective, the amount of forcing that an M. cycle produces is smaller than the W/m^2 forcing that some level of increased CO2 produces. That could be another tack to take. Thanks Again.
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3. Chris G at 01:26 AM on 13 May, 2011
   greater or _less_*, oops
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4. dana1981 at 01:37 AM on 13 May, 2011
   Thanks, Chris.

   "Lindzen postulates a lower sensitivity to CO2 levels than to orbital changes."

   This may be true (because otherwise it's extremely difficult to explain glacial-interglacial transitions with low sensitivity to CO2), but has Lindzen ever come out and said it? It would require some research into the magnitude of the orbital forcing to address this. I'd also like to mention that I emailed Dr. Lindzen to offer him the chance to respond to the Lindzen Illusions series.
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5. Chris G at 01:45 AM on 13 May, 2011
   Hey Dana, I think there are good odds of it being in Lindzen, R. S.: 1993, 'Paleoclimate Sensitivity', Nature 363, 25-26. But, I suspect getting a copy of that will require a subscription to Nature or access to a university library that I don't currently have.
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6. les at 02:39 AM on 13 May, 2011
   Great summary. I'd like to add a couple of other fators which, I think, come into these kinds of discussion. 1/ selection bias. As you say, Galileo was right - we know that to the n^th degree with hindsight. But there have been many - often brilliant - scientists who've made wrong 'strong' assertions. How does one know, for someone makeing strong and public claims, that theyre like Galileo and not, for example, like Eric Laithwaite? I superb chap, who, for years, held onto the belief that gyroscopes violate Newtons laws. Or like the late Freddy Hoyle a giant amongst cosmologists, who never really gave up on the expansionary universe? I'm not going to get into lists ;), but I'd not be surprised if there where more cleaver chaps who held out for wrong ideas than ones who struck gold! 2/ The second point is that it is not unusual for people to hold onto wrong beliefs when the benefit of doing so - e.g. lime-light, a following etc - is greater than the detriments - e.g. looking daft to other people. This point was called "being strategically wrong" as analysed by Robert Kurzban in "Why Everyone (Else) Is a Hypocrite: Evolution and the Modular Mind By" in which he noted that Stephen Jay Gould - who we all know and love - sustained a completely ill founded assault on evolutionary psychology for many years, despite criticisms, not only from them, but from his own! This is a good read. I remind people of Poptech... the value of his list - his fame, 'voice', internet-presence etc. not only depended on the list but the list being wrong and, therefor, the arguments it generated. It was in his best interest for the list to be wrong! A good list summarizing the number of papers published supporting AGW to a greater or less degree, or even a better use of statistics or clearer analysis (as we all suggested)... would not have brought him any fame and attention, upon which he thrived!
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7. chris at 02:52 AM on 13 May, 2011
   Chris G @5; yes he sort of says it in that letter to Nature you refer to (which is a response to a Hoffert and Covey paper describing a calculation of a value for climate sensitivity (2.3 oC per doubling of CO2)[*]). Lindzen asserts that temperature changes are dominated by changes in the nature of heat transport (air and oceans), and suggests that Milankovitch cycles, which themselves result in very minor changes in total insolation, are amplified by changes in this heat transport. Referring to these heat transport processes as "dynamic fluxes" Lindzen says:

   "Dynamic fluxes depend on motions which in turn depend on spatial variations in heating. Thus, orbital variations are believed to have caused the cyclic glaciations of the past 700,000 yr (the Milankovitch hypothesis(6)). These variations involve very small changes in globally and anually averaged insolation, but give rise to major changes in the distribution of heating.".

   He states that atmospheric heat fluxes depend on Hadley circulation in the tropics, which

   "depends on the displacement of the zonally averaged summer surface temperature maximum from the equator, and on the medidonal sharpness of the zonally averaged temperature maximum. The former is extremely sensitive to orbital parameters, whereas the latter greatly depend on the nature of monsoons...... Lindzen states: "Incidentally neither of these two factors depends significantly on gross radiative parameters like CO2 concentration or spolar constant - at least within the range of variation considered in ref 1" (which is [*} below)

   In other words Lindzen is asserting that the Milankovitch cycles and their effects on glacial-interglacial series are amplified by heat transport changes, and these don't need any significant contribution from radiative forcing from variations in [CO2]. He states:

   "In particular, if an altered distribution of heating produces a large change in synamic heat flux, then major changes in global climate may occur, even if the sensitivity to changing CO2 is extremely small"

   Hoffert and Covey are pretty robust in their response! * Martin I. Hoffert, Curt Covey (1993)Palaeoclimate sensitivity Nature 363, 26-26.
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8. Albatross at 03:06 AM on 13 May, 2011
   Chris, That is a pretty mind boggling hypothesis by Lindzen! I have not read Hoffert and Covey's Only tiny external forcing to set off huge global warming/cooling without the aid of a CO2 feedback? Does he at least accept the feedback from changes in albedo? I have a major problem with his hypothesis, how the heck does the redistribution of a tiny increase of energy amplify the warming. Surely the additional heat is just redistributed by these meridional fluxes? This seems to be the same logical fallacy that internal climate oscillations are driving long-term trends. His hypothesis may , at best, describe long-term regional changes in temperature, but not long-term global trends. Anyways, I am probably missing some even more disturbing issues, but that is all that came to mind off the top of my head.
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9. ClimateWatcher at 03:55 AM on 13 May, 2011
   Richard Lindzen is one of the most prominent and widely-referenced climate scientist "skeptics". After all, there is a scientific consensus about anthropogenic global warming You should probably add that Richard Lindzen is part of that consensus - his published works indicate AGW due to CO2.
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10. chris at 04:02 AM on 13 May, 2011
    yes, very strange, Albatross; it's astonishing that Dr. Lindzen has been pulling this stuff out of the hat for the better part of 20 years. Perhaps at some point it could have been described as provocative, but it seems a little more disagreeable than that nowadays. The response to Lindzen's critique (that I quote from) of Hoffert and Covey's paper (whch was in fact published in 1992, and not 1993 as in my post above), by Hoffert and Covey is very interesting. It pretty much tears apart Lindzen's conjecture, and is astonishingly modern; it could have been written yesterday, and gives a pretty up to date account of energy balance, ice age cycles and radiative forcing. Incidentally Hoffert and Covey's original paper cited in my post above, refers to another of Lindzen's subsequently falsified assertions; Hoffert and Covey say:

    "Lindzen(13) holds that GCMs err on this point and that water vapour feedback is in fact negative (deltaQclear/deltaT is less than 0, because tropical cumulus towers enhanced by glonal warming dry the upper troposphere enough to reduce infrared opacity worldwide)."

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11. ClimateWatcher at 04:06 AM on 13 May, 2011
    The water vapor feedback is negative ... Indeed, recent observational evidence has been consistent with the climate model projection of a strongly positive water vapor feedback. The sonde data disagree. And, so do observations of emissions. The water vapor channels from satellites depict the energy at which water vapor emits to space. Spatially anyway, the highest levels of water vapor emission are from the sub-tropics. The dynamics ( who'd have thought, dyanmics? ) of subsidence account for this, of course, but spatially, if one looks at regions excluding high clouds ( which are far more important radiatively than gasses ), then higher surface temperatures correspond to greater emissions from water vapor. Lower surface temperatures correspond to lower emissions from water vapor. The correlation is less than with the window emissions or with the wings of CO2 emissions, but this is negative feedback.
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12. chris at 04:25 AM on 13 May, 2011
    ClimateWatcher, the radiosonde reanalysis data is very problematic as has been known for long time [*]. What radiosonde data were you thinking of? There is loads of data from satellites that indicates an increase in upper troposphere water content pretty much as expected from enhanced greenhouse induced tropospheric warming. See for example: Dessler, A. E., Z. Zhang, and P. Yang (2008), Water-vapor climate feedback inferred from climate fluctuations, 2003–2008 Geophys. Res. Lett., 35, L20704 here Gettelman A and Fu, Q. (2008) Observed and simulated upper-tropospheric water vapor feedback J. Climate 21, 3282-3289 here Buehler SA (2008) An upper tropospheric humidity data set from operational satellite microwave data J. Geophys. Res. 113, art #D14110 here Brogniez H and Pierrehumbert RT (2007) Intercomparison of tropical tropospheric humidity in GCMs with AMSU-B water vapor data. Geophys. Res. Lett. 34, art #L17912 here Santer BD et al. (2007) Identification of human-induced changes in atmospheric moisture content. Proc. Natl. Acad. Sci. USA 104, 15248-15253 here [*] Soden BJ, et al (2005) The radiative signature of upper tropospheric moistening Science 310, 841-844. here who state: “Although an international network of weather balloons has carried water vapor sensors for more than half a century, changes in instrumentation and poor calibration make such sensors unsuitable for detecting trends in upper tropospheric water vapor (27). Similarly, global reanalysis products also suffer from spurious variability and trends related to changes in data quality and data coverage (24)."
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13. Pete Dunkelberg at 04:27 AM on 13 May, 2011
    Statistics show that most people who think they are Galileo are mistaken.
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14. Chris G at 04:33 AM on 13 May, 2011
    FWIW, I think I connected the wrong dots. Covey references Lindzen (1993), which I took to be an actual article with particulars, where he meant the same discussion piece that dankd linked in Lindzen #4. I suspect another, possibly more important piece of work, for this discussion, is referenced by Covey as Kirk-Davidoff, D. B. and Lindzen, R. S.: 1993, Paper presented at the American Geophysical Union annual Fall .Meeting, San Francisco, CA. which might also be known as Kirk-Davidoff, D.B., and R.S. Lindzen, 1993: On the Role of Meridional Energy Fluxes in Climate Change. Oral Presentation, Fall Meeting of the American Geophysical Union. http://www.atmos.umd.edu/~dankd/CV.pdf I have not found a publication of that paper by the same name. I'm wondering if dankd the poster here is Daniel Kirk-Davidhoff, the primary author of the paper above, and if so, if he could shed some light on the different mechanics between orbital and GHG forcings.
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15. les at 04:40 AM on 13 May, 2011
    History shows that at least one person who thought hes was Galilao was right. It follows that "it is possible for someone who thinks they are Galilao to be right." from which we derive "not all people who think they are Galilao are mistaken". Any good? (I'm sitting for my Clinate "skeptic" exams. Think I'll pass?)
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16. Chris G at 05:02 AM on 13 May, 2011
    Les, Not that it matters, but I think the odds are against it. As for your reference to Poptech's list, I'll admit to some curiosity about it, but he lost me when he claimed to have a better understanding of what some papers mean than the persons who wrote them.
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17. chris at 05:06 AM on 13 May, 2011
    Here's a copy of the Nature letter (by Dr. Lindzen) and response (by Drs Hoffert and Covey) I excerpted from in my post @7 above. The Hoffert/Covey response is very good...
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18. Chris G at 05:08 AM on 13 May, 2011
    Les, on second, read, I think I misunderstood your point on the first go. Please disregard my last comment.
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19. Chris G at 05:11 AM on 13 May, 2011
    Back on Lindzen, it is a curious thing that someone whose own model of how climate works is full of incorrect premises should spend so much time criticizing the models used by the IPCC.
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20. les at 05:26 AM on 13 May, 2011
    Chris G 16 - yes the odds are against it, but the cost of believing you're Galileo is small (is you do do quiet to your self) and the payoff is high is you are right. Well worth it! 19 - yes, it is curious and fascinating...
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21. dana1981 at 05:38 AM on 13 May, 2011
    chris #17 - interesting letter, thanks for the link.
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22. ClimateWatcher at 05:53 AM on 13 May, 2011
    #12 There are problems with satellite estimates of humidity also: (see slide 15 for contradictory trends between two satellites ) As to RAOB, I'm sure you're familiar with the Paltridge paper There are problems with sonde data, notably spatial coverage and instrumentation change. But even in recent decades, as the instrumentation has become more uniform, the sonde data do not show positive feedback. One should also look further. People assume that when humidity increases, infrared emission to space decreases. But we observe the opposite. Excluding cloudy areas, the moist subtropics emit more to space than do the dry polar regions. It is temperature and vertical variation of humidity that govern earth's emission amount and not to total water vapor. Make the world more like the subtropics and it will cool off because it will emit more energy to space. Make the world more like the polar regions and it will warm up because it will emit less energy to space.
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23. Bob Lacatena at 06:06 AM on 13 May, 2011
    22, ClimateWatcher, I can't believe anyone would still put forward the Partridge paper as evidence/argument for anything.
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24. chris at 06:24 AM on 13 May, 2011
    ClimateWatcher, your assertion that "But even in recent decades, as the instrumentation has become more uniform, the sonde data do not show positive feedback", isn't true. For example, the radiosonde reanalysis of McCarthy et al (2009) does show a positive water vapour response to tropospheric warming. Likewise the reanalyses described by Dessler and Davis (2010). Likewise with the new radiosonde analyses described in Dai et al. (2011). Paltridge et al is not a particularly convincing example for your argument. After all the authors themselves conclude:

    "It is of course possible that the observed humidity trends from the NCEP data are simply the result of problems with the instrumentation and operation of the global radiosonde network from which the data are derived."

    I don't think one can dismiss the very large body of work from satellites and now from raiosonde reanalysis that global warming is accompanied (amplified) by enhanced tropospheric water vapour.
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25. KR at 07:13 AM on 13 May, 2011
    ClimateWatcher - "Make the world more like the subtropics and it will cool off because it will emit more energy to space. Make the world more like the polar regions and it will warm up because it will emit less energy to space. " This is one of the more outrageous statements you've made. You are, I hope, aware of the T^4 relationship between temperature and power emitted? Of course the tropics emit more energy, they are warmer! I would rather not turn the polar regions into tropics, myself - it would have rather harsh consequences for the middle latitudes, let alone the present tropics. Moist air emits less energy than dry air at any particular temperature, ClimateWatcher. Predicted, tested, proven.
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26. Chris G at 08:15 AM on 13 May, 2011
    @Dana 21, Just to connect some dots, that is the same link posted by dankd, whom I suspect is the same climate researcher who studied under Lindzen as a graduate student about the time that the 1993 discussion and unpublished AGU presentation were written. So, I suspect that Dan has a better understanding of what Lindzen's views are, or were, than anyone other than Lindzen himself. Which makes the AGU presentation, where he is the primary author and Lindzen the second, interesting.
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27. ~Qt~ at 09:38 AM on 13 May, 2011
    @ Climate Watcher 22 Paltridge et al. found that specific humidity in the NCEP/NCAR reanalysis declined between 1973 and 2007. However, this reanalysis is incredibly biased and almost certainly inaccurate for several reasons. 1) Other reanalyses indicate that the long-term water vapor feedback is positive, as chris noted. 2)The NCEP/NCAR reanalysis was solely dependent on radiosonde humidity measurements to constrain upper tropospheric humidity. As you note, there are problems with these measurements. 3) While the NCEP/NCAR reanalysis showed that the long-term water vapor feedback is negative, it also indicated that the short-term feedback is positive. This makes very little physical sense. 4) Newer reanalyses include improvements that are designed to increase the fidelity of long-term trends. Thus, the NCEP/NCAR reanalysis is not as accurate as the newer reanalyses which indicate the existence of a positive feedback.
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28. ~Qt~ at 09:42 AM on 13 May, 2011
    I meant to include this link with my previous post: Dessler and Davis (2010) - full paper
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29. ~Qt~ at 09:47 AM on 13 May, 2011
    By the way, I love the Lindzen's Illusions button!!!
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30. Same Ordinary Fool at 12:55 PM on 13 May, 2011
    The primary difference between Galileo and Lindzen is that Galileo was at the front edge of new discoveries. People who don't know what he found still remember that he was persecuted for publishing something new. On the other hand, Lindzen is at the rump end in the march of climate science. Fifty-sixty years ago, his no-significant-CO2-effect position was the consensus position among climate scientists. It has since declined to only 3% (or 1%, with 2% don't know). This distinction is of obvious interest to those who don't know much climate science, and are looking for other indications of validity. Those who would champion Richard Lindzen need to find another analog. In the history of science are there any examples of scientific positions that have declined to 3% participation, yet eventually prevailed?
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31. RSVP at 15:12 PM on 13 May, 2011
    "Those who would champion Richard Lindzen need to find another analog" Copernicus or Ohm might do. The sad part being that their "being right" was only received recognized after they died. http://en.wikipedia.org/wiki/Georg_Ohm
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32. RSVP at 15:15 PM on 13 May, 2011
    An analog much harder to find is a mob that admits its mistake.
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33. actually thoughtful at 16:54 PM on 13 May, 2011
    All of us who used fossil fuel for most of our lives and now admit it was wrong and are working to stop it are quite a powerful mob. I predict that the next El Nino will trigger the climate change policy changes we need. Dana - this is a GREAT article. Thank you. I really like the what he said then, what he says now, and where is right and wrong setup. It feels much fairer than the original - tear apart his 1989 positions.
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    Response:

    [dana1981] Thanks!

34. les at 18:47 PM on 13 May, 2011
    31. RSVP Indeed (ignoring the fact that Ohm is a pretty poor example of controversy in science!) ... Again the point is that history contains examples of people who swam against the tide - some where right, some wrong, some right about some things and wrong about others (which includes Newton and Einstein), some recognized as right before they died, others after, others where just plain wrong... You have to justify - over and above "doesn't agree with the consensus" - why you think X is like Y, and justify it against the relevant history of science. Just saying "The maverick in science is often correct" without the justification is gibberish or propaganda... As I mentioned above, Laithwaite was, to some degree, "The maverick in science is often incorrect"... Why isn't he like that?!?!? Of course, for people who aren't used to doing a careful analysis and argument, such throwaway lines come naturally (see the blog links in the above article). I'd hope that SkS commentators would function at a higher level.
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35. alan_marshall at 19:12 PM on 13 May, 2011
    Galileo had to do deal with the skeptics of his age. He parodied them in his “Dialogue” by putting their arguments in the mouth of a character he called Simplicio. Galileo put his own life in danger because he would not deny the evidence of his eyes. Lindzen is not a Galileo, but rather a Simplicio.
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36. chris at 19:20 PM on 13 May, 2011
    RSVP "An analog much harder to find is a mob that admits its mistake. You're being a little hard on the likes of Drs Lindzen (and e.g. Spencer and Christy). I wouldn't call them a "mob" even if their actions are rather ill-considered. Perhaps you meant that they have a tendency to incite "mobs"! Maybe a bit of British-style kettling would be in order.... Actually Drs Spencer and Christy didn't so much "admit their mistakes" as have them pointed out in a manner that was impossible to deny (see pages 972/3).
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37. Phil at 20:39 PM on 13 May, 2011
    les @31 Just saying "The maverick in science is often correct" without the justification is gibberish or propaganda... You could say "the Maverick in science who is correct is more often remembered by posterity than the maverick who is wrong".
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38. Phil at 20:40 PM on 13 May, 2011
    Oops sorry. les was @34 not @31
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39. Camburn at 21:44 PM on 13 May, 2011
    Does Alfred Wegener come to mind....and he is very recent.
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40. chris at 22:32 PM on 13 May, 2011
    Wegener is an interesting example. Of course he's not an "analog" for Lindzen since Wegener followed his scientific heart honestly (and of course turned out to be correct - but also a little incorrect too), whereas Dr. Lindzen knowingly misinterprets the science and presumably has rather sadly lost the impulse to make real discoveries that all young scientists (and most not-so-young ones!) have. Every individual and their circumstances and social/scientific environment is different. So Wegener's studies were done at a time when there was neither a particularly strong scientific imperative to address the apparent physical, geological and environmental relationships between several adjacent continental margins, nor any political imperative whatsoever to do so. And whereas Wegener's ideas were right in essence (those inter-continental margin relationships were real and the result of actual juxtapositions in the deep past), Wegener couldn't propose any sort of realistic mechanism, and this differs from the situation today, re the evidence base that informs us on climate change, and the false evidence base that drives Lindzen-style analyses. Wegener's mechanistic proposals were rightly rejected (he suggested that the continents might be driven through the oceanic crust under the gravitational influence of the moon, for example). And he was inherently incorrect in that continents don't "drift". Rather they "piggy-back" on the plates to which they are very firmly attached....
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41. chris at 22:44 PM on 13 May, 2011
    In fact what I just wrote isn't fully fair. Dr. Lindzen continues to publish basic research on atmospheric physics, and presumably does retain the imperative to find stuff out. Perhaps it's fairer to state that he seems able to compartmentalize his science-science from his science-politics...
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42. les at 23:06 PM on 13 May, 2011
    40 chris - or, is Wagner a good analogy for Hansen, Broecker et al? Lets say the first firm indications for AGW piled up between the mid 70's and late 80's based on very rudimentary measurements compared to what's available today. I recall that even in the early 90's many scientists in associated fields where still unsure (in my direct experience, the European earth-observation crowd where still 'more measurement needed' in the mid 90's), till now where there is pretty broad based consensus, except for a few stragglers in the science community... ... and a pile of nutters in the public sphere, of course.
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43. chris at 23:23 PM on 13 May, 2011
    Yes, that works a bit better les! But again the analogies aren't terribly strong (and it's very easy with the compression of nearly a century of time to look at the Wegener situation as if it was very cut and dried, whereas it was also a mess of personal, social and scientific interactions, just like now). Whereas it seems that Wegener's ideas were soundly rejected at the time (in fact he had some supporters who were very important in geology/geophysics), and he was only vindicated after his death when new discoveries forced reassessment of his ideas, Hansen and Broecker were reinforcing an already quite well understood subject. Their insight was to strongly grasp the significance of the growing atmospheric CO2 levels, in the 1970's (Broecker) and 80's (Hansen), and to foresee the likely future consequences. And their contributions were not so much ignored/ridiculed, as considered not to be terribly important (at the time; I think that's about right). In fact their attempted ridicule (largely Hansen) occurred considerably later when the evidence base concerning the consequences of enhanced greenhouse gas levels became sufficiently strong, that some powerful interest became concerned that steps might be taken to do something about the problem...
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44. RSVP at 23:35 PM on 13 May, 2011
    les 34 "ignoring the fact that Ohm is a pretty poor example of controversy in science" Considering that "Ohm's Law" was rejected for being too simple, and then turned out to be spot on, not sure where you're coming from. Here is another link: http://www.corrosion-doctors.org/Biographies/OhmBio.htm
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45. les at 00:52 AM on 14 May, 2011
    44 - RSVP sure, but he's not considered a classic example. Still, if you like; I'm not fussed about that, I'm fussed about the justification of the comparison based on history if science etc. Clearly the simplicity of ohms law isn't that - there's nothing nearly as simple about climate science! So, we're still awaiting your detailed justification for your suggestion.
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46. les at 01:01 AM on 14 May, 2011
    43 - Chris Excellent! Although maybe you being less then generous to the substantial improvements in climate systems simulations, models etc. I'd love to see an equally detailed [attempt at a] comparison between Galilao and Lindzen! Of course no such comparisons work in all details. Still, such details provede more insight than a the sort of thin posted on wuwt etc.
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47. owl905 at 02:08 AM on 14 May, 2011
    Interesting sideshow - Galileo is popularized as a science rebel martyred by religion (which Lintzen is not). But historically, Galileo's 'crime' with the Church was the re-interpretation of scripture (which Ricky MIT most definitely is). If Lintzen's last name wasn't MIT, who would pay attention to him?
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48. Camburn at 03:41 AM on 14 May, 2011
    les@46: I had not been to wuwt in ages, but as a result of your post I went there. Bob Tisdale has an excellent post on OHC verses a model. I read what Tamino posted, and will only say that he degrades himself in his response. There is a def divergence, at this time, between observations of OHC and the models.
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49. dana1981 at 03:47 AM on 14 May, 2011

    "Bob Tisdale has an excellent post"

    Don't hear those words very often :-)

    "I read what Tamino posted, and will only say that he degrades himself in his response"

    I wouldn't call pointing out a textbook example of cherrypicking "degrading oneself". However, this discussion is off topic. Please stick to the content of the article.
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50. ClimateWatcher at 04:00 AM on 14 May, 2011
    1. Earth hasn't warmed as much as expected Trends since 1979 are all below the IPCC "low scenario" rate. Trends since 2000 are all below the IPCC ".2 C per decade for all scenarios" rate. One for Lindzen. 2. the surface temperature record is wrong SST and MSU are pretty close to land rates ( except for the high outlier GISS ) UHI effect does exist, but it is not a huge part of the temperature averages. 3. global warming is not a concern Concern reflects emotion, not a scientific quantity. But we know the recent rate is quite similar to the early twentieth century rate. We know that Northern Hemisphere temperatures were higher for millenia during the Holocene Climatic Optimum, a time which corresponded to the advancement of human civlization. And we know that humans and all the other species of life on earth evolved through all the glacial/stadial changes. Pretty hard to get worked up about this when there are so many real problems to be concerned about. 4. climate sensitivity is low Well, the lower warming rate from 1. indicates this to be true. But nobody can be sure. Why? Because we don't know how much energy earth is receiving, mostly because we don't know how much the earth reflects away: And we don't know how much earth is emitting: The uncertainty in the balance is larger than the projected forcing from a CO2 doubling. 5. the water vapor feedback is negative There are reasons to believe this to be so. There is great uncertainty as to whether or not water vapor is increasing or decreasing ( the sonde data indicate drying aloft, but are subject to instrumentation changes over time, some satellites indicate increasing, some indicate decreasing humidity ) But beyond that, water vapor is a dynamic quantity. It gets pushed around in the atmosphere, mostly pushed toward the equator by polar air masses. And water vapor, by its mere presence, works against an increase. That's because if water vapor injects into the upper atmosphere, which was previously arid, that region of atmosphere then radiates more effectively and cools. This cooling allows subsidence to occur. And subsidence then dries this layer. The total column water vapor might increase, but the top of this layer would emit just as effectively as with a lower total column water vapor. 6. the cloud feedback is negative Since the meager attempts to create a long term trend of cloudiness disagree in sign ( some indicate increasing cloudiness, others indicate decreasing cloudiness ) I don't think anyone can justify a conclusion on what has actually happened. And since cloud formation depends on some many processes from the macro ( synoptic scale convergence ) to the micro ( condensation nuclei ) and in between, I have a difficult time with any theory predicting any change in cloudiness. 7. global warming is just due to internal variability Since we don't actually know the energy balance well enough ( see above ) pretty much all attribution is a fairy tale. On the other hand, look at the 97-98 El Nino. Temperatures changed by almost 1 degree C, but oceanic heat content didn't show a pimple. This was internal variability. The warming rate from 1910 through 1945 is about the same as the recent rate. And that was natural variability. 8. water vapor is the most important greenhouse gas CO2 is significant, largely because of the band from which emissions to space leave from the stratosphere. That's a big deal because that makes the energy level that leaves from CO2 much lower and mostly (though not completely) independent of the surface temperature. H2O vapor, on the other hand, diminishes with height. It is the vertical variation of temperature coupled with the vertical variation of the emitting constituent that determines the energy that leaves earth. In this regard, forcing from water vapor is constrained and coupled to the surface temperature while CO2 emissions are not, and in this way CO2 is more 'important'. On the amount of 'greenhouse effect', my understanding is the relative importance goes: Clouds > Water Vapor > CO2 The question of 'importance', we might agree, is secondary to what will actually happen with changes in CO2.
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