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  1. Curry’s problem with the definition of “most” reminds me of Bill Clinton’s “It depends on what the meaning of the word ‘is’ is.”

    Comment by Jerry Steffens — 29 Jan 2012 @ 11:55 AM

  2. It’s quite telling that C&W avoided quantifying any of their assertions about probability/uncertainty in their BAMS paper (or in other opinion pieces, as James Annan pointed out).

    But hey, they threw in a few fancy quotes – from Box, G.B. Shaw, Lewis Carroll and Nietzsche no less!

    Comment by Former Skeptic — 29 Jan 2012 @ 12:44 PM

  3. If a car was speeding toward a cliff with a severed brake line, the driver stepped on the brakes and the car didn’t stop, what would be Judith Curry’s assigned likelihood that the car went over the cliff because the brakes didn’t work?

    Comment by Tim Jones — 29 Jan 2012 @ 12:54 PM

  4. I have been fascinated by the unfettered responses in Curry’s blog. I wonder if she has ever explained why she almost never responds to comments on her site that are totally beyond even her purportedly ambivalent approach, whereas she is often right on top of any exaggeration of comments that support ACC.
    At first I thought that maybe she was taking a pedagogic approach, allowing people to express their opinions and thinking the openness would allow reasonable examination of evidence to rise to the top. After a few years of this clearly not happening, she doesn’t appear to be interested in her site developing an accurate perspective.
    My limited view is that either naively, or for ideological reasons neither her nor Pilke Jr. are willing to accept that there is a rigid mentality among ideologues that does not allow them to modify their views regardless of the mass of evidence against them. Change often comes through a radical reassessment and a bounce to the opposite side. For instance former marxists becoming neocons, or extremely religious becoming hedonist atheists.
    to me the pretty easily varifiable observation – that many denialists consider climate scientists the enemy and as such not part of a rational dialogue, make having blogs such as Curry’s and Pilke’s rather meaningless.
    On the other hand I have learned a lot from their sites and even extreme denialist sites because I have had to search for information in places like RC that I otherwise would not have done.

    Comment by Tonydunc — 29 Jan 2012 @ 2:12 PM

  5. It must be very frustrating for you, professors, that you must engage in two debates: the public “debate” and the genuine one. This has been said before many times, but to reiterate, thank you.
    AR4 is five years old. Why attack it now? To provide a priori justification for similar criticism of AR5?

    Comment by One Anonymous Bloke — 29 Jan 2012 @ 2:16 PM

  6. AR4 is five years old. Why attack it now? To provide a priori justification for similar criticism of AR5?

    I think it’s an effort to change the content of AR5 … not just Curry et al but calls for change in process, etc.

    Comment by dhogaza — 29 Jan 2012 @ 2:36 PM

  7. (1) “(i) to the greatest or highest degree often used with an adjective or adverb to form the superlative (ii) to a very great degree” — Webster’s Ninth Collegiate Dictionary
    (2) “in the greatest quantity, amount, measure, degree, or number” — American College Dictionary
    (3) “with reference to amount or degree. as a superlative of comparison: greatest in degree or extent… .” — Compact Edition, Oxford English Dictionary.

    I don’t know how good scientist Dr. Curry is but her lack understanding of the English language is abysmal (“immeasurably low or wretched” –Webster)! Her papers must be a real joy to read.

    Comment by Bill — 29 Jan 2012 @ 2:41 PM

  8. Curry is, as usual, barking up the wrong tree.

    ‘most’ is not as important as ‘very likely’ which is defined in AR4 as ‘Confidence Interval’ => 90% if I recall properly.

    Comment by John P. Reisman (OSS Foundation) — 29 Jan 2012 @ 2:52 PM

  9. Just looked it up: ‘very likley’ > 90% probability

    IPCC AR4 Uncertainty Guidance, pg 4

    Comment by John P. Reisman (OSS Foundation) — 29 Jan 2012 @ 3:26 PM

  10. Curry believes it is possible there could be global cooling over the next decades – say 20 to 30 years.

    [Response: I wonder what odds she’d need to bet on that? – gavin]

    Comment by JCH — 29 Jan 2012 @ 4:57 PM

  11. Isn’t the real answer to C&W in this remark by physics Nobelist Murray Gell-Mann: “Is it really, really so extremely difficult to persuade people that climate, which is average weather, can have three contributions that add to one another? That is, some cyclical effects, some random noise and a secular steadily rising trend from human activity?”
    H/T Dot Earth

    The point is that – Yes it is really difficult! Even climate scientists can’t understand that. Forget the random noise and just think about the cyclical effect. At some points it is adding to the rising trend but at others it is subtracting. At present the cyclical effect is preventing the rising trend from being obvious.

    Another way to look at this is that natural effects do not have to be adding to global warming. They could be cooling effects, and it is only the increased forcing from the anthropogenic greenhouse effect that has led to the rise in global temperatures. The natural effect could be -30% and the greenhouse effect 130%. The anthropogenic effect does not have to be less than 100%.

    So in my book the IPCC are wrong to quote a 90% probability that the 100% of the global warming is man-made. They should be quoting 100% probability that >100% of global warming is anthropogenic.

    Well that’s my $0.02.

    Cheers, Alastair.

    Comment by Alastair McDonald — 29 Jan 2012 @ 7:01 PM

  12. I see three themes in Judy’s work since her descent into madness:
    1)A desire to find a “compromise” with the denialosphere, which, while noble in spirit, ignores the fact that truth cannot compromise with mendacity.

    2)A strong contrarianism, wherein she will embrace just about any nutty idea so long as it runs against the mainstream.

    3)A craving for the adulation of idiots even if it costs her the respect of colleagues.

    It appears to me that Judy is staking her legacy on the remote possibility that climate science has been flat wrong for 160 years–perhaps with the confidence that if she is right, she’ll be famous, and if wrong no more forgotten than she would have been in any case.

    It’s either that or early onset dementia.

    Comment by Ray Ladbury — 29 Jan 2012 @ 8:30 PM

  13. You find some problems with the BAMS paper here, and the linked Hegerl et al. comment notes specific erroneous statements about AR4. Wouldn’t the review process normally weed out such errors in a short paper, especially when they had also been noted on line?

    Comment by Pete Dunkelberg — 29 Jan 2012 @ 8:57 PM

  14. Ray – The paper I linked on unforced fits Ms Curry well.

    Comment by flxible — 29 Jan 2012 @ 9:35 PM

  15. The key test is whether the person can say “you know, I think I’m right, but it’s possible I may be wrong.”

    At least, I think that’s the key.

    Your keys may differ.

    Comment by Hank Roberts — 29 Jan 2012 @ 9:43 PM

  16. When faced with (partly) unknown risks and risk likelihoods, conservative means to err on the side of caution with regard to those risks. I opine that IPCC AR4 took exactly the opposite tack.

    Comment by David B. Benson — 29 Jan 2012 @ 9:59 PM

  17. flxible @ 14, I don’t see a basis for that. As a professor of science Dr. Curry surely has high cognitive ability. But she has slipped a cog lately.

    Comment by Pete Dunkelberg — 29 Jan 2012 @ 10:48 PM

  18. Comment: I believe this is my first comment on the site. Just wanted to say thanks for the great work. I’ve been reading your posts for the last two years and as a recent graduate student, it’s a real treat to read posts from this blog.

    Question: Why use a Gaussian distribution? I realize it skews the tail of the distribution to the right, but it’s not sticking….

    Thanks!!

    Comment by Alex — 29 Jan 2012 @ 11:44 PM

  19. 11 Alastair McDonald gives himself too little credit-

    He deserves $63.98 atop his two cents worth for raising a sixty four dollar question.

    Comment by Russell — 29 Jan 2012 @ 11:47 PM

  20. Dear Gavin,

    You write,

    “It isn’t an isolated conclusion from a single study, but comes from an assessment of the changing patterns of surface and tropospheric warming, stratospheric cooling, ocean heat content changes, land-ocean contrasts, etc. that collectively demonstrate that there are detectable changes occurring which we can attempt to attribute to one or more physical causes.”

    It is my understanding, based on questions that I asked here previously that you kindly answered, and assuming that I recall and understood your answers correctly, that (i) the changing patterns of surface and tropospheric warming are a signature of warming from any cause and not in fact a unique GHG signature; that (ii) ocean heat content changes are an indication of externally forced warming (e.g. solar or GHG) but not uniquely a GHG signature; that (iii) stratospheric cooling in the lower stratosphere is a signature both of anthropogenic ozone depletion and GHG increases whereas cooling in the mid stratosphere is uniquely a signature of increased GHG concentrations; that (iv) land-ocean contrasts are also a feature of any warming whatever the cause.

    On the subject of stratospheric cooling, the only feature that you say is a unique signature of anthropogenic GHG emissions, I noted subsequently that Prof. Held wrote about stratospheric cooling due to CO2 in passing at his blog (“Ultra fast responses”, 22 Jan 2012):

    “The classic example [see the post for complete understanding of the context] is the cooling of the stratosphere due to increasing CO2. This cooling has no direct connection to the surface/tropospheric warming. If there were a strong negative cloud feedback, say, that prevented the surface/troposphere from warming, the stratospheric cooling would be hardly affected. But this stratospheric cooling does have a substantial effect on N, the energy balance at the top of the atmosphere…”

    Do you agree with Prof. Held? Because it seems to be implied that if the choice is between the theories of Prof. Lindzen and others who maintain the existence of strong negative feedbacks in the tropics, then the existence of stratospheric cooling can not be used to decide which theory is right (i.e. Lindzen or the IPCC).

    [Response: You are conflating the many steps in the argument. OHC increases indicate that changes are related to a net global radiative forcing. Stratospheric cooling rules out other forcings – like solar – from being the dominant cause. Spatial patterns of warming distinguish between aerosol and GHG effects etc. Non-negligible climate sensitivity is mandated by the paleo-climate record. So while any one single issue might be explainable by some other mechanism, there is no individual other mechanism (or combination) that fits everything to the same extent as the GHGs. Thinking otherwise is clutching at straws. – gavin]

    I have also studied the recent paper by Gillett et al. 2011 (Attribution of observed changes in stratospheric ozone and temperature. Atmos. Chem. Phys, 599-609) and this paper concluded that the influence of GHGs on stratospheric temperature can not be detected independently of ozone depleting substances – even in the mid stratosphere. (Have I read the paper correctly?)

    [Response: Haven’t read it, but if they are looking at the SSU data, I don’t know how they good come to that conclusion. I’ll look when I get a chance. – gavin]

    In summary, then, it appears to me that the strongest valid conclusion that we can draw from the lines of empirical evidence that you refer to is that the earth is definitely warming and the warming must be caused by external forcing. It seems to me that in order to draw the stronger conclusion that the IPCC wants to draw, i.e. that,

    “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations”,

    then we really do require the further assumptions (a) the GCM model results are valid; and (b) that absence of evidence of other external forcings than CO2 is evidence of absence of the same.

    Am I correct?

    [Response: No. It doesn’t require GCMs – attribution requires a model of course, but not necessarily a GCM. And there is no assumption that there are no other external forcings. Rather you are positing that despite the currently known forcings explaining the situation well, there must be some factor which negates all of that, and an additional unknown forcing or forcings that has exactly the same net effectt. I (and IPCC) find that scenario very unlikely. – gavin]

    Comment by Alex Harvey — 29 Jan 2012 @ 11:56 PM

  21. > flxible

    Uh, no.

    Comment by Hank Roberts — 30 Jan 2012 @ 12:07 AM

  22. Curry’s problem with the definition of “most” reminds me of Bill Clinton’s “It depends on what the meaning of the word ‘is’ is.”

    The difference is that Clinton’s assertion was valid: “is” has different tenses, resulting in ambiguity in a question. For instance, “Is there a king of France” could be answered either “No” because there is currently no king of France, or “Yes” because, there are lists of numerous kings of France, and each person on that list is a king of France. (In Clinton’s case, the question was about a statement by Monica Lewinsky, “There is no sexual relationship of any kind between me and President Clinton” — this was true at the time she said it. You can put this one right up there with Al Gore saying that he invented the Internet — he never said it, but what he did say was true, as is what he said about Love Story and growing up on a farm … also, he won the debate with GWB by at least 10%, according to all the network polls taken that night, with people disgusted by Bush’s dismissive blather about “fuzzy math”; the notion that Gore lost because of arrogant eye-rolling was a false story promulgated by the media and now accepted as fact. Don’t be a gullible anti-skeptic who swallows political propaganda.)

    Comment by Marcel Kincaid — 30 Jan 2012 @ 1:18 AM

  23. Interestingly in an article yesterday in the UK paper the Mail on Sunday, reported that the UK Met Office and the Climatic Research Unit at the University of East Anglia (headed by Professor Phil Jones) have issued a report based on the data from more than 30000 measuring stations that “confirms that the rising trend in world temperatures ended in 1997″. This is not really consistent with the position taken on this and other sites that global warming is still increasing. Are the Met Office and the CRU mistaken?

    [Response: Given a choice between the Met Office being mistaken and the Daily Mail mangling a story, I’d bet on the latter. There is plenty of short term variability in temperatures, and short term trends are not predictive of longer term ones. Thus claiming that the trend from 1997 or last Tuesday proves that global warming has stopped is simply not justifiable – Indeed, there is plenty of evidence that the long term trends have not changed much at all – see here for instance. I will have an update post on this later this week. – gavin]

    Comment by Ian — 30 Jan 2012 @ 4:30 AM

  24. Gavin says

    With respect to aerosols, the key thing to remember that regardless of the magnitude of the change, the sign of the forcing is almost certainly negative (i.e. the net aerosol effect has been one of cooling). The dominant anthropogenic aerosols are sulphates (derived from the SO2 emitted during the burning of sulphur-containing fossil fuels), which are reflective, and hence cooling. Other aerosols (black carbon, organic carbon, nitrates) are more uncertain, but have a net effect that is smaller.

    The issue though is not whether the net effect of aerosols is to cool or heat. The real issue is the direction in which this effect been heading. It is for instance arguable that with the clean up of dirty power plants in most of the developed world the negative impact was reduced. Of course more recently China and India may have reversed this trend.

    Comment by Sceptical Wombat — 30 Jan 2012 @ 6:09 AM

  25. The IPCCs method of formulating probabilistic statements seems pretty clear and unambiguous to me. In fact they are very similar to the PAC (probably approximately correct) bounds that are used in computational learning theory (a rather mathematical branch of statistics concerned with how much can be learned from data). If there were a problem with the ambiguity of such statement of that form, then the COLT crowd wouldn’t be interested in them.

    It is ironic that someone with such a weak grasp of probabilistic reasoning should be writing papers on the subject, it is a recipe for the Dunning-Kruger effect.

    Comment by Dikran Marsupial — 30 Jan 2012 @ 7:19 AM

  26. [[I think it’s an effort to change the content of AR5 … not just Curry et al but calls for change in process, etc.]]

    I might be fun to make up a story where IPCC gives US officials a politically tailor-made version of the AR5, but I doubt I ever write it.

    Comment by Oale — 30 Jan 2012 @ 7:31 AM

  27. > A strong contrarianism, wherein she will embrace just about any nutty idea so long as it runs against the mainstream.

    I’ve run across the term “Climate Hipster” for someone that just rejects the mainstream for its own sake.

    Comment by Dave H — 30 Jan 2012 @ 7:46 AM

  28. There are some cross-purposes at work here.

    Curry is indulging in some theoretical quasi-philosophical musings. Maybe-this-and-maybe-that kind of stuff.

    People interested in the specific scientific questions – what’s the evidence for x – naturally find her assertions infuriatingly vague, and ask for some kind of evidentiary substantiation. And they are almost always disappointed.

    Comment by Michael — 30 Jan 2012 @ 8:30 AM

  29. Alex Harvey,
    You know, when you have to twist logic to that extent to justify your point of view, I’ve found it’s a pretty good indication that your point of veiw is just flat wrong. Anthropogenic GHGs can explain both the stratospheric cooling and tropospheric warming–in fact they were the basis for predicting these effects well in advance of their observation.

    In science we usually subject hypotheses to rather more stringent criteria than the straight-face test.

    Comment by Ray Ladbury — 30 Jan 2012 @ 9:53 AM

  30. Re: #22 … Thank you. I’ve become as wearied by the persistent invocations of the Clintonian “is” parsing as I have by the Gore/internet fable. Read the transcript of the interrogation and it’s plain his response was to request a legitimate clarification of what was being asked. OT, I know (although the carelessness exhibited in flaunting the “is” moment is not unlike that of the climate change deniers waving random data).

    Comment by couldabin — 30 Jan 2012 @ 10:27 AM

  31. How can a greenhouse gas cause warming in one layer of the atmosphere but cooling in another? I’ve read the assertions by Dr. Uherek but don’t see compelling logic to support the claim. If CO2 “traps” heat (in the troposphere), then it will trap heat everywhere.

    [Response: This is the danger of taking analogies too far. What CO2 does is absorb energy at specific frequencies depending on how much of that energy is around, and emit energy at those same frequencies as a function of the local temperature. In the troposphere, there is plenty of upwelling IR in the right range, and so CO2 does a lot of absorption and the radiation to the surface from the GHGs warms the surface more than it would have been. In the stratosphere, there is less radiation in those specific bands, and so increases in CO2 increase the emission more than the absorption, thus cooling those layers. – gavin]

    Comment by Veritas — 30 Jan 2012 @ 10:58 AM

  32. Gavin, inline #23 (and thus also a response to Ian), here’s what the Met Office REALLY said:
    http://metofficenews.wordpress.com/2012/01/29/met-office-in-the-media-29-january-2012/

    Comment by Marco — 30 Jan 2012 @ 11:53 AM

  33. Hi Gavin,

    could you correct your graph showing the GISS temp anomalies for the 20th century, where one of the colors in the legend is missing (associated with CMIP5 simulations).

    Thx,
    Richard

    [Response: All the lines are CMIP5 simulations (i.e. that was a title, not a line on it’s own). – gavin]

    Comment by Richard Harvey — 30 Jan 2012 @ 12:01 PM

  34. Gavin wrote:

    “attribution requires a model of course, but not necessarily a GCM”

    Permit me a slight tweak. Attribution, writ large, requires a logic structure (engineers call these “fault trees”), but not a model, per se. In this case, the model is used to bridge the gap between the the physics of GHGs, and predictions about future climate. In the vast majority of fields of inquiry, the gap between theory and prediction is bridged with empirical results via input/output testing. Ideally, the empirical results eliminate all possible root causes until only one survives. This is still a “very likely” attribution, since input/output testing results can be misinterpreted. Unfortunately, climate science does not have the luxury of input/output testing of the climate, and so relies almost exclusively on models to yield predictions. With attribution assessed with model output rather than empirical test output, there is simply no way to assess probability in any meaningful way.

    [Response: Your distinction between ‘input/output’ testing and ‘models’ is lost on me. A GCM is a model, but so is the equation y = mx+b used to fit data to a straight line. So is any sort of input / output testing that engineers use. Indeed, all of science and engineers depends on models to relate theory with empirical observations. There is nothing distinct or different about climate. The challenge of course is that the timescales are very long, so we cannot test all predictions in real time. The same is true of much of engineering of course. Although it would be ideal, when building a bridge, to drive heavier and heavier trucks over it until it collapses, and then rebuild the bridge with a sign saying what the load limit is, bridge engineers don’t do that. They use prior observations and yes, models, to calculate probabilities. And yes, those probabilities are meaningful.–eric]

    Comment by Matt Skaggs — 30 Jan 2012 @ 12:36 PM

  35. http://www.dailymail.co.uk/sciencetech/article-2093264/Forget-global-warming–Cycle-25-need-worry-NASA-scientists-right-Thames-freezing-again.html is what Ian mentioned above.

    Comment by Hank Roberts — 30 Jan 2012 @ 12:48 PM

  36. @20
    “Gillett et al. 2011″

    The attribution of stratospheric temperature changes to CO2 and ODS changes is quite different from traditional approach, i.e. attribution to CO2 and prescribed ozone changes. The latter is simpler, but it neglects the ozone-temperature feedback; Gillet et al. tried the former, but they were not (yet) able to untangle the influences of CO2 and ODS.

    Comment by doskonaleszare — 30 Jan 2012 @ 1:02 PM

  37. Ian@23 The Met Office has responded to the Daily Mai’s misrepresentation

    “Today the Mail on Sunday published a story written by David Rose entitled “Forget global warming – it’s Cycle 25 we need to worry about”.

    This article includes numerous errors in the reporting of published peer reviewed science undertaken by the Met Office Hadley Centre and for Mr. Rose to suggest that the latest global temperatures available show no warming in the last 15 years is entirely misleading.”

    http://metofficenews.wordpress.com/2012/01/29/met-office-in-the-media-29-january-2012/?tw_p=twt

    Comment by Louise — 30 Jan 2012 @ 1:09 PM

  38. Sorry for the digression.

    The “Cycle 25″ stuff I think originates with David Archibald at WTF, ending with a chart displaying a linear extrapolation predicting Cycle 25 will have almost no sunspots. The hype omits mention of Archibald and WTF and attributes it to “NASA” — devious, aren’t they?

    The linear extrapolation is based on work by Livingston and Penn, I think this: http://www.noao.edu/staff/mpenn/PennLivingston_preprint.pdf

    In that, Livingston and Penn write:

    “It is important to note that it is always risky to extrapolate linear trends; but the importance of the implications from making such an assumption justify its mention. …. if a large number of sunspots with magnetic field strengths greater than 3000 Gauss do appear, then the extrapolated PDF will be shown to be erroneous. We will see in the coming months and years.”

    Comment by Hank Roberts — 30 Jan 2012 @ 2:11 PM

  39. aside — has anyone used the CMIP data to chart what temperatures would have been -without- the increased use of fossil fuels (removing both the greenhouse warming and the sulfate cooling effects)? It’s worth remembering that natural variation (with or without a sunspot extended minimum) is significant.

    [Response: Yes. The CMIP protocol includes “historicalNat” runs which are only using volcanoes and solar as 20th C forcings. I’ll make a figure when I get a chance. – gavin]

    Comment by Hank Roberts — 30 Jan 2012 @ 2:23 PM

  40. “In reality, Gavin’s conclusion on the role of the anthropogenic emissions of greenhouse gases as dominating changes in climate statistics is close to being refuted.”

    says Pielke Sr. Climate stats!

    [Response: What a strange comment. It mixes up projections with hindcasts, conflates the IPCC statement with a strawman that no other factors have any effect, and finishes up with an apparent claim that because there is month to month variability in the MSU data, the long term trends are not attributable. Plus the confusion about the dominant factors in MSU4 (hint, it isn’t CO2). – gavin]

    Comment by grypo — 30 Jan 2012 @ 2:44 PM

  41. I was struck by the margin of caution between the AR4 attribution statement, p(x<50%) < 10%, and what you got from the simplified attribution exercise above, p(x<50%) < 1%. Would this reflect the actual margin between that statement and the confidence levels in the formal attribution studies it sums up, too?

    I sometimes find myself having to explain that “expert judgment” in this context does not mean simply a poll of scientists’ subjective views, but comes out of doing the math. Would it also be appropriate to describe the expert judgment as ten times more “conservative” than the calculations on which it is based?

    Comment by CM — 30 Jan 2012 @ 2:52 PM

  42. At what level of certainty are the terms “could”, “might” and “should” become “can”, “shall” and “does”? If AGW scenarios are so certain, why are they not predictions?

    [Response: Because there are a huge number of paths that society might take into the future which will affect emissions. Thus all of the specific model simulations, which rely on scenarios of socio-economic-technological change, can’t possibly be definitive. What can be definitive are statements like, all else being equal, increasing GHGs will lead to significant temperature changes and consequent changes in many aspects of the climate. But note that certainty of a statement is inversely proportional to the detail contained within it. – gavin]

    If AGW is not a theory, not up to the level of hypothesis, then uncertainty makes the demonstrative or imperative into the conditional or even subjective. Are we not there yet, with “very likely” and “95%”? What would it take to remove the conditionals? I understand that science always has error bars, but if the error bars are actually small, the “science” is really now “applied engineering”.

    If AGW is both settled and certain, I expect, as for Einstein’s “scenarios” of relativity, that there are hard statements to be made about other events and the future that can be checked for accuracy. If the reason is that climate science is young and the subject, complex, then the certainty is not high. “Very likely” is “Possible”, not even “Probable”. We expect little from something possible, though, like drinking contaminated water in the Rocky Mountains, the possibility is sufficiently alarming to make us stick to bottled fluids.

    There appears to me to be a disconnect between the actual certainty of process and outcome and the ability to make predictive statements based on the certainty proposed. This is not to say that we should not act on the potential outcome, but that we should be realistic about the actual threat. If settled and certain they are, then let’s test them. If, after 24 years, we still can’t make predictive statements of the next decade, that neither the nominal nor the catastrophic case can be ruled out, we should know.

    IPCC AGW scenarios are Noahian deluge, Ark-worthy, with the “very likely” and “95%” certainty subtext. But unlike God’s sudden storms, we are facing an incremental, progressive threat (even if, with time, things get worse). Let’s see what and when things will happen.

    You can’t reasonably have it both ways: both settled/certain and impossible to predict.

    Comment by Doug Proctor — 30 Jan 2012 @ 4:24 PM

  43. That post by Pielke senior is just idiotic to the point of being offensive.

    Nice smack down of Curry and Webster by Hegerl et al. What a waste of their time having to refute such bad science.

    I am still in disbelief that BAMS published Curry and Webster’s paper; also after reading Hegerl et al.’s response I do not know how Curry and Webster made it through peer review. So much for gate keeping.

    Comment by MapleLeaf — 30 Jan 2012 @ 5:12 PM

  44. @23 Ian

    You might want to check out what the UK Met Office has to say about the “reporting” being done by the The Daily Mail

    http://metofficenews.wordpress.com/

    Met Office in the Media: 29 January 2012

    Comment by George Ennis — 30 Jan 2012 @ 6:32 PM

  45. #38 Hank Roberts

    Gee, and I was so hoping the quiet sun theory would actually work out :)

    http://ossfoundation.us/the-leading-edge/projects/environment/global-warming/current-climate-conditions/solar#section-10

    a 0.1 W/m2 relief would have been nice…

    I do think it’s funny that people are still hyping quiet sun though, I’ve seen it a few times this year.

    Comment by John P. Reisman (OSS Foundation) — 30 Jan 2012 @ 7:01 PM

  46. I haven’t read the C&W paper, but I did look at her Santa Fe power point slides. :) Curry has stopped being a scientist long ago. A scientist concerned about the uncertainties would try to quantify them. A propagandist would simply raise them.

    Comment by gator — 30 Jan 2012 @ 7:04 PM

  47. Gavin,

    Thank you.

    I made much the same statement as to what the IPCC AR4 PR actually meant on Dr. C’s blog;

    http://judithcurry.com/2012/01/13/week-in-review-11312/#comment-158653
    http://judithcurry.com/2012/01/13/week-in-review-11312/#comment-158870

    This was in the context of Dr. C’s agreement with Dr. Muller’s incorrect understanding of what the IPCC actually said in the original IPCC PR statement (in fact, at that time I called Dr. Muller a liar, strong words yes, but at that time, I had had just about enough of the “I Don’t Know” five blog posts per week nonsense that Dr. C loves to cultivate).

    No correction was ever offered for their incorrect statements (Dr. C’s and Dr. Muller’s).

    But The Three Stooges (note that there were actually more than 3 Stooges) did make their presence known at that time. Quite humorous, in a “bite me” sort of way.

    Best Regards.

    Comment by EFS_Junior — 30 Jan 2012 @ 7:33 PM

  48. > I was so hoping the quiet sun theory would actually work out

    I still am hoping.

    I’m also hoping we’d be smart about getting a grace period, if it happens.

    [Response:This never reached the quality of ‘hypothesis’, let alone ‘theory’. It was vain hope and conjecture, nothing more. Predicting solar activity on this kind of timescale, while ignoring the eminently more predictable (and larger magnitude) future forcing of CO2, is just plain silly. Hank: I know you know this. Don’t encourage people’s misconceptions! –eric]

    Comment by Hank Roberts — 30 Jan 2012 @ 8:52 PM

  49. Doug Proctor #42

    You can’t reasonably have it both ways: both settled/certain and impossible to predict.

    Actually you can: a trivial but very familiar example is weather prediction, which is based upon very settled science yet doesn’t work (well) more than a few days ahead.

    An example unrelated to chaotic behaviour would be from my own experience, in a previous life, where I was expected to predict the location where a Soviet satellite containing a nuclear power plant was supposed to come down.

    Such a satellite orbits the Earth in 1.5 hours, while the Earth rotates underneath once every 24 hours. A fair metaphor for a rou lette wheel… and it is indeed impossible even to tell which ocean or continent the thing will come down over, until the very last orbit!

    Yet, would you say that celestial mechanics is not ‘settled science’?

    But, yes, it is possible to make certain predictions also in climatology. Not very useful, but solidly certain allright. Like: temperatures will not fall back to pre-1970s level over the coming decade. Or over the following one. Or the following. Or at any forseeable time — unless we learn to stop emitting, and start actively pulling CO2 down from the atmosphere.

    Comment by Martin Vermeer — 31 Jan 2012 @ 1:56 AM

  50. Gavin Schmidt the RC team – thank you for the clear explanation of why C&W 2011 and Dr Curry’s personal statements on the matter of IPCC statements on attribution are in error, and particular thanks for making it clear and sufficiently plainly-worded that a layman can understand it. Conversely (and I admit it may just be my own limitation) I find Dr Curry’s copious blog posts on this issue impenetrable, despite responses to calls for clarification. As it turns out, the word “most” is not nebulously woolly but means…err, well not half and not less than half, much as I always thought it did, and “very likely” does mean “look I wouldn’t call it a dead cert but I’d be gobsmacked if it didn’t turn out that way”. Certainly it seems to me certain people are certainly uncertain about “uncertainty”.

    Comment by SteveC — 31 Jan 2012 @ 2:39 AM

  51. #49–

    Not very useful, but solidly certain allright. Like: temperatures will not fall back to pre-1970s level over the coming decade. Or over the following one. Or the following. Or at any forseeable time — unless we learn to stop emitting, and start actively pulling CO2 down from the atmosphere.

    Well, that’s potentially a very useful prediction indeed. :-(

    Comment by Kevin McKinney — 31 Jan 2012 @ 6:24 AM

  52. Doug Proctor,
    Perhaps part of you confusion arises from misunderstanding where the idea of anthropogenic global warming comes from. It is not, in and of itself, a theory. It is, rather, a prediction of the consensus theory of Earth’s climate. In this theory, increasing greenhouse gasses cause warming–independent of how that increase occurs. The prediction that anthropogenic greenhouse gasses from fossil fuel burning would warm the climate dates from Svante Arrhenius in 1896.

    The consensus model of Earth’s climate actually has a long list of impressive successes:

    http://bartonpaullevenson.com/ModelsReliable.html

    There are certainly uncertainties in the model, but they do not invalidate the basic structure of the model–which performs well for the most part–and they certainly do not invalidate what we think we know with high confidence about the planet’s climate. Certainly, the so-called skeptics present no positive alternative interpretations that have exhibited any predictive power whatsoever.

    So, my quesiton would be this: Given that we have a model that has demonstrated significant predictive power(17 successful predictions), that no serious and irremediable problems have been found and no unambiguous predictive failures seen, and given that it exhibits behavior that looks like what we see on planet Earth and that there are no alternative models with anywhere near the success of the current consensus model, why the hell wouldn’t we rely on it to give us guidance precisely where it is most reliable (e.g. the response of the climate to changes in greenhouse gasses)?

    Comment by Ray Ladbury — 31 Jan 2012 @ 10:40 AM

  53. Curry believes it is possible there could be global cooling over the next decades – say 20 to 30 years.

    [Response: I wonder what odds she’d need to bet on that? – gavin]

    No odds, of course.

    We don’t know what the climate will be for the next several decades, there are a number of reasons to expect the continue flat trend for the next several decades. In terms of when global warming will come “roaring back”, it is possible that this may not happen for the first half of the 21st century.

    I am being asked what is meant by “possible”. More than 50%? Well the whole situation is too uncertain to put probabilities on, IMO. Hence my previous suggestions for looking at a “possibility distribution” rather than trying to guess at probabilities. And for generating scenarios via scenario falsification.


    post

    The emissions scenario is already factored into the different predictions. So it down to solar forcing (which she says may be low for 90 years) having a large impact, volcanoes, and oscillations. She doesn’t mention that the further we get out, the possibility of cooling factors becomes vanishingly small, nor is there any mention of what happens if these factors all don’t work out well.

    Comment by grypo — 31 Jan 2012 @ 10:58 AM

  54. Doug Proctor wrote: “If AGW is not a theory, not up to the level of hypothesis …”

    Anthropogenic global warming is neither a “theory” nor a “hypothesis”.

    It is an empirically observed fact.

    Comment by SecularAnimist — 31 Jan 2012 @ 11:16 AM

  55. > It is an empirically observed fact.

    It is also a specific prediction by a theory that has very broad application, like explaining why the Earth surface has the temperatures it has (making the Earth inhabitable), why mountains often have snow tops (Tyndall was a mountaineer!) — but also such esoteric astronomy gems like why the Solar spectrum (and stellar spectra) and the brightness of the Solar disc look the way they do, etc.

    Comment by Martin Vermeer — 31 Jan 2012 @ 12:06 PM

  56. > … global warming will come “roaring back”, …
    > this may not happen for the first half of the 21st century.

    “I believe it is peace for our time… Go home and get a nice quiet sleep.”

    http://eudocs.lib.byu.edu/index.php/Neville_Chamberlain%27s_%22Peace_For_Our_Time%22_speech

    Comment by Hank Roberts — 31 Jan 2012 @ 12:31 PM

  57. [edit – please stay substantive]

    Comment by Ray Ladbury — 31 Jan 2012 @ 1:06 PM

  58. why mountains often have snow tops (Tyndall was a mountaineer!)

    OT but this is a great tidbit, something I was unaware of (Tyndall being a mountaineer).

    [Response: This is true. However, it is also true that Tyndall was specifically looking for a way to understand the apparent history of earth’s temperature changes, due to geologic evidence about ice ages, which at the time went against everything physicists thought they knew about the sun. He says so in his original paper. Geology begets physics, in other words! –eric]

    Comment by dhogaza — 31 Jan 2012 @ 1:16 PM

  59. Also a railroad surveyor. . . more here, if you’re interested:

    http://doc-snow.hubpages.com/hub/Global-Warming-Science-In-The-Age-Of-Queen-Victoria

    Comment by Kevin McKinney — 31 Jan 2012 @ 1:47 PM

  60. > ignoring the eminently more predictable (and larger magnitude)
    > future forcing of CO2, is just plain silly.

    I agree completely, Eric.

    What I mean is that even if we got a magical grace period from the sun’s variability, it seems we’d fail to take advantage of the opportunity any such little delay gives us.

    Take a different case — China and India experiencing 1800s British coal smoke smogs, 1960s US acid rain, and contemporary mercury pollution by burning coal with no air pollution controls.

    That’s increasing the world’s longterm problems from more CO2 in the air and oceans.

    It’s also given some brief minor reduction in warming due to sulfates.

    Or say we had another mega-volcano causing a few cold years.

    Would we be smart enough to use any opportunity to move away from carbon fuels?

    Doesn’t seem like we’re that smart.

    “Delay is the deadliest form of denial.”

    Comment by Hank Roberts — 31 Jan 2012 @ 2:22 PM

  61. # 53 grypo

    I’ve said this before, and it is very simple to understand.

    – An extended solar minimum would remove on avert around 0.1 W/m2
    – Relative thermal equilibrium for the Holocene is 0.0 (zero)
    – Current estimates of positive forcing are around 1.8 W/m2
    – Subtract 1.8 W/m2 – 0.1 W/m2 = 1.7 W/m2

    In other words, it certainly looks like we will continue warming even with a quiet sun, based on the known evidence.

    This understanding of course does not account for the unknown factors. There may be an alien race in a cloaked spacecraft that will soon aim their cooling ray guns at our oceans to save us.

    Personally I’m a bit skeptical about the possibility of aliens trying to help us out though.

    Comment by John P. Reisman (OSS Foundation) — 31 Jan 2012 @ 3:23 PM

  62. Rather you are positing that despite the currently known forcings explaining the situation well, there must be some factor which negates all of that, and an additional unknown forcing or forcings that has exactly the same net effectt.

    This was pointed out to Alex repeatedly at Deltoid. The problem seems to be the employment of two different epistemologies, one in which propositions are given provisional probabilistic truth status based on the degree to which they are supported by evidence, and the other in which all propositions that have not been formally proven are given equal epistemological status. The first is the epistemology of science and all rational empirical inquiry; human beings could not function without it in their daily lives, let alone science. The second is a misapplication of deductive standards of proof from logic and mathematics to empirical matters.

    Comment by Marcel Kincaid — 31 Jan 2012 @ 3:23 PM

  63. Let’s see what and when things will happen.

    One could say the same, with equal wisdom, about cigarette smoking, laying out in the sun until your skin peels, or eating three hamburgers a day and never getting off the couch.

    You can’t reasonably have it both ways: both settled/certain and impossible to predict.

    This is well known from Chaos Theory to be wrong: determinism does not imply predictability.

    Comment by Marcel Kincaid — 31 Jan 2012 @ 3:33 PM

  64. In terms of when global warming will come “roaring back”, it is possible that this may not happen for the first half of the 21st century.

    I am being asked what is meant by “possible”. More than 50%? Well the whole situation is too uncertain to put probabilities on, IMO. Hence my previous suggestions for looking at a “possibility distribution” rather than trying to guess at probabilities.

    Is English not Professor Curry’s native language? She seems to have no idea what these words mean.

    Comment by Marcel Kincaid — 31 Jan 2012 @ 3:41 PM

  65. re Marcel Kincaid (22)
    OT but very insightful. I am neither a fan of Clinton nor Gore but it is instructive how fabled lore leaves truth in the dust, like your recounting of Clinton’s testimony. The lore has become a great sound bite and metaphor but entirely misconstrued. I’m sure there’s some connection with the AGW debate but none comes to mind at the moment. Same can be said of Gore’s invention of the internet tale.

    Comment by Rod B — 31 Jan 2012 @ 3:54 PM

  66. Hank, true, delay is the deadliest form of denial. It is also, in general, the greatest protection against rash behavior.

    Comment by Rod B — 31 Jan 2012 @ 4:07 PM

  67. The OP starts “Back in 2007, the IPCC AR4 SPM stated that:

    “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.”

    This is a clear statement that I think is very well supported”

    I think the statement is misleading and incorrect. It takes the net effects of GHGs, solar, aerosols, natural variability, etc and asserts that one cause, GHGs, very likely caused >50% but less than 100% of the net result. Why less than 100%? Because “most of” by common usage means “less than all”. However, if we expand the previously posted efforts which backed out ENSO, solar, and volcanoes, to also include aerosols, and perhaps also figure in the thermal inertia of the system and all other factors, I’m sure that the best estimate is that anthropogengic GHGs have caused greater than all of the observed increase in global average temperature.

    Would the moderators be kind enough to make their best guess as to a REAL percentage? I’m guessing that if they do they’d instead say something like, “It is probable that anthropogenic GHGs have caused 150% +-20% of the observed global temperature increase, some of which has been masked by aerosols, thermal inertia, and/or natural variability. It is almost certain that at least 100% of the observed increase is due to anthropgenic GHGs.”

    The 150%, 20%, and 100% numbers are made up, and the inclusion of thermal inertia is questionable, but you get the drift.

    Comment by RichardC — 31 Jan 2012 @ 4:39 PM

  68. Well, forgive me while I go badly off topic but there’s an interesting story here regarding Tyndall and mountaineering. Tyndall was indeed a mountaineer and a pretty good one. He made two of the early attempts on the Matterhorn before the infamous first ascent (with fatalities) by Edward Whymper et al. His second attempt reached the west ridge, a couple hundred meters below the summit, the highest point reached at that time, and later named for him as Pik Tyndall.

    Mt Tyndall in California’s Sierra Nevada is also named for him, the summit of which is just a few meters higher than the point he reached on the Matterhorn. This peak in turn has its own interesting history, being first climbed by Clarence King then of the California Geological Survey (and later the first director of the USGS), from which he identified and named Mt. Whitney, the highest peak in the continental U.S. However, when he attempted Whitney’s first ascent several years later (1871), he mistakenly climbed what is now Mt. Langley instead. Langley, as it turns out, was named (later) for Samuel Langley, who actually did climb Mt Whitney (in 1881), making the temperature and infrared radiation measurements subsequently used by Arrhenius in his first calculations of the greenhouse effect.

    Comment by Jim — 31 Jan 2012 @ 4:41 PM

  69. #68–OT, of course, but Tyndall’s “signature” climb was the first solo ascent of Monte Rosa, August 17, 1858. It was an impromptu affair:

    “After breakfast I poured what remained of my tea into a small glass bottle, an ordinary demi-bouteille in fact; the waiter then provided me with a ham sandwich, and, with my scrip thus frugally furnished, I thought the heights of Monte Rosa might be won…”

    http://en.wikipedia.org/wiki/Monte_Rosa#First_ascents

    [Response:I think Tyndall would probably beg to differ. The Matterhorn is the much more difficult climb–which is why its first ascent was a full 10 years after Monte Rosa.–Jim]

    Comment by Kevin McKinney — 31 Jan 2012 @ 5:16 PM

  70. > the greatest protection against rash behavior

    That would be science.

    Regrettably there wasn’t enough of that available when we got into this handbasket and started down our current path.

    The delay changing our behavior, with what we know now, is — say, doesn’t this language have a word for short term profit by intergenerational theft? Hmmmm, there ought to be a word for that.

    Comment by Hank Roberts — 31 Jan 2012 @ 7:03 PM

  71. http://news.sciencemag.org/sciencenow/2012/01/volcanoes-indicted-for-europes-l.html

    Comment by Hank Roberts — 31 Jan 2012 @ 7:21 PM

  72. Rod B. says, “delay is… also, in general, the greatest protection against rash behavior.”

    You know, there was a guy on I-66 the other day that had that motto. They scraped what was left of him off of a semi’s back bumper.

    Comment by Ray Ladbury — 31 Jan 2012 @ 8:34 PM

  73. Re the Sciencemag link, based on a few model runs out of who knows how many.

    Sounds like describing only one or strands of the spaghetti chart.

    Here, let me fiddle with that Sciencenow language a bit. I’m
    speculating that what they meant to write was something like:

    Out of _____ model runs,

    … sea ice

    in at least some model runs
    southward along the east coast of Greenland….

    in at least some model runs,
    melting made surface waters less salty,

    in at least some model runs,
    reducing ocean mixing and

    in at least some model runs,
    chilling the waters that return to the Arctic.

    the colder water

    in at least some model runs,
    completed a feedback loop by

    in at least some model runs,
    encouraging the formation of more sea ice

    that

    in at least some model runs,
    maintained an icy chill

    in at least some model runs,
    directly upwind of Europe

    for
    in at least some model runs,
    centuries.

    Comment by Hank Roberts — 31 Jan 2012 @ 8:47 PM

  74. “[Response:I think Tyndall would probably beg to differ. The Matterhorn is the much more difficult climb–which is why its first ascent was a full 10 years after Monte Rosa.–Jim]”

    Certainly–Tyndall himself didn’t make much of the climb, as I think the quote I gave suggests.

    Nevertheless, it still seems to me that the Monte Rosa climb is (so to speak) ‘most cited.’

    Comment by Kevin McKinney — 31 Jan 2012 @ 9:07 PM

  75. 54 SA says, “Anthropogenic global warming is neither a “theory” nor a “hypothesis”.

    It is an empirically observed fact.”

    I agree that warming of the lower troposphere is an empirically observed fact, but I think you step out of bounds by including attribution.

    Comment by RichardC — 31 Jan 2012 @ 10:29 PM

  76. For Richard C: http://www.realclimate.org/images/temp_20C-1024×787.jpg

    Comment by Hank Roberts — 1 Feb 2012 @ 1:07 AM

  77. #75 RichardC

    Ever heard of cause and effect?

    Comment by John P. Reisman (OSS Foundation) — 1 Feb 2012 @ 1:27 AM

  78. This iconic attribution statement seems to understate the human contribution, esp because it doesn’t specify the range or most likely value, but only (an underestimate of) the lower limit.

    Besides specifying a range, it would have been useful to also focus on the net anthropogenic contribution rather than solely on the greenhouse gas contribution.

    Comment by Bart Verheggen — 1 Feb 2012 @ 3:18 AM

  79. I agree that warming of the lower troposphere is an empirically observed fact, but I think you step out of bounds by including attribution.

    Richard I think it is you who is stepping out of bounds. Note that any observation process is also a modelling process: a thermometer only gives proper temperatures if it is properly calibrated, i.e., you apply a calibration model to the raw values. This is a trivial example: the model behind the use of the satellite MSU data is pretty complex. Processing surface station data into a global average is somewhere in-between. Yet, we call all these “empirical observations”.

    Also the fact that it is mostly CO2 etc. that is behind the current warming is an empirical observation, in the same sense. We know based on physical theory what increasing CO2 concentrations should do, and what we now see happen was predicted well before it started happening. You can point a $50 radiometer at the sky and see the back radiation for yourself — and more of it the more CO2 (and H2O) molecules there are along your line of sight, going down to the horizon. Satellites have done that too looking down, and yes, the thermal infrared spectrum has changed in pretty much the way expected.

    http://www.skepticalscience.com/empirical-evidence-for-co2-enhanced-greenhouse-effect.htm

    If you want to disbelieve this, not only do you have to provide an alternate cause for the warming (perhaps not evidently absurd to a non-expert), you also have to explain why observed changes in the outgoing IR spectrum do not do what common sense tells they are doing.

    It doesn’t get any closer to ‘empirical observation’ than that.

    Comment by Martin Vermeer — 1 Feb 2012 @ 4:30 AM

  80. From Prof. Curry’s paper “The third type [of uncertainty detectective] is the merchant of doubt (Oreskes and Collins, 2010), who distorts and magnifies uncertainties as an excuse for inaction for financial or ideological reasons”.

    Prof. Curry is a merchant of meta-doubt! Rather than simply magnify the scientific uncertainties, she attempts to undermine the ability of science to quantify the certainty using probabilistic terms.

    Comment by Dikran Marsupial — 1 Feb 2012 @ 5:17 AM

  81. Does anyone know where the GISS temperatures database
    http://data.giss.nasa.gov/work/gistemp/STATIONS//tmp. (station.number)/station.txt
    has moved to?

    Comment by vukcevic — 1 Feb 2012 @ 8:00 AM

  82. “I agree that warming of the lower troposphere is an empirically observed fact, but I think you step out of bounds by including attribution.”

    If you do audits, not if you do science.

    I like Michael Tobis’s (IIRC) take on AGW – the consequence of existing laws and theories.

    Comment by J Bowers — 1 Feb 2012 @ 8:59 AM

  83. Dear Gavin, #20:

    Thank you for your responses, but I remain interested in the stratospheric cooling.

    The Executive Summary of the AR4 WG1 report states,

    “Further evidence has accumulated of an anthropogenic influence on the temperature of the free atmosphere as measured by radiosondes and satellite-based instruments. The observed pattern of tropospheric warming and stratospheric cooling is _very likely_ due to the influence of anthropogenic forcing, particularly greenhouse gases and stratospheric ozone depletion.”

    Prof. Held seems to be saying that the existence of stratospheric cooling tells us nothing about the sensitivity of the climate to increasing greenhouse gases. If there were strong negative feedbacks that prevented the surface from warming, the stratosphere would cool just the same. If so, I fail to see why stratospheric cooling is even mentioned in the context of attributing global warming.

    I understand that all of the strands of evidence need to be looked at as a whole but at the same time it appears that three of the strands – stratospheric cooling, tropospheric warming, and the land-ocean constrasts – are not actually able to distinguish between hypothetical causes. These features all would occur whatever the cause of the observed warming at the surface and in the oceans. Or am I confused?

    By the way, I wonder if there have been modelling experiments using low sensitivity GCMs forced with increased solar radiation as well as with measured changes in CO2 and ozone depleting substances. In order for the stratospheric cooling to be relevant, I would want to know how the pattern of stratospheric cooling compares in this thought experiment would compare with the observed pattern. Would it differ in any way at all?

    Comment by Alex Harvey — 1 Feb 2012 @ 9:09 AM

  84. Richard C., Really? What would it take for you to be convinced that CO2 was behind the majority of the warming? I mean we already know that CO2 is a greenhouse gas and that increasing greenhouse gasses lead to increased warming. We already know that other putative causes–e.g. heat from the oceans or increased insolation–won’t cut it. We know the stratosphere is cooling even as the troposphere warms. We know the warming matches quite well what is expected from greenhouse gasses. We know we’ve increased CO2 by ~40% over preindustrial times. This is just a beginning.

    I give up, dude. What’s missing.

    Comment by Ray Ladbury — 1 Feb 2012 @ 9:18 AM

  85. RichardC wrote: “I agree that warming of the lower troposphere is an empirically observed fact, but I think you step out of bounds by including attribution.”

    This is like saying that we observe that apples fall from trees, and we know that gravity exists and causes unsupported objects to fall, but we “step out of bounds” if we attribute the fall of an apple to gravity.

    After all, that particular apple might be falling because of sunspots.

    Comment by SecularAnimist — 1 Feb 2012 @ 10:49 AM

  86. #83–

    . . .stratospheric cooling, tropospheric warming, and the land-ocean constrasts – are not actually able to distinguish between hypothetical causes. These features all would occur whatever the cause of the observed warming at the surface and in the oceans. Or am I confused?

    Yes, Alex, you are confused. As Gavin told you previously, stratospheric cooling is diagnostic of the greenhouse effect ‘in action’–although it is true that lower stratospheric cooling also partially reflects ozone depletion.

    That means that, although it may in principle be possible for mysterious ‘negative feedbacks’ (which would be incompatible with the paleo-climate record) to mask surface warming while leaving the stratospheric cooling untouched, the stratospheric cooling actually observed is evidence that the greenhouse effect is now active–since there is no other cause for the total observed stratospheric cooling.

    And if we know that the greenhouse effect is acting to cool the stratosphere, then it is a more-than-reasonable inference that it also accounts for (some percentage of) the observed warming at various levels of the troposphere, including the surface.

    Hope that helps pull together some of the ‘strands of evidence’ for you.

    Comment by Kevin McKinney — 1 Feb 2012 @ 11:49 AM

  87. MS 34: Unfortunately, climate science does not have the luxury of input/output testing of the climate

    BPL: Sure it does.

    http://bartonpaullevenson.com/ModelsReliable.html

    Here goes another heroic attempt to get past RealClimate’s ReCaptcha…

    Comment by Barton Paul Levenson — 1 Feb 2012 @ 11:59 AM

  88. BPL,
    I am not sure that you understand input/output testing.

    Comment by Dan H. — 1 Feb 2012 @ 12:50 PM

  89. Ray (72), true, while delay is in general the greatest protection against rash behavior it can also cause some grief!

    Comment by Rod B — 1 Feb 2012 @ 1:42 PM

  90. There’s no particular virtue in delay. A sensible person takes the action that his intelligence says is required. Doctors perform emergency surgeries when a delay would mean death.

    Given the information we have, we don’t have the time to burn all the coal and oil in the ground first. Which is the object of the delay. Not to spare us from some rash, foolish act.

    Comment by Jeffrey Davis — 1 Feb 2012 @ 3:50 PM

  91. Rod B (89): Let’s turn your premise on its head. When engaged in rash behavior (i.e. performing a global atmospheric experiment that gives every sign of going horribly awry), delaying the cessation of that behavior nothing but rash itself.

    Comment by MartinJB — 1 Feb 2012 @ 5:11 PM

  92. “After all, that particular apple might be falling because of sunspots.”

    Only if sunspots generated a force between masses proportional to the mass, and inversely proportional to the square of the distance between them, and counter the measurable gravitational force that isn’t sunspot dependent. (If one hangs two bowling balls at the ends of a beam with a long fine wire, and moves another bowling ball near one of the two suspended balls, the torsion caused by the attraction of the suspended and fixed masses can be measured – and it is independent of sunspots.)

    Likewise, any alternate cause of global warming has to warm the troposphere and cool the stratosphere, decrease the diurnal temperature variation, and some of the polar amplification (the amount due to the continuing radiative transfer effects of CO2 after sunset, whether daily or at the beginning of polar winter; visible wavelength albedo changes have no effect in the dark – which eliminates the sun, or cloud albedo, or sun-GCR-cloud albedo interactions.)

    “…I think you step out of bounds by including attribution.”

    What sort of Alice in Wonderland cause could mimic CO2 in causing the observed global warming changes, cancel the physics of CO2 IR absorption/emission in the atmosphere, but leave CO2 laser physics unaffected? Hytran calculations for triatomic H2O, triatomic CO2, triatomic O3, taking into account the appropriate masses, bond strengths, and molecular configuration don’t have different first principles; they give results that support AGW. What’s left – right wing, tea party, anti-science, Karl Rove “we create our own reality” fairy dust?

    Comment by Brian Dodge — 1 Feb 2012 @ 5:14 PM

  93. “BPL, I am not sure that you understand input/output testing.”

    Sure he does.
    Input – ~30Gt/a CO2 FF emissions:

    Intermediate step 1 – DpCO2/Dt ~1.5ppmv/a since 1962, ~1.8ppmv/a last 20 years, CO2 concentration has risen from 317ppmv to 392ppmv:
    Intermediate step 2 – DT(Best)/dt ~0.024degC/a, ~1.17 degC since 1962: (see this)

    Output(s) –
    sea ice melt”” and accelerating glacier loss”
    http://www.bom.gov.au/climate/current/statements/scs31.pdf Wettest March on record in Australia
    http://www.bom.gov.au/climate/current/statements/scs26b.pdf Record wet January brings unprecedented flooding to northwest Victoria
    http://www.bom.gov.au/climate/current/statements/scs18b.pdf Exceptional winter heat over large parts of Australia
    http://www.bom.gov.au/climate/current/statements/scs14.pdf Six years of widespread drought in southern and eastern Australia, November 2001 to October 2007
    http://www.bom.gov.au/climate/current/statements/scs10a.pdf Climate conditions preceding the December 2006 southeast Australian bushfires Issued 19th December 2006
    http://en.wikipedia.org/wiki/2003_European_heat_wave “The 2003 European heat wave is one of the hottest summers on record in Europe, especially in France. The heat wave led to health crises in several countries and combined with drought to create a crop shortfall in Southern Europe. More than 40,000 Europeans died as a result of the heat wave.”
    http://www.guardian.co.uk/environment/2005/jul/11/weather.france “Jul 11, 2005 … France is facing its worst water shortage since 1976″
    http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=18509 “It was not even officially summer in the Northern Hemisphere, but Pakistan was in the midst of a deadly heat wave when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured the top image on June 10, 2007. ”
    http://climateprogress.org/2010/06/01/record-heat-wave-may/ “‘Hellish heatwave’ in Pakistan sets hottest temperature in Asia’s history, 53.5°C (128.3°F); in India, hundreds die, death toll expected to rise as record temperatures soar up to 122°F – June 1, 2010″
    http://www.bloomberg.com/news/2010-08-10/russia-may-lose-15-000-lives-15-billion-of-economic-output-in-heat-wave.html “Russia’s record heat wave may already have taken 15,000 lives and cost the economy $15 billion as fires and drought ravage the country.”

    Not exactly what I would call Non Destructive Testing – YMMV.

    Comment by Brian Dodge — 1 Feb 2012 @ 6:09 PM

  94. Kevin McKinney, #86:

    You say I am confused although I don’t see where you have contradicted me. Everything you write appears to confirm my understanding. You write, “the stratospheric cooling actually observed is evidence that the greenhouse effect is now active – since there is no other cause for the total observed stratospheric cooling”. There are a number of observations that confirm the correctness of the greenhouse effect. There is likewise no other cause for spectroscopic observations of absorption of radiation than increasing CO2. Is there something special about stratospheric cooling or is it just another proof of the greenhouse effect?

    Comment by Alex Harvey — 1 Feb 2012 @ 7:42 PM

  95. scienceblogs.com/stoat/2011/09/why_does_the_stratosphere_cool.php

    with appropriate caveats, see the full post for those,

    “… the reason that the real atmosphere has a stratosphere is because of ozone absorbing UV, thereby warming that portion of the upper atmosphere;

    hence the stratosphere is considerably warmer than it would be under just longwave (LW, or infra-red, IR) forcing; and CO2 is only effective in LW frequencies;

    hence, increasing CO2 increases the stratospheres ability to radiate in the LW, but doesn’t substantially increase its ability to gain heat, because most of that comes from the SW;

    hence it cools….”

    Comment by Hank Roberts — 1 Feb 2012 @ 8:48 PM

  96. Or, of course, you can read the comments – one of the more interesting attempts at putting complicated physics into words.

    The key point for attribution is what Gavin says there later:

    “Stratospheric cooling at the same time as surface warming was predicted with the first 1-dimensional model published over 40 years ago – decades before the data came in and any trends could have been discerned. This is precisely how science gains credibility – observe, theorise, predict, confirm….”

    That doesn’t say why the prediction was made — it’s complicated, takes math and modeling. See Spencer Weart about why computer models were needed to begin to understand this stuff.

    The models don’t generate explanations in simple English.

    Got calculus?

    Comment by Hank Roberts — 1 Feb 2012 @ 8:59 PM

  97. #83 Alex,
    Maybe you’ve missed the difference between evidence that can be used to determine sensitivity and evidence for a stronger greenhouse effect from CO2.
    Sensitivity is uncertain among other things because of the various effects clouds could be having on surface temperatures. Stratospheric cooling doesn’t tell you how clouds work.

    I guess stratospheric is special in that it’s clearer evidence than tropospheric heating on its own. But it’s only a piece of the puzzle.
    If you search the site, you’ll find lots of old comments from people struggling to understand stratospheric effects in detail.

    Comment by Anonymous Coward — 1 Feb 2012 @ 9:23 PM

  98. From what I’ve seen, Dr. Curry can be characterized as emphasizing uncertainty, but only talks about the side that says, “It might not be that bad.”

    If I were a clinician, I could say that the mind often retreats from information that it finds too painful. Mothers refuse to accept that a child has died, people refuse to accept that they have a terminal disease, etc. If there were a person too well trained in the physical sciences to tolerate the cognitive dissonance that would result from a belief in something not physically possible, but unable to accept the most likely outcome, they might retreat to the periphery of what is likely. Uncertainty and wide confidence intervals would be their friend. Their subconscious would keep them away from the other side that says, “It might be that bad or worse.”

    I’m not a clinician, and I’ve never met Dr. Curry, but that is my working model that explains her behavior, and allows me to preserve my belief that most people are honest and good, if perhaps a bit irrational.

    Eric,
    Nice explanation of a model. I sometimes explain that d = g*t^2/2, where g is 9.8m/s/s, is a model (distance traveled of a falling body) that can be proven wrong by anyone with the equipment to take accurate enough measurements of time and distance. That does not mean it is not useful.

    Comment by Chris G — 1 Feb 2012 @ 10:03 PM

  99. #94 Alex Harvey

    Is there something special about stratospheric cooling or is it just another proof of the greenhouse effect?

    Yes, there is something special about stratospheric cooling. The vertical profile of temperature change is one of the lines of evidence for human caused global warming.

    If it were solar forcing and not and increase in greenhouse gases such as CO2, the warming would be more evenly distributed through the vertical profile.

    But since we know we have thickened the CO2 sweater that keeps Earth warm, and we see that it is getting warmer near the surface of Earth and cooling in the stratosphere, that is a great indicator that the problem is an increase in CO2 in the troposphere that prevents heat from escaping, thus warming the lower atmosphere and cooling in the stratosphere due to the trapped heat in the troposphere.

    There are no other identified mechanisms that can do that… unless you’ve found something?

    Comment by John P. Reisman (OSS Foundation) — 1 Feb 2012 @ 10:13 PM

  100. #95, #96, #97, #99:

    Thanks for all the responses.

    Hank Roberts, I see this one’s difficult even for the experts, but I do note that the models we are talking about are the radiative transfer codes – correct? These models are just models of the basic physics. We all know they give the right answer and do not contain the parameterisations and tunings that cause skeptics to doubt the GCMs. And the GCMs in turn agree with the radiative transfer codes simply because they have built in radiative transfer codes of their own. Right?

    AC, I haven’t missed the difference between evidence that can be used to determine sensitivity and evidence for a stronger greenhouse effect from CO2. That is precisely what I said: as added CO2 is known to lead to cooling in the stratosphere is a fundamental result of the physics of radiative transfer it does not help us to distinguish between competing hypothetical explanations for observed global warming. It simply tells us what we already know – that we are pumping CO2 into the atmosphere and the theory of the greenhouse effect is sound.

    John P. Reisman, you write “If it were solar forcing and not an increase in greenhouse gases such as CO2, the warming would be more evenly distributed through the vertical profile”. Yes, but are comparing apples and oranges. A model forced by solar that is NOT ALSO forced by CO2 and ODSs is not relevant. As I said in #83, in order for the observed stratospheric cooling to be useful in distinguishing between competing hypotheses you would need to build a chemistry climate model with low climate sensitivity (e.g. 1.5 K) and force that with increased TSI + observed GHG and ODS changes and THEN compare the modelled vertical heat distribution with observations.

    I bet no one has ever done this before? And I also bet that the reason no one has ever done it before, if I am right, would be that no one expects that such an experiment would reveal anything surprising.

    Comment by Alex Harvey — 2 Feb 2012 @ 2:46 AM

  101. #94–
    I knew my previous comment was not as clearly written as I’d hoped, so let me try again.

    Alex, you had written:

    “These features all would occur whatever the cause of the observed warming at the surface and in the oceans.”

    That’s not correct. For instance, had surface warming been due to increased insolation, or decreasing albedo, we would not see stratospheric cooling.

    Your later comments seem quite bizarre to me, if you will forgive the blunt characterization. They seem to amount to saying that there are multiple “proofs” of the greenhouse effect, but that they don’t prove anything.

    But there’s a problem for your idea: the modeled stratospheric cooling can’t be separated from the warming at lower levels. If you throw out the latter, you also throw out the former. Similarly for the other issues: current understanding implies warming. Throw out the implied warming and you also throw out the understanding.

    Oh, and by the way, climate sensitivity isn’t programmed into most models–it’s an emergent property. So your suggestion “to build a chemistry climate model with low climate sensitivity” would be, at least, non-trivial.

    Comment by Kevin McKinney — 2 Feb 2012 @ 9:14 AM

  102. Brian,
    I think you are suffering from the same lack of input/output understanding as BPL. To say a given input will result in a certain output, it must produce that same output, each and every time. A one-time occurrance cannot be attributed to a specific input, if it is not repeatable. This is precisely why scientists attempt to duplicate other scientists work.

    Comment by Dan H. — 2 Feb 2012 @ 9:21 AM

  103. #100 Alex Harvey

    Prof. Held seems to be saying that the existence of stratospheric cooling tells us nothing about the sensitivity of the climate to increasing greenhouse gases. If there were strong negative feedbacks that prevented the surface from warming, the stratosphere would cool just the same. If so, I fail to see why stratospheric cooling is even mentioned in the context of attributing global warming.

    This statement does not make sense. It sounds like gobbledygook to me. If there were a strong negative feedback you would see a different pattern of cooling in the vertical profile than we are currently seeing. The fact of tropospheric warming and stratospheric cooling matches what would happen if you put a blanket in the troposphere trapping heat.

    In other words Prof. Held(? where’s his paper) is saying if the Earth cooled the troposphere and the stratosphere would cool. Of course that makes sense. But what does that have to do with human induced warming?

    Look, I’m a skeptic. In fact I’m so skeptical I only sometimes trust peer reviewed papers. I’ll tell you what I do trust though… those papers that survived peer response. Right now you are presenting a tentative hypothesis that sounds like it’s based on an untested idea. That is meaningless until you prove it. So why don’t you write the paper?

    Otherwise you are selling snake oil to the masses, and that is not science.

    As to Ozone Depleting Substances… Do you really think the science is not examining that??? Have you read any IPCC reports? Have you dug around to catch up on the literature in attribution? If you have, you have not dug deep enough.

    Comment by John P. Reisman (OSS Foundation) — 2 Feb 2012 @ 11:32 AM

  104. Alex says:
    As I said in #83, in order for the observed stratospheric cooling to be useful in distinguishing between competing hypotheses you would need to build a chemistry climate model with low climate sensitivity (e.g. 1.5 K) and force that with increased TSI + observed GHG and ODS changes and THEN compare the modelled vertical heat distribution with observations.

    Alex, the TSI has been observed to not change significantly during the age of satellites. As I understand it it’s changed enough to quantify temperature anomalies during the solar cycle, but not anywhere near enough to explain the observed warming trend.

    IOW, if you actually run the model you propose and vary TSI according to actual observations you don’t get the results you pretend to expect.

    If you want to create a model that uses observed atmospheric changes and varies TSI just for fun, go right ahead. It’s not useful in the real world unless you can show that TSI actually *has* changed significantly.

    Really, try to do something better than throwing innuendo about not running models there’s no reason to waste time on and pretending it means something.

    And while you’re proposing ‘competing hypothesis’ you might try actually citing one that’s consistent with actual observations. You know, actual CO2 levels, actual TSI, actual observed temperature changes. Explaining historical data would be good too: any ‘competing hypothesis’ constraining sensitivity to 1.5 degrees also needs a mechanism to explain paleoclimate. As a free clue for you, that’s, uhm, extremely difficult to do with a sensitivity much below 3.

    Comment by David Miller — 2 Feb 2012 @ 11:38 AM

  105. Alex Harvey,

    as added CO2 is known to lead to cooling in the stratosphere is a fundamental result of the physics of radiative transfer it does not help us to distinguish between competing hypothetical explanations for observed global warming.

    I don’t understand your logic here. The case for the observed global warming being caused by CO2 is based on the same physics of radiative transfer which says adding CO2 causes the stratosphere to cool. So why do you accept one cause and effect but not the other?

    Comment by andrew adams — 2 Feb 2012 @ 12:09 PM

  106. Also, what are the other “competing explanations” for the observed global warming?

    Comment by andrew adams — 2 Feb 2012 @ 12:12 PM

  107. Stratospheric ultrafast confusion –

    It started @ 20 with a reference to
    http://www.gfdl.noaa.gov/blog/isaac-held/2012/01/21/22-ultra-fast-responses/

    0. Ultrafast responses are not the only responses.

    1. Suppose as in the excellent post by Isaac Held that atmospheric CO2 is instantly doubled.
    This changes the radiative properties of the atmosphere. This in turn has consequences, and some of them happen quite quickly.

    2. One of these quick responses is stratospheric cooling, which is caused as follows:
    a. The stratosphere is heated by UV from the sun, absorbed by O3 (ozone). The stratosphere loses energy (cools) by radiating IR. The famous greenhouse gasses including O3 and CO2 do this. CO2 does not pick up UV energy directly. Instead CO2 gains energy from collisions with O3 – and then CO2 radiates the energy away. So, more CO2, more cooling.

    3. But the stratosphere is also warmed by IR from either above or below. Suppose there came to be less IR coming from below. The stratosphere would cool (other things being equal, which they never are).

    4. Now suppose we increase atmospheric CO2 slowly. As we know, the surface environment warms and the oceans acquire much more energy. Hence there must be less IR going from below to the stratosphere. (Conservation of energy you know). So, stratospheric cooling again.

    Comment by Pete Dunkelberg — 2 Feb 2012 @ 2:46 PM

  108. Very interesting discussion.
    I have another climate 101 question for the experts here, concerning the attribution:
    How can you differentiate between H2O and CO2, when trying to find CO2 greenhouse effect?
    I mean most of the greenhouse effect is due to H2O, due to the feedback effects.
    So what is the fondamental difference between co2 and water that i am missing?
    Could stratospheric cooling be caused by increased water vapor in the troposphere, whatever the cause of this increase?
    Thanks.

    [Response: The stratosphere is mostly affected by concentrations of GHGs in the stratosphere – and that is dominated by CO2 and O3. H2O in the stratosphere is much less than CO2 in abundance, so while it does have an impact, the very small changes (relatively speaking) can’t explain the temperature changes. For instance, strat water vapour goes from ~3 ppmv to 7 ppmv as you go up (increasing because of CH4 oxidation). CO2 is 390 ppm (i.e. 6 to 10 times more). The change in H2O from increases CH4 is a couple of ppm at most, changes because of dyanmics/trop/strat exchange maybe 1 ppm. Changes in CO2 have been over 100 ppm. Even when you factor the radiative effectiveness into it, the changes in CO2 make by far the biggest difference – particularly in the mid to upper-stratosphere. – gavin]

    Comment by Romain — 2 Feb 2012 @ 4:12 PM

  109. I was looking at the ‘Prof. Held’ statement again. As with so many bad arguments, people set up a hypothetical that has no basis in fact and then say see we don’t know. It’s a straw man argument, but a pretty weak one.

    Comment by John P. Reisman (OSS Foundation) — 2 Feb 2012 @ 7:05 PM

  110. Gavin said:

    “For instance, strat water vapour goes from ~3 ppmv to 7 ppmv as you go up (increasing because of CH4 oxidation). CO2 is 390 ppm (i.e. 6 to 10 times more).”

    How is that 6 to 10 times more? (Sorry if I’m being dense, but at least I’m paying attention.)

    [Response:Sorry, I’m the one being dense. I shouldn’t blog on the run … say 60 to 100+ times as much, instead. – gavin]

    Comment by Kevin McKinney — 2 Feb 2012 @ 10:26 PM

  111. For anyone who has the tangential interest, one “Alex Harvey” advanced some ideas at Deltoid a few months ago, starting at #1. Almost all of the 700+ comments on that thread were related to that poster and a shifting set of claims (e.g. #485), at least one of which was based on his use of a term that he refused to define for the majority of the thread.

    On that post #46 points out that “…there are at least three Alex Harveys (or Alexander Harveys) who post in climate change forums…” so this Alex Harvey might not be that one. I note that that poster declared he trusted scientists based in part on likability and (ahem) held up Isaac Held as someone who he would trust (#74) because (amongst other reasons) “He doesn’t delete embarrassing posts because when he doesn’t know the answer as at RealClimate – just tells it the way he sees it.” He made various claims about various papers etc. – but also revealed a number of very fundamental errors of understanding and execution that suggest that his interpretation of more sophisticated issues may not be entirely accurate. He clung the concept that it is very likely that there are unknown factors such as (#632) large but hitherto unknown internal variability cycles (or forcings) that might render actual climate sensitivity quite low – despite the lack of evidence for such cycles/forcings, and the existing explanations doing rather well…

    …and that poster was referred more than once to RealClimate to benefit from expert discussion (even as it was noted that he quote-mined from RealClimate when it suited him).

    Comment by Lotharsson — 3 Feb 2012 @ 12:59 AM

  112. Dan H.: “To say a given input will result in a certain output, it must produce that same output, each and every time.”

    Whiskey, Tango, Foxtrot? So by your definition, we can’t do physics on anything more complicated than the collision of two billiard balls? Dude, you really need to catch up.

    Comment by Ray Ladbury — 3 Feb 2012 @ 9:31 AM

  113. Ray,
    The entire input/ouput discussion started with post #34, where it was stated that climate science does not have the luxury of input/output testing. This is generally true, as variables cannot be held constant, but are changing continuously. Jumping from input/output testing to suggest that we cannot do physics on the climate is quite a stretch, to say the least. Physics is much more that just the collisions between two objects.
    If you have a method of measuring the effect on the Earth’s climate of changing only one variable, while holding all the others constant, I am all ears. Until then, input/output testing cannot be performed.

    Comment by Dan H. — 3 Feb 2012 @ 9:57 AM

  114. Ray, if you get in an argument with Dan H., he wins, because new readers unfamiliar with his tactics will not be able to tell which of you is confusing things and pretending to be a scientist.

    “A control variable is a variable that effects the dependent variable. When we ‘control a variable’ we wish to balance its effect across subjects and groups so that we can ignore it, and just study the relationship between the independent and the dependent variables.”
    http://www.sahs.utmb.edu/pellinore/intro_to_research/wad/vars_hyp.htm

    Comment by Hank Roberts — 3 Feb 2012 @ 10:41 AM

  115. Dan H., Your conception of science is about 80 years out of date. It would appear that you would deny that biology, ecology, geology, climate science–indeed most of modern science–is science. And yet they work. Complexity does not preclude science.

    Comment by Ray Ladbury — 3 Feb 2012 @ 12:04 PM

  116. Hank,
    Wow! Is it my imagination, or did you actually agree with me for once. I guess there is a first time for everything.

    Comment by Dan H. — 3 Feb 2012 @ 12:05 PM

  117. The arrogance of those who use their guest status in these comments to “teach” others science that does not hold up is staggering.

    I would hope they would try to open their minds a bit and actually learn something, since that is what this board is supposed to be for.

    Comment by Susan Anderson — 3 Feb 2012 @ 12:58 PM

  118. > Dan H
    suggests it’s necessary to have
    > “a method of measuring … changing only one variable,
    > while holding all the others constant ….”

    Bunk.

    Experimental design copes with such variables that can’t be held constant.

    Dan then uses his debating ploy again: ignore being shown wrong; claim response to correct his misstatement amounts to agreeing with him.

    “blah blah blah blah blah Ginger blah blah blah ….”

    Plonk.

    Comment by Hank Roberts — 3 Feb 2012 @ 12:59 PM

  119. Complexity? Who needs it?

    One of the first labs in 1st semester physics is to slide a block of wood down an inclined plane that is part of a protractor. You put the block on the plane when it is close to horizontal, then gradually increase the slope until the block slides down. Do it repeatedly until you think you have enough data, or until time runs out. In writing this up you should show understanding
    1. of how the downward force of gravity yields a resultant smaller force parallel to the inclined plane
    2. that no matter how careful you are, the block slides at quite different angles.

    Comment by Pete Dunkelberg — 3 Feb 2012 @ 1:04 PM

  120. Ray,
    Really! It amazes me how you can leap to such crazy conclusions. Complexity is irrelevant. The scientific method works from the simplest up to the most complex systems.

    What Matt, Hank, and myself have been referring to is to control certain variables, while changing an input, and observing the output. This is much easier done in vitro than in vivo.

    Just because technology has allowed us to analyze more complex systems in ways scientists of the past centuries never dreamed of, does not mean that the scientists of old would deny the science of today. It appears that you are the only in denial; specific with regards to methodolgy.

    Comment by Dan H. — 3 Feb 2012 @ 1:16 PM

  121. re. Dan H. and his posts:

    It seems he can’t see the big picture no matter how many times he is informed on specific issues and relevance factors. His mind may be filtering out the relevant information preventing him from seeing the big picture or he is for some odd reason practicing the art of obtuscation – new word copyright John Reisman :)

    Maybe some posts should come with a new obtuscation label as a guide for new readers!

    Comment by John P. Reisman (OSS Foundation) — 3 Feb 2012 @ 1:26 PM

  122. It is amazing how dense some people can be. Does anybody here do any real science any more? By the content of that last few post, I have to seriously question whether them (Pete appears to understand science).

    Equating a simple experiment with the “big picture” seems absurd in all aspects.

    Comment by Dan H. — 3 Feb 2012 @ 1:40 PM

  123. Dan H., In systems where control of a single variable is not possible for whatever reason, a well verified model can be used to accomplish the same purpose. Any more, systems of the type you are discussing are the minority. That’s not how science gets done anymore. This isn’t fricking chem lab.

    Oh, and Dan, when was the last time you published a peer-reviewed paper?

    Comment by Ray Ladbury — 3 Feb 2012 @ 2:19 PM

  124. Dan H.”Hank,
    Wow! Is it my imagination, or did you actually agree with me for once. I guess there is a first time for everything.”

    Dan, all of your victories are in your imagination.

    Comment by Ray Ladbury — 3 Feb 2012 @ 2:25 PM

  125. > What Matt, Hank, and myself have been referring to

    Dan pretends corrections are agreement.
    Dan is debating imaginary friends.

    Boring, deeply boring.

    Comment by Hank Roberts — 3 Feb 2012 @ 2:28 PM

  126. Hank @ 118 “blah blah blah blah blah Ginger blah blah blah ….”

    YES, not only apropos to Dan H, but a fantastic Farside reference. I just wanted to let Hank (who I enjoy reading on this board) know that someone got the joke. Woof!

    Comment by Ginger — 3 Feb 2012 @ 2:47 PM

  127. Gavin, thank you for your (quick!) response.
    So the basic thing i missed is that the stratospheric cooling is primarily caused by ‘more IR out radiation by more CO2 + less UV absorption by less O3′ rather than ‘less upcoming IR from the troposphere due to more GHG’

    Any post/paper on the quantification of each of these causes? Thanks again.

    Comment by Romain — 3 Feb 2012 @ 3:58 PM

  128. #122 Dan H.

    Your wrong. Here’s why. You present your arguments as if they are significant to ‘climate science’ as a whole somehow by inference (whether you admit it or not that is the effect). Focusing on any single experiment is lame at best and incredibly stupid at near worst. There are even worse aspects to your obtuscation though.

    Climate science is not about a single experiment and your narrow-minded focus distracts people from the truth of the ‘big picture’.

    Climate science, as in all science, is about how the single experiments affect, the bigger picture. You still cant see the forest because there are all these trees in your way.

    As to who is dense, look in a mirror. I know, I know, you won’t be able to see your density because you are in the way.

    Comment by John P. Reisman (OSS Foundation) — 3 Feb 2012 @ 4:26 PM

  129. John,
    All your insults aside, I was not the one being narrow minded.
    My point has been that climate science is not a simple input/output experiment, and that drew the ire of many posters here. Now, ironically, you are arguing my point as if it goes against what I am trying to say. Maybe you should stop listen to the other posters here, especially those who seem to exemplify your final paragraphs.

    [You’re once again repeatedly saying nothing of importance and wasting peoples’ time in the process. Contribute something worthwhile or have your comments deleted]

    Comment by Dan H. — 3 Feb 2012 @ 6:27 PM

  130. Addendum to my analysis of Dan H.’s perspective:

    To those that are interested in understanding ‘real science’ the big picture is the sum of all the little pictures (experiments, observations, physics, etc.) and from the big picture comes more relevant understanding.

    Climate science has many facets and all the evidence points to human induced warming. So in all its complexity, it’s as simple as that. Those that have too much density or filters will miss the main point and by inference Dan H. seems to keep missing the point because of his narrow-minded view. Don’t be ‘tricked’ by his obfuscation and keep your focus on what the ‘real science’ is telling us.

    Comment by John P. Reisman (OSS Foundation) — 3 Feb 2012 @ 7:03 PM

  131. Dan H., No one is trying to say climate science is not complex. What we are saying is that complexity does not preclude attribution. There is no reason why science or attribution require a simple analysis with control of all variables. Indeed, in some fields (e.g. ecology), such an approach shortchanges the subject matter and actually fails to predict the system behavior.

    Look at what control of variables is trying to accomplish, and then think how the same goal can be accomplished when it is not possible. That is how science is extending its reach.

    Comment by Ray Ladbury — 3 Feb 2012 @ 9:02 PM

  132. #129 Dan H.

    Pot meet Kettle. Dan, you say others that point out the fallacies in your posts are ‘dense’ and then when you are called on it you say people are insulting you.

    There is a bible quote that applies here. Don’t try to remove the splinter from your friends eye until you remove the log from your own.

    Comment by John P. Reisman (OSS Foundation) — 3 Feb 2012 @ 9:48 PM

  133. John,
    Are you implying that you are the kettle?

    Don’t you find it a bit ironic that you are now carrying the torch I started when I claimed that climate science was not a simple input/output test (technically Matt started it (#34), but I reinforced it). You claim that I am wrong, then seem to repeat my claims. You talk about missing the forest for the trees, but that seems to be what people are doing when they argue for simple testing. I have been arguing that the situation is more complex. You appear to be arguing the same, but claim it is not. I am sure you understand my position on this.

    I find it rather humorous that the moderator seems to think my comments are not important, but those who sling mud, make jokes, or add other inane comments are somewhat vitally important to this discussion. If this is where climate science is headed, it is no wonder that support is waning.

    Comment by Dan H. — 3 Feb 2012 @ 11:35 PM

  134. “If you have a method of measuring the effect on the Earth’s climate of changing only one variable, while holding all the others constant, I am all ears.”

    Climate models.

    If you push on a thing hard enough, it will break. If you only have one thing, and you push on it til it breaks, you can’t claim that you didn’t break it because the experiment can’t be repeated, and it might have been just natural variation. We are pushing really hard on our only climate system, and it will eventually break; not a question of whether, but when.

    And you can’t really do “identical” experiments on even simple systems like bouncing billiard balls, since the balls, and the momentum, and the position are only known as well as can be measured; measurements are never perfectly identical.

    Comment by Brian Dodge — 4 Feb 2012 @ 4:17 AM

  135. Kevin McKinney, #101:

    I am wondering if there is some semantic confusion concerning the distinction between the “greenhouse effect” and the “enhanced greenhouse effect”. I will clarify my own understanding.

    I don’t believe there is any argument or uncertainty over the greenhouse effect itself. That there is a “greenhouse effect” has been known since the time of Jean Baptiste-Joseph Fourier in the 18th century and John Tyndall in the 19th century. Tyndall demonstrated empircally the absorption of radiation by atmospheric carbon dioxide.

    There is so little to disagree about in the basic theory of the greenhouse effect that Richard Lindzen and Kerry Emanuel could happily co-author an encyclopaedia article together on the subject in 2002:

    R.S. Lindzen and K. Emanuel (2002) The greenhouse effect. in Encyclopedia of Global Change, Environmental Change and Human Society, Volume 1, Andrew S. Goudie, editor in chief, pp 562-566, Oxford University Press, New York, 710 pp.

    That’s worth reading, by the way, just to see how much Lindzen and Emanuel agree on. Anyhow, I take the greenhouse effect to be about as certain as gravity.

    The “enhanced greenhouse effect” is quite another matter. (And I’m sure that Lindzen and Emanuel disagree passionately here.) While no one questions the greenhouse effect, there is much argument and uncertainty once “feedbacks” are included. This is mostly what the global warming controversy is about.

    Now as far as I can tell, these “feedbacks” are theories in their own right. In order to estimate how much of the recent warming is the result of natural causes and how much is the result of CO2 emissions, the uncertain theories about feedbacks are combined with the certain theory of the greenhouse effect (and of course plenty of other theories).

    Climate sensitivity is the equilibrium response to a doubling of CO2 after assuming the Planck response greenhouse effect + the theory of the water vapour/lapse rate feedback + the various theories of the cloud feedbacks. And depending on which definition of climate sensitivity you are using, you may also include the snow-ice-albedo feedback, vegetation feedbacks and probably others.

    Now let me stress that I am not trying to validate the objections of climate change skeptics. It is the IPCC AR4 “very likely” range of climate sensitivity that is (I think) 1.5 K to 6 K and the “likely” range 2 K to 4.5 K. At the 1.5 K end, the warming problem is not that serious. And at the other end, it’s catastrophically serious. And the reason for the discrepancy is uncertainty over the “feedbacks” – uncertainty over the “enhanced greenhouse effect”. Without feedbacks, there would be no uncertainty.

    So do we agree so far?

    Now… In order for stratospheric cooling to be relevant to attribution – one would think – there would need to be an argument that the magnitude of CO2-caused stratospheric cooling is related in some way to the magnitude of CO2-caused warming at the surface. If not, then appeals to stratospheric cooling as evidence that humans are causing the warming at the surface would not make any sense. Observations of stratospheric cooling would simply be more proof that CO2 levels have increased – which is not disputed.

    Now Isaac Held is a climate science veteran and certainly no skeptic. Yet the statement at his blog implies that the rate of stratospheric cooling bears no relationship at all to the greenhouse warming at the surface. I immediately wondered, then how on earth can it be relevant to attribution of warming at the surface? I have asked the question here and received no straight answers. Next stop, I may just ask Prof. Held himself.

    Finally, I note that you say building a low sensitivity GCM might be difficult. Well, some of the IPCC climate models already have sensitivities as low as 2.1 K. And without the positive cloud feedbacks they would apparently have a sensitivity of 1.9 K +/- 0.15 K (AR4 Chapter 8). So, I guess you could easily build a low sensitivity model by simply taking out the clouds. Or one could build a parameterisation of Lindzen’s Iris, as proposed in the original Lindzen et al. 2001 Iris paper.

    I do hope this is a bit clearer.

    Comment by Alex Harvey — 4 Feb 2012 @ 8:53 AM

  136. Lotharrson, #111:

    I am the same person who posted in the Deltoid thread. I am at pains to distinguish myself from the other Alexander Harvey who posts more frequently than I do and appears to have a physical sciences background and a deeper understanding of climate science that I do. Having googled myself, though, I have found many posts by posters named Alex Harvey that certainly aren’t me and I doubt they are the other Alexander Harvey. Thus, I believe there are at least three of us. I live in Syndey, Australia. I am a computer programmer and have an honours degree in history and philosophy of science. I am the Wikipedian of the same name. I have been teaching myself climate change science for about six years.

    How about you? ;-)

    Comment by Alex Harvey — 4 Feb 2012 @ 9:23 AM

  137. As the main post says:

    “Now let’s put some real numbers in here. Attribution is fundamentally a modelling task, and the principal models that can be used are the coupled GCMs – at least to start with.”

    Comment by Hank Roberts — 4 Feb 2012 @ 10:02 AM

  138. #133 Dan H.

    I will be direct.

    1. First, thank you for proving my point that you have a high density factor when if comes to learning.
    2. Your arguments are ambiguous fluff.
    3. I’m not saying it’s complex actually I’m arguing that it’s simple. More CO2 traps more heat, less CO2 traps less heat.
    4. Your comments are not important as they rarely have substance.
    5. Are you sure you’re not a politician… your spin factor is rather high.

    MORE CO2 = MORE TRAPPED HEAT.

    If you still think it’s more complex than that after all the evidence is weighed then you are still missing the point.

    Clouds, aerosols, albedo, RF, temperature, natural variation, atmospheric constituents, fossil fuel output, attribution, volcanoes, solar, GCR’s, Iris Effect… all weighed and measured. We are warming and humans have imbalanced the radiative forcing of Earth.

    Comment by John P. Reisman (OSS Foundation) — 4 Feb 2012 @ 11:04 AM

  139. #135 Alex Harvey

    1. Enhanced is just enhanced (we added some CO2, CH4 and N2O, which is warming the oceans and increasing the H2O.
    2. I did a 60 second video on the History of Climate Science with Spencer Weart’s help: http://ossfoundation.us/
    3. The controversy about feedbacks in the peer reviewed/responded literature is largely not if they exist or if they are more positive or negative, but rather how strong re. how much warming to expect.
    4. Feedbacks are not hypothetical. It is safe to say that without feedbacks, we probably could not get in or out of ice ages as easily as we do.
    5. stratospheric cooling = put on a jacket and you trap more heat by radiating it back to your body, thus not allowing it to escape, thus cooling above your jacket (less heat escaping)…

    Comment by John P. Reisman (OSS Foundation) — 4 Feb 2012 @ 11:06 AM

  140. Alex Harvey, Ah, you make a distinction between the greenhouse effect and the “enhanced greenhouse effect”. Do you also distinguish between macro- and micro-evolution? Because these distinctions have equal validity.

    You would not get 33 degrees of warming from the greenhouse effect without positive feedbacks. We know with 100% certainty that many of the feedbacks are operative. You cannot make a climate model work without significant positive feedback. I am curious why you think that positive feedbacks magically stop when you reach a concentration of 287 ppmv?

    The fact of the matter is that you simply cannot understand Earth’s climate over the eons without such positive feedbacks. The inability of minds like Lindzen’s, Spencer’s, etc. to do so is a direct result of their rejection of such feedbacks.

    Comment by Ray Ladbury — 4 Feb 2012 @ 11:21 AM

  141. Alex Harvey

    Just found this in:

    Southern Hemisphere Atmospheric Circulation Response to Global Warming
    PAUL J. KUSHNER, ISAAC M. HELD, AND THOMAS L. DELWORTH
    NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey
    (Manuscript received 24 February 2000, in final form 1 August 2000)

    At upper levels, the temperature response in Fig. 7b has other features that are familiar from previous greenhouse-warming integrations [e.g., Mitchell et al. (1990), Fig. 5.2]. These include the maximum in warming in the tropical upper troposphere associated with a shift of the tropical temperature profile to a warmer moist adiabat and the stratospheric cooling associated with enhanced CO2 concentrations.

    Can you point me to where Prof. Held says: “the existence of stratospheric cooling tells us nothing about the sensitivity of the climate to increasing greenhouse gases.”

    Comment by John P. Reisman (OSS Foundation) — 4 Feb 2012 @ 11:54 AM

  142. Alex Harvey,

    “So do we agree so far?”

    I wouldn’t put it that way but it seems we’re basically in agreement.

    “Now… In order for stratospheric cooling to be relevant to attribution – one would think – there would need to be an argument that the magnitude of CO2-caused stratospheric cooling is related in some way to the magnitude of CO2-caused warming at the surface.”

    No. It’s relevant, just not some kind of total proof.
    The cooling and the warming are necessarily related, just not by a simple or well-understood relationship.

    “Now Isaac Held is a climate science veteran and certainly no skeptic. Yet the statement at his blog implies that the rate of stratospheric cooling bears no relationship at all to the greenhouse warming at the surface.”

    You are the one implying that. Why don’t you quote the guy?
    This appeal to authority is bordering on dishonesty in my opinion.

    “So, I guess you could easily build a low sensitivity model by simply taking out the clouds. Or one could build a parameterisation of Lindzen’s Iris, as proposed in the original Lindzen et al. 2001 Iris paper.”

    I guess. But your model would match observations and reconstructions very poorly, would it not?
    So, as you implied earlier, it probably wouldn’t be worth building. :-)

    Comment by Anonymous Coward — 4 Feb 2012 @ 11:56 AM

  143. Harvey is misunderstanding Held currently at
    http://www.gfdl.noaa.gov/blog/isaac-held/2012/01/21/22-ultra-fast-responses/#comment-436

    Comment by Hank Roberts — 4 Feb 2012 @ 12:12 PM

  144. Although I may amend my current consideration as I try to understand this argument better. Isaac Held seems to be saying that the stratospheric cooling is not a feedback, but rather an ‘ultra-fast’ response.

    It does not seem that he is saying there is no connection between increased CO2 and stratospheric cooling.

    If my understanding increases I will amend.

    Comment by John P. Reisman (OSS Foundation) — 4 Feb 2012 @ 2:07 PM

  145. Alex, Having read your exchange with Prof. Held, I would say that it seems you are confused about the attribution argument. First, no one tries to determine CO2 sensitivity from stratospheric cooling. Instead the argument goes
    1)Stratospheric cooling demonstrates that the greenhouse effect of CO2 is nowhere near saturated.
    2)A dozen or so other independent lines of evidence demonstrate that CO2 sensitivity is roughly 3 degrees per doubling, with 90% CL between 2 and 4.5 degrees per doubling.

    I’d be careful about going to the 95% CL–a sensitivity above 5 degrees per doubling might as well read “GAME OVER”.

    Comment by Ray Ladbury — 4 Feb 2012 @ 3:38 PM

  146. AH 135: At the 1.5 K end, the warming problem is not that serious.

    BPL: Want to bet?

    Comment by Barton Paul Levenson — 4 Feb 2012 @ 5:26 PM

  147. At the 1.5 K end, the warming problem is not that serious.

    I’m not sure that’s a viable or relevant claim about the real world any more. In particular, check out the updated research (illustrated in that post) suggesting that “serious” is already present at 1 K of warming, and note that (regardless of the actual sensitivity) we’re already 80% of the way there and we haven’t reached equilibrium yet, which means 1 K warming is basically unavoidable.

    In order to estimate how much of the recent warming is the result of natural causes and how much is the result of CO2 emissions, the uncertain theories about feedbacks are combined with the certain theory of the greenhouse effect (and of course plenty of other theories).

    I don’t believe that’s necessary.

    Do the feedbacks of interest operate in response to all forcings or just anthropogenic ones? If the former, why do you think that confidence levels in the magnitude of various feedbacks influences attribution confidence? Isn’t is sufficient to measure all the significant forcings (and their confidence levels) and partition them into anthropogenic and natural? (I expect this question to raise your belief/hope as expressed on Deltoid that a significant chunk of recent warming is due to a hitherto unknown, reasonably large, slow pseudo-cyclic natural variation, or some other reasonably large unknown factor as long as it’s anything but anthropogenic.)

    Or one could build a parameterisation of Lindzen’s Iris…

    Unless I’ve missed something significant, the data clearly doesn’t support the hypothesised effect, so building such a parameterisation wouldn’t have any relevance to the climate system.

    Similarly taking out clouds because you are trying to (artificially) lower the sensitivity of the resulting model is not particularly smart. For one thing I would expect that to increase the uncertainty in emergent properties of the resulting GCM such as climate sensitivity thus failing in your apparent goal of a low sensitivity GCM. Lowering the most likely value but widening the uncertainty doesn’t suggest the problem is any less serious. For another thing, the point of GCMs is to model the significant aspects of the climate system with sufficient fidelity to be useful (which includes examining the climate sensitivity of the resultant model) rather than to achieve pre-determined values for some emergent properties at the expense of usefulness and fidelity.

    Comment by Lotharsson — 4 Feb 2012 @ 6:56 PM

  148. How about you? ;-)

    Engineering Ph.D., also in NSW Australia and working in the software industry, including some programming.

    I haven’t come across anyone else posting under my nym (with a double “s”).

    Comment by Lotharsson — 4 Feb 2012 @ 6:59 PM

  149. “In order for stratospheric cooling to be relevant to attribution – one would think – there would need to be an argument that the magnitude of CO2-caused stratospheric cooling is related in some way to the magnitude of CO2-caused warming at the surface.”

    You are conflating determination of cause with determination of sensitivity.

    I would add to John Reisman’s list –
    “5. stratospheric cooling = put on a jacket[CO2] and you trap more heat by radiating it back to your body, thus not allowing it to escape, thus cooling above your jacket (less heat escaping)… Adding energy from a heating pad [it’s the sun, it’s natural variability] can make you just as warm as putting on a jacket, but it will warm above you, the opposite sign of the effect of a jacket.
    Which means that surface warming has to be CO2, or something that traps heat in the same way. We know from isotope ratios the the additional CO2 has a fossil fuel signature, and that the rate of CO2 increase in the atmosphere is proportional to human fossil use – hence the attribution of the warming we see to human fossil fuel CO2 emissions. (Even if there is something that traps heat in the same way as CO2(right wing hot air, pixie dust), in order for it to be the reason instead of CO2, it would have to also simultaneously cancel the effect of CO2 in exact proportion. I can’t think of anything that has this behavior, and neither have the denialists – they just claim that there might be something not yet known.)

    That the warming of the troposphere accompanied by cooling of the stratosphere is a signature of AGW from CO2 doesn’t mean that we can understand precisely, or predict accurately, or measure exactly the transfer function for tropospheric warming to stratospheric cooling, since there are multiple factors which contribute to the stratospheric temperature – ozone, hydroxyl radical chemistry and its interaction with methane, solar UV variability which is different from visible solar variability, and other confounding factors. Because ozone is a major player, and the ozone levels vary with the rate of chlorofluorocarbon destruction, which since the Montreal protocols have been falling, the relationship between stratospheric cooling and CO2 tropospheric sensitivity might have been different in 1980 than now. This does not affect the sensitivity of tropospheric warming to increases in CO2.

    Comment by Brian Dodge — 4 Feb 2012 @ 10:07 PM

  150. Ray Ladbury, #145:

    You write,

    “The [attribution] argument goes
    1)Stratospheric cooling demonstrates that the greenhouse effect of CO2 is nowhere near saturated.
    2)A dozen or so other independent lines of evidence demonstrate that CO2 sensitivity is roughly 3 degrees per doubling, with 90% CL between 2 and 4.5 degrees per doubling.”

    So where is it said that stratospheric cooling is important because it shows that the greenhouse effect of CO2 is not saturated? I find this rather hard to believe. It has been known since the 1950s that the greenhouse effect is not “saturated”. For example, in the RealClimate post “A Saturated Gassy Argument” (Spencer Weart and Raymond Pierrehumber, 26 June 2007), I note that stratospheric cooling is not even mentioned. Instead, Dr. Weart argues that John Tyndall knew that the greenhouse effect is not saturated as early as 1862, and he then laments that scientists should have refuted the “saturation” argument of Knut Ångström in 1920s, if they had bothered to think it through.

    But you are right that I am confused about the attribution argument. It says in the IPCC AR4 SPM (“Understanding and attributing climate change”, p. 18):

    “Warming of the climate system has been detected in changes of surface and atmospheric temperatures in the upper several hundred metres of the ocean, and in contributions to sea level rise. Attribution studies have established anthropogenic contributions to all of these changes. The observed pattern of tropospheric warming and stratospheric cooling is very likely due to the combined influences of greenhouse gas increases and stratospheric ozone depletion. {3.2, 3.4, 9.4, 9.5}”

    What is missing in the AR4 is an explanation of why these various observations are relevant.

    I took this statement to mean that the “attribution studies” related to “warming of the climate system” and more broadly to “understanding and attributing climate change”. I never would have guessed that stratospheric cooling is largely irrelevant to understanding the surface warming. And I can see that others here have been confused by this too.

    Finally, you say in point (2) that there are about a “dozen or so” other independent lines of evidence that constrain climate sensitivity within the IPCC likely range. Well, these independent lines of evidence are exactly what I am interested in.

    Gavin has written,

    “Attribution is fundamentally a modelling task, and the principal models that can be used are the coupled GCMs – at least to start with.”

    Of course, it is often said that it is a “denialist myth” that anthropogenic attribution requires these GCMs. Well, I do know that Forster and Gregory (2006) attempted to use satellite observations to constrain climate sensitivity in a way that was truly independent of the GCM results. Of course, Forster and Gregory have been challenged by Lindzen and Choi (2011) who have argued that use of simple regression biases to a higher sensitivity. And I realise that Hoffert and Covey (1992), Hansen et al. 1993, and similar studies have used data from the last glacial maximum to constrain climate sensitivity, although as far as I can tell, the GCMs are still required to estimate the change in global mean temperature – so they are not truly independent of GCMs. And as the recent Schmittner et al. (2011) study has shown, there is still a lot of debate about the magnitude of the LGM cooling.

    So what I am missing? What are the other nine lines of independent evidence to make up your dozen?

    Comment by Alex Harvey — 5 Feb 2012 @ 9:23 AM

  151. Lotharsson, #147/8:

    Apologies for the typo. It’s a small world if we’re both working in the software industry in NSW. You could know me in real life and be fooled into thinking I’m a nice guy! As far as your questions in #147 go, I’m not sure. One obvious problem would be the uncertainty in aerosol and volcanic forcing. I also understand there’s uncertainty in the solar effects too – especially prior to the satellite era. I suspect it’s not quite as easy as you’re suggesting.

    Comment by Alex Harvey — 5 Feb 2012 @ 10:06 AM

  152. AH,

    The energy balance in the stratosphere is, to a first approximation, between absorption of solar UV by ozone, and emission of thermal IR by carbon dioxide. When CO2 increases, the troposphere warms, but the stratosphere cools. There is very little thermal IR (λ > 4 μ) which makes it up from the troposphere to the stratosphere, and almost none coming from the sun. The CO2 is heated by collision with the molecules surrounding it according to the laws of statistical mechanics. With the heating from solar UV steady and the level of CO2 increasing, the stratosphere cools down.

    But you would see this only in global warming caused by CO2 in particular.

    Comment by Barton Paul Levenson — 5 Feb 2012 @ 6:17 PM

  153. Apologies for the typo.

    No worries. Easily done.

    Yep, small world :-)

    I suspect it’s not quite as easy as you’re suggesting.

    It may be easier than you think, given that we don’t need really low uncertainty to get useful results. Obviously it gets harder if one demands “give me really low uncertainty, or death don’t bother!”

    Comment by Lotharsson — 5 Feb 2012 @ 6:39 PM

  154. > energy balance of the stratosphere … first approximation

    I highly recommend starting here:
    http://www.realclimate.org/index.php/archives/2004/12/why-does-the-stratosphere-cool-when-the-troposphere-warms/

    and reading several of the various attempts to get a clear first approximation in English over the following years that would be
    “… as simple as possible, but not simpler …”

    Sometimes it takes multiple efforts by several people to get it simple enough.

    Comment by Hank Roberts — 5 Feb 2012 @ 7:45 PM

  155. See also:
    http://scienceblogs.com/stoat/2011/09/why_does_the_stratosphere_cool.php

    Aside — in one of the intervening explanation pages, here
    http://www.realclimate.org/index.php/archives/2006/11/the-sky-is-falling/
    Gavin points to a 2006 article at
    http://www.atmosphere.mpg.de/enid/20c.html
    which says

    “…. our understanding of stratospheric cooling is not complete and further research has to be done. We do, however, already know that observed and predicted cooling in the stratosphere makes the formation of an Arctic ozone hole more likely.”

    And lo, we’ve had that happen in the last couple of years. Another prediction from radiation physics (and stratospheric chemistry) confirmed.
    http://www.theozonehole.com/nasaarctic.htm

    Damn!

    Comment by Hank Roberts — 5 Feb 2012 @ 7:53 PM

  156. Alex Harvey, I suggest the following reference:
    http://agwobserver.wordpress.com/2009/11/05/papers-on-climate-sensitivity-estimates/

    Look at the papers and evidence in their entirety–in particular, look at the progressively tightening bounds on sensitivity in recent years (Lindzen and Choi being an outlier–but then, Lindzen has made it clear he is no longer interested in science). This trend is easier to see here:

    http://bartonpaullevenson.com/ClimateSensitivity.html

    Comment by Ray Ladbury — 5 Feb 2012 @ 8:25 PM

  157. > Gabi Hegerl et al who have a comment on the paper (Hegerl et al.))

    Google Docs has that:
    https://docs.google.com/viewer?a=v&q=cache:1hrRFmV5vYMJ:journals.ametsoc.org/doi/abs/10.1175/BAMS-D-11-00191.1+http://dx.doi.org/10.1175/BAMS-D-11-00191.1&hl=en&gl=us&pid=bl&srcid=ADGEESg0vmq8uC77Vy5K4H09u2zY9AboZj1zc9iRhDI-YTw-xN296zIEINm50fDsEHcdQbHRYY73JHXOu6QipU65YcMLhy38qr2FuPF3g8WhutMEayh7srNgKQ37iMFltZI8O_IyL4Ri&sig=AHIEtbTC7mRoSl3oAnWWsUxFndl2UcHmNQ

    Comment by Hank Roberts — 6 Feb 2012 @ 4:50 AM

  158. John P. Reisman, 139
    “5. stratospheric cooling = put on a jacket and you trap more heat by radiating it back to your body, thus not allowing it to escape, thus cooling above your jacket (less heat escaping)…”

    And Brian Dodge,149, adding:
    “Adding energy from a heating pad [it’s the sun, it’s natural variability] can make you just as warm as putting on a jacket, but it will warm above you, the opposite sign of the effect of a jacket.”

    The jacket you are talking about is mostly in the troposphere and is mostly made of water vapour.
    As I understand from Gavin’s response to my 108, the stratospheric cooling is due to GHGs in the stratosphere itself, NOT to the tropospheric jacket.
    So I am not sure about your “jacket” analogy. Could you clarify?

    [Response: Science by analogy is an imprecise art. The ‘jacket’ works well for the troposphere, but not so much for the stratosphere. Whether the stratosphere would cool if only tropospheric CO2 were increased depends on the ratio of the energy flux absorbed at the CO2 lines to the total IR absorbed everywhere else and the distribution of anomalous upwelling IR. It is not a trivial calculation (though presumably the answer is known). Similarly, just changing stratospheric gases has an effect that also depends on the details of the radiative transfer (though, again, we know the answer). The point being that these things are not so obvious that they are amenable to argument by (imperfect) analogy. – gavin]

    Comment by Romain — 12 Feb 2012 @ 8:32 AM

  159. Ray Ladbury, #156:

    Thanks for the references and links. I do intend to read as many of the important papers that estimate climate sensitivity as I can. It will take me some time of course.

    I wanted to say something about Barton Paul Levenson’s graph of historical climate sensitivity estimates. I agree that it is interesting. In fact, I would love to see it extended to include all published estimates of climate sensitivity rather than a selection. (I know of at least a few that don’t appear there.)

    However, I don’t see the convergence myself, and if Roe and Baker (2007) are correct (that a very fat probability distribution for future climate change is an “inevitable and general consequence of the nature of the climate system”), it could be that any convergence that does occur might not be occurring for the right reasons.

    Indeed, what I find most interesting about BPL’s graph is the shift that occurs (well, appears to occur) from lower to higher climate sensitivity estimates right after the Charney Report was published in 1979.

    Is it possible that this graph is telling us something about ‘confirmation bias’ in some estimates of climate sensitivity?

    Comment by Alex Harvey — 12 Feb 2012 @ 10:22 AM

  160. Is the radiative cooling of the upper troposphere/lower stratosphere responsible for the downward flow of the Hadley Cell at 30 degrees N and S? If the planet had a dry nitrogen atmosphere, would air warmed by conduction from the surface convect to the stratosphere at the equator, then spread all the way to the poles, cooling slowly by conduction, and eventually sinking? so that the circulation in a dry, GHG free atmosphere would be two giant equator to pole Hadley Cells?

    Comment by Brian Dodge — 13 Feb 2012 @ 5:46 PM

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