Our JGR Paper on Feedbacks is Published

August 27th, 2010 by Roy W. Spencer, Ph. D.

After years of re-submissions and re-writes — always to accommodate a single hostile reviewer — our latest paper on feedbacks has finally been published by Journal of Geophysical Research (JGR).

Entitled “On the Diagnosis of Feedback in the Presence of Unknown Radiative Forcing“, this paper puts meat on the central claim of my most recent book: that climate researchers have mixed up cause and effect when observing cloud and temperature changes. As a result, the climate system has given the illusion of positive cloud feedback.

Positive cloud feedback amplifies global warming in all the climate models now used by the IPCC to forecast global warming. But if cloud feedback is sufficiently negative, then manmade global warming becomes a non-issue.

While the paper does not actually use the words “cause” or “effect”, this accurately describes the basic issue, and is how I talk about the issue in the book. I wrote the book because I found that non-specialists understood cause-versus-effect better than the climate experts did!

This paper supersedes our previous Journal of Climate paper, entitled “Potential Biases in Feedback Diagnosis from Observational Data: A Simple Model Demonstration“, which I now believe did not adequately demonstrate the existence of a problem in diagnosing feedbacks in the climate system.

The new article shows much more evidence to support the case: from satellite data, a simple climate model, and from the IPCC AR4 climate models themselves.


Back to the Basics

Interestingly, in order to convince the reviewers of what I was claiming, I had to go back to the very basics of forcing versus feedback to illustrate the mistakes researchers have perpetuated when trying to describe how one can supposedly measure feedbacks in observational data.

Researchers traditionally invoke the hypothetical case of an instantaneous doubling of the CO2 concentration of the atmosphere (2XCO2). That doubling then causes warming, and the warming then causes radiative feedback which acts to either reducing the warming (negative feedback) or amplify the warming (positive feedback). With this hypothetical, idealized 2XCO2 case you can compare the time histories of the resulting warming to the resulting changes in the Earth’s radiative budget, and you can indeed extract an accurate estimate of the feedback.

The trouble is that this hypothetical case has nothing to do with the real world, and can totally mislead us when trying to diagnose feedbacks in the real climate system. This is the first thing we demonstrate in the new paper. In the real world, there are always changes in cloud cover (albedo) occurring, which is a forcing. And that “internal radiative forcing” (our term) is what gives the illusion of positive feedback. In fact, feedback in response to internal radiative forcing cannot even be measured. It is drowned out by the forcing itself.

Feedback in the Real World

As we show in the new paper, the only clear signal of feedback we ever find in the global average satellite data is strongly negative, around 6 Watts per sq. meter per degree C. If this was the feedback operating on the long-term warming from increasing CO2, it would result in only 0.6 deg. C of warming from 2XCO2. (Since we have already experienced this level of warming, it raises the issue of whether some portion — maybe even a majority — of past warming is from natural, rather than anthropogenic, causes.)

Unfortunately, there is no way I have found to demonstrate that this strongly negative feedback is actually occurring on the long time scales involved in anthropogenic global warming. At this point, I think that belief in the high climate sensitivity (positive feedbacks) in the current crop of climate models is a matter of faith, not unbiased science. The models are infinitely adjustable, and modelers stop adjusting when they get model behavior that reinforces their pre-conceived notions.

They aren’t necessarily wrong — just not very thorough in terms of exploring alternative hypotheses. Or maybe they have explored those, and just don’t want to show the rest of the world the results.

Our next paper will do a direct apples-to-apples comparison between the satellite-based feedbacks and the IPCC model-diagnosed feedbacks from year-to-year climate variability. Preliminary indications are that the satellite results are outside the envelope of all the IPCC models.

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79 Responses to “Our JGR Paper on Feedbacks is Published”

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  1. Philip says:

    Thank you for putting your work in the public domain in this way, it is very much appreciated.

  2. Dominic says:

    I wholeheartedly second that.

    Dominic

  3. BCC says:

    I don’t seem to remember this site allowing comments- good luck with moderating!

    I appreciate your work and thank you for making your paper easy for us unwashed non-academics to get.

    I also think that until we all agree that the probability of the positive feedback model being wrong is very small, the prudent course of action is to avoid 3x CO2 (or wherever the BaU cases take us). So, keep at it.

    This is not your domain, but even if you knock off the positive feedback model, someone else will have to knock off the hypothesis that rapidly perturbing the ocean’s carbon chemistry (I won’t call it ocean acidification – oops) is also problematic.

    • Anonymous says:

      There is no end to the hypotheses that can be thrown by the purportedly “washed” at the unwashed to scare them, while a well established just-give-me-a-hypothesis..-ANY-hypothesis industry stands by ready to profit from the fear. In a better world, people of all hygenes will begin to stand up, say “So what?!” and not dignify all the hype until not only is there very solid objective evidence that there truly is a problem, but that the solution will definitely make us better off before all this time and money and freedom is spent on the doomsday scenario du jour.

      Considering this “problematic” is the problem.

    • Anonymous says:

      BCC
      Please, get your science right. Oceans? Acidic? Go away.

      • BCC says:

        Anonoymous #2,

        Here’s the science:

        H20 + CO2 H2CO3* HCO2- + H+

        Looks like an acid to me. And yes, I know that the pH of ocean waters is > 7. I’ll use the term ocean debasification if you prefer.

        And yes, I know the ocean is well-buffered on looooong time scales. But not on decadal timescales, which are the ones we’re operating on.

        It’s an interesting experiment.

        Anonymous #1- I know skeptics like to pretend that AGW fits into the “just-give-me-a-hypothesis..-ANY-hypothesis” bucket, but it doesn’t. It has over 100 years of scientific study (e.g. Arrhenius, 1896). Current estimates of climate sensitivity to 2x CO2 have multiple lines of evidence. At present, the burden is on scientists like Dr. Spencer to demonstrate otherwise. May the best science win. In the meantime, I’d prefer our society to be risk-averse.

        • BCC says:

          And thus the dangers of no “preview” mode- my &lt and &gt signs got nailed.

          I’ll use dashes in lieu of arrows:

          H20 + CO2 — H2CO3* — HCO2- + H+

          • Dominic says:

            @ BCC

            You state:

            ‘Looks like an acid to me. And yes, I know that the pH of ocean waters is > 7. I’ll use the term ocean debasification if you prefer.

            And yes, I know the ocean is well-buffered on looooong time scales. But not on decadal timescales, which are the ones we’re operating on.

            It’s an interesting experiment.’

            The pH of seawater varies greatly depending on where and when it is measured, but it tends to average around 8.07 or higher. Not ‘> 7′. That is misleading because the pH scale is logarithmic and we are a very long way away from ‘>7′. Aren’t we, BCC?

            So, yes please do stick to terms like ‘more basic’ rather than the entirely incorrect alarmism of ‘acidification’. Your credibility in serious circles will not suffer.

            Your second point seems confused, if not intentionally misleading. Decadal timescales are a component of century, millennial and longer timescales. Where’s the disconnect?

            Dominic

  4. JAE says:

    Increased warming would cause increased convection, also, no? Is this also a negative feedback?

    • It depends upon whether the increased convection leads to an increase or decrease in the radiative imbalance at the top of the atmosphere. “Convection” is a general term for a combination of a wide variety of atmospheric processes involved in the transport of heat from the surface upward. The answer might be that changes in convection will impact a wide variety of feedbacks: mostly cloud, water vapor, and lapse rate feedbacks.

  5. Eric Anderson says:

    Thanks, Dr. Spencer. Very interesting work and congratulations on the publication! This appears to be an exceedingly critical point of study, as it goes to the very heart of the models and modeling assumptiions. Keep up the great work and the openness!

    (P.S. Minor typo: I don’t know if you go back and edit posts once they are up, but if so, in the penultimate paragraph: “through” s/b “thorough”.)

  6. Freddie Stoller says:

    Thanks a lot Mr. Spencer,
    I appreciate your work very much. Your book is super to rea for a layman. Regards from the colder than “normal” Swiss mountains, Freddie

  7. Stephen Richards says:

    Dr Roy

    Thanks for your brave (yes brave) efforts in providing the science and the intelligence in this horrific debate.

  8. James Davidson says:

    What no one has mentioned is that computer climate modelling is doomed to failure. One of the first people to try computer climate modelling was Edward Lorenz. He found that tiny changes in the initial conditions, _ changes in the fourth, fifth and sixth places after the decimal point, led to huge differences in the outcome. Since initial conditions can never be measured to that degree of accuracy, he concluded that computer climate modelling was not possible in principle. His paper on this formed the starting point for the mathematical theory of Deterministic Chaos, which has been cited, along with general relativity and quantum theory as being one of the three great advances in human thought of the 20th century. One of the scientists writing the Third assessment report for the IPCC wrote: ” In climate research and modelling, we should realise that we are dealing with a coupled, non-linear chaotic system, and therefore that long range forecasting of future climate states is not possible.”
    (3AR Sec 14.2.2.2.) The UK Met Office has realised this and has stopped giving seasonal forecasts after last years debacle . It promised a ” barbecue summer” ( it turned out cold and wet,) followed by a ” mild winter,” ( record low temperatures and snowfall.) It now issues forecasts for one month in advance, updated weekly. As Freeman Dyson has said: ” Computer models must constantly be checked against reality, and if you can’t do that, then don’t trust the model.”

    • James, the climate modeling crowd are all aware of Lorenz and his contribution. What they will tell you is that their climate forecasts are not based upon a change in INITIAL values, but a change in BOUNDARY CONDITIONS. Doubling the CO2 content of the atmosphere changes the “rules” by which the atmosphere operates. How the system responds in terms of feedbacks (sorry, Christopher) is the question.

      • Anonymous says:

        Reply from Christopher Game to Dr Spencer’s post of 2010 Aug 30 at 7:04 AM, which was a reply to James Davidson’s post of Aug 28 at 9:42 AM.

        Hey! hey! that’s not right, you can’t fairly accuse me of opposing the idea of feedback; it’s its flawed use that I oppose. I am a keen user of the idea of feedback properly practiced. Christopher

  9. Todd A says:

    Dr. Spencer,

    I teach environmental science at a community college in Pennsylvania. I really have a hard time finding educational materials that do a good job of de-bunking the IPCC reports that seem to bias our textbooks.

    Are you aware of educational resources (other than your new book) that could be used to have a more balanced discussion on the global warming debate?

    Thank you and keep up the good fight!

    ToddA

    • Good for you, Todd. Unfortunately, I don’t know of such a textbook. Maybe others here do.

    • Anonymous says:

      Check out Andrew Montford’s “The Hockey Stick Illusion.” It traces the history of the attempt to show that the 20th century warming was exceptional. It is extremely detailed, with few polemics. Between the feedback issue and the hockey stick, you have the “attribution” issue pretty well covered.

  10. Gene Nemetz says:

    “After years of re-submissions and re-writes — always to accommodate a single hostile reviewer…”

    The hostile reviewer probably didn’t know it, or intend it, but he made you a better scientist. :-)

  11. David Davidovics says:

    I just found out about this over on WUWT and wanted to post my thanks and congratulations here. Dr. Spencer, your work and dedication is an example to many despite the hostile reception you are facing.

    Also a thanks to Todd A for daring to even think about teaching the other side of the issue. The world needs more thinkers and less political activists.

    Days like this give me hope for the future.

  12. Ric Werme says:

    Leif Svalgaard published at http://wattsupwiththat.com/2010/05/29/leif-svalgaard-on-the-experience-of-peer-review/ his experience with getting a paper of his through the peer review process. It sounds like this paper’s journey would be just as interesting, though it might drag on in places :-) .

    Can you publish your experiences with the review process with this paper?

  13. Jeff Id says:

    Dr. Spencer,

    Thanks for the guts to keep pushing back against the assumptions of positive feedback. I think your paper was more than generous to separate short and long term feedback so clearly that it gave space for the long term positive feedback to still exist.

    I can only imagine the review comments.

    I don’t know if you can comment, but did you see any evidence that long term feedback was different than the short term from the satellite data. Realizing of course that the data is too noisy for a firm determination.

    • Toward the end of the paper, we show evidence from 3 or 4 climate models that had “feedback stripes” that the slope of those stripes (which were in the IR component only…not the reflected solar part) were about the same as the known long-term feedbacks operating in those models. That is the only evidence I have found, so far.

  14. RayG says:

    I echo the “thank you’s” from most other commenters and also echo a request on WUWT. Please post the reviewers’ comments.

    Tks,

    RayG

  15. MarkkuP says:

    Hi

    this approach is very welcome. In basic physics radiation blocking substance between Earth and space reduces energy flow. As clouds block visible radiation, it is clear that incoming energy is smaller. This is easily observed any day, as clouds blocking sun decrease temperature with some 5-10 C.

    What is strange in the positive feedback hypothesis is that as clouds have excess energy evaporated either from sea or earth, this excess energy could then establish a positive feedback loop. From my opinion clouds are a way to radiate above average energy to space with additional area-altitude aids. Positive feedback inturn could then lead to additional clouds and thus excessive heating loop. Scenario clearly seems to be a conflicting one, as temperature elevation could not be limited. Only so high temperatures that would evaporate clouds would then stop this scenario.

    In this logically correct?

    Markku

    • In terms of a direct radiative influence, low clouds have a net cooling effect (solar reflection greater than reduction in outgoing IR), where as high, thin cirroform clouds have a net warming effect (reduction in outgoing IR is greater than their solar reflection).

      I say “DIRECT radiative influence” because the processes that caused the clouds to form in the first place might themselves involve feedbacks which counteract the cloud feedbacks. These indirect effects greatly complicate things, and people seldom talk about them. It’s a nuance I have always wondered about.

  16. I’m still working through your paper – very interesting, by the way – and I was interested in how you calculated the “zero feedback” condition for OLR.

    Ramanathan & Inamdar in “Frontiers of Climate Modeling” comment that the “zero feedback” condition for OLR is also 3.3 W/m^2.K.

    In his case it is with reference to his (Ramanathan’s) very involved 1981 paper, “Role of Ocean-Atmosphere Interactions in the CO2 Climate Problem”.

    In your paper you say “..amounting to about 3.3 W/m^2.K at the average effective radiating temperature of the earth, 255K.”

    Because d(OLR)/dTeff = 3.7 – 3.8 W/m^2.K at this radiating temperature I was interested in your derivation of the “no feedback” case of 3.3 W/m^2.K – can you comment on this?

    I am currently in discussion about this subject on: http://scienceofdoom.com/2010/08/29/clouds-and-water-vapor-part-one-responses/

    -and have cited your paper.

    • yes, you are right if one is talking about the top-of-atmosphere…and we were not clear about this. The 3.2 number is that change at the tropopause, which is where some people like to reference everything since they believe all of the feedbacks will be below that level, in the troposphere. I don’t dabble in these details…sorry for the confusion.
      -Roy

  17. Juho says:

    Congratulations Dr. Spencer for publication!

    What do you think about the latest McIntyre&McKitrick&Hughes paper, about tropical trends? Doesnt their findings support your results and refute any positive feedbacks at least in 30N-30S?

  18. Mike says:

    Congratulations, Dr. Spencer, and well done for persevering to get the paper published.

    Thank you for doing honest climate science.

    • Miket says:

      My feelings exactly. Keeping a balanced approach to climate science in the existing environment, as you appear to do, must be very difficult, and I take my hat(er baseball cap) off to you Dr Spencer.

  19. Christopher Game says:

    Christopher Game replying to Dr Spencer’s article on his new JGR paper.

    Dear Dr Spencer,

    Congratulations on your navigating the north-west passage bewteen the bergs of reviewing ice. Happy sailing in the ocean you have reached.

    You write: “…the feedback operating on the long-term warming from increasing CO2… … Unfortunately, there is no way I have found to demonstrate that this strongly negative feedback is actually occurring on the long time scales involved in anthropogenic global warming.”

    Please do up your seat-belt and put on your safety helmet and eye-protection spectacles and hearing protection before reading the next sentence or two.

    It will not be possible to demonstrate feedback to something that did not occur. Feedback relies on the actual effects of a driver to actualize the potential for feedback.

    There has been no anthropogenic global warming (AGW), and so feedback to it cannot have occurred.

    Now to explain these shocking statements.

    AGW means warming of the climate due to climatic-time scale increase in CO2 levels due to human-induced CO2 emissions. Such an increase is widely supposed to work by increasing the global average Planck-weighted greenhouse-gas optical thickness of the earth’s atmosphere, CO2 being one of the greenhouse gases that is factored into the calculation of that quantity. No other mechanism is proposed in the usual doctrine.

    This means that for the occurrence of AGW, it is necessary that there should have occurred an increase in global average Planck-weighted greenhouse-gas optical thickness.

    We now have direct evidence about this. Over the past 61 years, when there was substantial increase in CO2 levels, there was no increase in global average Planck-weighted greenhouse-gas optical thickness of the earth’s atmosphere. The hypothesized mechanism of AGW did not operate. No climate theory is needed to know this: it is simply an empirically observed fact.

    What was the mechanism that prevented the AGW mechanism from operating?

    Surprisingly it was simply a direct temperature effect that can be understood in terms of the idea of the atmospheric window. Though the increase of CO2 levels must have caused a virtual direct no-feedback increase in global average Planck-weighted greenhouse-gas optical thickness, as supposed by the AGW doctrine, there was a countervailing virtual direct no-feedback effect of temperature that nullified the CO2 virtual effect. This effect of temperature had two mechanisms: the spectrum of the thermal radiation from the land-sea body moved into better alignment with the ‘effective’ spectrum of the atmospheric window; and the actual effective emissivity=absorptivity of the greenhouse gases of the atmosphere was directly reduced by the increase of temperature.

    It has been proposed that the steady value of the global average Planck-weighted greenhouse-gas optical thickness was inaccurately observed because of inaccuracy of the upper tropospheric water vapour radiosonde data over the past 61 years, but this is not so. The temperature effect did the job: when the optical thickness was calculated with, instead of the 61 actual water vapour sounding profiles, an artificial constant water vapour sounding profile, there was still a full compensation for the virtual CO2 effect by the virtual temperature effect; the result: no actual direct no-feedback effect of CO2. The water vapour changes had nothing significant to do with the compensation. So suspected inaccuracies in the water vapour measurement did not impinge on the fact of temperature-mediated compensation that kept the global average Planck-weighted greenhouse-gas optical thickness steady.

    This of course does not impugn your admirable investigation of the actual cause of the warming, which as I understand it, was mediated by a decrease of cloud formation over the climatic time scale, as demonstrated by your admirable work. So far as I know, the cause and mechanism of the decrease of cloud formation is not definitely known, though some reasonable hypotheses have been proposed. Perhaps the cause of the recent warming may be reversed soon and give us a couple of decades of troublesome cooling?

    All I am saying here is that, over the past 61 years, 1948-2008, there was no actual CO2-induced warming and so one cannot expect to find feedback to it. Thus it is fortunate that you “have not found a way to demonstrate” it, since it did not happen.

    I am of course neither denying nor asserting the occurrence of feedbacks to the actual changes that did occur over the 61 years; such is beyond my knowledge.

    Yours sincerely,

    Christopher Game

    • Christopher, to arrive at your bold conclusions, you have made 2 bold assumptions that most others will disagree with:
      (1) that there has been no warming, and
      (2) that the early radiosonde water vapor measurements can be believed.

      The people who have been involved in the development and use of these early (and later) humidity sensors will tell you to not trust long-term trends from them.

      • Anonymous says:

        Christopher Game replying to Dr Spencer’s post of 2010 Aug 30 at 7:23 Am in reply to Christopher Game’s post of Aug 29 at 8:00AM.

        Dear Dr Spencer,

        Thank you for your reply.

        You write: “Christopher, to arrive at your bold conclusions, you have made 2 bold assumptions that most others will disagree with:
        (1) that there has been no warming, and
        (2) that the early radiosonde water vapor measurements can be believed.

        The people who have been involved in the development and use of these early (and later) humidity sensors will tell you to not trust long-term trends from them.”

        No, no!!

        I do not assume that there has been no warming. I explicitly recognise that there has been warming. That is an essential part of my reasoning. What I assert is that warming that did occur was not caused by CO2 increases. I think that the warming was caused by factors other than CO2 increases; you have evidence that part of the mechanism was decrease in cloud formation, which I assert is not due to CO2 increase.

        I explicitly do not assume that the early water vapour measurements can be believed. I explicitly show that they are hardly relevant to the compensation that maintained the stationary value of the global average Planck-weighted greenhouse-gas optical thickness. The compensation was a direct result of the temperature increases that you say I denied the existence of.

        I think if you read my post again you will agree that I did not make either of the assumptions that you list above.

        Yours sincerely,

        Christopher

    • Anonymous says:

      Christopher Game adding to his own post of 2010 Aug 29 at 8:00 AM.

      Christopher says to all readers:

      One of my friends just told me that I am a fault-finding fuddy-duddy, fussing futilely over the “forcing-and-feedback” formalism, and that I am making a muddy mess in Dr Spencer’s fine blog.

      I would just like to make it clear that I am attacking the establishment’s formalism by perhaps unjustly but conveniently for me using or perhaps misusing Drs Spencer and Braswell’s valiant and most admirable work as a carrier for my personal views.

      As to their work, my post just above says: “This of course does not impugn your admirable investigation of the actual cause of the warming, which as I understand it, was mediated by a decrease of cloud formation over the climatic time scale, as demonstrated by your admirable work.”

      • Christopher, despite that fact that you frustrate me even more than my wife does at times, I still value your input.

        Oh, I value my wife’s input, too (just in case you are reading this, Dear). :)

  20. Buzz Belleville says:

    OK, I’ve read both the book and the IPCC reports (all of them). I’ll wade thru the actual article Dr. Spencer has been trying to get published within the next few days. But here are my two biggest ignorances (is that a word?).

    (1) There seems to be this repeated mantra that the 18 models cited in the IPCC 4AR all (incorrectly) show a positive feedback from clouds … and I just don’t think that’s true. The various models showed a huge spread with respect to the effect of clouds. Both the narrative to the Group report and the Synthesis Report were explicit in the lack of understanding re the effect of clouds. I thought most of the cited models gathered around the zero point … either no or minimal effect from clouds. The positive feedabcks from water vapors were in all of them (with perhaps a warming-viased error in assuming stable relative humidity … time will tell). But I thought most netted clouds out to close to zero impact. Could someone — Dr Spencer or another on this board — please correct my understanding … which (and how many) models actually showed a strong warming effect from presumed clouds. I really want to understand this and why I’ve gotten it wrong to date.
    (2) Is there really any empirical evidence to support this theory? That is, do we have data showing that there have been an increased level of warming-causing cloud cover globally? My understanding was that we’re only some 6-8 years into collecting data on global cloud cover (that NASACloud satellite, or whatever it is called). And, for whatever reason, NASA doesn’t seem to have updated its page on results from that satellite for a couple years. Assume that I understand Dr. Spencer’s theory (I’m getting there, but still have work to do), is there any actual empirical data to show that recent warming even correlates (put aside causation) with increased global cloud cover.

    Thank you to anyone who can help fill in the gaps of my knowledge.

    • Thomas says:

      Buzz, check fig 8.14 in the latest IPCC-report. For all but one model feedback from clouds is positive. Do look at the rightmost column in the diagram, though. The total uncertainty in the feedback is less than the sum of the individual feedback, since the different feedbacks aren’t independent. Models that has one feedback high tends to have others (esp. LR) lower.

      • Anonymous says:

        Thanks Thomas … I’ll check it out.
        Buzz

      • Anonymous says:

        Thomas — Figure 8.14 is simply a depiction of feedback variations for only three of the models discussed inthe IPCC report. It is not an attempt to depict results from all of the 15 models used, and its purpose is to attempt to explain the spread in models’ climate sensitivity estimates (not to explain the predicted feedback effect of clouds).

        Figure 8.15 (and section 8.6.3.2) is an attempt to collect all of the models’ cloud feedback results. And, as I initially believed, it explains that the “models exhibit a large range of global cloud feedbacks, with roughly half of the climate models predicting a more negative [climate radiative forcing], and half predicting the opposite.” The figure (8.15) shows that 7 of the 15 models included in the IPCC report show a negative forcing from clouds, and 8 of them show a net positive forcing. Thus, it just seems wrong to assert, as Dr. Spencer does, that “positive cloud feedback amplifies global warming in all of the climate models now being used by the IPCC to forecast global warming.” Half of the models actually show clouds to have a negative feedback effect! What am I missing?

        Buzz Belleville

  21. Invariant says:

    I just wonder. Imagine that feedback most of the time is mainly positive. This would mean that our climate is inherently unstable and that any perturbation would lead to a diverging climate right? Honestly speaking, is this the hypothesis of the “consensus” Dr. Spencer? How is it possible to explain the relative minor temperature fluctuations since the end of the last ice age with this hypothesis? I find it highly unlikely that feedback is positive, in particular all the time and for all climate states! Then a butterfly would have ended our civilization a long time ago. Please explain how the “consensus” thinks that feedback can be positive without leading to catastrophe Dr. Spencer.

    • Invariant, you need to pay attention. You assume you know what people have claimed, but you don’t know. “Feedback” in the sense you are talking about is indeed negative in all of the climate models…even those that produce a lot of global warming. In climate, positive feedback means something different than it does in other disciplines….it, in a sense, has a different zero-baseline.

      • Invariant says:

        Thanks for pointing this out Dr. Spencer. At Wikipedia I found this definition of feedback:

        “The main positive feedback in global warming is the tendency of warming to increase the amount of water vapor in the atmosphere, a significant greenhouse gas. The main negative feedback is radiative cooling, which increases as the fourth power of temperature; the amount of heat radiated from the Earth into space increases with the temperature of Earth’s surface and atmosphere.”

        My next question is then whether this definition of feedback is at all useful? I would imagine that it is the overall feedback that is important, one cannot investigate each mechanism separately – in a non-linear system all Liapunov exponents may contribute and their magnitude may not be independent.

        • yes, it is an extreme simplification. If you read Christopher Game’s posts here, he also talks about whether it is a useful metric. There have been a couple of papers that have essentially admitted as much. The modelers DO tend to view the system in too simplistic of terms. They know it is complex, but I don’t think they are willing to admit it that it can’t be usefully approximated in simple terms. I don’t really know….maybe, maybe not. I just know that the situation is not as simple as the IPCC makes it out to be.

          • Invariant says:

            Thanks Dr. Spencer. Then I understand the origin of my misunderstanding. The concept “feedback” is being used in the AGW gospel to convince policy makers and journalists that increased CO2 is very dangerous. The climate modellers know this is a gross simplifaction, but they do not mind because the cash certainly is raining in…

          • Anonymous says:

            Christopher Game replying to Dr Spencer’s post of 2010 Aug 30 at 10:58 AM.

            Dear Dr Spencer,

            You write: “The modelers DO tend to view the system in too simplistic of terms.”

            My criticism of the IPCC formalism is not directed at its simplicity, but at the flaws in its formal structure. I do not think that it is necessarily impossible to provide a very simple theory by which to analyse the possible effects of CO2 emissions. What I am saying is that the desired theory should be a tailor-made physical theory, not a one-size-fits-all procrustean formalism. I have proposed that as the flawed IPCC formalism stands it demands complications in its own terms; but my remedy is, not to go ahead and complicate the flawed formalism, but to search for a new and neater physical theory.

            Yours sincerely,

            Christopher Game

        • Anonymous says:

          Christopher Game commenting on the post of Invariant of 2010 Aug 30 at 10:05 AM.

          Dear Invariant,

          You write: “At Wikipedia I found this definition of feedback:

          “The main positive feedback in global warming is the tendency of warming to increase the amount of water vapor in the atmosphere, a significant greenhouse gas. The main negative feedback is radiative cooling, which increases as the fourth power of temperature; the amount of heat radiated from the Earth into space increases with the temperature of Earth’s surface and atmosphere.”

          My next question is then whether this definition of feedback is at all useful?”

          Christopher’s comment:

          Invariant, this is not a definition. It is a judgment about what are the main feedbacks. It is a summary statement of a theoretical dogma. A definition is theoretically neutral, just giving the meaning of words; not like the above statement that you quote.

          In more detail, the above that you quote is a statement of opinion from the Wikipedia. It does not accurately represent the IPCC formalism which does not count radiative cooling as a feedback; the IPCC formalism counts radiative cooling as what it calls the “Planck response”, and it puts that response in the place of the ‘feedforward’ or virtual active part of the feedback loop, to speak in terms of the Bode theory.

          Dear Invariant, the Wikipedia is often useful if read very cautiously indeed, but you should know that many of the more controversial articles are written by non-experts on the principle that the editor with the most headstrong and arrogant approach dominates, and no matter how ignorant he is, he will likely push out more reasonable and better informed editors, who do not have time to waste arguing with him. In general, the Wikipedia is a monument to the power of the forces of ignorance and darkness, as well as a useful aid at times.

          Yours sincerely,

          Christopher Game

          • Invariant says:

            Thanks. I am familiar with Dr. William Connolley and Wikipedia. Still, I am really trying to figure out what is going on inside the minds of the AGW people. Then reading Wikipedia is useful. Possibly you should read:

            “On Fact and Fraud: Cautionary Tales from the Front Lines of Science”
            Dr. David Goodstein.

            http://eands.caltech.edu/articles/LXXIII3/2010_Summer_BookReview_FactAndFraud.html

            Honestly speaking I do not think the AGW crowd is trying to fool us. Instead I think the problem is that they are fooling themselves – as David Goodstein points out: there are rather few examples in the history of science where scientists deliberate are cheating, cold fusion is a nice example of self-delusion.

          • yes, I agree that this, too, is happening. The way I have phrased it is that scientists have not been careful about investigating alternative hypotheses. As a result, they will virtually destroy the reputation of climate science.

          • Anonymous says:

            Christopher Game replying to Invariant’s post of 2010 Aug 30 at 1:34 PM.

            Dear Invariant,

            If you are so clued up on the vagaries of the Wikipedia, that would seem a reason why you should not have quoted it as you did.

            I am sorry you mentioned a particular name in your comment. That particular name was not in my mind when I wrote my comment.

            Yours sincerely,

            Christopher Game

  22. wayne says:

    Dr. Spencer, that has to be one of the easiest papers to read I have come across in year. I had no problem following it start to end. Great paper. Especially thanks for the few “in other words” when you went off into climate science special areas, that helped immensely without spending so much time trying to figure out what is being said that you never can finish the paper. Bravo.

    • Well, maybe you need to work in climate, Wayne. The experts cannot see past what they think I am saying, or past their assumption that everything that has been done up to now is correct (kinda a silly attitude to have in science, I think).

  23. Harp;d Pierce Jr says:

    Roy says:

    “Researchers traditionally invoke the hypothetical case of an instantaneous doubling of the CO2 concentration of the atmosphere (2XCO2).”

    What metric is used for CO2 in these climatle model calculations? If the metric is ppmv, then this metric is incorrect.

    After analysis, the concentration for CO2 in a sample of local air is reported for purified dry air (PDA) which does not occur in the earth’s atmosphere and is comprised of nitrogen, oxygen, the inert gases and CO2, often called the fixed gases. The composition of PDA (i.e., the relative amounts of the fixed gases) is fairly uniform through out the atmosphere and is idependent of location, pressure, temperature, and humidity except for local variations in particular with respect to CO2. This is the origin of the term “well-mixed atmospheric gases.”

    For PDA at STP (i.e., 273.15 K and 1 atm. pressure), there are presently about 390 ml, 17.4 millimoles, 766 mg, or 0.000766 kg of CO2 in 1 cubic meter. The density of PDA at STP is 1.29 kg per cubic meter.

    In real air there is no unifrom distributon of the masses of the consituents including water vapor and clouds in the atmosphere in space and time as is shown by daily weather maps of the various regions of the earth. High pressure cells have more mass of the gases than do low pressure cells, and thus there is no uniform distribution of CO2 in the atmosphere. Air containing water vapor is less dense than dry air and has less mass of fixed gases.

    Clouds are liquid water in the air, and the tiny droplets of water will contain the atmospheric gases, the amount of which will depend on local temperature and pressure. Since clouds move about they can transport CO2 in the liquid phase from location to location. Depending on local conditions, they can release into local air some on the gases or evaporate and release all the gases and water vapor. The clouds can also release rain drops which will carry the atmospheric gases to the earth’s surface.

    Given the above I have concluded that climate can not be modelled with any useful skill and accuracy. Also how do climate models take into account the variable R factor for the atmosphere?

    • Everyone knows that water vapor and clouds are not evenly distributed. But gases like O2, N2, and CO2 can be assumed to be well-mixed for the purposes of determining the net effect of CO2 on climate. This assumption is small compared to the other questionable assumptions that manmade global warming hinges upon.

      • Anonymous says:

        Roy says:

        “But gases like O2, N2, and CO2 can be assumed to be well-mixed for the purposes of determining the net effect of CO2 on climate.”

        That assumption is an absolute fatal flaw for all climate model calculations because the gases are not well-mixed with respect to mass in real air. For gases the mass per unit volume is determined primarily by local temperature, pressure, humidity and clouds, and there is no unifrom distribution of these in the atmosphere as shown by weather maps.

        Air flows from a high pressure cell to a low pressure and thus there is a horizontal gradient of mass. When the wind blows strongly over the ocean, an enormous mass of not only atmospheric gases but also water vapor flows inland which occurs when a hurricane makes land fall, for exzample.

        For climate model calculations involving greenhouse gases, the metric that should be used is either mass per unit volume or moles per unit volume.

  24. Harold Pierce Jr says:

    Here is a comment I just posted over at Tamino’s blog which did not see the light of day.

    E: The Positive Water Feedback Hypothesis

    At 14 deg C and 1 atm. pressure, 1 cu. meter of air has 12.1 g of water vapor for 100% humidity. If the temperature of the air is increased to 15 deg C, 1 cu. meter will now have 12.8 g of water vapor for 100% humidity , a small increase of only 0.7 g or 6.7% of water vapor. However, 100% humidity only occurs if it is raining or snowing or if there is dense fog. So how does the enormous amounts of surface water enter the atmosphere?

    The wind is the force that transports surface water into the atmosphere and is far more inportant than simple evaporation of water in still air. When wind blows over a body of water, the surface will cool but water will still be transported into the air, and due to their momentum the much heavier nitrogen and oxygen molecules and argon atoms just blast the lighter water molecules out the surface water into the air.

    Changes in air pressure are also more important than a slight increase in air temperature as is shown on an aneriod barometer. An air pressure drop of a few inches (ca 60 mm) of mercury will often cause rain or snow. If pressure increases, the air becomes dry. The heat of vaporization of liquid depends on external pressure.

    Clouds are liquid water in the air and depending on local temperature , pressure and humidity, they can readily release water vapor into the air or drop excess moisture as rain, snow or ice pellets to the earth’s surface.

    Given the above I have concluded that positive water feedback exists only in the imagination of the climate scientist.

  25. Buzz Belleville says:

    Now I’m thoroughly confused. This blog entry states that “positive cloud feedback amplifies global warming in all of the climate models now being used by the IPCC to forecast global warming.” But section section 8.6.3.2 (and Figure 8.15) of the 4th AR is explicit is stating (and showing) that the “models exhibit a large range of global cloud feedbacks, with roughly half of the climate models predicting a more negative [climate radiative forcing], and half predicting the opposite.” Seven of the 15 models used by IPCC predict that clouds will have a negative feedback effect.

    What am I missing?

  26. R. de Haan says:

    Thank you Sir because you have hit the nail on the head.

    If we simply would take all the extremes from the past 2000 years, cold as well as warm and call it “Climate Variation”, we could dump not only the IPCC but also Climate Change in the dumpster together with all the other propaganda based schemes and doctrines from the past century and save a heck of a lot of time and money in the process.

  27. Catrun J says:

    So do I understand this correctly? We as a planet are going
    to double the C02 in the atmosphere over the coming decades
    (you, Dr. Spencer seem insistent that we should not be deterred), and everything is going to be OK because it will just get cloudier (and maybe a tad warmer).

    So we should all just relax. Nothing to worry about here.

    • Oh, I predict there will be some change. I predict slightly warmer will be better, and that life on land and in the ocean will become more resilient and more abundant as a result of more CO2.

      Catrun, do you consider yourself an independent thinker? Do you know what unintended consequences are? Do you realize the huge increase in quality of life and longevity that fossil fuels have brought to humanity in the last 100 years? Do you realize there are no large-scale replacements for fossil fuels yet? Did you know that the mere fact that everyone needs energy means that private industry is always trying to find new ways, including alternative energy sources, to satisfy that need? Do you realize that when government decides where people should spend their money, that wealth is destroyed and people suffer?

      I don’t really care where the energy comes from. But I care that it is as affordable as possible.

      • Anonymous says:

        Unequivocably agreed. The dinosaurs, etc. gave us a wonderful gift of potential energy, which we can obtain economically, with minimal impact on the Earth compared to solar, wind, biofuels, etc. Funny, but when I started to try to educate myself about all this CO2 ppm stuff, I thought, even accepting a reasonable amount of warming, that 450ppm looked kind of optimum, what with the plants really liking the richer atmposphere and humans as a whole really liking the slightly warmer temperatures. And that more than 450 ppm wasn’t going to have much more effect anyway. Sounded like an amazing win-win to me. And the negative consequences? Sea level rise? I think we can handle a meter per century–we’ll have to because that’s what’s been happening for the past several centuries anyway. Increased hurricanes? Wrong! Droughts? Wrong! Ocean acidification? Oh please. Extinctions? C’mon–that’s happening all the time anyway. Decrease in ski resort revenue? Yeah, maybe, but I think somehow society can adjust to that. All the catastrophic prognostications just never passed the smell test with me.

        We’ll have to figure out how to produce energy without fossil fuels someday, but we can let the economics of finding/producing petro fuels take care of the transition to alternative fuel sources. Methinks we will stop increasing atmospheric CO2 levels far short of most modeled estimates.

  28. I would like to further elaborate on the statement above by Harold Pierce Jr: “the much heavier nitrogen and oxygen molecules and argon atoms just blast the lighter water molecules out the surface water into the air”. It is a common misconception that buoyancy applies to gases as it does to liquids, however that is not the case. If we take a helium filled balloon in a room, it would rise to the top, however a CO2 filled balloon would go to the bottom. However if we poke a hole in each balloon, the individual molecules spread out very evenly. And in the atmosphere outside, the distribution of all gas molecules with the exception of water vapor, is very consistent. If all heavier molecules would sink to the bottom, then we would never have very heavy chlorofluorocarbons in the stratosphere. Helium atoms do escape from our atmosphere. However it is not due to buoyancy. You could have a CO2 molecule and a helium atom in the same place high in the atmosphere at the same temperature. Being the same temperature means the translational kinetic energy is the same. Kinetic energy is calculated by the formula E = 1/2mv2. Since the helium atom is much lighter than the CO2 molecule, its velocity at the same temperature is much higher so it can reach escape velocity and thereby leave Earth. By contrast, Jupiter has a larger gravitational field and a lower temperature than Earth, so it can hold on to its hydrogen and helium.

  29. Harold Pierce Jr says:

    ATTN: Roy

    RE: Anonymous says: August 31, 2010 at 12:05 AM

    “Anonymous” should be “Harold Pierce Jr”

    I clicked on “Reply” after your comment on August 30, 2010 at 9:44 AM, and expected my name to appear above the comment. So how did “Anonymous” appear there instead?

    How does this “Reply” function work?

  30. Harold Pierce Jr says:

    Reply to Werner Brozek, August 30, 2010 at 7:54 PM

    We chemists routinely use a directed stream of dry nitrogen or argon to evaporate small of amounts of liquids from test tubes. Volatile solvents such ether, pentane, hexane acetone, ethyl acetate, etc evaporate quite quickly and water is no exception. The rate of evaporation of water and other liquids can be greatly increased by putting the test tube in bath of warm water and using a high flow rate of gas.

  31. harrywr2 says:

    Catrun J says:
    August 30, 2010 at 5:45 PM

    “So do I understand this correctly? We as a planet are going
    to double the C02 in the atmosphere over the coming decades”

    If you can find me 1,000 billion tons of coal that can be mined and delivered to Asia,Afica or Europe for less then $100 a ton you are correct . Of course, I and thousands of other greedy capitalist pigs will be more then happy to shower you with riches beyond your wildest imagination if you are successful in your quest.

    Unfortunately, the Europeans, Chinese and Indians have been on a similar quest and have so far failed.

  32. Christopher Game says:

    Christopher Game replying to the post of Anonymous of 2010 Sep 1 at 8:26 AM.

    Is “anonymous” really sure that the petroleum and coal fuels are fossils and not of deep interior or earth core geological origin, colonized by bacteria, as they find their way towards the surface? What does he think of the arguments of Thomas Gold in The Deep Hot Biosphere: The Myth of Fossil Fuels, Copernicus, Springer-Verlag, New York, 1999/2001, ISBN 0387952535?

  33. andrew99 says:

    Let a grand jury return true bills on all this!

    “Science”

  34. FollowFacts, Dixie says:

    BCC writes (August 27, 2010): “I also think that until we all agree that the probability of the positive feedback model being wrong is very small, the prudent course of action is to avoid 3x CO2 (or wherever the BaU cases take us).”

    On the contrary.

    Sunstein, Cass R. “Throwing precaution to the wind: Why the ‘safe’ choice can be dangerous.” Opinion. boston.com – The Boston Globe, July 13, 2008. http://www.boston.com/bostonglobe/ideas/articles/2008/07/13/throwing_precaution_to_the_wind

    Main point: “Yet the precautionary principle, for all its rhetorical appeal, is deeply incoherent. It is of course true that we should take precautions against some speculative dangers. But there are always risks on both sides of a decision; inaction can bring danger, but so can action. Precautions, in other words, themselves create risks – and hence the principle bans what it simultaneously requires.”

    “In the context of climate change, precautions are certainly a good idea. But what kinds of precautions? A high tax on carbon emissions would impose real risks – including increased hardship for people who can least afford it and very possibly increases in unemployment and hence poverty. A sensible climate change policy balances the costs and benefits of emissions reductions. If the policy includes costly (and hence risk-creating) precautions, it is because those precautions are justified by their benefits.

    “The nations of the world should take precautions, certainly. But they should not adopt the precautionary principle.”.

    Cass Sunstein is Obama’s regulatory czar; some other publications are:

    Sunstein, Cass R. Beyond The Precautionary Principle. Working Paper #38. Public Law and Legal Theory. University of Chicago, January 2003. http://www.law.uchicago.edu/files/files/38.crs_.precautionary.pl-lt.pdf
    ———. Laws of Fear: Beyond the Precautionary Principle. Cambridge, UK: Cambridge University Press, 2005.
    Sunstein, Cass R., and Eric A. Posner. “Global Warming and Social Justice.” Regulation (Spring 2008). http://www.cato.org/pubs/regulation/regv31n1/v31n1-3.pdf
    Sunstein, Cass R., and David Weisbach. Climate Change and Discounting the Future: A Guide for the Perplexed. Working Paper. Reg-Markets Center, AEI Center for Regulatory and Market Studies, August 2008. http://aei-brookings.org/admin/authorpdfs/redirect-safely.php?fname=../pdffiles/phpEK.pdf

  35. andrew99 says:

    Already been destroyed…I do not think anybody will trust “scientists” again (unles they are mathematicians, physicists & etc. rather than these jumped up geographers).

    The Senate of the United States
    The Australian Senate
    The Attorneys- General of Texas and Virginia

    (all directly elected by the people – the people have a say in all this?)

    all deny the basic propositions of the climate change enthusiasts.

    So let the grand juries start work…

  36. Fred Moolten says:

    Regarding your JGR paper, it seems to me that a number of questions arise as to interpretation of estimated negative feedbacks. These involve the accuracy of TOA measurements, and the possible failure of short term assessments to capture climate “memories” such as transfer of heat to the deep ocean that will not manifest itself over intervals shorter than decades. In addition, however, I would suggest an additional concern – the relevance of feedbacks from short term climate perturbations (including what you term internal forcings) to feedbacks generated long term by forcings imposed by changes in atmospheric components such as CO2.

    In the short term, climate variability is dominated by “internal” changes, including ENSO events as an example. Therefore, the feedbacks they engender will dominate the analysis, but is there reason to conclude they must necessarily be the same in magnitude and sign as the feedbacks from long term CO2-mediated forcings? In particular, it seems plausible to suggest that the magnitude and sign of short-wave (SW) feedbacks might differ substantially between the two phenomena.

    Consider El Nino responses as an example, where atmospheric elements respond to an increase in SST (as opposed to changes in SST occurring in response to perturbations originating in the atmosphere from changes in greenhouse gases, aerosols, etc.). Is it not likely that cloud responses mediating SW fluxes might result in negative SW fluxes (i.e. increased scattering to space) that would differ from responses to the long term forcings I mention? Some evidence for fairly strong responses of this type to El Nino’s was reported in JGR by Li et al – Li, G., and G. J. Zhang (2008), Understanding biases in shortwave cloud radiative forcing in the National Center for
    Atmospheric Research Community Atmosphere Model (CAM3) during El Nino, J. Geophys. Res., 113, D02103,
    doi:10.1029/2007JD008963.

    Would the long term forcings necessarily duplicate this phenomenon? If there is no compelling evidence to claim they would, it may be hazardous to extrapolate climate sensitivity estimates, however accurate, from short term internal climate variations to long term responses of the climate to increases in atmospheric CO2.