Problem 4: Why has certainty not improved 15


Problem 4. Why has a community of thousands or tens of thousands of climate scientists not managed to improve certainty in core areas in any significant way in more than a decade (eg the climate sensitivity caused by CO2 doubling as evidenced by little change in the IPCC bounds)?

This problem has been the hardest, probably because it takes enormous hubris to claim solution to a problem that defeats thousands of usually intelligent people. One man who does that is — Dr Roy Spencer — claiming a huge ‘blunder’ pervades the whole of climate science regarding the direction and magnitude of ocean-cloud feedback, the subject of his upcoming book and paper.

What I want to demonstrate is one of the issues that is almost totally forgotten in the global warming debate: long-term climate changes can be caused by short-term random cloud variations.

The main reason this counter-intuitive mechanism is possible is that the large heat capacity of the ocean retains a memory of past temperature change, and so it experiences a “random-walk” like behavior. It is not a true random walk because the temperature excursions from the average climate state are somewhat constrained by the temperature-dependent emission of infrared radiation to space.

As showed previously, an AR coefficient of 0.99 is sufficient to change a random walk behavior (AR=1) to the kind of mean-reverting behavior his model shows. This difference is virtually undetectable using the usual tests on the available 150 years of global temperature data. Global temperature cannot be a random walk, but it can be ‘almost a random walk’. It can also respond to random shocks, such as volcanic eruptions, and sudden injections of GHGs, and oscillating solar forcings while still retaining the random walk character.

In his latest post he shows how his model of the climate system produces almost random walk behaviour; the kind of behaviour we have dealt with in the last four parts of this series. He shows that millennial climate cycles CAN be driven by random cloud variations, showing the integrative statistical structure found in the real global temperature data.

The answer to the Problem 4 is, of course, that millennial climate cycles HAVE been driven by random cloud variations, which is not the same thing. To show that, it seems to me we don’t need to exclude CO2 as a substantial forcing factor in recent climate changes. It could be excluded by the dogma of Occam’s razor. It could also be excluded if the effect of injections of GHGs were shown to be fugitive, or if the effect was shown to be relatively minor and limited to the direct radiative effects, which is probably the most likely situation.

If an essentially stochastic trend is FALSELY attributed to a deterministic cause, then one would expect no progress in narrowing the confidence limits. A physical uncertainty is then lodged in an epistemic uncertainty, until the offending false assumption is removed.

The resulting system is not a ‘complex climate system’ but an essentially simple, additive system, the only problem remaining being the estimation of the magnitude of the various forcing effects. It is a SIMPLE system from a mathematical POV, as it is decomposable into independent causes, the only complication being the integrated, under-constrained observable effect.

  • Anonymous

    The more you write, the more comfort I find in the analogue I mentioned before about the human body.The cyclicities of heart rate and respiration rate can occur at different frequencies, sometimes one changing alone, sometimes both changing at the same time but to various extent (as when exertion increases). To take the analogy further, unless there is a shock like a wound with loss of blood ot loss of a lung, an increase in heart rate or respiration rate or both can lead to an increase in body temperature, which in turn can activate a feedback by perspiration. The onset of perspiration can be unpredictable or at least require some prior conditions and it interacts with data external to the body (like ambient air temperature and humidity).If you accept this analogy as a partial explanation of system complexity, you can see that although the system can, in theory, be modelled, there are many inputs that need measurement and some might not have been measured in the past – e.g. the type of clothing being worn. The external factors, if not adequately known or recognised, can make the modelling not only wrong, but impossible.Have we reached the impossible realisation stage in global climate models? I suspect it is starting to dawn.

    • cohenite

      Sherro, I do apologise; I was only joking about going to Deltoid; I see you did and were insulted for your troubles. The Monckton/Abrahams dispute seems to have legs with Monckton apparently wanting to take it further. The Abrahams ‘critique’ of Monckton seems to follow the Lambert method of approaching some author who Monckton has quoted and asking that author for a renunciation. This occured with Pinker where Monckton had used cloud forcing incorrectly and Lambert contacted Pinker, but as Steve Short has comprehensively pointed out, despite not using cloud forcing correctly Monckton was still correct about the ramifications of Pinker’s paper.

      Perhaps next time Monckton will call upon Spencer and Ramanathan for that matter, about the effect of clouds.

  • sherro

    The more you write, the more comfort I find in the analogue I mentioned before about the human body.The cyclicities of heart rate and respiration rate can occur at different frequencies, sometimes one changing alone, sometimes both changing at the same time but to various extent (as when exertion increases). To take the analogy further, unless there is a shock like a wound with loss of blood ot loss of a lung, an increase in heart rate or respiration rate or both can lead to an increase in body temperature, which in turn can activate a feedback by perspiration. The onset of perspiration can be unpredictable or at least require some prior conditions and it interacts with data external to the body (like ambient air temperature and humidity).If you accept this analogy as a partial explanation of system complexity, you can see that although the system can, in theory, be modelled, there are many inputs that need measurement and some might not have been measured in the past – e.g. the type of clothing being worn. The external factors, if not adequately known or recognised, can make the modelling not only wrong, but impossible.Have we reached the impossible realisation stage in global climate models? I suspect it is starting to dawn.

  • cohenite

    That’s a very interesting analogy sherro; you should road test it at Deltoid where, in a Monckton thread, the regulars are in a frenzy of declarations about policy dictates to deal with the obstinance of the laypeople and the usual denialist suspects. To extend your analogy, if the human race is a biological organism what are the AGW supporters?

    http://scienceblogs.com/deltoid/2010/05/monckton_is_wrong.php#comments

  • cohenite

    That's a very interesting analogy sherro; you should road test it at Deltoid where, in a Monckton thread, the regulars are in a frenzy of declarations about policy dictates to deal with the obstinance of the laypeople and the usual denialist suspects. To extend your analogy, if the human race is a biological organism what are the AGW supporters?http://scienceblogs.com/deltoid/2010/05/monckto

  • Anonymous

    Cohenite, No apology is needed, none at all. Many of us look around for interesting blogs and I had not visited Deltoid for a while. It was interesting to do a brief plumb of the depth of knowledge.

    It quite OK with me if doubters from either side get the straight answer to the straight question from the author of a referenced paper. That’s how I came to have some interesting emails from Phil Jones from a few years back.

    It’s a pleasure to work with Niche Modeling because the ad homs are essentially nil.

    A main point of my human body analogy is leading to triggers that cause changes in cyclicity rates. Obviously, in the global sense, Pinatubo was one. I suspect the modelling world to be missing others, less obvious ones.

  • cohenite

    Sherro, I do apologise; I was only joking about going to Deltoid; I see you did and were insulted for your troubles. The Monckton/Abrahams dispute seems to have legs with Monckton apparently wanting to take it further. The Abrahams 'critique' of Monckton seems to follow the Lambert method of approaching some author who Monckton has quoted and asking that author for a renunciation. This occured with Pinker where Monckton had used cloud forcing incorrectly and Lambert contacted Pinker, but as Steve Short has comprehensively pointed out, despite not using cloud forcing correctly Monckton was still correct about the ramifications of Pinker's paper.Perhaps next time Monckton will call upon Spencer and Ramanathan for that matter, about the effect of clouds.

  • sherro

    Cohenite, No apology is needed, none at all. Many of us look around for interesting blogs and I had not visited Deltoid for a while. It was interesting to do a brief plumb of the depth of knowledge.It quite OK with me if doubters from either side get the straight answer to the straight question from the author of a referenced paper. That's how I came to have some interesting emails from Phil Jones from a few years back.It's a pleasure to work with Niche Modeling because the ad homs are essentially nil.A main point of my human body analogy is leading to triggers that cause changes in cyclicity rates. Obviously, in the global sense, Pinatubo was one. I suspect the modelling world to be missing others, less obvious ones.

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