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• DAVID FAIRBAIRN

  TEMPERATURE RISE PREDICTIONS The forecasts of temperature gain over the century produced by modelling can be shown to have two components, one having a high degree of predictability and the other being highly problematic. The Greenhouse Gas theory is responsible for the first component and may be reasonably regarded as ‘settled science’. It states that an increase of CO2 in the atmosphere will generate a ‘forcing rate’, the direct result of which may be expected to produce a sufficient increase in the energy retained by the earth to cause a rise in surface temperature over the course of a century that we may identify as GG degrees C. This is the direct outcome of the operation of the Greenhouse Gas principle and has been calculated to be 1.2 degree C This is the primary consequence. There are however secondary consequences, none of which are explicable by the Greenhouse Theory as such, but are dealt with by other branches of scientific knowledge. These secondary factors, of which there are potentially many, may be identified as x1,x2, x3 etc and the net sum of them all identified as X. Each of these factors may either be of the nature of a feedback or may be an independent variable. A positive feedback arises where the factor is itself directly related to the increase in heat generated as GG. Examining the models used by the IPCC shows that the value of X derived from these models lie within a range where X is at the low end 50% of GG and at the high end 500% of GG. These therefore yield predictions of warming within the century of between 1.8 and 6 degrees C. These models, being constructed to yield predictions of the consequences of CO2 increase, deal only in X factors that are of the nature of positive feedback. It is this that accounts for the wide range of prediction, even though the models are very similar and the parameters introduced into them reflect a very much less extreme variation in the assessments made by scientists. This can be readily shown by considering a positive feedback incidence of an X factor where its initial value, that is the secondary effect taken in isolation, is 40% of GG. This will now generate a tertiary effect of 16%, and a further effect at 4 removes of 6.4%. At 5 removes this becomes 2.5% and at 6 it is a further 1%. As a result a model into which is fed a parameter assuming a 40% primary positive feedback will generate a total temperature gain of approximately two thirds. This acceleration of the predicted gain gathers momentum very quickly. As the original assumption approaches 100%, that is a positive feedback just doubling the temperature gain at the first pass, it causes the model to yield a prediction approaching infinity. It is of course this characteristic, which is mathematical and owes nothing to any empirical observation, that gives rise to talk of ‘runaway’ tipping points. We can therefore see that the relatively modest differences in the assessment of feedback components introduced by different scientists yields results that verge on the bizarre. Those familiar with the use of modelling for business forecasting will be painfully familiar with this phenomenon. A modest tweaking of the input can give you almost any result you want, but unless the inputs and their variation are derived from hard, observable fact you are simply not dealing with the real world at all. That is not of course to say that the X factor is unimportant. Quite the converse it is crucially significant. The question that has to be addressed is not whether the 1.2 degree C as derived from the application of the Greenhouse Gas theory is correct (it is sensible to assume that it is) but what is the net effect of the multiplicity of X factors which must then be applied to yield any kind of usable forecast. The first point to be made is that, if we are wanting a real forecast and are not just playing modelling games, then those X factors which are NOT feedback elements but are independent must be given equal weighting. The exclusive concentration on the Greenhouse Gas theory, implicit in such models, means that all the other potential X factors are discounted. It is significant however that they have had to be brought back into the equation by the IPCC in order to explain why the temperature outcome of the last decade is so far adrift from that predicted by the models. The second point is that the operation of the feedback x factors must be validated by empirical observation, both in terms of their quantitative effect and the reality of the causal linkage with the primary GG factor assumed when assigning them feedback status. To describe the science of these assessments as in any way ‘settled’ is absurd given the immense complexity and metrication difficulties entailed. If there is one overall ‘law’ of nature that deserves to be observed when confronted with such an enigma it has to be the law of entropy. It is the operation of this law that causes so much of the natural world to be constantly moving towards a state of equilibrium, recovering over time from disturbances to that state. As a general statement it can be asserted that nature just doesn’t do tipping points. Given a perturbation amounting over a century to the injection of incremental energy capable of yielding a 1.2 degree C warming in the atmosphere, it is more likely that the secondary and further effects will be of the nature of negative rather than positive feedback. We are certainly not entitled to assume either without having collected and analysed empirical evidence. The IPCC emphatically does not have that evidence. It has fallen back on the device of seeking to carry over the degree of certainty reasonably attributable to the Greenhouse Gas theory in yielding the 1.2 degree C number to the estimation of the X factors then applied to generate the scary, and very wobbly, prediction of warming. This is thoroughly bad science. At the heart of this aberration lies a semantic trick, all the more effective because, like a good card trick, it is so difficult to spot. The amount of additional energy added to the earth’s total complement as identified as necessarily occurring through the operation of the Greenhouse Gas principle, must of necessity add to global temperature, that being the mean temperature of the globe. The issue now becomes one of distribution, that is how that energy becomes dispersed across the 5.974 x 1024 kg mass of the globe, and most particularly how much of it is retained in the form of a temperature gain in the 5.148 x 1018 kg mass of the atmosphere. To obfuscate this issue the IPCC has adopted the practice of using the SAME WORDS to identify the temperature of the latter as the former. In both cases the term ‘global mean temperature’ is applied. This is readily demonstrable by examining the 26 words of the IPCC conclusion that uses the term to identify mean surface temperature, and uses it in the same way 14 times in the preceding more detailed chapter. It is impossible to derive scientific truth from such a blatant misuse and distortion of terminology. We here see the term identifying the entity to whose variation in temperature we can assign a degree of certainty ‘flipped’ to designate an entity that merits no such attribution of scientific likelihood let alone certainty. The reality is that, as a consequence of a rise in CO2 concentration in the atmosphere, we must expect over a century a gain in energy which, if remaining resident in the atmosphere, would cause a temperature rise of 1.2 degrees C. There are however both other unrelated factors that may cause the temperature to be higher or lower, and factors arising as secondary consequences of any temperature rise that may again act either to increase or decrease the resultant net effect. We do not currently have nearly enough scientific knowledge nor evidence to be able to make any confident prediction of the outcome.