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Climate Hustle

Uncertainty in Global Warming Science

Posted on 26 June 2011 by hfranzen

Since the time of Kepler and Galileo there Galileohas been steady progress in the precision with which humans can predict the outcome of kinematic events.  As is well known, major advances were made by Newton and Einstein and today we can predict with extraordinary accuracy the trajectory of an object traveling with a known velocity under the influence of gravitational forces. 

This does not mean that the trajectory of a rocket traveling to Mars, for example, is known with absolute precision but is to some extent uncertain.  In part this uncertainty is introduced both by our inability to determine the velocity with perfect precision and by the perturbations of gravitational effects arising from  more distant objects.  

KeplerTherefore it is correct to say,  even in this very well understood case, that the results of the scientific calculation are “uncertain”.  Such uncertainty is a reality in all scientific calculations and those who depend upon the results of such calculations must be aware of this fact.  However in cases of the character of rocket trajectory calculations the uncertainties themselves are understood such that we can be very certain that a rocket meant to go to Mars will arrive there barring some unforeseen catastrophe such as an engine failure or a giant solar flare.

In the same fashion there are many areas in our lives (communication, GPS, air traffic control, cat scans, MRI, internal combustion, electric generation and transmission, radar, computer automation, etc.)  that depend upon the results of science and have associated with them uncertainties  that are both known and known to be negligible in terms of  the particular application to which the relevant science (electromagnetism, quantum mechanics, classical mechanics , etc.) is applied.  This is simply to state an obvious fact of our lives in the 21st century. In this essay I will distinguish between three types of science,

  • What I have briefly described above is a type of science that I will, for convenience, call Type A. I will take science to be of Type A if, in principal, the uncertainty in the result and the uncertainty in that uncertainty can be numerically calculated and the relative uncertainties in each can be determined to be less than some set percentage.
  • For me, then, Type B science depends on equations that are less precisely constrained than in Type A science.  In the case of Type B science there is difficulty in defining quantities and boundary conditions.  The equations in Type B science  cannot be solved with the same precision as for Type A and, equally important, the uncertainty in the uncertainty is frequently unknown.  An example of a result of Type B science is the prediction of weather.  We may be told, for example, that  there is a 75% chance of rain in our area. This “prediction” is based upon the understanding that meteorologists have of the basic equations governing the movement of air masses , the changes of temperature and pressure with such movement and the condensation of water  vapor, however the conditions limiting the equations in this case, the boundary conditions, are not so precisely defined and  the objects to which the equations apply not so well defined as in the previous cases.

    The conclusions of Type B science have a much greater range of relative uncertainty than for Type A. The 25% uncertainty suggested by the 75% probability would of course be totally unacceptable in a Type A calculation of, say, the osmotic pressure of an injected serum or the probability of a mid-air collision. Furthermore, the uncertainty in that 25% uncertainty in the weather itself is, from everyday experience, quite a bit larger than would be acceptable for placing a lander on Mars or determining the locations of neighboring planes in the vicinity of an airport.  This, by the way, is not to demean meteorology – given the complexity of the problem the meteorologists do a marvelous job!
  • Then there is Type C science.    A major tool of what I call Type C science is curve fitting.  One seeks to fit a curve  to data using parameters with no apriori physical meaning,  but that provide the smallest residual “error” .  In many cases it is the best that can be done, but the results are inevitably open to doubt.  An example is the growth of a population with time where an observer fits the data to a population vs. time curve and uses this to interpolate or extrapolate populations to times for which measurements are not available.  Such curves are always open to question even though in the hands of  skilled observers they may be used to reach significant conclusions (examples of Type C science are Malthus' population prediction and the Keeling Curve).

Now, finally, I will turn my attention to global warming.  My concern in this essay is that science of all three types is applied to global warming and frequently, when the validity of conclusions is under discussion, no distinction is made between the three types of science.  Taking the earth’s temperature as a function of time as an example, many deniers have focused on the uncertainties associated with the interpretation of tree ring or ice core data.  In my view this is acceptable to a certain extent.  Skepticism is a healthy component of scientific analysis and I believe that those who have made the measurements and compiled the data can and do adequately defend their conclusions.  But it is my personal view that global warming is based first and foremost upon the conclusion of Type A science (the interaction of the earth’s  Planck radiation with the rot-vib modes of atmospheric carbon dioxide and the experimental and theoretical determination of the extent of this interaction ). It is also my view that only upon the basis of Type A science is one able evaluate the Type C science inherent in fitting the earth’s temperature to time. 

A major problem, as I see it, is that when deniers question the Type C science without coming to grips with the underlying Type A science they can deceive themselves and others into believing that they are attacking the basic structure of global warming science whereas in reality they are just dealing with a detail in the superstructure. They may in fact be dealing with a detail within a detail, e.g. selecting for discussion a particular subset of data (“cherry picking”). On the other hand to deny the Type A science showing global warming without finding a flaw in the argument (see hfranzen.org for a basic discussion of the effect without feedbacks or interferences) is like saying , ”I accept almost all of mathematics but deny the validity of Euler’s Theorem”. Just as it would make sense to deny Euler’s Theorem only if one could disprove it, it makes no sense to deny global warming science without finding a logical flaw in the Type A science demonstrating GW while, as I claim almost everyone does, accepting the myriad results of Type A science that come into play in our daily lives. And further it makes no sense to attack the average earth temperature vs. time (hockey-stick) curve without first coming to grips with the Type A science of GW.  To my way of thinking the hockey stick is not the basis of GW science, it is derivative and confirmatory, and its basic correctness depends upon the fundamental Type A science underlying the temperature changes.

The gist of what I am saying is this – when deniers confront an issue dealing with Type C science they should be asked to first consider the question, “Do you accept the basic  conclusion of quantum mechanics and spectroscopy that global warming is occurring  right now?” If their answer is “no” than it seems to me that  it is Type A science that should be debated before tackling the Type C science.  If their answer is yes, then, importantly, it is not possible for them to take the fact of the debate as a demonstration that the major thrust of the science of global warming is basically flawed. Furthermore any discussion of some aspect of the Type C science can be meaningfully limited to the relevant issue without  trying to discuss the larger question of the validity of the underlying GW proposition.

In short, if a denier disputes the claims of the hockey stick and is unwilling to accept the basic science of absorption of infra-red radiation by carbon dioxide then it is fruitless to discuss the hockey stick with that denier.  On the other hand if they accept the basic science but deny the hockey stick then it can be worthwhile exploring  their concerns  and pointing out that the hockey stick result follows straightforwardly, if not rigorously, from the known increasing energy input into the earth.  In the discussion that follows they might  be able to present some basis for criticism of the hockey stick curve beyond the fact that they simply don’t want to believe in global warming, and if the criticism is valid this would be a win-win situation.

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Comments 51 to 86 out of 86:

  1. Camburn - You might also be interested in Benestad and Schmidt, 2009, where they examined Scafetta's simple regression method, found the reported error bars far too small, and concluded:

    "Our analysis shows that the most likely contribution from solar forcing a global warming is 7±1% for the 20th Century, and is negligible for the warming since 1980."
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  2. Camburn,

    Again, you are offering Dr. Svalsgaards paper as evidence... yet we cannot read it. We can only trust you, and your glowing endorsement of him as a scientist.

    He is a good scientist, from what I see... but I don't know why you simultaneously dismiss all of the other work (and the scientists who have come before him), yet put so much weight on a paper that has not yet been published... except that it obviously draws a conclusion which you'd like to see.

    I really don't care that you've read it, or what you think of it, or him. None of that is valid if I and the rest of the world can't see it.

    If you can't provide a link to a paper, you can't use it as evidence. That's how this game is played.

    Everything else is hearsay and inadmissible in the court of convincing anyone that you know what you're talking about.
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  3. Hi everyone! my first comment on the site. First off, thank you all for your efforts; I love this resource. Secondly, I try to communicate climate change to interested people who more often than not lack the formal training necessary to understand the three types of science posted in the article. My job has been to try and personalize and create stories/parables that people can feel into so that climate change moves beyond the alienating double talk of politicians and the cold abstract language of the likes contained within this thread.
    My question is, does someone have another way of characterizing the three kinds fo science in a way that is more approachable with examples of the kinds of science at that level? Imagine my market is dominated by aging baby boomers that sadly watch a lot of tv. They relate to stories much better than theories and facts.

    Thanks again!
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  4. Camburn:

    "It would seem Bertrand's research on solar agrees with Dr. Svalgaard.
    "Bertrand was investigating the effect of solar and volcanic influence on climate and concluded "these are clearly not sufficient to explain the observed 20th century warming and more specifically the warming trend which started at the beginning of the 1970s"."

    I don't think Camburn understands that the implication of Bertrand's research (assuming he cites it correctly) is that TSI hasn't caused the warming trend that started at the beginning of the 1970s. In other words "it's not the sun, rather than CO2". Strengthens, not weakens, the case of sensitivity to a doubling of CO2 being higher than denialists like Camburn so fervently want to believe.

    Now if Svaalgard's paper holds up over time, then yes, there's something not well understood about early 1900s warming. However, it's not claimed by climate scientists that the cause of this warming is perfectly understood.

    Camburn will be sure, though, that Svaalgard's *reconstruction* regarding TSI trumps all observations regarding CO2's role as a GHG, positive water vapor feedback, TOA satellite measurements, etc etc etc.
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  5. Camburn, Sphraerica

    TSI does not have to vary over the short to medium term - years to decades to cause a warming imbalance (Earth to gain energy).

    Since we don't really know the 'equilibrium TSI' at which Earth is not warming nor cooling in the absence of AG forcings, then we cannot accurately determine the gain or loss of energy from TSI.

    If TSI is above an 'equilibrium' value and stays constant -there is a constant imbalance in forcing which translates to a linearly increasing gain in energy - and a roughly linear gain in temperature of a fixed mass of ocean, dirt and air and phase change at constant temperature for ice and water.
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  6. 55, Ken,
    TSI does not have to vary over the short to medium term...
    Yes and no, but not all that relevant. I'd argue that yes, solar variation can only have so much impact on climate, and must involve a variation over a long time scale, but the 11 year cycle obviously does come into play on short time scales... but not really in climate.
    ...then we cannot accurately determine the gain or loss of energy from TSI.
    This is false.

    We just got done discussing the papers that attempt to estimate the energy imbalance. Declaring out of hand that we simply can't do so is just wrong.
    If TSI is...
    This is all rather simplistic conjecture and thought-modeling that does nothing to advance the conversation. Certainly, I don't believe you have anything that can support this simple model as a premise, or any conclusions that you might draw from it.
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  7. Camburn, Ken,

    In any event, all of this discussion of solar is OT. I know you'd like to claim that it has to do with uncertainty in climate science, but really, that pretty much sums up just about any denial argument there is. It would turn this thread into a denial free-for-all.

    We should close with Dr. Franzen's well framed characterization of the science, and perhaps turn to answering emilio's (relevant) question.
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  8. Ken Lambert - "If TSI is above an 'equilibrium' value and stays constant -there is a constant imbalance in forcing which translates to a linearly increasing gain in energy..."

    As has been pointed out more than once, Ken, a constant imbalance could only be maintained if the TSI was increasing (not 'constant') to stay ahead of the increasing TOA radiation to space due to increasing temperatures.

    That's not happening. We have excellent data on TSI, very precise in noting changes in insolation even if there are inter-satellite absolute calibration uncertainties - we simply do not have the constantly increasing insolation required to drive the temperature changes of the last 30-40 years. Your hypothesis is quite simply contradicted by the facts.

    I suggest taking additional comments in your ongoing TSI discussion back to it's the sun, where this has been repeatedly disproven.

    As a serious point, Ken, you seem to be unable to absorb any information on this topic. You've repeated the same incorrect assertions over and over and ... (repeat as necessary), and have had the errors in your hypotheses pointed out each time. Why do you continue to insist on this contrary to actual measurements?
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  9. Ken Lambert wrote: "If TSI is above an 'equilibrium' value and stays constant -there is a constant imbalance in forcing which translates to a linearly increasing gain in energy"

    This is simply incorrect, if there is an energy imbalance, global temperatures rise until the resulting increase in outbound IR is sufficient to restore the balance an a new equilibrium is established. Temperatures would not increase linearly, and neither would the gain in energy.

    We know the equilibrium value for atmospheric CO2 (about 280 ppm), if CO2 levels are maintained at a constant level above this equilibrium value, then again there will be an energy imbalance, but will temperatures increase indefinitely? No.

    So why is TSI forcing different from CO2 radiative forcing?

    N.B. I have pointed this out before without a getting a reply.
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  10. dhogaza:
    Yep, you are understanding it.

    TSI can not explain the early 20th century warming.
    Nor can it explain the decline in warmth....nor the increase again in warmth.

    I don't know if Svalgaard will trump all other papers. His will be another addition. There are so many different reconstructions of TSI that have been published who knows?
    He is eminent in his field, has come up with a solution to the wide variance in the published works that seems very plausable. The bulk of the latest evidence is leaning in his direction tho.
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  11. Kevin C.: Thanks for your commment and questions. The catagories of science that I propose are totally my own and are presented with the purpose of trying to rationalize arguments about the science of GW. To my way of thinking there is a heirarchy of arguments about GW science, namely: 1. about science with uncertainties
    that can be numerically determined and shown to be negligible(Type A), 2. about those concerning science with larger uncertainties that are basically estimates based upon past experience (Type B) and 3. those about science which describes phenomena in terms of a curve fitted to data using empirical curve fitting (Type C). I express the opinion that to disagree with the results of Type C science and infer or conclude that this disagreement is tatmount to disagreeing with the totality of GW science is not productive. That is, someone who wishes to deny GW science should be very explict about the level of their disagreement in the heirarchy. For example, if one wishes to express a criticism of the earth's temperature vs. time curve during some particular epoch it would be very helpful to all involved if they would make clear at the outset at what point in the heirarchy they part ways with the accepted scientific picture. The nature of the discussion will, I think, be very different if they say at the outset that they simply do not believe CO2 has anything to do with GW as opposed to saying that they understand and agree with the basic understanding of the interaction of the earth's Planck radiation with atmospheric CO2 but want to raise a specific point about the interpretation of the specific data for that epoch.
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  12. emelio.gagliardi: Since I wrote the essay I guess I should provide an aswer to at least the first half of your question. Some examples of Type A science that occur to me "off the cuff" are: rocket trajectory, clectial mechanics, partical trjectories, electron orbits in atoms and molecules, sunchroton trajectories, atomic and molecular spectra. Some examples of Type B science are: weather prediction, river bank errosion, corrosion, automobile traffic flow, disease transmission. For Type C science I would suggest: population growth, the Keeling curve, the trajectory of an arrow, the earth's temperature vs. time. melting of an ice sheet. I want to congratulate you on your conern about communicating GW science to the general public - this is an extremely important activity! However I am afraid that contributing ideas about how to discuss this topic in a fashion better suited to technically uninformed audience is beyond my ability,
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  13. Sphaerica, KR, DM

    I was only discussing the radiative forcing side of the ledger, and from TSI only.

    For sure S-B and other feedbacks (WV & Ice Albedo) will increase the outgoing 'climate response' side of the ledger to bring about a new equilibrium at a higher temperature. I have mentioned this elsewhere many times.

    For sure you cannot measure individually the radiative forcings in the climate system as listed in Fig 2.4 of AR4.

    They are modelled and theoretical individual warming and cooling forcings which add up to a total of about +1.6W/sq.m.

    My point is that the TSI contribution is really unknown unless you know the 'equilibrium' TSI which will produce neither warming not cooling in the absence of all the other AG forcings.

    Looking at the 'differences' in TSI which can be done with 'high precision' satellite measurement is only relevant if you know the 'equilibrium TSI'.
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  14. Ken Lambert - I have responded on the far more appropriate It's the sun thread.

    Now, can we get back to the uncertainty discussion?
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  15. Ken Lambert It is fine to talk about the "radiative forcing side of the ledger" (except that CO2 also gives rise to radiative forcing), however if you only look at one forcing in isolation and ignore the feedback from that change in forcing (that would restore radiative equilibrium), then it is hard to see how any conclusion you might draw has any useful bearing on the discussion (as it would only apply to a planet with physics very different from that which applies on ours).

    "My point is that the TSI contribution is really unknown unless you know the 'equilibrium' TSI which will produce neither warming not cooling in the absence of all the other AG forcings."

    This point is incorrect as forcings are defined as a change from pre-industial levels. Satelite data gives higher precision estimates of TSI, that doesn't mean we don't know anything abou TSI prior to the satelite record.
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  16. Ken Lambert Jut out of curiosity, is the "constant energy difference" idea based on the idea that you can regress global temperatures reasonably well as a function of integrated TSI? If so, it is well worth asking what is the physical mechanism that would mean that TSI affects the climate by long term integrated, rather than direct forcing? It is straightforward to construct accurate regression models by casting around to find variables that look correlated (or to manipulate them by e.g. integrating to make them look correlated). However this ends up over-fitting (you have as many degrees of freedom as the number of variables or manipulations of variables that you consider), which generally means the model has poor predictive value. As (effectively) a statistician, I can tell you there is no reason to be impressed by the fit of such models, unless physics suggests that form of model is justfiable.
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  17. I - like Cambrun - I agree that we now have a significant and rapid GW, that currently GW (and formerly) can not be explained by climate change without GHG's.
    Uncertainties the type "C", however, are very significant.
    These "uncertainties" in the "fitting curve" have the effect of significant errors in risk assessment and risk management.

    Camburn (synthesizing) mainly says: The main uncertainty concerns the natural influences on climate - especially the Sun.
    Practically same way - also - concludes NOAA:“ Our understanding of the indirect effects of changes in solar output and feedbacks in the climate system is minimal

    @KR
    If not Scafetta - may we quote - Beer et al., 2000., The role of the sun in climate forcing: “If one computes the global and annual mean of solar forcing caused by the 100 kyr period of eccentricity one gets an amplitude of in the spherical mean. This value is too small to be detected in climate records. But, despite the tiny global forcing value, we can observe the 100 kyr frequency during the last 800 kyr in most paleoclimatic records. The global mean temperature changes between glacial and interglacial periods are large: about 20C for polar (Johnsen et al., 1995) and 5 for tropical regions (Stute et al., 1995).”

    "0.12Wm ~ 2" - so would sometimes even multiply by 100 (!) - for the sum of direct and "indirect effects" influence of the Sun in palaeoclimate?

    Let us look at uncertainties based on an interesting example. The rotational motion of the earth. The authors of this figure: , on this basis - in this paper, write: “...the LOD [Length of Day] fluctuations are largely attributed to core-mantle interactions and that the SAT is strongly anticorrelated with the decadal LOD. It is shown here that 1) the correlation among these three quantities exists until 1930, at which time anthropogenic forcing becomes highly significant ...”
    All right ..., just that newer data (LOD) - from 198? year - are completely different from those shown on the aforementioned figure.

    If the author of the Wikipedia chart is right - that is, its graph - "curve" - is more "fit" - the true - is to "present day" - we have a (sometimes shifted in time - it's true) excellent correlation (ie anti-correlation ) - shorter day = higher temperature.
    What it can affect the climate? Earth rotating faster, the heat transport is closer to the poles (as in a glass - when we quickly mix tea ...), so the increase of CO2 added to the atmosphere with melted the "ancient" permafrost ...

    Kevin Trenberth ( More knowledge, less certainty, 2010.):

    „So here is my prediction: the uncertainty in AR5′s climate predictions and projections will be much greater than in previous IPCC reports ...”
    “But while our knowledge of certain factors does increase, so does our understanding of factors we previously did not account for or even recognize.

    Sk.S. - skeptic, "denier", to the IPCC, and "mainstream" climate science?
    I think that - at least in some significant points type “C”- certainly yes.
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  18. DM #65,66

    "If so, it is well worth asking what is the physical mechanism that would mean that TSI affects the climate by long term integrated, rather than direct forcing?"

    TSI is a power unit (W/sq.m) - energy/unit time. Integrating it wrt time will give the total energy under the TSI curve between times t1 and t2.

    Energy will be absorbed in the system by two main mechanisms - mass x specific heat x Delta T (temperature increase in water, land, air) and phase change in ice or water at constant temperature (mass x latent heats of ice melt or water vaporization).
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  19. Arkadiusz Semczyszak - I don't believe this thread is appropriate to discuss Milankovitch cycles - but you are raising a red herring, a distraction from the subject, by claiming that any uncertainties in the glacial cycle (occurring on a time frame 10's of thousands of years) has anything to do with the current global warming (occurring over the last century).

    I sincerely hope this red herring is simply an error, and not a deliberate misdirection.

    ---

    Ken Lambert - "TSI is a power unit (W/sq.m) - energy/unit time. Integrating it wrt time will give the total energy under the TSI curve between times t1 and t2."

    And again you look at TSI in isolation, not considering the response of the climate. You are directly asserting a constant imbalance, requiring a constantly changing TSI - and that.is.not.the.case.

    More properly, you should state that "integrating the imbalance between TSI and TOA radiation wrt time will give the total energy change of the climate" - a much different question, particularly since we know the changes in TSI since the pre-industrial level quite well, and hence must look elsewhere for the imbalance leading to climate change.


    Moderators - I sometimes feel the need for a 'bit bucket' for arguments that have been refuted a thousand times...
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    Moderator Response: (DB) The TSI/TOA/equilibria bit has indeed been "Point Refuted A Thousand Times" (PRATT); the conclusion is becoming inscapable that KL is purposefully conflating the issue.
  20. Ken Lambert The same applies to outbound fluxes. Also, as I pointed out, the same is true for CO2 radiative forcing. Does CO2 being above its long term equilibrium value cause indefinitely increasing temperatures? No, but the integral is similarly "the total energy under the CO2 radiative forcing curve between times t1 and t2".
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  21. KR & DM

    DM - Yes the same is true for CO2 radiative forcing and all the other AG forcings.

    All the Radiative Forcings in Fig 2.4 of AR4 are 'looked at in isolation'.

    In AR4, CO2GHG is estimated at about +1.66W/sq.m, Aerosols estimated at -1.3W/sq.m, Solar (TSI) at +0.12W/sq.m etc, etc

    That is how the sum of all AG radiative forcings is computed. In AR4 the sum is +1.6W/sq.m.

    The climate response forcings are S-B (-2.8W/sq.m and WV + Ice Albedo Feedback at +2.1W/sq.m) (Trenberth).

    Total forcings: Radiative + TSI: +1.6W/sq.m
    Total responses: S-B + WV etc: -0.7W/sq.m
    Net Imbalance: +0.9W/sq.m

    This Net Imbalance has been reduced by Hansen to 0.59W/sq.m 2005-10, due to his assumed increase in Aerosols and other factors.

    These are instantaneous (power) quantities. To get the history of the energy added - you need to look at all the forcing curves wrt time (in isolation) and add them together to produce a composite curve.

    All the AG forcing curves are grounded to zero because they did not exist in AD1750. The TSI curve is not. We don't know if the TSI was producing 'equilibrium' or zero imbalance in AD1750, hence the area under its curve is an unknown component in the composite forcing curve over time.

    This is one of the uncertainties relevant to this thread.
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  22. KL:
    Some of the variables in climate that we are learning, but are resisted every step of the way....I call the "Oliver Heaviside" variables.
    He faced an uphill battle against the "established" at the time. He was right.....they were wrong.
    The Royal Society would not even grant him membership...a true travesty as he had a most wonderful mind.
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  23. I am wrong in my previous post. The Royal Society granted him membership in 1891.
    He did face an uphill battle with his ideas etc as they were radical at the time.
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  24. Ken Lambert

    You are still ignoring the point that the integrated forcing gives a deeply misleading picture because it ignores the fact that outbound IR increases and restores a (different) radiative equilibrium. There isn't much point in discussing the more subtle issues with you if you repeatedly turn a blind eye to your fundamental misunderstanding.

    The same story is true for CO2 (pointing out that they are estimated independently is transparently a red herring), but I suspect you would be up in arms if we were to go on about the area under the CO2 radiative forcing curve.
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  25. Camburn I suspect Heaviside would have gone for a physics based mathematical model to decide whether integrated forcings were relevant. As he was very good with his differential equations, I suspect he could have easily shown that they are not, as he would undoubtedly have included the terms representing outbound IR. It isn't rocket science.
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  26. Camburn Heaviside is a good name to mention in a thread on uncertainty in science, as he apparently once said "Shall I refuse my dinner because I do not fully understand the process of digestion?". Rather apposite I thought! ;o)
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  27. DM #74

    I have not ignored he outgoing IR.

    I said: "These are instantaneous (power) quantities. To get the history of the energy added - you need to look at all the forcing curves wrt time (in isolation) and add them together to produce a composite curve."

    "All the forcing curves" includes the S-B IR curve which has a time point value (2005) of -2.8W/sq.m for a rise in temperature of about 0.8degC since AD1750 (Trenberth).

    "There isn't much point in discussing the more subtle issues with you if you repeatedly turn a blind eye to your fundamental misunderstanding"

    You are mistaken in trying to suggest that I have only condsidered the warming forcings and ignored the major cooling forcing of S-B. Please re-read #71.

    "The same story is true for CO2 (pointing out that they are estimated independently is transparently a red herring), but I suspect you would be up in arms if we were to go on about the area under the CO2 radiative forcing curve."

    No I would not be 'up in arms' - I would suggest that all the forcings identified in AR4 (including CO2GHG) need be treated the same way - their time series curves added into a composite with the 'climate responses' ie. "The climate response forcings are S-B (-2.8W/sq.m) and WV + Ice Albedo Feedback at (+2.1W/sq.m) (Trenberth)."
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  28. KR #69

    "More properly, you should state that "integrating the imbalance between TSI and TOA radiation wrt time will give the total energy change of the climate" - a much different question, particularly since we know the changes in TSI since the pre-industrial level quite well, and hence must look elsewhere for the imbalance leading to climate change."

    That does not make sense. "TOA radiation" I assume to mean the net imbalance.

    TSI (divided by 4 and multiplied by 0.7) is the incoming solar radiation, and is a component of the warming and cooling forcings which make up the imbalance.

    Taking the difference between a component (TSI) and the overall net imbalance of all the forcings does not make sense.

    "Moderator Response: (DB) The TSI/TOA/equilibria bit has indeed been "Point Refuted A Thousand Times" (PRATT); the conclusion is becoming inscapable that KL is purposefully conflating the issue."

    Daniel - don't prejudge the outcome of a discussion before it has developed - you might be wrong.
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    Response:

    [DB] "you might be wrong"

    Wouldn't be the first - or last - time.  :)

  29. Ken Lambert - "That does not make sense. "TOA radiation" I assume to mean the net imbalance."

    That would be incorrect. What I was saying is that the integral of the imbalance (between energy received from the sun and that radiated into space as IR from the top of the atmosphere, TOA) over time gives the total change in climate energy - basic conservation of energy. My apologies if that was unclear.

    I don't quite understand how you went from TOA radiation to space to net imbalance.

    ---

    That said, your repeated claim that 'integral of TSI explains all' (paraphrasing) is indeed a PRATT.
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  30. KR #79

    "That said, your repeated claim that 'integral of TSI explains all' (paraphrasing) is indeed a PRATT"

    I have not claimed that 'integral of TSI explains all'.

    What I have said is that integral of ALL the AR4 forcings over time (they all should have a time history and a projection forward) added to the same integral of the climate responses over time will give the total energy added to the earth system. Volcanic negative forcing also adds to this sum (the area under the spikes).

    In other words we are summing the net forcing imbalance over time to get the total energy added to the system.

    Because TSI has no equilibrium baseline - the area under its forcing curve is uncertain so its contribution to the energy sum is unknown.

    Temperature and phase change of the masses engaged will respond to this energy total somewhere in the system.
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  31. Ken Lambert - "Because TSI has no equilibrium baseline - the area under its forcing curve is uncertain so its contribution to the energy sum is unknown."

    You are correct in that no matter when we start considering forcing anomalies, it's going to be difficult to find a point where the climate was at equilibrium.

    However, we have the track record of global temperatures, and a decent record of forcing changes both natural and human. We can see when the climate is gaining or losing energy over the last few hundred years. Global temperatures have gone both down and up over that period, which immediately tells us that we've seen forcings both above and below equilibrium - that the area under the forcing curve has gone both positive and negative.

    Given that simple piece of information, and looking at changes in forcings, we actually have a pretty good idea of the relative magnitude of the various forcing changes that are currently affecting climate. They are currently positive, we know when they were negative, and we've measured the changes. The big uncertainties at this point are indirect aerosol effects and cloud feedback - certainly not solar input.

    You seem to repeatedly call for 'more information', to state 'we cannot know' - this all sounds like a call for inaction in the face of what is actually pretty solid evidence.
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  32. Ken, the IPCC discuss the "instantaneous" forcings as that is the presentation that is most easily understood. Now if you want to see what happens when they are integrated, look at the output of a GCM, that is exactly what they are designed to do.

    I have pointed out that S-B outbound IR increases, and yes you have mentioned them, however what you have not done is demonstrate that the increase in outbound IR does not equilibriate fast enough that any uncertainty in absolute TSI from pre-industrial equilibrium would not by now be of negligible significance.

    Now if you don't like GCMs, then your remaining option would be to contruct a simple idealised model of the climate (such as those described in the first few chapters of Ray Pierrehumbert's book). If you could construct such a model, where the parameters were physically plausible and broadly consistent with observations, then we would have something we could work on. Until then, you are essentially just arm waving, you may have a point, but you need to do some science to back it up.

    Note the IPCC reports were written by leading experts on this stuff; I hope it has ocurred to you that there may be some physics that they understand rather better than you do, and that you might be very wrong.
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  33. KR wrote: "Dikran - Well said, and thanks for the Pierrehumbert book reference; I've just ordered it."

    Sorry KR, hit the wrong button, mea maxima culpa! It is indeed an excellent book, but rather hard going. I'd recommend it to anyone wanting to look a bit more deeply into the physics, although a recommendation from one of the physicists here would carry more weight!
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  34. Dikran - That's alright, I've had my posts deleted before. Although I hope it's the first time it's happened by accident!

    As to Pierrehumbert being hard going, that's OK. I read his recent Physics Today article, and don't have any illusions about him oversimplifying things. Time to take my neurons out for a few push-ups, anyway.
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  35. KR #81

    "However, we have the track record of global temperatures, and a decent record of forcing changes both natural and human. We can see when the climate is gaining or losing energy over the last few hundred years. Global temperatures have gone both down and up over that period, which immediately tells us that we've seen forcings both above and below equilibrium - that the area under the forcing curve has gone both positive and negative."

    Please expand on the 'cooling' we have seen over the last 'few hundred' years and the reasons for same.

    S-B is a fourth power function of T so you would see most of the effect in the last 50 years or so.
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  36. Ken Lambert - "Please expand on the 'cooling' we have seen over the last 'few hundred' years and the reasons for same."

    I believe you are being disingenuous here, Ken. I would point out the Little Ice Age - volcanic and solar forcings identified as major factors, as in Free and Robock 1999, and the mid-20th century cooling - primarily due to aerosol effects outweighing other factors from the 40's to the early 70's. Not a single 'cooling', but rather multiple ups and downs over the last few hundred years.

    There is no ongoing baseline TSI imbalance that we have not accounted for - we have data covering both climate warming and cooling, meaning imbalances both postive and negative, and there is no leftover such as the one you have (repeatedly) postulated.
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