Tuesday, June 17, 2014

David Evans' notch-filter theory of the climate is infinitely fine-tuned

The required notch filter itself is the key disease showing that the particular solar model is almost certainly incorrect

More than two months ago, Jo Nova's partner David Evans sent a group of people including your humble correspondent impressively looking and formally convincing documents about a new solar theory of the climate. I have spent many hours with reading them and thinking about them, exchanging e-mails with David, and so on. Because the documents were rather long, I needed an hour at the very beginning to see what the model really says, but that was followed by many other hours of reading.

Sometime on the second day, I became pretty much certain that the model is wrong. At that time, I should have stopped all interactions because they were unlikely to be constructive and I was at risk that I wouldn't even be thanked for the intense hours even though David would tell me he was incorporating my feedback – and this worry seems to have materialized, indeed. Not that it's too important! ;-) I did stop spending my time a few days later, anyway.

More importantly, I think that the climate cannot work like that and if you look how the theory works and what is used as evidence in favor of the theory, it's very clear that there is no evidence at all. Now when the theory is no longer embargoed, see big news I and big news II on Jo Nova's blog, let me summarize the model a little bit concisely.

David's goal is to claim that the whole evolution of the global mean temperature – or a big portion of it, to say the least – and especially the 20th century global warming and its various intense episodes may be due to the Sun. Not just the Sun. He specifically means the total output of the Sun, the total solar irradiance (TSI). I will use the symbol \(P(t)\) for this total irradiance. After all, it's the power of a sort.

\(P(t)\), the TSI, is expressed in watts per squared meter. Up to an additive shift, the graph of \(P(t)\) since the year 1600 AD or so looked something like this:

Clicking any graph will magnify it.

You see that the solar output is oscillating with an approximately 11-year periodicity. That's the periodicity associated with the changing polarity of the Sun's inner magnet. The magnet goes up and down and it takes 22 years or so to return to the original up position. The sign of the Sun's magnetic field doesn't matter much, at least not for the number of sunspots, so the effective periodicity of the observable quantities including \(P(t)\) is 11 years or so, not 22 years.

Aside from the 11-year cycle, the graph – largely extracted from the counting of the sunspots and the known correlations between sunspots and the TSI – shows longer periods of a relative silence of the Sun. They (the Maunder minimum and the Dalton minimum) apparently coincide with the little ice age and the cool early 19th century. I do find it conceivable if not likely that these correlations between the solar activity and the cold eras are more than coincidences and there may be some very slow causal, solar-driven mechanism changing the climate at the longer-than-decadal timescales. What I have a problem with is the "notch filter" part of David's claim.

He says that the graph \(P(t)\) above drives the Earth's global mean temperature which looked like this since 1600 AD:

By "driving", he effectively means that this temperature \(T(t)\) at some moment \(t\) is a linear combination of the solar outputs at all the previous moments:\[

T(t) = \int_0^\infty dt'\, R(t') P(t-t').

\] I explicitly wrote the integral so that the delay of the response \(t'\) is a positive number but you should really imagine that the integral goes from \(-\infty\) to \(+\infty\) and the response function – the function containing the coefficients \(R(t')\) – is zero for negative values of \(t'\).

David's theory is then fully specified by the response function \(R(t')\) – he calls it the "transfer function" but I am used to the term "response function" which is why I use it all the time. OK, what is the response function with which his model predicts correct global mean temperatures as a function of the total solar irradiance? Using various algorithms and choices to cut the data, its Fourier transform of the response function \(\tilde R(f)\) as a function of the frequency \(f\) (the periodicity is \(1/f\)) looks like this:

At the beginning, what impressed me is that different choices of the periods of time and different methodologies to calculate \(\tilde R(f)\) give you pretty much the same result. The function has the sharp local minimum near \(1/f=11\,{\rm years}\). This minimum is what justifies the adjective "notch" in front of the "filter" ("filter" means that the hypothesized relationship is expressed via a response function). But within a day, I came fully back to my senses. It's obvious why the sharp minimum is there in all the versions of the graph. Why is it there?

Simply because the integral equation above says that the temperature \(T(t)\) is the convolution of the response function \(R(t')\) and the total solar output \(P(t)\). If you know some basic calculus of Fourier transforms and convolutions, or if you're ready to check it using some verifiable identities for integrals, you will agree that the Fourier transform of the convolution is the product of Fourier transforms. So translating my previous integral equation which may be schematically rewritten (using the star as a symbol of the convolution) as\[

T(t) = R(t) * P(t)

\] to the frequency representation gives\[

\tilde T(f) = \tilde R(f) \tilde P(f)

\] up to some irrelevant, convention-dependent normalization factors, minus signs in frequencies, and/or complex conjugations if needed. That's great because the Evans response function in the frequency representation may be simply calculated as\[

\tilde R(f) = \frac{ \tilde T(f)}{\tilde P(f)}.

\] This frequency-based Evans response function is simply the ratio of the Fourier-transformed global mean temperature and the Fourier-transformed solar output! Because the Fourier-transformed solar output has a peak (maximum) near the period \(1/f\) of 11 years and because this Fourier transform appears in the denominator, \(R(f)\) will obviously have a similar minimum over there. The response function \(\tilde R(f)\) will go close to zero for \(1/f\) close to 11 years. It has to go to zero because it's needed to suppress the effect of the 11-year cycle that is seen in the sunspots and the TSI but that isn't seen in the global mean temperature!

I think that many of you will agree that the marketing point used as the title on Jo's blog
For the first time – a mysterious notch filter found in the climate
is pure demagogy. What the near-vanishing of \(\tilde R(f)\) for \(1/f\) close to 11 years really means is that the most obvious possible proof of the direct effect of the total solar irradiance doesn't exist – the 11-year cycle isn't present in the temperature data. This is a problem – potentially a huge problem – for any theory that tries to present the solar output as the primary driver even at the decadal scale and faster scales. It's surely nothing to boast about. It makes the solar theory of the climate much less likely, not more likely. Suggesting otherwise is a case of demagogy.

Still, you might be impressed that the response functions that I repeat for your convenience

always come out very similar, very close to the relatively narrow grey strip. At least I was intrigued by this observation. However, you should realize that the vertical axis is logarithmic and the strip goes from \(1k\) to \(3k\) for some \(k\in \RR\): the response function for the given frequency is nearly tripled if you go from the grey strip's lower end to its upper end. The numbers in the interval \((1k,3k)\) may be written as \(2k\pm 1k\), so the relative standard deviation is about 50 percent. No wonder that for most frequencies in most reconstructions, the response function may be written as the averaged one plus minus fifty percent. The accuracy with which you hit the grey strip is completely unspectacular.

In other words, there is certainly no precision evidence – and probably no significant evidence at all – that there exists any universal function \(\tilde R(f)\) that would describe the behavior of the hypothetical solar-driven climate. The right function \(\tilde R(f)\) needed to "predict" the right data is directly calculated from the data and its detailed values will depend on which intervals of time and which data you will try to use (TSI in some period) and "predict" (temperature in some period). \(\tilde R(f)\) is the ratio of two functions that have pretty much nothing to do with one another. The only universal feature is that the denominator is amplified near \(1/f\) equal to 11 years, so the ratio will be suppressed for the same frequencies and for the same reason.

This is the basic sketch explaining why I don't believe that there is anything correct about the notch-filter theory. There are climate skeptics who will endorse any claim or idea that goes against the "consensus". I am surely not one of them and I think that this theory is approximately as unjustifiable as the theory that we will face a climate catastrophe before 2100 which is why I am critical to both.

Natural mechanisms on Earth just won't produce a response function that happens to vanish exactly for the 11-year periodicity!

That's especially the case because the value 11 years for the periodicity isn't even quite constant. If the "notch filter" on the Earth were programmed to kill the 11-year cycle, it would still fail to kill the 10-year cycle comparably accurately and because the cycles sometimes take 10 years only and the Fourier transform of TSI is still rather high for \(1/f=10\,{\rm years}\), the temperature record should have a peak near that value, anyway. It doesn't.

The sub-decadal and similarly fast oscillations of the climate don't have anything to do with the TSI.

David is making lots of other claims that go beyond the simple model of the response function. For example, the warming between the late 1970s and late 1990s is explained by "his theory", too. I don't see any evidence for that at all. The warming is predicted if the response function and the delay is appropriately fine-tuned so that the prediction appears. But this is not an explanation. It's just a replacement of one fact by another, equivalent fact in an unnatural parameterization of the same variables. There should exist a simplified explanation why such a solar model produced warming since the late 1970s and I don't think that he has one.

Similarly, he postulates that the most intense cooling in the last 4 centuries is imminent. I don't see how it can follow from any arguments related to this theory. Again, for some choices of \(R(t)\) including the most represented delay, one might get a significant cooling. For most others, one doesn't get it. If one gets such a prediction regardless of the data, it's clearly a numerical artifact resulting from the fact that the functions \(P(t)\) and \(T(t)\) are not known for all \(t\in\RR\) but only in an interval. This inevitably leads to some unphysical behavior near the edges. Experts in signal processing would talk about ringing artifacts. Ironically enough, I think that David's prediction of a dramatic imminent cooling is the result of the same "ringing artifact" as some of the failed numerical model-based predictions of a dramatic imminent global warming. Non-engineers and more formally trained people will call this particular thing the Gibbs phenomenon. One must be very careful whether he believes what he predicts near the edges if his model were obtained from the data that were truncated at these edges!

Thanks to his background, David talks about the "notch filter" and electric circuits that would emulate the same response function that suppresses the given frequencies. But he doesn't actually even have the electric circuit that behaves in this way (although you may surely design a sufficiently complicated one, involving transistors as well as capacitors and resistors and coils, that would behave like that). But even if he had one, that would be very far from having evidence that the Earth's climate is mathematically analogous to that circuit.

So he's really not just one level but two levels from having anything that could count as a physical justification of the model. Not only the physical mechanisms based on well-known physical phenomena are unknown. He can't even write down the differential equations for functions of time and their derivatives that would produce such a strange response function.

I think that such a complicated response function is unlikely to follow from any physical mechanisms you may imagine at all. Note that the TSI is supposed to affect the climate for all values of the delay simultaneously. It sort of requires Nature to remember all the previous values somewhere, in a register, and then combine their effects. Realistic response functions may be approximated by functions with clear peaks near a single frequency – or several frequencies. But this function \(\tilde R(f)\) whose values for all \(f\) seem to matter seem immensely non-resonance-like, and virtually impossible to get from any underlying mechanism.

Maybe I could even prepare a rigorous proof that \(\tilde R(f)\) shown on the graph cannot result from a Fourier transform of any causal function \(R(t')\) that vanishes for \(t'\lt 0\). Maybe some extra conditions would be needed.

Again, I am ready to believe that the Sun has a significant impact on the Earth's climate. But it must be either something else than the TSI, or the effect must be such that all the wiggles shorter than 20 years or so must be universally suppressed. A model that takes these frequency components seriously and removes the unwanted prediction of a 11-year temperature cycle by hand is hugely contrived and the probability that it's zero or that it's a leading driver of the climate is nearly zero. There's no reason for response functions to have such sharp minima near the frequencies that are supposed to matter most and even if there were such minima, it's hugely unlikely that their corresponding frequency (which should only depend on the dynamics of the Earth) will happen to agree with the characteristic frequency of the solar processes (solar magnetic fields). The Earth's processes and the Sun's processes are uncorrelated.

So it's a piece of nicely done work which looks great but from a physics viewpoint, the required mechanisms seem impossible and from a statistical viewpoint, all the things presented as the virtues or the evidence are either tautologies – the Fourier transformation of a function back and forth – or they are vices that dramatically reduce the probability of the whole paradigm instead of increasing it.

If you ask about my guess, I am with Richard Lindzen and I do think that all the wiggles of the climate that are comparable to the changes in a decade or 20 years or to the changes by something modest of the order of 0.3 °C are due to the internal variability. These changes at these timescales are effectively "weather" which means that they're largely chaotic and you won't find any simple, demonstrably causal "external driver" that is responsible for all of them. Some people are obsessed with determinism so even if they abandon the dominantly CO2-driven theory of the climate, one which clearly disagrees with the empirical data, they still believe that there must be another equally clear driver of all the changes, by every tenth of a degree. But this isn't necessarily so. It's probably not the case. Many things just don't have deterministic causes and the weather isn't something that only affects the 1-day timescale. The significant effects of variable weather survive at much longer – and possibly all – timescales.

Only when the temperature changes become comparable to 8 °C, the difference between the interglacials' and ice ages' temperature, it's clear that most of the changes are externally driven, by the Milankovitch cycles rooted in astronomy. The evidence that the Milankovitch theory works, as clarified by Roe, is overwhelming. But in principle, all temperature changes that are substantially smaller than 8 °C may totally nicely be due to the "weather", some chaotic internal behavior of the Earth's atmosphere and the world ocean that admit no sharp predictive and no clearcut attribution.

P.S.: This blog post was suspended for a day because I've received some emotional e-mails from Jo Nova. She quickly modified her comments and said it was OK for this blog post to be here. She posted corrections of some misconceptions with my name in the title. I don't want to argue with her, she's a nice lady – most of the things I would reply are probably clear from the text above (repetition battles isn't something I will join) and from my general attitudes to the scientific method. I insist on my criticism and on the claim that I haven't attributed David any claims he hasn't made.

Just one thing to be sure: When I say that there are skeptics who are ready to endorse any statement as long as it sounds anti-alarmist, I am more than eager to enumerate 10 names as examples. To do so isn't a sign of bad manners. It's a sign of scientific integrity. Some of these people openly admit that they have this anti-alarmist agenda. It's a shame because honest science can't work like that. I am not one of them. There are some skeptics in the category who don't admit that but they still obey the condition...

Jo generally finds science – and the desire to say that an idea is wrong if it is wrong even if the author spent some time with it – too "cruel". Well, it's an adjective you may pick. But this "cruelty" is necessary for science's ability to be the only reliable way we know to converge closer to the truth about Nature. If Jo doesn't like these fundamental features of the scientific attitude to questions, finds them too "cruel" etc., maybe she shouldn't try to invade this "alien world". She may be harmed.

Quite generally, I do see that skeptics sometimes behave as unscientifically – and, indeed, dishonestly – as the alarmists. I am the last one who would hide it. It's unfortunate. But comments that some "scientists have spent 50 years on the [climate alarm theories]" is something that I know from a hysterical mail by Naomi Oreskes. It's disappointing if Jo would like to resemble Oreskes in this way. It's disappointing that I had to recall points 11, 12, 19, 26 of this index when I read her e-mails but that's how it simply was.


  1. In your first equation I think you should replace T on the right hand side with t.

  2. Thanks. When you were posting the comment, the error had been already fixed for 2 minutes. A reload would do it, too. ;-)

  3. Exactly. It's not hard to do this experiment. I won't bother because I am sure that if you model the characteristic behavior of the temperature noise well enough - if the noise has both similar magnitude of oscillations and a similar color to the noise (at least some rough dependence on the frequencies) we have observed, the condition will be obeyed.

  4. Your brain's metabolism must be extremely high in view of its extraordinary daily output. How many calories do you consume on average?

  5. It would be extremely easy to write 15 blog posts like that. You exaggerate, Luke. I don't want to go that high because no one would be reading things carefully enough.

    Still deciding whether to go to Prague, Klaus' party, tomorrow. I haven't been in Prague for many months.

  6. Your fast and insightful writing is almost irrelevant when compared with your unbreakable scientific integrity. Thank you so much Lubos.

  7. So Lubos you're basically saying that this, like other hypothesis, are allowing themselves to be fooled by chaos (or internal variation)? Chaotic systems, because they are stable and pattern-driven (until they're not), allow one to assume determinism in random patterns.

    I suspect we'll not get to a complete theory of the Earth's climate because of its chaotic nature despite being bound and coupled. We'll just have a multiple of actors and mechanisms that impact on the Earth's climate - some major like Milankovitch, some minor like CO2. Determining the interrelationships between them all seems a heroic if fruitless task.

  8. Give the guy credit for rigorously recovering his assumptions. This is a result that cannot be achieved by generalized climatology (Klimate Kaos!), SUSY, quantum gravitation, dark matter...macroeconomics, psychology, penology...anything where theory is allowed to define observation.

    Do you believe the experts or your own lying eyes?

    Phys. Rev. 105(4) 1413 (1957),
    This is wonderful! But...
    PNAS 14(7) 544 (1928),

    ...Cox saw it first, 30 years earlier, and was shouted down by theory that had to be correct. Theory was terrifically wrong.

  9. I am surprised that no one has mentioned http://www.realclimate.org/index.php/archives/2006/10/taking-cosmic-rays-for-a-spin/ and http://www.realclimate.org/index.php/archives/2007/03/cosmoclimatology-tired-old-arguments-in-new-clothes/ and all the developments thereafter.

  10. On the subject of symmetry maybe someone here can explain something to me. Neutrinos have a spin of 1/2 while anti-neutrinos have a spin of -1/2. This isn't a problem if neutrinos are mass-less. But how does this fit with neutrinos having mass?

  11. Congrats on 2nd place. Even if it was only for 1 hr.

    If you search for nhl5haze images you get nothing but pot plants. Weeds. So you are being beaten by a sitass pot head. That is gross

  12. That was my second concern. First was "What if this is just convoluted wiggle matching?" Third was "Uh-on. Log-log plots."

  13. I'd go to Prague if I could. And I'd wish that I was 30yrs younger. Do many of the people there (i.e. gals) speak angličtina? Maybe I'll send my son in 10yrs or so.

  14. You must be careful what the "spin" that they have means.

    Both neutrinos and antineutrinos formally have J=1/2 in the sense of the appropriate eigenvalue of J^2, from the internal angular momentum vector J.

    However, what may have a different sign is helicity, the component of the spin in the direction of the motion (momentum). Indeed, massive particles must have both signs allowed, by rotational symmetry. If neutrinos are massive, then they have to be Majorana particles or Dirac particles. Both of them have polarizations both with spin up and spin down, even at rest, so everything is OK.

    If neutrinos are Dirac particles, then there are extremely weakly interacting right-handed (right-spinning helicity) neutrinos which combine with the left-known handed ones (and similarly, with the right-handed antineutrinos) to particles fully analogous to electrons and positrons.

    If neutrinos are Majorana particles, then they are identical to antineutrinos. So this unified particle still has 2 polarizations with +1/2 and -1/2 at rests, like the electron, but it's the same one as its antiparticle. Only when it's moving, the helicity which may still have both signs effectively distinguishes the state of the particle to "neutrino" or "antineutrino" as well call the polarizations today.

  15. No one mentioned it because Evans' work is *not* cosmoclimatology, it's meant to be purely solar.

    Cosmoclimatology is otherwise being discussed on this blog often:


  16. I see! The username is a shortcut of

    Northern Lights #5 vs X Haze

    which are seeds of Marijuana, probably some breeding.


  17. Good morning.

    Check the time zone of his submissions. If it is LHC then he is bored during the shutdown and may have a special lab in the tunnels.

  18. In fact this brand is made for the LHC as it starts with "opposites collide on perfect fuzion".

    Then goes on to say it created a " permanent impression". I would say that is permanent brain damage.

    I would rather be hit with a collider beam than stinky smoke. On fact one person did have beam go through his head I think. He survives.


  19. A bumpkin from a provincial city should jump at the chance to visit the capital for its culture and refinement ;)

  20. You must have confused the two cities, Eugene. It's Pilsen, and not Prague, that is the 2015 European Capital of Culture!


  21. I wrote this in their comment section:
    Joanne, you write “Dividing the orange line in Figure 4 by the orange line in Figure 2, we arrive at the empirical transfer function shown in Figure 5″.

    Well, you do not. You can only estimate a transfer function from the CROSS-spectrum of output and input, divided by the spectrum of the input (both properly averaged to suppress noise). Dividing the output spectrum by the input spectrum gives you nonsense. It is easy to see why: if what you did would work, then you could obtain valid nonzero estimates of transfer functions for pairs of totally unrelated variables. And obviously that is impossible.

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  23. "But in principle, all temperature changes that are substantially smaller
    than 8 °C may totally nicely be due to the "weather", some chaotic
    internal behavior of the Earth's atmosphere and the world ocean that
    admit no sharp predictive and no clearcut attribution."

    Does that include the ~1500 year cycle described in Singer & Avery's 2008 book, Dr. Motl?

  24. Many things just don't have deterministic causes and the weather isn't something that only affects the 1-day timescale. The significant effects of variable weather survive at much longer – and possibly all – timescales.
    Well weather most definitely has deterministic causes but indeed affects the dynamics on many time scales.
    The deterministic causes are described by Navier Stokes equations and nobody doubts that the system has to obey N-S.
    Now there is a large number of results known about N-S.
    First of all the solutions of N-S live in an infinite dimensional Hilbert space of T,P and V fields.
    However it has been proven that 3D N-S admits a (weak) finite dimensional global attractor : ( see f.ex http://www.ima.umn.edu/preprints/Feb1995/1292.pdf )
    That means that any solution (e.g a given weather dynamics under known forcings) is restricted to a finite linear combination of spatial and temporal Fourier modes. The temporal Fourier modes govern the observed (pseudo) periodicities where some are suppressed and some are promoted.
    The spatial Fourier modes govern the observed spatial patterns (e.g ENSO, Gulf Stream etc) where it is also obvious that some patterns are preferred and others are suppressed.
    So weather and its averages (e.g climate) are not like "anything goes". They are on the contrary strictly deterministic and constrained to a well defined finite dimensional sub space of the Hilbert space.
    The problem with chaos is that forcings and boundary conditions don't stay strictly constant but vary.
    And it is known that chaotic systems have the property that attractor's topology may change, sometimes dramatically, even with an extremely small variation of forcings and/or boundary conditions.
    When all these facts are correctly taken in account, one comes necessarily to the conclusion that the weather behaviour on larger time scales (e.g climate) can only be a probabilistic theory much like QM.
    Indeed if the system is ergodic, time averages are equal to phase space averages so that knowing the attractor (what we don't. Yet.), one could predict quite accurately the probability distribution which is necessarily normalised over the attractor.
    The realization of some weather (climate) can of course not be predicted, only probabilities can.
    That's why I don't believe any theory like the one presented here which violates this basic result that only probabilities can be known for large dimensional chaotic systems.

  25. I appreciate the reproduction of 150 year old Physics (Response Functions and Fourier Transforms), but this all seems ridiculous to me... When one looks at the clear periodicity in the TSI and see's a corresponding lack of periodicity in the temperature data it should be a priori obvious that the climate is not responsive on length scales as short as 11 years. Do radio waves cause nuclear transitions. Do Gamma rays stimulate Phonons? This is well understood stuff, it just hasn't been applied to the climate.

    Tell him to filter out the short wavelength solar activity and try again. His time scales are obviously wrong... Perhaps there is something there if he does things correctly. Also tell him his response function probably will be imaginary since I'm sure the climate is lossy. Tell him any Condensed Matter text will explain the correct way to do things like this. This is Sophomore level material!

  26. Having read up to Part IV, I have found the David Evans proposal logical and compelling, and reasonably straight forward to understand.
    Ultimately all of the more detailed data and exact methods would have to be open and available to scrutiny which I understand is the plan.
    I did not read the separate paper on the optimal Fourier transform method, but guess that also has to be checked.
    I guess most of the people that are convinced CO2 is the main climate driver will not welcome this. The will demand to know what this 'Force X' is.

    Also the the plot figure 1 in post 1 shows e synchronicity between TSI and magnetic field changes only goes back to 1975 - I guess there are no other data sets that can be used to show a history match going back further?

    I was not completely convinced by the low pass filter or any mechanism that correlates with it. Maybe because I am not familiar with typical climate models that they mention that end up with this 5 year break frequency. Maybe there could be some clearer evidence for that? They did not really discuss the link of the low pass filter to the physical world... Other than saying "But a simple basic approach to heat accumulation tells us there must be a low pass filter, and it is at least compatible with the empirical transfer function."

    This could be covered in a future post.

    I am kind of surprised that nobody has looked at frequency domain analysis for climate modelling given how routine it is in engineering - not just electronics but also mechanical and acoustic engineering like vibration and dampening analysis, noise cancelling, etc...

    I'll be following this further. I'm curious Lubos why you didn't share all of your concerns with David Evans during the pre-release date? Had you done so he may have we could have corrected any misunderstandings or errors in what you have to say, while taking on board and amending his paper if it turns out any of your criticisms are justified.

  27. Lubos,
    For your info, the new paper just came out that quantifies amount of the available heat energy from the sun that reaches different parts of our planet's ground levels. The amount of energy in kJ is obtained from the difference between the minimum night time temperature and maximum temperature during daytime. And no, there are no obvious cycles and all can be explained by 3 molecules that influence temperatures on our planet, N2 and O2 that make 99% of our atmosphere and H20 that makes 70% of our surface. The paper is written by the experimental scientist who understands physicochemical properties of molecules and who understands how thermometer works. Paper can be found, free of charge pdf file, on www.l4patterns. com. Dr Darko Butina
    PS. I fully agree with your assessment of the current crises in Ukraine since I do understand Russia's history and their people

  28. Jennifer MarohasyJun 20, 2014, 2:11:00 AM

    Thanks Lubos for taking the time to read and respond to David Evan's ideas. What you are essentially saying is that his equations aren't robust/don't prove anything and certainly can't explaining the warming since 1970.

    But I disagree that weather/climate is chaotic beyond the large Milankovitch cycles, as you suggest. There are recurrent patterns, for example, in rainfall records, that relate to changes in sea surface temperatures and that these can be forecast using pattern analysis/artificial neural networks suggests there are physical mechanisms that need to be better understood?

    A recent article on this subject by myself and John Abbot here… http://www.sciencedirect.com/science/article/pii/S0169809513003141

  29. Dear Jennifer, thanks for your feedback - and sorry for the moderation queue for new commenters, a protection against spam etc.

    Yes, I am saying that the robustness or proving power is lacking. But I think I am saying something stronger than that. I actually think that a response function with such a sharp dip near a particular frequency cannot exist at all - its Fourier transform cannot be a function that vanishes for all negative time differences.

    One technicality is that David seems to overlook that the Fourier transform is a complex function in general. Maybe the graphs only show the real part, maybe only the absolute value. But whichever way it goes, if you Fourier-transform any function like that, you get a function that is positive and significant both for positive and negative t. That would imply the "influence into the past" as well as the future, a violation of causality. The only way to fix this problem is to add a delay that is significantly higher than the frequency at which the dip appeared (period 11 years), but at that moment, the model becomes both incredible (such huge delays are unlikely to operate).

    There are surely recurrent patterns. But one must carefully distinguish "recurrent patterns" and "periodic patterns". One must also distinguish "recurrent patterns" and "patterns showing the relationship between two particular quantities X,Y". I think that in the climate record, you find neither truly periodic sub-Milankovitch patterns, nor patterns that would show the impact of some external drivers.

    The real problem is that the correlation between the Sun's total output (in this case) and the climate is missing. David is essentially saying that this lack of correlation doesn't matter because the relationship may be given through a complicated response function which is fine-tuned to make all traces of the correlation disappear. One could speculate that such a relationship exists between any pair of quantities in the world so of course that the evidence is zero - the response function is just calculated from the data on both sides to fudge the elephant.

    But it's worse than that. The required response function we need here *cannot* result from *any* physical mechanism because it's not causal.

  30. Thanks for the clear explanation! Regarding the last paragraph, I've often thought the same, I wish some of the people studying LQG (and it's friends like CDT) could instead spend their time and brains into something more productive.

  31. Dear Lubos, I wish you would quote me exactly. Your paraphrasing has no resemblance to what I said. (Anyone who wants to see the "hysterical" or "emotional" words, can see all my emails to Lubos in full - http://jonova.s3.amazonaws.com/evans/emails-to-lubos-3.pdf). If you were not a good guy your PS note would have been a absolute gift for me to shred on my blog. But I have no desire to score points off you.
    I believe you owe me an apology. -- Jo

  32. Dear Jo, I won't join you in that cesspool. Please ask someone else, like David.

  33. Dr David Evans has "six degrees including a PhD from Stanford". He is also a "world authority on signal processing" and a bona fide "rocket scientist". [His own words]. Don't you know he is infallible and everyone else is completely wrong?

  34. A leading HVAC [heating, ventilation and air conditioning] engineer I know put it in very similar words. Very large bodies of air at different temperatures and humidity levels behave chaotically

  35. Bris Vegas, as you are from Australia judging by the tag, you should know that the term 'Rocket Scientist' is used in the Australian lexicon occasionally to describe a person who is highly technical. When David Evans used the term deliberately in a presentation it was obviously tongue in cheek. He was clearly not describing himself literally as a rocket scientist. Most sensible people 'got' that. It has only been climate alarmists, like the incredibly naive Anna Rose from the Australian Youth Climate Coalition who took it seriously and then got David to 'admit' that he hasn't actually worked on rockets! I guess you have now joined her ranks.

    As for infallibility - I have never seen David claim that anywhere and you couldn't assume that from his writings or actions. He is a most understated and humble person, so your ad hominem in your attempt to support Lubus might be loyal, but it isn't helpful or in any way accurate.

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