by Dr. Martin Hertzberg
As the saying goes:
“If all you have in your hand is a hammer, then everything looks like a nail”.
It is hopeless to expect that Hansen could possibly analyze data objectively – all he has in his head is “CO2 climate forcing” and everything else has to be “forced” into that ridiculous paradigm. It makes no difference to him that the predictions of his past half-baked computer models based on “CO2 climate forcing” were completely wrong.
It is not worth my time (or anyone else’s in my opinion) to try to critique the entire paper, but the final paragraph on his p. 11 stands our like a sore thumb. In it he states:
” Earth orbital (Milankovic) parameters have favored a cooling trend for the past several thousand years, which should be expected to start in the Northern Hemisphere (NH). For example, Earth is now closest to the sun in January, which favors warm winters and cool summers in the Northern Hemisphere.”
Those statements are typical of the misunderstanding in the popular literature of the Milankovic cycles. Since we are now further from the sun in the NH summer, he argues that the NH should get less solar insolation in the NH summer thus “favoring the growth of glaciers and ice-caps in the NH”. So why then we may ask are we now in an Interglacial Warming? What Hansen fails to realize is that when we are further from the Sun in NH summer we move more slowly in orbit, and are therefore exposed to the summer sun for a longer period of time.
From the graphs in the web-site http://individual.utoronto.ca/kalendis/seasons.htm , one can calculate that in 2010 the NH summer half of the earth’s orbit from the Spring Equinox to the fall Equinox lasts 186.1 days. The NH winter half of the orbit lasts 179.0 days. So the summer half gets 7.1 more days of solar insolation than the winter half. (Go to your calendar and count!)
Exposure time in this case is more significant that daily insolation caused by our further distance during the NH summer. And that is why we are in an Interglacial Warming and why Hansen is completely wrong in arguing that we should be “favoring the growth of glaciers and ice-caps in the Northern Hemisphere”.
Now some 10,000 years ago, because of the precession of the Equinoxes, summer and winter would have nearly flipped but with not much change in the earth’s orbital eccentricity. From the same web-site, in the year 8,000 BC, the NH summer half of the earth’s orbit lasted 178.5 days while the winter half lasted 186.6 days, so that the winter half exceeded the summer half by 8.1 days.
So 10,000 years ago the earth was further from the sun during NH winter and it spent a longer time on the winter half of the orbit, thus both effects re-enforced each other to give us a marked Glacial Cooling. (Actually the peak in that Glacial Cooling occurred several thousand years earlier than 8,000 BC.) Today, while we spend a longer time during the NH summer half of our orbit, we are further away in the summer, so the effects tend to cancel, but the longer time exposure is more important than the further distance.
The following discussion from my Chapter 12 of our recently published book “Slaying the Sky Dragon – Death of the Greenhouse Gas Theory” is a more general critique of the Hansen paper. Simply substitute “Hansen” for “Gore”.
The Legend of the Sky Dragon and Its Mythmakers
There is a simple way to tell the difference between propagandists and scientists. If scientists have a theory they search diligently for data that might actually contradict the theory so that they can fully test its validity or refine it. Propagandists, on the other hand, carefully select only the data that might agree with their theory and dutifully ignore any data that disagrees with it.
One of the best examples of the contrast between propagandists and scientists comes from the way the human caused global warming advocates handle the Vostok ice core data from Antarctica (6). The data span the last 420,000 years, and they show some four Glacial Coolings with average temperatures some 6 to 8 C below current values and five Interglacial Warming periods with temperatures some 2 to 4 C above current values. The last warming period in the data is the current one that started some 15,000 to 20,000 years ago. The data show a remarkably good correlation between long term variations in temperature and atmospheric CO2 concentrations. Atmospheric CO2 concentrations are at a minimum during the end of Glacial Coolings when temperatures are at a minimum. Atmospheric CO2 concentrations are at a maximum when temperatures are at a maximum at the end of Interglacial Warmings. Gore, in his movie and his book, “An Inconvenient Truth”, shows the Vostok data, and uses it to argue that the data prove that high atmospheric CO2 concentrations cause global warming.
Is that an objective evaluation of the Vostok data? Let’s look at what Gore failed to mention. First, the correlation between temperature and CO2 has been going on for about half a million years, long before any significant human production of CO2, which began only about 150 years ago. Thus, it is reasonable to argue that the current increase in CO2 during our current Interglacial Warming, which has been going on for the last 15,000 – 20,000 years, is merely the continuation of a natural process that has nothing whatever to do with human activity. Gore also fails to ask the most logical question: where did all that CO2 come from during those past warming periods when the human production of CO2 was virtually nonexistent? The answer is apparent to knowledgeable scientists: from the same place that the current increase is coming from, from the oceans. The amount of CO2 dissolved in the oceans is some 50 times greater than the amount in the atmosphere. As oceans warm for whatever reason, some of their dissolved CO2 is emitted into the atmosphere, just as your soda pop goes flat and loses its dissolved CO2 as it warms to room temperature even as you pour it into the warmer glass. As oceans cool, CO2 from the atmosphere dissolves back into the oceans, just as soda pop is made by injecting CO2 into cold water.
But the real “clincher” that separates the scientists from the propagandists comes from the most significant fact that Gore fails to mention. The same Vostok data show that changes in temperature always precede the changes in atmospheric CO2 by about 500-1500 years.
The temperature increases or decreases come first, and it is only after 500-1500 years that the CO2 follows. Fig 3 shows the data from the termination of the last Glacial Cooling (Major Glaciation) that ended some 15,000 – 20,000 years ago through the current Interglacial Warming of today. The four instances where the temperature changes precede the CO2 curve are clearly shown. All the Vostok data going back some 420,000 years show exactly the same behavior. Any objective scientist looking at that data would conclude that it is the warming that is causing the CO2 increases, not the other way around as Gore claimed. I am indebted to Guy Leblanc Smith (guy.lbs@rockknowledge.com.au) for granting permission to use Fig. 3 as it was published in Viv Forbes’ web-site www.carbon-sense.com .
It is even more revealing to see how the advocates of the human-caused global warming theory handle this “clincher” of the argument. It is generally agreed that the Vostok cycles of Glacial Coolings and Interglacial Warmings are driven by changes in the parameters of the Earth’s orbital motion about the Sun and its orientation with respect to that orbit; namely, changes in the ellipticity of its orbit, changes in its obliquity (tilt relative to its orbital plane), and the precession of its axis of rotation. These changes are referred to as the Milankovitch cycles, and even the human caused global warming advocates agree that those cycles “trigger” the temperature variations. But the human caused global warming advocates present the following ad hoc contrivance to justify their greenhouse effect theory.
The Milankovitch cycles, they say, are “weak” forcings that start the process of Interglacial Warming, but once the oceans begin to release some of their CO2 after 500-1500 years, then the “strong” forcing of “greenhouse warming” takes over to accelerate the warming. That argument is the best example of how propagandists carefully select data that agrees with their theory as they dutifully ignore data that disagrees with it. One need not go any further than to the next Glacial Cooling to expose that fraudulent argument for the artificial contrivance that it really is. Pray tell us then, we slayers of the Sky Dragon ask, what causes the next Glacial Cooling? How can it possibly begin when the CO2 concentration, their “strong” forcing, is at its maximum? How can the “weak” Milankovitch cooling effect possibly overcome that “strong” forcing of the greenhouse effect heating when the CO2 concentration is still at its maximum value at the peak of the Interglacial Warming? The global warmers thus find themselves stuck way out on a limb with that contrived argument. They are stuck there in an everlasting Glacial Warming, with no way to begin the next Glacial Cooling that the data show.
But one has to be sorry for Gore and his friends, for after all, they are in the global warming business. Global cooling is clearly someone else’s job!”
I can think of nothing more inappropriate and insulting to Milankovic than having Hansen speak at a Symposium in his honor.
===============================================================
Published originally at SPPI
Reference: Jan. 18, 2011: Paleoclimate Implications for Human-Made Climate Change: Draft paper for Milankovic volume. James Hansen
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Milankovic Cycles and Climate Change
Is it distance from the sun, or length of summer?
By Ed Caryl
A draft paper by Dr. James Hansen and Dr. Makiko Sato triggered a rebuttal by Dr. Martin Hertzberg on WUWT. The Hansen paper made a claim that weaker insolation in the Northern Hemisphere (NH) due to distance from the sun in NH winter should lead to cooling, but that this is offset by increasing CO2.
The Dr. Hertzeberg rebuttal claimed that the warming was due to the longer length of summer in the NH. Both are wrong! Both are victims of Confirmation Bias, seeing only data that confirms their beliefs.
http://notrickszone.com/2011/01/25/milankovic-cycles-and-climate-change/
Adam R,
To be honest about it I didn’t read the article, only the comments. So how about telliing us in your own words what the problem is, instead of making tamino your crutch.
Better yet, submit your own article. Show us the way you believe the real world works, instead of criticizing Anthony for whatever it is that you don’t like.
I read Hertzberg here, and Tamino, and Tamino seemed more competent to me. Of course I could be wrong, as I don’t know so much, but Hertzberg seemed to be more of a handwaving argument, while Tamino seems to be saying, “Do the maths, and this is what you get”. When talking about quantitative things I prefer maths to words.
Milankovich began his work in 1911 and published “Mathematical Climatology and the Astronomical theory of Climatic Change” in 1930, now accepted as a defintive work on the causes of ice ages. All this without the assistance of computers nor the data from ice cores. What an achievement! ‘When asked if he was planning another major work, Milankovich, somewhat weary, replied: ” Theories of the magnitude of the one I have completed do not grow on trees.” ‘ (John L Daly The Greenhouse Trap). Perhaps AGW proponents should take a leaf from Milankovich’s book
Tamino wins. Hands down. Sorry. Hertzberg doesn’t do the analysis appropriately and it shows.
John Brookes says:
January 25, 2011 at 8:25 pm
“I read Hertzberg here, and Tamino, and Tamino seemed more competent to me.”
I wouldn’t say more competent, merely more expansive. I will grant you that Hertzberg has only made an assertion without backing it up. At least, not here. But, I do not see that Tamino has proven anything. His math says the same thing mine said: to first order, disregarding other variables, total input energy is the same. Then, he asserted that the peak temperature for perihelion summer is greater than for aphelion summer*, and furthermore, this proves that it is more propitious for glacial melt.
But, it does nothing of the kind, as I explained at January 25, 2011 at 7:29 pm. When both sides present incomplete arguments, you do not have to choose sides. You should hold out for more information. I decided that the question is quite complicated, and deserves more thorough analysis than provided by either Hertzberg or Tamino. I think the most important question is, how does the rate of melt depend on temperature? If it accelerates rapidly with increasing temp, then Hansen/Tamino may have the upper hand. If, however, it is roughly flat beyond some threshold, then Hertzberg is more likely correct.
*likely enough, but I’d like to see proof, taking into account the thermal dynamics – I withdrew my earlier claim at January 25, 2011 at 4:01 pm because I no longer believed it “likely”, not because I thought the opposite was necessarily true, and I did not have enough information or motivation to pursue it further.
Robert says:
January 25, 2011 at 9:16 pm
“Hertzberg doesn’t do the analysis appropriately and it shows.”
Neither does Tamino.
Looks to me that this case is closed.
Dr. Hertzberg , thanks for introducing me to some facts I didn’t know about the variability in the length of seasons that was fascinating.
Thanks to Dr. Tamino for pointing out the incorrect conclusions that the variability of the seasons led DR. Hertzberg to.
Thanks Anthony for letting it all happen in front of our eyes , good stuff. Presumably Dr. Hertzberg will close off the debate with an appropriate posting in the not too distant future rather than just quietly remove the paper without comment as seems to be the way of other less democratic sites.
Keith Battye says:
January 25, 2011 at 10:58 pm
You Tamino myrmidons are really out in force tonight, aren’t you? A complete lack of critical thinking skills. Just sad.
Bart says:
January 25, 2011 at 9:55 pm
“When both sides present incomplete arguments, you do not have to choose sides. You should hold out for more information.”
But that is not an accurate characterisation of the position. All arguments concerning such matters are incomplete. What is more important is which argument is false: and the laurel for that achievement falls on Hertzberg’s head.
@-Bart says: You appear to have missed my main points to Ferdinand and Joel:
“…
B) the emissions data contains cycles which do not appear in the measurements of CO2, which is impossible if the emissions data are reasonably reliable, and if they are not, then even the superficial similarity between the curves is open to question”
No, I saw that, but the fact that emissions are twice the measured atmospheric rise so that it is logicaly inescapable that they are a component of any measured rise is conclusive IMO.
The fact that the variations in emissions are also below the annual variation in bio-productivity and sinks also means as far as I can see that it is inevitable that emission variations are swamped in the measured rise by the interannual variations.
Back on the Milankovic cycle dispute;
The ‘standard model’ attributes the influence on the climate to the intensity of the insolation at high Northern latitudes, conventionally 65N, during summer. The duration of the seasons is not considered to be much of a factor. This based on observations and the hypothesis that the summer melt is crucial, while winter temperatures just modulate ice accumulation rates.
This is NOT a popular misconception of the Milankovic theory, its is the shared version in the scientific community and I do not see that Hansen is contradicting that.
Hertzberg is suggesting an ALTERNATIVE hypothesis about the influence of the Milankovic cycles, that the duration of the seasons is a factor. I dont see any observational or physical processes put forward that supports his contention.
Slioch says:
January 26, 2011 at 1:33 am
“What is more important is which argument is false: and the laurel for that achievement falls on Hertzberg’s head.”
That has not been demonstrated. If you do not understand, review my previous posts on the matter.
izen says:
January 26, 2011 at 2:51 am
“No, I saw that, but the fact that emissions are twice the measured atmospheric rise so that it is logicaly inescapable that they are a component of any measured rise is conclusive IMO.”
Sure, they are “a component”. They must be. Just like the emissions variation, all inputs must leave their mark in the output. But, they are a small one, if the CO2 feedbacks are robust. And, they must be so, because otherwise, the CO2 measurements would exhibit strong random walk-like behavior. This, again, is what I mean by “infancy”. The climate gurus have constructed a first order model which produces the outputs they want, but they have not taken consideration of the secondary characteristics such a system must produce in the real, noisy and complex world.
“…emission variations are swamped in the measured rise by the interannual variations.”
No. I demonstrated that the proportions of the coefficients were high enough to be observable above the noise floor, if the emissions were the major driver.
“The duration of the seasons is not considered to be much of a factor… This is NOT a popular misconception of the Milankovic theory, its is the shared version in the scientific community and I do not see that Hansen is contradicting that.”
When you don’t know, always assert that you have the backing of 9_% of authorities. Guys like you would be lost if you imagined yourself to be cut off from the herd. This is known as ad verecundiam argumentation, izen. It is one of the fundamental, classical logical fallacies.
Milankovic cycles are not in any way, shape or form cut and dried and laid to rest. Again, you have the problem that there is no closed loop, no control experiment you can do to replicate the condition. But, you need to at least dig deeper than Tamino’s shallow assertions. Tell me how temperatures at 65N will vary with insolation, and how melt rates will vary with temperatures, and then we can at least form a more solid hypothesis.
“…emission variations are swamped in the measured rise by the interannual variations.”
On this, in particular, in interannual variations are at a completely different frequency. They cannot “swamp” anything at another frequency. What matters is the noise floor. Look for that phrase in the thread where I discuss why it is important.
“No, I saw that, but the fact that emissions are twice the measured atmospheric rise so that it is logicaly inescapable that they are a component of any measured rise is conclusive IMO.”
That is very bad logic, BTW. Even if atmospheric concentrations were falling, the emissions would have to be “a component” of the total. The question is, how much does it add, after all sinks and sources are accounted for? That we do not yet have a full accounting is evidenced by the data.
“I dont see any observational or physical processes put forward that supports his contention.”
It should be self-evident that both temperature and duration of its application affect quantity of glacial melt. The question is, which dominates? Hertzberg asserted duration. Tamino did some math to say they were equal, then bizarrely proceeded to assert that temperature dominates. And, you guys lapped it up like he had succeeded in some ingenious proof. I guess you were dazzled by the integrals. Note to Hertzberg: next time, throw in some integrals.
bart says:
That’s not really a fair summary. It ignores the fact that Hertzberg has no evidence whatsoever to support his hypothesis that the duration dominates and yet he still publishes a grandiose post claiming that Hansen is wrong and going off into talking about propagandists (which is about as good an example of projection as you are ever going to find).
Not only does Hertzberg’s view go against all of the conventional wisdom, it goes against the climatic evidence from the ice core (or other paleoclimate) records. And, Hertzberg makes some bizarre statements like saying that the fact that we are currently closest to the sun during the Northern hemisphere winter and it is during an interglacial supports his hypothesis when in fact the cycle was close to 180 deg opposite to this at the time when we emerged from the glacial period into the interglacial…and reached the peak warmth of the interglacial, especially for the Northern Hemisphere, at least until very recent anthropogenic times.
I assume Hertzberg will come here either to offer some real evidence to back up his assertions that the conventional understanding is wrong or he will profusely apologize to both Hansen and readers of WUWT. That would be the honorable thing to do.
I feel confident now in reasserting a modified version of what I stated at
January 25, 2011 at 1:18 pm. If the dominant thermal time constant (assuming there is one, or constants if there are perhaps several significant ones) is on the order of days, which it almost surely is, then I believe it is likely that Hansen/Tamino are wrong, and Hertzberg is right. This comes about because the thermal time constant acts as a low pass filter which does not so much affect the slowly changing insolation around aphelion, but beats down the faster changing peak at perihelion.
My analysis is admittedly coarse, based on my knowledge of all the factors involved. It is perilous to project the behavior of complex systems based on simple models without direct observations to confirm it. So, I am not proclaiming my hypothesis to be “truth” absent that. Nor am I going to seek some ridiculous measure of assurance based on whether some other “authority” of unexamined qualifications agrees. The reader would be well advised to be wary of people who proclaim 100% assurance based on such criteria.
I am merely making a truthful observation without assertion based on known facts: thermal processes are typically low pass, and the insolation at perihelion progresses more rapidly, hence heating will be attenuated by the low pass response. Were it not, the math presented by both me and by Tamino argues that the energy input, and hence the glacial melt, would be approximately equal overall. Any thinking person who can process information logically would conclude that Tamino is out on a limb.
And, now I would like to request that all the lackeys who demanded a retraction from Anthony demonstrate consistency in their actions, and turn their rhetorical guns on Tamino to respond in kind.
Oh, you can’t, because he won’t let your adverse comment appear on his site, you say? Well, well… what does THAT tell you?
@-Bart says:
“his is known as ad verecundiam argumentation, izen. It is one of the fundamental, classical logical fallacies. Milankovic cycles are not in any way, shape or form cut and dried and laid to rest. Again, you have the problem that there is no closed loop, no control experiment you can do to replicate the condition.”
You are misconstruing my argument here, its not from authority.
As always what Nature does comes first. (and last)
The OBSERVATIONS indicate that glacial cycles closely match Milankovic cycles. The timing, magnitude and rate of ENERGY delivery (not temperature) at 65N is the largest variable that most closely correlates with the observed climate behavior. When I then give the ‘standard model’ explanation for that observation I am NOT claiming that the standard model is correct because some overriding percentage of scientists accept it. I am showing that what Hansen has referenced with the short paragraph that caused Heretzberg to characterize him as a propagandist is not ‘a popular misconception’ but the explanation of observations that is in current use.
Given the observations, the description of the system, the usual procedure is to look for physical processes to provide an explanation of the systems observed behavior. The present explanation MAY be replaced by a better one. But I see no evidence that Hertzberg attempts to provide one. He just seems to disparage Hansen for using the current explanation.
Re; A-CO2 emissions variations swamped by seasonal cycle. –
“On this, in particular, in inter-annual variations are at a completely different frequency. They cannot “swamp” anything at another frequency. ”
Okay I take your point, it was badly expressed on my part. Because the magnitude of seasonal variations is greater than changes in A-CO2 emission rates I would not expect the system to show a close correlation between input and output for those variations.
I compare this to what is admittedly a MUCH more complex system, but it gives me a ‘metaphor’ at least for how such a system might behave.
If someone has a increased intake of calories then I would expect that they would put on weight faster and to a level not seem before . There may be other metabolic factors that link weight to cal. intake, but while these may cause small variations I would expect to see a first order correlation between calorie intake (CO2 emissions) and weight. (CO2 levels) I would not expect minor variations in cal. intake to show up in matching variations in weight. The observed small scale variability shows there are storage/dissipation processes that can impose variation, or suppress it.
It tells me you fear to post any “adverse comment” at Tamino’s blog because you know it would be destroyed, and are creating a straw martyr to strut for the admiration of the WUWT choir.
Go ahead, Bart: post your stunning “adverse comments” at Open Mind, and let’s see how they fare. I doubt you have the huevos, but perhaps you will surprise me.
Adam R.,
I have posted – or tried to – on tamino’s blog quite a few times.
Not a single comment ever saw the light of day. They were all censored out.
The problem is with tamino, not with scientific skeptics.
It is tamino who doesn’t have the balls to post opposing points of view.
izen says:
January 26, 2011 at 6:20 pm
“Because the magnitude of seasonal variations is greater than changes in A-CO2 emission rates I would not expect the system to show a close correlation between input and output for those variations.”
I am telling you the way natural systems work, izen. This is non-negotiable. It is known. The input must show up in the output. If there were infinite precision, then it would not matter a wit how large the seasonal variations were. I would always be able to separate out other cycles which occur in the given interval, or are aliased into it. But, there are random errors or “noise” in the data. The only question is whether the spikes I noted are large enough that their effect should be discernible in the measurements will above the noise floor. I have answered that question: they are.
“The observed small scale variability shows there are storage/dissipation processes that can impose variation, or suppress it.”
Then, it would have to be an exceedingly low bandwidth system, because there are large cycles are in the range of 10-20 years. Natural systems rarely (probably never) exhibit roll-off of more than -12 dB/octave, so you’d need to start rolling off at least two octaves lower than that. At the very least, this is not consistent with responses seen in the measurements to events such as the Mt. Pinatubo eruption.
Thus, the only way out is the one I myself pointed out to Ferdinand, and he eventually adopted after strenuous objections: the cycles observed in the emissions data must be spurious. I agree, they could be. But, that calls into question the superficial similarity of the integrated emissions with the measurement data, as I explained in excruciating detail in that thread.
If you want to understand the issues better, I suggest you study frequency domain analysis and estimation of power spectral densities. I mention this because your talk of “correlation” suggests to me that, like so many others, think that you can analyze cyclical systems using statistical techniques intended for simple polynomials whose measurements are corrupted by white noise. Those are the wrong tools, and that is precisely the kind of thing I was talking about at January 25, 2011 at 12:45 pm when I said “in something rather more rigorous and mature, and sorely needing to be applied in that field”.
Adam R. says:
January 26, 2011 at 8:05 pm
I have little doubt your statement has been greeted by a merry round of guffaws and derisive tittering by many others besides Smokey. Sorry (not really) to break the news to you that your heroes have feet of clay.
For others who have been following along: I have performed more numerical experiments. There is little room for doubt that Tamino is wrong. The only quibble possible is that the effect I have noted is quite small for such small eccentricity, and might not rise to significance in a even very long time (though it still tips the balance in Hertzberg’s favor, because Tamino’s idea that all that matters is the temperature on midsummer’s day is weightless). I find myself increasingly disposed to the POV of this fellow, noted by R. de Haan at January 25, 2011 at 7:36 pm that other variations, such as in eccentricity and obliquity, have greater impact.
Bart says:
January 26, 2011 at 11:02 pm
“I am telling you the way natural systems work, izen. This is non-negotiable. It is known. The input must show up in the output.
…If you want to understand the issues better, I suggest you study frequency domain analysis and estimation of power spectral densities. I mention this because your talk of “correlation” suggests to me that, like so many others, think that you can analyze cyclical systems using statistical techniques intended for simple polynomials whose measurements are corrupted by white noise. Those are the wrong tools, and that is precisely the kind of thing I was talking about at January 25, 2011 at 12:45 pm when I said “in something rather more rigorous and mature, and sorely needing to be applied in that field”.”
==========
I don’t doubt you have better math chops than me when it comes to analysis, but I would doubt your first assertion that ‘the input must show up in the output at all time domains and amplitudes in natural systems.
I can think of several biological systems where that is certainly not true and it is quite possible for a varying input to generate a smooth trend with its own independent inherent variations. The fact that the small variations in input do not show up in the output does not refute the contribution of that input to an observed trend. True such biological systems are much more complex than the A-CO2 => atmosphere, ocean and biosphere system under discussion here, but the presence of a biological component in this system give me some grounds for the suspicion that you cannot dismiss the causal link between the emissions and observed rise in this system.
Certainly not on the basis of the lack of detectability of variation in the observed atmospheric CO2 level that matches the variation in the emissions.
The attribution of maximum summer insolation at 65N during summer to glacial age warming is not arbitrary. It is the result of observation.
What causal chain links those two factors is open to question. But if you have an alternative causal parameter that you can derive from the Milankovic cycles and a physical process that explanians that link, then by all means provide it.
Bart says:
I don’t think people on this site are too impressed by “numerical experiments”. The numerical experiments are only as good as the model on which they are based. Your model is confused in that you think that warming always has a certain effect. In fact, warming during the winter season has negligible effect on the melting of the ice sheet and, in fact, tends to be accompanied by higher precipitation, which favors ice sheet growth. This is why your theoretical musings produce predictions that do not correspond to what is seen in the real world and tamino’s and Hansen’s do.
izen says:
January 27, 2011 at 8:54 am
“I would doubt your first assertion that ‘the input must show up in the output at all time domains and amplitudes in natural systems.”
I did not say amplitudes. You are putting your own words in my mouth. Yes, as I explained, every system has a frequency response which modulates the amplitudes as a function of frequency. If there are significant nonlinearities in the system, you also get harmonics of the input fundamental frequencies. But, such filtering must also obey certain laws in a causal system, to wit, as I explained, the lower the frequency you want to attenuate, the longer the lag between input and output.
“The attribution of maximum summer insolation at 65N during summer to glacial age warming is not arbitrary. It is the result of observation.”
The devil is in the details, buckaroo. Scientific investigation begins with observation, then hypothesis, then experimental confirmation. In this instance, as in the ice core samples of Co2, there is no avenue for conclusive experimental confirmation, and the hypothesis can not be proven given the available data. The math shows the effects of precession of the equinoxes are equal to first order.
“But if you have an alternative causal parameter that you can derive from the Milankovic cycles and a physical process that explanians that link, then by all means provide it.”
I gave you one. The smoothing of temperature due to thermal time constants means the peak temperature for perihelion is less than it otherwise would be. The entire waveform is attenuated and spread out. It is the spreading out that does it, because otherwise, the integrated temperature would still be the same over the orbit. But, there is a threshold of 0 degC below which ice no longer melts, so the spread out waveform translated into rate of melt gets chopped, and the integration is reduced relative to the summer aphelion case, so you get less melt. It actually is faster than I thought last night, though I still think the link I provided’s reference to other changes in orbital variable are probably more powerful. And, that’s another explanation for the different rates of melt: other processes, like the changes in orbital eccentricity and obliquity of the rotation axis.
Funny how you go on demanding I provide you with alternative explanations after I already have, but you are content with an airy dismissal of my observation that CO2 emissions spectra are not observable in measurement spectra.