Does CO2 Drive the Earth’s Climate System? Comments on the Latest NASA GISS Paper
by Dr. Roy Spencer
There was a very clever paper published in Science this past week by Lacis, Schmidt, Rind, and Ruedy that uses the GISS climate model (ModelE) in an attempt to prove that carbon dioxide is the main driver of the climate system.
This paper admits that its goal is to counter the oft-quoted claim that water vapor is the main greenhouse gas in our atmosphere. (They provide a 1991 Lindzen reference as an example of that claim).
Through a series of computations and arguments, the authors claim that is actually the CO2, not water vapor, that sustains the warmth of our climate system.
I suspect this paper will result in as many opinions in the skeptic community as there are skeptics giving opinions. But unless one is very careful in reading this paper and knows exactly what the authors are talking about, it is easy to get distracted by superfluous details and miss the main point.
For instance, their table comparing the atmospheres of the Earth, Venus, and Mars does nothing to refute the importance of water vapor to the Earth’s average temperature. While they show that the atmosphere of Mars is very thin, they fail to point out the Martian atmosphere actually has more CO2 than our atmosphere does.
I do not have a problem with the authors’ calculations or their climate model experiment per se. There is not much new here, and their model run produces about what I would expect. It is an interesting exercise that has value by itself.
It is instead their line of reasoning I object to — what they claim their model results mean in terms of causation– in their obvious attempt to relegate the role of water vapor in the atmosphere to that of a passive component that merely responds to the warming effect of CO2…the real driver (they claim) of the climate system.
OUR ASSUMPTIONS DETERMINE OUR CONCLUSIONS
From what I can tell reading the paper, their claim is that, since our primary greenhouse gas water vapor (and clouds, which constitute a portion of the greenhouse effect) respond quickly to temperature change, vapor and clouds should only be considered “feedbacks” upon temperature change — not “forcings” that cause the average surface temperature of the atmosphere to be what it is in the first place.
Though not obvious, this claim is central to the tenet of the paper, and is an example of the cause-versus-effect issue I repeatedly refer to in the past when discussing some of the most fundamental errors made in the scientific ‘consensus’ on climate change.
It is a subtle attempt to remove water vapor from the discussion of “control” over the climate system — by definition. Only those of us who know enough of the details of forcing-feedback theory within the context of climate change theory will likely realize this, through.
Just because water vapor responds quickly to temperature change does not mean that there are no long-term water vapor changes (or cloud changes) — not due to temperature — that cause climate change. Asserting so is a non sequitur, and just leads to circular reasoning.
I am not claiming the authors are being deceptive. I think I understand why so many scientists go down this path of reasoning. They view the climate system as a self-contained, self-controlled complex of physically intertwined processes that would forever remain unchanged until some “external” influence (forcing) enters the picture and alters the rules by which the climate system operates.
Of course, increasing CO2 is the currently fashionable forcing in this climatological worldview.
But I cannot overemphasize the central important of this paradigm (or construct) of climate change theory to the eventual conclusions the climate researcher will inevitably make.
If one assumes from the outset that the climate system can only vary through changes imposed external to the normal operation of the climate system, one then removes natural, internal climate cycles from the list of potential causes of global warming. And natural changes in water vapor (or more likely, clouds) are one potential source of internally-driven change. There are influences on cloud and water vapor other than temperature which in turn help to determine the average temperature state of the climate system.
After assuming clouds and water vapor are no more than feedbacks upon temperature, the Lacis et al. paper then uses a climate model experiment to ‘prove’ their paradigm that CO2 drives climate — by forcing the model with a CO2 change, resulting in a large temperature response!
Well, DUH. If they had forced the model with a water vapor change, it would have done the same thing. Or a cloud change. But they had already assumed water vapor and clouds cannot be climate drivers.
Specifically, they ran a climate model experiment in which they instantaneously removed all of the atmospheric greenhouse gases except water vapor, and they got rapid cooling “plunging the climate into an icebound Earth state”. The result after 7 years of model integration time is shown in the next image.
Such a result is not unexpected for the GISS model. But while this is indeed an interesting theoretical exercise, we must be very careful about what we deduce from it about the central question we are ultimately interested in: “How much will the climate system warm from humanity adding carbon dioxide to it?” We can’t lose sight of why we are discussing all of this in the first place.
As I have already pointed out, the authors have predetermined what they would find. They assert water vapor (as well as cloud cover) is a passive follower of a climate system driven by CO2. They run a model experiment that then “proves” what they already assumed at the outset.
But we also need to recognize that their experiment is misleading in other ways, too.
First, the instantaneous removal of 100% of the greenhouse gases in the atmosphere except for water vapor causes about 8 times the radiative forcing (over 30 Watts per sq. meter) as does a 100% increase in CO2 (2XCO2, causing less than 4 Watts per sq. meter), something that will not occur until late this century — if ever.
This is the so-called ‘logarithmic effect’…adding more and more CO2 has a progressively weaker radiative forcing response.
Currently, we are about 40% of the way to that doubling. Thus, their experiment involves 20 times (!) the radiative forcing we are now experiencing (theoretically, at least) from over a century of carbon dioxide emissions.
So are we to assume that this dramatic theoretical example should influence our views of the causes and future path of global warming, when their no-CO2 experiment involves ~20 times the radiative forcing of what has occurred to date from adding more CO2 to the atmosphere?
Furthermore, the cloud feedbacks in their climate model are positive, which further amplifies the model’s temperature response to forcing. As readers here are aware, our research suggests that cloud feedbacks in the real climate system might be so strongly negative that they could more than negate any positive water vapor feedback.
In fact, this is where the authors have made a logical stumble. Everyone agrees that the net effect of clouds is to cool the climate system on average. But the climate models suggest that the cloud feedback response to the addition of CO2 to our current climate system will be just the opposite, with cloud changes acting to amplify the warming.
What the authors didn’t realize is that when they decided to relegate the role of clouds in the average state of the climate system to one of “feedback”, their model’s positive cloud feedback actually contradicts the known negative “feedback” effect of clouds on the climate’s normal state.
Oops.
(In retrospect, I suppose they could claim that cloud feedbacks switched from negative at the low temperatures of an icebound Earth, to being positive at the higher temperatures of the real climate system. But that might mess up Jim Hansen’s claim of strongly positive feedbacks during the Ice Ages).
CONCLUSION
Taken together, the series of computations and claims made by Lacis et al. might lead the casual reader to think, “Wow, carbon dioxide really does have a strong effect on the Earth’s climate system!” And, in my view, it does. But the paper really tells us nothing new about (1) how much warming we can expect from adding more CO2 to the atmosphere, or (2) how much of recent warming was caused by CO2.
The paper implies that it presents new understanding, but all it does is get more explicit about the conceptual hoops one must jump through in order to claim that CO2 is the main driver of the climate system. From that standpoint alone, I find the paper quite revealing.
Unfortunately, what I present here is just a blog posting. It would take another peer-reviewed paper that follows an alternative path, to effectively counter the Lacis paper, and show that it merely concludes what it assumes at the outset. I am only outlining here what I see as the main issues.
Of course, the chance of editors at Science allowing such a response paper to get published is virtually zero. The editors at Science choose which scientists will be asked to provide peer review, and they already know who they can count on to reject a skeptic’s paper.
Many of us have already been there, done that.
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George E. Smith (October 22, 2010 at 9:16 am ) referring to Michael Hammer (Oct 22, 2010 at 12.13 am) accuses him of being wrong about total solar irradiance because he used a value of 340W/ m^2 at the top of the atmosphere rather than George’s figure of 1366 W/ m^2. He says that there is no justification for dividing the higher number by 4 and cannot understand why people do it (“I don’t know why climatists insist on dividing the TSI by 4, as if the weather and climate responds to the average energy impinging on the surface. Try to get a desert surface temperature of +60 to + 90 degrees C, with 340 W/m^2 impinging on it continuously, 24/7”).
Oh really?
Whilst he is technically correct that the TSI (as measured empirically by satellite instrumentation) is 1366W/ m^2 and not 340W/ m^2, the reason why Michael used ¼ of the TSI figure is because he was averaging the energy flow (i) over the whole of the globe rather than just the illuminated hemisphere facing the Sun (so divide by 2); and (ii) over the whole of the hemispherical surface, which (by school geometry) is twice the earth’s cross-sectional area presented to the Sun (so divide by 2 again). It’s true that Michael should not have claimed that the 340W/ m^2 number is the TSI but nevertheless he has the right number to get the right conclusion because, when employed along with Stefan’s Law to calculate the average temperature of a ‘black body’ Earth without any atmosphere, the result is indeed around 5 or 6 degC.
Of course with a TSI of 1366W/ m^2, the Solar Insulation at or near the equator at 12noon on a cloudless day would indeed be close to 1366W/m^2 because (a) that particular square meter is normal to the Sun’s rays; and (b) it is midday not midnight. So there’s no conflict there either.
Actually there’s a simpler way of calculating that the average temperature of ‘black body’ Earth is 6degC without even using the TSI. You just divide the Sun’s diameter (1,392,000,000m) by four times the Earth-to-Sun distance (149,598,000,000m). Take the square root of the result and multiply it by the Sun’s surface temperature (5800K). Try it!
David Hoffer (10:43pm) and anna v. (12:00am) have adequately exposed the aphysical nonsense that Lacis et al. espouse as “known physics.” I only add the observation that their appeal to a hand-waving distinction between radiative forcing and “feedback” reveals a total ignorance of how feedback control systems operate. Such systems sense the output (without putting any load on it) and via an independently powered feedback loop return a facsimile of the output for algebraic addition to the input. The system itself is physically immutable.
Nothing in the planetary climate system acts that way to affect the input solar irradiance or the responses that it produces. What we have instead is an adaptive sytem, which, through phase changes of water, alters its physical response characteristics to the immutable forcing provided by solar irradiance. That results in different temperatures being observed as a state variable, depending on how much of the atmospheric H2O is in the condensed state of water droplets or ice crystals found in clouds.
CO2 has no demonstrable effect upon such phase changes. Furthermore, changes in its concentration invariably LAG temperature changes on all frequency scales that show any significant coherence between the two time-series. One has to be blind to the basic requirements of causal system behavior to claim that, in the geophysical setting, CO2 acts a “control knob.” It may have varied concommitantly with temperature changes in the past, but it never forced those changes. Man-made changes in present-day concentrations have produces no detectible changes in temperature that are coherent with the recent CO2 record. Such are the basic physical facts as OBSERVED empirically, instead of being IMPUTED by programming models.
Jim D says:
October 23, 2010 at 8:10 am
First of all contrails are not produced by the flow of air over an aeroplane’s wing as you seem to suppose. Contrails are the result of condensation of the water in the engine exhaust whether that engine is piston or jet.
In humid air the formation of vortices at the tips of the wings and/or flaps can produce a visible trail due to the the condensation of water at the tip of the cone of the vortex where both temperature and pressure are very low: but the intensity of the forces involved to do this exceed anything found in the natural atmospheric system by a magnitude or more.
Likewise the shock waves around any body, usually some kind of aircraft, moving close to transonic speeds can sometimes form a condensation cloud about itself which remains bound to it.
Whilst convenient for calculation and fairly precise for permanent gasses neither the Lagrangian nor the Euler flow fields can be used directly for gasses which contain a significant amount of condensible vapour such as humid air because they cannot handle the abrupt discontinuity in volume and temperature that result from sudden condensation. Nor in the case of humid air can they take into account the resultant precipitation of the condensate.
The only way to use them in such circumstances is compensating for this by making and applying approximations which may or may not be appropriate since they cannot be validated by direct observation.
So you see the article anna v linked to here:
http://noconsensus.wordpress.com/2010/10/21/456345/
may take an elementary approach but it is none the worse for that and far from being unsound is definitely not bogus as you so cavalierly suggest.
Kindest Regards
a jones, thanks for clearing up the contrails definition issue. I guess I was referring to what you see over the wings in near-saturated conditions which is decidedly due to pressure reduction, and probably is not often referred to as a contrail, though I am not sure of the proper name for it.
Condensation in convection occurs as air ascends and its pressure and temperature reduce eventually enough to reach saturation. In a reversible process, therefore, pressure reduction is necessary but not sufficient for condensation. More importantly you can’t get air to condense reversibly (adiabatically) unless you reduce the pressure first. It doesn’t happen spontaneously. So in this sense it is obvious that condensation is accompanied by a pressure reduction following the air parcel (lagrangian frame of reference). The paper therefore is not saying anything that is not trivially true when it says condensation goes with a pressure drop, since it is like saying it goes with rising air. The later argument about condensing out water in a moist saturated column seems disconnected with the first, because its pressure reduction is hydrostatic due to loss of condensate, another well known phenomenon. The idea of anything new here is not proven, making the claim of a new theory in the paper’s title bogus.
Stephen Wilde says:
October 23, 2010 at 3:08 am
__________Reply;
You are still leaving out the importance of the Lunar tides in the atmosphere, the declinational component moves the surges of tropical air masses off of the ITCZ with every equatorial crossing and brings them into the mid-latitudes to create the Rossby waves and the jet streams that form their boundaries.
Until you address the production of the multiple patterns of the ocean basin oscillations that are created by the lunar tides, and the interactions with the planetary heliocentric conjunctions, that send pulses of energy into the cyclonic patterns of global circulation, you will never be able to predict anything out farther than 5 to 7 days.
Thank you Richard but I don’t try to predict anything at this stage.
My purpose is to ascertain how the system works in practice so that we can discern the current long term direction of temperature trend in the troposphere and ascertain changes in the direction of such trends as soon as possible after they occur.
Once the direction of trend has been determined then that can assist in shorter term predictions or projections.
Those longer term trends seem to be much longer than any lunar induced trends in the atmosphere or oceans might be and I don’t need to identify those shorter term effects for my current purposes.
Once I have achieved general recognition of the model changes that are needed to identify the direction and scale of underlying trends then I might focus on shorter term aspects of the system but in the meantime people such as yourself are coming up with interesting ideas and if you can fit them into my over arching scenario then all well and good.
anna v says:
October 23, 2010 at 11:54 am
Jim D says:
October 23, 2010 at 8:15 am
“on the point about H2O and CO2, you don’t seem to realize GCM physics clearly can distinguish the absorption lines of H2O and CO2 and integrate this effect into their solutions.”
I realize very well that these people should go back and do a solid thermodynamics graduate course so they can realize that there is no “GCM physics”, just physics that must not be misused. Misuse of physics becomes evident when simple thermodynamic concepts are violated, as the fact that in thermodynamics there is no way to separate which radiation comes from what molecule.
It’s called spectroscopy, it’s used to determine how much CO2 there is in an automobile exhaust for example!
See here for an example of parts of the CO2 and H2O IR spectra:
http://i302.photobucket.com/albums/nn107/Sprintstar400/H2OCO2.gif
Phil. says:
October 24, 2010 at 8:02 am
It’s called spectroscopy, it’s used to determine how much CO2 there is in an automobile exhaust for example!
And in what chapter of thermodynamics does spectroscopy reside?
And thank you, I have already linked to the spectra of CO2 and H2O above.
From the beginning I have been saying that the confusion in climate science is in mixing up physics systems . Thermodynamics is one full self contained system and is the one appropriate to describe macroscopic behavior of bulk matter.
Quantum mechanics is usually the province of dimensions hbar . There are exceptions, lasers, superconductivity, superfluidity, semiconductors,.. where macroscopic effects, some bulk, are ruled by quantum mechanical rules. The underlying unifier is “coherence”. When macroscopic states retain coherence than macroscopic quantum effects can appear.
The atmosphere/land/oceans system is not a system where coherence can manifest, and thus it is ruled by ordinary thermodynamics. It makes no difference that individual molecules have a spectrum.
Once the photon leaves the molecule it falls in the province of radiation thermodynamics, it does not have the tag of its parent . CO2 and H2O radiations are interchangable thermodynamically.
Have “David Hoffer (10:43pm) and anna v. (12:00am) have adequately exposed the aphysical nonsense that Lacis et al. espouse as “known physics.”” ? No. Of course not.
But they have demonstrated that they do not understand the basic physics of radiative transfer. Most basic to doing accurate radiative transfer is spectroscopy. As noted by Phil (Oct 24 8:02 am) “it’s used to determine how much CO2 there is in an automobile exhaust for example!”
All absorbing gases in the atmosphere have a unique spectrum comprised of literally thousands of absorption lines (which serve as identifying fingerprints for each gas). We utilize what is called line-by-line calculations to insure that the radiative effects of each absorption line for each absorbing gas in the atmosphere are properly included and accounted for. Furthermore, radiative transfer deals only with whatever gases are in the atmosphere at the moment of the radiative transfer calculation, and not on how the gases got into the atmosphere, or whether they might condense and precipitate – that involves a different type of physics that is also handled by the GCM.
As the first step in radiative transfer modeling of the atmosphere, it is necessary to define the optical depth at each wavelength of the spectrum, going layer by layer throughout the atmosphere. (The optical depth is the product of the amount of the absorbing gas times the monochromatic absorption coefficient at the wavelength in question.) Monochromatic optical depths are linearly additive, say H2O plus CO2, plus anything else that may be absorbing at that wavelength. The corresponding transmission and absorption at that wavelength is given by the so-called Beer’s Law absorption (which is exponential extinction, or exp[- optical depth] on your hand calculator). Thermal emission involves a further step of making use of Kirchhofff’s Law which basically states that monochromatic thermal emission is equal to the Planck function evaluated at the layer temperature times the monochromatic absorptivity of that layer.
Doing the radiative transfer calculation for the current composition of the atmosphere tells us that the surface temperature of the Earth is about 60 F warmer than it would be if there were no absorbing gases in the atmosphere (the terrestrial greenhouse effect). We can perform the same (spectroscopic) radiative transfer calculations for different combinations of atmospheric greenhouse gases to establish that water vapor accounts for about 50% of the Earth’s greenhouse effect, with clouds contributing 25%, CO2 contributing 20%, and other minor GHGs the remaining 5%.
As we demonstrated in the Science paper, water vapor (about 90% of the current atmospheric amount) rapidly precipitated from the atmosphere when the non-condesing GHGs were zeroed out, because water vapor works like a feedback effect, showing clearly that it is the non-condensing GHGs that sustain the terrestrial greenhouse effect. Since CO2 accounts for 80% of the non-condensing GHG radiative forcing that sustains the terrestrial greenhouse effect, this makes atmospheric CO2 the principal control knob that governs the temperature of Earth.
Obviously, there is no obligation for you to take our word for accuracy of these conclusions. However, you are more than welcome to make full use of the basic facts and physics and perform your own verification of what is happening with global climate. If you go and do these calculations correctly, I feel more than confident that you will also reach the same basic conclusions.
“”””” David Socrates says:
October 23, 2010 at 11:57 am
George E. Smith (October 22, 2010 at 9:16 am ) referring to Michael Hammer (Oct 22, 2010 at 12.13 am) accuses him of being wrong about total solar irradiance because he used a value of 340W/ m^2 at the top of the atmosphere rather than George’s figure of 1366 W/ m^2. He says that there is no justification for dividing the higher number by 4 and cannot understand why people do it (“I don’t know why climatists insist on dividing the TSI by 4, as if the weather and climate responds to the average energy impinging on the surface. Try to get a desert surface temperature of +60 to + 90 degrees C, with 340 W/m^2 impinging on it continuously, 24/7”).
Oh really? “””””
Well yes Really.
Trenberth gives the thermal emission from the earth surface as 390 W/m^2 which is the calculated Black Body Radiation corresponding to a mean Temperature of 288K or +15 deg C
Soo clearly Michael’s 340 W/m^2 solar input is not enough to raise the surface Temperature even to +15 deg C and it certainly isn’tanywhere near enough to heat a tropical desert surface to +60 deg C or a hot pavement to + 90 deg C, even with total absorption. But something in the area of 1000 W/m^2 left over from the TSI value of 1366, after atmospheric losses to O2, O3, and H2O, and tiny bit to CO at 2.7 microns certainly is enough to reach those surface Temperatures.
I’ve only been doing Black Body Radiation Calculations as part of my job for about 50 years but I have already stumbled to that “trick” of deducing a Temperature from solar radii, and earth orbit radii; and I also do a lot of Optical Image and Illumination calculations on a regular basis, so I know how to get from a diffuse roughly Lambertian emitting surface to a n absorbing/scattering/ reflecting/emitting surface like a cloud, and how to apply the inverse 4th power with distance fall off (round trip) as wll as the cosin^8 (obliquity angle) to figure out how much returns to the starting point.
But when Mother Gaia starts adjusting earth’s weather and clmate according to statistical averages, instead of real time actual values; then we will have a planet devoid of any Temperature gradients, and energy/atmosphere/ocean currents so no weather or climate variations either.
Atmospheric water which is a permanent component in all three phases in the atmosphere (and the only one that is) ALWAYS reduces the amount of incoming solar spectrum energy that reaches the earth surface (land or ocean) no matter where and how that water is disperesed in the atmosphere. There are NO exceptions; more water vapor, or more clouds is ALWAYS less solar insolation at the surface; no matter what.
And if what Gavin et al say about CO2 and all other non condensing GHGs providing 25% of heating and H2O vapor and clouds providing 75% via feedback; then you have an oscillator, not a warming amplifier, since the loop gain is clearly greater than one; and in thermal systems you always have thermal time constant delays, that virtually always provide enough phase shift to guarantee oscillation; and with Gavin’s loop gain of four it is bound tbe a limit to limit oscillation; and so far that has never been observed; well in the last 600 million years.
Gavin compleltely misses the point that without H2O in the atmosphere there would be no cloud albedo effect or water vapor attenuation of incoming solar, and the ground level solar insolation would be much nearer to 1366 than to 1000, so you would have a massive additional heating of the oceans which woul soon put plenty of H2O in the atmosphere.
His experiment is a complete fiction; CO2 levels have never been lower that the present levels by much more than one doubling; so the temperature could never have been lower than about 12 deg C if the IPCCs 3 deg per doubling was correct; and in fact it hasn’t ever been lower than 12 deg C globally nor more than 22 deg C despite at least five doublings fromt he lowest CO2 levels. Without clouds, the earth albedo would be much lower and the equlibrium BB Temperature of earth would be much closer to 288 K than to 255 K; so their frozen iceball “experimental result” is a total myth.
anna v says: “Once the photon leaves the molecule it falls in the province of radiation thermodynamics, it does not have the tag of its parent . CO2 and H2O radiations are interchangable thermodynamically.”
In the radiation physics of models, they account for the fact the photons of different wavelength bands have different ranges in different absorbing gases. You are referring to broadband models that have not been used for a few decades now, but even those considered ‘overlap’ effects of CO2 and H2O by separating the calculations.
George E. Smith says:
October 24, 2010 at 2:04 pm
“And if what Gavin et al say about CO2 and all other non condensing GHGs providing 25% of heating and H2O vapor and clouds providing 75% via feedback; then you have an oscillator, not a warming amplifier, since the loop gain is clearly greater than one; and in thermal systems you always have thermal time constant delays, that virtually always provide enough phase shift to guarantee oscillation; and with Gavin’s loop gain of four it is bound tbe a limit to limit oscillation; and so far that has never been observed; well in the last 600 million years.”
Very good. I never took the “water vapor feedback” argument seriously enough to think it through to this consequence. But that really kills it for good.
Jim D says:
October 23, 2010 at 3:47 pm
Yes you can sometimes see the effect you describe in very humid air close to saturation. It is not due to the mean pressure reduction over the wing however. Much as we might be unhappy about it the streamline flow over the upper surface of a wing is far from perfect so small scale turbulence starts to enter it at some point behind the leading edge: which increases the drag. Again this micro-turbulence creates regions of extreme temperature and pressure drop causing air to condense: and the effect is amplified if the air contains tiny particulates of low mass and very small aerodynamic profile, classically smokes, which can become entrained in these miniscule vortices and serve to provide a centre for nucleation of the water vapour.
Now we may have been at cross purposes because I assumed you were referring to the article written by Jeff Id here: http://noconsensus.wordpress.com/2010/10/21/456345/ but now realise you may have meant the actual paper referred to in it here: http://www.atmos-chem-phys-discuss.net/10/24015/2010/acpd-10-24015-2010.pdf.
So although I almost never bother reading climate science papers, they generally regurgitate trivia, and let good scientists like Pielke senior direct me toward more interesting ones, but usually the abstract is all that is needed, I thought I had better read this one before commenting further, and did, and indeed looked up the previous papers as well.
Apparently this paper is causing some excitement in the climate world not least because it points out failings in the GCM models. I really cannot get excited about this, GCM models and their underlying assumptions are so full of flaws what does one more matter? However much money is spent on them they are neither use nor ornament.
Moreover almost any scientific paper is built upon previous knowledge and to call it bogus on the grounds that much of it is already known is strong stuff: by that standard 99% of papers would be such.
No the author’s claim of a new model is reasonable and they do acknowledge previous work and attempts to do this: of course at a time sixty years ago when nobody was very interested.
What in effect has become a world where numerical computation backed by enormous computing power is used to supposedly solve navier stokes equations they are trying to produce a solution using classical thermodynamics. It is very interesting that the lead author’s previous papers tried to consider these things in terms of the Carnot cycle. Well, on the right track I would say.
But they still have a long way to go: just as numerical models omit all but selected data as being too difficult to deal with they have not fully incorporated all of the necessary thermodynamics. I saw no dlelta G, the Gibbs free energy, in the papers. Perhaps they will get round to it.
So actually I think it is moderately original and interesting: but as aforesaid they have a long way to go yet.
Kindest Regards.
a jones, OK, I ended up putting a longer comment on that paper on Climate, Etc., but Air Vent had a good discussion too. Basically my view has not changed much, but the pressure-drop issue is interesting, though I think 3 different interpretations of that seem to be bandied about in the discussions. I mentioned 2 here, and a 3rd one in Climate, Etc., but I can’t claim to know which one the authors were talking about.
Jim D says:
October 24, 2010 at 2:17 pm
anna v says: “Once the photon leaves the molecule it falls in the province of radiation thermodynamics, it does not have the tag of its parent . CO2 and H2O radiations are interchangable thermodynamically.”
In the radiation physics of models, they account for the fact the photons of different wavelength bands have different ranges in different absorbing gases. You are referring to broadband models that have not been used for a few decades now, but even those considered ‘overlap’ effects of CO2 and H2O by separating the calculations.
I am not referring to any atmospheric radiation physics models.
I am referring to the basics of axiomatic theories to make the statement.
The assumption that because CO2 is stable while H2O has phase transitions CO2 radiation is more important than H2O radiation would only make sense if H2O could completely disappear from the atmosphere. As long as it remains there to the level of creating clouds, i.e. much larger quantities than the puny CO2 covers now, the model is basically violating thermodynamics.
Actually, in my opinion, they have shot themselves in the foot: they have proven their model is wrong and that in a peer reviewed publication !!!.
A Lacis says:
October 24, 2010 at 1:37 pm
But they have demonstrated that they do not understand the basic physics of radiative transfer. Most basic to doing accurate radiative transfer is spectroscopy. As noted by Phil (Oct 24 8:02 am) “it’s used to determine how much CO2 there is in an automobile exhaust for example!”
You mean a computer model of radiative transfer, no? No, I have not delved into them.
BUT in order to see if energy conservation is violated one does not have to enter every spectral line, because energy is defined in various systems. Spectroscopy and spectral lines belong to quantum mechanics and at a stretch quantum statistical mechanics. In each system there is energy conservation appearing in different forms. Thermodynamics, which is a meta-level over quantum statistical mechanics, has a different formulation of energy, still energy conservation laws are strictly defined.
If you want to use spectroscopy for the atmosphere you should do it with the formulation of quantum statistical mechanics, ensembles and all. From what I know all calculations are done with classical thermodynamic equations. In classical thermodynamics the molecular parent of radiation is irrelevant, the energy spectrum is. By introducing a non thermodynamic gauge/logic you are violating the basic assumptions on which rest the solutions of the equations that give this bizzare result.
The presence or absence of a molecule could make a difference in the spectrum, if only CO2 were left most of the atmosphere would be transparent. BUT you still have water vapor when you remove the rest, if you have clouds, and water vapor covers the hole of CO2 and your assumptions fall on their face. The rational result if your model were correct would be to show that the temperatures with CO2 are higher than without CO2.
Actually, that would be the first test I would be making if I were building a model. And btw I have been working with computer model simulations for over forty years, from when the models were primitive, in particle physics.
As I said above, you have proven your model is wrong.
I note that the concentration of H2O in the atmosphere may be over 4,000 ppm near the surface and is less than 10 ppm at the base of the stratosphere. This allows H2O to have the lowest IR radiation escape altitude of any major greenhouse gas. I suspect the authors of this article, by concentrating on CO2 may have been too quick to dismiss the role H2O has on warming and cooling the lower atmosphere. I think we need to know if the -60 degree tropopause temperature level is free to respond to surface temperature changes like a leaf in the wind or if it is more or less anchored to its position in the atmosphere.
I note that most H2O IR emission lines do not appear to coincide with CO2 absorption spectra. At the top of the troposphere, these are the emissions that must finally export convected thermal energy to outer space.
“”””” A Lacis says:
October 24, 2010 at 1:37 pm
Have “David Hoffer (10:43pm) and anna v. (12:00am) have adequately exposed the aphysical nonsense that Lacis et al. espouse as “known physics.”” ? No. Of course not.
But they have demonstrated that they do not understand the basic physics of radiative transfer. Most basic to doing accurate radiative transfer is spectroscopy. As noted by Phil (Oct 24 8:02 am) “it’s used to determine how much CO2 there is in an automobile exhaust for example!” “””””
I didn’t bother to cut and paste your entire post; just enough to identify the post. People can go and read the original.
I didn’t see anything in your post; or for that matter in your SCIENCE paper; where you elaborated on the fact that H2O in any and ALL of its three phases as a permanent component of the atmospehre, in ALL of those three phases; ALWAYS reduces the amount of incoming solar spectrum ground level insolation.
Since it is primarily solar spectrum energy directly from the sun; that proceeds deeply into the ocean where it stores for a considerable time; whereas; as is well known, downwelling LWIR thermal radiation from the (GHH and solar )warmed atmospehre is all absorbed in about the top 50 microns (five times the 1/e absorption depth) of the ocean (mostly) surface; where it is most likely to cause prompt evaporation of more H2O, than it is to proceed by conduction into the ocean depths; then one would conclude that anthing that ALWAYS reduces the ground level solar insolation must result in overall cooling; since it is THAT solar radiation; that is just about the ONLY significant external energy input to this planet.
And more clouds and water vapor of any kind; anywhere in the atmosphere always (no exceptions) reduces ground level solar energy.
Also I didn’t notice in your SCIENCE paper; that a massive reduction of H2O in the atmosphere would eventually lead to a reduction of cloud cover; and the earth albedo would collapse; so the equilibrium black body temperature of the earth would increase above the usual 255 K given for the present assumed value of albedo; most of which results from cloud cover; not from snow or ice cover. The reduction from a TSI of 1366 W/m^2 to about 1000 W/m^2 ( at the surface) by the atmosphere (clear sky) is largely due to H2O and of course O2, O3, and to a minor extent CO2 in the 2.7 micron band. Absent that loss, and the earth equilibrium Temperature is not far different from 288 K, which is what it is claimed to be at present.
There’s a reason for snow and ice in the polar regions; there’s not much ground level solar irradiation of those surfaces so even if they have high reflectance; and the open water would because of the increase in Fresnel reflectance beyond the Brewster angle; there’s not much energy to reflect.
Your SCIENCE paper completley ignores the atmospehric effcts on the direct energy input fromt he sun; and you would have the mother of all warming “forcings”; if atmospheric water plummeted; and let more sunlight in.
I should add to the above that Frank Wentz (RSS) et al in SCIENCE for July-7 2007; “How Much More Rain will Global Warming Bring?” cite satellite observations to show that a one deg C rise in mean global surface temeprature results in a 7% increase in each of; Total global water evaporation, total Atmospheric water content; and total global precipitation; which must balance evaporation.
This was in sharp conflict with the GCMs which they assert that while agreeing on the atmospheric water content increase, only predicted a 1% to 3% increase in evap/precip. That’s as much as a factor of 7 discrepancy between actual observations (reality) and computer model predictions.
They did not state; but I have conjectured that a 7% increase in total global precipitation would likely be accompanied by about a 7% increase in total precipitable cloud; since it is fashionable to have clouds with your precipitation. That increase could be in the form of increased cloud area, increased cloud optical density, or increased cloud persistence time; or some combination of those.
In which case one would expect that a one degree C increase in mean global Temperature would result in a sizeable reduction in ground level solar spectrum insolation; both from the 7% increase in H2O vapor with its significant solar spectrum absorption; and the decrease in ground sunlight due toe increased cloud top reflection, and increased cloud absorption of incoming solar energy.
That to me is a simply huge negative feedback cooling effect; regardless of what the water does with the secondary issue of surface or atmospheric LWIR thermal radiation.
So how come you continue to run your models with the assumption that H2O vapor and clouds area positive feedback warming effect.
Wentz et al’s data also supports my contention that a cooling results in significant cloud reduction (I conjecture of the order of 7% per deg C of cooling); whcih of course then allows an increased ground level solar insolation which would stop the cooling in its tracks.
I suggest that it is the water in all its three phases that controls earth’s Temperature and not CO2; which can’t even hold up the temperature at night in a high altitude arid desert (sans H2O).
As a concluding comment on this topic, it appears to me that perhaps the greatest obstacle in conducting a meaningful discussion on the role of atmospheric CO2 as the principal cause of the ongoing global warming, is the apparent lack the lack of basic understanding of radiative transfer, and of the operating mechanics of the terrestrial greenhouse effect.
Unfortunately, there is no “Radiative Transfer for Dummies” book on the market that would provide a quick study of the essential principles. There are a number of technical books that are available by Goody, Mishchenko, Liou, Stephens, among others. There is also a fairly readable “A First Course in Atmospheric Radiation” by Grant Petty. But all of these books require a significant investment of time and effort to achieve some degree of fluency in radiative transfer aspects, particularly those with application to solar and thermal radiative transfer in climate modeling applications.
It may be a coincidence, but I know of no one who has a good understanding of atmospheric radiative transfer who is also a skeptic about global warming.
“It may be a coincidence, but I know of no one who has a good understanding of atmospheric radiative transfer who is also a skeptic about global warming.”
It may be a coincidence but I know of no one who has a good understanding of atmospheric non radiative transfer (of energy) who is also a believer about (anthropogenic) global warming.
How about those believers getting a grip on the true scale and speed of variability of non radiative transfers before they start pretending that they know what they are talking about ?
This appears to me to be what is really going on:
“Why Have The Jet Streams Moved Back Toward The Equator ?
When global warming alarmism was largely unopposed the observed poleward
shift of the jet streams until around 2000 was described as a permanent
consequence of our CO2 emissions.
Although I spotted the reversal of that trend as long ago as 2000 it is only
now that those more recent changes have started to be acknowledged by the
mainstream. Meanwhile the global warming proponents have been silent on the
issue.
There is new data from solar expert Joanna Haigh which confirms my suspicion
that the temperature of the stratosphere (which then controls the air
pressure distribution patterns in the troposphere below) is in reality
controlled by the temperature of the mesosphere above it rather than by the
level of incoming UV acting on stratospheric ozone.
In turn the temperature of the mesosphere is controlled by the number of
incoming solar protons which variably deplete ozone in the mesosphere to
reverse the temperature trend of the mesosphere (and the stratosphere below)
as against that of the thermosphere and the troposphere.
So an active sun with a stronger solar wind destroys more ozone in the
mesosphere which then cools. The temperature of the stratosphere then
declines with the tropopause rising and the air circulation systems being
drawn poleward. The opposite process occurs when the sun is quiet.
It is only possible to see a poleward shift in the jets if the stratosphere
cools and the tropopause rises and for an equatorward drift the stratosphere
must warm and the tropopause fall. Observations therefore require that the
sign of the solar effect on the stratosphere must be reversed as per Haigh’s
data. When the sun was more active the stratosphere cooled and the jets
moved poleward but that cannot happen if the correct sign for the
stratospheric response is warming because that would drive the jets back
equatorward instead.
Furthermore human CO2 cannot be the cause because during the Mediaeval Warm
Period the jets were more poleward when the sun was more active. It has to
be the natural order of things.
Ozone holes then develop at the poles because the solar protons being
charged particles are pulled in at the poles where maximum destruction of
mesospheric ozone then occurs and the size of the holes varies closely with
the strength of the solar wind.
Climate change is therefore also linked link with both the solar wind and
the interaction between the magnetic fields of sun and Earth as many have
previously suggested.
The poleward movement of the global cloud bands decreases albedo by reducing
total cloud quantities and reducing cloud reflectance as the clouds move to
regions of less powerful sunlight.
More energy then enters the system from more solar shortwave entering the
oceans. The oceans then ration and regulate the rate of release of that
energy back to the air.
So an active sun still gives a warming Earth system and a quiet sun gives a
cooling Earth system but not in the way usually proposed. It is an indirect
process greatly amplified by the albedo changes.
This is a matter that still needs to be understood and applied correctly by
both sceptics and warming proponents alike.”
I know of no model that gives due weight to the effect of solar proton variability on the ozone content of the mesosphere and so the temperature consequences in both mesosphere and stratosphere.
So far, I have not been able to find a single chart that shows the spectrum of infra-red energy radiated from the atmosphere at the tropopause and escapes to outer space. All the charts that I have found seem to show radiation from the surface that has been attenuated by the various greenhouse-gas absorption-bands and they usually stop at wavelengths shorter than 6 microns. All the heat that is being convected upward must escape to outer space or else we have a situation like a blocked chimney.
When I do not see standard and openly available measurements of the thermal spectrum of convection-column radiation escaping the Earth’s atmosphere, I am not confident that the state of knowledge on this subject is sufficiently mature to make valid assessments of the role of CO2. There must be some reason other than the convection-driven adiabatic lapse rate for tropopause temperatures being as cold as minus sixty degrees C.
I don’t know why my modest contribution of October 23, 2010 at 11:57 am should have brought forth such an onslaught from George Smith (October 24, 2010 at 2:04 pm) .
All I was doing was explaining why when talking about global averages one has to divide the incoming solar flux by 4. I also though I had dealt with his (valid) point that the average value so determined wouldn’t be enough to heat up a desert floor (he says “Try to get a desert surface temperature of +60 to + 90 degrees C, with 340 W/m^2 impinging on it continuously, 24/7”). Yes, as I said before, of course 340W/m^2, even shining continuously for 24 hours, wouldn’t do it because that’s not high enough– duh! But near the equator at midday for a few hours the flux would be more like the incoming solar flux of 1366 W/m^2, multiplied by 0.7 to take into account the Earth’s reflectivity (albedo), i.e. 956 W/m^2. Using Stefan’s Law, F = σT4, where F is the radiative flux in W/m^2, σ is the Stafan-Boltzmann constant, and T is the absolute temperature in degrees Kelvin, and substituting F = 956 W/ m^2 and σ = 5.670400 x 10-8 W m^-2 K^-4 gives a surface temperature of 360K or 87degC. Hot enough for you, George?
The rest of his rant was just showing off. If he knows so much more than the rest of us, what a pity he doesn’t take a more positive approach and help us to advance our puny knowledge. Otherwise we will collectively fall into the warmist trap of writing self-congratulatory stuff that does not move the argument along in any useful direction. Since we are all on the same side, that would be madness.
A Lacis says:
October 24, 2010 at 1:37 pm
A Lacis says:
October 25, 2010 at 9:57 pm
Predictably, your reasoning in above-cited posts ignores the fundamental principle of causal system phase relationship that I raised in my 12:54pm post on 10/23 and diverts attention to the radiative transfer calculations done by computer models, as if that was all that mattered in determining the thermodynamics of the climate system.
Laboratory spectroscopy of various gases (which can produce appreciably
different absorption/transmission spectra, depending on whether cylinders
or slabs are subjected to radiation) is far from definitive of the
atmospheric heat transfer, where H20 vapor bands overlap that of the trace
GHGs. Beer’s law of additive optical depths does not apply intact in such
cases. And when convection and phase changes take place, radiative
transfer alone becomes wholly inadequate in characterizing the total flux
of thermal energy through the system. It is that flux, rather than the
radiative spectral distribution that (along with the specific heat of the
substance and its in situ density) determines the temperatures obtained.
What is physically nonsensical is the premise that, absent any CO2, H20
would completely precipitate out of the atmosphere and the “greenhouse
effect” would collapse. Forced convection due to differential heating of
the surface is not at all dependent on an absorbent atmosphere creating a superadiabatic lapse rate and inducing overturning convection. And we know
that, even at ice-age terrestrial temperatures, moist convection still
takes place, most certainly in the tropics, where all plant species would
become extinct very quickly without precipitation. As careful energy
transfer experiments from different climate zones around the globe have
shown consistently, it is that chaotic transfer of sensible and latent heat
to the bulk constituents, rather than absorption by trace GHGs, that
dominates in warming the base of the troposphere. And that is precisely
where backradiation–the essence of the capacitive “greenhouse
effect”–is discharged.
It seems that you and your colleagues are unacqainted with the workings of thermodynamic systems in the geophysical setting and show no interest in abundant
experimental measurements that conflict with your modeling premises. I’m
sure that once you expand your comprehension, you’ll come to the conclusion
that the trace GHGs control nothing. They make only a minor contribution to
the dispersal of thermal energy to the bulk constituents of the atmosphere
and back to the surface–in ever-decreasing quasi-logarithmic proportion to their
concentrations. The handwaving idea of an amplifying “feedback” is merely a modeling
fiat–an aphysical phantom.
Any further discussion of an essentially thermodynamic problem that fails to acknowledge all the basic components of enthalpy is pointless.
“”””” David Socrates says:
October 26, 2010 at 3:41 pm
I don’t know why my modest contribution of October 23, 2010 at 11:57 am should have brought forth such an onslaught from George Smith (October 24, 2010 at 2:04 pm) .
All I was doing was explaining why when talking about global averages one has to divide the incoming solar flux by 4. I also though I had dealt with his (valid) point that the average value so determined wouldn’t be enough to heat up a desert floor (he says “Try to get a desert surface temperature of +60 to + 90 degrees C, with 340 W/m^2 impinging on it continuously, 24/7”). Yes, as I said before, of course 340W/m^2, even shining continuously for 24 hours, wouldn’t do it because that’s not high enough– duh! But near the equator at midday for a few hours the flux would be more like the incoming solar flux of 1366 W/m^2, multiplied by 0.7 to take into account the Earth’s reflectivity (albedo), i.e. 956 W/m^2. Using Stefan’s Law, F = σT4, where F is the radiative flux in W/m^2, σ is the Stafan-Boltzmann constant, and T is the absolute temperature in degrees Kelvin, and substituting F = 956 W/ m^2 and σ = 5.670400 x 10-8 W m^-2 K^-4 gives a surface temperature of 360K or 87degC. Hot enough for you, George?
The rest of his rant was just showing off. If he knows so much more than the rest of us, what a pity he doesn’t take a more positive approach and help us to advance our puny knowledge. Otherwise we will collectively fall into the warmist trap of writing self-congratulatory stuff that does not move the argument along in any useful direction. Since we are all on the same side, that would be madness. “””””
Well David you are free to take it or leave it any way you want. I’m sorry that I missed your earlier post:-
“”Yes, as I said before, of course 340W/m^2, even shining continuously for 24 hours, wouldn’t do it because that’s not high enough– duh! “”
Perhaps you can say where that was so, I could go and read your entire post so that I don’t miss anything .
Apparently you don’t find any problem with a model that clearly cannot replicate known conditions on earth. Since Black Body Radiation is so highly non-linear (T^4 for Total Radiant Emittance; or even T^5 for Peak Spectral Emittance); ANY model based on static averaged global spatial and time varying data, is bound to lead to incorrect conclusions; and in this case to give a completely wrong value for earth’s energy balanced “equilibrium” Temperature; where the “” “” simply indicates that the earth is never in equilibrium; if for no other reason than it rotates under the sun’s energy beam.
Because of that high non-linearity; the hot arid desert regions of the earth at the peak of their daytime high Temperatures; are the main cooling spots for the planet; since that is the conditions under which the earth is radiating energy to space at its highest rates; and because of the Wien Displacement law; is also radiating at a wavelength range that is less affected by CO2 than is the case for average global conditions; making the cooling effect even more efficient.
In contrast the Earth’s polar regions; and particularly the central Antarctic highlands are so cold, that sometimes they are only radiating at 1/6th of the global average rate; and moreover are doing so with a spectrum that peaks right on the CO2 15 micron absorption band; which enhances the CO2GHG effect for those regions. Maybe that is part of the reason why they say the earth is warming more in the polar regions; the cooling efficiency there is so much worse than in the tropicl deserts; that the poles can’t lose heat fast enough.
And of course you already know all that; but then; the reason I post such stuff; is not for people who already know it; but for perhaps even one person out there who may not. I’m sorry I can’t take a more positive approach ; and as it turns out, I have no information; one way or another, about the level of knowledge of anybody; either reading here or posting here; and I come here to learn what I can myself.
Unfortunately I don’t seem to find much being offered by those who come here; who clearly have better knowledge and credentials than I have. The AGW proponents seem to offer little but ad hominem dismissal of anyone who isn’t locked arm in arm with their view.
I don’t have any skin in this game; I care not a whit about whatever political angles some want to put on this subject (although I do have opinions on that). I’m only interested in one thing; and that is that the science get’s corrected. Author Lacis dismisses the “skeptics” as simply incompetent to understand his writings and explanations. I don’t understand them either; they simply don’t make any sense to me; but I’m not a skeptic; I’m quite convinced that the concensus science is quite wrong.
No; I don’t deny there has been recent warming (at least up to 15 years ago); No I don’t deny that muman activities are altering the environment; no I don’t deny that CO2 is a “greenhouse gas” as that term is understood in climatism; and no I don’t deny that the so-called greenhouse effect as it applies to the atmosphere is real; and does result in warming of the atmosphere. I don’t deny any of that. I don’t deny that the Arctic ice has been lessening; at least in recent years; or that it has had some history of waxing and waning. I don’t deny any of that.
But I also believe that it isn’t a problem we should worry about; and it certainly isn’t anything we can do anything about (has nothing whatsoever to do with environmental pollution; which we can do something about).
But as to the so-called “climate science”; I have no confidence in either the purported global observations of Temperature data; and would cite a John Christy et al paper from Jan 2001 to justify that; and I have no confidence in the computer modelling; as to its treatment of H2O including clouds; and would cite a SCIENCE paper by Wentz et al for July-7-2007 to justify that.
Also, I have a full time paying job with a private enterprise profitable business; so I don’t have time to do independent research in this or any other field; and it is only that my computer chatters away doing simulations and optimisations for me; that even allows me to visit here from time to time ;while it is thinking.
But my suggestion David, is to just bypass my posts, and go on to those more in tune with your interests; I know I can’t possibly read all the traffic here; so whole threads can go by without a glance from me; I only read those I think I can learn from or contribute to. If that helps even one person to some understanding; then it is worth it; but I’m not here to argue with those who know much more about it than I ever can.
As an aside; Kelvins are not degrees; those apply to Celsius or Fahrenheit scales of temperature.