by Judith Curry
Martin Hertzberg, one of the authors of Slaying the Sky Dragon, has requested that we assess his paper (published in E&E). Since we had so much “fun” with Part I, I said sure.
EARTH’S RADIATIVE EQUILIBRIUM IN SOLAR IRRADIANCE
Martin Hertzberg
The average equilibrium temperature for all the Earth’s entities involved in its radiative balance with the Sun and Space, is given by:
T (e) [K] = 278.9 [ ( 1 – α ) / ε ] 1/4
The controlling factor is the ratio of the absorptivity, a = ( 1 – α ), to the emissivity, ε . The quantity α is the Earth’s albedo. It is shown that relatively modest changes of only a few percent in α, brought about by variations in cloudiness, are sufficient to account for the observed 20th Century variations in Earth’s measured temperature, provided that such variations in cloudiness can cause an imbalance in the ratio ( 1 – α ) / ε . The analysis suggests that in the long run, the absorptivity to emissivity ratio is near unity, as required by Kirchhoff’s radiation law, which ensures a moderate average temperature of about 5.7 C for the Earth’s surface entities. That calculated temperature is in fair agreement with the observed average temperature of those entities, whose mass average is dominated by the mass of the oceans. Except for the influence of clouds on the albedo, no assumptions are needed regarding the detailed composition of the atmosphere in order to explain the observed small fluctuations in the 20th Century temperatures or the larger, longer-term variations of Glacial Coolings and Interglacial Warmings.
As with Part I, I am not going to write a review here. But this one is much simpler than Claes Johnson’s chapter, the only equations are algebraic. And it has a painful misunderstanding of Kirchoff’s Law. But it was published, albeit in Energy & Environment, a journal that is quite erratic editorially (this isn’t to say that the don’t sometimes publish worthwhile papers). So lets give it some attention.
I dismissed reviewing Hertzberg’s chapter in the Dragon book, entitled “History of Encounters with the Sky Dragon.” The chapter stars with a rambling personal history of his encounters, with ample “fear mongering hysteria” etc. It goes on for 30 pages or so, no science.
Moderation note: this is a technical thread, moderated for relevance. Make your general comments on the Part III thread.
Amazing that someone would so confidently publish a paper that relies on understanding of Kirchhoff’s law when they don’t know what Kirchhoff’s law is.
From .p7:
“As can be seen from the graph, for an average albedo of 0.367 (which
equates with an absorptivity of 0.633) the only way one can obtain sub-zero
temperatures as low as -20 to -25oC, is to have an almost perfectly emissive Earth (emissivity near unity). Such a unit emissivity assumption, however, directly contradicts the use of an albedo of 0.367. Since most of the albedo is caused by cloud cover, it is impossible for Earth to radiate out into Space with unit emissivity if 37% of that radiation is reflected back to Earth, or absorbed by the bottom of those same clouds. Even for those portions of Earth that are not covered with clouds, the assumption that the ocean surface, land surfaces, or ice and snow cover would all have blackbody emissivities of unity, is unreasonable. ”
Kirchhoff’s law is that emissivity as a function of wavelength and direction is equal to absorptivity at the same wavelength and direction.
As explained for beginners in Planck, Stefan-Boltzmann, Kirchhoff and LTE.
Perhaps E&E needs an editor who has read a few introductory textbooks on heat transfer..
science of doom, thanks for stopping by
“Kirchhoff’s law is that emissivity as a function of wavelength and direction is equal to absorptivity at the same wavelength and direction.”
?? Is this not true only for bodies that are at a uniform temperature and are under a constant amount of radiation? I don’t think it holds for a cold rock in the early morning sun. But I may be wrong, and if so, I await correction.
It is for a body in thermal equilibrium – in accordance with the law of thermal radiation – so yes you are right
At normal temperatures, emissivity and absorptivity only apply to IR radiation, so solar radiation has nothing to do with this law, here on Earth at least, though it may have a bearing on what goes on inside the Sun. The big mistake was to even mention solar radiation in this law, as Earth objects are not emitting light, being generally not hot enough.
Pedant (smile). I did say ‘thermal equilibrium’. But the planet is in some sort of dynamic energy disequilibrium of course and it was this that I had in mind. Energy in less energy out (at TOA) = delta change in global energy storage (oceans, atmosphere and some internal energy)
This can be expressed as:
Ein/s – Eout/s = d(GES)/dt
By the law of conservation of energy – the average unit energy in (Ein/s) at the top of atmosphere (TOA) in a period less the average unit energy out (Eout/s) is equal to the rate of change (d(GES)/dt) in global energy storage (GES). The formula is an adaptation of the hydrological equation of storage.
This is a fun little equation to use to play around with the trends of solar irradiance and upward radiative flux. For instance, there is a suggestion that the planet cooled a little last decade – but that happened as solar irradiance fell to a minimum in 2008 in solar cycle 23. The net trend in CERES outward fluxes seems not very convincing either way.
If there is any planetary warming or cooling – then an energy imbalance exists. The point of the Hertzberg manuscript seems to be that an energy equilibrium exists unless it doesn’t as a result of cloud changes.
My point is that a dynamic energy imbalance exists as a result of a whole heap of factors – primarily cloud. There is both surface observational evidence for low level stratiform multi-decadal cloud change in the Pacific and satellite evidence for big multi-decadal cloud change especially in the tropics. Nothing to do with global warming – but with SST which is mostly to do with the patterns of Pacific variability.
afaik, Kirchoff law is valid in two cases: line by line in general, and as a whole (like used in the paper) in the case of perfect grey bodies. Grey body can be seen as a black body combined with a semi transparent mirror whose reflexivity is independent on wavelength.
The first error of the article is that it does not say explicitely that it expect (at least on average, like K. law was expected to be respected on average) the earth to act as a grey body.
The second point is that temperature that will be derived is a global average T. This seems to be difficult to be defined properly, like for any system out of equilibrium, but an attempts may be the average microscopic kinetic energy (linked to local temp, defined more easily because we can have local thermo equilibrium) over the whole part of earth suceptible to radiate or absorb. i.e the whole atmosphere, groung surface and ocean surface, maybe both up to a depth which can participate to heat exchanges on the time scale considered. Well, this is really not easy to define and I think it is the weakest part, if some arbitrary choice in the depth of water to consider can change the conclusion then we are in trouble. And anyway, this is not necessarily related to the experienced ground Temp, which is what is more interesting for policies (well, even that is not clear, what is more interesting are local indicators linked to food productivity, destructive extreme weather events and forcing on ecosystems (sometimes linked to min winter temp for example).
With those 2 difficulties in mind, I find the paper interesting, even if I agree it is much closer to a quasi-philosophical prospective paper than anything allowing to build prediction. Note that the current “state of the art GCM” have not shown to be so good at prediction, in particular for the policy-relevant indicators mentioned above, while have been built precisely for that. So I think it is not fair to dismiss prospective weak equilibrium approach like this, just because they are at this stage more hints than proper theory and not ideal for policy anyway, when reductionist approach are so far from validated.
What I’d like to see is if the earth system as a whole and on average (the longer the better) can be considered as a grey body, ie is the global spectrum reflected/emitted from earth can be reasonably approximated by a grey body, something like alpha*spectrum_sun+beta*black_body(T_earth), with T_earth close to an “earth average temperature”. If it is, maybe the global approach explained by the author can be developped….
Yeah, too bad he forgot about the integral. It’s readable though, and that’s a big improvement.
He is suggesting that, if it weren’t for cloud changes in the 20th century, the planet would be in energy equilibrium? You would probably have to add a few other factors to cloud – such that a better assumption must be that of a dynamic energy imbalance rather than Kirschoff equilibrium.
Not that cloud doesn’t change – http://www.earthandocean.robertellison.com.au/
Judith: before this gets going, I would ask that you remind all the commenters to be civil. The emotional terms “crank,” “crackpot,” etc. do not foster good discussion and should be discouraged. The last thread on the “dragon” was not a good example in this regard, and I think that, by your silence, you were implicitly supporting some very hurtful, meaningless, and nonsensical comments. My $.02.
Good suggestion. So far you are the only person on this thread that has had a comment deleted for lack of civility and relevance.
This is just another example of why E&E is not regarded as a legitimate scientific source among people in the field. This article is written as though it were done by a first year undergraduate who just got out of a class learning about Kirchoff’s law, and it was either not explained to them properly or they were busy texting on their phone while the instructor was talking. Perhaps the instructor said “we’ll cover the rest next week.” What I find most bizarre, is that people would entertain the possibility that the whole climate science community would miss something so simple. Usually if you think you discovered a completely new and revolutionary idea based on a couple of algebra maneuvers on a napkin, you might want to re-check your assumptions and physical understanding. Naturally, such curiosity was outside the scope of what the ‘Slaying the Dragon’ authors were willing to do.
Some other comments have already pointed this out. In general, the emissivity will not be 1-albedo. Absorptivity and emissivity must only be the same when averaged over identical frequency weighting functions, and so the only thing required by Kirchoff is that the Earth’s “visible” emissivity is 0.7, but the emission in this frequency range is negligible for Earth-like temperatures.
Seeing as the only point of the paper rests on this fallacy, it’s probably not worth discussing further. The other thing though is that just because a drop in albedo *can* cause temperatures to rise doesn’t mean it is. You actually need to go through attribution efforts, examine spatio-temporal signatures of albedo changes, explain how GHG’s aren’t warming as well, etc. This is just intellectual laziness if it’s not an attempt to confuse people.
Absorptivity is 1 – alpha. Neglecting for a moment that the law relates to thermal equilibrium – reflection of SW from cloud is the relevant emission. Yes the planet reflects visible light as a function of albedo.
Less rant and more thought about basic principles please.
More attention to English before worrying about the science. Reflection is not the same as emission. Reflection is light being scattered and this has nothing to do with thermal emission.
Oh please – read the manuscript before offering ill informed comment – it’s in English. EARTH’S RADIATIVE EQUILIBRIUM IN THE SOLAR IRRADIANCE
Chris was saying that there were no emissions from the planet in the visible band – well yes but there is reflectance which the paper explicitly includes as albedo.
We have a law that can be expressed as: α = ε – where α is absorptance and ε is emittance. (http://web.mit.edu/16.unified/www/FALL/thermodynamics/notes/node135.html)
Hertzberg expresses it as: ( 1 – α ) /ε = 1 – where α is in this case albedo.
In implies that all energy in is in the visible band – which is far from the case. This just can’t be a valid expression of Kirschoff. Having done some quick internet research – visible energy does not seem out of the question entirely but to then ignore solar infrared seems to be going too far.
Of course a global energy equation at TOA using the 1st law of thermodynamics is fairly simple – Ein/s – Eout/s = d(GES)/dt – see above.
Nope you are missing the point, the argument neglects the frequency dependence of the absorptivity/emissivity. The albedo is the albedo in the VISIBLE. This has nothing to do with emission and absorption in the IR and the flim-flam about the radiative balance (section 2) is just that because the author does not recognize this either.
JAE, Kirchoff’s law is simple textbook stuff you learn in undergrad courses on atmospheric radiation or physics. It’s not something people publish peer-reviewed articles about. If someone said gravity isn’t real because birds fly, you probably wouldn’t take it too seriously. And if a journal allowed that to be published, you’d probably put much less stock in their ability to filter quality work through. I don’t see how a peer-reviewed reference is required to understand this basic logic, regardless of whether you like my style of “ranting.”
JAE,
The real formulation of Kirchhoff’s law is in every basic textbook on heat transfer.
The writer of the paper didn’t know it.
The editor didn’t spot it.
What’s in doubt for you here? The textbooks?
Or you think basic textbooks actually back up Hertzberg?
p553 of an online textbook A Heat Transfer textbook by Profs Lienhard:
“Kirchhoff’s law is a relationship between monochromatic, directional emittance and the monochromatic directional absorptance for a surface that is in thermodynamics equilibrium with its surroundings.”
It is worth having a read of the few pages following.
By the way many people might appreciate the link above. It is a high quality heat transfer textbook and available free.
I also can scan the relevant page of Fundamentals of Heat and Mass Transfer by Incropera and DeWitt (2007). Would you like me to post a link to a page image?
Many of these people do actually believe the textbooks are false. Thus Steven Goddard’s insistence that physical chemistry textbooks about partial pressure and freezing temps are wrong, and that Antarctica actually does suffer from dry ice snow.
Or some of Curry’s doubts regarding climate science, to be blunt.
Post links and text snippets all you want, it won’t change a thing.
On my statement:
“Kirchhoff’s law is that emissivity as a function of wavelength and direction is equal to absorptivity at the same wavelength and direction.”
JAE asked February 4, 2011 at 10:14 pm:
“?? Is this not true only for bodies that are at a uniform temperature and are under a constant amount of radiation? I don’t think it holds for a cold rock in the early morning sun. But I may be wrong, and if so, I await correction.”
Kirchhoff’s law was established under conditions of thermal equilibrium, as you can see in my later extract from a textbook (February 5, 2011 at 12:48 am.
The formulation of the law already invalidates the central assumption of the “paper” by Hertzberg.
That is, spelling it out in detail: there isn’t a formulation of Kirchhoff’s law which says that absorptivity = emissivity no matter if we are considering different wavelengths.
If you read the article I linked – Planck, Stefan-Boltzmann, Kirchhoff and LTE, you will see the explanation of why emissivity as a function of wavelength and direction = absorptivity at the same wavelength and direction EVEN in the condition of no thermal equilibrium (TE).
This is also explained in textbooks, although more advanced ones, e.g., see the quote from Siegel & Howell in my article. In the basic textbooks the detailed explanation (of why emissivity=absorptivity is still valid outside of TE) is usually skated over.
In any case, there is no formulation of Kirchhoff’s law, in or out of TE, that says that absorptivity = emissivity no matter what the wavelength.
Therefore, the writer of the paper doesn’t understand the very basics of the subject.
In any case, there is no formulation of Kirchhoff’s law, in or out of TE, that says that absorptivity = emissivity no matter what the wavelength.
http://en.wikipedia.org/wiki/Kirchhoff's_law_of_thermal_radiation
says
At thermal equilibrium, the emissivity of a body (or surface) equals its absorptivity.
randomengineer :
I assume you are having a laugh. You could also point to many blogs or “papers” that also write an incorrect formulation.
Find 10 textbooks that explain radiant heat transfer and you will find 10 correct explanations of Kirchhoff’s law.
If you check enough textbooks that are off-topic I’m sure there are some with sloppy definitions.
But I would be amazed if you found a textbook that said “this identity is wavelength independent”.
You aren’t getting it. The WIKI article goes on to talk about wavelengths:
In the most general form of the theorem, this power must be integrated over all wavelengths and angles.
I’m pretty sure that Hertzberg, who wrote the paper, is probably well aware of wavelengths, referring specifcally to “ensemble of entities” (p. 90) thus corresponding to the general integrated form.
I don’t understand the nitpick. Not talking about wavelengths indicates that he has K Law wrong? Please. Seems to me he’s using the “general form” (integration) so as to argue something else entirely.
Well crud. I did a poorly formed a close bold tag after the word ANGLES which was supposed to indicate the end of the quote.
Maybe some nice moderator can close the tag that I didn’t close properly in my previous comment.
The earlier discussions led me to check, how Kirchoff’s law was originally formulated and how it appears presently in literature. It turns out that there are very many formulations, whose equivalence is not at all obvious without rather deep understanding of the issues involved.
The most powerful and therefore most useful formulation states that the emissivity is equal to absorptivity at each wavelength (or frequency) separately. This formulation does not usually require any additional statements about thermal equilibrium although there are situations, where one must assume something of that nature.
If the emissivity is equal to absorptivity at each wavelength separately then it is also equal for a wider spectrum if the wavelengths are weighted equally in absorption and emission. This is a very strong requirement and limits severely the straightforward use of the Kirchoff’s law. In practice this is used as the requirement that the source of incoming radiation must be a black body at the same temperature as the surface, whose emissivity and absorptivity are concerned. It is extremely unfortunate that this second formulation of Kirchhoff’s law is still presented in very many sources. While this form is also correct, it is both weak as it is and very easy to misinterpret. The error of Martin Hertzberg has clear connections to this problem.
There is also a third and original form of Kirchhoff’s law, which is even further distanced from practical applicability except as an explanation of, why cavities form black bodies. This formulation says essentially that inside a closed isothermal cavity the radiation is always black body radiation.
If we could forget about history and stick only the first more modern and most powerful formulation, we could avoid a lot of unnecessary confusion. With a proper analysis the formulations can be shown to be equivalent, but this is complicated enough to leave ample space for misrepresentation of the two latter formulations.
Direction also, that makes a difference for rough bodies.
Yes it just doesn’t work with visible light. There is another odd little footnote. Snowball Earth has the same albedo as the blue-green planet. I don’t think so.
ChiefHydrologist,
wouldn’t that depend on how much cloud there was on snowball earth? little less cloud cover should even it out quickly. Oviously doesn’t prove his statement, just leaves the possibility open.
Here is a jog for the memory:
http://www.scotese.com/lastice.htm
Kirchhoff’s 1959 and 1860 papers mainly said that for a body in thermodynamic equilibrium in an opaque cavity with only partly reflective walls, the emission is equal to the absorption, and since this depends only on the opacity and partial reflectivity of the walls, the spectrum of the enclosed radiation does not depend on which materials form the opaque and partly reflective walls. This establishes a universal radiative spectrum for the temperature of the equilibrium, though to start with we need to remember that the the universality actually stated by Kirchhoff was only universal for thermodynamic equilibrium at the given temperature and for the radiation in a cavity as specified.
As it happens, there is a wider range of conditions which are sufficient to produce the Kirchhoff law effects of this universal spectrum on emissivity and absorptivity, even when the spectrum itself does not prevail. One very important statement of a sufficient condition for Kirchhoff’s law to hold was made by Milne in 1928: the material in question is in a condition known as local thermodynamic equilibrium. This means that the rate of intermolecular collisions far exceeds the rates of creation and annihilation of photons, so that the Maxwell-Boltzmann distribution of molecular velocities holds. In the atmosphere below 50 km altitude, local thermodynamic equilibrium applies except in the interior of lightning bolts and perhaps other exceptions. Above 100 km in altitude, local thermodynamic equilibrium does not hold and Kirchhoff’s law cannot be applied in its usual form; this was explained by Milne; it is because intermolecular collisions are not frequent enough there.
The universal distribution of black body radiation does not apply directly to the radiation inside non-opaque materials such as the atmosphere. For them, however, when they are in local thermodynamic equilibrium, the black body distribution provides a so-called source function that is universal and so can be used in concert with emissivity and absorptivity quantities, and thus Kirchhoff’s law can be applied.
Kirchhoff was careful to give a precise statement of the Helmholtz reciprocity principle in his 1860 paper. Planck’s 1914 book on black body radiation makes extensive use of that principle in his proof of the universality, which is limited to thermodynamic equilibrium in a cavity with opaque and only partly reflective walls.
Typo: Kirchhoff’s 1859 and 1860 papers, not “1959 “.
Except that Hertzberg expresses it as: ( 1 – α ) /ε = 1 – where α is in this case albedo.
The adsorptance term is exclusively visible light – this is not a valid energy dynamic for planet Earth regardless of any long winded justification.
randomengineer said on February 5, 2011 at 4:09 am:
“You aren’t getting it. The WIKI article goes on to talk about wavelengths..
I don’t understand the nitpick. Not talking about wavelengths indicates that he has K Law wrong? Please. Seems to me he’s using the “general form” (integration) so as to argue something else entirely..”
Yes, I am getting it. It’s just that you don’t understand the subject.
Why is Wikipedia better than all the textbooks on the subject?
Of course, if you take Kirchhoff’s law and average over all wavelengths then yes absorptivity for all wavelengths will equal emissivity for all wavelengths. It’s a simple mathematical identity.
Does this mean that emissivity at wavelength, 0.5 um = absorptivity at 10um?
No.
It makes me think I should produce Part Two of Amazing Things we Find in Textbooks – The Real Second Law of Thermodynamics – where I scanned in pages from 6 standard textbooks to prove that hotter bodies actually absorbed radiation from colder bodies. Only to have one commenter claim that I had “cherry picked”.
Part Two of this series would demonstrate that every textbook under the sun believed that Kirchhoff’s law is that emissivity and absorptivity are equal for a given wavelength.
And of course, using dead simple maths, therefore, as a consequence, emissivity = absorptivity across a range of wavelengths. The same range of wavelengths!
Why does this mean that emissivity at 10um = absorptivity at 0.5um?
Still “No”.
Of course, a skeptic at this stage would say:
“Oh, interesting. I’ll check some textbooks. Like the one I was given the link to. I’ll check some other textbooks. And if they all state this same point, I will change my thinking and wonder why so many people unquestioningly accept obviously flawed physics as true.”
Well, that’s what a skeptic would say anyway. Many others will instead cling onto easily falsified assertions from papers because the paper claims climate science is flawed.
But I write for skeptics.
Yes, I am getting it. It’s just that you don’t understand the subject.
No, you can’t read. Nobody is saying wavelength is unimportant.
I said that Hertzberg is referring to the integrated definition, i.e. averaging of wavelengths.
But the problem he poses can’t use integrated form because the wavelengths absorbed are much different than the wavelengths emitted.
There is one thing that I don’t get and the Green Dragon is just an example.
I am not a skeptic. Like R.Lindzen said in an interview, I prefer the term denier.
If I was american, from the political point of view I would support Inhofe, R.Perry, Morano and vote republican. When Hansen makes his stunts and breaks laws, I would immediately demand that he be fired from any state financed jobs, prosecuted and put in prison.
That would make me denier squared for a “certain category of the population” I guess.
This scientifically irrelevant information being given, what I don’t get is why fellow deniers (or skeptics if they prefer) focus on the by far most UNINTERESTING aspect of the AGW theory, namely the radiation.
I reread with pleasure the Planck’s Vorlesungen at the opportunity of the Claes Johnson discussion and linked it there.
It is deep physics with elegant and clear maths and extremely accurate vocabulary. No confused numerical simulations, handwavings, vague unjustified assumptions because the computers didn’t exist yet.
Now it had been written in 1906, more than 100 years ago.
Well there was little mystery about radiation physics , black bodies and their understandig already 100 years ago.
QED gave a tool to interpret microscopical processes but in the macroscopical limit it gives the same results as what Planck and others had found out already 100+ years ago. And like Planck rightly wrote, his results can be falsified the day when Maxwell’s equations and 2nd LOT will be invalidated.
This is still not the case in 2011.
I have tried to explain with mathematics to C.Johnson that his “fight” against QM was useless because his mathematical “model” , Planck’s one (!), if it is done correctly will find the same results as QM even if using Maxwell, 2nd law and statistical thermodynamics only.
QM is not necessary to explain BB. It is just a convenient tool that expands a bit deeper beyond the limits of classical electromagnetismus. And it takes on board some other phenomenons (like photoelectrical effect) which are harder to interpret classicaly.
I am afraid that I failed.
The same is also true with M.Herzberg paper.
When I read in the first sentence : The average equilibrium temperature for all the Earth’s entities involved in its radiative balance with the Sun and Space, is given by:….
I don’t need to go to some Kirchhoff’s details to know that it will again be uninteresting.
Of course as there is no radiative balance and no “average equilibrium temperature” for the real Earth, anything that may be said after a start with such a horrible sentence will be at best irrelevant and at worst wrong.
So I still don’t get why this focus on radiation.
I think indeed that the current climate science is flawed but the holes are in the subpar primitive way it interprets the dynamics of the whole system and not in the trivial subsystem which is radiation.
Tomas, thank you for this. Again, the reason I am focusing on this is trying to get rid of all the noise surrounding the debate on radiative transfer, so that everyone can focus on the real issues associated with the complex chaotic thermodynamic/dynamic climate system. Looks like this issue isn’t going away, but hopefully the efforts here are further marginalizing those who insist on pursuing incorrect theories of radiative transfer, and alienating them from the more serious skeptics/deniers.
Judith
I said that I don’t get it.
But actually I have a theory.
It is the notion vehiculated by drawings of “radiation balances” which show a huge energy flow going from the (cold) atmosphere to the (warm) Earth.
This would be in itself not really a problem because I believe that even X or Y (no names) would admit and accept that as long as the net flow goes in the right direction, the values of the gross flows are uninteresting.
There where it hurts intuition and apparently even of scientists and physics professors is when the word “warming” is used.
Indeed this gross “backradiation” flow cannot “heat” or “warm” the Earth in any usual sense of this word.
Its size can only slow down or accelerate the cooling of the Earth but whatever its size , it is and will always be just a cooling.
So when otherwise scientifically well educated people (I think here on people like Prof. Gerlich) come in contact with definitions which are all a more or less confusing variation on the theme “The GHE is due to the warming of the Earth surface by the back radiation of atmospheric CO2 etc”, they go ballistic because they know that this is not possible.
And as they don’t read blogs, they take this definition literally instead of going in the details of “lapse rate , TOE yada yada” and write what they write.
G&T paper is an example of this approach. Actually when you read it, you realize that there is almost nothing wrong with what they say. There is not much new either. But when one comes to the end, one says “OK there are some good considerations about classical radiation , average temperatures and thermodynamics. But it has nothing to do with the atmospheric radiative transfer and the GHE definitions they falsify are all confused or inadequate.”
Actually the G&T lesson for me was to become aware how many people “define” the GHE in a completely stupid and misleading way.
Anyway it is just a theory I developped from observation of climate debates during the last 10 years or so.
But if it is true, then I would advise to AGW defenders to never ever use the words “GHE or CO2 etc heats the surface” and use instead “GHE modifies the cooling rate of the surface”.
It is just a detail but I am sure that this detail would have avoided 90% of the polemics which are only due to an incorrect and/or misunderstood use of the word “warm”.
Tomas,
G&T serves as on example in that it has few errors on science in its main text (it does contain erroneous attacks on work of others as one chapter), but presents misleading statements distributed in different places from introduction through the text to the conclusions, which is the part of the paper, which is totally wrong. The conclusions are not based on anything in the text and are indeed seriously in error in many places.
Pekka
You have been asked many times to list these” errors”.
List even one!
Bryan,
How can I show something that does not exist. The justification does not exist in the text for any of the conclusions that differ from main stream understanding. It is for you to find the connection, if you think that it exists.
Bryan,
Pekka said it “has few errors”. You seem to have misconstrued that as saying, “has a few errors”.
I have seen many people attack G&T over ‘errors’ which don’t really exist, but who completely ignore the fact that the physics presented, whilst largely correct, are irrelevant to the conclusions of the paper – which I regard as being complete nonsense, incidentally.
Bryan,
I think G&T mainly refuted sloppy explanations of the greenhouse effect and concluded from tbat erroneously the greenhouse effect doesn’t exist. They obviously never looked at books like Goody and Young and the correct definition of the greenhouse effect, which is the difference in infrared radiative energy flux at TOA compared with the outgoing energy flux at the surface. I think this is the main flaw of their paper.
Instead of pointing that out, people tried to refute G&T by stating that the sloppy explanations were actually meant in the right manner and it didn’t matter that they were imprecisely put. This is of course a poor defense for a scientist. A scientist who gets notified about imprecise wording in his book or paper should strive to correct it and be grateful for the feedback.
G&T even acknowledged the greenhouse effect, since they mention the effect of CO2 on the absorption length, which in turn leads in an atmosphere with a decreasing temperature gradient to the greenhouse effect.
And I agree with Pekka, they state mainly correct equations, but one hardly sees that their equations have any connection with falsifying the greenhouse effect.
Regards
Günter
Günter
Thanks for your post.
You make a number of points here on Judith’s site.
I think I agree with almost all of them.
About physics education here(UK) and Germany, I dont think there’s any difference.
I have access to two modern undergraduate Physics textbooks.(2000+)
The definitions of Heat, Radiative Energy, Work and so on are still the traditional ones used 40 years ago.
More generally I refer to The Feynman Lectures, Zemansky’s Heat and Thermodynamics and thermodynamics thermodynamics textbooks by C J Adkins.
All my sources express themselves using traditional definitions.
When I read the G&T paper it seemed like the traditional thermodynamics I was taught.
I could not believe the hostile reaction it received from some in the Climate Science community.
Most of the critics made little effort to understand or even read their paper.
What is the “greenhouse theory”?
There seems to be several versions.
It cant be the simple observation that CO2 and H2O radiate in the IR.
That hardly merits the grand title of an “effect”.
Some primitive adherents still cling to a glasshouse model.
This and other variants of this tropospheric centred model were demolished by G&T
For others a more advanced model involving TOA radiative accounting is proposed.
This advanced greenhouse theory I find quite plausible and perhaps G&T might too.
Certainly I can see how attractive it is to you.
Being an experimental Physicist the simplicity of the measurements and their accurate determination are very appealing .
Regards
Bryan
Bryan,
Thanks for your comment and the clarification. I think I have to apologize to English textbook and I have to say that I would never doubt the education on English universities.
I actually went back to my bookshelf and only encountered in one of them an ambiguous definition. So I have to apologize for cherry picking.
About G&T, I had the same impression as you had. The critics did not try to engage in a scientific discussion and I guess never tried to understand. However, I think G&T never tried to understand their critics either. However, I do think one can work through the paper and learn from it a lot. I found their paper very useful.
From the discussion in the blogosphere and even in literature one can also learn a lot about the scientific debate about climate change and within climate science. The climate seems to be biased and poisoned so to speak.
For the definition of the greenhouse effect, I prefer the following from my textbook Bergmann-Schaefer : Lehrbuch der Experimentalphysik Vol. 7 Earth and Planets.
It says: “The planetary greenhouse effect is the experimental observation that the equivalent radiative equilibrium temperature of a terrestrial planet is smaller than its surface temperature.”
I prefer this definition, since it is based on experimental observations.
I also like the definition of Thomas and Stamnes in their book: Radiative transfer in the atmosphere and ocean: They define the greenhouse effect as the difference in outgoing surface and TOA fluxes.
I do not think it appropriate to label something greenhouse theory. I think the greenhouse effect is an experimental observation and one can use radiative transfer theory to explain this observation perfectly well.
There is my critic of G&T. They identified poor explanations with something they called greenhouse effect or even greenhouse theory. Before putting their paper out and calling it: Falsification of the greenhouse effect, they should have thoroughly screened the literature and learned what is actually meant with “planetary greenhouse effect” within climate science.
Regards
Günter
Tomas, I agree that the semantics of communicating this to the public leaves much to be improved upon. CO2 emissions modifies the net radiation balance at the surface. At night (in the absence of solar radiation), the net energy loss from the surface is reduced by the infrared emission from CO2, H2O (and clouds, if they are present). I think that is the correct way to express it in words, in a way that is unambiguous. But you have to have some base level of physics understanding for such a statement to make sense.
As I have been posting in Part III, it is the change in back radiation (due to increasing CO2) that causes warming in the equilibrium state, just as changes in solar radiation can cause warming or cooling. People often miss the importance of the time derivative when referring to slowly changing equilibrium states.
Hey, I must have some base level of physics understanding because I find nothing objectionable in Judith’s summary. The only thing I would add is the CO2 effect is immeasurably small.
Judith the energy yo are referring is energy already present in the system. It does not matter if it is being passed around by water vapour, CO2, O2 or N2, it does nothing to increase the net energy of the system.
In general IR is outgoing energy. If CO2 absorbs and emits this energy adding more CO2 just means more absorption and emission, the is not the same as increase in net or anything like it.
The only way to increase net energy is to increase incoming energy. The only place were that increase could be stored is in the oceans, not the atmosphere.
Adding more CO2 to the atmosphere according to “greenhouse” theory can only increase overall emission to space.
The “greenhouse effect” hypothesis is as self defeating as any other fallacy.
Yes, the energy is already there, extra CO2 only delays the escape of the energy to space, thereby heating the surface, atmosphere, and ocean.
No it does not, this is a circular argument.
It may be a circular arguement, but it doesn’t violate the first law of thermodynamics like your arguement does.
If the energy takes longer to escape, then there is more of it, therefore it is warmer.
bobdroege,
then you statement is that any additional energy in the earth system raises its temperature.
Judith the energy yo are referring is energy already present in the system. It does not matter if it is being passed around by water vapour, CO2, O2 or N2, it does nothing to increase the net energy of the system.
Really, like the PDO, AMO etc?
AMEN!!!!
(That was directed to Thomas, who I agree with on virtually everything).
Thanks Tomas,
I agree. It is also my impression that a lot of debate could have been avoided if the words heat, energy or heat radiation had been used more precisely and not as synonyms as was done in Germany by Rahmstorf and Schellnhuber in their Booklet: “Der Klimawandel”. Therefore, I do also think that it might not be a coincidence that G&T have written this paper, since my german textbooks are using heat and energy more precisely than my english ones. I wouldn’t have passed my final exam at the university, if I had confused energy, heat and radiation as Rahmstorf and Schellnhuber did.
Regards
Günter
Tomas
In 1896 Arrhenius published his theory. In 1907 in a much less quoted paper he drastically revised his estimates downards. Would he have known about or been influenced by Planck’s Vorlesungen?
tonyb
Tomas Milanovic,
Thank you so much for laying out your view of current physics and it’s understanding throughout this comment and further comments to comments for I could never have said it so perfectly clear.
Thanks again. I agree!
The flaw is merely in the logical layer. The average knowledge within some 100 random physics books I always find is correct, the library has shelves of them; the average knowledge emanating from some 100 randomly picked “climate experts” in today’s “climate science” is not, and the flaws always seem to home right here on this topic, radiation. I could vent my anger toward them and what they have done to science and particularly physics right here but I’ll refrain for now.
Eli is not sure of that. The limitation imposed by QM from the solution to the harmonic oscillator is that the minimum energy excited state of an oscillator of frequency ν is hν. This means that for ν large enough the upper state will not be populated (my suspicion is that you only need this, not so much that the other allowed energy levels are nhν). If you don’t have that, you have to impose some sort of minimum energy of the excited oscillator ad hoc.
However, to answer your second question, in post normal science anything goes.
I’m glad Tomas Milanovic and Guenter Hess (on the discussion thread) brought up the misuse of the word Heat when used in a technical discussion.
Science Of Doom is a serial offender in this regard.
A quick look over some of his topics gives several examples of a colder surface apparently heating a warmer surface.
Despite my suggestion that he should stop this misleading habit he persists.
However he now puts “heat” in quotation marks and has a footnote to say that “heat” does not mean heat.
He considers this a “dull point” and appears to resent my bringing it to his attention.
At times I wonder if this misuse of the word and hence the implied wrong direction of heat flow is necessary element in the greenhouse theory.
I am reassured by defenders of the IPCC position and can explain their point of view without appearing to violate the second law of thermodynamics .
Bryan:
“At times I wonder if this misuse of the word and hence the implied wrong direction of heat flow is necessary element in the greenhouse theory.”
It’s hard, at least for me, to look at the KT radation cartoon and not “see” that it is showing a heating of the surface by the colder air. That diagram is a source of a lot of confusion, I think. Thomas and many others have explained the heat/radiation flow correctly, but those diagrams and certain misinformed people confuse things.
The statement that Thomas made that I really think is on-target is this one:
“So I still don’t get why this focus on radiation.
I think indeed that the current climate science is flawed but the holes are in the subpar primitive way it interprets the dynamics of the whole system and not in the trivial subsystem which is radiation.”
The KT type diagrams show the atmosphere to be a source for IR going in all directions. Any other cartoon would be misleading if it did not show the atmosphere as a source of IR, and that does include the NASA Figure 4 from this book which only shows net IR flow between the ground and atmosphere which should strictly be two separate flows.
I agree that any discussion of radiation is a distraction. To me, radiation between objects with similar temperatures is a natural phenomena…it might be interesting, but you can’t do anything with it and it certainly doesn’t do much. If there are materials with mass and delta-T, then there will be radiation, who cares? I’m fully aware we get everything we love in life from solar radiation and radiation gets significant when delta-T is huge or in a vacuum when radiation is the only game in town.
I will say this very clearly. Suppose my boss came to me one day and said, “Ken, the job is to raise the temperature of this gallon of water by 25C.” If I started telling him the best, most cost-effective method has anything to do with radiation…well, I’d be looking for a new job very soon…after the boss laughed at me and kicked the seat of my pants.
So, what lesson shall we take from this? If one of our favorite climate scientists is looking for a job as an electrical engineer, I suggest they forget everything they know about radiation and don’t bring it up during the interview.
Ken,
I interpret your message to mean that you accept the words of others, but invert their meaning.
Others are saying, that even skeptics should accept the radiative effects and their significance, but you imply that they are not important.
I’m saying: whatever effect you think rarefied atmospheric CO2 has, it is immeasurably small. I’m saying there are many things that are interesting about thermodynamics, but not in cold, rarefied gases which have little thermal mass and little thermal capacity.
I’m saying that one of the most interesting and important engineering challenges of our generation is storing energy so you can disconnect the time it is generated from when people want to use it. If I believed, like you, in the huge control CO2 has over huge amounts of energy and its ability to be discharged to space over long periods of time, then CO2 would be very interesting in solving real world problems. But, it’s not. Why are vacuums, Argon or Krypton used in insulating windows…and not the all-powerful, amazing insulating energy translator CO2?
Good grief…I’m glad engineers rule the world and not academics.
So you are denying perfectly well known physical facts.
Okay, Pekka, whatever you say. I got to where I am today in spite of large misunderstandings in thermodynamics. Fine.
The real question is…when we talk to uneducated Joe Public about our ideas…and you want him to change his lifestyle and pay for expensive government programs based on human-modulation of our radiative balance–and I share my thoughts on how well things with small thermal masses and low temperatures affect the earth’s surface temperature…who will Joe believe?
I suggest you work on your elevator pitch, Pekka.
Ken
I have written numerous messages related to these further issues.
Many participants of these discussions have expressed hope that the best known part could finally be left behind and the discussion proceed to the more open and very important issues. That was said also in the comments, whose meaning you reversed.
There will always be people who continue to deny even the certain part of science and there will be others who try to increase their number by their writings. We cannot but live with that.
Pekka,
Run out of reply space at the original reply location, so here is my response:
Pekka Pirilä | February 9, 2011 at 9:09 am |
What is the mass of 0.039% of CO2?
“Irrelevant question.” Can you elaborate?
How much IR energy can 0.039% of CO2 can absorb at 15 um wavelength?
All of it and many times on the way up through the atmosphere as it also emitted many times.
What is the specific heat capacity of CO2?
“Irrelevant, because heat is shared efficiently by all gas in the atmosphere.” How much IR radiation transfer heat from the Earth surface is shared with the atmosphere gases? What is the share of CO2?
If we assume the solid mass of the Earth surfaces do not exist, just 10m deep of ocean water exist, discounting the reflections, how much energy the water absorb from the whole light spectrum from uv to IR and how much IR energy from the 0.039% CO2 15 um wavelength in the atmosphere?
“Oceans absorb more than 90% of solar radiation that reaches it, but not all in the top 10 meters as light penetrates to a significant extent deeper. Oceans absorb very close to all IR that reaches its surface and this happens in a very thin skin layer (the same layer that also emits IR and more of it than it receives).” How thin is the skin? How much IR energy this thin skin emits? How much that 0.039% CO2 in the atmosphere absorb this thin skin’s IR radiation?
Sam,
The mass is irrelevant, because no significant effect in atmosphere is influenced by this mass. CO2 is important only, because it absorbs and emit radiation and transfers energy efficiently between this radiation and the local thermal energy of the atmosphere.
The thin skin that IR radiation can penetrate is about 1 mm thick or thinner depending on wavelength. The emission is typically 400 W/m^2 and incoming radiation 340 W/m^2. Thus the average net flux is about 57 W/m^2.
Most of the emitted radiation is absorbed in the atmosphere, where water vapor has the largest effect as it influences a wide range of wavelengths. CO2 is very effective around 15 um, which is a very important part of the radiation, but less than 20% of all IR. The amount of CO2 influences the range of the wavelengths absorbed effectively. Little CO2 is enough near the center of absorption peaks, but adding more CO2 has an important effect at he edge of the absorption band. This is the basis for the estimates of the strength of the warming effect (additional radiative forcing).
Pekka,
“The mass is irrelevant, because no significant effect in atmosphere is influenced by this mass. ”
If mass is irelevant then the increase of 280ppm to 390ppm CO2 in atmosphere in warming the atmosphere is irrelevant. CO2 is only efficient at 15 um is minimal IR energy or trivial energy compared with the whole spectrum of IR radiation and IR radiation from atmospheric gases is trivial compared with IR radiation from the whole Earth surfaces.
“The thin skin that IR radiation can penetrate is about 1 mm thick or thinner depending on wavelength. The emission is typically 400 W/m^2 and incoming radiation 340 W/m^2. Thus the average net flux is about 57 W/m^2.”
1mm thick, how did you get that? Please elaborate.
400 W/m2 water surface skin radiation heat, how did you get that? Please elaborate.
How did you get the average net flux of 57W/m2 from the atmosphere? How much of that 57W/m2 radiation (or heat) flux comes from the 15 um of that 0.039% of CO2 against the whole spectrum of IR radiation from the atmospheric IR radiation?
Sam,
Of course the amount of CO2 can be expressed as concentration in units of ppm and as mass, but switching from one that is commonly used (ppm) to another (mass) gives no extra value. I cannot avoid thinking that you are searching for a argument, but all arguments that I can imagine are wrong and totally misleading. There is nothing obvious to learn from the mass, that is not known better from other considerations. If you explain, why you ask for this number, then I may be able to tell something more.
The thickness of the skin, where the absorption and emission occur is from literature
http://disc.sci.gsfc.nasa.gov/oceans/additional/science-focus/modis/MODIS_and_AIRS_SST_comp.shtml
The source for the fluxes is Trenberth, Fasullo and Kiehl. The numbers are not known with high accuracy, but these numbers give certainly a good general view on, what is going on.
I am not going to check precise values for the share of the radiation within the 15 um absorption/emission band of CO2. I told that it is less than 20% of all IR, but I leave it to that even if the correct value may be significantly less. Actually it is not possible to state very precisely, where the limits of the band are, but that is not a big problem as the actual physics can be calculated anyway.
Pekka,
No, mass of CO2, mass of atmosphere gases and mass of the Earth give you same base to compare with radiation energy.
No, Pekka, I seek clarification of radiation misconcepts , not seeking arguments which waste time.
You are not rigorous as someone had already mentioned Climate Science needs to be rigorous with your following comments:
“The source for the fluxes is Trenberth, Fasullo and Kiehl. The numbers are not known with high accuracy, but these numbers give certainly a good general view on, what is going on.
I am not going to check precise values for the share of the radiation within the 15 um absorption/emission band of CO2. I told that it is less than 20% of all IR, but I leave it to that even if the correct value may be significantly less. Actually it is not possible to state very precisely, where the limits of the band are, but that is not a big problem as the actual physics can be calculated anyway.”
You did not seek clarification of the 57W/m2 from
Trenberth, Fasullo and Kiehl and you did not care how much 0.039% CO2 at 15 um contributed to that 57W/m2!
Sam,
What is your motive in presenting questions, when you seem to believe that you know better?
Pekka,
“I am not going to check precise values for the share of the radiation within the 15 um absorption/emission band of CO2. I told that it is less than 20% of all IR, but I leave it to that even if the correct value may be significantly less.”
May I conclude that you don’t know?
Sam,
May I conclude that I doubt your honesty?
What if I have a microwave and you have a stove and the gallon of water is in a plastic jug and you don’t have a pan, and what if your job depended on it.
I’m glad my opinion of engineers has nothing to do with what the majority of them say on climate related blogs, they don’t seem to get it.
That’s an excellent and intelligent comment, bobreoege. Thank you. There’s no question about it, if you want to generate -4,000VDC@4A and focus 2.45Ghz beams from a magnetron tube onto the gallon of water, it would easily give a 25C rise. Well done, sir.
For suggesting it, I’d still be fired, but the boss might not kick me in the rear. He’d still laugh.
Now, to draw this topic back to climate science, I’d love to hear your thoughts on using radiation from a passive body to add heat energy to (or modulate cooling efficiency of) an active source.
Ken,
it seems, from your comments, that you can ignore radiative heat transfers in your job.
fine.
I do not see how this tells anything about heat transfers in the atmosphere. Above the troposphere, there is not much vertical mixing. convection can thus be ignored. Maybe you want to argue that conduction is more important than radiation, in thin gas?
BTW, as an electrical engineer, I can not believe you never have designed a radiative heater. They are everywhere, and often electrically powered. The grill in a oven, infrared heaters in bathrooms, public places (there it is often gas powered), everywhere. How do you think they work? can not be convection, they are ABOVE the stuff to heat. If you try to explain to your boss they work by conduction, I hope you have padded pants…because the kick is coming fast….
Most designs I work on has a thermal problem, but its how to keep a semiconductor die cool. We got heat and we need to get rid of it. Radiation does me little good with this problem. I am comfortable with active sources to create radiation…I’m no expert, but I’m not going to make large mistakes. I have friends with the same heat problem, but their designs must work in space, so they are stuck with conducting to large radiating surfaces…this is a tough problem. How they wish they had some air flow to help them out.
The biggest problem is radiation from passive sources. I don’t think you’ll get much use for anything coming from a passive source. I’ve enjoyed the radiation from a brick wall after the sun goes down, but that radiation comes from heat energy stored in materials with large thermal masses, which meter the radiation and slowly emits it when the air cools. Fine. What heat energy are you getting from a passive, rarefied gas? You gonna use that to heat water or do anything useful? I thinketh not.
Oops, more fractured prose. Sorry.
Ken wrote: “its how to keep a semiconductor die cool. We got heat and we need to get rid of it. Radiation does me little good with this problem”.
Really? Do you know the reason why good CPU heat sinks are painted/anodized into black?
Then you ask: “I don’t think you’ll get much use for anything coming from a passive source… What heat energy are you getting from a passive object”.
It is strange you ask. It is the same energy that heats your die. The thing is called “thermal resistance”, ever heard of such thing in engineering? Ever heard of Dewar Flask? Or attic insulation? I think you are making substantial mistakes in your designs, and your boss should fire you right away.
Al,
they tried black paint on air cooled motorcycle engines. Net wasn’t enough to make the cost of the paint worthwhile. Without airflow cooling is tough especially for electronic components.
Great, Al. Let’s imagine I am trying to cool a semiconductor device, but like all practical designs, it is surrounded by other hot devices. Now, my friend, in this situation, how smart would I be in assuming I have radiation to count on for lowering my die temperature…when it’s possible the device is actually absorbing radiation, not emitting it?
You’re right that metal heat sinks have a thin emissive coating, but it’s something to be careful about, because any coating that insulates works against desperately-needed convection which is far more effective at lowering thermal Z.
Ken, to prevent a part of design from absorbing ambient radiation and corresponding overheating, you put a radiant shield. Before you were born, there were electronic devices built from vacuum tubes. It was a customary practice to place polished metal plates between red-hot tubes of output power stages and other thermally-sensitive circuitry.
For that, I would have to know what you mean by passive and active radiation sources.
Sounds like techno-babble to me.
Or how is the earth’s surface and the atmosphere different in regards to their being radiation sources?
Seems clear enough to me. An active source is one with an internal heater (like the sun) or a bowling ball with a heater embedded inside. A passive source is heated only by external radiation (like the moon). CO2 is stimulated by incoming IR insolation, but generally we ignore that. Does an atmospheric CO2 molecule have an internal heat source or thermal mass so it can store heat energy? No? Let’s call it passive then.
Oh yes, atmospheric CO2 molecules do have “heat source”. It is called “buffer gas” of N2 and O2 that has certain temperature. Temperature is temperature regardless of how a macroscopic body has acquired its energy, via an electric heater, or radiation, or laser tuned to other trace molecules, or a hammer. The last source (hammer) might be instrumental to understand that the entire distinction of Claes Johnson between “high frequencies” and “cut-off frequencies” has no grounds: all electromagnetic waves have the same nature, and there is no “high enough” or “low” temperatures in order to emit (other than near absolute zero), it is just a matter of energy of EM waves.
Sure, Al, that’s good. I’m glad we finally agree on something…i.e., that N2 and O2 have a temperature and exchanges occur between all the gases. The earth and water heats the atmosphere via conduction and this heat energy is moved around with convection. The question is, can this energy, which came from the earth’s surface, couple to CO2 and WV and radiate back to the earth to make it hotter than it was?
I think we all agree that the rate of cooling can be modulated, but that’s not what Joe Sixpack was told. Joe Sixpack was told that peak temperatures are going up, new records are being broken, we’re flirting with disaster and we need to close coal-fired death plants and drive hybrid cars immediately.
induction heating use it all the time to melt refractory materials.
Bunnie!!!!
Induction heating of the atmosphere?? Sounds like Electric Universe theory. Cool!! 8>)
Yep, you can do that.
I would suppose also that your engineer has no interest in climate science, because you just can’t get anywhere without understanding it. The radiative balance at the top of the atmosphere is the fundamental boundary condition that constrains the climate of all Earth-like planets, it is crucial to understand how climate can change in time, and is now an key aspect in observational analysis of our atmosphere (through radar and satellites).
You got it, Chris. I would never in a million years look at radiation, which is caused by delta-T between things with mass…and think to myself…hot dog, I’ll modulate the radiation and control the temperatures of those bodies. You have to be a climate scientist to believe things like that.
Ken, it is rapidly becoming clear that your education in physics has never surpassed a high school class. I guess if we doubled the intensity of the sun, it wouldn’t matter much? Pots of water or people sitting around a fire don’t get heated through radiation? The Earth doesn’t lose some 1.23*10^17 Joules of energy every second, and reducing the rate of this heat loss would not warm the system? Only a politician would believe things like that.
Here, Chris, for your benefit, I will repeat what I said above.
I’m fully aware we get everything we love in life from solar radiation and radiation gets significant when delta-T is huge or in a vacuum when radiation is the only game in town.
I’m disappointed. Based on a jcurry comment, I figured I had a good base in physics, but now I’m back to the high school level. Bummer. I suppose I should write to my college professors and let them know they really blew it when they gave me good grades.
chris,
On the contrary, Ken appears to be well versed and you did not pay attention at all. If I were your lecturer, you got F and Ken got A.
Thank you, Sam, I appreciate that. I am an engineer and I did well in my science classes, including physics. I confess, I’m not so good at the metaphysics that Chris likes so much.
Free book for you…no, make it two free books, I’ll give you a signed copy of The Hockey Stick Illusion too. E-mail me your address and I’ll take care of it.
Thank you for your offers. I don’t know your e-mail address and I don’t want my e-mail address to be bombarded with all sorts of spams if I expose my e-mail address here though I appreciate all posters/authors here are all civil, well educated with dignity.
Sam, If you wish to keep your email address private and get in touch with Ken then write a comment to me at Suite101 with your email address in it and I’ll forward to Ken ( all comments to me on Suite101 remain unpublished until I permit it).
http://www.suite101.com/profile.cfm/johnosullivan
Chris,
let me make a comment here, since your post is an excellent example. You give generally excellent comments about the science of the atmosphere and I usually learn something from it. Thank you for that.
However, I do not know what your profession is, but It is not a good style and good manners for a scientist to doubt the education of other people, based on a few sentences in a blog. We are discussing about scientific topics here with different areas of expertise. Scientists should engage in arguments and learn from each other arguments. Even if the arguments are wrong a scientist can learn from it. If somebody posts an incorrect sentence or an incorrect argument about science, one can mention that and ask for a clarification. A scientific debate is never a contest who is right or wrong, but rather an engaged dialog to learn something about the scientific topic together.
I appreciate this blog by Prof. Curry, since it is much better than other blogs in this respect.
I would encourage you not to diminish your worthy contributions by “ad hominem” attacks on others.
Best Regards
Günter
Guenter, well said. It appears to me that Dr. Curry ought to insist on high standards more often in the published commentary as throwing insults around can too easily lead to libel and we can all do without lawsuits, surely.
John,
I agree. But I think we should do it also more often as a kind of peer review. It could be a selfregulating mechanism. Judith cannot be the watchdog for everybody on the blog.
Regards
Günter
Unfortunately I have noticed that requirements for politeness are misused by those who do their best to spread falsehoods and even lies under assumed protection through an overly polite formulation of the messages.
Politeness cannot be construed to mean that falsehoods could not be stated unambiguously as falsehoods and lies as lies or that people who try actively and purposefully spread falsehoods or lies should not be exposed.
Ken,
It would be worth your time to look at the Standard Model and what it says about photons, what radiation is made of, and how many degrees of freedom photons have, which is three.
Two for the direction the photon is traveling and one for its wavelenth, which leaves no room for anymore information, such as what temperature the object that emitted it was, or anything else.
Energy is everything in climate change. All planetary warming or cooling occurs because there is a difference between incoming and outgoing energy, an energy imbalance. The imbalance results in changes to the amount of energy stored, mostly as heat in the atmosphere and oceans, in Earth’s climate system. If more energy enters the atmosphere from the Sun than is radiated as heat or reflected as light back out into space – the planet warms. Conversely, if less energy enters the atmosphere than leaves – the planet cools.
If this discussion is reframed around the 1st law of thermodynamics rather than Kirschoff – Earth’s energy budget can be completely defined in 3 terms. Energy in less energy out is equal to the change in energy stored mostly as heat in the oceans and atmosphere.
To repeat myself – this can be expressed as:
EIN/s – EOUT/s = d(GES)/dt.
By the law of conservation of energy – the average unit energy in (Ein/s) at the top of atmosphere (TOA) in a period less the average unit energy out (Eout/s) is equal to the rate of change (d(GES)/dt) in global energy storage (GES). The most commonly used unit of energy is Joules. Energy in and energy out is most commonly reported in Watts (or Watts/m2) – and is more properly understood to be a radiative flux or a flow of energy. A flux of one Watt for one second is one Joule – which is known as unit energy. Most of the stored energy is stored as heat in the oceans which is measured in Joules (or Joules/ m2).
Is this interesting or useful? I maintain that it is. If we look at the period 1990 to 2000 – we know that the planet warmed in both oceans and atmosphere and that, therefore, energy in was greater than energy out. Having chosen the period carefully, solar irradiance varied from peak to peak in solar cycles but with no net increase or decrease. (The absolute value is questionable – has indeed been adjusted down recently – but the differences, in both inward and outward flux, are known much more precisely.)
So the increase in planetary heat content occurred as a result of less outward radiative flux – as predicted by AGW theory.
Actually, I am being a bit mischievous. ISCCP-FD and ERBS data agree, within reasonable limits, on both the quantum and trend in upward LW and SW radiative flux anomalies at TOA. NASA/GISS insist that these results are now robust.
The trend was to quite substantially less reflected shortwave between 1984 and 2000 as a result of less global cloud cover. The trend in LW was to strongly increased emissions over the same period.
I maintain that the physical evidence, by observation and inference, for decadal changes in low level marine cloud as a result of changes in sea surface temperature in the Pacific multi-decadal pattern is very strong. The persistent patterns of Pacific variability show up, of course, in global hydrological variability as well.
There are 2 papers – a review of Pacific Ocean science and the simple energy model – here – http://www.earthandocean.robertellison.com.au/ – both of which have been submitted for publication so keep it to ourselves.
To bring in the chaos thread – this doesn’t mean that there is no climate risk in anthropogenic greenhouse gas emissions. In chaotic system such as Earth’s climate undoubtedly is – these small changes can accumulate until they trigger an abrupt shift that is wildly out of proportion to the initial impetus. To quantify the risk – we would need something like Tim Palmer’s Lorenzian Meteorological Office. However, there seems not much doubt that a range (a probability density function) of climate risks exist as a result of anthropogenic greenhouse gas emissions.
I propose that the collapse of the probability function leads to many climates in alternate universes – the many climates interpretation. No – only joking.
Chief Hydrologist,
“If more energy enters the atmosphere from the Sun than is radiated as heat or reflected as light back out into space – the planet warms. Conversely, if less energy enters the atmosphere than leaves – the planet cools.
If this discussion is reframed around the 1st law of thermodynamics rather than Kirschoff – Earth’s energy budget can be completely defined in 3 terms. Energy in less energy out is equal to the change in energy stored mostly as heat in the oceans and atmosphere.
To repeat myself – this can be expressed as:
EIN/s – EOUT/s = d(GES)/dt.”
This is an incorrect assumption. The oceans store energy mostly because they are insulated by the air above. The atmosphere is not an energy store. It is cooling fluid. It has no insulator above it. It holds energy for a fraction of the time of the oceans and does so only while transporting it away from the surface.
The atmosphere is an energy transport mechanism which has an overall cooling effect. Its main function is the removal of energy not the storage of energy. In performing this task the overall effect is cooler daytime temps and warmer nighttime.
Thats it.
There is no such thing as a substance that traps in heat, NONE.
Increasing radiative transmission of air by adding more CO2 decreases insulation. This means more CO2 = cooling.
The oceans can store energy and the biosphere and geological processes can lock energy away sometimes indefinitely, but the atmosphere is not a store of energy. It is a transport mechanism which performs an overall cooling function.
But another way to state the first law of thermodynamics is to state that the change in internal energy of a system is equal to the heat flow into or out of the system minus the work done on the system.
U = Q – W
Which means you can transfer heat to something either by heating it or doing work on it, which means you can trap heat.
No, it means you can transfer energy, it doesn’t mean you can trap heat. A Thermos is about the best we have for trapping heat.
A free flowing fluid is probably the worst.
Right! And keep in mind the earth is like the content of the thermos because we are surrounded by the vacuum of space.
Ken,
you are not helping!
A Thermos employs a reflective surface to block radiation. The vacuum merely prevents conduction/convection. Nobody claims that the atmosphere cools to to space by either of these processes.
The only energy transmission process that cools the atmosphere to space is radiation. How is this anything like a Thermos?
Sorry, Will. I’m trying to help.
Here’s my point (using an electrical analogy):
If you’re defining thermal resistances between point A and point B and you know there are two resistors and one (R1) has a high resistance, say 10Mohm–and you’re not sure what the other one (R2) is, but you know its likely between 100 and 200 ohms. Guess what, it doesn’t really matter what R2 is. It’s irrelevant to the total resistance and if you’re changing the value of R2 in an attempt to modulate the current through R1, you’re wasting your time.
So, who cares what the changing radiation properties of CO2 are, it’s in series with space.
From the thermos design problem, it’s true that they use a low-emission coating, but only because its cheap to do and helps a little bit. The main design goal is met by the quality of the vacuum and minimization of a direct conduction path to the outside (in the support structure of the vacuum flask).
Ken,
The reason they use a reflective coating is because without it, the vacuum alone is inefficient. Even with the vacuum and the reflective coating, a Thermos is only effective for a short time.
But the point I was making is that no substance, especially fluids and gases trap in heat.
As I keep saying, adding more CO2 can only reduce the resistance of energy transmission in the atmosphere because air is a poor conductor. Therefor increasing the emissive properties of air lowers the overall resistance regarding energy transfer and increases the transmission to space via radiation, which is the only process by which energy is lost to space.
Through repetition, I remain optimistic that eventually the penny will drop.
Will, you say:
“adding more CO2 can only reduce the resistance of energy transmission in the atmosphere because air is a poor conductor. Therefor increasing the emissive properties of air lowers the overall resistance regarding energy transfer and increases the transmission to space via radiation”
So, according to you, adding more ink to a glass of water increases glass’s ability to transfer light. Maybe you need to reconsider your statement?
Regarding thermal conductivity of air, maybe you need to take into account something else, say, the turbulent convective stirring? [ which makes the heat transfer across atmosphere about 100X more efficient than across a slab of copper].
No, it means that heat and energy are the same thing, that is what the first law of thermodynamics is saying.
Well said, Will. You’re talking a lot of sense as per usual.
Thanks John.
In the thread of part 1 there were quite a few people trying to claim that O2 and N2 do not absorb or emit IR. Only CO2 and other “greenhouse gases” absorb and emit IR was their position.
Even if that were remotely true, it is a self defeating argument for the so called “greenhouse effect” because increasing CO2 would increase the ability of the atmosphere to emit IR into space.
It is of course a fallacious argument. How can increasing the ratio of gases which emit cause atmospheric warming?
Which ever way you try and spin it, more CO2 means more IR emission to space.
Will
Sound logic.
I heard it many times in college, in the context, “How can beer make me drunk? Beer is a diuretic; the more you consume, the more alcohol is carried away by natural bodily functions.”
Oh.
Wait.
That argument never worked against breathalizers and hangovers.
Somehow I don’t think many politicians making policy decisions for the future of humanity will be instilled with much confidence from such arguments.
Still when you’re running out of ideas and politicians around the world are walking away from the issue because they can already see the writing on the wall, anything is worth a try.
Will
Many of the people making those arguments in college are now politicians.
Some of them are making breathalizer-beating arguments still. Probably not a few this very night.
When you see a friend making such an argument, you take away his keys.
Not all of the IR kinetic energy absorbed by the CO2 and H20 is re-emitted. Some of it is transfered to other gas molecules through collisions.
And that increase net energy, how?
When a greenhouse gas molecule abosrbs a photon of thermal radiation from the earth’s surface and transfers that energy to another molecule via collisions, that quanta of radiation does not escape into space as it would if the greenhouse gas were not present. By simple accounting, net energy lost is reduced, therefore net energy retained is increased.
Sorry, David, that’s utter garbage and simple empirical proof shows us that the s0-called runaway greenhouse effect you allude to has never been evidenced (even when the geological record shows atmospheric concentrations of CO2 were at 7,000 ppm ) making today’s 390ppm positively puny). The atmosphere acts as a cooling mechanism not a heating one and all such radiation is readily transported out into space as per this equation:
IN = OUT or BOOM!
It is not a “runaway” greenhouse effect; it is the greenhouse effect. I have made no statement on whether increased CO2 is causing climate changes. But there is a greenhouse effect and CO2 is a greenhouse gas. Perhaps you could isolate which basic point is “garbage,” so I can help you.
1. CO2 absorbs energy in the IR spectrum.
2. Gases thermally equilibrate through collisions.
David,
the flux of energy from the lower atmosphere to the higher layers changes in response to changes in the greenhouse effect close to the surface of the earth. When more IR light is absorbed by GHG’s close to the surface and thermalization occurs with the other non-IR absorbing molecules, less of that ‘earthlight’ can reach upper layers of the atmosphere and so we see an inverse effect. The stratosphere should cool because the energy balance is changing due to less incident earthlight reaching those layers.
The net energy is always the same. The energy can get stratified into the different layers of the atmosphere differently, which is what a dynamic greenhouse effect theoretically does.
But even the energy ‘trapped’ by GHG’s eventually gets released back to via help from convection and condensation processes.
The net energy is always the same as what? Energy is released to space at a slower rate with GHGs in the atmosphere than without. Even if the energy takes 1 microsecond to reach space instead of leaving at the speed of light, you have increased net energy.
What joy it is to witness fools tie themselves up in knots with their pseudo science drivel.
I hope these days never end.
The fact that you are resorting to name-calling and not directly stating your dispute with what I’ve written speask volumes.
One rule for you, another for every one else.
Again, what’s wrong with what I wrote?
David,
‘The net energy is always the same as what?’
The net energy in the climate system is the same value, zero, all the time. Although the mechanisms of energy dissipation are interplaying differently.
‘Energy is released to space at a slower rate with GHGs in the atmosphere than without.’
No, energy is released from the lower portions of the atmosphere at a slower rate, which causes the temperature of the lower portions of the atmosphere to increase.
Fred seems to have there is an alternative explanation as to why the upper reaches of the atmosphere cool in such a situation, but the base fact is that it’s not the net energy in the climate system that changes. It’s the energy DIFFERENCE between the stratified layers of the atmosphere that is changing. Depending on the magnitude of this difference, some researchers have claimed there is a clear cut signature of a CO2 forced increase in the greenhouse effect.
Because the energy difference is larger, it means convection should be stronger, due to the 2nd law of thermodynamics, but I’m not sure we’ve seen the consequence of that yet.
In either case, when dealing with these nuts (Will and John), it’s important to identify when the main physical response will be. It will not be an increase in the net energy in the climate system. It will be changes in the stratification of energy through the climate system.
Maxwell – the mechanism of CO2- mediated stratospheric cooling is described on page 332 of Dennis Hartmann’s “Global Physical Climatology”, and in Chapter 4 of Pierrehumbert’s new book.
I may be misusing the term “net” as it is understood here. I’m speaking of the “net” change in the internal energy of the earth/atmosphere system, which is obviously not zero and can change. Sorry for adding to any confusion. I’m not making a statement about climate change or surface temperatures or where the increased internal energy would be stored or which particular greenhouse gas is a villian, because I don’t think any of that is required to explain the basic physics that is being called into question in these threads.
David,
‘I’m speaking of the “net” change in the internal energy of the earth/atmosphere system, which is obviously not zero and can change.’
Under the steady state approximation, which is invoked extensively in this discussion, in thermal equilibrium, the amount of energy absorbed and emitted by the earth is the same. Therefore, the net internal energy change over time is zero.
Now, changing the magnitude of the greenhouse forcing changes the internal state of the system, but if we assume that the radiative changes necessary to move to a thermal equilibrium happen very fast, as you have, then, again, because we are in a ‘new’ steady state thermal equilibrium, the net energy balance is zero yet again. That just comes from the definitions of steady state and thermal equilibrium
I think when you say ‘the internal energy of the earth/atmosphere system’ you are really talking about the portions of the atmosphere that we interact with (ie the lower portions of the atmosphere). If that is the case, then I agree with you. Standing on their own, the temperature of these portions of the atmosphere will increase.
Taking the whole atmosphere into account, however, if we are assuming that transient effects have a negligible period, the net change in the internal energy of the earth’s entire climate system must be zero. By definition.
I think there is a language barrier in this conversation, but it’s nothing we can’t handle.
I think it may be more than a language barrier, but let’s see: A permanent change in the magnitude of the greenhouse effect is not a transient. If the magnitude changes permanently the total Earth system will find a new equlibrium steady state at a higher or lower internal energy.
As a further display of my ignorance, I think the parts of the atmospheric state that are not reset every night are certainly reset in the winter. Gases and vapors simply do not have long thermal time constants. Heat energy does not accumulate like compounded interest. In fact, even compounded interest doesn’t help you much if your bank balance is often reset to zero.
Maxwell – The view that CO2 cools the stratosphere because it reduces the IR flux into the stratosphere is commonly expressed, but it is incorrect. In fact, during CO2 radiative forcing, IR flux rising into the stratosphere from the troposphere actually increases. This is because the troposphere is warmer, and flux in all directions increases with temperature.
The actual explanation resides in the fact that much stratospheric warming is due to absorption of solar UV by ozone, and that CO2 has little ability to absorb in the UV. Stratospheric absorptivity is therefore dominated by the UV component. In contrast, at stratospheric temperatures, radiation emitted to space is almost entirely in the IR, where CO2 is a strong emitter. Hence, stratospheric emissivity is dominated by the emissivity in the IR of CO2. As a result, rising CO2 increases the ability of the stratosphere to emit radiation more than its ability to absorb, and the temperature falls. In essence, CO2 serves as an “escape valve” for the heat absorbed by ozone.
Fred,
what you’re saying makes sense to me, but I think we need to parse out exactly what is happening physically.
First, the earth’s surface is emitting a larger flux of IR light than the colder atmosphere. That seems fairly obvious.
Second, we should assume the same amount of visible flux from the sun incident on the surface of the earth, just for ease of understanding.
Now, if we start adding CO2 to the lower layers of the atmosphere, more ‘earthlight’ is getting absorbed and redistributed to the molecules in those layers. That energy then pushes the temperature distribution higher because there is an energy imbalance, more coming in than going out.
Let’s also assume that establishing a new thermal equilibrium happens instantaneously.
The lower portions of the atmosphere are now emitting MORE IR flux, due to higher temperature, than before the addition of CO2. But we know from satellite observations that LESS of this IR flux is in the absorption band of the CO2. So where is the ‘excess’ IR flux being emitted spectrally?
It turns out that the laser community answered this question many moons ago. In determining the dynamics at play in CO2 gas lasers that emit IR light in the vibrational region of CO2 they had to identify all of the decay pathways that did not lead to efficient laser output. Several of these parasitic radiative decay pathways necessitate collisions with N2 or O2. Some of the energy is lost to the colliding molecule and other amounts of energy are lost to IR emission in these decay pathways.
In the lower portions of the atmosphere the density of gases is substantially larger than at higher altitudes. This means that there are more collisions that can lead to the emission of photons that are not in the absorption window of a single CO2 molecule. As the lower densities, it also means there are fewer collisions so that the reverse process, collision assisted absorption, has a very small cross-section.
So it is very likely that some portion of the increased IR flux from the lower parts of the atmosphere is in a spectral region in which CO2 molecules at higher altitudes cannot absorb, meaning most of the IR light in those spectral gets to space without interference from the stratosphere.
At the same time, I think the UV absorption of ozone and redistribution to CO2 via collisions process you outlined is still playing the role of a UV energy dissipation mechanism for the stratosphere.
So I’d say it’s some rather complicated combination of these processes that leads to the cooling of the stratosphere.
In either case, however, the signature of greenhouse warming is not a change in the net energy of the climate system. Simply changes in energy stratification within the climate system, which is the larger, more important point.
Fred,
your labeling of my assessment incorrect necessitates the assumption that all of the increased upward IR flux of a warming lower troposphere is in the same spectral window as CO2 absorption.
Satellite data confirms that the emission to space at 15 um has diminished, meaning that if TOA net flux is to stay at zero (also confirmed by satellites within the detection limit of the instruments), other spectral regions of the IR have to make up the difference.
Luckily for us, there are several collision assisted emission pathways for vibrationally excited CO2 molecules that have been investigated and found via the CO2 laser community in the late 1960’s and early 1970’s. Such laser systems also make use of pressure broadening via N2 and O2.
That is, some of the energy of the CO2 molecule is lost to the colliding molecule while some of it is also emitted as a photon of lower frequency than the originally absorbed photon.
The collision assisted emission regions are also important from the standpoint that the reverse process, collision assisted absorption, is much less likely at higher altitudes due to reduced gas densities.
So while the temperature profile of the lower troposphere changes (increases) in response to increases in CO2 concentration, the emitted IR flux is not the same spectrally, which matters in the context of molecular absorption at higher altitudes. Because the IR flux due to collision assisted emission is largely not absorbed at higher altitudes, CO2 is ‘effectively’ reducing the available IR flux that warms those higher altitudes.
I think your explanation of UV energy dissipation via CO2 is still valid likely plays a substantial role in stratospheric cooling. I just think we cannot discount that the spectral content of the ‘earthlight’ absorbed by the lower troposphere is not the same the spectral content of the IR flux emitted by the lower troposphere due to the difference in the physical processes at play.
All in all, however, the larger and more important take home point is that the net energy of the earth’s climate system does not change in response to an increased greenhouse effect. It is the energy differences between the layers of the atmosphere that changes in response to changes in the greenhouse effect.
Yes, but as long as the troposphere is warmer, it will radiate more IR in wavelengths absorbable by CO2, and so the stratosphere will be exposed to those wavelengths. As Pierrehumbert has pointed out, in the absence of ozone, increased CO2 would cause the stratosphere to warm.
Fred,
‘…but as long as the troposphere is warmer, it will radiate more IR in wavelengths absorbable by CO2…’
Then why are we seeing decreases in the intensity of 15 um coming from the atmosphere in satellite data? There has to be a Stokes shift of that energy somewhere along the line
I mean, I understand that as a blackbody increases in temperature, the total amount of the light across the entire spectrum increases as per the Stefan-Boltzmann law. I’m simply perplexed as to how we should expect MORE 15 um due to this fact, and yet we measure less when we are also measuring the net zero flux of total radiation at the TOA.
That seems contradictory to me on first thought, though it wouldn’t be the first time I am mistaken, nor likely the last.
Less energy is emerging at 15 um because more of it is absorbed in the atmosphere, including an increase in the amount absorbed in the stratosphere. The result of the increased absorption is a warming atmosphere, and a shift in the TOA emission spectrum to regions where IR absorptivity is reduced or almost absent. In essence, the stratosphere is seeing more 15 um IR from below and is emitting less to space, with a consequent shift of emissions to other wavelengths.
Fred,
I believe I know roughly, what is going on in the atmosphere with 15 um radiation, but about your last message: I cannot tell, whether I agree or disagree, because I do not understand, what it is supposed to tell.
Pekka – My previous explanation was somewhat oversimplified, although I tried to describe the basic principles. An elevated CO2 concentration results in more absorption in the main CO2 absorption band centered at 15 um, reducing emission to space, and creating a “trough” in that part of the IR spectrum as seen from space, because the resulting increase in surface temperature leads to more IR escaping at wavelengths of low IR absorptivity. This happens in both the troposphere and stratosphere.
Within the stratosphere is an interesting anomaly at the very center of the band – i.e., at 15 um. IR opacity is so high at this wavelength that emissions can’t escape to space except at altitudes where the temperature is actually higher than below, due to ozone-mediated warming. This results in a “spike” in the center of the trough, due to the fact that warmer temperatures lead to higher emission rates. Here, when CO2 rises, stratospheric absorption rises. What happens to emissions at 15 um depends on the ultimate temperature. Before equilibration at a colder temperature, emissions will increase slightly as well (at 15 um, while declining to the left and right of 15 um). After equilibration, increases in emission will be less than increases in absorption. Of course, in the absence of atmospheric CO2, 15 um absorption would be less and emission seen from space would be higher than at any CO2 concentration.
Some of this is depicted at a site Eli Rabett linked to earlier – TOA IR spectrum
I’m still not satisfied I can predict exactly how the 15 um “spike” region will behave after equilibration at colder stratospheric temperatures and in the presence of ozone. We know that the emission to space will be less in the presence of CO2 than in its absence, but it’s less clear how emission rates will respond to specific changes in CO2 concentrations. Stratospheric cooling obviously requires total emissions to rise more than total absorption, but once the stratosphere has cooled, emission to space at a hypothetical “mean emission altitude” must balance absorbed upwelling IR plus solar UV absorbed by ozone. Although total IR absorbed in the stratosphere will have increased, the absorption rate at the emission altitude may have either risen or declined as a function of the change in height of that altitude, and it may be hard to determine the direction from back of the envelope calculations.
In the absence of ozone, stratospheric IR absorption overall would increase, but emission in the more IR opaque wavelengths would decline because of a rise in the height (and consequent reduction in temperature) of the radiating altitude. Under those circumstances, the stratosphere would warm rather than cool.
My initial point- that stratospheric cooling results from the ability of CO2 to shed atmospheric heat derived from ozone, remains unchanged, and the point is described quantitatively in the Hartmann and Pierrehumbert references I cited earlier.
Fred,
I thought I was starting to get a little bit but you threw me. If I understood Pekka correctly, CO2 primarily emits as a result of collisions with other particles in the troposphere. As the atmosphere warms these collisions should happen more often emitting more IR.
You are telling me that as the atmosphere warms for some reason this is not happening. That apparently the emissions are moving to different wavelengths? Help?
My comment a few messages higher up on this same level was actually trying to point out that the descriptions given are too difficult to understand (and I would not put it on my knowledge of English) and likely to allow several different interpretations.
There are many factors influencing: strengths of emission at different levels below, absorption in intervening levels, line widths at various altitudes, heating by UV, rates of thermalization at different levels in stratosphere and certainly still something more. With all these factors influencing the outcome, trying to explain it with a set of short messages does not work. It would be necessary to work for a while to build a full logical description of the whole, telling why certain factors dominate and other are weaker, while still present. Only in this way can a convincing presentation be obtained.
The situation is made more difficult by the fact that the scientific knowledge on some of the issues needed in that description are still open, if I am not mistaken. In some details it appears not to be fully known, what the relative strengths of the various factors are and this has led to some surprises when new empirical results have come.
None of these open issues is important concerning the warming of troposphere or Earth surface, but the details are scientifically interesting on their own right.
Fred,
thanks for the detailed messages. I am not satisfied with my own understanding of the balance between all the processes at hand either.
One thing bugs me the most, however. If CO2 acts as a sink for UV energy in the stratosphere, wouldn’t increasing CO2 concentrations in the stratosphere cause satellites to measure MORE 15 um light coming from earth with all else held constant (yes I know that’s not the most ‘physical’ model)?
I mean, on a photon per photon basis, there is much more energy that can thermalize in a UV photon versus a 15 um photon. Two orders of magnitude more energy in fact.
So if that energy is redistributed to more CO2 molecules, why would we expect less 15 um light being emitted to space?
I’m wondering if this description necessitates the use of the complete bath of the degrees of the freedom for energy transfer at each layer.
Does anyone know if such an analysis has been undertaken?
Thanks to all for the stimulating conversation in either case.
Maxwell,
One observation is that the amount of energy absorbed in UV is independent of the components, which do not have significant absorption in UV. All the energy absorbed and transfered through thermalization to the kinetic energy, must ultimately be emitted by some GHG as IR, when other mechanisms of energy loss are very weak. Finally we may conclude that the only thing that changes with the CO2 concentration with respect to emission concerns its ratio to emission by other GHG’s present in that particular layer of stratosphere.
At the same time the CO2 acts as absorber at those wavelengths where the narrow absorption peaks that correspond to the low local pressure and temperature are strong. The absorbed energy is partly re-emitted without thermalization and partly adds to the local temperature.
The balance of all these effects is complicated enough to make quick back-of-envelope estimates doubtful and thus requires a better quantitative analysis before any conclusions can be presented. That is at least, what my intuition tells.
Hi Maxwell – (kuhnkat see the end part of this comment) –
Maxwell -I think there are two issues here. The first is why the stratosphere cools, and that is reasonably well understood to be due to the ability of CO2 to increase stratospheric emissions in the IR, without a commensurate increase in stratospheric absorption of radiation, because the latter is mainly mediated by ozone in the UV. It is not due to reduced IR upwelling into the stratosphere, because that IR upward flux is actually increased due to the warmer troposphere.
The second issue is the profile of IR emissions, with special attention precisely at the CO2 maximum (about 15 um). I believe it is possible to talk about the extremes, but what happens in intermediate CO2 ranges is less clear. Let’s start with no CO2. The TOA emission profile will show high 15 um emission, because it is all coming from the surface at surface temperature. As CO2 is added, more IR will be absorbed, the “trough” will begin to appear, and radiative balance will come about through shifting of some IR radiation to low absorptivity wavelengths distant from 15 um (this is the “spectral shift” attributable to surface warming with consequent increase in emissions at wavelengths that are not very opaque). With still further CO2, absorption is sufficient at 15 um to move most of the 15 um emissions escaping to space into the stratosphere, where temperature increases with height. As a result, the “spike” appear at 15 um, indicating that emissions are beginning now to come from a warmer temperature than the temperature below. It will still be true, however, that overall emissions will have been spectrally shifted to low absorptivity regions at the expense of wavelengths at or near the 15 um line. The height of the spike will be lower than would have been the smooth Planck-type curve in the absence of CO2. The spike reflects the fact that emissions are emanating from a region warmed by ozone (from UV absorption), but at the same time, the stratosphere cools (see my first paragraph), and so the rate of 15 um emission will reflect: (a) the increase in temperature with height; (b) the overall reduction in stratospheric temperature; and (c) the increasing “spectral shift” with increasing CO2.
Note that the relative strength of UV and IR photons is irrelevant. IR emissions will be a function of temperature. Ozone absorption of solar UV increases temperature, but this is highly dependent on ozone concentration. With almost no ozone, there would be little temperature change regardless of UV photon strength.
At relatively modest CO2 concentrations, it is probable that the cooling and spectral shifting will dominate, and 15 um emissions will not increase with increasing CO2 – i.e., even the spike region will remain much lower than the Planck-type curve level without a trough carved out of it. At much higher CO2, I’m not sure what happens, even with this simplified mechanism ignoring water, convection, changes in troposphere height, dependence on ozone concentration, and other variables that would be important in real world computation. It is possible that the spike height would increase, but very unlikely that even that point, which is higher than elsewhere in the trough, it would reach the emission rate that would prevail without CO2.
This may still sound confusing, but it’s the best I can do. Visiting the diagrams in the link to Eli Rabett’s page will be helpful in sorting some of it out (see above comments).
Kuhncat (very briefly) – Increasing CO2 absorbs more IR so that in the more opaque wavelengths, IR can’t escape until altitudes are reached with too few absorbing molecules to interfere. These are colder (but see my comments above re the 15 um spike). For sufficient emission, the temperature must warm, which is achieved via radiation downward through the atmosphere and to the surface. When the surface warms, it emits more IR in all wavelengths. These include wavelengths where there is little absorption by GHGs. This permits the total IR escaping to space to balance the incoming energy through a shift away from the highly opaque wavelengths to those outside the CO2 band, or at its margins. Consequently total emissions to space in the more opaque regions decline.
Fred,
“The actual explanation resides in the fact that much stratospheric warming is due to absorption of solar UV by ozone, and that CO2 has little ability to absorb in the UV. Stratospheric absorptivity is therefore dominated by the UV component.”
I am trying to get a magitude sense of O3 absorption of UV energy compared with other wavelengths, assuming that the incoming sunlight has an influx of 390 W/m2 before entering the atmosphere.
1. How much UV energy in the sunlight entering the Earth’s atmosphere is absorbed by the O3 in the Stratosphere?
2. How much UV energy in the sunlight as compared with the spectrum of sunlight?
3. How much IR energy in the sunlight as compared with the complete spectrum of sunlight?
4. How much IR’s 15 um energy in the sunlight as compared with the whole spectrum of the sunlight?
That magnitude of energy temporary retained thru CO2 is ->0 and very short retained duration when compared with the magnitude of other masses present on the Earth’s gases, liquids and solids. Plant and animal growths retain energy longer and release the energy thru decays or preserved to become fossil fuels.
Eli will put it down here because we have run out of repies, but this is really a reply to one of Fred’s questions. Stratospheric cooling due to CO2 increases, are a combination of LESS emission from the troposphere because the light is trapped by the higher CO2 concentrations down there (before anyone gets crazy, google radiation trapping) and MORE emission from the stratosphere where there is more CO2.
Eli – That is incorrect. When the troposphere warms due to a rise in CO2, it emits more rather than less radiation upwards in CO2-absorbable wavelengths – how could it not? In fact, as Raypierre has pointed out, a stratosphere without ozone would warm rather than cool as CO2 increases (although it wouldn’t really be a stratosphere, but more like an extended troposphere). The mechanism for stratospheric cooling is the disproportionate increase in emissivity over absorptivity, because the former is dominated by IR emissions while the latter reflects substantial UV absorption, which changes very little with added CO2. The mechanism is well described quantitatively by Dennis Hartmann in his Global Physical Climatology text and by Raypierre in Chapter 4 of his new book.
Hmmmm,
very very interesting and one of the most telling exchanges on the whole thread…
Here we have one of the chief defenders of the “greenhouse” theory, Joshua Halpern (pseudonym Eli Rabett), a professor of CHEMISTRY at Howard University who arrogantly calls those who question his “greenhouse” theory “crackpots,” indeed has his own crackpot theory that CO2 knows whether to “trap radiation” or not depending upon concentration.
Eli: nothing in the universe can “trap radiation” other than a black hole. Sorry, that includes CO2.
BTW folks: this is the first author of the supposed “rebuttal” to the Gerlich and Tscheuschner paper falsifying the GHE.
Obviously, even the warmists cannot agree upon the most fundamental basics of their “greenhouse” theory. Upon this unbelievably shaky foundation we are led to believe $45 trillion must be spent, “the debate is over,” damn the poor, and full speed ahead!
I have enormous respect for Josh’s understanding of the basic principles underlying the ability of greenhouse gases to absorb infrared radiation from below and through a process that involves re-emitting it isotropically, warm the atmosphere and the Earth’s surface. In this instance, I have given reasons to disagree with him – not because he is wrong about what CO2 does regarding absorption (which he calls “trapping” without implying that the absorption is permanent) but because he neglected the emission increase that accompnies the process. If I’m right, it’s an error regarding how the stratosphere behaves. In my view, his understanding of how CO2 and other greenhouse gases warm everything below the stratosphere, as well as the substantial magnitude of the effect, is completely accurate.
Fred,
This goes to my continuing confusion. It has also helped me to remember the explanation I read. The speed of emission in the upper trop is supposed to lag the increasing IR so that it is basically overwhelmed and warms more. This was an issue with the average emissions altitude. The tropopause rises with the heating of the atmosphere putting the upper trop at a higher, cooler level reducing its ability to emit.
This, of course, would start out for a tiny amount of time during the day and increase over time. That was the “official” explanation of the Greenhouse. The stratosphere really didn’t affect the warming in that scenario.
Of course, if the CO2 is cooler it DOESN’T emit as much so the Bunnie said what he meant and meant what he said. The question is, does the warming troposphere that moves the tropopause up not also warm the upper trop? Why wouldn’t it. If it does then there should be no issue with the speed of emission. If it doesn’t warm the upper trop so that the CO2 doesn’t retains its emission speed, why not?
Can you shed any more light on this issue??
Fred,
“… In my view, his understanding of how CO2 and other greenhouse gases warm everything below the stratosphere, as well as the substantial magnitude of the effect, is completely accurate.”
What is the “magnitude” of energy at 15um IR wavelength in the complete IR radiation spectrum of 0.039%?
Fred,
You seem to be arguing that there must be more emission upwards from the troposphere with increasing CO2, because troposphere is warming. The warming is, however, obvious at fixed altitude, only, but the level, from where the radiation occurs is rising, which has an opposite effect. The radiative balance may be reached by more radiation at other wavelengths.
Whether the upward radiation from troposphere is increasing at 15 um or not, cannot be decided stating “how could it not”. It is a quantitative issue that requires empirical data or reliable detailed calculations to be determined.
Fred,
“… the ability of greenhouse gases to absorb infrared radiation from below and through a process that involves re-emitting it isotropically, warm the atmosphere and the Earth’s surface.”
What is the mass of 0.039% of CO2? How much IR energy can 0.039% of CO2 can absorb at 15 um wavelength? What is the specific heat capacity of CO2? If we assume the solid mass of the Earth surfaces do not exist, just 10m deep of ocean water exist, discounting the reflections, how much energy the water absorb from the whole light spectrum from uv to IR and how much IR energy from the 0.039% CO2 15 um wavelength in the atmosphere? I assume we are all well versed with latent heats of water and specific heat of water, basic physical properties of water including water vapor.
Irrelevant question.
All of it and many times on the way up through the atmosphere as it also emitted many times.
Irrelevant, because heat is shared efficiently by all gas in the atmosphere.
Oceans absorb more than 90% of solar radiation that reaches it, but not all in the top 10 meters as light penetrates to a significant extent deeper. Oceans absorb very close to all IR that reaches its surface and this happens in a very thin skin layer (the same layer that also emits IR and more of it than it receives).
Fred,
“In my view, his understanding of how CO2 and other greenhouse gases warm everything below the stratosphere, as well as the substantial magnitude of the effect, is completely accurate.”
You did not answer any of my questions above. Will you be able to substantiate “the substantial magnitude” of the effect in the above?
Fred, take a look at this (also linked toat RR which has some more info)
To quote:
————————————-
The second effect is more complicated. Greenhouse gases (CO2, O3, CFC) absorb infra-red radiation from the surface of the Earth and trap the heat in the troposphere. If this absorption is really strong, the greenhouse gas blocks most of the outgoing infra-red radiation close to the Earth’s surface. This means that only a small amount of outgoing infra-red radiation reaches carbon dioxide in the upper troposphere and the lower stratosphere. On the other hand, carbon dioxide emits heat radiation, which is lost from the stratosphere into space. In the stratosphere, this emission of heat becomes larger than the energy received from below by absorption and, as a result, there is a net energy loss from the stratosphere and a resulting cooling.
—————————-
Figure 3 tells the tale
This entire farago makes it clear that Eli has to do a post on radiation trapping.
Bunnie,
OOOPS, I was wrong about what you were saying!!
Can’t wait to hear from the experts!!
OK Bunnie, I can’t resist the bait.
If the IR is TRAPPED in the lower atmosphere where does the backradiation come from?? It is actually omnidirectional so if it isn’t going up it isn’t going down either.
From within about 10-100 m of the ground.
Radiation in the region of H2O and CO2 spectral lines can only go about that distance without being absorbed (as a rule of thumb, about 70% is absorbed in about 10 m).
OTOH, radiation from the surface in the right spectral region only gets 10-100 m before being absorbed.
Radiation from higher up will not reach the surface (you can caveat this a bit, but they are just caveats). Radiation from higher up can be absorbed a bit further down (10-100 m) and then the molecules lower down can radiate, etc.
Essentially it looks more like a random walk or a diffusion process then the kind of model people are using.
If the distances would be so short (< 100m) for all wavelengths, the radiative heat transfer could be analyzed as a form of conduction. This is, however, not a good description at wavelengths with a mean free path of kilometer or more as the temperature difference between the point of emission and the point of absorption starts to be too large for this approach. The small number of steps needed to escape to the space leads also to deviation from the diffusion equation.
Eli – This is a response to both you and Pekka (see above). The sites you link to are victims of the same very common misconception I addressed above – namely, that with increased CO2, less IR is emitted from the troposphere into the stratosphere, and the reduction contributes to cooling. This cannot be a cause of cooling, because increased CO2 results in more rather than less IR upward flux.
The troposphere (by definition) is characterized by a positive lapse rate – temperature declines with altitude. At any altitude, a rising CO2 level will result in warming, because it moves the mean escape level higher. As a consequence, all tropospheric altitudes will radiate more IR in CO2-absorbable wavelengths than those same altitudes did at a lower CO2 concentration, including more in an upward direction into the stratosphere, and hence the stratosphere will receive more IR from below. With increased CO2, tropopause height rises, but this cannot cause any altitude within the troposphere, even the highest, to become cooler than it was earlier. It will in fact become more optically thick, absorb more, and emit more as a consequence of its higher temperature. In fact, the warming is how the tropospheric radiative profile adjusts be permit IR to escape to space in response to the increase in optical thickness. There is no physical mechanism whereby a warmer layer will emit less, nor is there a physical mechanism whereby a positive lapse rate can be associated with cooling as optical thickness rises.
If anyone is unsure of this, he or she should try a reductio ad absurdum argument – select any altitude of one’s choice within the troposphere after an increase in atmospheric CO2, and then try to define a way for that layer to emit less IR upward. One can even imagine a layer at about the tropopause that was technically within the stratosphere before the rise (it was cooler than higher temperatures), but which becomes part of the troposphere after the rise (because it has warmed). The result will always be the same – higher tropospheric temperatures and higher upward fluxes at every altitude.
In the absence of ozone, there would be no tropopause and no stratosphere, because the lapse rate would continue positive. All layers would warm at an asymptotically declining rate. The stratosphere represents a layer where the lapse rate has shifted from positive to negative due to ozone-induced warming at higher levels. The same shift to higher altitudes that causes all tropospheric altitudes to warm will, in the stratosphere, cause higher altitudes to cool, because as a mean escape altitude rises to higher levels that are warmer than lower levels, the increase in emission rates will enhance rather than impede IR escape to space.
Note that in all the above, I’m neglecting changes in convection and water vapor, but these should magnify rather than reduce the enhanced IR flux into the stratosphere with increasing CO2.
Eli – This is one of those circumstances where casual intuition leads to a false conclusion (e.g., more “trapping” causing less flux). You should correct any misimpressions on your blog that imply that less IR reaches the stratosphere as CO2 rises. The fact that the misconception is widespread makes it all the more important to correct it rather than perpetuate it. Once readers are reminded of the specific relationships that exist between altitude, temperature, and isotropic flux rates, the correct picture, which is not really in doubt, will become clear.
Fred,
I think that I am on board with the idea that it is hard to get an accurate picture of what is happening in terms of specific flux (upward or downward) at a specific height in the atmosphere without doing a detailed calculation. The fact that even experts are presenting different interpretations of the same phenomena is driving this point home for me.
One point of serious confusion on my part, however, concerns your explanation of increased flux in CO2 absorbing bands from lower atmospheric layers, but shifts away from such bands at higher altitudes. It seems you’re saying that at different altitudes we would expect different physics from atmospheric gases completely dependent on differences in air pressure.
If the spectrum emitted by the upper reaches of the stratosphere (pretty warm by most standards) shifts in response to CO2, why won’t the spectrum of lower layers at the same temperature also shift similarly?
I mean, we’re not really talking about ‘blackbodies’ here, right?
Fred,
From the point of view that I was presenting, the essential question is: How precisely are the altitude and temperature of the tropopause determined, i.e. how far up extends the adiabatic lapse rate and what happens at altitudes close to this level. As I have not gone through any advanced material, I have not seen this issue described. How increased CO2 affects tropopause, it would be necessary to have a fairly detailed description of the energy balance of troposphere taking into account the increases in the radiation escaping the atmosphere at wavelengths of little absorption and several other issues.
I have not really taken position on the issue, but only noted that additional arguments are needed in addition to what is commonly seen. It may be that a warming (at fixed altitude) extending to the lower edge of stratosphere can be argued with little addition, but even your latest message leaves some details as declarations, whose basis is not really given.
I am adding Pierrehumbert’s book to my collection, but have not yet received it.
For Pekka, Maxwell et al –
Regarding flux into the stratosphere, I agree that quantitation is difficult, but I believe the direction is clear – as CO2 rises, more IR will enter (and leave) the stratosphere in CO2-absorbable
wavelengths.
To see why this must be true, consider another thought experiment in which we evaluate the alternative explanation – that with rising CO2, one part of the atmosphere grows warmer, while a different, higher part becomes cooler due to less IR flowing from the warmer to the cooler part. For this to be true, there must be a “transition layer” (TL). Immediately below it, by definition, the atmosphere has warmed from its previous temperature. Immediately above it, the atmosphere has cooled.
We must now explain why the warmer layer immediately below the TL will emit less IR upward into the layer above the TL than it did before its temperature rose. Given that IR flux is temperature dependent, I can conceive of no mechanism that would permit this, but I would be interested in any explanation to the contrary.
On the other hand, cooling is easily explained if the stratosphere acquires an enhanced capacity to shed heat despite the fact that it is receiving more from below. That appears to be the correct explanation.
Regarding wavelength distribution, including the 15 um line, more 15 um IR will enter the stratosphere from below (simply because the troposphere is warmer). How much leaves the stratosphere at 15 um as opposed to other wavelengths is unclear to me, and I have speculated that there may be a shift toward wavelengths somewhat distant from 15 um – although I’m not sure about this. The reason is that the different wavelengths can escape to space at different mean altitudes, with 15 um escaping at the highest altitude because the stratosphere is optically thickest at that wavelength. This is also the altitude that cools most, however, with increasing CO2, while those nearer the edges of the CO2 band will escape at lower altitudes that cool less, and in the vicinity of the tropopause may even warm. I don’t know, however, whether this quantitation is possible without some more complex modeling than can be done on the basis of these back-of-the-envelope estimates.
Fred,
The possibility which I see difficult to exclude so easily comes from the combined influence of radiative processes and convection. The idea is that tropopause would move so much higher that the increased range of validity of the adiabatic lapse rate would reduce the temperature at tropopause more than the warming at fixed altitude in troposphere raises it. At the new tropopause and just below it the temperature would be lower than it was at any altitude before the change.
As long as we are within the troposphere convection determines the lapse rate. Thus it is not so easy to argue that reduced convection could not counteract the increase in radiation. Whether the combined effect of changes in both convection and radiation could raise the altitude of tropopause so much that its temperature decreases, seems to me a bit more difficult to decide. It is quite possible that you are right, but the arguments are not yet quite convincing.
Pekka – The effect of warming due to CO2 increases is to trigger an increase in convection. These convective adjustments raise rather than lower the temperature at higher altitudes – i.e., they reduce lapse rates. I don’t believe therefore that they could cause a high tropospheric altitude to become cooler and emit less IR.
Fred,
Yes I know, but the effect was there within the troposphere also before the increase in concentration. The sign of the difference must be checked looking at the total balance and all changes to it.
I’m not sure what you mean with your latest comment. However, go back to my thought experiment a couple of comments above. If the lower part of the atmosphere warms with more CO2, and a higher part cools, there must be a specific transition layer – the air below it is warmer than before and the air above it is cooler than before. To postulate reduced upward flux, one must explain how the air that is warmer can emit less IR upward than before. I don’t think that’s possible.
Fred,
Your latest argument assumes that there cannot be other factors that explain why temperature drops below the earlier temperature of the tropopause in addition of the increased emissions by CO2, that you accept as the correct reason. If such factors influence the new tropopause, then we have lower temperatures and perhaps less radiation because of that in spite of increased CO2.
This could of course not be explained by reduced radiation from below, but this could be used as a partial explanation for even higher altitudes.
This is essentially the situation that I had in mind.
If we agree, as I think we do, that the stratosphere cools because higher CO2 levels enhance the escape of ozone-generated heat, then some of that cooling could reach the tropopause. Conversely, CO2 increases in the troposphere would tend to counteract that effect. I’m not sure of the net effect. In any case, the cooling mechanism starts with absorption of solar UV by ozone, and the dissipation of this heat by increased CO2. I’m not aware of any mechanism for stratospheric cooling that would operate in the absence of ozone.
None of this, however, is germane to the original point, and to the incorrect argument made by Josh Halpern, which was that reduced upward flux to the stratosphere was the result of more IR absorption at lower levels, causing a “trapping effect”. There is no tenable physical explanation for that possibility – it’s simply wrong.
Fred,
I do agree that the point is not of great significance. I agree also, that it is unlikely that less radiation from below would be a significant basic factor.
Still I lack the knowledge on how changes in the CO2 concentration of the troposphere end up influencing the altitude of the tropopause. To me the situation appears complicated enough to make me careful on the logic “it must be so, because I cannot explain it in other ways”.
Here we are discussing the real atmosphere, not a simplified model. Thus we should know, how changes in the clouds influence the situation, how changes in water vapor influences it etc. Much of the change in the flux of outgoing radiation is related to radiation leaving from surface, clouds and atmospheric water at lower levels.
Increased temperatures at the lower levels increase radiation compensating the effects of added absorption. Therefore no simple argument tells directly which way the the temperature of tropopause finally changes, when the change of altitude is taken into account. I wouldn’t dare to draw a conclusion without a full quantitative analysis and empirical confirmation of its validity as some influential factor may otherwise be left out.
Or at least I would require stronger arguments than what I have seen to change my mind.
Pekka – My point is fairly straightforward. Increasing CO2 can cause the stratosphere to cool only because the presence of ozone-mediated warming increases its ability to emit IR. CO2 can’t cause the stratosphere to cool by a mechanism independent of ozone whereby more IR absorbed in the troposphere causes less to flow into the stratosphere.
I don’t think the point is completely insignificant, because stratospheric cooling is an important element of climate change and is often incorrectly attributed to IR “trapping” below the stratosphere due to the increased CO2 concentration in the stratosphere. That is the opposite of what actually happens. Increased absorption in the troposphere must inevitably lead to more rather than less upward flux into the stratosphere, and I believe the various web sources that state differently should be corrected.
As I suggested above, in the presence of the ozone mechanism, the tropopause temperature might be cooler than it would be without the ozone, but that doesn’t validate the incorrect explanation of “trapped” radiation (i.e., more absorbed being equated with less emitted)- it’s still wrong.
My above comment should have read “due to the increased CO2 concentration in the troposphere”.
Fred,
The trivial part is that the total IR reaching stratosphere from below must increase, less trivial is the spectrum of this radiation and thus the share that will be absorbed by stratosphere.
One factor that has effects in both directions is the pressure dependence of the line shape. On the edges of the lines the average altitude of emission is lower and the temperature of the emitting gas higher. This part of radiation from CO2 is not absorbed effectively by the stratospheric CO2. On the other hand the radiation from the top of troposphere is coming from higher altitudes than with less CO2 and has a narrower line shape. Therefore it is absorbed more efficiently in stratosphere. One factor adds radiation that is not absorbed, other has the opposite effect, which wins is not immediately clear.
The line shape is one part of the spectrum, the other part is the total share of CO2.
CO2 is colorless, how light is trapped by higher CO2 concentration? The best CO2 can absorb (not trap) is 15 um of the whole uv to IR light (or E-M) spectrum. I thought its very easy to demonstrate to fill a glass tube with 100% CO2 and then shine light on it to see if all light pass thru it. Physics or unphysics, very confusing!
Hi
As was revealed on The Simpsons – Chief Hydrologist is a sacred vocation and not my name. Please call me Rob.
If you have a look at the ERBS and ISCCP-FD data for SW and LW flux at top of atmosphere – and the 2 International Satellite Cloud Climatology Project graphs are on the site I linked to – does as I say show a substantial increase in IR emission at top of atmosphere (TOA) between 1984 and the late 1990’s. So as far as the data is concerned, you might be right.
Let’s forget about processes in the atmosphere or oceans for a moment and look at the planet from the God perspective – high up above the atmosphere. Energy comes in from the Sun, is reflected from cloud and is emitted as an infrared flux.
At toa – there are only 2 things – SW and LW radiative flux both from the planet and the sun. (Neglecting UV for the moment – UV might in fact be surprisingly important in climate) These change all the time – mostly as a result of cloud changes in recent times.
The planet has a certain heat content – did I say mostly in the oceans? Heat content changes all the time as well.
Energy is conserved – I hope you agree. So any difference between incoming and outgoing energy must result in a change in the heat content of the planet. This is almost trivial – but understanding comes from formalisation.
The simple differential energy equation is very obvious and robust – it is concerned only with radiative flux outside of the atmosphere and whether the planet is warming or cooling. It is just a tool for understanding data on radiative flux in particular. And the data shows some very interesting things such as a very substantial decline in cloud cover – 10 times the worst case radiative effect of AGW – between 1984 and the late 1990’s.
If you understand this – and look at the Pacific for why – then rejecting the AGW meme is no longer on theoretical grounds but is based on physical evidence.
C H
We have a plethora of Robs (and Barts) — for which one believes we can thank the Normans in 1066 and the Indo-Europeans about 4000 BCE — and so few sacred vocations or references to pop culture.
For clarity, perhaps best if we stick to your title.
Well – I don’t mind of course. It is an honor to serve.
I am most impressed with your erudition and urbane charm and thank you for your comment.
Will, you have missed the main point. Increasing CO2 means that the emission in the CO2 bands will come from from HIGHER in the atmosphere, where it is colder, and therefore the rate of emission is slower. This slowing of the rate of emission in the CO2 bands requires that the rest of the earth system warm in order to force more radiative energy through the spectroscopically open windows. The downwelling radiation is part of the story about how it warms.
More to the point greenhouse gases absorb IR light from the surface. For CO2 and H2O and to a lesser extent methane, the average distance a photon travels is a few tens of meters near the surface. That energy gets degraded to heat by collisions. Further collisions then excite other CO2 molecules, some of which emit, in any direction, etc. As you go up in the atmosphere, the density decreases and the temperature cools. The net effect is that radiation in the region of the CO2 bands cannot be lost to space from low down in the atmosphere where it is warm, but only from high up (about 8 km) where it is cold(er). In those regions the emission rate is slower. (Here is an interesting puzzler that shows you what is happening and here is the answer).
Well, Mr. lagomorph (bunny), I think you have dug a big hole and are still digging:
You say:
“Will, you have missed the main point. Increasing CO2 means that the emission in the CO2 bands will come from from HIGHER in the atmosphere, where it is colder, and therefore the rate of emission is slower. This slowing of the rate of emission in the CO2 bands requires that the rest of the earth system warm in order to force more radiative energy through the spectroscopically open windows. The downwelling radiation is part of the story about how it warms.”
Well, in my opinion, while Will does not understand much of physics, he is bringing out some really crazy voices on the other side that need to be heard by the lurkers.
While you have a wonderful hypothesis, supported by hundreds of “scientists,” the problem is that you have absolutely no empirical evidence to support it, and you are completely ignoring all the possible feedbacks that might negate/modify your simplistic idea!
Interestingly, Gaia is not cooperating with you warmistas lately, and you seem to be trying to hide that fact. The temperature has not gone up for 15 years, and it is now currently below the 30-year average. There is no “hot spot” at mid-lattiude–mid altitude, as predicted by the models your religion relies on.
Climategate happened and people noticed that it was brushed under the rug, so to speak. Big PR problem, bro. Remember Watergate? So now can you be surprised that the public laughs when someone mentions Al Gore, “global warming,” or even “climate change.” In short, you scam artists are in trouble and you know it, as attested by the latest Lisbon conference (another story on just how seriously you guys are in trouble).
The best course of action for climate scientists right now is to just shut up.
OK
twice
thrice
Which of these negative feedbacks explains what’s happening in the world?
Cloud feedback from Pacific Ocean SST – in the warm El Nino dominated Pacific mode from 1977 to 1998. What – you haven’t heard of the Pacific climate shift of 1976/77? More low level marine cloud forms over cool water than warm so cloud is negatively correlated with SST
It explains the massive decrease in reflected SW in the ISCCP and ERBS record between 1984 and the late 1990’s.
there is a review here – http://www.earthandocean.robertellison.com.au/
JAE,
I understan the so called “physics” very well son, I just happen to know it’s bollocks!
Josh Halpern,
Your sophistry is wearing very thin. I will break some of it down and show exactly where your circular logic fails.
You base your fallacious argument on the initial fallacy thus:
“Increasing CO2 means that the emission in the CO2 bands will come from from HIGHER in the atmosphere, where it is colder, and therefore the rate of emission is slower.”
The first fallacy is therefore that increasing CO2 will increase the average emission high of the atmosphere, which itself is a circular argument. The only way to increase the overall emission hight of the atmosphere is to increase its mass/energy and CO2 can do neither without circular arguments such as above.
Then you continue:
“This slowing of the rate of emission in the CO2 bands requires that the rest of the earth system warm in order to force more radiative energy through the spectroscopically open windows. The downwelling radiation is part of the story about how it warms.”
Firstly, by your own pseudo science hypothesis, increasing CO2 actually increases the rate of emission. You lot really need to make up your minds because you simply cannot have it both ways.
As for the rest of this of this statement we are back to the circular logic because you have no anomalous warming to show and you cannot demonstrate that CO2 causes warming. Round and round in circles.
The second paragraph is pure pseudo science built on the fallacies in the first paragraph and I’m not going to waste my time on it. But I will draw attention to one point.
The 8 km point.
The atmosphere begins to emit at about cloud level, but even this is dependant entirely on the difference in temperature between the ground and the air above, i.e. if the ground is cold and the air above is warmer and ladened with water vapour the air will cool/emit, producing mist or fog.
But generally cloud level which begins at around 5 km is usually, under average conditions, the altitude at which the a atmosphere begins to emit IR. TOA on the other hand is considered to be around 30 km, although this could also be argued as unrealistic.
Therefore there is at least 25 km of atmosphere emitting in three dimensions at the speed of light. According to your own pseudo science, increasing the ratio of CO2 in the atmosphere will increase the rate of emission above cloud level, which in turn will increase the the amount of energy leaving the atmosphere. But you repeatedly insist the opposite would be the case.
Here I have merely scratched at the surface of your fallacious drivel and circular logic. None of which, under the bright lights of scrutiny, holds any water.
As JAE said when your in a hole, stop digging, even if it is your natural instinct to do otherwise.
Eli Rabbit: “More to the point greenhouse gases absorb IR light from the surface.”
No, Eli, that’s a mischaracterization of the process being only part of the story: so-called GH gases must also absorb IR as they enter the TOA thus filtering energy and preventing it from reaching the surface. Why do you doomsayers always want to infer that the process occurs only one way?
Energy transport via CO2 ( and the broader atmosphere) must be filtering ( collisions, excitation, etc) on the downward, just as much as the upward journey otherwise you face this apocalyptic equation: IN = OUT or BOOM!
To better model the atmosphere as a 3D dynamic system ‘climatologists’ must apply Poynting vectors and thereby concede that, as per the rules of vector calculus, when energy flows in parallel but opposite directions, the sum must be ZERO!
Hey bunnie,
that is exactly the issue I have always had a problem understanding, how more CO2 becomes a choke point.
Lemme see, as we get more CO2 it causes some warming and convection moves it up. More CO2, more warming, more convection increasing the temps at altitude also. As we have more CO2 the concentration also increases through cross section. More CO2 at the upper trop, more radiation. Of course, all this warming will increase the pressure raising the height of the tropopause. Now you claim that the average emissions height will increase due to the amount of CO2, yet, the temperature profile should also change with the rise in the tropopause. Does the average emissions altitude change faster than the temp profile?
Does the temperature profile remain the same?
Even if it does, as the tropopause raises the average emissions altitude increases in AREA and VOLUME so even if the temps do not increase fast enough you are increasing the amount of CO2 that can emit to space.
So, how do we know that all of these factors actually add up to a bottleneck and not business as usal or a negative feedback?
Will,
Since the atmosphere is in local thermodynamic equilibrium (LTE), the emission of the IR-active molecules depends on the number of vibrationally-excited molecules. This number is temperature dependent under LTE conditions.
A higher number of CO2 molecules means that the emission height increases looking from the surface or escape depth is smaller looking from outside. This means that on average, IR emission from the atmosphere escapes only from a cooler layer. The source function or the intensity of this emission is a function of the number of excited molecules. This number actually decreases exponentially with the temperature decrease in the atmosphere, approximately according to the Boltzmann-factor according to local temperature. Therefore the temperature dependence overcomes the dependence on the total number of IR-active molecules. The number of vibrationally-excited IR-active molecules decreases with height.
This in turn reduces the outgoing longwave radiation from the IR-active molecules. Which in turn increases the energy content of the earth system, assuming the energy input by the sun is constant.
Increasing energy content leads to an increase in temperature of the surface and the atmosphere.
Note that the emission height or escape depth is different for each wavelength, which complicates matters.
Regards
Günter
And your point?
Will,
The short explanation is that more CO2 means it is emitting at colder temperatures (see Guenter for why), which means less outgoing IR, which means net warming since incoming solar remains constant, and the budget is between net solar and outgoing IR.
The next step is that the atmosphere warms until the outgoing IR is again balanced with net solar.
Jim,
show the net warming anomaly which corresponds directly with CO2 or stop talking crap!
Did you want the explanation of why it should warm, or did you want observations? The question was about the explanation. I answered. Stop moving the goalposts. It is not possible to debate sensibly when that keeps happening. Did you understand the explanation first? Then we can talk about observations.
Statistically speaking, “the tail wags the dog”, is a valid statement.
Do you want the explanation of why that is the case or do you want to talk about why in reality that statement is bollocks?
So you think because warming isn’t statistically strong enough for you yet, it will never happen in the future? Do you see the logical error in that thinking?
You want to talk about the hot spot not being as strong as perhaps predicted. Maybe the tropical oceans have not warmed as much as expected, but only because the Arctic has warmed more than expected which compensates globally, and still means warming is here and observable, but distributed differently, in my opinion. It actually makes sense that the Arctic adjusts more quickly because the CO2 has a more direct effect at the surface there than in the tropics, and sea-ice makes the sensitivity greater too.
When deciding whether or not to condemn millions of fellow humans to being priced out of existence and into extinction, I think I need a little more than a hypothesis that is as flimsy and more riddle with holes than a tramps underpants.
Sorry!
You have a hypothesis that not much warming will happen. Unfortunately science, and even common sense, do not support that hypothesis. Your thread of hope is now down to the PDO as far as I can tell, and that is just a hypothesis too, based on only one cycle of its existence, but sure, stick with it, and see how that goes for you.
Don’t keep on Jim, eh!
Guenter,
similar to my question to bunnie, I think I understand at least part of what you are saying. The point that is sticking with me is what happens to the IR emitted from CO2 just below the emissions altitude. This IR should be more than before because it is warmer. If this IR isn’t going to TOA what happens to it?? Being absorbed by the CO2 in the average emissions altitude, doesn’t it become available to transfer through collision warming the area? As the area warms doesn’t the average emissions altitude emit more?
What keeps the CO2 in the average emissions altitude cooler so that it can’t emit enough if it is receiving more IR than before? I get that it emits less often because it is cooler at higher altitude. Why doesn’t it warm up from the increased emissions from below??? This is especially a wonderment to me as the IPCC says the Tropopause should rise which means to me that there will be more area for emissions under the Tropopause.
Apparently I am missing or misunderstanding something fundamental.
Not sure if this answers it, but let’s say that CO2 doubling reduced the average emission altitude temperature from 255 to 254 K. Then the atmospheric profile warms (ignoring the stratosphere) until the new higher emission altitudes again produce 255 K at which point it is back in equilibrium.
Jim D,
Discussing only the average emission altitude may be misleading. Actually it is not the average but some kind of effective temperature, where all temperature from the surface to TOA are weighted based on the importance of the wavelengths for which they are visible from the space to the total emission.
In some more detail:
With increasing CO2 less radiation from the surface and low clouds gets through the atmosphere while more of this radiation is absorbed higher up heating the atmosphere at those altitudes. Convection influences the temperature profile and forces the gradient to the adiabatic lapse rate, where it would be higher without this effect.
The strength of absorption and emission increases at all levels of atmosphere with increasing CHG concentrations. This raises the limit of visibility from space for all wavelengths with strong or moderate absorption, and in particular around 15 um, where the limit of visibility is highest.
The two effects combine and influence the outcome in the same direction. Lower share of radiation from the lowest and warmest levels and the raised altitude of the layers visible from the space at 15 um lead both to a reduction in the radiation at TOA. To get back to the balance the temperatures must rise and this happens more or less uniformly at all levels from surface to up to the level where adiabatic lapse rate ceases to be reached. What happens beyond this point requires additional analysis, but does not influence strongly the resulting warming of the troposphere and the surface.
As the the altitude of the limit of visibility from space near tropopause goes up and at the same time the temperatures at constant altitudes in troposphere rise, we have to canceling effects influencing the temperature seen for 15 um from the space (radiating altitude effect down and general warming effect up). This leaves it open, whether this temperature will change and if it does, to which direction. The balance may be reached in either case and the result depends on other factors.
Pekka, I am familiar with radiative transfer, and this brings up a problem on this blog where we have to talk to both experts and non-experts. My description was directed in perhaps too simple language, to non-experts. I realize my use of the word “average” was not strictly correct, but it applies to a weighted average in some way. You will find few non-experts that will go through what you just wrote, though accurate, and would prefer simple explanations limited to a paragraph, like I attempt to do on my blog posts.
Jim D,
I knew that you know the facts. When I object to messages of people who know the facts, it is often because I think that they have made simplifications to the extent that they do not answer the questions presented (perhaps implicitly) in previous messages.
One of the common simplifications presented by both sides of the argument in a way that I believe to perpetuate misunderstandings is using a single effective temperature and the lapse rate and pretend that nothing more is needed to understand dominant processes.
My view is that my previous message presents roughly the minimal information needed to reach some understanding and an ability to answer directly to further questions on details. This view refers to an audience that is interested in the climate issue enough to read these discussions. For the first presentation to an audience with no background, that is of course too much.
Significantly, you forgot that word, significantly. The O2 and N2 absorptions are way weak, Factors of 10^-5 and more and can be neglected when discussing the greenhouse effect.
Significantly, you forgot that word, significantly. The greenhouse gases absorptions are way weak, Factors of 10^-5 and more and can be neglected when discussing the Earth mass effect.
The average distance a photon which can be absorbed by CO2 can travel at the surface is ~10 m. Strong enough.
Rob,
I agree with everything in the above.
Cheers
Will
I was glossing over micro processes to get to the main point. But I believe Will was including convective processes as well. The first thread in this series was a long, long, long discussion of a fluid motion approach as opposed to the ‘convective adjustment’ of the IPCC. I don’t think we have the tools or the data to resolve that question. Hence the need for a God’s eye perspective.
The IR spectral analysis is all very well – but such a small part of global energy dynamics.
This is what NASA/GISS say of the ISCCP-FD data – a product of a 2007 re-analysis.
‘The overall slow decrease of upwelling SW flux from the mid-1980’s until the end of the 1990’s and subsequent increase from 2000 onwards appear to caused, primarily, by changes in global cloud cover (although there is a small increase of cloud optical thickness after 2000) and is confirmed by the ERBS measurements.’
The decrease is enormous and the trend is supported by cloud observations over the Pacific – where much of global hydrology originates.
‘In the first row, the slow increase of global upwelling LW flux at TOA from the 1980’s to the 1990’s, which is found mostly in lower latitudes, is confirmed by the ERBE-CERES records. ‘
Apparently, and despite the IR affects of greenhouse gases (which I fully accept), IR flux at toa increased quite substantially.
Climate change was dominated by changes in SW reflectance – cloud changes. This is a confounding issue that a number of people have raised only to be ridiculed and marginalised for their efforts. This is very unfortunate. But, as a Chief Hydrologist, I have a sacred duty to the hydrological truth and will not be intimidated or silenced.
And I bet you haven’t caught up on chaos theory yet either? So drop the superior act and enter into a true dialectic.
CH,
Check out Figure 9.3 of AR4 WG1 Chapter 9. Not only are you correct in your comments about the importance of albedo reduction during the critical heating period, but this IPCC figure shows that none of the IPCC models used in the “Detection and Attribution” studies got close to modelling it. Each GCM had an overestimate of outgoing (reflected) SW of between 1 and 2 w/m2 cumulative over this period – a massive error compensated for by an underestimate in outgoing LW if energy balance was honoured.
Hi Paul,
This compares earlier ISCCP data and not the ISCCP-FD 2007 re-analysis.
http://isccp.giss.nasa.gov/zFD/an9090_SWup_toa.gif – check the trend on that. google ISCCP-FD and it will take you to all the graphs and explanations. It’s a bit hard going.
Now they do use ISCCP-FD data in AE4 s 3.4.4.1 – now I wonder why not in Figure 9.3?
It is beneath the dignity of a Chief Hydrologist to suggest duplicity and I will await a more honorable explanation. Simple human error is usually highly probable – and we should always remember that the human condition applies to us all. I have a good friend who keeps saying that to me. I wonder what she means?
Cheers
Rob,
you might also appreciate the following site:
http://earthobservatory.nasa.gov/IOTD/view.php?id=5484
regards
Günter
Hi Günter,
Dessler 2010 derives what he claims is a cloud feedback for global warming. The method he uses involves surface temperature changes driven by ENSO and changes in CERES fluxes caused by cloud changes.
So keep in mind that clouds respond to ENSO – less cloud for El Nino and more cloud for La Nina.
Cheers
Rob,
I agree. I think clouds are an interesting issue and should be taken on in the blogosphere.
I’d the following question answered.
How can the 20 century warming be assigned, in a scientific sound way, to CO2 or other factors, if the cloud cover is unknown?
Regards
Günter
Hi Günter
We are way beyond not knowing what clouds are doing and it is a foundational error for AGW theory as you suggest.
Check out albedo here: http://isccp.giss.nasa.gov/zFD/an9090_ALB_toa.gif
Check out Professor Ole Humlum’s site for clouds – and lots of other interesting things as well – http://www.climate4you.com/ This is somewhere Judith Curry should link to.
I have a paper here that reviews Pacific Ocean science to go into the question of why clouds vary on multi-decadal scales at least.
http://www.earthandocean.robertellison.com.au/
God bless you.
Rob,
thanks for the link. I should rephrase my question. With it I actually was addressing an answer I got in a different blog, where I posted similar data as yours. One contributor said that the ISCCP-Data are only spurious and not correct. There is even a paper on it, which however is not acknowledged by the ISCCP. In this case cloud cover would be unknown except ground observations, which I understand are very difficult to evaluate.
I should rephrase therefore:
How much warming in the 20th century was caused by cloud cover change and how much by CO2 or other factors? For my opinion cloud cover change has the potential to explain most of the warming at least from 1980 to 2000.
Regards
Günter
Hi Günter,
More like a slam dunk. NASA/GISS statements that are displayed openly on their website. But also – ‘Comparison of decadal changes in ERB with existing satellite-based decadal radiation datasets shows very good agreement among ERBS Nonscanner WFOV Edition3_Rev1, HIRS Pathfinder OLR, and ISCCP FD datasets. ‘
Reexamination of the Observed Decadal Variability of the Earth Radiation Budget Using Altitude-Corrected ERBE/ERBS Nonscanner WFOV Data – TAKMENG WONG et all 2006
I’ve got no idea what the problem is – after they dismiss the ISCCP-FD data – they then move on to say it is not supported by surface cloud observations – as did the IPCC in AR4. This does not seem to be addressing the basic problem that they have – but
Amy Clements and colleagues reported on clouds in the region of the PDO. This was widely reported to be a global warming feedback. The fact is that they reported that there was a negative feedback to SST on decadal scales. Less cloud after the ‘great Pacific climate shift’ in 1976/77 and more cloud forming at the end of the century. Duh.
Burgman et al (2008) did something similar for the entire Pacific. ‘An index of Pacific decadal variability based on a multivariate empirical orthogonal function analysis of National Centers for Environmental Prediction reanalysis is used to extract associated signals in satellite-based measurements of atmospheric parameters.
This index captures the 1976–1977 “El Niño–Southern Oscillation (ENSO)-like” warming shift of sea surface temperatures (SST) as well as a more recent transition of opposite sign in the 1990s. Utilizing measurements of water vapor, wind speed, precipitation, long-wave radiation, as well as surface observations, our analysis shows evidence of the atmospheric changes in the mid-1990s that accompanied the “ENSO-like” interdecadal SST changes.’ There are a few papers – Zhu Ping is especially good – on individual ENSO events – a 20% reduction in eastern Pacific cloud in the 1997/98 El Nino. So you see a patten emerging with multiple strands of evidence converging.
All of the warming in the past 50 years occurred in 1977 to 1998. Hmm – is this adding to the pattern? The satellite record shows most of that warming was in the SW – less cloud is inferred.
Before that it is impossible to tell – but let me run an idea past you. Upwelling of frigid, turbulent, nutrient rich and acidic water in the eastern Pacific is suppressed by a warm surface layer. There is a dynamic balance between surging upwelling water and the warm surface some 100m deep and what could change that? The obvious answer is more cold water pushing up from the poles. Many people have identified a process of ozone warming by UV. Lockwood (2010) identified a long term drift in UV over a century much greater than solar irradiance changes. The UV links into sea level pressure through colder or warmer air in the middle atmosphere – and the rest is history. Storms spin off the polar vortices and penetrate more or less into lower latitudes depending on SLP.
Is there evidence for a long term drift in ENSO? Very much so – including a shift 5000 years ago from La Nina to El Nino dominant conditions that caused the Sahel to dry out.
Cheers
I would note a few things in relation to albedo. Just my thoughts.
1. Global albedo only needs to increase from 0.30 to 0.31 to cancel the effect of CO2 doubling.
2. The estimated variability in albedo is a substantial fraction of this change.
3. It seems albedo decreased in the 90’s and has been increasing more recently, coinciding with consistent global temperature changes.
4. Assigning global warming to cloud-cover reduction negates its potential role as a negative feedback, so it is somewhat opposed to Lindzen and Spencer who expected cloud cover to increase as the world warms (opposite to the 90’s).
5. Some recent studies (e.g. Dessler) say cloud feedback is positive, consistent with these observations.
6. Cloud cover may also increase with reduced solar activity according to some theories. We have been in a period of reduced solar activity recently.
7. Changes in total albedo and cloud albedo may have anthropogenic causes. It is widely believed that the cooling in the NH from the 40’s to 70’s was due to increased albedo from haze and cloud-aerosol effects (global dimming). Could the recent increase in albedo be a second growth due to the industrialization of the next generation of populated countries?
1. Global albedo only needs to increase from 0.30 to 0.31 to cancel the effect of CO2 doubling.
2. The estimated variability in albedo is a substantial fraction of this change.
3. It seems albedo decreased in the 90′s and has been increasing more recently, coinciding with consistent global temperature changes.
Here is the ISCCP-FD albedo. Forget the spikes which were volcanoes.
http://isccp.giss.nasa.gov/zFD/an9090_ALB_toa.gif
Albedo declined from the beginning of the satellite record to the late 1990’s and then increased. It is about a 1% decline. The albedo is a measure of reflected shortwave as a proportion of total incoming. You are better off looking at the total energy picture – LW and SW upward flux plus solar irradiance.
If you look at the ISCCP-FD LW and SW upward flux at TOA – SW declined and LW increased for the same reason – less cloud. But it is the net flux that is important for global warming or cooling. If you care to – there are a couple of explanations here – http://www.earthandocean.robertellison.com.au/
4. Assigning global warming to cloud-cover reduction negates its potential role as a negative feedback, so it is somewhat opposed to Lindzen and Spencer who expected cloud cover to increase as the world warms (opposite to the 90′s).
If the theory doesn’t match the data – ditch the theory. Spencer does some reasonable hack work – but lacks imagination. Someone was talking
the linear mind of the scientist? I heard a neuro-scientist on the radio today saying that scientists have often been inspired by a phase and Einstein did it visually. Interesting – but a digression. I guess by the numbered points – that you are of the linear school. I suggest that you go dancing. Have fun – be creative – get messy.
5. Some recent studies (e.g. Dessler) say cloud feedback is positive, consistent with these observations.
Dessler (2010) correlated surface temperature changes associated with ENSO and CERES flux. Warm = less cloud. Cold = more cloud. But it is really the sea surface temperature. There is a quote from Zhu Ping et al (2007) on the site above describing these broad scale cloud formation processes. Interestingly – they say that the cloud dynamics are different for ENSO than global warming. The changes that Dessler analysed were all driven by ENSO – as he says himself.
6. Cloud cover may also increase with reduced solar activity according to some theories. We have been in a period of reduced solar activity recently.
GCR, magnetic flux, solar activity and ENSO – are all correlatable (is that even a word – it is now) entities. Is it possible to say which causes which? Not really – but I’m going with clouds form over cold water and dissipate over warm. We really know from the sacred hydrology texts that these are interannual, to decadal and millenial phenomenon that determine global climate, hydrology and biology.
7. Changes in total albedo and cloud albedo may have anthropogenic causes. It is widely believed that the cooling in the NH from the 40′s to 70′s was due to increased albedo from haze and cloud-aerosol effects (global dimming). Could the recent increase in albedo be a second growth due to the industrialization of the next generation of populated countries?
The cooling was global and absolutely connected to sulphates. Wild has done some interesting work. Chylek (2009) offered the interesting observation, however, that sulphates could not be the whole story because there is no reason to suspect that sulphates could amplify cooling in the Arctic by so much.
There are all these indices that show interranual to decadal in the instrumental record. The Atlantic Multi-Decadal Oscillation is one getting much attention in the Northern Hemisphere just now. Oscillation this and cycle that. Don’t believe it for a moment. All of these modes of change interact globally in a mad and chaotic dance.
‘These standard bearers of doubt engage in a global dance.
Occasionally, they pirouette towards a grand crescendo and,
then fly wildly to the ends of Earth in a new choreography,
Tremendous energies cascading though powerful systems.
Unless I miss my mark then this is the mark of chaos and
a danger in its own right as climate system components
jostle unpredictably and things settle into whatever pattern
emerges – mayhaps a cold, cold, cold day on planet Earth.’
from “The Song of a Climate Zombie”
No – the increase in albedo after 1999 was caused was caused by cold water rising in the eastern Pacific over which cool cloud formed. This is likely to persist as a cool La Nina mode of the Pacific multi-decadal pattern intensifies over another decade or 3.
After that, I think it is anyones guess. The new scientific consensus is that both weather and climate are chaotic. In a chaotic climate – predictability and risk are two sides of a coin. Climate predictions can only be made in terms of probabilities and climate risk from anthropogenic greenhouse gas emissions is mathematically certain as a result of those same probabilities.
Rob (CH)
-When you or others say the albedo anomaly changes by 1%, is that 1% of 30% which is really 0.3%? I have always been confused with this terminology.
-You will see from GISS, for example that the NH cooling in the 40’s to 70’s was much stronger than the SH, even reversing the warming there, while the SH kept warming.
-If the recent extra clouds are due to colder Pacific water that is a kind of positive feedback. Can we expect global sea-surface warming to have a similar positive feedback by reducing cool-water cloudy areas? It is not entirely out-of-bounds to relate ENSO cloud cover changes to global warming changes (as Lindzen also likes to do), but I agree it may be a stretch.
– Anyway I say the recent increase in albedo could be anthropogenic too, until shown otherwise. This needs more information about the distribution of the albedo change.
My mommy told me not to talk to people who say DIALECTIC.
The Chief Hydrologist has special dispensation. It is the seeking of the hydrological truth through dialogue. For this the required attitude is humor, patience, good will, honesty and good faith.
It seems that the black body theory about the earth’s base temperature (sans GHG, etc.) without adding that the earth also adds its own core produced heat to the equation is missing a component. How much does this background heat factor into the temperature of the oceans and continents?
Just a thought – that I haven’t the time (or mathematical skills) to explore but wanted to toss out in the ring – seemed overlooked to me.
It rang a bell – there was someone who included friction and geothermal energy. Then I remembered – the Polish guy who claimed basic physical principles which weren’t but then were claimed to be based on radiosonde data which couldn’t possibly be accurate enough to prove invariant optical depth. For God’s sake – don’t go there. Other than that – if we are looking at change it is fairly constant and therefore doesn’t figure in climate change.
less than a tenth of a Watt per square meter compared to solar insolation of a few hundred Watts per square meter.
Does the greenhouse effect (GHE) warm the surface or merely reduce the cooling?
Answer: THE GREENHOUSE EFFECT WARMS THE SURFACE. IT DOES NOT REDUCE THE COOLING.
Conclusion: The phrase “the GHE reduces surface cooling” should be abandoned. It is always misleading and sometimes completely wrong. What is accurate, however, is to state that the GHE warms the surface.
Because my argument is partly semantic (but only partly so), I respect the views who wish to retain the “cooling” concept while fully understanding the true dynamics involved. I will try to persuade them, however, that it is better simply to refer to the ability of the GHE to warm. Here is why.
First, consider a hypothetical Earth without greenhouse gases, but otherwise like our own. At equilibrium, its temperature will be colder than ours. It will neither be cooling nor warming – the net flux at the surface will be zero. What happens if we add CO2 or other GHGs (we’ll assume nothing else changes)?
The back radiation from the atmosphere will now cause the surface to warm – i.e., its temperature will rise. Was this because it reduced the cooling?
I will now propose a theorem of profound and revolutionary significance that should forever alter our view of the universe: YOU CAN’T REDUCE THE COOLING OF AN OBJECT THAT ISN’T COOLING.
In our hypothetical example, the Earth wasn’t cooling, and so the rise in temperature was simply a warming, by any reasonable definition of warming.
“Wait a minute”, someone will argue. “The net flux was zero before adding the GHGs, but can’t we divide it into a downward (“warming”) flux and an upward (“cooling”) flux? Didn’t the GHGs reduce the upward cooling flux?”
The answer is: No, they didn’t reduce the upward flux. They increased it. A warmer object emits more IR upward, and so the warming Earth will increase its upward IR emissions. If one wants to look at it that way, we would have to say that GHGs increase surface cooling as a result of their warming effect.
Now let’s proceed from our hypothetical world to the real one. When the sun rises, the Earth starts to warm. How much depends on the concentration of GHGs. If the concentration is higher, more radiation will return Earthward, and the surface temperature will increase more than it would with a smaller GHG concentration. Because the Earth is warming, and more GHGs magnify the warming, they are heating the surface.
At night, the Earth does in fact start to cool – the net upward flux exceeds the downward one. Here, the net effect of the GHGs is such that the cooling is less. Technically, therefore, one could state that they are reducing surface cooling at night. However, I would still suggest that the explanation is misleading. The reduction is achieved via the warming effect of the GHGs, which partially offsets loss of heat to space. The misleading element of the “reduced cooling” explanation is that it creates an impression that the back radiation from GHGs can in some mysterious way instruct photons emerging upward from the surface to turn around and go back where they came from. Of course, that doesn’t happen. In the presence of GHGs, the upward flux increases rather than declines (see above), and so at a molecular level, with each flux evaluated separately, both warming and cooling fluxes increase, with the warming increase exceeding the cooling one. There is no reduction in the cooling flux analyzed separately.
Finally, it is possible to ignore total sources of radiative energy and state that when IR alone is considered, the net flux is always in an upward (“cooling”) direction, and that imbalance is reduced by GHGs. It’s not clear why the other sources shouldn’t be included, but if we exclude them, GHGs can legitimately be said to reduce the cooling IR flux.
Not always, however. In regions where most surface heat loss is due to evaporation, downward IR will exceed upward IR, and so the IR net flux is a warming one.
All in all, it seems reasonable to avoid invoking cooling when explaining GHE effects. Simply referring to surface warming is accurate and avoids giving the wrong impression.
One can correctly argue, of course, that GHGs reduce the rate at which IR escapes to space. This is in fact why they are a potent warming influence. At the surface, where the warming/cooling concepts are invoked, their effect is to warm, and to increase rather than reduce the upward flux.
Also, in anticipation of further challenges – Yes, GHGs reduce the net upward IR flux by returning some flux downward. However, when the surface is warming rather than cooling, it is misleading to refer to that as reduced cooling. In accordance with Moolten’s Law, stated above: You can’t reduce the cooling of an object that isn’t cooling.
Fred,
When did you stop beating your mother?
An object is cooling if it is losing energy.
An object is warming if it is gaining energy.
Unfortunately you state that objects can gain and lose energy at the same time. This tends to obfuscate things instead of taking the net which is clearer.
The GHG’s return less energy than the earth loses. GHG’s COOL. The sun sends more energy than it receives from the earth. The sun HEATS.
Either way you go there is NET.
If you want to claim that GHG’s add to the NET heating during the day that might be appropriate. Talking about GHG’s by themselves it is not. Of course at night it is different isn’t it. You would then have to say GHG’s add to the NET COOLING!!
It is really that confused when you make it that way..
Fred,
Looks to me like an Orwellian proposition.
However, I think it is the usual convention in atmospheric physics to calculate and measure the IR cooling rate and the solar heating rate. The difference is the net heating/cooling rate depending on the respective sign. I do think that is a convenient and practical concept, which implies that downwelling longwave radiation reduces the IR cooling rate.
Regards
Günter
Does the insulation covering a hot water tank warm or “heat up” the water?
Of course it doesn’t.
A warmer object will always radiate more of every wavelength than it absorbs.
How then can radiation from a colder object be viewed other than radiative insulation!
The insulation acts to reduce conductive and convective heat loss, whereas GHGs warm by reducing radiative heat loss at the top of the atmosphere, but otherwise the principles are similar. Neither the insulation nor the GHGs are the heat source – for the tank, it’s the heating elements, and for the atmosphere, it’s the sun.
Everything cools at night. A corpse with a blanket cools at night. The contents of a thermos flask cool at night. Nothing warms at night because there is no heat source to provide warming at night. Every sensible person knows this. It’s not semantics. It’s normal common sense. Time, Fred, for an overdue semantic decoke?
See my explanation above.
Fred,
A cooling or heating rate in radiative transfer theory is the divergence of radiant energy fluxes and therefore always a difference between at least two fluxes. In the simplest case, in the two-stream approximation, at least the difference between the over the hemisphere integrated upward and downward fluxes.
The IR-cooling rate is never zero on earth. We have always a positive net IR-flux in the outward direction.
The net cooling/heating rate is zero in a stationary state. We start with such a stationary state and increase the greenhouse gas concentration.
On the night side the IR-cooling rate equals the upward IR flux minus the downward IR-flux. The shortwave heating rate is zero. The net cooling/heating rate therefore equals the IR-cooling rate and is a cooling rate. The downward IR-flux increases with increasing greenhouse gas concentration, the IR-cooling rate decreases and therefore the net cooling rate.
On the day side the IR-cooling rate equals the upward IR flux minus the downward IR-flux. The shortwave heating rate is the incoming solar radiant energy minus the outgoing shortwave radiant energy of the earth, the last is zero. The net cooling/heating rate equals the solar heating rate minus the IR-cooling rate and this is a heating rate. The downward IR-flux increases with increasing greenhouse gas concentration, the IR-cooling rate decreases and therefore the net heating rate increases. An increasing net heating rate leads in turn to a simultaneous increase in temperature of surface and atmosphere, which in turn increases upward and downward IR- radiant energy fluxes until the net heating rate is zero again.
You can of course add the downward IR radiant energy flux to the incoming shortwave flux. However, you have to realize that this is not a heating rate according to radiative transfer theory, but rather the sum of two radiant energy fluxes in the same direction. You only get the net heating/cooling rate, if you substract the upward flux.
One has to acknowledge that the upward and downward fluxes are happening simultaneously and that a separated flux of radiant energy is neither a heating nor a cooling rate in radiative transfer theory. I consider it therefore incorrect to attach the verbs cooling or heating separately to such separated energy fluxes from a physics point of view.
I like the radiative transfer theory, its definitions and I think it works perfectly well as it is.
Best regards
Günter
Günter,
No official or standardization body has to mu knowledge defined what is The Radiative Transfer Theory or the right way of talking about it. It is fully clear that different people have different ideas on the way of describing the same physical processes. I cannot expect that you prefer the same expressions as I, and you cannot require from me the same use of expressions that you prefer. The textbooks are not uniform on it and different formulations appear most natural and understandable to different people.
That all is a fact of life and makes communication a bit more difficult, but that should not be a major obstacle in discussions between people who want to understand each other and who want to spread correct understanding of physics.
The sad thing is that in these discussions we have also participants who do not want to understand what others are saying – or in many cases do not want to indicate that they have understood it. They do not want to help in spreading correct understanding of physics, but they want to undermine this activity and use the ambiguities in use of words as a tool in spreading confusion.
Readers may have their own lists of people, whom they suspect of purposeful spreading of confusion. I have my own list of strongly suspect names and pseudonyms, but I do not give it, as I may have erred on one or two of them.
Pekka,
Thank you for the hint. I reread Fred’s argument again and I understand him better now. I understand that my argument about the IR-cooling rate, I took from K.N. Liou’s book “An introduction to atmospheric radiation” is also a questionable separation of fluxes. Maybe we can agree to consider always all the fluxes through the indicated surface simultaneously , that is the right way anyway. In this case we can compromise on the following wording. An increase in greenhouse gases increases the net heating rate at the surface and in the atmosphere on the day side. I will of course always object to isolated notions, like “backradiation” is warming the surface.
However, I think it is wrong to keep a list of people and to suspect that people want to spread confusion. I had a different impression of you and am now a little bit disappointed.
Well, but I keep no grudge. So, I will still enjoy your contributions to this blog.
My understanding of science calls for an exchange of arguments and a precise language. I do not think scientific understanding and education is enforced if one compromises on scientific precision. Although I admit it is not always possible in a few sentences in such blogs.
Best regards
Günter
Günter,
Some people do write messages that they know to misrepresent facts. That happens on the internet all the time, and do not believe that this site is completely free of the problem. That has nothing to do with trying to learn more on the issues or with legitimate differences of opinion. Of course there is always a risk of mistake, when one makes guesses on who is doing that and who just writes in a suspect style. Therefore I do not tell names. Without any attempt to judge the opponents, I could hardly keep on discussing in more reasonable ways very long. Some recent cases led me to the decision of raising this issue in my messages.
Science calls for precise expression whenever there is a risk of misunderstanding. There are, however, problems, when the normal use of words has deviated from formal definitions. The concept of “heat” is a good example. It is first of all a common word outside science with a reasonably clear meaning. It is used by scientists end engineers in nearly same meaning as lay people use it. The classical thermodynamics has, however, a formal definition that is more restrictive. In this case I would say that the problem is with this restrictive definition, not with the common usage. Now some people use the formal definition as a wrong argument in discussions, where others use the word in its normal meaning.
This is not the only concept related to science that is used widely in argumentation in a way that I find wrong. The problem is in the same direction. Non-scientists insist on formalities and attack science based on deviations from their stated requirements. This is done in situations or in ways that do not relate to actual problems of science. The arguments are instead used to discredit perfectly valid scientific understanding.
Pekka,
I have a different experience and therefore opinion. I heard very often at university, people saying that they don’t like classical Thermodynamic, because of its axiomatic nature. But this is the way classical thermodynamic is. I sympathized at times with this notion, but I did have to learn thermodynamics twice at first in my undergraduate studies in chemistry and later on during my graduate and postgraduate studies in physics. I had an excellent teacher and so I began to like thermodynamics and I still enjoy it. However, I do know that many people still dislike it because of the axiomatic nature. However, my experience is that classical thermodynamics is a beautiful consistent field that is only useful if you stick rigorously to definitions and pay attention to detail. If you do so, you can explore a lot of things in nature with thought experiments “Gedankenexperimente”. Sticking to definitions brings you new insights in thermodynamics and nature.
If you don’t pay attention to details and definitions, you don’t get a useful result of your “Gedankenexperiment” or even misleading results. Moreover, any scientific model needs to be thermodynamically consistent.
Therefore I disagree with you. If one uses the word heat as a scientist or a teacher, I think one should pay attention to detail and stick to the thermodynamic definition. But this is only my recommendation and everybody need to choose for himself.
I have also made a different experience in the blogosphere. Because I try to stick to the thermodynamic definitions, I usually have to defend at the blog EIKE in Germany the greenhouse effect against the wrong statement of G&T that the greenhouse effect violates the 2nd law. In this discussion I usually use the word heat in its formal definition and explain that the sun is providing low-entropy energy to the open system earth and therefore there is no way the 2nd law is violated. This is a useful line of defense using the power of classical thermodynamics in a thought experiment that describes the greenhouse effect with an analogy of everyday experience.
So I do think sticking to the formal definition is the best way a scientist can choose
And now here I get critic, since I remind somebody that heat has a rigorous definition in thermodynamics and physics in general during a scientific discussion.
.
I also disagree with your last sentence about the attack on science. Science can counter such formal attacks easily, if one admits the formal error and corrects it. This is the way to go in Science.
However, I do think that formal error in definition should not be used as an attack, but whoever spots this formal error of definition should notify the author, so that he can correct it. Again, whenever I notified somebody in a blog about such an error of definition I got many responses from I do not understand physics to I try to distract from the real problem. So judge for yourself, the reaction of scientists? Nobody can be discredited in a scientific debate, if he made an error and corrected it. One can only be discredited as a scientist by making an error and not correcting it.
Of course human beings make all kind of “ad hominem” attacks in the climate debate. This is true for both sides of the discussion.
Best regards
Günter
Günter,
I have nothing against classical thermodynamics – except that it is much less powerful than statistical mechanics combined with quantum mechanics and other physical theories.
It is all right to use precise terminology, but it is not alright to spread wrong claims through misinterpretation of the message that others are telling, when they use words in the meaning they are commonly used, but differently from some formal definitions.
Concerning science, good scientific practices do not in reality follow such strict rules that have been presented in many places. In particular Popper has presented a too narrow interpretation of science. This is not only my opinion, but a widely (although perhaps not universally) accepted view (stated explicitly also by Judith Curry). Popper’s words are regularly used against perfectly good science. There is no way science could be changed to follow too formal rules without essential loss in its productivity. Good science covers many more situations and methodological choices than any precise rules. Good science is something that can be recognized, but not predefined.
Pekka and Günter
I hope you dont mind my intrusion on your debate.
I dont know if Pekka has had a less restrictive introduction to classical thermodynamics than I have had.
Günter, like you I would have failed my degree examinations if I had adopted a free and easy interpretation of words like heat.
Its a pity that this site does not have graphical facilities or I would ask Pekka to describe the Carnot cycle with total vernacular freedom but missing the word heat.
Apparently statistical mechanics combined with quantum mechanics and other physical theories are much more powerful than classical thermodynamics.
But if we have free and easy definitions for thermodynamics then why not for statistical mechanics and QM.
As long as we have a verbal preamble about what we are trying to say then with a little sympathetic understanding from our audience perhaps some of what we say will make sense.
However if someone was inclined to apply the idea of falsification to my free and easy theory, then that too would be unnecessarily restrictive.
Really what I gather is that these powerful new theories tell me that everything is just a matter of opinion.
A reality check is in order here.
What the public are beginning to observe is that Climate Science has some very odd features.
A “greenhouse theory” which has little in common with a greenhouse.
Where snow and ice with low temperatures are another proof of AGW.
Where the withholding of data from critics is held to be a virtue.
Where cut and paste graphs to hide declines are tolerated.
Where active steps are taken to stop publication of any views which question the IPCC approach.
Perhaps if Climate Science stays at this level then let heat mean anything to anyone.
However the one point on which I disagree with G&T is that I think Climate Science is an interesting and important branch of science.
However given its history a lack of rigour is the last thing it needs.
Brian,
” What the public are beginning to observe is that Climate Science has some very odd features.
A “greenhouse theory” which has little in common with a greenhouse.
Where snow and ice with low temperatures are another proof of AGW.”
As a general public, they are beyond belief!
“Where the withholding of data from critics is held to be a virtue.
Where cut and paste graphs to hide declines are tolerated.
Where active steps are taken to stop publication of any views which question the IPCC approach.”
As a general public, I found them beyond manipulation using mostly public fundings. They owe us, the general tax payers!
Climate Science stays at this level, as a general pubic, I find them very disappointed as “Science” with very low level of trust and very low level of respect!
Bryan,
no I don’t mind. Of course a scientific model or thought model about the natural world has to be thermodynamically consistent. I think we agree here.
I have seen this in grad students and at work as an engineer, if you don’t learn and don’t stick to the definitions of your field and of physics or chemistry, the quality of your work and your teaching pretty soon gets down the train. Grad students get the impression that they can use any interpretation, they can think off, to explain the data. If there are no restriction and rules like “thermodynamically consistent”, we would have no scientific progress and a scientific discussion is useless, because you can present anything as a conclusion. A grad student once proposed to me a reaction mechanism with a nitrogen atom with five valence bonds, which explained the data very well. When I told him, but the model is wrong, because nitrogen with five valence bonds does not exist, he showed me a peer-reviewed paper. So, yes I agree.
I also think this argument about QM and statistical mechanics is useless, I did hear it always from grad students who didn’t like to learn the ropes of classical thermodynamics. Yet, I have not seen a statistical mechanics or quantum mechanical arguments in the climate debate and each book about meteorology starts with a chapter of classical thermodynamics
And I also agree with the second part of your last sentence:
A lack of rigour is the last thing climate science needs.
And that climate science is an interesting topic.
But I disagree on some point with “Given its history”. I do not think that climate science in general should be judged on the poisoned discussion in the internet and the media. This would be unfair and also incorrect.
But again, I agree. A lack of rigour is the last thing climate science needs.
Regards
Günter
Pekka,
As I said. I disagree with all my heart, because my experience is different, at university and at industry.
For me it is the opposite. Good science or engineering cannot be recognized, if science allows a free interpretation of basic concepts.
Good scientific and engineering practice in reality actually follows strict rules.
There is no productivity, if one presents a model or a conclusion in a report that is derived from loose definitions.
No way and no use, because one cannot trust it.
I have nothing against lab slang, but once you publish your paper, prepare your talk or lecture or publish your report you have to pay attention to detail, rules and definitions.
As Bryan said: A lack of rigour is the last thing science needs.
But this is only my opinion.
Best regards
Günter
Günter,
I do not propose sloppiness in science, certainly not. I do not either propose that one should not be very careful with the definitions, when one applies classical thermodynamics, or studies mathematics. I have extensive studies in both and also extensive teaching experience. As a young lecturer I may have been even too formal, when giving courses of quantum mechanics. I have also written numerous scientific papers, many of them on theoretical physics which was my first area of research, and I know that one must be very careful with details, when doing that. I have been close to both basic and applied research all my carrier and base my statements on observations on what I have seen to lead to best science and scientific progress.
There are good practices and bad practices and there are practices that every scientist should follow (but some of the greatest have not followed, at least not formally). It is, however, a fact that all rules have been written having a limited view of all situations where science may lead. That this happens often in the most valuable phases of research is also typical for science and the reason that the greatest scientific results are often developed stretching the rules is related to this.
A research professional must follow rules strictly, a good scientist must be honest and cannot be sloppy, but he or she may be led to stretching the rules.
The aim of science is to learn about the reality. Science must analyze and present openly factors supporting the claims and remaining problems with them. How this is best done is case dependent and it is not possible to write rulebooks for that. Building up and presenting evidence in favor and against conclusions is essential for science. Replacing these general requirements by fixed and formalized rules is not the same thing.
The sad thing in climate discussions is that mispresentation of requirements for good science is used as argument against good science. Of course it is used also against bad science, but the lack of selectivity makes such critique to have little real value.
Pekka,
well I don’t think we disagree to much about science in general. However, the definition of heat and energy is not a formal rule within physics, but a necessary thing.
But I think both opinions that we expressed need to be put together and put to use. I do think in any science or engineering work there is no control, if there are no borders, rules, limits or definitions. However, I do also think it is valuable and the scientific way to probe beyond the borders and change rules and definitions. But this needs to be done in a controlled way and not arbitrarily in any discussion. I think if everybody communicates his definitions clearly, we can have a more useful discussion and learn something.
I once had a discussion with a climate scientists, who did not know that cloud radiative forcing has a different definition in the IPCC – Report compared with radiative forcings for greenhouse gases. It took us awhile to get on the same page.
In order to do better, one needs to communicate the definitions one uses, when explaining a line of argument. Within one line of arguments the definitions must not change. Between two discussion partners the definitions need to be agreed upon. That is a necessary prerequisite of a scientific discussion.
One can only follow a conclusion, if all assumptions and definitions that are needed are presented and explained. The same is true for evidence. Evidence is valuable only if the measurements are controlled and the conditions explained.
So, if somebody hints that the borders and definitions are allowed to be loose, it rings a bell and I object in order that he clarifies his definitions.
I do not share your concern about the sad things you mention. I think it is your projection trying to assume things about other people. I would recommend not to do that.
Regards
Günter
…”The insulation acts to reduce conductive and convective heat loss,”….
The insulation also reduces radiative heat losses.
Yes, that’s true.
Because its designed with a low-emissivity material?
Ken Coffman
…..”Because its designed with a low-emissivity material?”…..
I did not specify the emissivity.
However Kirchhoff tells us that if the material absorbs radiation it will also emit radiation of slightly lower magnitude since the inner surface is likely to be at a slightly lower temperature.
I look on this as radiative insulation.
Fred,
I do think you can always imagine a room with a heating water cycle with hot water and a cooling water cycle with cold water.
So you can always say if I reduce the flow of the cooling water, the room gets warmer.
But what is the mechanism behind it? Due to the reduced flow, the cooling water gets warmer simultaneously with the room. Simultaneously the “backradiation” from the warming cooling water will also increase. But you will know it is the reduced flow of cold water that is the root cause for the room getting warmer and not the “backradiation” from the warming cooling water.
Regards
Günter
That’s very different from the atmosphere/surface relationship. For the latter, the surface experiences what would be the equivalent of an increase rather than a reduction in the cooling water flow rate. The warming is due to the fact that warming cycle increases even more. I realize that “reduced cooling” is the conventional description, but I believe it’s misleading for the reasons I’ve cited above. In any case, I hope anyone interested will go back and read my earlier comments, because otherwise they won’t understand what we’re talking about.
Fred,
I don’t think it is very different. “Backradiation” is “backradiation”. In both cases you have a constant heat source and the root cause for the warming of the whole system is the reduced cooling rate across the system boundary and in both cases increasing “backradiation” is not the root cause, but the effect of simultaneous warming.
Regards
Günter
My best response is to invite anyone interested readers to read my earlier comments.
Dear Reader – if any still persist. My earnest advice is that it is better not to.
“I will now propose a theorem of profound and revolutionary significance that should forever alter our view of the universe: YOU CAN’T REDUCE THE COOLING OF AN OBJECT THAT ISN’T COOLING.” Fred
See – I ignored my own advice and now I’m sorry.
I second your opinion, chief. What a sad ignorance is breeding and flowing around, unbelievable.
Hi Al,
May I be permitted to mildly admonish you? Although I am conscious of the log in my own eye and will share the admonishment.
“Within a man of light, there is light, and he lighteth up the whole word. If he does not shine, he is darkness.”
Ignorance is only countered if we shine our unblinking light across it. Here, it is seeking of the truth through dialogue. For this the required attitude is humor, patience, good will, honesty and good faith. If others have less of those qualities – it is nothing to do with you and your light will suffer if you respond in kind.
Have fun – take chances – get messy – but don’t be deliberately unkind.
And I apologise to Fred if that is how I appeared.
Cheers
Chief,
off on a tangent here – looks like you are a fan of the Magic School bus ! (for those who may not know, it is a show for kids about science and learning, and the phrase ‘Have fun – take chances – get messy’ is used a lot during the ‘field trips’ where the kids learn about all sorts of things. )
HEY, maybe there needs to be an episode on the ‘green house theory’ and ‘backradiation . . ! :-)
Hmmm – I got it second hand from an American mate – I will ask him about it.
Cheers
Thanks Chief.
I almost wrote a long post about a deep, yes revolutionnary insight that : x>y => x-y>0 but your advice prevented it.
So I am afraid that everybody will have to live without it.
There is actually a difference, the thermal boundary condition of the heat source is T = const, which is different from the earth, where dq/dt = 0. We could replace the heating water with an electrical coil that provides constant energy flux, dq/dt = 0.
OK, bottom line time, Hertzberg does not understand Kirchhoff ‘s Law, and in particular how emissivity and absorptivity are equal at the same frequency. Thus his entire paper is fallacious (Eli is being kind).
BTW Gerhard is revolving in his grave after seeing this paper.
Eli
Would you be a kind Rabett and give me your best estimate of how many thousand metric tonnes of Co2 need to be emitted into the atmosphere in order to raise surface temperatures by 1 degree Centigrade? Presumably we need to take into account that around 50% will become absorbed into one sink or other before it affects actual concentrations.
Thanks a lot
P.s Theres no trick!
tonyb
ScienceOfDoom and others are a long way off the mark when they think they can apply Kirchoff’s Law in the manner they do to the surface of the Earth. \
So let’s look firstly at what Wikipedia says …
“A body at temperature T radiates electromagnetic energy. A perfect black body in thermodynamic equilibrium absorbs all light that strikes it, and radiates energy according to a unique law of radiative emissive power for temperature T, universal for all perfect black bodies. Kirchhoff’s law states that:
“For a body of any arbitrary material, emitting and absorbing thermal electromagnetic radiation in thermodynamic equilibrium, the ratio of its emissive power to its dimensionless coefficient of absorption is equal to a universal function only of radiative wavelength and temperature, the perfect black-body emissive power.”
OK. Note the perfect blackbody requirement. Can we fully adjust by simply bringing in a constant (like 98% or similar) to allow for the fact that the surface is not perfectly “black” so to speak?
No. That is not the issue. The surface is not perfectly insulated – a fundamental assumption in blackbody theory. The surface is not surrounded by space: it has air above and more water and solid crust below. Thermal energy is conducted or diffused out of the surface, and some is also transported by evaporation and chemical processes.
In fact, the diffusion (molecular collisions) between the surface and the first millimetre of the air tends to maintain very close thermal equilibrium, at least in calm conditions.
When this is the case, there is very little radiation at all – nothing like the amount a perfect blackbody at, say, 255 deg.K would emit. Most of the radiation comes from the atmosphere, and that temperature is a mean which would be found somewhere in the atmosphere. In fact it also is way out because of variations between day and night, but that’s another matter.
Radiation coming into the surface which has frequencies above its emitting spectrum (ie solar SW insolation) is not re-emitted but instead its energy is converted to thermal energy which is stored until it may subsequently leave the surface by various means.
A small amount of radiation which is received and which also has frequencies within the surface’s emitting spectrum will be re-emitted with the same frequency and intensity, although some of it can be converted to thermal energy, especially if it has frequency close to the emitting peak frequency of the surface, as determined by Wien’s Displacement Law. As this thermal energy can exit by means other than radiation, Kirchoff’s Law does not apply accurately because, as explained above, the surface is not an insulated blackbody.
Radiation which has much lower frequencies again (ie from the colder atmosphere) is also not converted to thermal energy and is either re-emitted as is, or deflected, the net result being equivalent to reflection.
Such radiation (including so-called “backradiation”) can have absolutely no effect on the surface – neither warming it nor slowing the rate of cooling.
(continued)
Some will say that there’s no problem because, when we apply S-B law we subtract the radiation in the other direction and it’s only the net radiation that’s small.
Well, just because we do in fact subtract a mathematical term which would indeed be the same as that for a blackbody at that slightly lower temperature and get the right result – this does not in itself create the radiation in the reverse direction, nor prove its existence just because it gets the right answer. What’s to stop the radiation just being less in the first place? After all, most of the energy has already left by other means in the case of Earth’s surface, so there’s not enough left to radiate a large amount.
Another way of looking at it is to imagine that the second “body” is pure oxygen which is butting up against the surface and which has temperature, say, 1 degree less than the surface. Now Quantum Mechanics tells us that oxygen certainly cannot radiate a large amount at surface temperatures. So how could there be all that radiation back into the surface in such a situation? There isn’t.
So why do instruments appear to measure a lot of backradiation? Well, there can be hot spots in the atmosphere that might radiate something towards the surface, but, in general the explanation lies in the way instruments like IR thermometers actually work. Wien’s Displacement Law tells us absolute temperature is proportional to the peak frequency emitted, and so, by measuring frequency we can calculate temperature. But it is wrong to assume that, just because a certain “surface” of gas in the atmosphere has any particular temperature then it must be radiating an amount which S-B says a perfect, insulated blackbody would do. Any air molecules have plenty of other air molecules at similar temperatures all around them, so they are far from being insulated. They can lose some of their energy by collisions before radiating it anyway.
The only way to measure any DLW radiation is to measure its effect in warming some physical object. If it were doing so then you would think such experiments would abound. Show me just one while I sit watching the frost on that shady spot of ground hanging around all day long – frost which the Sun could have melted in less than an hour.