- Back radiation is a phrase, one that I don’t use myself, and it is not a word that is used in technical radiative transfer studies.
- The argument is made technically from the spectral infrared absorption and emission of CO2 and other gases.
- Lets lose the back radiation terminology, we all agree on that.
This is a stunning revelation, because CO2 alarmism is based on massive back radiation as the carrier of the greenhouse effect. If back radiation is a phrase, so is CO2 global warming. A phrase, not science. The difference is huge.
What made Judy change her mind? Was it the debate on her blog on my chapter in Slaying the Sky Dragon showing that back radiation is not physics, because it is unstable?
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Good job distorting Judith Curry's quote. It certainly is a "stunning revelation" into your own credibility in both science and reading comprehension.
SvaraRaderaRunaway Global Warming is Scientific Hysteria
SvaraRaderaIt is because, as famously illustrated in the Kiehl and Trenberth "Energy Budget" diagram, backradiation comes at the price of a gross violation of conservation of energy. But you are right, their error cannot be waved away as mere words, as Curry and other consensus defenders want to do.
I think you can´t deny that the earth surface gets warmer with than witout CO2 in the atmosphere, so "CO2 global warming" is not just a phrase. CO2 is a "greenhouse gas" like water vapour and other gases. But how much it contributes to the warming is an open question. You agree with me?
SvaraRaderaWhat did I distort?
SvaraRaderaTo Lasse H: It is not even clear that a little more CO2 causes warming. How come that you are so sure?
SvaraRaderaThis time I agree with Curry. Let's get rid of the backradiation, the cartoons and all playing with words, and instead start to do some real science based on mathematical language. That should suit you since you are a mathematician.
SvaraRaderaShould we get rid of the greenhouse effect as well, and get to real science?
SvaraRadera"showing that back radiation is not physics, because it is unstable?"
SvaraRaderaYou keep on saying that the standard picture is unstable but you still have not provided us with any mathematics proving it.
Please, do not waste your time writing rhetorical blog posts when you have real science, i.e. mathematics, to do. Rhetorics is for politicians and theologians, not scientists.
Why not! There are still unresolved questions out there.
SvaraRaderaThe Kiehl-Trenberth "cartoon" was, in my understanding, peer-reviewed science:
SvaraRaderaEarth's Annual Global Mean Energy Budget, Bull. Amer. Meteor. Soc., 78, 197-208 (1997)
Yet it is garbage, pure and simple, as is the greenhouse effect:
Venus: No Greenhouse Effect
The "greenhouse gases" do what every other gas in the atmosphere does, heat the atmosphere by direct absorption of incident solar radiation (mainly ultraviolet in the stratosphere, infrared in the troposphere). Adding more "greenhouse gas" in the troposphere only increases the efficiency of heat transfer by infrared radiation in the atmosphere; this enables the dark side of Venus (with almost pure CO2 atmosphere) to be as hot as the sunlit side.
I have shown that my model with transfer of heat energy from warm to cold is stable, just because it describes transfer of heat energy from warm to cold, which indicates that a model with transfer from cold to warm is unstable, like the backwards in time heat equation. If you say that the "standard picture" is stable it is up to you prove that it is.
SvaraRadera"which indicates that a model with transfer from cold to warm is unstable"
SvaraRaderaWhy? Why would the stability of one model imply that another is not stable?
Let us take the simple model which says that no heat is transferred at all. That model is completely stable. It is obviously flawed in other respects but that has nothing to do with yours or any other model, only the fact that it does not agree with reality.
Nothing you say about your own model will imply that another model is not stable, not even indicate it. Likewise the stability/instability of the standard model says nothing about the stability of yours.
The standard picture is nothing like the backwards in time heat equation. The standard picture is one where several bodies absorb and radiate energy, following Planck's law. It is a diffusion model, not a backwards diffusion.
Even more crucially what you need to show for your own model is that it can deal with time dependency. In particular, how will the model handle two very distant bodies in vacuum where the colder body is suddenly heated to become the warmer one?
It is a simple and easily arranged situation, and if your model cannot be used for it then the model is not a physical theory.
You continued refusal to provide mathematical analysis of your own model makes it look more and more like you have stopped being a scientist and instead become a politician, which would be very unfortunate.
My model is time-dependent, and so is the analysis although it focusses on the time-periodic case as the basic case of interest. Suddenly appearing suns is rather exotic. Your version of Planck's law is ad hoc and nothing Planck gave to the world.
SvaraRaderaClaes said;" It is not even clear that a little more CO2 causes warming."
SvaraRaderaBut water vapour causes warming so why shouldn´t CO2 cause some warming though a little less. I think you admit that there is some extra warming of the earth depending of "greenhouse" gases. About 30 degrees?
No, the + 33 C is a result of combined thermodynamics and radiation, not radiation alone. It is impossible to say what the net effect of CO2 doubling will be, the only thing which can be motivated is that it is small.
SvaraRaderaBut with radiation only it should be even more than +33 C. I suppose that the thermodynamics (convection,...) cool the earth. You have to compare the temps with and without the "shelter". Yes it is a question of how much the CO2 gas contributes. But that will be discussed for the coming 50 years.
SvaraRaderaA simple example of "background radiation": car windows will not get frosty under a roof (open at sides) in a clear cold winter night. Without the roof they will.
OK, we agree that the effect of doubled CO2 is unclear. There are 10 different arguments indicating that it should be smaller than 0.3 C, while
SvaraRaderathe 3 C by IPCC lacks scientific support.
It looks like you decided to censor my previous comment where I asked you to provide the mathematical analysis needed to show that you really have a physical theory.
SvaraRaderaI thought you were someone in favor of polite scientific discussion but it looks like I was wrong.
Maybe I missed it. In any case, the model and analysis is time-dependent and it reproduces Planck's law in the time-periodic case, and thus fits with lots of experimental data. What more can you ask for?
SvaraRaderaI ask only that you present the analysis of the situation where there are two distant bodies A and B, say 1 light-day apart, where A begins as the warmer body and after a finite amount of time body B is rapdily heated to become the warmer body.
SvaraRaderaHow will the radiation from each of the two bodies behave as a function of time?
This is a simple idealized situation that any proposed law of heat and radiation must be able to handle, and the classical theory handles it easily by superposition of radation. It is also not identical to the setting which you have already analyzed and hence will provide a good test of you proposed physical laws.
I am not asking for the appearance of a second sun, only a verification of your law outside the exact situation where you claim to have derived it. One of the basic working principles in physics is that anything called a physical law should be applicable in a general situation, otherwise it is just a special case of some other law.
I do not see the scientific relevance of your example, but of course it is covered by the model. What do you want to know about what the model would tell?
SvaraRaderaThe scientific, in particular physical, relevance of the example is that it demonstrates how your model deals with the fact that information only travels with at most a finite speed, the speed of light in vacuum. This is not a problem for the classic model but it becomes non-trivial for a model like yours where the emitted radiation of a body depends on the temperature of other, distant, bodies.
SvaraRaderaIn particular this is part of determining if your model can deal with non-equilibrium situations, which are the most common ones in real life.
As before A and B are 1 light-day apart. Given that body A stays at a fixed temperature of say 100K and body B starts out at temperature 50K, and at time T=10, say, body B is rapidly internally heated to 200K and then stays at that temperature. What will the radiation sent out by A and B, individually, be as a function of time?
How is B rapidly heated? What is the shape of A and of B? What is the medium connecting A and B? Et cet...
SvaraRaderaLet's say that both bodies are perfect black spheres, both in perfect vaccum. All as simple as possible.
SvaraRaderaB could be heated by any internal heat source. Could be a battery and an electric element, or simple combustion.
Again, let us keep it simple. We could assume that B is heated at a linear rate for one second.
At first there will be net flow from A to B and after a day the net flow will change direction. The model describes each body as an absorber subject to forcing from the other and heating up only if the forcing comes from a body of higher temp.
SvaraRaderaOK?
Yes that is the effective picture you have given of your model, in words.
SvaraRaderaWhat I want to know is what each body radiates at a given time.
Will the body B start to radiate energy instantly as soon as it becomes the warmer body?
Will the body A continue to radiate heat until it has been reached by the information from body B?
If the answer to both questions is yes there will be a period of time when both bodies radiate, despite one being warmer than the other.
This will also mean that although there is only a net flow in the perfect equilibrium situation any local variation away from the equilibrium, and they do occur thanks to fluctuations, will lead to radiation being sent out by several bodies.
This would mean that the equilibrium picture with only one body radiating heat is unstable and fluctuations will lead to radiation coming from all bodies.
The exact dynamics you are after with the time delay in the electromagnetic contact between the bodies, is not obvious, but your example is far from realistic.
SvaraRaderaThe instant heating and finte speed of light are incompatible. With gradual heating the answer I gave is applicable.
The answer you gave is not applicable as soon as the distance between A and B is so long that it will take light longer to move between them than the time it takes to heat body B. This can easily be arranged by just making the initial distance between A and B long enough, taking whatever heating process we use for B into account.
SvaraRaderaThus the example is perfectly realistic. It could probably be performed within our solar system, where typical temperatures are much lower than the ones of A and B in the example.
However the behavior of a physical law should not depend on our ability to set up the particular experiment. I would also say that if a situation as simple as this one is too difficult to give a mathematical treatment of, rather than just a vague description in words, then the validity of the equilibrium picture that you have earlier proposed can not be taken for granted until a full mathematical analysis has been done.
The applicability to something as complex as the atmosphere seems far out of reach at the moment.
I agree that my model is simple and that is the beauty of it. You focus on an aspect of little interest. There are many questions of relevance which could be posed about the model. Why don't you pick one of those instead?
SvaraRadera"You focus on an aspect of little interest"
SvaraRaderaOn the contrary, whether a proposed physical theory behaves properly in connection with the finite speed of information transfer is a a fundamental question. A theory which does not agree with reality on this point would be immediately discarded by any physicist.
The property discussed here is the fact that the equilibrium picture you have given for your model seems unstable. In particular, the main point in you chosen application of the theory is that there should only be one body radiating heat and a unidirectional transfer of energy. In reality what seems to be the case is that in your model any fluctuation away from a perfectly uniform equilibrium will case all bodies to radiate energy, which in turn will mean that there is not a unidirectional energy flow even with this model
There is no model for two-way heat transfer, that I know of. Do you?
SvaraRaderaThe standard model for two way heat transfer in vacuum is so simple that it is an exercise in a beginners book on radiation and quantum mechanics.
SvaraRaderaBlack bodies radiate according to their temperature, this is not affected by other bodies and their temperature. Black bodies absorb incoming radiation, and are heated or cooled according to the difference between their radiated energy and the energy they have absorbed.
This is the simple consequence of Planck's Law together with the fact that, at normal energy levels, photons do not interact. Photon can interact but for anything except extreme gamma rays this is rare enough to be negligible.
If you have objections to this model, and my impression is that you do, then you will have to show that one of its components is incorrect.
The model of photon transport is either trivial ray tracing or non-trivial quantum electrodynamics, both models basically useless for radiative heat transport.
SvaraRaderaYes, photon transport at low energy in vacuum is essentially trivial, photons move in straight lines at constant speed, and photon-photon interactions at these energies are rare enough that we can ignore them. This also agrees with every experiment ever performed.
SvaraRaderaAt higher energies quantum electrodynamics must be used to analyze photon-photon interactions, but only at the energy levels seen in x-rays and gamma rays.
This model is not useless at all. It is simple, it is easy to compute with, it is internally consistent and it agrees with experiments.
It is obvious to anyone reading this blog that your theory does not hold together since you can never present precise answers to specific questions like "What is the temperature T_a(t) of body A as function of time t?" Your response is either to dismiss the question as not interesting, or your response is handwaving like "there will be net flow and then it will change direction".
SvaraRadera