Thanks for the post. Interesting reading. I found a counter point and the end will tell you why you won't find Miskolczi in any reputable cience journal.
http://www.drroyspencer.com/2010/08/comm...se-theory/
Radiative Exchange Equilibrium: A Consequence of Kirchoff’s Radiation Law?
Miskolczi makes the following statement regarding this supposed equality, which he calls “radiative exchange equilibrium”:
“for..two regions (or bodies) A and B, the rate of flow of radiation emitted by A and absorbed by B is equal to the rate of flow the other way, regardless of other forms of (energy) transport that may be occurring.”
This is the most surprising claim I have ever seen in this business, and I am quite certain it is false. (I’m not TOTALLY certain, because I could be dreaming right now, and you know how dreams can fool you).
He appears to attribute this to Kirchoff’s Law of Radiation (which he notes was actually discovered before Kirchoff).
But Kirchoff originally demonstrated his law with two plates in isolation, in a vacuum, with no other sources of energy from their surroundings.
Let’s look at how Kirchoff’s Law is stated by several different sources:
“At thermal equilibrium, the emissivity of a body (or surface) equals its absorptivity.”
“The ratio of emitted radiation to absorbed radiation is the same for all blackbodies at the same temperature.”
“The emissivity of a body is equal to its absorbance at the same temperature.”
“At equilibrium, the radiation emitted must equal the radiation absorbed.”
Note Miskolczi has done away with two caveats regarding his 2 bodies, A and B, that Kirchoff included: (1) energy equilibrium between two bodies, and (2) the bodies are isolated (no energy exchanges) from their environment. These conditions are not satisfied either at the Earth’s surface or in the atmosphere.
If Miskolczi is correct that the amount of thermal radiation emitted by an object (or layer of the atmosphere) ALWAYS equals the amount absorbed, this necessarily implies something that no one else I know of believes: that INFRARED RADIATIVE FLOWS BETWEEN IR ABSORBERS AND EMITTERS CANNOT CHANGE THEIR TEMPERATURE.
Let’s think about that. For IR energy flows to change the temperature of something, you need either a “convergence” of IR energy (absorption greater than emission) to cause the temperature to rise, or “divergence” of IR energy (emission greater than absorption) to cause temperature to fall.
But if the IR fluxes emitted and absorbed by an atmospheric layer are always the same, as Miskolczi claims, then the temperature of that layer cannot be changed through IR energy flows at all. Period.
And if THAT is true, then the greenhouse effect does not exist. Or, at a minimum, it is not caused by infrared radiation.
Another Thought Experiment
Obviously, if IR-absorbing layers A and B are identical in every way, including their temperatures, then the rate of IR flows between them will indeed be equal.
But let’s say layers A and B don’t touch (no conduction), and they do not interact with their surroundings. This would be like Kirchoff’s original experiment with the two plates.
Now, let’s take a blowtorch and heat layer A by 100 degrees. Layer A will now emit IR at a greater intensity than before, since its emission is proportional to the 4th power of its absolute temperature. Since the amount emitted is now greater that the rate of IR it is absorbing from layer B, layer A’s temperature will fall.
Meanwhile, over at layer B, since IR opacity is defined based upon the fraction of incident radiation it absorbs as that radiation is passing through, and layer A is now emitting IR at a greater rate than before (due to the blowtorch), Layer B now absorbs more than it is emitting.
This process – which Miskolczi claims does not exist – will eventually cause both layers to reach a new state of equilibrium, with equal temperatures, where both are emitting and absorbing IR energy at the same rate.
But Miskolczi’s theory says that the hotter layer will still emit radiation with the same intensity as it absorbs it. There would be no way for the hotter layer to transfer energy to the cooler layer. Presumably, the two layers’ temperatures would stay 100 deg. different.
Unless I am missing something important, this is a necessary consequence of Miskolczi’s claim. Maybe he thinks that since two atmospheric layers are already in a “quasi-steady state”, that their IR absorption equals their IR emission.
But this ignores other energy flows that we know are happening…most importantly, the convective transport of heat from the surface to the atmosphere. The surface is continuously dumping more energy into the atmosphere through convection. The atmosphere must emit more than it absorbs in order to cool itself.
The Hypothesis of a Constant Greenhouse Effect
Miskolczi additionally shows from 61 years of radiosonde data that a long-term decrease in the Earth’s greenhouse effect from humidity decreases in the middle and upper atmosphere have approximately counterbalanced the increase in the greenhouse effect from rising CO2 levels.
At face value, this might suggest that nature has mechanisms in place so that the total infrared opacity of the atmosphere remains about constant, consistent with the absorbed solar energy, and so the Earth’s temperature is naturally stabilized.
This might well be true.
But his conclusion from the radiosonde data depends upon the reality of relatively high humidity values in the very early years of radiosonde measurements, the 1950s and early 1960s. If you remove those years from his Fig. 9, then the drying trend that cancels the warming from increasing CO2 turns into a moistening trend.
Global “reanalysis” datasets extending back that far in time would have also the same problem, because those early radiosondes provide the most important source of information for the reanalysis.
Now, it might well be that nature has such a greenhouse effect-stabilizing mechanism in place, and that the total greenhouse effect stays at a relatively constant value for a given amount of absorbed solar energy. I have sometimes advanced the same possibility myself.
But I do not believe that Miskolczi has demonstrated either that it is the case, or why it should be the case.
In fact, the very nature of his claim that there are natural counterbalancing mechanisms at work keeping the greenhouse effect at a constant value implies that he thinks that the greenhouse effect DOES impact global average temperatures.
This seems to conflict with his claim that, by “law”, anything that absorbs IR at a certain rate must also emit IR at the same rate.
Since this law would remove the greenhouse effect entirely from the discussion of temperature change, why talk about compensating influences on the greenhouse effect? This does not make sense to me.
If Miskolczi is correct that the surface of the Earth does not lose any more IR energy than it gains from the overlying atmosphere, how is the surface cooled? Through 2 other mechanisms: (1) convective heat transfer from the surface to the atmosphere, and (2) loss of IR directly from the surface to outer space.
That convective heat transport is the dominant mechanism for moving heat from the surface to the atmosphere is not in dispute. I get angry e-mails from people who ask, “Why do you always talk about radiation? Convection is where it’s at!”
Yes, we all know that. For years I have talked and written about the cooling effects of weather are stronger than the warming effects of greenhouse gases. Lindzen in 1990 also emphasized this. We meteorologists were taught much more about convection than about solar and infrared radiation.
Even the (controversial and often maligned) K&T energy diagram shows the convective heat loss by the surface to the atmosphere (102 Watts per sq. meter) is about 4 times larger that the rate of IR loss by the surface to the atmosphere (26 Watts per sq. meter).
Thus, even in the “scientific consensus” view of global warming, convection is by far the primary mechanism by which the surface transfers heat to the atmosphere in the face of solar heating.
Yet, most of the computerized climate models still predict substantial global warming. So, obviously, they think a small change in radiation from more CO2 is pretty important.
IR Absorption and Emission Between Atmospheric Layers
So far, we have discussed the IR fluxes between the Earth’s surface and the atmosphere as a whole. What about the interaction between different layers in the atmosphere?
As I mentioned above, Miskolczi claims that the rates of IR exchange between atmospheric layers must be equal. He presents as evidence the fact that at any given level in the atmosphere, the rate of IR absorption by greenhouse gases is *nearly* the same as the rate of emission. This is shown in Fig. 3 of Miskolczi’s paper.
But the fact that these two flows are *nearly* the same is also consistent with standard greenhouse gas theory. It’s the tiny imbalance in them that makes all the difference. The greenhouse effect only becomes significant as we add up the cumulative effect of all the layers of the atmosphere.
Temperature changes have already minimized the imbalances between these IR flows, but a small imbalance still remains. This keeps the NET flow of IR energy through the climate system going “downhill”, from higher temperatures to lower temperatures.
To illustrate how tiny these IR imbalances in nature are, let’s examine what happens when we look at IR absorption and emission in 1 meter thick atmospheric layers, as Miskolczi presents in his Fig. 3.
The heat capacity of air is somewhat over 1,000 Joules per kilogram per degree C, which means it takes 1,000 Joules of energy to raise the temperature of 1 kilogram of air by 1 deg. C.
Conveniently, in the lower atmosphere 1 kg of air corresponds to about 1 cubic meter (1 m3) of air. So, for a 1 meter thick layer of air, 1,000 Watts per sq. meter (W m-2) heating applied for 1 sec would raise the temperature by 1 deg. C.
Or, since there are 86,000 seconds in a day, it would take (1000/86,000) = 0.01 Watts per sq. meter to get 1 deg. C per day warming rate.
Finally, if we double this, it takes about 0.02 Watts per sq. meter imbalance between IR absorption and emission to get 2 deg. C per day of temperature change, a very small number, indeed. And since the 1960s, investigators have been publishing atmospheric cooling rates of about 2 deg. C per day, which are caused by these tiny imbalances.
So, we see that it only takes a tiny imbalance between absorbed and emitted IR energy to accomplish realistic rates of cooling – or heating.
It’s the great depths over which these tiny numbers add up that matters. If we scale up to a layer 1,000 m thick in the lower atmosphere, then we need around 20 W/m2 more IR lost than gained by that layer for a cooling rate of 2 deg. C per day. (The required radiative flux imbalances go down dramatically with height, though, since air density drops rapidly with height…I have not added this effect in).
Once we reach the TOP of the atmosphere, the flow if IR from outer space into the atmosphere (essentially 0 Watts per sq. meter) is WAY out of balance with that upwelling from below: 235 Watts per sq. meter if you believe K&T; 250 Watts per sq. meter if you believe Miskolczi.
So, we see that for very thin layers of the atmosphere the IR emitted is very close to the IR absorbed. At the Earth’s surface, the flows exchanged between the surface and the atmosphere are very nearly equal. But not quite.
All of this has been known for a long time, and is totally consistent with greenhouse theory.
The Big Picture
With few exceptions, no two layers of the atmosphere ever reach a state of radiative equilibrium with one another, as Miskolczi claims. The same is true for the Earth’s surface and the overlying atmosphere as a whole.
All components are usually at different temperatures, with external sources of energy being absorbed, released, and flowing through them. As a result of these complexities, there is no requirement through Kirchoff’s Law that they emit and absorb radiation at the same rates.
Now, it IS true that those flows are “trying” to equalize, by exchanging IR energy in a direction that reduces temperature differences between layers. As a result, the differences in IR flows in opposite directions are indeed small – but they are not zero. Temperature changes have already relieved much of the imbalance.
Despite that fact that a major function of greenhouse gases is to provide a way for an atmosphere to cool to outer space, their presence at the same time warms the surface and lower atmosphere. While this seems counterintuitive, upon some reflection and thought we realize that this does make sense after all.
The currently ‘accepted’ theory suggests that adding more CO2 to the atmosphere has a small, but not totally negligible additional warming influence. Yes, the atmosphere is already mostly opaque at those IR wavelengths where CO2 absorption is significant. But not totally. Everyone knows that, including those scientists who work on climate models that produce catastrophic global warming.
The big question is, how much will that warming be? That’s where feedbacks come in…the warming magnification (positive feedback) or reduction (negative feedback) of the relatively weak CO2-induced warming by changes in clouds and other elements of the climate system. And that’s what I spend most of my research time on.
I have not yet seen any compelling evidence that there exists a major flaw in the theory explaining the basic operation of the Earth’s natural Greenhouse Effect.
I would love for there to be one. But I don’t see it yet.
And, again, if I have mangled what Miskolczi has said, I apologize. He is free to respond here if he wants to.
