Could ‘the greenhouse effect’ be one of those things that everybody claims to understand because it is apparently so important, but in reality it is not supported by a credible scientific literature?
That’s the view of Bill Kininmonth, meteorologist and head of Australia’s National Climate Centre from 1986 to 1998.
Furthermore, Mr Kininmonth is of the view that, “the role of greenhouse gases is to cool the atmosphere and this, with the surface warming from solar radiation, generates convective instability. It is the temperature lapse rate required for deep convection that leads to the ‘greenhouse effect’”
Confused?
Well in the following note, Mr Kininmonth explains in more detail:
The closest you will come to an explanation of carbon dioxide and the green house effect is in the ‘Frequently Asked Questions’ of the on-line IPCC Fourth Assessment Report.
My critique on them follows.
“The IPCC’s most recent assessment attempts to be helpful to the casual enquirer by having a series of explanations for ‘frequently asked questions’, or FAQs. The first FAQ is ‘What factors determine earth’s climate’? We are informed that, on average, the earth emits 240 w m-2 of radiation to space and that this equates to an emission temperature of -19oC. The earth’s temperature, however, is about 14oC and the -19oC temperature is found at a height of about 5 km above the surface. To quote the IPCC: “The reason the earth’s surface is this warm is the presence of greenhouse gases, which act as a partial blanket for the longwave radiation coming from the earth’s surface. This blanketing is known as the natural greenhouse effect”.
This explanation by the IPCC is clearly misleading, if not wrong. The inference that the greenhouse gases are acting like a blanket suggests that they are increasing the insulating properties of the atmosphere. However, the main gases of the atmosphere are oxygen and nitrogen, non-greenhouse gases, and they are also excellent insulators against the conduction of heat (like a blanket); adding additional trace amounts of carbon dioxide will have no appreciable impact on the insulating properties of the atmosphere.
In its third FAQ, ‘What is the greenhouse effect?’ the IPCC comes to the nub of the issue but provides a different and equally misleading explanation. “Much of the thermal radiation emitted by the land and the ocean is absorbed by the atmosphere, including clouds, and reradiated back to earth. This is called the greenhouse effect”. According to the IPCC’s global energy budget, the surface emits 390 W m-2 of radiation and the energy radiated back to the surface is 324 W m-2. It is difficult to see how an ongoing net loss of longwave radiation energy from the surface of 66 W m-2 can lead to warming! Indeed, we are all aware that between dusk and dawn the earth’s surface cools.
The IPCC has not explained in a scientifically sound and coherent way, how the ‘greenhouse effect’ is maintained. The greenhouse gases do not increase the insulating properties of the atmosphere and the back radiation does not warm the surface. The IPCC explanation of the greenhouse effect is obfuscation and, even to the mildly scientific literate, reflects ignorance of basic processes of the climate system.”
I am of the view that ‘the greenhouse effect’ is one of those things that is accepted because it is there, everybody claims to understand it because it is so important, but in reality few know how it comes about. My explanation follows (and you will not find this in IPCC publications):
“A credible explanation has no need for smoke and mirrors. The energy flow through the climate system is predominantly by way of four stages: 1) absorption of solar radiation at the surface; 2) conduction of heat and evaporation of latent energy from the surface to the atmospheric boundary layer; 3) convective overturning that distributes heat and latent energy through the troposphere; and 4) radiation of energy from the atmosphere to space. We will see that it is the characteristics of convective overturning that keep the surface warmer than it would otherwise be.
The Kiehl and Trenberth (1997) global average energy budget of the earth (see figure, where the units are W m-2) is used by the IPCC and is a useful starting point for explanation of the establishment and maintenance of the greenhouse effect.
Of the 340 units of solar radiation entering the earth’s atmosphere, 67 are absorbed by the atmosphere and 168 are absorbed at the surface. There is thus an ongoing source of solar energy available to the atmosphere and the surface.
At the surface there is a net accumulation of radiation energy because the incoming solar radiation (168 units) exceeds the net loss of longwave radiation (66 units).
In the atmospheric layer there is absorption of 417 units (390 of emission from the surface, less 40 that go directly to space, plus absorption of 67 of solar radiation) and an emission of 519 units (324 back to the surface and 195 direct emission to space). The net effect of the interaction between the greenhouse gases and radiation is a tendency to cool the atmosphere because it is continually losing energy.
Overall there is a dichotomy, with radiation processes firstly tending to warm the earth’s surface and secondly tending to cool the atmosphere. Air is an excellent insulator against conduction of heat and will not transfer heat through the atmosphere, as is necessary for energy balance. Also, the thermodynamic properties of air (potential temperature increases with height) ensure that turbulent motions of the atmosphere will mix energy downward, not upward as required.
The process for transferring energy from the surface to the atmosphere, necessary to achieve overall energy balance of the climate system, was explained by Herbert Riehl and Joanne Malkus (the latter better known as Joanne Simpson) in a 1958 paper, On the heat balance of the equatorial trough zone (Geophysica). Riehl and Malkus noted that boundary layer air, rising buoyantly in the protected updraughts of deep tropical convection clouds, converts heat and latent energy to potential energy. Away from the convection, compensating subsidence converts potential energy to heat.
What is implied in the Riehl and Malkus model is that deep tropical convection, and the transfer of energy from the surface to the atmosphere, will not take place without buoyant updraughts within deep convection clouds. That is, there is a need for the temperature of the atmosphere to decrease with altitude and that the rate of decrease of temperature must be sufficient to allow buoyancy of the air ascending in the updraughts. From well-known thermodynamic laws, the rate of decrease of temperature must be at least 6.5oC/km to allow the buoyancy forces of convection to overcome the natural stratification of the atmosphere.
The climate system will come into energy equilibrium when temperatures are such that the net solar radiation absorbed is balanced by the longwave radiation to space. At equilibrium, the greenhouse effect (ie, that the average surface temperature of 14oC is greater than the -19oC blackbody emission temperature of earth) is an outcome from the need for convective overturning of the atmosphere.”
Essentially, the role of greenhouse gases is to cool the atmosphere and this, with the surface warming from solar radiation, generates convective instability. It is the temperature lapse rate required for deep convection that leads to the ‘greenhouse effect’. But this takes the wind from the sails of the AGW folk.
William Kininmonth
Melbourne
Mr Kininmonth is the author of Climate Change: A Natural Hazard available from Amazons.
—————
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
“This explanation by the IPCC is clearly misleading, if not wrong. The inference that the greenhouse gases are acting like a blanket suggests that they are increasing the insulating properties of the atmosphere. However, the main gases of the atmosphere are oxygen and nitrogen, non-greenhouse gases, and they are also excellent insulators against the conduction of heat (like a blanket); adding additional trace amounts of carbon dioxide will have no appreciable impact on the insulating properties of the atmosphere.”
Didn’t we already go through this? It’s like a blanket, it’s also like a leaky bucket, and an atom is like a little ball. They are all metaphors to explain something that is very complex. Apparently Kininmonth is to stupid to realise that.
The greenhouse gases do not increase the insulating properties of the atmosphere and the back radiation does not warm the surface. The IPCC explanation of the greenhouse effect is obfuscation and, even to the mildly scientific literate, reflects ignorance of basic processes of the climate system.
Is that true or not? Does anyone know? If it is true it seems to stand the greenhouse issue on its head.
SJT
You have no science education by admission – so your post is typical lefty desperation – shoot the messenger! And all from the cowards’s castle of a pseudonym – you really are a second rate human being.
Louis,
Worse than second-rate, I’d say. Bill Kininmonth provides a well reasoned, logical critique, and what do we get from the gubmint science boys:
“Apparently Kininmonth is to [sic] stupid to realise that.”
That’s it? No rebuttal, no counter argument – nothing but “it’s all very complex” plus the obligatory insult.
Apparently the gubmint science boys think that is how you reason with people and persuade them as to the merit of your case.
One thing I do notice though – SJT has now progressed to outbursts comprising two or three phrases. If he continues to improve, he may yet make it up to second rate. With that, he could then be running the CSIRO.
Yes desperate times for leftwing idiots and still no hot spot plus no positive feedback to co2.
“leftwing idiots”
Tautology alert, Neville.
“…..radiation of energy from the atmosphere to space. We will see that it is the characteristics of convective overturning that keep the surface warmer than it would otherwise be……”
I think this is the absolute key point here. Think of an actual greenhouse. It hasn’t got a great deal to do with the greenhouse effect. Its all about the insulative property of air and about OVERTURNING (which I was calling TUNNELING-UNDER)
William I think is saying its overturning which is the most important reason for the reasonable temperature we have on earths surface.
If air is a great insulator its hard to see how he can be wrong about that. And everywhere we see that air is in fact a great insulator. The air trapped in your woollen jumper for example.
The troposphere is known for its up-down turbulence. If you look at the role of water vapour it will increase this overturning. Because water vapour is lighter than air. So pockets of air that have a great deal of water vapour in them will rise up quickly. Sometimes forcing warmer yet heavier air under. That is it will cause more overturning. Also the existence of clouds ought to cause more overturning as well . Since they would represent a strata of sorts.
Add to that the water vapour is carrying a lot of latent heat with it and its no sure thing where and how much the greenhouse effect is going to fit into the picture. They would fit the greenhouse effect in just to plug the gaps. Put plugging the gaps is always a presumptuous thing to do.
If we had never learned about this greenhouse effect we’d have a lot better models of the situation that focused more on overturning and other matters currently being neglected.
SJT’s comment above beggars belief.
AGW proponents believe that the earth’s atmosphere is stratifed according to chemical composition – a “blanket of GH gases” enveloping it.
What utter nonsense.
Gases do not stratify – they, because being gases and from Brownian motion – mix to produce one gas with a specific chemical composition that is dependent on the relative proportions of the individual gases making the final mix.
There is no physical structure to a gas – it is matter excited to a state in which random molecular motion dominates.
To propose that this structureless matter is capable of being partitioned into discrete physical phases is an admission of crass ignorance of science.
It might well be described as Nu-Science.
SJT
I hate say this, but you are becoming a bit of a nuisance here.
Your constant derisory comments distract from the forum.
I am no scientist either, that’s why I try to read the posts of those with more knowledge, so I can gain an understanding.
William Kininmonth: “the back radiation does not warm the surface”
RA: “Is that true or not?”
The statement sounds odd to me. I would have thought that the difference between thermal equilibrium at one temperature, and thermal equilibrium at a higher temperature, is that the flux of energy is greater at the higher temperature. Energy in still equals energy out, but it’s flowing more rapidly or in greater quantity. So if the atmospheric back radiation were to disappear (see the diagram accompanying the post), there would be less outgoing thermal flux from the ground, and consequently the ground would be cooler. Therefore there is a sense in which the back radiation warms the ground.
For blackbodies there is definitely a law relating radiant flux and temperature, but I’m not sure how best to think about the more complicated situation here.
“I am no scientist either, that’s why I try to read the posts of those with more knowledge, so I can gain an understanding.”
You won’t learn much from such posts as Kininmonth is making. Why doesn’t he say it’s not like a blanket because he can’t see a big, thick, wooly thing up in the sky. His argument is sheer ignorance. It’s like a blanket because a greenhouse gas effectively slows down the transfer of radiation to space, causing the earth to warm.
Mitchell
I would have thought that “thermal equilibrium”
is just that, no matter what the temperature.
Therefore the argument he posited stands.
The rest of it, I cannot argue, not having enough knowledge.
If greenhouse gases have a net cooling effect, why don’t we freeze solid every night?
By the way, I’ve just noticed that the version of this article which Jennifer posted four days ago–
http://www.jennifermarohasy.com/blog/archives/003327.html
–also has an alternative (non-IPCC) calculation of the strength of the anthropogenic or enhanced greenhouse effect, missing from this version. The extra feature this version has (apart from the conference invite at the bottom) is the illustration of the energy flows.
AB
The presence of water stops that. We are, more or less, comprised of water.
SJT
“It’s like a blanket because a greenhouse gas effectively slows down the transfer of radiation to space, causing the earth to warm.”
Any refereed papers supporting this statement?
“Back radiation does not warm the surface”.
This is the same as stating that if you stood in front of a fireplace, became warmed and emitted IR radiation, that you would therefore increase the temperature of the fire.
No.
But this happens in NU-Science.
“But this happens in NU-Science.”
It also happens in IPCC applied science..
http://www.ilovemycarbondioxide.com/ipcc_oven.html
I find the argument really convincing. Although I don’t see that some sort of greenhouse effect is ruled out in its entirety. Mitchell Porters comment is about where I’m at with it.
In Williams essay is he ruling out some sort of greenhouse effect in its entirety or merely drastically reducing its important?
It had been my position that the importance generally ascribed to the greenhouse effect, and particularly the allegation that it was about 30 degrees, was a ridiculous over-emphasis, since there were other factors involved.
But is William saying that there is no effect at all? And if so is the reasoning for this contained entirely within the above essay or is there more to it?
My position had been partly that the alarmists were pyramiding an exaggeration, on an ambit claim on an over-emphasis. That they were doing this in a systematic way.
So they over-emphasise the total role of greenhouse, then the relative role of CO2, then the amount of the extra-CO2 due to human causes, then the amount of the effect of the extra-CO2 versus the CO2 that was already there.
I don’t want to be an extremist about it. And because I don’t quite understand all of Williams argument yet agree that the overturning business must be massively important, I cannot really come good with ruling out some sort of importance of greenhouse. But is William ruling out a greenhouse (a gas-colour) contribution outright?
“This is the same as stating that if you stood in front of a fireplace, became warmed and emitted IR radiation, that you would therefore increase the temperature of the fire.”
Thats a great analogy Louis. I’m going to steal it and run like a thief in the night.
Ironically for the preceding discussion about back radiation, Kininmonth says in the longer version of this article posted on Wednesday: “An increase in back radiation adds energy to the surface, which will further warm the surface.” So some of that discussion is just semantics. Back radiation warms the ground in that it delivers energy to it; radiative interaction with the atmosphere cools the ground, in that more is lost than is gained; and an increase in back radiation will warm the ground, in the sense of inducing a higher temperature.
“This is the same as stating that if you stood in front of a fireplace, became warmed and emitted IR radiation, that you would therefore increase the temperature of the fire.”
Still don’t get it, do you? Another case of, “If I can’t understand it, you can’t prove it”.
Louis Hissink: “This is the same as stating that if you stood in front of a fireplace, became warmed and emitted IR radiation, that you would therefore increase the temperature of the fire.”
That’s right.
Of course, when you turn the fire off the fireplace will cool rapidly, and if you continue to sit in front of the fireplace then the heat radiated from you would slow down the cooling of the fireplace – once its temperature drops below your temperature.
Analogous to this, after sunset the surface starts cooling, and when it drops below the temperature of the air then back-radiation slows down the surface cooling. But, given the huge difference in thermal capacity between the surface and the air, this effect is really negligible.
SJT: “Still don’t get it, do you? Another case of, “If I can’t understand it, you can’t prove it”.”
How about explaining it to us in terms which us morons can understand then!
You’ll have to type slowly though, because we can’t read fast.
Global Warming due to carbon dioxide simply does not happen; it has not been observed. Carbon dioxide goes up, but global temperature does not.
(If you believe otherwise, the burden of proof is yours, and good luck).
Arguing the details of how exactly it does not happen could be fun, though. Such discussion may someday become productive scientificly; but for humanity today provide a distraction from the more serious, historicallyt sinister, but unmentioned, factors in climate. A scientific Dumb is Happy situation.
“Analogous to this, after sunset the surface starts cooling, and when it drops below the temperature of the air then back-radiation slows down the surface cooling. But, given the huge difference in thermal capacity between the surface and the air, this effect is really negligible.”
Right. One thinks of all sorts of things once you add back reality. AGW models do not appear to such much as take into account the reality of night and day.
The stupidity of these people not adding back more reality to their models once they have clearly failed empirically is just depressing.
I must confess to a certain amount of frustration reading this article: the fellow can’t do sums! He scatters numbers about willy-nilly without any justification. I urge everybody to just look at the diagram he presents; it shows where the power is coming and going. Start with the top. He shows 342 W m**-2 coming in, and 107 Wm**-2 plus 235 Wm**-2 going out: 342 Wm**-2. The incoming and the outgoing are equal to each other.
Now follow the flows lower down. They get complicated because they’re broken up across multiple layers, but in the end, all the sums add up properly.
But Mr. Kininmonth can’t add up the numbers properly:
” It is difficult to see how an ongoing net loss of longwave radiation energy from the surface of 66 W m-2 can lead to warming!”
Mr. Kininmonth is leaving out all but two parts of the diagram.
C’mon, folks, you can’t really fall for such a stupid mistake! Go through the diagram piece by piece and you’ll see, the numbers really do add up.
You moron Crawford. Is THAT all you are taking from the above? What about the important point of OVERTURNING. The role of standard air in heat retention. If you are going to be that blinkered Deltoid is the place for you. Deltoid is the home of mindless bigots.
Kininmonth’s lengthy discussion might sound “scientific,” but look closely. He is upholding the Kiehl-Trenberth model, the very model the IPCC refers to.
http://ipcc-wg1.ucar.edu/wg1/FAQ/wg1_faq-1.1.html
No matter how you frame it, 102 watts per square meter go up from the surface and 324 W/m² come raining down. Added to the remaining surface energy, 66 W/m², this 324 manufactures the requisite 390 W/m² modelers have to aim at, since it corresponds to 14.8 C, regarded as the earth’s average temperature. Yet the atmosphere has acquired 169 W/m² at most. Where did an extra 155 watts per square meter come from?
Notice too that this energy is asymmetrically radiated in two directions, 165 outward and 324 downward. Thus this hovering gaseous body has a radiative strength of at least 489 W/m². This is another bizarre greenhouse theorem, that an atmospheric layer has two sides and so can radiate 1 watt of received energy as 2 watts. Or more energy if it likes and in any way it likes.
http://www.ilovemycarbondioxide.com/FAQ.html
“The factor of two for A (the radiation emitted from the atmosphere) comes in because the atmosphere radiates both up and down.” — NASA’s Gavin Schmidt
http://www.realclimate.org/index.php/archives/2007/04/learning-from-a-simple-model/
Notice also that a satellite will only observe the earth emitting 235 W/m². Most of the 390 from the surface is never seen because it is never radiated.
In other places Kininmonth makes the claim that, “Greenhouse gases emit more radiation than they absorb”. That’s a quote, folks. What’s more, this greater-than-possible radiative efficiency is a COOLING mechanism in his view, counteracted by greenhouse gases radiating LESS than they absorb elsewhere, which is how the earth’s surface is HEATED… ???
Look again at the Kininmonth/IPCC/Kiehl-Trenberth illustration. Do you see greenhouse gases radiating less than they absorb as they heat the surface? (For an analog of people not seeing what’s right in front of them, read the story of The Emperor’s New Clothes.)
Both conductively and radiatively, hot moves to cold. Energy transfers from a higher energy zone to a lower energy zone, like water running downhill. Although people typically misplace this fundamental point, it is the second law of thermodynamics and any model of heat-transfer must conform to it. Models of radiative exchange in the earth’s atmosphere have passed the point of incoherence. Kininmonth’s is no different.
Alan, where do you get the figure “102 watts per square meter go up from the surface”? Is this radiative energy? convection? Evaporative transpiration? What do you mean by that number?
Also, when you write, “324 W/m² come raining down” am I correct in assuming that you are referring ONLY to the back radiation from the atmosphere?
Next you write ” Added to the remaining surface energy, 66 W/m²” Where does that number come from? And it can’t be energy, because we’re talking about power per unit area, not energy.
You write, “his 324 manufactures the requisite 390 W/m² modelers have to aim at, since it corresponds to 14.8 C, regarded as the earth’s average temperature.”
Modelers don’t have to aim at that number, because they don’t use that number. This is a first-order calculation, meant to teach the basic physics to beginners; what models actually use is vastly more complicated than this.
You write, “Yet the atmosphere has acquired 169 W/m² at most.” Again, where does this number come from? And what do you mean by “acquired”? Your terminology here is so vague that it’s impossible to figure out precisely what you mean.
“Notice too that this energy is asymmetrically radiated in two directions, 165 outward and 324 downward.”
No, it’s symmetric; you’re just leaving out some of the pieces of the formula. Look again at the diagram and look at ALL the sources of power going into the atmosphere:
67 Wm**-2 absorbed
24 Wm**-2 convection
78 Wm**-2 evaporative transpiration
350 Wm**-2 surface radiation
That adds up to 519 Wm**-2 of input power. Now look at the output power:
165 Wm**-2 emitted upwards
30 Wm**-2 emitted upwards by clouds
324 Wm**-2 emitted downwards to the surface
Guess what: that adds up to 519 Wm**-2 — exactly the same amount going in! This is what we mean by equilibrium. The sums really do add up; you just have to include ALL the factors.
“Energy transfers from a higher energy zone to a lower energy zone, like water running downhill. ”
Not quite. Again, you’re using informal terminology. Energy is transferred from a higher temperature reservoir to a lower temperature reservoir in direct proportion to the difference in temperature and inverse proportion to the thermal resistance between the two reservoirs.
“Although people typically misplace this fundamental point, it is the second law of thermodynamics”
No, it is most definitely not an expression of 2nd Thermo, which says that the entropy of an isolated system will never decrease.
“This is the same as stating that if you stood in front of a fireplace, became warmed and emitted IR radiation, that you would therefore increase the temperature of the fire.”
That’s correct, Louis. But this is the cornerstone of greenhouse theory: “back-radiation.” And this absurdity is shared by Vincent Gray, Roy Spencer, Barry Hearn (editor of JunkScience) and many other so-called skeptics, probably most. Classical physics states that thermal energy travels just one way, from a higher energy body to a lower energy body. Greenhouse physics states that thermal energy travels two ways, from a higher energy body to a lower energy body and from a lower energy body to a higher energy body. It never occurs to greenhouse believers that this entails the progressive warming of both bodies, an infinitely expanding heat-cycle.
William or cohenite (whatever) – “However, the main gases of the atmosphere are oxygen and nitrogen, non-greenhouse gases, and they are also excellent insulators against the conduction of heat (like a blanket); adding additional trace amounts of carbon dioxide will have no appreciable impact on the insulating properties of the atmosphere.”
However you left out of this ‘discussion’ water vapour. On out watery planet there is a significant amount of it in the atmosphere. Are you trying to say that if there was not water vapour in the atmosphere the Earth would still be 33deg above blackbody?
“Overall there is a dichotomy, with radiation processes firstly tending to warm the earth’s surface and secondly tending to cool the atmosphere.”
Cool the STRATOSPHERE not the atmosphere. I think that you are forgetting that the atmosphere has several distinct layers with quite different properties. The circulation only takes place in the troposphere where water vapour dominates. Higher up the air is much dryer.
I look forward the to paper you are writing explaining this. E&E have not published much lately. You model runs without greenhouse gases should be illuminating.
“Alan, where do you get the figure ‘102 watts per square meter go up from the surface’?”
Sorry, Chris, but by this time you’ve pretty much proved yourself an idiot on all counts. If you haven’t noticed, the Kiehl-Trenberth energy budget is expressed in watts per square meter throughout. Via direct absorption of solar energy, the atmosphere acquires a radiant strength (“wave density”) of 67 W/m². Via transfer of surface energy to the air, it acquires another 102 W/m². Can you follow the arrows? From there, without the magical effect of “greenhouse gases,” the atmosphere would radiate 169 W/m² to space and the surface would radiate the remainder, 66. Can you add 169 and 66? That’s right, the sum is 235, the same as the sun’s input. Lucky for us, however, 1% of the atmosphere’s contents allow the system to generate 390 W/m² — 155 W/m² of which are never radiated to space. Ain’t that remarkable?
The second law of thermodynamics constrains the direction of heat transfer. This direction is from greater temperature to lesser unless an outside force is applied. Anyone who’s absorbed physics lessons beyond rote verbalization understands this.
By the way, you’re confusing an isolated system with a closed system. In a closed system the components exchange energy but not mass. As a conceptual category only, a matter of schematic convenience, the sun earth-space relationship is treated as a closed system. Peddle your wares on someone else.
“Guess what: that adds up to 519 Wm**-2 — exactly the same amount going in!”
I rest my case.
Alan, you quote Louis and respond as follows:
““This is the same as stating that if you stood in front of a fireplace, became warmed and emitted IR radiation, that you would therefore increase the temperature of the fire.”
That’s correct, Louis. But this is the cornerstone of greenhouse theory: “back-radiation.” ”
Actually, the walls of a furnace DO re-radiate energy back to the fire and they DO increase its temperature. Indeed, the concept of the furnace walls reflecting heat is the basis of the ‘reverberatory furnace’, an important technological development in metallurgy.
You write: ” Classical physics states that thermal energy travels just one way, from a higher energy body to a lower energy body.”
Yes, but that applies to the NET energy, not all the energy. Radiant energy — light — can be reflected. If you put a mirror in front of a fire, does NONE of the firelight get reflected back to the fire? Radiant energy can also be absorbed and re-emitted. If you put a poker near but not inside a roaring fire, does not the poker glow red-hot? It’s emitting light. Are you saying that this emitted light is free to travel in all directions, but is somehow barred from traveling toward the fire?
You write: ” It never occurs to greenhouse believers that this entails the progressive warming of both bodies, an infinitely expanding heat-cycle.”
No, you misunderstand the process. The fire emits, say, 1000 watts of power. Let’s say that 10 watts of that power strike the poker, heating it until it reaches thermal equilibrium and is emitting 10 watts of power. A small part of that 10 watts — say 0.1 watt — will hit the fire, causing it to heat up ever so slightly, so that it emits 1000.1 watts of power. So now the poker is receiving 10.001 watts of power — this is an infinite series that converges to a finite value. It doesn’t go infinite.
Alan, once again you are using weird terminology that doesn’t make sense. What is “radiant strength”? And what is “wave density”? You’re slinging around a bunch of terms that have no meaning.
I think I can guess what you’re driving at. If you consult the diagram, it shows 24 Wm**-2 labeled as “thermals” (‘convection’ is the better term here). It also shows 78 Wm**-2 labeled “evapo-transpiration”. I note that 24+78 = 102. So perhaps you were referring to the sum of these two factors when you wrote ‘102 watts per square meter go up from the surface’. You should have written something like “convection and transpiration transfer 102 Wm**-2 from the surface to the atmosphere.” Then I would have understood you.
OK, so you’ve got the 67 Wm**-2 that is directly absorbed by the atmosphere plus the 102 Wm**-2 that is transferred by convection and transpiration. That adds up to 169 Wm**-2. But then you go off the rails with your statement that “the surface would radiate the remainder, 66”. Look again at the diagram: it clearly shows that the surface directly radiates 40 Wm**-2 into space, not the 66 Wm**-2 that you pulled out of a hat. It’s that little gray channel running from the surface, in front of the cloud, and merging with the other radiation heading out to space. It’s marked “40” in two places, one of which is also labeled “Atmospheric Window”.
Where your numbers really depart from anything previous is this statement: “Lucky for us, however, 1% of the atmosphere’s contents allow the system to generate 390 W/m² — 155 W/m² of which are never radiated to space.”
What does that mean? By “atmosphere’s contents” do you mean all the gases in the atmosphere, or are you referring to some portion of the atmosphere. And WHICH 1% of these “atmospheric contents” is generating? Please be precise! And how do the atmospheric contents “allow” the system to generate power? Do they themselves generate the power or are they merely giving some other element permission to generate power? And what is “the system”? Are you referring to the entire planet? And where did you get the value 390 Wm**-2? And if 155 Wm**-2 never radiates into space, where does it go? Does it remain on earth? If so, does it show up as heat?
You write “you’re confusing an isolated system with a closed system.” You then proceed to define a closed system. So tell me, what’s the difference between an isolated system and a closed system? I’ve seen those two terms used interchangeably in thermodynamics.
Furthermore, your definition of a closed system (“In a closed system the components exchange energy but not mass.”) does not describe anything I have ever studied. The concept of closure (or isolation) refers to the system as a whole, not its components. And neither the sun nor the earth nor the combination of the two is a closed system — they’re both radiating vast amounts of energy into space!
Lastly, from the tone of your comments I infer that you are growing rather testy. I plead with you to cool down and discuss this calmly.
“We were told there wouldn’t be any math.” said the bubbleheaded hotel heiress, Los Angeles Laker fans, and the collected climate change lobbiest.
ender bender; now you’re verballing me even when I haven’t posted; now, MR TOA, polly wants a peer-reviewed paper, let me ask you and your suave mate, Chris, this; nitrogen and oxygen constitute over 99% of the atmosphere; are you telling everyone that those gases do not play any part in heat regulation of the atmosphere and surface; and I might add, when considering that, that you should ignore the fact that nitrogen and oxygen do have some radiative absorption capacity, however relatively slight; simply consider conductive interaction with the surface warmed by incoming solar radiation and convective transfer.
Secondly, do you both assert that IPCC is capable of making long-term prediction of future climate states given that the climate system is a coupled non-linear chaotic system; and if it isn’t what right does it have to promulgate AGW to great upheavel and disruption; here’s a reference to assist you in the second question;
http://www.grida.no/CLIMATE/IPCC_TAR/WG1/501.htm
“Furthermore, your definition of a closed system does not describe anything I have ever studied.”
That may be half the problem. Anyone can look up what closed, open, and isolated systems refer to in thermodynamics. We two aren’t talking on a desert island where books and other information sources are unavailable, after all. So who are you kidding? It sure isn’t me. My reaction to your persistent irrelevance (e.g., what the second law states or what the value 390 W/m² refers to) is entirely appropriate. Grow up.
By the way, in a reverberatory furnace the contents get heated to some extent by radiance from the walls instead of directly from the flame itself, which is the thing to be avoided. The fire’s intensity isn’t amplified by its own radiation. Who the hell is telling you these things?
“Guess what: that adds up to 519 Wm**-2 — exactly the same amount going in!”
A classic.
Alan, if the definitions of closed, open, and isolated systems are so easy to find, then I suggest that you present some. My own understanding is that a closed system is the same as an isolated system: there is no thermal exchange with anything outside of the system. If you have a better definition, please present it. The definition you provided is quite strange; have you a source for it?
And yes, the reverberatory furnace demonstrates quite clearly that objects adjacent to a heat source can transmit heat energy.
Again, I implore you to calm down and discuss these issues with me calmly.
cohenite – “ender bender; now you’re verballing me even when I haven’t posted;”
As Mr Kininmonth’s ideas coincide with the sort of rubbish that you have been posting I did have a thought that cohenite was Mr Kinninmonth’s pseudonym.
“are you telling everyone that those gases do not play any part in heat regulation of the atmosphere and surface;”
No I am not saying it. Air does insulate however static air insulates not moving air such as in the troposphere. For instance foam insulators insulate because they trap bubbles of air and immobilise them reducing the convection of heat. The foam and air are both poor conductors of heat so both these things also reduce the heat flow. Add a layer of silver material and you reduce the flow even more by blocking radiation.
http://www.ornl.gov/sci/roofs+walls/insulation/ins_01.html
“Batts, blankets, loose fill, and low-density foams all work by limiting air movement. (These products may be more familiarly called fiberglass, cellulose, polyicynene, and expanded polystyrene.) The still air is an effective insulator because it eliminates convection and has low conduction. Some foams, such as polyisocyanurate, polyurethane, and extruded polystyrene, are filled with special gases that provide additional resistance to heat flow.
Reflective insulation works by reducing the amount of energy that travels in the form of radiation. Some forms of reflective insulation also divide a space up into small regions to reduce air movement, or convection, but not to the same extent as batts, blankets, loose-fill, and foam. ”
As the troposphere is in an almost constant state of movement it is not an effective insulator certainly not enough to account for radiant energy budget of the Earth. The only thing with the required magnitude is the main greenhouse gases water vapour, CO2 and methane. Of those water vapour is a feedback and CO2 has the most potential for growth. Methane is sort of under control.
Cohenite: To proceed further into forbidden territory, may I suggest that the insulative effect of other gases is a non-issue? Yes, air is definitely a good insulator. But why? Because it mimics a vacuum. Compared to a dense medium like water or metal, air absorbs heat poorly. Which means that a warm body immersed in air suffers less conductive (and consequent convective) loss, leaving radiation as its relatively greater means of dissipating heat. I stress the word ‘relatively’ because note: air does not ENHANCE radiative emission; it only limits the other two heat-loss mechanisms. And a vacuum does this even better.
Contrary to science-fiction fables, the vacuum of space isn’t cold — it simply has no temperature. Indeed, because a vacuum provides no conductive or convective avenues, getting RID of heat is a spacecraft’s principal problem. To make a spacecraft habitable, one is forced to transport cabin heat into massive panels that are kept askance from the sun’s rays. Heat is pumped into and distributed over their surface area and this gets radiated into space because the cabin is unable to do that job alone.
But, immersed in a vacuum, the earth itself is such a spacecraft. Surface heat to the air is only one step in the process of heat-transfer. The next is radiating this thermal energy to space — which, as it turns out, is comparatively inefficient. I ask you to consider, then, that in this respect the insulative property of air isn’t germane because “greenhouse gases,” as thermal energy absorber/emitters, don’t insulate the earth in the first place. They are thermal conveyers, not insulators. By contrast, the earth is surrounded by the least conductive “medium” known.
Alan, most of your comment is correct, but in the last paragraph, there are two minor errors. It isn’t quite correct to state that greenhouse gases are not insulators. (I assume we’re talking only about radiative transfer, because if we weren’t, it would be easy to show that GHGs can transfer heat convectively).
If you think of radiative transfer in terms similar to electrical current flow, then you can use the concept of electrical resistance to get a firmer grip on the problem. Just use Ohm’s Law, with temperature corresponding to voltage, heat flow corresponding to current, and thermal insulation corresponding to resistance. Thinking this way, the action of the greenhouse gas acts like a resistance, reducing heat flow, causing the temperature to rise until the delta-T is large enough to push enough heat flow through the resistance.
However, if you’re not familiar with Ohm’s Law, then this analogy will only add to the confusion.
Finally, when you write, “By contrast, the earth is surrounded by the least conductive “medium” known”, that’s true for convection and conduction of heat, but not for radiation. A vacuum is a perfect transmitter of radiation — it absorbs nothing.
“By contrast, the earth is surrounded by the least conductive “medium” known.”
What the devil does conductivity have to do with radiation you gerbil?
Speed of light in a vacuum: 299,792,458 meters per second
Speed of light in air: 298,925,574 meters per second
Some resistance. Some reduction of current.
Since passage through a refracting medium is the only thing that reduces the speed of light, you’re implicitly claiming that refraction equals heating. Yet light’s energy remains unchanged as it passes from one refracting medium to another. One can think of refractive slowdown as the difference between water flowing thru a fire hose (vacuum speed) and water being passed along in a bucket brigade (from atom to atom). The same amount of energy is transmitted but by a different means. And infrared moves at the speed of light. “Slowly moving” infrared is yet another greenhouse myth.
Back to the drawing board for you.
To the other gerbil: I am saying that if space were “cold” as we commonly think of cold, there would definitely be a need to insulate the earth from such an infinitely large body continuously robbing it of heat. But the earth is not surrounded by a cold body; it is surrounded by no body, quite an exotic concept to comprehend. Raising the subject of insulation is therefore incongruous to the context. It’s like wanting to know what invisibility looks like.
Alan: “By the way, you’re confusing an isolated system with a closed system.”
don’t be too hard on him I’ve seen people with strings of letters behind their name suggesting they should know better confuse that one.
Alan writes: “What the devil does conductivity have to do with radiation you gerbil?”
Well… [nibble, nibble, nibble]… you have been misusing the terms for so long I didn’t take you seriously when you actually got one right… [nibble, nibble, nibble]… so I wanted to make certain that you understood that your comment was confined to thermal conductivity… [nibble, nibble, nibble]… say, are you going to eat that sunflower seed? 😉
However, you get it badly wrong when you use the difference in the speed of light in a vacuum and the speed of light in air to infer that the air provides resistance to the passage of light. The lower velocity of light in air is due to the dielectric properties of air. Light passing through air does not lose any energy whatsoever due to those dielectric properties. It does suffer some collisions between some photons and molecules in the air, but these don’t slow down the other photons. The photons that don’t collide with air molecules lose no energy in passing through the air. Therefore, there is no resistance in the sense used in Ohm’s Law. And in fact, you assert precisely this point in the following paragraph — which leads me to wonder which of the two contradictory points you really adhere to. And no, I’m not claiming that refraction generates heat — that’s YOUR inference, not mine.
Your analogy to a fire hose versus a bucket brigade is way wrong: light traveling through a refractive medium moves in exactly the same fashion that it moves in a vacuum, but because the local dielectric constant is different, it moves more slowly.
You write: ““Slowly moving” infrared is yet another greenhouse myth.”
Wow! Where’d you see that one? I agree, the notion of infrared light moving more slowly than other forms of EM is absurd. But I certainly didn’t say it, so why are you raising it with me?
“light traveling through a refractive medium moves in exactly the same fashion that it moves in a vacuum”
No, a sequence of excitation and emission occurs in a refractive medium. No such chaining occurs in a vacuum, where light travels fastest.
You’re an embarrassment. You can’t even get two gerbils right, let alone recall that you brought up the electrical resistance analogy. Seek help.
Alan; thanks for some interesting insights; I’ll have to rethink the nitrogen/oxygen imput; the issue of atmospheric pressure remains unresolved though; thinking of your light in a box thought idea got me thinking of the geodesic domes and the life-dome concept which flowed from that; here is an interesting take on that which seems to dovetail with the aspects of this discussion;
http://www3.interscience.wiley.com/journal/118570340/abstract
I also seem to recall a horror story whereby a man was locked in a box with mirrored walls with a light source, and either went mad or froze or boiled; maybe we could call for volunteers; speaking of ender bender and Chris; you both continue to ignore the central issue of the Pielke paper, which ender bender dismisses as whinging rubbish; this issue is; does an IR photon leaving the atmosphere at the poles have as much temperature consequence as a photon leaving at the equator; conversely, does a photon prevented from leaving at the poles have the same impact on temperature as a photon stopped from leaving at the equator? The Pielke paper again;
http://climatesci.colorado.edu/publications/pdf/R-321.pdf
“Alan; thanks for some interesting insights;”
Haven’t you heard, Alan is the token Socratic Ironist. He is here purely for the purpose providing some ignorance for the forum.
cohenite – “does an IR photon leaving the atmosphere at the poles have as much temperature consequence as a photon leaving at the equator; conversely, does a photon prevented from leaving at the poles have the same impact on temperature as a photon stopped from leaving at the equator? The Pielke paper again;”
I assume this is the part that you are talking about which is simple a rehash of what Motl was going on about.
“At its most tightly coupled, T is the radiative temperature of the Earth, in the sense that a portion of the radiation emitted at the top of the atmosphere originates at the Earth’s surface. However, the outgoing longwave radiation is proportional to T4. A 1C increase in the polar latitudes int the winter, for example, would have much less of an effect on the change of longwave emission than a 1C increase in the tropics.”
And the answer is yes I guess it would in the crude first order calculations that are done at the start of the investigation where a global average temperature is used along with a global average albedo and a global average emissivity.
However as both Chris and I have patiently tried to explain to you that these first order calculations are not the be all and end all of climate models. More sophisticated calculations that take into account regional differences. Pielke of all people knows this so why this is in the paper I do not know.
The polar regions with their high albedo reflect the SW radiation right back out again without absorption so if you want more accurate figures you have to take into account regional differences which more sophisticated models do.
Those “regional differences” and “sophisticated models” would be the ones Koutsoyiannis looked at I suppose?
This was a most interesting series of comments, the strange part about it is that there are elements of truth in a lot of the opposing views but an incredible amount of confusion and lack of understanding of the different mechanisms for the energy transfer within the atmosphere. The “greenhouse gas effect” basically only occurs in the long wave IR absorbing molecules #1 water vapour #2 CO2 ( methane, ozone, nitrous oxide, all insignificant)All these molecules absorb only specific radiation frequencies which are in their resonant frequency bands, in the case of CO2 only 8% of the outgoing IR spectrum will be absorbed. The molecule gains energy but transfers it by colliding with other molecules thus there is some heat extracted from the outgoing radiation and converted into an increased temperature of the gasses in the atmosphere. However once the frequencies have been removed they do not magically reappear so the CO2 at higher levels have nothing to work with. There is a little reradiation back to the surface from the energized CO2 molecules but this occurs only in the first 2 or 3 meters of atmosphere and is minor. Water vapour reactes in a similar manner but absorbes more energy than CO2 because it has more resonant frequency bands closer to the peak of the spectrum. The total greenhouse gas effect of CO2 is estimated to be 3 deg C which occurs in the first 50 meters of atmosphere by the 8% energy extracted and once removed from the spectrum there is no longer any energy left so increasing the CO2 has no effect. Now the big guy on the block is water droplets or aerosol. Aersols which include smoke, volcanic ash, fly ash etc. behave entirely differently, they will absorb the entire spectrum and reradiate the entire spectrum just like any black body thus they do behave like a blanket, the gasses because they are frequency specific do not.As has been said the other massive factor in the energy balance is the convective behaviour in the atmosphere. When air rises it expands and cools down by JT effect when it decends it is compressed and therefore heats up. It short the very large majority of backradiation comes from aerosols and very little comes from greenhouse gas molecules. One last thought there is a lot of energy transfer within the atmosphere but it must be remembered that when one atom or aerosol looses energy its temperature drops and the recipient of that energy will have a temperature rise so the net effect is zero, the only thing that effects the temperature of the earth is the transfer of energy between the surface and the atmosphere and in this regard I believe the convective heat removal is underestimated.
This was a most interesting series of comments, the strange part about it is that there are elements of truth in a lot of the opposing views but an incredible amount of confusion and lack of understanding of the different mechanisms for the energy transfer within the atmosphere. The “greenhouse gas effect” basically only occurs in the long wave IR absorbing molecules #1 water vapour #2 CO2 ( methane, ozone, nitrous oxide, all insignificant)All these molecules absorb only specific radiation frequencies which are in their resonant frequency bands, in the case of CO2 only 8% of the outgoing IR spectrum will be absorbed. The molecule gains energy but transfers it by colliding with other molecules thus there is some heat extracted from the outgoing radiation and converted into an increased temperature of the gasses in the atmosphere. However once the frequencies have been removed they do not magically reappear so the CO2 at higher levels have nothing to work with. There is a little reradiation back to the surface from the energized CO2 molecules but this occurs only in the first 2 or 3 meters of atmosphere and is minor. Water vapour reacts in a similar manner but absorbs more energy than CO2 because it has more resonant frequency bands closer to the peak of the spectrum. The total greenhouse gas effect of CO2 is estimated to be 3 deg C which occurs in the first 50 meters of atmosphere by the 8% energy extracted and once removed from the spectrum there is no longer any energy left so increasing the CO2 has no effect. Now the big guy on the block is water droplets or aerosol. Aerosols which include smoke, volcanic ash, fly ash etc. behave entirely differently, they will absorb the entire spectrum and reradiate the entire spectrum just like any black body thus they do behave like a blanket, the gasses because they are frequency specific do not. As has been said the other massive factor in the energy balance is the convective behavior in the atmosphere. When air rises it expands and cools down by JT effect when it descends it is compressed and therefore heats up. It short the very large majority of backradiation comes from aerosols and very little comes from greenhouse gas molecules. One last thought there is a lot of energy transfer within the atmosphere but it must be remembered that when one atom or aerosol looses energy its temperature drops and the recipient of that energy will have a temperature rise so the net effect is zero, the only thing that effects the temperature of the earth is the transfer of energy between the surface and the atmosphere and in this regard I believe the convective heat removal is underestimated.
Alan, you write: “No, a sequence of excitation and emission occurs in a refractive medium.”
No, that process would scatter the light. A few photons do collide with atoms and are absorbed, then later re-emitted — but they can be re-emitted in any direction. The photons that do not collide with the atoms continue through the medium affected only by the change in the local permittivity and — in rare cases — magnetic susceptibility.
Cohenite, you have repeatedly accused me of ignoring the Pielke paper. I have not bothered responding to it because it doesn’t really raise any significant issues. Its main argument is that we need more data:
“Because of the issues presented in this paper related to the analysis of multidecadal surface temperature we recommend that greater, more complete documentation and quantification
of these issues be required for all observation stations that are intended to be used in such assessments.”
And in fact the very title of the paper reflects its thrust:
“Unresolved issues with the assessment of multidecadal global
land surface temperature trends”
This is not the giant-killer you seem to think it is. It’s not even particularly noteworthy. Yes, of course, we all know that we need to get more and better data. What’s so shocking about that?
Oh, and yes, there are latitudinal considerations in assessing AGW; I mentioned these long ago. There’s nothing surprising or even interesting in that observation.
Barry, I’d like to add an important point regarding your disquisition. Yes, water vapor has a larger effect than CO2, and water aerosols have an even larger effect, but those effects are historically constant and are part of the current equilibrium. The increase in atmospheric CO2 is changing that equilibrium, which is why we worry about it. You are quite correct in observing that the net direct effect of increasing CO2 is estimated to be at most 3ºC. However, we shouldn’t overlook the likelihood of positive feedback, which would result in a greater overall rise in temperature.
Chris Crawford: “No, you misunderstand the process. The fire emits, say, 1000 watts of power. Let’s say that 10 watts of that power strike the poker, heating it until it reaches thermal equilibrium and is emitting 10 watts of power. A small part of that 10 watts — say 0.1 watt — will hit the fire, causing it to heat up ever so slightly, so that it emits 1000.1 watts of power. So now the poker is receiving 10.001 watts of power — this is an infinite series that converges to a finite value. It doesn’t go infinite”
Disappointingly, I can only conclude from the above that you really don’t know what you’re talking about.
The fire emits 1000 watts of power. Which means it’s LOSING 1000 watts of power. The fact that it must be receiving at least 1000 watts in order to emit 1000 watts is irrelevant – if it receives power continuously it emits, and therefore loses, it continuously, but that’s besides the point.
The 0.1 watts it receives back from the poker DOES NOT mean that it now emits 1000.1 watts, it means that it effectively LOSES 999.9 watts.
You CANNOT create energy out of nothing, whether it’s 1000000 watts worth, or 0.000001 watts worth.
To suggest that the fire, or the Earth for thaqt matter, somehow GAINS energy from back-radiation, violates fundamental laws of physics – end of!
Newbie here and very inexpert so patience is required.
Am I right in characterising Kininmonth’s argument pivoting on the point that because the earth’s surface has the capacity to retain 66 w per m sqd in excess of that which is radiated into space then the so called green house gasses have a negligible role in forcing future temperature increases?
I understand that this may be a mischaracterisation if only because from the chart on which he bases his figures I can’t identify the net gain.
A question to Barry. I have read on other blogs that aerosols can have a cooling effect. I am thinking of the particulate matter that spews forth from volcanic eruptions which in great volumes seems to force a downward dip in temperature as was noted afet Mt Pinitauba (sp?)
Any help would be appreciated.
Peter, this is a simple matter of accounting — keeping track of where everything goes. There’s no magic, no energy being created or destroyed. The fire is generating 1000 watts of power and emitting 1000 watts of power — it’s stable. 0.1 watts bounce back to it — so now it’s generating 1000 watts AND absorbing 0.1 watts. That tiny increment of power causes its temperature to rise very slightly, so that it emits slightly more power — 1000.1 watts. That’s necessary for equilibrium. It’s all just a matter of keeping the sums straight.
Marco, Mr. Kininmonth has gotten the sums mixed up. The earth’s surface does not retain 66 Wm**-2 — if it did, it would heat up very rapidly. Place your face next to a 100W light bulb and your face will be absorbing maybe 20 watts — see how quickly your skin burns!
To understand the diagram, just go through it step by step, tracing the power flow. It all adds up if you keep the parts straight. Mr. Kininmonth has gotten them mixed up.
Thanks Chris for the reply.
What I meant was that I couldn’t identify his 66 watts as the top of the chart shows a balance of energy in/energy out. Thus my question asking if I had fairly characterised his argument as to my understanding without this surplus then his argument fails.
Yes, his 66 watts comes out of nowhere. I’m sure that, if we dig around, adding and subtracting pairs of numbers selected from the entire set of numbers on the graph, we’ll eventually find a combination that yields 66. But the logic behind that combination is unlikely to make sense. But perhaps we should give Mr. Hininmonth the opportunity to himself explain where the 66 came from.
Putting it another way:
A variation of the 2nd Law of Thermodynamics – the Clausius statement: Heat cannot spontaneously flow from a material at lower temperature to a material at higher temperature.
Therefore the fire cannot heat the poker to a temperature higher than itself, and it follows that the poker cannot, by any means, make the fire any hotter than it is.
No, Peter, that’s not correct. Here’s the logical sequence, and you tell me which step (or steps) is incorrect, in your opinion.
1. The fire heats the poker to a temperature lower than its own.
2. The poker radiates power because it’s hot.
3. That power travels out in all directions.
4. Some of that power hits the fire.
5. The fire absorbs that power.
6. Because the fire has absorbed additional power, its temperature rises.
Marco you are quite correct aerosols have both a positive and negative forcing effect. During the day they intercept incoming short wave radiation and since they radiate as a sphere a lot of this energy goes straight back into space, so less gets to the surface ( negative ) however it does capture long wave outgoing and radiates some of it back ( positive). During the day it is net negative i.e. cloudy days are cool days but at night clouds are net positive, cloudy nights are warmer than clear nights. Sustained high levels of aerosols ( volcanoes ) will have a net negative effect.
Chris I think you skipped the part where the first 50 meters of atmosphere removes all the available energy in the CO2 resonant wavebands. Thus it is in a saturated stable equilibrium, any transfer in the atmosphere without any contact with the surface is net zero effect, again completely stable. Your remark about water vapour being historically stable is unquestionably not true. At -50 deg C the saturated water vapour content of the atmosphere is 34 ppm at 25 deg C it is 25 000 ppm so from the south pole to the equator we have quite a large variation in concentration. Now if the world warms up there will be a considerable change in this concentration thus water vapour is not constant irrespective of temperature, far from it. With respect to this massive change in concentration the same laws of physics apply to water as to CO2 so how come if CO2 doubles from 300 to 600 we will have a runaway disaster but water can change from 34 to 25 000 without any adverse effect.
Barry, you’re right, I didn’t mention the depth-response of CO2, but I’m not following your assertion that “the first 50 meters of atmosphere removes all the available energy in the CO2 resonant wavebands.”
If that were true, then adding CO2 to the atmosphere wouldn’t have any effect, because all the available energy would have been absorbed. Perhaps you’re talking about absorption and re-emission at low altitudes? In any event, I didn’t think that the cross section for a single CO2 molecule for its IR band photons was high enough to permit 400 ppm to absorb ALL the incident IR in just 50 meters. Do you have numbers on that?
I think you misunderstand my remark on water vapor. Of course it has high derivatives, both spatially and temporally. My point was that water vapor, while a more important GHG than CO2, is not being changed by humankind in the way that CO2 is being changed. For the purposes of AGW analysis, water vapor can be treated as a constant factor (although of course in modeling it plays a large role).
1) The temperature of the fire (or the Earth, or any other body) is determined by the difference between the rate of energy input and the rate of energy output.
2) Heat cannot flow from a colder body to a warmer one by any means – be it conduction, convection, radiation or a combination thereof, without work being done (like in refrigeration)
Your argument violates both these fundamental laws, and therefore cannot stand.
Peter the solution to this discussion depends on the configuration. You are basically discussing Stefans law which states the net energy flow between two bodies A & B is in relation to the 4th power of Temp A minus the 4th power of Temp B, Clearly net energy cannot flow from a cool body to a hot body but take away B and all the energy from A is lost thus it reaches an equilibrium temperature dependant upon the rate of energy being generated in A, now if you keep the energy at a constant rate but interpose B some heat is returned to A so its temperature must go up to maintain the same energy outflow. One caveat here which may be mudding up the water if the poker is actually surrounded by the fire it will not increase the temperature of the fire the two bodies A & B must be separate for this law to apply.
Peter, I’m disappointed that you refused to respond to my line of reasoning, preferring instead to simply re-state a form of 2nd Thermo. But at least this permits me to explain your misconception in your own terms. You are correct in observing that “Heat cannot flow from a colder body to a warmer one by any means – be it conduction, convection, radiation or a combination thereof, without work being done”. What you are neglecting is the fact that work *is* being done. You probably have some difficulty with this idea, because you may not be familiar with the thermodynamic definition of ‘work’. In this case, the work being done is the original transformation of chemical energy into heat energy inside the fire. And that work can be used to move heat from a lower-temperature reservoir to a higher-temperature reservoir — exactly as I have explained.
Sorry Peter, but you just do not know what you are talking about. Chris is absolutely correct.
1.) You say, “The temperature of the fire (or the Earth, or any other body) is determined by the difference between the rate of energy input and the rate of energy output.” No! The rate of change of internal energy is determined by this difference. If all of the change goes into temperature change, then the rate of change of temperature (not the temperature itself) is determined by this difference. Many of the posts here over the past week have gone completely off the rails by confusing rates of change with levels.
2.) You say, “Heat cannot flow from a colder body to a warmer one by any means – be it conduction, convection, radiation or a combination thereof, without work being done (like in refrigeration)”. As Chris has pointed out, this only applies to NET transfers.
It is vital to realize that the 2nd Law is at root probabilistic and statistical. It is only when you sum all of the energy transfers between two bodies of different temperatures that you get the (virtual*) certainty that there is a net transfer from the warmer body to the cooler body.
When there is no temperature difference between the bodies, 50% of the interactions (whether conductive or radiative) transfer energy one way, and 50% the other way, so there is no net transfer. If one body is slightly warmer than the other, then, say, 51% of the interactions transfer energy from the warmer to the cooler body, and 49% transfer from the cooler to the warmer body. It is the 2% difference that yields a net energy flow from the warmer to the cooler body. (And as the temperature difference grows, the percentage difference grows as well.)
This is true for both conductive interactions, where the atoms are directly colliding with each other and transfering energy that way, and for radiative interactions, where photons act as the intermediary.
These concepts are easy to verify, both experimentally and conceptually. It is very easy to confirm in the lab — I’ve done it — that the thermal radiation from a body does not depend on the temperature of any bodies it is radiating toward. The argument that a cooler body cannot radiate any energy toward a warmer body demands a different result.
And conceptually, the argument that a cooler body cannot radiate any energy toward a warmer body requires that bodies have “knowledge” of what they are radiating towards. What is the mechanism for obtaining and processing that knowledge? And since this radiation travels at the speed of light, wouldn’t the inhibiting signal have to come in faster than the speed of light?
*Given the probabilistic nature of the 2nd Law, even this is not an absolute certainty, but on any macroscopic scale, the odds against something different happening are so vast they make the odds of striking it big in the lottery seem like a sure thing.
Even if you surrounded object A with a perfect, lossless reflector which INSTANTLY reflected ALL the energy radiated from A back to A at the same wavelength, you would be doing nothing more than effectively reducing the rate of energy loss of A to zero. You would NOT be increasing the energy input to A.
And as an analogy to my point 2, shining a torch at a brighter light does not increase the intensity of the brighter light.
Even if you surrounded object A with a perfect, lossless reflector which INSTANTLY reflected ALL the energy radiated from A back to A at the same wavelength, you would be doing nothing more than effectively reducing the rate of energy loss of A to zero. You would NOT be increasing the energy input to A.
And as an analogy to my point 2, shining a torch at a brighter light does not increase the intensity of the brighter light.
Peter writes: “Even if you surrounded object A with a perfect, lossless reflector which INSTANTLY reflected ALL the energy radiated from A back to A at the same wavelength, you would be doing nothing more than effectively reducing the rate of energy loss of A to zero. You would NOT be increasing the energy input to A.”
Yes you would. I assume you’re still talking about an object that is generating heat at some power P. Basically, what you’ve set up is a closed system: the object A is getting power coming into and there is no way for the power to escape. Therefore the temperature will rise indefinitely.
Oh yes, I forgot this:
“shining a torch at a brighter light does not increase the intensity of the brighter light.”
Actually it does, but the amount of increase is very, very tiny.
Curt: “And conceptually, the argument that a cooler body cannot radiate any energy toward a warmer body requires that bodies have “knowledge” of what they are radiating towards.”
I never argued that a cooler body cannot radiate towards a warmer one, merely that the radiation won’t be absorbed by the warmer one.
Chris: “One caveat here which may be mudding up the water if the poker is actually surrounded by the fire it will not increase the temperature of the fire the two bodies A & B must be separate for this law to apply.”
Let me see if I’ve got this straight – if object A and object B are separate, and the only thermal transfer between the two is bwo radiation, A can heat B which in turn can heat A, but if B is surrounded by A then that cannot happen – even though B is hotter than it would be were they separate, and transfer can be bwo conduction and radiation?
How does that happen?
It seems that you occupy a very strange universe.
Peter, you said, “I never argued that a cooler body cannot radiate towards a warmer one, merely that the radiation won’t be absorbed by the warmer one.”
So how does the receiving body know whether a given photon is a less energetic one from a warmer body (which by your logic should be absorbed), or a more energetic one from a cooler body (which by your logic should be — what — reflected)?
Remember that all bodies radiate away photons with a distribution of energies. Can you propose a mechanism whereby a photon of a given energy level carries with it information about where on the distribution of the radiating body it came from (does it carry a certificate)? And how is this information transmitted to the receiving body so it can make its decision?
“It seems that you occupy a very strange universe.”
Peter, the comment to which you object was made by Curt, but his meaning is clear. He’s trying to eliminate a more complicated situation that would be messier to analyze. Inasmuch as you’re having so much difficulty with the simpler case, I think it best that we keep things as simple as possible.
Oops! And *I* misattributed it, too! The author of the statement in question is Barry, not Curt.
The higher the temperature of an object, the higher energy photons it tends to emit, and the less its tendency to absorb lower energy photons – from whatever the source. Entropy increases.
Peter writes: “The higher the temperature of an object, the higher energy photons it tends to emit, and the less its tendency to absorb lower energy photons”
Peter, where do you get this notion? The first half is right, but the second half is just crazy. What possible physical mechanism could make this happen? This contradicts what we know about absorption processes. Didn’t you just make this up?
Well Peter, maybe we’re making a little progress. You are starting to talk in terms of tendencies, which is a start to understanding the probabilistic nature of these things.
But you still have not come to grips with the key issue, which is that your argument requires some decision-making mechanism between the two bodies about whether certain photons should be accepted or rejected.
Two other implications of your argument: First, if the hotter body somehow could decide not to absorb any of the photons from the cooler body, it would have to reflect them away. If so, this would be detectable and measurable. Can you cite any work that demonstrates this phenomenon?
Second, if your argument were true, the rate of power transfer would not be proportional to the differences in T^4. You would get a sudden step in power transfer when one body got slightly hotter than the other, because (according to your argument) it would suddenly be able to reject all of the photons from the other body.
“It seems that you occupy a very strange universe.”
When you get down to the world of quantum mechanics, it is indeed a very strange one. It obeys the laws of physics, in that a hot body will heat a cold one overall, but at the same time you will get a photon being sent from a cold body to the hot one.
If you want to read more about the quantum view of the world, it only gets more and more bizarre. For example, a single photon of light passing through two slits at the same time.
For everybody UC Berkeley have a great series of podcast lectures. One of them Physics for Future Presidents is particularly apt.
How about we all have a listen to the these:
http://webcast.berkeley.edu/course_details.php?seriesid=1906978397#17859
The course creator Richard Muller is also a Steve Short type skeptic of climate change and proponent of nuclear power so I guess you can consider him free of lefty bias.
So why not listen to the lectures and then see how your theories fit into real physics.
And another resource:
Physics 10/LS C70V Descriptive Introduction to Physics
http://muller.lbl.gov/teaching/Physics10/PffP.html
No mate you are barking up the wrong tree. You are a fraud. You are an idiot. Skeptics understand the global warming idiocy enough to know its a lie.
Now lets have that evidence.
Chris I don’t know if you are still following this blog I have been elsewhere for a couple of days. Your question re the absorption of CO2 at 400 ppm is explained best in the paper by John Nicol – Climate Change, if you can not find it his e mail is jonicol@netspace.net.au it is the best paper dealing with this subject using the fundamental laws of physics. The law you need is Beer’s law to calculate the mean path of the CO2 resonant frequencies.
Again I think you missed the implication of “At -50 deg C the saturated water vapour content of the atmosphere is 34 ppm at 25 deg C it is 25 000 ppm so from the south pole to the equator we have quite a large variation in concentration. Now if the world warms up there will be a considerable change in this concentration thus water vapour is not constant irrespective of temperature, far from it. With respect to this massive change in concentration the same laws of physics apply to water as to CO2 so how come if CO2 doubles from 300 to 600 we will have a runaway disaster but water can change from 34 to 25 000 without any adverse effect. “ It really does not matter whether the cause is anthropogenic or not, first study the effect of the change then figure out where it comes from. If the atmosphere is as sensitive to concentration changes as that ridiculous empirical formula published by the IPCC then this must apply to water vapour as well as CO2 and the water vapour content of the atmosphere is changing regionally by massive amounts how can you possibly put this into a computer model when the dew point is all over the map on a daily basis which is totally unpredictable.
Barry, I think you misunderstand the point that I was making. My point was that we cannot attribute recent changes in global temperature to water vapor, because historically (over several hundred years) there is no evidence to indicate that it has increased. Yes, there are big differences between water vapor at the poles and water vapor at the equator — that’s why the poles are warming faster than the equator.
“how come if CO2 doubles from 300 to 600 we will have a runaway disaster but water can change from 34 to 25 000 without any adverse effect.”
Indeed, if water vapor concentrations increase, they will cause enormous problems. In fact, this is another one of those nasty positive feedback factors. All by itself, a doubling of CO2 concentrations will increase global temperatures by only a few degrees C. But a small increase in global temperatures will ALSO put more water vapor into the air, which in turn will lead to larger increases in temperature. I’m not at all dismissing the effect of water vapor — it’s one of the factors that magnifies the danger of CO2 emissions.
“how can you possibly put this into a computer model when the dew point is all over the map on a daily basis which is totally unpredictable.”
This is the difference between weather and climate. Yes, weather variables change rapidly. But for purposes of predicting climate (not weather), you don’t need to track these variables with that much resolution. You can rely on data averaged over a period of time and apply standard diurnal and annual variations.
No water vapour won’t cause enourmous problems if it increases. This is the curse of the watts per square metre business again.
Water vapour magnifies the variation of the sun on the troposphere. But it is the method by which the oceans cool down. This is something that you miss if you attempt to process the data all the way to watts per square metre.
Looking at the more meaningful measure of imbedded oceanic energy, it is the water vapour which is cooling the oceans down. Transporting heat into space.
It is an EFFECT of excessive warming, seen from the oceans point of view and not a cause. Seen from the troposphere’s point of view it is THE cause of warming but when it overheats it is bringing the problem to an end. Since it is cooling the oceans.
From the stratosphere’s point of view it is an immediate cooler.
I’m telling you be quits with WPSM. It robs all perspective. It makes people stupid. You could start off with a great understanding of earth systems and weather. And the WPSM model would whittle it away over time.
O.K. Graeme I certainly follow your logic and it is very reasonable but if all this warming is being transported up into the troposphere by water vapour why have we not seen the increase in troposphere temperatures in either the UAH or RSS data as predicted by the IPCC in their 4th report. My embedded point here is that both water vapour and CO2 level off in their forcing effect at a relatively low ppm level < 100 ppm this is proven in John Nicol’s paper ( and many others) this does not include water as and aerosol only as a gas. Thus the lack of any change in forcing effect with a large variation in concentration is in conformance with the laws of physics and observations.
I do agree with you about WPSM , IPCC waffles on about them ad nausium page after page and it is all just smoke and mirrors.
Bill is definitively correct re: Back Radiation, it cannot meaningfully occur for two reasons.
1. The emissivity of non-reflective solids is 3 orders of magnitude larger than low pressure, low temperature GHGs H2O & CO2. Even if the atmosphere is hotter by tens of degrees C, the surface OLR will render insignificant any returning radiation of GHGs in their direction.
2. The fact that the air is heated by OLR is definitive proof that this region of the atmosphere is not in thermal equilibrium. Incoming flux exceeds outgoing flux, if minutely, and the result is increased kinetic energy of the entire molecular complement of the region, increased temp. This means the GHGs lose the absorbed energy to its neighbors by conduction and do not emit in direct relation to their rate of absorption.
All of this is Thermodynamics, which is not introductory physics and is manifestly not required of Climate Science grads at any level, even those with physics concentrations.
It now becomes clear how Ender’s physics has become so warped.
Ender, you really listen to stuff from Berzerkeley???