Over on the suggestions page, talkshop contributor ‘mydogsgotnonose’ has posted an interesting synopsis of his understanding of constraints on the co2 greenhouse effect. I think this is worth discussing, so I’m putting it here as a post in its own right.
Limits on the Co2 Greenhouse Effect
MDGNN – June 2012
There is probably no net CO2-AGW. If you look at Nasif Nahle’s work, it could even be slightly negative. Basically, the assumption by the IPCC that all the absorbed Infra Red radiation (IR) is directly thermalised is wrong.
The basis of this is two-fold. One is empirical.
This link shows that >200 ppmV [CO2] there is no increase in absorptivity/emissivity [assuming Kirchhoff’s law at equilibrium]. These data are routinely used in furnace design and are correct in that they work.
Furthermore, the experiments were done using a heated/cooled container and there are good theoretical reasons that the real process is absorption then pseudo-scattering to give indirect direct thermalisation at the walls of the container, so the real process is the effectiveness of the CO2 at scattering energy to the container walls and vice versa.
The theoretical reason is that there is no direct process for transfer of absorbed quanta in GHG molecules by multiple collisions to symmetrical N2 and O2 as apparently claimed in climate science.. Also the Principle of Indistinguishability means that molecules have no memory so Local Thermal Equilibrium (LTE) is restored once an already excited molecule emits the same quantum: no direct thermalisation. This is kinetic selection in that the energy is transferred by multiple pseudo-scattering events as if the GHGs were a heat transfer medium, only stopping when the quantum is absorbed/thermalised at a heterogeneous interface, or heads off to space.
In the atmosphere, the ‘container’ is clouds and bare aerosols giving the impression of direct thermalisation. Nahle has shown theoretically from partial molar specific heat data [implying a container] that the apparent absorptivity slightly decreases as [CO2] rises.
This reference is an interesting discussion where the conclusion is the IR is pseudo-scattered, also possibly by resonance emission of existing excited molecules:
The ultimate arbiter is the experimental data of Hottel and Leckner. Clouds are grey bodies because the absorbed band specific IR is thermalised over many more wavelengths, so again making a very different heat transfer problem than the IPCC claims. Thus cloud under surfaces will emit specular IR light in the atmospheric window back to the Earth whose energy will have originally been partly CO2 specific. On the contrary, there will also be transfer in the other direction so it probably cancels out.
Basically, the IPCC has got it completely wrong in that they fail to realise that the Tyndall and PET bottle experiments are driven by the container and the pressure rise at constant volume. There may be some direct thermalisation but Nahle’s recently reported Mylar balloon experiment showed no detectable thermalisation:
A key rider to this discussion is that as the atmosphere thins and has fewer clouds, the IR emitted by clouds and warm air will preferentially escape to space because as it is pseudo-scattered, it is selected to escape UP. This means that as height increases, the emissivity DOWN tends to zero.
Thus the Schwarzchild two-stream approximation cannot be applied at Top of Atmosphere ( TOA) and emissivity DOWN will be <<absorptivity DOWN above the cloud level.
At Bottom of Atmosphere (BOA), the boundary condition is that only the net IR UP is important in that the rest of the heat transfer is conduction and convection, the total being 160 W/m^2. In effect the emissivity of the earth’s surface is <<1 and radiative flux only exceeds [conductive plus convective] flux at ~100 °C [see McAdams’ Heat Transfer for example. Thus the IPCC claim that there is a radiative equilibrium between a ‘blackbody’ surface in equilibrium and ‘blackbody’ air is completely wrong.
At TOA there is zero DOWN IR. At BOA, UP IR = 63 W/m^2 [data from the Trenberth cartoon**] and it is claimed that 40W/m^2 of this goes through the atmospheric window. Let’s assume this is correct. The net result is that the climate models artificially increase heat in the system by a factor of [240+333-240]/240 = 1.39 and the IR bit by a factor of [23 +(333-240)]/23 = 5.04. This shifts the calculation to IR dominance whereas the real atmosphere is dominated by convective processes; thus the incorrect model is the origin of the unphysical positive feedback.
In summary: thermalisation is indirect and because the scattering of IR from the Earth’s surface asymptotes at ~200 ppmv [CO2], there can be no net CO2-(A)GW in the post ice age World.
** www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/TFK_bams09.pdf
============================================================
I’ll add to this something Ned Nikolov said in email which is relevant and adds some background on the way radiated energy is distributed in the atmosphere:
IR radiation emitted to space by the Earth-atmosphere system equals
the SW solar radiation absorbed by the system, which is about 238.3 W
m-2 (the 240 W m-2 value is based on the old solar constant). It is
also true that the atmosphere emits IR radiation in all directions.
However, the atmosphere is not vertically homogeneous in terms of
pressure and density. There is a huge pressure/density gradient between
the surface and the stratosphere. The LW atmospheric flux measured at
the surface originates virtually 100% within a 1km layer adjacent to the
surface. The outgoing LW flux observed from space originates primarily
in the top layers of the troposphere, which are much colder and also
lower density and thermal emissivity compared to the bottom layers. On
average, the vertical temperature gradient (lapse rate) is caused by the
pressure gradient. Lower layers in the troposphere have higher pressure
and higher temperature (as well as higher thermal emissivity) compared
to higher layers, which results in a larger IR down-welling flux (back
radiation) at the surface than at higher levels in the atmosphere.
The difference between outgoing and down-welling IR flux is always
negative and its absolute value increases with altitude – it’s about 43
W m-2 at the surface and reaches 238 W m-2 at the top of the atmosphere.
[edits 6th June 2012, see comment. –Tim]
Tallbloke's Talkshop 
In a dense hot CO2 atmosphere like Venus’, the summed effect of LTE everywhere will be rapid radiation-mediated equalization of heat energy and hence temperature across the globe. That includes the poles and nightside. Which is what is found.
Hi all. I’m getting 404’s on the links.
Thanks Harriet, fixed now.
Brian H: I doubt it. If that was the case, there wouldn’t be several hundred km/h winds howling round slowly revolving Venus busily shifting energy from dayside to nightside.
Nikolov = same as me but I am trying to establish the IR physics/statistical thermodynamics which explains it.
The reason I have done this is that I was ambushed by [Met Office?] modellers on BH. They used a trick; a 100 W heated disc, insulated at the back face, black body front face and infinitely conductive transmits IR to another disc, black body on both faces. This is surrounded by a perfectly absorbing container at absolute zero.
What is the heat transmission from the inner face of the 2nd disc?
The text book answer they claimed was 100 W based on the 100 W being perfectly absorbed then heating the second disc to put out 100W by radiation on both sides! i pointed out it had to be 50 W eacjhe side for energy conservation so the 1st disc had to heat up to compensate. Then the boot boys came in! This is how they justify ‘back radiation’=TOA UP! .And they then went on to crow that this is the ‘text book answer’.
I pointed out that for the 2nd disc we have IR IN, being conducted with no kinetic energy gradient to the other face where there is zero impedance to space. So, Kirchhoff’s Law of Radiation does not apply.because it only works for equilibrium. There is a good statistical thermodynamics’ / quantum explanation of this..
Thus there is no ‘back radiation’. The BOA heat transfer in the Trenberth cartoon is similarly incompetent heat transfer analysis. Only net flows are real. Pygeometers measure just the temperature signals because of the shield at the back of the detector.
This is the biggest mathematical modelling and experimental cock up in History and it’s about time it’s exposed for what it is, amateurs who got it wrong and are refusing to admit their fault. This is not science, it’s alchemy.
As I understand the standard explanation it is this.
Disc 2 at first emits 50W/m^2 from each side. The 50 emitted in the direction of plate 1 is absorbed and along with the 100W/m^2 heating it, it emits 150W/m^2 towards plate 2. Plate 2 then radiates 75W/m^2 from each side and so plate 1 then receives 75W/m^2 from plate 2 plus the 100 heating and so emits 175W/m^2…
After several more iterations you get plate 1 emitting 200W/m^2 and plate 2 emitting 100 W/m^2 from each side.
Any problems so far? Apart from the obvious observation that not all the radiation from plate 1 hits plate 2. And that the earth’s surface and atmospheres aren’t flat bb plates or anything remotely resembling them. And that the space in between atmosphere and surface isn’t a vacuum. 🙂
Mydog, I have always been impressed by your knowledge of practical thermodynamics since your earliest posts on BH, even with the awareness that my own knowledge of such things is woefully deficient. But to me and, from comments I have seen on the blogs, to many others as well, you seem to be saying something important. Could now be the time to let your light shine free, and debate openly with the climatologists under your own name, as Nikolov and Zeller or Steve McIntyre already do? It could be a turning point in the AGW debate, particularly if other qualified people agree with what you are saying and support your theory.
Hi Tallbloke: the disc thought experiment is as you say so long as you admit to the ‘back radiation’ concept. However, this breaches the 2nd Law of thermodynamics by creating a perpetual motion machine of the 2nd kind. [I believe so because the atmosphere expands].
The explanation for no back radiation is that these dumbos have forgotten the caveat in all the text books about Kirchhoff’s Law of Radiation applying only at thermal equilibrium and an infinitely conducting material with radiant energy filling a continuously emptying quantum intermediate state is not at equilibrium. As I wrote above, there is an explanation of this, essentlally showing how Prevost exchange works to regulate radiative flux and Claes Johnson has created the difficult to follow new physics from another direction.
A simpler explanaton of the 100w from the outer face of plate 2 is that in this idealised experiment, 100w is input to the system, and as described the only output from the system is the outer face of plate 2. It must therefore be 100w. QED
steveta_uk: agreed otherwise you breach the 2nd law by creating extra energy. But bear in mind, what happens at BOA is conditioned by what happens at TOA. The two-stream approximation says that you get 240 W/m^ DOWN so they artificially claim the IR from the earth’s surface has to be S-B black body.
This breaches a century of experimental data but because we were dealing with people without the process engineering experience, they made the wrong guess. Also the assumption of black body by the lower atmosphere is wrong, To get the sums to balance they must fiddle the data somewhere.
TB,
Possibly a good thing with this AGW/CO2 debacle is that now ALL of science is under the microscope.
I could never understand how temperatures rising and CO2 being blamed and yet the heat to generate CO2 was NEVER a factor nor all the other sources of heat we generate that does not give off CO2 and yet temperature hype IS the factor?
Currently a hard freeze is hitting Utah and Nevada and the glaciers are refusing to melt which is putting a massive strain on people who rely on this water.
http://iceagenow.info/
Mydogsgotnonose,
My evidence is that our planet started out with 2 kilometers more water by salt traces as the denominator. Considering ice in space has almost the exact same consistency of our oceans.
http://www.esa.int/SPECIALS/Herschel/SEMER89U7TG_0.html
As rock and sand is slowly exposed over the years, you do have greater absorption and release of heat absorbed by these materials compared to the planet totally underwater. This explains many factors of erosion and mountain formation.
But this is ONLY my own research and definitely NOT the consensus view.
Brian H: on Venus, the high lapse rate heating and very small maybe zero solar heating at the surface means the planet’s surface temperature is the same day and night.
The high albedo is the result of an optical process which van der Hulst and Sagan didn’t realise existed. It’s why thunderclouds on Earth have similar albedos, ~0.9.
I have just had an interesting thought. Cloud droplets getter most local CO2. This means that the IR emitted by the system is lacking in the CO2 bands [seen experimentally], so the high absorptivity of clouds getter the CO2 IR emissions from the clear atmosphere and transform them to CO2 free IR,i.e. they actively reduce the IR specific bands.
That means the clouds negate the effect of the CO2 in the volume fraction of air that is occupied by the clouds and in the air above the clouds. This is effect a filter, reducing CO2-AGW to the atmosphere below the clouds and may explain why the Hottell and Leckner experiments show a 200 ppm limit: it’s when the extra warming at the boundary actively reduces the CP2 band energy in the system.
This seems to suggest a still further reduction of the effect of extra CO2: it’s a self limiting GW process perhaps sufficient to help a bit in getting out of ice ages, but no more! Needs some more thinking.
Do I detect agreement with Huffmann’s Venus/Earth comparison here?
Hi oldbrew: and so there should be, it’s purely lapse rate except the Earth is heated at the surface so there’s much more convection to overturn the GHG-(A)GW.. Venus is heated from above with no convection at the surface and there is no CO2-GW.
Thanks MDGNN. If the fundamentals are right the details can be fitted around them.
PS oldbrew, my comment about Venus should be viewed relative to the Graeff heating which would cause convection at the surface if true.
“Graeff heating which would cause convection at the surface”
I’m not at all convinced by Graeff, but even if it is true, then it certainly cannot cause convection. This would imply work being done with zero energy input.
steveta_uk: you may be right in that the Graeff phenomenon occurs when you inhibit convection.
Now imagine Venus where convection is inhibited because the heating is not from the base.
Graeff warming will occur more easily. perhaps you get ‘bumping’ when buoyancy exceeds a critical level!
Dr.Nasif Nahle´s web page: http://www.biocab.org/
Mr. Nose please stop discussing the exchange of watts (q) with those folks and instead establish the temperature of the 1st disc and go from there. Proper heat transfer equations or even simple ones stop all the nonsense about back radiation. Heat transfer is only in one direction.
oldbrew asked: “Do I detect agreement with Huffmann’s Venus/Earth comparison here?”
You would be wrong to think so. From my Venus/Earth comparison, I say Earth’s atmosphere is not heated from the surface (obviously neither are the atmospheres of Venus or the outer gas giants), and from fundamental physics I say all of the solar radiation absorbed, by either the atmosphere or the surface, is turned into heat energy, precisely by the absorption process–this is the key to physically understanding the Stefan-Boltzmann formula.
MDGNN, that’s one very needed post! And couldn’t agree more with Ned’s summary:
“The difference between outgoing and down-welling IR flux is always
negative and its absolute value increases with altitude – it’s about 43
W m-2 at the surface and reaches 238 W m-2 at the top of the atmosphere.”
Those are the same figures I keep coming up with (+/- a few). TB, remember that energy budget accounting spreadsheet i sent you? Same figures, 45 wm-1 net up at the surface, 239 out at the top. You can approach this problem from many different directions but those are the figures you will end up with in the end.
Thanks Wayne. I’m not a professional in this area, just a retired ideas’ junkie who sometimes gets lucky….. 🙂
MDGNN, I was just psyching-up to ask you about the CO2 in water/ice clouds, especially regarding thermalisation, when I read your post.
Is the thermalisation of CO2 IR bands likely to be more efficient at the surfaces of the condensed phases, as it is in better physical contact with, primarily, water/ice? [Helping to make it a ‘grey’ body, as you mention.]
Similarly related, will any significant energy transfer occur by quantum-tunneling [for want of a more precise term] between absorbing-emitting molecules that have very close, but not identical, vibrational/rotational energy levels?
I ask that last question because dissolved CO2 does form carbonic acid in clouds, and I would expect that to have some influence on the observed IR bands of interest, quite apart from the effects of the dimensions of the cloud droplets/crystals.
Michael Hart: I know there is Japanese research on the gettering of CO2 by cloud droplets. H2CO3 is a weak acid and in the oceans, ~90% of the CO2 is still the molecule. The key issue is the absorption in depth for the mass of droplets convolved by optical scattering increasing path length. Not being a physicist, I can’t comment on QMT except to nod my head that I’ve heard of it!
The reverse process, emission, is interesting. Normally you’d expect IR emission in a strongly absorbing substance like liquid water to be from a micron or so, and at low [CO2], it’ll be dominated by H2O. The key issue is that in free air there is a given ratio of H2O to CO2 whereas in the liquid phase with optical scattering from the droplet surfaces [depth of evanescent wave controls this], that ratio is controlled by the surface composition. But then you have multiple scattering on the way out from droplets behind the front surface. The observation is that the CO2 spectral lines are minor in the cloud spectrum.
mkelly: I simplified things by looking at the impedances: zero radiative impedance then zero conductive impedance meaning the 100 W from the first disc is emitted from the second disc’s outward surface.
What these people have forgotten is that Kirchhoff’s law only applies at equilibrium so the emissivity of the inner face of disc 2 is zero. The practical reason is that none of the quantum density of states at the surface can be filled by kinetic energy from the interior so there can be no ‘back radiation’.
The next stage is to show why this is the case in the atmosphere and it comes naturally from the indirect thermalisation concept.
As for the two stream approximation lower down, it will work correctly in terms of the arithmetic but it’s so minor compared with convection, you can probably ignore it.
Incidentally, Trenberth’s figure for the atmospheric window of 40 W/m^2 is at variance with the satellite measurements which show 66 W/m^2. But then you’d have -3 W/m*2 net IR from the Earth’s surface This discrepancy is probably the fiddle needed to keep the imaginary back radiation idea going.
This paper is interesting because he talks of the two stage convection then radiation model: KNMI_voordracht_VanAndel.pdf
I thought this was an interesting comment on Willis’ recent post:
cba says:
June 7, 2012 at 1:11 pm
Oh No! It’s worse than we thought…
the obvious cause of albedo variation is cloud cover fraction which does affect both incoming and outgoing. It’s not the only cause of albedo variation. Evidently, one can vary the reflectivity of clouds by varying the size of the nucleation particles. Use smaller particles and you get higher reflectivity out of the same patch of clouds and that doesn’t have an effect on LWR like increased cloud cover fraction.
As I recall, Lindzen has an Iris effect theory using this sort of albedo variation.
For the whole Earth average, balance for incoming and outgoing power happens at about 239 W/m^2 coming in and going out. Radiation leaving the Earth’s surface at the average T value, 288K, results in an escape rate of around 270 W/m^2 for power leaving the troposphere which means that about 70% of the surface emission escapes or is replaced by atmospheric emission on the way out. With about 70% of surface radiation escaping one can see that to reduce 270W/m^2 down to 239 W/m^2 would require a reduced output from the surface of around 43W/m^2, dropping 390 down to 347 W/m^2 which is equivalent to a radiating temperature average of around 280K. That would mean the surface T would be down around 280K or a mere 7 deg C about freezing.
What is happening here is that around 60% of the Earth has clouds and 40% is clear sky. Clear skies contribute around 270W/m^2 and the overall average is around 239. Working through a weighted average (60/40), one can determine an average emission for cloudy skies. This comes out to around 218 W/m^2 of radiated power coming from cloud tops that needs to escape the atmosphere. This corresponds to around 249 K or -24 deg C. That’s the atmospheric temperature about halfway to the tropopause.
Consequently, while losing cloud cover, one increases the radiated power leaving the Earth as well as reducing albedo and allowing more incoming solar power. If one assumed we totally lost all cloud cover and wound up with an Earth albedo of 0.08 (due to all that of water on the surface), we’d only have 313 W/m^2 coming in to be absorbed and to be balanced. If we assume the same fraction of surface emissions make it through the atmosphere (70% for clear skies), then the surface would have to heat up enough to radiate 450 w/m^2 and that corresponds to a T average of 298K, only 10 degrees warmer than the 288k mean.
anyone here starting to see how lunatic claims of 6 deg C rise due to a somewhat minor increase of a trace gas like co2?
TB: the aerosol optical physics used in climate science to predict pollution increases cloud albedo is only partially correct. It works for thin clouds because ~50% of diffusely scattered light is backscattered. But as the clouds get thicker, the albedo from this process asymptotes.
There is however, a second process which has not been considered by the IPCC physics. You get it here: http://www.gewex.org/images/feb2010.pdf
Page 5 is a paper by US Cloud Physicist G L Stephens who noted from satellite data that ~40% of low level clouds have ~25% greater average optical depth than predicted from the droplet size and LWP. He also noticed that the climate models assume twice real low level cloud optical depth, ~10% higher albedo, than reality.
This is the prime method used to offset the greatly exaggerated GHG-GW with the net AIE being used as a variable to offset the greatly exaggerated GHG-AGW.
The explanation of this second optical effect is that it is from the bimodal droplet size distribution. The net AIE is the opposite sign to that claimed and with zero net GHG-(A)GW is probably the real GW/AGW mechanism.
Everyone who relies on the ‘Twomey Effect’ should understand it explains a small part of the physics. He realised this but in 2004 in the build up to AR4, NASA swapped his physics with the fake ‘surface reflection’ claim: http://geo.arc.nasa.gov/sgg/singh/winners4.html
You get claims of 90% albedo from ‘increased surface reflection’. This is bunkum – such clouds have large droplets pushed to the top by convection. And yes I have worked out the physics..One rider is that all the derived satellite data are wrong because the algorithm to convert albedo to optical depth is based on the incorrect Sagan physics. Thus a bright cloud with a given LWP could be a polluted uniimodal cloud or it could be an unpolluted bimodal cloud.
As for the comment above, you can see the major errors imposed by the ‘two-stream idea that the earth is radiating as a black body. It is not and cannot except if you had no atmosphere. The real net IR is much lower and above we have 43 W/m^2, much less than the atmospheric window meaning much of the latter has to come from convection changing to radiation in the upper atmosphere.
Climate science is in a mess because they offset broken radiation physics with broken cloud physics.
harrydhuffman (@harrydhuffman) says:
June 7, 2012 at 9:36 pm
“From my Venus/Earth comparison, I say Earth’s atmosphere is not heated from the surface”
Is this a semantics problem? MDGNN said “it’s purely lapse rate except the Earth is heated at the surface”.
I took the ‘at’ to mean the incoming solar radiation was reaching the surface, not that the earth was being heated from the interior (which appears to be Mr Huffmann’s interpretation of MDGNN).
Reblogged this on Quid Sapio.
oldbrew. you can use the Venus comparison in another way..
The ‘back radiation’ concept for the Earth adds the black body IR from the lower atmosphere to the Earth’s surface to the energy reaching the lower atmosphere from the Sun and then subtracts that same level supposedly coming down from TOA. The net increase from this false accounting is 40% of the energy reaching the lower atmosphere or 93 W/m^2.
Think of Venus, surface temperature ~ 500 °C. If ‘back radiation’ is real, it provides 20,246 W/m^2 which reverses and because no energy from the Sun is thermalised in that lower atmosphere it is offset by the back radiation at TOA. This is less than the earth at 153 W/m^2 [ http://www.tak2000.com/data/planets/venus.htm ]
So, instead of 93 W/m*2 extra energy heating the earth’s atmosphere, on Venus it’s 20,093 W/m^2! This is ludicrous as the concept of ‘back radiation’.
MyDog, yes! Have a look at this old thread. Near the bottom I linked a pdf about cloud modelling which discusses an experiment where they flew USAF planes above and below cloud decks simultaneously taking measurements. The discrepancy between theory and reality was around 30W/m^2 IIRC.
I don’t see what is ludicrous about requiring 20KW to maintain a square meter of surface at 500C. A 20 KW commercial furnace can reach 400-500C, and may have a similar surface area internally.
steveta_uk: the 500 °C surface temperature of Venus is from lapse rate warming. As shown by the lower than terrestrial TOA flux, not much heat from the outside is needed to maintain it.
The 20 kW/m^2 on Venus is as imaginary.as the 1/3 kW/m^2 at the Earth’s surface.
And your commercial furnace won’t use 20 kW. The bulk of the power is needed to get fast enough heating, then it’ll go very low depending in the quality of the insulation.
Mydogsgotnonose,
Venus is a terrible comparison with Earth for many, many factors that Venus does not have and Earth does.
If you slowed our planet today to the same speed of Venus, one side of our gases and water would boil off while the other would be frozen solid until it rotated into the sun and boiled off too. This is a single example in many other parameters that are very different.
Hi TB: These aerial measurements looked at the 500 nm signal above and below clouds. The enhanced backscattering by large droplets is very wavelength dependent and is not specular, It can temporarily blind glider pilots.
It’s not anomalous absorption. And it also explains the glory!
Hi Joe: but I am comparing like for like. Thus the climate models assume average insolation and black body lower atmosphere emission. So, in reality, the climate models ARE modelling a Venusian version of Earth, and that I presume was the Plan because Venus was since Sagan, the scare tactic.
Well, time to turn the tables and point out the sheer stupidity of applying the two-stream radiation model to boundaries……
[The extra 93 W/m^2 is presumably offset here there and everywhere by fudges to give just the right projected warming.]
MDGNN, thanks for the reply.
It is indeed interesting, especially your words about surface composition and the evanescent wave:
“The key issue is that in free air there is a given ratio of H2O to CO2 whereas in the liquid phase with optical scattering from the droplet surfaces [depth of evanescent wave controls this], that ratio is controlled by the surface composition.”
I’ve actually made a lot of measurements [too many for my brain to understand yet] of surface compositions [<100nm depth] in aqueous systems using the evanescent wave and surface plasmon resonance-measuring instruments. Using the evanescent wave to excite other molecules [e.g. fluorophores] is also getting more popular in biomolecular spectroscopy and microscopy.
From a chemist's perspective the key point about the surface composition is that essentially "all bets are off" when compared to the bulk solution phase, something most chemists know, yet often forget or underestimate. [Perhaps I should say "almost all bets are off". Mass still has a predictably large effect on surface concentrations.]
Upshot is, that minor components can have major effects at interfaces. Again, no real surprise. The net effects of CO2 chemistry at cloud particles and the ocean? Well, it's hard…
tallbloke says:
June 7, 2012 at 10:35 am
“Brian H: I doubt it. If that was the case, there wouldn’t be several hundred km/h winds howling round slowly revolving Venus busily shifting energy from dayside to nightside.”
tallbloke, the high thin atmosphere performs something called superrotation; rotating several times faster than the planet, always in the same direction. The reason is UNKNOWN says orthodox wikipedia. The entire layer ROTATES around the planet; it is not a simple heat transfer from day to night.
There are Hadley cells, transferring heat from equator to poles in the lower atmosphere; winds near the surface are low.
The temperature of the surface is – due to the GHG, says wikipedia – I would say it as “due to radiative energy distribution by IR scattering” (and convection) – very similar between day and nightside.
I have it from the German version:
http://de.wikipedia.org/wiki/Venus_%28Planet%29
Two possibilities:
a) the orthodox wikipedia warmists agree with Brian
b) Brian has vandalized the German Venus page of the wikipedia with evil skeptic thoughts. 😉
DirkH: what it seems is being developed is a model for the Earth whereby the clouds perform an active role in limiting the GHG warming of the atmosphere whilst at the same time being heated. to give the ‘right’ GHE warming. This and the 200 ppmV limit appears to explain the Miskolczi observation of constant IR optical depth.
They do so by transforming the band-specific radiation from the GHGs into grey body radiation. Thus you see the spectral lines from the clear atmosphere but apparently much less so under low clouds, with similar overall emissivity. [CO2 only is ~0.14 at 200 ppmV at 0 °C, H2O is the rest].
Above the clouds there is no such control mechanism so the tendency is for the GHG ‘photons’ to go into space hence a rapidly falling DOWN emissivity with height.
The other issue is the ice age interglacial bistability. I have written an explanation of this which also explains the 70 year Arctic melt-freeze cycle, now freezing again just as in the 1940s. I shall now revise it in the light of these new hypotheses. GHGs have very little influence. except for second order effects.
To summarise; the clouds give just the right GHG warming in the interglacial and control it to a constant level. When the Milankovitch cycle extends the winters the ocean circulation slows down and you get the ice age. it’s because the phytoplankton can’t control the environment well enough to keep the Antarctic ice melt just right, which they do in the interglacial by controlling cloud albedo in various ways.
[I am looking at a patchwork quilt idea for the oceans whereby trace nutrients are put where they are needed, a revision of Gaia.]
@Michael Hart Whenever you deal with CO2 in chemistry, you are dealing with endothermic processes. As simple as that.
adolfogiurfa says:
June 8, 2012 at 6:29 pm
“@Michael Hart Whenever you deal with CO2 in chemistry, you are dealing with endothermic processes. As simple as that.”
Please elaborate, Adolpho.
Mydogsgotnonose says, June 8, 2012 at 7:45 am:
mkelly: I simplified things by looking at the impedances: zero radiative impedance then zero conductive impedance meaning the 100 W from the first disc is emitted from the second disc’s outward surface.
What these people have forgotten is that Kirchhoff’s law only applies at equilibrium so the emissivity of the inner face of disc 2 is zero. The practical reason is that none of the quantum density of states at the surface can be filled by kinetic energy from the interior so there can be no ‘back radiation’.
Mydog, if your argument is correct this is hugely important because it instantly knocks out all the arguments that Willis Eschenbach, Roy Spencer and others have been using very successfully to justify the existence of back radiation. And they are meant to be skeptics!
Please, please expand on this by explaining this stuff about “quantum states at the inner face of disc 2”. This sounds very similar to Claes Johnson’s theory – but his stuff is completely incomprehensible to most of us whereas you are always clear in your explanations.
I’ve got a nose for things like this and I tell you, this comment of yours (which has kind of passed like ships in the night in this blog trail) is MIGHTILY IMPORTANT. It needs intensive explanation until absolutely everyone understands it clearly. You are the man to do it. It is from such small beginnings that great mountains may be moved.
David Socrates; took me some thinking but here’s my answer:
At the surface of a body is a set of intermediate states [an IR ‘density of states’] at which photons can be absorbed then re-emitted, either to the vacuum or to the interior then to be absorbed and converted to kinetic energy. The reverse process also happens, the transfer of kinetic energy to the intermediate states, which can then decay as before.
The emissivity of a body e is determined by the proportion of such states which are occupied at any time, i.e. the product of the number/unit area [projected for a gas] and the probability of emission per site. The absorptivity a is determined by the proportion of unoccupied states and the probability of absorption per site.
In the case of ‘disc 2’, the assumed infinite thermal conductivity means that the material is very far from thermal equilibrium with the intermediate states so Kirchhoff’s law of Radiation does not apply. Hence the proportion of unoccupied intermediate states is high, a is high and equal to unity in the problem but the proportion of occupied intermediate states is low, so e is low tending to zero in the problem.
The phenomenon of negative luminescence is a practical example: when you pass a current through a semiconductor device which sinks the electrons, its thermal luminescence falls because the electrons and holes created thermally cannot recombine to produce thermal photons.
Concerning the Earth’s atmosphere, we have a similar situation. Assuming there is solely indirect thermalisation, the fall off of pressure with height means that pseudo-scattered energy quanta have a progressively higher probability of escaping to space with height so they can’t recombine, radiative cooling in action. There is no local thermodynamic equilibrium. At TOA, emissivity UP =1, absorptivity UP =1, emissivity DOWN = 0, absorptivity DOWN = 1.
PS Claes Johnson and I are thinking along the same lines. The key issue is that there is only net radiative flux because the energy you measure by a pyrgeometer facing the colder body is the theoretical S-B energy from that body in a vacuum. In reality, take away the pyrgeometer and only the net radiative flux can be converted to heat. Some Physicists imagine that the ‘photon gas’ bounces off filled sites. I suspect the answer is more subtle with direct coupling between the two densities of IR states. This is where Johnson is extending the theory.
PPS Houghton was aware that LTE only holds for the lower atmosphere. What this means is that the probability of direct thermalisation, if it did occur, will fall because it requires a minimum collision frequency to degrade the quantum before the average re-emission time. That gives the same radiative cooling effect, increasing with height so TOA emissivity DOWN tends to zero too. Yet climate science apparently assumes it’s 1!
The earth receives a whole menu of radiations, of the whole spectrum of ENERGY, from X rays to meteorites (these are also energy). This is serious: Nobody seriously considers the transformations of all these wavelengths/frequencies which are converted into heat (IR). Let´s see an example: Corn (Maize) crops transform UV into corn cobs through photosynthesis, which when eaten by humans or animals are partially changed into IR. Thus, though some think that negentropy it is not possible, it is, where food is converted to a higher level energy, of course its “yield” is far from being 100% but it happens….Add to this the EMF energy transformed into heat:
And all the other transformed wavelengths/frequencies. Then the only objective measure is the actual one obtained by instruments (satellites,etc), which indicate, in these times of bad economies 🙂 , as it would be expected, a negative budget.
[mod] alt. image link:
adolfogiurfa: the fast ’90s heating was probably from reduction of Northern cloud albedo by two causes. Firstly the Asian aerosols [the aerosol optical physics in the models is plain wrong as can be seen by looking at any rain cloud], also the aerosols from the phytoplankton blooms in the Arctic.
The latter has caused the same Arctic ice melt as in the 1930s and is a potent source of regional climate change.
As the Arctic freezes, the North Atlantic is cooling:
[From Bob Tisdale]
Our cold winters are the same as in the 1940s. Expect significant cooling soon.
Corrections:
Paragraph 4 of the main post should be “pseudo-scattering to give indirect thermalisation at the walls of the container”.
Paragraph 8 should be “Thus cloud under surfaces will emit specular IR in the atmospheric window”.
[edited, –Tim]
Just had a look at the Nikolov e-mail.
There cannot be any ‘IR down-welling flux’. Its measurement by pyrgeometers is an artefact of the use of a pyrometer shielding radiation from the other direction.
The decreased cooling [at night] from clouds is the result of increased impedance to IR transmission.
Yes this is about attenuation. This does involve a bidirectional energy interchange but is not a problem. at least ought not to be. The lack of recognition of little attenuation under clear sky conditions is typically an issue with agw folks, their darned CO2 is still there.
In addition there is the interception of incoming IR from the sun, widely ignored. I also suspect the thermal capacity of the atmosphere is involved in the whole thing.
This one is so dire there are many teaching university pages out there which have this very wrong, such as solar/light is not heat… that is IR. Ridiculous stuff.
Tchannon: ‘This does involve a bidirectional energy interchange but is not a problem’
It is this which is the core of the problem. The Schwarzchild analysis does what I was taught as a process engineer which is to look at two streams and calculate the difference as the net energy transfer. However because a pyrgeometer is calibrated in W/m^2 not °C, meteorologists actually believe the increased impedance is an energy flow. However, the boundary conditions are wrong.
Just a random thought about CO2 that I am not sure everybody has figured out. At first sight, insulating a planet with a very thin saturated band of absorption seems equivalent to put your swimming suit and add a very thick belt around your waist so you can travel in the snow of Antarctica and feel perfect if the belt is thick enough. Clearly that does not work in the real world. The problem is that heat can randomly move in your body and escape on both sides of the belt.
If we come back to CO2, it happens that CO2 molecules are randomly moving at different speeds. So they absorb and emit with a certain Doppler effect. This means that the frequency of IR is able to randomly move slightly out of the band of absorption. So random movement of molecules might weaken the center of the band.
An other way to look at it. When heat stays in the system, the system has more “order”, when it gets free from the system, it is an increase of “disorder”. It is not surprising for the chaotic movement of molecules to increase “disorder”. I have often read about the widening of the absorption band of CO2 causing more warming, is it possible that this widening might actually limit the greenhouse warming strength of any highly saturated band?
Had a discussion about this yesterday with a warmist who wanted top prove that the above experimental data from Hottell didn’t matter. Band broadening does occur. Some will be Doppler. I don;t know how much though.
However, the key issue is that if direct thermalisation dominates,it doesn’t matter and anyway the climate models exaggerate IR input to the lower atmosphere by at least a factor of 5.
[…] theory disproved a century ago" Here the theory is expanded, partly empirical "Limits on the Co2 Greenhouse Effect" (warning the maths makes my head hurt, so I'll link the empirical bit below) This is a discussion […]
MDGNN or Tallbloke or ?
The APS website explanation of the GHE doubles the radiative surface area & IR flux of the atmosphere in equation 15:
http://www.aps.org/units/fps/newsletters/200807/hafemeister.cfm
Equation 15 balances heat flow in the single layer of air. The left side doubles the infrared flux emitted by Earth’s atmosphere, since IR goes both up into space and down to Earth’s surface, essentially doubling the radiating surface area. This is balanced with IR flux emitted from Earth’s blackbody surface and absorbed by the gray body atmosphere.
2easoTa4 = easTs4 (15)
This seems improper to me, would you agree?
Hi Hockey Stick; this APS calculation is appalling. What they did was to assume a surface emissivity to make the incorrect heat transfer balance.
When I argued the heat transfer with a [Met. Office] modeller, he argued along these lines because ‘It’s the text book answer’. These people are barely educated. The text books always put in the caveat that Kirchhoff’s law only applies at equilibrium and the changeover from mainly convective to radioactive heat transfer to space is as non-equilibrium as you can get.
I’m astonished at how badly basic physics is taught nowadays.
One bit of their calculation wont go down well with the orthodox IPCC’team’ is the number of layers.
Previous calculations have used at least three i.e n = 3
Instead here we have
“n= (Ts/T0)4 – 1 = (287 K/255 K)4 – 1 = 0.6. (19)
It is not surprising that Earth’s atmosphere contains only 60% of an IR layer since O2 and N2 hardly absorb IR, leaving the task of IR absorption to trace amounts of CO2 and H2O. Venus, on the other hand, has a large temperature difference between the upper atmosphere at T0 = 229 K and the surface at Ts = 750 K. These temperatures give 74 IR layers for CO2 rich Venus!”
Further to above.
60% of a layer??
Surely layers must come in whole numbers!
You have all heard the joke about the apprentice who was sent to dig half a hole.
Hockey Schtick
The APS paper cherry picks its assumptions.
The most obvious one is the assumption that if CO2 and water vapour did not radiate/absorb in the infra red there would still be clouds.
There is no physical basis for this assumption.
If we remove this condition but keep the calculation the same we obtain a surface temperature of 272K
That’s half the so called greenhouse effect gone already!
Then there is the point that Joseph Postma makes that 1368W/m2 solar isolation cannot be made equivalent to four times 342W/m2.
That might be OK for the first LoT but quite definitely contradicts the second LoT.
tallbloke;
Those winds are at considerable altitude, in much thinner atmosphere. At the surface only sluggish flows of gas at near-liquid densities occur. Totally irrelevant to thermal transport.