As readers may know, Dr. Roy Spencer and I have had a long running disagreement with the group known as “Principia Scientific International” aka the Sky Dragon Slayers after the title of their book. While I think these people mean well, they tend to ignore real world measurements in favor of self-deduced science. They claim on their web page that “the Greenhouse gas effect is bogus” and thus ignore many measurements of IR absorptivity in the atmosphere which show that it is indeed a real effect. Rational climate skeptics acknowledge that the greenhouse effect exists and functions in Earth’s atmosphere, but that an accelerated greenhouse effect due to increased CO2 emissions doesn’t rise to the level of alarm being portrayed. Yes, there’s an effect, but as recent climate sensitivity studies show, it isn’t as problematic as it is made out to be.
I don’t plan to get into that issue in this thread, as this is an hands-on experiment showing one of the thermal premises of the “slayers” in action to prove or disprove it. Most of what that group does is to spin sciencey sounding theories and pal reviewed papers by a mysterious members-only peer review system, and I have yet to any one of them try to do anything at an experimental/empirical measurement level to back up the sort of claims they make.
What started the recent row was an essay by Dr. Spencer titled Time for the Slayers to Put Up or Shut Up, which I followed on with: The Spencer Challenge to Slayers/Principia.
In their response to Dr. Spencer, they made this essay…
…and in that response was this curious graphic from Dr. Alan Siddons:
To be honest, I laughed when I saw this, because for all their claims to be “experts” on thermodynamics while telling the world that “back radiation” has no effect, this is a clear-cut case of them not knowing what they are talking about when it comes to heat -vs- visible light. Clearly, you can indeed reflect/re-emit a portion of the visible and infrared energy back to the light bulb, energy which would have been lost to the dark surroundings. There is no “extra” energy per se, just a spatial redistribution of energy (a greenhouse atmosphere has higher temperatures near the surface, but lower temperatures at high altitudes). They also seem to fail to understand how a mirror actually works, bold mine:
“Does shining a flashlight at a mirror so that all the radiation comes back to the flashlight make the flashlight shine brighter?”
While the emissivity of a glass mirror is high, no mirror reflects 100%, and mirrors of course are not lossless, so it will also absorb some Visible and IR in addition to reflecting/re-emitting some of it back. You can see this loss of energy in the FLIR camera in the video just before the mirror is removed at about 16:30.
I put their claim of “a light bulb facing a mirror does not heat up” to the experimental test.
I did several spot experiments at home over the last couple of weeks to investigate the issue empirically (since talk is cheap), and to make sure it was repeatable, while discussing the design and results with Dr. Spencer. The first two designs of the experiment had weaknesses that I was not happy with, and so it has take time to devise an experiment in a way that was fully comprehensive and uninterrupted from start to finish. For example, in my first iteration, the experiment was shot from the side (similar to the diagram), but required rotating the bulb mount assembly away from the mirror to get the temperature of the bulb surface. This wasn’t always repeatable to get the same spot on the bulb surface and it introduced variances. Another problem was that standard household bulbs had odd temperature gradients across their surface due to the way the filament is placed. The flood lamp was much more repeatable at its center. Repeatability is important, because I want others to be able to replicate this experiment without significant variances due to the equipment and how it is setup.
After ensuring the experiment works, and is repeatable/replicable, and that the control run without a mirror performed as expected, today in this WUWT-TV segment, I present the entire experiment uninterrupted as one long video. It is almost 21 minutes long, but I had no choice, because at least 16 minutes of it were required to be non interrupted to show the experiment in progress. I didn’t want anyone to be able make silly claims that the experiment was faked that there were video edits going on to change the results, such as Al Gore did in his Climate 101 video.
In my case, I did some graphic overlays to illustrate points and data, but there was no discontinuity edits of the video or audio from start to finish.
Here’s the experiment equipment list and procedure.
Equipment:
- FLIR BCAM portable infrared camera
- 65 watt incandescent flood lamp (used due to mostly flat center target surface)
- clamp on ceramic lamp base and metal electrical base/stand
- small glass wall mirror from K-Mart
- video camera to record the event
Procedure:
- Setup equipment in similar fashion to Alan Siddons figure 3 above, using stands and clamps to allow for correct height and continuous recording of FLIR camera image and a timer image.
- Focus FLIR on flat front surface of 65 watt bulb
- Start video camera to record experiment, simultaneously start digital timer
- Apply AC electrical power to 65 watt bulb
- Note FLIR temperature of bulb center surface at intervals, record that data.
- Run until equilibrium temperature is reached, which I defined would be when temperature no longer increases after a period of about 60 seconds, note that temperature, note how long that takes with timer. Record that data.
- Leaving all equipment in place and operating, place mirror perpendicular to 65 watt bulb surface, at about 3 inches away to fit scale of Alan Siddons Figure 3. This will obscure surface of bulb from FLIR camera but is required so that distance/position between bulb and FLIR is not changed, which could result in altered readings.
- Continue experiment.
- Show with video camera how equipment remains in place.
- Wait for the same amount of time as previous equilibrium temperature took to reach.
- Remove mirror, note on the FLIR camera what the surface temperature of the 65 watt light bulb is at that time.
Premise of the experiment:
If the temperature recorded by the FLIR camera is the same after the mirror has been left in place for the amount of time that it took to reach equilibrium temperature, then the Principia/Slayers claim is true.
If the temperature has risen, it falsifies their premise that “a light bulb facing a mirror does not heat up”.
Video of the experiment (with conclusion) :
Note that this is not a big budget production (it was done in the dining room of my home) so I apologize for less than perfect audio quality. BTW, the clothes iron I used as a prop was not turned on, which is plainly evident in the FLIR image. It just so happend that the tabletop ironing board and iron worked out well to position the mirror…. and I had no budget beyond a few dollars for light bulbs and lamp bases. Where’s that big oil check when we need it? /sarc
Plotted temperature data:
[Note: per a suggestion in comments, this graph was updated to show the data after the “mirror added” as dashed line, since only one datapoint (228F) was measured. – Anthony]
Supplemental information:
In a PDF file here: Slayers_lightbulb_experiment
- Temperature data recorded from the experiment to reach equilibrium temperature
- Graph of the data recorded from the experiment showing data including after removal of mirror.
- I also ran a separate control experiment for 2x of the tested equilibrium temperature time to see if bulb can reach same temperature without mirror. I’m satisfied that the experiment is properly functioning.
I have another experiment planned for part 2 that will test another claim that the Principia/Slayers routinely make. I’ll have that in a few days.
UPDATE: In the claim by Joe Postma at Principia where they stated a couple of days ago that we’d “cut and run” (obviously not, just taking our time to be careful) Alan Siddons makes this claim:
As PSI’s Alan Siddons laments:
“All of us on our side have researched and deeply pondered the actual principles of radiative heat transfer. On the other side, however, the “experts” we argue with, like Spencer, Lindzen, Monckton, Watts, just insist that a body’s radiant energy can be doubled by directing that energy back to it — even though the simplest of experiments will shows that this is false.
I’ve never made a doubling claim like that, nor am I aware that any of the others named have claimed a doubling, only that some energy will be returned, as I have just proven in the “simplest” mirror experiment postulated by Siddons.
I have to think these folks aren’t operating with a full understanding of what the physical basis is when I read things like this. This is an excerpt of this comment left in the thread below by Joe Olson where he confuses a microbolometer with doppler radar:
“Remote read IR thermometers are also used to ‘explain’ this back-radiation warming effect. These instruments work be sending out an IR signal and measuring the shift in the returned signal. ” (bold mine -A)
No, sorry, you are 100% wrong. it is a passive sensing device. No active signal is emitted.
FIGURE 1. One pixel in a microbolometer array. An infrared-absorbing surface is elevated above the substrate and thermally isolated from adjacent pixels. Low mass increases the temperature change from heat absorption. Read-out circuits typically are in the base layer, which may be coated with a reflective material to reflect transmitted IR and increase absorption of the pixel. http://www.laserfocusworld.com/articles/print/volume-48/issue-04/features/microbolometer-arrays-enable-uncooled-infrared-camera.html
Gosh, I didn’t think your misunderstanding of an IR bolometer was that distorted. No wonder you guys make the sort of way out claims you do.
A microbolometer is a specific type of bolometer used as a detector in a thermal camera. It is a grid of vanadium oxide or amorphous silicon heat sensors atop a corresponding grid of silicon. Infrared radiation from a specific range of wavelengths strikes the vanadium oxide and changes its electrical resistance. This resistance change is measured and processed into temperatures which can be represented graphically. Source: http://en.wikipedia.org/wiki/Microbolometer
You should really quit while you can Joe, you are making a fool of yourself when you make such claims that are so easily disproved. – Anthony
UPDATE3: The Principia/Slayers group has posted a hilarious rebuttal here:
http://principia-scientific.org/supportnews/latest-news/210-why-did-anthony-watts-pull-a-bait-and-switch.html
Per my suggestion, they have also enabled comments. You can go discuss it all there. – Anthony
A microbolometer is able to measure infra-red radiation coming from a body that is cooler than itself. In other words the LWIR from a cold body is arriving at the warmer microbolometer sensor and being measured. This, on its own, is enough to disprove the idea that radiation from a cooler body cannot affect a warmer one. These guys really are totally clueless!!!
Its kind of cute for this piece to begin with “we’re not going to argue with the Slayers BUT … here’s all the reasons why they are wrong…”. The slayers are probably going to turn out to be right. WUWT needs to decide how deep a hole they feel like digging for themselves. The political ploy of going along with AGW backradiation theory in order to seem moderate is a Faustian contract that scientifically will get no-one anywhere except further into the wilderness and fiasco of the AGW error. You cant just sweep the second law of thermodynamics under the carpet with some snarky comments and think that puts the issue to rest. Prigogine’s nonlinear thermodynamics of dissipative structures also supports the Slayer’s thesis. Predjudice on this or any other scientific question is not going to change anything.
paulus says:
Why do I get the impression you intend that to be read ironically? I.e. that you are either claiming that no such GCOs exist, or that their obvious nonexistence indicates some kind of mistake in the experiment?
In fact cavemen knew that this effect is real, and they used it: Light a wood fire and try keeping it alight without setting pieces of wood against each other to create a cavern in which the temperature can build. Yes, this combines both air trapment and heat reflection, but it works even when the air flow is fierce, so the heat reflection is significant.
Or consider how much brighter a car headlamp is compared to if it didn’t have a parabolic reflector behind it.
In fact I would go as far as to say that this effect is almost a logical necessity simply by considering the geometry of the case.
In his update, Anthony writes, “I’ve never made a doubling claim like that, nor am I aware that any of the others named have claimed a doubling, only that some energy will be returned, as I have just proven in the “simplest” mirror experiment postulated by Siddons.”
In Willis Eschenbach’s “Steel Greenhouse” articles, assuming black body emitters and a spherical shell insignificantly larger than the actively heated sphere it encloses, the sphere radiates twice as much power with the shell as it does without. This is the optimum case, of course, as the effect of the shell diminishes with distance from the sphere, just as the effect of Anthony’s mirror would decrease with increasing distance from the lamp.
phlogiston says (May 27, 2013 at 7:00 pm): “Predjudice on this or any other scientific question is not going to change anything.”
Exactly. So why haven’t the so-called “slayers” done the definitive experiment that would prove them right and disprove the entire basis of the so-called “greenhouse effect”? They write endlessly, but do nothing. Pretty suspicious, no?
Bob says (May 27, 2013 at 6:31 pm): “Heat was added to the light bulb by back-radiation.”
=======================================================
This conclusion is not supported by the experiment, because reduced convection led to the change in temperature. Whether there was some alleged effect of back radiation too or not can not be concluded, see my comment above.
joeldshore says:
May 27, 2013 at 6:33 pm
…
Or, is it a covert attempt by skeptics to make themselves look good by making it seem that they are not occupying some extreme end of the scientific spectrum but only a middle ground between extremes on both sides, as expressed in posts like this…
——————
Welcome to the wild wild world of nefarious conspiracy ideation Joel! Isn’t it just plain neat?!? 🙂
Careful though. The Great Eye (of Lew) is ever watchful… You might get miscategorized you keep up that sort of thing.
Hey BTW, while you often irritate me beyond all reason when I don’t agree with you (you know, all of those cases where I’m totally right and you’re totally wrong :p ) you did good work over at Roy Spencers in the comments, thanks and kudos.
If the filament became hotter it would shine brighter – it didn’t because heat travels from hot to cold! Redirecting heat to cooler surroundings and measuring this is irrelevant.
There is a fortune to be made if I am wrong. How about an IR receiver that on its bottom side absorbs the 390 W/m2 radiated from the surface of the Earth, and on its top side absorbs the 330 W/m2 (approx) from the atmosphere. That’s 720 W for a one sq m receiver – could run my whole house on a 2 -3 sq meter array (night and day)…….
Greg House says May 27, 2013 at 7:26 pm
Light bulb covered in foil, Greg – what will be ‘your out’ on that (what conditions, what effects will you choose to attempt to void that experiment) ?
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Con spir acy theory much? When it comes to ‘some things’ Joel, there isn’t enough money to make someone (a stooge shall we say) look foolish beyond reason, but Joel D. Shore THINKS he has found that someone: The Slayers. Paid-off by those receiving those Big Oil paychecks to adopt a position BEYOND reason. No, Joel, that kind of darkness requires total commitment on behalf of the ‘oddball’ proponents and adherents, in the face of all manner of logic and ‘demonstration’ (using that word in the ‘old’ sense: a presentation open for examination by all.)
BTW Joel, are you allowed into their site to (“Are you now, or have you ever been a member of … ?“), um, to debate, discuss or dissuade them in their ‘pursuit of total madness’ as you would seem to be attempting to do here almost daily?
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Conditions indeed. One has to careful about the conductivity of the “foil”. I knew a college frat that thought that if he put aluminum foil between his butt and a bottle rocket he would be spared the object lesson. I am sure that he has moved up and on to PSI and their advanced physics program.
Ferdinand Engelbeen May 27, 2013 at 1:51 pm:
rgbatduke May 27, 2013 at 2:14 pm,
It is. The filament is at a really high temperature, like 3000C. So, for the outside of the bulb to go from 80C to 120 C is not a big change. The fact that the glass is only 80C shows how well air convection removes heat from it.
Air will touch every part of the bulb evenly, whereas the foil touches the globe in parts, and would have air pockets in other parts. Yes aluminium is a better physical conductor than glass, but the actual heat conduction may vary depending on how well you put the foil on, how smooth the foil is, etc.
It could also be due to a change in emissivity of the foil compared to the components of the bulb.
Greg,
I don’t think convection is the issue. What has happened is that you have introduced a large (relatively) heat sink/source into the system. Now a light buld has a heat balance between its filament and the local temperature, so if the local temperature is changed by the addition of a very large object, that is absorbing and radiating the lights heat, then the temperature gradient is changed and the filament must raise itself to a higher balanced temperature.
I suspect that you could have a piece of anything of the same thermal mass, and the temperature change would be similar. That is why I suggest reversing the mirror.
Thing is CO2 in the atmosphere DOES NOT add any thermal mass, only one atmospheric substance does that. H2O.
Jim, by wrapping a light buld in foil, you are massively changing its cooling characteristics by interupting radiative, convective and conductive cooling. Why to you think they wrap chill patients in foil, to reduce temperature loos, and let the body build up heat.
Greg House says: “This conclusion is not supported by the experiment, because reduced convection led to the change in temperature.”
Anthony has provided sufficient information for you to duplicate his experiment. Thus feel free to repeat experiment whereby you attempt prove your claim that “reduced convection led to the change in temperature” instead of reflectivity of the mirror.
1) Repeat experiment as defined to closely duplicate Anthony’s results and set a baseline.
2) Repeat experiment using non-reflective (IR thermal transparent) barrier which blocks air movement (reduces convection) in place of mirror.
3) Repeat experiment as defined, except suspend mirror, instead of setting mirror on ironing board so that air can flow past the mirror (convection of air from below mirror, past mirror’s sides, to above mirror).
4) Repeat experiment as described in #3, except use same non-reflective barrier used in #2.
Then report back on results.
Are you Greg House, or has he appointed you power of attorney?
Are you answering for all Dragon Sla yers? You are sounding unusually reasonable (for a change) … but how long is this going to last? How long before Greg comes back in here unsupervised making wild claims again?
We can’t wait …
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richard smith says: May 27, 2013 at 11:08 am
>This test measures the temp of the bulb surface. It does not
>establish that reflecting radiation back to the source (the filament)
>increases the power output of the source. The ghg theory claims
>that downwelling IR causes the source of the IR, the earth’s surface,
>to emit more power – this is what siddons is taking issue with.
I would like to add:
Adding a mirror to a light bulb increases its temperature, not its
*net* power output. (Output of what gets past the mirror.) The mirror
causes the lightbulb to get hotter and produce more heat production
(mostly radiant). Physically-required lack of increase of heat
production is limited to the universe, which includes the shadow of
the mirror.
Something else I want to add: The thermodynamics law requiring
radiative heat transfer from hotter to cooler only applies to *net*
heat flow. When 2 objects thermally radiatively transfer photons
to each other, “the law” only requires *net* heat flow being from
hotter to colder.
When a photon is emitted, its emitter typically does not know the
temperature of what the photon was emitted towards.
When an object absorbs a photon and converts the photon’s
energy to usually heat, the absorbing object usually does not
know the temperature of the photon source.
Radiative heat transfer between 2 objects is a 2-way street. The
famous physics law only requires *net traffic flow* to be from hotter
to colder.
Adding a tollgate to the radiative roadway from Earth’s surface
to outer space *does* make Earth warmer. The thermodynamics
laws only require Earth to be cooler than the sun and warmer than
the face of the edge of the universe. And that my hypothesized
atmospheric tollgate has to be warmer than the edge of the
universe, and cooler than Earth’s surface.
Surely, no laws of physics including thermodynamics say that
you can’t make yourself warmer with blankets or clothes that
are cooler than your body. “The Laws” only require direction
of *net heat flow*. The fundamental laws of thermodynamics
say nothing about speed of heat flow, or “thermal resistance”.
BTW, your answer was not very clear.
Remember, it’s the Slay ers denying (like yourself? I don’t know which camp you’re claiming as ‘home’ ATTM) the effect raised humidity has on a clear night in allowing nighttime temperatures to ‘fall’ more or less depending on that humidity level … you ever take a meteo course? Probably not … a lot of folk ought to avail themselves of a basic course or two and cover these subject before propounding ‘so many things that just aren’t so’ on a regular basis …
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phlogiston says:
May 27, 2013 at 7:00 pm
======
So, we’ve got:
Cute, holes, Faustian contract’s, wilderness and fiasco.
Leading into the big hit, wait for it…..
“Prigogine’s nonlinear thermodynamics of dissipative structures ”
—-
If you have something to say, just say it.
All this dancing around, only distracts.
AndyG55 says:
May 27, 2013 at 8:30 pm
“Thing is CO2 in the atmosphere DOES NOT add any thermal mass…”
http://en.wikipedia.org/wiki/Thermal_mass
(If you have a better definition, please feel free.)
What does that even mean? In the next fragment you say, “…only one atmospheric substance does that. H2O.”. You do understand the vibrational behavior of CO2 and H2O are not that dis-similar? Yes, the concentrations of CO2 vs. H20 (atmospheric) are very different, but you are saying no to one and yes to another when these molecular structures are mostly same regardless if it is the oxygens or hydrogens twitching. These “twitchings” are a great importance to even the oil and gas industry with micro-Raman analysis:
http://en.wikipedia.org/wiki/Raman_spectroscopy
Donald L. Klipstein says (May 27, 2013 at 8:48 pm): “*net* heat flow. … “the law” only requires *net* heat flow being from hotter to colder … emitter typically does not know the temperature of what the photon was emitted towards … Radiative heat transfer between 2 objects is a 2-way street.”
======================================================
“The law” as it has been known historically, does not contain any reference to any “net” thing or “2-way street” or anything like that between a colder and a warmer bodies.
Even on the theoretical level the idea “cold has a warming effect on warm too” leads under certain conditions to an absurd outcome, namely to endless mutual warming without any additional input of energy, and is therefore absurd itself.
Donald L. Klipstein says:
May 27, 2013 at 8:48 pm
Adding a tollgate to the radiative roadway from Earth’s surface to outer space *does* make Earth warmer.
========
You could argue that it makes the earth’s surface warmer. In doing so it must make something else cooler. Otherwise energy has been created out of thin air.
Since the incoming at outgoing energy must be constant at equilibrium, the warming of the surface can only occur if the atmosphere is made cooler.
In the absence of GHG, the atmosphere must be the same temperature as the surface. With GHG that atmosphere must be cooler than the surface, and this cooling of the atmosphere provides additional energy to warm the surface.
Having said this, there is still something fundamentally wrong with the GHG theory, because it predicts that there will be a net warming of the atmosphere – which simply cannot be – because it would require energy to be manufactured from nothing.
This is the reason there is no tropical hotspot, because adding GHG warms the surface by cooling the atmosphere, but gravity limits this cooling because air can only fall so fast, no matter how much it cools.
Thus, no matter how much GHG you add to the atmosphere, once GHG exceeds a critical point, gravity prevents more energy from being extracted from the atmosphere to heat the surface than can be provided by the force of gravity acting on the mass of the atmosphere.
The dry air lapse rate proves that the atmosphere is already at the point where adding more GHG cannot increase the warming of the surface. No matter how much GHG you add, the dry air lapse rate will not increase further.
Sound like MORE nonsense Joseph; from all that you’ve written about you’re mixing ‘night scopes’ and FLIR together in the mind-blender and rendering a near continuous stream of gibberish and misinformation.
Say, you’re not into that ‘free energy’ from magnets and the like are you? You don’t think Maxwell and Roentgen got it all wrong – do you? Maybe best to avoid that topical field in the future, and cut out viewing those YouTube vids on that subject as well …
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richard says: May 27, 2013 at 12:33 pm
>> This happens at the ERL– the effective radiating level. When you
>> increase GHGs you raise the ERL.
>what about the desert at night
Beware of being in a desert at night, especially in a location more
rural than Las Vegas, and especially when the soil is sandy.
The temperature at night in many deserts drops almost like a bomb.
H2O is the biggest greenhouse gas on Earth, and I hope there is
open and honest debate as to how much its presence and effect
changes, in response to increase of CO2.
“Only two things can effect the energy content of any system in a radiative balance. Either a change in the input, or a change in the “residence time” of some aspect of those energies within the system.”
I see all of this as a function of the residence time of the energy involved. So a GHG DECREASES the residence time of energy received via collision from a non GHG, but can, 50% of the time, INCREASE the residence time of outgoing energy received from LWIR from the surface, by directing said energy back towards the surface. So to solve such a riddle we need to know how much of the energy GHGs encounter is conducted / convected, and how much is radiated from the surface. We need to know how much ADDITIONAL conducted energy would exisit in a non GHG world, to make up for the backradiating GHGs. (a lot) And of course the rest of te feedbacks are very complicates, IE how much of the back radiation is converted to evaporation, cloud cover, reflectivit, an accelerated water cycle, greater convection, causing greater amounts of convected molecules to tranfer conducted non GHG enegy to GHG molecules, (cooling) etc.
Clearly, if the GHG cools the portion of energy in the upper atmosphere which contains convective and conducted heat, relative to a non GHG molecule, then conduction from below, as well as convection accelerates to higher elevation. Also, clearly a portion of the atmosphere which intercepts outgoing radiative energy, and keeps a portion of that energy within the atmosphere, causes warming with regard to radiating energy, decreasing convection and conduction from below.
An interesting thought experiment is what would happen in an atmosphere with zero GHG. According to radiation theory the atmosphere would be far cooler (some say 30 degrees) then the surface. However, then the hotter surface would CONTIUALLY NET CONDUCT to the atmosphere just above the surface, the atmosphere just above the surface would then cool by conducting energy to ever higher, and cooler, elevations within the atmosphere, and the lower atmosphere would then continually receive ever more energy via conduction from the surface. Eventually, as energy is never lost, the atmosphere would establish an equilibrium with the surface, the lapse rate would be set via the molecules per sq M with the T established, not by different vibration rates of each molecule, as they would equalize, but by the number of molecules hitting the measuring instrument. (the more mass per m2, the higher the specific heat per m2)
EVENTUALLY, in this non GHG world, you would not have back radiation to the surface, but “back conduction” to the surface, thereby increasing the specific heat above the S-B equation. In a non radiating, equalized with the surface convecting atmosphere, this would occur about 50 percent of the time. Night time cooling would be different in this non GHG world, as the atmosphere would be required to cool via back conduction to the surface, the surface then radiating the heat past the atmosphere to space. Changing the balance of GHG molecules, vs. non GHG molecules likely has a greater affect on WHEN and WHERE (lapse rate) the energy is, then the total energy.
Currrently CO2 molecules may , or may not?, receive more radiatiated energy then convected conducted energy, however this ratio of conducted energy vs radiated energy changes according to the ratio of GHG molecules. A non GHG atmosphere of equall density has almost exclusively conducted convective energy, making up for some or all of the radiative energy. On balance does adding a GHG increase or decrease the residence time of energy verses an atmosphere that must back conduct to the surface in order to cool? I certainly do not know the answer to this.
Please note the word eventually and consider that not all heat sinks fill at the same rate. A GHG atmosphere may heat more rapidly then a non GHG atmosphere, ( where the upwelling LWIR bypasses the atmosphere) yet OVER TIME, conduction and convection work effectively to establish an equilibrium with the surface T.
So this is my assertion, based on David’s Law of physics which reads, “Only two things can effect the energy content of any system in a radiative balance. Either a change in the input, or a change in the “residence time” of some aspect of those energies within the system.”