Greenhouse Thought Experiment

IN = OUT … or … BOOM.
A tweak to the question that explicitly states that we aren’t interested in the instantaneous changes as opposed to the relative values of the differing equilibrium states would seem helpful.

Don’t you mean ‘subtleties’, not ‘subtitles’?
[Fixed, thanks. ~dbs, mod.]

The same amount of heat would be leaving each if they are each in equilibrium. But the distribution of EM frequencies would be slightly different. The CO2 planet would have the EM at slightly higher frequencies.

Ok – had a quick read and tried to get a handle on the basic premise. A bit unfair for a Jan 1st post methinks!
for the first one – it bothers me that there is no mention of transmissivity of radiation through the glass into (or out of, but I’m assuming its irrelevent!) the greenhouse compared to the external plants. The term transparent would imply completely transparent to all radiation (in and out) ? Anyway, I deduce that the thought experiment is basically about thermal convection/conduction restriction within the transparent box? (which of course is the PRIMARY way a greenhouse gets warmer than surrounding (external) air)
On the assumption that transmissivity and reflectivity is meant to be the same for both plants but convection (and conduction) is restricted within the ‘box’ – the plant in the box should indeed appear ‘warmer’ or brighter.
The second experiment describes identical planets at thermal equilibrium but with differing CO2 – but because the second planet is 1C warmer it should reflect that within its EM spectra. Because they are stated as thermally stabilized, and in equal orbits, etc, the radiation in must equal the radiation out but the measured spectra would/should show the 1C surface temp difference. Ergo, I would guess the warmer planet seems ‘brighter’ but the actual temp difference has arisen due to the time lagged equilization of radiation in and out at some time BEFORE the measurement was made and NOT as a result of a difference in radiation in/out between the two planets at the given time of measurement. (in other words, if the measurement was made shortly after the 2x CO2 was introduced on the second planet, it would appear to radiating less (cooler) than the first planet as the atmosphere ‘adjusted’ to equilibrium conditions)
In both cases, radiation in/out equilibrium is supposedly achieved (though the greenhouse box will of course change when the sun goes down!) and this is the critical point. The ‘brightness’ is reflecting only actual temperature (BB radiation curves and all that jazz) differences – not differences in incoming versus outgoing radiation between the objects…
If I am wrong, or missed some subtle point, I am sure its because its Jan 1st and I am hungover! LOL

Kev has missed the point by looking for detail, the two observed systems are the same. Internal temperature is not important to the question, it is a distraction. I think myself that since the systems are at equilibrium, it is not representative of a climate system.

Sean Houlihane says:
January 1, 2011 at 3:16 pm
thanks Sean – I am not 100% sure, but took the clue from this sentence….
<>
from that I took it to mean that the camera is basically a thermal measuring device, which of course, is exactly what BB radiation is all about.
I agree with your comment regarding a climate system – though I presume that the premise is that so long as radiation in/out isn’t changing significantly, the climate system is irrelevant?

In the greenhouse the temperature will be slightly higher but not because of greenhouse gases but because of suppression of convection. That’s how greenhouses warm
In the second planetary case there is no suppression of convection, just a very slight increase in nighttime temperatures due to a slight reduction in thermal losses.
Ergo, the difference due to greenhouse gases would be lost in the natural oscillation of the atmosphere.

HankHenry says:
“My question is: what would happen if on these twin earths the normal one had 1 atmosphere but the other had 50 times normal atmosphere?”
Well, scattering would certainly be very different, since any transmission path would be through a much greater density of atmosphere.

This should be fun to follow. Personally I agree with John Robertson above. Glass is a physical barrier and it changes things. Think of glass 2 molecules thick versus a half meter thick. The planets, on the other hand, are exposed to space. It doesn’t matter if one is warmer than the other, they will balance as energy in = energy out.

The interior of the greenhouse is warmer not because the glass or whatever traps the radiation, but it is warmer because you do not have convection. In free air, the warm air will rise and be replaced by cooler air from higher altitudes. You can perform this experiment easily with your car. Take your car (when its warm enough, right now it is not so in Boston) and roll up the windows. Leave it in the sun. Then measure the temperature of the interior using one of the remove sensing IR thermometers you can obtain for not a lot of money. You are measuring the quantity of outgoing IR, which is how those operate. Now do the same with the windows of the car open. You will measure a much lower temperature since the convection currents of air out of the car will carry the heat away and replace it with cooler air.

David,
I don’t think the camera would show equilibrium, because the warm greenhouse would still be transfering much of the excess heat by convection along the outside walls, and thermal cameras only record radiation, not conduction and convection.
This might be a flaw in the thought experiment, because such cameras would tell us that Venus is a fairly cool planet since they see cloud tops.

The effective height from which thermal radiation leaves the higher concentration planet will a bit greater than that of the lower concentration planet, so its radiating surface will be somewhat greater. Therefore, in order to radiate equally, its brightness (radiating temperature) must be slightly less. Extrapolating downward to the earth’s surface from the effective height of radiation, at the adiabatic lapse rate, the surface temperature of the higher concentration planet will be somewhat higher because of the greater height through which adiabatic convection must extend. Presumably both planets will reflect sunlight equally at wavelengths that do not interact with the greenhouse gases.

alcuin says:
January 1, 2011 at 4:27 pm
The effective height from which thermal radiation leaves the higher concentration planet will a bit greater than that of the lower concentration planet….
sorry, but why?
the concentration of CO2 in the atmosphere is described as doubled – but there is no mention of any increase in atmospheric depth (all other conditions are described as identical)?

Let us consider the two planets, and just for simplification, suppose that both atmospheres are completely transparent at all wavelengths — except for the CO2 absorption lines. For this scenario, all of the green house effect is due to the CO2. Since both planets are in thermal equilibrium, each must radiate (or reflect back due to albedo) the same total energy out as is incoming. For two identical objects at differing temperatures, the warmer object will radiate more at every wavelength, and will also have a maximum at a slightly shorter wavelength. Of course, these two objects are not identical. One has more CO2 and is at a higher temperature — and yet we know that both radiate the same total energy out. Since we have posited all other, non CO2 gases as transparent, there is only one way to modify the radiation curve for the warmer object so that total area under the curve equals that of the cooler object. The radiation out from the warmer object must have a stronger dip at the wavelengths where CO2 absorbs. After all, the CO2 (in this scenario) is the only thing in the atmosphere which is not completely transparent.
Is this reasonable? Aren’t good absorbers also good emitters? Won’t the CO2 mixed into the upper atmosphere be radiating outward? Why don’t we see a spike in radiation at the CO2 lines? And if we did, then doesn’t that makes an energy imbalance. I know that the green house gas effect is well accepted by almost everyone, so will someone point out the flaw in my reasoning, at least as it pertains to this simplified model?

I at once suspected this “thought experiment” had everything to do with a mythical beast called “The Greenhouse Effect” and accordingly I therefore opted in both cases to vote where it said “The same”
If I am wrong then I shall, be very happy as no doubt I can then look forward to an explanation for “The Greenhouse Effect”. I mean an explanation that: a) makes sense, and b) Does not prove the complete opposite. (All explanations I have read so far, fall into the ‘No sensible explanation ‘)
I feel certain that if a “Greenhouse effect” natural, forced or otherwise exists then there MUST be somebody out there who can explain it, calmly and rationally.
The usual; “The greenhouse effect is natural, is well understood by scientists bla – bla -bla –” does not cut it and cannot be seen as scientific proof one way or the other. Nor can opinions of how it may be happening, nor do opinions of those who have more opinions than others.
By the way:
Why not make it a project for say 2011’s first couple of months: Write your own essay explaining “The Greenhouse Effect” and poste it on WUWT.
It could become interesting reading!

As a founding member of People Against Acronyms and Abbreviations or PAA&A, I had no idea what IOW meant. My first thought was that IOW meant “I own won”. There was a paranthetical phrase with a missing comma as in “I own won, a cool toy which…” Then I find Id-ian physics. I am beflummoxed, my temper-ature is rising. Maybe it is a typo and should be Ind-ian physics. Well, I did look up IOW and determined a good translation is “In other words”. I did not get anywhere with Id-ian physics. Maybe it’s Idaho-ian physics. Or maybe better yet, Intelligent Design-ian physics.
Willis Eschenbach had a good discussion of CO2 and radiation in People Living in Glass Planets.

Doesn’t everyone here get it?
I assume most if not all of you are sitting in a room. Objects in that room are all at the same temperature, black or white. All of the objects are in resonance radiantly with the walls and each object affecting each other object much as gravity. Some would propose (AGW proponents) that if your room was evacuated without convection and conduction that the black objects (think co2) would be warmer temperature wise than the white objects (low absorptivity and emissivity) but I for one don’t buy that unless someone can concretely prove it to me, by physics.
Is it any difference with the Earth just because it is only warmed on one side every 12 hours? If there was no sun but a diffuse radiation on every side of equal radiation (TSI) would that not be the same except for the diurnal up and down of the temperatures and seasonal variance? In that case it would be the same as your evacuated room, the same? Any thoughts at all or is this just politics on both sides, to hell with the actual physics and science?
Sorry, sometimes I think NObody is thinking. Just the same dribble.

An object with “less escaping thermal radiation” is warmer, not cooler.
The image seen by the camera is cooler in that case because fewer photons are reaching the “film” or retina; but the camera’s film is not the object.

1) Thanks Jeff for posting this, you hit my sore point.
2) My dream for the day would be that by the end of this thread, even if 2000 comments long we would be able to answer the question — Does Kirchhoff’s law (emissivity and absorptivity, directly co2 related for it absorbs more) apply to Earth as other normal matter as view from afar like the moon. That would be an actual accomplishment scientifically here on wuwt. So many, maybe even myself, seem confused.
To me the increased emission equals the equally increased absorption and since in = out there is NO affect from co2. Maybe even getting back into Venus’s atmosphere later for it seems to show why this is so. Think lapse rate.

If tomorrow is clear, I will perform this experiment with my rustbucket Toyota Tercel and report back.

For the first experiment none are correct.
If I assume the camera is outside the box then the camera will most likely see the box and not the plant inside.

The temperature of the plant is approximately a function of
(a) air temperature and
(b) transpiration.
All things being crudely equal, the plant in the greenhouse will register a higher temperature, since imposing limits on convection will increase both air temperature and humidity, reducing transpiration and the evaporative cooling effect this has on the plant, particularly its leaves.
Increasing wind speed and lowering humidity could reduce the temperature of the plant inside the greenhouse by increasing transpiration, despite a rise in air temperature.
Conversely, increasing the amount of CO2 available to the outdoor plant could increase its average temperature with no apparent increase in air temperature. This is because CO2-enriched plants don’t have to struggle so hard to breathe: stomata close in response to elevated CO2, reducing transpiration, meaning less evaporative cooling and water consumption.

“William Sears says:
January 1, 2011 at 6:10 pm
Without knowing the emissivity your camera can not give a temperature reading from the integrated intensity. In both cases, at equilibrium, the radiant energy in will be equal to the radiant energy out. I assume that we are ignoring convection and conductivity, although that may not be a safe assumption with the glass greenhouse. The two cases can be at different temperatures for the same radiant intensity, because they will have different emissivities. This is the essence of the Earth’s Greenhouse effect.”
I think you are exactly correct in the first statement but wrong in the second. Is this not why black objects in an IR camera show as bright and white objects (of anything with low absorption) show as dark. How can this be if their temperature is the same? It’s that the bright objects are absorbing more but equally emitting more, Kirchhoff’s law and the opposite for lighter colored objects or i.e. objects of less emissivity. Now apply that to co2 which absorbs more. To temperature it doesn’t matter, it emits more to space therefore preventing any warming, it has to.
In the second statement you are wrong, you said “The two cases can be at different temperatures for the same radiant intensity, because they will have different emissivities.”. If the have different emissivities they also have different absorptivities and the effects equate and the temperatures MUST BE EQUAL in a given radiative field (in the same room).
If speaking of inter-atmosphere effects instead of measurements from afar outside the object it gets more complicated.

”earth’s land and ocean surface warmed to an average of 14c”…
the graphic seems to indicate that the sun warms the earth’s surface to an average of 14c?
those rescued chilean miners might beg to differ. it was not 90 degrees fahrenheit in that mine not because the sun warmed 390 ppm of CO2 and an inch of soil half a mile above their heads for a few hours a day. it was hot because they were closer to the source of heat.
i’m always amazed that scientists want to completely ignore the overwhelming mass of earth and the incomprehensible amount of btu’s it contains to entertain the thought that a trace gas in the comparatively negligent mass of our thin atmosphere is somehow going to overheat the entire planet with solar radiation that is normal to its surface for, at best, an hour a day.
have we all gone mad?
it’s not a coincidence that the mean annual temperature of air at the surface miraculously matches the temperature of the soil a few inches beneath the surface. if the temperature of our air is increasing, maybe we should first wonder what’s going on under our feet? and if it isn’t land use change, we shouldn’t be so quick to assume that a hair at the end of a dog’s tail is going to wag the whole dog.
maybe these global warming scientists should try warming their tea by heating the air above it? perhaps when they realize that they have to heat the same volume of air above their tea to 800 degrees or so in order to warm their tea by 1 degree, that then they will reconsider AGW?
we deforest, pave, build, convert matter to energy, and redistribute heat and energy all over our earth. we should be pleased that our thermometers tell us we’ve changed our environment by less than a degree, if at all.
michael mann should have been very curious when his tree rings told him things may actually be getting colder – he may have stumbled onto something that we should really be worried about.

Kev-in-UK asks why the effective height of radiation is higher when the concentration of greenhouse gas is greater. The effective height of radiation from an atmosphere is conventionally taken to be that altitude at which the optical depth becomes unity, as integrated over height from outside the atmosphere. If the concentration of greenhouse gases are doubled, their opacities are also doubled at each level, so the integral becomes unity over a shorter distance down in the atmosphere, i.e., at a greater height. Of course the opacity = (1 – transmissivity) varies with wavelength, so a lot of averaging is involved, but the use of an effective height in this manner is the way that the radius of the solar photosphere is defined. Outward radiation from lower altitudes tends to be absorbed and reradiated at higher altitudes.

This is the problem with talking about “global mean temperature”. Because there is day and night, each location has outgoing radiation that continuously varies. If the temperature in the greenhouse is warmer, it will radiate more. In the planet example, the high CO2 planet receives less radiation at the surface, as the sun’s radiation is about 45% in the infrared. In this example, it starts at dawn more than 1 degree warmer, and heats slower than the low CO2 planet, but after sunset, also cools slower than the low CO2 planet. On Earth, due to convection, peak surface temperature occurs around 2pm.
Net-net, the 2pm radiation from orbit should be about the same, as some of the higher surface temperature gets absorbed by the CO2; otherwise, the surface temperature wouldn’t be higher. At some times of day, radiation out observed will differ, unless the high CO2 planet keeps always 1 degree warmer than the low CO2 planet, in which case the radiation out would also always be the same. Lower radiation from the high CO2 planet from 2pm to 6am (cools slower). Higher radiation from 6am to 2pm (warms slower). Early afternoon, about the same.

Many above are speaking, of the two planet experiment, maybe without knowing it, in blackbody terms (unrealistic) and forgetting the emissivity for the Stefan-Boltzmann realtion in a more realistic example. Blackbody is very theorlogical whereas a gray body is close to reality, especially if viewed as the sum across all frequencies. Black body uses E = σT^4 where as gray body includes the emissivity of the surfaces as E = εσT^4 with “ε” being the emissivity that you can lookup for a rough estimate for many subtances and surfaces. Just the fact that one planet is 1°C warmer does not immediately imply it emits more without taking into account the planets emmissivity as a whole.
However, in the example given above the warmer planet had more co2 which would increase its emmisivity AND equal absorptivity, and vise versa, in comparson to the other planet which would mean it would be radiating much more that the cooler planet that just the one degree difference implies but it equally would be absorbing more and of an equal amount. The 1 deg difference would not occur in reality, that is a great example of the AGW fallacy.
Like Dr. Feynman said of Q.E.D., it twists your mind a bit, sometime a lot, but that is the way physics is IN REALITY and there is nothing we can do but try to understand it properly and not to twist reality into something that isn’t.

“In the second experiment, the two planets again have the same thermal emission temperature. In planet 1, with the doubled CO2, the layer that thermal emission temperature occurs is 460 metres higher than planet 2 and hence the surface temperature on planet 1 is 1.0C higher. Effectively, the lagtime in which the energy enters and then exits planet 1 is a few minutes longer than planet 2. 44.06 hours in planet 1 compared to 43.44 hours in planet 2.”
nice bill.

For our second experiment we have two thermally stabilized earths, one which has today’s CO2 and one which has 2X today’s level. All other conditions are identical and for some quirk of Id-ian physics, they orbit one right behind the other around the sun such that we can observe them simultaneously on our fancy camera.
I say no change. Both will absorb the same level of upwelling LWIR from the surface. The 2X planet will achieve its quota at a slightly LOWER level. Both planets will experience the SAME quantity of energy being conducted into the atmosphere via molecular collisions. Both planets will handle the absorbed energy through the lapse rate up the atmosphere.
Areas of the tropics experience much more than a doubling of H2O without any dramatic rise in temperature. In fact seasonal temperature change over the tropic oceans is far more stable than seasonal temperature changes over desert regions.

Kev-in-UK says:
January 1, 2011 at 4:44 pm
———
alcuin says:
January 1, 2011 at 4:27 pm
The effective height from which thermal radiation leaves the higher concentration planet will a bit greater than that of the lower concentration planet….
sorry, but why?
the concentration of CO2 in the atmosphere is described as doubled – but there is no mention of any increase in atmospheric depth (all other conditions are described as identical)?
———
The atmospheric depth has not increased but the optical depth at CO2 absorption wavelengths has.
Warning! I am using optical depth as absorption depth. Some specialities use a reversed definition of optical depth

alcuin says:
January 1, 2011 at 9:47 pm
Sorry, – I meant, why in this case? – the planets are supposed to be identical in all aspects apart from the Co2 conc. This is presented as an ‘ideal’ situation with all other equal properties, so I am assuming the atmospheric ‘envelope’ is the same (density, mass, depth, etc).

Jeremy says:
January 1, 2011 at 5:01 pm
Assuming the glass is totally transparent (to all EM radiation) then the trapped air in the box and by consequence the plant itself will be at a higher temperature due to no cooling from convection.
Therefore the plant in the box must be hotter and therefore it must emit more blackbody thermal radiation which will be seen by the camera.
Ah, but would it actually be “seen by the camera?” Imagine two people sleeping on separate beds in a room. One is lying on top of the bed, the other is under a duvet. The one on top is comfortable and cool, the one under the duvet is sweating from the warmth. But which one do you think would look brightest to a heat-sensitive camera looking down on the two beds?
Answer: the head of the person who is sweating under the duvet.
Think about it. {/joking}

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.” The longer the “residence time” the greater the energy sink capacity. The greater the energy capacity, the longer it takes for any change to manifest. Convection shortens the residence time of energy within a system.

Add: surface temperature change.

And for those who use the argument “energy in should be energy out”, note that radiant energy changes frequencies interacting with matter and the camera measures infrared only.

Jeff Condon. Sorry to say but as the Greenhouse effect is IMPOSSIBLE under the laws of physics- particularly thermodynamics. It is like expecting water to run uphill. Yes, with a pump (work put into the system) but not possible in the real world. Heat ALWAYS moves from a hot body to a cooler body and this also applies when radiation is the transmission medium as well. Those who try to claim otherwise either never studied a physical science degree or have forgotten the relevant lectures in their chemistry or physics degree.
Therefore your post and questions are totally irrelevant to the question of climate and climate change.

Making a few assumptions. “Greenhouse” implies that the enclosure is differentially transparent to incoming and outgoing radiation. “Transparent” means it does not reflect all incoming radiation. For the plants I assume“Early afternoon” means the phenomenon is cyclical.
For the planets the problem is different, the camera would integrate, not just across all wavelengths but across all daylight hours because it would see all the daylight hours simultaneously, it is not cyclical.
Plants.
The camera is taking an instantaneous measurement during the course of a cycle.
If the phenomenon is cyclical then instantaneous equilibrium is never reached. Over a number of cycles cyclical equilibrium will eventually be reached – once the system has warmed. Part of the incoming radiation will cause a state change within the system and the energy used to achieve state change is latent, not directly apparent to the observer Whilst it’s warming the system emits less radiation than when it’s warmed because its storing some of it in the form of state change. During that part of the cycle it may appear dimmer in two senses – it’s light temperature is “cooler”, and the amount of outgoing radiation is less, but as energy is added to the system it warms up and the light temperature will brighten to a point where it it is the same as the other system,and then become brighter in terms of light temperature, however it will still be emit less less radiation until it reaches it peak brightness at equilibrium. I believe “brightness”here is intended in the quantitative, sense.
Since it is cyclical, of course, it never reaches instantaneous equilibrium. There is a shift in phase and amplitude (time and quantity) applied to the Greenhouse plant However, twice within each cycle it will achieve a faux equilibrium, in the way a stopped clock tells the right time twice a day. At first the faux equilibria will occur at different times for the greenhouse and non-greenhouse plants, but as the non-reversible state changes are completed by storage of incoming radiation the faux equilibria will be resynchronised. Whist they are in disequilibrium, as Derek says, in the early afternoon the greenhouse plant will be warmer and brighter. But necessarily, during the course of the early afternoon it will also have been dimmer and of equal brightness. It all depends on what you mean by “early” and also how long the experiment has been running.
Planets.
The camera is not taking an instantaneous picture, it is recording a total over all daylight hours. It’s given that the planets are “thermally stabilised” – there are no further irreversible state changes taking place – faux equilibria will be synchronous – and the radiative cycle for both will be in phase. The quantity of radiation from both at all times of day will be the same and will be equal to incoming radiation. The camera will see identical quantities of radiation from bodies which have different colour temperatures, they will appear equally bright.

anna v says:
January 2, 2011 at 3:55 am
…the camera measures infrared…
According to the question, the camera is a cool toy which in this case happens to detect all EM wavelengths with perfect sensitivity. To be clear, the camera integrates to measure the radiative emission temperature of the object.
Seems you have missed the point of the thought experiment, which is to avoid complicating the understanding of the class with real-world complexities. You may be correct in the real world, but you have not helped to clarify that energy balance is the first step necessary for understanding. Almost everyone is jumping in to this question at the wrong point…

“For our experiment assume we have a bolometric camera for measuring emitted thermal radiation as an image. IOW a cool toy which in this case happens to detect all EM wavelengths with perfect sensitivity.”
No other variables are provided or measured, therefore none can be assumed. Both images will look the same. “all EM wavelengths with perfect sensitivity” This is the null hypothesis. However if the images are not the same, then you have a basis for “grants for life”.

For clarity I will post my original simile that Jeff Id refers to.
It can be found in the comments on this thread at Jeff’s blog, the Air Vent.
http://noconsensus.wordpress.com/2010/12/19/fixing-the-basic-agw-calculations/#comment-44043
I wrote there,
” Question, have you ever looked at a thermal camera picture of a greenhouse and it’s surroundings. ?
The greenhouse will be warmer than it’s surroundings, so it will be a brighter image than it’s surroundings.
AGW “theory” says the greenhouse is warmer because it traps radiation,
YET the thermal image will clearly show beyond doubt that the greenhouse IS radiating MORE than it’s surroundings
(with the same solar input).
What does this show. ?
It shows whatever is cooling the surroundings is far more powerful than radiation, AND
that it is not radiation doing most of the cooling (otherwise the higher radiating greenhouse would be cooler than it’s surroundings).
If one opened the doors and windows in the greenhouse, especially on a breezy day,
the greenhouse would soon reduce it’s temperature to that of it’s surroundings.
Logically the temperature difference was removed from the greenhouse to the surroundings or aloft by air.
Air transporting sensible, and latent heat (of water vapourisation), I would suggest.
When the doors and windows are closed it logically follows that the increase in temperature inside the greenhouse is due to
the reduced transport of sensible and latent heat (of water vapourisation) from inside the greenhouse to the surroundings.
Obviously even with the doors and windows of the greenhouse are shut,
some conduction and convection at the greenhouse glass surfaces occurs, and
this explains why a greenhouse remains warmer than it’s surroundings for some time after sunset.
Hopefully this has illustrated that a greenhouse works by reducing conduction and convection,
NOT by “trapping” radiation, as AGW pseudo climate science, “physics”, and “theory” suggest. ”
The pdf that my simile came from can also be found at the GWS forum on this thread.
http://www.globalwarmingskeptics.info/forums/thread-1028.html
yours,
Derek.

Since the greenhouse effect clearly works for greenhouses ( nothing to do with C02 of course) the plant in the greenhouse will be hotter so if ( big if) this clever camera is measuring plant temperature it will measure it as hotter by detecting a different spectrum of energy and more energy. However I doubt this is the real thought experiment proposed.. please clarify Jeff.

Jeff,
This was a poorly worded thought experiment – you describe your bolometric camera as measuring “thermal” radiation rather than the entire spectrum of energy.
Those who took your words at face value and assumed you were talking about measurement of emitted “thermal energy” will have a different answer from your final answer above.

John of Kent says:
January 2, 2011 at 4:30 am
“Heat ALWAYS moves from a hot body to a cooler body and this also applies when radiation is the transmission medium as well”
This is the ‘simplified’ explanation which works for most things and is taught quite widely.
At the molecular level heat is radiated equally in all directions.
The reason heat moves from hot to cold is that colder objects are radiating less heat in all directions then the warmer objects.
As a simple thought experiment
Put two rotary sprinklers on either end of your yard.
Attach a fire hose to one and a garden hose to the other.
Both rotary sprinklers are pumping out water equally in all directions.
Which way does the water flow?
Observing the flow of mud we’ve just created in our back yard, the water(heat) is flowing from the fire hose side to the garden hose side.
But a close examination of the garden hose sprinkler shows it is spraying water equally in all directions and some of that water is ending up on the fire hose side.
Of course CO2 molecules aren’t connected to the water mains, so to further our thought experiment we replace the sprinkler on the garden hose side with a baby pool.
Eventually the baby pool fills up with water and the water overflows the sides of the pool equally in all directions, some of it flowing back towards the fire hose sprinkler and some flowing out into our neighbors yard.
So called ‘green house gases’ are basically baby pools. They absorb IR energy and then overflow in all directions equally.

Wayne says:
Jan 1, 2011 at 7:23 pm
“Is this not why black objects in an IR camera show as bright and white objects (of anything with low absorption) show as dark. How can this be if their temperature is the same?”
I don’t know what this refers to since I never made any such statement. If anything, it is the exact opposite to what I said. Also, an infrared camera will only measure a fraction of the e/m spectrum. It is not the perfect device given in the thought experiment and is therefore sensitive to spectral shifts caused by either temperature changes or the wavelength dependence of the emissivity.
“In the second statement you are wrong, you said “The two cases can be at different temperatures for the same radiant intensity, because they will have different emissivities.”. If the have different emissivities they also have different absorptivities and the effects equate and the temperatures MUST BE EQUAL in a given radiative field (in the same room).”
Again, this does not address my statement, which refers to the thought experiment given. In a closed room, at thermal equilibrium, you are correct. But, in the present case the sun is the source of illumination and the objects are in equilibrium with all their surroundings, not just the sun’s surface. However, I thank you for your comments. I could have expressed myself more clearly.

Jeff, you can’t throw excluded constraints in at the explanation phase and have a consistent response. Unknowns that impact the results should be in the list of constraints of the experiment in the beginning, not in the answer you just happen to select.
Pretty lame if you ask me (and one of the reasons I didn’t bother with this “thought experiment–I got to the end and had a sense that all was not complete.)

RockyRoad:

Pretty lame if you ask me (and one of the reasons I didn’t bother with this “thought experiment–I got to the end and had a sense that all was not complete.)

It’s always great to see people respond to fun little exercises in the spirit of comity in which they were posed. 😉

“Increasing/decreasing incoming energy by itself shouldn’t change the emission altitude.”
Wrong! Tell that to the thermosphere or rather Diurnal atmospheric bulge which tracks the solar point around the Earth bulging up to an altitude of 600 km at noon and disappearing back below the mesosphere at night.
“The resident time in the atmosphere for the incoming energy won’t change so the altitude won’t change.”
So if I boil a kettle for long enough the water will exceed 100º C will it?
Really Jeff that is sloppy stuff.
“If you change the absorptivity of the atmosphere (particularly in the long wave regions of the spectrum)”
You will also increase the emission. For every action there is a reaction. I have already pointed this out but as with all proponents of the “Greenhouse Effect” you appear to suffer from selective reading.
“the energy stays resident in the lower atmosphere for a longer time on average before re-emission. “
Not if the emission increases with the absorption, which it does according to Kirchhoffs Law. We are talking about radiation at light speed here Jeff.
“This results in the average emission altitude increasing yet the same amount of energy being emitted from the body.”
Does it? How?

Yes, I agree with DeWitt’s evaluation of the situation. With regard to the practical problem of observing the difference, such considerations did not seem to affect other aspects of the proposed camera; the goal, as I understood it, was to tie down the principles involved. The point is that the radiating surface at the TOA of the 2x CO2 planet would be cooler, not warmer.

Jeff Id says:
January 2, 2011 at 12:03 pm
alcuin,
DeWitt estimated the effect you describe at tAV. It is one of those minor things I mentioned above.
“Nope. The luminosity is the same. For 2x CO2 the total power will be spread out over a slightly larger surface area so it will be slightly dimmer, not brighter. And an increase in effective altitude of 150 m (Tsurf + 1 C at a lapse rate of ~6.5 K/km) changes the surface area by 0.005%. If planet 1 radiates 240 W/m2 then planet 2 radiates 239.9889235 W/m2 and Teff is lower by 0.003 K. Good luck measuring that.”
I was not aware that gases formed and presented two dimensional heat emitting surfaces around objects such as planets.
A 150 m increase in effective emission altitude would be 150 cubic meters not square meters. Looks like someone should take another look at their numbers.
Gases emit in three dimensions not two.

Jeff, your views make sense

Mike D says, January 2, 2011 at 9:14 am:
“It is stunning to me that the “warmer in the greenhouse” answer in poll question #1 did not get 100% agreement. Maybe I read the question wrong, but I have reread it numerous times.
For your next poll you should ask this crowd whether the Pope is Catholic or not, or where do they think bears defecate.”
======================================
The info I read was as follows:
“We have two plants, one is contained in a transparent box (greenhouse) the other in open air, both thermally stable (temperature isn’t changing). We take an image of the two plants in the early afternoon on our fancy camera, what do you find in the image?”
Please note that the two plants are both thermally stable (temperature isn’t changing). The best place I can think of where a plant can be thermally stable with unchanging temperature late in the afternoon whilst inside a green house in the Northern Hemisphere is north of the polar circle, say at this time of the year. Both the plant inside and the one outside will be frozen stiff of course but they will still radiate equally (the same) in the IR spectrum. The curious thing here is that there is no sunshine providing shortwave radiation. But as we all know anything with a temperature above absolute zero (0 °K) must radiate –etcetera, etcetera.
As for answers to what seems to interrest you at the moment:
It is great possibility that the pope is Catholic, but he could of course be an atheist. Only he knows. Where bears defecate depends greatly on where they are at the time but generally brown- and grizzly bears do it mostly in the forest whilst polar bears may decide to fertilize a couple of plants whether inside or outside of any green house erected in their Arctic habitat.
Now then, which type of bear did you have in mind?

I didn’t read all the comments, so forgive me if this has been coveremy comments are repetitive.
The thought experiments make perfect sense, given the assumptions; i.e., that other variables, like clouds and increased evaporation, aren’t involved. The problem with the examples is that they have nothing to do with the real world.
This recent post does a good job explaining the problem with thought experiments that don’t deal with all the relevant variables: http://wattsupwiththat.com/2010/12/28/simple-physics-in-reality-my-feather-blew-up-into-a-tree/#more-30345
Willis Eschenbach has some great comments sabout non-linearity somewhere on this site which also speak to this issue.

Ok Jeff Id, I know the happenings in the “Greenhouse theory” are different to what happens in a real green house. If the “Greenhouse theory” is a misnomer then that is because it has gone through some modernizations and alterations (as the science has changed) since it was first thought up and named way back in the early 19th century. What I would like to know is:
1) How can 99% of the Atmosphere be warmed by long wave “back radiation” from a trace gas when Nitrogen, Oxygen and argon are all transparent to the stuff?
2) Is it not more likely that since the “bottom” of the Atmosphere and the “top” of the Earth’s surface are in contact with each other – at all points – heat transfer is taking place first by conduction then convection (evaporation) rather than radiation?
3) Why is it warmer over the top of – than it is below a flame? If heat is radiated should the temperature not be distributed equally in all directions? If it is warmer above the flame does that not point to the fact that convection is a much better form of energy transport than radiation?
4) Why is “back radiation” always depicted as being “one directional” only? (The full force, say 333 W/m² is always pointed towards the surface but there must also be 333 W/m² emitted in all other directions i.e. towards space)
5) How do “Greenhouse gases” stop or delay convection or radiation in order to warm the Atmosphere or as it is called “trap heat”?
6) And lastly – for now – How can radiation which is an energy transport system warm the planet any more than conduction or convection can?
Let the “Greenhouse Theory” go and consider instead the fact that air movements on this planet are mainly horizontal and for that reason alone adiabatic cooling (and warming) take a lot longer than if they were vertical.

You appear to forget biotic mineralization on your two planets. Plants use photons to fix carbon and excrete IR. The end of plant life is either recycling or mineralization. Mineralization is also there as plants enter the soil and are converted to coal.methane or in the oceans becoming oil/methane.
The amount of mineralization, or ‘bottled sunshine’, is proportional to biotic productivity, which is dependent on plant growth conditions. All thing being equal, plants grown in high CO2 will grow faster, grow in more marginal niches and be a better source of mineralization. So the planet with with more CO2 will have more plant life, have more complex biomaterial (which is just another form of informatio) and so will emit less energy.

Jeff Id says:
January 2, 2011 at 12:49 pm
michael hammer says:
January 2, 2011 at 12:20 pm
I left an explanation of why it happens for will. The mean path length and probability of photons being absorbed changes. The probability of escape for each emitted photon in a higher CO2 atmosphere goes down causing the mean emission altitude to shift to a higher position in the atmosphere. The whole warming effect is just this delay in the power flow from absorption to emission causing an energy buildup.
I don’t really enjoy talking much about it because people then assume I’m a big supporter of AGW extremism. I am not, but the basics are real.
##########
jeff the thing that astounds me is this. people have a choice.
1. accept the basics and focus on all the uncertainty WITHIN climate science.
2. deny the basics and get pwnd in any technical discussion of the basics.

There is no need for thought experiments here, we already have detailed pressure and temperature data for two real planets with greatly differing concentrations of atmospheric carbon dioxide: Venus and Earth. And that data shows that, over the range of pressures in the Earth atmosphere, there is no difference due to their difference in carbon dioxide. There is no “greenhouse effect” at all, in either atmosphere:
Venus: No Greenhouse Effect

Sorry, that link has a missing colon; the proper link is:
Venus: No Greenhouse Effect

Glass blocks IR so the camera won’t see the plant at all inside the greenhouse but rather it will only image the glass walls and ceiling like a glowing red building with opaque walls. That half of the though experiment is meaningless.
The two planets are more interesting. They will appear to be identical to an IR camera that integrates all thermal radiation. However if you look at the IR spectrum you’ll see a difference in energy distribution by frequency. The planet with more CO2 will have a deficit of radiation at CO2 characteristic absorption wavelengths and that missing energy in those bands will show up as increased energy in all the other bands.
The glass of the greenhouse and the CO2 in the atmosphere are equivalent to lens filters. The camera only sees what the filter allows it to see.

“jeff the thing that astounds me is this. people have a choice.
1. accept the basics and focus on all the uncertainty WITHIN climate science.
2. deny the basics and get pwnd in any technical discussion of the basics.”
Can you please, once and for all, tell us all just why you have the “truth” here? Is it your background? Is it your religion? What, Oracle?

Actually, Oracle Mosher should probably respond to Huffman, since he has apparently assumed the position of the final arbitrer for the physics of AGW. God help us!

By definition anything that is warmer will transmit more EM energy. A greenhouse causes the inside to be warmer so it will transmit more EM energy.
A planet that is 1C warmer (regardless of the cause) will transmit more energy. If the planet loses more energy than it receives, the excess energy loss will result in cooling until the equilibrium is reached.
Therefore the warmer planet will show as warmer until such a time that it is not warmer. Since the Earth does not instantly reach equilibrium it can lose more energy than it receives for a while, then it will cool down and likely then receive more energy than it gains until it warms up.
Any system with a lag will have such overshoot unless the PID’s are finely tuned.
John Kehr
The Inconvenient Skeptic

For a tongue in cheek explanation in plain English, both the physics and the economics are explained (in complete agreement with Jeff) here. I am not responsible for coffee, beer, or anything else that gets sprayed on keyboards at the punch line:
http://knowledgedrift.wordpress.com/climate-humour-page-the-climatologist-and-follow-the-money-series/the-physicist-and-the-climatologist-follow-the-money/
On a more serious note, not only is Jeff’s explanation accurate, consider the transition phase from doubling CO2 instantly to a new equilibrium. The physics would suggest the camera would see a ripple, or shimmer, followed by a new steady state identical to before doubling. Jeff and the physics are backed up by the data. See the paper by Beenstock and Reingewertz that looks at the climate data and concludes, yup, that’s what happens:
http://wattsupwiththat.com/2010/02/14/new-paper-on/

Jeff Id says:
January 2, 2011 at 5:18 pm
Will,
“I was not aware that gases formed and presented two dimensional heat emitting surfaces around objects such as planets.”
You should read up on basic greenhouse theory. The atmosphere has a non zero mean emission altitude, again not controversial physics. Due to the random emission direction, the intensity is uniform as though it were a disk facing you. Look up Lambertian emitter for that. You can however think of it as a shell of slightly larger diameter than the planet.
I well aware of what the basic greenhouse theory states Jeff, thank you. That is why I am here pointing out the fallacies in that theory. Points that many of which you have had to completely ignore in order to continue on with your false assertions.
You say: “The atmosphere has a non zero mean emission altitude, again not controversial physics.”
Meaning that the altitude at which the atmosphere emits radiation is not zero. Well a child could make that point so I guess you are right, well done to you. And yes that surely is not controversial physics is it, right again Jeff!
Actually the atmosphere begins to emit IR to space to any appreciable degree, in the troposphere at cloud level, around 500 meters. Which is why clouds generally begin to form at that hight. That is not controversial physics either. The atmosphere continues to emit IR all the way up to the point at which it no longer exists at all, at between 600 and 1000 kilometres.
So you see the Earths atmosphere is not a Stefan/Boltzmann two dimensional black body Lambertian radiating disk. Not even close.
That is why some of us are saying the “Greenhouse Effect” is not basic physics, it is bogus physics.
So the effective emission altitude is merely an incorrect calculation which falsely depicts the atmosphere as a two dimensional black body disk. But the Earth is neither a Lamertian scatterer nor is it a Lambertian emitter. A Lambertian surface is by definition a two dimensional black body disc. Spheres are not Lambertian surfaces. Particularly spheres that are strongly light from one side by bright stars. And particularly Spheres which posses thick gaseous atmospheres which above a few hundred meters, emit radiation in three dimensions (four if you include time).
You appear to be confusing/mixing emission with albido with regards to Lambertian surfaces. The Atmosphere most certainly does not have a uniform emission intensity. That is why it has a 600 km high bulge on one side the equivalent of 25% of the Earths surface area which tracks the solar point around the Earth and disappears below the Mesosphere at 100 km on the dark side. You know Jeff, its called night and day. Its not controversial physics.
See here: http://www.spinonthat.com/CO2_files/The_Diurnal_Bulge_and_the_Fallacies_of_the_Greenhouse_Effect.html
and here:
http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1966SAOSR.207…..J&db_key=AST&page_ind=0&plate_select=NO&data_type=GIF&type=SCREEN_GIF&classic=YES
This is why the Earth is not a Stefan/Boltzmann two dimensional black body radiator nor a Lamertian emitting (or scattering) surface.
The so called “Greenhouse Effect” is based on arbitrary calculations, ambiguous assumptions and false science. Is it really any wonder that it can only exist in half baked thought experiments and cannot be physically demonstrated in reality?
Physics that cannot be demonstrated in reality by experiment, is nothing more than statistics.
Statistically speaking, “the tail wags the dog” is a valid statement.

Doubling CO2 does not double the greenhbouse effect. Heinz Hug shows that it
only increases 0.17 %.

Will is correct, IMHO. Heat Storage is the key. Rocks radiate back and forth, too, but we don’t call that a “greenhouse effect.”
It’s interesting watching people DEMAND that they are correct on issues that are as clear as mud!

Jeff Id says:
January 3, 2011 at 7:20 am
Will,
I cannot follow any of what you have written other than you are not happy. Typically, I can follow a science discussion fairly well so hmm…. I’ve also taken a few minutes to check your internet work linked above and can’t follow that either. Weird statements about photons all followed by declarations of certainty that AGW is impossible.
If you have a question, I’m happy to try and answer but this discussion isn’t going anywhere.
Jeff,
I have given a clear example of a thought experiment which can be readily reproduced. and proves that the so called “Greenhouse Effect” is a false perpetual motion machine that does not occur in the real world.
Once again here: http://wattsupwiththat.com/2011/01/01/greenhouse-thought-experiment/#comment-564125
Simply, adding more bricks to a night storage heater does not increase the temperature, in fact the overall effect is a reduction in temperature because the energy is more widely transmitted and the “negative feedbacks” dominate. Still you don’t have to take me at my word you can do the experiment in the real world and see for yourself.
My Diurnal Bulge paper has been reviewed by thousands of individuals with scientific backgrounds and some have even stated that it makes more sense to them than anything they have ever read on the subject. It got two wow’s from a member of Mensa, though not being a name dropper I won’t mention it here.
One very well known IPCC reviewer (again no names) called it “another attack on the Steffan/Boltzmann law”, but I corrected him as per my above posts on that subject and he quickly fell silent on the issue.
And finally I have reproducible real world experimental evidence which back up the fact that increasing CO2 does not cause an increases in temperature.
It is no surprise to me that you feel this discussion is going nowhere Jeff!
As far as any questions I may want to ask you Jeff, I can’t think of anything in particular but thanks all the same.

I’ve bucked many a hay bale on the Great Plains (Eastern CO, to be exact), and I’m very familiar with the weather patterns out there. The cool dry artic air plays tag with the humid air from the Gulf all year long, sometimes creating violent storms. But often the humid air just gradually replaces the dry air without even causing clouds. So some clear July days have high humidity and some have low humidity, even when the soil is as dry as toast. But despite the wide variations in humidity on these clear days, temperatures are NOT hotter on the humid days. Water vapor is the strongest greenhouse gas. If the greenhouse effect were all that important, it seems to me that one should see hotter weather on humid days.

wayne says: Mike D. … [your] crude remarks to marginalize many here are not needed from your shallow and incorrect viewpoint.
Whoops. My bad. Sorry, your worship. Far be it for me to disturb majestic thinking.
The “thought experiment” proposed to measure (or sense) the warmth (escaping thermal radiation) of two plants, one in a greenhouse and one “in open air”. The assumption is that both plants are “thermally stable (temperature isn’t changing)”.
Pardon my ignorance, doctor, but if an object is thermically stable, doesn’t that mean it radiates no energy at all? Other than fissioning (matter become energy) atoms, what undisturbed matter radiates energy but doesn’t change temperature?
Of course, I am not a physicist, so I have no clue. I do know that greenhouses trap heat, but that’s just my empirical finding, based on my lying eyes, and not on theoretical physics about which I know less than nothing. My tiny brain can’t grasp the problem.
I see that Mr. Id has now given his answer, “In … thermally stabilized systems … energy into the system is equal to energy out.” Pretty much what I said above. He goes on, “Therefore the camera will show the greenhouse plant as warmer (brighter) than the free air plant.”
Stunning. The plant in the greenhouse will be warmer. Who’d a thunk it? Besides me, I mean, and 29.8% of the poll takers. The other 70.2% think the plant in the greenhouse would be the same temperature or cooler. And I’m the shallow and incorrect one?
Mea culpa. I bow down to the giants of theoretical physics. I’m just a hick from the sticks who happens to own and operate a greenhouse. I think it’s warmer in there, but what do I know?

Tim
You have simply exchanged a transmitting substance for a non-transmitting/insulating substance. And then try to imply that it is the same experiment.
Am I not supposed to notice that “clever” slight of hand?
Or are you one of those people who believe CO2 is a heat “trapping gas”?
“High IQ does not in any way correlate to an understanding of GHGs.”
Interestingly enough, believe it or not, neither does a low IQ.
FYO the Mensa guy was a chemical analyst but my only point was simply that Jeff was not very convincing when he claimed that he didn’t understand my posts or that they are quote: “unintelligible”
There are many who would disagree.

Jeff Id says:
January 2, 2011 at 5:18 pm
ourson polaire,
The image would be larger and slightly dimmer so no physics are violated.

Of course no physics are violated. I just don’t understand exactly how and why. I’m aware of the fact that you don’t want to get too much into detail, but if we don’t think it through to the end it’s not a thought experiment but rather an illustration of a preconceived concept. And we have too much of this already. Maybe someone else can help?
Following the arguments brought up by Michael Hammer above, Jeff’s (and my) statement that the image of the 2x CO2 planet is “larger and dimmer” (however slightly) is not correct. The outmost layers of the atmosphere, the stratosphere and above, are not affected by a doubling of CO2, therefore the size of the image of our “warmer” planet would not be different from the “cooler” planet. (The proposed higher emission altitude due to doubling of CO2 would just affect the brightness in that part of the image, not the overall size.)
I would restate: The images of both planets have the same size and overall brightness, but the distribution of thermal radiation might be slightly different.
The surface of the 2xCO2 planet will be a little brighter (because Jeff said so, basic physics) therefore some part of the atmosphere must appear cooler.
But how exactly does the troposphere or the tropopause get cooler when the surface warms up? That’s what I still don’t understand.
I understand the tropopause is emitting energy in the CO2 absorption bandwidth because there is not much CO2 in the tropopause to block it. The tropopause of our 2xCO2 planet gets the same energy form above (the sun and the stratosphere) and a little less energy from below in the CO2 absorption bandwidth. But isn’t this counteracted by more radiation at all other frequencies? Therefore I would say the tropopause on either planet is emitting the same amount of energy but maybe at slightly different frequencies. (Our camera won’t notice.)
In the troposphere we have most of the CO2 effect. As far as I understand it, it is like this: CO2, like any other gas, is absorbing all kinds of frequencies from above and below and is emitting the same amount of energy at slightly different frequencies because it is not emitting in its absorption bandwidth. We said before: if the surface is warmer now, some part of the atmosphere must be cooler. And CO2 is responsible. Is CO2 cooling the troposphere?
Most likely some of my reasoning is totally wrong, because if not, CO2 would help to transform the “dangerous” long wave radiation form the surface to less dangerous frequencies and may be even cooling parts of the atmosphere. What am I missing?
I am sure all the politicians understand how the climate works by now. Could somebody please help an economist understand it – in the end, it will land on our desks.
Thank you all.

Having said all that Dr. Roy Spencer is still a hero of mine and he has a good article on his blog today. You should all read it!

Dude, you are boring.

Tim
Mum said I mustn’t feed the Troll’s!

Only reading the first couple responses (so I couldn’t cheat), I’d say the 2 planets will have the same integrated “brightness”, but the one w/more CO2 will have its spectrum shifted to slightly lower frequencies (a cooler TOA). If your camera just measured bulk (integrated) radiation w/o considering frequency, it would show no difference in watts emitted.

Yes, Jeff ID it would help if you could tell me where that “new Bottleneck” is. According to the IPCC’s own models a bottleneck (i.e. warming by greenhouse gases) would create a “Hot Spot” just below that bottleneck. IPCC models even pin pointed where that Hotspot should or could be found.
No “Hot Spot” has ever been found. And quite meekly we seem to agree with the AGW crowd “That it does not matter anyway.” Maybe that is because a missing hot spot proves there is no Natural Greenhouse effect either.
Power v. energy: All Energy Flow Plans use the same description for energy in as for energy out, i.e. W/m². They even say “energy out equals energy in”

Jeff Id says:
January 4, 2011 at 7:22 am
“Will:
January 3, 2011 at 8:26 pm
I can’t understand you again. You have heat capacity mixed with absorption mixed with mashed potatoes again.”
CO2, O2 and N2
Thermal Conductivity – k – (W/mK)
Temperature (ºC)
Carbon dioxide (gas) 0.0146
Nitrogen 0.024
Oxygen 0.024
Specific Heat Capacity
cp cv
(kJ/kg K) (kJ/kg K)
Carbon dioxide CO2 0.844 0.655
Nitrogen N2 1.04 0.743
Oxygen O2 0.919 0.659
“The specific heat capacity represents the amount of energy required to raise 1 kg by 1oC, and can be thought of as the ability of a substance to absorb heat. Therefore the SI units of specific heat capacity are kJ/kg K (kJ/kg oC). Water has a very large specific heat capacity (4.19 kJ/kg ºC) compared with many fluids.”
Water is a good heat carrier!
From: http://www.engineeringtoolbox.com/heat-work-energy-d_292.html
So as you might expect, water has a much higher specific heat capacity than CO2. Well guess what? So does O2 and N2 as you can see above.
But wait, didn’t Jeff Id tell us in his amazing, impossible to reproduce, “thought experiment” that quote:
“We know that CO2 absorbs certain outgoing wavelengths of light.”
So surely that must mean that CO2’s ability to absorb a tiny portion of IR in the 15 mµ region of the IR spectrum means it is a really scary “Greenhouse Gas” and is so powerful that it determines the temperature of the entire atmosphere right?
Because we all know that absorption of tiny portions of the IR spectrum trumps the specific heat capacities of gases and their ability to absorb heat don’t we. You know “heat”, that stuff that melts ice and causes “global warming”.
Well lets try another thought experiment shall we:

Oopsie!
That was a REAL easily reproducible experiment, not an impossible to replicate and therefore impossible to validate post normal “thought experiment”.
Sorry, my bad!
When a CO2 molecule absorbs energy in the form of light/IR, the energy will cause the CO2 molecule to vibrate faster (become hotter). But if that CO2 molecule is at the same time being forced into temperature equilibrium by the higher specific heat capacities of both O2 and N2 in which it is immersed at a ratio of more than 1200/1, the only thing the CO2 molecule can do is re-emit (becoming cooler).
Therefore the dominant factor in the atmosphere with regard to energy and more importantly, temperature, is specific heat capacity not radiation. I back this up with real easily replicable experiments. NOT impossible to replicate post normal “thought experiments”.

Jeff, I would still like to know the scientific explanation/answer to my oft repeated question: How are gases like Nitrogen, Oxygen and Argon warmed if they cannot absorb IR radiation?

Thank you Jeff for what you posted on January 4, 2011 at 4:53 pm It is going to take me longer than a few hours to soak it all up. But it is in the middle of the night here where I am just now (02:00) so I shall have to answer it at some other time. As I have got to “hit the sack” now.

““Jeff, I would still like to know the scientific explanation/answer to my oft repeated question: How are gases like Nitrogen, Oxygen and Argon warmed if they cannot absorb IR radiation?”
Well, who said they couldn’t? I see IR in the oxygen band! See fig 2. It sounds like you’ve been reading Will’s blog.”
WOW, now I’m gobsmacked again! Jeff, don’t you know ANYTHING about thermalization? ALL the atmosphere has to be warmed to preserve LTE, and for the non-IR active diatomic molecules, this happens via THERMALIZATION. Google it!

The full quote should be:
“When a CO2 molecule absorbs energy in the form of light/IR, the energy will cause the CO2 molecule to vibrate faster (become hotter). But if that CO2 molecule is at the same time being forced into temperature equilibrium by the higher specific heat capacities of both O2 and N2 in which it is immersed at a ratio of more than 1200/1, the only thing the CO2 molecule can do is re-emit (becoming cooler).
Therefore the dominant factor in the atmosphere with regard to energy and more importantly, temperature, is specific heat capacity not radiation. I back this up with real easily replicable experiments. NOT impossible to replicate post normal “thought experiments”.
Another quote from my first post is also worth repeating here.
“The so called “Greenhouse Effect” is nothing more than a cheep parlour trick which utilises the complexities of atmospherics and fluid dynamics and most peoples inability to simultaneously consider all of the variables.”
That means all of us.
How many times have I read people saying in this thread (including Jeff Condon), well you have to accept the basic physics, if you can’t do that then blah blah blah?
Basic physics my arse!
Lets have a brief look at the basic physics of the “Greenhouse Effect” hypothesis.
Or rather lets look at just a fraction of the “basic physics” which the “Greenhouse Effect” hypothesis fails to incorporate.
Such as:
The ideal gas law
Specific heat capacity
All three laws of thermodynamics
Conduction
Convection
Solar variability
Solar magnetism
Solar ionisation
Temporary di-pole moments
The Diurnal Atmospheric Bulge, etc, etc.
Thats not to mention the lack of correlation between temperature and enormous levels of CO2 up to 7000 ppm in the historical record. Or the multitude of other climatic variables which are proven to effect global temperature yet have nothing whatsoever to do with any kind of “Greenhouse Effect”.
I know I certainly don’t have all the answers, not by any stretch of the imagination. It is perfectly obvious to anyone that I am not a scientist. But one thing I know for sure is that if we do not consider every parameter involved, we can never fully understand the “basic physics” let alone the climate.
Those who support and promote the “Greenhouse Effect” hypothesis could not possibly be further from understanding “basic physics”.
The “Greenhouse Effect” hypothesis is NOT basic physics. It’s half baked physics. It’s incomplete physics. It’s dumbed down physics. It’s retarded physics. Above all the “Greenhouse Effect” hypothesis is bullsh!t physics.
Of all those who think they understand the basic physics of the “Greenhouse Effect”, how many of you have actually read John Tyndall’s ” Contributions to Molecular Physics in the Domain of Radiant Heat”?
Not one I bet.
You will therefore be blissfully unaware that this work, from which the “basic physics” of the “Greenhouse Effect” hypothesis originates, contains the classic structure of the “basic” confidence trick. Using as it does, the “Straw Man” device in the form of Professor Magnus, to convince the reader that Tyndall is correct in all of his fallacious assertions such that, Oxygen and Nitrogen are quote: “practically transparent radiant heat”. and his implication that CO2 is a heat trapping gas, among many other fallacies.
Don’t talk to me about the basic physics.
If increasing CO2 content causes increasing air temperature show it, with REAL replicable experiments. How hard can it be? After all, its just basic physics right?
To imply or actually state as many fools have, that you would need another planet, identical to our world but with double the CO2 concentrations in order to demonstrate the “Greenhouse Effect”, perfectly characterises the level of dishonesty and moral bankruptcy of its proponents.

Will says:
January 5, 2011 at 4:25 am
“To imply or actually state as many fools have, that you would need another planet, identical to our world but with double the CO2 concentrations in order to demonstrate the “Greenhouse Effect”, perfectly characterises the level of dishonesty and moral bankruptcy of its proponents.”
Good grief, of course you don’t! Much simpler experiments that anyone can carry out are described on the internet – Google “greenhouse effect demonstration”.
The simple “vinegar and baking soda in a jar” experiment is described here: http://www.rmets.org/activities/schools/greenhouse-effect.php
There’s a nice video of a more sophisticated setup here: http://www.youtube.com/watch?v=Ge0jhYDcazY

Jeff Id says January 4, 2011 at 4:53 pm :
O H Dahlsveen says January 4, 2011 at 3:38 pm: “Jeff, I would still like to know the scientific explanation/answer to my oft repeated question: How are gases like Nitrogen, Oxygen and Argon warmed if they cannot absorb IR radiation?”
Jeff: “Well, who said they couldn’t? I see IR in the oxygen band! See fig 2. It sounds like you’ve been reading Will’s blog.” (Jeff sends me a link which I promised to look at later, as a quick look took up all the time I could spare right then.)
OHD: Well, I have for a long time been of the opinion that they can, as the few air-molecules present as high up as the Thermosphere are said to be N² and O² I have of course got no idea whether they are exited/warmed by short-wave IR, gamma or by x-ray radiation. But The IPCC and other “Greenhouse specialists” have given me the impression that they cannot be warmed by either incoming short wave IR or by out-going long wave IR.
So if 99% of the atmosphere (Nitrogen78%+Oxygen21%+Argon0.9%) cannot be warmed by radiation and at the same time heat exchange between the top of the surface and the bottom of the atmosphere by conduction is so unthinkable these days that it is never even mentioned, I feel I have got to ask: How is atmospheric heating accomplished? As to ignore conduction between the two is to ignore The Zeroth Law of Thermodynamics. (Unless there is a vacuum between the surface and the atmosphere that I don’t know about).
And yes, I have been reading Will’s comments but I did not know he had his own blog. So – no, I haven’t.
Jeff: “One of the things I’ve done at tAV is to try and make things as simple as possible so I’ve made a few posts like this. BTW, Figure 2 of that post should convince every person on the planet that CO2 warming is real. What it shouldn’t do is convince people that it warming is big, dangerous, bad, slightly measurable, significant, or in any way not good. Those points are separate issues.”
OHD: “We may be talking or writing at “cross purposes” here. – If you are not trying to convince me, and others, that warming (by CO²) is big, dangerous, bad, slightly measurable (or measurable at all), significant, or in any way not good. Then we are more or less in agreement as I have no problem with understanding that certain gases, especially Water vapour, has better heat retention capacities than others. And I do understand that the planet is “warmer over all” i.e. warmer on the night side and cooler on the day side than it otherwise would be. However only an atmosphere that can stop or delay both convection/evaporation and if you please radiation can hope to have a “greenhouse effect”
Jeff: Well, as an optical engineer I’ve worked this math often, and were you to even slightly consider chucking this simple stuff out (as you suggest), you should chuck every incandescent light out of your window. I mean right out the window b/c it turns out that if the math is bad, incandescent lights must not function.
OHD: The Governments are chucking the incandescent light bulbs out for us in any case Jeff. It is not the maths that is wrong. The maths get the same answer irrespective of what the atmosphere is made up of. Irrespective of whether the planet is the size of a pea or the sun, Whether it is completely dry or 100% water.
But as you mention the incandescent light bulb, the filament is maybe as close to a “blackbody” as a star is but what do you think cools the bulbous glass bit of the bulb? Why is the air above the bulb warmer than the air just below it when the bulb is lit?
When I was at primary & middle schools (1947 – 1954) we were told by our teacher that a “doubleglazed” light bulb had once been made, i.e. glass vacuum – glass vacuum – filament. When the bulb was lit, the inner glass soon melted. (This was done as an experiment to prove that in the atmosphere, conduction/convection was stronger than radiation.) – I have never found any references to this experiment, but then again I never thought I had to as by the time I was a mechanical engineer (1964) those principles had not changed. The interest in global warming (that had just stopped) was as high in those days as now, the difference was that then they were still looking for an explanation for “The Ice Ages” (At the time The Milankovitch Theory” was out of the window as summer in the Northern Hemisphere was thought to take place just as the earth was at its furthest point from the sun in its eliptical track. As long as the orbit stayed the same size the shape of it should not matter enough for a big freeze. (But that’s another story)
So to be fair, as a mechanical engineer I have never come across a thermo-dynamical problem that has been in need of Planck’s Law. Even when I briefly worked for the “Nuclear Power Industry” the only “extra thing” I had to learn about radiation was how to shield it, avoid it and de-contaminate myself. But then again, I was not designing the reactors.
Jeff: Watts are power not energy, the measure is Joules per second – energy flow. Joules are energy, Joules per second are power. So when you say energy in Watts/meter^2, the term “energy” is incorrect. The Watt unit is actually power.
OHD: I know, but tell that to the IPCC and Trenberth & al

Jeff Id says on January 5, 2011 at 3:56 pm:
“OHD, My best guess is that CO2 has an immeasurably small effect on our climate, that doesn’t change the basics of this post.”
After reading the above and your further answers to my comments I have come to the conclusion that there are perhaps ‘not such a big difference’ between the ways we look at these things.

“The specific heat capacity represents the amount of energy required to raise 1 kg by 1ºC, and can be thought of as the ability of a substance to absorb heat. Therefore the SI units of specific heat capacity are kJ/kg K (kJ/kg ºC). Water has a very large specific heat capacity (4.19 kJ/kg ºC) compared with many fluids.”
From: http://www.engineeringtoolbox.com/heat-work-energy-d_292.html
Please see this link. Specific heat capacity is key to understanding atmospheric temperature, as is obvious from the information there.
Jeff says:
“Heat capacity is another matter entirely. It only determines how quickly the gas changes temperature. If the heat capacity of Air were 10x greater than we think it is, it would only affect the reaction time of warming — slightly.”
Well sorry but I don’t buy that, mostly because of what I have read on the subject and also based on that knowledge because it sounds to me like Jeff just made that up. Besides, reaction time of warming is not the point.
Specific heat capacity is the determining factor of the temperature at thermal equilibrium of all gas mixtures. So not only do the most abundant gases dominate but if they also have a higher specific heat capacity then there’s simply no arguing.
The point is can 385 parts per million CO2 determine the temperature of 999,615 parts per million O2 and N2 or is it more likely that 999,615 O2 and N2 molecules in every million will force the 385 CO2 to cool. Particularly considering that O2 and N2 both have higher specific heat capacities than CO2.
See here: http://www.engineeringtoolbox.com/spesific-heat-capacity-gases-d_159.html
I know Jeff is very convincing and all but it has to be said that it stretches credulity somewhat. But the clincher for me has to be the fact that there is zero evidence for Jeff’s claims. Jeff provides no evidence whatsoever and simply expects us all to take his word for it because he knows best.
Our everyday evidential experience tells us that a few hundred warm molecules will be cooled by almost a million cooler molecules, not the other way round.
Sorry if I seem pedantic but I need proof. I don’t have any religious tendencies.
To claim that the effect is so tiny that it probably can’t effect anything, about something that you can provide no evidence for in the first place, is pretty much the same as saying it doesn’t exist at all when all is said and done.
I mean if it’s that tiny of an effect would it not be just as valid to say that the O2 and N2 is cooling the CO2, rather than the CO2 is actually warming the O2 and N2. If it’s that close to call isn’t that what is referred to as semantics?
That is what it seems to have come down to with Jeff’s position here.
But with a concession to all those who have staked their reputation on the fraud, it kind of gets them off the hook, but it gives little comfort to those of us who’s governments seem intent on pushing ahead with Carbon taxes regardless, like here in the UK.
REPLY: take it over here please, you’ve been called out:
http://noconsensus.wordpress.com/2011/01/05/kicking-puppies/
This thread is closed to this argument. – Anthony

JeffID: You seem to be ignoring the important parts of my comments to you. Why? I am still waiting for your response to the link I provided above. WHY is the temperature on all the planets so close to ours when assessed at a pressure of 1 bar? Can you explain this with the “greenhouse theory?” Of course not! Somehow,most people cannot think beyond the “box of radiation cartoons!” It is truly wierd!