Visualizing the "Greenhouse Effect" – Atmospheric Windows

Guest post by Ira Glickstein

A real greenhouse has windows. So does the Atmospheric “greenhouse effect”. They are similar in that they allow Sunlight in and restrict the outward flow of thermal energy. However, they differ in the mechanism. A real greenhouse primarily restricts heat escape by preventing convection while the “greenhouse effect” heats the Earth because “greenhouse gases” (GHG) absorb outgoing radiative energy and re-emit some of it back towards Earth.

The base graphic is from Wikipedia, with my annotations. There are two main “windows” in the Atmospheric “greenhouse effect”. The first, the Visible Light Window, on the left side of the graphic, allows visible and near-visible light from the Sun to pass through with small losses, and the second, the Longwave Window, on the right, allows the central portion of the longwave radiation band from the Earth to pass through with small losses, while absorbing and re-emitting the left and right portions.

The Visible Light Window

To understand how these Atmospheric windows work, we need to review some basics of so-called “blackbody” radiation. As indicated by the red curve in the graphic, the surface of the Sun is, in effect, at a temperature of 5525ºK (about 9500ºF), and therefore emits radiation with a wavelenth centered around 1/2μ (half a micron which is half a millionth of a meter). Solar light ranges from about 0.1μ to 3μ, covering the ultraviolet (UV), the visible, and the near-infrared (near-IR) bands. Most Sunlight is in the visible band from 0.38μ (which we see as violet) to 0.76μ (which we see as red), which is why our eyes evolved to be sensitive in that range. Sunlight is called “shortwave” radiation because it ranges from fractional microns to a few microns.

As the graphic indicates with the solid red area, about 70 to 75% of the downgoing Solar radiation gets through the Atmosphere, because much of the UV, and some of the visible and near-IR are blocked. (The graphic does not account for the portion of Sunlight that gets through the Atmosphere, and is then reflected back to Space by clouds and other high-albedo surfaces such as ice and white roofs. I will discuss and account for that later in this posting.)

My annotations represent the light that passes through the Visible Light Window as an orange ball with the designation 1/2μ, but please interpret that to include all the visible and near-visible light in the shortwave band.

The Longwave Window

As indicated by the pink, blue, and black curves in the graphic, the Earth is, in effect, at a temperature that ranges between a high of about 310ºK (about 98ºF) and a low of about 210ºK (about -82ºF). The reason for the range is that the temperature varies by season, by day or night, and by latitude. The portion of the Earth at about 310ºK radiates energy towards the Atmosphere at slightly shorter wavelengths than that at about 210ºK, but nearly all Earth-emitted radiation is between 5μ to 30μ, and is centered at about 10μ.

As the graphic indicates with the solid blue area, only 15% to 30% of the upgoing thermal radiation is transmitted through the Atmosphere, because nearly all the radiation in the left portion of the longwave band (from about 5μ to 8μ) and the right portion (from about 13μ to 30μ) is totally absorbed and scattered by GHG, primarily H2O (water vapor) and CO2 (carbon dioxide). Only the radiation near the center (from about 8μ to 13μ) gets a nearly free pass through the Atmosphere.

My annotations represent the thermal radiation from the Earth as a pink pentagon with the designation for the left-hand portion, a blue diamond 10μ for the center portion, and a dark blue hexagon 15μ for the right-hand portion, but please interpret these symbols to include all the radiation in their respective portions of the longwave band.

Sunlight Energy In = Thermal Energy Out

The graphic is an animated depiction of the Atmospheric “greenhouse effect” process.

On the left side:

(1) Sunlight streams through the Atmosphere towards the surface of the Earth.

(2) A portion of the Sunlight is reflected by clouds and other high-albedo surfaces and heads back through the Atmosphere towards Space. The remainder is absorbed by the Surface of the Earth, warming it.

(3) The reflected portion is lost to Space.

On the right side:

(1) The warmed Earth emits longwave radiation towards the Atmosphere. According to the first graphic, above, this consists of thermal energy in all bands ~7μ, ~10μ, and ~15μ.

(2) The ~10μ portion passes through the Atmosphere with litttle loss. The ~7μ portion gets absorbed, primarily by H2O, and the 15μ portion gets absorbed, primarily by CO2 and H2O. The absorbed radiation heats the H2O and CO2 molecules and, at their higher energy states, they collide with the other molecules that make up the air, mostly nitrogen (N2), oxygen (O2), ozone (O3), and argon (A) and heat them by something like conduction. The molecules in the heated air emit radiation in random directions at all bands (~7μ, ~10μ, and ~15μ). The ~10μ photons pass, nearly unimpeded, in whatever direction they happen to be emitted, some going towards Space and some towards Earth. The ~7μ and ~15μ photons go off in all directions until they run into an H2O or CO2 molecule, and repeat the absorption and re-emittance process, or until they emerge from the Atmosphere or hit the surface of the Earth.

(3) The ~10μ photons that got a free-pass from the Earth through the Atmosphere emerge and their energy is lost to Space. The ~10μ photons generated by the heating of the air emerge from the top of the Atmosphere and their energy is lost to Space, or they impact the surface of the Earth and are re-absorbed. The ~7μ and ~15μ generated by the heating of the air also emerge from the top or bottom of the Atmosphere, but there are fewer of them because they keep getting absorbed and re-emitted, each time with some transfered to the central ~10μ portion of the longwave band.

The symbols 1/2μ, , 10μ, and 15μ represent quanties of photon energy, averaged over the day and night and the seasons. Of course, Sunlight is available for only half the day and less of it falls on each square meter of surface near the poles than near the equator. Thermal radiation emitted by the Earth also varies by day and night, season, local cloud cover that blocks Sunlight, local albedo, and other factors. The graphic is designed to provide some insight into the Atmospheric “greenhouse effect”.

Conclusions

Even though estimates of climate sensitivity to doubling of CO2 are most likely way over-estimated by the official climate Team, it is a scientific truth that GHGs, mainly H2O but also CO2 and others, play an important role in warming the Earth via the Atmospheric “greenhouse effect”.

This and my previous posting in this series address ONLY the radiative exchange of energy. Other aspects that control the temperature range at the surface of the Earth are at least as important and they include convection (winds, storms, etc.) and precipitation that transfer a great deal of energy from the surface to the higher levels of the Atmosphere.

I plan to do a subsequent posting that looks into the violet and blue boxes in the above graphic and provides insight into the process the photons and molecules go through.

I am sure WUWT readers will find issues with my Atmospheric Windows description and graphics. I encourage each of you to make comments, all of which I will read, and some to which I will respond, most likely learning a great deal from you in the process. However, please consider that the main point of this posting, like the previous one in this series, is to give insight to those WUWT readers, who, like Einstein (and me :^) need a graphic visual before they understand and really accept any mathematical abstraction.

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etudiant
February 28, 2011 2:18 pm

Relative humidity in the upper atmosphere (300mb level) has fallen from around 55% in 1950 to about 45% now.
Should this not have a material impact on the greenhouse effect?
It is hard to get concerned when such substantial changes don’t even warrant discussion, much less explanation. Or is there some obvious offset that makes this moot?

Gerry
February 28, 2011 2:27 pm

I realize the first graphic is attributed to Wikipedia, but I am used to wavelength graphs with the longer wavelengths (lower frequency) on the left and shorter wavelengths (higher frequency) on the right. Also confusing are the colors which are backwards from the norm.
Unless 2/3 of a beer has completely ruined me mentally (I’m willing to negotiate that point)…
Of course, the warmists have manipulated every other convention of science and engineering, so what’s new?
Gerry

Fred Souder
February 28, 2011 2:31 pm

Ira,
Are there any experiments which detect the incoming re-emitted radiation from the atmosphere? Did a quick search and only came up with models. It seems like we should be able to detect the radiation coming back at us from the atmosphere if this model is valid.

RJ
February 28, 2011 2:34 pm

Does it heat the earth or does it slow the rate of cooling?
I do not think you should say its a scientific truth etc. It’s a theory that some experts do not agree with.
I’m not an expert but I have a problem with a cold body (a small amount of CO2 and water vapour) heating a much larger warmer earth. Logically it does not seem right. If for example a human was put into a container filed with CO2 would they cook or warm up. I do not think so.
And does energy leave the earth mainly by convection or radiation.
Slaying the sky dragon addressed these issues. Maybe our understanding of this issue is still not that advanced and the majority viewpoint is flawed.

Russell Duke
February 28, 2011 2:35 pm

Can you please give me the references for CO2 IR re-emittance

mpaul
February 28, 2011 2:40 pm

Ira, I think this explanation is clearly written and understandable and is helpful to people who are new to the topic or who are less technically inclined.
Most serious skeptics have little disagreement with the basic physics of the green house effect. The big issue (as you point out) is sensitivity. Many of us believe that sensitivity is a function of a large number of interrelated variables and as such lends itself to stochastic modeling rather than deterministic modeling. I’d be interested in your comments on this regard.
Many on the True Believer side argue that the skeptics don’t ‘understand simple physics’ when the discussion turns to the green house effect. In fact, what the skeptics argue is that the green house effect is anything but simple and that the simplistic modeling approaches so in vogue with the AGW crowd are naive. Having said that, I do like Pielke’s approach of measuring ocean heat content anomaly as the best way to estimate sensitivity.

Gil Dewart
February 28, 2011 2:45 pm

Finally someone has addressed the “atmospheric window” effect. There is a lot more to be said, but for now, “it’s about time”.

February 28, 2011 2:48 pm

Most of the above is well understood by many (but not all) on both sides of the argument. The AGWs think that the solar input is constant, but the output is affected by CO2 (hence hockey stick).
Sceptics think that the solar input is variable so the output has to change accordingly.
There is also possibility of a half way house:
Solar input is constant, but the energy storage – release relationship is not a linear function, but kind of thermal hysteresis, where the oceans absorb and store large chunks of energy well above the equilibrium, followed by more than the accumulated excess release. The effect of this is a sequence of the warm periods (roman, medieval & current one) separated by the cooler ones.

February 28, 2011 2:52 pm

From the looks of that first chart, ~100% of 7μ and 15μ radiation gets absorbed by the atmosphere on the way back to space, mainly by H20 and CO2. Maybe a tiny trickle bounces its way from molecule to molecule and makes it to space.
If that’s so, then doubling or even tripling the values of H2O in our atmosphere should have no effect on absorbtion. You can’t absorb more than 100% of the radiation, right?

Bryan
February 28, 2011 2:52 pm

Your graphs are completely misleading.
They show that the intensity of the Solar Radiation as being equal to the Earth surface IR upward radiation.
Did you really intend to show this?
Further the colder atmosphere cannot heat or “warm” the warmer Earth Surface.
All it can do is to slow to some extent the heat loss from the surface.

Fred Souder
February 28, 2011 2:52 pm

RJ,
I would guess that the vast majority of energy leaves earth by radiation. It has recently been discovered that our atmosphere is being continuously shed by the solar wind, and replenished by volcanism. This would be the only vehicle for convection that I can think of, and no idea if it is significant.

Fred Souder
February 28, 2011 2:54 pm

Gerry,
I must be that 2/3 beer. You should have downed the whole draft. Most physics and chemisry texts go from shorter to longer, left to right.

Scottish Sceptic
February 28, 2011 2:56 pm

“Other aspects that control the temperature range at the surface of the Earth are at least as important and they include convection (winds, storms, etc.) and precipitation that transfer a great deal of energy from the surface to the higher levels of the Atmosphere.”
I would suggest CO2 in the atmosphere is much like the “correct” expanation of the Crookes radiometer (the black and white rotating thing in a glass vacuum bulb).
According to one theory, the black absorbs light so it rotates away from the light, or is it that the black emits IR? Or is it that the black surface is slightly hotter therefore the few air particles exhibit a higher pressure. Or to put it correctly: “Over the years, there have been many attempts to explain how a Crookes radiometer works:” http://en.wikipedia.org/wiki/Crookes_radiometer.
Just like the Crookes radiometer, carbon dioxide doesn’t just absorb IR, it also emits it. It doesn’t just interact with heat from the surface, it also interacts with the cold of space.
The so called “science” of global warming can be completely turned on its head: increasing CO2 blocks heat being emitted by the earth –> increased CO2 emits more radiation to the cold sink of space.
Just like the Crooke radiometer, the “obvious” explanation is neither obvious when you look at the deatils nor (in the case of the “greenhouse” effect which is a convective blocking effect.) is it right.

wayne
February 28, 2011 2:58 pm

Ira, first, I think I will mostly agree with your entire post and that’s a great animated visual, but a question; where in the heck did 5525K for the sun’s temperature come from? Is that a hypothetical effective temperature as if all albedo and reflection has already been removed and falling on a flat Earth? (sounds like more Wikipedia’s hidden ‘clarity’)

Dan in California
February 28, 2011 2:59 pm

Inspection of the infrared absorption windows for CO2 and H2O shows the much greater greenhouse effect of H2O. Yet I’ve often heard that the H2O only appears in the computer models as being forced by CO2, and therefore it doesn’t matter that H2O is a far more effective greenhouse gas than CO2. (People who want to regulate CO2 generation say this) My opinion is that the sensitivity to CO2 is weak, and it is an artifact of the written models that show CO2 effects predominating over H2O. Furthermore, because H2O changes from gas to liquid and back again, the H2O may even have a negative, regulating influence on the CO2 contribution to the greenhouse effect. Certainly the density driven convection caused by cloud formation and evaporation has a strong stirring effect that carries heat aloft. (A key difference between Earth and Venus is Venus’ lack of winds and vertical convection that carry heat upward)
I would like to see a discussion of these issues, as I think this is key to the AGW enthusiast/ skeptic differences of opinion.
Thanks,
Dan

jknapp
February 28, 2011 3:01 pm

Thanks Ira. Interesting post. A couple of questions, which will undoubtedly demonstrate my lack of physics knowledge. I thought that atoms emitted photons based on quanta specific to that atom. As such the H2O and CO2 molecules will absorb and emit only specific wavelengths. That would also be true of the O2 and N2 molecules. But here you are talking about “blackbody radiation” doesn’t that imply that the wavelength emitted will not be specific to the molecule but will, instead, be a function of the temperature. Is there a conflict here or is it a misunderstanding on my part?
Assuming that my understanding will be resolved, then a further understanding on my part was that the 7u and 15u wavelengths were absorbed very quickly (in terms of distance traveled through the atmosphere. That would it seems to me to effectively “trap” the energy in a fairly narrow region with the vast amount of the energy kinda just hanging around near where it was absorbed neither going up or down very far due to radiation. That then would heat that region resulting in expansion and the physical raising of the molecules. This convective upward flow of the energy would be dominant over the downward portion of the radiative flow. Thus the energy would be lifted toward space. As it got higher more and more would escape outward and the downward radiative portion would serve mainly to keep the convection going with then very little energy actually being returned to the surface.
Thus you mentioned convection as not being treated here but isn’t it possible that convection is a dominant not secondary driver of energy transmission out.
Thanks for any enlightenment you can give me.

wayne
February 28, 2011 3:09 pm

etudiant says:
February 28, 2011 at 2:18 pm
Relative humidity in the upper atmosphere (300mb level) has fallen from around 55% in 1950 to about 45% now.
Should this not have a material impact on the greenhouse effect?
It is hard to get concerned when such substantial changes don’t even warrant discussion, much less explanation. Or is there some obvious offset that makes this moot?
——–
Sadly Dr. Miskolczi’s paper and it’s implications are rarely mentioned here, for that aspect of which you speak is probably why increased co2 has had little effect in reality (or it least it hasn’t had any measureable effect in the last 60 years). The slight warming came from some other reason and that is the real mystery, what other reason.

George E. Smith
February 28, 2011 3:12 pm

Well some people like a wavelength Horizontal scale, and some people like a wave number scale.
The AGW types, like the frequency scale, because that puts the CO2 frequencies near the peak of the curve; which creates the illusion that CO2 is far more important than it is. CO2 in the 606 to 741 wave number range looks much more impressive than the water bands beyond 1250 cm^-1, where the thermal emissions are only half the flux values as at the CO2 peak.
Well the width of the water bands in wave numbers is a lot more than double what it is for CO2, so water still wins, although it is not as apparent on their frequency graphs. It may be true that frequency, which relates more directly to photon energy, is the right way to do it; but then Wien’s displacement law is always stated as a product of wavelength and Temperature, and the Planck function is often plotted as a function of the single variable lambda.T.
I don’t like Ira’s wiki graph, because it creates the incorrect impression that the earth thermal emission spectrum is the same amplitude, as the incoming solar spectrum; which it is not.
The area under the solar spectrum graph is four times the area under the thermal radiation spectrum, and the spectral width of the thermal spectrum, is 20 times that of the solar spectrum, so the actual amplitude of the thermal spectrum should be about 80 times smaller than it is.
The solar spectrum goes from 0.25 to 4.0 microns for 98% of the energy, while the thermal spectrum goes from about 5.0 to 80 microns for the same 98% of the energy. Even if you equate those two energies, the thermal spectrum amplitude should be 20 times lower than plotted.

George E. Smith
February 28, 2011 3:23 pm

jknapp; it is a misundertanding on your part. The wavelength specific nature of say CO2 or H2O is a function of the absorption modes of those molecules, which relate to specific mechanical resonances of the molecules themselves.
BUT most of those excited molecules DO NOT get a chance to re-radiate, that photon, and return to the unexcited state. The time interval between molecular colliwsions is a few nanoseconds; but the lifetimes of the excited states, can be microseconds to milliseconds; so the energy is lost in collisions, before the molecule gets a chance to re-radiate. That thermalization heats the whole atmosphere; the N2, the O2, the Ar, and anything else; and it is that mixture of gases, at somer average temperature in the 250-300 K range, that is the source of the atmospehric emitted thermal continuum spectrum, that is not related to specific molecular energy levels, but only to the Temperature of the gases; whcih determines the dynamics of the collisions, and the resulting chaotic accelerations of the colliding molecules, and the electric charges they contain.
So the atmosphere does radiate a black body like thermal spectrum, and the presence of the gHG molecules simply means that there will be bands of that continuum emission, that are also captured by the GHG molecules, as well as the emissions from the surface.
The only function of the GHG molecules is to heat the atmospheric gases; along with all the other mechanisms that are heating it. After that, the GHG molecules serve no function in the climate process whatsoever.

February 28, 2011 3:39 pm

A nit pick; the ‘curves’ (from wiki) in that first figure all indicate to have the same peak amplitude (in reality they do not, of course). This is in the same category of drawing sine waves using half-circles from a drawing template which yield a ‘slope’ that is seemingly infinite as (delta y / delta x) -> infinity as x -> 0. (Never mind that the same that amplitude scale seem applicable to both solar and earth intensities … one may click my name and see the 2nd image down to see something drawn to scale relating sun and earth intensity. )
Using this depiction does not convey graphically the idea that ever-greater amounts of energy ‘escape’ through the atmospheric window (out to space or to the ‘great beyond’) as the temperature rises.
Please, correct me if I am wrong …
.

Edward Bancroft
February 28, 2011 3:42 pm

In your animated diagram what happens to the downward re-emitted 7μ radiation when it reaches the earth surface? I believe that what happens is that it may emitted again as 7μ IR radiation, or at a longer wavelength such as a photon in the 10μ band. In the former case it will have a high probability that it will be absorbed and downward emitted again, and in the latter case it will be lost to space.
Thus the 7μ band sees not an equilibrium of up and down radiation flux, but a continuous stream of loss to 10μ. This would cause more energy to be lost than in your model.

February 28, 2011 3:45 pm

George E. Smith February 28, 2011 at 3:23 pm :

So the atmosphere does radiate a black body like thermal spectrum, and the presence of the gHG molecules simply means that there will be bands of that continuum emission, that are also captured by the GHG molecules, as well as the emissions from the surface.

I’ll wait to see how this is adjudged.
(IR Spectroscopy explaining spectral response regarding gas molecule vibrational modes would seem to indicate otherwise.)
.

Iskandar
February 28, 2011 3:50 pm

This graph, about the atmospheric absorption, is from the 1970’s. Could anyone provide a recent one? Just to compare things.
Thanks in advance.

Dan in California
February 28, 2011 3:53 pm

jknapp says: February 28, 2011 at 3:01 pm
Thanks Ira. Interesting post. A couple of questions, which will undoubtedly demonstrate my lack of physics knowledge. I thought that atoms emitted photons based on quanta specific to that atom. As such the H2O and CO2 molecules will absorb and emit only specific wavelengths.
————————————————–
This is true at low pressures, such as inside a fluorescent light bulb or a gas laser. At higher pressures, such as atmospheric, the molecules interact with each other and smear the lines into bands. Think of it as trying to make a perfect baseball pitch with 3 people bumping into you.

DCC
February 28, 2011 3:59 pm

etudiant said:

Relative humidity in the upper atmosphere (300mb level) has fallen from around 55% in 1950 to about 45% now.

Can you provide a reference for that?

Philip Peake (aka PJP)
February 28, 2011 4:02 pm

Now this is much better than the bouncing balls 🙂
Now we are getting somewhere.
To simplify what is going on, we have very little impediment between the Sun’s radiation and the earth. But there is a layer of absorbent material between us and space at the frequencies at which the earth re-radiates its energy.
This absorbent layer consists mainly of water vapor (H2O), and a little CO2.
These gases absorb the radiation (heat) and themselves become warm. Like all insulators, all they do is delay the loss of heat. No insulator stops the loss of heat, it just delays it. In this case it is delayed by the many, many absorption re-emission, absorptions of the earths radiated energy.
The important thing about this is told by the first graph. Look at the words on the right-hand side: “Total absorption and scattering…”.
What that means is that adding any more H2O or CO2 will have zero effect, because all the radiation from the earth is ALREADY absorbed by these gases.
The only way that loss of heat can be reduced is to make the insulating layer thicker (increase the depth of the atmosphere). I have never heard any claim that this is what additional CO2 is doing.
In fact, the only way CO2 can have any significant effect is by the mysterious “forcings”, supposedly pushing more H2O into the atmosphere … but see above .. the absorption by H2O is already 100%, so unless (again) there is a claim that the increased H2O is increasing the depth of the atmosphere, the means by which this insulating layer is becoming more effective escapes me.

Olavi
February 28, 2011 4:03 pm

Thanks for intresting post. Have you considered that Quiet Sun makes atmosphere to shrink and as we know from sound waves, low frequency sound waves go easier through thinner wall as well shorter waves starting to go through if wall is thinner. I believe that IR acts same way. Is there any measuremet of IR behavior between situations when atmosphere is puffed up or shrinked down? Collapse of thermosphere can make diffrencies to athmosphere’s density at least down to 30 km altitude. I believe, it can have measurable effects to atmospheric temperature.

DCC
February 28, 2011 4:03 pm

Fred Souder said:

It has recently been discovered that our atmosphere is being continuously shed by the solar wind, and replenished by volcanism.

Could you give us a reference for that?

Alex
February 28, 2011 4:05 pm

If absorption of the re-radiated energy by water vapour is logarithmic akin to that of CO2, and the concentration of water vapour in the atmosphere is genrally already several orders of magnitude higher than CO2, how can an increase in absolute humidity have any more than a miniscule effect? It seems the models rely on this increased humidity feedback to amplify the small incremental warming from CO2 to a significant several degrees C. As we know from the characteristics of CO2 the bulk of the so called “damage” is done within the first 100ppm. Is water vapour any different?

Iskandar
February 28, 2011 4:07 pm

And most importantly, if the backradiation phenomenon does exist, it will change the transmission windows. At maximum absorption, the atmosphere will beome translucent due to back radiation. Which, to my humble opinion, is in contradiction with the first law of thermo.
Be free to correct me if I am wrong.

kbray in california
February 28, 2011 4:07 pm

Another little thought visualization for CO2 in the atmosphere.
Let a backyard swimming pool represent the atmosphere.
Let the air above it represent outer space.
A black colored ball bobbing in the water represents CO2.
The black ball is calculated by size in relation to the pool for its appropriate ratio as per CO2 in the atmosphere.
The sun comes up and warms the water, and the black ball is a heat sink due to its color. The heat absorbing ability of the black ball represents CO2’s greenhouse effect.
At the end of the day, heat absorbed by the water is released to the air, representing atmospheric heat released to space. Heat absorbed by the ball is released to the water representing CO2’s heat retention/reflection in the atmosphere.
How much is that tiny ball bobbing in the pool going to maintain the pool temperature?…. I do not think it is even measurable. The dynamics of the entire pool are too great to overcome by this little ball and reach a temperature equilibrium regardless of the little ball’s efforts.
A black ball representing the man made CO2 would be even more insignificant.
CO2 is treated in AGW articles like it is a nuclear heat source of magic abilities to retain/conserve heat. I don’t buy it.
I do not believe that CO2 in tiny amounts can heat the earth as claimed. Mars is almost 100% CO2 and it’s still too cold for us to live there… where is the runaway greenhouse effect on Mars?
A simple visualization like this displays the obvious that it is physically impossible for CO2 to have any major effect on earth’s temperatures as claimed.

EdH
February 28, 2011 4:07 pm

Interesting post. Along these lines, a recommendation:
I’m an mild AGW skeptic myself (like Willis; it’s not a religion and you could convince me otherwise with good evidence), but I’ve been following “The Science of Doom” blog recently (found via a link on Climate Audit):
http://scienceofdoom.com
The author has been carefully (and I’d say honestly) and at great length going through the physics.
Worth a good look, IMHO. Currently he’s discussing the better textbooks on the physics of the atmosphere. I bought Taylor’s book a couple of months ago and have just started to go through it (starting my taxes early this year has put it mostly on hold).
Greenhouse posts:
“Understanding Atmospheric Radiation and the “Greenhouse” Effect”, parts 1-5 will reward the patient reader.

Jay Davis
February 28, 2011 4:09 pm

Nice visual aid. I’m not a scientist, however I’ve had extensive experience operating in jungle and desert environments. My direct observations have been that in the jungle, where humidity is very high, it stays hot when the sun goes down. Almost the whole night through. In the desert, where humidity is very low, it cools down rapidly when the sun goes down. At altitude it can get damn cold. Now I’m making a WAG here, but I assume that the atmospheric CO2 level is the same in both environments. Therefore, it is the humidity, atmospheric water vapor, that is the moderating element and CO2 does nothing. So in order for CO2 to contribute to global warming, it requires the sun. And I am given to understand that radiation from the sun only acts on water vapor and CO2. The other atmospheric gases, mostly nitrogen and oxygen, do not do anything, they absorb no radiation of any wavelength nor reflect ant radiation of any wavelength. Not being a scientist, for the sake of argument, I’ll accept that. But what I have a very hard time accepting is how a trace gas, CO2, can have any effect on anything.

wayne
February 28, 2011 4:11 pm

Ira, I’m going to give you a big slap on the back. Well done!
You are the first scientist posting here that has portrayed the whole process (well ignoring some minor details) in such clarity and showing the whole atmosphere, all atoms and molecules, radiating as I always thought was correct. Bravo!
Now all you have to do is reassure me one last time that you are sure all matter radiates, for that has been my one struggle for nearly 15 months. I sometimes feel I have been led, lied to and swindled out of some of my forty year understanding of physics, constantly being reminded, no told, from all sides that O2, N2 & argon do not and cannot radiate, even when combined as an atmosphere. (never really bought that)
Now the only thing I don’t seem to know is the proper division of rates of overall radiation from the bulk atmosphere and how much might actually reverse thermalize back to the GHG gases with most molecules just thermalizing again and a small fraction actually radiating. But that is just a minor detail. Thank you again Ira (and davidmhoffer for listening).

richard verney
February 28, 2011 4:16 pm

Solar input (in the sense of the amount of energy being received at the top of the atmosphere from the sun) may be costant although there may yet be processes that we have yet to understand.
However, the mere fact that the energy from the sun is constant does not mean that the amount of energy received at ground level has remained constant. There only needs to be slight variations in the amount of clouds (their area, shape, reflectivity) to result in changes to the amount of energy received by the oceans and the land. A change in the pattern of the clouds of just 1 or 2% could account for all the observed warming. We have no real historical data of cloudiness.
The point raised by etudiant February 28, 2011 at 2:18 pm is a good point. I would like to hear some more on this and the effect that this ought from a theoretical point of view had on warming/cooling observed at the surface..
Measuring the temperature of the oceans is probably the best metric for assessing whether there is any warming. This is becuase the oceans account for about 70% of the surface area of the globe and they contain (ignoring the core) approx 99% of the stored global energy. Further, a change in temperature in the oceans can be converted to joules and thus the heat content is know. Land based air temperature record does not measure energy since it does not also include data for humidity/moisture content.
i disagree that measuring ocean temperature can be used to assess sensitivity. In my opinion, measuring the heat content of the oceans cannot necessarily be used to assess sensitivity since a slight change in the amount of cloudiness has a significant impact on the amout of solar radiation being received by the oceans. Unless we accurately know the total amount of clouds and their pattern, we will not be able to rule that out as the source of any observed warming (or cooling).

JAE
February 28, 2011 4:19 pm

“A real greenhouse primarily restricts heat escape by preventing convection while the “greenhouse effect” heats the Earth because “greenhouse gases” (GHG) absorb outgoing radiative energy and re-emit some of it back towards Earth.”
Yeah, that is the theory. But NOBODY has yet been able to show that the “greenhouse effect” actually “heats the Earth,” as stated here. I.e., there is absolutely NO empirical evidence of this, only a simplistic analysis of what PART of the system (the radition) does, WITHOUT ANY CONSIDERATION OF WHAT ELSE IS GOING ON that might affect the putative heating. Does convection increase due to additional backradiation, thereby “erasing” some/all of the heat (the consistency of the lapse rate seems to suggest this is so)? Why are the temperatures in areas which have the highest amount of greenhouse gases at any given time (tropics) never much above 30 C (probably evaporation but does that counter the warming of the GHE? ) Any actual heating from the “atmospheric greenhouse effect” may vanish in the same way that the real greenhouse effect does when the windows to the greenhouse are opened. Radiation is only PART of the system, folks.

James Sexton
February 28, 2011 4:20 pm

“Most Sunlight is in the visible band from 0.38μ (which we see as violet) to 0.76μ (which we see as red), which is why our eyes evolved to be sensitive in that range.”
======================================================
I probably would have come away with a more complete view of your posting had you not included this little statement. I read through your post, and most of it, I agree with.
But, towards the mentioned statement………….. That’s beautiful, you’ve managed to refute Newton without expressing how or why. But, gleaning what I can from this statement, our eyes evolved to seeing something we couldn’t otherwise see…………..because of the entire specie’s collective inherent knowledge? And thank God……errrr, uhmm…..thank Gaia…..errr…..thank evolution for giving that to us, else we’d be navigating in a manner such as bats!

Katherine
February 28, 2011 4:26 pm

The portion of the Earth at about 310ºK radiates energy towards the Atmosphere at slightly shorter wavelengths than that at about 210ºK, but nearly all Earth-emitted radiation is between 5μ to 30μ, and is centered at about 10μ.
So, when the Earth warms, it radiates less longwave radiation in the bands absorbed by CO2 and when it cools, it radiates more longwave radiation in the bands absorbed by CO2? Meaning when the Earth warms, more longwave radiation escapes, allowing the planet to cool, and when the Earth cools, more longwave radiation is reflected, allowing the planet to warm? Do I have that right?

RJ
February 28, 2011 4:26 pm

Fred
“I would guess that the vast majority of energy leaves earth by radiation”.
It would leave the outer atmosphere by radiation. But Charles R Anderson in STSD Ch 20. In the denser, lower altitude atmosphere, most energy transfer is due to gas molecule collision etc.
I don’t know but it seems even the experts do not agree on this.
Most accept the GHGT (even sceptics) but the more I read on this topic the more I’m of the view that the entire GHG theory is flawed. But I’m not an expert.

Myrrh
February 28, 2011 4:31 pm

I’m really at a loss to understand any of this. How on earth does Visible light and near short wave heat the Earth?

kbray in california
February 28, 2011 4:32 pm

Another thought…
Suppose I bought a container of CO2 for carbonated beverages and boosted the CO2ppm from 390 to 1000ppm in my apartment air.
Will the winter sunshine boost my apartment temperature by say 10 degrees F due to the greenhouse effect of the CO2 ? Doubtful…
I’d save a lot on my heating bill if that would work… if it really did work, we’d all be doing it.

Brent Hargreaves
February 28, 2011 4:34 pm

I just tried jotting down, step by step, a sequence of events beginning with evaporation from the sea surface, absorption of latent heat, subsequent condensation at altitude into opaque liquid droplets and the release of selfsame latent heat.
I soon got bogged down with considerations of cloud opacity, absorbtion and reradiation of IR from above and below by day and by….. (gasp)… and this is purely descriptive stuff; I didn’t reach the next step – attempting the numbers.
This stuff is com-pli-cated! Could it be that this complexity frightens the bejaysus out of even professional climatographers… with the consequence that they each concentrate on (or hide away in?) some narrow aspect of climate but shy away from contemplating the mind-bogglingly big picture.
Is the Global Warming scare is a ‘fragmentation failure’? When the house of AGW cards collapses. will they in the postmortem say, “I was just concentrating on my little patch. I thought that others were ensuring that the jigsaw pieces made up a coherent whole!”
Here’s a ficticious entry to Wikipedia 2061: “With the benefit of hindsight we see that clouds – messy, irregular, fuzzy and inconvenient – were hiding fullsquare in the blindspot of millennium climate science. A key feature of the Earth’s thermostat, the absence of clouds from the IPCC’s analysis allowed the notion of unstable equilibrium – the ‘Tipping Point’ fallacy advanced by faded politician Al Gore – to terrify the public. When, finally, clouds were ‘discovered’ the bottom dropped out of the global warming market. The worldwide celebration of Gore Day is an enduring reminder of those dark days; a warning to future generations to be on one’s guard against end-is-nigh merchants, especially those with expensive haircuts and silver tongues.”

Tim Folkerts
February 28, 2011 4:34 pm

First of all, I like the post in general — it seems to provide a fairly effective visualization.
Fred Souder says: February 28, 2011 at 2:31 pm
Are there any experiments which detect the incoming re-emitted radiation from the atmosphere?

I googled images for “outgoing infrared spectrum” and found this: http://www.skepticalscience.com/images/infrared_spectrum.jpg
It should the spectrum looking up from somewhere in the arctic on a clear day and the view looking back down from 20 km. The incoming radiation would be the re-emitted IR from the atmosphere that you wanted. It clearly shows the 7 um, 10 um and 15 um bands Ira is talking about.

RJ
February 28, 2011 4:38 pm

Jay
The other atmospheric gases, mostly nitrogen and oxygen, do not do anything, they absorb no radiation of any wavelength nor reflect ant radiation of any wavelength.
I’m not sure about this
I think molecules like oxygen. nitrogen and Argon are warmed by convection. They can exchange this energy by convection as they rise or by radiating IR radiation.

Bill Illis
February 28, 2011 4:40 pm

It is the first time I’ve seen an explanation where the energy represented by the specific frequencies absorbed by GHG molecules are transferred to non-GHGs through collision (and then reemitted by the non-GHGs in the atmospheric windows – almost everyone believes the non-GHGs absorb and emit no IR radiation at all – some bad textbooks mis-educated everyone somewhere along the line).
But then, to show this has a real greenhouse effect (an extra 150 watts/m2 at the surface), the numbers have to be crunched taking into account the time lag between absorption and effective emission to space.
The 10 um atmospheric window actually emits at a higher energy level than it should according to Earth’s temperature alone.
Second, if it was a simple process of 1 CO2 molecule absorbs a 15 um photon and then passes that on to 1 N2 molecule which then promptly emits that to space in the atmospheric window at 10 um, there be no greenhouse effect at all.
The entire process would only take 0.001 seconds for ALL the photons to escape to space. Once the sun sets, the atmospheric temperature should fall to -220C within a second.
But the average time the energy represented by a solar photon spends in the Earth system before it is lost to space is 43 hours. It spends time in 5 billion different molecules before it escapes to space on average.
There is much much more going on here which I would love to see explained to my satisfaction.

Dave Springer
February 28, 2011 4:47 pm

@Ira
That wikipedia annotation “15%-30% transmitted” is a crock of sht. 100% of outgoing thermal radiation is “transmitted”. There is no other way for energy to leave the atmosphere and if it all doesn’t leave then the earth’s temperature would keep increasing until was as hot as the sun.
What they mean to say is that 15% to 30% of thermal radiation leaving the surface escapes in a fraction of a second. The rest is delayed to some degree by absorption and re-emission but it too eventually leaves the theater by the only exit possible.
A theater makes an excellent analogy. At the end of the movie there’s a rush for the exits. A few people make out the door without delay. Then a line forms and things slow down. People start crowding each other and if it’s too slow they start pushing and yelling which tends to speed up the line. The earth’s surface temperature rising in response to the delay caused by absorption and re-emission is like the people leaving the theater pushing and yelling to get the line moving faster.
Well maybe not a great analogy but I never give up hope that some damn thing will make sense. You’d think this was rocket science by all the confusion and misunderstanding but in reality it’s about as complicated as attic insulation and can
described so the proverbial bartender can understand it. People seem to just refuse to accept the simple facts of the matter and the more they think they know the bigger and more sciency the words they use in their convoluted alternate explanations.

Stephan
February 28, 2011 4:48 pm

For Leif Svaalgard to ruminate upon..
http://www.halesowenweather.co.uk/cet_sunshine.htm

etudiant
February 28, 2011 4:49 pm

To DCC
The data is here: http://www.climate4you.com/
Click on the Greenhouse Gas section on the left and scroll down to get atmospheric humidity trends since 1948.
Overall, that site is a fabulous resource, with lots of interesting nooks and crannies.

cal
February 28, 2011 4:58 pm

Ira, I like the description overall but I do not like the Wiki graph of the outgoing infrared. It is technically correct in that it shows the likelihood of a photon of a particular wavelength being emitted by the earth and then passing through the atmosphere without being absorbed. However it might give the impression that it is the spectrum radiated into space. In practice the radiation into space is pretty much the black body spectrum you would expect for a body at about 290K with reductions at particular wavelengths particularly between 5 and 8 micron and between 14 and 18 micron as you describe in your text. Photons of these wavelengths can only be radiated into space by water and CO2 molecules at very high altitude since emissions lower down are absorbed. The lower temperatures at these altitudes acount for the reduced emissions.
George E Smith. I do not think I agree with your last point assuming I understand it properly. You state “The only function of the GHG molecules is to heat the atmospheric gases; along with all the other mechanisms that are heating it. After that, the GHG molecules serve no function in the climate process whatsoever”
As I have just explained CO2 and H20 are the main sources of radiation into space from the troposphere and indeed CO2 is the main source of radiation from the the stratosphere which is heated directly by the absorption of UV from the sun mainly by ozone. As I read it you seem to imply that the greenhouse molecules pass all their energy to the O2 and N2 molecules which then radiate into space. However they can’t since there is a law which says that a bad absorber cannot be a good radiator. In reality the energy is partitioned amongst all the molecules but the CO2 and H20 molecules radiate into space and cool the upper troposphere and tropopause. So the greenhouse gasses warm and they cool as well. That is the nature of thermodynamics.
Further to this point there have been several comments to the effect that you cannot have energy passing from a cooler to a warmer body. This is not true. The rule is that you cannot have a net energy transfer in this direction but there is always energy being radiated from any body above absolute zero. So greenhouse molecules do warm the earth. It is just that they are being warmed by the earth at a greater rate. So the nett flow is upwards.

rbateman
February 28, 2011 4:58 pm

I would ask what happens at night?
My initial guess is that the 7u/10u/15u process repeats itself under a law of diminishing returns until day arrives.
What is most interesting is that the 7u bandwidth is only hindered by H20 for outradiating.
So, only 1/2 of the reflection back to Earth has CO2 involved.
2nd question: What % is C02 involved in the 15u bandwave, assuming the two worst cases: Maximum humidity and minimum humidity?

kuhnkat
February 28, 2011 4:59 pm

Ira,
” The ~7μ and ~15μ generated by the heating of the air also emerge from the top or bottom of the Atmosphere, but there are fewer of them because they keep getting absorbed and re-emitted, each time with some transfered to the central ~10μ portion of the longwave band.”
Could you give more details as to what shifts the energy into the ~10μ window. Is this due to net out from the surface of the absorbed back radiation or are there other effects??

Theo Goodwin
February 28, 2011 5:01 pm

Really good post. Really good questions in some comments. The questions take us exactly to the crucial issue: what are the physical hypotheses which explain what CO2 does to increase climate sensitivity. There will be several such physical hypotheses, of course. What seems best understood is that changes caused in clouds by the additional CO2 will have an impact on climate sensitivity. However, we also understand that there are no physical hypotheses which explain the expected or imagined change in cloud behavior. There will be some day, after the needed scientific work is done. The other needed physical hypotheses are in worse shape. We do not have so much as good hunches about the phenomena in question, unlike the case of clouds. The science is in its infancy. Any Warmista who denies this surely must be challenged to produce the relevant physical hypotheses. Short of those hypotheses, the claim that someone has scientific reasons for attributing warming to manmade CO2 are as empty as the claim that straw can be spun into gold.

wayne
February 28, 2011 5:01 pm

George E. Smith says:
February 28, 2011 at 3:23 pm
The only function of the GHG molecules is to heat the atmospheric gases; along with all the other mechanisms that are heating it. After that, the GHG molecules serve no function in the climate process whatsoever.
—–
George, are you positive of including the word “only” in your statement and not “one of”. I read from those words that you don’t think thermalization can run in reverse the way the equatuion reads with symmetry. Like when the atmosphere is warmer than it should be compared to the surface and at dusk or night. I have always viewed GHGs can either heat or cool depending on the exact conditions. Any clarification?

kuhnkat
February 28, 2011 5:01 pm

Bill Illis,
” Once the sun sets, the atmospheric temperature should fall to -220C within a second.”
Even without GHG’s we would still have stored energy in the water and surface of the earth.

RJ
February 28, 2011 5:02 pm

Bill
almost everyone believes the non-GHGs absorb and emit no IR radiation at all
Bad textbooks. It seems that way. Because otherwise how would say Nitrogen release energy. Some would be by convection by surely not all. Otherwise it would have to collide with water vapour or CO2. Which might not happen. And then what as it rises higher and higher.

February 28, 2011 5:08 pm

I’ve been trying to think of the perfect experiment to demonstrate the effects of “back radiation”. Here’s what I came up with.
Put a pot on the stove. Fill it with a couple of gallons of water. Put in a thermometer. Heat it up to boiling. Turn off the heat. Every 10 minutes, make a note of the temperature as the water cools back toward room temperature.
Refill the pot to get the same volume of water. Heat to boiling. Turn off the heat. Slowly move a cookie around the room–put it anywhere you like, but not over the pot because you don’t want to restrict convection in any way (we want to measure the influence of radiation, not convection). The cookie will “back radiate” into the water. Every 10 minutes, make a note of the temperature as the water cools. Voila! The difference between the two temp series as the water cools will be your radiation effect.
The mass of the water and the mass of the cookie are supposed to represent the relative thermal capacities of the earth’s surface and rarefied CO2.
It might be more appropriate to use a Cheerio or a speck of dust, I don’t know.

Phil's Dad
February 28, 2011 5:32 pm

Katherine 4:26
So, when the Earth warms, it radiates less longwave radiation in the bands absorbed by CO2 and when it cools, it radiates more longwave radiation in the bands absorbed by CO2?

I think you are right except that the longwave radiation that would subsequently move beyond the shorter end of the 10um atmospheric window would be absorbed / re-radiated by H2O instead. What we can say is that, all other things being equal, as the earth warms CO2 becomes a less significant GHG.
James Sexton 4:20 pm
Eyes evolved by pure chance, doubtless along with a whole load of other “useless” sensors and probably at all sorts of different sensitivity / frequency ranges. Natural selection favoured those who could see. See?
(It is interesting to speculate on what other senses could be close to mutating into something useful)

DccMartyn
February 28, 2011 5:52 pm

Ira, can you explain this to me. Approximately 6% of the energy spectrum, hard uv, is absorbed by the upper atmosphere, mostly by Ozone.
Now this heat must be reradiated, so half must go down. I never see this heat in any of the box figures, but it can’t just disappear.
So where does this heat go and in what form does it leave or enter the Earths atmosphere?

D. J. Hawkins
February 28, 2011 5:52 pm

kbray in california says:
February 28, 2011 at 4:07 pm
Another little thought visualization for CO2 in the atmosphere.
Let a backyard swimming pool represent the atmosphere.
Let the air above it represent outer space.
A black colored ball bobbing in the water represents CO2.
The black ball is calculated by size in relation to the pool for its appropriate ratio as per CO2 in the atmosphere.

I think your counter analogy is missing a few elements. During the day, the black ball absorbs “high grade” heat and tranfers it to the water by convection/conduction. At night, “low grade” heat is transferred to the ball from the water by convection/conduction and is radiated out to “space.” All things being equal, add more balls to the pool and you can heat the water to a higher temperature. In point of fact, people actually do this to help their pools warm up in early spring. You just add a pool cover to reduce re-radiation at night.
Now, I’m not claiming that bumping the CO2 from 350ppm to 1,000ppm is going to roast us alive. Far from it. But if someone could point me to a post on the logarithmic behavior of GHG’s in the atmosphere, I’d appreciate it.

Jim D
February 28, 2011 5:53 pm

The main thing to correct in this explanation is that the CO2 and H2O will not emit in wavelengths that they don’t absorb, so none of the 10 micron photons reaching space will have been emitted by the CO2 or H2O gas. Clouds can emit at all wavelengths, but not these gases. I believe Miskolczi has a similar misconception that the window region will somehow show increasing GHGs, when it can’t because they don’t emit there.
The other quibble is related to the idea of these photons heating the atmosphere. In fact, the troposphere is mostly heated by convection from the surface with radiation having a net cooling effect, so the atmosphere as a whole emits more photons to space than it gains from the ground.

KevinK
February 28, 2011 6:11 pm

Ira, with respect, a comment;
You wrote (in part);
Regarding the incoming (mostly) visible radiation;
“On the left side:
….. (portions omitted for brevity)
The remainder is absorbed by the Surface of the Earth, warming it.”
Regarding the outgoing IR radiation;
“On the right side:
(1) The warmed Earth emits longwave radiation towards the Atmosphere.”
Both of these are entirely correct. But you are missing one small detail, if I might be so bold as to supply a minor edit;
“On the right side:
(1) The warmed Earth emits longwave radiation towards the Atmosphere.” This subsequently causes the Earth to COOL by an amount EXACTLY equal to the energy contained in that packet of emitted IR radiation.
And then of course the reemitted radiation from the gas may return to the Earth thereby warming it again. But this warming must be less than the cooling when the IR radiation left. Thus, no “net energy gain” and no ”higher equilibrium temperature”.
You cannot simultaneously retain energy and also emit it. You can accumulate energy and emit it later thereby de-accumulating it.
I know it is hard to believe that 30 years of very hard work by climate scientists could have such a major flaw. But sometimes folks get so far into the details of the work that the forest is no longer visible since they have been staring at the tree bark.
Nice graphics.
Cheers, Kevin.

HankHenry
February 28, 2011 6:15 pm

If I understand rightly, while to our eye air is transparent, in the longwave earth’s atmosphere is a very murky and foggy kind of thing. I also believe that the greenhouse effect is due to the stairstep kind of transit that longwave radiation coming up from the earth has to go through to reach the surface from which it can be emitted to space. What I have yet to see is how the calculation is done that figures the transit time. To me this would be an important calculation because the longer the transit the greater the heating of the atmosphere should be. Is this something that is dealt with in the field of statistical physics? It would also be interesting to understand in microscopic detail what happens when shortwave radiation hits a solid surface – or for that matter a liquid surface since the earth is 71 % sea.

Dave Springer
February 28, 2011 6:39 pm

Bill Illis says:
February 28, 2011 at 4:40 pm

It is the first time I’ve seen an explanation where the energy represented by the specific frequencies absorbed by GHG molecules are transferred to non-GHGs through collision (and then reemitted by the non-GHGs in the atmospheric windows – almost everyone believes the non-GHGs absorb and emit no IR radiation at all – some bad textbooks mis-educated everyone somewhere along the line).
But then, to show this has a real greenhouse effect (an extra 150 watts/m2 at the surface), the numbers have to be crunched taking into account the time lag between absorption and effective emission to space.
The 10 um atmospheric window actually emits at a higher energy level than it should according to Earth’s temperature alone.
Second, if it was a simple process of 1 CO2 molecule absorbs a 15 um photon and then passes that on to 1 N2 molecule which then promptly emits that to space in the atmospheric window at 10 um, there be no greenhouse effect at all.
The entire process would only take 0.001 seconds for ALL the photons to escape to space. Once the sun sets, the atmospheric temperature should fall to -220C within a second.
But the average time the energy represented by a solar photon spends in the Earth system before it is lost to space is 43 hours. It spends time in 5 billion different molecules before it escapes to space on average.
There is much much more going on here which I would love to see explained to my satisfaction.

Fortunately we don’t have to work through the theoretical quantum physics for every particle in the atmosphere. All we have to do look is look at the surface with a thermal spectrometer from a high altitude and observe the result.
The following is what you see in the infrared spectrum looking upward and downward:
http://www.sundogpublishing.com/fig8-2.pdf
It’s from the 2006 textbook “A First Course in Atmospheric Radiation” by Grant Petty.
Looking downward from 20km over the arctic ocean you can see how much energy is missing in the CO2 absorption band. In the IR window you can “see” right down to sea level which follows the curve of a 265K blackbody. At CO2 absorption frequency of 15um the curve at 265K suddenly drops down sharply to follow the 225k blackbody curve. Using the dry adiabatic lapse rate of 1 Kelvin per 100 meters this gives us an emission altitude of 4 kilometers or about 12,000 feet. At that point absorption and thermalization (transfer of energy to other atmospheric gases) of 15um upwelling radiation by CO2 ceases and it is transmitted directly out to space and follows a colder blackbody curve.
Now, if you reduce the surface temperature of 265K by an amount that’s enough to fill in the hole at 15um (and the other smaller holes in CO2’s lesser absorption bands) to make a smooth blackbody curve at a lower temperature the downward difference is the amount of greenhouse effect by all atmospheric CO2.
CO2 greenhouse effect isn’t linear except for the first 50ppm or so and then it turns into a log curve where additional CO2 has less effect. This is also determined empirically by taking actual measurements of absorption in a laboratory column of gas so it doesn’t rely on theory. I can look up that curve too and have posted a link to it before but don’t have it handy and don’t feel like searching for it again.
The bottom line when the numbers are crunched on the empirical data is a 1.1C increase in surface temperature per doubling of CO2 starting from a baseline of 280ppm with about half of that already a done deal in going from 280ppm to 390ppm today. That 1.1C is the IPCC low end “sensitivity” estimate which isn’t a scary number at all and in fact is a great number because if that’s all it is then the slight warming, mostly in the winter in the higher latitudes, is a great boon to agriculture especially when the biological effect of higher CO2 on green plant growth rates and water consumption is taken into consideration. It’s actually moving the earth closer to an optimum climate where I define optimum as that climate which dominated the earth’s history and in which green plants evolved. Naturally we would expect plants to be best adapted to the environment in which they spent the most time evolving and adapting over hundreds of millions of years. Even if you don’t believe in macro-evolution just about everyone accepts micro-evolution and that’s all we’re talking about is micro-evolution.
In order to sex up CO2 greenhouse warming to a point that might make it scary the climate boffins invented, out of whole cloth with no empircal data to back it up, an imaginary “amplification” where a little CO2 warming increases greenhouse warming by water vapor by twice as much. Following that out to its logical end, since warming is warming no matter the source, water vapor warming will cause even more water vapor warming through positive feedback and we get a runaway greenhouse. In the almost sure knowledge that the earth never experienced a runaway greenhouse even with ancient CO2 levels 10 to 20 times greater than today, these anti-science scoundrels insist with a “high level of confidence” that this amplification is real and it’s based on nothing more than faster than expected surface temperature rise in the past few decades which can be TOTALLY explained by multi-decadal cyclic behavior in ocean currents, trade winds, and/or solar magnetic activity causing small global average albedo changes. There isn’t a lick of evidence that water vapor amplification is more than a figment of fevered imaginations. But CO2 greenhouse effect alone IS real and empirically established.

wayne
February 28, 2011 6:49 pm

When looking at http://www.skepticalscience.com/images/infrared_spectrum.jpg link given by Tim Folkerts above, and looking at the spectrum of the surface looking up there appears that the all-atmosphere radiation is somewhere around 5% radiance. You see that 5% especially in the window frequencies between about 8 and 12.5 µm.
That seems to imply that most of the transfer in Ira’s animation after initial absorption is still via thermalization and re-excitation, both directions and is keeping most of the radiance in the GHG absorption/emission lines. Would you roughly agree with that?

Anthony Zeeman
February 28, 2011 6:57 pm

The mass of the earth is one trillion, that’s 1 followed by 12 zeros, greater than the mass of carbon dioxide in the atmosphere. There is no way that an infinitesimal amount of gas could contain enough energy to significantly change the earth’s temperature. Any heating of the earth is by direct absorption of energy from the sun.

jae
February 28, 2011 6:59 pm

Ken Coffman:
“I’ve been trying to think of the perfect experiment to demonstrate the effects of “back radiation”. Here’s what I came up with.”
Well, to repeat myself at least 100 times, here’s another “experiment” to consider:
Atlanta has at least three times as much GHGs as Phoenix in July (both cities are at virtually the same elevation and latitude, so solar energy is not a factor, at least on clear days). Yet it is virtually always MUCH cooler in Atlanta than Phoenix. EVEN AT NIGHT, I keep wondering, WTF?
Now, this can be explained “simply” by the heat lost through evaporation of moisture in Atlanta, which cools their world. BUT, the question still remains: does evaporatative cooling negate/minimize/marginalize the radiative effects of GHE? If so, who gives a damn about the putative increase in CO2???
It is really weird that I have never got a sensible answer to this question, despite asking it for about 4 years now…

February 28, 2011 7:00 pm

Bryan says:
February 28, 2011 at 2:52 pm
“Your graphs are completely misleading. They show that the intensity of the Solar Radiation as being equal to the Earth surface IR upward radiation.”
The curve seems to depict atmospheric transmissivity rather than quantitative energy transfer, despite its label.
“Further the colder atmosphere cannot heat or “warm” the warmer Earth Surface.”
The colder atmosphere still radiates IR back down, contributing to the total inflow. It’s the net transfer that should be considered.
“All it can do is to slow to some extent the heat loss from the surface.”
Yes, that’s how it works. But the warmists would rather sell you a tipping point with catastrophic thermal runaway, when in fact CO2 is already so close to its maximum effectiveness (critical mass if you like) that increasing it will have negligible further effect.

bubbagyro
February 28, 2011 7:08 pm

This is what theoreticians are really good at. I know, I have had to deal with them, as a pragmatic, applied scientists for years. Once they almost talked me out of one of my best inventions, that now saves lives worldwide. Not boasting, just saying. We found out much later, after I put my career on the line, what the key neglected variable was.
What modelers are good at is simplification, actually oversimplification. The goal is to eliminate as many variables that are unknown, or that compete with the model. We have all seen this in action. Once these are accepted, then the rest plays out like clockwork.
I found, at a cursory glance, a few major omissions and simplifications. By ignoring these, the model simplifies, and seems reasonable. To keep this short, I will mention the first. It is a type of misdirection, as a magician would use. Theoreticians are like magicians—they must oversimplify in order to describe a chaotic and heterogeneous system.
Here goes. Did anyone pick up that the “average” incoming radiation is “centered around” 1/2 µ? That is true sometimes, but remember that our sun is a variable M star. What that means is that it has bursts of very short wavelength (very high energy) radiation, like X-rays. Other times, when it gets quiet, the output is switched to lower energy radiation. Including infrared, up to 15000+ nm.
The sun puts out some X-rays—it also generates some infrared.
Defining the solar output range to be between 100 nm and 3000 nm is an arbitrary range, based on averages (as Gaussian distributions). There is an infrared component of incoming solar radiation that is not only reflected, but also absorbed by CO2 and other molecules, and then reradiated as lower energy radiation. The higher in the atmosphere this happens, the more is lost back to space.
CO2 absorbs light primarily in the IR wavelength, but it is not totally transparent to other wavelengths. So the model has another assumption.
Other energy from the sun, such as plasmas, and particles are very important. Especially protons. Protons can protonate CO2, and other molecules to form formic acid and other species.
Etudiant mentions water. Water vapor also reacts with CO2 to form carbonic acid, that can go on to do other chemistry, besides being the king at absorbing almost all wavelengths of incoming and outgoing radiation. Water is the boss, not the secondary actor.
CO2 is generated on the earth’s surface. It becomes more dilute as it diffuses upward. The models, similar to Ira’s, assume it is a narrow band. This is not true. The very dilute CO2 and water even in the stratosphere absorb radiation. The higher that occurs, the more is lost to space. Remember that Mars has 970,000 ppm of CO2 in its atmosphere. But there is not much atmosphere, so there are fewer molecules to absorb. If we halved the CO2 concentration on Mars, it would have a minuscule effect.
BTW, most organisms on the planet are adapted to “seeing” in the ultraviolet. Humans are pretty rare that they cannot. Many animals “see” also in the infrared, so Ira’s argument in that regard has little impact with me. His purpose, it seems, was to for us to focus on the visible range of light to the exclusion of the other incoming wavelengths, in order to help us apprehend his model.
The relationship between the earth and sun is involves the relationship of two variable, chaotic and heterogeneous systems. I like to think of the atmosphere like the Jovian or Saturnian atmospheres, where we see banding and concentration of clouds and compounds, flowing countercurrent to one another. Our atmosphere is invisible to us. The situation with ozone teaches us that gases can be more or less concentrated in different areas of the earth, varying in response to unidentified variables, in a fluid, dynamic interaction.
Notwithstanding these caveats to the models assumptions, Ira does a great job describing the consensus model of the greenhouse effect.

bubbagyro
February 28, 2011 7:11 pm

Oh, no!
I did it again, misspelled my /unbolding. It was only meant for one word.
Sorry.

James Sexton
February 28, 2011 7:14 pm

Phil’s Dad says:
February 28, 2011 at 5:32 pm
James Sexton 4:20 pm
Eyes evolved by pure chance, doubtless along with a whole load of other “useless” sensors and probably at all sorts of different sensitivity / frequency ranges. Natural selection favoured those who could see. See?
(It is interesting to speculate on what other senses could be close to mutating into something useful)
======================================================
lol, It’s all too clear now! Now I can see! Evolution means something was whispering in our soon to be ears that there was something to see out there! Now I’m coming to an understanding! That d.a. Newton……what could he ever logic?

Tim Folkerts
February 28, 2011 7:23 pm

I must disagree with the comments to the effect that N2 & O2 radiate (or absorb) any important amount of IR.
Look at a somewhat similar and more familiar idea – visible light emitted by a Hydrogen atom (the Bohr model covered in freshman chem & physics around the world). It is easy to observe that H only emits very specific energies of light which are “easily” predicted by the quantum mechanics of the orbiting electrons and the allowed transitions between energy levels of those orbits. Photons of other energies are simply not emitted by H atoms. And photons of other energies are simply not absorbed either. Different atoms and molecules will absorb and emit at their own characteristic visible frequencies due to their own electron orbital energies. If you know the energies of the allowed orbits, you can find the energies of photons that can be absorbed or emitted by other gases.
For thermal IR (above a few micrometers), the quantum mechanics is different. This is not taught in freshman chemistry. Here the energies are not related to electrons jumping to other orbits (that takes too much energy), but instead it is related to rotations and vibrations of the molecules (which can happen at the energies associated with IR photons). However, it is an observed fact (supported by theory) that monatomic gases (like argon) or symmetric diatomic gases (like N2 and O2) do not have vibration modes or rotation modes that would allow them to absorb (or emit) IR photons. Just like yellow light is not absorbed or emitted by H atoms, IR is not absorbed or emitted by N2 & O2. (There are some unimportant exceptions – for example O2 or N2 with different isotopes can absorb IR weakly for example. But it is my understanding that this is a very small effect, even given that N2 is MUCH more common in the atmosphere.)

old engineer
February 28, 2011 7:28 pm

Thanks for a very clear explanation of the “greenhouse” radiative effect. As someone who is just beginning to learn about the radiative modeling of the atmosphere, it is greatly appreciated. I’m sure that to many of the WUWT regulars this is very elementary, but to those of us who are just learning, the graphics made it very understandable. It goes in my hardcopy file for sure.
One question. I never see Rayleigh or Mie scattering mentioned, although it is my understanding that, in the atmosphere these equations govern the absorpsion and scattering of electomagnetic radiation from the sun, and the “long wave” radiation of the earth back to space. I am only just aware of Mie theory, having run across it in a project to measure jet engine exhaust particle size.
Can’t these eqations be used to settle some of the arguements of just how much electromagnetic radiation is absorbed and scattered?

February 28, 2011 7:34 pm

PS: Because of Robert Woods 1909 experiment with two miniature “greenhouses”, one with a “rock salt” (i.e., transparent to the longwave IR material) window and the other with a glass window, showing NO MEASURABLE DIFFERENCE in the final equilibrium temperatures in both boxes, we’ve known SINCE 1909 that to ascribe the warming of greenhouses to the allegation of a “one way valve” due to the regular sodium silica glass, is in error.
Real “Meteorological” textbooks for many years have noted this and used the prefered term: “Atmospheric Effect”.
I think the WUWT crowd needs to realize this fact and steadfastly refuse to use the terms “Greenhouse gases” or “Greenhouse Effect”.
Truth needs to win!
Max

Dave Springer
February 28, 2011 7:36 pm

HankHenry says:
February 28, 2011 at 6:15 pm
“If I understand rightly, while to our eye air is transparent, in the longwave earth’s atmosphere is a very murky and foggy kind of thing.”
Yes.
“I also believe that the greenhouse effect is due to the stairstep kind of transit that longwave radiation coming up from the earth has to go through to reach the surface from which it can be emitted to space.”
Yes,
“What I have yet to see is how the calculation is done that figures the transit time.”
Don’t need to do that. We lofted infrared spectrometers with high altitude balloons in clear dry air over the arctic ocean and measured the energy level across the spectrum looking downward.
“To me this would be an important calculation because the longer the transit the greater the heating of the atmosphere should be.”
Yes.
“Is this something that is dealt with in the field of statistical physics?”
Classical (statistical) mechanics and quantum mechanics both. The scale is classical since the wavelength of thermal IR spans billions of molecules at once in the troposphere where all the action takes place. Quantum explanations get truly bizarre. But again there’s no need to use theory when you have empirical observations. It’s like trying to calculate the acceleration of gravity by theory and just measuring how fast a lead ball falls by dropping it from the Leaning Tower of Pisa.
“It would also be interesting to understand in microscopic detail what happens when shortwave radiation hits a solid surface – or for that matter a liquid surface since the earth is 71 % sea.”
Interesting yes but again it’s an easy empirical measurement. The ocean absorbs practically every bit of sunlight that reaches the surface and penetrates to a depth of about 300 meters give or take depending on turbidity. At low angles it begins to reflect a significant portion of incident light but low angles only occur when the sunlight is weak to begin with (near dawn and dusk and at very high latitudes).
Clouds however also cover an average of around 70% of the earth’s surface and they can reflect anywhere between 15% to 85% of the sun’s light directly back out into space. Average albedo of the earth isn’t known to an acceptable margin of error with estimates ranging a few percent above and below 35%. Every percentage point difference is a few degrees warmer or colder surface temperature if the difference is lasting across a number of years. With a marginal exception for seasonal NH/SH difference due to snow cover it’s assumed to be a constant value in the models and different models just pick a number that works out best for fitting hindcast global average temperature with measured past global average temperature. In other words albedo is not just a fudge factor in the climate models but rather a damn big fudge factor that dwarfs any change that anthropogenic CO2 can possibly bring about.
This is why the hypothesis that galactic cosmic ray intensity changes result in more or fewer clouds and changing albedo. GCRs are modulated by both solar magnetic field, which is largely unpredictable in strength except for generalities associated with 11-year sunspot cycle and is also modulated by unpredictable events like nearby supernovas, and by more predictable very very long slow changes in intensity due to the solar system traversing spiral arms of our galaxy and wandering above and below the galactic plane in cycles lasting tens and hundreds of millions of years.
Quite frankly it really appears GCR intensity is The Big Kahuna when it comes to global average temperature variations. The latter half of the twentieth century saw the most intense solar magnetic field (by sunspot number proxy) in the past 400 years since sunspot records began. This would have resulted in fewer GCRs, fewer clouds, lower average albedo, and surface warming from the lower albedo.

Dave Springer
February 28, 2011 7:43 pm

Oops. Saw a mistake in my last comment. Sunlight penetrates the ocean to roughly 300 feet not 300 meters. That would be 100 meters (give or take depending on turbidity) before it gets inky black. It sucks to be one of those strange people (Americans and Brits) who learnt English units of measure in our youths and has had the rest of the world pressuring us into going metric. I try. Sort of.

kbray in california
February 28, 2011 7:47 pm

[[[ D. J. Hawkins says:
February 28, 2011 at 5:52 pm
… All things being equal, add more balls to the pool and you can heat the water to a higher temperature. In point of fact, people actually do this to help their pools warm up in early spring. You just add a pool cover to reduce re-radiation at night. ]]]
If we covered the earth in a pool cover, the heat increase would kill us in short order.
That would create an environment similar to a real greenhouse which becomes scorching in the summer sun and use water spray, windows, and fans to cool down. They can be deadly for plants and people trapped in them in the summer if they are not managed properly. A pool cover is not an accurate representation of CO2.
My point with the black balls is that the ratio to the volume of water is miniscule… they cannot have much effect due to the small quantity…. same as CO2 is only a trace gas in the atmosphere. The black balls should actually be drifting under the water to be a more accurate representation of CO2 floating in the atmosphere. You are creating a non-representative condition by covering the surface of the pool with black balls, (and also interfering with surface cooling by radiation/evaporation) and…
1) That is also creating an overrepresentation of CO2. and..
2) CO2 does not float at the top of the atmosphere, but is homogenized in.
I suggest again that there are not enough black balls floating around in the pool to make any measurable change in water (atmospheric) temperature.
I realize this is not a perfect analogy. CO2 purports to reflect certain wavelengths back to the planet. I visualize CO2 in the atmosphere like a screen door on a submarine…. Some of the energy waves will get reflected back, but there are so many holes in the CO2 cover that after a couple bounces, all will make it out into space. Net gain…. not much. Screen doors on submarines don’t keep the water out. CO2 is a screen door… too many holes in the coverage to do much benefit.

Brian H
February 28, 2011 7:49 pm

Brief note to Myrrh;
All incoming radiation that reaches the surface heats the Earth. It is absorbed by one form of matter or another, which causes kinetic agitation — i.e., heat. It can’t be re-radiated at those same wavelengths because that would require being as hot as the source, the Sun. It gets emitted at the wavelengths matching the temperature of the matter/material emitting. That’s in the IR band for the temps we experience.
In deep space, much material is much colder, and emits at even lower wavelengths, down in the radio bands. Other higher frequency radiation also comes in on those bands after being “red-shift” stretched by the relative recession of the sources from our POV. Such as the putative “Big Bang” cosmic background patterns.

Theo Goodwin
February 28, 2011 7:51 pm

bubbagyro writes:
“CO2 is generated on the earth’s surface. It becomes more dilute as it diffuses upward. The models, similar to Ira’s, assume it is a narrow band. This is not true. The very dilute CO2 and water even in the stratosphere absorb radiation. The higher that occurs, the more is lost to space.”
Please expand on this. My understanding is that the modelers assume that concentrations of CO2 are the same wherever they occur in the atmosphere – all the way up. In addition, they assume that the behavior of CO2 molecules regarding radiation is the same throughout the atmosphere. It has always seemed to me that these “uniformity” assumptions were just evidence of an unwillingness to do the necessary empirical research. In plain and simple terms, I would like someone to address the linked questions of “where are the CO2 concentrations and how does radiative behavior change depending on where they are?”

Brian H
February 28, 2011 7:53 pm

Correction/refinement of above: “All incoming radiation that reaches the surface and is not reflected …”

James Sexton
February 28, 2011 8:09 pm

bubbagyro says:
February 28, 2011 at 7:11 pm
Oh, no!
I did it again, misspelled my /unbolding. It was only meant for one word.
Sorry.
=======================================================
They are some really nice guys! They fixed it for you!

Dave Springer
February 28, 2011 8:12 pm

“I plan to do a subsequent posting that looks into the violet and blue boxes in the above graphic and provides insight into the process the photons and molecules go through.”
Please don’t go into quantum electrodynamics. The scales involved don’t warrant it and I guarantee you no good will result from it unless further confusion and unending arguments even between the PhD physicists here is your goal.

KevinK
February 28, 2011 8:19 pm

Oh, one other observation for Ira, by continuously mentioning Albert Einstein’s name in all of your posts you are in fact doing yourself a disservice. You may think that it increases your credibility and more people will automatically accept your arguments since you “drop” Al’s name, but it only works for a small portion of the audience.
I for one evaluate your posts based solely on their merit. Just because you make nice graphics in the “spirit of Albert Einstein” does not make me give your arguments any more weight. If my garbage collector makes a good argument I consider it with just as much logical analysis as I do yours.
Just an observation, you might want to go heavy on the LOGIC and light on the “Al Einstein agrees with me” thing.
Cheers, Kevin.

Dave Springer
February 28, 2011 8:20 pm

You know Ira, there’s a quantum explanation for why you squint your eyes in bright lights. There’s also no good reason to ever try to explain it in quantum terms when a macroscopic explanation is far simpler and completely adequate for any practical purpose. The same goes for the greenhouse effect. Quench that desire. Just say no.

Chad Woodburn
February 28, 2011 8:38 pm

When the up-going long-wave radiation gets reflected back to the earth, how long does it take for it to “bounce off” the earth and return to the level where it was previously reflected back to the earth? (Or does it not work that way?)
How long does it take for the long-wave radiation to completely dissipate during the night? (If it does not, how much of it is still there when “new” long-wave radiation joins it after sunrise?)
How long does it take after sunrise for the GHG in the upper atmosphere to again get saturated with long-wave radiation?
If the long-wave inventory returns to negligible levels by morning, what difference would that make to average global temperatures in contrast to the inventory staying relatively high (or static)?

D. J. Hawkins
February 28, 2011 8:53 pm

kbray in california says:
February 28, 2011 at 7:47 pm
…I realize this is not a perfect analogy. CO2 purports to reflect certain wavelengths back to the planet. I visualize CO2 in the atmosphere like a screen door on a submarine…. Some of the energy waves will get reflected back, but there are so many holes in the CO2 cover that after a couple bounces, all will make it out into space. Net gain…. not much. Screen doors on submarines don’t keep the water out. CO2 is a screen door… too many holes in the coverage to do much benefit.

This was sort of what I was alluding to regarding the behavior of CO2 in the atmosphere. Your black ball can’t be based on the proportion (molar volume) of CO2 in the atmosphere; it has to be proportional to the effect of the CO2 in the atmosphere. You say it’s a “couple bounces.” I say…does anyone know for sure? Or have a defensible WAG?

bubbagyro
February 28, 2011 9:08 pm

Theo Goodwin says:
February 28, 2011 at 7:51 pm
I did not want to elaborate, because it is an onion skin, that keeps revealing more layers of variables. More variables than explanatory equations. For example, CO2 is never free. When water vapor is present, depending upon humidity, it is associated reversibly into carbonic acid: CO2 + H2O ⇌ H2CO3. This is a highly radiation absorptive species, probably across most of the bands. The higher the humidity, the more the CO2 is associated. This will absorb incoming radiation at most UV, visible, and IR wavelengths.
Then there is quenching. (Thanks for mentioning, David). If a molecule is excited by a wavelength, then it can reradiate at higher wavelength (always higher, because lower energy—2nd Law). OR, it has another choice. Another species can “steal” the energy of the π to π* transition state, and excite itself (I’m getting excited). OR, it can do chemistry.
If a CO2 molecule is excited by IR, let’s say from below, then it can reradiate a higher wavelength IR (direction of that photon is up, down, or sideways, on average). OR, it can have the energy stolen (quenched) by SO2, or CFCs, or chloride, or water, or ozone, or carbon particulates, or dust, or…
The trouble with the models is that they do not test all of the available permutations of all the species present at all locations and levels of the atmosphere.
Hence, they simplify, and show us the absorption spectrum of pure CO2 in a vial under ideal conditions.
Then their is the horrendous problem of diffusion and diffusivity of gases.
Then we have the states of matter, especially water. Water associates in complex ways, forming structures in the low atmosphere. It is most dense when it is at 4°C, yet expands pronouncedly when it is cooled to 0*C.
Many variables, few equations. Chaos for models.

kuhnkat
February 28, 2011 9:18 pm

DccMartyn,
the ozone is broken down by the radiation it absorbs. I am told there is no energy radiated from this interaction.

kuhnkat
February 28, 2011 9:27 pm

Dave Springer,
You use a common graph of the Arctic. I was wondering why you would use a graph of the second dryest place on earth, the dryest being the Antarctic. These would seem to show a much larger absorption by CO2 when water vapor is the largest effect in most other areas on the surface especially since the poles have a lot less energy to radiate.

rbateman
February 28, 2011 9:27 pm

Dave Springer says:
February 28, 2011 at 7:36 pm
I strongly suspect that the GCR’s are a variable, and that variable is modulated by the level of Solar Activity.
To be very blunt, the level of incoming GCR’s would vary even if the Sun were to remain constant in activity.
You could have low GCR levels coupled with low Solar Activity or high GCR levels with high Solar Activity, and both cases would produce much the same result.

James Sexton
February 28, 2011 9:34 pm

” Whence arises this uniformity in all their outward shapes but from the counsel & contrivance of an Author? Whence is it that the eyes of all sorts of living creatures are transparent to the very bottom & the only transparent members in the body, having on the outside an hard transparent skin, & within transparent juyces with a crystalline Lens in the middle & a pupil before the Lens all of them so truly shaped & fitted for vision, that no Artist can mend them? Did blind chance know that there was light & what was its refraction & fit the eys of all creatures after the most curious manner to make use of it? These & such like considerations always have & ever will prevail with man kind to believe that there is a being who made all things & has all things in his power & who is therfore to be feared.” —- Isaac Newton…….(emphasis mine)

February 28, 2011 10:32 pm

A useful post and an important topic not often given an airing.
For an alternative view of the long wave effect have a look at:
http://www.climatedata.info/Forcing/Emissions/introduction.html
With regard to the question on variability of outgoing radiation have a look at:
http://www.climatedata.info/Forcing/Forcing/albedo.html

derspatz
February 28, 2011 10:46 pm

The Late Great John Daly was writing about this kinda stuff (and of “Fraunhofer bands”) over a decade ago in his excellent book “The Greenhouse Trap – why the Greenhouse Effect will not end Life on Earth” … of which I’ve had a copy of for nearly as long.
regarDS

HankHenry
February 28, 2011 11:01 pm

Dave Springer
Thanks for the thorough reply. It is helpful to me. Of course, I’m not completely satisfied with this answer about empirical measurements replacing theoretical ones.
I was thinking about Einstein’s (and others) investigations of Brownian motion as something to give me a lead into better understanding of the movement of heat through the atmosphere. I am guessing that heat radiating from the surface molecules of a solid also radiate in the same way within the solid. This talk of radiation conflicts with my understanding of heat conduction being vibrational. Although I suppose the two aren’t mutually exclusive; I’ve never thought of it that way.
From what I’ve read Big Bear observatory has data demonstrating that albedo is variable even on the scale of decades using a technique conceived of by DaVinci. … Fascinating.
http://www.sciencedaily.com/releases/2001/04/010418072342.htm
http://www.sciencedaily.com/releases/2004/05/040527233052.htm
http://www.sciencedaily.com/releases/2009/04/090407105156.htm
I am just a lay reader of science, and it is important to understand something about models to gauge whether the scientific consensus that I read about is real, or whether there is a large group of scientists that have fashioned their views and taken a stance because an important moral matter is at hand. Do you think it really possible that there is a large number of scientists that have delved into the working of these models and formed their judgments on climate change based on what they understand about the workings and the reliability of models.

izen
February 28, 2011 11:10 pm

Fred Souder says:
February 28, 2011 at 2:31 pm
“Ira,
Are there any experiments which detect the incoming re-emitted radiation from the atmosphere? Did a quick search and only came up with models. It seems like we should be able to detect the radiation coming back at us from the atmosphere if this model is valid.”
Try this –
http://www.gewex.org/bsrn.html
Baseline Surface Radiation Network (BSRN)
About BSRN
Because of the important role radiation plays in the climate system, the Baseline Surface Radiation Network (BSRN) was established to provide a worldwide network to continuously measure radiative fluxes at the Earth’s surface.
Or-
http://ams.confex.com/ams/Annual2006/techprogram/paper_100737.htm
Measurements of the Radiative Surface Forcing of Climate
W.F.J. Evans, North West Research Associates, Bellevue, WA; and E. Puckrin
The earth’s climate system is warmed by 35 C due to the emission of downward infrared radiation by greenhouse gases in the atmosphere (surface radiative forcing) or by the absorption of upward infrared radiation (radiative trapping). Increases in this emission/absorption are the driving force behind global warming.

kbray in california
February 28, 2011 11:31 pm

[[[ D. J. Hawkins says:
February 28, 2011 at 8:53 pm
… Your black ball can’t be based on the proportion (molar volume) of CO2 in the atmosphere; it has to be proportional to the effect of the CO2 in the atmosphere. You say it’s a “couple bounces.” I say…does anyone know for sure? Or have a defensible WAG? ]]]
This is not my field of expertise, however, I don’t like treating CO2 molecules like they are magic “heat” beans. Some of the effect attributed to them I regard as speculative or a current theory. I am skeptical about this influence. Every CO2 molecule takes up a measurable space or volume in the airmass. I treat it as a simple molecule and go from there. There are not enough of them floating around to do much in my opinion. Giving CO2 special powers or as you say “proportional to the effect of the CO2” is magical thinking in my book. I suggest that CO2 might bounce energy around but it eventually escapes into space. Heat has to leave Earth otherwise it would keep building up and we would eventually ignite in flames. Our current atmosphere, land, and sea seem to have an intrinsic control mechanism that swings between certain stable limits. I do not believe that CO2 is a zombie monster out to kill us. It is a minor player in “warming”. If we do accelerate a “warming” somehow, I imagine it will just start the reverse swing sooner than it would have happened because we hit the trigger limit faster than its “natural” oscillation . This is only an opinion based on my sum of life experiences so far. I am happy to learn more or be corrected if it can be proven accurate.

P. van der Meer
February 28, 2011 11:49 pm

Ira Glickstein says in his article above:
“The absorbed radiation heats the H2O and CO2 molecules and, at their higher energy states, they collide with the other molecules that make up the air, mostly nitrogen (N2), oxygen (O2), ozone (O3), and argon (A) and heat them by something like conduction. The molecules in the heated air emit radiation in random directions at all bands (~7μ, ~10μ, and ~15μ). The ~10μ photons pass, nearly unimpeded, in whatever direction they happen to be emitted “
No, they don’t because Kirchoff’s law of thermal radiation states that emissivity and absorptivity must be equal to each other. If the surface can emit unhindered in the 10μ band without absorption in the atmosphere than that means that absorptivity of the atmosphere is zero and therefore emissivity must also be zero. The conclusion of this is that the atmosphere cannot possibly emit in the 10μ band.
And using the argument further, the atmosphere can only loose heat by CO2 and water vapour emitting radiation in their respective bands.
The model as presented by Ira does not reflect reality!

Richard111
February 28, 2011 11:53 pm

May I suggest some consideration be given to the Maxell-Boltzmann kinetic energy distribution curves on which subject Tom Vonk made an excellent post here on WUWT a while back.
http://ibchem.com/IB/ibnotes/full/sta_htm/Maxwell_Boltzmann.htm
http://dwb.unl.edu/teacher/nsf/c09/c09links/www.kobold.demon.co.uk/kinetics/maxboltz.htm
To me these effects imply that most long wave radiation absorbed by GHGs in the atmosphere is thermalised and “back radiation” is not related to the MASS of the GHGs in the atmosphere. A simple example is compare average surface temperatures at or near the equator to the average surface temperatures in the desert regions north or south of the equator. True there is more cloud at the equator because of the higher humidity but why doesn’t the temperature rocket up when the sky is clear? I have lived for some years in Singapore and never experienced temperatures there that I experienced in the Namib desert. Yet which region has the most “greenhouse” gases?

March 1, 2011 12:01 am

Ira Glickstein, PhD said:
“The ~10μ photons generated by the heating of the air emerge from the top of the Atmosphere”
I am sorry, but for the sake of accuracy, CO2 in air does not have any states that interact with 10-13um band. Therefore, hot air cannot possibly generate any photons in that range. Therefore the following statement is also wrong, nothing gets “transferred” into 10-um band from “heated air”:
“The ~7μ and ~15μ generated by the heating of the air also emerge from the top or bottom of the Atmosphere, but there are fewer of them because they keep getting absorbed and re-emitted, each time with some transfered to the central ~10μ portion of the longwave band.”
As result, the entire explanation of greenhouse effect is wrong. The emission from ~7um and ~15um bands is smaller than at the surface because the overall TEMPERATURE of air is smaller at that height (of emission to space). The temperature gets lower with height because of purely mechanical property of convectively-stirred turbulent atmosphere in the field of gravity, when it HAS to form the vertical temperature gradient called “lapse rate”. No matter what kind of radiation gets diffused (and locally emitted-absorbed) through the air, this mechanics overrides (complements) the process and forms the steady (on average) gradient no matter what. The 10-13um photons just shine through without much interaction with air, all straight from the Earth surface.
In the animated picture the pink and dark blue areas should not have any 10um components.

March 1, 2011 12:48 am

“A real greenhouse primarily restricts heat escape by preventing convection while the “greenhouse effect” heats the Earth because “greenhouse gases” (GHG) absorb outgoing radiative energy and re-emit some of it back towards Earth.”
Has WUWT become a “lukewarmer” site and abandoned Climate Realism?
This is pure nonsense and I’m surprised that WUWT would print such rubbish. Infra Red Interacting Gasses (IRIGs) CANNOT heat the earths surface. To do so would mean the colder air is warming the hot ground and that goes against the laws of thermodynamics.
Clearly impossible! (See slaying the Sky Dragon ).
The “greenhouse effect” on earth actually does work much the same as an actual greenhouse. It is due to the relative slowness of convection that keeps the earth surface from instantly freezing at night.

izen
March 1, 2011 1:27 am

@-Ira Glickstein, PhD says:
February 28, 2011 at 10:44 pm
“However, since the Sun and the Earth act pretty much like “blackbody” emitters, with a wide range peaking at a characteristic wavelength based on temperature, I now think the Atmosphere is about the same.”
That assumption may not be warrented.
The atmosphere may not be a ‘blackbody’ radiator, given Kirchoff’s law the emissivity is equal to its absorptivity(?), so the emission spectrum of the atmosphere should mirror its absorption spectrum which as you have so ably described is VERY different from a ‘blackbody’.
The emissivity of the atmosphere is going to be prefferentialy concerntrated in the H2O and CO2 bands because these are several orders of magnitude ‘better’ at absorbing and emitting at these wavelengths than the N2 AND O2 are at any wavelength.

cal
March 1, 2011 1:28 am

Ira, a couple more comments.
The temperature of the sun is in fact an artifact of its radiance. The sun’s actual temperature ranges from several millions of degrees at its core to about 3 million degrees in the very diffuse corona above the “surface”. The photosphere or “surface” is sandwiched between these extremes and behaves as if it were a black body at 5840K. This can be determined approximately by its total power output and peak wavelength and accurately by its absorption lines which are temperature dependent. This does not contradict anything you said but may reassure those who look at the very low temperature and think “how can that be true?”.
Secondly I have re-read your paper and realised that there is something I do not believe is correct. It relates to the point I made in my earlier comment to George E Smith and was restated rather more strongly by Tim Folkerts when he said “I must disagree with the comments to the effect that N2 & O2 radiate (or absorb) any important amount of IR”.
You talk about the “7 and 15 micron photons” being absorbed and then some of this energy being passed to other gas molecules and being re-radiated as “10 micron photons” with some of these being lost to space. This implies that there are gas molecules around that can radiate at this wavelength. However if there were then there would not be an atmospheric window. The very reason that this window exists is that there is no absorption and therefore no radiation at these wavelengths.
Incidentally, I may be wrong but, I get the impression that some posters believe that there are two types of radiation: radiation at specific wavelengths and blackbody radiation. In reality black bodies are radiating and absorbing at specific wavelengths it is just that they do so with 100% efficiency at all wavelengths. A grey body also absorbs and radiates with the same efficiency at all wavelengths but does so with less than 100% efficiency.
The earth is close to being a grey body for the infrared part of the spectrum where it emits but it is not a grey body in the visible region. That is why the sea is blue! The atmosphere is nothing like a black or grey body and can never behave like one. As I explained in my previous post the combination of the earth’s surface and the atomosphere results in the grey body emission of the surface being modified by the absorption bands of the IR absorbing gases like H2O and CO2 to give dips in the spectrum particularly around 7 micron and 15 microns when viewed by satellites.

Dave Wendt
March 1, 2011 2:14 am

Why is it that everyone who attempts to create a cartoon or animation to illustrate how the “greenhouse effect” warms the planet, they always feature a big old Sun beating down. No matter which of the theories about the operation of the various component gases that comprise the atmosphere you chose to embrace, you have to recognize that when the Sun is shining on the Earth the main function of the atmosphere is to make the surface of the planet much cooler than it would be without it. If the Earth were just a larger version of the Moon, without an atmosphere, its daytime temp would be close to that of the Moon. The only difference being provided by the differing lengths of the diurnal cycle. If you compare the max, min, and mean temps for the Earth and the Moon it seems to me that, whatever the atmosphere is doing to make the Earth warmer than its theoretical blackbody temp, its doing most of it at night by increasing the min temps. I keep waiting for someone to do one of these neat climate schematics that features a big full Moon and radiative conditions that prevail when the Sun isn’t shining. It seems to me that that is where the “greenhouse effect” dwells, though I still believe that the “flywheel effect” is a more accurately descriptive analogy of what the atmosphere does for the planet.

Myrrh
March 1, 2011 2:45 am

Brian H says:
February 28, 2011 at 7:49 pm
Brief note to Myrrh;
All incoming radiation that reaches the surface heats the Earth. It is absorbed by one form of matter or another, which causes kinetic agitation – i.e., heat. It can’t be re-radiated at those same wavelengths because that would require being as hot as the source, the Sun. It gets emitted at the wavelengths matching the temperature of the matter/material emitting. That’s in the IR band for the temps we experience.

Brian, I have a real problem with that explanation in the graphic that it’s only Visible and near shortwave that heat the Earth kinetically, a.k.a. “Solar”. Your “all incoming radiation reaches the surface of the earth” isn’t addressing that, because that’s what I’m saying is happening… Because all radiation includes Thermal IR which isn’t in the chart.
Ira says that Visible is the largest part of the Sun’s spectrum, wrong, it’s actually the smallest, and compared with the others, very very small. Light is not hot, it is Reflective not Absorptive, and your use of “absorbed by matter of one form of the other” is misleading. The radiation that penetrates to heat the Earth is Thermal IR. And that is not in the Chart.
So, not only is downwelling Thermal IR taken out of the equation, it is replaced by the very strange notion that Visible light and its two other cool neighbours, by themselves heat the Earth, called “Solar”. I can sit infront of the TV all day in a cold room, it won’t heat me.
What I want here is conclusive proof that it this narrow band of non-thermal light energy which is the sole cause of the ground and rocks and me heating up from the Sun. That’s basic premise to the AGW Energy Balance claim as shown in the Charts.
And no, it does not require the source to be as hot as the sun to radiate out Thermal IR, the electric plate on your stove doesn’t have to be even hot enough to produce red light for you to feel the IR it is radiating, but that doesn’t mean that the Sun isn’t radiating our Thermal IR! That’s reaching the Earth at the same time as Solar. And is better going through water vapour, fog and mist, than Visible Light.
The Earth being heated by kinetic energy alone by Solar without any mention of of the Absorptive energies from the Sun of Thermal IR is nonsense, which is the AGW claim. I’m asking for proof it isn’t nonsense.

March 1, 2011 2:55 am

The ~10µ photons generated by the heating of the air emerge from the top of the Atmosphere and their energy is lost to Space,
The ~7µ and ~15µ generated by the heating of the air also emerge from the top or bottom of the Atmosphere, but there are fewer of them because they keep getting absorbed and re-emitted, each time with some transferred to the central ~10µ portion of the longwave band.
Complete nonsense. The reason that the 10µ photons from the surface are able to reach space is because the atmosphere does not absorb them. For exactly the same reason, the atmosphere also does not emit radiation at the wavelength.
Jim D does point out one exception, clouds.
I also agree with Jim D that greenhouse gases have a net cooling effect. When convection from the surface is included in the analysis, it is obvious that increasing the amount of CO2 cools the atmosphere more than it adds heat.

March 1, 2011 2:59 am

In addition to the problems in the main post, there are numerous errors in the comments.
George E. Smith says:
The AGW types, like the frequency scale, because that puts the CO2 frequencies near the peak of the curve
Actually, the frequency (wavenumber) scale gives a more intuitive plot when discussing the amount of energy. Note, the wikipedia graph uses log of wavelength which completely distorts the plot.
the actual amplitude of the thermal spectrum should be about 80 times smaller than it is.
Well, that depends on the x-axis selection. When frequency (wavenumber) is selected, it is the solar spectra that is about 28 times too high. When wavelength is selected, the 300K curve should be about 10 times smaller.
The only function of the GHG molecules is to heat the atmospheric gases; along with all the other mechanisms that are heating it. After that, the GHG molecules serve no function in the climate process whatsoever.
True, they do heat the atmosphere .. however, they also cool it. In fact, greenhouse gases provide the only method to cool the atmosphere. Note that some of the energy they release returns to the surface producing the greenhouse effect.

March 1, 2011 3:02 am

wayne says:
where in the heck did 5525K for the sun’s temperature come from?
Scientists have measured the spectra of the Sun and temperatures near 5,777 K produce a similar blackbody spectrum. However, the references use many different values. For instance, the wikipedia plot above references ~5500 K.
There are several very good reasons why the references don’t agree
* The real spectra is not very close to any blackbody spectra (slightly different shape)
* The measurement devices do not agree
* The radiation temperature of the center of the solar disk is higher than the apparent temperature near the edge
* The temperature of the outer corona is more than 1,000 hotter than the “surface”
* The Sun does not have a surface
* The distance between the Earth and Sun varies (the orbit is an ellipse), and different references handle this differently
However, what is known fairly well is the number of watts at the top of the atmosphere (TOA).

March 1, 2011 3:04 am

John of Kent says:
Has WUWT become a “lukewarmer” site and abandoned Climate Realism?
This is pure nonsense and I’m surprised that WUWT would print such rubbish. Infra Red Interacting Gasses (IRIGs) CANNOT heat the earths surface. To do so would mean the colder air is warming the hot ground and that goes against the laws of thermodynamics.>>>
Oh my.
There’s so many things wrong with those few sentences that it would take paragraphs to correct them all. I sometimes wonder why it is that when science is well explained on this site, by highly technical people, who then engage in well informed debate and discussion with other highly technical people, the bulk of whom are skeptics or mild luke warmers at best, there is always some troll jumping in, spouting rage and ridicule, and denouncing the explanation as fraudulent? And why does the criticism almost always include the exact same two statements?
1. Cold things can’t heat up warm things.
2. That breaks the laws of thermodynamics.
Is there some secret troll society somewhere, a cabal of warmists perhaps, determined to mess up every serious discussion of greenhouse effect by shouting those two statements? Are they on a web site someplace worded a dozen different ways so that volunteers can just copy and paste to distract everyone else? Or maybe it is completely automated?
OK Kent, cold things can’t heat up warm things. Igloos freeze everything inside them to death, that’s why the Inuit are extinct. The laws of thermodynamics don’t allow for net energy transfer. That’s why if you take two very hot things at the exact same temperature and put them side by side, there’s no energy transferring between them so you won’t burn yourself if you stick your hand between them, the laws of thermodynamics say you’ll be just fine. Kent…KENT KKKKEEEENNNNTTTT don’t actually do it!!! Phew. I thought you were going to try it. Would have felt bad about that.
There’s dozens of threads and hundreds of comments on this site from very well informed skeptics (amongst others) explaining the facts. You would do well to read many of them before popping off with comments that can be falsified by building an igloo.

March 1, 2011 3:07 am

Several people have said that a cold sky can not heat a warm surface. The truth is that it can. What they miss is that the “cold sky” is much warmer than the colder microwave background. So, while it may be true that a cold body won’t heat a warmer one, it will slow down the heat loss if the cold body wasn’t there.
In addition, at night the air in the lower 1,000 meters is warmer than the surface.

wayne Job
March 1, 2011 3:57 am

When it comes to our little blue planet, all this hypothetical analysis of incoming and outgoing radiation in various wave lengths, and how much is reflected back and how much escapes is neatly summed up by by Humphrey Bogarde, It does not amount to a hill of beans. The amount of heat our world receives and its reaction to it gives us our chaotic but wonderfully variable climate. I find it some what incongruous that people find small changes in things like CO2 can cause warming and cooling besides drought and floods, not to mention no snow or massive snow. The entire argument is total nonsense. It is and always will be the sun and solar mechanics that control climate, anything else will be but a bit player and not relevant to our climate.
We have a heat pump Earth that uses water and water vapour as a control mechanism every thing else is irrelevant. It is time to ask our great sun god Sol to awaken for the energy balance is tipping to the cool side. As our moderating fluid in the oceans cool as it would seem is happening no amount of nit picking as to what IR radiation is going up or down is going to be diddlysquat as far as our well being is concerned.
The world has suffered a concerted propaganda effort by the by so called experts to brain wash the west into believing that we are evil polluting monsters, AGW never was about global warming, it was about control power and wealth distribution.
Discussing radiative imbalances is a digression to keep those with cognitive thought busy whilst evil is committed.
Those here on this site show huge education and intelligence but this subject has nothing to do with global warming the IPCC is totally political with no real science involved. Confound the science of global warming all you like but the politics and the lies will keep overwhelming you in the compliant MSM.
It is time for a different tack for the science is becoming irrelevant as the brainwashing of the young is total in the schooling system. I have no answer but many on this site are far more intelligent than I and may have an antedote to this modern day grab for control. Cheers Wayne

March 1, 2011 4:00 am

Ira,
I think the explanation of the atmospheric window that you posted is reasonably sound, but I think the discussion has wandered off the most important aspect of it. Yes, sensitivity and greenhouse effect and what molecules radiate at what frequencies are all parts of the discussion, and necessary for understanding the climate as a whole. But in relation to the atmospheric window, I think these are relatively minor. The atmospheric window has an effect on earth temperature that I think is far more significant than how it interacts with the greenhouse effect. The important aspect of the atmospheric window is how it interacts with ALL upward bound radiance regardless of source.
Consider the black curve in your diagram, which represents the distribution of LW radiation emitted by a surface at 210 degrees Kelvin, or -63 C. The peak of the black curve is BEYOND the atmospheric window. Guestimating from the drawing, a surface at -63 C would be only emitting about 30% of its radiance in a spectrum that can escape freely to space. The rest is impeded by absorption and re-emission. But the centre curve, at 260 Kelvin, or -13 C, is smack dab in the middle of the sweet spot. For argument’s sake, let’s call that 50% going straight out the window. Then look at that pink line…uh oh….310 K… 27 C….. the percentage going out to space is dropping back down, the hotter it gets, the less surface radiance is in the escape window…25%? Less? Can you hear the tipping point argument sneaking up on you?
Of course the tipping point argument is ludicrous. Falsified by no other means than the conditions that supposedly would create it have existed multiple times in the geological record, yet no tipping point occured. The question is not if the tipping point is possible, the question is why ISN’T is possible, and the atmospheric window is a big part of that. As another commenter alluded to earluer, the geological record shows that the earth varies between certain upper and lower temperature bounds, and the atmospheric window has much to do with that also.
The lower end is in my mind the easier of the two to understand, and also easier to demonstrate. Once the earth surface cools below a certain temperature, it loses heat via radiance that is increasingly outside of the atmospheric window. In brief, the colder it get in that temperature range, the more effective the atmosphere is as insulation. You can see this easily in the temperature record. Anyone who lives in a cold climate, say Winnipeg, at 50 degree N latitude will talk with a certain amount of pride about surviving -40 C. Thompson, well north of that they will talk about…. -40 C. Keep going north. In fact, let’s go right to the arctic circle and take a look at the temperature record from DMI:
http://ocean.dmi.dk/arctic/meant80n.uk.php
Pick any year you want. Winnipeg in the depths of winter gets a few hours of sunshine every day. The arctic circle gets none for WEEKS. Yet look at the lows. Hardly ever gets past -40. The window is closed to the heat being radiated at that temperature.
What of the high end? Why no tipping point? That’s more complicated of course. For starters, you can actually see that in fact the atmospheric window does start to close as earth surface warms up. Here’s a snapshot of ERBE:
http://knowledgedrift.files.wordpress.com/2010/01/erbe-zonal-1986.gif
The tropics are for the most part slightly positive in terms of net radiation, they absorb more heat than the radiate (which is why its hot there!) and they would in fact ignite if they couldn’t get rid of that heat via convection and other processes. But you can see that the atmospheric window is pretty much closed to the wavelengths being emitted by the warm tropics. Then take a look at the arctic zones. Holy cow grandma, them windas is wide open, look at all them photon torpedos justa leakin’ out ta space, no wonder its so darn cold here, we gots ta build us an igloo right fast or we gonna freeze solid….what’s that grandma? igloos won’t work because they violate the laws of thermodynamics and cold stuff can’t keep warm stuff warm? Ya been datin’ that troll Kent agin’?
So part of the answer (sorry Kent, had to take that shot) is that convection at the tropics raises warm air upward where it eventually spills toward the poles. As it cools, it is radiating increasingly into the atmospheric window. Cool air from the poles works its way to the equator to replace the rising hot air picking up heat as it goes. For the most part it starts out cold, below the atmospheric window, and warms, radiating to space more efficiently until it gets “too” warm. But the hotter the tropics get, the faster the cycle goes. Check out the GISS or HadCrut broken down by latitude and you’ll find the tropics are VERY stable, even though they are the net retainers of heat for the planet. Any variation in solar or anything else gets pushed to the temperate and arctic zones for mandatory expulsion to space.
Of course there are other factors too. Those curves represent the RELATIVE distribution of wavelength radiated, they do NOT represent ABOSLUTE magnitude. Since the amount of energy the surface radiates is proportional to the temperature in degrees K raised to the power of FOUR (squared squared!) there’s an awfull lot more photon torpedoes pointed at space from the +27 C tropics than there are at the -63 C poles. So part of the reason for -40 being a sort of bottom end is that the atmospheric window is nearly closed AND there’s less photons being fired upward besides.
However, at the top end, even at 27 C, there’s still a healthy percentage of that curve radiating within the window, and the total being radiated is MUCH bigger. Grab a calculator and do 210^4 then do 310^4. Even if only 25% of the torpedoes at 310 get fired off within the range of the window, that’s still more than 100% of the torpedos at 210. Does that mean a tipping point is impossible? YES! You’d have to heat the planet to the point where even the POLES are more than 300 degrees K warmer than the top end of that window. Do the net radiation calculation for THAT temperature. OK, NOW we have a violation of the laws of thermodynamics.
Grandma… GRANDMA… ya can come out now, yu and Kent there done melted that igloo.

richard verney
March 1, 2011 4:05 am

Dave Springer comments at February 28, 2011 at 7:36 pm are well worth a read, especially the point he makes aboud clouds (a point I made in my earlier post).
Whilst CGR may be an explanation for changes in clouds/cloud seeding/ cloud patterns, there may be other explanations for these changes. Indeed, in a chaotic system (such as weather/our atmosphere) one would expect there to be changes in clouds and their patterns. Further, given that we are looking at such a small time scale (circa 100 years) it would not be surprising if during such a short period there was a tendancy (ie., a trend) for less cloudiness and hence a slight upward trend in temperature. This might be nothing more than natural variation on the time scales that we are looking at.
Personally, I consider that an explanation along these lines is a more plausible explanation (by many orders of magnitude) over that of CO2 being responsible for the warming. Given that current computer models do such a poor job with clouds, we cannot rule this out.

March 1, 2011 4:16 am

I think etudiant has an interesting point concerning the jetstream (300mb level) and the reduction in its relative humidity. Following the reasoning of Steven Wilde a link may be considered concerning the temperature gradients at these heights in the atmosphere and the position (or changes therein) of the high speed vortices around the world driving the weather patterns and ultimately the climate.

Bill Illis
March 1, 2011 5:14 am

Tim Folkerts says:
February 28, 2011 at 7:23 pm
I must disagree with the comments to the effect that N2 & O2 radiate (or absorb) any important amount of IR.
Look at a somewhat similar and more familiar idea – visible light emitted by a Hydrogen atom (the Bohr model covered in freshman chem & physics around the world). It is easy to observe that H only emits very specific energies of light which are “easily” predicted by the quantum mechanics of the orbiting electrons and the allowed transitions between energy levels of those orbits.
————————————
But the Sun emits mostly like a blackbody.
It is not being emitted in the Hydrogen frequencies only, it is emitting across the entire spectrum close to what the blackbody curve predicts. If anything the Hydrogen spectra are suppressed (much like the CO2 spectra is suppressed on Earth) and it emits a little more energy in the non-specific-absorption frequencies (more in the visible).
The absorption and emission spectra bear special attention, but not all the attention.
http://commons.wikimedia.org/wiki/File:EffectiveTemperature_300dpi_e.png
http://en.wikivisual.com/index.php/Image:Solar_irradiance_spectrum_1992.gif

Phil.
March 1, 2011 5:39 am

Ira Glickstein, PhD says:
February 28, 2011 at 10:02 pm
Kevin says:
February 28, 2011 at 2:52 pm
“From the looks of that first chart, ~100% of 7μ and 15μ radiation gets absorbed by the atmosphere on the way back to space, mainly by H20 and CO2. Maybe a tiny trickle bounces its way from molecule to molecule and makes it to space.”
If that’s so, then doubling or even tripling the values of H2O in our atmosphere should have no effect on absorbtion. You can’t absorb more than 100% of the radiation, right?
As you know, the “temperature” of a gas, such as the Atmosphere, is an abstraction of the average speed of the N2, O2, O3, H2O, CO2 and other molecules that make up that gas. When GHGs absorb a photon, they do not hold onto it forever. Rather, in their energized state, they may re-emit it or they may move faster and, by colliding with non-GHGs (such as N2) they will raise the temperature of the gas. Any mass, including a mass of gas, that has a temperature above absolute zero, will emit longwave radiation in random directions and at a variety of wavelengths, peaking at the wavelength corrresponding to the temperature of that gas, as indicated in the first graphic.

No, gases such as N2, O2 and Ar possess no dipole and are unable to emit in the IR. Gases do not emit as black bodies, they can only emit in certain wavelength bands which correspond to transitions between certain rotational/vibrational states. This is well established physical chemistry.

Ed Zuiderwijk
March 1, 2011 5:43 am

Unfortunately the text in the figure is incorrect.
It says: Downgoing solar radiation 70-75% transmitted. The part not transmitted (but reflected) is not downgoing anymore. This may seem pedantic (it probably is) but it informs the howler at the right: Upgoing thermal radiation 15-30% transmitted. This has to be: All, that is 100%, of the upgoing thermal radiation is transmitted (else it would not be upgoing anymore). The atmosphere is in long-term equilibrium which means that all thermally emitted radiation is in balance with the loss at the top of the atmospher to space. The semantic mistake is an indication that the maker of the figure confused the outgoing flux with the local source function.

Dave Springer
March 1, 2011 5:43 am

Chad Woodburn says:
February 28, 2011 at 8:38 pm
“When the up-going long-wave radiation gets reflected back to the earth, how long does it take for it to “bounce off” the earth and return to the level where it was previously reflected back to the earth? (Or does it not work that way?)”
Maybe instantly maybe 10,000 years. You can’t track energy by naming each photon and following them like airplanes on a radar display.
The ocean, like all things with a temperature above absolute zero, is constantly radiating energy out to the environment and absorbing energy from the environment at the same time. When an object and its environment are at different temperatures there is a net flow of energy from warmer to colder. The larger the difference the greater the net flow rate. So say the ocean at night is radiating 400 watts per square meter upward but greenhouse gases absorb 100 watts and half of that is radiated downward towards the ocean. So you have the ocean radiating 400w and absorbing 50w at the same time for a net flow of 350w out of the ocean. Now say we have a doubling of greenhouse gases such that they absorb 200w and radiate half of that downward. Now the ocean is radiating 400w and absorbing 100w for a net flow of 300w out of the ocean.
What this results in is a lower rate of cooling for the ocean. Like coffee in an insulated versus an uninsulated cup.
The net result of all this is that when the sun warms the ocean during the day greenhouse gases reduce the rate at which that energy can escape. So the ocean gets warmer than it would have absent the greenhouse gases. The warmer ocean radiates heat faster than a cooler ocean due to the larger temperature differential between the cold of outer space and the warm ocean surface. Thus a new equilibrium point is established where energy received during the day is lost at night. In the long haul all energy absorbed by the ocean is radiated back out into space. However there are many other dynamic things happening that keep changing the daily energy flow so that equilibrium becomes a moving target that can be approached but never hit. Some days are cloudy, some are not, so some days the ocean receives more energy and some days less. Evaporation, convection, ocean and wind currents move energy around mechanically from one place to another. But the bottom line remains that greenhouse gases slow down the rate of energy loss to space which causes a higher surface equilibrium temperature the system will target.

Tim Folkerts
March 1, 2011 5:55 am

Myrrh says: March 1, 2011 at 2:45 am
“Ira says that Visible is the largest part of the Sun’s spectrum, wrong, it’s actually the smallest, and compared with the others, very very small. Light is not hot, it is Reflective not Absorptive, and your use of “absorbed by matter of one form of the other” is misleading. The radiation that penetrates to heat the Earth is Thermal IR. And that is not in the Chart. ”
The issue here is the “size of the energy”, not the wavelength. There is a handy table at http://en.wikipedia.org/wiki/Planck%27s_law that shows the energy distribution of sunlight (above the atmosphere).
* A little over 10% of the ENERGY is in ultraviolet photons or shorter wavelengths.
* Close to 40% of the ENERGY is visible light photons
* Over 40% is “near IR” (from 0.7 – 3 um). (So Ira’s claim that visible is the biggest is not quite right, but it is not far off. On the other hand, the atmosphere is still mostly transparent to these wavelengths, so his arguments still hold).
* Only a few % is above 3 um (“thermal IR”) so it cannot possibly be the main source for heating the earth.

1DandyTroll
March 1, 2011 5:57 am

Greenhouses primary design is not to trap heat, but to control the environment, which includes to control the in house atmosphere which, of course, constitutes of gases.
So what you have in a greenhouse is a triple layer between the plants and the god ol’ Sol. You got the outside atmosphere (that apparently is working as a greenhouse effect), the glass (which apparently the outside atmosphere is functioning as), and the denser inside atmosphere (which apparently the outside atmosphere’s affect is the warming effect of.)
And greenhouses do not retain the heat very well, no insulation to keep the heat inside really and the much denser atmosphere does a really poor job of trapping the heat since the heat “escapes” so easily.
A greenhouse is in effect trying to mimic earth’s “summer effect” in a controlled manner. However, other ‘an summer days you usually have to add heat by other means since the heat “evaporates” so quickly to the outside, even with the inside having the denser atmosphere.
So I still claim that using the “greenhouse effect” as defined as something that gets warmer is just silly. Although if more people sported their greenhouses all through winter the power and gas companies would be ecstatic. :p

March 1, 2011 6:01 am

Ira –
I have grappled with the ‘basic physics’ for some time – having concluded from studying the flux data (courtesy of NASA), that CO2 can be accounting for at most 20% of the observed warming between 1980-2010. The main driver is very clearly percentage changes in cloud cover – I deal with this at length in my book ‘Chill: a reassessment of global warming theory’ – which calls for a re-analysis of the models. Obviously, if I am right, then there is something seriosuly wrong with the ‘basic physics’.
But I think you could be focussing your energy on an area of far greater importance than the emission spectra. It took me a long time to realise that the Radiative Forcing (RF) that is at the heart of the model calculations is centred on a notional point toward the top of the troposphere…defined by the temperature at which the earth will reradiate the balancing energy – which is -19 C and about 10km up. This is the point of notional equilibrium – a necessary condition for model initiation (it is very difficult to build in long term cycles and the reality of non-equilibrium when the causes of those cycles, as well as their amplitude and frequency are so poorly known).
So – the model calculations show that an RF of say 1.6 watts/square metre for current carbon dioxide levels will thus radiate downwards – this is a ‘forcing’ because it has moved the system from its pre-AGW (and fictitious) equlilibrium state.
This value , and the value for ‘doubling’ CO2 – at about 4 watts/square metre, is quoted everywhere you look – but just try to find the science of RF calculations to back it up!!! It took me a long time to find references in IPCC – I had to go back to 1990. Their special publication on RF is very unhelpful (and hard to find). I still found no academic scientific references. Eventually I realised that the IPCC reference to ‘offline computer codes’ meant the MODTRANS formulae which are produced by the USAF and can be accessed for $300! There may be others, but this unit seems to have the monopoly. I have no idea if there are error margins – but they do all the ‘basic physics’ calculating the heat transfers and photons and all that jazz at any altitude…and this model will allow you to input changes in greenhouse gases.
It is clear the MODTRANS RF model is LOG…..as many have posted on WUWT.
There may be nothing wrong with this level of the basic science – But references to this log relationship are VERY sparce in the literature. One colleague of mine persistently asked – ‘how can you say there is a log relationship between concentration of CO2 and its RF, when everything I see in the literature refers to a linear one?’ Eventually, I found him a point in IPCC where the (ln) equation was stated (but not referenced to an academic paper).
But then the Rf must be translated to a surface temperature – and that is far from basic physics.
I believe the first equations relating RF to temperature at the surface were courtesy of James Hansen – but I may not have the whole story. It is in THIS relationship that assumptions of linearity come in.
THUS….modtans calculates the RF at 10 km…..and say for a doubling we have an excess of 4 watts/sq metre of downwelling IR radiation.
Warmist science then has to translate this value into Temperature at the surface – and compare this to the observed T, and arrive at an equation T at surface = X (RF) where X is the factor that translates RF to T on a degrees C per watt basis. Remember, the RF has a log relation to concentration and Modtrans already assumed this, so the RF does not increase linearly with concentration. In calculating the RF we have to assume – in the absence of any critical scientific review of the privately produced modtrans model – that the asymptotic point has been calculated correctly. Actually, by the time you approach 200ppmv for CO2, you have already reached the break point in the curve, beyond which additional CO2 has much less impact on the RF – and this is close to the glacial value – suggesting that CO2 changes do not drive the glacial cycles (CO2 changes are supposed to amplify T rise during deglaciation, but there is scant evidence for this and the assumption that it did also underlay the IPCC belief – and a great many references in academic papers give a T degrees C per ppmv CO2 without stating over which range of concentrations this is meant to apply.
So – this X-factor must take account of everything that goes on beneath the calculated RF at 10km…..all the varying cloud and aerosol and water vapour. Values seem to vary between 0.4 and 0.8. This is the assumed ‘linear’ relationship that is always mentioned, whereas the original log relationship gets buried.
I suspect that given the paucity of knowledge in relation to clouds and aerosols (not to mention cycles)…the original X factors for the equation ranged through values that at the lower end produced no scary warming scenarios for the future doubling (ie at or lower than 1.5 C) to those that were very scary at 3-4.5 C – or even 6 C if you add strong feedbacks from melting ice, permafrost and emissions of methane. Hansen (and others?) was faced with such a range and chose the high ones – perhaps out of a genuine sense of precaution.
We should now be able to ascribe a real figure to the X-factor. If we can trust the RF calculation in the absence of effective peer-review – and using the observed global rise in T (criticism of urban heat islands and dodgy grid homogenising algorithms not-withstanding), then 0.7 = X (RF), where the RF for CO2 is…..? Do we take the final cumulative figure at the end of the observation period at 1.6? Or the increase since the beginning of the observation period? Taking the former – the RF given by IPCC for the CO2 is 1.6 watts (this is also the more approximate net forcing when all other GHG, cloud and aerosol factors are taken into account).
Using these values, the X-factor would be 0.43 with the proviso that it is determined over a century and that the system is at equilibrium (Warmists like to have it both ways here, ie that it was at equlibrium to start with, but not at the end, where there is ‘warming in the pipeline’ due to absorption and release of heat by the oceans). If we apply this value to the future predicted total net RF in 2050 of 3.7 watts/sq metre due to the mix of GHGs, then the resultant surface T is 1.59 C – and not at all a scary climate story.
Thus, observations tend to support a low factor X. Even this assumes that ALL the change in T from 1900 to 2010 was caused by the net downward flux or RF – the forcing, and there was no variation in any of the factors that contribute to that X factor such as clouds and aerosols, or warming and cooling cycles in the ocean heat reservoir – which is unlikely. The defending argument is that any such variables will be compensated for over the time period.
It is this X factor that needs attention – where is the peer-reviewed science? I assume it IS there, just not so readily available to the non-specialist scientific reviewer.
And actually, my final conclusion is that there is nothing actually ‘wrong’ with the basic science – it already includes these lower factors and a low prediction for doubling in 2050, but there is an assumption that this low prediction is very unlikely. This is not a problem with the basic science, rather a lack of awareness and bias on the part of the reviewers at IPCC and just about every academic institution that has supported their faulty analysis.
By the way – the IPCC Summary for Policy Makers has a graphic that has on the left side concentration of CO2 and on the right, the RF in wats/square metre – the right hand axis is shown as linear. This may account for the difficulty the IPCC has in accepting that future increases in CO2 will have very small impacts – they believe that graphic. The relationship is not of course linear, but logarithmic.

Bryan
March 1, 2011 6:08 am

Robert Clemenzi says:
………”Several people have said that a cold sky can not heat a warm surface. The truth is that it can.”……
A warmer surface will radiate more of every wavelength than it absorbs from the colder surface.
How then can we say the colder surface “heats” the warmer surface?
Heat means to “increase the temperature of “.
In fact it is more correct to say that the colder surface slows the rate of heat loss from the warmer surface.
In other words it insulates the warmer surface to some extent.
The igloo example will insulate the person inside to some extent.

March 1, 2011 6:19 am

Tim Folkerts says:
February 28, 2011 at 7:23 pm
“However, it is an observed fact (supported by theory) that monatomic gases (like argon) or symmetric diatomic gases (like N2 and O2) do not have vibration modes or rotation modes that would allow them to absorb (or emit) IR photons.
… IR is not absorbed or emitted by N2 & O2.”

A hot body that won’t radiate infrared?? That’s gotta be the best-kept secret in physics, if it’s true.

Alan McIntire
March 1, 2011 6:40 am

In reply to Katherine and to Phil’s dad. When the Earth’s temperature increases
from 1 to 1 + p, the total radiation increases by a factor of (1 + p) ^4,
Outgoing radiation increase at all wavelengths, but the PERCENTAGE increase at
short wavelengths, which are not affected by CO2, increases at a much larger rate.
So if CO2 results in 40 watts/500 total watts, with a 1% increase in the total to
505 watts, CO2 will absorb less than 40.4 watts. There’s a negative feedback due to that 4th power increase in radiation with respect to temperature, as you discovered, there’s also a negative feedback with respect to CO2 due to a larger percentage of increased outgoing radiation in wavelengths not affected by CO2.

izen
March 1, 2011 6:45 am

@-Myrrh says:
March 1, 2011 at 2:45 am
“Ira says that Visible is the largest part of the Sun’s spectrum, wrong, it’s actually the smallest, and compared with the others, very very small. Light is not hot, it is Reflective not Absorptive, and your use of “absorbed by matter of one form of the other” is misleading.”
The vast majority of the energy direct from the Sun that heats the Earth is in the visible spectrum, NOT the IR. If you doubt that visible light can heat things consider the car on a sunny day. The glass of the windows blocks IR but lets through visible light that is absorbed by the (usually) dark plastic/leather interior. The hot steering wheel and seat are warmed by the visible light not any IR.
You are correct of course that the surface is ALSO heated by the 7um and 15um IR emissions from the H2O and CO2 in the atmosphere that has been warmed by the IR emissions from the surface….

mkelly
March 1, 2011 6:52 am

cal says:
February 28, 2011 at 4:58 pm
“As I read it you seem to imply that the greenhouse molecules pass all their energy to the O2 and N2 molecules which then radiate into space. However they can’t since there is a law which says that a bad absorber cannot be a good radiator.
The rule is that you cannot have a net energy transfer in this direction but there is always energy being radiated from any body above absolute zero.”
OK which is it. N2 and O2 “can’t since there is a law” or “there is always energy being radiated from any body above absolute zero.”
You can’t have it both ways.

Vince Causey
March 1, 2011 6:52 am

Ira,
usefull schematics. However, some posters have pointed out that, according to Kirchoff’s law, if the atmosphere cannot absorb at 10 micro thingies, it can’t emit at that wavelength either, and therefore by implication, cannot this wavelength cannot appear as the result of being warmed by other wavelengths. I don’t pretend to know anything about Kirchoff’s laws, but if they are correct, this does present an issue with your model. Care to comment?

Vince Causey
March 1, 2011 7:04 am

John of Kent,
“To do so would mean the colder air is warming the hot ground and that goes against the laws of thermodynamics.”
Wow. Against the laws of thermodynamics. Which laws of thermodyamics did you have in mind? First law says that energy can be changed from one form to another but cannot be destroyed. That can’t be it then. What about the second law? Perhaps that’s what you meant. Let’s see. Here’s a quote about that from Wiki:
“The second law of thermodynamics is an expression of the tendency that over time, differences in temperature, pressure, and chemical potential equilibrate in an isolated physical system. From the state of thermodynamic equilibrium, the law deduced the principle of the increase of entropy and explains the phenomenon of irreversibility in nature. The second law declares the impossibility of machines that generate usable energy from the abundant internal energy of nature by processes called perpetual motion of the second kind.”
Talks about a tendency of temperatures to equilibriate and the impossibility of perpetual motion machines. Ok, if the colder air is supposed to be radiating towards the warmer ground, is that against the second law of thermodynamic?
Not necessarily. As long as the warmer ground is radiating more back towards the cold air than the cold air is radiating towards the warmer ground, their temperatures would equilibriate (if the ground wasn’t being continually warmed by the sun). Does this mechanism constitute a perpetual motion machine? No, because again, their temperatures would equilibirate over time so no more work could be done.
By this definition of the second law, GHG back radiation to earth does not violate it. Care to elaborate?

Dave Springer
March 1, 2011 7:10 am

davidmhoffer says:
March 1, 2011 at 3:04 am
John of Kent says:
“Infra Red Interacting Gasses (IRIGs) CANNOT heat the earths surface. To do so would mean the colder air is warming the hot ground and that goes against the laws of thermodynamics.”
By the same token insulation in your attic can’t heat your house. But that doesn’t mean attic insulation does nothing at all. It slows down the rate of heat exchange between inside the house and outside the house. That’s what greenhouse gases do except that GHGs are more one-way than attic insulation. They impede very little energy coming from the sun to the earth’s surface but impede a lot of energy going from the earth’s surface to the frigid cold of outer space. This should not be difficult to understand. Arguments to the contrary always have two defining characteristics: they are convoluted and untrue.

pyromancer76
March 1, 2011 7:18 am

Anthony, I wish WUWT would follow Max Hugoson’s advice — atmospheric effect. Truth in science.
Max Hugoson says:
February 28, 2011 at 7:34 pm
PS: Because of Robert Woods 1909 experiment with two miniature “greenhouses”, one with a “rock salt” (i.e., transparent to the longwave IR material) window and the other with a glass window, showing NO MEASURABLE DIFFERENCE in the final equilibrium temperatures in both boxes, we’ve known SINCE 1909 that to ascribe the warming of greenhouses to the allegation of a “one way valve” due to the regular sodium silica glass, is in error.
Real “Meteorological” textbooks for many years have noted this and used the prefered term: “Atmospheric Effect”.
I think the WUWT crowd needs to realize this fact and steadfastly refuse to use the terms “Greenhouse gases” or “Greenhouse Effect”.
Truth needs to win!

mkelly
March 1, 2011 7:21 am

Ira Glickstein
http://www.scribd.com/doc/34962513/Elsasser1942
Again I give you this link to a paper on radiative heating of the atmosphere via IR. It may help.

Steve
March 1, 2011 7:38 am

“Mars is a lot further from the Sun than is the Earth, which is the main reasion it is too cold to support life as we know it, despite all the CO2 in its Atmosphere.”
No, Mars isn’t at a “beyond supporting life” distance from the sun. The Martian atmosphere would be warm enough to support life if it wasn’t so thin , at about 1% the density of Earth’s atmosphere. The density of the atmosphere ties in directly with it’s heat capacity. Mars has little to no magnetosphere, so the solar wind stripped much of the atmosphere away over billions of years.

Dave Springer
March 1, 2011 7:53 am

Enough already with the argument that certain gases that don’t absorb infrared can’t emit it. This is not true for dense gases. The troposphere is a mixture of cold dense gases. Please review Kirchoff’s Laws:
http://www.physics.rutgers.edu/~matilsky/documents/kirchoff.html

Radiation Laws
Kirchoff’s Laws
First Law: A hot solid, liquid, or dense gas emits radiation at all wavelengths (“a continuous spectrum of radiation”). For example, a perfect blackbody does this. If the light were passed through a prism, you would see the whole rainbow of colors in a continuous band.
Second Law: A thin hot gas in front of a cooler background emits radiation at a discrete set of isolated wavelengths. These discrete, isolated wavelengths are called the “emission lines” of the spectrum, because if you were to pass the radiation through a prism, you would see isolated lines of different colors. The whole spectrum is called an “emission-line” spectrum. The wavelengths of the emission lines are unique to the type of neutral atom or ionized atom that is producing the emission lines.
Third Law: A thin cool gas in front of a hotter solid, liquid, or dense-gas background removes the radiation from the background source at special wave lengths. If the resulting radiation were passed through a prism, there would be dark lines superimposed on the continuous band of colors due to the background. These dark lines are called “absorption lines.” The wavelengths of the absorption lines are unique to the type of neutral atom or ionized atom that is producing the emission lines.
If a certain type of gas produces absorption lines at certain wavelengths when it is in front of a hot background, then when that same type of gas is seen in front of a cooler background, it produces emission lines at the exact same wavelengths.
Explanation of Kirchoff’s First Law
Kirchoff’s First Law boils down to blackbody radiation, since solid objects and dense gases emit radiation like blackbodies.
Explanation of Kirchoff’s Second and Third Laws
Thin gases don’t emit or absorb radiation like blackbodies. To understand their emission and absorption, we must consider the structure of atoms, as described by Quantum Mechanics.
The Bohr model of the hydrogen atom: a dense nucleus containing the hydrogen atom’s single proton (and possibly one or more neutrons), surrounded by an electron that can be on one of several different orbits.

Nitrogen doesn’t absorb infrared radiation but it can certainly gain kinetic energy by excited molecules of CO2 and H2O bumping into nitrogen molecules. The kinetic energy gained by the nitrogen molecules will be lost in a continuous blackbody spectrum characteristic of the temperature of the gas.
Any argument to the contrary is simply wrong and ignores basic laws of physics formulated 150 years ago.
What’s hilarious is watching people who have less understanding of classical laws of physics than 19th century physicists start babbling about 20th century quantum mechanics.

Dave Springer
March 1, 2011 8:06 am

Ira Glickstein, PhD says:
March 1, 2011 at 7:19 am

I googled images for “outgoing infrared spectrum” and found this:
http://www.skepticalscience.com/images/infrared_spectrum.jpg
“It should the spectrum looking up from somewhere in the arctic on a clear day and the view looking back down from 20 km. The incoming radiation would be the re-emitted IR from the atmosphere that you wanted. It clearly shows the 7 um, 10 um and 15 um bands Ira is talking about.”

If you’d paid attention to MY comments you’d have found that image months ago. I have posted it several times including last night on THIS thread.
http://www.sundogpublishing.com/fig8-2.pdf
It’s from the 2006 textbook “A First Course in Atmospheric Radiation” by Grant Petty.
I didn’t know you could get a PhD in Obfuscation & Convolution but you’re living proof that it happens.

March 1, 2011 8:34 am

Ira Glickstein, PhD says:
February 28, 2011 at 11:08 pm
What the 100% absorption means is that 100% of the photons in the appropiate bands are 100% likely to be absorbed by an H2O or CO2 molecule before they travel all the way through the Atmosphere. Indeed, I believe, even at the historical 270 or 280 ppm level of CO2, each photon traveled a small fraction of the height of the Atmosphere before being absorbed and re-emitted. So, with the current level of CO2 around 390 ppm, the photons, on average, will travel a shorter distance before getting absorbed and re-emitted. That means that newly emitted longwave radiation from the Earth’s surface will spend more time in the lower reaches of the Atmosphere and therefore contribute to heating the N2 and O2 and other components of the air more than before. Thus, the air nearest the surface of the Earth will, being a bit warmer, re-emit a bit more longwave radiation in all directions, including towards the surface. Hence, more CO2 = a bit more warming. Fortunately, this is a logarithmic process, so subsequent doublings have less and less effect – but they do have an effect.

I’m wondering then if the above is true, then what is the minimum altitude (bold section mine) that actually has any discernable effect on either the earth’s surface or the climate?
Also, while it radiates in all directions, doesn’t whatever becomes warmer rise, moving away from the surface?
Just wondering.

etudiant
March 1, 2011 8:39 am

etudiant says:
February 28, 2011 at 2:18 pm
Relative humidity in the upper atmosphere (300mb level) has fallen from around 55% in 1950 to about 45% now.
Should this not have a material impact on the greenhouse effect? …
What is the source of that data and the accuracy of measurement in 1950? Assuming the change is actual, I would think it would impact the “greenhouse effect”, but I do not know which way because relative humidity considers both the temperature and water content. Are there any more expert than me out there with an answer?
Dr Glickstein,
The source of the data is NOAA, here
http://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl
I do not know how good the pre satellite data is.
Presumably it represents balloon measurements.
The striking thing is the apparent monotonicity of the trend, unlike that at 600mb, which has seen a recovery in recent years.
It does underscore the tremendous complexity of the atmosphere, that this kind of longer term change happens without us even being much aware of it, much less able to explain it.

mkelly
March 1, 2011 8:44 am

Dave Springer says:
March 1, 2011 at 7:53 am
Nitrogen doesn’t absorb infrared radiation but it can certainly gain kinetic energy by excited molecules of CO2 and H2O bumping into nitrogen molecules. The kinetic energy gained by the nitrogen molecules will be lost in a continuous blackbody spectrum characteristic of the temperature of the gas.
Agreed. My point to Cal earlier. If N2 and O2 could not shed energy (trapping it) then we would have a problem.
But that leads to a question: what difference is there between the spectrum of N2 and O2 both at the exact same temperature and radiating. I have not found anything on that.

Ed Scott
March 1, 2011 9:08 am

The peak wavelength of human body emission is at 9500 nm (9.5 microns) and according to the diagram, passes through the Long-wave Window with small loses.
It is interesting to note that nearly all Earth-emitted radiation is between 5 to 30 microns and is centered at about 10 microns.
It seems that most of the thermal energy emitted by Earth and its inhabitants gets a free pass through the Pass-Through Window.
One of the few articles that recognizes the specific heat capacities of the major atmospheric gases – Nitrogen, Oxygen, Ozone and Argon – as well as the atmospheric trace gases – water vapor and Carbon Dioxide.

Oliver Ramsay
March 1, 2011 9:12 am

The charts from skepticalscience are very interesting.
They do not appear to be readings taken at the north pole on January 7th., nor at Tucson on July 9th.
I would be very interested in reading how they are put together.

Bryan
March 1, 2011 9:18 am

Dave Springer
…….”The kinetic energy gained by the nitrogen molecules will be lost in a continuous blackbody spectrum characteristic of the temperature of the gas.”……
Could you provide a chart showing a continuous black body spectrum for nitrogen gas.
I dont think such a thing exists.

Philip Peake (aka PJP)
March 1, 2011 9:24 am

@Ira — sorry about all that extra work 🙂
I agree that adding more CO2 molecules will increase the chances of photons of a particular energy impinging upon another molecule with an energy band exactly matching that of the photon energy (another CO2 or H2O molecule) and so slowing the progress of that “packet” of energy towards space and freedom.
In short, it will improve the insulation properties of the atmosphere.
As you say, because of the statistical chance of hitting another molecule, as the concentration of molecules increases, so will the chance of such an encounter, but the effect is, indeed, logarithmic in nature (Log base e, not Log base 10).
Look ONLY at CO2 and you will find that a doubling does have some headroom to make a measurable difference. However, if you treat CO2 and H2O molecules as effectively the same, which they are in this context, then a doubling of CO2 amounts to a much, much smaller fractional increase when considering all H2O and CO2 molecules combined, and I would be exceedingly surprise if you could actually measure any difference.

Bryan
March 1, 2011 9:29 am

Ira Glickstein
The famous experiment by R W Wood proved two things;
1. Glasshouses(greenhouses) heat up by stopping convection.
2. The heating radiative effect at atmospheric temperatures is so small as to be negligible for most practical purposes.
People tend to forget the second part.

Tim Folkerts
March 1, 2011 9:37 am

Dave Springer says: March 1, 2011 at 7:53 am
Enough already with the argument that certain gases that don’t absorb infrared can’t emit it.

At thermal equilibrium, the emissivity of a body (or surface) equals its absorptivity.
http://en.wikipedia.org/wiki/Kirchhoff%27s_law_of_thermal_radiation
The emissivity characterizes the radiation or absorption quality of nonblack bodies.
http://www.answers.com/topic/emissivity
The rate of electromagnetic radiation emitted at a given frequency is proportional to the amount of absorption that it would experience by the source. Thus, a surface that absorbs more red light thermally radiates more red light.
http://en.wikipedia.org/wiki/Thermal_radiation

A black body absorbs and emits all frequencies of light perfectly. A non-black body will absorb and emit light less well at some (or all) frequencies. But the frequencies where it absorbs poorly are the same as the frequencies where it emits poorly. Thus a material (like the atmosphere) that absorbs some wavelength of light (say 10 um) poorly will also emit that wavelength poorly.
Since you agree that N2 absorbs 10 um light poorly, then the only conclusion is that it also emits 10 um light poorly.
In fact, the very image you reference at http://www.sundogpublishing.com/fig8-2.pdf shows that there is almost no radiation coming down at 8-12 um. If the N2 was indeed emitting significant amounts of thermal radiation at those wavelengths, where is it? I see the (nearly) black body radiation above and below those limits due to the H2O and CO2 (and other GHGs) which can (almost perfectly) absorb those wavelengths.

Tim Folkerts
March 1, 2011 9:49 am

Bill Illis says: March 1, 2011 at 5:14 am
But the Sun emits mostly like a blackbody.
It is not being emitted in the Hydrogen frequencies only, it is emitting across the entire spectrum close to what the blackbody curve predicts.

Quite true. But the circumstances were quite different from what I was describing. The sun is not a single H atom, but a huge collection of ionized H+ and electrons. Ionized H+ cannot have a Balmer spectrum because it has no orbiting electron. (And as you point out, non-ionized H in the cooler outer layers can and does then absorb the Balmer lines, making them dimmer than other wavelengths). Certainly a large enough collection of ionized CO2 or N2 or any other gas could emit a significant continuous spectrum like the sun does. But that does not describe the situation in the earth’s atmosphere.

March 1, 2011 9:56 am

Peter Taylor;
It took me a long time to realise that the Radiative Forcing (RF) that is at the heart of the model calculations is centred on a notional point toward the top of the troposphere…defined by the temperature at which the earth will reradiate the balancing energy – which is -19 C and about 10km up>>>
This was one of my very first epiphanies in regard to the IPCC numbers. They keep quoting 3.7w/m2 and 1 degree, but a quick SB Law calculation versus temp at earth surface doesn’t support that. From your post it sounds like you couldn’t find the supporting docs in AR4, but I did. I’d have to dig like crazy because it was a long time ago, but from memory:
IPCC calculates sensitivity at the “theoretical black body” temperature of earth. I thought it was -15, but could very well have been -19
They specificaly state that surface temperature changes cannot be directly related to changes in RF. In fact, they even say it is possible that a change in RF results in climate change, but potentially NO surface temp change.
The implication that CO2 is linear was very carefully worded, but turned out to be a reference to a small change of some sort where treating it as linear was a reasonable approximation. BUT, if you go to the section on ECONOMIC scenarios, that make it VERY difficult to work the numbers backward to CO2 concentrations, but the log functions are very clear in those sections.
This subterfuge is very misleading, deliberately so, and I’ve remarked on it often. If someone wants to write a detailed expose, I’ll be happy to go scrounge up all the references even if it means reading the whole d*** thing again.

Phil.
March 1, 2011 10:15 am

Slacko says:
March 1, 2011 at 6:19 am
Tim Folkerts says:
February 28, 2011 at 7:23 pm
“However, it is an observed fact (supported by theory) that monatomic gases (like argon) or symmetric diatomic gases (like N2 and O2) do not have vibration modes or rotation modes that would allow them to absorb (or emit) IR photons.
… IR is not absorbed or emitted by N2 & O2.”
A hot body that won’t radiate infrared?? That’s gotta be the best-kept secret in physics, if it’s true.

A gas is not a hot body and gases that don’t have a dipole, like N2, O2 and Ar, don’t emit IR, this has been known to physics and chemistry for quite some time. See Herzberg G., ‘Molecular spectra and molecular structure. I. Spectra of diatomic molecules’, New York: Van Nostrand Reinhold, 1950, the classic text on the subject.
mkelly says:
March 1, 2011 at 8:44 am
Dave Springer says:
March 1, 2011 at 7:53 am
“Nitrogen doesn’t absorb infrared radiation but it can certainly gain kinetic energy by excited molecules of CO2 and H2O bumping into nitrogen molecules. The kinetic energy gained by the nitrogen molecules will be lost in a continuous blackbody spectrum characteristic of the temperature of the gas.”
Agreed. My point to Cal earlier. If N2 and O2 could not shed energy (trapping it) then we would have a problem.
But that leads to a question: what difference is there between the spectrum of N2 and O2 both at the exact same temperature and radiating. I have not found anything on that.

As stated above absolutely wrong, the only way that N2 and O2 molecules can shed energy is by collisional exchange with CO2, H2O etc. molecules which can then radiate.
Here’s a low resolution spectrum showing N2, O2 and CO2, I’ve left out H2O for simplicity but it occupies the 5-10 micron region at a similar intensity to CO2 (10^-20). Note that the vertical scale is log base 10!
http://i302.photobucket.com/albums/nn107/Sprintstar400/CO2N2O2.png

cal
March 1, 2011 10:45 am

mkelly says:
March 1, 2011 at 8:44 am
Dave Springer says:
March 1, 2011 at 7:53 am
Nitrogen doesn’t absorb infrared radiation but it can certainly gain kinetic energy by excited molecules of CO2 and H2O bumping into nitrogen molecules. The kinetic energy gained by the nitrogen molecules will be lost in a continuous blackbody spectrum characteristic of the temperature of the gas.
Agreed. My point to Cal earlier. If N2 and O2 could not shed energy (trapping it) then we would have a problem.
But that leads to a question: what difference is there between the spectrum of N2 and O2 both at the exact same temperature and radiating. I have not found anything on that.
OK so please describe in detail the mechanism by which N2 and O2 radiate this energy if it is not by the movement of electrons between different energy states (as a consequence of the vibrational modes of the molecule) which causes the characteristic absorption and emission lines.
I gave the explanation to your supposed paradox in my original comment. The N2 and O2 molecules gain energy and lose energy by collision with CO2, H2O and other greenhouse gases. There is a small amount of radiation as well but it is negligible in the context of the greenhouse gas emissions. Just look at the emission spectra of N2 and O2 and compare it with the IR spectrum that Ira gives. Further all bodies above absolute zero radiate but the emissivities vary dramatically. A black body is 100% efficient a white body (which cannot really exist) is 0% efficient. N2 and O2 are closer to being white bodies at these temperatures.

Brian H
March 1, 2011 11:15 am

I thought it was still a matter of dispute whether a gas (the molecules in a gas) behaved/radiated according to BB “laws”. There seem to be very positive opinions being asserted above that hinge on that specific issue.
BTW Ira, I’ve just gone thru the first part of your novel, and I wonder if you still “believe” the scenarios and causalities for climate behavior and fluctuation you posit and “explain” in Chapter 1. The verbiage circles round and round, but boils down to domination by CO2 changes, with some drastic natural and not-so-natural interventions and intervening events forcing it back down to “normal” levels.
Which, IMO, is alla buncha hooya.

Domenic
March 1, 2011 11:43 am

to Phil and Cal
Nope. The full characteristics of N2 and O2 in the long wavelength IR have never been actually tested.
I have been looking for long wavelength IR real test data for both N2 and O2 , and cannot find it.
The only ‘graphs’ out there are calculated from models, not from lots of actual test data. With 20+ years in IR measurement and quantification experience, I don’t trust the graphs out there.
There are no such things as ‘white bodies’ out there. The opposite of a ‘blackbody’ is a ‘perfect mirror’, not a ‘white body’.
The only materials that exhibit close to ‘perfect mirror’ thermal radiation properties are pure metals. Highly polished gold, aluminum, etc, or their atoms.
From my direct IR measurement experiences, materials with nitrides (N, N2, etc) and oxides (O, O2, etc) in their surface composition have very high emissivity, closer to blackbodies. Thus they have very small reflective components. Metal oxides are perfect examples. Bare metals are highly reflective. But let the surface oxidize heavily, and their IR reflection capability disappears…and their emittance approaches a blackbody.
There is something very fishy in the spectral graphs bandied about from calculations regarding the emittance and reflectance of N2 and O2. They are not metals.
Both N2 and O2 must be tested thoroughly in the long wavelengths and not guessed at.

Disputin
March 1, 2011 12:07 pm

Many thanks, Ira, for a clear explanation, and I understand that you have only attempted to describe the radiative effects in this post.
My view is that the term ‘Greenhouse Effect’ is dead right because it describes exactly how a greenhouse does not work. A real greenhouse works just as well with polythene, styrene or, classically, rock salt windows because, although the blocking of long wave IR is real it’s irrelevant compared with the greenhouse’s blocking of the convective currents which are the main mechanism for removal of hot air, directly and by evaporation.
Similarly, although I’m sure there is a radiative effect which would be active in a static atmosphere, the real atmosphere is anything but static, being thoroughly turbulent and full of convective cells. Radiation thus only comes into effect at the top of the troposphere, where the density of all gases is too low to do much blocking.
In my view the talk of radiative physics is a waste of time since it’s an extremely minor effect.

Oliver Ramsay
March 1, 2011 12:08 pm

Domenic says:
March 1, 2011 at 11:43 am
The only materials that exhibit close to ‘perfect mirror’ thermal radiation properties are pure metals. Highly polished gold, aluminum, etc, or their atoms.
————————-
I have read that variations in emissivity between substances (except for metals) are largely due to the topography of the surfaces. I imagine that must also be true for metals, since the differences between polished and unpolished surfaces are so marked.
I’m suprised that our coarse rubbing with abrasives is able to produce such a strong effect, even though I have seen it with my own eyes. ???

mkelly
March 1, 2011 12:24 pm

Phil. says:
March 1, 2011 at 10:15 am
“As stated above absolutely wrong, the only way that N2 and O2 molecules can shed energy is by collisional exchange with CO2, H2O etc. molecules which can then radiate.”
Thanks for the information Phil. Your photo while nice does not answer the question of N2 and O2 at the same temperature. Since temperature drives the emittion frequency will they both be the same? I math (Weins Law) says yes, but I have found no info on the subject.
By the way by your statement above you are in the camp that says without GHG we would be a very hot world indeed. Not at -18 C. Once a N2 or O2 molecule was heated via conduction with the ground it would stay heated for a very long time with no H2O or CO2 to reduce its energy. Correct?

George E. Smith
March 1, 2011 12:28 pm

“”””” Scottish Sceptic says:
February 28, 2011 at 2:56 pm
“Other aspects that control the temperature range at the surface of the Earth are at least as important and they include convection (winds, storms, etc.) and precipitation that transfer a great deal of energy from the surface to the higher levels of the Atmosphere.”
I would suggest CO2 in the atmosphere is much like the “correct” expanation of the Crookes radiometer (the black and white rotating thing in a glass vacuum bulb). “””””
I believe that the original conception of the Crookes Radiometer, was to demonstrate “Radiation pressure” The Kinetic energy of Photons impinging on a surface.
The idea was that the blackened surface would absorb the photons, setting up a pressure on the black side of the paddles. The shiny side of the paddles however would not absorb the photons but would reflect them, creating twice the momentum change, so the paddles would rotate, with the shiny side pushing the black side before it.
Of course it rotates the other way instead; and the reason is that the black side is slightly hotter than the shiny side, and it heats the residual gas molecules close to the surface more than the shiny side does thereby creating a higher pressure on the black side. They couldn’t create a high enough vaccuum to get the radiation pressure to dominate the residual gas differential pressure.

Sensor operator
March 1, 2011 12:32 pm

Wow! There are soo many problems and issues being thrown around that it is nearly impossible to address everything. As someone with a degree in physical science (including physics and astronomy) I guarantee you cannot learn the basics from one page, let alone all of the complexities, e.g. spectroscopy.
I just want to cover four simple items and see if I can provide other insight later:
1) Steve at 141 is correct: The nearly absent atmosphere is the reason Mars is so cold. Other comparisons: the Moon vs the Earh (basically the same distance from the Sun but no atmosphere on the Moon) and Mercury vs Venus (Venus is further away but with an extemely dense, CO2 heavy atmosphere which causes Venus to be much hotter than Mercury).
2) On a large scale (planetary), the method of heat transfer is radiation. There may be convection and conduction within the atmosphere (up to about 10 Km as found by E. O. Hulburt in 1931), but between the Earth (including the atmosphere) and “space”, heat is transferred via radiation since space is a vacuum (you need matter for conduction and convection, also shown by Hulburt in 1931).
3) CO2 and H2O
Ugh, this comes up soo often it is getting tiresome. So let’s look at two pieces of information.
3a) Absorption by components
Please look at the following picture showing the absorption from CO2 and H2O, as well as other constituents. While water is a broad absorber of long wave IR radiation (greater than 10 microns), it is not complete. But look at CO2. This is very important. There is a major absorption feature between ~13-20 microns which is very good at absorbing LWIR radiation. This is important becasue H2O does not completely absorb the radiation in this wavelength region. So when CO2 levels increase, it further impedes LWIR radiation from escaping the atmosphere. This is even more important since according to Planck’s law, a blackbody at the Earth’s surface temperature will radiate in this wavelength region. While the Earth may not be a blackbody, it does radiate in this spectral region.
3b) Composition of atmosphere relative to CO2 and H2O
H2O is primarily limited to being located close to the surface of the Earth and is not well mixed into the entire atmospheric column, unlike CO2. However, when we look at things spectrally, it does not matter if the gas we are looking through is localized in a small area or spread out through a larger area/volume (ignoring clouds of course). It will have the same effect. When we measure gases using spectral instruments, we need to take into account the distance from the source to the sensor. We calculate the amount of the gas we see and divide by the distance and get an average over that distance. Same is true when looking down from a satellite towards the Earth. When we consider the entire column we find:
H2O: ~0.40%
CO2: ~0.04%
While H2O is higher than CO2, it is not orders of magnitude larger. The challenge is that the H2O amount is not changing by 100%. Remember from 3a, CO2 is absorbing outgoing radiation where H2O is not and the amount of CO2 is increasing.
4) Be careful with these plots and simple explanations. Total absorption and opaque are not quite the same, i.e. if 100% is already absorbed than more CO2 cannot be a problem. The graph at the top of the page suggests that the atmosphere is a single step from Earth to space. In reality, models use multiple levels to account for the differences in gas constituents at various heights.
Last lesson: Be very careful with LWIR. Most people are okay with near IR and short wave IR since this radiation is identical to visible sunlight, which we are accustomed to as humans since our eyes are optimized for that region. In this part of the spectrum, we talk about reflection and absorption. But when we head towards long wave IR, you have absorption/emission, transmission and reflection. It is a somewhat messier region that can be easily confused. Most people familiar with LWIR come from a lab setting using instruments in a controlled setting. But when you start looking at/using the atmosphere, it becomes a much more difficult problem.
Hopefully NASA’s Glory satellite may help answer more questions when it finally launches.

Mark Nodine
March 1, 2011 12:35 pm

Thanks, Ira, for an interesting post.
I think there is an important point, however, on which your analysis is misleading. I agree with George E. Smith (February 28, 2011 at 3:23 pm) that the IR absorption occurs by exciting the vibrational modes of GHGs. The reason that N2 and O2 and H2 do not absorb IR is not that they have no dipole (since neither does CO2), but because, being diatomic, they have no asymmetric vibrational modes, which are the ones that absorb in the IR range. George is right in saying that the vast majority of the absorbed light rays are immediately reradiated and do not have time to affect the thermal distribution of the surrounding gases. The reradiating becomes even more preponderant the farther up in the atmosphere you get because of the decreasing density of gases with height. So Ira’s assertion that GHGs exert a large thermal effect on the atmosphere seems to me to be a bit unlikely, except possibly in the lower troposphere. The other thing to consider is that where thermal transfer does take place, any blackbody radiation that occurs will be at the new temperature rather than at the original temperature. Because of adiabatic lapse (think PV=nRT), the temperature of the atmosphere drops rather quickly as a function of height until you get up to the thermosphere, where there is a large rise in temperature, but so rarefied an atmosphere as not to have any significant impact on the atmospheric windows. So even assuming you could model radiation from a layer of atmosphere as if it were a black body (which it is not), the distribution is shifted toward yet longer wavelengths than are radiated by the earth.
My main point is that my substantial physics training leads me to believe that the main impact of GHGs is vibrational excitation followed by return to the ground state, emitting a photon of the same wavelength but in a random direction, rather than by any significant transfer of internal vibrational energy to thermal energy of surrounding molecules.

Domenic
March 1, 2011 12:37 pm

Hi Oliver,
I like these discussions because they have been encouraging me to remember my IR skill set.
Yes, it’s a surface condition effect. And it is quite dramatic.
But what I suddenly realized, from this discussion is something that I had not thought of before.
The stars. Outer space.
Do you realize that it impossible from earth to know whether all the ‘stars’ that are seen in the sky, or from space, are indeed really ‘stars’ and not ‘reflections’ from massive pure metallic bodies, or perfect reflectors, of nearby true stars?
It is literally impossible to know from a distance. Impossible.
Now that is wild.
I have never seen that idea looked at in astrophysics.
But from a radiational physics point of view, it is entirely possible.

Richard Smith
March 1, 2011 12:39 pm

There is confusion on this thread about the meaning of the term ‘greenhouse effect’. Some of the commenters seem to think that it is merely something that reduces the rate of heat loss (and they draw analogies with blankets and igloos which nobody disputes). But the greenhouse effect according to climate ‘science’ is not the insulation of a blanket or a reduction in the rate of cooling, but a positive addition of heat (33C or more) because of ‘backradiation’. If this theory were true it would mean that the Earth emits more energy than it receives. This is a contravention of the laws of thermodynamics. It is based on the fallacy that if the escape of heating is blocked, then the temperature will continue to rise until a ‘radiative equilibrium’ is reached and the heat bursts through the barrier. It is claimed that the laws of thermodynamics are not broken because the emission at the top of the atmosphere is equal to the incoming solar radiation. But, like the theory of the runaway greenhouse, it is a fallacy. If it were true we could generate huge amounts of energy from a small input simply by placing an infra-red barrier around a radiator – just tap some of the heat off at regular intervals – free energy.

George E. Smith
March 1, 2011 1:05 pm

“”””” _Jim says:
February 28, 2011 at 3:45 pm
George E. Smith February 28, 2011 at 3:23 pm :

So the atmosphere does radiate a black body like thermal spectrum, and the presence of the gHG molecules simply means that there will be bands of that continuum emission, that are also captured by the GHG molecules, as well as the emissions from the surface.
I’ll wait to see how this is adjudged.
(IR Spectroscopy explaining spectral response regarding gas molecule vibrational modes would seem to indicate otherwise.) “””””
Jim needs to take remedial English Reading courses. IR Spectroscopy indicates nothing of the sort.
The IR Spectroscopy item you cited, refers to ABSORPTION SPECTROSCOPY which as it properly indicates, relates to RESONANCE MODES which are indeed characteristic of specific molecules, and their excited state energy levels.
No where did I make any statement that is inconsistent with this; it is the reason we talk about the “15 micron” or 666 cm^-1 degenerate bending mode of the linear CO2 molecule. It is degenerate since there are two identical and indistinguishable modes at right angles to each other; each of which can gather its own photon.
But the question which you chose to challenge, is the quite different THERMAL SPECTRUM EMISSION; which has nothing whatsoever to do with atomic or molecular structure or energy levels. It is a classical physics consequence of the accelerations of electric charge; which according to Maxwell’s equations must (and do) result in the radiation of an EM wave (or photon if you wish; which has a continuous energy spectrum; not a quantized one. Ordinary atoms, once ionized by the removal of one or more electrons, also emit a continuum EM spectrum, which is not quantized, because a newly captured free electron can have any initial energy before being captured by the ion.
The accelerations of Electric charge in molecular collisions, are entirely unpredictable as the the redistribution of momentum and energy; although one can talk statistically about expected distributions.
One can learn a thing of two from the Particle Accelerator Physicists. The Stanford two mile long electron linear accelerator is one of if not the most powerful electron accelerators in the world. It is linear, because then the only acceleration the electrons see, is due to the accelerating electric (traveling) waves in the beam line. On the other hand circular track accelerators, have to steer the beam around corners continuously to get them to repass through the accelerator gaps, and gain more energy. To compensate for this increased energy, the bending magnet fields have to increase synchronously with the particle energy, to maintain them in the correct orbits. Since the charged particles are traveling in a circle, they are subject to a continuous acceleration, since acceleration is a change in velocity and velocity is a vector quantity, having a direction as well as a “speed”.
So particles in a circular accelerator continuously radiate, EM energy as the go around the track. Well pedantically, the path is a number of curved arcs, interleaved with a number of straight sections, and it is only in the arced sections that the particles radiate.
So the reason why proton beams can be accelerated in a circle, and electrons can’t (beyond certain energies, is that the proton is far more massive than the electron.
So consider two neutral atoms (or molecules) colliding. Each molecule or atom is electrically neutral, so the electrons will go more or less, where the protons in the nucleus goes (on average), but in the process of collisions and recoil of the particles, the more massive nuclei consisting of Protons, and Neutrons, undergo far lower accelerations, than do the much lighter electrons; so even though and single atom or molecular is electrically neutral, in collision, the electrons undergo much higher accelerations than do the Protons or nuclei; so just as in the particle accelerator, it is the electrons that radiate the EM wave energy, and the much smaller opposing field due to the proton accelerations does not compensate. So one can practically ignore the proton positive charges, and consider only the acceleration of the net electron charge to figure out the radiated EM fields.
The thermal radiation continuum depends only on the Temperature, and has a BB like spectrum, that does not depend on the atomic or molecular species; only on the Temperature.
Some of you people need to get your noses out of facebook, and wiki, and hit some Physics books, to learn what you should have learned around the 8th grade.
Nothing in the IR Spectroscopy paper you cited is inconsistent with that; they talk ONLY about absorption spectra; not emission.
And Kirchoff’s law applies only in equilibrium, and the atmosphere is never in equilibrium.

George E. Smith
March 1, 2011 1:18 pm

“”””” Tim Folkerts says:
March 1, 2011 at 9:37 am
Dave Springer says: March 1, 2011 at 7:53 am
Enough already with the argument that certain gases that don’t absorb infrared can’t emit it.
At thermal equilibrium, the emissivity of a body (or surface) equals its absorptivity.
http://en.wikipedia.org/wiki/Kirchhoff%27s_law_of_thermal_radiation “””””
“”””” At thermal equilibrium, the emissivity of a body (or surface) equals its absorptivity. “””””
“””””At thermal equilibrium, ……. “””””
Can people stop citing Kirchoff’s law, and then TOTALLY ignoring it (spectral) emmissivity equals (spectral) absoptance, ONLY in “THERMAL EQUILIBRIUM ”
Earth’s atmosphere is NEVER in thermal Equilibrium; it has a continuous energy input from somewhere else, and a continuous energy output to someplace else.
So Kirchoff’s Law NEVER applies to earth atmospheric situations; EMISSIVITY NEVER EQUALS ABSORPTANCE.

kbray in california
March 1, 2011 1:23 pm

[[[ Ira Glickstein, PhD says:
March 1, 2011 at 6:01 am
…Your analogy of the black balls in the pool does not work because the mechanism is not at all like that of the “greenhouse effect” GHG in the atmosphere. There is more H2O (the main GHG) in the Atmosphere than CO2, but the percentage of H2O is also miniscule, yet, the tiny percentage of GHGs (mostly H2O but also CO2) are responsible for the Earth being at livable temperatures. ]]]
OK Ira,
I agree that Earth’s Atmosphere helps make our Earth livable. I think water in all three states, solid, liquid, and gas, clearly plays the major role. The alleged “CO2 effect” is critical that it be accurately quantified, as it is being considered a “problem” and will cost us all dearly (money) if current politicians impose their planned restrictions.
I want to shrink the “alleged CO2 effect” to a simple provable visual experiment that the average layperson can easily absorb. Some of the material presented in this wonderful blog is quite advanced and beyond the expertise of many lay readers.
How about this…..
1) Chill 1 bottle of distilled water and 1 bottle of CO2 injected mineral water in the refrigerator (to keep the CO2 in solution).
2) Find 2 identical glass or plastic bottles with a screw top that seals.
3) Place a thermometer upsidedown in each bottle so the bulb won’t be in the liquid.
4) Fill each bottle half way with identical volumes, one with distilled water, the other with the CO2 impregnated mineral water.
5) Secure the cap and place in full sun on the window sill.
6) Keep room temperature just slightly below the thermometer temperature as it changes.
7) If CO2 really does have a big influence in keeping Earth warmer, at some point in the experiment either during the day, or at sunset, or in the evening, or at night, the air above the mineral water should be warmer.
Both will have a mix of normal atmosphere and water vapor, but the mineral water will have released additional CO2 into its “atmosphere”, boosting its “greenhouse effect” that will keep retained/reflected heat in its sealed environment.
Remember to keep the room temperature just slightly below the bottle temperature to keep any heat transfer influence from the room air at a minimum.
If there is a “CO2 effect” it should show up here on the thermometers.
How about this one Ira?

izen
March 1, 2011 1:31 pm

@-mkelly says:
March 1, 2011 at 12:24 pm
“By the way by your statement above you are in the camp that says without GHG we would be a very hot world indeed. Not at -18 C. Once a N2 or O2 molecule was heated via conduction with the ground it would stay heated for a very long time with no H2O or CO2 to reduce its energy. Correct?”
If I may reply as someone who would agree with Phil’s spectralcalc picture of the emissivity of N2 and O2 as several orders of magnitude smaller than that of CO2 for present surface temperature. I understand that such values are calculated from quantum mechanical first principles, perhaps those that doubt them can find direct measurements that contradict that. But the research on radiative transfer carried out in connection with heat sensor/seeking systems for military purposes would seem to make it unlikely that any such major error has gone unnoticed.
Without GHG we would not be hotter because the N2 and O2 atmosphere has a lower emissivity. They could only warm by conduction with the surface to a temperature equal to the surface. Without GHG the surface would lose energy by IR radiation faster because there is no downwelling or back radiation from the atmosphere. Therefore it would be colder, and could not heat up the N2 and O2 molecules to any greater temperature than it had reached.

George E. Smith
March 1, 2011 1:39 pm

“”””” Mark Nodine says:
March 1, 2011 at 12:35 pm
Thanks, Ira, for an interesting post.
I think there is an important point, however, on which your analysis is misleading. I agree with George E. Smith (February 28, 2011 at 3:23 pm) that the IR absorption occurs by exciting the vibrational modes of GHGs. The reason that N2 and O2 and H2 do not absorb IR is not that they have no dipole (since neither does CO2), but because, being diatomic, they have no asymmetric vibrational modes, which are the ones that absorb in the IR range. George is right in saying that the vast majority of the absorbed light rays are immediately reradiated and do not have time to affect the thermal distribution of the surrounding gases. “””””
Well Mark, you were doing ok until you said this:- “”””” George is right in saying that the vast majority of the absorbed light rays are immediately reradiated and do not have time to affect the thermal distribution of the surrounding gases. “””””
Because absolutely never in my life have I ever said any such thing; the exact opposite in fact.
The CO2 (or other GHG molecule) certainly absorbs specific LWIR energies, according to the energy levels of its excited molecular states; ” BUT ” in the lower atmosphere it NEVER (hardly ever) has enough time to re-radiate that absorbed Photon, at the same energy and frequency (wavelength). Molecular collisions happen many thousand times faster, than spontaneous emission at specific (CO2) frequencies. The energy is lost in thermalization collisions, which warm the ordinary gases of the atmosphere. From that time on, the GHG gas molecule has no influence whatsoever on what happens. The (slightly heated) atmospehric gases now radiate a complete thermal spectrum continuum, depending ONLY on the atmospheric Temperature; AND THEN the CO2 or other GHG molecule can re-engage with THAT spectrum, and once again carve out its specific absorption band chunk.
The proof of this is in the satellite (and calculated) LWIR spectra of the earth. They are BLACK BODY LIKE SPECTRA with the GHG absorption band partly missing (attenuated) by the GHG molecules.
If the only LWIR emission from the atmopshere was from the GHG molecules, itwould be ONLY at th4e specific GHG resoanance absorption band frequencies; and it is not; it is a full BB like spectrum.
You have to note that the actual spectrum is the overlaying Temperature BB spectrum, MODIFIED by the spectral radiant emissivity of the radiating material.
Since a thin gas layer, has few molecules, it has a correspondingly low emissivity.
A 50 Angstom gold film, also has a correspondingly low emissivity; but of course higher than the gas layer, because it still has a greater atomic or molecular density.
There is nothing in the phase transition from solid ice, or liquid water, to H2O vapor by sublimation or evaporation; that suddenly turns off the ability of those molecules to emit a BB like thermal continuum radiation spectrum according to Planck formula and other applicable laws (don’t forget the emissivity).
But I have never said the the atmospheric LWIR spectrum consists of the GHG resonance absorption frequewncies only.
That condition is approached in the stratosphere, when molecular mean free paths, and intercollision times become long compared to the lifetimes of the excited states. Then the spontaneous emission can occur; but the molecular density is so low, that it cannot be a significant contributor to the total earth LWIR emission spectrum.

George E. Smith
March 1, 2011 1:41 pm

“”””” izen says:
March 1, 2011 at 1:31 pm
@-mkelly says:
March 1, 2011 at 12:24 pm
“By the way by your statement above you are in the camp that says without GHG we would be a very hot world indeed. Not at -18 C. Once a N2 or O2 molecule was heated via conduction with the ground it would stay heated for a very long time with no H2O or CO2 to reduce its energy. Correct?”
If I may reply as someone who would agree with Phil’s spectralcalc picture of the emissivity of N2 and O2 as several orders of magnitude smaller than that of CO2 for present surface temperature. I understand that such values are calculated from quantum mechanical first principles, perhaps those that doubt them can find direct measurements that contradict that. “””””
Those specracalc images that Phil posted, are ABSORPTION SPECTRA; NOT EMISSION SPECTRA.

Domenic
March 1, 2011 2:00 pm

to Izen
you wrote: “But the research on radiative transfer carried out in connection with heat sensor/seeking systems for military purposes would seem to make it unlikely that any such major error has gone unnoticed.”
Heat seeking systems are ridiculously simply compared to accurate quantification and complete summation of thermal radiation properties for specific gases.
Heat seeking sensor systems only need a ‘window’ or two, or three to locate a target.
Heat seeking sensor systems are qualitative in nature, not quantitative. The military doesn’t care much about the details. They just want to find and lock onto the target.
If you had any experience with quantifiable IR, you would know this.
And that is one of the biggest problems. Much research about atmospheric IR has been done by the military in order to locate and track heat signatures. But that data is really of minimal use when absolute quantification is necessary for establishing real world temperature effects of gases in the atmosphere regarding ‘greenhouse effects’.

kbray in california
March 1, 2011 2:01 pm

[[[Ira said:
“Mars is a lot further from the Sun than is the Earth, which is the main reasion it is too cold to support life as we know it, despite all the CO2 in its Atmosphere.”
Steve says:
March 1, 2011 at 7:38 am
No, Mars isn’t at a “beyond supporting life” distance from the sun. The Martian atmosphere would be warm enough to support life if it wasn’t so thin , at about 1% the density of Earth’s atmosphere. The density of the atmosphere ties in directly with it’s heat capacity. Mars has little to no magnetosphere, so the solar wind stripped much of the atmosphere away over billions of years. ]]]
kbray asks: How much atmosphere on Mars do you need to produce the “runaway greenhouse effect”(think Hansen) to get Venus-like temperatures ? Mars already seems to have enough CO2 in the atmosphere being measured in the high 90%. Maybe at high concentrations CO2 has a “protective effect” and actually reverses the greenhouse effect. After all, as per Hansen’s ideas, it should be hotter than blazes on Mars shouldn’t it ?… Maybe we can reverse “global warming” by producing MORE CO2 ? /sarc.

George E. Smith
March 1, 2011 2:08 pm

“”””” Dave Springer says:
March 1, 2011 at 7:53 am
Enough already with the argument that certain gases that don’t absorb infrared can’t emit it. This is not true for dense gases. The troposphere is a mixture of cold dense gases. Please review Kirchoff’s Laws:
http://www.physics.rutgers.edu/~matilsky/documents/kirchoff.html
Radiation Laws
Kirchoff’s Laws
First Law: A hot solid, liquid, or dense gas emits radiation at all wavelengths (“a continuous spectrum of radiation”). For example, a perfect blackbody does this. If the light were passed through a prism, you would see the whole rainbow of colors in a continuous band.
Second Law: A thin hot gas in front of a cooler background emits radiation at a discrete set of isolated wavelengths. These discrete, isolated wavelengths are called the “emission lines” of the spectrum, because if you were to pass the radiation through a prism, you would see isolated lines of different colors. The whole spectrum is called an “emission-line” spectrum. The wavelengths of the emission lines are unique to the type of neutral atom or ionized atom that is producing the emission lines.
Third Law: A thin cool gas in front of a hotter solid, liquid, or dense-gas background removes the radiation from the background source at special wave lengths. If the resulting radiation were passed through a prism, there would be dark lines superimposed on the continuous band of colors due to the background. These dark lines are called “absorption lines.” The wavelengths of the absorption lines are unique to the type of neutral atom or ionized atom that is producing the emission lines.
If a certain type of gas produces absorption lines at certain wavelengths when it is in front of a hot background, then when that same type of gas is seen in front of a cooler background, it produces emission lines at the exact same wavelengths.
Explanation of Kirchoff’s First Law
Kirchoff’s First Law boils down to blackbody radiation, since solid objects and dense gases emit radiation like blackbodies.
Explanation of Kirchoff’s Second and Third Laws
Thin gases don’t emit or absorb radiation like blackbodies. To understand their emission and absorption, we must consider the structure of atoms, as described by Quantum Mechanics. “””””
Well I found this citation from Dave Springer; about “Kirchoff’s Laws”.
Would people please read what Rutgers University says about those laws; and please take note of all of the words, in their explanation.
Notice their reference to THIN HOT GASES and THIN COLD GASES. Note the “”””” THIN “””””
Those nice Balmer spectra and the like from Mercury vapor lamps or Sodium lamps and the like are observed in VERY LOW DENSITY gases, where the mean time between molecular or atomic collisions is much longer than the lifetimes of the excited states, so that spontaneous emission can occur; only then do you get the bright line spectra as seen in those HOT gases.
But the earth’s lower troposphere is neither low density nor hot; it is 288 K on average worldwide (so they tell us), and the molecular collision rates are thousands of times faster than the excited state lifetimes, so spontaneous emission almost never occurs in the lower troposphere.
But the molecular velocities of thermal motion of atoms or molecules; and especially molecules being more massive, are way lower than the vibrational mode velocites of the excited state resonances, so the resulting electron accelerations in intermolecular collisions, are much lower, hence the magnitude of the thermal radiation fields is way down in the mud, which is why it is so hard to observe.
But the fact remains, that the spectrum which is supplying the GHG resonance energies , is akin to that radiated by an ordinary yard brick or a bottle of water, at room Temperature. That radiation is 10,000 times lower in radiant emittance, than the radiation form an ordinary 100 Watt “heat lamp”, that emits radiation that is absorbed by human tissue and registers itself as what we call heat; and it does so, because we are mostly water, and absorb strongly at the 1 micron wavelength of the heat lamp emissions.
Humans do NOT perceive 10 micron 288 K radiation as producing heat, because it is only 400 W/m^2, and not 4 million W/m^2 that the heat lamp emits.
But jsut because we don’t sense it, does not mean the atmospheric gases are not emitting it.

RJ
March 1, 2011 2:15 pm

Izen
A good question. How would O2 and nitrogen lose energy if there were no GHGs in the atmosphere.
I assume this means that nitrogen and oxygen molecules can in fact lose energy by conduction (that mostly occurs at lower attitudes) or by radiating IR energy out into space at high attitudes.

Vince Causey
March 1, 2011 2:20 pm

Richard Smith,
You say “But the greenhouse effect according to climate ‘science’ is not the insulation of a blanket or a reduction in the rate of cooling, but a positive addition of heat (33C or more) because of ‘backradiation’. If this theory were true it would mean that the Earth emits more energy than it receives. This is a contravention of the laws of thermodynamics.”
Surely, if temperatures are rising, (as posited by the GHG hypothesis) it must mean the exact opposite – namely that the Earth emits LESS energy that it receives. Therefore this is not a contravention of the laws of thermodynamics as you assert.
You then say “It is based on the fallacy that if the escape of heating is blocked, then the temperature will continue to rise until a ‘radiative equilibrium’ is reached . . ”
If a proportion of escaping IR is radiated back down to Earth then temperatures must increase. As this happens, then more energy is radiated from the Earth at a flux density that is proportional to the fourth power of the increase in temperature. The idea you suggest where “the heat bursts through the barrier,” although meant to be a derisive dismisal of the GHG mechanism, actually misunderstands the issue. It is a simple application of the Stefan-Boltzman equation for blackbody radiation that gives an increase in radiative emissions from Earth, until it once again equals the radiation coming into the Earth.
Your final remark “If it were true we could generate huge amounts of energy from a small input simply by placing an infra-red barrier around a radiator – just tap some of the heat off at regular intervals – free energy,” is completely false. There is nothing about a mechanism that radiates energy back to the Earth and resulting in a temperature increase, that lends itself to the notion that this can in any way lead to free energy. If you try to drain energy from the atmosphere all that would happen is the atmosphere would cool down and the Earth would radiate faster and cool down more quickly. I suggest the same thing will happen with your ‘infra-red barrier around a radiator.’

Bryan
March 1, 2011 2:31 pm

George E. Smith
Did the classical EM radiation laws of Maxwell not run up against the ultraviolet catastrophe and hence the modification by Panck and Einstein introducing the quantised photon?
I have always understood that continuous spectra are associated with radiating solids.
For gases that radiate a line spectra is what I’d expect.
You can flick between absorption and emission spectra for H2O
http://webbook.nist.gov/cgi/cbook.cgi?ID=C7732185&Units=SI&Type=IR-SPEC&Index=1#IR-SPEC
Same also for CO2
http://webbook.nist.gov/cgi/cbook.cgi?ID=C124389&Units=SI&Type=IR-SPEC&Index=1#IR-SPEC

Tim Folkerts
March 1, 2011 2:38 pm

kbray in california says: March 1, 2011 at 1:23 pm
How about this…..
1) Chill 1 bottle of distilled water and 1 bottle of CO2 injected mineral water …

One problems with this experiment is that it is missing “outer space”. CO2 (or H2O) limits the ability of the IR to “escape” from a warm area (the earth) to a cool area (the rest of space). Without the cold surroundings, you really can’t model the “greenhouse effect”.
You really need:
1) a warm object (perhaps with a light shinning onto it)
2) a cold enclosure around the object (so that the net IR flux will flow from the object to the enclosure). Perhaps a deep freeze.
3) controllable atmosphere (CO2, humid air, dry air etc) between the two that is significantly warmer than the walls of the enclosure.
If the greenhouse effect is true, CO2 or H2O would be radiating IR back to the object. The object will cool more slowly (controlling of course for conduction & convection).
Even this will be tough to see because it takes many meters of CO2 to absorb/emit much IR.
(hmmm … as a side thought, does anyone know just how far IR of various wavelengths would penetrate thru CO2? Eg how far it takes to attenuate 50% or 99% the intensity of the IR light? For 400 ppm it clearly takes less than the height of the atmosphere, but how much less?)

RJ
March 1, 2011 2:39 pm

Vince
I still can not see how a small amount of CO2 can heat a much larger warmer earth. Its a bit like a very small heater heating a massive room for one. And secondly I do not accept that a colder body can heat a warmer one.
If a person was enclosed in a container of CO2 would their temperature rise due to the greenhouse effect. Or would the CO2 just slightly reduce the rate of cooling. I would say it would only reduce the rate of cooling. Is this correct or not a very good example as a comparison.

Richard Smith
March 1, 2011 3:18 pm

Vince Causey said in response to my comment:
“Surely, if temperatures are rising, (as posited by the GHG hypothesis) it must mean the exact opposite – namely that the Earth emits LESS energy that it receives. Therefore this is not a contravention of the laws of thermodynamics as you assert.”
No. Look at the Kiehl and Trenberth global energy flows diagram, for example. Earth receives 64wm2 (after deduction of thermals and evapotranspiration from insolation of 161 wm2) which somehow backradiation magnifies to an emission of 396wm2. This is more energy out than in.
Vince then says:
“There is nothing about a mechanism that radiates energy back to the Earth and resulting in a temperature increase that lends itself to the notion that this can in any way lead to free energy. If you try to drain energy from the atmosphere all that would happen is the atmosphere would cool down and the Earth would radiate faster and cool down more quickly. I suggest the same thing will happen with your ‘infra-red barrier around a radiator.’”
Well according to the radiation equilibrium theory, I could get a huge amount of energy with an infra-red barrier. But if that example does not impress you, how about a furnace with an infra-red barrier. A much cheaper way of melting steel. Why is it that nobody has patented this yet?

kbray in california
March 1, 2011 3:27 pm

[[[ Tim Folkerts says:
March 1, 2011 at 2:38 pm
kbray in california says: March 1, 2011 at 1:23 pm ]]]
Tim,
Have you ever put a sheet or glass in front of an Infra Red heater ? The IR goes right through the glass. The heat will escape through the glass. And the cold? The room is purposely kept colder in the experiment to simulate the colder surroundings of outer space.
Increased heat should still show up in the mineral water bottle if CO2 has that ability.
Your model is unlikely to create any meaningful data, it has too many variables and just the staging of your experiment sounds impossible… besides, I am only testing CO2 not the whole shabang. I go by KISS – keep it simple son.

Myrrh
March 1, 2011 3:29 pm

Tim Folkerts says:
March 1, 2011 at 5:55 am
Myrrh says: March 1, 2011 at 2:45 am
“Ira says that Visible is the largest part of the Sun’s spectrum, wrong, it’s actually the smallest, and compared with the others, very very small. Light is not hot, it is Reflective not Absorptive, and your use of “absorbed by matter of one form or the other” is misleading. The radiation that penetrates to heat the Earth is Thermal IR. And that is not in the Chart.”
The issue here is the “size of the energy”, not the wavelength. There is a handy table at http://en.wikipedia.org/wiki/Planck%27s_law that shows the energy distribution of sunlight (above the atmosphere).
* A little over 10% of the ENERGY is in ultraviolet photons or shorter wavelengths.
*Close to 40% of the ENERGY is visible light photons
*Over 40% is “near IR” (from 0.7-3um). (So Ira’s claim that visible is the biggest is not quite right, but it is not far off. On the other hand, the atmosphere is still mostly transparent to these wavelenghts, so his arguments still hold).
*Only a few % is above 3 um (“thermal IR”) so it cannot possibly be the main source for heating the earth.

It doesn’t show any such thing, missing bits. See http://ds9ssl.berkeley.edu/lws_gems/e/espec.htm
I think I’m going to start calling this AGWplanks law since its use has resulted in that Chart which made incoming Thermal IR from the Sun walk the plank out of our physical Earth and it’s now become practically impossible to find anything rational about this subject. Visible light is a tiny sliver of the electromagnetic spectrum, as you can see from the above link, it may be highly energetic, but it’s not the highest of that either.
Planck’s law “In physics, Planck’s law describes the spectral radiance of electromagnetic radiation at all wavelengths from a black body at temperature T. As a function of frequency v, Planck’s law is written as: …….Note also that the two functions have different units – the first is radiance per unit frequency interval while the second is radiance per unit wavelength interval.” http:www.worldlingo.com/ma/enwiki/en/Planck’s_law
All Planck’s law shows as graphs depict is that the hotter an object the higher the peak in Visible light. How does the Radiance peak here mean it has a greater AMOUNT of the ENERGY of that produced by a heated body?
That’s how steel workers can tell the temperature of steel they’re working on, from the degree of radiance as it goes into colour. It doesn’t mean anything else. It takes very hot to produce white light. The Sun’s heat certainly hot enough to produce white light.., but it’s a peak of radiance into Visible, it hasn’t stopped producing Thermal Infrared, nor has it stopped producing any of the other wavelengths which you haven’t included.
http://m.plantengineering.com/index.php?id=2831&tx_ttnews%5Btt_news%5D=33209&cHash=db4db9479b
“Not as widely recognized is the fact that incandescent objects emit a tremendous amount of invisible infrared radiation. For example, the radiance of a steel billet at 1500F is 100,000 times greater in the infrared spectrum than in the visible spectrum.”
The real “peak amount” then between the Visible and Thermal IR is not in the Visible. Planck’s peak frequency into visible does not equal peak amount given off by a heated object.
A bog standard lightbulb gives 95% of its energy in Heat, which is Thermal Infrared (Near Infrared included in “Solar”, is not hot, it’s a cold light.) If you drew a graph showing this relationship, where would the peak be?
……………………………………..
izen says:
March 1, 2011 at 6:45 am
Re: the same quote of mine, above.
The vast majority of the energy direct from the Sun that heats the Earth is in the visible spectrum, NOT the IR. If you doubt that visible light can heat things consider the car on a sunny day. The glass of the windows blocks IR but lets through visible light that is absorbed by the (usually) dark plastic/leather interior. The hot steering wheel and seat are warmed by the visible light not any IR.
Glass does not block IR. Visible light is REFLECTIVE. It bounces off things. IR is ABSORPTIVE in organic stuff, the car is absorbing IR Heat all over.
You are correct of course that the surface is ALSO heated by the 7um and 15um IR emissions from the H2O and CO2 in the atmosphere that has been warmed by the IR emissions from the surface..
Well you have to say that don’t you, because you’re following AGWScience which can make up any number of impossible things for you to believe before breakfast. The heat we feel from the Sun, DIRECTLY, is Thermal IR. Regardless of whatever else amount is coming to us, from the heated things around us for example, to exclude this direct Thermal IR from the Sun is just plain ludicrous. I’m finding it impossible to phrase it any other way.
…………………………………………..
Ira Glickstein, PhD says:
March 1, 2011 at 6:11 am

Re: Myrrh says: I’m really at a loss to understand any of this. How on earth does Visible light and near short wave heat the Earth?
Myrrh, you really need to get outside more and sit in the Sunshine and feel the warmth! That is how visible and near-visible (“shortwave”) light warms the Earth.
If you don’t or cannot get outside, turn on an old-fashioned incandescent light bulb and hold your hand near it (not too close you will get burned). Feel the heat? That is shortwave light because the filament is heated to temperatures similar to the Sun’s surface. You can tell it is shortwave because you can see the light.

Well, again with the intellectual disdain from the so-calling themselves experts..
Ira, please take note of my replies above. I am determined to get to the bottom of this because this is a KEY premise on which AGW energy is based and all other energy arguments depend, and it’s simply nonsense.
For lightbulb information – http://www.newton.dep.anl.gov/askasci/eng99/eng99505.htm
& especially:
Physics 101: http://science.hq.nasa.gov/kids/imagers/ems/infrared.html
Infrared light lies between the visible and microwave portions of the electromagentic spectrum. …The longer, far infrared wavelengths are about the size of a pin head and the shorter, near infrared ones are the size of cells, or are microscopic.
Far infrared waves are thermal. In other words, we experience this type of infrared radiation every day in the form of heat! The heat that we feel from sunlight, a fire, a radiator or a warm sidewalk is infrared. The temperature-sensitive nerve endings in our skin can detect the difference between inside body temperature and outside skin temperature.
Shorter, near infrared waves are not hot at all – in fact you canot even feel them. These shorter wavelengths are the ones used by your TV’s remote control.”
So, WE CANNOT FEEL VISIBLE LIGHT – it is not hot. It does not carry HEAT. The Radiation we feel from the direct from the Sun which is HOT, is Thermal IR.
You have excluded this in your Chart. We can all feel you’re wrong to do so..
This AGW premise defies REAL Science, it is already FALSIFIED. Nothing that AGW calculates thereafter from this premise has any credibility whatsoever.
Has it?
Now, as I said, I’m finding it really difficult to find anything discussing this sensibly at all, most of what’s on line has been so thoroughly trashed by AGWScience propaganda in its utter mangling of basic science concepts. Here it is attributing to Visible light and near neighbours (Solar of AGW), that which is rightly only applicable to Thermal IR.
But, I did find this just now: http://ishangobones.com/?p=509
Which appears to be explaining the actual process I’ve been thinking of as Reflective v Absorptive.
Thermal IR’s absorption method I’ve seen described as Conversion in those areas which deal with its absorptive energies, capacities, spectroscopy, medical and such, (as in a heat pad delivering Thermal IR to aching muscles, etc.), but I wasn’t concentrating on it, and I seem to recall a description similar to what’s being said here. Encyclopedia of planetary sciences says “Absorption is the conversion of electromagnetic energy to another form of energy through interaction with matter. The process can be viewed at several levels, but the end result is usually heat.”
Anyway, Thermal IR is absorptive and Visible and Near IR are not, but are reflective in all general descriptions of the difference.

wayne
March 1, 2011 3:43 pm

Al Tekhasski says:
March 1, 2011 at 12:01 am
I am sorry, but for the sake of accuracy, CO2 in air does not have any states that interact with 10-13um band. Therefore, hot air cannot possibly generate any photons in that range. Therefore the following statement is also wrong, nothing gets “transferred” into 10-um band from “heated air”:
—-
So you are saying that if you had a large clump of warm nitrogen in empty space held together by gravity that it could not radiate in a black body manner at all, zero, none, zip? Maybe check some good astronomy books on that matter that cover quantum aspects.
Its radiation as a black body would be much lower (low emissivity at a frequency) than the few large emissivity emission lines in N2’s spectrum but the much smaller BB radiation would still be there per the temperature. And you cannot have a temperature without there being many, many molecules or atoms (LTE). All matter (not a single isolated molecule) radiates in a black body manner except at zero K. Now if you are talking of one isolated warm N2 molecule moving isolated in empty space you would be correct, it could not radiate except at it’s emission lines and once it reached it’s ground electron, vibration and rotational state it could not radiate at all, zero, zip, none. It is the collisions and interactions between multiple molecules (between the electrons really) that create the much smaller BB background radiation. That is how I see it from my years in studying physics.
Do you see, Ira placed no numbers on exactly how much was split between those 7, 10, and 15 µm band portions. Just that those interactions do occur.
The same is for CO2 molecules or any atoms or molecules when not in isolation (much like in the solar wind of particles or inter-galactic gases).
If you have some good books or references countering this please leave them in a comment before leaving.

Dave Springer
March 1, 2011 3:51 pm

George E. Smith says:
March 1, 2011 at 2:08 pm
Thanks for the further explanation between cold/hot and thick/thin gases. The Rutgers statement of Kirchoff’s First Law of Radiation was not clear about the distinction and I thought further clarification would probably be needed.
Cold dense gases emit a continuous blackbody spectrum characteristic of their temperature. “Cold” means below the ionization energy threshold. “Thin” is a little more ambiguous but your description was good i.e. thin enough so that collisions are rare. In the earth’s atmosphere “thin” would begin beyond the mesopause at 90 kilometers where the temperature starts increasing with altitude and can rise to thousands of degrees F.

Dave Springer
March 1, 2011 3:54 pm

CO2 IS INSULATION.
IT DOES NOT HEAT ANYTHING. IT SLOWS DOWN HOW FAST THE SURFACE COOLS.
I WONDER IF ALL CAPS WILL HELP. GOD KNOWS I’VE TRIED EVERYTHING ELSE TO GET THIS SIMPLE CONCEPT ACROSS.

Dave Springer
March 1, 2011 4:06 pm

Tim Folkerts says:
March 1, 2011 at 2:38 pm
“For 400 ppm it clearly takes less than the height of the atmosphere, but how much less?”
APPROXIMATELY 12,000 FEET OVER THE ARCTIC OCEAN. SEE THE GRAPH OF IR SPECTRUM FROM 20,000 FEET LOOKING DOWN THAT IRA POSTED IN THE COMMENTS TODAY.
IN THE IR WINDOW YOU SEE A 265K BLACKBODY CURVE. IN THE 15UM CO2 ABSORPTION WINDOW YOU SEE A 225K BLACKBODY CURVE. THIS IS A TEMPERATURE DROP OF 40K. DRY ADIABATIC LAPSE RATE IS 1K PER 100 METERS SO THE POINT WHERE THE SPECTROMETER NO LONGER INDICATES ANY 15UM ABSORPTION IS 4000 METERS.
THIS WILL VARY SOMEWHAT DEPENDING ON THE TEMPERATURE AND ALTITUDE OF THE SURFACE. AT HIGHER SURFACE ALTITUDES THERE IS LESS TOTAL CO2 IN THE COLUMN ABOVE IT AND IT WILL TAKE MORE THAN 12,000 FEET OF AIR TO GIT ‘ER DONE. THE TEMPERATURE OF THE SURFACE WILL SHIFT THE PEAK SURFACE EMISSION FREQUENCY AWAY OR TOWARDS 15UM WHICH MEANS LESS OR MORE, RESPECTIVELY, 15UM ENERGY TO ABSORB.

March 1, 2011 4:16 pm

Dave Springer;
ALL CAPS – LOL
Richard Smith;
You enjoy having your rants cut to shreds in one thread after another? Well at leat you’ve finally given in on the igloo… now if we can just get you past trying to define absorption and re-mission in a random direction as inventing perpetual motion…

Dave Springer
March 1, 2011 4:18 pm

Al Tekhasski says:
March 1, 2011 at 12:01 am
“I am sorry, but for the sake of accuracy, CO2 in air does not have any states that interact with 10-13um band. Therefore, hot air cannot possibly generate any photons in that range. Therefore the following statement is also wrong, nothing gets “transferred” into 10-um band from “heated air”:”
I AM SORRY BUT YOU ARE WRONG. COLD DENSE GASSES ALL EMIT A CONTINUOUS BLACKBODY SPECTRUM. SEE KIRCHOFF’S FIRST LAW OF RADIATION WHICH I POSTED EARLIER.

robr
March 1, 2011 4:29 pm

Ira Glickstein, PhD says
I have two statements/observations with respect to this radiation:
1.) Forget thermo for a moment and let’s talk heat transfer. Two infinite planes separated by a distance in equilibrium (the earth being one and some height in the atmosphere being the other) – the radiosity of the one equals the emissivity of the other. The radiative heat transfer from the warmer to the colder is in proportion to the fourth power of the temperature difference. So the CO2 issue would necessarily raise the atmosphere temp, but where the temp difference between the earth and atmosphere is small, the difference between the atmosphere and space is large, so the fourth power factor of the temp would greatly lessen any lasting heating.
2.) All this back scattering and stuff only works when the light is on. It is like shining a light in a mirror lined room, it bounces around good, but turn off the light and nothing. Once the sun goes down the only heat retained in the atmosphere is the latent heat of water vapor, all that radiation goes poof into space. Take the water vapor out of the air and I don’t care how much CO2 you have in the air, when night comes it is going to get real cold.

March 1, 2011 4:34 pm

There were a number of comments in the thread asking questions about, or proposing various lab experiments with cylinders of artificial atmosphere, or other approaches. They are invalid.
They just don’t scale to reality and the reasons are well known. Even putting aside the existance of other kinds of molecules in the atmosphere, the cylinder in the lab with CO2 in it isn’t even close. For starters, it is at pretty much the same temperature from one end to the other. In the atmosphere, temperature declines with altitude. So the frequency range of photons that can be absorbed or emitted changes with altitude. And time of day. And latitude. And season.
PLUS, the pressure in the lab cylinder is stable. In the atmosphere, pressure declines with altitude, so while the CO2 concentration may be stable in terms of parts per million, in terms of molecules per cubic meter, it declines.
If that hasn’t completely discredited the lab cylinder experiment yet, let me continue by adding JUST water vapour to the picture. If we were to add H2O molecules to the equation, unlike CO2 which is evenly distributed throughout the atmosphere, the H2O molecules would be clustered at the bottom of the atmosphere near earth surface. In the real world, the holding capacity of the air declines with temperature, so the water vapour concentration may be as high as 40,000 ppm or less than 1,000 depending on temperature. And temperature varies with…altitude, time of day, latitude, and season. So down at earth surface 40,000 H20 vs 390 CO2, there’s not much point even doing the math to calculate the effect from CO2, it is meaningless. But as we move in altitude, latitude, season and so on to cooler temperatures and lower levels of water vapour, CO2 becomes more and more significant.
Sorry, not done yet. What else goes on in the atmosphere? Convection! As air is heated at the equator, it rises, pulling in cooler air from the temperate zones. As the hot air rises, it cools. How? By on average emitting more photons than it is absorbing. And as it cools, the wavelength of photons that is released changes… the percentage chance that an emitted photon from a rising molecule of CO2 will escape increases as the molecule gains altitude because the path to space is shorter. And the cooler air being sucked down from the poles is doing the opposite.
Then consider all of THOSE factors in terms of what wavelength of photons are being release and what wave length are being absorbed at any given point in time based on all of those factors and map that against the atmospheric window….
Just like Ira’s physical model or the explanation of the atmopsheric window in this article, a lab experiment simplified down to a cylinder with air in it is fine for evaluating certain aspects of CO2 and IR, but for drawing any conclusions about the climate? Inadequate.

Myrrh
March 1, 2011 4:44 pm

As it “re-radiates” in all directions, then it also must be said that it speeds up how fast the surface cools. Right?

George E. Smith
March 1, 2011 4:56 pm

“”””” Bryan says:
March 1, 2011 at 2:31 pm
George E. Smith
Did the classical EM radiation laws of Maxwell not run up against the ultraviolet catastrophe and hence the modification by Panck and Einstein introducing the quantised photon?
I have always understood that continuous spectra are associated with radiating solids.
For gases that radiate a line spectra is what I’d expect. “””””
So I take it you are implying that the near Black Body radiation Spectrum from a radiating solid, is NOT a continuous spectrum; whiel also saying that it is.
Was it not the introduction of quantization that led from the “ultraviolet catastrophe” that is quite unrelated to Maxwell’s equations for electromagnetic radiation to the highly successful BB radiation formula of Planck.
If you reread your history, you will find, that what was quantized to turn the unsuccessful Raleigh Jeans formula into the successful Planck formula was not the quantization of radiant energy levels but of the average energy per degree of freedom of vibrating molecules due to their Temperature.
The Jeans derivation assumed that the energy per degree of freedom (three for a translating only body) could have any continuous value. Planck’s breakthrough came in requiring the energy per degree of freedom to be quantized. The radiated frequencies are not quantized, and depend only on the Temperature.
Remember that the theory of black body radiation is a purely hypothetical one since no such object actually exists; and as a consequence it is connected in no way to the actual physical properties of any material; just the Temperature; so it cannot possibly be related to any energy level structure, all of which are properties of real materials.
And Planck’s derivation takes no account of the actual phase of the material doing the radiating; just its Temperature.
(atomic )Gases emit both line spectra; that are a consequence of the electron structure of those atoms; but when ionised, they can also emit a continuum radiation that is in the Ultra-Violet beyond the infinity end of the series like Balmer series and others; and they are a continuum, since the electron that is captured by the ion to radiate the photon energy, can have any energy at all while it is a free electron, so the energy differnece of the transition from a free electron to a bound state can have any value. such atomic continuum spectra are observed in the spectra of many stars.
The BB radiation spectrum arises not from discrete energy levels of any atoms or molecules, but from the acceleration of the electrons of the atoms or molecules as a result of Molecular collisions, ie Temperature.
Einstein’s quantisation of photon energies, came about as a result of his work on the Photo-electric effect, which is what he got his Nobel Physics Prize for.
Classical theory calculated the energy density of the EM field from Maxwell’s equations. From that energy density, and the crossection of a photoelectric effect material atom, such as Cesium for example, one could calculate how long it would take to intercept enough energy to release a bound electron from the material. So it was assumed that if one lowered the intensity of the “light”, it would take longer to collect enough energy from the EM field, so delaying the release of the Photo-electron.
Instead, Einstein found that no matter how much the light was attenuated; the emission of the electron was alwqays instantaneous; there was no delay to accumulate enough energy (no delay in the technology of those days). But he also discovered by selecting individual wavelengths, that no matter how bright the illumination might get; some times there was no photo-electron emitted at all. Th3e longer wavelength illuminations failed to release photo-electrons, the shorter wavelength illumination no matter how dim, released electrons instantaneously, and the kinetic energy of those electrons increased for shorter wavelength light.
He reasoned that the light must come in packets each containing a certain energy (E= h.nu), and all that happened when you attenuated the light, was the number of packets was less so you got fewer photo electrons emitted, but the KEs of those emitted were still the same no matter how dim the light. So far as I know to this day nobody has successfully explained the Photo-electric effect in terms of any classical theory of Physics.
But all that did not send Maxwell’s equations to the dustbin of history; it is enshrined forever, in the velocity of light as c = 1/sqrt( mu-naught x Epsilon-naught). Those three fundamental constants are about the only fundamental Physical constants whose values are exact with zero error (by definition).
So Maxwell still reigns supreme; just not over everything, and in particular Maxwell’s equations are not inconsistent with the Planck formula or the Stefan-Boltzmann formula (which is simply the integral of the former.)
One can find excellent treatments of the various Radiation laws, in various Handbooks of Optics such as the one sponsored by the Optical Society of America and edited by Walter G. Driscoll. The section on BB-radiation is authored by Jay F Snell at Tektronix. One can also check “Applied Optics, and Optical Engineering” Vol IV by Rudolph Kingslake (Eastman Kodak).
Snell incidently cites Kichoff’s law thusly:-
“Kirchoff’s Law is a consequence of the necessary existence of an energy balance between emission qnd absorption for a body in an isothermal black enclosure, and in Temperature equilibrium with the enclosure.”
Such conditions exist nowhere in nature; but we can actually build quite good approximations to such enclosures. Notice it says “black enclosure” meaning black in the black body sense, of total absorption of all radiation incident on the walls of that enclosure. Kirchoff’s law requires a wavelength specific balance. That is the absorption and emission of every single possible wavelength must match; but not it is a condition only of total equilibrium of a closed system.
Earth’s atmosphere is NOT a closed system, and it is never in thermal equilibrium with anything. So Kirchoff’s law simply does not apply; no matter how hard people try to make it so.

kuhnkat
March 1, 2011 5:04 pm

George E. Smith,
“Did the classical EM radiation laws of Maxwell not run up against the ultraviolet catastrophe and hence the modification by Planck and Einstein introducing the quantised photon?”
One of the misconceptions that even good scientists fall prey to is believing that mathematics drive science. Mathematics is a tool that can be used to DESCRIBE the real world and allow us to manipulate ideas about it and make projections if we do a good enough job of the description.
I can draw a picture of something and easily transfer a number of data points to tohers through a picture with absolutely no understanding by wither of us of what we are seeing. Mathematics can do the same for the real world in physics.
Sadly climate science has latched onto a few data points and algorithms and think it covers EVERYTHING while still struggling with how poorly their models do. At a much higher level quantum physicists do the same. It really is all RELATIVE!!
HAHAHAHAHAHAHAHAHAHAHAHA

Bill Illis
March 1, 2011 5:13 pm

Here is the outgoing longwave radiation map on Feb 20, 2011 from the CERES satellite.
Can you see the continents? Can you pick out the oceans?
Well, if the emission to space went right through the atmospheric windows, right through the spectra which are not intercepted by the GHGs, one should be able to see the hot parts of the continents, or the cold parts of the continents. Or something.
What the map is really showing is that emission to spaces occurs at various heights in the atmosphere and cloudiness is a very important factor in this and that the atmospheric windows are not really apparent. Maybe this a bit esoteric, but it is telling you what is really happening in the atmosphere. It is not a AGW global warming map. It is reality. [This is always my default position, what really happens versus what the theory says should happen].
http://img132.imageshack.us/img132/1866/renderdata.jpg

wayne
March 1, 2011 5:16 pm

Ira, I mostly praise the way you presented this post, much clearer, but the only thing I will complain about of you post is in this statement:

However, they differ in the mechanism. A real greenhouse primarily restricts heat escape by preventing convection while the “greenhouse effect” heats the Earth because “greenhouse gases”
(GHG) absorb outgoing radiative energy and re-emit some of it back towards Earth.

There you need to lose the statement “heats the Earth”. That is nonsense. You might say “keeps Earth warmer that without” or “slows the cooling of the Earth”, both implying the action of an insulator, but anything but what you said.
For myself, I have now move on the scale from ‘warmist’ to ‘skeptic’ and now just a tad before ‘denier’ so I think both of those statements are also most likely incorrect, but still that’s a better way for you to state it. It’s just that “warms the Earth” breaks core thermodynamic principles and it unqualifiedly wrong. Best to admit it and restate.
But I know you’ve already gotten an earful on that same matter.

George E. Smith
March 1, 2011 5:20 pm

The room temperature (300K) band gap of silicon is 1.106 eV Einstein’s constant is 1.23980 electron Volt microns.
So any photon of shorter wavelength than 1.121 microns, can be absorbed in bulk silicon, and release carriers, to be transported across a PN junction; to create a photocurrent flow. Well that assumes that the carrier lifetime is long enough for them to propagate to the junction and cross it, before they recombine.
So silicon diodes can absorb sunlight shorter that 1.121 microns wavelength, down to at least 400 nm and create a photocurrent in a “solar cell”.
But don’t try to get that same silicon junction to reverse its behavior when you pass a forward current through it, and emit any photons.
Silicon is an indirect gap semiconductor, and the reversal of the absorption transitions are prohibited, so silicon does not form Light Emitting Diodes.
So there’s a simple case of a solid that simply cannot radiate the same photon energies that it can easily absorb. Neither can Germanium which also makes good (low Voltage) solar cells.
But GaAs with its 1.47 eV bandgap readily emits 844 nm photons, which is the bandgap photon energy, because it is a direct gap semiconductor, and that transition is allowed, without any momentum discrepancy, requiring a phonon interraction as well.
So no Kirchoff’s law simply doesn’t apply to very many real world situations.

George E. Smith
March 1, 2011 5:26 pm

“”””” kuhnkat says:
March 1, 2011 at 5:04 pm
George E. Smith,
“Did the classical EM radiation laws of Maxwell not run up against the ultraviolet catastrophe and hence the modification by Planck and Einstein introducing the quantised photon?”
One of the misconceptions that even good scientists fall prey to is believing that mathematics drive science. Mathematics is a tool that can be used to DESCRIBE the real world and allow us to manipulate ideas about it and make projections if we do a good enough job of the description. “””””
I have no idea what your point is; do you have one you’d care to state ?
And there is NO mathematics that can describe the real world or even attempts to. Mathematics can be used to describe the expected behavior of our theoretical modles of the real world; which are every bit as fictional as the mathematics is; we made all of it up, so none of it is real.
We do try to construct our fictional models to try and mimic reality; but that is all they do; they do not explain reality.

March 1, 2011 5:29 pm

Wayne wrote:
“So you are saying that if you had a large clump of warm nitrogen in empty space held together by gravity that it could not radiate in a black body manner at all, zero, none, zip? Maybe check some good astronomy books on that matter that cover quantum aspects.”
and
“Ira placed no numbers on exactly how much was split between those 7, 10, and 15 µm band portions. Just that those interactions do occur.” … That is how I see it from my years in studying physics.”

Wayne, maybe you need to continue study physics for some more years and learn how to put numbers on magnitude of effects. I am sure you heard about “pressure broadening” and “collision-induced absorption” during your studies. Now consider that we are not living on a star. Please open your reference book and compare gas pressures and temperatures of stars with Earth atmosphere.
Then try to comprehend the the difference between numbers. It is called “Physics”.
Please also do understand that “greenhouse effect” does not occur because 1/1,000,000 fraction of 15um band energy gets re-distributed and re-emitted from 10-13um band.
But of course you are formally correct. Instead of saying “hot air cannot possibly generate any photons in that range” I should have said “hot air cannot generate any remotely considerable amount of photons in that range”.

March 1, 2011 5:40 pm

Dave Springer says:
March 1, 2011 at 3:54 pm
CO2 IS INSULATION.
IT DOES NOT HEAT ANYTHING. IT SLOWS DOWN HOW FAST THE SURFACE COOLS.
I WONDER IF ALL CAPS WILL HELP. GOD KNOWS I’VE TRIED EVERYTHING ELSE TO GET THIS SIMPLE CONCEPT ACROSS.
Errr, NOPE, it don’t help, YOUR the one missing the point.
(I hope the capitals help)
Here is a more realistic way to “visualise” the “greenhouse effect” as commonly (and incorrectly) explained and viewed at present.
from,
http://www.globalwarmingskeptics.info/forums/thread-855.html
Could someone please explain to me (understandably) why
a thermal image of a greenhouse shows it radiating more than it’s surroundings. ?
(I know the greenhouse radiates more because it is warmer than it’s surroundings, but
it is supposed to trap radiation, yet (somewhat inconveniently) greenhouses, as far as I’m aware, radiate according to the Planck curve)
I thought a greenhouse was supposed to “trap” radiation.
Is Plancks law wrong, surely not.
So, would the better question be. Why are the greenhouses surroundings so much cooler than the greenhouse, although
the surroundings do not actually “trap” radiation, they do appear to be radiating far less than the greenhouse.. ?
What then is cooling the surroundings. ?
I am assuming the best explanation would be because the surroundings are cooled by something far more powerful than radiation looses,
namely conduction and convection of sensible and latent heat.
A greenhouse “works” because it reduces conduction and convection to it’s surroundings.
It would appear reasonable to say observation of a thermal image of a greenhouse and it’s surroundings indicates that
conduction and convection (of sensible and latent heat) is far more powerful than radiation looses, and
is responsible for cooling the surroundings mostly.
Is this a correct series of assumptions, or rather statements of the blitheringly obvious.
I too am bored with the way “climate discussions” seem to be either circular, or descend into mud slinging.
Maybe, just maybe, present discussions are discussing the wrong “things”..
End of quote.
The above has recently been misquoted on this blog by someone else.
In the end, the REAL QUESTION, that is avoided, is simple.
It is,
Why do physicists using closed, isolated, far higher concentrations than are realistic, to suggest (and supposedly observe that) CO2 has a high specific heat capacity,
YET,
CHEMISTS USING THEIR MASS BALANCED EQUATIONS SHOW CO2 HAS A LOW SPECIFIC HEAT CAPACITY.
(Hey, this caps thing is quite good isn’t it..)
Maybe, just maybe, CO2 reacts differently in an open and mixed system, at far, far, far lower concentrations than a closed, isolated, at far, far, far, far, far, far, higher concentration of CO2 system.
Dam, the EPA never thought of (or understood) that, AND niether did most “climate sceptics” either apparently.
(brackets are quite good as well.)
Increased CO2 in the upper atmosphere increases global cooling , obviously,
BECAUSE,
it increases (the planet’s ability to loose, or rather emit) radiation of energy to space.
AND,
CO2 helps move energy about FASTER in the lower atmosphere,
BECAUSE,
conduction and convection (of energy AND latent heat) is increased,
BECAUSE,
of the physical properties (which “we” really are not sure of) of CO2.
But this is all irrelevant, CO2 is dwarfed into insignificance by H2O and
it’s nefarious abilities, most undeniably including change of state,
which at atmospheric temperatures, CO2 just can not touch.
CO2 AIN’T INSULATION.
It is the staff of life, this planet is almost entirely, carbon based life forms.
(as James T Kirk noted, way back when, when Star Trek was young)
Nowhere near enough people (and almost ALL politicians + bureaucrats ) understand how little “climate science” actually does know.
Lines 2 and 3 of the infamous Rumsfeld quote describe the current state of the “settled science” of AGW and “climate science” best at present, in my opinion.
ie,
“Known, unknowns, and
unknown, unknowns.”

George E. Smith
March 1, 2011 5:40 pm

“”””” Bryan says:
March 1, 2011 at 2:31 pm
George E. Smith
Did the classical EM radiation laws of Maxwell not run up against the ultraviolet catastrophe and hence the modification by Panck and Einstein introducing the quantised photon?
I have always understood that continuous spectra are associated with radiating solids.
For gases that radiate a line spectra is what I’d expect.
You can flick between absorption and emission spectra for H2O
http://webbook.nist.gov/cgi/cbook.cgi?ID=C7732185&Units=SI&Type=IR-SPEC&Index=1#IR-SPEC
Same also for CO2
http://webbook.nist.gov/cgi/cbook.cgi?ID=C124389&Units=SI&Type=IR-SPEC&Index=1#IR-SPEC “””””
So that CO2 infrared spectrum for example, is the absorption spectrum for 390 ppm of CO2 in dry standard air, I take it; or am I presuming too much. You did check that the spectrum is for the system of primary interest; namely earth’s lower tropospheric atmosphere; didn’t you ??
Your spectra look nothing at all, like the spectralcalc ones that Phil has pointed us to; can you explain that ?

George E. Smith
March 1, 2011 5:52 pm

“”””” Myrrh says:
March 1, 2011 at 5:26 pm
http://wiki.answers.com/Q/What_percentage_of_the_electromagnetic_spectrum_is_visible_light
some answers.. “””””
So now we go from the sublime to the ridiculous. That wiki answer to the question it total BS; and you can use your own non wiki dictionary explanation of BS.
The proposed standard Solar spectral irradiance (w/m^2/micron) contains 8.725% of the energy below 400 nm (UV) and 56.023% below 800 nm (visible, so that means 47.3% of the total solar spectrum is visible, and only 44% is in the IR from 0.8 micron to infinity. So there is more visible than IR

March 1, 2011 6:05 pm

Was just thinking I’ve long since lost track of how many physicists, engineers, chemists, scientists of who knows how many stripes with credentials, real world experience, text books, articles and studies galore at their finger tips, having a raging argument about how photons interact with CO2 molecules. Such a tiny simple question about just that.
But the climatologists at the IPCC with thousands of factors to consider, plus all the combinations of those factors… they’ve got a consensus. Wow, they must be really smart 😉

March 1, 2011 6:19 pm

Dave Springer shouted: “I AM SORRY BUT YOU ARE WRONG. COLD DENSE GASSES ALL EMIT A CONTINUOUS BLACKBODY SPECTRUM. SEE KIRCHOFF’S FIRST LAW OF RADIATION WHICH I POSTED EARLIER.”
You should be sorry, because you didn’t get the meaning of “dense gas” as it is used in astronomy and web articles about “continuous spectrum”. When astronomy talks about “dense gas”, they mean “optically non-transparent gas”, like star’s atmosphere or some other non-transparent object. Earth atmosphere is not optically dense, not in the 10-13um band at least. In climatology-speak it is called “IR transparency window”, for that very reason. As such, air does not absorb 10-13um EM waves, and does not emit any “remotely considerable amount of radiation” in that band, at least for any practical reasons.

Phil.
March 1, 2011 6:37 pm

Domenic says:
March 1, 2011 at 11:43 am
to Phil and Cal
Nope. The full characteristics of N2 and O2 in the long wavelength IR have never been actually tested.

Indeed they have, as shown above they are exceptionally weak, it would require incredibly dry air to make the measurement since the spectrum of water is millions of times stronger. Probably very long path length FTIR spectroscopy.
There is something very fishy in the spectral graphs bandied about from calculations regarding the emittance and reflectance of N2 and O2. They are not metals.
Indeed they are not, perhaps you should realize that gases have very well known molecular structures and correspondingly well known spectra.
Both N2 and O2 must be tested thoroughly in the long wavelengths and not guessed at.
No one’s guessing at them, except perhaps you.

March 1, 2011 6:45 pm

Bill Illis submitted a CERES OLR image
http://img132.imageshack.us/img132/1866/renderdata.jpg
and stated:
“one should be able to see the hot parts of the continents, or the cold parts of the continents. Or something.”
Where did you get this picture? Is it possible that the signal was filtered to show absorption CO2 bands only, and not 10-13um? Could it be possible that ground emission in “atmospheric transparency window” is spotty and does not resemble land, so it is hard to recognize? Please keep in mind that 70% of surface are clouds that are blackbodies in IR, so it will not improve visibility either.

Phil.
March 1, 2011 6:59 pm

Theo Goodwin says:
February 28, 2011 at 7:51 pm
bubbagyro writes:
“CO2 is generated on the earth’s surface. It becomes more dilute as it diffuses upward. The models, similar to Ira’s, assume it is a narrow band. This is not true. The very dilute CO2 and water even in the stratosphere absorb radiation. The higher that occurs, the more is lost to space.”
Please expand on this. My understanding is that the modelers assume that concentrations of CO2 are the same wherever they occur in the atmosphere – all the way up. In addition, they assume that the behavior of CO2 molecules regarding radiation is the same throughout the atmosphere. It has always seemed to me that these “uniformity” assumptions were just evidence of an unwillingness to do the necessary empirical research. In plain and simple terms, I would like someone to address the linked questions of “where are the CO2 concentrations and how does radiative behavior change depending on where they are?”

Your assumption is not correct, concentration is not constant, mole fraction is to a good approximation. They do not assume that the radiative properties are the same through the atmosphere, line broadening changes with pressure and temperature.

GaryP
March 1, 2011 6:59 pm

Very good article (and graphics). Most lay people have no idea that CO2 absorbs only a small fraction of the IR spectrum. Those of us who took undergraduate organic chemistry remember the use of IR absorption analysis and the fact that CO bonds absorb only certain wavelengths.
Slightly OT, but VUK said:
There is also possibility of a half way house:
Solar input is constant,
I don’t think that is assumption is a half-way house, I think that position is full on nut house. We have been studying solar output for such a short time, that making any statements about solar output being constant is, IMHO, ridiculous. Based on observations of many other stars, variable output of stars is certainly well known. Our star may be relatively constant in output, or may be in a relatively constant phase. But assuming that solar output is constant over thousands of years is a pretty big assumption that is based on nothing (once again, IMHO) other than wishful thinking.
Certainly, with no convincing explanation for the major climate variations we know have occurred over 10K to multi-M year periods, I would be very hesitant to assume that changes in solar output could not be a contributor.
We should study all aspects of climate, including the most important source of energy into our world climate system (the only other being radioactive decay heat, I believe) a little longer before we make simplifying assumptions that lead us to stupid answers (such as CO2 is the only thing that affects world climate–which is effectively what the IPCC and green lobby asserts today regardless of how much they weasel word it if pressed.)

Phil.
March 1, 2011 7:55 pm

mkelly says:
March 1, 2011 at 12:24 pm
Phil. says:
March 1, 2011 at 10:15 am
“As stated above absolutely wrong, the only way that N2 and O2 molecules can shed energy is by collisional exchange with CO2, H2O etc. molecules which can then radiate.”
Thanks for the information Phil. Your photo while nice does not answer the question of N2 and O2 at the same temperature. Since temperature drives the emittion frequency will they both be the same? I math (Weins Law) says yes, but I have found no info on the subject.

No, why do you think that the N2 and O2 spectra shown are at different temperature?
For two different gases the emission will depend on the transition concerned BB only provides the potential maximum, the line strength will have the dominant effect.
By the way by your statement above you are in the camp that says without GHG we would be a very hot world indeed. Not at -18 C. Once a N2 or O2 molecule was heated via conduction with the ground it would stay heated for a very long time with no H2O or CO2 to reduce its energy. Correct?
No, how do you propose that the atmosphere gets hotter than the surface?

Oliver Ramsay
March 1, 2011 8:02 pm

Derek says:
March 1, 2011 at 5:40 pm
“Could someone please explain to me (understandably) why
a thermal image of a greenhouse shows it radiating more than it’s surroundings. ?
(I know the greenhouse radiates more because it is warmer than it’s surroundings, but
it is supposed to trap radiation, yet (somewhat inconveniently) greenhouses, as far as I’m aware, radiate according to the Planck curve)
I thought a greenhouse was supposed to “trap” radiation.
Is Plancks law wrong, surely not.”
——————————–
You didn’t show your thermal image, but, if it’s showing the greenhouse hotter than the tree adjacent, it’s because the greenhouse is hotter.
If the greenhouse skin is polyethylene, the interior of the greenhoue will be what is seen for the greater part. If it’s glass, it will be the glass that is emitting.
On a clear day, the greenhouse will not be much hotter than adjacent objects with similar exposure to the sunshine. It will be hotter than the air outside. The other objects would be as warm but some heat was convected away.
On a clear night, it will be hotter than adjacent objects and hotter than the air. Once again, it’s about the heat loss on the outside, not heat gain on the inside.
I have just taken readings with an IR thermometer from the outside of my greenhouse, looking in. It is nighttime There is a broken pane that is covered with polyE. The wall of an adjacent shed is 0C. The single-glazed pane of glass shows 7C, the poly shows 15C and through the open window, it shows 16.5C.
Obviously, that only speaks to IR transmission of the materials, since the inside temperature arises from thermal mass or internal heat source.
In practice, a poly greenhouse works about as well as a glass one, in spite of the difference in IR transmission. Conduction/convection cools much faster than radiation in these circumstances. And in many others!
That’s my version!

Jim D
March 1, 2011 8:11 pm

Bill Illis, that satellite picture looks like a water vapor channel. It is not total OLR, nor is it a window wavelength. It is very easy to see the surface diurnal cycle when you don’t look at the water vapor channel. The WV channel has other uses, but not to see the surface. Find other IR images. Typical ones are reversed so that clouds appear white (cold) and the day-time surface is black (hot), going grey at night.
I reiterate, the atmosphere has no way to emit in the 10-micron window region. Its molecules are incapable of producing such wavelengths.

wayne
March 1, 2011 8:21 pm

Al Tekhasski says:
March 1, 2011 at 5:29 pm
[snip the ad hominem]
But of course you are formally correct. Instead of saying “hot air cannot possibly generate any photons in that range” I should have said “hot air cannot generate any remotely considerable amount of photons in that range”.
—–
Better. And no, I don’t have the numbers or even a rough estimate. Also I was not speaking of stars or star’s atmosphere but instead warm IR emitting gas clouds so you never see these in visual measurements or photographs. But, you can look at all of the spectrums of Earth’s atmosphere and see the imprint of the overall black, or better gray, body absorption and/or transmission low at the bottom.
Do you have the numbers instead of pulling 1/1,000,000th from the top of your mind? Many here would like to have such knowledge, or do you prefer it to stay hidden?

Richard Sharpe
March 1, 2011 8:23 pm

Alan McIntire says on March 1, 2011 at 6:40 am

In reply to Katherine and to Phil’s dad. When the Earth’s temperature increases
from 1 to 1 + p, the total radiation increases by a factor of (1 + p) ^4,
Outgoing radiation increase at all wavelengths, but the PERCENTAGE increase at
short wavelengths, which are not affected by CO2, increases at a much larger rate.

Hmmm, so outgoing radiation at all wavelengths increases as temperature, but since the peak goes to lower wavelengths, it just does not increase as quickly at long wavelengths?

So if CO2 results in 40 watts/500 total watts, with a 1% increase in the total to
505 watts, CO2 will absorb less than 40.4 watts. There’s a negative feedback due to that 4th power increase in radiation with respect to temperature, as you discovered, there’s also a negative feedback with respect to CO2 due to a larger percentage of increased outgoing radiation in wavelengths not affected by CO2.

Umm, if outgoing radiation increases at all wavelengths, how can that be a negative feedback? It seems that the amount of extra outgoing radiation decreases with each temp increase, so it is logarithmic or something.
In any case, since the CO2 absorption bands are saturated, does it matter if CO2 increases. Also, does pressure broadening depend on partial pressure or total atmospheric pressure?

Tim Folkerts
March 1, 2011 10:34 pm

Dave says
“Enough already with the argument that certain gases that don’t absorb infrared can’t emit it…. The kinetic energy gained by the nitrogen molecules will be lost in a continuous blackbody spectrum characteristic of the temperature of the gas.”
OK, enough with theory and arguments! Let’s study the data that you touted — the data looking up at downward IR. You postulate a continuous BB spectrum from the N2 & O2 in the atmosphere. Where is that BB radiation in the data?
Looking up into the sky, it is clear that SOMETHING is emitting close to a BB radiation curve @ ~265 K (the atmospheric temperature near the surface), but only above ~14 um or below ~ 8 um (which happens to be where H2o & CO2 emit well). That radiation we can attribute to GHGs near the surface.
Between 8-14 um, the energy is typically around 5% of the BB radiation levels that would be expected for ~265 K atmosphere. EVEN IF we attribute ALL that radiation between 8-14 um to N2 & O2, the much more common N2 & O2 molecules are emitting much less energy. At best, they are very poor radiators.
No theory. No Kirchoff’s Laws. No models. Just data.
I don’t know, but I suspect, that even the radiation between 8-14 um is not due primarily to N2 or O2, but rather to GHGs (possibly CO2 or H20, but potentially also O3, CH4 …). That would make the downward contribution from N2 & O2 molecules as even less. So that would make them very very poor radiators.

March 1, 2011 11:10 pm

Wayne remarks snidely: “Do you have the numbers instead of pulling 1/1,000,000th from the top of your mind? Many here would like to have such knowledge, or do you prefer it to stay hidden?”
Glad to oblige. The number of six orders of magnitude can be seen from this picture, courtesy of “Phyl.:
http://i302.photobucket.com/albums/nn107/Sprintstar400/CO2N2O2.png
– intensity of lines in 10um area are about six orders of magnitude smaller than 15um band.

Richard E Smith
March 1, 2011 11:45 pm

davidmhoffer said:
“Richard Smith;
You enjoy having your rants cut to shreds in one thread after another? Well at leat you’ve finally given in on the igloo… now if we can just get you past trying to define absorption and re-mission in a random direction as inventing perpetual motion…”
David – you are referring to a different Richard Smith who was ‘ranting’ on WUWT a few days ago. It is a case of mistaken identity. I deprecate any ranting from either side. I have now re-registered as Richard E Smith to avoid confusion.

Don V
March 2, 2011 12:09 am

P. van der Meer, Al Tekhasski, Phil – you all get it! I completely concur with your clear thinking.
I’m sorry Ira, but someone has convinced you to believe in a concept that violates the basic laws of thermodynamics. Unless you can convince me that this model does not violate both the first and second law of thermodynamics, I will have to conclude that you have drunk some of the kool-aid. I am not trying to insult you, I respect you, and would like to convince you of the truth, but to do that you will have to get back to the basics, and admit this is just plain wrong!
There is so much wrong I would have to spend an inordinate amount of time writing, so I will focus on just one aspect of it. Your animated illustration at the far right shows the atmosphere absorbing energy radiated up from the earth at 15μ . Think about this carefully now. To do this which body has to be hotter? Earth right? OK so how can the atmosphere with only 15μ radiant energy warm up so hot that it exceeds the earths temperature and radiates back at two wavelengths 7μ and 10μ!? It can’t! The only way you can create a black body radiator at 7μ or at 10μ is to heat a body up to the hotter temp that corresponds to that wavelength. IF it radiates at any black body energy at all, to obey the first law of thermodynamics, it MUST radiate at energy equal to or longer than 15μ. So your illustration and explanation violate both the first and second law since 1) to be true it illustrates that energy in the atmosphere must have been created from nothing, and 2) it illustrates that a cooler body is capable heating up a warmer body.
If I am wrong on this one point then please correct me, and teach me how this can be true. If not admit the mistake and correct the illustration. Then we can go on and correct the other things that are wrong with this “Trenberth” like illustration. While you are at it correct the mistake that shows 10μ radiation from a gas that is not even capable of producing this wavelength as well!

March 2, 2011 1:24 am

mkelly asks:
What difference is there between the spectrum of N2 and O2 both at the exact same temperature and radiating? I have not found anything on that.
The HITRAN (high-resolution transmission molecular absorption) database contains the spectra of all the important gases that absorb in the infrared. Some of the N2 and O2 isotropologues (those with 2 different isotopes) do have measurable spectra in that range, but the 2 most common isotropologues don’t. This has been measured in the lab. Neither molecule has been observed to absorb or emit radiation at the frequencies associated with the temperatures of interest. However, if either molecule gets hot enough, it will emit visible light.
Latter, mkelly continues:
By the way by your statement above you are in the camp that says without GHG we would be a very hot world indeed.
That is exactly correct – without greenhouse gases, the atmosphere would be above the boiling point of water both day and night, and the surface would freeze every night.

March 2, 2011 1:25 am

Philip Peake (aka PJP) says:
the effect is, indeed, logarithmic in nature (Log base e, not Log base 10).
What? The only difference is a multiplicative constant! Except for a constant, ALL log relationships are identical. The base makes no difference at all.

March 2, 2011 1:31 am

Dave Springer says:
March 1, 2011 at 4:06 pm
Tim Folkerts says:
March 1, 2011 at 2:38 pm
“For 400 ppm it clearly takes less than the height of the atmosphere, but how much less?”
APPROXIMATELY 12,000 FEET OVER THE ARCTIC OCEAN. SEE THE GRAPH OF IR SPECTRUM FROM 20,000 FEET LOOKING DOWN THAT IRA POSTED IN THE COMMENTS TODAY.

No, The spectrum from 20,000 feet (6 km) shows the energy emitted by CO2 from about 70 meters below the sensor.
For your estimate, you should use the environmental lapse rate (6.5 K/km), not the dry adiabatic lapse rate (9.8 K/km). That produces a CO2 emission height of 20,177 feet (about 35 meters above the reported altitude).
At the surface, 400 ppm Co2 absorbs 63% of the 15um band in less than 20 meters, 99% in 100 meters. Water vapor requires even less.
In other post, you keep talking about “dense gases” without defining what “dense” is. As the pressure increases, the existing vacuum emission lines get broadened. At the surface of the Earth, these are merged into bands with significant gaps between them. At the surface of Venus (92 atm), the CO2 emission spectra is identical to the expected blackbody emission with no gaps.
In truth, at the surface of the Earth, the spectra is continuous, but with ups and downs. As a result, an insignificant amount of energy is emitted (or absorbed) in the “gaps”.

Bryan
March 2, 2011 1:32 am

George E. Smith
Thank you for your replies above.
I agree with the general content but I have a different interpretation of the historical development of radiative physics.
The classical Rayleigh-Jeans Law was developed in line with classical electromagnetic theory.
Its departure from reality necessitated the quantum Planck radiation formula. Experiment confirms the Planck relationship.
This lead gives I hope some hopefully uncontroversial background.
Work through to the Planck formula and pick the wavelength option.
There is a clear departure between the two formulas for wavelengths shorter than 3um.
However for wavelengths longer than this the two formulas give the same result.
http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

Myrrh
March 2, 2011 1:38 am

Ira – From the berkeley.edu link I posted above where I replied to you, http://wattsupwiththat.com/2011/02/28/visualizing-the-greenhouse-effect-atmospheric-windows/#comment-610932 is a short description of the difference between light waves.
Under Thermal IR it says: “Very high intensity can heat up and kill living tissues”, compare with others eg Green “Normally harmless, can cause blindness or burn tissue at high intensity”
The difference in effect is between heating up and burning re Thermal IR and Shortwave – that’s why UV, which we cannot feel either, burns the skin when it’s intense. If it was these shortwave energies heating the Earth, we’d bit a burnt crisp.
These energies are cold, so the classic physics division into light and heat to describe them.
This scam is a long time in the making, and as all cons it mixes up truth with the lies, that’s what makes a con seem plausible. It doesn’t matter how clever or not one is, if one takes on trust a vital piece of information for calculations which is wrong, it’s going to be gigo, it can’t be anything else.
I see this a lot in scientists arguing for AGW, they take on trust something very basics in real physics from mangled versions in AGWScience, because it’s not in their own field. Because it’s repeated so often and by so many it’s assumed that such are actual real science facts. That’s why the con’s been so successful, imo.
That NASA site I linked to is a prime example of the co-ordinated duplicity – the page I quoted from is from Real Science, before AGW it was known and understood and as you can see they’re still teaching it to children here, but if you look at some of their AGW slant pages you’ll not see it mentioned. One of their AGW pages shows a graphic with two earths, the first shows Solar, (Visible and near shortwave) entering and the second has Thermal IR going out. It isn’t actually a fib at that point, it’s just not the whole picture..

March 2, 2011 2:17 am

Oliver Ramsay says:
March 1, 2011 at 8:02 pm
” That’s my version! ”
It certainly is, and yet another attempt to misdirect in so many obvious ways,
and at so many levels.
” You didn’t show your thermal image, ” – Imagine it please..
” but, if it’s showing the greenhouse hotter than the tree adjacent, it’s because the greenhouse is hotter. ”
– Hotter than it’s surroundings dear chap, an obvious misdirect by you.
” If the greenhouse skin is polyethylene, the interior of the greenhoue will be what is seen for the greater part. If it’s glass, it will be the glass that is emitting.
On a clear day, the greenhouse will not be much hotter than adjacent objects with similar exposure to the sunshine. It will be hotter than the air outside. The other objects would be as warm but some heat was convected away. ”
I have not seen a shoal of red herrings before, well done that man.
With misdirects as well.
Congratulations Sir.
” In practice, a poly greenhouse works about as well as a glass one, in spite of the difference in IR transmission. Conduction/convection cools much faster than radiation in these circumstances. And in many others! ”
Concluding by shooting your own foot off,
was a bit of a let down however.
Thanks for the laughs.

March 2, 2011 2:25 am

Richard E Smith;
My apologies for the confusion. I was wondering why the sudden surrender on the igloo issue…
As for the rest of your comment insisting that the laws of thermodynamics are being broken… I’m a hardcore, in your face, let’s debate any time anywhere anybody but only the direct science not the bunny rabbit population in northern Alberta has declined one percent so that’s why there is more snow in Europe this year SKEPTIC.
And I’ve dug into this many times, my very first foray into the subject resulted in comments just like yours and Don V right after you. I was wrong. (50% of all the people who know me just sat up and said… huh what? he admitted to being wrong?)
I think one of the best layman level explanations ever is Ira’s pervious article on this site http://wattsupwiththat.com/2011/02/20/visualizing-the-greenhouse-effect-a-physical-analogy/
If you want something a little more technical, here’s my own explanation. Insulation isn’t quite the right word, and neither is delayed cooling. But it is what happens, the earth surface does warm if one considers ONLY radiative properties of CO2 and NO other effects, and the laws of thermodynamics are intact. Sorta ticked me off because I had to go looking deeper into the science…and the more I understood, the more of a skeptic I became. But skeptics need to get the basics and stop yelping about cold things being unable to warm hot things, and the laws of thermodynamics being broken. they aren’t.
http://knowledgedrift.wordpress.com/2011/02/27/co2-exactly-how-does-it-warm-the-planet/

Myrrh
March 2, 2011 2:44 am

George E. Smith says,
March 1, 2011 at 5:52 pm
I posted it for the variations of explanations… You could add yours to it.
But see my post above. How is the example of real light bulb which shows the proportion of Visible to Thermal IR at 5/95, and the real life physics from the steel industry which gives a billet of steel at temp X to have 100,000 times more IR than Visible not relevant to this? Is the Sun different?
Objects heating up give off Thermal IR way before the object reaches a degree of heat capable of producing white light, or any visible light at all. One figure I found was that the Sun’s Thermal IR was at 80%. This fits in better with the lightbulb and steel examples, makes more sense to me.
Anyway, the heat we feel on Earth coming from the Sun is Thermal IR, not Solar as Ira has it and as AGWScience teaches. Physics 101. See my post March 1, 2011 at 3:29 pm.
davidmhoffer says: March 1, 2011 at 4:34 pm
Re your artificial/real atmospheres and CO2 “well-distributed”, it isn’t any more than water vapour. CO2 is heavier than air so it would be, unless the lab cylinder is being agitated, at the bottom. CO2 will sink through the atmosphere displacing the air, because one and a half times heavier than air, unless there’s work being done to move it, wind. (Your lab cylinder example as problem with AGW, is also where AGW get their ‘Brownian’ motion from to produce the claim that CO2 is “well-mixed in the atmosphere” by “diffusion”; equal temperature requirement for Brownian doesn’t translate to real atmosphere, it’s convection which moves smells through a room, etc. Good explanation on http://en.wikipedia.org/wiki/Diffusion)
CO2 doesn’t readily rise in air because it is heavier, so CO2 is really localised; what’s produced locally will tend to stay local (plants also breathe out CO2 as well as taking it in for photosynthesis). Something like a volcanic explosion which would force CO2 up into higher altitudes and from there carried in big wind systems, say the jet stream, would move it much further from local, but, say, a factory chimney would release it into whatever local weather system was happening. If a calm day it would simply sink to the ground, or on windy days spread around locally, or on windy wet days, it would come down with the rain. Which comes from the water vapour being lighter than air rising and condensing.
I’ve never seen the raw data from the AIRS satellite survey, (I did see downloadable files but couldn’t get them to work), but their conclusion was that CO2 was not well-mixed in the atmosphere, it was lumpy, and they would have to re-think the data because the wind, local weather and other wind systems, had to be included in understanding CO2 distribution. The standard wind systems don’t cross hemispheres, there’s some mixing at the equator where they meet. http://www.earthfacts.net/weather/windmovement

Myrrh
March 2, 2011 2:48 am

My post to Ira before, before I posted to George and David, has not come up. Should I repost?
[no]

Myrrh
March 2, 2011 3:10 am

OK