Visualizing the "Greenhouse Effect" – Molecules and Photons

Convection currents are the “great equalizer”…. I have a question I’m hoping someone can answer – I thought Al Gore got his graph backwards and the increase of CO2 followed warming – why are we still working with the assumption it creates it???

Can we have one with the number of different GHG molecules represented proportionally for reference? We might not be able to see the CO2 one among all the others, though….

Much of Newfoundland (“The Rock”) is at higher Lat than Minnesota. Though not as biting as “Hide the Decline,” tune-wise the M4GW guys have some professional competition…

Ira,
I think a review of classical thermodynamics is in order here.
You can not win
You must lose
You can not get out of the game.

Although there clearly is a greenhouse effect it is infinitesimal compared to the energy retaining effect of the oceans.
Furthermore the non radiative processes seem to mostly or entirely negate its effect with the real reason for the Earth’s temperature being down to oceanic and not atmospheric energy retention.
Really, we should regard the oceans as part of the atmosphere for energy budget purposes.
The recent suggestion that removing CO2 would cause a snowball Earth cannot be right because there would still be solar shortwave into the oceans keeping them liquid and so a continuing water cycle.
As far as I can see a removal of CO2 would just mean a little less energy in the atmosphere, lower the height of the tropopause a little for a shallower troposphere and redistribute the pressure patterns for a slightly slower water cycle for no significant temperature effect.
The cooling effect of less CO2 would be all or mostly offset by the slowing of the water cycle just as the warming effect of more CO2 seems to be all or mostly offset by a speeding up of the water cycle.

bananabender. Go ahead, try to explain the temperature of the Earth using only the ideal gas law! It can’t be done, you see, if you actually start to think about what you do.

Ira
Sorry to poop the party but over at climaterealists http://climaterealists.com/index.php?id=7457
there is an excellent proof using the physics of black body spectrum which disproves the greenhouse theory conclusively.

Careful – you’ll get Louis, Richard and the “Violation of the 2nd Law of Thermodynamics” crew on to you with outrageous statements like:
“The greenhouse effect heats the earth because greenhouse gases absorb outgoing radiative energy and re-emit some of it back towards earth.”

If all that is going on is absorption and re-emitting radiation there would be no heating of the atmosphere. Heating happens because of the re-distribution of energy through collisions between molecules. The “simple” visualization is thus too simple. The temperature of a gas IS the average kinetic energy of the gas molecules, this is something Roger Pielke Sr. has pointed out a number of times and for many years.

Jer0me says:
March 29, 2011 at 12:43 am
Can we have one with the number of different GHG molecules represented proportionally for reference? We might not be able to see the CO2 one among all the others, though….
Like this one?
http://i55.tinypic.com/a76tw.png
( In proportion: N2-green; O2-gray; Ar-brown; H2O-aqua (2.5%); CO2-red (400 ppmv) )

Further to cal’s points, I don’t understand how CO2 and H2O are able to re-radiate in the way described.
We are told by the AGW crowd that much of the expected (and so far undetected) warming occurs in the middle atmosphere, where the air temps are pretty low (-10C to -30C, up where the planes live).
If a warm surface emits a photon that is captured at this height, and conduction results in almost instant passing on of the captured energy to surrounding gasses (primarily N2) then how do the H2O and CO2 molecules regain enough energy from the comparatively cold gasses to re-emit photons of similar energy?
Surely they can only re-emit much lower energy photons, of similar energy levels to the black-body curve at -20C.

How much of this is theory, and how much observed, in the real atmosphere? Can we see it happening? Can we devise an experiment or observation which would work in the field? Personally, I’ve been struggling with radiative theory, I’ve seen stuff from all sides, and plainly theorists cannot agree. So what do we KNOW?

Stephen Richards (2:05)
the article in Climate Realists makes exactly the same mistakes as all those that think back-radiation somehow violates 2nd law thermodynamics. The last-but-one paragraph sums up his errors quite nicely – it’s basically completely wrong.
Oddly, he describes a thought experiment with a black body and mirrors that he could easily try out, and which would show him he is wrong, Clearly he knows he is right, so doesn’t bother to actually test it.
The other indicator that he is wrong is the massive introduction that is just waffle, before reaching any solid science. Why bother with all that if you are right?

Ira,
Thanks for this, but for me the animation is way too fast to follow. Any chance you could slow it down?

Ira,
I know you have the caveat paragraph “As in the other postings in this series, only radiation effects are considered because they are the key to understanding the Atmospheric “Greenhouse Effect”…… ”
But in comparison to the power of the hydrologic cycle your ‘radiation only’ approach is not unlike saying you are only looking at the retardation effects on the locomotive of hitting insects.
The AGW CO2 warms the world hypothesis depends on the hydrologic cycle. It only works if they can show the ‘water vapor feedback’ which all the GCMs show as a tropospheric hotspot that in the real world does not exist therefore all the models are falsified. You cannot disregard the locomotive of the hydrologic cycle whose effects nobody has been able to quantify but is accepted as the main transport of heat from the surface to the tropopause and the ‘iris’ that increases albedo reducing incoming energy and only worry about the insect collisions of outgoing IR with CO2 in three small radiation bands.

I agree with John Kehr says:
March 29, 2011 at 12:11 am
What he is describing is the Maxwell-Boltzmann kinnetic energy effect in the atmosphere.

[taunting is not an attractive color on you. go ahead and reply, some other moderator will not know why I deleted your little attempt at a humorous humorless polemic. ~ ctm]

This ‘GHG physics’ is bunkum. Let’s take the 15 micron band. 95% is absorbed in 1 m air. That’s why mirages exist – the air above a hot surface is warmed by IR absorption.
OK, the air does re-radiate downwards but a lot of the hot air is convected upwards thus ensuring most of that original IR radiation from the ground never makes it back.
What GHGs do is to increase the adiabatic lapse rate a bit, also raise the tropopause. And because more latent heat means more efficient precipitation, the upper atmosphere dries and it’s easier for the heat to radiate to space.
So, GHG warming is controlled to a near constant level independent of [CO2]. it’s about time that ‘climate scientists’ and politicians realised it.

…rubbish !

Ira,
There are a few reasons that I do not trust “averaged out global mathematical calculations”.
One time frames. Our current calculations fail due to the calculation do not include adjusting for planetary motion, slowdown or unknown surprising factors(such as solar flares, massive eruptions, salt changes, ocean current changes, impacts, etc.).
Next, planetary positioning. Since the suns diameter at it’s equator is the greatest mass and the poles are much smaller to the drifting of the planet between the two.
Thirdly is planetary shape of having a huge diameter equator and smaller diameter poles on a rotating planet.
So, where on this planet or atmosphere does make a difference to any other place taking a measurement.

Ira
Carbon dioxide is a linear molecule. You show it with a bent structure like H2O
Fix that mistake. It makes you look stupid.
When a CO2 or H2O molecules absorbs an IR photon, its linear velocity does not increase. The absorbed photon causes an increase in the vibrational frequency of a bond or combination of bonds (e.g, bending). Fix that mistake.
A vibrationally- excited CO2 or H2O molecule in the troposphere will not re-emit the absorbed photon but will undergo immediate collision deactivation with N2, O2, Ar or H2O. This causes an increase in the speed of these, i.e., they become slightly warmer.
The collision frequency at 1 atm and room temp is about 100 billion collision per sec. Incidently, this is why nat gas in air explodes with great violence, i.e., the reaction goes at the collision frequency.
FYI: CO2 is a weak absorber of IR because it does not have a permanent electric dipole like H2O.

The greenhouse effect hypothesis, and specifically the warming caused by increasing CO2 in the atmosphere goes back to 1896, when Svante Arrhenius wrote an article and then a book that postulated the theory. All kinds of people ran with it afterwards although the theory was later found to be based on grossly erroneous spectra. These gross spectroscopy errors can be seen as conclusively proven wrong in MODTRAN(R) simulations. For a list of references to Arrhenius, including some by people that still believe it to be true look here:
http://www.lycos.com/info/svante-arrhenius.html
For the MODTRAN(R) simulations disproving the theory look here:
http://members.casema.nl/errenwijlens/co2/arrhrev.htm
Although I disagree with his conclusions (he is a warmist), Spencer Weart wrote a pretty thorough history of how this whole AGW thing evolved over the last century, ending with Charles (Dave) Keeling, before going into the modern research and model predictions that are so questionable.
Regardless of his conclusions, I give Weart credit for being quite thorough and his book is worth a read because it encapsulates all the early prominent research that went into building AGW theory as we know it in it’s present form. This book is also a great place to look at all this greenhouse research in one place and to see where the all the holes and leaps of faith are. A pretty complete condensation of the book can be found here:
http://www.aip.org/history/climate/co2.htm
Sadly, and contrary to the whole point of the book, which should have been citations and discussions of the history of AGW research, Weart himself takes the ultimate leap of faith and joins the warmist camp, tainting a great read with his own conclusions. You can see that in his personal notes:
http://www.aip.org/history/climate/SWnote.htm
Best,
Jose

To be thorough, there’s also an “anti-greenhouse” effect. See
http://en.wikipedia.org/wiki/Anti-greenhouse_effect
The atmosphere of Titan is transluctent to some wavelengths, and translucent to part of the surface radiation.
This results in a surface cooler than a surface with NO atmosphere
sun —–> 4 watts 2 watts 2 watts Titan surface 2 watts4 2 watts from atmosphere<——-
2 watts from surface 2 watts from atmosphere
4 watts 2 watts Earth
The earth heats up, reradiating the 2 watts to the atmosphere, which will also heat up. The final
balanc will be
Sun —> 4 watts to atmosphere 4 watts to earth from atmosphere
–>4 watts from sun, 4 watts from earth4 watts from atmosphere to earth
<—4 watts to earth from atmosphere
So the net effect of the surface warming from an infrared absorbing atmosphere is the same as the effect of NO atmosphere.
See Trenbeth's figures here:
http://stephenschneider.stanford.edu/Cl … lance.html
Note that the zero greenhouse effect would apply for those 67 watts absorbed directly by the atmosphere.
Caveats: Working out the temperature drop in a purely radiation
cooled atmosphere, it can be shown that the temperature drop would be
greater than the
moist pseudoadiabetic lapse rate, making a purely radiation
controlled atmosphere unstable. The adiabetic lapse
rate places an upper limit on drop in temperature with height.

Reply to Thomas: I agree that as the adiabatic lapse rate and the tropopause rise, surface temperature will increase. However, the reduction of [H2O] in the upper atmosphere will allow easier radiative heat transport to space. The interaction of this radiative heat transport with the ALR is actually quite interesting.
The evidence of lower [H2O] is fairly conclusive. So, I expect GHG warming from CO2 to be very low.

Stephen Richards: thanks for the link. I did not have enough time for reading the complete article by Postma. Perhaps tonight. My first impression is like yours: it’s over with the greenhouse theory and everything based on it.

When you adjust for atmospheric pressure the absolute atmospheric temperatures of Earth, Mars and Venus only vary by 10-20%. This is despite Venus receiving about 8x as much solar radiation as Mars and 1.9x as much as Earth and the totally different atmospheric composition on all three planets.
Measured Temperature vs Atmospheric Pressure:
0.001Bar:
Mars ~210K, Earth ~220K, Venus ~190K.
1Bar:
Mars (n/a), Earth 288K, Venus 350K.
When you adjust for the different gas composition (relative molar mass) of each planet’s atmosphere the temperature differences are even smaller.
This fact is explained far better by the Ideal Gas Law than any mythical Greenhouse Effect.

Ira Glickstein says:
“7 The energized air molecules emit radiation at various wavelengths and in random directions, some upwards, some downwards, and some sideways. Some of the re-emitted Photons make their way out to Space and their energy is lost there, others back down to the Surface where their energy is absorbed, further heating the Earth …”
As Ira states, heated air molecules radiate. So why are we so concerned about the ‘backradiation’ from CO2? As most of the heating of the atmosphere is by conduction and convection and all gases radiate in close proportion to their temperature, then all gases are greenhouse gases. If it were otherwise, N and O could not radiate away to the vacuum of space. Consequently even if it is accepted that there is backradiation from CO2 ‘further heating the Earth’ (impossible as this means the surface is heating up itself as it is the surface that has warmed the atmosphere in the first place) this effect would be dwarfed by the radiation from the remaining 99% of the atmosphere.
Some commenters on this thread who deride those of us who keep on propounding the second law claim that we misunderstand the position. They say that the greenhouse gases ‘reduce cooling’ (rather than ‘further heating the Earth’). But reducing cooling cannot add heat. In the constant irradiance models that are used to demonstrate the greenhouse effect (e.g. Kiehl & Trenberth’s) the Earth is not cooling down. The most that can be said about the ‘reduced cooling’ theory of greenhouse gases (properly called an atmosphere effect) is that it will reduce heating during the day and cooling at night. Therefore the average temperature may be higher than it would be otherwise (e.g. on the Moon) as the possible minimum is 3K whereas the maximum is determined by the quantity of solar radiance. Those who think this is the greenhouse effect have not understood what real warmists (like K&T and Gavin Schmidt) really believe. Conventional greenhouse theory says that the downward radiation from greenhouse gases raises the Earth’s temperature higher than solar radiation can.

re: Thomas says:
March 29, 2011 at 5:39 am
bananabender. That calculation starts off with the simple mistake of forgetting to include albedo, that Earth reflect some of the sunlight, and thus gets a too high non-greenhouse temperature. (This temperature is measurable as the blackbody temperature of Earth as seen from space and is -19 C)
If you totally ignoreevery factor including albedo, atmospheric composition and incident solar radiation there is still a <10% temperature variation between the atmospheres of Mars and Venus at the same pressure. This is despite Venus receiving 8x as much solar energy as Mars.
I prefer to accept an irrefutable Ideal Gas Law than the idea of "magical greenhouse gases" which defy virtually every basic principle of chemistry.
The calculated value of -19C for Earth without an atmosphere is based on absurd reasoning.

My impression is that there is confusion between thermal transfer between molecules (rotation, vibration etc) and radiation emission/absorption. The first depends on the thermodynamics, the second on quantum physics.
As far as I remember, the absorption of a photon concerns only the electrons which can gain a higher (not stable) energy level. After some time the excited electron will re-emit the received excitation energy as a photon and fall back into the stable configuration. The radiation energy balance would be zero. But may be I have forgotten some essential laws of physics.

This article is incompetent, in the face of definitive experimental data that simply invalidates its premise:
Venus: No Greenhouse Effect
The simple analysis I did, within hours of finding the data on the internet, should have been done nearly 20 years ago. Every scientist who promulgates the greenhouse effect is incompetent. You will find the simplest, clearest discussions about the greenhouse effect on my website. My presentation of the definitive evidence, the first and only such presentation to date as far as I know, should be properly confronted and accepted by the entire science community; I have submitted it to “Physics Today” to get it before that community, but have received no response, which shows a complete lack of integrity and professional commitment to scientific self-correction — a fundamental failing of scientific institutions today.
There is no longer any validity to arguments for the greenhouse effect. The science is settled, and what is needed is re-education of all those like Ira Glickstein who are promulgating false science.

I think a more accurate animation will look like tsunami open sea wave models like this (where the islands represent GHG molecules):
http://www.amath.washington.edu/~dgeorge/talks/movies/TsunamiMovies/IndianOceanAmrMV.gif
It certainly is not like a bunch of projectiles flying around.

Spartacusisfree, if you have any evidence for your claims I suggest you publish them. The general view is that H2O increases as temperature go up, and that seems much more reasonable to me. If you look at different areas of the Earth with different temperature the trend is definitely that warmer areas have more water vapor, so why should the trend be in the opposite direction if the warming comes from AGW? (But at least you don’t violate any obvious law of nature unlike most of the geniuses here)

steveta_uk says:
March 29, 2011 at 3:15 am
You need to explain in the same terms and manner as to why back radiation doesn’t violate black body theory not wave your arms around. I have read the entire doc twice and compared it to the BB theory and can find no problem with what he says. So, explain yourself using the known laws of physics and perhaps we can come to consensus 🙂
Stephen Richards BSc Physic MSc Solid state Physics.

steveta_uk says:
March 29, 2011 at 2:56 am
“…Surely they can only re-emit much lower energy photons, of similar energy levels to the black-body curve at -20C.
Yes, however the temperature of a gas is actually defined as the average kinetic energy of the gas molecules, for example at -20C and not the amount of radiant energy it is emitting. In fact the laws of black body radiation only have a good fit to solid blackbodies which are in thermal equilibrium – something that seldom happens in our chaotic weather systems. The tiny effect the odd molecule of CO2 has is swamped by other processes which drive our turbulent, non-linear system.

“The greenhouse effect heats the earth because greenhouse gases absorb outgoing radiative energy and re-emit some of it back towards earth”.
To be true doesn’t this mean that CO2 must act like a mini sun with an energy multiplying effect.
As an example if the earth contains 1 trillion units of energy. If 100,000 leave the earth’s surface as radiation. Somehow even though half or move does not return to the surface the energy that does return must be greater than 100,000 units. Otherwise there can not be a heating of the earth.
But even this example is not correct as the radiation returning has a cooler energy impact than the earth and a cooler body can not heat a warmer one.

Where Argon ?

Arfur Bryant says:
March 29, 2011 at 9:18 am
I think Cassandra King nailed it. To me, this is a problem of scale which, of course, is not represented in the original graphic.
I would use the following analogy to visualise the scale:
Now that is a perfect and descriptive analogy and explanation of the facts, I really hope Ira reads your post and comments on it because it goes right to the heart of my concerns and I am not a scientist nor do I hold any scientific qualifications so your post really appealed to me and was a joy to read and understand and visualise. I say visualise because that is the key to understanding. IMHO you have created a masterpiece that should have a wider airing in order for us mere mortals to gain a better understanding of the issues.

I am getting a bit depressed by the level of physics being discussed here and in some of the other web sites that we are being directed to. I am beginning to wonder if there is a strategy amongst the warmers to refute the greenhouse effect using bogus physics in order to quote these arguments, say how stupid they are, and thus justify the dismissal of all sceptic arguments as unscientific. Or I might just be paranoid!
There are serious problems with the quantification of the greenhouse effect. There is a serious doubt about feedbacks. There is a serious problem that the “fingerprint” of an enhanced greenhouse effect cannot be identified.
But there is no doubt that the atmosphere absorbs radiation emitted by the earth and eventually radiates it to space at a higher altitude which, being at a lower temperature, means a smaller energy loss. That reduction has to be compensated for by increased radiation losses elsewhere and that means a warmer surface.
This is the overall energy balance scenario and Ira has tried to explain it at a mechanistic level to show what is happening within the climate system. I have problems with some details, as I have already commented, but overall I think it is a good effort.
Some of the objections however are bizarre.
For example some say the sky cannot radiate to the earth because it is warmer yet you can point an infrared detector at the sky at night and measure it! Anyway when a CO2 molecule radiates a photon downwards how does it know the earth is colder and it should not do it!? Of course if the earth is colder the nett energy flow would be upwards (from warm to cold) and that is the only necessary requirement thermodynamically.
Then there are the arguments like CO2 is only a “trace gas” and H2O is a far more powerful absorber. If we a want to make the warmists accept the evidence of measurement we must accept the same rigour. One can measure the absorbtion by CO2 at say 1Km and do the same for H2O. By this altitude both have already trapped all the outgoing radiation at their characteristic absorption frequencies and re-radiated at least once. You can measure the radiation and see the big gaps in the black body spectrum associated with this absorption. You may think that CO2 (or H2O) at such low densities cannot do this but it does and there is already more than enough to do it totally. It is pointless coming up with simplistic arguments to deny these facts when we have data to confirm them.
The greenhouse effect is very badly named but it is a real effect. It would do the sceptic cause a great deal of good for everyone to accept this and then focus on the real issue – what is the effect of further increments of CO2? This question is by no means obvious. When the warmists tackle this question they tend to use the same simplistic arm waving physics that I have been reading above. We need to do a better job not a worse one.

Marc77 says:
March 29, 2011 at 8:01 am
If the “greenhouse effect” had increased, a hot spot would be found over the tropics. This hot spot has not been measured.
Now, let’s see where warming has been measured: mostly where you can find snow or ice. Maybe it could be good to evaluate the “greenhouse effect” inside of snow. First, it is wrong to think that snow reflects light like a giant mirror. Most of the light does enter inside of the snow where it is reflected in all directions by pieces of ice, and after a while, most of the light is reflected out of the snow. So it is similar to a “greenhouse effect”.
Now, the impurities inside of the snow and the spectrum of light will probably have an effect on how much light is absorbed. Up to now, I have not seen any study about this.

Recommend you start here with snow absorption:
http://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4GGLL_enUS382US382&q=%22black+carbon%22+snow+albedo
The so-called tropical upper troposphere hotspot I understand is the mark of the mythical water vapor amplification that turns 1C per CO2 doubling into as much as 3C per doubling. Supposedly the extra CO2 increases water vapor content of the upper troposphere more than lower troposphere resulting in upper troposphere (which is always far colder than the surface) warming more than the surface. “Hotspot” is an inaccurate name since it’s really differential warming between upper and lower troposphere.
The increasing magnitude of the differential warming, if any, is difficult to measure and controversial. I believe notoriously poor GCM modeling of clouds is why the models are wrong. If the water vapor being delivered to the upper troposphere increases so does the amount of heat carried away from the surface by evaporation and convection and it condenses at an increased rate rather than giving the upper troposphere a higher absolute humidity. Thus evaporation, convection, and cloud formation is a negative feedback that negates the effect of more water vapor due to warmer surface temperature. There are several well developed hypotheses on this effect. The best IMO is
http://www.scribd.com/doc/25071132/The-Saturated-Greenhouse-Effect-Theory-of-Ferenc-Miskolczi
which is basically saying that the atmosphere, with regard to water vapor greenhouse warming, is saturated and we can’t get any more greenhouse warming out of water vapor – we can get additional surface warming only from increases in non-condensing greenhouse gases like CO2 and methane. I am in fundamental agreement with the conclusion simply by considering that the earth has never experienced a runaway greenhouse effect which water vapor amplification must certainly entail. So regardless of whether Miskolczi is right something is putting a ceiling on the maximum surface temperature and this appears to me to explain why. CO2 levels in the remote past have been several doublings greater than present and the global average temperature was several degrees higher fitting perfectly with there being no water vapor amplification.
My own pet theory is that CO2’s primary role is increasing the earth’s average temperature from below freezing to above freezing and this is accomplished by the first 100ppm in the atmosphere. CO2’s LWIR absorption curve is linear for low concentrations of the gas and becomes logarithmic in greater concentration (which has been known for over 150 years since John Tyndall experimentally measured it). It serves as “kindling” to get the water cycle going. Once the water cycle is going it takes over as the primary greenhouse gas and unlike CO2 is self-limiting because it’s a condensing gas. After that CO2’s role is limited to about 1C per doubling. There isn’t enough recoverable fossil fuel in the world to do more than two or three doublings which might possibly mean we could end the ice age and in a matter of thousands of years see the earth get green from pole to pole (which is its usual state – no polar ice caps at all). The downside of having a vastly increased amount of arable land is that ocean levels will return to their normal non-ice age level which is about 100 meters higher. That will take thousands of years to happen. No plants or animals will have any trouble migrating to higher ground. Humans have the bigger problem as we built a lot of immobile crap very close to the ocean under the mistaken impression that ocean level rises and falls only with the tides and is constant otherwise.

“For example some say the sky cannot radiate to the earth because it is colder yet you can point an infrared detector at the sky at night and measure it! Anyway when a CO2 molecule radiates a photon downwards how does it know the earth is colder and it should not do it!? Of course if the earth is colder the nett energy flow would be upwards (from warm to cold) and that is the only necessary requirement thermodynamically”.
Measure what though. See below that might be relevant. From the slaying blog
And this has been discussed before but the issue is not whether radiation travels downwards. It is whether it has a warming impact if it returns to the surface.
From slayingtheskydragoncom/en/blog/102
Lord: “Back radiation can be simply demonstrated by pointing a simple infrared detector at the underside of a cloud. Try it.”
Chorus: “My IR detector only cost $60! Simple! Agreed! Agreed!”
Slayer: “Clouds do not absorb and re-radiate heat back to Earth. Clouds add THERMAL MASS which takes longer to heat and cool. Warmists ‘support’ this false hypothesis with IR thermometer readings, but the IR readings of a hot Barbie is the same from any distance; ENERGY is not. Your $60 REMOTE thermometer is not measuring the radiant energy you are receiving, it is measuring the resonance of the Barbie.”

I did not say precipitation occurs in the stratosphere, it’s much lower down. And it’s easy to prove the optical physics in the climate models, which predicts the cloud part of ‘global dimming’, is wrong by looking at clouds as droplets coarsen prior to raining: the base gets darker, exactly the opposite of what the models predict.
After NASA discovered there was no experimental proof of this cooling, they published this: http://geo.arc.nasa.gov/sgg/singh/winners4.html
Twomey’s physics, which he warned could not be extrapolated to thicker clouds, is based on Mie theory. There is no ‘surface reflection’ but it apparently fooled climate science, hence AR4 contained the imaginary cooling.
So the high feedback hypothesis was always the artefact of a scientific mistake. Until it’s corrected, no model can predict climate. Correct it and out pops another AGW, ‘cloud albedo effect’ heating that explains palaeo-climate [probably via phytoplankton bio-feedback] far better than CO2-GW, which if not net zero, is much lower than claimed.

The argument “backradiation warms the surface of the Earth” is often used when discussing the greenhouse effect. Is it fair to infer from this argument that an object’s temperature will always be higher in the presence of backradiation than it would be in the absence of backradiation? If so, I disagree.
Consider two disjoint blackbody objects (a spherical active object, and an inert object) in the vacuum of cold space. Assume the internal thermal conduction properties of each object are such that the surface temperature is uniform. By blackbody I mean the surface of an object (a) absorbs all electromagnetic energy incident on it, and (b) radiates electromagnetic energy in accordance with Planck’s blackbody radiation law. By “active object” I mean an object with a constant internal source of thermal energy–e.g., radioactive decay. By “inert object” I mean an object that has no internal source of thermal energy.
The active sphere in isolation will experience no back radiation–i.e., all radiation leaving the sphere will escape to space. The active sphere in the presence of the inert object will experience back radiation–i.e., some of the radiation emitted from the active object will be absorbed by the inert object–causing the inert object’s temperature to rise–causing the inert object to radiate energy, some of which will be directed “back” toward the active object. Provided there is no object-to-object thermal conduction or convection, I believe the steady-state temperature (the temperature when the rate of energy leaving an object is equal to the rate of energy entering the object) of the active object will be higher in the presence of the inert object than it will be in isolation. However, if conduction and/or convection between objects is allowed, then depending on the rate of energy transfer via conduction / convection, in the presence of the inert object and hence in the presence of backradiation the steady-state temperature of the active object can be either higher or lower than in the absence of the inert object. If true, then the argument that “backradiation warms (i.e., increases the steady-state temperature of) the active object” is not true.
Ira explicitly stated that his arguments apply only in the absence of conduction and convection; and with that caveat, I agree. However, since conduction and convection are both present in the Earth/Earth atmosphere system, I am not convinced that “greenhouse gas backradiation” produces a net increase in the surface temperature of the Earth. Any attempt to discuss the “greenhouse effect” in the Earth’s atmosphere without including a discussion of conduction/convection is in some sense like trying to get your car to the top of a steep hill by pushing–you’ll waste a lot of time; and when you’re done pushing, your call will likely be farther down the hill than when you started.

Matt
All this might do is slow the rate of cooling. It will not warm the planet. And as radiation travels at the speed of light\(and the quantity of CO2 is small) the slower cooling if it occurs would be very minimal.
But there is still the problem of a cooler body heating a warmer one. If radiation leaves earth’s surface at say 10 degrees and collides with CO2. Won’t this lower the potential energy in the radiation. So when it returns (if it does) its vibrational energy will be lower than the surface of earth. So can not warm the planet unless the planet has in the mean time cooled by more than the radiations potential energy.

Ira
I always had a problem with the logic of the GWG theory. And thankfully all the queries I had were answered and explained in the brilliant slayers book.
I now debate with warmist in various ways. One is to dispute the GWG theory as per the slayers book. Another to dispute the extent of the warming assuming the GHG theory is correct. Another to point out the pointlessness of CO2 taxes and cap and trade etc.
Assuming the flawed GHG theory is almost a fact (as you are doing) without understand how weak this theory is, and its flaws, was a hindrance not a help to me.

Ira, I really enjoy your contributions and the discussions they create. With so may ideas, one really has to think and ponder what is the most realistic explanation.
After reading through the various contributions to this thread, it seems to me that the dualistic nature of electromagnetic radiation is not taken into account sufficiently. We talk of wavelength (the wave nature of electromagnetic radiation) and photons (the particle nature). Your diagrams are of molecules being hit by photons. So it is like a billiard ball situation.
Someone said it was more like a tsunami wave. While I agree with that somewhat, radiation is not a wave front. It is more like a constant field. The billiard ball type diagram makes it seem as though the chance of a CO2 molecule being hit is small. And for one ray of radiation it is. But, with a constant field of radiation, the CO2 molecule is always being hit by some ray of radiation.
Nevertheless, it is hard to understand how this could cause enough increase in the water vapor in the air for the water vapor to produce the increase in atmospheric temperature that the models show.

mkelly says:
March 29, 2011 at 11:20 am
If has shown in ( http://jennifermarohasy.com/blog/2011/03/total-emissivity-of-the-earth-and-atmospheric-carbon-dioxide/#more-7739) that at STP the emissivity off CO2 is almost zero then no back radiation can take place.

You were doing fine until you said no back radiation takes place. CO2 has no line emission in a cold dense gas. It has an absorption line. After absorption it loses the energy kinetically via collisions primarily with oxygen and nitrogen. This thermalizes the gas mixture i.e. sensibly warmer. The air is ALWAYS emitting a continuous blackbody spectrum! Everything with a temperature above absolute zero emits a continuous blackbody spectrum with a peak frequency that rises with rising temperature. The higher the peak frequency the more energy in the emission. This is where the downwelling radiation comes from and its existence is without doubt.

Dave Springer
” This is old stuff.” OH IS IT NOW! That’s funny NOWHERE in the 512 pages of Tyndall’s great experimental work does he EVER mention backradiation, nor does he mention the term greenhouse EVEN ONCE. You are blowing a lot of hot MOIST air and I’m calling you on it. Bring out some of that old stuff and let’s find out!

Dave Springer says: Everything with a temperature above absolute zero emits a continuous blackbody spectrum with a peak frequency that rises with rising temperature. The higher the peak frequency the more energy in the
It’s not a peak frequency. It’s a median energy. Blackbody spectrum is a spectrum with a central energy and energys higher and lower thus forming the BB spectrum.

Gerge E Smith says: My impression is that there is confusion between thermal transfer between molecules (rotation, vibration etc) and radiation emission/absorption. The first depends on the thermodynamics, the second on quantum physics
I would lkie an euro for every time I’ve said this on this site and stil people continue.

Dave Springer says:
March 29, 2011 at 12:30 pm
The air is ALWAYS emitting a continuous blackbody spectrum! Everything with a temperature above absolute zero emits a continuous blackbody spectrum with a peak frequency that rises with rising temperature. The higher the peak frequency the more energy in the emission. This is where the downwelling radiation comes from and its existence is without doubt.
Of course it does not. Only a black body emits a black body spectrum. The atmosphere is not a black body. If it were a black body we would not be able to see the sun! Indeed most things are not even close to black bodies – that is why the world is colourful. Did you not see the spectral distribution looking up at the night sky that was posted about a week ago? It looked nothing like the black body curve. It was completely dominated by the greenhouse gas spectral lines as one would expect. The atmosphere is pretty transparent in the visible region and has an atmospheric window around 10 micron where there is not much absorption, so these wavelengths are absent in the downward radiation as well.

The greenhouse effect and the energy retaining effect of the oceans are different things. The atmosphere and the ocean may retain heat, but the atmospheric heat retention is infinitesimal compared to the heat retention of the oceans. The greenhouse effect changes the amount of heat that flows out of the system.
The oceans absorb the vast majority of the RADIATIVE ENERGY stiking the planet from the sun. This RADIATIVE energy leaves the planets surface by a route proportional to the density of the atmosphere (not just GHGs) and the speed of light. That’s why Stephen Wilde said what he said. ALL the energy on this planet comes from the sun ~ 99.9%. The Earth approximates to a blackbody in as much as it’s surface albedo modifys the amount of RADIATION that is reflected back into space. A blackbody cannot re-absorb radiation it has given up after equilibrium is reach. After equilibrium all radiation striking the BB is reflected away that’s why the earth and the moon cannot heat the sun by radiative reflection. After bombarding the earth with radiation for 5 billion years they are as near as damn it at BB equilibrium unless the sun’s radiative output changes.

cal says:
March 29, 2011 at 12:12 pm
Cal, thank you for your response.
My argument has little if any relevance to the computation of the surface temperature of the Earth in the presence of greenhouse gases. However, it does have relevance to Ira’s statement: “That said, how does this visualization help us understand the issue of “CO2 sensitivity” which is the additional warming of the Earth Surface due to an increase in atmospheric CO2? Well, given a greater density of CO2 (and H2O) molecules in the air, there is a greater chance that a given photon will get absorbed. Stated differently, a given photon will travel a shorter distance, on average, before being absorbed by a GHG molecule and be re-emitted in a random direction, including downwards towards the Surface. That will result in more energy being recycled back to the Surface, increasing average temperatures a bit.”
In particular, his statement implies backradiation results in (a) more energy being returned to the Earth surface, and (b) an increase in average temperatures. If any situation can be constructed where (a) backradiation does NOT result in more energy being recycled back to the active object’s surface, and/or (b) backradiation does NOT increase the active object’s surface temperature, then in my opinion Ira’s statement requires additional justification.
By applying Planck’s blackbody radiation law to the surfaces of (1) an active, uniform-surface-temperature sphere and (b) a thin, co-centered, disjoint, inert, planar, uniform-surface-temperature, circular annulus, it can be shown that in the presence of object-to-object conduction, the rate of inert-object to active-object backradiation, although present, can be made less than the rate of conductive energy transfer from the active object to the inert object. This will result in a lower active-object temperature. Furthermore, even in the absence of object-to-object conduction, increasing the outer radius of the inert annulus beyond a certain point, which provides a larger surface area from which backradiation can originate, results in less backradiation, not more. It may be true that greenhouse gas backradiation warms the surface temperature of the Earth, but Ira’s statements that (a) adding more greenhouse gas will increase the amount of backradiation, and (b) that the additional backradiation will warm the surface of the Earth do not convince me. I want to see an analysis of how and to what degree conduction and convection affect the amount of backradiation received by the Earth’s surface relative to the rate of energy transfer from the Earth’s surface by these thermal transfer mechanisms. For example, wouldn’t the increase in the amount of greenhouse gas increase the rate of conductive thermal transfer and possibly convective thermal transfer from the Earth’s surface to the atmosphere? If so, which effect is dominant, and under what conditions?

cal says:
March 29, 2011 at 11:41 am
If it returns to the surface and does not warm it must be totally reflected. If it is totally reflected then the surface cannot emit at that wavelength either (basic law of thermodynamics). Therefore it is not possible for radiation to be emitted from the surface, absorbed by the atmosphere and re-radiated downwards without increasing the temperature of the surface.
Cal, I have to disagree. Consider a spherical active Earth surrounded by an “atmosphere” comprised of co-centered, thin, blackbody-surface (both sides), spherical shell with a vacuum filling the space between the Earth’s surface and inner surface of the shell. I know this isn’t a gaseous atmosphere, but in the sense that the shell surrounds the Earth, I will take license and call it an atmosphere. In isolation, the Earth’s surface temperature will be (a) directly proportional to the fourth root of the Earth’s internal rate of energy generation and (b) inversely proportional to the square root of the Earth radius. No backradiation exists for the Earth in isolation.
When the shell is added, because in steady state the shell must radiate to space the energy generated internal to the Earth, the steady-state temperature of the shell (for a thin shell, the inner and outer shell surface temperatures will be very near the same) will be directly proportional to (a) the fourth root of the Earth’s internal rate of energy generation and (b) inversely proportional to the square root of the shell radius. Backradiation (radiation from the inner shell surface to the Earth) will exist. Since the radius of the shell is greater than the radius of the Earth, the shell’s surface temperature will be lower than the Earth surface temperature in isolation. If a thermal conduction path is provided from the Earth to the shell and if that path supports a rate of energy transfer greater than the radiative rate of energy transfer from the shell’s inner surface to the Earth, the Earth’s temperature in the presence of the shell with conduction will be lower than (a) the Earth’s temperature in the presence of the shell without conduction, and (b) the Earth’s temperature in absence of the shell. Since radiation is being emitted from the active object (the Earth) and backradiation from the inert object (the shell/atmosphere) exists whenever the shell is present, how can you claim backradiation from the shell/atmosphere must warm the surface temperature of the active object?

Ian W says:

The AGW CO2 warms the world hypothesis depends on the hydrologic cycle. It only works if they can show the ‘water vapor feedback’ which all the GCMs show as a tropospheric hotspot that in the real world does not exist therefore all the models are falsified.

The water vapor feedback is now extremely well-verified, especially over timescales of months to a few years. See http://www.sciencemag.org/content/310/5749/841.abstract and http://www.sciencemag.org/content/323/5917/1020.summary
Amplification in the tropical troposphere (the so-called “hot spot”) is also well-verified over these timescales. Over the multidecadal timescales, the data is simply too uncertainty to reach any definitive conclusions but it is difficult to imagine mechanisms by which the physics responsible for this would break down on these timescales without also breaking down on shorter timescales.
Dave Springer says:

The whole brouhaha over scary global warming rests on the wholly fabricated idea that CO2 greenhouse warming puts more water vapor in the atmosphere and that, because water vapor is a powerful greenhouse gas, it constitutes a positive feedback that turns 1C per doubling into 3C per doubling. There isn’t a shred of empirical evidence to support that belief and IMO overwhelming evidence that the feedback is actually negative – the water cycle speeds up which serves to mechanically transport heat from the surface by evaporation and convection to the cloud deck where it then has an easier radiative path out to space.

The only way that radiation escapes to space is by stuff radiating and the amount of radiation that stuff emits is determined by the temperature. Hence, your statement amounts to the hypothesis that the “hot spot” ought to be more pronounced, not less pronounced, than the models predict.
The models already take into account the negative feedback due to the lapse rate, which basically seems to be what you’re describing. But a literal interpretation of the claim that the hot spot is missing would be that the models are including a negative feedback that does not exist.

If the water vapor being delivered to the upper troposphere increases so does the amount of heat carried away from the surface by evaporation and convection and it condenses at an increased rate rather than giving the upper troposphere a higher absolute humidity.

Except that the satellite data seem to show otherwise, as I noted above.

Thus evaporation, convection, and cloud formation is a negative feedback that negates the effect of more water vapor due to warmer surface temperature. There are several well developed hypotheses on this effect. The best IMO is
http://www.scribd.com/doc/25071132/The-Saturated-Greenhouse-Effect-Theory-of-Ferenc-Miskolczi
which is basically saying that the atmosphere, with regard to water vapor greenhouse warming, is saturated and we can’t get any more greenhouse warming out of water vapor – we can get additional surface warming only from increases in non-condensing greenhouse gases like CO2 and methane.

If that’s the best, I can’t imagine what the worst looks like! Miskolczi’s paper is basically nonsense with lots of extremely strange things like misapplying the virial theorem.

BigWaveDave says:

The constant compression of atmosphere by gravity results in higher pressure, density and temperature at the surface. No GHG’s are necessary for this..

Your notion doesn’t even satisfy the 1st Law of Thermodynamics! In the absence of a greenhouse effect, the surface temperature of the earth is set by energy balance considerations. So, unless you are proposing a large source of energy…e.g., that the earth’s atmosphere is undergoing continual gravitational collapse, which would certainly be a novel hypothesis…your notion is completely in violation of known laws of physics.

Two main mistakes as pointed out above.
1. Absorbing by CO2 at 15 microns does not speed up the molecule, it raises its vibration state, and may change its rotation state (15-micron side-bands).
2. Photons are not emitted by molecules other than GHGs and not at wavelengths other than those where they have spectral bands.
Other than that, fine.

“”””” cal says:
March 29, 2011 at 10:12 am
I am getting a bit depressed by the level of physics being discussed here and in some of the other web sites that we are being directed to. I am beginning to wonder if there is a strategy amongst the warmers to refute the greenhouse effect using bogus physics in order to quote these arguments, say how stupid they are, and thus justify the dismissal of all sceptic arguments as unscientific. Or I might just be paranoid!
There are serious problems with the quantification of the greenhouse effect. There is a serious doubt about feedbacks. There is a serious problem that the “fingerprint” of an enhanced greenhouse effect cannot be identified.
But there is no doubt that the atmosphere absorbs radiation emitted by the earth and eventually radiates it to space at a higher altitude which, being at a lower temperature, means a smaller energy loss. That reduction has to be compensated for by increased radiation losses elsewhere and that means a warmer surface. “””””
Well there is one thing seriously wrong with your thesis, cal.
The earth’s surface is mostly hotter than the air is at altitude. Therefore the surface emits at a higher emission level than the cooler atmosphere, and moreover it does so in a generally higher frequency (lower wavelength range; per wien’s Displacement Law.
So the very hottest desert surfaces, are emitting plenty of radiation that goes right on by the CO2 15 micron absorption band right out into space unimpeded by CO2. And as you get higher, and the atmosphere gets colder and less dense, the absorption bandwidth of the 15 micorn CO2 band keeps getting narrower; each and every one of the high resolution lines in the CO2 band keeps get less broadened by doppler, and collisions, as you go up in the atmosphere, so it keeps on absorbing an even lower fraction of the surface emitted radiation, and escape gets easier, as you go higher. So you are not dependent on energy being transported to the highest least dense, and coldest upper reach4es of the atmospehre, and then expecting that material to radiate the entire heat load of the planet.
And if you go in the opposite direction (atmospheric emissions are isotropic, so only half of it goes down, the downward path (that “back radiation thing”) sees a continuously warming, and denser atmosphere so the CO2 absorption spectrum gets more and more opaque for the downward radiation, instead of more and more transparent for the upward escape path.
So the earth des not sit at some BB Temperature of 255 K due to some high altitude evanescent layer of colder rarified atmosphere. Certainly the energy borne aloft as heat by conduction, convection, and evaporation (latent heat) must eventually be radiated by higher altitude gases; but the very ground itself, is making a significant direct contribution to the radiative cooling that augments the other (thermal) processes.
The earth is anything but Isothermal, and we should not expect it to radiate some isothermal radiation spectrum.

Harold Pierce Jr says – – –
Classic error in thinking and the modeling. The concept that once the CO2 molecule “absorbs” the IR, and becomes vibrationally excited, it “losses” that energy to the O2 and N2, and thus “traps” the energy in the atmosphere.
NOT TRUE! There is a distribution of energies of the ensemble of molecules. There is EXCHANGE. Therefore, collisions between O2 and N2 molecules on the “high end” of the distributed energy, LOSE that translational kinetic energy to CO2 and H2O molecules.
WHICH, can…with significant probability, re-emit an IR photon.
That’s why the REAL question here is what is the “optical transparency” of the ensemble of the atmosphere, and has the increased CO2 since WWII changed that number significantly.
Studying the work of Miskolczi, Ferenc M. 2010. “THE STABLE STATIONARY VALUE OF THE EARTH’S GLOBAL AVERAGE ATMOSPHERIC PLANCK-WEIGHTED GREENHOUSE-GAS OPTICAL THICKNESS”, Energy and Environment, 21, 243-262 , indicates that this is the case. I’m well aware of the critics of Miskolczi’s work. I’m also aware that based on “empirical observations” up to 1942, Dr. Elsasser came to the same conclusion as Miskolczi, and neglects CO2 in his “general radiation chart”, which has been used successfully to model day to day heat up and cool downs for “weather forecasting” since publication of his paper, “On the IR Heat Balance of the Atmosphere”, (Harvard Met. Series, 1942)
Dr. Glickstein: I hope you are retired, and have the time to examine these matters in depth. I, alas, still have to work for a living.
Max 🙂

If backradiation was a phenomena that would heat up earth surface it would also heat up the sun up to the core.
By using Stefan-Boltzmann the non-GHG surface temperature is found by using E = sigma T^4 (SB) where E can only originate from the sun. If now T would go up further because of GHG, this would mean more energy input would be needed. So where does this come from, are GHG capable of generating energy? Many people seem to think so, but what about the following?
If we look at a CO2 layer as a plate with T2 above earth, you have something like the classic example of radiation between two plates here, where the sun would heat the lower one which is T1.
So yes radiation will go both ways, there is ‘backradiation’ and I go with that. But read that in the state (equation 19.2) where also plate number two would be T1, Qnet will be zero. Surface 1 will never get any warmer by the (back)radiation, despite the accumulated (heat)energy in plate 2 and radiation going everywhere. Read from this that radiation is energy but never heat.
So you can make calculations with multiple layers (like CO2 layers) and the result will be the same. T1 will not get any warmer with Qnet getting zero, and all the layers acting as insulation (like some people think CO2 does) and all plates actually permanently getting radiation from both sides. (Earth atmospheer would also be forced to become T1 from the surface up if it was’nt for gravity).
Now think about multiple plates where the sun’s surface is the first plate and earth the second etc. So the greenhouse effect says that the second plate is supposed to get warmer by backradiation from the plates next in line? Then also the first one, the sun’s surface will get warmer (no matter how tiny) by this backwards phenomena. The sun has many more layers, but this process will go on up to the core! The source of the energy!
Well, what is wrong here. The problem is that in our real universe the temperature of the sun in space is the driving force, telling all other layers down the line what temperature they must take on, in its path to the 3 Kelvin of space and not the other way around.
With new layers somewhere in the line, the temperature of the layers behind the new one will simply go down to establishing a larger dT maintaining the same energy flux.
Yes, it’s that pesky Second law, that in fact is constantly trying to lower the temperature of the sun.
So what are the tricks with radiation that many people don’t see? For starters I want to say that the photons of EM radiation can be regarde as cold, only interaction with matter gives any thermal energy (to get a temperature) which is taken away (partly) when a(nother) photon leaves.
Most greenhouse effect statements/sites claim an energy balance on earth surface because of the First law, the greenhouse theory makes fame by using energy in-out balances etc. convincing everyone who has no clue about thermodynamics. But this is dead wrong, the Second law rules here and this means simple energy conservation is not what determines radiative equilibrium temperature at the surface.
The earth could conserve it’s energy by accumulating it until it would be as hot as the sun, there is nothing against the First law with this.
So in GHG physics T of earth surface is supposed to go up with while receiving the same amount of energy from the sun. Now we know the Second law wants to establish a dynamic radiative equilibrium at the surface with a certain temperature but also that T = dE/dS, so this means that for T to be able to go up with backradiation Entropy must decrease during the absorption-emission process?? That will never happen.
Looking closer it works like this:
Why does the sun heat the surface to T? Because HQ radiation from the sun can leave earth as LQ IR radiation (to the cold space) in the process gaining entropy while raising kinetic energy as potential WASTE HEAT on the surface (and they don’t call this irreversible for nothing, the downgraded (photon)energy won’t be able to do the same trick at the surface again).
The radiation Quality is expressed as theRadiation Energy Density
Some LQ IR returns (backradiation), but it can never ever create more heat here. Because in that case it would have to leave with less energy so as even lower quality IR, and hey …… this can only happen at a LOWER surface temperature (think of the BB-spectra of earth next to the sun, all the energy flows from the high spectrum to the low one, anyone thinks some energy goes the other way here?).
See the contradiction, that’s the mighty Second law of thermodynamics in action that says: it’s all wrong with this heating by backradiation philosophy.
So backradiation will simply leave in a reversible proces (like reflection) without leaving waste heat, and with the same frequency as it had before and bounce whatever way it wants with no effect on the surface. It’s like in the Qnet = zero situation between the two plates (lotsa radiation, no more heating by the cold photons).
So what is ‘the heat’ that can’t go from low to high temperature, warming the earth surface and why the confusion?
Maxwell’s classic Theory of Heat states: heat is something which may be transferred from to another, according to the Second law of thermodynamics.
In any case, heat transfer needs matter which has a temperature (as kinetic energy) and another piece of matter at lower T. Radiation has no temperature and can never ever represent heat. And so the photons of radiation can be regarded as cold.
Heat is the waste from the irreversible radiation phenomena happening due to what the Second law dictates and is equivalent to the entropy gained and what is called dissipation of energy.
Heat can be released when a photon interacts with matter. Many think ‘the heat’ has to do with all the energy (E= h x v) related to the cold travelling photon. But we have seen that this is not the case, this is imaginary heat (which is not heat but energy) that is never released as long as matter is’nt involved. Energy is only released when the SWR photon disappears in the matter and after that heat from this matter may flow if other colder matter is present, but this heat is not equivalent with the photon energy but is a function of the temperature difference between surface temperature and colder matter above it (like Q = k*A*dT). If there is no colder matter, there is no heat (dT=0).
If earth had no atmospheer, the photons would warm earth surface to SB temperature but no heat would ever be exchanged. Then if there was a layer of CO2 around it at say 10 meters or 10 km, this would create backradiation, but the vacuum inbetween would be as cold as the 3K space, and the backradiation would not make the surface warmer, and there would be no heat despite all the radiation.
Now because heat is flowing from earth surface we know we have a second irreversible process (waste heat, making entropy rise) we also know for sure the new lower energy photon can never release heat at this temperature where it came from ever again, so to think backradiation can go beyond that and even create a higher temperature is impossible by the Second law of thermodynamics.
So the heat coming from the surface is the part of the solar radiation that did’nt get radiated away (directly) as IR (and the total energy of this IR is thus lower than the LWR that hits the surface). Heat is the part that has nothing to do with radiation, and the IR that left has nothing to do with heat.
And so we get the surface balance: IR = LWR – HEAT. So the IR that leaves the surface does’nt only have a lower frequency, but the total energy of it is also lower than the incoming LWR. This is the second blow for the imaginary effect of backradiation.
It is this HEAT only that warms the first layers of the atmospheer and gives the ground temperature’s measured (in air, so does not even represent the surface), and it can only take place by conduction from surface to air initially, it must be transported from the surface at T1 to matter at T2 and it finds its way up (conduction/convection – radiation) to space separated from the IR photons that left the surface.
Papers about the sun that are not infected with the greenhouse virus go along the lines of my view. Photons jiggle around for tenthousands of years from layer to layer, and they do not heat the core. This degradation of high quality X-ray photons to relatively low quality optical photons, is only to be expected from the Second law of thermodynamics.
Further: a photon can only travel a tiny distance before running into another hydrogen nucleus. It gets absorbed by that nucleus and the re-emitted in a random direction. If that direction is back towards the center of the Sun, the photon has LOST GROUND! It will get re-absorbed, and then re-emitted, over and over, trillions of times. The path it follows is called a “random walk”

I’m stunned that there is debate about the ability of one radiating object being able to heat another radiating object. It is so numbingly obvious that this happens that it begs the question: What the hell would keep it from happening?!?
As for which direction molecules radiate energy, try thinking of each of them as isotropic radiators (they’re not, but the principle applies). Except for geometry limitations of the molecule (asymmetric construction), they will behave like an isotropic radiator and radiate equally in all directions. In the atmosphere, where molecular orientation is assuredly random, even asymmetric molecules on average will not favor up vs down vs over there when it comes time to shed their packet of new energy.
Here’s another mental widget to help get your head around this. We’re talking about radiation here, remember. Picture a flash bulb sitting in free space. Imagine it is lit off. Imaging a sphere of light radiating away from the bulb. Imagine that light hits other things. Imagine some of those things are other lightbulbs. Some lit, some not. Now try to understand – there is no intelligence delivered with that sphere of light. It simply illuminates any surface it touches. That includes other lit surfaces. The bulbs don’t know this is going on and don’t care. They are just following the rules of thermodynamics.
Now the test – you put a very sensitive light sensor in the lab space and it has lenses so it sees but one single bulb. The entire field of vision of the sensor it filled with that bulb. Turn on the bulb and notice the sensor response. Now turn on another bulb that is conveniently located behind the sensor and so out of it’s sensing view. Note that the sensor detects that new light coming from the only thing in its view and it registers a higher light level than before. Some call it BS. In fact that just happened in this thread, but it is true that radiating objects light up other radiating objects in all parts of the spectrum including IR.
Ever wonder why three logs stacked in a pyramid will burn to ash but one log alone will quickly stop burning and turn cold? It is because the logs radiate heat onto each other while they burn and heat is one of the three essentials for combustion.
Nuther example because I sense a lot of ignorance here. You are sitting in your kitchen typing on your laptop, filling the WUWT blog with ignorance. It is dark out, and very cold – snow everywhere. You look at the outside thermometer and it is 5ºF – damn cold. You pull aside the drapes on your double paned sliding glass door so you can look out at the beautiful snowy wonderland. And after a few minutes you start to feel cold where before you were quite comfortable. How can that be? It is 72º in your kitchen – how can you feel cold? You granny comes over and pulls the drapes closed, calls you a dummy and that you’re going to freeze if you leave those drapes open. What does granny know? Did you notice too you were cold only on side of you facing the snowy winter wonderland?
Granny knows your body is radiating the maximum possible heat out of the house and into that winter wonderland. If you pull the drapes closed that heat loss stops. Why? Think about that then send your granny a card. A real card, not a lame iCard, and let her know how smart she is.

Well ok, I guess, although many here don’t seem to think it is ok. But why is the sensitivity of atmosphere to an additional molecule of CO2 logarithmic? Your model implies that it wouldn’t be.

@DP
It’s a shame none of your examples support your argument.
The first experiment is simply completely wrong.
The three logs burn better because a pyramid allows much more air into the fire and increases the surface area exposed to the fire promoting combustion. Boy Scouts 101. Nothing to do with radiation.
The reason it is cold near the window is because:
a) The window is a much poorer insulator than the walls. This means the air near the window is cooled by conduction and radiation to the outside and convection on the inside surface of the window.
b) The window is also further from the fire and receives much less thermal energy according to the inverse square rule of radiation.
c) The window has a very low albedo so it doesn’t reflect heat back into the room.
If you repeated the experiment with triple glazed windows it wouldn’t work.

If you repeated the experiment with triple glazed windows it wouldn’t work.

Multiple panes of glass work against conduction. They are useless against radiated heat unless they are designed (coated) to radiate IR back into the room in which case it is exactly the same as drawing the drapes closed but much more expensive. Pick up a good science book and don’t put it down until you understand how radiated energy works. Then teach your kids.

DP;
How is it possible for a pyramid of logs to allow more air to the burning part of the log that a log standing alone without competition for that air from other logs? It really is the mutual heating that sustains the burn.>>>>
Thank you thank you thank you thank you! What a wonderful, obvious, easy to understand example! Mind if I borrow it from time to time? I’ve been relying on my igloo example of cold things radiating heat to warm things and have become exasperated with the nonsensical objections.
As for bananabender….
If you’d actually taken Scouts 101 pretty much the first thing you learn is that any logs of a decent size simply will not burn well unless the burning faces are used to heat each other up. In your own example, if the pyramid of logs promoted surface area exposed to air, why wouldn’t the logs burn from the outside in instead of the inside out? If you took Scouts 201 you’d also know that arranging the logs in layers, each layer a set of parallel logs at right angles to the layer below, makes a fire that puts the pyramid to shame. It creates a whole series of surfaces radiating at each other to achieve much higher temps.

DavidM
I’m just reading this article. This section below seems at variance to your very dubious Igloo example.
tech-know.eu/uploads/Understanding_the_Atmosphere_Effect.pdf
“Thermodynamics says that no object in the universe can heat itself by its own radiation, nor can heat flow from cold to hot”.

RJ says:
March 30, 2011 at 3:13 am
DavidM
I’m just reading this article. This section below seems at variance to your very dubious Igloo example.
tech-know.eu/uploads/Understanding_the_Atmosphere_Effect.pdf
“Thermodynamics says that no object in the universe can heat itself by its own radiation, nor can heat flow from cold to hot”.>>>
NET heat cannot flow from cold to hot.
If it didn’t then you couldn’t stay warm inside of an igloo anymore than you could standing outside the igloo. Igloos work. Period.
Pour boiling hot coffee into a thermos at room temp. Which is hotter? The thermos of the coffee? The coffee obviously. Put a bowl out on the counter and fill it with an equal amount of the same coffee, cover it to prevent heat loss via convection. Wait six hours. Coffee in the thermos is still hot. Which is hotter? The coffee or the thermos? The coffee. What about the coffee in the bowl? Room temp. Huh.
So what heat source was it that kept the coffee hot? Given that it was in a thermos that was at a lower temperature than the coffee and there were no other heat sources being put into the thermos, why did it stay hot?
The answer is that it got some of its own heat back. It radiated heat to the thermos, which, as a consequence of warming up, radiated some back into the coffee.

davidmhoffer says:
March 30, 2011 at 2:11 am
As for bananabender….
If you’d actually taken Scouts 101 pretty much the first thing you learn is that any logs of a decent size simply will not burn well unless the burning faces are used to heat each other up. In your own example, if the pyramid of logs promoted surface area exposed to air, why wouldn’t the logs burn from the outside in instead of the inside out? If you took Scouts 201 you’d also know that arranging the logs in layers, each layer a set of parallel logs at right angles to the layer below, makes a fire that puts the pyramid to shame. It creates a whole series of surfaces radiating at each other to achieve much higher temps.
I was never a boy scout. That means I didn’t learn any of their incorrect explanations for how fires work.
A pyramid or a “log cabin” fire forms a venturi drawing fresh air in from outside the base like a chimney. Hot air rises via convection up the the inside of the structure. This causes the evaporation of volatiles which then ignite. The outside doesn’t burn well because wood is a very poor conductor of heat and there is very little direct heating from the flames.
In the case of a horizontal log the heat is carried upwards by convection so the wood below is not well heated. Charcoal is an exceptionally effective insulator so the wood below the flame doesn’t reach combustion temperature and the fire exhausts the fuel supply.
Radiation is a negligible contributor to flame propagation in small fires. Heat flow is always from hot to cold.

dp says:
March 29, 2011 at 11:28 pm
Multiple panes of glass work against conduction. They are useless against radiated heat unless they are designed (coated) to radiate IR back into the room in which case it is exactly the same as drawing the drapes closed but much more expensive.
Curtains reduce heat loss primarily by preventing convection currents near the window surface. This in turn reduces the effectiveness of the glass as a conductive heat exchanger. Curtains have very little effect on radiative heat loss. Triple glazing is far more effective at preventing heat loss than curtains in a cold climate
Triple glazed windows are effective primarily because they prevent conductive heat loss. Radiative heat loss across triple-glazed windows is low because glass is only partly transparent to IR radiation.
Pick up a good science book and don’t put it down until you understand how radiated energy works. Then teach your kids.
I’ve got three science degrees and have studied physics and chemistry at university. Unlike you I actually understand how radiation works.

Ira Glickstein says
…..” The effect of “Greenhouse” warming of the Earth is over 30ºC, which is many, many times the maximum possible temperature difference “…….
Looking at Ira’s CV perhaps he comes from an electrical engineering background.
Perhaps the degree options he picked did not include much thermodynamics.
However he has to be congratulated for his attempts to make a moving pictorial representation of the atmospheric radiative effects.
However these effects are greatly exaggerated such as the claimed 33K magnitude.
Ira consider this analogy from electrical engineering.
The suns effect on the earth surface as it spins resembles a half wave rectified AC signal (say after passing through a diode represents day/night) .
The earth has a great capacity to store the energy it receives from the sun.
This can be represented as three large capacitors connected in parallel.
The largest by far represents the oceans.
Another represents the atmosphere and a third represents the land surface say to a depth of two metres.
Completing the circuit is a resistor in which represents radiation to space.
Such a system would smooth out the day/night effect and would account for most of the 33K falsely attributed to the so called “greenhouse effect”.

Ira
Here’s one link
http://www.tech-know.eu/uploads/Understanding_the_Atmosphere_Effect.pdf
The section posted above is on pages 25 and 26
Or try this one to get to it
http://climaterealists.com/index.php?id=7457

bananabender;
I was never a boy scout. That means I didn’t learn any of their incorrect explanations for how fires work.>>>
You claimed the authority of Scouting 101 and now admit the credential was false. You also don’t appear to have much experience with building fires.
“A pyramid or a “log cabin” fire forms a venturi drawing fresh air in from outside the base like a chimney. Hot air rises via convection up the the inside of the structure. This causes the evaporation of volatiles which then ignite.”>>>
So….the fresh cool air streaming into the centre of the fire would cool it….convection through the “venturi” is exhausting hot air OUT of the fire…this process sounds like net heating to you? The volatiles evaporate DESPITE the net cooling of the convection process because the combined heat of the various surfaces radiating at each other is high enough to overcome the cooling via convection. Don’t believe me? Build yourself a decent sized fire and turn a fan or leaf blower on it to put 10 or 20 times the air through and around the hole thing than convection could. Watch what happens and report back.
“I’ve got three science degrees and have studied physics and chemistry at university. Unlike you I actually understand how radiation works.”>>>
Really? What are these science degrees you possess? Clearly not physics or chemistry since you only “studied” them, and you no more understand how radiation works than you do Scouting 101. Oh yeah, you didn’t have that credential either.

RJ says:

The average temperature of both the day and night hemispheres then comes out to +15 C, which is less than the input solar heating, not more.
It is not surprising therefore that in the first case, we need to theorize a greenhouse effect which ends up violating the laws of physics,

Bryan says:

Such a system would smooth out the day/night effect and would account for most of the 33K falsely attributed to the so called “greenhouse effect”.

Both of these comments are simply incorrect. The energy balance constraint on the surface temperature of the earth in the absence of an IR-absorbing atmosphere is that the fourth root of average of T^4 over the earth’s surface must be equal to ~255 K. If the temperature on the earth was uniform, this would mean that the average of T would also be 255 K. However, to the extent that temperatures are non-uniform over the earth’s surface, the average of T is actually less, not more, since there is an inequality where will always be less than the fourth root of (where denotes average). This inequality is one of the few things that Gerlich and Tscheuschner get right in their paper (although they misinterpret what it means).

RJ:

Here’s one link
http://www.tech-know.eu/uploads/Understanding_the_Atmosphere_Effect.pdf
The section posted above is on pages 25 and 26

So now the link works but we are left wondering what your point is. If it is that one can find a lot of nonsense out on the internet, I agree with you. If it is something else, then I would not use a paper that is so clearly nonsense to try to make your point!
Here’s a hint to you on where that paper goes wrong in all of its claims regarding thermodynamics and the greenhouse effect: The greenhouse effect does not say that (net) heat flows from hot to cold. (Some would say the word “net” is redundant since heat is usually a macroscopic concept describing the net energy flow.) In all models of the greenhouse effect, whether they are toy models or full-blown line-by-line convective-radiative transfer models, the heat flows from hot to cold.
The greenhouse effect is simply stating this: In the absence of an IR-absorbing atmosphere, all of the terrestrial radiation would be emitted directly out into space. However, in the presence of an IR-absorbing atmosphere, some of the terrestrial radiation is absorbed and when the atmosphere subsequently emits radiation, some of this radiation comes back to the earth. This keeps the earth warmer than it would be in the absence of the IR-absorbing atmosphere.
Also note that the Second Law of Thermodynamics is not magic: It does not state that colder objects magically detect the presence of a hotter object and refuse to emit any radiation towards said object. Rather, it is a statement derived from statistical physics that says that the amount of radiation that the colder object absorbs from the hotter will always be greater than the amount of radiation that the hotter object absorbs from the colder.

Joel Shore says:

However, to the extent that temperatures are non-uniform over the earth’s surface, the average of T is actually less, not more, since there is an inequality where will always be less than the fourth root of (where denotes average).

Whoops…I guess the HTML markup doesn’t do well with the brackets that I used to indicate averaging. That sentence should read:

However, to the extent that temperatures are non-uniform over the earth’s surface, the average of T is actually less, not more, since there is an inequality where the average of T will always be less than the fourth root of the average of T^4.

mkelly says:

The 340 average may infact be incorrect for TOA as my heat transfer book shows 1063 w/m^2 at 90 deg sun angle (over head at equator) for a surface W/m^2.

On average, the sun is not at a 90deg angle overhead. The average power in W/m^2 at the top of the atmosphere is obtained by considering the solar constant and the ratio of the area of a disc to the surface area of a sphere. Needless to say, these geometric formulas are on a pretty solid footing!

Is “back radiation” really required to explain the greenhouse effect? It seems to me that it just confuses the issue.
With a pure nitrogen atmosphere, almost all infrared radiation would pass through. The molecules of this atmosphere are primarily heated by direct contact with the surface of the sphere, and convection of this thin layer with the upper layers.
Now replace a mass of that nitrogen with a like mass of CO2. Now you have layers of the atmosphere (top to bottom) heated by infrared radiation that was previously not heating any portion of the atmosphere. The atmosphere is warmer – period. No need to talk about whether or not back radiation will heat up the surface or not, because it is obvious that the atmospheric blanket itself is warmer than it was before. (If you really want to make it warmer, exchange H2O for either of the other two gases.)
Do you feel warmer in a room with 15 degree air versus -15 degree air. Uh, yeah. But 15 degree air is below body temperature, so how could it possible be keeping you warm?! Well, neither is keeping you warm – that’s why you are cooling off. But you will cool at a slower rate in one versus the other.

Steve Keohane;
In my experience with bellows at a forge, very little, and at a fireplace, a lot, adding a stream of air increases the temperature of the flame. This can be seen as the fire without the air cannot melt a given metal, but with the stream of air it can. Varying the amount of airflow controls the temperature lower for forging, higher for melting.>>>
As with all real world examples, there’s no yes/no. In every situation, at every air flow, you get a curve and somewhere along that curve, yes, you can within a range on that curve control the heat of the fire. But at the far end of the curve, a large enough gust of air has the same result – fire goes out. Mini example – most people extinguish a match with a quick puff of air.
But getting back to your forge….thanks for yet another fine example. Could you bring metal to the melting point with the same amount of fuel in an open fire? No, of course not, if you could there’d be no need to build a forge. Lots of heat going out by convection alone, and then along comes you pumping that bellows to get the maximum temperature. So with all that heat being pumped by convection PLUS the bellows, which is WAY more than an open fire would lose, it is still WAY HOTTER inside the forge…
’cause the walls of the forge absorb heat from the fire, and as they heat up they radiate heat. Some away to the outside…and some right back into the fire. Which is why it is so much hotter in there than in an open fire.

RJ says:

We are playing into the alarmists hands if we accept the GHG theory as a fact.

It depends what your goal is. If your goal is just to sow confusion in the general public and hope that this helps keep policymakers from implementing the steps that you oppose, then you may be right…I don’t know. However, if your goal is to be scientifically-correct and to have an impact on the real scientific debate, then you are surely incorrect.
When I see people challenging the basic facts of the greenhouse effect, what it tells me is that they are either misguided or (if they are knowledgeable enough to know better) that they are trying to actively deceive people and confuse them on the science, i.e., their real goal has nothing to do with science and everything to do with pursuing their policy objectives at the expense of science.

Steve says:
March 30, 2011 at 1:07 pm
Is “back radiation” really required to explain the greenhouse effect? It seems to me that it just confuses the issue.
With a pure nitrogen atmosphere, almost all infrared radiation would pass through. The molecules of this atmosphere are primarily heated by direct contact with the surface of the sphere, and convection of this thin layer with the upper layers.
Now replace a mass of that nitrogen with a like mass of CO2. Now you have layers of the atmosphere (top to bottom) heated by infrared radiation that was previously not heating any portion of the atmosphere. The atmosphere is warmer – period. No need to talk about whether or not back radiation will heat up the surface or not, because it is obvious that the atmospheric blanket itself is warmer than it was before. (If you really want to make it warmer, exchange H2O for either of the other two gases.)
That’s a great point you raise.
But Steve, sorry, you are wrong. If ignoring the tiny radiation bands in nitrogen, the pure nitrogen atmosphere would over time be very, very hot. During the daytime with no clouds and oceans the atmosphere would heat greatly at the surface and disperse upward by conduction and convection as you said. As the Earth turns and night comes, all convection would ceases and the atmosphere cannot lose any heat by radiation as you said. Day by day the atmosphere would get hotter and hotter until the entire atmosphere would reach almost the same temperature as the daytime soil. The only cooling occurring would be by strictly conduction near the surface at night in contact with a frosty soil for it would be radiating unimpeded.
CO2 and all GHGs are a great fast conductors of heat. It is the over-half portion of radiation upward to space that keeps us from being literally cooked.

Probably already requested, but how about a page that has each graphic and each explanation below it? That way you can focus on the information in each graphic and not be distracted by the constant changing. Thank you.

Ira Glickstein, PhD says:
March 30, 2011 at 8:13 am
from Wikipedia
If an ideal thermally conductive blackbody was the same distance from the Sun as the Earth is, it would have a temperature of about 5.3 °C. However, since the Earth reflects about 30% (or 28%) of the incoming sunlight, the planet’s effective temperature (the temperature of a blackbody that would emit the same amount of radiation) is about −18 or −19 °C, about 33°C below the actual surface temperature of about 14 °C or 15 °C. The mechanism that produces this difference between the actual surface temperature and the effective temperature is due to the atmosphere and is known as the greenhouse effect.
While I certainly do not trust Wikipedia completely, since anyone may post almost anything to obscure topics, I know from personal experience that important scientific topics are monitored by domain experts who protect them from spurious information. Reed Coray, please cite a respected source for your “7ºC” estimate, and same for mkelly regarding your “15 C max”.
I believe the Wikipedia argument is correct. However, it compares apples to oranges. In particular, I’ll assume Wikipedia’s 30% number is correct. However, I then ask: “What part of the Earth reflects 30% of the sun’s energy?” From the papers I’ve read, it’s primarily the clouds and/or particulate matter in the atmosphere, not the surface of the Earth. When quantifying atmospheric effects on Earth surface temperature, shouldn’t you compare the measured Earth surface temperature (i.e., the temperature with an atmosphere) …to… an Earth model that is devoid of an atmosphere? Wikipedia’s model for the Earth surface temperature includes an atmosphere in that it’s the atmosphere that is reflecting 30% of the solar energy. So Wikipedia is comparing measured Earth surface temperatures to a model of Earth surface temperature that includes an atmosphere; and using the temperature difference to claim that the atmosphere raises the Earth surface temperature 33 °C . I call foul. It’s kind of like John Kerry saying he voted against it before he voted for it. (Sorry, I couldn’t resist).
An Earth without an atmosphere will have an albedo much nearer 0 than 0.3. However, assume for a moment that the albedo of an atmosphereless Earth is “x”. Then as I discussed previously, if you’re going to use Planck’s graybody radiation law to determine the rate energy is emitted from that surface, the surface emissivity must be the same as one minus the surface albedo. If true, for an atmosphereless Earth albedo of “x”, the emissivity of that atmosphereless Earth will be “(1-x).” The energy absorbed by the Earth from the sun is equal to the product of (a) the solar energy density (Watts per square meter) at the Earth’s surface, (b) the surface area of the Earth perpendicular to the direction of radiation (pi times the radius of the Earth squared), and (c) one minus the albedo–i.e., (1-x). The rate energy is radiated from the surface of the atmosphereless Earth will be the product of (a) the surface area of the Earth (4 times pi times the radius of the Earth squared), (b) the Stefan-Boltzmann constant, (c) the Earth surface temperature to the fourth power, and (d) the emissivity of the Earth–i.e., (1-x). For steady-state conditions, these two rates are equal. Since the factor “(1-x)” appears on both sides of the Equation, the temperature of an “atmosphereless” Earth is independent of the Earth’s surface albedo (one minus emissivity). Thus, the temperature of an atmosphereless Earth is the same as the temperature of a blackbody Earth–using Wikipedia’s value: 5.3 °C, not -18 ºC or -19 ºC.

wayne says:
March 30, 2011 at 2:44 pm
“But Steve, sorry, you are wrong. If ignoring the tiny radiation bands in nitrogen, the pure nitrogen atmosphere would over time be very, very hot. During the daytime with no clouds and oceans the atmosphere would heat greatly at the surface and disperse upward by conduction and convection as you said. As the Earth turns and night comes, all convection would ceases and the atmosphere cannot lose any heat by radiation as you said.”
I didn’t say that a nitrogen atmosphere cannot lose heat by radiation – is that what you are saying? I said that a nitrogen atmosphere would warm less than a CO2 atmosphere via the radiation emitted from a cooling earth surface. A molecule will radiate at wavelengths according to it’s emission spectrum, which is roughly equivalent to it’s absorption spectrum. Warming via conduction does not prevent cooling via radiation – the nitrogen in our atmosphere (most of the gas in it) cools every night. Are you proposing that the nitrogen gas in our atmosphere cannot cool off unless it collides with another type of atmospheric gas?

Reed –
On re-reading what you wrote, I realize that you didn’t assume a zero albedo for the earth as I said in my last post but you did assume, as Tim Folkerts points out, that the emissivity is the same in the visible as it is in the far IR…which is indeed not a very good assumption. Emissivities of the earth’s surface in the visible vary widely with the type of surface, whereas emissivities in the far IR tend to be very close to 1 for nearly all surfaces. (I believe I’ve read that the only place that there can be any significant deviations from 1 is in some desert regions.)

Tim Folkerts says:
March 30, 2011 at 4:09 pm
“Then as I discussed previously, if you’re going to use Planck’s graybody radiation law to determine the rate energy is emitted from that surface, the surface emissivity must be the same as one minus the surface albedo. ”
Not quite! The surface emissivity FOR VISIBLE LIGHT must be 1-albedo.
The surface albedo FOR IR must be 1.
There is no a priori reason the reflection for visible and IR must be the same
I agree. Real-world materials can exhibit emissivities (albedos) that are a function of frequency. For blackbodies, Planck’s radiation law contains a frequency dependent term of the form (f^3)*(df)/[e^(hf/kT) – 1]. When integrated over all frequencies (0 to infinity), the result is radiated power that is proportional to the fourth power of the temperature T. If to account for a different “visible light” emissivity and “IR” emissivity an additional frequency dependent factor g(f) is included in the law, then the integral over all frequency will only be proportional to the temperature to the fourth power if g(f) is constant. The T^4 rule may be a good approximation, but it won’t be theoretically correct. As such, if you’re going to compute the radiated energy using a temperature dependence of T^4, aren’t you implicitly assuming an emissivity (albedo) that is the same at all frequencies? If you’re going to use an emissivity that is a function of frequency, then shouldn’t you specify that dependence?
I’m curious. What do you believe is the primary source of solar reflection: (a) the surface of the Earth, or (b) the Earth’s atmosphere and matter in the atmosphere, or (c) something else? Do you agree or disagree that if you’re going to determine the effect of the atmosphere on Earth surface temperature by (a) treating the measured Earth surface temperature as the “Earth with atmosphere temperature”, and (b) using a model to compute the atmosphereless Earth surface temperature, the model should be entirely devoid of atmospheric effects?
If someone wanted to (a) model the position/frequency dependence of Earth surface absorption (no atmosphere) and the position/frequency dependence of Earth surface emission (no atmosphere), (b) compute the “average” Earth surface temperature using that model, and (c) argue that the effect of the Earth’s atmosphere is the difference between the average measured Earth surface temperature and the model average Earth surface temperature, I would have no objection. But that is not how the 33 degree number is computed. The 33 degree number is based on a reception albedo that, I believe, represents an “atmospheric albedo”, not an Earth surface albedo.

Nitrogen can’t radiate heat?
Since when? Everything above absolute zero radiates energy.
Atmospheric nitrogen has kinetic energy and therefore must radiate heat.
The atmosphere is heated by molecular-kinetic effects i.e. molecular collisions. Atmospheric temperature is a function of pressure and density not radiative effects.

davidmhoffer says:
March 30, 2011 at 9:39 am
bananabender;
So….the fresh cool air streaming into the centre of the fire would cool it….convection through the “venturi” is exhausting hot air OUT of the fire…this process sounds like net heating to you? The volatiles evaporate DESPITE the net cooling of the convection process because the combined heat of the various surfaces radiating at each other is high enough to overcome the cooling via convection. Don’t believe me? Build yourself a decent sized fire and turn a fan or leaf blower on it to put 10 or 20 times the air through and around the hole thing than convection could. Watch what happens and report back.
For every phenomenon there is a simple and elegant explanation that is totally and utterly wrong.
Your anecdotes are amusing folklore but they show absolutely no understanding of basic scientific principles.
Have you ever used a bunsen burner? You vary the flame temperature of this burner by altering the amount of air mixing with the gas. The more air you add the more completely the gas burns and the hotter the flames. Fanning a fire is exactly the same principle.
Air is an extremely poor heat conductor. The cooling effect of increased air flow into a fire is far less than the increased heat produced by more efficient combustion.
You can hold your finger 1cm from the side of a bunsen flame and not get burnt. Gases have almost no mass so they radiate very little energy. A bunsen transfers energy directly from the flame by conduction not radiation.
Really? What are these science degrees you possess? Clearly not physics or chemistry since you only “studied” them, and you no more understand how radiation works than you do Scouting 101. Oh yeah, you didn’t have that credential either.
I was employed as chemist in the food and beverage industries after I graduated from university. I regularly used various analytical spectroscopy methods including AAS, GC-MS, spectrophotometry, IR and near IR spectroscopy . Spectroscopy is based entirely on radiative physics.

wayne says:
March 30, 2011 at 6:09 pm
“Nitrogen, except for some small lines near 3 µm, cannot radiate at all.”
That determines the wavelengths at which it cools, it doesn’t limit the ability to cool off. It will still radiate according to it’s temperature. Nitrogen will radiate a lot of energy in a narrow band, instead of a moderate amount of energy across multiple bands.
“If all matter radiates, and an atmosphere of pure N2 radiates, then this is no different than what a GHG is portrayed to radiate in all directions and all atmospheres and all molecules always cause a “greenhouse effect”.”
The greenhouse effect is not a matter of the gases radiating, but absorbing. The surface of the earth radiates at a much larger variety of wavelengths than some gases can absorb, so some radiation goes directly to space without warming the atmosphere. If surface radiation is absorbed by an atmospheric molecule, it’s going to radiate that energy back out (within it’s emission spectrum), but not until it’s gained some vibrational/stretching/rotational energy in it’s bonds – it has to heat up to cool down.
bananabender says:
March 30, 2011 at 7:08 pm
“The atmosphere is heated by molecular-kinetic effects i.e. molecular collisions. Atmospheric temperature is a function of pressure and density not radiative effects.”
For convection to occur there must be a collision of masses. The vacuum of space doesn’t have enough mass for the upper atmosphere to collide with. The sun’s energy is radiated to the earth, and the earth radiates this energy back out into space as it cools.
Atmospheric pressure is a function of temperature. Of course our atmosphere (as do most) behaves as a near ideal gas. There is no fixed volume – it can only expand against the force of gravity. The outward force of temperature balanced by the downward force of gravity determines the pressure and volume. There is no volume constraint, so changes in temperature generate changes in pressure. Do you think that the night side of earth is exposed to a lower pressure from outer space, so the temperature goes down?

wayne says:
March 30, 2011 at 9:07 pm
“My interests of decades has been in astrophysics but I have never seen a definitive spectrum of purely nitrogen or argon or for pure hydrogen to indicate that those symmetric gases in our galaxy are opaque to IR.”
I think you misspoke there. Nitrogen gas is primarily transparent to IR, not opaque, just like it is primarily transparent to visible light. If nitrogen gas were primarily opaque to IR, imagine how difficult it would be to take a thermographic image in an atmosphere that is almost 80% nitrogen gas. It would be like trying to take a photograph in the fog.
“So, you could flip me back so easily if you could just show me a spectrum with lines or continuum ranges that are identified to be nitrogen or argon for that matter.”
In the infrared ranges? I can’t find those either, which is understandable. Typical infrared spectrometers use nitrogen gas as a purge for a very good reason – it doesn’t interfere with the readings. I have found a few articles, unfortunately behind paywalls, that reference it’s absorption/emission spectrum in the far infrared:
http://link.aip.org/link/doi/10.1063/1.431648
http://iopscience.iop.org/0022-3700/10/3/018
http://www.informaworld.com/smpp/content~db=all?content=10.1080/00268978400102221
“Why do think nitrogen gas is always radiating energy away in all directions?”
Because outer space is much colder than the temperature of the atmosphere, and nitrogen gas makes up almost 80% of the atmosphere. I feel it get cold at night, so the heat is going somewhere. Since it doesn’t get continuously hotter every day, the heat must be leaving the atmosphere, right?
You may be interested to read how satellite measurements pertaining to our temperature records are primarily readings in the microwave band, which correlates to heat radiated by oxygen gases (including ozone):
http://en.wikipedia.org/wiki/MSU_temperature_measurements

BigWaveDave says:
March 30, 2011 at 10:28 pm
Atmospheric pressure is a function of temperature. Of course our atmosphere (as do most) behaves as a near ideal gas. There is no fixed volume – it can only expand against the force of gravity. The outward force of temperature balanced by the downward force of gravity determines the pressure and volume. There is no volume constraint, so changes in temperature generate changes in pressure. Do you think that the night side of earth is exposed to a lower pressure from outer space, so the temperature goes down?
I will rephrase my comment. The atmosphere can be sufficiently heated by molecular kinetic effects without needy any radiation-absorbing “GHGs”. Radiative energy transfer only becomes more important than conduction and convection at the outer edge of the atmosphere.

Ira Glickstein,
Thank you for your efforts to bring out the science of one isolated aspect, which I call the earth’s ‘atmospheric effect theory’. It is one out of many interacting aspects of our earth’s atmosphere. I understand you are doing so when there are many aspects (including the one you are discussing) of our atmospheres which do interact and which are not isolated in the actual complex atmospheric dynamic.
The single isolated aspect (out of many interacting aspects) which you are presenting for discussion was purposely selected and isolated by you to aid in a clear presentation of just the one aspect that I call the earth’s ‘atmospheric effect theory’. I support your efforts to that extent with the understanding that what is not being presented by you is the total net effect (negative or positive) of the single isolated aspect you are discussing on the total complex earth dynamic system.
This latest post is much better, in my view, than the previous posts in your series that used analogy. It is best to just present the science rather than use analogy. Analogies are always limited and have some misleading attributes.
Things I find not at issue wrt the earth’s ‘atmospheric effect theory’ from the so-called consensus focused IPCC science:
a) The gases in our atmosphere interact by collision with each other and in doing so transfer energy.
b) Some of the gases in our atmosphere have the ability to absorb electromagnetic radiations of certain wavelengths. And in certain conditions re-emit it.
c) Some of the gases in our atmosphere have varying interaction with the incoming solar electromagnetic radiation and in doing some energy is transferred to some of the gases.
d) Some of the gases have varying interaction with the blackbody (or near blackbody type) radiation generated by all the surfaces of the earth and in doing so some energy is transferred to some of the gases.
e) Some of the gases have varying interaction with the blackbody (or near blackbody type) radiation generated by the atmospheric gases themselves and in doing so energy is transferred to some of the gases and also sometimes to the earth’s surface.
f) The electromagnetic radiation from the sun and also from the gases in our atmosphere has varying interaction with each of the earth’s various types of surfaces and in doing so some energy is transferred to the surfaces.
g) Some of the electromagnetic radiation from the earth’s surfaces go directly to space.
h) The electromagnetic radiation from all the gases in our atmosphere can, under certain conditions, go directly to space.
Things I find at issue wrt the earth’s ‘atmospheric effect theory’ from the so-called consensus focused IPCC science:
a) I would like to see the formal theory for what I call earth’s ‘atmospheric effect’. Show me the integrated formal theory. Has it been only premised that there is one, not shown that there is one? It cannot be uncoupled from other aspects of the climate system and remain meaningful.
b) I would like to see the actual comprehensive /unbiased /multiple /corroborating observations that demonstrate that a theory of earth’s ‘atmospheric effect’ has a significant net effect on meaningful climate parameters. OK, on average GST too.
Ira Glickstein,
John

Martin
Thanks for posting this.
What this GHG theory shows is how people will hold onto their beliefs no matter what. They are not acting as scientists should but hold onto their theory based on faith not science.
The killer for me is that logically the GHG theory does not stand up. It leads to absurd possible outcomes. Like for example heating the house with CO2 in the roof space. Or ice in a Igloo heating the body by backradiation.
Or an oven that heats a chicken without any outside power source.
http://www.slayingtheskydragon.com/en/blog/111-a-pictures-worth-a-1000-words
The GHG theory is flawed IMHO and its time to either move on or at least acknowledge the issues with this theory.

I said
Joel Shore’s simple world consists of an earth without oceans and a land surface that does not retain heat.
Joel replies
No…Retention of heat is not relevant to the considerations that I mentioned. The way that it comes into it is that the ocean helps to keep the temperature more uniform.
My reply;
The Oceans, covering 70% of planet surface, absorb solar radiation.
Some shorter wavelengths penetrate the water to a considerable depth.
In other words the effect is to increase the temperature of the water.
Ocean currents(and tides) distribute the hotter water.
E.g. the Gulf Stream effect keeps the west coast of UK much warmer than without it.
Glasgow is at the same latitude as Moscow.
The atmosphere, in particular clouds, help insulate the Earth surface.
The gross error of IPCC dogma is to attribute a 33K increase effect as due solely to the radiative properties of CO2 and H2O in gaseous form.
The early climate models did not even include clouds although some attempts are now being made to rectify this gross defect.