Guest post by Ira Glickstein
Albert Einstein was a great theoretical physicist, with all the requisite mathematical tools. However, he rejected purely mathematical abstraction and resorted to physical analogy for his most basic insights. For example, he imagined a man in a closed elevator being transported to space far from any external mass and then subjected to accelerating speeds. That man could not tell the difference between gravity on Earth and acceleration in space, thus, concluded Einstein, gravity and acceleration are equivalent, which is the cornerstone of his theory of relativity. Einstein never fully bought into the mainstream interpretation of quantum mechanics that he and others have called quantum weirdness and spooky action at a distance.
So, if some Watts Up With That? readers have trouble accepting the atmospheric “greenhouse” effect because of the lack of a good physical analogy, you are in fine company.
For example, in the discussion following Willis Eschenbach’s excellent People Living in Glass Planets, a commenter “PJP”, challenged the atmospheric “greenhouse” effect:
“The incoming energy (from the sun) you express in w/m^2, lets simplify it even more and say that energy is delivered in truckloads. Lets say we get 2 truckloads per hour. … when we come to your semi-transparent shell [representing greenhouse gases (GHG) in the atmosphere], you are still getting two truckloads per hour, but you say that these two truckloads are delivered to both the earth and to the shell — that makes 4 truckloads/hr. Where did the extra two truckloads come from?”
In that thread, I posted a comment with an analogy of truckloads of orange juice, representing short-wave radiation from Sun to Earth, and truckloads of blueberry juice, representing longwave radiation between Earth and the Atmosphere and back out to Space. A later commenter, “davidmhoffer” said “Ira, That was a brilliant explanation. …”
This Post is a further elaboration of my physical analogy, using a pitching machine and yellow and purple balls in place of the truckfulls of juice.
Graphic 1 shows the initial conditions. The Sun is a ball pitching machine that, when we turn it on, will throw a steady stream of yellow balls towards the tray of a weight scale, which represents the Earth. The reading on the scale is analogized to “temperature” and, with the Sun turned off, reads “0” arbitrary units.
TURN ON THE “SUN”
Graphic 2 shows what happens when the Sun is turned on and there are no GHG in the Atmosphere. The stream of yellow balls impact the tray atop the weight scale and compress the springs within the well-damped scale until equilibrium is reached. The scale reads “1”. This is analogous to the temperature the Earth would reach in the absence of GHG.
The balls bounce off the tray and, for illustrative purposes, turn purple in color. This is my way of showing that Sun radiative energy is mostly in the “shortwave” visible and near-visible region (about 0.3μ to 1μ) and that radiative energy from the warmed Earth is mostly in the “longwave” infrared region (about 6μ to 20μ). The Greek letter “μ” (mu) stands for a unit of length called the “micron” which is a millionth of a meter.
Since, at this stage of my physical analogy, there are no GHG in the Atmosphere, the purple balls go off into Space where they are not heard from again. You can assume the balls simply “bounce” off like reflected light in a mirror, but, in the actual case, the energy in the visible and near-visible light from the Sun is absorbed and warms the Earth and then the Earth emits infrared radiation out towards Space. Although “bounce” is different from “absorb and re-emit” the net effect is the same in terms of energy transfer.
If we assume the balls and traytop are perfectly elastic, and if the well-damped scale does not move once the springs are compressed and equilibrium is reached, there is no work done to the weight scale. Therefore, Energy IN = Energy OUT. The purple balls going out to Space have the same amount of energy as the yellow balls that impacted the Earth.
ADD GHG TO THE “ATMOSPHERE”
Graphic 3 shows what happens when we introduce GHG into the Atmosphere. The yellow balls, representing shortwave radiation from the Sun to which GHG are transparent, whiz right through and impact the weight scale and push it down as before.
However, the purple balls, representing longwave radiation from the Earth, are intercepted by the Atmosphere. In my simplified physical analogy, the Atmosphere splits each purple ball in two, re-emiting one half-ball back towards the Earth and the other half-ball out to Space. Again, you can assume that half of the balls “bounce” off the Atmosphere back to Earth like reflected light from a half-silvered mirror and the other half pass through out towards Space. In the actual case, it is “absorb and re-emit half in each direction” but the net effect is the same in terms of energy transfer.
OK, here is the part where you should pay close attention. The purple half-balls that are re-emitted by the Atmosphere towards Earth impact the tray of the weight scale and press against the springs with about half the force of the original yellow balls. So, at this stage, when equilibrium is reached, the well-damped scale reads “1.5” arbitrary units.
But, we are not done yet. The purple half-balls are absorbed by the Earth, and re-emitted towards Space. Then they are re-absorbed by the Atmosphere and once again split into quarter-balls, half of which head back down to Earth and re-impact the weight scale. Now it reads “1.75”. As you can see, the purple balls continue to get split into ever smaller balls as they bounce back and forth and half head out to Space. The net effect on the weight scale is the sum of 1 (from the yellow balls) + 1/2 + 1/4 + 1/8 + 1/16 and so on (from the purple balls). That expression has a limit of “2”, which is approximately what the scale will read when equilibrium is reached.
Again, the well-damped scale does not move once the springs are compressed and equilibrium is reached, so there is no work done to the weight scale. Therefore, Energy IN = Energy OUT. The purple balls going out to Space have the same amount of energy as the yellow balls that impacted the Earth. But the “temperature” of the Earth, as analogized by the reading on the weight scale, has increased.
DOUBLE THE GHG IN THE “ATMOSPHERE”
Graphic 4 is the final step in my physical analogy. Let us double the GHG in the Atmosphere. (NOTE: I am assuming that the doubling includes ALL the GHG, most especially water vapor, and not simply CO2!) This is represented by putting a second layer of Atmosphere into the physical analogy.
The purple balls emitted towards Space by the first layer of the Atmosphere are intercepted by the second layer, where they are absorbed, and smaller balls are re-emited in each direction. The downward heading balls from the upper atmosphere are intercepted by the lower Atmosphere and half is re-emitted down towards the weight scale that represents Earth. Once again, they compress the springs in the weight scale increasing the reading a bit, and are re-emitted back up. The purple balls get halved and bounce around up and down between Earth and the two layers of the Atmosphere, further increasing the reading on the scale once equilibrium is reached.
Again, the well-damped scale does not move once the springs are compressed and equilibrium is reached, so there is no work done to the weight scale. Therefore, Energy IN = Energy OUT. The purple balls going out to Space have the same amount of energy as the yellow balls that impacted the Earth. But the “temperature” of the Earth, as analogized by the reading on the weight scale, has increased due to the doubling of GHG in the Atmosphere.
WHAT I LEFT OUT OF THE PHYSICAL ANALOGY
Any simplified analogy is, by its very nature, much less than the very complex situation it is meant to analogize. Here is some of what is left out:
- My purple balls are re-emitted in only two directions, either up or down. In the real world, longwave radiation is emitted in all directions, including sideways.
- My purple balls are all totally absorbed by the Atmosphere and re-emitted. In the real-world, a substantial amount of longwave radiation is re-emitted from the Earth and the Atmosphere in the 9μ to 12μ band where the Atmosphere is nearly-transparent. A substantial portion of the radiation from Earth and the Atmosphere thus passes through the Atmosphere to Space without interception.
- My physical analogy addresses only radiative energy transfer. In the real-world, energy transfer from the Sun to Earth and Earth to Space is purely radiative. However, the Earth transfers a considerable amount of energy to the Atmosphere via convection and conduction, in the form of winds, precipitation, thunderstorms, etc. These effects are absent from my analogy.
- I represent the Atmosphere as a single shell, when, in fact, it has many layers with lots of interaction between layers.
- I represent doubling of GHG as adding another shell, when, in fact, doubling of GHG, if it occured (and if it included not just CO2 but also a doubling of water vapor and other GHG) would increase the density of those gases in the Atmosphere and not necessarily increase its height significantly.
- In my analogy, all the energy from the Sun strikes and is absorbed by the Earth. In the real-world, up to a third of it is reflected back to Space from light-colored surfaces (albedo) such as snow, ice, clouds, and the white roof of Energy Secretary Chu’s home :^). If a moderately warmer Earth, due to increased GHG, evaporates more water vapor into the atmosphere, and if that causes more clouds to form, that could increase the Earth’s albedo to counteract a substantial portion of the additional warming.
I am sure WUWT readers will find other issues with my physical analogy. However, the point of this posting is to convince those WUWT readers, who, like Einstein, need a physical analogy before they will accept any mathematical abstraction, that the atmospheric “greenhouse” effect is indeed real, even though estimates of climate sensitivity to doubling of CO2 are most likely way over-estimated by the official climate Team. When I was an Electrical Engineering undergrad, I earned a well-deserved “D” in Fields and Waves because I could not create a physical analogy in my overly-anal mind of Maxwell’s equations or picture the “curl” or any of the other esoteric stuff in that course. Therefore, those WUWT readers who need a physical analogy are in great company – Einstein and Glickstein :^).
I plan to make additional postings in this series, addressing some implications of the 9μ to 12μ portion of the longwave radiation band where the Atmosphere is nearly-transparent, as well as other atmospheric “greenhouse” issues. I look forward to your comments!
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Comparing WUWT readers to Einstein because of something they typically fail to understand, is ridiculous.
davidmhoffer says: February 21, 2011 at 10:57 am
You keep misquoting me. A lot of anger bubbling in there, davidmhoffer. Anger that is stopping you reading what I wrote:
‘You went from it is SO simple to it would take thousands of words’. No I didn’t. I said it would take thousands of words to deconstruct Ira Glickstein PhD’s analogy. The analogy is so wrong (as a number of other commentators have pointed out) that there is really no point in wasting more time on its details.
I have already told you I that I used some shorthand to save some space.
‘…comments don’t disappear from view for presenting contrary views of science’. I wrote ‘disappear out of view’ – there is a difference. At the time I write this there are 171 comments. Do you think anyone would thank me for writing in the middle of all that a description of the greenhouse effect so long that even you could understand it? No, Ira Glickstein PhD put his baloney up in the first place, it’s not my job to rewrite it.
I didn’t realize that I was presenting ‘contrary views of science’. The two points in my previous post 1) CO2 is a GHG and 2) GHG’s absorb longwave IR are incontestable, unless, that is, you believe the moon is made of green cheese and grassy knolls.
I happen to be strongly skeptical when it comes AGW. Which is why it annoys me that the guys at RealClimate will be laughing their heads off when WUWT posts something as flat wrong as Ira Glickstein PhD’s rubber ball and kitchen scale analogy. It doesn’t work on any level.
Dennis Wingo says (February 21, 2011 at 6:00 am): “Ira, I have to take issue with this explanation. A greenhouse works because when light comes through the glass of the structure, it is shifted to longer wavelengths that can no longer penetrate the glass.”
(1) Try opening a window in the greenhouse; does the greenhouse temperature drop because infrared light escapes through the opening, or because colder outside air is entering and warmer inside air is escaping?
(2) Build a seond, identical greenhouse using material transparent to infrared light. Is the second greenhouse warmer, colder, or pretty much the same temperature as the first?
davidmhoffer says: February 21, 2011 at 11:27 am
RichardSmith: ‘Hmm. So in Bangkok at night you can hold your hand up and feel all the warmth coming from the clouds?’
davidmhoffer: ‘In that single, sarcastic question, you just announced to every single reader with a basic knowledge of radiative physics that you do not have a single clue what you are talking about. You shoot your mouth off about how wrong other people are, won’t provide an explanation of your own on flimsy excuses, and then ask a question like that.’
Blograge! I knew you’d like that question…
HenryP says:
February 21, 2011 at 11:21 am
Also, oxygen is a weak greenhouse gas as it also has a very weak absorption in the 14-15 um range.
It doesn’t, see here:
http://i302.photobucket.com/albums/nn107/Sprintstar400/CO2N2O2.png
Sigh. Discussions with real life (meatspace) warmists never reach this depth. They don’t even know that the CO2 GHG effect is expected to be logarithmic (No, not one of the people i know).
Yet they expect me and everybody else to pay for their economically harmful green energy schemes (and they don’t understand that economically wasteful endevours are also wasting resources). Must find ways to exploit them more…
The imposition of a second layer of GHG is not what would occur in real life. A doubling of the GHG layer would merely make the initial layer shown in fig.2 be twice as thick, which would not change the “splitting” of the energy at all, meaning that fig.2 is the only working model.
Additionally, the imposition of the second layer is above the first layer. Why this arbitary location? If the second layer is located below the first layer, then the overall amount of “ball energy” hitting the earth is reduced.
Adding the second layer complicates the entire scenario and depending where it is arbitarily placed then the result is either less or more energy hitting the earth. This should show that the logic of a second layer is incorrect.
Consequently I believe that the third figure is not correct and the overall analogy should have stopped at Figure 2. This would imply that the amount of GHG is irrelevant as there is an upper limit on the impact on temperature, which is what I understand actually theoretically occurs.
(Long time reader, but first time poster)
Thanks, Ira. I figured something like that, but in all honesty, I’m getting more confused by the moment. The arguments against GHG having any effect seem pretty good, as do the arguments that it has an effect. To quote “Vinnie” Barbarino, “I’m so confuuused.”
However, when it comes to science, that’s a good thing. It puts the brakes on orthodoxy.
Now I’m off to build two greenhouses and fill one with CO2.
I never understood, how and why most of the models and explanations of the “greenhouse effect” don’t even touch upon the most fundamental fact — namely, that a very substantial portion of CO2 present in the atmosphere at any given time is absorbed by the plants, and chemically transformed into sugars, other carbon compounds, and oxygen, therefore removing the alleged “greenhouse gas” from the circulation (even if the “greenhouse” analogy could be used to explain, what is going on in the atmosphere physically, which is unlikely — for the simple reason, with very complex consequences, that the Earth’s atmosphere is NOT a greenhouse by any measure or analogy).
Moreover, the higher the concentration of CO2 in the atmosphere, the faster plants grow, and the larger is the volume of CO2 being absorbed and transformed.
Moreover, any discussion of the published CO2 data is meaningless without mentioning that these figures are obtained downwind from the active volcano, in the vicinity of the volcano.
Moreover, it has been mathematically and physically proved, several times, by many respected scientists, that CO2 ceases to act as the reflector of heat (infrared radiation) at concentrations above approximately 300 ppm.
The whole “greenhouse” analogy doesn’t hold water.
Alan and Gary,
I should have said “radiative heat transfer” rather than radiation.
You are wrong here: The atoms do know what direction the radiation comes from. It has momentum.
You are correct here: When electrons (or other qm potential energy) spontaneously drop in their energy levels, the EMR follows a random direction. This EMR is unbounded by time, and is a form of communication with the object receiving it. If it is directed from your body back to your coat, then the electron in your coat will absorb it, knowing the direction and the source. Momentum is conserved. This only will work if the electromagnetic radiation has a source and a receiver. The reverse process also occurs. In this you are correct.
That is not what I am having a quibble about. People keep claiming that heat is transferred from the CO2 back to the ground. No, it is not. It can’t if the ground is warmer that the CO2.
As for your coat analogy, the heat being transmitted from your body to the surroundings with not coat is proportional to the temperature difference of your body to the surroundings to the 4th power.
If you put on a coat, your body is now radiating heat to your coat, which is warmer than the surroundings. (you are also primarily conducting heat, way more than you are radiating, and the coat is an insulator, but this is not what Gary was talking about). The heat transfer from your body to your coat by radiation is always in that direction (as is the conduction). This heat transfer is slower than it would be to the surroundings because of the smaller temperature difference. This is why you are warmer. You are losing less heat. It is not because the coat is actively warming you.
Also, our statements are mathematically equivalent. Again, radiative heat transfer ONLY occurs in the direction from a hot source to a cold source.
How do we know where the molecules are going? Do they give us advance notice?
Better to be silent and thought stupid, then to speak and remove all doubt.
M. Twain
@izen
I know that it is measured at different places but the data is not the same.
Example(same time different location):
Park Falls, Wisconsin, United State: ~390ppm
Ascension Island, United Kingdom: ~ 383ppm
Baltic Sea, Poland: ~ 405ppm
The Aircraft Profiles also shows also that it varies in the first 8KM more or less depending on the season. http://www.esrl.noaa.gov
Above 10km molecules and atoms tend to separate, with the heavier gases beneath the lighter ones, in a layer called the heterosphere.
Sadly all these thought experiments fail on the issue of there being no photons until there is an interaction. That interaction could be with other wavefronts coming up from the surface or with other CO2 particles… It should also be noted that most of the IR is from water vapor and not CO2 except in a very few very dry areas of the earth. In those dry areas the atmospheric window is much larger. Like Venus, CO2 on earth only provides a couple of narrow slats to cover the full emission window.
This type of thought experiment only tends to cement a FALSE idea of what is actually happening with the result of an increased magnitude of warming more easily accepted.
AJB
Sorry for the slow reply. Eventually, the only way to lose energy to outer space is radiation.
What you say is true. I, like Dr. Glickstein, was trying to give a simple answer to a question.
The question I was answering was this: “…. Cold rarefied gases measurably increase the earth’s surface temperature? No, sorry, I don’t buy it. ” I think my answer deals correctly with that question.
What you say about heat transport by evaporation, condensation and convection is true. As far as I can tell, the vast majority of heat is removed from the equatorial ocean and lower atmosphere by evaporation, transport and convection. However, the only way the earth can lose heat to outer space is by radiation.
No, a simplistic application of radiative physics does not apply. But, yes, eventually radiation rules. The mechanism just isn’t really simple. 😉
Well I would have one immediate criticism of your gold and purple ball diagram; although I like some aspects of it.
WHY !! ?? do ALL of the gold balls go right on by the atmosphere as if it wasn’t there. For a start, we know that a goodly fraction of the gold balls, which are actually a bluish shade of gold, are Raleigh scattered by the atmosphere, and split into two streams just like your blueberries. No they aren’t absorbed by the atmosphere, so don’t really change the atmospheric Temperature; but still the atmosphere splits them into two equal streams; up and down.
Then there are also some red and black balls in the gold mix, that DO get absorbed by the atmosphere, just like your blueberries, and they too contribute to the atmospheric Temperature; and from there they are quite indistinguishable from the blueberries; even though the atmospheric absorption mechanism is different (in detail) from your surface originated stream.
I also think the concept of a second layer of GHG due to “a doubling” is not a good analog. I prefer an infinity of very thin layers; each of which captures a certain amount of energy from either gold or red/black balls.
I think it is a mistake to think of some layer thickness that basically “saturates” its CO2 band. So a micron thick layer is possibly saturated; and what it captures warms that layer which them emits a thermal spectrum (of blueberries up and down).
The sparseness of that layer, is accounted for in the spectral or total emissivity of the layer. So a thin layer at 288 K is emitting 390 W/m^2 times epsilon, both up and down. It then becomes clear that gases are no different from liquids or solids in their emission of a thermal radiation continuum, that is a function only of the Temperature. The solids and liquids, just get to near a 1.0 emissivity, in a much thinner layer.
A gold metal layer beaten out to a 100 Angstrom thick film, is also not going to radiate like a solid; it is going to start looking decidedly more gas like, because of its extremely low thermal mass, so that a small radiation can result in a large Temperature drop (unless replenished from some continuous energy source).
Which brings me to another issue.
A lot of people toss out “Kirchoff’s Law” as requiring that something that absorbs such and such spectrum energy must also emit the same. So they claim that nitorgen and oxygen don’t absorb IR, so they don’t emit IR either. This forces them to invent a two step process, whereby CO2 (or other GHG) absorbs some LWIR radiation, and then thermalizes it by collision with the other molecules, and then sometime later, a warmed over N2 molecule clobbers the CO2 again, and re-energises it so it can now emit the specific CO2 spectral band of radiation that it started with. And that is how they see the atmosphere radiating LWIR. It can therefore only be emitting the CO2 specific LWIR band; say 13.5 to 16.5 microns. Why not the 4 micron band also?
So this is a consequence of Kirchoff’s law.
Well the problem is that Kirchoff’s Law applies ONLY in a state of equilibrium. It doesn NOT apply to a steady state condition; and the earth atmopshere absolutely never ever has been in any state of equilibrium. It is constantly exchanging energy with its surroundings; there’s a contunuous (in daylight) input of solar energy, and a continuous 24 hours input of LWIR thermal continuum radiation.
Kirchoff’s law does not apply to this condition; so the general inability of N2 or O2 and Ar to absorb much in the way of LWIR radiation, in no way prohibits the same gases from emitting a thermal spectrum just based on the Temperature.
Notice that so far as I am aware; there are precisely three Physical Constants that are defined as having absolutely accurate known values; with no error bars.
Those are (c) and (epsilon naught) and (mu naught), the permittivity, and permeability of free space; which together yield (c) as 1/sqrt(mu-naught times epsilon naught). That result is a direct consequence of Maxwell’s equations for the electromagnetic field.
So Maxwell did not get banished to oblivion by the quantum theory. The Bohr atom which arbitrarily declared that just for the hell of it, an electron in a “preferred” orbit of the Bohr model, would not be allowed to radiate, unless it jumped from that orbit to another. A completely unjustified piece of nonsense. Well I suppose a lawyer type might say that that refers to something that is “not in evidence”.
Well we shouoldn’t be too hard on Nils Bohr, it was an ingenious step around a thorny roadblock, but one that immediately led to a whole lot of “aha” understanding of atomic structure.
Well the de Broglie and Schrodinger Wave mechanics got back to common sense by establishing a different concept for the electron orbitals, as simply being places with a certain map of probablility of finding the electron somewhere there. Well you see that now the electron does not have to go whizzing around in some Bohr Sommerfeld eliptical planet like orbit on Bohr’s say so that it wouldn’t radiate. Radiate ! I’m not even moving; why should I radiate. How easy is that ? Maxwell is resuscitated, and we can forget that Bohr’s overstepping reality got us back to sanity eventually. Well no we shouldn’t forget it; it was the work of pure genius to see us all comfortably through an amazing time in physics. I wasn’t there to witness it all ;but I do admit to having been in on the discovery of the neutron , by Chadwick. Well I was a bit busy doing other things to attend those lectures; but I was around at the time.
Well the upshot of all of this, is that Maxwell’s explanation of EM radiation from accelerated electric charges, as the origin of thermal radiation from anything that is above absolute zero, including gases, is quite sound. I’m sure there is a quantum explanation as well; but everytime a molecular collision occurs in the atmosphere; both molecules undergo accelerations along with the electric charges thay contain; so there is plenty of bumping going on to emit thermal radaition.
But it is NOT an aequilibrium process, so don’t expect Kirchoff’s law to apply.
Ira
Ira Glickstein at February 20, 20111 at 7:24 when commenting upon a post by Ken Coffman February 20, 2011 at 5:15 pm, says:-
Sorry Ken, but, although the nighttime Earth is cooler than it is in daytime, it remains warm enough to continue emitting longwave radiation. If not for the GHGs in the atmosphere (not just CO2 but also water vapor and other GHGs) it would be a heck of a lot cooler at night and, over the entire day and year, the Earth would be too cold to support life. Those are the facts. Please do not allow the distortions of the facts about CO2 sensitivity and the temperature record by the official climate Team lead to an equal and opposite reaction in the wrong direction.
///////////////////////////////////////////////////////////////////
Whilst your post deals with the role played by greenhouse gases in general, and one example depicts the effect of a doubling of ALL greenhouse gases, Ken’s comments are directed at looking at the role played by CO2. As we all know, the debate underpinning AGW is what role does CO2 have and what is the effect of doubling this particular gas?
I have yet to meet a sceptic who challenges the assertion that a CO2 molecule has the ability to absorb LWR and to re-radiate that absorbed energy. However, the issue is not how a CO2 molecule in isolation may behave but rather how it behaves in practice in the real world environment to which it is a part. The manner in which CO2 behaves in the real life environment of the Earth’s atmosphere (including the manner in which the Earth receives its energy from the sun during days, during seasons) may mean that sensitivity is zero, or close to zero, or at any rate insignificantly small. The problem is that presently, there has been no real life experiment measuring this.
There are many reasons to suspect that CO2 in the real world has little greenhouse effect, for example, it may be that CO2’s power of absorption is largely cancelled out by its power of emission, it may be that due to the time required to radiate energy the majority of CO2 molecules have already by way of collsion/thermalisation lost the LWR energy that they had previously absorbed (when radiated from the Earth’s surface), the fact that Mars notwithstanding a rich CO2 atmosphere (admittedly of little density) does not appear to possess an enhansed temperature above its theoretical blackbody temperature (in fact some calculations suggest that its observed temperature is ever so slightly less than its theoretical blackbody temperature), etc. Further, air has little heat capacity and the wavelength of re-radiated radiation from CO2 is such that it cannot effectively penetrate the oceans (depth of penetration about 10 microns) and at most it simply boils off a small layer of the ocean which probably has a net cooling effect.
Sometimes, nature allows us to view a real life experiment. Occassionally, we get a glimpse at the real life effect of CO2 and how it operates when water vapour is removed from the equation. E.M. Smith posted an example (Frostbite Falls – 23rd January 2011) in which he looks at a record low set at International Falls on Friday 21st January 2011. That night was a low humidity, clear, still night. The clear skies meant that there were no clouds to blanket IR radiation. The fact that it was still meant that there was little turbulence or convection processes ongoing. The fact that it was low humidity meant that there was little water vapour in the air to act as a greenhouse gas. From a greenhouse perspective, we were left with a glimpse at what CO2 could achieve, ie., how much it brings to the table. The answer to the experiment was bug*er all. That night set a record low of -46 degC (ie., 227 deg K) which is below the blackbody temp of the Earth. This was notwithstanding approximately 390 ppm of CO2 in the atmosphere doing its best to heat the Earth below.
Of course, the weather had been cold for some time. On Wednesday it the high had been – 9 deg C, on Saturday, the high only managed -22 deg C. One can see from this when CO2 is left as being the only greenhouse gas (in practice it was not completely alone), it cannot prevent a drop off in temperature of up to 35 or so degrees. It is clear from this that the residency time of the CO2 ‘trapped’ IR is of short duration and when only CO2 is at work, in the real world, it provides little in the way of insulation/warming. I therefore consider it unlikely that if CO2 was significantly reduced “…it would be a heck of a lot cooler at night.” I consider that real life experience demonstartes that statement to be conjecture and unsupported and almost certainly wrong.
What keeps us warm during the night is the oceans and water vapour and clouds. It is likely that in the real world environment CO2 adds little to this and effectively contributes next to zilch.
The crux is the point made by AJB at February 20, 2011 at 10:16 pm:
“Until someone shows me otherwise, I maintain water rules the thermosphere – it’s a heat pump running at half throttle with a hunting governor (clouds) and a massive heat sink under it.” I fully concur with that.
Finally, whilst I have enjoyed reading your post (and others made by you) and not wishing to be rude, I would observe that what we need in this debate is not some physical analogy but rather some real observational atmosheric empirical data depicting the characteristics which CO2 is claimed to possess and produce.
There is one more fact that is being conveniently ignored in most discussions of the “greenhouse effect” and Earth’s thermal balance:
Large portion of the sunlight radiative energy reaching Earth is being absorbed by the plants and stored as chemical energy in organic compounds. When we release energy by burning coal, we release sunlight energy stored by the plants millions of years ago.
Where is this simple fact in “greenhouse effect” models?
Earth is not a black body. It is not a green house. It is a gigantic bio-technical solar panel exchanging heat with eternally moving and swirling air masses and oceanic currents while transforming Sun’s energy into the organically stored chemical energy, thus cooling itself and maintaining the thermal balance within a very wide range of changing variables such as insolation, atmospheric content of various gases, their vertical and geographic distribution, volcanic activity, cosmic radiation, magnetic phenomena, and thousands of other important factors not taken into account by using Boltzmann’s formula.
It doesn’t make sense to talk about “greenhouse effect” at all.
WOW, just WOW, a scale (including by the author’s own admission; springs and damping) to explain the absorption and reemission of electromagnetic radiation. I’m just shaking my head.
With respect, once the springs in the scale are compressed, “absorb the force from the ball” and have “reached equilibrium, thereby no further work is done” what pray tell causes the balls to be reemitted towards space?
Perhaps a better sequence would be:
A photon (visible) is absorbed and thereby ceases to exist
The temperature of the Earth rises (scale = +1)
A photon (IR) is emitted
The temperature of the Earth falls (scale = 0)
Somewhat less than ½ of the IR photon returns, the Earth warms (scale = +~1/2), A photon (IR) is emitted, the Earth cools (scale = 0)
Only if the photon can travel from Earth to the gases and back faster than the Earth can cool can your scale possibly show anything higher than zero after each sequence.
But of course we know that the Earth already cooled back to zero when the photon left the first time.
From a thermodynamic sense your scale has broken the laws, it cannot absorb, retain and also emit the same packet/quantum/photon of energy.
Cheers, Kevin.
“”””” Fred Souder says:
February 21, 2011 at 3:02 pm
Alan and Gary,
I should have said “radiative heat transfer” rather than radiation.
You are wrong here: The atoms do know what direction the radiation comes from. It has momentum. “””””
Well there is no such thing as “radiative heat transfer”, although people do use that term loosely, and quite incorrectly.
For a start “Heat” is a verb, and describes the process of storing energy in the kinetic motion of actual real physical matter; Ie atoms and molecules. Photons do NOT sore “heat energy”.
To the extent that once uses “heat” as a noun, it relates only to that mechanical energy of the motion of molecules, that are not at the absolute zero of Temperature. And we know the amount of that energy from the equipartition principle, that the average kinetic energy should be kT/2 for each degree of freedom for mechanical motion. since there are three translational axes, then we at least expect 3kT/2 for even a monatomic molecule like Argon. there can also be rotational modes that provide for even more energy storage; but the whole concept of “Tempertaure” and “heat (energy) are inextricably lionked by that nkT/2 relationship.
Photons on the other hand don’t have any understanding of Temperature whatsoever; they are a consequence of Maxwell’s equations for the Electromagnetic field, which also has NO Temperature input or knowledge.
And photons can go anywhere they please. photons emitted from the surface at Vostok Station while the Temeprature is close to -90 deg C, can propagate out into space (if they are lucky) and reach the back side of the moon, which is even colder than Vostok Station. Those very same photons at a different time, can miss the moon completely but proceed, covering the same 1/2 degree angular subtense until 93 million mile later they can reach the surface of the sun at about 6, 000 Kelvins.
They will land there and be received just as happily as they would be on the cold moon surface.
Electromagnetic radiation conveys radiant energy, in a manner that can be calculated from Maxwell’s equations (from the square of the electric field vector), or it can be represented by the h(nu) photon energy of quantum mechanics.
This constant insistence on applying thermodynamic principles or concepts, to systems that are NOT thermodynamic in nature; is part of what keeps “skeptics” branded as “ignorant fools”.
It’s not that more accurate information isn’t available; but there is continuous gaggle of folks who for one reason or another won’t take the time to learn a few basic concepts. You don’t have to know Quantum Chromo-Dynamics at your fingertips to understand the basic energy processes of weather and climate; and there are processes with thermodynamic properties and consequences, and also processes without thermodynamic consequences; such as EM radiation.
“”””” Phil. says:
February 21, 2011 at 1:07 pm
HenryP says:
February 21, 2011 at 11:21 am
Also, oxygen is a weak greenhouse gas as it also has a very weak absorption in the 14-15 um range.
It doesn’t, see here:
http://i302.photobucket.com/albums/nn107/Sprintstar400/CO2N2O2.png “””””
Thanks for the very nice composite spectrum Phil. Can you describe what the assumptions are for these spectracalc computations. Are they computing some kind of intrinsic line width, for each different mode; or what are the presumed physical conditions of the sample. Does spectracalc allow one to determine broadened spectra from ambient Temperature (Doppler) and Collision (density) broadening ?
I get frustrated; when I see some CO2 or other “spectrum” and they say it was calculated to be at such and such wavenumber; but is observed somewhere else. That does not instill a lot of confidence in the calculation model.
I preume with what Astronomers dig up from their outer space laboratory; that we are somewhat better at the computation of a molecular spectrum than would deviate by 20% or more from some actual physical measured spectrum.
Unfortunately I do not have an open access to spectracalc; so thanks for posting such an informative plot.
commieBob says: February 21, 2011 at 4:09 pm
Thanks Bob. Of course radiation must eventually rule but the essence is in the detail. There is a lot going on above the tropopause that never seems to get much mention. Of late we’ve seen the business of the stratosphere becoming wetter, changing incidence of noctilucent clouds, thermosphere expansion/shrinkage, etc. (not to mention the mesopause anomaly, ionization, ozone, sprites, blue jets, and so on).
It would be really great if someone would put all this together and at least paint the bigger picture here on WUWT. What, for example, is the CO2 concentration trend in these regions and why is increased CO2 in the mesosphere reckoned to produce net cooling which isn’t AFAIK being observed? Any volunteers 🙂
Alexander Feht says:
February 21, 2011 at 2:50 pm
I never understood, how and why most of the models and explanations of the “greenhouse effect” don’t even touch upon the most fundamental fact — namely, that a very substantial portion of CO2 present in the atmosphere at any given time is absorbed by the plants, and chemically transformed into sugars, other carbon compounds, and oxygen, therefore removing the alleged “greenhouse gas” from the circulation (even if the “greenhouse” analogy could be used to explain, what is going on in the atmosphere physically, which is unlikely — for the simple reason, with very complex consequences, that the Earth’s atmosphere is NOT a greenhouse by any measure or analogy).
Only approximately half of the fossil fuel generated CO2 is sequestered each year, hence the annual increase in CO2 concentration in the atmosphere.
Moreover, the higher the concentration of CO2 in the atmosphere, the faster plants grow, and the larger is the volume of CO2 being absorbed and transformed.
The proportion sequestered remains fairly constant.
Moreover, any discussion of the published CO2 data is meaningless without mentioning that these figures are obtained downwind from the active volcano, in the vicinity of the volcano.
They aren’t.
Moreover, it has been mathematically and physically proved, several times, by many respected scientists, that CO2 ceases to act as the reflector of heat (infrared radiation) at concentrations above approximately 300 ppm.
Aside from the fact that CO2 doesn’t reflect IR no ‘respected scientist’ has proved anything of the sort, and it isn’t remotely close to being true.
The whole “greenhouse” analogy doesn’t hold water.
From your remarks above you don’t appear to know what the ‘greenhouse analogy’ is.
Stephen Fox, looks like you are the one!
Thought Ira might be the one to follow what I was trying to making so visual for him to follow step by step and to grow a bit in his view of radiative transfer within a real atmosphere but you seem to be the only one to grasp it. He really should read Miskolczi’s paper fror an astrophysicists viewpoint (two or three times).
Thanks for the mention.
My day this Monday turned out to be doublely good! ☺
Fred Souder says (February 21, 2011 at 3:02 pm): ” Again, radiative heat transfer ONLY occurs in the direction from a hot source to a cold source.”
Change that to net radiative transfer and I think just about everyone here would agree.
As written, however, the statement is incorrect.
George Smith,
Yes, there is such a thing as radiative heat transfer. Just like convective heat transfer, and like conductive heat transfer. It is not a term used loosely. It is what heats up Earth. It can be calculated. I am not getting why you say that it doesn’t exist. I understand everything else you wrote in your brief explanation of electromagnetic waves. Maybe I am using the vocabulary loosely?