Home/Blog
I continue to receive a steady stream of comments and e-mails which challenge my views on how the climate system operates. And that’s fine.
But I also seem to get the same questions, over and over. I understand that it is time consuming to wade through all of the blog posts to find the ones where I address certain issues, so from time to time it seems useful to explain (once again) my understanding of things.
So, here’s my latest attempt at explaining temperature change, the “greenhouse effect” (yes, I know it’s not like a real greenhouse, but thanks for the tip), and why alternative theories cannot yet replace greenhouse theory.
Temperature is the Result of Energy Gain AND Energy Loss
The temperature of something (the Earth’s surface, an atmospheric layer, the human body, a pot of water on the stove) is related to rates of energy gain and energy loss. Thus, generally speaking, you can increase temperature in one of two ways: (1) increase the rate of energy gain, or (2) decrease the rate of energy loss. (There can also be conversion between energy types, of course, but for simplicity here I am just talking about thermal energy, that is, sensible heat.)
For example, if you are lying in bed and are too cold, you can turn up the electric blanket (increase energy gain), or add a regular blanket (decrease the rate of energy loss). If you add even more blankets, you will gradually make the temperature under the blankets higher…but at the same time you make the temperature of the outer blankets colder.
Heat will always flow from higher temperature to lower temperature, but this does not mean that temperatures cannot change. The actual temperatures at different depths in the blankets depend upon the rate of energy gain and energy loss at those different depths, not just the rate of energy input into the system.
The same is true of the climate system, and when explaining the surface temperature of the Earth. It does not matter whether we are talking about radiative heat transfer, or conduction, temperature is a matter of energy gain versus energy loss.
The Greenhouse Effect Decreases the Rate of Energy Loss by the Earth’s Surface
The atmospheric gases most responsible for IR absorption and emission in the atmosphere (“greenhouse gases”) act like a radiative blanket, cooling the middle and upper layers, but warming the lowest layers and the surface.
This leads to two common misconceptions on the part of those who believe the greenhouse effect does not exist:
FIRST, contrary to the assertions of some, the rate of IR absorption and emission of atmospheric layers are, in general, NOT the same. While the rate of IR absorption does not change much with the temperature of the absorber, the rate of IR emission increases rapidly with temperature.
For example, if you took a sample of carbon dioxide gas at a very cold temperature and then irradiated it with infrared light, it would warm. (Some seem to believe its temperature would not change). The warming results because the gas would (initially) be absorbing more IR than it emits. But as it warmed, it would emit IR at a progressively greater rate. If this was the only process of energy gain/loss (IR absorption and emission), then the gas would warm until it reached a temperature where the rate of IR emission equaled the rate of IR absorption. It would end up having a higher temperature than it had before it was heated with IR radiation.
The SECOND misconception is that because greenhouse gases allow the atmosphere to cool to outer space, adding more GHGs can’t cause warming. While it is true that GHGs do lead to an overall decrease in the mass-weighted average temperature of the atmosphere, their altering of the energy budget of individual layers leads to net warming of the lowest layers of the atmosphere.
One of the first theoretical demonstrations of this was by Manabe and Strickler (1964), Fig. 4 from which I have reproduced below.
In the case of pure radiative equilibrium (no atmospheric convection, and each layer comes into radiative equilibrium), the surface and lowest atmospheric layers become very hot, while the middle and upper layers become very cold (recall my example of adding blankets over your body?)
In the real world, the atmosphere cannot support such an extreme temperature contrast, which is convectively unstable, and so heat is transported from lower layers to higher layers through convective transport (also seen in the above figure with 2 different assumed temperature lapse rates).
Since most of what we observe as “weather” is the result of convective overturning of the atmosphere, it is actually the greenhouse effect which creates weather. If the atmosphere did not absorb and emit IR energy, it would probably come to the same temperature as the Earth’s surface (an isothermal atmosphere). This would cause all atmospheric convection to cease. (I have yet to test this with a model…the vertical heat transfer from the surface would be through conduction alone, which is very inefficient in air since it is such a good insulator, and which would take a very long time to equilibrate).
By the way, if you are wondering why the stratosphere (above about 200 mb in the illustration) is so different, it is because there is a an additional radiative energy source there: solar ultraviolet energy absorption by ozone.
The Issue of “Back Radiation”
In the usual explanation of the greenhouse effect, one component of the vertical energy flows is downwelling IR radiation from the atmosphere to the surface. The existence of this “back radiation” is disputed by some people because of two seemingly counter-intuitive features:
(1) the back radiation has an average value that is even larger than the energy source for the climate system, solar radiation, which would seem to violate the 1st Law of Thermodynamics; and
(2) it flows from lower to higher temperatures, seemingly in contradiction to the 2nd Law of Thermodynamics.
But the same objections could be made against many systems which create very high temperatures. You can pump energy into a system at a certain rate, and insulate the system so that it cannot lose heat easily and thus increase temperatures to very high levels. This is because, as was discussed at the beginning of this article, the temperature of an object is related to energy gain (input) and energy loss (output)– not to energy gain alone.
So, if you continuously pump a certain number of Watts per sq. meter into a highly insulated system, the interior temperature can rise so high that the resulting infrared emission at the high temperature in Watts per sq. meter exceeds the rate of energy input into the system.
But no physical laws are violated because there are energy flows both outward AND inward at those high temperatures, and it is only the net outward flow which cannot exceed the input into the system.
A Back Radiation Thought Experiment
If you still have an aversion to the idea of back radiation, flowing against the net flow of radiation in the opposite direction, then explain to me what happens in the following example.
Imagine two plates at two different temperatures facing one another. Let’s say one plate is at 100 deg. C and the other is at 0 deg. C. It doesn’t really matter whether this is in a vacuum, or with air around the plates, the concept still applies.
It’s pretty clear that the hotter plate will lose IR energy to the colder plate at a certain rate (which will decrease over time as the plates gradually equilibrate to the same temperature).
But now imagine that the cooler plate is nearly the same temperature (99 deg. C) as the hotter plate (100 deg. C). It will be obvious to most people that the net flow of IR energy from the 100 deg. C plate to the slightly cooler plate will be at a slower rate than it was before.
But why should that be? In both cases the 100 deg. C plate is emitting IR at the same rate, yet the NET flow of IR is reduced if the cooler plate is not as cold.
The reason is that there is also “back radiation” from the colder plate to the warmer plate, which changes the energy budget (energy gain versus energy loss) of the hotter plate. If you STILL don’t like the idea of back radiation (“back” is admittedly superfluous), then just think in terms of the reduced rate of flow from the warmer plate to the cooler plate when their temperature difference is reduced.
Either way, when you reduce the rate of net energy loss from an object, the object will have a higher temperature than if you didn’t reduce the rate of energy loss.
Concluding Remarks
The effect of infrared radiation on the average temperature profile of the atmosphere is complex, and is difficult to comprehend based upon intuition alone. It was not until we developed our own radiative transfer model that we were able to build intuition regarding what happens in a greenhouse atmosphere (with or without convection).
The temperature of the Earth’s surface is an energy budget issue. Even for the same rate of energy input from the sun, the average surface temperature can vary widely depending upon the atmosphere’s ability to restrict the rate of energy loss from the surface, either radiatively or convectively.
“Compressional heating” cannot explain the relative warmth of the Earth’s surface because, if the atmosphere could not cool from IR radiation, it would warm to the same temperature as the surface. This is an isothermal atmosphere, which is convectively stable, and so all convection would stop. Without convection, there is no “adiabatic lapse rate” which describes how a parcel of air warms as it descends from a high altitude to a lower altitude.
Now, it is true that if you took an imaginary mass of air at some uniform temperature floating in outer space and dumped it onto the Earth, compressional heating would initially make the lowest layers warmer. But the final vertical temperature profile that would eventually result would be very different than the initial, as it would depend upon the resulting energy budget in each layer, which in turn would depend upon the abundance of greenhouse gases.
So, what does all of this mean for global warming? Well, exactly how much warming will occur from adding carbon dioxide to the atmosphere remains an open question. The IPCC thinks the sky is the limit. I think there is evidence that it could be quite small.
But while I am in general supportive of questioning even our most cherished and long-held scientific beliefs, I do not yet see a reason for abandoning the basic physics of the greenhouse effect.
In any comments submitted below, please refrain from strawman arguments, or diversionary tactics which divert attention from the central issues addressed above. I will not delete any comments, but I reserve the right to flag any I deem to be intellectually dishonest.
The following seems right if clouds were missing.
“Since most of what we observe as “weather” is the result of convective overturning of the atmosphere, it is actually the greenhouse effect which creates weather. If the atmosphere did not absorb and emit IR energy, it would probably come to the same temperature as the Earth’s surface (an isothermal atmosphere). This would cause all atmospheric convection to cease. (I have yet to test this with a model…the vertical heat transfer from the surface would be through conduction alone, which is very inefficient in air since it is such a good insulator, and which would take a very long time to equilibrate).”
I believe that clouds even without any “greenhouse” effect in the watervapour would make the atmosphere unstable. There would be places in clear sky where the ground would warm in daytime and places with clouds where it would be colder. Alone the day/night change and equator-pole difference would give movements of the air resulting in cloudformation. And then the stable atmosphere is gone.
So please if you can do these simulations without greenhouse effect, then be aware of the clouds anyway.
The clouds are still a big joker in the climate and weather models.
It *is* an interesting question of what the day-night cycle of solar heating does to this scenario. I suspect there would be a thin layer of convection which would form next to the surface during the day, since the daytime surface temperature would exceed the average (day+night) temperature of the atmosphere, leading to a thin layer of instability, and possibly cloud formation.
The bigger question, though, would be whether most of the oceans would freeze over without the surface warming produced by the GHE, which would increase the albedo of the Earth, and cause an ice-covered planet. It seems like someone would have done a climate model simulation of this by now…maybe they have, I don’t know.
In the example above where a blanket is added, the person stays warmer because they are generating body heat that is not dissapated as quickly because of the extra blanket. It is not only a radiation budget issue. A chemical reaction is occurring that is adding heat to the system from within. Without that heat generation, the body inside would soon assume room temperature.
There is a similar heat source inside the earth. Although it is dismissed as not part of the climate process, I don’t see how that can be so. Just below the surface of the earth, there is a hot crust, mantle and core. All that heat must play some role.
Your first point does not conflict with the point I was making.
Regarding geothermal heat flux, it averages less than 0.1 Watt per sq meter, which is tiny compare to the other energy flows in the climate system:
http://geophysics.ou.edu/geomechanics/notes/heatflow/global_heat_flow.htm
Hi Roy,
You say:
“In the usual explanation of the greenhouse effect, one component of the vertical energy flows is downwelling IR radiation from the atmosphere to the surface. The existence of this “back radiation” is disputed by some people because of two seemingly counter-intuitive features:
(1) the back radiation has an average value that is even larger than the energy source for the climate system, solar radiation, which would seem to violate the 1st Law of Thermodynamics; and”
I think part of the issue is a semantic one. The term ‘back radiation’ implies radiation emitted from the surface that is coming back from the atmosphere. In reality, only a portion of the total downwelling LW at the surface is ‘back radiation’ as defined as that which last originated from the surface LW flux. Some of it is ‘forward radiation’ from the Sun absorbed in the atmosphere yet to reach the surface, and some of it is sourced from the non-radiative flux moved from the surface into the atmosphere (water vapor which forms clouds in particular), which also radiates in the LW infrared – some of which back in the direction of the surface.
Of course, the system is far too complex and chaotic to do an accurate accounting of the three sources, but understanding the distinction is key and can help a lot I think.
yes, that’s why I said that the modifier “back” is superfluous. It is inaccurate and misleading. In any case, this is irrelevant to the points I was making.
Yes, but I still think it’s a major source of confusion and does indirectly relate to many of the other apparently largely misunderstood aspects of the GHE.
Another source of confusion and/or misunderstanding seems to be the concept of net energy flux entering the surface from the atmosphere, as this is really what ultimately determines the surface temperature and subsequently the surface LW flux as well (about 390 W/m^2). Of course, the net energy flux entering the surface from the atmosphere is a chaotic combination both radiative and non-radiative flux. So is the net energy flux from the surface into atmosphere. The key thing to note is the energy in the atmosphere is not monotonically increasing, which means that all the energy, radiative and non-radiative, that is in the atmosphere is either on a path where it will be radiated out to space or returned to the surface in some form (radiative or non-radiative).
I know you diagree with this, but I don’t think the accepted energy flow diagrams (i.e. Treberth, etc.) of the GHE accurately depict these fundamentals, and that this is major source of confusion and/or misunderstaning.
Hi Roy:
You seem to believe that the emission of heat energy from a hot body (plate) is independent of the temperature of the surrounding medium (the other plate). What is your scientific evidence that this is the case? In particular you seem to indicate that even in an environment of the same temperature, a body would continue to emit heat energy. Again
At the same time you seem to indicate that one can as well forget about backradiation with its confusing “back” and simply talk about net flow of heat energy from hot to cold depending on the temperatures involved. Why can’t you then do this, and simply stop to speak about backradiation? Or do you have some hidden motivation to speak about it?
Best regards.
Claes
Yes, Claes you found me out. I have nefarious motives for using certain terminology. It’s simply to annoy you. 😉
OK, since you want a serious answer, Claes…
The evidence you seek is beautifully produced by a handheld infrared thermometer. If the IR thermometer is at room temperature, and you point it at the inside of a refrigerator, it reads a cold temperature. Why? Because the refrigerator-viewing side of a thermopile inside the IR thermometer cools in response to the extra loss of IR energy toward the cold target. Circuitry inside the IR thermometer estimates the temperature of the viewed target based upon the rate of temperature drop of one side of the thermopile.
If you point the thermometer at a hot target, the opposite happens.
Regarding ‘back’ radiation, “a rose by any other name is still a rose”. The downwelling IR radiation emitted by the sky toward the ground still exists no matter what you call it.
Roy, the experience with your IR-thermometer you describe so well, concerns in both cases flow of heat energy from hot to cold, never the other way.
You write in your post:
“If you STILL don’t like the idea of back radiation (“back” is admittedly superfluous), then just think in terms of the reduced rate of flow from the warmer plate to the cooler plate when their temperature difference is reduced”.
Here you state that the “back” is superfluous, yet you don’t want to give up your cherished idea of “back” radiation. Don’t you see that this is contradictory?
You act just like Judy, first defending backradiation as a physical phenomenon, then taking a step back and saying that after all there is no “back”, that it is just a way of speaking without physics since after all only the net counts. Like Judy you have thereby backed off from backradiation and I guess you will see no meaning in continuing to send out disinformation about the non-physical phenomenon of backradiation or “downwelling radiation” which is the same. Right?
Claes,
As I understand Dr. Spencer’s thought experiment, he is merely saying the term “back radiation” is superfluous, simply because radiation in and of itself has no concept of “back”. It is an emission, regardless of direction. I do not see Dr. Spencer’s remarks as backing away from his concept, only stating that the term is redundant.
The net flow Dr. Spencer refers to is radiation emitted vs. radiation received. If I placed a completely transparent surface between Dr. Spencer’s plates, the net flow seen at the transparent plate would be radiation from the warmer plate less radiation from the cooler plate. In simple arithmetic terms, that is net.
To take the thought experiment a step further, imagine two completely opaque plates at 0K placed between the original two plates. These new plates would absorb all of the radiation from the original plates. However, the original cooler plate would not see the radiation from the original warmer plate nor vice versa. But the original cooler plate is radiating too and being absorbed by the new 0K plate.
Now, remove the 0K plates. Does that removal stop the cooler plate from radiating? No, it continues to radiate. Does that radiation have no effect on the warmer plate? Yes, it will warm the warmer plate. But the net flow is still more radiation towards the cooler plate, and less towards the warmer one. So the warmer plate loses energy, while the cooler one gains energy – even though *both* plates radiate.
With thermal radiation, it flows both ways. It flows both from hot to cold and from cold to hot. The laws of thermodynamics only require that more flows from hot to cold than from cold to hot. Only as a *net result* is energy required to flow downhill in potential.
I wonder about the relative effect og watervapours radiation/reflection/absorbtion and the clouds effect on the same.
Meteorologists often explain how it can be very cold i nighttime when the sky is clear, and nearly in the same moment tell that CO2 and H2O is a very strong greenhouse gas that traps the heat.
Normal personal observation is anyway that a clear night sky gives very low temperatures, and at the first cloud the temperature rises substantial. In the daytime it is opposite.
The concept of backradiation is experienced if you stand close to a cold wall versus a warmer wall. In the first case you literally feel the cold, because of the missing backradiation.
How do you know that it is missing backradiation that makes you feel cold? How can you distinguish this from increased emission from your body? Do you have sensors on your body sensing outgoing and incoming heat energy?
Roy…here is an article by experts in thermodynamics which has only been rebutted by people with foggy notions of the 1st and 2nd laws:
http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1161v4.pdf
Rahmstorf used your argument of a balance of energies, which these scientists dismissed as an obscure notion. Rahmstorf used a positive balance of energies to explain why the 2nd law was not contravened by the AGW theory. The authors explained that the 2nd law describes HEAT, not energy, which is the domain of the 1st law.
It’s difficult to absorb the difference between heat and radiative energy, but there is a difference. You said in one of your papers that most radiation from the surface misses GHGs in the atmosphere. That means the surface radiation escapes to space without even causing heat. The radiation needs to interact with a body, or molecules, to produce heat.
The 2nd law was developed to avoid situations like perpetual motion, which the 1st law allowed. The positive feedback talked about by AGW advocates is a form of perpetual motion, which is not possible in our atmosphere. Even you said positive feedback in climate science had been redefined to mean a not-so-negative negative feedback.
Specifically, Clausius talked about a warmer body warming a cooler body, and made it clear that back radiation from the cooler body could not raise the temperature of the warming body beyond it’s initial temperature. No one is arguing that back radiation cannot warm a body, the argument is that it cannot raise the temperature of the warmer body IF IT IS DEPENDENT ON THE WARMER BODY.
That’s plain common sense, Roy. You can’t get something for nothing when there are losses.
As Claes has correctly pointed out, you are describing two independent plates radiating against each other, not the situation in the atmosphere, where one surface is dependent on heating by the other. You have not accounted for losses, nor have you accounted for the fact that CO2 only radiates and absorbs in a very narrow bandwidth.
You have also totally ignored the density of CO2 in the atmosphere. All GHGs account for roughly 1% of atmospheric gases. How, in anyone’s terms can that be described as a blanket? If you had a greenhouse with 100 panes of glass, you would have to remove 99 panes to get the equivalent blanket.
CO2 accounts for 0.04% of atmospheric gases, and anthropogenic CO2, according to the IPCC is a fraction of that amount (about 4% of the 0.04%). Please explain how such a rare gas acts as a blanket, unless it is completely threadbare.
It’s refreshing to see an explanation of this that doesn’t involve spitting at those who might disagree.
Your explanations make perfect sense to me.
Thank you.
This is not an answer in a scientific discussion. Please be serions and give a serious answer, if your post was meant to be serious.
Claes
Claes:
I was responding to your accusation that I have some sort of “hidden motivation”. I’ll be scientific when you do the same.
Forget about hidden motivation Roy, and answer my question about the scientific evidence of flow of heat energy from cold to hot which is the backradiation you are returning to. And don’t say that the evidence is a handheld IR thermometer, because this is no real scientific evidence of flow of heat energy, only temperature. I expect a serious answer and not more tricks.
But Claes, a change in temperature of one side of a thermopile inside an IR thermometer *IS* evidence of heat flow. No tricks.
If you don’t understand something this elementary, we have no common ground for discussion.
Well Roy, as you well know I have written extensively about the non-physical aspect of backradiation and its lack of support in physics theory. I ask you a serious question about your evidence and you respond with either a laugh or triviality. Why not take my question as a serious question, or simply stop using the concept of backradiation. Judy gave it up after a discussion with me. You seem to be close to the same conclusion, since you write yourself that one can as well forget about backradiation and only speak about net flow. Right?
Best regards, Claes
Claes,
I really don’t get your objection. Are you claiming that downward emitted photons in the atmosphere cannot travel from the colder atmosphere toward the warmer surface?
If this were true, how do the photons from the Sun travel through the colder upper atmosphere and reach the surface?
Radiative heat transfer is a wave phenomenon of electromagnetics, not a particle phenomenon of photon particles flying like bullets from the Sun to the Earth.
I keep seeing ‘heat energy’ when there is no such thing. Maybe this is pedantic but heat is a process not an object. Heat is the flow of energy from one location to the next. In this context IS it fair to say thermal energy or molecular kinetic energy? Usually, I think people know what they are talking about and it makes little difference to the discussion as its easier to say ‘heat’ when we all know what we are talking about. However, with Claes questions I think it may be an issue. Hopefully I won’t be insulted immediately as at WUWT. You cannot post there without being made to feel like you don’t belong. I find this discussion board [at least this time] far more polite and worthwhile. Thanks to all.
yes, you are correct that strictly speaking in thermodynamics “heat” is a process, a transfer of energy, not energy content. But in atmospheric science (as in other disciplines) we also use the term for thermal energy content (e.g. “heat content” of the ocean or atmosphere).
While this leads to some confusion, I don’t believe it resolves the core disagreements being discussed here.
Hi Roy,
Seems to me uniform temperature is not needed for a completely non-convective atmosphere, only a temperature drop with elevation that is equal to or slightly smaller than the appropriate lapse rate (either wet or dry). Maybe a better way to put it is that the potential temperature, rather than sensible temperature, has to be either constant or increase with height to completely inhibit convection.
It is good you take the time to lay this all out. But in all honestly, I have never seen anyone who makes claims of the impossibility of back-radiation be convinced by reasoned explanations. My guess is they just do know enough physics to grasp the issue, and are disinclined to learn.
Steve, if there is a temperature decrease with height, why would there not be heat flow by conduction (or turbulent mixing) upward? What would keep the upper layers perpetually colder than the lower layers?
I believe that heat flow *would* occur, and the upper atmosphere would have no way of cooling without the ability to emit IR radiation. As a result, the upper atmosphere would warm until there was no longer a vertical temperature gradient from the surface upward.
Roy…this is not a shot at you. I spend a lot of time defending you and John on blogs and I have a high regard for both of you.
In his book on atmospheric radiation, physicist/meteorologist, Craig Bohren, describes the heat trapping/blanket effect as a metaphor at best, and at worst, plain silly.
In the link I provided to Gerlich and Tscheuschner, they go into the problem a bit, describing it as a many body problem in which radiation cannot be considered with normal vectors. One of them, Gerlich, is an expert in the vectors and tensors of fluid flow. Bohren put that in words by claiming photons of surface energy cannot be considered as truant school children being collected by a truant officer.
Photons are imaginary devices defined as having momentum and no mass. They were intended to particalize light energy but Einstein admitted in the ’50s that it was still not known if light is a wave or a particle. Planck did not distinguish between light and heat.
We really have no idea how surface energy operates as it travels through the atmosphere. Your colleague, Richard Lindzen, has a different explanation than you do, and claims the GHE theory is too simplified.
I think we tend to get a little too glib with our understanding of complex processes, and certain climate scientists have taken far too much license with their inferences about physics. You mentioned Trenberth, who I regard more as a politician and alarmist than a scientist. In the Climategate emails, he essentially admitted that the warming has stopped.
In your back-radiation theory, you first have to study how a CO2 molecule, which has absorbed IR and raised it’s temperature can exist in a non-thermal equilibrium for more than an instant.
How is it that we have focused on gases that make up 1% of the atmosphere and ignored gases that make up the other 99%? I subscribe to the theory that our oceans have a lot more to do with atmospheric warming than GHGs.
Gordon, your comment is a laundry list of issues. Some I agree with, some I don’t. In any event, I don’t see anything that specifically refutes a specific point I made.
Lindzen’s explanation of why adding GHGs leads to warming is consistent with mine…I just think what I described is a more thorough explanation.
I believe that the current understanding of how molecules which enter an excited state can almost instantaneously transfer extra energy to neighboring molecules is already understood pretty well:
http://www.drroyspencer.com/2010/06/faq-271-if-greenhouse-gases-are-such-a-small-part-of-the-atmosphere-how-do-they-change-its-temperature/
I agree that often our metaphors are inaccurate and that ‘true’ experts in the field often hate them for oversimplification. NOT being an expert I do not know what we would replace our current metaphor with. It is meant to make the complex easier for the uneducated [in the field] understand. I will ask what evidence there is to say that warming has stopped. 8 of the last 10 years are warmest on record. 1998 being tied with 2005(?) now. 2011 is the warmest La Nina ever. Using these short time frames is always misleading. Lets get the next ten years measured 🙂
I’m an accountant, not a scientist. But curiousity over the past two decades about the global warming issue has led me to follow various blogs (both pro and con) where explanations in deep scientific terms do me little good.
I’ve found Dr. Spencer’s blog refreshing since he generally, as here, writes in layman’s terms … quite helpful and much appreciated.
Gordon Robertson raises a point I’vde struggled to understand. Perhaps you can help clarify things. He said …
“CO2 accounts for 0.04% of atmospheric gases, and anthropogenic CO2, according to the IPCC is a fraction of that amount (about 4% of the 0.04%). Please explain how such a rare gas acts as a blanket, unless it is completely threadbare.”
As a beancounter, I look at 0.04%, noting that’s the same as 40 cents out of $1,000. If the AGW views are to be believed, how in the world can such a tiny fraction of the atmosphere have such a huge claimed impact upon global temperatures?
Many thanks, and keep up the constructive work and dialogue.
Yes, CO2 is a tiny fraction. But all of that is taken into account. CO2 is MUCH more efficient IR absorber/emitter than (say) nitrogen or oxygen…much more than is needed to make up for its tiny concentration.
In my opinion, the *best* quantitative evidence of the greenhouse effect is infrared measurements of upwelling radiation at thousands of IR wavelengths from spaceborne radiometers. The most recent instrument is AIRS on NASA’s Aqua satellite. These measurements validate that certain wavelength regions are partly opaque, with effective emitting levels very high in the atmosphere. Of course, water vapor is the main greenhouse gas.
Steve Fitzpatrick…….”I have never seen anyone who makes claims of the impossibility of back-radiation be convinced by reasoned explanations”.
Can’t get the Reply button to work.
Try this: http://realplanet.eu/backrad.htm
My arguement is earth’s climate has been and will continue to be driven by three harmonic drivers. Past history shows this to be the case.
1. MILANKOVITCH CYCLES. 100,000 YEAR TIME FRAME.
2. SOLAR GRAND MINIMUM AND SOLAR MODULATION CYCLES. 172 YEAR TIME FRAME.
3. PDO/ENSO HARMONIC CYCLES, TIED TO THE SUN . 60 YEAR TIME FRAME.
The combination of those three items determine how the temperatures of the earth will respond. Not CO2, which is a trace gas, and which has had a trace increase. There is no way that could be the main driver of earth’s climate.
As I have said, it looks like we are in a solar grand mimimum ,and I fully expect a decline in overall global temperatures in response to this. I dare say if solar flux readings from the sun average 90, or even 100 or lower, for this decade, the temperature response will be down.
THE PHASE OF THE ABOVE ITEMS
MILANKOVITCH CYCLES – are on balance in a slighty cool pahse, due to precession ,bringing the earth closest to the sun during the N.H. winter(cold phase), while earth’s tilt, and orbit are probably in a neutral to slightly warm phase.
SOLAR CYCLE- is in a very cold phase due to the prolong solar minimuM we are in, and should remain in for the next 30 years on balance.
PDO/ENSO – have now been in their cold phase since year 2009 ,and on balance should stay that way for the next 55 to 60 years.
So to sum this up, as far as these items influencing earth’s temperatures ,we have Milankovitch cycles in a slighty cool phase, we have the solar cycle probably entering a deep cold phase ,while the PDO/ENSO are in a cold phase.
The result of the above, is going to be colder temperatures as this decade proceeds. The additive wild card to the colder outlook, being how much VOLCANIC ACTIVITY ,might occur. Again past history suggest during prolong solar minimum events, volcanic activity tends to increase.
There is no way a trace gas such as CO2 ,can compete with the items I have mentioned in the above, when it comes to what will drive the climate of the earth.
I fully expect before this decade comes to an end my thoughts and others who agree , will be proven to be correct.
I agree that changing CO2 is probably not the “main” driver, either. It *could* be, but just because its the one we understand the most and can measure the most accurately doesn’t mean its the most important. To believe so is like the person who lost something in the dark, but only looks under street lights when attempting to find it.
Roy:
Since you don’t answer my serious question in a serious way I repeat it in a blog post:
http://claesjohnson.blogspot.com/2012/02/why-is-roy-spencer-not-serious.html
and ask you to answer in a comment to the post.
Seriously,
Claes
“In your back-radiation theory, you first have to study how a CO2 molecule, which has absorbed IR and raised it’s temperature can exist in a non-thermal equilibrium for more than an instant.”
Thermal motion and molecular impacts produce a small population of CO2 molecules which are in an excited state at all times. Any of this population can emit 14 micron IR spontaneously. When a CO2 molecule absorbs at 14 microns, it is promoted to a excited sate, and as you say, it almost always immediately drops to an unexcited state (is “quenched”) by a molecular collision, without ever emitting at 14 microns. So absorption warms all the molecules in the gas (even the ones that don’t absorb). But when the temperature is higher, the population of of CO2 molecules which are (randomly) in an excited state increases. The larger population of excited molecules means greater emission at 14 microns.
So even though the specific CO2 molecule that absorbs is almost always not the same one as emits, absorption and warming automatically leads to increased emission.
Gordon Robertson,
The site you link to is full of nonsensical mumbo-jumbo. As I said before, I have never seen even one person who believes back radiation is impossible be convinced otherwise. They just don’t know enough physics to understand the explanations. Maybe there exists such a person, but I have never heard of one.
All this time being spent on a trace gas ,with a trace increase, as a driver to earth’s climate, shows the sad state,climate science has entered.
All the attention, instead of being devoted to what I have outlined in my previous remarks, is instead being WASTED on this trace gas.
This is laughable, but sad. What a waste of time.
To some extent, I agree with you Salvatore. So, I’m trying to get people to quit wasting time trying to disprove the existence of the greenhouse effect. There are more important uncertainties in global warming theory which need to be addressed.
Steve Fitzpatrick…it’s one thing to call an article mumbo jumbo and quite another to explain why. Heinz Thieme has a Masters degree in engineering, and anyone who has studied engineering knows how much work goes into that.
As Thieme points out in the article, even NASA has dropped back-radiation from it’s atmospheric diagrams.
Thieme was cited in the paper by Gerlich and Tscheuschner, one of whom specializes in thermodynamics and the other of whom teaches in the field.
How does one go about proving back-radiation when 52% of solar energy is in the infrared band. What is warming the GHGs, solar energy or surface radiation, and in what proportion? How does one distinguish radiation that has been gathered from the surface and radiated back from energy that has been gathered from the Sun and re-transmitted?
Arguments are made that radiation can be measured when the Sun sets, but is that energy retained from solar heating or from surface heating? When the Sun sets, the surface should cool as well.
Thieme tries to use vectors to illustrate the futility of equal and opposite flows of radiative energy, but as Bohren and G&T have pointed out, it’s not nearly as simply as that. Radiation does not obey simple vector addition in the atmosphere.
The point is, what is being measured, and how does it fit within the scope of the 2nd law? It is simply not possible for back-radiation to raise surface temperature as implied in positive feedback leading to a tipping point.
Gordon, the climate models take into account the near-IR and IR solar input into the climate system. This is why the Kiehl and Trenberth energy budget diagram shows so much sunlight directly absorbed by the atmosphere, before it reaches the surface.
Much of this is absorption outside the visible spectrum is due to water vapor absorption, but relatively little from CO2. This can be seen from the solar spectrum overlaid with the main absorption bands, for example:
http://en.wikipedia.org/wiki/File:Solar_Spectrum.png
Response to the posts of Claes Johnson of February 19, 2012 at 10:30 AM and at 1:22 PM.
Claes Johnson asks: “You seem to believe that the emission of heat energy from a hot body (plate) is independent of the temperature of the surrounding medium (the other plate). What is your scientific evidence that this is the case?”
Christopher responds: Claes’ question was answered by Pierre Prevost in 1791 (Journal de Physique (Paris) 38: 314-322). Prevost’s answer analysed experiments that allowed two bodies to exchange radiant heat. Further experiments, especially by John Leslie, but also by many others, over many many years, verified Prevost’s analysis. A translation by D.B. Brace of Prevost’s paper is provided in ‘Harper’s Scientific Memoirs’ edited by J.S. Ames, American Book Company, New York, 1901. The matter is explained by Balfour Stewart at http://www.archive.org/stream/elementarytreati00stewrich#page/182/mode/2up. A detailed account by Max Planck is to be found at http://www.archive.org/stream/theoryofheatradi00planrich#page/n5/mode/2up. A brief account, with plenty of basic literature references, of it is to be found in J.R. Partington, ‘An Advanced Treatise on Physical Chemistry’, volume 1, ‘Fundamental Principles. The Properties of Gases’, Longmans, Green and Co, London, pages 467-468 in Section 4, ‘Radiant Heat’. An unbiased detailed account of it, specialized for the atmosphere, is to be found in Paltridge G.W. and Platt, C.M.R. (1976) ‘Radiative Processes in Meteorology and Climatology’, Elsevier, Amsterdam, ISBN 0-444-41444-4. A less detailed account for the atmosphere (admittedly with a bias intending to persuade you to believe in the AGW rubbish) is to be found in Wallace, J.M. and Hobbs, P.V. (2006) ‘Atmospheric Science. An Introductory Survey’, second edition, Elsevier, Amsterdam, ISBN 978-0-12-732951-2. It is regrettable that most thermodynamics textbooks have little to say about this. Prevost’s original work is so deeply ingrained into the average physicist’s general understanding that he does not bother to attribute it explicitly to Prevost, he just assumes it as ‘obvious’.
A short statement of the situation is as follows.
Let us consider a body situated so that its temperature is uniform throughout its extent, and unchanging in time. For this ideal situation, there must be a suitable supply of heat to balance any loss. The usual ideal model for this is a body placed in a cavity with opaque walls that absorb and emit radiation of all wavelengths, kept, until thermal equilibrium is reached, at a constant temperature by some thermostatic device; the rest of this ideal cavity is to be evacuated.
Then thermal radiation will leave the surface of the body, partly by reflection of radiation incident on the body, and partly by spontaneous radiation directly originating in the material of the body.
The spontaneous radiation emitted by the body and directly originating in the material of the body is logically determined entirely by the nature of the material of the body and its interface with the remaining space in the cavity, the wavelength of the emitted radiation, and the temperature of the body. This statement may be justly attributed to Prevost.
If the body is suddenly removed from the cavity and exposed to the cold and dark of outer space, it will continue to radiate. In the first instant, before there has been time for the body to cool significantly, the radiation emitted by the material of the body will be just the same as it was in the cavity. Then the radiation emitted by the material of the body is logically determined entirely by the very same factors as stated just above.
There will be practically no radiation incident on the body, now that it is directly exposed to the cold and dark of outer space; consequently there is practically no reflected radiation from body. Over time, the body will then cool, its temperature becoming less, and the radiation that it emits will consequently also become less, but here our interest should focus on the processes of the first instant after removal from the cavity, when we briefly know the uniform temperature of the body.
Causally, as distinct from merely logically, the temperature of the body is continuously governed by its adventures in its environment. The temperature of the body is well defined and uniform when the body has had time to reach thermal equilibrium with its constant temperature environment. But once reached, that temperature tells logically all that is needed to determine the radiation that the material of the body emits, given also the nature of the material of the body and its interface with its contiguous medium.
Dear Claes Johnson, now it is your turn. Above are some leads for you to read; they tell of abundantly repeated experimenal evidence for Dr Spencer’s statements. If you have time and facilities, you yourself can repeat some of the experiments.
Dr Spencer cannot actually do your reading for you. You have to do it yourself.
I have read and written extensively about blackbody radiation and the non-physical aspect of backradiation. Read and comment if you want to discuss the issue.
Thanks Dr. Spencer; A very good article.
You now have four new links from my climate and meteorology pages.
To Claes
Could you set up an experiment or way of measuring that could prove that the thermal radiation from a body depends on the surroundings?
I believe a mirror in 45degr angel between the two plates and some bolometer could show that the radiation from the plates are independent of the other plate.
See my response to Claes, above…a handheld IR thermometer provides the proof he is seeking.
Snakes take on the temperature of the surrounding and thus may be indifferent to that temp, but for human beings it does not take much experience to know that the heat transfer from your body is affected by the surrounding temp, right?
As an athlete I notice that its my body that generates heat and has to get rid of it otherwise I run into problems. when not working out and its cool then my heat can escape easily through normal blood circulation flow and the flow increases to the extremities as outside temperature rises. When that system starts to get overloaded I start to sweat and the latent heat transfer starts to kick in. In all this my body is still trying to transfer the same amount of heat for the level of exercise. In my thinking this is independent of the outside temperature. It’s just my body operates differently to transfer it.
I not a scientist but interested in understanding what I observe which sparked this reaction.
Don’t you notice a difference in workout on the Equator and at the North Pole?
In colder climates I loose the heat more easily and the air is more dense and thus more oxygen for each breath.
In warmer climates I sweat more and breathing is harder.
In either case I still need to get rid of the heat and on balance it’s better on the colder side.
Hope this answers.
Doug said: “The reason it does not happen is because the absorptivity of the surface does in fact reduce to zero for radiation coming from a cooler source.”
The absorptivity is integrated over all frequencies and cannot reduce to zero.
Doug also said “Such radiation merely resonates or is “rejected” in some way”
Based on the frequency? If that is the case how does the higher frequency radiation from the cooler source (albeit less of it) get rejected? The radiation curve from the cooler source does peak at a lower frequency than the warmer source, but that curve still contains higher frequency emission.
Thanks a lot Christopher, It will be good to read the masters!
I would suggest thought experiments are inadequate to describe backradiation. I frequently see depictions of X watts being absorbed by a greenhouse gas and X/2 being radiated up and the X/2 radiated back to the surface.
First off that leaves nothing for warming anything within the gas.
Secondly it suggests the gas is has a blackbody temperature 1/2 that of the surface, which is a bit hard to swallow. It seems to me it operates like a heat flow train and any delay in outgoing is the process of warming the gas.
Likewise say the train is 390watts/m2, the object is 10 watts from equilibrium, the warming rate is 10 watts. As 380 watts is going out the backside towards space. But at the start if it had no heat the warming rate is 390 watts (keep in mind watts is a energy/time measurement.)
The inverse would apply to the object cooling if it cools and it does not have a continuous source of energy.
Its important to note here the SB equations are based upon looking at one side of an object. The equations would be different if were a sum of both sides.
So I don’t buy the thought experiment and slowing rate as evidence of backradiation, I need to see the blueprints of it, calculations, and a demonstration.
A real form of more or less back radiation is reflection. Reflection barriers are used extensively to slow cooling or warming.
______________________
Another issue is incoming. Dividing by 4 to get average radiation per surface area does not apply to 3 dimensional transparent masses. Incoming solar may be only 1/2 longwave but as soon as that sun peaks over the horizon molecules elevated above the surface are getting a full share of it at 683 watts while the surface has to average half of whats left. If we look at some of the NASA, I think Univ of Rhode Island budgets, they show the atmosphere absorbing 65 watts incoming and only 51 watts outgoing. Seems to me that amounts to a net warming for the atmosphere and a net cooling for the surface. I could be wrong I suppose.
_____________
I also enjoy your comment that if the atmosphere could not cool by radiation it would go isothermal.
I suggest that the temperature it would go isothermal, assuming zero radiation out going, would be the SB equivalent of 1,365 watts or 121C about the temperature of the sunny surface of the moon. There would be a nasty inversion layer very near the surface however.
It would get that way on the same principle a 100% passive solar water heater is able to elevate the temperature of water in a well insulated tank to an average quite a few degrees above the average ambient temperature.
In a non-radiative atmosphere all the conditions are in place for that and it would be warmer and isothermic as long as the loss rate from radiation was less than the conduction/convection rate feeding it and you could do better and create a steeper inversion layer at the surface because losses by conduction would be far less in air than water.
What this implies then is what the excess of incoming absorption over outgoing absorption implies namely greenhouse gases are cooling to the surface. . . .which suggests that additional CO2 has a quite minor effect having been blown away by the modern warming.
I like this theory far better because at least I can demonstrate how it works.
I reposted this to make it more readable. Sorry for not proof reading the first version:
I would suggest thought experiments are inadequate to describe backradiation. I frequently see depictions of X watts being absorbed by a greenhouse gas and X/2 being radiated up and the X/2 radiated back to the surface.
First off that leaves nothing for warming the gas.
Secondly it suggests the gas has a blackbody temperature 1/2 that of the surface. Thats a bit hard to swallow. When one looks at the chicken and egg problem (if a ball is cooling what cools first, the core or the surface) it seems how it operates is like a heat flow train. Any delay in the train is the process of warming the gas atmosphere.
Say the train is running at 390watts/m2 and the object is 10 watts from equilibrium. The warming rate is 10 watts. 380 watts is going out the backside towards space. But at the start if it had no heat the warming rate was 390 watts (keep in mind watts is a energy/time measurement.) That seems more than accurate enough to describe a slowing. For the warming object like the soil it may not apply as the restriction may be conduction within the heat mass or in the case of a continuous input source there is no cooling.
Its important to note here the SB equations are based upon looking at one side of an object. The equations would be different if were a sum of both sides.
So I don’t buy the thought experiment and slowing rate as evidence of backradiation, I need to see the blueprints of it, calculations, and a demonstration.
A real form of what you might call or mistake for back radiation is reflection. Reflection barriers are used extensively to slow cooling or warming. Everything almost certainly has some degree of reflectivity as I understand the search is ongoing for the perfect blackbody.
______________________
Another issue is incoming. Dividing by 4 to get average radiation per surface area does not apply to 3 dimensional transparent masses.
Incoming solar may be only 1/2 longwave but as soon as that sun peaks over the horizon molecules elevated above the surface are getting a full share of 1366 watts and its going to average 683 watts. Meanwhile the surface to which a meter squared applies for absorption has to average a 1/4th of whats left after absorption by the transparent atmosphere. The ocean may represent a similar effect.
If we look at a Univ of Rhode Island, as I recall, budget posted (at least at one time) on the NASA site. They show the atmosphere absorbing 65 watts incoming and only 51 watts outgoing. Seems to me the 65 watts amounts to a net cooling for the surface. I could be wrong I suppose.
_____________
I also enjoyed your comment that if the atmosphere could not cool by radiation it would be isothermal.
I suggest that the terminal temperature would be the SB equivalent of 1,365 watts or 121C, about the temperature of the sunny surface of the moon. At night there would be a nasty inversion layer very near the surface.
It would get hot using the same principle a 100% passive solar water heater uses to elevate the temperature of water in a well insulated storage tank by convection. The average temperature of these systems are quite a few degrees higher than the average ambient temperature.
In a non-radiative atmosphere all the conditions are in place for this to occur if the gases in the atmosphere did not absorb or emit IR. It would be warmer all the way to the ground and isothermic except a last little distance to the surface (a few inches or feet), relatively undisturbed by a lack of convection, as long as the loss rate from radiation was less than the conduction rate feeding it heat. The solar water system has less perfect storage insulation and a lot better conductivity so the water system has more losses. Some sellers of these devices advertise 30C average temperature elevation. No doubt on cloudless days but with a non-radiating atmosphere there would be no clouds or water vapor to shade the collectors either.
What this implies is as you add greenhouse gases it cools the atmosphere a lot and cools the surface by bringing on convection. It also suggests that additional CO2 has a very minor effect having been blown away by the modern warming.
I like this theory far better because at least I can demonstrate how it works.
Bill Hunter,
Although I’m no expert I just wanted to share my understanding of some of the issues you raised.
You mentioned the thought experiment where an atmosphere absorbs X radiation from surface and emits X/2 back to surface and X/2 up, and wonder what portion remains to heat the atmosphere. The answer to this is in exploring the definition of temperature. There are two separate things going on. The hypothetical atmosphere object is absorbing X which is the source of thermal energy. The total of X emitted from the atmosphere is due to the temperature of the atmosphere. In this case we are looking at the equilibrium temperature (and note that incoming solar X/2 would be the starting point for reaching this equilibrium). If there were more radiation being absorbed than what is emitted in the atmosphere (neglecting all non-radiative forms of heat transfer – eg if there were a vacuum layer between surface and atmosphere) then the temperature of the atmosphere would be increasing.
In a real atmosphere which does not actually look like discrete black-body layers separated by vacuum I think the description of back radiation is not intuitive. I like to think of the atmosphere as having limited conductivity for radiation. In other words, it is resistant to flow of radiation. Analogous to ohms law; consider the incoming flow of radiation from sun as a fixed current. The atmospheric resistance to current (radiation) means it must build a larger potential across it (temperature) in order to conduct this fixed current out to space. Note: and convection is a parallel voltage regulator that extends across the troposphere.
I don’t understand your point about transparent mass and divide by 4. The divide by 4 is due to the fact that surface area of earth is 4*pi*R^2 but the earth blocks pi*R^2 of light.
I think that the high/low daytime/nighttime moon temperatures are due to low heat capacity of the moon relative to the earth. Or perhaps the lack of atmosphere and longer day/night cycle. In any case you can’t make a direct comparison between 130C of illuminated moon surface with 18C of earth which is a sort of average temperature over the whole earth surface. Average temperatures is a whole other issue that requires a longer explanation that what I would offer here. See http://scienceofdoom.com/2010/06/03/lunar-madness-and-physics-basics/ which is the place where I read about this topic.
this is what I don’t understand, the upper atmosphere is not a “few degrees” colder than the surface, it is over 30C cooler just 30K feet up… I understand that slowing the release of LW via GHG increase would add to the radiative budget and raise the height of LW emission, but not even accounting for the value of incoming SW from the Sun, I think many are forgetting another seperate issue regarding the 2nd law of thermodynamics that has NOTHING to do with backradiation or violation of the physical law.
Energy is only sustainable in THERMAL form (in a transparent recieving body) at the threshold at which the recieving body is NOT at equilibrium with the warmer conducting body and it’s emission (the Sun).
Look at ALL the global winds, ocean waves, pararazzi-like lightning, cyclones, jet streams, clouds, etc…NONE of that KINETIC energy would be possible without the GHE! The GHE induces convective overturning which is basically natural transfer from thermal energy to kinetic energy…the KINETIC portion of the budget is very large, and it is all there via the GHE.
It isn’t that there can’t be backradiation or an initial warming of the atmosphere, as there can be, but is is unmeaurable as within a matter of hours, it is regulated. Dr. Spencer’s simple model and TERRA satellite data revealed the faster release of LW energy than progged by GCM’s, because the system is open/transparent and at equilibrium with the Sun, in some way the law must remain intact…energy will be released or at least not sustained in thermal form.
Adding GHGes hence may warm the surface to an unmeasurable levels over decades, but you’d expect a slight cooling in the upper TLT by the reasoning above, equilibrium time is actually a matter of hours. Decreasing or reconfiguring cloud cover is the only way to directly increase the thermal energy budget of the oceans and the atmosphere.
The issue of assumed warming by backradiation is discussed in my post here …
http://wattsupwiththat.com/2012/02/19/open-thread-weekend-8/#comment-897342
This is very simple, and probably stupid. I know this has been said, but I don’t understand why it doesn’t work. If we talk, very reasonably, about energy in / energy out, and we want to quantify the effect of some gases reducing the outbound flow, we need to know the effect of all the other elements reducing the outbound flow. Total effect minus other element’s effect equal greenhouse gases effect. And it seems to me oceans (water surface instead of land surface) are the big elephant in the room.
Of course adding greenhouse gases will add temperature. But if you have a total effect shared between a mouse and an elephant, making the mouse bigger won’t add a lot to the total effect.
I know I am wrong because so say the experts. But I don’t know why. Anyone?
Please kindly have a look to my recent post below. It answers your question – in my humble opinion.
If an elephant alternatively changes what it´s doing for just the opposite, but the mouse continuosly acts in the same sense, the later eventually wins.
I don’t think so, but thanks. The mouse will have and effect, for sure. But if the effect is adding 100, 200, 300 grams to the weight of the elephant, I wouldn’t call it a “win”.
But thanks a lot.
The temperature of the Earths surface is not uniform it gets warmer at the equator than it does at the poles when the sun is visible during the day.I don’t think that the convective cells would stop operating if the atmosphere had no greenhouse gasses.the atmosphere above the warm part of the Earth will gain kinetic energy and rise but gravity will remove this energy of motion so that the temperature would never be uniform top to bottom while the surface is being warmed, then there is sideways motion of the atmosphere to parts of the Earths surface which get less warming during the day.I am not an expert but it makes sense to me that the atmosphere will continue to connect if we had no greenhouse gasses and the mass of the atmosphere remained as it is.
The temperature of the Earths surface is not uniform it gets warmer at the equator than it does at the poles when the sun is visible during the day.I don’t think that the convective cells would stop operating if the atmosphere had no greenhouse gasses.the atmosphere above the warm part of the Earth will gain kinetic energy and rise but gravity will remove this energy of motion so that the temperature would never be uniform top to bottom while the surface is being warmed, then there is sideways motion of the atmosphere to parts of the Earths surface which get less warming during the day.I am not an expert but it makes sense to me that the atmosphere will continue to convect if we had no greenhouse gasses and the mass of the atmosphere remained as it is.
yes, you might be correct, and for the reasons you cite. The nature of the convection would be vastly different, though. Probably much larger scale, with much weaker vertical motions. For example, there are planetary scale vertical circulations in the stratosphere, but no smaller-scale circulations because of the extreme static stability.
Salvatore del Pretre says (yesterday):
“All this time being spent on a trace gas ,with a trace increase, as a driver to earth’s climate, shows the sad state,climate science has entered.
All the attention, instead of being devoted to what I have outlined in my previous remarks, is instead being WASTED on this trace gas.
This is laughable, but sad. What a waste of time”.
You yourself use several times, in a previous post, the word CYCLES.
I would completely agree with you if the “trace” gas CO2 were changing up and down in cycles. But IT IS NOT … due to what we all know.
And, slowly but surely, it is winning “the war”.
Was the much much stronger who won in Vietnam?
‘Climate science’ needs remedial physics’ education.
‘Back radiation’, in reality ‘Prevost Exchange Energy’, exists. Climate science’s mistake is to think that just because you can measure it, shielding the detector from radiation going the other way, it is from an energy source so can be converted to heat. I can’t overemphasis just how badly wrong is the Trenberth-Kiehl heat flow analysis; the double counting of energy leads to totally imaginary positive feedback.
To explain, you need two basic laws, Equipartition of Energy, Local Thermodynamic Equilibrium. These mean that in any system the thermodynamic states are in equilibrium in terms of frequency distribution, also any entity at a particular energy level can’t be distinguished from another such entity. So, once an IR or other energy quantum has been absorbed by a particular site in the density of states, its origin is forgotten.
Consider two bodies at the same temperature and in radiative equilibrium. Radiative fluxes predicted by S-B for emissivity and view factor are identical so there is no net energy flow. Delve more deeply: radiation from Body 1 absorbed by the IR or other density of states at or in Body 2 becomes indistinguishable from other occupied states and comprises exactly half the total number of those states. The same goes for Body 1. So, equal radiation from both bodies and it’s all Prevost Exchange so does no work.
Reduce temperature of Body 2. Its radiative flux to Body 1 decreases so more of that IR density of states is filled by interior kinetic energy than incoming radiation. The difference between the two fluxes is the increase of net radiation to Body 2. At Body 2, more of its density of states is filled from incoming radiation so the balance shifts to conversion of that net energy to heat. In short, ‘back radiation’ is a standing wave which controls heat transfer and can do no thermodynamic work.
‘Climate science’ has also got IR physics wrong; you can’t get direct thermalisation of IR absorbed by GHGs. The absorbed quantum can only be transferred to another GHG molecule with the right IR state. At the same time as is absorbed another, thermally excited state [for CO2 about 5% of molecules at room temperature], will emit the same quantum in a random direction, restoring LTE.
If this quantum hits the earth’s surface, cloud droplets or bare aerosols at equal or greater thermodynamic temperature, it Prevost exchange and can do no work. If absorbed by another GHG molecule, its direction is changed. If it hits an aerosol at lower temperature, the net part of that exchange above Prevost Exchange is converted to heat.
Hence thermalisation is at middle and upper clouds or bare aerosols, mostly the former. As [CO2] increases, convection increases. I am sure climatologists will be able to argue what happens next better than me but my belief is that this is the physical mechanism by which Miskolczi’s constant IR optical depth is achieved; there can be no GHG-AGW.
PS the problem climate science has is that Tyndall’s GHG experiment was done at constant volume so much of the rise in temperature was from the increase of pressure of the CO2, for which the coefficient of thermal expansion is higher than for ‘permanent’ gases like N2 and O2.
[Cp for CO2 also rises by 13.1% from 250 to 350 K as it develops the 14 and 15 micron bands/oscillations]
The modern ‘gas in bottle ‘ experiment has the same fault – loosen the cap and temperature rise is much lower. it’s also from the walls of the bottle, not direct thermalisation.
A lot of scientifically-challenged people have failed to think out very simple experiments but this is what you get from expanding the number of people in science, so you lose average intelligence!
Climate science is a failed science, and the discussion here, which ignores the definitive facts, well shows why. Fifteen months ago, I showed by comparing the temperatures in the atmospheres of Earth (with .04% carbon dioxide) and Venus (with 96.5%) that there was NO greenhouse effect at all (no increase in temperature at a given pressure level due to the HUGE difference in carbon dioxide in the two atmospheres), but that the ratio of temperatures, Venus/Earth, depended ONLY upon the ratio of the two planets’ distances from the Sun. This is the hard fact, that academics and other believers in the greenhouse effect (whom I have informed, long ago) simply refuse to face (they can only call it a “coincidence”, or a “failure to account for albedo”–a failure, I would reply, that only exists in their own minds–because it confronts them with their own staggering incompetence, which was nourished by false scientists in positions of authority for 20 years.
All that has been argued since, including here in this thread, is just massive avoidance behavior and denial of the clear truth.
No one, that I have yet read in the internet climate debates, knows how energy from the Sun fundamentally warms the atmosphere, independently of the surface. Your vain speculations, masquerading as scientific facts, disgust me, as a dispassionate scientist seeking only the truth.
“Your vain speculations, masquerading as scientific facts, disgust me, as a dispassionate scientist seeking only the truth.”
You are dispassionate, yet disgusted? Hmmm…
Roy,
Can you please explain why Harry is incorrect? His explanation of the temperature and pressure profiles of Earth and Venus seems to be *very* straightforward and is surely an amazing coincidence if there is some error.
I think you need to be a dispassionate scientist seeking therapy.
Klaas Johnson needs to study “black body radiation”. Any body with temperature above absolute zero will emit radiation, regardless of the surrounding temperature. A hotter body will radiate more, and at higher frequency. Thus the cold felt on your side turned against the cold wall still radiates the same amount of energy but receives less radiative energy from the cold wall.
For some reason my reply to the reply function is not working so:
Mike Blackadder;
Atmosphere reflection, particularly cloud reflection needs to be dealt with.
Let me give an example:
If the cloud bottoms are 273K (0C) (radiating 315 in total, 1/2 down and 1/2 up) and my surface is 300K (radiating 459W/m2 up) and cloud reflectivity is 90% (reflecting 413W/m2).
My IR measuring device should measure what wattage coming from the sky?
Is that 570 watts? Or will my device measure just 413W?
Reflectivity for most solids is well understood. It’s tied to emissivity with a ball and chain. In fact it is tied by definition. Only when dealing with transparent gases does the water start to get muddy.
Your point on the atmosphere heating with the excess radiation is good but the question still remains if it’s by X/2 or it’s by the figure X when the temperature is 0K and gradually reduced as the temperature rises.
Further, the incoming vs. outgoing conundrum the divide by 4 average radiation figure 1364w/m2/4 equals 341 w/m2. only applies to 2 dimensional surfaces.
For transparent elevated gas molecules it would be a divide by 2 number instead (682watts/m2) as the sun peaks over the horizon 50% of the time. The reduction in intensity at dawn is due to atmosphere absorption and reflection. The surface is not ideally oriented to the sun however. Passive solar folks learn in their first lesson how to deal with this issue; they slant their collectors so they are perpendicular to the sun. Elevated transparent gases in the atmosphere are already oriented in such a fashion.
Thus since sunlight is half longwave it sounds like incoming and outgoing absorption by CO2 should be a wash. Atmospheric reflectivity should also be a wash. So one needs to maybe look for another source of warming. And I am suggesting the machine that the 100% passive solar heater represents and the fact the atmosphere/surface has all the necessary constituents 1.poor atmosphere emissivity serving as insulated storage. 2. The heat capacity of the atmosphere serving as a sink for a potentially tremendous amount of heat. 3. Gravity to run convection and prevent conduction from being a wash. 4. Relative good emissivity of the surface to act as a collector. I have designed such systems for energy cost free heating systems. The hardest issue to deal with in doing this for space heating is controlling daytime heat gain when your objective is more heat at nights and maybe even less during the day. That’s a genuine greenhouse by the way.
As to the comment about the moon surface the moon surface does have enough time to max at a maximum temperature. So would a non-radiative atmosphere at least until it is very near the surface.
With essentially conduction being a wash the question becomes how much cooling can the surface obtain (halfway between its natural equilibrium and heat being pressed on it by an isothermic atmosphere?). So surface would not be as hot on average as the isothermic atmosphere and the atmosphere would have a very sharp temperature gradient near the surface at night.
Since conduction unlike radiation is calculated on a basis of distance emissivity would need to rise a lot in the atmosphere to override near surface effects, probably to the same level of emissivity as the surface itself.
Bill thanks for your reply. This is stretching my capabilities but I’ll try to answer as well as I can.
I don’t see how an IR meter could distinguish between long wave emitted from a cloud at 0K vs long wave reflected from that cloud. I assume that your point about reflectivity being tied to emissivity is that if a body does not absorb all incident radiation also will not emit radiation like a black body. Therefore in your example the cloud at 90C should not actually emit at 315W/m^2.
This leads to the next small point I would make regarding your example. If a cloud at 0K emits 315W/m^2 then it should be emitting this amount from all of its surfaces. For example, a cloud layer completely surrounding the globe will actually emit 315 up and 315 down, so a total of 630. Obviously this can not be an equilibrium condition if the cloud only receives 459 from the surface.
I don’t agree with the divide by 2 argument just because the sun peaks over the horizon 50 % of the time or because the atmosphere is elevated. Even if there was no atmosphere there is lower intensity heating from the sun at the poles than at the equator. This is apparent after considering the geometry. Ie. think of a tree casting a longer shadow when the sun is low. If the atmosphere is absorbing some proportion of sunlight, then the effect of elevated atmosphere is only to make the earth a slightly larger circle for intersecting sunlight. You are correct though that an IR meter could be oriented to absorb at a rate of 1340W/m^2 even as the sun is rising- ; if not for the effect of the atmosphere. To reorient the earth surface in a similar way you’d have to spread it out as a flat sheet facing the sun.
I don’t think that greenhouse gases absorb 1/2 of incoming solar, but even if they did it wouldnt mean that their absorption effect was a wash. With a transparent atmosphere you would get average of 340W/m^2 from the sun and at equilibrium emit 340W/m^2. If we insert a single layer atmosphere that absorbs all long wave radiation and if we assume 1/2 of incoming radiation from sun to be long wave then 170 of sun light is absorbed by surface and 170 by the atmosphere. Equilibrium is reached when the atmosphere emits at 340W/m^2(both up and down). In this case the earth sees 340W/m2 from the atmosphere and 170 shortwave from the sun, which is much warmer equilibrium temperature compared to the transparent atmosphere (ie. the atmosphere absorbs 510 from surface and 170 from sun which supplies the 680 total emitted from atmosphere).
I don’t understand why CO2 long wave absorption is a wash just because it absorbs from both the sun and t he surface.
Harry Dale Huffman says:
February 20, 2012 at 8:22 AM
“failure to account for albedo”
I agree with your statement of mishandling albedo. My view is despite the albedo reflecting 30% of solar radiation to the sky, conduction and the winds will ensure the temperature will stabilize at 278.5K (absent my convection machine effects 🙂 ) as surely as a polished silver plate reflecting 98% of the sunlight shining on it will warm to roughly the same temperature as a black plate.
But you might get more attention to your important point with honey rather than vinegar.
When you become aware of such ideas and try to communicate them its a bit like Galileo preaching Copernicus to the Pope. The story goes that Galileo had a bishop sympathetic to his view, but when that bishop became Pope and Galileo implied the Pope was a fool he ended up under house arrest for the rest of his life.
Having read your article with interest, I would like to follow up your discussion as follows:
“For example, if you took a sample of carbon dioxide gas at a very cold temperature and then irradiated it with infrared light, it would warm. (Some seem to believe its temperature would not change). The warming results because the gas would (initially) be absorbing more IR than it emits. But as it warmed, it would emit IR at a progressively greater rate. If this was the only process of energy gain/loss (IR absorption and emission), then the gas would warm until it reached a temperature where the rate of IR emission equaled the rate of IR absorption. It would end up having a higher temperature than it had before it was heated with IR radiation.”
The statement is correct. The question is: have you ever think about what temperature the sample of carbon dioxide gas would be before IR heating? The answer is 0 K.
IR radiation makes the sample warm up, and end up at a temperature of radiative equilibrium, say 10, 100, 200 or whatever K according to how strong the radiation source is. Quantitative analysis shows the radiative equilibrium temperature for co2 molecules is only -78C with a radiation source equivelent to the earth ground surface at 12C. co2 gains heat by molecular collision with neighbour o2 and n2 to reach its actual temperature in the atmosphere.
It is widely perceived as co2 will be at the same temperature as n2 and o2 before absorption, inviting one to believe absorption warms it to a temperature higher. There is a need to make distinction between:
Absorption results in warming up of an object;
and
Absorbing objects are warmer than non-absorbing objects.
The former is always correct, the latter is correct only when there is a strong radiation source.
All molecules reflect radiation/heat including non-GHG molecules.
Clearly there is a lapse rate.
The big question is what causes it. It could be A) its all comes from reflection from all atmosphere molecules whether they absorb or not, or, it could be B) it all comes from absorbing molecules back radiating, or, it could be C) both.
In my view B) is clearly not the answer.
I know about A) (reflection) and have used it to my benefit. Backradiation is something I cannot see nor distinguish from A) so to make a case for it you first have to tell me what the value of A) is and then tell me mathematically that A) is insufficient to produce a measured effect.
Just riding roughshod over the problem running a verbal sword through reflection and planting a backradiation flag in reflection’s territory sounds more like a religious crusade than anything to do with science.
Re backradiation, Dr Spencer: Heat flow is analogous to water flow and electrical current flow (the latter two have been used to model heat flow).
Now, are you saying that if you have a resistor of 1 ohm with a voltage of 10 volts (above ground) on the left hand end of it, and 3 volts on the right hand end, there’s a 10 amp current flowing from left to right, and a 3 amp current flowing from right to left, and so a net 7 amp flow from left to right?
Equally, if you have a water tank at 1000 feet above ground level connected by a pipe to a tank 900 feet above ground level, would you say that water flows from the upper tank to the lower tank at a rate proportional to its height (1000 feet), and flows from the lower tank to the upper tank at a rate proportional to its height (900 feet), so that the net flow is the difference between these two flows?
If your answer to both these questions is No, and that in the first case the current flow is proportional to the potential _difference_ across the resistor, and in the second case water flow is proportional to the height _difference_ between the tanks, and that there’s no electrical back-current and no water back-flow in either case, then why is it when it comes to radiative heat transfer that heat loss is not proportional to temperature difference, but proportional to absolute temperature (T^4) and there IS back-radiation? What’s so different about radiative heat transfer that nothing else seems to work like it (including conducted heat)?
Frank,
Your physical descriptions aside, let’s say I were to point a FLIR camera (IR camera) at the cooler of the two plates from Dr. Spencer’s thought experiment with the warmer plate absent. I would be able to see the IR radiation from the plate. If the warmer plate were then to be placed back in front of the cooler plate, would the cooler plate disappear from my IR view? (assuming of course the camera is angled to still view the cooler plate). No, it would not disappear because it would continue to radiate.
According to your physical descriptions above, the cooler plate should simply stop radiating when in the presence of the warmer plate. But that just is not so.
With it established that the cooler plate continues to radiate, what happens when that radiation which is sourced from the cooler plate strikes the warmer plate? Does the warmer plate just ignore that energy? Can it somehow decide that radiation was from a cooler source, so it can discard it?
Obviously those are silly rhetorical questions, but the fact is the cooler plate continues to radiate, that radiation will strike the warmer plate, and that absorbed energy will have an effect on the warmer plate’s temperature.
I don’t know what I’d see. I haven’t got an IR camera.
Furthermore, what’s the temperature of this IR camera supposed to be?
Well an infrared camera can be as warm or cold as you like. You can buy a digital camera with a sensor that is sensitive to infra-red radiation. Let us say you keep the camera inside your car which is at around 22C. You wind down the window briefly and take a picture of a winter scene and then wind the window up again. All of the objects outside the car are colder than the sensor in your camera. And yet that camera will still take a picture of the scene outside the car in the infra-red.
In the “no back radiation” scenario, because the film is warmer than the scene outside the car the picture would always be black. Now that should be easy enough to demonstrate one way or another!
http://tinyurl.com/7xwd7zf
Actually, you probably do have an IR camera. Standard digital cameras with CMOS sensors are IR sensitive. The camera has a filter for the IR though to keep it from interfering with your photographs. If you are adventurous, you can take the camera apart and remove the filter.
If you wish a simpler and less expensive experiment, use the example Dr. Spencer already gave. Get an IR thermometer, and point it at the inside of your refrigerator (or freezer if you wish to be more extreme). The thermometer IR sensor is at room temperature, and your refrigerator will be some decades of degrees lower.
If your theory is correct, the thermometer will not register any temperature, or read 0K. However, you will find that the IR thermometer will register an accurate temperature – because the warmer object (IR sensor) can and does see radiation from the cooler object (refrigerator).
Its true that back-current and back flow (in this context) are not sensible ways to describe the physics, but notice that in both of these cases it doesn’t matter if you used a construct like that you’d at least arrive at the correct answer mathematically.
Say that you have two 1 pound weights traveling in the same direction at different speeds. One weight is traveling 10 feet per second faster than the other. Can you tell me the difference in their kinetic energy? It is the same problem if you try to answer the rate of exchange of radiation between two bodies if you know only the difference in temperature of the two bodies.
Thank you for the article and the very clear description.
My comments here are not referring directly to it but to the general representation of greenhouse.
Going back to the example with adding more blankets. I find it odd if one would do the energy calculation and replace the blankets with electrical blankets which have an own source of energy.
Isolation, yes, it slows the flow of energy, but is not an additional energy source.
I think this is the major problem most skeptics have with greenhouse theory, where the sun is shown as 170 W/m2 and greenhouse 320 W/m2. The radiation from the sun is net heat transfer whereas the one from greenhouse is only a member of one energy transfer and would not exist without the origin, the radiation from ground (supposing the atmosphere is not directly warmed by shortwave too which is not 100% true).
I do not think that when making the calculation for a furnace, or any engineering thermal calculation somebody replaces isolation with an equivalent energy source that would give the same temperature for a certain value.
To say we add 20 bricks here, so this is +200 W another 20 the other side now we have +400W.
I imagine it can give about the same temperature if tweaked for a certain value, and even be more or less correct for small variations but would at a certain point differ more and more from the proper calculation with heat transfer.
Heat source and thermal isolation are different things. Adding more CO2 may result in increasing the “backradiation” in the resulted energy transfer through radiation but no added Co2 creates backradiation.
I just have a simple question. This is purely theoretical and cannot be performed in real life. However let us assume we have two containers full of CO2 that are totally transparent to the infrared radiation that a CO2 molecule can emit. Then let us assume that one container is at 80.000 C (add as many zeroes as needed) and the other is at 20.000 C (again add as many zeroes as needed). Is it theoretically possible for a split nanosecond for single photon from the colder 20.000 C container to be emitted to the other hotter container to cause the one container to heat to 80.001 C for example and have the other one drop to 19.999 C for example?
Apparently you have forgotten Dr. Spencer´s “famous” (at least for me) blog:
“Yes, Virginia, Cooler Objects Can Make Warmer Objects Even Warmer Still”
I have not. Before reading it I was completely in agreement with it, but due to a misunderstanding of the title I wrongly criticized Dr. Spencer´s “lack of earnest” … Sorry.
@Roy W. Spencer, Ph. D. says:
February 19, 2012 at 4:18 PM
“Steve, if there is a temperature decrease with height, why would there not be heat flow by conduction (or turbulent mixing) upward? What would keep the upper layers perpetually colder than the lower layers?
I believe that heat flow *would* occur, and the upper atmosphere would have no way of cooling without the ability to emit IR radiation. As a result, the upper atmosphere would warm until there was no longer a vertical temperature gradient from the surface upward.”
Thanks for replying.
I guess I did not make my comment very clear. I agree that the atmosphere (or some components of it) must be able to emit in the IR in order to cool via IR emission. My comment was only about the minimum conditions for convective stability in the atmosphere. The atmosphere does not have to increase in sensible temperature with increasing altitude, or even be constant in sensible temperature with increasing altitude to eliminate convection. The only requirement is that the potential temperature at each altitude (the temperature which an air parcel would reach upon adiabatic descent to the surface) be gradually increase with altitude. This is the condition which yields no convection in the troposphere, independent of other considerations like rate of loss of IR to space.
Claes Johnson says:
February 20, 2012 at 1:00 AM
“Radiative heat transfer is a wave phenomenon of electromagnetics, not a particle phenomenon of photon particles flying like bullets from the Sun to the Earth.”
Can you explain this in more detail?
Let me rephrase the question:
“Are you claiming that downward emitted radiation in the atmosphere cannot travel from the colder atmosphere toward the warmer surface?
If this is true, how does the radiation from the Sun travel through the colder upper atmosphere and reach the warmer surface?
Also, what specifically is your definition of ‘back radiation’?
I take the point that without GHG effects the atmosphere would have almost same temperature all over.
The problem would then be the clouds that could form from the water even without GHG effect. Some moisture might be transported to colder areas (the poles) and condense to clouds. Clouds are able to reflect visible radiation and are almost black to infrared, so they could make sure that the atmosphere radiated some infra red and reflected some back to Earth.
Anyway with a clear atmosphere and emissivity of 1 for incomming and outgoing the average temperature would be 5C. Higher around equator and lower at the poles, with large variations between day and night.
A sky without clouds is an interesting experiment, but no one would see it in reality. No clouds- no rains-no sweet water- no food.
I look forward to hear how the experiments/thoughts go forward.
-Svend
I could not resist to mention this:
Do you know that we live in the best possible climate?
Any change will make it worse, so it must be the best.
I saw it in TheClimateScam.se
Dr. Spencer, Thank You for the recap. I think it’s important to periodically raise our heads from the weeds and recall how we got here. Your ability to make this topic accessible is quite remarkable.
Just to be fair, I don’t think the IPCC “…thinks the sky’s the limit.” My reading of the IPCC report is that they believe that the AGW affect Is small but very significant, with a one in twenty chance they are wrong. My reading of your statements (not necessarily your intent) is that you believe the affects are smaller by fifty to eighty percent and not very significant. JP
Roy,
I agree with much of what you say, but have some basic points of disagreement on specific statements. The first is the blanket statement. If you put a blanket on, you will be warmer than without (I am assuming on a live human, not a passive object). If you put more blankets on, you will be even warmer due to slowed heat loss. If the body is putting out a constant amount of power, and not decreasing as as it warms, the exit layer of the blanket will be the same temperature as for just one blanket, not cooler, as the final power loss to the air will be the same (assuming equilibrium, not transient response). This is also true for greenhouse effects in the atmosphere. The outgoing average layer where radiation goes to space will be the same effective temperature as no greenhouse effect whatever the surface temperature is (remember the energy is in balance for steady state conditions). The increase in temperature thus comes from raising the average altitude of outgoing radiation (at the same temperature), and the lapse rate for the additional altitude (potential temperature) supplies the added temperature. You are totally correct that back radiation does not heat the average surface (It can warm it locally at night or under any condition where the ground is colder than the air above it. However, only the air warmer than the ground adds to heating the ground, even though some radiation comes from colder altitudes. Radiation from colder altitudes slows cooling, but does not heat). Back radiation is only the result of radiation insulation causing the radiation location to move to higher altitude, and only net radiation obeys the second law.
I’m beginning to think that thermodynamics is like a religion. Either you have studied it and believe in it, or you haven’t and are doomed to spout eternal nonsense. (Is there a circle in hell for that?) Claes would have us believe that an atom knows which way is up, so it can stop itself from emitting a photon in a down direction, which is an awful sin.
Roy, I hereby join this handwaving contest with a wave in your direction; there very definitely is a greenhouse effect and it very definitely raises the surface temperature.
While I am at it, space very definitely has a temperature.
I have put up a comment on Roy’s claim that the outside of a layer of blankets will cool if more layers are put on:
http://claesjohnson.blogspot.com/2012/02/can-spencer-describe-greenhouse-effect.html
Dr. Spencer, with all due respect,
The GHE hypothesis has a flaw. Ironically enough it is an accounting flaw rather than a scientific flaw. I know since you have worked in this field for your entire career you are reluctant to admit this flaw may exist. However, I believe it does. You are missing the simple fact that the energy returning to the surface as “backradiation” is not “extra energy” entering the system. It is simply energy that is making another pass through the system after already passing once (from the Sun to the surface to the atmosphere and then back to the surface) through the system. As it passes through the system it leaves cooling in its wake. Simply stated; all (significant) energy input to the system comes from the Sun, this energy input bounces back and forth between the surface and the gases (which act only as “graybody“ re-radiators of energy, not “blackbody” SOURCES of energy) while it quickly dissipates to space.
These extra “bounces” add a delay to the transit time simply because the energy makes more trips through the system. More trips at the same “speed of heat” equals a delay. This is totally different from the effect demonstrated by typical thermal insulation which does indeed slow the flow of heat, this is why the furnace in a well insulated house has to “fill” the house with heat less frequently which is of course less costly.
Unfortunately, I think you are still mistaking the “rate of heat generation” with the “speed of heat flow”.
Just one little correction if I might be so bold, you wrote;
“So, if you continuously pump a certain number of Watts per sq. meter into a highly insulated system, the interior temperature can rise so high that the resulting infrared emission at the high temperature in Watts per sq. meter exceeds the rate of energy input into the system.”
With all due respect this is WRONG. As an engineer that has designed successful thermal control systems I will state with no reservations at all that; YOU CANNOT EVER (NO WAY, NO HOW, NOT NOW, NOT EVER) CAUSE ENERGY EMISSIONS (IR, MICROWAVE, VISIBLE, X-RAY, AUDIBLE, OR ANY OTHER TYPE OF ENERGY YOU CHOSE) THAT EXCEED THE ENERGY INPUT TO THE SYSTEM.
I am sorry, but the GHE is a hoax. I am also sorry that you find the GHE something to be cherished.
As a thought experiment I suggest the following;
IF the GHE exists as postulated (i.e. it allows for the CORRECT calculation of “net energy gains”) why is it that no engineer has yet to apply it to solve any real world problem? After all this “effect” has supposedly existed for a century or more, other physical effects have been quickly exploited by engineers after they were discovered, for example the Peltier effect which is used to precisely control the temperature of electronic devices.
I see several possibilities;
1) Engineers are dumber than climate scientists. Seems doubtful, some are probably dumber, but a bet at least a few are smarter.
2) There is a dearth of problems to solve. Seems doubtful, there always seems to be a wealth of real problems to solve.
3) The GHE does not cause the claimed effects (i.e. a higher equilibrium temperature).
I’m betting on door number 3 myself.
I also suggest another thought experiment, please start with 1 millijoule (not mW, but mJ) of 6500 K sunlight arriving at the surface. Carefully follow it though the system, while noting the alternative warming and cooling events that happen as it travels though the system. It quickly becomes apparent that all that occurs is multiple sequential warming / cooling / warming / cooling …. events. Since these warming events occur with finite time delays between them YOU CANNOT ADD THEM TOGETHER and get the correct answer. See my initial text about the accounting error present in the GHE hypothesis.
Would you add the sunlight from Monday to the sunlight from Tuesday and claim that the sunlight on Wednesday will be twice as bright ??????????
As an aside, as an engineer I do not “cherish” any physical law or hypothesis, I just note which are dependable (the laws of Thermodynamics, Ohm’s law, Snell’s Law, etc) and which are questionable. The GHE hypothesis is currently in the “questionable” category. And given the current observations (including some very well done ones by yourself and co-contributors) I don’t see this changing anytime soon.
Oh, BTW, did you know that agricultural greenhouses are often constructed with plastic films that TRANSMIT IR radiation. And they still concentrate heat by the restriction of convection, and thereby deprive the surrounding environment of heat that would normally flow about via convection. Perhaps that’s a third thought
experiment.
Cheers, Kevin.
You seem to claim that the model violate the 1st law.
Can you show this more explicit so everybody can see it?
/Mike
You need to use the Stefan Boltzmann equation to arrive at the final temperature of each body where a warm (heated) body is next to a colder body. However for any particular instant you can add/subtract the energy flows to arrive at the net flow, but because the energy flow changes the temperature of the two bodies, the flow equation will change in the next instant. The S-B equation calculates the final resting temperatures of the two bodies.
Although I have always understood the theory of back radiation, the clincher and “eureka moment” for me was when somebody told me about the microbolometer thermal imager such as the one being sold in this link:
http://www.instrumart.com/products/31016/fluke-ti32-thermal-imager
This is a handheld, UNCOOLED, thermal imager that can detect photons landing on its sensor having travelled from objects that are between -20°C and +600°C in temperature (yes that is MINUS 20°C). A very large part of that range is a lot colder than the imager’s sensor itself. How could that be possible if IR radiation is unable to travel from a cold object to a warmer one?
This imager can only exist if photons can travel from cold to hot!
QED.
Somebody here was arguing that electromagnetic radiation is a wave not a particle. This was an argument that was settled over 80 years ago at the time when the rules of Quantum Mechanics were being discovered. These show that electromagnetism, for instance light, behaves according to the laws of BOTH particle physics AND wave physics, depending on whether you are looking for particles or waves. Anybody who is confused by that statement needs to do Quantum Mechanics 101!
Raising the effective radiating height involves increasing the rate of energy flow through the entire system. Convection goes higher carrying more energy out of the system at a faster rate.
If that height rises as a result of more energy flowing through the system such as from increased solar input then one will see greater total energy content within the system at any given time leading to a higher surface temperature AND a higher effective radiating height.
But what if one sees an increase in the effective radiating height WITHOUT any increase in solar input so that there is no more energy content within the system ?
In that case energy out would exceed energy in and the system would get colder.
As far as GHGs are concerned AGW radiative theory suggests that an increase in GHGs causes a rise in the effective radiating height (let’s assume that to be right) but in that situation no more energy is being added to the system from the sun so in theory that should cause overall cooling due to a decline in total system energy content because outward flow is greater but inward flow is not.
One can get around that by accepting that, due to their downward radiating, GHGs would (possibly) delay the exit of energy from the system so that would offset the additional cooling that would otherwise result from a rise in the effective radiating height.
BUT that just gets us back to where we were before, with the same surface temperature. because the faster throughput of energy via the raised effective radiating height offsets the delay in energy transmission caused by the downward radiation from more GHGs. We have changed the environmental lapse rate below the tropopause but not the dry adiabatic lapse rate which applies to the whole system from surface to space. There has been no change in total system energy content because a speeding up in one part of the system has been offset by a slowdown in another part.
To get a higher surface temperature as well as a raised effective radiating height one needs to increase total system energy throughput AND content. That results in a higher atmosphere with greater volume AND a higher surface temperature.
More GHGS do not achieve that. They simply redistribute the energy that is already available and so if the volume of the atmosphere increases from a rise in the effective radiating height then the environmental lapse rate changes for a section of the atmosphere but not the dry adiabatic lapse rate for the whole system so that surface temperature (and total system energy content) stays the same.
amsu temp. data 400mb -36.6 c 2012 versis -35.7 c 2010
600mb -21.3 c 2012 versus -20.5 c 2010
I say substancial cooling.
For Mike at 02/22/2012;
Unfortunately the “reply” function does not work for me, probably some computer security setting on my end. So here is my reply;
For Mike at 02/22/2012;
I suggest that you try the thought experiment I suggest. Accurately follow 1 millijoule of energy through the system, be sure to keep a careful count of the “warmings” and “coolings” involved. Also note that the transit time for IR radiation to travel all the way to the top of the atmosphere is a few milliseconds,speed of light I think they call it.
I probably cannot convince you of the flaw in the GHE hypothesis, but you may convince yourself.
Cheers, Kevin.
We need to get away from the idea that no work is being done where gravity acts on a gas. Roy has made a big mistake in saying that there is a once and for all compression with no work done thereafter. Lots of other highly qualified scientists say just that.
Gas molecules vibrate a lot, moving in ALL directions, by virtue of their kinetic energy which is why they are in gaseous form and not a solid.
Adding solar energy is what makes them zip about to form a gas in the first place and the more solar input the more they zip about.
The thing is though, that every time they move in a horizontal or vertical plane that movement is against the force of gravity which constantly seeks to pull the molecules down to the surface.
The very fact that the kinetic energy is being resisted by the downward pull of gravity from moment to moment means that work is being done constantly.The force of gravity shortens the upward or sideways path of the movement of each molecule that is caused by the kinetic energy present within it and in so far as the length of the path for each vibration is shortened the kinetic energy is converted to IR which registers as heat on temperature sensors.
The power source is the solar input. Switch it off and gravity succeeds in pulling down all the molecules so that the gas forms a solid on the surface once more.
The sun adds the necessary kinetic energy, work is done as gravity opposes it and infra red heat energy becomes highest where gravity has placed most molecules available to participate in the process, at the surface.
So, at that point we have solar input, the gravitational restraining force and the surface temperature all in balance, change any one of them and the point of equilibrium changes as per the Gas Laws.
However, on a planet with an open sky there is also volume to consider.
Volume will be related directly to the total system energy content.
As soon as one changes system energy content by however small an amount the volume will change instantly to keep the other numbers the same UNLESS one also alters the strength of the gravitational field AND/OR the level of solar input. Those two factors will change the equilibrium temperature because they increase the total amount of interaction going on between gravity and insolation.
GHGs alter system energy content a fraction so the volume of the atmosphere changes by a fraction but because there is no increase in gravitational field and no increase in solar input then the change in atmospheric volume instantly cancels the effect of the GHGs on surface temperature by shifting the entire atmosphere upward leaving less molecules near the surface to participate in the pressure/ solar interaction.
The difference being that GHGs only act on timing of the throughput of energy and NOT on the total amount of interaction between gravity and insolation.
GHGs slow down energy loss to space but the increase in atmospheric volume simply dissipates it instantly and in the process the global circulation of the air shifts a miniscule fraction as a result of the increased volume of the atmosphere.
The same thing happens in response to ANY change other than an increased gravitational field or increased solar input.
Hence the Venus/Earth observations and the recent paper by Nikolv and Zeller
I forgot to mention that increased atmospheric mass changes the equilibrium temperature too but GHGs don’t do much in that direction.
Oh dear, I think I gave the impression that I think gravity performs work.
I will reword it to remove that impression.
Stephen Wilde says:
February 22, 2012 at 6:29 AM
“Raising the effective radiating height involves increasing the rate of energy flow through the entire system. Convection goes higher carrying more energy out of the system at a faster rate.”
Stephen,
NO! Raising the effective radiating height has no effect on the rate of energy flow through the system. Solar energy in is BALANCED by radiation out when the system is in balance, whatever the altitude of outgoing radiation. The only result of raising the altitude is that more of the energy is transported up to the outgoing level by convection, and less by radiation. The lapse rate is the same for both cases (-g/Cp), and the heating comes from pining the absolute temperature level of the lapse rate at a higher altitude.
Leonard,
I have noticed previously that you do not distinguish between the environmental lapse rate which is determined by the composition and circulation of the atmosphere and the dry adiabatic lapse rate which is determined by pressure and solar input alone.
Furthermore, you accept that raising the emitting altitude causes more convection which will obviously move energy faster from surface to tropopause which is exactly the point.
If GHGs do indeed (debateable in itself) seek to increase the surface temperature via downward radiation the increased upward convection will negate the effect on surface temperature.
The outcome is of course a continuing balance at the top of the atmosphere where solar energy in is balanced by radiation out.
Simply put, if GHGs increase the radiation buzzing about in the atmosphere the higher emitting altitude and deeper convection will negate any effect on surface temperature.
As you say, extra convection will occur at the expense of the extra radiation that WOULD HAVE been necessary if the GHGs did actually succeeed in warming the surface.
The slope of the environmental lapse rate from surface to tropopause will change a fraction but the underlying dry adiabatic lapse rate from surface to top of atmosphere will continue to be approximately maintained by the system as a whole.
This is my revised account having removed the potential for misunderstanding regarding the contribution of gravity:
We need to get away from the idea that no work is being done when a gas which is receiving solar energy is situated within a gravitational field. Roy Spencer has made a big mistake in saying that there is a once and for all compression with no work done thereafter. Lots of other highly qualified scientists say just that.
They seem to forget that molecules of gas that are receiving solar energy vibrate, moving in ALL directions, by virtue of their kinetic energy which is why they are in gaseous form and not a solid.
Adding solar energy is what makes them zip about to form a gas in the first place and the more solar input the more they zip about.
The power source is the solar input. Switch it off and gravity succeeds in pulling down all the molecules so that the gas forms a solid on the surface once more.
The sun adds the necessary power, work is done as the molecules vibrate and infrared heat energy becomes highest where gravity has placed most molecules available to participate in the process, at the surface. The weight of the whole atmosphere places greatest pressure and greatest molecular density at the surface.
So, at that point we have solar input,surface pressure and surface temperature all in balance. Change any one of them and the point of equilibrium changes as per the Gas Laws.
However, on a planet with an open sky there is also the volume of the atmosphere to consider. That volume will be related directly to the total system energy content.
As soon as one changes system energy content by however small an amount the volume of the atmosphere will change instantly to keep the other numbers the same UNLESS one also alters the pressure at the surface AND/OR the level of solar input. Those two factors will change the equilibrium temperature because they increase the total amount of interaction going on between air molecules and insolation at the surface.
GHGs alter system energy content a fraction so the volume of the atmosphere changes by a fraction but because there is no increase in surface pressure and no increase in solar input then the change in atmospheric volume instantly cancels the effect of the GHGs on surface temperature by shifting the entire atmosphere upward leaving less molecules near the surface to participate in the interaction with solar energy.
The difference is that GHGs only affect the timing and location of the throughput of energy and NOT the total amount of interaction between air molecules and solar energy.
GHGs slow down energy loss to space but the increase in atmospheric volume simply dissipates it instantly and in the process the global circulation of the air shifts a miniscule fraction as a result of the increased volume of the atmosphere.
The same thing happens in response to ANY change other than increased surface pressure or increased solar input.
Hence the Venus/Earth observations and the curve fit shown by Nikolov and Zeller in their recent paper.
Stephen Wilde says:
February 23, 2012 at 4:39 PM
Stephen,
The dry adiabatic lapse rate does not depend on solar insolation at all, only gravity and Cp. On the average the lapse rate is the adiabatic lapse rate as modified by water vapor condensation effects (the wet lapse rate). The dry lapse rate occurs over some areas when water vapor does not condense. The environmental lapse rate is, on average, the actual wet lapse rate, due to the fact that water vapor condenses almost everywhere on our water planet, but it can vary locally due to atmospheric movement and due to day/night and latitude variation. However, the average lapse rate, which requires enough mixing to maintain adiabatic conditions, still only depends on the Earth’s gravity and the effective specific heat of the atmosphere, and the modification due to water vapor condensation. We can argue all day about the fact that if there is not sufficient mixing locally, there can be a lower environmental lapse rate. Earth’s atmosphere is complex and clearly locally varies under clouds, at night, etc. However, I am talking about average conditions. Varying CO2 would mainly change the altitude of outgoing radiation, but may very slightly change the environmental lapse rate, but the main effect is almost certainly the change in altitude. If there were no greenhouse gases other than CO2, and if the concentration change were not huge (so as to not change Cp), the only effect of increasing CO2 would be an altitude change of outgoing radiation, and increased warming resulting as I stated. This is the point I was making.
Leonard,
If the slope of the environmental lapse rate changes then one can have an increase in altitude of outgoing radiation without a change in surface temperature.
My point is that the slope of the dry adiabatic lapse rate is fixed by gravity because the strength of the gravitational field determines Cp.
Solar insolation affects the volume of the atmosphere and therefore the distance that the dry adiabatic lapse rate travels from surface to top of atmosphere. That is what affects surface temperature under S-B.
However, the environmental lapse rate can be anything that is required to prevent the compositional variations within different sections of the vertical atmospheric column from diverging too far from that dry adiabatic lapse rate from surface to space.
If the divergence is too great then the atmosphere is either boiled off to space or freezes on the surface so any planet which fails to configure the atmosphere to comply with S-B from surface to space will never acquire an atmosphere in the first place.
Thus for the Earth the actual pattern up through the atmosphere is actually the shape of a ‘W’ set on its side as you probably know.
So my point is that changes in pressure at the surface or solar input will determine the temperature at the surface as per S-B but changes in the composition of the atmosphere will only alter the slope of the environmental lapse rate in the various levels.
S-B only applies if one takes the surface as a point at or just outside the top of the atmosphere.
Everything going on within the atmosphere between surface and space is governed by the Gas Laws.
As per the Gas Laws the surface temperature is determined by a different set of equations and the outcome is affected by the number of gas molecules per unit of volume at the surface available to react with the incoming solar energy.
So, if the atmopheric height (volume) changes without an increase in atmospheric mass there will be less molecules per unit volume at the surface and a lower temperature at the surface from a given amount of solar input.
Thus if one is applying the Gas Laws more GHGs (if they raise the atmospheric height) will actually reduce the achievable surface temperature which is the opposite effect compared to that expected from the S-B equations.
If GHGs do actually increase the energy content of the atmosphere then the height will rise but the surface temperature will not rise because the Gas Laws will result in a surface cooling sufficient to offset the atmospheric warming for a zero net effect overall.
To get a surface warming under the Gas Laws one must increase solar input, atmospheric mass or the strength of the gravitational field. A compositional change will not do it because that just changes the slope of the environmental lapse rate.
Roy – here’s a different question …
Absorptivity measurements are done with incident visible light, even though it is well known that they drop off rapidly when the source has much lower frequencies.
It is thus totally incorrect to assume high absorptivity for the Earth’s surface when the source is very low frequency radiation from the atmosphere. In fact, the absorptivity has to drop to zero when the temperaure of the source is less than that of the target. Otherwise the Second Law of Thermodynamics would be violated as explained here: http://climate-change-theory.com/RadiationAbsorption.html Please take the trouble to read this webpage before responding, as I can’t retype it all here.
So, how can there be a radiative greenhouse effect when it is thus impossible for a cooler atmosphere to transfer thermal energy to a warmer surface, because, under the circumstances, the absorptivity is zero? If you disagree, show me empirical evidence of high absorptivity of such low frequency radiation.
Stephen Wilde,
I agree that gravity enters into the lapse rate, I stated so. However, I am glad you have found a new law of thermodynamics. I would be curious where you found it, that gravity at Earth’s conditions affect the value of Cp. When I examine thermodynamics, I see only gas composition as affecting the value of Cp at conditions found on Earth. The dry lapse rate is -g/Cp. Condensation changes this to a so called wet lapse rate due to the heat release when water vapor becomes liquid drops. All things being equal (which they may not exactly be), increasing CO2 a small amount, and decreasing the O2 a corresponding amount to make the CO2, has small enough effect on the Cp, that it can be considered constant, and g is constant. The only possible cause in change in lapse rate is the wet effect as long as mixing keeps the atmosphere on average well enough mixed to maintain adiabatic conditions.
Doug,
I read your nonsense. Please note that radiation can ONLY be either reflected or absorbed by a surface. There is no non-reflection rejection due to temperature or anything else. The reflection can be specular (like a mirror), or diffuse (scattering), and the fact of absorption or reflection is well understood by science. Please quit showing that skeptics are full of nonsense.
Roy, you may criticise Claes and the Slayers. I don’t agree with everything in their book, but Claes I can prove to be right both with logical physics argument and empirical results as on the ‘Radiation’ page of my site.
The mistake made by the IPCC et al lies in assuming that absorptivity measurements made with visible light will still apply for much lower frequency radiation from the atmosphere. They don’t, and in fact such absorptivity factors, when the source is cooler than the target, must be zero.
Maybe this solar cooker funnel experiment will help you and others understand better ….
You simply cannot explain what happens to the extra radiation in my funnel experiment from the much larger (though slightly cooler) plate to the smaller one. Clearly far more radiation gets concentrated onto the small plate, yet heat flow must be from hot to cold, ie opposite to net flow.
Net radiative flow has no corresponding physical entity and is a meaningless concept. You cannot add different beams of radiation like you can add forces. Yes there is two-way radiation, but heat only flows one way because only the radiation from hot to cold has any effect. So how does this happen? What physical mechanism is involved? My point is that, in the funnel experiment, you cannot just calculate net radiative flux and assume heat goes in the same direction, because it doesn’t.
So “net radiation” is not a physical mechanism which tells us which direction heat will transfer, or how much will be transferred.
Study the frequency diagram on my Radiation page and note that the distribution for a cooler temperature is always fully contained within that for a warmer temperature.
The effect that radiation from the hotter source has is that the excess over that which can resonate with the cooler one is converted to thermal energy. When radiation resonates like this there is no termal energy left behind and the radiation immediately exits just as if it had been reflected with diffuse reflection, not specular.
Radiation which fits under the curve of the cooler one can resonate either way (hot to cold or cold to hot) because those frequencies are common to hot and cold bodies. Such radiation is scattered and the effect is the same as diffuse reflection. The warmer body can scatter any amount of such energy without its own outward radiation being affected and without receiving any thermal energy from the cooler one.
What happens when the Sun is warming the surface in the morning? The net flow of radiation is into the surface, right? So how could the IPCC models be right in saying extra thermal energy (also from radiation in the same direction) flows from cool atmosphere to warm surface against the Second Law.
The Second Law must apply to every individual “transaction” or radiated beam between any two points. You cannot just say all will be fixed up that evening when net flow is finally outwards. Besides, the energy might come back out by diffusion or evaporation rather than radiation.
There are no two ways about it. Only radiation from hot to cold can transfer thermal energy. That from cold to hot does nothing. The amount transferred is represented by the extra frequencies / extra radiation in the area between the curves because these frequencies (coming from the hot body) are only in its distribution and thus cannot resonate with the cooler body. (The result is the same as SBL calculations in normal situations, but SBL does not give the right answer for a funnel.) In contrast, all the frequencies in the cooler body’s radiation can resonate with the warmer one.
For more detail see the ‘Radiation’ page my website http://climate-change-theory.com and a paper (which I have oompleted) will be available in due course – to be advised.
Doug,
what is your definition of thermal energy?
What is your definition of heat?
“I would be curious where you found it, that gravity at Earth’s conditions affect the value of Cp.”
Whoops, in a hurry I read that as constant pressure instead of specific heat for a constant pressure so scrub that bit.
The rest remains valid though.
“if the atmosphere could not cool from IR radiation, it would warm to the same temperature as the surface. This is an isothermal atmosphere, which is convectively stable, and so all convection would stop.”
I think it must be: “to the warmest temperature of the earth surface” Otherwise would not convection stop.
Above a thin slab of atmosphere cooled by conduction with earth surface, of course
That is a much warmer atmosphere than today……
Roy, Leonard and others
You do all these irrelevant “experiments” when what you should be doing is what I did – an experiment to see if backradiation at night actually warms anything.
Fill two wide necked vacuum flasks with sand or soil. Shield one from backradiation at night and compare the temperatures. I found no difference.
Do experiments on absorptivity where the temperature of the source of the radiation approaches that of the cooler target. Such absorptivity reduces and approaches zero as the temperatures approach. That is the only way the Second Law of Thermodynamics could possibly work for radiation.
Then think about the consequences for the radiative version of the GHE.
Here’s today’s post going on several forums …
Before we consider what “backradiation” contributes, let’s say that at 11am on the Equator on one side of the Earth the Sun is shining and delivering 900 W/m^2 to the surface, of which 300W/m^2 is leaking out again into the atmosphere, let’s say 120W/m^2 by evaporation and diffusion followed by convection, and the remaining 180W/m^2 of it by radiation. So we have a net overall inward flux of 900 – 300 = 600W/m^2, this being 900 – 180 = 720W/m^2 net radiation inwards less 120W/m^2 outwards by other processes, ie 720 – 120 = 600W/m^2.
Let us suppose this overall net 600W/m^2 has warmed the surface by 6 deg.C since dawn.
Now the models make out that, let’s say an extra 150 W/m^2 of backradiation from the cooler atmosphere also does some extra warming. So perhaps the increase in temperature has been an extra 1.5 deg.C making a total of 7.5 deg.C since dawn. After all, there is certainly net radiation into the surface.
Do you really believe this extra 1.5 deg.C of warming from the cold atmosphere would not have been in violation of the Second Law of Thermodynamics?
This surely must be the weakest argument and the most blatant travesty of physics in the whole (radiative) greenhouse conjecture.
Pete said in part, on February 19, 2012 at 12:56 PM:
“CO2 accounts for 0.04% of atmospheric gases, and anthropogenic CO2, according to the IPCC is a fraction of that amount (about 4% of the 0.04%). Please explain how such a rare gas acts as a blanket,”
If not for GHGs, average (more like “root-mean-4th”) world surface temperature would be about 255 K – even
if its albedo would be the same.
CO2 is said to account for 9-26% of this. (Any comments on such a wide range?) Also, there appears to me some
agreement that CO2 change has a close-enough logarhythmic effect on radiation budget change, at a rate of 3.7 W/m^2 per factor-of-2 change (at least when PPMV CO2 is more than something like 100 PPMV).
Meanwhile, CO2 increased about 40% since the Industrial
Revolution began, and most of that increase was when nature was net-*removing* CO2 from the atmosphere.
http://www.tyndall.ac.uk/global-carbon-budget-2010
http://scrippsco2.ucsd.edu/data/flask_co2_and_isotopic/monthly_co2/monthly_mlf.csv
More honest debate is in what feedbacks nature adds to this.
For example, it appears to me that positivity of the cloud albedo feedback requires less water vapor positive feedback than is the case with constant relative humidity.
Possibly, the sum of cloud albedo and water vapor feedbacks is is about equal to the “constant relative humidity figure” for the water vapor feedback alone. And, the lapse rate feedback (negative) gets increasingly negative as increase of GHGs increases the lapse rate – making climate sensitivity *decrease* as GHGs and related warming increases.
Doug Cotton says, Feb. 25, 2012 at 8:22 PM:
“Before we consider what “backradiation” contributes, let’s say that at 11am on the Equator on one side of the Earth the Sun is shining and delivering 900 W/m^2 to the surface, of which 300W/m^2 is leaking out again into the atmosphere, let’s say 120W/m^2 by evaporation and diffusion followed by convection, and the remaining 180W/m^2 of it by radiation. So we have a net overall inward flux of 900 – 300 = 600W/m^2, this being 900 – 180 = 720W/m^2 net radiation inwards less 120W/m^2 outwards by other processes, ie 720 – 120 = 600W/m^2.
Let us suppose this overall net 600W/m^2 has warmed the surface by 6 deg.C since dawn.
Now the models make out that, let’s say an extra 150 W/m^2 of backradiation from the cooler atmosphere also does some extra warming. So perhaps the increase in temperature has been an extra 1.5 deg.C making a total of 7.5 deg.C since dawn. After all, there is certainly net radiation into the surface.
Do you really believe this extra 1.5 deg.C of warming from the cold atmosphere would not have been in violation of the Second Law of Thermodynamics?”
In the case of thermal radiation between two objects, it flows both ways as long as both are warmer than absolute zero. “2nd Law” only requires *net transfer* by thermal radiation between the two objects to be from the warmer one to the colder one.
If the colder one improves its emissivity and its absorption of energy from the warmer one, then the rate of *net transfer* from warm to cold can be decreased. “2nd Law” merely requires this to not be reversed.
A decrease in “downhill flow” of energy, short of reversal, can easily cause a hot object to gain temperature in order to restore output being equal to input. (Where input is combined radiation from variable cooler sources and possibly-constant hotter sources.)
Roy
This is a very strange comment to make when trying to “prove ” that the Second Law is not violated. You wrote But the same objections could be made against many systems which create very high temperatures. You can pump energy into a system at a certain rate, and insulate the system so that it cannot lose heat easily and thus increase temperatures to very high levels.
Let me quote Wikipedia (Second Law ..)
The second law declares the impossibility of machines that generate usable energy from the abundant internal energy of nature by processes called perpetual motion of the second kind.
Any “pumping” up of temperatures in the atmosphere would have to raise the temperature up there to more than the surface temperature at the time before any spontaneous radiation from the atmosphere would warm the surface.
It cannot happen, Roy, and it doesn’t.
And before you come back at me with discussion of “net” radiation, tell me what physical entity you think net radiation actually corresponds to. Are two rays on oppposite sides of the World (day and night) going to have a combined effect? Hardly! Nor would they even if only a metre apart in parrallel with each other.
The only way any effect of radiation in one direction can be altered by radiation in the other direction is via thermal energy addition. This means the energy in each ray has to be converted to thermal energy first. After all, it might exit the surface by evaporation or some other non-radiative process.
Each ray has to be considered as a separate process. So any conversion to thermal energy involving radiation from a cooler atmosphere to a warmer surface violates the Second Law. Other rays in the opposite direction cannot justify the violation.
The reason it does not happen is because the absorptivity of the surface does in fact reduce to zero for radiation coming from a cooler source. Such radiation merely resonates or is “rejected” in some way, just as if it underwent diffuse reflection. Only radiation from hot to cold counts when it comes to anything to do with temperatures of the target.
My funnel experiment proves that his must be the case and that the warmer surface can in fact handle any amount of such radiation without it affecting its own rate of emission or its temperature.
(I give notice that I have submitted a paper on this and do not wish to reveal the explanatory mechanism detailed in that paper at this point for obvious reasons.)
Doug Cotton says in part at February 26, 2012 at 3:02 AM
“The only way any effect of radiation in one direction can be altered by radiation in the other direction is via thermal energy addition. This means the energy in each ray has to be converted to thermal energy first. After all, it might exit the surface by evaporation or some other non-radiative process.”
As soon as a photon is absorbed, its energy is converted to heat. The energy becomes heat before escaping the surface by radiation, evaporative cooling, etc.
“Each ray has to be considered as a separate process. So any conversion to thermal energy involving radiation from a cooler atmosphere to a warmer surface violates the Second Law. Other rays in the opposite direction cannot justify the violation.”
Each ray alone does not carry any data about the temperature of its source. A single 10 micrometer infrared photon does not carry information as to whether its source temperature is 200K or 400K. So, the temperature of the source of that photon does not change a 300K target gaining 2E-20 joule of energy by absorbing that photon.
Here is another example of 2nd Law only requiring net flow to be downhill: A jar filled with helium, and having an electric heating element in its lid. Suppose the temperature of the helium is 300K at the bottom, and 330K at the top. The helium atoms at the top will have 10% more kinetic energy than the ones at the bottom, but only as a whole. Kinetic energy of the atoms or molecules in a small parcel of gas is not the same for each one, but there is a range of individual kinetic energies.
The helium atoms in the bottom of the jar would each have
individual kinetic energies on average 6.9E-26 joule, but over a wide range, with most of them each having kinetic energy in a range of something like 4.6E-26 to 9.2E-26 joule. The ones at the top would have their kinetic energies 10% higher, which would make that correspondingly mostly 5.05E-26 to 10.1E-26 joule. There is a lot of overlap here, so energy transfer by atom collisions is going to flow both upward and downward. The net flow will be downward.
The IPCC models make use of absorptivity measurements for the Earth’s surface which were measured using visible light. But they apply them to far-IR radiation from the atmosphere, even though it is well known that absorptivity reduces very significantly for much lower temperature radiation. This is obviously important when determining the assumed warming effect of radiation from the atmosphere – which, by the way, is assumed to help the Sun with its warming every sunny morning – all quite against the Second Law of Thermodynamics which they think it isn’t because somewhere on the other side of the Earth at night some radiation is turning it all into totally unphysical “net” radiation which cannot be a physical entity. But, never mind, I diverge.
The question is Can someone link me to any empirical measurement of absorptivity by the surface of radiation in the IR bands emitted by the atmosphere?
You’d kinda think the IPCC would have got this part sorted out before spending all that money on the models. So show me where they did – anybody!
Donald L. Klipstein (Jr) February 26, 2012 at 2:34 PM
Any radiation containing the frequencies indicated by a Planck curve has a peak frequency which is proportional to absolute temperature. So there is temperature information in the radiation. Look up Wien’s Displacement Law if you are not familiar with it, and then my ‘Radiation’ page will refute your other points http://climate-change-theory.com
Your helium example involving convection and diffusion is totally irrelevant to calculations involving the radiation between two blackbodies.
I stand by what I have said and you have in no way successfully refuted any of it.
You even talk about conversion to “heat” without realising that would be a violation of the Second Law of Thermodynamics. You do not seem to have a valid concept of how and why radiated thermal energy transfer actually obeys the Second Law. It has nothing to do with net radiation. If it did, a simple funnel focusing radiation could create energy.
Maybe Markus Fitzhenry can explain it better for you, or at least show you I am not alone in what I’m saying http://wattsupwiththat.com/2012/02/26/the-skeptics-case/#comment-905670 My paper on this (already submitted) will be available in due course.
“Even for the same rate of energy input from the sun, the average surface temperature can vary widely depending upon the atmosphere’s ability to restrict the rate of energy loss from the surface, either radiatively or convectively.”
Question arising :
Leave radiation aside for a minute : An atmosphere’s ability to restrict energy loss from the surface convectively is surely a function of the weight of air pressing down on it from above. How can it not be?
In simple terms, the greater the weight of air pressing down on the air at the surface, the more energy it needs to acquire to power convection, and the only way it can acquire that energy is through a build up of heat. This is just like your greenhouse – no? The only essential difference being that, instead of having a roof made of glass, the air at the surface has a “roof” made of the air pressing on it from above which can be lifted once it acquires enough energy.
If this is wrong then I’d be very interested to read your explanation as to why it is wrong.
If it is correct……
Stephen,
For a given mass of atmosphere, the effective thickness (altitude to a small selected fraction of ground pressure) will be affected by the temperature. Thus the solar insolation will affect the temperature. This is not due to the atmosphere being thicker, but the atmosphere is thicker due to the temperature being higher with greater surface heating from the greater insolation (assuming constant composition and mass). Basically you confuse cause and effect. However, all arguments are for a constant solar insolation and varying greenhouse gas. If the greenhouse gases increase (but total mass and Cp are close to constant due to addition being very small portion of total), but at constant solar insolation, the altitude of outgoing radiation is raised due to the greenhouse gases doing the radiating even though they are small part of total composition. Thus their partial pressure is only factor in simplified case. i.e., the greenhouse gas atmosphere is thicker even though the total atmosphere is essentially the same.
Responding to the post of Doug Cotton of February 27, 2012 at 12:07 AM, at http://www.drroyspencer.com/2012/02/more-musings-from-the-greenhouse/#comment-35311.
Doug Cotton writes: “Can someone link me to any empirical measurement of absorptivity by the surface of radiation in the IR bands emitted by the atmosphere?”
A good start to this is to be found in Paltridge, G.W., Platt, C.M.R. (1976), ‘Radiative Processes in Meteorology and Climatology’, Elsevier, Amsterdam, ISBN 0-444-41444-4 on pages 128-136.
I am having a problem with the proverbial ‘lapse rate graph’ from above. I call it proverbial because it showed up in many places. Indeed, graph makes sense, but only qualitatively… the graph says that due to convection temperature aloft would increase dramatically, while temperature near the ground would only increase so slightly. But that is only true if most of the atmospheric IR is emitted from the layers near the ground, by virtue of energy conservation law (outgoing radiation must be equal both with and without convection set in). But that is only true if atmosphere is extremely translucent to IR, so that optical depth of IR photosphere is comparable or larger than its physical depth, which goes contrary to the ‘saturated’ nature of current GH effect as evidenced from low sensitivity. Therefore, I conclude,m that those graphs, while qualitatively are correct, are grossly misleading otherwise. In reality I deem, the curves of with- and without- convection lapse rates would be crossing somewhere in mid-to-high troposphere, around 400-300 mb. Which would mean that surface air temperature in convective case would be MUCH LOWER that in convectionless, and even lower in the case of moist convection. Roughly from the graph this translates to convective cooling underestimated by a factor of two. But that actually matches your words (from long ago) that without convection we would have +70, and with it we have +14, difference of 60K while the graph only shows around 30K at best. Please comment if you think the graph may be ‘adjusted’ to serve warmmongerers.
Food for thought:
There is an unnecessary focus on CO2 which stymies much more relevant research. By proclaiming that the culprit has been found, climatologists have latched onto CO2-hypothesis because they admittedly, don’t know or understand the complex interactions that are responsible for the climate. The greenhouse theory is just so rational for the non-scientists and for the politicians. Even more than 200 infantile computer models have been developed to lend credibility to the CO2 claims by using the curve fitting approach.
While I enjoy the blog very much because of the rationales and the critical thinking that is put forth I don’t think it advance the purpose to establish climatology as a respectable science. I am more inclined to accept the opinion of a scientist who discusses the violation of the two laws of thermodynamics: “Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics” , Version 4.0 (January 6, 2009), by Gerhard Gerlich at http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1161v4.pdf . It appears “The popular greenhouse ideas entertained by the global climatology community are absurd in that they are based upon a falsified scientific foundation that was debunked by modern science.”
So, let’s not over-emphasize and spin our wheels with what in the end might be an unimportant hypothesis. I recommend the recently published book, “Die kalte Sonne” as an additional resource.
Maybe we need the liquid flow meters so that there is a proper use of water resources.
I like this blog its a master peace! Glad I detected this on google.