Guest Post by Willis Eschenbach
I got to thinking about the classical way to measure the very poorly-named “greenhouse effect”, which has nothing to do with greenhouses. To my knowledge, this method of measuring the greenhouse effect was first proposed by Raval and Ramanathan in a 1989 paper yclept “Observational determination of the greenhouse effect“.
Their method, followed up to the present by most everyone including me, is to subtract the upwelling (space-bound) longwave (LW) radiation measured by satellites at the top of the atmosphere (TOA), from the upwelling surface longwave radiation. Or as they describe it in the paper, which was only about the ocean:
” We obtain G by subtracting longwave radiation escaping to space from estimates of the radiation emitted by the ocean surface.”
This measurement is said to represent the amount of upwelling surface radiation absorbed by the atmosphere. This can be expressed either as watts per square meter, or as a percentage or a fraction of the surface emission.
Figure 1 shows this measurement of the all-sky “greenhouse effect” around the world. It shows the amount of energy absorbed by the atmosphere expressed as a fraction of the underlying surface emission.
Figure 1. Atmospheric upwelling longwave (LW) absorption as a fraction of surface longwave emission.
Figure 1a. As in Figure 1. Changes over time of atmospheric longwave (LW) absorption as a fraction of surface longwave emission.
So … what’s not to like?
Today, while pondering a totally different question, I realized that the Ramanathan measurement, while not useless, is also not accurate. There are two issues I see with the measurement.
Other Energy Inputs To The Atmosphere
About 40 W/m2 of upwelling surface longwave goes directly to space. The rest of the ~240 W/m2 of upwelling LW comes from the atmosphere, not the surface.
The first issue with the Ramanathan method is that the atmosphere only gets about two-thirds of its energy flux from absorbed upwelling surface longwave radiation. The other third of its energy flux comes from two totally different sources— 1) solar energy absorbed by the atmosphere, aerosols, and clouds, and 2) latent (evaporative) and sensible (conductive) heat loss from the surface to the atmosphere.
As a result of these other energy fluxes entering and leaving the atmosphere, changes in the top-of-atmosphere (TOA) longwave measured by satellites using the Ramanathan method may merely reflect changes in solar absorption or changes in latent/sensible heat loss. Here’s the total of the other energy going into the atmosphere.
Figure 2. The sum of two other sources of energy fluxes absorbed by the atmosphere.
As you can see, these other sources of atmospheric energy flux vary over time. Part of this additional energy flux is radiated to space, messing with the Ramanathan estimate of the greenhouse effect.
Up Versus Down
The second issue is that the atmosphere radiates in two directions, up and down. However, the ratio between upwelling and downwelling longwave (LW) radiation is not constant. Here is the variation in TOA upwelling longwave due solely to the changing upwelling/downwelling ratio.
Figure 3. Variations in top-of-atmosphere longwave (TOA LW) radiation due solely to the variations in the ratio of atmospheric energy going upwards and downwards.
The variations in these two other energy fluxes, variations that will appear in the amount of energy heading out to space, will cause spurious variations in the Ramanathan greenhouse measurement.
A Better Metric??
Seems like if we considered the TOA LW as a fraction of the total energy entering the atmosphere, rather than as a fraction of upwelling surface LW, it might be more instructive … hang on, never done this … well, dang, this is interesting.
Figure 4. As in Fig. 1a, except comparing the upwelling TOA longwave radiation going to space to total atmospheric energy flux, rather than comparing it just to upwelling surface longwave.
Hmmm … not sure what to say about that. It does seem that the fraction of atmospheric energy flux going out to space hasn’t changed much over the 22-year period of record. And it certainly has not increased by the amount we would expect from the increase in CO2 forcing …
All ideas welcome.
My best wishes to all,
w.
The Usual: Please quote the exact words you are discussing. It avoids a host of misunderstandings.
Story Tip
New Study: ‘Atmospheric CO2 Is Not The Cause Of Climate Change’ … The Next Glaciation Has Begun (notrickszone.com)
I am not sure I understand the final point:
“ It does seem that the fraction of atmospheric energy flux going out to space hasn’t changed much over the 22-year period of record. And it certainly has not increased by the amount we would expect from the increase in CO2 forcing”
Firstly your figure 4 does not appear to show anything other than conservation of energy, i.e. energy out (TOA long wave flux) must equal energy in (Total Atmospheric Energy Flux) so you
would expect it to be roughly constant which it is. Secondly I would expect that the effect of adding CO2 to the atmosphere would result in a decrease in the ratio since more energy is stored in the atmosphere while the earth heats up and the the ratio would increase again once the earth is back in thermal equilibrium. So where does you red line in figure 4 come from?
Lastly the amount of energy needed to raise temperature of the earth by the measured amount corresponds to a few millionths of the incoming solar flux which corresponds to an increase 1000 times smaller than the scale you are showing. So any change in the TOA due to a change in the greenhouse effect would not be visible in your graph.
Willis,
Nice article.
I would like to propose a scenario about downward radiation. GHG theory says that will raise the temperature of the earth. Planck say no it won’t. Downward radiation is a surety, however, there can be no net flow of heat as long as the surface is warmer than the atmosphere. What can happen needs a gradient to explain. At best, one can expect equilibrium radiation, i.e., the atmosphere is at the same temperature as the surface. This doesn’t mean the surface warms, it means it remains at that temperature. If the atmosphere is cooler than the surface, what happens is that the gradient of heat loss by the surface is reduced. That does mean the surface temperature goes up, is simply means that it stays at a given temperature longer. In other words, the differential is smaller, but never negative, since that would imply the atmosphere is raising the surface temperature.
Why is this important? Because averages hide things. You can’t see the details of heat transfer by averaging over a period of time. It is why thermodynamics in college requires a basis in calculus.
Your article is a good basis for closer study of what occurs when the sun is shining and what occurs when it sets.
To stay at any temperature, the surface needs to balance all absorbed fluxes of radiation with emitted radiation. If the gradient is lowered that means that the surface is absorbing more radiation than it is emitting, and to tend back toward equilibrium it must emit more radiation, which it can only do by warming up.
Just think conceptually about the exchanges. If the surface receives 5 units of energy from the sun per second and 5 units of energy from the atmosphere per second, it must emit 10 units of energy upward, so it must, by the Stefan-Boltzmann law, be at a temperature high enough to enable this. If the atmosphere starts to send 6 units of energy per second back to the surface, the surface is now absorbing 11 units of energy per second, but emitting 10. It must warm up until it is at a temperature, again dictated by the Stefan-Boltzmann law, that enables this flux. At no time in this process was it necessary for the gradient to reverse in order to force warming at the surface.
You are dealing with a three body system where the source can not see (or only partially see) the atmosphere. Therefore the surface and atmosphere become an isolated two body system.
In an ideal world, the S/B equation for radiation holds. There is no net radiation, i.e., heat transfer between the two bodies at equilibrium.
Since the surface is the source for the atmosphere, the atmosphere can not raise the temperature of the source beyond that of the source. If it could, the process would continue forever with both getting hotter and hotter.
Before you inject that the atmosphere absorbs some of the suns readiation, that needs to be added to the suns radiation.
Get Max Planck’s book on the Theory of Heat Radiation. When you learn what compensation is you will understand. Briefly, assuming ideal bodies:
• the sun heats the surface until 100 is radiated constantly
• the atmosphere absorbs 50 and radiates it back to the surface
• the surface is still radiating at 100, but the new 50 means the gradient is reduced
• the atmosphere begins radiating 60
• …
• this continues until radiative equilibrium is reached.
There are a lot of things involved that are not ideal. The mass of the surface and the atmosphere are vastly different. Some of the heat absorbed by the surface is conducted into the earth for later radiation. It is why gradients involving time are needed to address it correctly and why averages hide substantial heat flows in the system. Don’t forget that exponentials are involved because of T⁴ are involved.
• the sun heats the surface until 100 is radiated constantly
• the atmosphere absorbs 50 and radiates it back to the surface
• the surface is still radiating at 100, but the new 50 means the gradient is reduced
• the atmosphere begins radiating 60
• …
In the first two bullets, the surface needs to balance 150 units of incoming radiation, which it must do by warming. If we make a simplifying assumption that the atmosphere absorbs 100% of outgoing radiation, the atmosphere is returning 50 units downward and losing 50 units to space every second. The surface must now balance 150 units of incoming radiation per second. When it warms enough to emit 150 units of radiation per second, the atmosphere will be returning 75 units downward and emitting 75 units to space, and so on and so forth until the atmosphere is emitting 100 units upward and 100 units downward every second, and the surface must emit 200 units upward to balance the sun and atmosphere.
At no point is the atmosphere ever emitting a higher flux than the surface.
You didn’t read Planck did you?
Your comment is a non-response and less than useless.
From Planck:
“”””Any change in the energy distribution consists of a passage of energy from one monochromatic radiation into another, and, if the temperature of the first radiation is higher, the energy transformation causes an increase of the total entropy and is hence possible in nature without compensation; on the other hand, if the temperature of the second radiation is higher, the total entropy decreases and therefore the change is impossible in nature, unless compensation occurs simultaneously, just as is the case with the transfer of heat between two bodies of different temperatures.””””
“”””For example, if we let the rays emitted by the body fall back on it, say by suitable reflection, the body, while again absorbing these rays, will necessarily be at the same time emitting new rays, and this is the compensation required by the second principle.””””
You need to show how your assertion works. If 150 is absorbed then the atmosphere will receive 150, which it radiates 60 back. That is an infinite series of an increase in temperature.
Work it out on paper. Where does the infinite series increase stop?
Have you ever created gradients based in time?
“”””24. We shall now apply the laws enunciated in the last chapter to the special case of thermodynamic equilibrium, and hence we begin our consideration by stating a certain consequence of the second principle of thermodynamics: A system of bodies of arbitrary nature, shape, and position which is at rest and is surrounded by a rigid cover impermeable to heat will, no matter what its initial state may be, pass in the course of time into a permanent state, in which the temperature of all bodies of the system is the same. This is the state of thermodynamic equilibrium, in which the entropy of the system has the maximum value compatible with the total energy of the system as fixed by the initial conditions. This state being reached, no further increase in entropy is possible.””””
———————-
The rigid cover doesn’t allow anything outside the system to come in. It doesn’t mean you can’t have a source and body, i.e., surface and atmosphere. Your proposition sounds reasonable at first blush, but it requires an infinite series to describe the increase. You need to prove that isn’t the case.
It’s not, and I already demonstrated that above, but I’ll try to explain it more slowly for you. For the following, imagine that at t=0 we “switch on” the sun. Each step occurs in chronological sequence after the sun’s rays are first emitted.
The sun emits 100 units.
The ground absorbs 100 units.
The ground emits 100 units.
The atmosphere absorbs 100 units.
The atmosphere emits 50 units up, 50 units down.
The ground absorbs 100 units + 50 units
The ground emits 150 units
The atmosphere absorbs 150 units.
The atmosphere emits 75 units up, 75 units down.
The ground absorbs 100 units + 75 units
The atmosphere absorbs 175 units.
The atmosphere emits 87.5 units up, 87.5 units down.
The grounds absorbs 100 units + 87.5 units.
The ground emits 187.5 units.
The atmosphere absorbs 187.5 units.
The atmosphere emits 93.75 units up, 93.75 units down.
Have you started to detect a pattern? At each interval, the atmosphere is emitting a smaller and smaller increased fraction downward. Carry on.
The ground absorbs 100 units + 93.75 units.
The ground emits 193.75 units.
The atmosphere absorbs 193.75 units.
The atmosphere emits 96.875 units up, 96.875 units down.
The ground absorbs 100 units + 96.875 units.
As time approaches infinity, the emittance from the atmosphere approaches 100 units up, 100 units down. As time approaches infinity, the emittance from the ground approaches 200 units up. If you’re still struggling, follow your own advice and study some calculus.
“”””The sun emits 100 units.
The ground absorbs 100 units.
The atmosphere absorbs 100 units.
The atmosphere emits 50 units up, 50 units down.””””
There is your first mistake.
From Planck:
“”””Nevertheless, we shall as a rule be able to treat the phenomenon of emission as if all points of the volume-element dτ took part in the emission in a uniform manner, thereby greatly simplifying our calculation. Every point of dτ will then be the vertex of a pencil of rays diverging in all directions.””””
As a proof. How does an infrared thermometer deduce the temperature of an object if you must read all the sides to get an answer?
If I take my torch and heat a cube can I read just one side with my IR thermometer to get the whole blocks exact temperature?
Show a reference that describes how the surface can absorb 100 then emit 100 in one direction but the atmosphere works differently.
We measure the flux as Watts per meter square. A layer of the atmosphere has the same surface area on the top and bottom sides. The outgoing flux must therefore be exactly half of the received flux in our example since the atmosphere emits upward and downward. (same amount of energy per second spread over twice the surface area).
The surface emits only upward because radiation does not pass through the solid earth, the atmosphere emits uniformly in all directions but only the components normal to the surface do not cancel in a given layer.
“”””The outgoing flux must therefore be exactly half of the received flux in our example since the atmosphere emits upward and downward. (same amount of energy per second spread over twice the surface area).”””
“”””The surface emits only upward because radiation does not pass through the solid earth, the atmosphere emits uniformly in all directions but only the components normal to the surface do not cancel in a given layer.””””
Why does the earth not absorb the downward radiation it emits?
Why can you use an IR thermometer aimed at one side of a cube to measure its temperature?
What?
You really don’t know much about EM radiation do you? Get Planck’s book, study emmision and entropy, memorize it.
I’ve given you references. All you’ve done is make assertions with no reference.
Explain with references why the surface can not absorb EM radiation at CO2’s frequencies that is radiated by the surface.
You must think that the sun only heats the very top layer of molecules only on the surface.
Because the direction of propagation is outward, away from the surface. So it isn’t possible for the surface to intercept radiation that is moving away from it. That isn’t how space works.
If you’re asking if solid matter below the skin layer of the earth’s surface absorbs incoming radiation, it does, but most radiation is absorbed within a very short distance of the skin.
“””If you’re asking if solid matter below the skin layer of the earth’s surface absorbs incoming radiation, it does, but most radiation is absorbed within a very short distance of the skin.””””
Doesn’t really matter if it’s only a short distance, it means radiation can be directed downward at the surface. So you assertion that every bit of energy is directed upward is incorrect. The surface radiates in both direction equally, as Planck says.
Why won’t you answer my question about IR thermometers? How can they work out if absorbed energy is split between “sides”.
You may not realize it, but your lack of knowledge appears when you talk about half up and half down. What about sideways?
Is there 0 radiates sideways?
Do you think CO2 only knows to radiate either directly against or directly with gravity?
I urge you to get Planck’s book and study it.
Are you trying to say that the surface can emit radiation inward, toward the center of the planet? The movement of energy inward occurs via conduction.
Your question is ill-posed. You can’t measure the temperatue of a small object heated on one side by pointing an IR thermometer at a single side, because not all sides of the object will attain the same temperature. The side exposed to the heat source will be warmer. How much warmer depends on the length of time the object has been exposed to the heat and the thermal conductivity of the material the object is comprised of.
Of course, I already addressed this, but perhaps your lack of knowledge prevented you from recognizing that. To reiterate: the atmosphere emits uniformly in all directions but only the components normal to the surface do not cancel in a given layer. The atmosphere does not know to radiate up and down, but the movement of energy on the whole is only up and down (if one Joules goes to the right and one Joule goes to the left, zero Joules have moved).
Dancing fool you are.
Let’s do this. A 1m x 1m x 1m cube is heated in my forge to a temperature of ~573K throughout. It is glowing all over. Does it radiate ~6000/6 sides = ~1000 W/m^2 per side?
Now how about a 1m x 1m x1m of CO2 that absorbs 100 W/m^2. Does it radiate ~100 / 6 sides = ~16 W/m^2 per side?
A blackbody cube heated evenly on all sides to a temperature of 573 K will radiate with an intensity of 6000 W’m^2 – so each square meter of surface area will emit 6000 Joules every second.
But of course the atmosphere is not a cube, each layer is an infinitesimally thin plane. And it is not heated on all sides, but only from terrestrial rays from below. So if you take a 1 square meter slice of a layer of the atmosphere, it is not receiving 100 W’m^2 from above and 100W/m^2 from below (so a total absorbed flux of 100W/m^2), it is receiving an absorbed flux of 100W/m^2 from below, so the top square meter of surface area has a flux of 0W/m^2. The flux per square meter of surface area is thus 50 W/m^2. That is, every second, 100 Joules are absorbed by the layer, not 200 Joules.
“”””To reiterate: the atmosphere emits uniformly in all directions but only the components normal to the surface do not cancel in a given layer.””””
What a joke
So it emits 50 W/m^2 in all directions? How can that be.
Because every bit of the layer in the lateral is a uniform temperature, so every bit is emitting and receiving the same flux, so there is never a net flux. Above the layer emits to space (in our simple single layer model), and below it emits to the surface. It receives no flux from above, only from the surface, so the upward and downward fluxes must be equal to balance the absorbed flux from below. But the upward flux must balance the incoming solar flux.
It’s balances all the way down.
Balance has nothing to do with it. If you snip out a small bit of the layer is it emitting the same in all directions?
Your insistence on “balance” just means if you snip out a cube, dτ as Planck calls it, you would have to divide the 100 by any number of directions. Let’s say 6, if it’s a cube.
Yes, but 4 of the six faces have no net inflow or outflow, so the remaining two faces (upper and under sides) must balance the inflow from the ground.
If there is no balance between incoming and outgoing fluxes, the temperature of the layer will change.
“”””The outgoing flux must therefore be exactly half of the received flux in our example since the atmosphere emits upward and downward. (same amount of energy per second spread over twice the surface area).”””
“”””The surface emits only upward because radiation does not pass through the solid earth, the atmosphere emits uniformly in all directions but only the components normal to the surface do not cancel in a given layer.””””
Why does the earth not absorb the downward radiation it emits?
Why can you use an IR thermometer aimed at one side of a cube to measure its temperature?
Do you not believe the post from Planck? Refute him if you dare!
It is fully when AlanJ gives you a negative for the crime of QUOTING Planck.
Haw Haw Haw……
Funny…. not fully
When is the edit function going to be fixed it works great at Jo Nova where she uses a 5 min EDIT countdown right there in the posted comment area.
You know when I read it I read it as funny. Funny how the brain works!
Alan,
Same question I asked Jim, above. Do you agree with this?
https://wattsupwiththat.com/2009/11/17/the-steel-greenhouse/
Yes, from a quick reading it seems to be consistent with my understanding.
AlanJ, that “steel greenhouse” is based on a fundamental inability to grasp the difference between “energy” and “power”, and that radiation is an energy phenomenon, not a power phenomenon. It will confuse you mightily, because it was developed by a very confused fisherman, not a physicist.
Jim,
Do you agree with this?
https://wattsupwiththat.com/2009/11/17/the-steel-greenhouse/
Not really.
First, it is as Willis says a tinker toy model. It uses averages which won’t give the full picture. IOW, the energy received at zenith is much more than the average. T^4 makes a difference.
Second, it adds reflective energy to the original energy. This doesn’t happen. If it did, as the article said, then the outer shell would be subjected to 480 which would be sent back, and since it is additive, would result in even more. There would never be equilibrium. Planck and S/Bexplains that the flows offset until temps and radiation reach equilibrium. Planck calls it compensation.
Lastly, heat storage plays a part. The surface stores a lot for later release thereby upsetting instaneous radiation. The ground temperature at various times throughout the day changes a lot.
Averages do hide what is happening based on small increments of time. Again T^4 rules.
My thermodynamics professors would be appalled at not setting all the gradients based on time and using calculus to analyze the system based upon time, and boundaries such as when the sun rises and sets.
‘If it did, as the article said, then the outer shell would be subjected to 480 which would be sent back, and since it is additive, would result in even more. There would never be equilibrium.’
I respectfully disagree. To simplify, without a shell, the source emits ‘w’ into space. With the shell, the combined source and shell still sends w into space. The only difference is that the surface of the source now emits 2w to the shell, which emits w to apace and w back to the source. I know it’s not the greatest example, but I’ve personally seen electrical equipment that was not allowed to radiate properly fail from heat build up.
“”””I know it’s not the greatest example, but I’ve personally seen electrical equipment that was not allowed to radiate properly fail from heat build up.””””
Different deal. That is heat trapped inside a source. It isn’t really different than a resistor. It really doesn’t apply to energy from back radiation.
S/B requires assumptions but assuming ideal conditions, it describes radiation between two bodies very well. A cold body will warm until the two radiations are equal. At that point there is no further exchange of heat.
‘…it describes radiation between two bodies very well. A cold body will warm until the two radiations are equal. At that point there is no further exchange of heat.’
Except one of the bodies has a constant source of heat, which it constantly radiates towards the second body, as well as towards the background of space. Similarly, the second body not only radiates to space, but also to the first body. The two-body system will reach equilibrium when it emits the same energy to space as it received from the heat source. It does not endlessly ramp up or runaway.
Btw, I don’t know who’s casting the downvotes, but I wish they’d knock it off.
One final thought, I think we’re both fans of Pat Frank. I don’t see anything in the following quote that seems to dispel the concept of back radiation:
“The radiant energy is absorbed (by CO₂) and then lost by collisional decay. Right up to the stratosphere, 15 μ vibrationally excited CO₂ decays by collision, not re-radiation.
The energy lost to collision is then dispersed into the KE of the atmospheric gases and thereby becomes one with the overall black body radiation field. Then, it gets radiated away into space, but across all the TOA BB wavelengths.
There isn’t any evidence at all that our CO₂ emissions have contributed diddly to warm the climate. Supposing otherwise is just that: supposition. Observationally unsupported. Theoretically invisible. Presently indistinguishable from zero.”
I do think CO2 can thermalize N2/O2. How much ? The mass of CO2 vs rest of the atmosphere is so small I don’t think it can be much.
“Therefore the surface and atmosphere become an isolated two body system.”
Nonsense!
An isolated system is one where neither energy nor matter cross the system boundaries. Neither the Earth’s atmosphere nor its surface fit that definition.
Assuming the atmosphere absorbs no SW radiation from the sun. Does the energy source heating the surface really matter. Could it be nuclear heat from the core? Could it be friction from plate movement? Maybe Morlocks burning fossil fuels? What happens is that the surface becomes a constant source. The source of energy just happens to be remote. This is validated due to the conversion of SW to LW.
That leaves us with a two body system, the surface as a source, and the atmosphere. Remember we are discussing radiation only. Other processes do exist like convection or conduction but those simply move energy away from radiation. At some point even that energy is radiated away or the earth would accumulate energy over whatever time frame you chose.
Energy does leave the system, i.e., into space.
“Assuming the atmosphere absorbs no SW radiation from the sun.”
Why would you assume this? Not even Kiehl and Trenberth 1997 assumes this.
“Energy does leave the system, i.e., into space.”
So it’s not an isolated system. At the least, you’re now talking about a closed system.
“Maybe Morlocks burning fossil fuels?”
I see–you’re not being serious. Or maybe, it’s just me you’re not being serious with.
I am being as serious as possible. Using averages when there is a T^4 term involved is the less than serious math. Not using gradients based on time, mass, specific heat, sines and cosines for radiation at each point on the earth are what is needed.
To use back of the envelope averages, one must simplify, simplify, simplify. Ideal bodies is just one. No other influences is another.
“Because averages hide things.”
This is why I keep posting the high resolution, near-real-time visualizations of NOAA’s “CO2 Longwave IR” Band 16 data from GOES East.
https://youtu.be/Yarzo13_TSE
In my opinion, the dynamic scene powerfully opposes the idea that we can determine how it works by computing and analyzing averages. The composite result emerges from a patchwork of widely differing and highly variable values of longwave emission. The “coldest” places in the images, the tops of the deep convective clouds in the warm tropics, and the “hottest” daily pulses, from the high altitude deserts are all part of the same scene. The system operates in constant dynamic response to absorbed and stored energy.
Exactly.
‘This is why I keep posting the high resolution, near-real-time visualizations of NOAA’s “CO2 Longwave IR” Band 16 data from GOES East.’
And thank you for doing so. I also agree with JG that ‘averages hide things’, but that’s not the same thing as believing that the inaptly named GHGs haven’t elevated the Earth’s average surface temperature.
I haven’t said the atmosphere/surface boundary doesn’t warm. Thermalizarion occurs and remains for a period of time at the boundary where thermometers are. Radiation disappears during that time. Water is evaporated causing cooling of the surface and removes radiation.
The sun/earth’s surface pair makes the earth appear to be a source. The surface will rise to an equilibrium temperature with the sun radiation and radiate at that temperature whether the atmosphere is there or not. Add a cool body, and nothing changes.
Here is how Planck addresses it.
“”””A body A at 100◦ C. emits toward a body B at 0◦ C. exactly the same amount of radiation as toward an equally large and similarly situated body Bi at 1000◦ C. The fact that the body A is cooled by B and heated by Bi is due entirely to the fact that B is a weaker, Bi a stronger emitter than A. We shall now introduce the further simplifying assumption that the physical and chemical condition of the emitting substance depends on but a single variable, namely, on its absolute temperature T .”””””
Cooling means net heat flows from hot to cold. Net heat goes to zero at equilibrium when radiation is equal both ways (if at all).
To warm the surface (hot body) one must refute the entropy law that heat moves from hot to cool.
I believe we came to an agreement on all this a while back, so I’ll restate my understanding of the so-called GHE – it’s basically the thermalization of the atmosphere due to the absorbing of thermal radiation by radiatively active GHGs.
This thermalization results in an atmosphere that would be very much warmer than an atmosphere without GHGs, except that it also gives rise to a convecting lower atmosphere, i.e., the troposphere, that moves thermalized air higher into the troposphere, where it can more efficiently cool by emitting radiation out into space.
The net result, then, is a nominally adiabatic troposphere that does not heat the surface, per se, but does delay the cooling of the surface relative to how quickly the surface would cool if it could radiate directly to space.
I agree with Happer et al that emitting more CO2 isn’t a big deal, but don’t want to dismiss the fact that the GHE is both a real and an essential feature of the Earth’s climate system.
Let me know if that works.
“the atmosphere only gets about two-thirds of its energy flux from absorbed upwelling surface longwave radiation. The other third of its energy flux comes from two totally different sources— 1) solar energy absorbed by the atmosphere”
This is part of the GH effect too though. GH gases affect incoming solar and outgoing terrestrial, storing their energy, smoothing out the daily high and low we would have (like a desert with its low WV), and creating a nice, warm average.
So the GH effect in total is, the energy at the surface, vs the energy escaping to space.
Thats the net warming of the GH effect
Greenhouse effect; carbon dioxide.
Commercial greenhouses maintain a CO2 atmospheric concentration of about 1 000ppm to 1 200ppm to aid plant growth.
So… why don’t commercial greenhouse catch fire, or at any rate boil their contents if the greenhouse effect is ‘real’ and carbon dioxide is the driver of atmospheric warming?
Because at the wavelength of a lot of the emitted photons at greenhouse emission temperature (around 300 K) are in the “atmospheric window”, 8-14 microns range, where they aren’t absorbed much by CO2 or water molecules in the atmosphere, and so will make it to outer space or be absorbed by Earth’s clouds.
“About 40 W/m2 of upwelling surface longwave goes directly to space.”
One wonders where this number comes from. If you’re quoting from Kiehl and Trenberth 1997, they don’t know where it comes from either.
In a reply to
Let’s take the two definitions to a logical conclusion. First assume there is no Greenhouse effect, G=0, Then with the Raval and Ramanathan definition we get F=E. This makes perfect sense. Without any ability to absorb IR input=output.
The other definition implies F=(I+L+S). LWIR at TOA is independent of LWIR input at the surface. Only energy input to the atmosphere by other means is included in F and this has to lead to several odd consequences irrespective of the atmospheric window.
Exactly. I was hoping someone would pick up on this on.
Why are some parts of the world ocean warming faster than average? For example the Red Sea, the Sea of Marmara, Lake Tanganyika, the Eastern Mediterranean?
Are the Great Lakes all warming together? Michigan?
JF
This is dividing IR radiation at the satellite with the IR radiation leaving the Earth’s surface.
The LWU IR radiation measured at the satellite is not 240W/m2. That is a theoretical estimate, not a measurement. The satellite actually measures 871W/m2.
But it gets worse. The 240W/m2 is roughly divided by 4. The IR leaving the surface is what is actually measured and is not divided by 4.
This is a comparison of apples and oranges.
Critical Analysis of Earth’s Energy Budgets and a new Earth Energy Budget
Brendan Godwin
6th April 2023
Earth and Space Science Open Archive
https://essopenarchive.org/users/539842/articles/645345-critical-analysis-of-earth-s-energy-budgets-and-a-new-earth-energy-budget
Your paper is interesting. Although I applaud your efforts, these diagrams are still flawed. You need diagrams that span the entire 24 hours of the day, and from pole to pole. Also the specific location of the Sun between the two Tropics needs to be added (not to mention the Earth’s location in its orbit). Of course, such would be a model. Then we are back to fantasy land until these scientists stop playing politics and start doing real science.
I still ask, “Where do KT97 get the 40 W/m^2 for the window?” The calculation in KT97 is nonsense. Using their numbers I get 87 W/m^2.
Jim,
KT97 get all their data from models, or what I call mathematical illusions. Their models are based on a whole lot of assumptions, most of which are false and none of which have been proven in any experiment.
Whilst the graph is generic in appearance, all the data for that graph has been obtained from the thousands of measuring stations all around the world covering 24 hours of the day and globally averaged.
No, Brendan, that graph is not produced from measurements. There are no downwelling Watts originating in the atmosphere. The thermal gradient doesn’t allow any such thing. That part is all made up – completely fictional. Here is a more accurate one (even though it is difficult to follow what’s going on when you average night-time and day-time conditions together, because energy flows are totally different in those two scenarios – like night and day, you might say):
Willis wrote: “the atmosphere radiates in two directions, up and down”
The atmosphere, like any object above absolute 0, certainly radiates energy both up and down. I hope you aren’t going to claim that the downward-radiated energy is measured in Watts. Are you?
Then he wrote: “atmospheric energy going upwards and downwards”
Ah, Willis tries to avoid the non-physical trap he nearly fell into above, by replacing Watts with the fisherman’s colloquial phrase “energy going downwards”. But I’m paying attention and I spotted the circumlocution.
No, Willis, atmospheric energy does not “go downwards”. The thermal gradient is all wrong for that to happen. Energy will only flow “down” the entropy slope, not up. (“down the entropy slope” is a physicist‘s colloquial phrase, and has nothing to do with gravity, which I’m sure will confuse you, but I’ll explain the precise definition next) That means, from lower-entropy states to higher-entropy states. In thermodynamics, that means from hotter to colder objects, or areas. And in our atmosphere, that means upwards. (Most of the time, with certain small and localized temporary exceptions, etc. etc.) And of course, that rule does not apply to solar shortwave energy heading from the sun to the surface through the atmosphere, which is also going “down” the entropy slope – as one would naturally expect.
“Please quote the exact words you are discussing. It avoids a host of misunderstandings.” Sadly, Willis, quoting your exact words back to you will not increase your understandings one iota. It certainly never has in the past. But I’ll do it anyway, because you asked nicely, and that’s just the kind of fellow I am.
My request to you is different, but it matches what you told me earlier: remember your debating hierarchy pyramid! That means there is no point in replying to my physics statement with a slew of your usual logical fallacies, such as Argument from Authority, Argument from Incredulity (“Pass!”), Argument from Ignorance, Argument from “Common Sense” a.k.a. the Willis Eschenbach Fallacy, Argument Ad Hominem (“Pond scum!”), etc. Remember that you are trying to pass yourself off as a scholar and a gentleman, and those folks never resort to logical fallacies and name-calling. Only fishermen and cowboys who are way out of their intellectual depth would do that. Right?
Dang, steve, do you think you could possibly pack more insults and personal attacks into a few paragraphs, one of which decries personal attacks as only coming from someone “out of their intellectual depth”? … talk about getting hoist by your own petard!
In any case, regarding your actual points. You say:
I fear you are conflating radiant energy flow and heat flow. Heat, as you point out, is the spontaneous flow of NET energy from warm to cold.
But radiant energy (measured in watts or W/m2) flows in any direction. A photon leaves an object, and whatever it strikes becomes slightly warmer. If you light a candle during the day, the sun gets warmer from the photons from the candle … not much warmer, to be sure, but warmer nonetheless.
Yes, the NET flow of energy, aka “heat”, is always and invariably from the sun to the candle, because the sun is hotter. But there is a flow of energy in both directions. See my post “Can a cold object warm a hot object” for a discussion of the question of radiant energy flows.
And let me suggest that you dial back on the aggro. You think it makes you look smart and witty. In fact, it just makes people point and laugh, and they’re not laughing with you.
Here’s a thought experiment for you. Imagine a hot star “H” in space. It has a steady-state temperature. Next, imagine a cool star “C” in space. It also has a steady-state temperature, which is lower than that of the hot star.
Now, imagine we put them right next to each other. What happens to the temperatures?
1) Both get colder.
2) H gets colder, C gets warmer
3) C gets colder, H gets warmer.
4) Both get warmer.
I say the answer is 4), both get warmer, because each one is warmed by the radiant energy emitted by the other one. Yes, there is a NET heat flow from H to C, required by thermodynamics. But both stars will still get warmer by being placed next to each other.
Regards,
w.
Willis,
Far be it from me to correct you, but I think you need to revise your example.
S/B has (σ₁T₁⁴ – σ₂T₂⁴)
If T₁ and T₂ increase, where does it stop? T₁ is warmed by T₂ and then radiates more to T₂, and around we go.
One needs to wrap their head around the fact that NET radiation is toward T₂ which is warmed while T₁ is not.
From Planck:
“”””A body A at 100◦ C. emits toward a body B at 0◦ C. exactly the same amount of radiation as toward an equally large and similarly situated body Bi at 1000◦ C. The fact that the body A is cooled by B and heated by Bi is due entirely to the fact that B is a weaker, Bi a stronger emitter than A.””””
“”””When any emitting and absorbing bodies are in the state of thermodynamic equilibrium, the part of the energy of definite color emitted by a body A, which is absorbed by another body B, is equal to the part of the energy of the same color emitted by B which is absorbed by A. Since a quantity of energy emitted causes a decrease of the heat of the body, and a quantity of energy absorbed an increase of the heat of the body, it is evident that, when thermodynamic equilibrium exists, any two bodies or elements of bodies selected at random exchange by radiation equal amounts of heat with each other.””””
Willis wrote: “But radiant energy (measured in watts or W/m2)”
No, Willis, this is why I say that you are out of your intellectual depth. (Well, one of the reasons, another being that it is completely impossible to teach you anything.) Energy is not measured in Watts. Have you ever cracked open a physics textbook? Even once? What do you think is the difference between “energy” and “power”?
For your two-star example, the rate of energy loss (or gain) from an object to its surroundings depends on the temperature of both the object and the surroundings. So an object will cool (lose energy) more slowly if its surroundings heat up (e.g. if cold space is replaced by a nearby hot star.) So you are right, two adjacent stars will both be hotter than if they were isolated from each other and surrounded by cold space. The same is true if the cold surroundings are replaced by a mirror.
But that does not change the fact that radiation is energy, as you said, but not power, and converting energy into power requires an entropy gradient. You have consistently failed to grasp this, and your whole “steel greenhouse” is an intellectual tour-de-farce as a result.
Radiation is energy. Energy is measured in Joules, or degrees. Not Watts.
I do have to give you credit for not resorting to any logical fallacies in this response, this time, though. Good job! You stuck to the actual physics, even though your claim was false.