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Eclectic at 19:54 PM on 26 November 2024CO2 effect is saturated
CallItAsItIs @751 & prior :-
Yes indeed, it is "ultimately the sun that drives warming of the entire earth, both the solid part and the atmosphere".
And for practical purposes, we can ignore the (fission) heat generated subterraneously, and heat generated by tidal motion, and heat generated by combustion of fossil fuels etcetera.
But when discussing atmospheric physics, it would be substantially wrong to ignore the direct heating of the atmosphere by sunlight (as short-wave radiation, including UV radiation). There is a famous "cartoon" by Dr Trenberth, giving a summary of the various energy flows in the terrestrial atmosphere ~ quite colorful, though the exact figures utilized are perhaps only accurate to about +/- 1%.
Forgive me, but I feel you are pulling my leg, when you say (with your atmospheric interest) that you have not heard of Trenberth. Just like I would feel when a Rocket Scientist says he has not heard of Newton.
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CallItAsItIs at 19:24 PM on 26 November 2024CO2 effect is saturated
Eclectic @750
Well, it is ultimately the sun that drives warming of the entire earth, both the solid part and the atmosphere. The primary mechanism for the sun warming the earth is the absorption of visible light (from the sun) into the solid portion of the earth which then acts as a near blackbody. This blackbody radiator then warms the atmosphere by conduction and convection.
It should be noted that convection is important for the CO2 greenhouse effect to work since the 15 micron absorption band of CO2 is strong enough to pack the thermal radiation from the entire band into a layer at the surface just a few tens of meters thick. Without convection, this would give us a very hot surface. Also, however, there would be a steep temperature gradient near the surface which would result in a strong pressure gradient. This pressure gradient would then drive updrafts that would carry excess heat away from the surface. In this manner, convection stops excessive heating of the bottom layer of the atmosphere.
Finally, I am not familiar with Trenberth's summary. Could you give me a link or a reference?
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Eclectic at 18:08 PM on 26 November 2024CO2 effect is saturated
CallItAsItIs @749 :-
Please do not forget about the Sun warming the atmosphere.
Also, convection and H2O phase changes, etc.
I'm fairly sure you were going to mention all these other factors, and also bring Trenberth's summary into the discussion. After all, we would be remiss if we ignored the Big Picture and focused entirely on only IR photons and the abstract "Laws of Physics".
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CallItAsItIs at 16:16 PM on 26 November 2024CO2 effect is saturated
Bob Loblaw @ 744
From this comment and several others of yours, I believe we need to get some basics straight so that you and I are consistent in our use of various term (eg. thermal radiation). Also, we need to be certain we are even working the same problem. Although I am addressing this message specifically to you, Charlie_Brown, Eclectic, and scaddenp are certainly welcome to tune in.
In this problem, we are trying to assess warming of the atmosphere due to IR radiation eminating from the surface of the earth. This earth-emitting IR is estimated as a blackbody at about 288 deg. K, although we do consider it to be adjustable.
For energy conservation, we must take this to be the only source of energy causing addtional warming to the entire atmosphere. This does not mean, however, that energy can't change forms within the atmosphere. Indeed, this is what happens in establishing thermal equilibrium. But there cannot be any change in total energy in the process. The atmosphere does not consume fuel and has no means of generating new energy.
Next, we assume that the molecules and photons are of sufficient number that it makes sense to talk about smoothly varying densities, fluid velocities, temperatures, and pressures. Also, we assume that thermal equilibrium is maintained at least locally. This is what enables us to discuss different temperatures at different altitudes.
The term thermal radiation is used to denote the distribution of EMR when thermal equilbrium is reached. If the atmosphere was totally absorptive at all EMR frequencies, then the thermal radiation would simply be given by the Planck distribution. Of course this is not the case for the entire EMR spectrum, but at wavelengths near 15 microns or other bands that are strongly absorptive, the atmospheric radiance at those wavelengths comes close to matching those of a blackbody at the temperature where the measurement is taken.
Applying this concept of thermal radiation to the TOA (about 70km altitude), we find that CO2 in effect forms a narrow bandwidth "blackbody" at the 15 micron wavelength. At this point, the detectors pick up on the emissions from this "blackbody" since there is no more CO2 at the TOA to attenuate them. This is why the last three curves that Bob Loblaw posted in 731 all show the same intensity (about 6 W/m^2) and the same temperature (about 220 deg. K) of the 15 micron band. Emissions from this band at lower altitudes and higher temperatures have all been absorbed.
At this point, we still need to discuss absorption coefficients and the Beer Lambert equation which govern the conversion of upwelling IR radiation from the surface to thermal energy of the atmosphere, but I think I will wait for feedback before I spend any more time at this.
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CallItAsItIs at 13:27 PM on 26 November 2024CO2 effect is saturated
Charlie_Brown @745
Could you please explain to me how my postings are not consistent with Kirchhoff's Law?
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Bob Loblaw at 03:54 AM on 26 November 2024CO2 effect is saturated
Regarding Charlie Brown's comment at 745 (and earlier) about thinking of Beer's Law from the perspective of the top of the atmosphere:
- Beer's Law is a probability relationship. It tells us the likelihood that a certain number of photons will be absorbed over a given distance (which is better described as a given number of absorbing molecules - it's the mass of absorbing molecules that matters).
- An individual photon maybe absorbed at the start of that path, in the middle, or at the end - or not at all.
- Beer's Law just says "on average, this portion will be absorbed".
- As we move away from the source, the probability that a photon will get that far decreases.
- When looking at what comes out of the top of atmosphere, Beer's Law tells us the probability that a particular photon came from a source at distance X (again, "distance" = number of molecules).
- There is a higher probability that it came from a close source than a distant source.
As we follow the 15um flux up from the surface, Beer's Law tells us that at each height, we're probably looking at more photons that were emitted at heights slightly below where we are, and fewer photons that were emitted far, far below where we are. There will always be 15um photons flowing upward, though.
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Bob Loblaw at 03:39 AM on 26 November 2024CO2 effect is saturated
I feel as if I'm on the verge of beating a dead horse - no idea if CallItAsItIs will respond to the latest comments, but....
I think it is useful to provide a graphic published in a 1967 paper by Manabe and Wetherald.
Figure 16 looks like this:
Note that increasing CO2 increases surface temperatures, but leads to cooling in the stratosphere. Why? Many factors, but one of them is that by adding CO2, the overall emissivity of the atmosphere increased - so the atmosphere can emit the same IR radiation to space at a lower temperature. Kirchoff's Law at work - both absorptivity and emissivity change in unison.
But CallItAsItIs has not yet caught up with science from 1967, so he believes that only the emission of "thermal radiation" is being picked up by satellite sensors, and there is no emission from CO2.
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Charlie_Brown at 03:13 AM on 26 November 2024CO2 effect is saturated
Bob’s points are spot on. CallItAsItIs sometimes uses Kirchhoff’s Law and sometimes forgets about it. There is one more interesting point that I would like to add about interpreting the graphs. They demonstrate conclusively that there are sufficient CO2 molecules to form an emitting layer (emittance = 1.0) at the bottom of the stratosphere. This shows the value of interpreting Beer’s Law by looking down from the top of the atmosphere.
CallItAsItIs misses the interpretation when he says “the intensity at 15 microns approaches a value corresponding to a 220 K blackbody. This, in turn, corresponds to an altitude of about 70 km, above which there isn't much of an atmosphere.” 220 K also corresponds to an altitude of 24 km and that is the source of radiant energy loss to space in the 14-16 micron band. How do I know? Look at the 15-micron peak, which is composed of a few very strong emittance lines, in the spectrum at 50 km. The temperature at that altitude is 270 K, but the top of the peak corresponds to the Planck distribution of 241 K. By Beer's Law, there are not enough CO2 molecules to bring the emittance to 1.0 for the strongest peak.
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Bob Loblaw at 03:02 AM on 26 November 2024Fact brief - Does manmade CO2 have any detectable fingerprint?
Rkcannon:
The paper in question, by Skrable et al, was discussed shortly after it appeared, over at AndThenTheresPhysics.
Note that the ATTP blog mentions a total of five rebuttal comments that were submitted to the journal.
Executive summary: the paper is a piece of junk.
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Eclectic at 02:33 AM on 26 November 2024Fact brief - Does manmade CO2 have any detectable fingerprint?
Rkcannon @1 :-
you mention a 2022 paper published in "Health Physics" by authors Skrable, Chabot, et al.
I gather that the journal "Health Physics" is primarily concerned with the topic of radioactivity effects on human health.
Presumably the Skrable paper had been rejected by reputable journals that normally published general scientific matters (including the physics of climate science).
Judging by Skrable's Abstract, the authors have made a colossal fundamental error in their understanding of the carbon cycle (involving the movement of CO2 into and out of Earth's atmosphere). And hence their conclusion is grossly erroneous.
The puzzle is : how did the journal Editor fail to see this error.
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rkcannon at 01:29 AM on 26 November 2024Fact brief - Does manmade CO2 have any detectable fingerprint?
Please comment on the following paper "World Atmospheric CO2, Its 14C Specific Activity, Non-fossil Component, Anthropogenic Fossil Component, and Emissions (1750–2018)" concluding "We determined that in 2018, atmospheric anthropogenic fossil CO2 represented 23% of the total emissions since 1750 with the remaining 77% in the exchange reservoirs. Our results show that the percentage of the total CO2 due to the use of fossil fuels from 1750 to 2018 increased from 0% in 1750 to 12% in 2018, much too low to be the cause of global warming." Fact or fiction?
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Bob Loblaw at 00:55 AM on 26 November 2024CO2 effect is saturated
To try to make a few points, independent of CallItAsItIs's confusion:
- All objects with a temperature >0 Kelvin emit radiation. (Planck's Law)
- As temperature increases, this shifts to shorter wavelengths (higher frequency).
- When an object primarily emits in the IR range, this is often called "thermal radiation", but radiation consists of photons, regardless of wavelength.
- At a specific wavelength (e.g. 15um), all photons are the same. They have no memory of what emitted them, and no memory of what temperature that object was at.
- There are no "thermal radiation" 15um photons that act differently.
- There are no "288K" 15um photons that act differently.
- There are no "surface-emitted" 15um photons that act differently.
- There are no "CO2 can't absorb this" 15um photons that act differently.
- There are no "CO2 will absorb this" 15um photons that act differently.
- They are just "15um photons".
- Gases are highly selective with respect to what wavelength of photons they will emit. This has to do with energy levels in the gas molecule: the structure only allows for certain energy levels, and as the molecule drops from one level to another, a photon is emitted with that energy - and photon energy is directly related to its wavelength.
- Gases will absorb photons at the same wavelengths they emit. (Kirchoff'sLaw)
- This does not mean that energy obtained from absorbing a 15um photon has to be emitted as a 15um photon.
- Energy lost by emitting a photon has to match the energy in that photon, but the energy can come from anywhere. Absorption of radiation at other wavelengths, obtaining energy via collision with other molecules (the dominant factor in the atmosphere), chemical reactions, etc.
To call it as it is, it appears that CallItAsItIs fails to understand many of these essential aspects of physics and radiation transfer.
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Bob Loblaw at 00:25 AM on 26 November 2024CO2 effect is saturated
CallItAsItIs @ 740:
Are you actually paying attention to what you are saying?
- You have been claiming that there is no 15um IR radiation above your "extinction height" (10m) for CO2 to absorb.
- I showed graphs (albeit modelled) with non-zero 15um radiation at altitudes from 10km to 70 km.
- Now, you claim that the presence of that 15um IR radiation from 10km through 70km "tend[s] to show that I [you] am right", because "the detectors are only picking up some thermal radiation from the TOA".
The level of physics denial is astounding. For your explanation to be correct, the entire atmosphere between the lower near-surface layers and the top of atmosphere layers cannot emit IR radiation in the 15um band. In your version of "physics":
- There is lots of 15um IR radiation emitted upwards at the surface...
- ...but a short distance above the surface, suddenly there is no upward emission of 15um radiation...
- ...and there continues to be no upward emission of 15um radiation as we move higher and higher in the atmosphere....
- ...until suddenly, at the top of the atmosphere, we suddenly find conditions that allow for the emission of 15um radiation so that the satellite sensors can pick it up.
- ...and somehow "thermal radiation" is some different entity that does not exist in all those layers between the surface and the TOA. It only appears at the TOA, where you need it to "explain" what is measured from space.
You are creating a physics-free zone between the surface and the TOA. In spite of the fact that the entire atmosphere has a temperature above 0K, and therefore contains thermal energy, and therefore emits thermal radiation (including 15um radiation, because the CO2 that is present can do that...), you have declared that none of that physics applies and none of the upwelling 15um radiation that is measured between the surface and the TOA exists.
...and then in comment 741, you wander off into a tangent claiming that my explanation in comment 732 requires that the atmosphere "heats itself" and "violate[s] energy conservation". That is more physics denial. Any object with a temperature >0K contains thermal energy. And the laws of physics state that any object >0K will emit radiation.
When a molecule emits radiation, it loses energy (conservation of energy maintained) and will cool, but each molecule is capable of regaining energy by collisions with other molecules, or by absorbing radiation (in any wavelength - the absorption and emission do not need to be in the same wavelength).
Remember in comment 722 when you said?:
In the case of CO2 and the 15 micron absorption band, the N2 and O2 molecules in the surrounding air collide with energized CO2 molecules which causes the extra energy (from absorbed photons) to be converted into thermal energy, thereby raising the air temperature.
The opposite is also true. CO2 can gain energy from N2 and O2 through collisions, when the N2 and O2 molecules are at higher thermal energy levels than the CO2. That is what predominantly drives the "thermal radiation" emitted by CO2 at all levels in the atmosphere. You can read the technical details in this post at Eli Rabett's blog.
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Eclectic at 17:36 PM on 25 November 2024CO2 effect is saturated
Charlie_Brown @739 :-
Our two-way conversation is getting rather off-topic for this thread.
I am sure that we two are "on the same side" regarding AGW/science. But there is clearly a large semantic discrepancy with our individual understandings of the meaning of certain English words ~ and it would take far too long for us to negotiate a mutual agreement on the semantics.
Let it slide.
The point which I found interesting (and which I always find interesting in reading all the nonsenses, bad science, and Motivated Reasonings to be found on the WUWT website) . . . is that our new friend [viewed @722 ; @723 ; @726 ; @730 ; @740 ; and @741 ] and suchlike people ~ are coming to pseudo-science conclusions because of poor logic and poor understanding of the physical universe of particles & photons. They are hampered by their confusions of realities vs abstractions (e.g. the mental constructions achieved by the great scientists of the 18th, 19th, and later centuries. Constructions which have been dignified by the label "Laws" ) .
[ Off-hand, I do not know of a suitable thread on SkS , for the discussion of the philosophy of science as expressed through human psychology & semantics. ]
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CallItAsItIs at 15:11 PM on 25 November 2024CO2 effect is saturated
Bob Loblaw @732
Regarding your comment
Please buy a clue, CallItAsItIs. We do not need to "bring an IR source up there" - there already is one. It's called "the upper atmosphere", it contains CO2, and it is warmer than 0K. Climate scientists actually know about this obscure "upper atmosphere" as a source of IR radiation, they know how to calculate its effect, and they know it plays a role in atmospheric greenhouse warming.
Are you saying that the atmosphere heats itself!? Wrong! This would violate energy conservation. In order to to heat the atmosphere, we must bring in IR from outside the atmosphere. In the case of greenhouse warming, this is the 288 K IR eminating from the surface of the earth.
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CallItAsItIs at 14:44 PM on 25 November 2024CO2 effect is saturated
Bob Loblaw @ 731
I hate to disappoint you, but your curves tend to show that I am right. As the observation altitude increases, the intensity at 15 microns approaches a value corresponding to a 220 K blackbody. This, in turn, corresponds to an altitude of about 70 km, above which there isn't much of an atmosphere. Therefore, for the 15 micron band, the detectors are only picking up some thermal radiation from the TOA. Any upwelling radiation from this band has already been completely absorbed at lower altitudes.
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Charlie_Brown at 13:54 PM on 25 November 2024CO2 effect is saturated
Eclectic @737,
I strongly disagree with your description of the laws of science. The definition is not like legalistic law. Understanding and applying them properly is in no way lazy. They are not concepts. In the scientific use of the word, they are physical reality. The laws of gravity, conservation of energy, the 2nd law of thermodynamics, and radiant energy transfer have never been found to have been violated. But it does take knowldege and careful thought to apply them correctly. It is like the old cliché about statistics never lie but liars use statistics. Statistics are rigorous but too many people use them improperly.
Yes, I know the thread about the 2nd law of thermo about a colder thing cannot warm a warmer thing. I answered the issue with Gerlich & Tscheusner’s paper @1535 by pointing out that G&T made a mistaken assumption that the mechanism of global warming was “radiatively equilibrated.” Since global warming results from an upset to steady state equilibrium, there is no violation of the 2nd law. Understanding the law and G&T mistaken assumption should have put a stop to that myth.
In this case, Beer’s Law (I use that term now as Beer focused on concentration while Lambert focused on column length, but both convey the same concept, the atmosphere essentially has a fixed column length) is only one part of the mechanism of global warming. As I tried to say very clearly to CallItAsItIs, he errored by not applying Kirchhoff’s Law. Anyone who doesn’t understand it should study it before making comments before spreading misinformation. Errors made by science denialists need to be found and explained. I think that using the laws of science is the best way to be convincing. The challenge is to find the errors and explain them in understandable terms.
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Bob Loblaw at 12:08 PM on 25 November 2024CO2 effect is saturated
Electic:
The issue with Beer's Law is not that it is incorrect - it's that it is incomplete. It only deals with the absorption side of the radiative transfer process. It says nothing at all about the emission side. To properly describe and understand the greenhouse effect and IR radiative fluxes (upwards and downwards), you need both. Beer's Law only gets you half way there.
It's kind of like trying to balance your bank book by adding up all the deposits and ignoring the withdrawals (or vice versa).
There is useful discussion of Beer's Law on this "From the email bag" post (now almost three years old). In particular, read the first few comments where Charlie Brown and I start to discuss the "extras" needed to complete the picture.
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Eclectic at 11:27 AM on 25 November 2024CO2 effect is saturated
@735 :-
Thank you, Charlie_Brown, but please look to the main thrust of my comment.
Which is that: regardless of Beer's Law, Bouguer's Law, Lambert's Law, Kirchhoff's Law, Thermodynamics Law(s), etcetera . . . we must not get in the rather lazy habit of accepting famous "Laws" in an automatic way ~ by taking the legalistic approach that holds that words & concepts are equivalent to actual physical reality (rather than as sometimes convenient guides).
I'm sure you have seen that sort of thinking quite often with Climate Science Deniers who assert that "a colder thing cannot warm a warmer thing" (and so on).
Sometimes the old "Laws" are fine in most circumstances; sometimes they are useful as approximations ~ but "Laws" are essentially concepts rather than hard realities of particles/photons. And they can ~ sometimes ~ mislead our thinking. Beware of Laws.
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scaddenp at 10:34 AM on 25 November 2024CO2 effect is saturated
CallItAsItIs - posters above are trying to educate you about how to work with atmospheric physics but so far you appear to be very reluctant to understand the points made.
Can we agree as a starting point that nature has the final say? Ie the basis of science. You are proposing a, let's say, novel hypothesis for physics where as climate science is using the long established model of radiative transfer. That model allows us to predict what instruments on ground, balloon, satellite will measure for spectrum (and many other things as well). Your hypothesis would give very different observations.
Are you prepared to let the observations decide the argument? -
Charlie_Brown at 10:08 AM on 25 November 2024CO2 effect is saturated
Eclectic @ 734
The fundamental laws of radiant energy, including Beer’s Law, are entirely germane to the mechanism of global warming. They are not mental shortcuts. Einstein was in another league when thinking about the theory of relativity.The problem for CallitAsItIs is that he does not apply Beer’s Law correctly as it applies to radiant energy leaving the top of the atmosphere. He views, incorrectly, attenuation of the original source radiation from the surface, calling it “extinction.” This is the same mistake that Angström made in 1900 and too many others have followed since because it overlooks Kirchhoff’s Law. Bob Loblaw gets it right because he uses the MILIA (MODTRAN Infrared Light in the Atmosphere) model looking down from the top of the atmosphere at 70 km. Beer’s Law is very important because it defines the molecular density in the atmosphere that raises the emittance of a specific wavelength to a value of 1.0. Note that the minimum atmospheric temperature for the Tropical Atmosphere is 195 Kelvin at 17 km. The reason the bottom of the CO2 trough begins to rise at higher altitudes is the increasing temperature of the ozone layer. This demonstrates clearly that there are sufficient CO2 molecules, by Beer’s Law, to form an emitting layer at that altitude.
It is enlightening to run the model at 10 meters looking down. The spectra follows the Planck distribution because all source photons from the surface that are absorbed by CO2 are re-emitted. Kirchhoff's Law.
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Eclectic at 07:33 AM on 25 November 2024CO2 effect is saturated
CallItAsItIs :-
Your explanation falls short of reality.
At the planetary scale, the "Beer-Lambert Law" is not germane to the situation (see Bob Loblaw's further comments, above).
Always beware of "Laws" composed centuries ago. The so-called Laws were useful as mental short-cuts, in some but not all circumstances.
As Einstein would say: Take your nose out of the lawyers' books, and look at the real universe.
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Bob Loblaw at 07:14 AM on 25 November 2024CO2 effect is saturated
I noticed that CallItAsItIs, in comment 730, has stated that his "extinction height" is a mere 10m. If this actually prevented there from being any upwelling 15um radiation above that height, then all the graphs I supplied in comment 731 should show zero for intensity at 15um.
The astute observer will note that the graphs do no such thing.
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Bob Loblaw at 07:02 AM on 25 November 2024CO2 effect is saturated
CallItAsItIs @ 730 once again completely ignores the known and measured fact that upwelling IR radiation at 15um, as measured at high altitudes, does not need to come from the surface.
He even has the answer in his comment (emphasis added):
Regarding the CO2 molecule at 50000m, it most certainly can absorb the 15 micron IR photons — if you bring an IR source up there.
Please buy a clue, CallItAsItIs. We do not need to "bring an IR source up there" - there already is one. It's called "the upper atmosphere", it contains CO2, and it is warmer than 0K. Climate scientists actually know about this obscure "upper atmosphere" as a source of IR radiation, they know how to calculate its effect, and they know it plays a role in atmospheric greenhouse warming.
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Bob Loblaw at 06:54 AM on 25 November 2024CO2 effect is saturated
To show how CallItAsItIs is wrong, let's look at the upward-directed IR radiation calculated using the MODTRAN model I mentioned in comment 725. We'll stick to the default tropical atmosphere with no clouds - changing only the altitude we're looking down from.
Let's start at 10km altitude.
Lots of radiation at 15um there. Haven't reached "extinction" yet. Lets' go higher, to 20km...
A substantial reduction in 15um intensity. Are we close to CallItAsItIs's "extinction" height yet? Let's go higher, to 30km...
Oh, no! IR intensity at 15um has increased! How on earth is that possible? Where are those 15um photons coming from? If they were blocked from reaching 20km (from the surface), then how can they possibly be appearing at 30km altitude? At 30km, we're now in the stratosphere and the atmosphere is getting warmer again. Could it be possible that this warmer atmosphere is actually emitting 15um photons?
Maybe we need to go higher. Try 50 km.
Oh, crap. 15um intensity is even higher. Let's try 70km.
That's almost the same as at 50km.
So, where is this "extinction" point where CallItAsItIs claims there will be no more 15um IR radiation for CO2 to absorb? That "extinction" point only exists in CallItAsItIs's imagination.
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CallItAsItIs at 06:54 AM on 25 November 2024CO2 effect is saturated
Eclectic @728
The extinction altitude of an absorption band of a GHG is the altitude at which the upwelling radiation with the band becomes negligible according to the Beer-Lambert law and the absorption coefficient of the band. For CO2, the absorption band is 14-16 microns and the extinction altitude is about 10 meters. This means the upwelling IR radiation absorbed by CO2 at the top of the credible atmosphere is pretty miniscule. Above that, of course, it is zero.
Regarding the CO2 molecule at 50000m, it most certainly can absorb the 15 micron IR photons — if you bring an IR source up there. The reason there is no absorption at that altitude is because all 15 micron IR has already been absorbed at lower altitudes.
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Charlie_Brown at 06:44 AM on 25 November 2024CO2 effect is saturated
First, thanks to Bob for the call out. Studying the post and the linked article in Chemical Engineering Progess should be an effective means of education.
CallitAsitis @726:
You have a misunderstanding of Kirchhoff’s Law: Absorptance = Emittance (at thermal equilibrium, i.e., temperature not changing) A CO2 molecule absorbs a photon related to a specific wavelength, increasing its internal energy level. It collides with adjacent N2 and O2 molecules and transfers energy so that the molecules are in thermal equilibrium. Since CO2 still vibrates, it also emits photons at specific wavelengths. For the molecule, the net result is essentially a pass-through. For a column of atmosphere, it is not conservation of photons but conservation of energy.You also have a misunderstanding of the absorptance/emittance lines for CO2 and water vapor. See Figure 3 in the post linked by Bob. The Stefan-Boltzmann Law is applied to each line:
Intensity = emittance x Stefan-Boltzmann constant x absolute temperature to the 4th power.Your understanding of absorptance/emittance as a function of altitude is not correct. Energy loss to space is best conceptualized by looking down from the top of the atmosphere, not by looking up from the surface. Looking down, Beer’s Law determines the altitude at which there are sufficient molecules in the optical path to bring the emittance to 1.0. For strong CO2 emittance lines, it is the cold, thin atmosphere at the bottom of the stratosphere. For weak emittance lines, it is at a lower, thicker, warmer altitude, with a minimum altitude being the Earth’s surface which emits as a blackbody. As CO2 increases, the molecular density in the cold upper atmosphere increases, the weak emittance lines strengthen, and intensity of emitted energy decreases because of the lower temperature.
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Eclectic at 06:20 AM on 25 November 2024CO2 effect is saturated
CallItAsItIs @726 (and prior) :-
You are expressing yourself in an unclear manner ~ almost bizarrely.
e.g. What is the term "extinction altitude" that you use?
And why do you say that a CO2 molecule "can no longer absorb" (at the 15 micron wavelength) when the molecule is at say 50,000m altitude versus when the molecule is at say 50m or 500m altitude? Please explain.
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Bob Loblaw at 06:11 AM on 25 November 2024CO2 effect is saturated
CallItAsItIs @ 726:
Frankly. you don't know what you are talking about.
- If IR radiation is present in a band that CO2 absorbs at, CO2 can absorb it.
- If CO2 is present at a temperature above 0K, it will emit IR, and do it in exactly the same bands that it absorbs at.
- Since the entire atmosphere, at any altitude, contains both CO2 and is at temperatures above 0K, there will be CO2 that is both absorbing and emitting IR radiation in the 15um band.
I know this seems like a difficult concept for you to grasp, but the atmosphere has more than just a top and a bottom. In fact, almost all of the "credible atmosphere" exists in the zone between the top and the bottom, and until you learn that you will continue to spout garbage.
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CallItAsItIs at 04:56 AM on 25 November 2024CO2 effect is saturated
Bob Loblaw@724
Above the extinction altitude of the 15 micron band, CO2 can still emit IR radiation (at any wavelength) but can no longer absorb within this band. The fact that CO2 can no longer absorb within this band means that it has zero greenhouse forcing at this altitude and above for the simple reason that there is no more 15 micron radiation that can be absorbed. The small amount of 15 micron energy that reaches orbital sensors comes from blackbody emissions from the top of the credible atmosphere. This radiation cannot, however, be absorbed since there is no more atmosphere.
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Bob Loblaw at 03:06 AM on 25 November 2024CO2 effect is saturated
As an FYI, the IR flux vs altitude question (both upwelling and downwelling) can be explored using the online MODTRAN model. To start, I suggest reading this blog post guest-authored by frequent reader/commenter Charlie Brown.
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Bob Loblaw at 00:14 AM on 25 November 2024CO2 effect is saturated
CallItAsitis @ 722 and 723:
Unfortunately, your understanding is incomplete and makes a common error by many that have tried to argue that the CO2 effect is saturated.
Your error is most easily seen in your statement "Above this altitude, there is no more upward-bound IR energy that CO2 molecules can absorb." This simply is incorrect, because your statements completely ignore the fact that CO2 also emits IR radiation. As long as CO2 is emitting IR radiation (at 15um and any other wavelength where CO2 is active), there will continue to be an upward-directed flux of IR radiation at those wavelengths. Since CO2 is present throughout the atmosphere, you will never, ever, see an altitude at which there is no upward flux of 15um radiation.
As long as you ignore the emission of IR radiation by CO2, you will fail to understand the greenhouse effect, and fool yourself with respect to "saturation". Your definition of "saturation" looks only at surface-emitted IR radiation and whether it can pass through the entire atmosphere in one go. It is your view of "saturation" that makes no sense.
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CallItAsItIs at 21:00 PM on 24 November 2024CO2 effect is saturated
I have a question about the video posted in the Intermediate rebuttal. At about 2:38 into this video, Mr. Richardson states "in the upper layers of the atmosphere, the greenhouse effect isn't saturated". I need clarification on this since band saturation is not an altitude dependent quantity. As I understand it, the greenhouse effect is saturated for a particular GHG if there is an altitude at which the absorption bands for that GHG have all been depleted (from the upwelling IR radiation) through absorption at lower altitudes. Therefore, a GHG is saturated for a particular atmospheric profile of the GHG, or it isn't. It's not saturated at one altitude but not another. Such statements don't make sense.
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CallItAsItIs at 20:18 PM on 24 November 2024CO2 effect is saturated
I would like to make a few comments concerning the following paragraph in the Further details section.
Greenhouse gases in the atmosphere, such as CO2 molecules, absorb some of this IR radiation, then re-emit it in all directions - including back to Earth's surface. The CO2 molecule does not fill up with IR photons, running out of space for any more. Instead, the CO2 molecule absorbs the energy from the IR photon and the photon ceases to be. The CO2 molecule now contains more energy, but that is transient since the molecule emits its own IR photons. Not only that: it's constantly colliding with other molecules such as N2 and O2 in the surrounding air. In those collisions, that excess energy is shared with them. This energy-sharing causes the nearby air to heat up (fig. 2).
This is correct but it should also be noted that the absorption spectrum of CO2 is quite different than that for H20 vapor. In the case of CO2, strong absorption occurs but primarily in the (narrow) 15 micron band. Absorption or emission of IR by CO2 outside this band is generally considered to be small. For H20, however, we find weaker absorption but it is much more evenly spread out over the entire IR spectrum. Therefore, the CO2 greenhouse effect is determined primarily by what happens in the 15 micron band.
In the case of CO2 and the 15 micron absorption band, the N2 and O2 molecules in the surrounding air collide with energized CO2 molecules which causes the extra energy (from absorbed photons) to be converted into thermal energy, thereby raising the air temperature. Once this warming occurs, however, the upwelling 15 micron IR energy is reduced by the amount of thermal energy that was released in the collisions involving CO2 molecules. Otherwise, energy would not be conserved. Band saturation occurs if the upwelling 15 micron radiation is reduced to negligible values at some altitude below the TOA. Above this altitude, there is no more upward-bound IR energy that CO2 molecules can absorb. Essentially, the entire 15 micron band has been absorbed and additional CO2 would not cause further greenhouse warming.
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Billy at 10:33 AM on 24 November 2024A look back - SkS in 2014
so glad i found this site. It's fun digging.
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Stephan B. at 12:17 PM on 23 November 2024The Skeptical Science temperature trend calculator
Kevin Cowtan's trend calculator is a very useful tool!
But all available datasets end in March 2023, which is a bit outdated. Could you please update the datasets and maintain them on a regular base (like 6 months or at least annually)?Kind regards
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One Planet Only Forever at 07:52 AM on 23 November 20242024 SkS Weekly Climate Change & Global Warming News Roundup #46
nigelj @10,
I am not too concerned about the order of the listing. My thinking was to:
- Start with 'what people should be interested in learning about' through the reporting of harms done.
- Next is learning about what could be done to reduce the harms.
- Then comes news reports specifically on new published science/research. Note that these news items will probably also be tagged for a second category.
- News exposing and correcting dis- and mis-information
- News about leadership actions can then be understood in the context of all the above.
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BaerbelW at 05:24 AM on 23 November 20242024 SkS Weekly Climate Change & Global Warming News Roundup #46
OPOF @ 8&9
Thanks much for these suggestions! I had asked Google's NotebookLM to identify topics based on several but fairly random editions of our weekly news roundup and the listing - while a lot more fine-grained - is not that much different from what you came up with. What we plan to do - as soon as we get around to finalizing the list - is to add a drop-down selection field to the Google form we already use to collect articles suitable for sharing on our social media channels. We can then in turn use that information when we generate the round-up blog post.
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nigelj at 04:56 AM on 23 November 20242024 SkS Weekly Climate Change & Global Warming News Roundup #46
OPOF @9, your categories look good to me. Seven primary categories is also a good number. Any more and it would overcomplicate things.
I would have put climate science and research first on the list because everything starts with the science, but perhaps you were putting impacts first because this is such an important issue.
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One Planet Only Forever at 01:44 AM on 23 November 20242024 SkS Weekly Climate Change & Global Warming News Roundup #46
I have some additional adjustments of my suggested list of Primary Category headings for the Weekly News Roundup. Each primary heading should refer to the primary interest which is learning about everything related to Rapid Human-Caused Climate Change.
Climate Change Impacts: Environment-Social-Economic (interrelated)
Climate Change Mitigation and Adaptation: Intimately correlated. More mitigation requires less adaptation.
Climate Change Science/Research:
Public Misunderstandings about Climate Change: Disinformation and Misinformation
Climate Change Policy and Politics:
International Climate Change related Conferences and Agreements:
• UN Climate Change COPs
• UN Biodiversity COPsMiscellaneous (Other):
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One Planet Only Forever at 03:46 AM on 22 November 20242024 SkS Weekly Climate Change & Global Warming News Roundup #46
I would change one of the Primary Categories I listed @7. I had simply copied the category AI created for Weekly News Roundup #45. But I think the following would be better.
Public Misunderstandings about Climate Science: Disinformation and Misinformation
Also, when appropriate, a News Items should be listed in more than one Primary Category. This wouold particularly apply to news items reporting on climate sciemce and research that also would fit under another category.
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One Planet Only Forever at 13:51 PM on 21 November 20242024 SkS Weekly Climate Change & Global Warming News Roundup #46
A Climate Science Communications specialist could likely develop a better categorization. However, I compiled the following ‘primary categories’ based on the Weekly News categories created by AI in Weeks #43, 44, and 45 and the set of categories suggested by nigelj @5.
Climate Change Impacts: Environmental-Social-Economic (interrelated)
Climate Change Mitigation and Adaptation: Intimately correlated. More mitigation requires less adaptation.
Climate Science and Research:
Public Misconceptions and Climate Science: Disinformation and Misinformation
Climate Policy and Politics:
International Climate Conferences and Agreements:
• UN Climate Change COPs
• UN Biodiversity COPsMiscellaneous (Other):
The AI generated listings for Weeks #43, 44 and 45 also provide a large number of potential ‘secondary categories’.
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One Planet Only Forever at 08:32 AM on 21 November 20242024 SkS Weekly Climate Change & Global Warming News Roundup #46
I am reviewing the categories created by AI for Weekly News #43, #44, and #45. I hope to post a result soon.
However, I have noticed a problem that using AI did not solve. In Week #44 the first category was for COP16. This Week's list is dominated by COP29. The problem is the failure to fully describe the COPs. They are:
- UN Biodiversity COP16
- UN Climate Change COP29
That full understanding is clear when reading each article. But the category title should fully describe the content rather than require a review of the content to determine what is in the category.
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nigelj at 15:54 PM on 19 November 20242024 SkS Weekly Climate Change & Global Warming News Roundup #46
Possible categories are the science of climate change, climate projections, climate mitigation and adaptation, politics of climate change, the denialist campaign, and miscellaneous issues.
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One Planet Only Forever at 09:09 AM on 19 November 20242024 SkS Weekly Climate Change & Global Warming News Roundup #46
I agree with wilddouglascounty’s recommendation. Climate science communication specialists should be able establish a helpful set of categories for the Weekly News Items.
Part of my work as a Civil/Structural technical specialist in a major engineering organization was collecting reference information on a diversity of relevant topics. My approach was to use a high-level set of identifiable categories with General (or Other) for everything that did not fit in an established category. As the information accumulated I would create new basic categories for suitable groups of information from the General category. And when appropriate I would create sub-categories in the basic categories.
Though they would not be relevant for the Weekly News Items, here are some categories I had that were related directly to climate change (they indicate why I pursued learning about rapid human caused climate change):
- Loads and Forces: Wind; Rain; Snow; Ice; Range of Temperature Change
- Surface Runoff: Rain Intensity and Duration; Snow Melt Rates
- Foundations: Slope Stability; Permafrost (It was expected to remain frozen for centuries. So we tried to build on it in ways that would not cause it to melt.)
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BaerbelW at 03:36 AM on 19 November 20242024 SkS Weekly Climate Change & Global Warming News Roundup #46
Cleanair27 @2
Thanks for the heads-up regarding the broken link. It's now fixed (and goes to the same published paper linked to in my earlier comment about this topic.
As an aside (and most likely stating the obvious): if you are especially interested in peer-reviewed literature, our weekly compilation has "tons" of just that!
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Cleanair27 at 02:58 AM on 19 November 20242024 SkS Weekly Climate Change & Global Warming News Roundup #46
I am willing to accept that there may be a positive efficiency difference between using a stochastic parrot and a human, or humans, to hunt for relevant articles that readers of this site will find informative or even useful. I'm not entirely convinced, and the link in this Story of the Week post is broken regarding AI vs. human writing and illustrating work. And it sounds a little too much like the John Henry fable updated.
There is also the ethical question that comes with using the products of large corporations whose investors who don't give a fig about the climate impact of the energy use from running LLMs. What they want is to continue to capture huge swaths of surplus value from the labor of others (as the Marxists would call it) and use their profits to extract excess rent (as economists would call it) in the form of public policy that favors their interests.
I don't know what the best solution is for the humans working very hard to maintain this site. For my own purposes, the chronological listing of reports and articles is more than satisfactory. It is easy to sift through to find what interests me, which tend to be the peer-reviewed research. So please accept my thanks for all that you do to inform us. I accept that it is best to leave up to you how to improve the product and ease your burdens.
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wilddouglascounty at 00:07 AM on 19 November 20242024 SkS Weekly Climate Change & Global Warming News Roundup #46
You might check the May 2021 article out from PLoS One on Article level classification of scieentific publications. What came to mine when I skimmed this article is that for your purposes it might be worth getting a bibliometric analyst involved in your stable of volunteers and she/he might be able to take your latest batch of articles you want to post on the site and whip them into taxonomic shape in no time, categorizing them into clear categories without any AI involved. I suspect that there are some out there who would understand the carbon footprint issues that AI represents and could figure out a way to do it sans the energy intensive approach.
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prove we are smart at 07:44 AM on 14 November 202420 fact briefs published in collaboration with Gigafact!
What the heck, thought I'd do the quiz even knowing I would know that stuff now. Well, I got number 15 wrong and am so glad I did!
I was eventually led back to here- skepticalscience.com/argument.php?p=1&t=162&&a=297 you can learn so much from the informed comments. By the time I read the first 25 comments of that decade old post I had my information- In fact a link from number 25 commenter led me here- www.amazon.com/The-Alchemy-Air-Scientific-Discovery/dp/0307351793 ( looks like a good read)
Surprising facts and scientific knowledge, gotta luv Skeptical Science.
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Bob Loblaw at 00:27 AM on 14 November 2024Sabin 33 #2 - Are toxic heavy metals from solar panels posing a threat to human health?
LazyTeenager:
How carefully did you read the post?
Searching this page for "hail" finds four hits: three of them in your comment. The fourth hit is in the body of the article, where it says "Moreover, they are encased in tempered glass that not only withstands high temperatures, but is also strong enough to pass hail tests..."
How did you translate that to "hail proof"? Are the web sites you are looking at trying to claim that the solar panel industry is advertising that solar panels are indestructible?
A simple Google search for "solar panel hail damage resistance" finds a series of web pages that include statements such as "...can withstand most hail storms...". In addition, numerous web pages talk about how installation and solar panel type can improve hail resistance.
...and I even see web pages that mention various testing standards, for example:
"According to IEC 61215 standard, a PV module should resist at the minimum to the impact of a hailstone of 25 mm launched at 80 km/h, while the Swiss VKF standard demands a minimum of 30 mm, practically making it 40 mm or more."
...and one page that lists "8 ways to protect your solar panels from hail storm damage". Number 1 is:
Buy Panels Rated UL 61730, UIC 61730, or IP68
The first step to protecting solar panels in a hailstorm is to buy resilient panels. The materials that go into a solar panel’s manufacture determine its durability.
While most panels produced today are relatively tough, panels rated UL 61730 go through testing to withstand strikes of hail between one and three inches, traveling at speeds up to 88.3 miles per hour (142 kph). Purchasing panels that meet this certification level can protect your solar array in almost any storm.
So, the OP that states "strong enough to pass hail tests" clearly does not mean that solar panels are indestructible. If a particular installation has been done with poorer quality materials or methods, or a hail storm that is worse than expected and tested for, then damage will happen.
Choosing a less expensive panel or installation means taking more risk. Pictures of damage solar panels indicates that people took more risk that they realized, or didn't properly assess the risk - or simply lost the bet on whether the risk would happen to them.
So, the answers to your questions are readily available. The OP does not claim that solar panels will never get damaged, so photos of hail-damaged solar panels is not a contradiction.
