I’ve ended up in a rather silly discussion/debate on Twitter about the Greenhouse Effect. I realise it’s rather pointless, in that those who dispute it are very unlikely to accept its reality. However, it’s still interesting to think about how to construct an argument, and it gave me an opportunity to highlight some papers and articles that might be of interest to others. I thought I might repeat some of it here.
One of the arguments being made is that noone has demonstrated that CO2 can provide the backradiation that heats the surface. Firstly, it’s not simply CO2, it’s emission back to the surface from the lower atmosphere. Also, given an average surface temperature of around 288K, we know the surface must be radiating almost 400 Wm2. It also loses just over 100 Wm2 through evapo-transpiration and thermals (see energy balance figure on the right).
However, the surface receives less than 200 Wm2 from the Sun. Hence, to be in energy balance, there must be an additional energy flux, with a magnitude of over 300 Wm2. This is the back-radiation from the lower atmosphere. If it wasn’t there, the surface would be losing much more energy than it was receiving and would rapidly cool. This clearly is not happening, hence there must be some backradiation. I should add, that it has also been measured.
Another argument is that the effect of CO2 is now saturated. This is an old argument that has been addressed a good number of years ago. It illustrates a rather fundamental misunderstanding of the Greenhouse effect. What’s not always well understood is that convection in the lower atmosphere (troposphere) is important. Convection plays a role in the atmospheric temperature decreasing with increasing altitude; it gets colder as you go up in the atmosphere.
The presence of greenhouse gases in the atmosphere prevents all of the energy from being radiated to space directly from the surface. Instead some of the energy is radiated to space from within the atmosphere. Since the system will tend to energy balance, and since temperature decreases as you go to higher altitudes, this means that the surface has to be warmer than it would be in the absence of an atmosphere; the Greenhouse effect.
Also, as illustrated very nicely in the Figure on the right, taken from this Realclimate post, adding more greenhouse gases to the atmosphere increases the altitude at which energy is radiated to space. Again, since the temperature decreases with altitude, this would then require that the lower atmosphere and surface would have to warm to return the system to energy balance; the enhanced Greenhouse effect. This is what we’re doing now with our emissions of CO2, and other greenhouse gases.
A final claim is that most of our recent warming is due to increases in absorbed solar radiation, which contradicts what’s expected from the Greenhouse effect. This is a somewhat subtler point but, again, illustrates a misunderstanding of how the Greenhouse effect actually works.
A somewhat simplistic view of the Greenhouse effect is that adding greenhouse gases to the atmosphere reduces the outgoing longwave flux, which then recovers as the system warms back to equilibrium. However, as I explain in this post, there are both short- and long-wavelength feedbacks. The outgoing longwave flux actually recovers quite quickly. However, the shortwave feedback (mostly due to changes in clouds) leads to an increase in absorbed solar radiation, which causes the system to keep warming, increasing the outgoing longwave flux to above the level it had before the greenhouse gas concentrations increased.
So, in a sense, this continued warming is due to an increase in absorbed solar radiation, but this doesn’t mean that this wasn’t caused by the initial increase in greenhouse gases in the atmosphere. It doesn’t somehow contradict what we expect from the Greenhouse effect.
Anyway, I think it’s useful to think about these things even if arguing about it on Twitter is mostly pointless. A key point, which I’ve probably highlighted before, is that if someone thinks they’ve encountered some simple, and obvious, reason why a well accepted scientific argument is flawed, maybe they should first check that they properly understand the scientific argument they claim to have overthrown.
...and Then There's Physics 
That argument can be traced in the science record to Rasool & Schneider’s 1971 paper, where that’s exactly what they argued from a highly simplified 1D model. It took only “moments” (a few months of real time) for letters to arrive pointing out fatal problems (I can report on those, as I still have my notes from decades ago) and, also, so did the authors themselves find still more. The upshot of that paper is that its conclusion about CO2 was wrong but that it did help push along the concept of aerosols. So, it’s still an important paper in a long line, despite a flawed conclusion about CO2.
The point I’d like to leave here is that earlier papers very often take necessary simplifications. Especially in climate, which is very complex and back in 1971 still had a great deal of work ahead. But that these simplified views, when fundamentally flawed, are often corrected quite soon, if not later, through the normal course of scientific dialog. In this case, scientists (and the authors themselves) quickly realized significant problems and rapidly corrected key errors.
That said, I can also see why disingenuous individuals might continue to capitalize on this very old story when speaking to others who may lack training in the processes of science and how the “sausage gets made” and who may also not have learned to respect the highly interwoven nature of science knowledge.
Don’t you just have to put out an infrared spectrograph at the Earth’s surface and measure the energy it receives per unit wavelength?
We know for sure there is a greenhouse effect because there is experimental proof of it: satellites in Earth orbit measure less heat escaping out to space, at the particular wavelengths at which CO2 and other GHGs absorbs radiation. Moreover, this outgoing radiation is decreasing, and at the wavelengths predicted by greenhouse gas theory, just as expected since we are adding greenhouse gases to the atmosphere:
“Increases in greenhouse forcing inferred from the outgoing longwave radiation spectra of the Earth in 1970 and 1997,” J.E. Harries et al, Nature 410, 355-357 (15 March 2001).
http://www.nature.com/nature/journal/v410/n6826/abs/410355a0.html
“Comparison of spectrally resolved outgoing longwave data between 1970 and present,” J.A. Griggs et al, Proc SPIE 164, 5543 (2004). http://spiedigitallibrary.org/proceedings/resource/2/psisdg/5543/1/164_1
http://tinyurl.com/knoa4dy
“Spectral signatures of climate change in the Earth’s infrared spectrum between 1970 and 2006,” Chen et al, (2007)
https://www.eumetsat.int/cs/idcplg?IdcService=GET_FILE&dDocName=pdf_conf_p50_s9_01_harries_v&allowInterrupt=1&noSaveAs=1&RevisionSelectionMethod=LatestReleased
http://tinyurl.com/mb4xz38
“Radiative forcing – measured at Earth’s surface – corroborate the increasing greenhouse effect,” R. Philipona et al, Geo Res Letters, v31 L03202 (2004)
http://onlinelibrary.wiley.com/doi/10.1029/2003GL018765/abstract
“Measurements of the Radiative Surface Forcing of Climate,” W.F.J. Evans, Jan 2006
https://ams.confex.com/ams/Annual2006/techprogram/paper_100737.htm
Why don’t these suffice?
Don’t miss PBS Frontline’s The Power of Big Oil (Part One: Denial) , a four part six hour multimillion dollar effort ten yeasrs in the making aimed at convincing us that for a generation the world paid more attention to Pat Michaels and the Koch brothers ten year multimillion dollar advertising effort than Al Gore and Bill Moyers’
RC is going to have a field day, but’ I fear ClimateBall didn’t make the cut in Part One.
David,
Yes, those should more than suffice. However, you’re probably also aware of the experts on Twitter who can find any reason to dismiss something that doesn’t quite suit their narrative.
Jon,
Yes, one of those on Twitter highlighted that paper to support their argument. I found some of the subsequent papers.
Indeed, the scientific endeavour is a process. We learn from our mistakes as well as from our successes.
David, IR spectrophotometry is complicated by a range of emissivity issues – black bodies are rare ,and beyond the proverbial fifty shades of gray , some common cloud and aerosol molecules and materials display vibrational reflectivity peaks in the thermal IR
That’s a very nice and useful summary of the theory of the CO2 Greenhouse effect.
It took me ages to twig (understand) this mechanism, which seems a sound mechanism. I think it took me so long to understand because for the most part because it is a very poorly understood and explained effect even in pro AGW circles.
It seems to me that it behoves all of us to tread carefully though?
Mapping the thermodynamic profile of the whole atmosphere is a complex area, and there are multiple feedback loops?
Has anyone reviewed the following issue for example?
Is there an IR feedback loop from the downwelling IR from the Stratosphere to the upwelling IR from the Troposphere via the Tropopause? It’s a loop I have not bottomed out, or seen discussed? Does the Stratosphere-Troposphere IR downwelling feedback loop affect the temperature of the Troposphere, or can we ignore it? The Stratosphere IS cooling (it has been measured, I believe?), from which the downwelling IR from the Stratosphere to the Troposphere at the Tropospause (one would extrapolate) is reducing …..
One question underlying this is where is the ‘outer’ point of the atmosphere? Troposphere? Stratosphere? Thermosphere? Exosphere? And how big and variable are the effects of the upwelling and downwelling IR at various points within the atmospheric column? From which point in the atmospheric column does the IR actually exit the atmosphere? We know the temperature within the whole atmospheric column varies depending at which point it is measured? Stratospheric temperature rises with height, unlike the Troposphere, so the opposite happens in the Stratosphere, ie MORE IR is irradiated upwards at the highest point because it is hotter (one reason it is cooling), unlike the Troposphere bottleneck where LESS IR is irradiated upwards? But of course the atmosphere, and the CO2, thins with height.
My point really is that the atmosphere really is a complicated thermodynamic-energetic system, and I am not sure any of us understand it completely? But there sure are better and worse models.
Perhaps someone has already thought this through, and this issue has been discussed, but it strikes me that what makes the atmosphere so fascinating is it’s complexity?
Peter,
There isn’t really a single altitude. If you assume an average surface temperature of 288K, an emitting temperature of 255K, and a lapse rate of 7K/km, then on average it’s being emitted from an altitude of about 5km. However, it is wavelength dependent. There is an atmospheric window, so some is emitted directly from the ground. There is some that is actually emitted from within the stratosphere. And then there are some bands that are emitted from within the troposphere. On average, however, the outgoing flux is equivalent to a blackbody with a temperature of ~255K, which would be a typical temperature at an altitude of about 5km.
I’m not entirely sure about this. My suspicion is that these regions are optically thin, which means that they both absorb and emit inefficiently. Hence, I suspect it can probably be ignored.
Jon Kirwan says:
Another argument is that the effect of CO2 is now saturated.
That argument can be traced in the science record to Rasool & Schneider’s 1971 paper
Minor historical point, but the CO2 saturation argument goes back to at least Ångström’s rebuttal following Arrhenius’s calculations. Ångström was mistaken to a first order approximation because of the “effective radiating level” concept noted by ATTP and to a second order because of absorption band widening in pressurized gas.
lThe Carbon Dioxide Greenhouse Effect: Skepticism (1900-1940s)
There is a diff between those that deny that CO2 is a factor at all and those that claim CO2 is at a saturation level, as the latter requires the role of CO2 as a GHG. On another level there are those that reverse the causation, claiming that excess CO2 results from increasing temperature. So three modes of skepticism
CO2 => T but weak or saturated
CO2 no role as it violates laws of thermodynamics
T => CO2 strong due to thermodynamics
As Eli Rabett commented in the Twitter thread, when one looks at the context, their arguments fall apart. They really all should argue amongst themselves.
Paul:
Thanks to compartmentalization,
https://en.wikipedia.org/wiki/Compartmentalization_(psychology)
…it is quite possible for someone in denial to believe completely contradictory arguments. The example you give (CO2 has no effect/CO2 is saturate) goes along with back radiation violates thermodynamics/water vapour is the strongest greenhouse gas, the temperature record is unreliable/the temperature record shows cooling, etc.
It’s not a bug in denialism, it’s a feature.
Nice one, Bob.
Compartmentalization can’t explain that kind of things, tho:
https://www.drroyspencer.com/2022/04/uah-global-temperature-update-for-march-2022-0-15-deg-c/#comment-1252785
That silly sock puppet has been repeating “ice cubes can’t boil water” every single day since at least a few years at Roy’s.
“ice cubes can’t boil water”
Sure they can, if you have a heat pump running. Does that sock puppet have an explanation for how air conditioners can cool inside air to 20C by dumping energy outside to air that is at 35C?
Simple answer: there is more involved in energy transfer than just temperature. Compartmentalization allows the sock puppet to ignore everything else that is involved, isolating the “argument” to a restricted set of “facts” that help them avoid cognitive dissonance.
https://en.wikipedia.org/wiki/Cognitive_dissonance
P.S. I also know how to unscramble an egg.
Bob,
Of course that sock puppet has no answer to anything. He still pretends he does, in fact he’s been promising one for a week now:
https://www.drroyspencer.com/2022/04/uah-global-temperature-update-for-march-2022-0-15-deg-c/#comment-1248532
Which brings me to the following idea. Whatever cognitive process is behind that kind of behavior, it fails for pragmatic reasons. In a nutshell, Roy’s sock puppets excel at breaking communication channels. They’re so good that some of them keep breaking pragmatics each and every single day for more than a decade.
Hence why addressing their points over and over again fails. These exchanges are not about content. They’re about manners.
Manners maketh the Climateball player.
Another way to make the same point. Take this typical misconception:
“But climate changes” does not fail because it’s false, but because it’s silly. Nobody argues that climate does not change or that we should prevent the climate from changing. Truth does not imply relevance, and in an argumentative setting relevance is key.
Worse is that Judy fails to mention the subtext to the claim, e.g. that CO2 may not drive actual climate. This is the misrepresentation.
And that’s notwithstanding Judy’s “But Consensus” bait.
The Morton’s demon is strong in that one, Willard.
https://rationalwiki.org/wiki/Morton%27s_demon
…and Judith has compartmentalized the issue to eliminate the context/subtext.
In reading the twitter exchange, I see that she does not notice the hypocrisy of accusing others of leaving things out (IPCC) while failing to recognize that leaving things out destroys her own point. I guess those others leave things out [because advocacy], while her posts are [no advocacy here. Move along]. A world with no mirrors.
Chris Colose’s unsuccessful attempt to illustrate the basic problem with Judith’s argument was quite amusing.
Ahh, the true politician at work. Say something that avoids saying the message you want your supporters to hear, but leads them there anyway. Plausible deniability – “I never said that”. Done well, different people with violently different opinions will all hear the message they want to hear, and think the politician is on their side.
https://en.wikipedia.org/wiki/Plausible_deniability
https://en.wikipedia.org/wiki/Dog_whistle_(politics)
Willard – ““But climate changes” does not fail because it’s false, but because it’s silly.”
It looks to me like the natural susceptibility of our climate system to change a lot from relatively small initial changes – eg orbital cycles, greenhouse gas concentrations – is why dumping giga-tonnes of CO2 into the atmosphere does have such significant impacts. I find it worth pointing out when this argument arises that it would take a climate system that doesn’t change for it to not matter. It looks like the hook of the argument is the suggestion the changes could be natural – but that only really works with those who already believe – or prefer to believe, or want others to believe – it not anthropogenic.
Russel – “- aimed at convincing us that for a generation the world paid more attention to Pat Michaels and the Koch brothers ten year multimillion dollar advertising effort than Al Gore and Bill Moyers’”
I don’t know about the doco in question, but the influence of captains of commerce and industry reach far beyond that of mere advertising to misinform the public; they have direct access to and the close attention of politicians and political parties that ordinary citizens or climate activist organisations do not get. My list of the tools of persuasion available to them – besides advertising and PR aimed at muddying public opinion – include lobbying and direct influence, strategic donations, post political career payoffs, tactical lawfare and tankthink. Alarmist economic fear – of the solutions being worse than the problem and sometimes with threats of economic paybacks by shifting investments elsewhere if emissions reductions are demanded of them – has been a powerful meme, that works directly on politicians as well as with the public. But just keeping Doubt and Denial alive has been surprisingly successful at inducing Delay.
mrken,
Yes, it is rather ironic that some who argue that the climate isn’t sensitive to quite large changes in atmospheric CO2 concentrations is somehow very sensitive to really small changes in solar flux, of solar magnetic field, or cosmic rays, or ….. It certainly seems like a “anything but CO2” type of argument.
You actually sound as, erm, perplexed as I am (!)
That is what makes this so interesting, because it is so complicated.
If, for example, the Stratosphere is cooling, and it IS (isn’t it – I think NASA measurements confirm this ?) – then the downwelling radiation from the Stratosphere to the Troposphere is less (?).
How much less is the question, isn’ t it?
I can’t even get my head around the ramifications to be honest.
I think there are a number of scenarios
1) The raised emission height (EEH) in the Troposphere is creating an energetic bottleneck due to reduced upwelling radiation at Top of Troposphere (or from Av 5km, whatever), causing warming at the earths surface. (Ie normal AGW theory).
2) The reduced downwelling radiation from the cooling Stratosphere balances out the reduced upwelling radiation from the Troposphere, meaning a nil overall energetic effect. No warming.
3) It is even possible reduced downwelling IR radiation from the increased CO2 in the Stratosphere is greater than the reduced upwelling IR from the Troposphere, which might actually have a cooling effect. Sure, that doesn’t seem to fit the bill, but at least I would say it needs modelling?
4) My ideas above are nonsense, and there are better ones !
I think there is a great deal of confusion about where the TOA, Top of Atmosphere, actually is? For ages I was equating it with Top of Troposphere, about 10miles up, and I think that is exactly what you do in your reply to me, coming up with the 5km figure for where IR ‘leaves’ Earth’s atmosphere. I think the 5km is correct for IR that ‘leaves’ the Troposphere, but NOT for the IR leaving Earths atmosphere as a whole? The idea of a Troposheric energetic IR bottleneck is fine, but it is not the whole story?
And what makes this so mindbendingly complicated, is, as you point out, IR radiation actually leaves the earth from very many layers, including the Earth’s Surface itself, which I believe emits 50% of all IR direct to space because H20 and CO2 only block certain windows of IR wavelengths. (That is a bit of a side issue here. Let’s deal with the 50% that is absorbed !)
So I know I have left what is effectively a mess, and a really unclear picture, but until someone models the whole grey-body/black-body IR profile of the whole of the atmospheric column up to at least 100000km, or even 0.5Mkm or wherever our atmosphere peters out (or at least the CO2 part of it), instead of just the first 10miles of the Troposphere, I don’t think the modelling is complete? Absorbtion/Emission Upwelling/Downwelling goes on throughout the whole 100000km + column and we need a better understanding of that before making assumptions that we can just ignore the upper atmosphere ?
Just creating confusion I suppose, but climate science is both fascinating and perplexing I find. It takes a strong mind to admit they don’t understand all of it? That’s why we all need to tread carefully.
If anyone has seen an analysis of this issue, it would be great to see it. I know Clive Best did a kind of reverse analysis of radiation incoming to the Stratosphere. Even just to show my points are nonsense?
Peter,
If the stratosphere is cooling, then it’s losing more energy than it’s gaining, so you might expect the emission from the stratosphere to have gone up (which I think is the case). However, the heat capacity of the stratosphere is pretty small, so I don’t think this is all that relevant when it comes to the energy balance of the climate system.
In this context, i think the TOA was introduced to distinguish between surface fluxes versus fluxes into and out of the whole climate system. My understanding is that some early work on climate sensitivity suggested that it would be quite low. The reason was that the were calculating how a change in atmospheric CO2 would influence fluxes at the surface. Because adding CO2 to the atmosphere increases the downwelling long-wavelength flux, they concluded that it would only take a small amount of surface warming to return the surface to flux balance. What they didn’t appreciate is that this wouldn’t return the system to flux balance, which they would haver realised had they been considering TOA fluxes, rather than surface fluxes. So, the TOA is really just an altitude at which if the incoming and outgoing fuxes balance, the system should be in equilibrium.
From Ray Pierrehumbert’s ghg video. To raise the earth’s temperature 2C, with a 6-7C per 1000m lapse rate, need an increase in the effective radiating height of roughly 300 meters, about a 6% increase. A rough calculation, but shows that it doesn’t take much of an increase in radiating height to change the climate.
https://t.co/C9pRHXM6eF
Chubbs,
Thanks. Yes, if the lapse rate doesn’t change (which is a reasonable approximation) then raising the average emission height by 300m would lead to warming of ~2C.
In the stratospheric cooling case, you need to remember that adding CO2 increases both absorptivity and emissivity. More IR is absorbed, but you can also emit more IR at the same temperature. In the troposphere, increased absorptivity dominates. In the stratosphere, IR absorption isn’t as much of an issue, so the increased emissivity means the same IR emission can happen at a cooler temperature. High stratospheric temperatures are related to high UV absorption, not high IR absorption.
You need to include all the complexities – not just a small subset.
I’m very happy to admit this issue may be a red-herring, and pointless dead-end, but until someone does the mathematical modelling, for me I don’t think I can ignore it or it completely goes away, for me anyway?
Maybe the modelling has already been done, and I’ve simply missed it?
The key issue for me seems to be how much IR is absorbed within a certain distance given a certain density of CO2 This seems key to establishing from what approximate point IR finally leaves the CO2 cloud surrounding the earth to outer space? The idea of TOA being some kind of balance point between upward and downward flux doesn’t seem that clear or helpful trying to model what is going on?
The approximate height at which IR leaves the atmosphere is key to whether Earth is cooling or warming? I think the upper atmosphere deserves attention. And the answer is pretty horribly complex isn’t it, because IR exits the Earth’s atmosphere from multiple levels and points. What we need to do is work out how much from each level, some kind of integral equation?
On tope of this it seems to me there are series of flux-feedback loops between the upper atmospheric layers that probably requires a sophisticated bit of computer modelling and iterative calculation to bottom out where any final thermodynamic equilibrium point is, or where the internal system temperatures settle down to once we change conditions such as add CO2 to the whole atmosphere up to 100000km+ ?
I am not even sure the effect of much of this has been studied scientifically, eg CO2 in the Exosphere? Is there any CO2 in the Exosphere?
I think the flux calculations you originally alluded to seemed to apply the lapse rate in the Troposphere? And this works fine and is valid for the Troposphere, and sure, most of the CO2 is in the Troposphere, but not all and the Tropospheric lapse rate doesn’t apply to the whole atmosphere. 6.5 degrees per km or so is the fall in temp in the Troposphere up to 15 km or so?
The current model which you outlined and AGW uses is :-
– as the CO2 in the Troposphere get’s thicker, the EEH Effective Emission Height raises, so the EEH goes upward to a lower temperature point, so less IR is emitted from the Troposphere upward, overall.
I find this effect weird and wonderful, but it is effective and credible?
But there are numerous temperature gradients in the upper atmospheric layers. The Stratosphere gets hotter as you go higher that causes it to emit MORE IR, (and thereby causing cooling?) This lowered Stratospheric temp will change the downwelling flux into the Troposphere and so influence the temperature in the Troposphere, won’t it?
And there are further temperature gradients the higher you go in the atmosphere.
The question for me is I want to know how much IR flux is absorbed in the higher layers, and how much escapes earth and from what (average?!) point?
I have not seen this modelled but maybe I was looking in the wrong place?
Can we exclude the whole of the upper atmosphere and go with 5km as the average point of IR emission from CO2 to outer space? Is all 100000km+ of upper atmosphere negligible?
Maybe it already has been and this whole conversation is a rehash of previously explored avenues. Please forgive if it is.
As you say, the upper reaches of the atmosphere might be so rarefied and sparsely populated with CO2 that they have very little impact on the whole picture? But there is a lot of it, maybe even 0.5M miles of Exosphere? Then again CO2 might not be present higher up, it is heavy molecule?
That explanation sits well with me if true and proved, but I think the whole 100000+km of atmosphere needs modelling to get the full flux and IR-shedding picture, rather than assuming we can ignore everything above the Troposphere, after the first 15km or so? I haven’t seen this flux-exit picture done. It would result in a fairly complicated Thermodynamic/flux model?
Anyway, enjoyed the chat, hope you did, really interesting site. Wish I had the maths to calculate the effects of the rarified CO2 on IR flux in the upper atmostphere. Maybe one day get the Raspberry Pi working on that !
And it is very refreshing to talk science, or at least burble (!) I hope I have had a go at? I think so often these discussions reduce themselves to agenda-bashing and misunderstanding rather than understanding potential mechanisms behind climate?
Peter,
I’d be surprised if it hasn’t already been done, but I don’t have an obvious source.
I also think you’re over-complicating things. We know the Earth is warming because of all the indicators of warming (GMST, ocean heat content, loss of ice mass, etc.). This tells us that the climate system is receiving more energy than it is losing.
We also have a very good understanding of the various process associated with this warming and that currently it is primarily a consequence of increasing greenhouse gases in the atmosphere. It is, however, complex and so any attempt to explain this is going to simplify things to some extent.
So, in some sense, I’m not quite sure what it is that you’re questioning.
The following is a very rough fag-packet calculation of absorption of IR by CO2 within the atmospheric column up to 20km.
It suggests the upper atmosphere absorbs most if not all of the IR emitted by the lower atmosphere.
At least to 20km. And suggests that the cloud of CO2 around the earth actually sheds IR from much higher up, not from 5km?
To my viewpoint this suggests the current AGW model is way too simple.
I know it doesn’t need complicating any more, it is already complicated enough, but this is where my thinking is taking me ..
Any IR shed by CO2 in the atmosphere needs to avoid being re-absorbed by all of the CO2 above it in order to escape to outer space ?
FAG PACKET CALCULATION –
The atmospheric density at 20km high in the Earth’s atmosphere is 1/15th that at sea level in kg/m3.
https://www.pdas.com/atmosTable2SI.html
All Terrestrial IR is absorbed by CO2 at sea level within 10m of the surface.
http://nov79.com/gbwm/satn.html
That is a climate sceptic site, please replace with better info? It was the best I could find in a short time. What is the true absorption distance for IR at sea level ?
30m was a figure I had in mind if that is more acceptable?
– it is the density of the CO2 that determines how much IR is absorbed, by the CO2 around it, would you agree?
This concept is the premise that AGW theory of climate change is predicated on.
Higher concentrations, denser CO2 means more IR is absorbed, this driving the effective emission height higher?
So, doing a very rough fag-packet calculation, any IR emitted by CO2 at 20km will be absorbed within 150m?
15 times longer at 20km hight than at sea level because the CO2 is 15 x less dense.
Or 450m if we use 30m as the absorption distance.
(Ok, very very very approximate and rough calculation!)
I think this suggests that there is enough CO2 in the upper atmosphere to absorb all upwelling IR from the CO2 beneath it up .
This really, really rough fag-packet calculation suggests the idea that the average emission height for IR emitted by CO2 into outer space being 5km is wrong, doesn’t it?
In fact, it seems to show a really big discrepancy.
(Can we revisit how the 5km figure is being calculated?)
At a rough guestimate using the figures above, all IR emitted at 5km is probably re-absorbed within 75m at a guess. None ever reaches outer space.
I’ll happily admit this is nonsense if the science says so, but the question is, what picture does the science modelling actually say ?
To my mind, it is a question of the distance the IR takes to be absorbed by a given density of CO2 that is key.
AGW theory is based on the average height of the upwelling emission of IR being raised within the Troposphere because the CO2 density is thicker, 400 ppm not 280 ppm.
This theory makes sense to me.
It is a very interesting and good model.
But the figures I outlined above do NOT show that this is the point at which IR is shed from the earth’s atmosphere into outer space? These figures would suggest that happens much higher up?
And that leaves a much more subtle and complicated picture than previously assumed.
There may well be a flux bottleneck at the top of the Troposphere.
But that is not the point at which the cloud of CO2 around the earth sheds IR into outer space?
What we need to do is back-work the thermodynamic picture from where the CO2 actually sheds IR into outer space. Which could well be the Exosphere or Thermosphere. Has this modelling been explored? Simply taking the TOA as the Top of the Troposphere only gives part of the flux picture, and would appear to be misleading partial picture as a guide to the Thermodynamics of our climate?
So that is where my thinking takes me, trying to model the absorption and emission of IR by CO2 throughout the whole of the atmospheric column at least to 20km?
Please double-check any figures as they are simply grabbed off the internet.
Peter,
It might be worth you looking at modtran. You can vary various parameters and you can see what the outgoing spectrum looks like. The effective temperature at which the radiation is coming from tells you something of the height in the atmosphere from which it is coming. Some does indeed come from quite high in the atmosphere, but some comes directly from the surface.
“All Terrestrial IR is absorbed by CO2 at sea level within 10m of the surface.
http://nov79.com/gbwm/satn.html
That is a climate sceptic site, please replace with better info? It was the best I could find in a short time”
If atmospheric optical depth were that high, IR imaging would be as spatially limited as underwater photography . It is not., witness this IR landcape with towering IR poaque nethane plumes :
https://vvattsupwiththat.blogspot.com/2015/12/infrared-ink.html
Russell,
AGW theory is predicated on there being an optical depth for IR emissions from CO2 isn’t it?
The EEH, effective emission height increases due to IR being absorbed by CO2.
If you deny there is an optical depth, aren’t you denying AGW exists?
What would be really helpful would be an idea of what the optical depth is?
I did say my info was just from a quick search on the internet.
Do you know what the absorbtivity of CO2 at a given density to IR is?
All we need is a figure to do a fag-packet calculation?
I don’t mind being shown to be wrong at all so if you have some science please share ?
This is a modelling issue I would simply like discussed?
By the way CO2 only absorbs a few wavelengths of IR, not all of them ?
About 50% of IR escapes from the earth’s surface directly to outer space as far as I know.
So despite being shrouded in CO2, the Earth’s Surface would show on an IR imager in outer space I guess?
Thanks I will take a look at modtran shows.
I do think this issue could do with a hearty discussion.
Then again, I have been utterly wrong on other things (!)
Short answer for Peter is “yes, it’s been done”. The MODTRAN link ATTP provided is a medium resolution model for IR. It has the advantage of having an on-line version you can play with.
There is a higher resolution model call HITRAN. (surprise!)
https://hitran.org/
Basically, codes differ in the degree of spectral radiation, and then you get to decide how many atmospheric layers you want to use in a particular application.
In a climate model, you would be unlikely to have as many layers, and would use simpler approximations, but those approximations would be verified against the more retailed models. As it is, radiation calculations eat up a lot of CPU cycles in a climate simulation.
> It was the best I could find in a short time.
Then perhaps you’d need to work a bit more before a hearty discussion can take place, Peter.
Thanks Bob, it sounds like I need to get my head around the Modtran algorithm if I want to understand the modelling they are using.
There have been a lot of very bright people working on this for a number of years, so to some ears my questions might sound primitive. That was the case when I first understood the EEH (Elevated Emission Height) which, to be honest, it is tricky to explain, and again, I don’t think many people understand it very well.
I do want to bottom out the discrepancy between the mean free path of a photon within a CO2 cloud, which appears to be between 10m and 100m, or of that order, as far as I can make out, at least up to about 15km, or so it appears, and the fact that the modelling claims that the EEH is about 5km. At 5km it means the photons are travelling on average about 15000m, which is a lot more than 10m or 100m.
That might be true if the direct emission of IR from the Earths surface is included, but if it is, then I don’t think that measurement is very useful at all. What seems important to me is only the emission height of the IR out of the CO2 cloud to the AGW discussion? For the EEH model to be useful and work, the change in emissions from the CO2 cloud needs to happen, for the most part, below the Top of the Troposphere.
russellseitz wrote:
David, IR spectrophotometry is complicated by a range of emissivity issues – black bodies are rare ,and beyond the proverbial fifty shades of gray , some common cloud and aerosol molecules and materials display vibrational reflectivity peaks in the thermal IR
Oh please Russell. Definite OLR changes at precisely the wavelengths where the major GHGs absorb IR are not seriously complicated by “emissivity issues” — especially when they match up precisely with what theory predicts.
You’re trying way too hard.
Peter:
I’m not sure what you mean by “a CO2 cloud”. CO2 molecules are just some of the molecules mixed in with every other molecule/gas in the atmosphere, and the processes of absorption and emission of radiation are processes that occur on a single-molecule level. One photon at a time will interact with one molecule at a time. As soon as you get into energy totals and such you are looking at the sum of many photons and many molecules, but the basic nature of the process is still one photon and one molecule.
As such, absorption coefficients and optical depths, etc. are probabilities. One photon will either make it through – or not. Photons do not get half-absorbed, or partly absorbed at this point and the rest absorbed at that point. Likewise, when you see a photon arriving at some height, the photon (and you) have no knowledge or memory of where it was emitted – it’s just a photon with this wavelength and that quantity of energy (based on its wavelength).
More CO2 in a given volume or distance means higher probability of an IR photon (at the right wavelength) getting absorbed. A higher probability of getting absorbed means a lower probability of being transmitted.
The Beer-Lambert Law is the one that typically describes absorption. Perhaps the following post at Skeptical Science will explain some of the basics of how it is used:
https://skepticalscience.com/from-email-bag-beer-lambert.html
[Of course, I am somewhat biased about the utility of that post.]
“Don’t you just have to put out an infrared spectrograph at the Earth’s surface and measure the energy it receives per unit wavelength?”
Sorry David, but you’re thinking about the wrong sort of instrument spectroscopes measure wavelength, but it takes instruments with flux comparing optical paths – IR spectrophotometers , to quantify how much energy gets to an illuminated surface. If you think about the mass similarity of dimilarly bonded functional groups in low MW vibrationally active gases , and how pressure broadening blurs line spectra into often overlapping peaks, you’ll find that light element molecules and aerosols- ice , ozone, silica, and carbonate dust all add complexity in time and space to radiative transfer in the IR.
Many chemistry and atmospheric science departments have STEM liason programs that demonstrate how their instruments work, and finding out can be as worthwhile as reading the literature that depends on them .
Thanks again Bob.
My sense is that the CO2\IR flux modelling is not sophisticated or subtle enough.
I agree that in the Troposphere with a regular lapse rate there WILL show a raise in Effective Emission Height (EEH) for any IR flux emitted within the CO2 IR window (15mu) if the molar density of CO2 increases, and if we stay BELOW the top of Troposphere.
But forgive me I am sure you also get the concept of mean average path or mean average distance of travel of a photon? It is a common concept in thermodynamics and is used for gamma rays. I am using it for IR radiation in a CO2 cloud of given molar density? And yep we could probably characterize it in quantum language too as the mean distance of a quantum leap (or event) of a photon between molecules if we wanted to? Despite the photons not knowing or caring about their own origins, statistically it works, which is all that matters?
I make this distance, from what I have read, between 10m and 30m at sea level? Does that make any sense? Either people will understand and go with that or not. I am happy to be put right but I think that concept is fairly well accepted?
What I see is an enormous gulf between the notion that the EEH for IR emissions into outer space caused by CO2 being claimed to be at 5km, with a further 100 to 500000 further km of atmosphere to travel upwards through to escape into outer space, while the mean average distance of travel of a photon in the CO2 IR wavelength window, at sea-level molar density is 30m before being reabsorbed, probability-wise or however by another CO2 molecule.
Something just is not right, is it?
IR can’t travel 30m on average one minute, and 100km on average the next?
In fact if IR really could pass through 100km of atmosphere without being reabsorbed, there would not be any greenhouse gas effect to worry about? How is it possible to imagine that the EEH into outer space in the CO2\IR window is at 5km? That would mean half the emissions were even lower, and never reabsorbed by all the CO2 above, wouldn’t it? Where have the Greenhouse Gases gone?
And yes sure the atmosphere gets much less dense the higher you get, there are many variables, but nothing that currently explains this huge discrepancy?
It might be a phantasm, it might be a bit of cheese I ate, but that is what doesn’t quite fit with the current EEH paradigm for me?
The raised EEH below the Top of Tropopause, where the lapse-rate ceases, is a real effect when the molecular density of CO2 increases, but all the other ramifications have not been modelled in enough detail through the whole atmosphere, including the upper atmosphere?
We need an even more sophisticated model to work out where the final EEH into outer space is for the CO2\IR window when we take into account the whole atmosphere including the upper layers?
@-P.D.Grimshaw
“Any IR shed by CO2 in the atmosphere needs to avoid being re-absorbed by all of the CO2 above it in order to escape to outer space ?”
IIRC the vast majority of IR absorbed by CO2 is transferred as thermal energy to the rest of the non/low emitting molecules in the atmosphere. Otherwise you would get superheated CO2 and H2O with very cold O2 and N2.
The bulk thermal energy of the atmosphere is then the component that carries out the transfer of energy from the surface to a point when it can be emitted without being rapidly re-absorbed and lost as IR electromagnetic energy to space.
Good point Izen—
Higher tends to be clearer, and the mesosphere is very clear indeed
Peter,
You keep implying (I think) that there is some single EEH. There isn’t. If you consider a typical MODTRAN output then you can see that some of the emission is coming from regions that are hot (close to the surface), some is coming from regions that are quite cold (near the stratosphere) and the rest is coming from regions within the troposphere. However, overall, the amount of energy radiated into space is equivalent to a blackbody with a temperature of 255K, which is the typical temperature in the atmosphere at ~5km.
Peter,
Also, in terms of photons escaping to space, you can think of photons as having a mean free path that depends on the density of the material through which it’s travelling. When the density is high, the mean free path is low, and the photons are absorbed/scattered regularly (although, as Izen points out, a lot of the energy is actually transferred through collisions, rather than simply through photons being absorbed and re-emitted). As the density goes down, the mean free path goes up and they travel further before being scattered/absorbed. Eventually, they get to an altitude where the density is low enough that most of the photons will escape into space before undergoing another scattering/absorption event. Additionally, this will be wavelength dependent, so the height at which this happens will depend on the wavelength of the photon. It also doesn’t mean that layers above this height can’t scatter/absorb any photons. It just means that it doesn’t happen very often. Layers above will also radiate, but the density is low enough that it doesn’t emit much and this is not energetically all that relevant.
One way to think of this is to consider the Sun. The photons are generated in the core via nuclear fusion, and then diffuse their way from the core towards the surface (with convection also playing a role in energy transport). The inner parts of the Sun are very optically thick, and so the photons don’t travel very far before being scattered/absorbed. However, when they get to a layer where the optical depth is of order unity, they can largely free stream into space. There is still a lot of atmosphere above this layer, and it is actually still hot, but it doesn’t absorb/emit many photons. When we point a suitable telescope at the Sun, what we see is the layer from which the photons can escape. We can’t see deeper than this, because the photons are still being regularly scattered/absorbed. However, if we look at a different wavelength, we will see the Sun having a slightly different size because the photons will be escaping from a slightly different layer.
in a sense something similar happens on the Earth. Photons are emitted from the surface, and the energy travels through the atmosphere until it reaches an altitude where the photons that can be emitted can largely free stream into space. This altitude depends on wavelength, and when you calculate the total amount of energy emitted into space it is the same as a blackbody with a temperature of 255K, which is roughly the same temperature at an altitude of about 5km in the atmosphere.
I thought the reflection of IR from the sky had been directly observed:
https://phys.org/news/2015-02-carbon-dioxide-greenhouse-effect.amp
Rob,
Yes, it has (although this was, obviously, disputed by those on Twitter who were insisting that we needed to demonstrate the existence of backradiation). I did actually link to the paper that that article highlights in the post.
Peter Grimshaw:
A search term to try is “effective radiative forcing” or “ERF”. There are several ways to calculate it but it’s what you describe. All these interesting feedback loops, the effect of the stratosphere etc are included in the IPCC headline numbers.
Some other stuff: HITRAN is a spectroscopic database, it records how gas absorb at each wavelength. MODTRAN is a code that solves the equations of radiative transfer. I’ve only ever used it with the HITRAN database but you can probably use a different one.
Peter’s questions about the stratosphere also apply to changes in solar output. When the Sun gets hotter, ozone in the stratosphere absorbs so much UV that it warms up quickly. There’s a rapid increase in outgoing longwave from the stratosphere that offsets some of the extra solar heat.
This contributes to why solar “effective radiative forcing ” is smaller than the “instantaneous radiative forcing” you would calculate from something like MODTRAN alone.
Mark,
Thanks. I’d forgotten that the ERF corrects for these effects.
Aren’t you guys just arguing about Lapse Rate?
Peter: Something just is not right, is it?
IR can’t travel 30m on average one minute, and 100km on average the next?
In fact if IR really could pass through 100km of atmosphere without being reabsorbed, there would not be any greenhouse gas effect to worry about?
Again, you are confusing (I think) the difference between what a single photon may do and what the average behaviour of a large number of photons will be.
At a specific wavelength, one photon could easily be absorbed after 30m, while a second identical photon could travel 100km. It’s a matter of probabiliitiies. <b<Mean path length of transmission can only be expressed for many photons, and will be related to the probability distribution for individual photons.
Likewise for emissions equations: things like Planck’s Law or the Stefan-Boltzman equation apply to mean properties of many molecules and photons. What happens to individual molecules and photons is a probability function.
And at a slightly different wavelength, the probability distributions, path lengths, etc. will be quite different, because of the need to match energy levels in the molecular structure with energy levels in the photons. That’s why gases on absorb and emit at specific wavelengths. And that’s why detailed radiation calculations are spectral (wavelength specific, and then integrated over all wavelengths) , and include absorption/emission characteristics for all relevant gases.
MarkR: thanks for clarifying the different purposes of the HITRAN and MODTRAN sources.
Bingo, Oil Man:
Thanks!
Hi Izen
You make a really concise and interesting point, your point is about absorption.
Your point for me was great because it helps articulate and solves the puzzle of the “saturation” (or ‘overwhelm’?) of the trace gas CO2 in the atmosphere by incoming IR.
But is has very little to do with how much IR radiation the CO2 emits which is uniquely dependent on the temperature of the CO2?
The point you made relates to the model of CO2 as a sort of IR sink.
It explains why a trace amount of CO2 can absorb lots of incoming IR.
What I have heard is that if CO2 absorbs IR, between the time it absorbs and re-emits, it has about 1000 collisions with other molecules, so 1000 chances to transfer the kinetic energy of the wobbly bond or incoming IR to other molecules, via impetus, spin, whatever.
And I think you could even create an experiment to show this is true.
Irradiate a gas with a trace amount of CO2 in with 15mu microwave IR radiation, and see if the gas heats up? I think it will.
So I agree with you.
And what you are describing is the classic effect of a Microwave oven.
But your point does not relate to the amount of IR emitted?
That is only governed by temperature and density?
Bob
Your reply to me did one of two things. Either you are saying –
1) You are denying that CO2 absorbs IR above 5 km?
You suggest all the CO2 above 5km no longer behaves in a predictable way.
2) You are saying greenhouse gases do what you want them to, when you want the modelling to say IR emitted from 5km no longer gets absorbed by the CO2 above 5km.
I feel rude challenging you like this, but I think that is what you just said by trying to apply quantum randomness to the CO2 above 5 km.
Despite Quantum randomness, (which I entirely agree with on an individual photonic basis), in a statistical sense, millions of CO2 molecules WILL behave in a predictable way and WILL re-absorb the upwelling IR from the CO2 below 5km is from what I understand.
I am just trying to be dispassionate and scientific rather than to prove anything.
I am trying to see what conclusions consistent scientific modelling leads us to?
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and Then There’s Physics
Two sites that have really helped me, I am sure you know them are :
thescienceofdoom.com
Almost every time I’ve come up with some apparent epiphany, those guys have already trodden the ground and set the record straight from a calm scientific point of view.
What this chat with you has done for me is to articulate the problem of the re-absorption of IR emitted from CO2 low (5km) in the atmosphere. For me, there seems a major inconsistency with positing the fact that CO2 is an IR active gas – the whole basis of AGW – then ignoring it above 5km. For me this needs a whole lot more work – and that is what is my takeaway from this discussion.
The density of CO2 above 5km is NOT insignificant, not even to 20km. IR emitted by CO2 around 5km is going to be completely re-absorbed by the CO2 above it is what I am seeing?
So the $64000 question, for me becomes from what height in the atmosphere is IR from CO2 actually emitted to outer space?
Climate Science is furiously difficult, isn’t it?
Anyone that says it is easy is either an absolute genius, or simply doesn’t understand it !
I’ve been wrong lots of times. I don’t think I am on this, and I think I have given reasonable answers to people making points against the idea that CO2 above 5km re-absorbs upwelling IR?
You are clear in that you understand the atmosphere around the earth only absorbs part of the upwelling IR. The upwelling IR ranges from 1 to 100 microns. The IR active gases, H2O and CO2 only operate in a part of this range. Rougly 50% of the IR from the earths surface goes straight out to space.
If you bunch in the radiation from the earths surface with the IR emitted by the CO2, then sure, you will get an EEH point much lower, but that is simply confusing the issues isn’t it? To work out the effect of increasing the EEH by increasing levels of CO2, we have to focus on a simplified modelling which addresses only the IR emitted by the CO2 don’t we? Nothing else has changed, has it? Anyway, that is the way I see it.
Some things I see –
1) CO2 of and by itself in the atmosphere has NIL, ZERO effect on global warming.
Even though earth is blanketed in IR active gasses, this in and of itself means nothing.
What AGW theory is predicated on relies on the lapse-rate to work.
The lapse-rate is driven by gravity.
Clive Best points this out several times, as does the SoD site.
Think, if the atmosphere was a jelly, the whole atmosphere would be at one temperature.
The IR in at the bottom of the jelly would equalize with the IR out at the top.
Nil warming by CO2 by itself.
AGW theory NEEDS the lapse rate to work?
2) Absorption and emission of IR CO2 are not linked
The emission of IR is governed uniquely by temperature and density.
This is the SB law.
The SoD site is great on this.
3) The graphic on the realclimate site you link to in your OP is wrong.
The graph shows temperature increasing with height, doesn’t it?
That suggests to me someone is not thinking clearly
I agree with the EEH model, but, as I said, it has not been bottomed out yet, and needs more work is my view because of the points I’ve made.
4) You gave some really useful and neat graphs of earth’s atmospheric temp with height, plus the power of IR emissions from the earth’s surface.
You claim 225k represents an emission height of circa 5km.
I can actually see at least 3 points on your temperature graph where the atmosphere is 225k,
5km
20km
60km
and I think there is another one if you extrapolate the graph into the Exosphere.
Seems to me this whole notion of 5km is not good or clear thinking?
Anyway, those are some of the points this discussion has brought into focus for me.
And I don’t, at the moment, see anyone picking up or dealing with the problem of the re-absorption of the IR emitted by the CO2 lower in the atmospheric column by the CO2 higher in the column.
And that DOES question the ideas behind AGW, but that is the science or at least the scientific modelling I am seeing ?
This needs attention?
Of course it could all be a bit of cheese I ate, a phantasm, a pointless wild goose chase, but I don’t feel it is?
Peter,
I think this is simply wrong. As MarkR highlighted, the ERF adjusts the radiative forcing to take some of this into account. Also, if you look at ther MODTRAN output I highlighted in an earlier comment, it’s clear that some of the emission is coming from regions where the temperature is ~220K. So, this calculation is taking the emission, and absorption, at higher altitudes into account.
Also, the outgoing spectrum has been measured by satellites and agrees very well with that from MODTRAN. So, the calculation has been done and observations have been made that are entirely consistent with these calculations.
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On a related note, there is an interesting effect in parts of the Antarctic where the greenhouse effect is actually negative (causes cooling). This is largely because of a temperature inversion. The surface is cooler than the lower altitude, so when you add more greenhouse gases to the atmosphere, the emission then comes from a higher altitude that is warmer, rather than cooler. However, it turns out to be slightly more complicated, as this article highlights:
OK thanks for the ERF pointer. I will try and explore.
To be honest not looked yet.
The thing is using the aeronautical atmospheric density tables it looks clear that atmospheric density (kg/m3) at 20km is approx 1/15th of that at sea level.
Planes fly in the Stratosphere; the atmosphere there needs some density to keep them up?
And although this density is low, it seems still more than enough to absorb ALL the upwelling IR?
Could be wrong, I’ll have to figure out the integration equation to model it, but from a cursory fag-packet calc that’s what I am seeing. Maybe the ERF angle will shed some light?
What seems key to me is to focus on the IR emission profile of CO2, since CO2 is the key player. The question I am still left with is where in the whole 100km+ of atmosphere does the CO2 shed IR to outer space? 5km seem a definite no no from where I am sitting. If you don’t see that, or think the question is inconsequential or irrelevant, fine.
Water vapour is fascinating, especially with the dew point some removing H2O.
I have to say I have not got my head around that at all.
I do get a lot of the angles, even the net transfer of heat from the atmosphere to the polar ice due to the temperature inversion. This stuff is so complex it is good to try and bottom out one effect at a time. That is why focussing on the IR flux in the CO2 column seems valid and useful?
And I think even the distribution of CO2 in the upper layers could do with close scrutiny? It is a heavy gaseous molecule, so possibly in higher concentrations at lower heights, mediated by gravity. The Earth has lost Hydrogen from its atmosphere. Saturn and Jupiter have hung on to it because of greater gravity and (I think) the Hydrogen there is found in the upper layers. Lighter molecules seem to orbit higher?
I find the climate so fascinating and complicated it’s almost insanely difficult to model, but of course we have to try and the models are getting more and more sophisticated and fascinating.
I pitched in on this because I felt really happy that I more or less understood and agreed with the EEH effect, which is where you started. Now not so sure!
Anyway, thanks for chatting!
Peter: there is a lot that you are getting confused abut, and you are making interpretations and drawing conclusions that are simply wrong. And you appear to be concluding that those erroneous interpretations are indications that radiative transfer theory and climate science are wrong.
I will take two brief quotes from you latest comments to try to use them as starting points for explanation. Forgive me if you feel that the two quotes ignore a lot of what you say – but I only want to use them as starting points for another attempt at explanation.
At one point, you say “Absorption and emission of IR CO2 are not linked. The emission of IR is governed uniquely by temperature and density. This is the SB law.
I will take the middle sentence first. No, at an individual molecule level, the emission of IR is not defined by temperature and density. An individual molecule of CO2 will have a excess of energy that is needs to shed, and it will do so be emitting a photon. It will shed that energy in a specific amount – the amount contained by that photon, which is a function of wavelength. That photon has that wavelength because that gas (CO2 in our discussion) can only have specific energy levels related to the quantum effects in electron orbits etc. CO2 can only emit photons with energy levels that match those possible shifts within the CO2 molecule.
Absorption of IR is the inverse: the CO2 molecule will only absorb a photon with the correct amount of energy to match the molecular energy state that the molecule is capable of handling. That means the emitted photons are at the same wavelength as the absorbed ones.
Individual absorption or emission events in the same molecule are not linked. CO2 molecules are always colliding with other molecules and transferring energy. A CO2 molecule that has absorbed a photon and thus has higher-than-average energy will almost always lose that energy through collision with other molecules. Periodically, a molecule will gain energy via collisions and shed it by emitting a photon.
Temperature and density are properties of large masses of air molecules, not individual molecules. If a lot of radiation is being absorbed and lost to other molecules (including ones that do not absorb IR), then bulk air temperature will rise. If air is hotter, then it is more likely that individual molecules will end up gaining enough energy to emit a photon. It is in this way – bulk air properties – that you can then estimate bulk average emission or absorption of radiation (Stefan-Boltzman/Planck or Beer-Lambert laws). It is through these bulk properties that you can link the probabilities (not the individual events) of absorption and emission.
In another comment, you say “For me, there seems a major inconsistency with positing the fact that CO2 is an IR active gas – the whole basis of AGW – then ignoring it above 5km.”
Nobody ignores it above 5km. The ideas of effective radiating height, effective radiative temperature, mean path length, etc are attempts to summarize a complex radiative transfer process using a few key statistical values. If you look a the MODTRAN site, you will see that you can as it to give you the upward and downward IR fluxes at any height.
For the upward flux for any wavelength at a selected height (chose 100m, 5km, 20 km – anything you like) you need to remember the following:
1) every single photon of that wavelength is the same – there is no way of knowing if that photon was emitted from the surface, 5m, 100m, or any specific height below the viewing point.
2) It might have travelled 2cm, 2m, or 15km.
3) You have no idea what the temperature was in the atmosphere at the height that photon originated.
4) The probability that an individual photon will be absorbed at the current height has nothing to do with its origins. It has to do with its chances of interacting with a molecule that will absorb it.
The entire vertical profile needs to be integrated as a set of coupled equations. Radiative transfer calculations such as MODTRAN break the atmosphere into layers. For each layer, there will be:
1) A flux arriving from below, of unknown origin. Some of that flux will be absorbed, and some transmitted to the next layer above.
2) A flux arriving from above, of unknown origin. Some of that flux will be absorbed, and some transmitted to the next layer below.
3) An emission of radiation, half of which will be added to the upward-directed flux (1), and half to the downward-directed flux (2).
4) The flux going out the top will be the sum of what arrived from below and was not absorbed, plus the amount emitted upward by the layer.
5) The flux going out the bottom will be the sum of what arrived from above and was not absorbed, plus the amount emitted downward by the layer.
6) Obviously, the amount moving upward out of this layer will be the same as the amount moving upward into the layer above. This is how all layers are coupled together into one system.
When viewed from space, a measured IR flux is of unknown origin. When someone easy “it appears as if it is being emitted from a height of 5km at 255K” they are not saying “it is emitted from a height of 5km at 255K”. To know how much is emitted from what height, you need detailed models and more detailed measurements.
And yes, it has been done.
Peter,
You said that Science of Doom helped you. I just quoted a comment of yours at SOD. It was from an exchange you had a year ago or so where you were Just Asking Questions like you are right now.
Something tells me it did not help you that much if all you could find since then is a contrarian website with a banner saying “Global Warming Not Caused by CO2” and if you keep repeating usual Sky Dragon Cranks talking points about absorption.
In fact the word “absorption” is filtered at Roy’s.
So unless AT has something to add, I suggest we drop the stick and move away from that horse.
“Seems to me this whole notion of 5km is not good or clear thinking?”
It’s a simplification of a textbook model used to introduce concepts. The terms to look up are “kernel function” and “weighting function”. This is included, as standard, in the calculations behind the consensus understanding.
Other useful terms; MODTRAN will give you the “instantaneous radiative forcing” (iRF) for a given profile. Then there are atmospheric “adjustments” to convert that to ERF. Some studies also report the “heating rates” that initially drive those adjustments.
Here’s one paper on adjustments: https://link.springer.com/article/10.1007/s40641-015-0007-5
If anyone is interested, this is Clive Best’s analysis of the EEH as viewed from the thought experiment of incoming IR getting absorbed by CO2 at different altitudes.
Very elegant analysis, much better than my fag packet!
I think I need to study these ideas.
Thanks Mark that looks very useful
Peter: If you’re actually interested you could also pick up a standard textbook on the material…
Global Physical Climatology explains all this quite well.
Its not like any of this is complicated.
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There are also a number of online courses one might take.
And it’s also not at all difficult to write up some code on VPython/Glowscript Tricket ( https://trinket.io/glowscript ) and set up a series of atmospheric layers (slabs, described as a simple function defined between altitudes of z and z’.) I did this, a few years ago, using a different programming language and about a dozen slabs, which seemed well and good enough for my needs to satisfy my own curiosity.
(I specialize, as a matter of the daily work I do, in radiation physics for the purposes of non-contact temperature measurement — which means basically these two areas: pyrometry and phosphor thermometry. So I had a small leg-up, of sorts.)
The 2nd edition of the book you mentioned, dated 2016, provides a good start in chapter 2. If Peter Grimshaw is serious about it, and feels competent to engage the material and master it, then I can also recommend the book. Otherwise, I’m not sure there’s a point to the reference.
Peter will have to work for his own independent, comprehensive opinion. Or else be forced to not have one. But that fact is true for all of us. Not just Peter. We trust the experts or else we are forced to master the material and work towards a comprehensive understanding of the existing knowledge before attempting something of our own. It’s just the way of the world. No escaping it.
Where is the ‘Top of Atmosphere’.
What mass of air is in the earth’s upper atmosphere?
This question is important because air mass, ergo CO2 density, blocks IR from leaving the earth’s atmosphere.
For anyone interested, I think this graph explains one element of the discussion on the EEH.
If the question is where is the Top of Atmosphere? What do we mean?
This is a graph of air pressure against height.
Atmospheric air pressure is a measure of the weight of the molecules above us pressing down on us. At sea level that weight is about 1kg / cm2.
It is important to know the mass of air and CO2 above us , because this tells us how much IR is likely to be absorbed by the atmosphere above us.
This air pressure graph effectively measures the mass of air above any point.
So knowing how much mass of air is above any point helps determine the likelihood of any upwelling IR being absorbed before it escapes into outer space.
And looking at this, I am happy that above about 40km, there is very little mass to speak of.
It is not NIL, and for accurate calculations it would need to be included, but for ‘fag-packet’ calculations, anything above 30-40km can be discounted?
I think this is an important element in explaining how the Greenhouse effect works.
We need to establish at what effective height IR leaves, and cools, earth’s atmosphere.
There are two conflicting thermal gradients at the higher atmospheric reaches.
Tropospheric temperature, to 15km, decreases with height.
Stratospheric temperature to 50km, increases with height.
The effect of increased CO2 molar density in the Troposphere is to create Global Warming.
The effect of increased CO2 molar density in the Stratosphere is to create Global Cooling.
That is why we need to establish the ‘Top of Atmosphere’.
So we can work out the relative proportions of IR that escape from these two different thermal gradients.
That is one issue this discussion has clarified for me.
Trying to make sense of what the EEH means in physical-mechanical terms, which I think is very tricky to bring into focus, is where this thread started, and this is one important element.
What is meant by ‘Top of Atmosphere’?
http://olevelphysicsblog.blogspot.com/2010/08/gas-pressure.html
Peter,
Again, I think you misunderstand what is typically mean by the Top of the atmosphere in this context. There isn’t really a single layer that is the top of the atmosphere. It’s really just means that we’re considering fluxes that represent energy inputs, and outputs, to the whole system, rather than just energy fluxes at the surface. You can, of course, consider a layer that is pretty high up in the atmosphere so that there little is little influence from regions above this. If you don’t like the term “top of the atmosphere” you could call it something else, although I can’t think of a better term.
I don’t understand how we are far apart on this.
The EEH to my mind is a Top of Atmosphere effect.
And yes of course that is a series of layers, that is the integration – how much escapes from each later. And of course top layers, which have no other layers above them emit more IR to outer space, and layers lower in the atmosphere emit less IR to outer space because there are more layers above them to navigate through?
And yes add to that the complication that higher layers are less dense.
I’m actually really comfortable with this molecular mechanism for describing the EEH.
Emissions reduce as temperature reduces?
A lower gaseous temperature means the molecules have less energy and stop emitting so much IR doesn’t it? – But they can still absorb the same amount?
To me it also potentially explains the overall warming of the earth’s atmosphere by the CO2 blanket.
The upper layers of the troposphere are much cooler than the sea-level layers.
This effectively strangulates the emission of IR from the cooler, higher layers of CO2 even though the sea-level layers have absorbed more than is emitted from the higher, cooler layers.
The higher layers are not emitting as much as the the lower layers are absorbing because they are cooler and less energetic, so the equilibrium state will be just that and the ‘blocked’ heat needs to escape probably by a back-heat of the surface which then emits in a different spectrum.
If I was trying to explain the EEH to a skeptic, I would not talk about water vapour at all.
And I would not mention the 5k idea at all.
The 5km idea simply conflates a bunch of radiative effects and obscures the CO2 mechanism that is happening?
To my mind is the EEH is 100% an effect of the temperature of the CO2 at the range we call the Top of Atmosphere – the area that most of the IR escapes to outer space from and cools the atmosphere.
I think another confusion is no actual “flux” of IR through the earth’s gaseous atmosphere.
I found this really difficult to grasp, and it was the SoD site which explained this so well.
The atmosphere is not like wire that electricity “flows” through?
There is no ‘flow’.
There are two completely separate and unrelated things, absorption and emission.
As Izen pointed out, CO2 is capable of absorbing loads of IR.
Then there is emission, which is more or less temperature dependent.
The two are not linked at all? That is tricky to accept or grasp.
If the CO2 was at 0K, it would still absorb loads of IR, but would emit none.
There would be nil ‘flow’ or ‘flux’ through 0K CO2 if one side was hot and the other was cool.
It is only when the CO2 heats up it then it starts emitting.
Emission of IR are almost wholly described by S-B and are temperature dependent?
On the other hand put a potential difference across a super-cooled wire and you will get a flow?
There is no ‘flow’ or ‘flux’ of IR through the atmosphere like electricity, there is only absorption or emission and emission is temperature dependent.
Sure, it appears like there is a flow because not all the IR emitted from a point is absorbed by the layer above it, and some goes through the first layer, but eventually, most (or 99%) of the IR emitted from given a point will be absorbed by the layers of CO2 above and around it if there are enough layers. And of course, near the Top of Atmosphere (TOA) there are NOT enough layers to absorb all the emitted IR from layers near the TOA, so the topmost layers start to emit IR to outer space?
And that is the beauty, weirdness, and principle of the EEH in action to my mind.
IR emitted from CO2 in lower layers is eventually soaked up by the layers of CO2 above it.
And that is the mechanism that drives the effective height of emission upwards as the CO2 gets denser? And mostly, in the Troposphere at least, increasing height means lower gaseous temperature
And sure, the uppermost layers are in the Stratosphere, and that has the opposite effect, but from the atmospheric pressure graph we can see that the upper atmosphere is pretty thin, not much mass there, and actually vanishes round about 35km.
If you look at Clive Best’s graphical analysis, he has the 15mu band of radiation coming from the Stratosphere, but everything around it coming from the Troposphere.
To be honest, I can’t keep up with everything Clive has written, Clive is furiously clever and has worked at CERN, but overall, Clive is saying the EEH causes global warming.
The EEH is primarily a Top of Atmosphere phenomenon caused by the interplay between CO2 and the lapse-rate, but not by CO2 on it’s own? CO2 without at lapse rate has nil effect?
Anyway, that is my pennyworth!
I am fairly comfortable I have a good grasp of that, if you don’t, you don’t that is fine too.
And despite what anyone says, I think this is super-complicated, which is one of the difficulties of explaining it to the general public ?
Peter,
But the reason that it’s useful to mention 5km is that the Earth radiates, in space, the same amount of energy per square meter per second as a 255K blackbody and 255K is roughly the typical temperature in the atmosphere at 5km. It’s overly simplistic, as I think MarkR mentioned, but it’s still a useful approximation.
I think this is wrong, as Bob was pointing out. At an individual molecule level, the molecules absorb and emit, or lose, energy (either through absorbing and emitting photons, or through collisions with other molecules). If there is a region that is sufficiently dense, then the overall emission from all the molecules becomes temperature dependent, but this isn’t true for an individual molecule.
I’m not sure how CO2 would behave at 0K, but if it absorbed some photons, it would no longer be at 0K.
I think your overall understanding of the absorption and emission of photons is wrong. A molecule that absorbs photons, will – fairly quickly – emit that photon (unless it loses that energy through collisions). It’s not correct to think in terms of there being a layer in which the molecules absorb lots of photons without releasing that energy. So, if the upper regions of the atmosphere emits inefficiently (or emits very little energy) then it will also be a region that absorbs very little energy (optically thin).
[Enough, Peter. You’re not listening, and you keep lecturing on something you obviously have not studied. Find yourself an online course. -W]
In your post you state:
“However, the shortwave feedback (mostly due to changes in clouds) leads to an increase in absorbed solar radiation, which causes the system to keep warming, increasing the outgoing longwave flux to above the level it had before the greenhouse gas concentrations increased.”
OK- But how and why does increased CO2 reduce cloud cover?? And are we sure it does and will continue to do so??
This scientific question have been repeatedly discussed witjhout clear answers, and even in IPCC-reports the question of changes in cloud cover.
For instance in IPCC4 it was stated;
” In many climate models, details in the representation of clouds can substantially affect the model estimates of cloud feedback and climate sensitivity (e.g., Senior and Mitchell, 1993; Le Treut et al., 1994; Yao and Del Genio, 2002; Zhang, 2004; Stainforth et al., 2005; Yokohata et al., 2005). Moreover, the spread of climate sensitivity estimates among current models arises primarily from inter-model differences in cloud feedbacks (Colman, 2003a; Soden and Held, 2006; Webb et al., 2006; Section 8.6.2, Figure 8.14). Therefore, cloud feedbacks remain the largest source of uncertainty in climate sensitivity estimates.” https://archive.ipcc.ch/publications_and_data/ar4/wg1/en/ch8s8-6-3-2.html
The research here is far from settled, as you can see in this report from 2020 from the EU commsion, where the headline reades;” They might be beautiful at times, but clouds are still one of the biggest sources of uncertainty in understanding how the climate will change due to global warming, explains Professor Pier Siebesma, an atmospheric physicist at Delft University of Technology (TU Delft) in the Netherlands.”
https://ec.europa.eu/research-and-innovation/en/horizon-magazine/qa-why-clouds-are-still-one-biggest-uncertainties-climate-change
Tor,
Firstly, the main point of this post is to highlight that increasing absorbed solar radiation doesn’t somehow challenge the basics of the enhanced greenhouse effect. Also, it’s hardly a surprise that change the temperature in the atmosphere has an impact on clouds.
You’re correct, though, that one of the greatest uncertainties is indeed how clouds will respond to global warming. However, there is no observational evidence to suggest that clouds will slow down global warming. The best estimates today are that the cloud feedback is positive, even if it is still rather uncertain.
Thank you so much, for thequick response and comment!
I completely agree that there is no evidence to suggest that clouds will slow global warming. However, the physics regarding reduced cloud cover and albedo changes is different from the classical physics of “Forcing by greenhouse gases”, https://www.epa.gov/climate-indicators/climate-change-indicators-climate-forcing
Similar, the formula of RF = 5.35 ln(CO2/CO2_orig) cannot tell us much about changes in cloud cover or inrease in ASR, and if increase in ASR will be the main driver of global warming in the coming decades, than the warming will be difficult to predict.
Therefore, for example the estimates of how much CO2 we can emit before exceeding 2 degrees increase in global temperature seem based on physics that focus on reduced OLR, not increased ASR, so how relevant are they?
Tor,
No, these estimates comes from many sources, incuding models that include forcings and feedbacks. Hence, these models include the cloud feedback and that we expect there to be an increase in ASR. In fact, one of the reasons for the large uncertainty in climate sensitivity is because of the large uncertainty in the cloud feedback. So, the detailed physics does not focus only on reduce OLR.
Tor,
Here is a bait:
[BAIT] I completely agree that there is no evidence to suggest that clouds will slow global warming.
Here is a switch:
[SWITCH] However […]
The topic of the thread is the Greenhouse Effect, not luckwarm issues with sensitivity.
For more on the luckwarm brand:
http://rabett.blogspot.com/2015/09/eli-explains-it-all.html
Notice the date.
“dumping giga-tonnes of CO2 into the atmosphere”
Haven’t we been doing that for ten millennia by feeding ourselves? Taken carbon from the soil to the point that makes contributions from fossil fuel use almost insignificant?
Hal,
No, that was largely carbon neutral. When we fed ourselves, we also then regrew food the next year that took up the carbon we’d emitted. The problem now is that we are emitting carbon that has been sequestered for thousands of years as fossils, and we’re emitting it much faster than the rate at which it can be sequestered back into the lithosphere. It will eventually be drawn down again, but this will take something like 100000 years.
It’s funny. When I first wrote a short note about Rasool & Schneider 1971, I wrote up a second one (which I threw away as perhaps pretentious.) You’d written, “…adding more greenhouse gases to the atmosphere increases the altitude at which energy is radiated to space…” and that immediately brought me back to many of my hours wasted on web-arguments because of individuals (intentionally, as I later concluded) making these kinds of “confused” arguments I now watch playing out here with Peter.
I had wanted to warn you that you may need to expand and/or modify how you wrote in order to anticipate and deflect some of what I saw coming down the pike.
I’ve been in a similar place, having written less at first and regretted how it was intentionally mangled by those moving towards their desired end-point in the discussion. I am too tired to care anymore, or at least nearly as much as I once did. Either they put in the time and show me specific quantitative details they are struggling over, so that I can help correct their mistakes or admit my own, or else they can just “go away.” But if they cannot be bothered to work for their opinion, then neither can I be bothered to try and help out.
That experience I went through (on this very topic) burned me a bit, I suppose. It did lead me to come up with the phrase (that speaks perhaps a little more to an American audience)
“An equal right to an opinion isn’t a right to an equal opinion.”
I needed something short and memorable. And that’s the best I could do at the time. It did also help me put that experience into a box that I could leave on a shelf and no longer worry about.
ATTP:
Someone using the name Hal Kantrud has been flogging that same horse off and on for a year and a half over at SkS.
Jon,
I do try to anticipate this, but I don’t always manage to work out all the ways in which what I’ve written could be mis/over-interpreted.
Bob,
Thanks.
That’s a truth for all of us!
Another small mental “resonance” now comes unbidden to mind. This one from the following paper, https://www.stroustrup.com/oopsla.pdf , where Dr. Stroustrup writes:
There is never enough time, even in the best of circumstances. And certainly not on topics as subject to intense, and far too often intentional, abuse as climate.
And so we muddle along, having to re-trace over old lessons as we each find our own way.
Can anyone explain how a possible cloud negative feedback could reverse and cancel a warming trend when that warming is required to cause the change in cloud cover ?
I can understand how it COULD reduce sensitivity, however there would seem to be a limit on how much by the variation in seasonal climate.
Not to mention the variations seen in longer historical/millennial changes.
I wonder how many giga-tonnes of CO2 humans dumped in the atmosphere 10K years ago:
https://en.wikipedia.org/wiki/World_population
We’re a bit more than that nowadays.
Besides the fact that, as AT observed, most of this activity was carbon neutral before the arrival of fossil fuels, there’s a big speed difference between 10K years and 100 years.
***
A related argument is being promoted by fans of Ed Berry at Roy’s, e.g.:
https://www.drroyspencer.com/2022/04/explaining-mauna-loa-co2-increases-with-anthropogenic-and-natural-influences/#comment-1239858
The overall argument goes like this:
(P1) To be sure that the extra CO2 in the current atmosphere is man-made, we’d need to be able to distinguish its origin.
(P2) CO2 is CO2, and we can’t distinguish where it’s from.
(C) The IPCC’s conclusion is premised on an erroneous model.
The best refutation I know is from NG:
http://climatechangenationalforum.org/your-logic-escapes-me-by-john-nielsen-gammon/
The same argument also destroys Roy’s 50-50 argument.
A good argument ought to be able to kill more than one bird at the same time.
In a sense global warming itself is the principle evidence supporting Svante Arrhenius’ 1890’s claim that burning fossil fuels would raise global temperatures. The experiment was already underway in his time, albeit at small scale. Welcome to the test tube. It may not be perfect but I’d much prefer computer modeling.
Of course I know it isn’t as simple as just CO2; the climate does keep changing – the “but the climate is always changing” sort as well as anthropogenic – and each influence down to the least needs quantification, just to be sure, and to narrow the uncertainties – even whilst knowing full well that GHG’s and aerosols obviously have changed and there are clear physical bases for the expected effects, which are occurring in amounts that are consistent with them, that add and subtract about right.
Hal Kantrud,
The impact of industrialisation on atmospheric Co2 is crystal clear:
James Watt’s first patent was published 1769.
I stayed out when it became obvious that someone was Just Asking Questions.
But I have to comment on the hilarity of the reversal of the old denier trope “but CO2 is plant food”.
Priceless!
meant to add, that graph’s a little out of date, we’re at ~420ppm now
Is Roy still getting confused by regressions and derivatives? I pointed out the risks fully a decade ago in my blog post at SkS Roy’s Risky Regression. He ought to know about this as I emailed him a copy for comment before it was published (I didn’t get a response).
Be interesting to know how a 15% natural contribution is consistent with the natural carbon cycle being a net sink.
Oops, looks like I messed up the tags as usual, the blog post is here:
https://skepticalscience.com/roys_risky_regression.html
Roy is being Roy:
https://www.drroyspencer.com/2022/04/explaining-mauna-loa-co2-increases-with-anthropogenic-and-natural-influences/
Different argument. Same endgame.
I had a quick look and I think it still contains a lot of the of the same components
The problem here is that the long term growth of atmospheric CO2 depends on the average value of the year-on-year change in CO2, and correlation is completely insensitive to that. So there is no mathematical link between that correlation and the long term rise in CO2.
Or the mass balance analysis which shows the natural environment is a net sink and hence is opposing the rise, rather than causing it. Roy knows that there is evidence that contradicts him, he said so in a previous post
https://www.drroyspencer.com/2014/08/how-much-of-atmospheric-co2-increase-is-natural/
I did follow his link to the Wikipedia article on Master Equation
https://en.wikipedia.org/wiki/Master_equation
Which doesn’t immediately sound like an appropriate tool for analysing the carbon cycle.
Of course none of the audience will conclude that climate scientists have made an obvious error in the attribution of the rise in CO2, that caveat buried in the middle of the post should ensure that!
Yay, Roy has discovered the mass balance equation (sort of). You don’t need a regression here, an equality will suffive
dC02/dt = Anthro(t) + Natural(t)
We know that dC02/dt – Anthro(t) is negative (we can observe it) and that tells us that Natural(t) is also negative. Hence it is opposing the rise. Salby found the same equation as well without spotting the obvious corollary.
This is exactly the same mistake he made in 2009. The “linear trend” *IS* the long term rise, so if you get rid of that, you can say nothing about the cause of the long term rise via correlation analysis.
It’s my birthday, I will have too few birthdays after this one to spend any more time on the carbon cycle canards.
Sorry if I have messed up the tags again, I will have checked them again before pushing the “Post Comment” button.
BTW Jon, liked the nice Stroustrup quote, not a source I’d expect to see quoted here ;o)
Happy birthday, Dikran!
Happy Birthday, Dikran.
Thanks Willard and ATTP, a DM song I didn’t know, enjoying the silence might help get the balance right ;o)
About 15 years ago, the details of an error in the post processing used to generate the UAH MSU T2LT results were demonstrated here:
Click to access 104116.pdf
Now, no one likes replicating the results of others. If all you do is show that it replicates, you’ve not added a thing but you’ve wasted a lot of important time and mental creativity in your life for nothing much. And if you show something is wrong, you very often have done little of creative importance because everyone is moving on, anyway. Just as Rasool & Schneider’s 1971 paper was very soon eclipsed by work in the next few years. What pays is doing your own research. Especially if you find a positive result that is published in a higher tier publication.
But the UAH MSU T2LT dataset was the only dataset at the time that conflicted with other approaches, others which uniformly showed warming trends. This conflict continued for years. Dr. Spencer and Dr. Christy were repeatedly asked to check their methods to see if they could come up why their results uniquely differed.
Finally, Dr. Mears and Dr. Wentz set aside other work and dived into the methods of Dr. Spencer and Dr. Christy, themselves. Eventually (and it was quite a pregnant pause, as I recall), Dr Spencer and Dr. Christy did go back through their dataset and make some corrections and, while the warming trend did show up, it was still lower than with the other datasets. But at least more consistent with them.
Each of us suffer from limited perspectives and worldviews coloring how we perceive. We also try to develop personal tools. associations, and ongoing discussions with others in an attempt to counter the ease with which we may deceive ourselves (we can fool ourselves so much easier than we can fool others.)
But their results were such an outlier. When I finally got a chance to read the paper by Dr. Mears and Dr. Wentz, I just kind of blew up and started digging, finding a few clues (my colored glasses operating here.)
Dr. John Christy served as pastor of an evangelical Baptist church and later went to Kenya as a missionary before he took up his mathematical career. That career led to his working for UAH/NASA MSFC.
A story in the NY Times quotes John Christy:
Dr. Spencer also used to maintain this site:
http://www.techcentralstation.com/080805I.html
But it is gone. You can find it with the wayback machine here:
http://web.archive.org/web/20050811024427/http://www.techcentralstation.com/080805I.html
It’s titled “Faith-Based Evolution”.
I also had never (at the time) heard of the Cornwall Alliance. Turns out they are Evangelical Christians of the Dominionist variety. (To me? A pretty scary group, then quite well-funded; though now I’ve no idea about its current state of affairs.)
Dr. Spencer appears in one of their videos at about 7 1/2 minutes into this video:
And I calmed down. Things made sense and I stopped lumping it to disingenuousness. They’d simply fooled themselves. That can happen to any of us. I just think they are a little more stubborn about it than some and perhaps less responsive to criticism than they should have been.
Their work should continue to be judged on its merits, of course. The above notwithstanding.
There is great joy at the Cornwall Alliance, for the Heartland Institute brethren have just published an 81 page climate textbook for homeschoolers by famed educators Anthony Watts and James Taylor.
I can hardly wait to review Climate at a Glance for teachers and students, which Amazon assures me will arrive today. I have no qualms about buying it , as WUWT provides more than $9.99 worth of slapstick entertainment on a daily basis.
From what I’ve seen , it may deserve to be more widely reviewed by adults that read by children.
Jon,
Thanks, some interesting background. I was aware of the Cornwall Alliance. In fact, I think Roy Spencer signeed the Evangelical Declaration on Global Warming, which explicitly says:
So, it seems that he has explicitly acknowledged that his religious views influence his views on global warming. It’s honest, I guess, but would seem to suggest that he’s not likely to be easily swayed by other evidence.
ATTP
John Christy is equally devout, and as Cornwall and the Heartland Institute, are firmly allied, evangelical home schoolers seem to be the target audience for their latest climate tract:
https://vvattsupwiththat.blogspot.com/2022/04/ask-heartland-for-review-copy-today.html
I call art:
https://www.drroyspencer.com/2022/04/explaining-mauna-loa-co2-increases-with-anthropogenic-and-natural-influences/#comment-1260238
Check the “realistic e-times”:
The “model” is here:
https://www.dropbox.com/s/f8i39w6t3gl35rn/220424.xlsx?dl=0
Willard, I’ve learned over time to stay increasingly clear of any debates about atmospheric CO2 and especially “spreadsheets.” If I were to be tempted today, I’d first master materials such as this one, sufficient to lodge additional criticisms or useful thoughts they may have missed:
Click to access bg-16-1505-2019.pdf
If I felt I understood global, synoptic, and mesoscale changes on seasonal and daily time scales, and understood what we know and why we know it about each and especially have identified what’s left over as unexplained residuals for each, I might engage. Only then, after I also spent some time discussing what I think I’d gathered up with those with relevant published papers and making sure I had the details fully grasped. Because then I could literally crush any opposition in short order and let nothing escape my gaze. But without that mastery, I’d be too ignorant and too likely to provide a crack into which some of my opposition would then insert a crowbar. It would truly only be a strawman crowbar, as my ignorance has nothing to do with the state of science knowledge on a topic. It’s only about me. But to my opposition it would seem a victory against scientists (who are innocent of my behaviors and failings and yet may have to bear the brunt of it all the same in the eyes of those I debated.)
Most of us are just hobbyists. We can argue with each other. But the serious work is happening elsewhere. Unless I find the time, and find others willing to give theirs to me as well, I’m staying out of debating quantities.
I tend to see two turfs. There’s the turf for scientific debate (knowosphere), where I’m not qualified to participate. And there’s the rough-and-tumble, wet-T-shirt, mud-wrestling that happens amongst the otherwise ignorant hoi polloi (the rest of us who lack a comprehensive view.) The latter is what I consider to be the propagandasphere — the place where anyone with an axe to grind, a horse to flog, or with money to be made shows up and nothing serious is ever resolved but people still feel obliged to engage. (“An equal right to an opinion (propagandasphere) isn’t a right to an equal opinion (knowosphere).”. Just different places to be.)
Sadly, any time a scientist decides to engage in the climate propagandasphere and try to clean things up in that mud-pit, all that really happens is they get all covered in mud. So I understand those that just stay out. Why try? But I also have a lot of respect for those scientists who feel able to reach out and attempt to lift others willing to learn, too. Outreach is important. It’s a complicated decision for scientists. I’ve kind of given up wrestling in the mud but also know I’m not qualified for much else, either. So I know a few things. But mostly not so much. And I only hope to gain a few more interesting ideas before I die and take it all with me.
To each their own, Jon.
No need to worry – I don’t think I ever lost time trying to convince contrarians. It’s more a matter of persuasion for me. The best way to test my lines is to offer them to those who have no other choice but to respond to them. As soon as they rely on cheap shots, they lost, for style matters.
There is some merit in what contrarians do. If we could tap into it, the world would be a better place. One day hammering on their keyboards might power grids in Africa.
I expect more than that. I expect contrarians to contribute. For that they need to learn to become constructive. That’s the hard part. So many personality issues. But scientists are humans too. No need to turn contrarians into saints to make them help improve our scientific outlook.
My path isn’t for everyone. It might not be for me either. Not for long, that is. Not as intensively as it has been. Other passions await.
While awaiting delivery of Watts new book, I discovered that it isn’t: its’a new edition of the Heartland Climate Realism Project tract of the same name,:
Which you can read online without being suckered out of $9.99 at:
https://climateataglance.com
Willard: Thanks as always for the snip snip. 🙂
Dikran: Depeche Mode is apparently getting together for another album. Personally I prefer their more aggressive stuff played loudly. (I notice that with a PHEV, I don’t have to play it as loud, so there’s that.)
Russellseitz: There’s no point in hiding propaganda behind a pay wall. Ever notice that denial papers are free to see but real science, actual boring science, is hidden in behind pay per view journals? It makes you wonder how they make money selling propaganda doesn’t it? COD?
We all are somewhere on our own varying line of progress. My current point of progress may be here while yours is along some different line and there. I’ve no problem with that difference in place and time. We are each at different places in different times.
I’m just done with arguing with those unwilling to put any of my time towards others who aren’t seriously pursuing their own more comprehensive views. I don’t mind working shoulder to shoulder with other serious hobbyists to gain some foothold, here or there. I’ve just given up on the idea of arguing, much, with those who don’t show good evidence of working as hard as I am.
That is where I’m at in my own progress, anyway.
[Mod: I think this might be called “playing the REF”.]
More like ‘playing the game.’ Is that the new definition of Climateball? Only one side gets to play?
Tom,
You know what “playing the REF” means in this context. Let’s not do this.
@anoilman I’ll look out for that! I’m more a Berlin School man myself, but I’m not bigoted about it ;o)
@Jon on this particular topic, I did the ground work to to make a minor contribution on this particular question,
Gavin C. Cawley, On the atmospheric residence time of anthropogenically sourced carbon dioxide, Energy & Fuels, volume 25, number 11, pages 5503–5513, September 2011.
https://pubs.acs.org/doi/10.1021/ef200914u
non-paywall pre-print here: http://theoval.cmp.uea.ac.uk/publications/pdf/ef2011a.pdf
For this particular question, a fairly simple model covers all basic issues (short residence time, longer adjustment time, only a small fraction of CO2 is of directly anthropogenic origin (duh!), the excess of CO2 however *is* anthropogenic, the constant airborne fraction is due to driving a first order dominant process with an exponential perturbation). Hopefully the paper is reasonably accessible, in 10 years I don’t think it has changed the mind of anybody that argued the rise in CO2 was natural.
It contains a model similar to the one Willard seems to be discussing. Perhaps I should implement it in Python and put it online as a Jypyter notebook…
I’ll read through it when I get a moment. It appears to be addressing another paper’s conclusions. So I’ll have to get access to that paper, as well, in order to more fully apprehend the limits and scope of what it is about. The paper seems simple enough, skimming quickly, with math that I’m quite comfortable with. I’m still not going to engage in wet-T-shirt contests, anymore, though. I’m kind of done with that. But I’m always interested in learning to see how others see. So I’d like to read through the paper(s) when I’ve the time and inclination to give it a fair reading.
There’s also a couple of nice sites for Python code that I’ve used before:
https://www.glowscript.org/
https://trinket.io/
It could run in a browser.
Somewhat relatedly, PP’s recent comment on a previous post made me find this:
https://romps.berkeley.edu/papers/pubs-2020-logarithmic.html
Not exactly the “engineer-level formal derivation” the Auditor once requested, but the talk is nice.
The thread at Elon’s might be clearer:
Dikran: You’ll be saddened to hear that Nena died. She was carried away by 99 red balloons while preparing to appear on The Grand Tour.
https://thegrandtour.fandom.com/wiki/Nena
Willard,
Thanks. I found that when I was writing the post about David Romps’ debate with Steve Koonin. It seems like a nice explanation, but I’m not sure why he suggests it doesn’t depend on the tropospheric lapse rate when his own analogy seems to be suggesting that as you add COS, you push wavenumbers higher up the lapse.
@anoilman you had me worried for a moment there!
dikranmarsupial
“April 26, 2022 at 5:56 pm Be interesting to know how a 15% natural contribution is consistent with the natural carbon cycle being a net sink.”
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Happy birthday by the way
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Can you explain to me if this guy is right or not.
Or even legitimate.
“Water Vapor Myths A Brief Tutorial(copyright 1998-2020)
Author: Steven M. Babin, MD, PhD”
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The premise is that the CO2 levels in the atmosphere are totally dependent on the partial pressure of CO2 from the ocean.
Which in turn could imply that the ocean is a gigantic buffer.
Hence any temporary excess of CO2 production, ie the 15% natural contribution is just absorbed into the sea and neutralized.
The CO2 in the atmosphere would then be purely a result of Global surface temperature on ocean and other waters exposed to the atmosphere.
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Of course this should not be right?
angech,
It’s not right because it ignores the Revelle factor, which I discuss in this post. Yes, the ocean does act as a buffer, but it turns out that if you work through the carbonate chemistry of seawater that there this relationship that is referred to as the Revelle factor. Essentially it is the ratio of the fractional increase in the partial pressure of CO2 (which essentially tells you the atmospheric CO2 concentration) and the fractional increase in Dissolved Inorganice Carbon (DIC). The Revelle factor is typically about 10, which means that if we increase the DIC by 1%, the partial pressure of CO2 increases by 10%.
So, if we add extra CO2 to the system (which increases the DIC) we will indeed increase atmospheric CO2 concentrations and this will persist for a very long time (until it is drawn down through much slower processes). Also, this relationship means that once ocean invasion is complete (all the CO2 that can be dissolved in the ocean has been dissolved in the ocean) about 20 – 30% of what we’ve emitted will remain in the atmosphere. This is one reason for the expectation that stabilising warming will require getting CO2 emissions to zero, because once we’ve done so atmospheric CO2 concentrations will initially drop, but will then stabilise when the increase in atmospheric CO2 is equivalent to about 20-30% of cumulative CO2 emissions.
This initial drop in atmospheric CO2 will essentially balance out the expected warming to equilibrium that would have occured had atmospheric CO2 concentrations remained fixed, but means that global average temperature will stabilise and not reverse once we get anthropogenic CO2 emissions to (net) zero.
FWIW angech’s source makes no such claim, it doesn’t even seem to mention CO2.
That paper by Steven Babin is useful to understand the physics. My own experiential yardstick is in controlling molecular beams in a ultra-high vacuum setting. Chunks of elemental arsenic start to outgas at a relatively low temperature and with a calibrated mass spectrometer its straightforward to monitor partial pressures from 10e-11 to 10e-4 Torr. The only thing that matters is the temperature of the hottest emitting surface. All the arsenic molecules will eventually stick to lower temperature chamber surfaces, but will also create a residual pressure background once the source furnace is turned down. So to get the arsenic off the chamber walls, have to wrap the whole system in a thermal blanket and have the cryogenic pumps trap the molecules bouncing around the cavity. That’s the only way to get rid of them above the residual background.
The analogy to the climate system is direct. The CO2 molecules are like As4 molecules and will hang around in a residual state as long as there is no permanent trapping/sequestering state for them to go to. The issue is that all we are doing is adjusting the emitting surfaces a few degrees at most and dealing with the repercussions of pumping all that anthropogenic CO2 into the atmosphere. We see all the short term cycling of CO2 in the readings from seasonal + ENSO temperature cycles but don’t have a cryogenic pump available to trap the excess. Dry ice is -78C and the poles don’t get that cold. The ocean is of no help as the CO2 gets absorbed and does a random walk before getting kicked back out of the atmosphere, thus only holding about 50% of the net at any one time.
the rare molecular beam epitaxy lab configuration at IBM :
@Dikran,
That is one seriously confused article.
The ramble on the semantics of saturation definition reminds me of “skeptics” who apply electrical engineering definitions of positive feedback to climate and loudly proclaim that climate science is bunk as a result.
This rather reads as though the author thinks the visible “steam” coming out of a kettle is water vapor, when of course it’s not. The water vapor is the invisible bit so close to the spout you’d scald your eyes looking for it. It only becomes visible when it condenses to aerosols and droplets in the cold air, when of course it becomes liquid water, not water vapor.
You’d normally say “mixed”, not “dissolved” though. We do talk in geology about things like CO2-H2O solutions, but at the P,T conditions of interest pretty much everything is supercritical not gaseous.
But then I suppose you can get an MD while knowing little or nothing about physics. And since I can’t see how you get onto a physics graduate programme without an undergraduate degree in physics (or perhaps something transferable like maths and astronomy, especially if the physics was in the astrophysics field), I presume his PhD is equally irrelevant to the topic in hand.
Dave,
Yes, I’ve come across that pedantry before. Technically correct, but most people know what is meant by “warmer air holds more water vapour”.
VTG “That is one seriously confused article.”
not nearly confused enough though to be suggesting that “CO2 levels in the atmosphere are totally dependent on the partial pressure of CO2 from the ocean. ;o)
DG “But then I suppose you can get an MD… “
to be fair, I think he is a physicist of some kind with an MD, his first degree is in “Engineering Physics” and his PhD is in metrology (www)
Ah yes.
So to be pedantically consistent ATTP, I should really talk about unmixing not precipitation 🙂 .
As we do in geology with, for example, the unmixing on cooling from high temperatures (in the order of 700°C) of a single-phase alkali feldspar into antiperthite (lamellae of plagioclase and orthoclase feldspar within a single crystal). Or for the more space-minded, Widmanstätten structure in meteorites.
Cool! That got me digging into my PhD thesis for my antiperthite-bearing partial-melt migmatite. And led to a Eureka! moment. I had two independent P,T estimates for the melt, one less than 500MPa, the other 700MPa, both around 700°C. The antiperthite fitted better with the lower pressure, because you have a nice wide light blue zone and don’t have to appeal to a very special Goldilocks composition to go from single-Fs to two-Fs. But it was too low-pressure to fit with my matrix (post-crystallisation) pressures of around 700MPa, which were based on multiple independent lines of evidence.
Subsequent work involving resolutions and techniques not available in the late 70s has shown that there were two closely-spaced metamorphic events, one low-P, high-T associated with rifting and gabbro intrusion, the second compressional and high-P, high-T. I was trying to reconcile the two into one event. We now know the rocks followed an anticlockwise P,T path from my low-P, high-T, through my high-P, high-T to my matrix high-P, intermediate-T. Compression and thickening followed so swiftly that there was still residual heat from the rifting. That’s actually not uncommon in modern settings like the Western Pacific or the Mediterranean.
I knew that already but had never before tied it to the that problem rock from four decades ago. Every day a schoolday!
Well, if the engineers can throw in engineering analogues…
It often takes a highly controlled experimental apparatus to reveal the secrets of vaporization. If you Google Scholar “layer-by-layer evaporation”, at the top of the hits you’ll find our paper on the wildest discovery ever IMO. Take a perfectly flat (i.e. singular) crystalline surface and start heating it in an ultrahigh vacuum chamber — you might expect that the surface adatoms might peel off randomly, perhaps developing pits. But in fact they often peel off in a layer-by-layer fashion. I was in the lab when we were monitoring the photometer output on the plotter and it blew our mind when it started oscillating.
https://scholar.google.com/scholar?q=%22layer-by-layer+evaporation%22
BTW, we beat the team at the Electrotechical Laboratory (the Bell Labs of Japan) by a hare on this discovery. They referred to it as “layer-by-layer sublimation”, which is more technically correct by a hare.
The connection of this experiment to a GHG surface effect is apropos. Occasionally someone will bring up the claim that infrared radiation entering the ocean surface adlayer will not heat the subsurface volume, thus explaining why excess CO2 will not lead to ocean warming. This is rationalized by the idea that IR photons are quickly absorbed by water (IIRC within a few microns of the surface) The outcome of this is that the photon energy absorbed by the surface will not go into heating the subsurface but instead will result in vaporizing the H2O. That’s because water is not the best thermal conductor.
It’s easy to do the experiment (which I did several years ago). Take a pan of water with a thermometer over it and try heating it with an overhead infrared lamp. After several days, you will observe that the temperature has not risen. … BUT, if you slightly vibrate the pan while shining the IR, it will heat up! Now, consider that the ocean is constantly roiling with a vertical eddy diffusivity of 1 cm^2/second (equivalent to the thermal conductivity of copper) and you can see how the anti-GHG skin effect claim is plausible but straightforwardly debunked in practical terms. Read more about this at a RealClimate post from 2006 called “Why greenhouse gases heat the ocean”.
Hare, ha ha, must have had Eli the Bunny on my mind
I’ve always like the Mars aerogel analogy: Enabling Martian habitability with silica aerogel via the solid-state greenhouse effect.
Think of the translucent, low-thermal-conductivity material as the troposphere, up to the radiating level where it becomes optically transparent to IR. Then apply the First Law of Thermodynamics. Energy out = energy in. The temperature at the top of the aerogel is fixed. It has to be so that IR emission matches solar irradiance. The temperature gradient in the aerogel is set by the thermal conductivity of the material. Because it’s a solid it can’t convect. In the atmosphere the temperature gradient is set by the lapse rate, but for the concentration and temperature changes of interest that won’t change enough to matter.
The surface temperature is simply calculated from the radiating temperature at the top of the aerogel, the thickness of the aerogel, and its thermal conductivity. Simple arithmetic. Adding more CO2 means you have to wait for thinner, i.e. higher atmosphere until it gets optically thin enough to let IR out. In the aerogel analogue, you’ve made the aerogel thicker but the temperature at the top stays the same. Ergo, the temperature at the bottom rises. The rest is just detail.
Pukite’s most recent contribution provides yet another nuance justifying my comments on April 27th, about not wanting to engage discussions until and unless I develop sufficient mastery of the related subjects. One can simplify a view just so far, and no further, without risking losing the entire point.
The CO2 conclusions from Rasool & Schnieder ’71 remain a continual reminder, as Hercules was a constant reminder to Hera of Zeus’s infidelity, to me. Just the failure to recognize one simple thing — the rising altitude of the “effective” TOA — while drilling deeply into other details can still mean the entire enterprise is flawed.
In some cases, what’s missed may only chalk up Nth order effects that may represent at most 10% or 20% error. But in others? It’s not some minor error, but where the effect of it puts the entire conclusion on its head.
Until I know what we know, why we know it, and what part remains as unexplained residuals (and the distribution of those residuals in space and time are familiar patterns to me), I’m staying out as being too ignorant. I may know a few things but I now prefer to let the pros do the yeoman’s work and just try to follow along as well as I may. I’m just a dabbling hobbyist. Nothing more.
” you can see how the anti-GHG skin effect claim is plausible but straightforwardly debunked in practical terms. ”
If the skin effect is debunked, would not the oceans would have a lower heat content than they currently have?
The opposite JCH. If the skin effect was true, energy which currently goes into warming the surface layer, which mixes into and warms deeper layers, would instead go into evaporating the skin. The skin would be hotter, but as it would be negligible in thickness and underlain by unwarmed ocean, ocean heat content would be lower overall.
If increased IR flux mostly lead to more net evaporation from the ocean surface, rather than bulk warming of the ocean, that seems like it would not be particularly great news anyway: wouldn’t this latent heat just reappear as sensible heat when it rains, and transfer energy to the land areas where we live, amplifying the greenhouse effect on land?
The first thing I am going to do is check Scholar to see if a new paper has been written about the skin effect.
That does happen and I agree is one of the keys to understanding the land vs sea transient heating discrepancy (long term is due to heat capacity). Note this illustration I made which shows how one could set up the problem algebraically
I don’t see anything that refutes it. I remember back during the “hiatus”, Hansen commented that models may not be retaining enough heat in the oceans. Years ago, but I think I referred Paul to Hansen’s early method for estimating the coming change in OHC. I think he still uses it as basis for what he’s been doing.
I don’t see Minnett’s theory as to why GHGs warm the oceans as anti-AGW.
If you read the RC thread Paul links, there is a great deal of confusion as to what Minnett was saying.
JCH, I saw something that refuted it ‘way back in the 70s as a Geology undergraduate.
The rule-of-thumb thickness of the well-mixed layer*, tens of metres (hours to days) to hundreds of metres (decades), driven by the depth to normal and storm wave base (storms happen more than once a decade, but they’re areally limited so only stir things up along the storm track), and by tidal mixing. It’s how I knew immediately that Roy Spencer’s attempts at ocean-coupled models with ludicrously deep and ludicrously shallow mixing were GIGO. Of course the fact that the ludicrously deep and ludicrously shallow papers were published within a couple of years of each other was also a clue that he didn’t have a clue. And that he didn’t care about consistency, as long as it let him lowball AGW. This paper has some real-world examples of tidal mixing, which however doesn’t apply in deep water. The cells are about 50m high and vertical flow is about 0.05m/s, i.e. 180m/h (Fig. 6). So each cell mixes to 50m depth once or twice per hour. The circulation cells below waves extend to a depth comparable to the wave height. Two or three times, but it’s a diminished magnitude with depth rather than a sharp cutoff. Compare that to Paul’s “a few microns”. Some of those cells will of course have to hand off water to each other for it to reach the bottom of the mixed layer, but consider how frequently a wave passes compared to the diurnal cycle, and that ocean swells can break the back of huge ships by leaving the bow and stern perched and midships sagging.
[By Kraaiennest – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=3374567%5D
Since then I’ve encountered (and indeed mapped) contourites well below storm wave base, a kilometre deep or more. There are some crackers West of Shetland, deposited by the currents that are driven by thermohaline circulation. They help constrain when and if the NADW flow that drives the AMOC did or didn’t switch off. Those currents are powerful enough to erode ledges in earlier continental-slope sediments, and have vertical extents large enough that you have to adjust deep-water seismic data by season, depending on the depth to the sonically faster NADW. Other fossil examples I’ve seen are in the Pliocene west of Hainan and the Cretaceous chalk off Denmark, although they may be tidal**, and primarily contribute to lateral, not vertical mixing.
That’s not to say that there aren’t details to be worked out and modelling improvements to be made. But that can be done without resorting to ideas which are unphysical and defy reality.
* See Paul’s shaking-the-pan experiment.
** The chalk ones deposited contourites which were unidirectional, so if tidal there’d need to be a gyre that maintained direction between rising and falling tide. The Hainan ones were erosional so could have been to-and-fro. Indeed CNOOC interpreted them as tidal channels. But (a) they were coast-parallel for tens of kilometres and (b) there was clear seismic stratigraphic evidence that they formed at around 500m depth***.
*** Yes, tides go that deep. But to get serious erosion you need the acceleration that happens in shallow water, rather like a tsunami****.
**** Is that a record number of footnotes? 😉
Geologists, especially in my undergraduate days, were splittist when it came to wave base, since in the geological record we were restricted by observation to three categories: normal or fair-weather wave-base (characterised by asymmetric ripples and normal or dune/anti-dune cross-bedding), storm wave-base (characterised by hummocky and swaley cross-bedding*) and below storm wave-base (pelagic muds, silts and carbonates, perhaps interrupted by turbidites). There are other discriminators for very shallow water (symmetrical wind ripples) or periodic emergence (mud-cracks, evaporite minerals or pseudomorphs).
A rule of thumb maximum depth for entertainment of sediment by waves is about half a wavelength. Although deeper cycles, towards or off the bottom of the gif, can still move water molecules – just not clastic grains. So on reflection, a climatologist’s well-mixed layer should probably extend deeper than a geologist’s.
Oceanographers have since shown that it’s a continuum, with no sharp breaks between normal and storms. And it varies geographically, deeper in the oceans than in enclosed seas like the Gulf of Mexico. See Fig. 2 in Storm and fair-weather wave base: A relevant distinction? Still, my Mark One Eyeball says that 50m is not a bad estimate for enclosed seas, and 100-200m for open ocean – which is what I was taught back in the day. You still get fairly sharp switches in the resultant sedimentary structures because there are thresholds between aggradation mechanisms, mainly controlled by flow speed and water depth.
You’d choose a different threshold in Fig. 2B for diurnal, monthly or annual water mixing than for sediment entrainment that gets preserved in the geological record. You could model that but the simplest thing is to dangle thermometers under a buoy and see how deep the uniform temperatures go. I’m sure that’s been done. In fact I’ve seen some examples, although IIRC in places where they were looking for thermohaline currents or a thermocline.
Non-paywalled version of the wave-base paper and a good open-access review of contourites.
* Storms of course affect all depths, but because they’re rarer than normal conditions most shallow storm deposits get reworked, and only by a fluke would shallow storm-laid sediments be preserved in the geological record. And turbidites can contain flaser bedding, but there are other criteria to identify that it’s in a turbidite.
The cool skin effect has nothing to do with Roy Spencer.
It’s Minnett: SST.
I don’t see anybody in that field who has come out and disagreed. There is nothing in the cool skin hypothesis that disagrees with shaking pans, tides, etc. Minnett is an AGW ocean scientist. Widely published.
The responses to this nice and simple post remind me of the physicist who set up a Skype clinic where people could have their “theories” critiqued and discussed (although I believe she charged for the privilege)
We seem to be talking at cross-purposes JCH. I presumed you were referring to what Paul was referring to and I was adding to, which has nothing to do with Minnett and relies on zero convection or stirring in the water. So the microns-thick top layer just keeps heating until it evaporates, then the next microns-thick layer down, etc. Like his layer-by-layer sublimation analogue.
My debunking of that particular AGW-denying meme was by demonstrating stirring down to tens or hundreds of metres.
Still, it got me thinking again about contour currents, which led me to do a Scholar search for contourites in the Yinggehai (west of Hainan) and Qiongdongnan (SE of Hainan) Basins. Well I never! CNOOC now buy into contourites. Wonder if I had an influence? Suspect not, it was equity work so will have been compartmentalised and surrounded by (literal) Chinese Walls.
The QDN ones are driven by thermohaline circulation, the YGH ones were probably tidal and reworked turbidites shed off the Red River Delta. They see bidirectional structures, and a map of the Gulf of Tonkin shouts out “strong tides”. So in a sense they were half-right, but in 2001 they were insistent it was shallow-water tidal channels and barrier islands. The Monsoon is bidirectional too, summer-winter, but we were in too deep water at that time, and the Himalayas/Tibetan Plateau were lower hence weaker monsoons.Cool!
Where I was working was a zone of net erosion rather than reworking or deposition, as you’d expect from the strongest currents.
Sabine still offers her services:
http://backreaction.blogspot.com/p/talk-to-physicist_27.html
You might have found AT a side gig, older code!
BREAKING –
A Sky Dragon Crank is overseeing this thread on Reddit and comments in a food fight I won’t cite:
Here’s the paper allegedly showing empirical evidence:
https://www.researchgate.net/publication/338611709_Trapping_Radiant_Cold_Via_Mirrors
What’s funny is that I happen to know Pictet’s experiment! A great philosopher of science, Hasok Chang, wrote about it:
DOI:10.1007/S00016-002-8362-8
All this material won’t really be discussed because of the usual Climateball litany: you are playing games, I am not playing games, here is a paper so prove me wrong, etc.
I have cited Hasok in a previous chat with Berna:
Dave – what Minnett was trying to answer was the skeptics claim that back radiation cannot warm the ocean because it barely penetrates the ocean surface. Obviously the oceans are warming, and that sends them off looking for underwater volcanic eruptions and ship exhaust, etc.
The Response of the Ocean Thermal Skin Layer to Variations in Incident Infrared Radiation
Assuming that link works, look at the diagram at the top of 2485. What they are showing is an increase in DLW during cloudy skies reduces the loss of absorbed solar in the oceans, which will progressively increase OHC.
With no “hiatus”.
JCH – The climate system is far too complex for qualitative assessment by laymen. Fluid motion/evaporation also exchange heat between the ocean skin layer, upper ocean and atmosphere. Fortunately, there is no need for laymen to waste time on unproductive mental gymnastics. Measurements and validated model results are widely available.
Thanks JCH. I see it’s more complicated and we were talking at cross-purposes (although Minnett also contradicts the denier meme that Paul initially set up as a straw man, as that has the boundary layer heating up until it evaporates).
However the observational evidence that the oceans are well mixed on a vertical scale of tens of meters and on a time-scale of hours is still important. Without that the whole of the ocean behaves like the boundary layer, or like my Mars aerogel analogue above, with a very steep thermal gradient as it’s an almost perfect blanket blocking heat flow from the solid Earth. It would boil before you got deep enough for pressure to significantly raise the boiling point.
It needs more careful reading than I have time for just now, but feels like a cousin of the version of the GHG effect I posted further up, that if you make the top colder so it radiates less, then let it warm up so radiation out re-matches radiation in, everything underneath has to keep its existing thermal gradient and track that higher-elevation warming. In this case the top boundary layer warms, the (stirred, of course) thermal gradient below stays the same, so the deeper layers have to warm to track the top layer.
But most historical and much current SST data comes not from remote sensing, but from thermometers deep enough to be in the mixed layer. Indeed shipboard ones would surely be in the mixed layer at any depth, as the wake would stir the boundary layers. How much that impacts global averages would depend how they are weighted. So it also has a cousin in the form of mixing satellite and thermometer measurements over land. Of course land surface temperatures are typically not strictly surface either, the thermometers are placed several feet up.
I see that they do some sort of time averaging, but I worry slightly that they’ve made that cow so spherical by ignoring raindrops, breaking waves, and all but the lightest winds, that you’d conclude cows can’t walk because they have no legs, and they certainly can’t have pointy things like horns.
I have literally experienced that only once, in a dead flat calm in the northern North Sea. For some reason, all the squid came to the surface to play. The Spanish crew caught them on lines baited with orange peel or bread scraps (being squid they’d probably have grabbed anything though), and we had squid paella instead of freezer stores for days. Yummy!
Chubb – perhaps you can name a scientists who has spent more time than Minnett, and those skin layer scientists who came before him, studying the ocean skin layer than Peter Minnett, He’s preeminent. I rather doubt they are anything short of very knowledgeable about the oceans top to bottom.
Dave – the final product, SST, Minnett’s name is in on all of it, not just part of it.
What the other side is completely ignoring is how much heat would be leaving the oceans if Miinnett is wrong. They are also assuming how heat enters and leaves the oceans remains completely unchanged while there is significant build up of GHGs in the atmosphere. That portends implausibility.
The final product, SST, Minnett’s name is in on all of it. If you’re relying on SST, you’re relying on him.
Hansen said during the “hiatus” the models were underestimating the retention of heat in the oceans. Years before that he said to look for global warming in the oceans. Roger Pielke took the challenge because he thought the oceans would be cooler than the models.
“So, in a sense, this continued warming is due to an increase in absorbed solar radiation, but this doesn’t mean that this wasn’t caused by the initial increase in greenhouse gases in the atmosphere. It doesn’t somehow contradict what we expect from the Greenhouse effect.” – our host
Minnett is claiming the exact same thing.
JCH – My comment wasn’t very clear. No problem with Minnett, I was referring to the skeptics who think they can figure out on their own the physics that occurs at the ocean skin layer..
JCH, I was claiming the exact same thing in my third paragraph as Minnett said, more precisely and with focus on the uppermost layers, in the last paragraph of section 5 and the penultimate paragraph of section 6. Absent a discontinuity in the temperature profile, which he explicitly does not show, if warming due to GHGs moves the black curves to the right above the red stars, the bit below the red stars (extending much deeper than 5m because below that it’s still well-mixed on an hourly scale) also moves to the right. Ergo, the well-mixed layer has also warmed. Same as with the GHG effect in the atmosphere. If you move the radiating level (hence temperature) that matches solar irradiance higher, but the lapse rate stays the same, surface temperatures have to increase and therefore atmospheric heat content. It’s more a matter of perspective and reference frame than of fundamental disagreement.
Paul’s denier-meme skin effect is the one that was debunked, but it’s not the same skin effect as Minnett’s. I’m not sure what impact, if any, Minnett’s has on OHC, other than as a caution that remote-sensing SST measurements may be an underestimate compared to thermometer-in-water measurements, and an OHC estimate weighted towards the former may be a underestimate of the true OHC.
I see nothing in the text about OHC being wrongly estimated, although I’ve only had time to skim it. He’s not denying that the GHG effect will warm the surface, nor that that warming will propagate downwards and be quickly stirred into the well-mixed layer. His niceties vs. “the whole mixed layer warms not just the surface” falls into my “the rest is just detail” category. The result is the same in the end, just as a MODTRAN calculation is the same in the end as the equivalent single-elevation black-body equivalent. However, the thickness of that well-mixed layer, and how it varies across the globe, is very much a detail you need to know because 99% of the OHC is in that well-mixed layer, not in the skin.
Working through some references new to me from the contourite paper, I came across something climate-related although not directly AGW that surprised me: the NADW* penetrates down the South American coast as far as 36-38°S. That’s one heck of a flow! I presume it’s something to do with having an ocean at the North Pole and a continent at the South Pole. You can’t really get a NADW-scale meridional outflow in the Southern Hemisphere. As I noted, the contourites can be used to date flow onset (mid-Miocene), which we probably knew from the North Atlantic, but I wonder if anyone has mapped out whether there was, for example, a weaker one earlier that didn’t get that far south.
They also show a change from more turbulent (so more deep-ocean mixing?) conditions before the mid-Miocene, which presumably had climatic impacts. Although chickens and eggs, because opening of the Drake Passage and closure of the Central American Seaway were implicated in those changes. Of course that’s one of the things palaeoclimate models are good for: attribution and telling cause from effect.
* They call it Northern Sourced Deep Water in the abstract, presumably being agnostic as to the ultimate source, but it’s clear from the text that the NADW is now established as that source.
Aaaaaand….
We go full circle.
Delingpole things 9/11 was an in side job (apparently there’s a link to the agenda behind COVID as well. “Plandemic” anyone?
As always, there’s a root of the plausible upon which is built a firm belief in the highly implausible.
Hence group think, gateekeeping/pal review, perverse incentives, uncertainty, motivated reasoning, etc., become the climate hoax, the plandemic, mass hypnosis of billions to take vaccines, etc.
Speaking of the contrarian version of the thin layer argument, I stumbled upon an interesting version of it recently:
https://www.drroyspencer.com/2022/04/explaining-mauna-loa-co2-increases-with-anthropogenic-and-natural-influences/#comment-1258456
It took a while for Roy’s Hall Monitor to realize that ocean snow was not directly connected to the Revelle factor.
I am late to this post and Some things immediately strike me as being problematic.
First of all, the transmission of energy through the atmosphere so that it warms the Earth is primarily done in two ways. CO2 is involved in absorbing and releasing the initial IR emitted from the surface. In the 15 micron band there is an absorption curve that follows the frequencies of the IR being emitted vs. the resonating frequencies of the CO2 population. As one travels to the edges of the 15 micron band there is a drop off in the number of CO2 molecules that can absorb the IR being emitted. This follows the typical bell curve. To expand the absorption of iR at the edges of the curve, the IR intensity has to increase at those frequencies.Thus the saturation effect does exist in some form. The lack of more energetic IR photons at those edge frequencies being emitted from the Earth is a limiting factor.
In CO2 laser systems the expansion of a curve is accomplished by pumping energy into the system. As of yet there is no artificial method of forcing the Earth to emit these faster moving photons at the same frequency. The CO2 molecule is constrained in its frequency by the bonds of the Carbon and Oxygen molecules. The distribution of the frequency population therefore is limited.
Once the center bands are “saturated” they will not absorb any more IR energy. Instead they will pass it through to the upper atmosphere. This will offset any possible expansion to the outer edges of the 15 micron band.
Secondly the absorbed IR is not measured as heat until the captured energy is given up as translational motion by the CO2 molecule bumping into adjacent molecules. This is necessarily how we measure atmospheric temperature.
Molecules bumping into each other.
A change in vibrational state upon absorption of IR applies no change in temperature to the atmosphere. Only when the CO2 molecule collides with an adjacent molecule and gives up its added energy to the general atmospheric movement, is there heat transferred to the atmosphere.
Now, the claim that Feldman et. al, has measured the downwelling IR which is supposed to add higher and higher temperatures to the Earth’s surface.
For years and years, Gero attempted to isolate such a signal to prove that downwelling IR was increasing the earth’s temperature and he failed. Finally Feldman was contacted at JPL, and he used Models of the Earth’s atmosphere to finagle a reading from the data that purportedly showed that there was a downwelling signal.. What needs to be considered in context are several things:
1. The equipment in Alaska and the Great Plains was SPECIFICALLY designed to provide for DIRECT MEASUREMENT of a downwelling signal . This equipment had the highest S/N ratio of any yet invented but it could not do the job it was designed to do.
2. Only when models of the atmosphere were plugged into the calculations, not just the raw data, was a tiny signal finagled out of the data.
3. When the atmosphere is initially warmed it is because the IR is converted to molecular translational motion.
IF a CO2 molecule emits downward before releasing the energy as translational molecular moion, the IR energy has never warmed the atmosphere in the first place.
There is NO enhanced warming above the initial amount of energy that was originally emitted as IR from the Earth.
If a CO2 molecule absorbs IR, converts that energy to translational motion and then drops to ground vibrational state, then it is re-excited via collision to become energized to a higher vibrational state once more, The energy for that second energization has to come from somewhere.
It comes from the translational energy of other nearby molecules slamming into it. When this energy is absorbed from the surrounding motion of other molecules it necessarily cools the atmosphere by the exact same amount as it imparts when it captures an IR molecule and converts it to motion. There is no free ride. The Law of Conservation of Energy still holds true.
Einstein proved this at the time he won his Nobel Prize. These quanta of energy are specific.
Feldman and Gero needed to measure the downwelling signal they claim to have found and provide proof that this signal was not derived from the collisions whereby CO2 molecules were re-excited by translational movement of other atmospheric particles….Thus the energy was cooling the atmosphere first….
OR that the downwelling signal was not from CO2 molecules directly excited from the ground and thus had no part in increasing the Earth’s temperature initially.
Simply because you can come up with a non-measurable signal, you cannot make unsubstantiated claims as to its import, you also have to show that it is responsible for what you claim..
Butch,
I think you’re missing a key point about the CO2 effect being saturated. Even if it is, adding more CO2 to the atmosphere pushes the emitting layer to higher altitudes where it is colder. This, initially, reduces the outgoing flux, causing the lower troposphere, and surface, to warm. The atmospheric column that interacts with the radiation is, in some sense, not fixed.
Also, the downwelling flux must be warming the surface relative to what it would be in the absence of a downwelling flux. If the system is in energy balance (a state to which you would expect it to tend, even if it is never truly in exact energy balance) then the fluxes must balance everywhere, including at the surface. The energy flux from the surface is clearly much greater than the energy flux it gets from the Sun. Hence, there must be an additional energy flux that allows the surrface to be in energy balance. This is the downwelling flux from the lower atmosophere. The claim isn’t that has to be from “CO2 molecules directly excited from the ground”, it just has to be there, which we know it is because it’s been measured.
True. But we’ll be dead of CO2 poisoning long before we reach the stage where it matters for the GHG effect, beyond what’s already factored in.
As to the actual form it exists in, you had a nugget with your bell curve. Now Google “logarithmic concentration dependence”, and ask yourself why it isn’t linear.
Then Google line-by line calculation and consider the possibility that serious models, as opposed to simplified explanations for the layman, will deviate from logarithmic where required (as is the case in some exoplanet simulations), and indeed will deviate in thought-experiments that model CO2 at concentrations low enough for the response to actually be linear. And that even in models which are implemented as logarithmic over a certain concentration range to save CPU cycles, smart people will check where their parameterisation rules break down and replace them with the correct rules.
This paper: The runaway greenhouse: implications for future climate change, geoengineering and planetary atmospheres) (hey! – a climate model) shows that saturation can be and is incorporated at the concentrations where it matters. In a water-vapour runaway, you reach a physical limit on the amount of IR a steam atmosphere can emit, whatever the H2O partial pressure, and the planet just keeps right on warming until it’s red-hot and can emit directly to space through gaps in the water-vapour spectrum. Needless to say the present day and any conceivable future Earth can’t get there, whether for CO2 or water vapour, because long before that all but unicellular life would be extinct, and the problem would have solved itself.
Since we’re into analogies, one example from our host’s bailiwick is Hawking Radiation from black holes. Hawking used the analogy of a pair of virtual particles forming and the negative-energy one falling in. But, Katie Mack asks in her excellent popular-science book The End of Everything, how does the negative-energy one know it’s the one to fall in? She reassures readers that Hawking himself knew that was not a full explanation: the real explanation involves calculating wave functions and the scattering that the waves experience in the vicinity of a black hole, and despite the inadequacy of the popular analogy the full calculation does make sense if you do it all rigorously, using general relativity and quantum field theory. I bet even most physicists can’t do that though, so it’s the imperfect analogy or nothing. I can’t either, but I don’t go onto the Internet telling astrophysicists that Hawking got it wrong, the eponymous radiation doesn’t exist, and black holes don’t evaporate. Although apparently they may have hair after all.
Oh, and that Nobel Prize? That’s not what it was awarded for. Google will help there too.
>… he used Models of the Earth’s atmosphere to finagle a reading from the data that purportedly showed…
[…]
>> Only when models of the atmosphere were plugged into the calculations, not just the raw data, was a tiny signal finagled out of the data.
No matter how complex the physics, the mind-probing process to motive-impugn is always so simple!
They’re so consumed by their crackpot conspiracy theories that they don’t realise that voicing them in a purportedly scientific comment identifies then unambiguously as… well, the obvious.
By some serendipity, the Sky Dragon Crank I mentioned earlier also appealed to Albert’s authority. He also suggested that the greenhouse effect would necessitate an unequal treatment of molecules:
Their emphasis. Not sure why physicists would miss that elementary blunder. In fact my Climateball opponent has yet to formulate an explicit argument. But then obfuscation while waving arms is the point of these exchanges, isn’t it?
I have yet to see any realistic, functional definition of “saturation” from a fake skeptic yet, but did Butch really just say this???
Maybe Butch can actually explain what he means, but what he just said appears to be a claim that once saturation is reached, no more absorption occurs and as a result you get complete transmission.
I though the bogus “saturation” argument meant that CO2 already blocked everything so efficiently that nothing would get through and adding more CO2 still meant nothing would get through, so no biggy. Now, “saturation” means that the atmosphere gets turned into the radiative equivalent of a super-conductor?
Or is this a case where neither Butch nor I have any idea what Butch is talking about?
Bob Loblaw
I don’t think that could be correct and your understanding is correct It is my understanding that the energy in the absorbed outbound IR is rapidly transferred to the bulk atmosphere, which means that the CO2 molecules would rapidly return to a condition in which they could absorb more IR again. If it was the capacity of CO2 to absorb IR, it would “saturate” (in the sense of no longer absorbing IR) more quickly the less of it they were.
The RealClimate article by Spencer Weart that ATTP mentions in the OP is pretty good:
[emphasis mine]
Bob Lablaw, maybe this
https://webbtelescope.org/resource-gallery/articles/pagecontent/filter-articles/spectroscopy-101–how-absorption-and-emission-spectra-work?filterUUID=a776e097-0c60-421c-baec-1d8ad049bfb0
helps?
Yes, I’d missed Butch’s suggestion that once the bands are saturated they’ll pass the energy through to the upper atmosphere. This doesn’t make any sense. I think Dikran is correct that the molecules rapidly transfer the energy to the surrounding gas so can then re-absorb an IR photon. Of course, if there is no flux being emitted to space in some wavelength band, then adding more CO2 won’t change this.
However, you just need to look at something like MODTRAN to see that there is no wavelength band where there is no emission to space. However, some of the energy is emitted from regions in the atmosphere that are cold (i.e., at higher altitudes) and adding more GHGs pushes this emission to higher altitudes that are even colder, causing the lower troposphere and surface to warm so as to return to energy balance.
Dikran, David, and ATTP:
Thanks for the pointers, but I guess I was being too sarcastic/subtle in my response to Butch. I know very well that his statement (quoted by me) is horribly wrong, and I guess I was being too kind to think that he might not actually mean what he said. I first read Manabe and Wetherald (1967) nearly 40 years ago, so I’ve had lots of exposure to the physics over the years.
Eli has a good explanation of the thermal transfer to other molecules after IR radiation is absorbed:
http://rabett.blogspot.com/2013/04/this-is-where-eli-came-in.html
…and I have recently posted on IR absorption over at SkS:
https://skepticalscience.com/from-email-bag-beer-lambert.html
It’s just that the usual “CO2 is saturated” argument (as poorly explained by the denialiti) is based on the idea that by the time surface-emitted radiation reaches the upper atmosphere, it has all be absorbed. Increasing the absorption by CO2 doesn’t change that, as illustrated by figure 5 in my SkS post:
The error in that form of denial is to ignore the fact that the two curves in the above figure may both be essentially zero after 200 layers, but they are not the same after 20 or 40. (The layers and absorption coefficients in that figure are for illustrative purposes only – not a CO2-specific calculation.)
Butch seems to have taken denial to a new level: thinking that reaching “saturation” (whatever that means in his head) actually reduces the fraction of IR that is transmitted – allowing IR to pass from the surface to space unimpeded. (Well, just part of the IR? Who knows what lurks in his mind. The atmosphere is both saturated – for some IR – and completely transparent – for other IR at the same wavelength – all at the same time. That’s some magical radiative physics.
I suspect the latter Bob, and also suspect Butch is not the author of the gobbledegook he dumped on us.
The Tell is usually the inability to respond coherently to the gobbledegook being debunked. Which is typically manifested by the drive-by remaining a solitary example of silliness, or the silliness being parroted blindly with no response to the debunking. Or a combination of the two, where the perpetrator returns with another piece of copy-paste silliness and ignores the previous round. Duane Gish has a lot to answer for.
I was probably using saturated in a different way when I referred to the Goldblatt models, but yes, when the GHG effect is saturated in that sense you don’t get an IR-transparent atmosphere, you get a runaway greenhouse and a cooked planet.
Willard, I’d file that argument alongside “because tigers have stripes, cats can’t have kittens”.
Although perhaps, since the pre-quantum-mechanics thermodynamic arguments against the GHG effect are, well, pre-quantum-mechanics, that should be a Schrodinger’s cat which may or may not have kittens 😉 .
Not sufficient to “debunk” the greenhouse effect. Have to explain why we are warming with the same pattern as greenhouse gas warming. Good luck with that.
Hmm. Two tries to post a response, and it’s not making it through. Re-reading the thread, I can see I’ve made some of the points above anyway, so maybe it doesn’t matter if my latest went into the bit bucket.
Bob,
Found them in spam. Not sure why. Have released the first one.
Thanks. I wondered if it was because I had several links, or what. At least one of the links I’d already used earlier, so maybe that’s what makes it think it’s spam.
Bob,
There is a limit to the number of links that can be posted in a comment, but I’m pretty sure it’s bigger than 2. It does sometimes seem a bit random. I did find someone else’s comment in there too.
Thanks for Eli’s post, Bob.
***
I think my Sky Dragon Crank might be arguing for something stronger than “because tigers have stripes, cats can’t have kittens,” Dave. By his logic, no two molecule could have different properties!
Try using tiny url.
Glad to see that the pot is stirred a bit.
The concept of saturation of absorption effect is what is discussed. Since there is some question about the definition. The absorption cannot increase further once the effect is saturated. therefore the IR must go somewhere. It passes through to a higher altitude. At higher altitudes the amount of IR absorption drops off due to the CO2 molecules being farther apart. You can easily observe the emission curve and see that at the center there is an area of lower absorption due to the spike which is extremely visible. This should put to rest the argument that others are putting forth about what saturation means in this context.
———————————————
In any case, the IR which does get absorbed into a CO2 molecule then causes the molecule to reach a higher vibrational state.
So now we have a CO2 molecule in a higher vibrational state. HOWEVER No increase in temperature has occurred. See below…
How do we measure temperature in the atmosphere? We measure the effect of atmospheric particles in motion. Against each other. (Translational motion where the particles collide.)
NOT THE NUMBER OF CO2 MOLECULES IN AN EXCITED VIBRATIONAL STATE. This is NOT how we measure atmospheric temperature.
This may seem simple to some,
but some others seem to think that IR absorbed by CO2 immediately imparts heat to the atmosphere. This is not the case.
The vibrational energy must be converted to heat energy. It does this when the CO2 molecule collides with adjacent atmospheric particles. The CO2 molecule leaves its heightened vibrational state and the molecules it collides with gain momentum. THEN and only then can we measure the heat. The CO2 molecule returns to the ground state.
Granted that some extremely few CO2 molecules will experience decay and emit an IR photon before colliding with adjacent atmospheric particles.
In that case there are several situations that come into play.
ONE is that the IR energy has not yet contributed to atmospheric heat. because the CO2 molecule has not contacted another molecule and imparted its energy to the atmosphere at large before the decay. NO HEATING HAS OCCURRED. The re-emitted IR photon can escape the Earth and there will be a net loss of IR energy to space. Or the re-emitted IR energy can contact the Earth or another CO2 or H2O molecule. In that case the energy is simply expended as it would have been normally. NO INCREASE in temperature over the amount that would have occurred from the initial warming would be evident.
TWO is that there is a difference in the time to collision with adjacent molecules and the time to spontaneous emission of an excited CO2 molecule. This time difference is on the order of a billion to one. A CO2 molecule will collide with other atmospheric particles a billion times as fast as the time to emit. Therefore the re-emission effect is minimal.
SO atmospheric collisions creating heat in the atmosphere are a billion times as prevalent as CO2 re-emissions. CO2 re-emissions are miniscule compared to the conversion of IR through direct collision with other atmospheric particles.
THREE a CO2 molecule can get re-excited by collision. If it is higher up in the atmosphere it can emit to space or (towards Earth) there is no 1 to 1 ratio as the curvature of the Earth provides for more to escape to space than to impact the Earth.
The re-excited CO2 molecules follow the same relaxation parameters and so their absorbed energy from collision is predominately converted back to atmospheric heat.
HOWEVER THIS DOES NOT INDICATE THAT THERE IS ADDITIONAL ENERGY GIVEN OFF AND COLLECTED BY THE EARTH!!!!!
WHY? Because to become re-excited the CO2 molecule has to absorb heat energy from the surrounding atmosphere.. IT COOLS THE ATMOSPHERE WHEN IT DOES THIS!!
There is NO FREE RIDE. Energy cannot be created from nothing. But this is what those who do not understand the Law of Conservation of energy would claim.
There is more to the situation than I have toughed upon but this is the basic scenario. A finite amount of energy is emitted. The CO2 captures most of it and immediately converts it to atmospheric heat. (Greenhouse effect)
A Secondary IR emission from CO2 is theorized which supposedly increases the temperature at an increased rate. This is not proved because it requires double use of the same energy which violates the Law of Conservation of Energy.
Butch,
I think you have a rather confused idea of how the greenhouse effect works, although your description of what saturation implies almost gets there. Consider the following.
The only source of energy (ignoring geothermal) is energy from the Sun. Some of that energy is intercepted by the Earth. About 30% is reflected (albedo) and the rest absorbed. The amount absorbed is about 240 W/m^2 (averaged over the surface of the Earth). The system will then be in energy equilibrium when the amount radiated back into space is also (on average) 240 W/m^2. If you then equate this with an effective blackbody temperature (i.e., the temperature of a blackbody that emits 240 W/m^2) you get a temperature of 255 K. This is the effective radiative temperature of the Earth. If you observe the Earth from space, measure the outgoing spectrum and use this to determine an effective temperature you would get about 255K.
If the Earth had no atmosphere, or one that was transparent to the outgoing flux, then all of the energy would be radiated to space from the surface and the average surface temperature would be 255K. However, the Earth does not have an atmosphere that is transparent to the outgoing radiation. This means that some of the energy emitted to space is emitted from within the atmosphere, rather than from the surface directly.
However, the Earth’s atmosphere (troposphere) has a temperature that decreases with increasing altitude. This temperature gradient is essentially set by convection, but that isn’t all that relevant here. Given this, if the surface temperature were 255 K, this would mean that all of the energy would be radiated from regions that are either 255 K (directly from the surface in some wavelength bands) or colder (from within the atmosphere). Since the energy radiated depends on the temperature, the amount of energy radiated into space would then be less than 240 W/m^2 and we’d be receiving more energy (per square metre per second) than was being emitted into space and the system would warm. This would increase the outgoing flux and this warming would continue until the outgoing flux (on average) matched the incoming flux from the Sun. In a sense, the system would simply be retaining some of the incoming solar energy which then warms the system until energy balance is attained.
This is essentially the greenhouse effect. Because some of the energy emitted into space comes from within the atmosphere and because the temperature in the atmosphere decreases with altitude, the surface has to be warmer than it would be in the absence of an atmosphere (or one that was completely transparent) in order for the system to be in energy balance.
The greenhouse effect does not imply energy created from nothing. It is simply a consequence of the greenhouse gases causing the surface and lower troposphere to be warmer than the effective radiative temperature so that the outgoing flux matches the incoming flux.
I would have thought the ratio of emission up- and down-wards is pretty close to one. The height of the effective emitting layer is only about 10km (within an order of magnitude) is very small compared with the radius of the Earth (around three orders of magnitude larger), so the curvature of the atmosphere is pretty negligible on that scale. Also any IR that is emitted at a shallow angle has a lot of atmosphere to get through to escape to space, so it is probably going to get reabsorbed.
Dikran,
Yes, the surface area difference between the different emitting layers is negligible.
You do not seem to grasp the process by which CO2 molecules can re-emit.
Either they are directly excited by
A.) absorption of an IR photon from the Earth…. Or they are excited by
B.) collision with other atmospheric particles.
If by A.) absorption it has never warmed the atmosphere to begin with, so re-emission is simply allowing the IR to complete the same amount of warming that it would have had the IR photon not been re-emitted.
If by B.) the CO2 molecule is taking heat energy out of the atmosphere before it can place it back into the atmosphere or Earth’s surface by IR re-emission.. The energy has to come from some place. It cannot simply appear out of nothingness.
The original concept of global warming was that the IR was converted to heat energy in the atmosphere once the CO2 molecule slammed into other molecules.The IR did not radiate directly into space. Well and good.
Now some climate scientist (probably a Geologist rather than a Physicist) ignored the Law of Conservation of Energy and came up with a theory that the time constant for delaying the loss of energy to space could be explained by the re-emission of IR from CO2 molecules in the atmosphere as the CO2 population increased.
Problem is, the original amount of energy was never increased. The speed at which IR is emitted from the Earth or its atmospheric layers is such that it will escape quite rapidly.
—————————————————————————————————-
I stop typing here because more information will only serve to confuse a number of people.
Butch,
I don’t think it’s others here who are confused. Can I ask that you reflect on this comment before responding further.
I’ll add that if the only form of energy transfer was radiative diffusion, then the greenhouse effect would be even stronger than it is. I can’t remember exactly what the calculation suggests, but I think the surface would be something like 66K warmer than the effective radiative temperature, rather than ~33K warmer.
As for differing emitting layers, The CO2 that is excited, will emit at higher and higher percentages as one rises in the atmosphere.
Why? because the atmospheric particles are farther apart. The CO2 molecule will not collide as quickly and give up its energy as heat or translational motion. This eventually at certain heights allow enough separation of the particles so that emission from the CO2 molecule can occur.
This allows IR to be emitted to space. At lower heights where there are more atmospheric particles the collision with those particles causes the energy to be given up (once more) as heat energy.
Again, the atmospheric particles are constantly colliding with one another, Sometimes exciting and sometimes de-exciting CO2 molecules to a higher vibrational state.
In the event a CO2 molecule is de-excited or relaxed to ground state, after having been directly excited by IR absorption, then warmth is added to the atmosphere as a whole. but no more than would be expected from the nominal greenhouse effect.
In the event that a CO2 molecule has been excited by collision with other atmospheric particles, The dropping of that CO2 molecule to a ground state will NOT add any warmth to the atmosphere, because to become excited the CO2 molecule has to first remove heat from the atmosphere.
This is why the enhanced greenhouse effect cannot warm the Earth through more CO2 molecules.
As a percentage of the total energy, the IR cannot re-emit in sufficient quantity to allow warming through this mechanism.
Butch,
It seems clear that you really don’t understand this very well at all. If you’re not willing to at least spend some time thinking about what I said in the comment I highlighed earlier, it might be best if you over-confidently explain your understanding of the greenhouse effect on sites that don’t mind spreading misinformation, rather than doing so here.
However, you posit a condition that does not exist. Energy essentially travels through the atmosphere by two processes. That energy can be converted one process to another and the process that predominates is the conversion of IR to motion of atmospheric particles.
The other process of exciting a CO2 molecule by collision and then using that excited molecule to add energy to the atmospheric soup is essentially worthless in adding heat because the process requires the removal of energy from the same atmospheric soup before it can give up the energy it has absorbed. Please tell me the way you believe that CO2 molecules can be raised to a higher vibrational state other than the two ways I have outlined.
Please provide the response I have asked you for, Rather than talking down to me.
I have read several of the links you have provided but I do not find them persuasive at all.
Yes i understand the theory that CO2 causes additional delay in the release of energy to space. But when someone as yourself will not even look at the mechanisms by which energy is transferred through the atmosphere but simply says no not possible….
It makes you wonder what site is spreading misinformation.
BTW who else has written to you with the same position?
Butch,
I don’t actually know what response you’ve asked for. I don’t really think whether or not you find the links persuasive is all that relevant.
I have mentioned the mechanisms through which energy is transferred through the atmosphere. In fact, the mechanism that largely sets the tropospheric temperature gradient is convection. I also pointed out in an earlier comment that if the dominant energy transfer mechanism was radiative diffusion, then the greenhouse effect would actually be stronger than it is, because radiative diffusion requires a steep temperature gradient. The reason it doesn’t dominate is because the temperature gradient passes the convective stability limit before radiative diffusion can become the dominant energy transfer mechanism.
Based on what you’re saying, I would guess that you’ve never actually looked at a detailed calculation of how energy is transferred in an atmosphere. It takes more than just hand-waving about CO2 molecules absorbing and re-emitting photons, or transferring energy via collisions.
Actually, this post by Science of Doom goes through some of this in a bit more detail.
The total point of my posts is to show that energy cannot be created and destroyed in the atmosphere, no matter the method of greenhouse gas hand waving.
LW IR . emitted from the Earth has essentially two sources. The sun and geothermal origins.
We can ignore geothermal origins unless you are of the opinion that mantle variations are causing more or less energy to warm the surface.
SO that leaves us with the Sun’s effects and the conversion of that energy to LW outgoing radiation from the surface. It is a finite amount at any given time. Therefore the amount of energy derived from the outgoing LW radiation at any given time is finite.
Most CO2 resonant IR is in the 15 micron band. We can ignore the IR outside this most important band for now.
Most is absorbed in a curve whereby the center of the curve has the most energy absorbed.
At the edges of the curve less is absorbed.
Some is absorbed by H2O, we shall ignore this absorption also.
There is a finite amount of energy absorbed by CO2 in the atmosphere.
The two main methods of energy conversion dealing with the CO2 population is 1) direct IR absorption and excitation to a higher vibrational state. And 2) collisional excitation. with other atmospheric particles.
By necessity direct excitation bypasses the conversion by collision method when we consider where the energy comes from and where it goes. It comes from the Earth. And in a billion to one ratio it is converted to atmospheric heat. The relaxation to emission time is approximately one billion times as long as the time to collision. Therefore this ratio holds for the pathways for the energy released from the CO2 molecule.
by a huge margin the IR is converted directly to atmospheric heat. (The greenhouse effect.)
This process gives a declining logarithmic effect of increase in temperature.
However this was not dire enough for some people and they enhanced the effect by claiming that the rise in temperature was in fact an increasing logarithmic one.
TO accentuate the point it was claimed that CO2 enhanced global warming rapidly.
To examine this Several people took it upon themselves to look at the ways that energy traveled through the atmosphere. J. Halpern being one of them as Eli Rabbit. He was one of several that I read about in discussions.
However long ago I had learned about the conservation of matter and conservation of energy.
I could find no additional source of energy for an enhanced greenhouse effect. Therefore I decided to look at the process by which the greenhouse effect as provided by CO2 occurred.
It was rather obvious. CO2 absorbs IR at a ratio of a billion to one and converts it to atmospheric heat. in that rare instance that an IR photon is re-emitted….it is then immediately captured and converted to heat. It is a straightforward process. No re-emission over and over again.
So how do we explain the fact that higher in the atmosphere there are vibrationally excited CO2 molecules? Simple, they are excited by collisions.
All throughout the atmosphere there are collisons occurring which both excite and return CO2 molecules to ground state. Once excited by this method the energy given up by a return to ground state is simply a return to the Status Quo… There is no additional energy added to the atmospheric heat. If that one in a billion emission should occur after a collision, it simply is absorbed by the next CO2 molecule, but it like the relaxation of an excited CO2 molecule from collision, it does not add heat to the atmosphere. It too was energized from the original IR emission from the Earth.
so I see that the claim that re-emission of IR from excited CO2 molecules in the air has been made to claim that the energy transfer is slowed so that the air is warmer. BUT the total amount of energy over time is not increasing . Radiation to space increases with separation of CO2 molecules so that a released IR photon can travel outwards without colliding and being captured by another CO2 molecule. Consider also that the total of all atmospheric particles come into play when trying to calculate the rate of emission to space.
Don’t be like the obstinate King who was fooled by the two tailors who had a story to tell about their magnificent clothes, and then he marched through town completely naked.
Just answer the basic question as to where the additional energy in the atmosphere comes from..
I know that I am not the smartest man but I do know that I have a question that is not answered on this site.
Butch,
Here’s the deal. You’re in AT’s home right now. He will talk like he sees fit. If that does not work for you, there are lots of other websites where you can comment.
Also, you’re basically trying to mansplain the greenhouse effect to a physicist. If that’s not talking down, I don’t know what is.
Finally, try to shorten your interventions. That will help people identify your requests.
Best,
The problem with Butch’s posts is that there is a lot of basic stuff that is not in dispute, mingled with blaringly wrong conclusions that do not follow from the basic stuff. We are looking at dismissal of any effect, using phrases such as “a billion to one”, “effect is minimal”, “do not understand the law of conservation of energy”, “re-emissions are miniscule [sic]”.”it will escape quite rapidly”, etc.
Yet Butch never actually puts any numbers on this, or points to a place where he thinks the calculations have been done correctly. The basic stuff he parrots that is correct, is what is in the radiative transfer code and climate models that actually do calculations. But when the calculations are actually done, they do not lead to the bizarre world where Butch resides.
Here is a clue (or two) Butch.
We know that molecules absorbing IR nearly always transfer the energy to other molecules via collisions.
We know that molecules exchange energy with other molecules far more often than they emit or absorb radiation.
We know that energy (in all forms) needs to be conserved.
We know that people that have actually done the math get a different conclusion from your hand-waving.
[No playing the ref, Butch. Sorry. – W]
Hi Bob, Please allow me to accept your conclusions for the first three items you post about my observations. I am mortified that you think i was talking down to others about these things. . It was included as basic background information.
For the last, Please calculate the time to collision in the lower atmosphere vs. the time to spontaneous emission of the CO2 molecule. While I am not exact i have heard this referred to as a billion to one time difference. Thanks.
The back of the napkin calculations give 0.07 NS for atmospheric collisional time.
A CO2 molecule bending motion transition with a 15 micron wavelength and about 1/30 the matrix element should have …..a lifetime of around 0.2 seconds
.
Not exact but fairly close to the relationship I cited. But you are probably much more competent than I to calculate the times.
Butch,
Yes, this is obvious. I think most of the people who comment here are well aware of that energy cannot be created and/or destroyed. The total point of my responses to you is to try and explain that the greenhouse effect does not assume that energy is somehow created and/or destroyed in the atmosphere. If you think that the greenhouse effect implies this, then you don’t understand the greenhouse effect. Maybe try and understand the greenhouse effect before coming here and lecturing people about something they already know.
“Please provide the response I have asked you for, “
Butch I have explained to you why your third point was factually incorrect, but you have not engaged with what I wrote.
Butch: “Rather than talking down to me.”
Also Butch “I stop typing here because more information will only serve to confuse a number of people.”
Nobody would claim that any energy is created in the atmosphere and it certainly isn’t a part of the stated mechansim of the greenhouse effect. All of the energy involved comes from the sun, it is just that GHGs cause some of the energy radiated from the surface to be returned to the surface, causing it’s equilibrium temperature to be higher than it would be in the absence of backradiation.
The absorption of outbound IR will cause some increase in the thermal energy of the atmosphere, but IIRC the main way the atmosphere is heated is by convection. The greenhouse effect does cause warming of the atmosphere, but my understanding is that this is indirect via warming of the surface.
Butch,
“The total point of my posts is to show that energy cannot be created and destroyed in the atmosphere, no matter the method of greenhouse gas hand waving”
If your starting point is that the thousands of PhDs who study atmospheric physics have missed the application of the first law of thermodynamics to the problem, but you have and will now teach them, you have no hope of learning.
Only if you start from the perspective “This seems to me to break conservation of energy, please help me understand my mistake” do you have any hope of enlightenment.
Good luck.
[Mod: I think we’re done here. Thanks for stopping by.]
Option Two is the winner I see.
And my thanks re Eli were due to Bob, I also see.
“, but my understanding is that this is indirect via warming of the surface.”
I was thinking about this while I was in the gym, and I suspect that isn’t right because all things being otherwise equal (e.g. solar radiation at the surface won’t change) so the way the surface warms presumably is by an increase in back-radiation. So presumably the decrease in IR radiated due to the increase in the effective radiating layer causes energy to accumulate in the atmosphere (because more is coming in than going out), and the thermal structure of the atmosphere (largely due to convection) means that the surface must warm for the new effective radiating layer to emit as much as it did before.
The important thing though is that all the energy involved comes from the Sun, none is created or destroyed, the GHE just modulates the way that the energy escapes to space.
Dikran,
Yes, that is – I think – the right way to think of this. The amount of energy coming in is unchanged and the system wants to tend to a state in which the amount of energy going out matches that coming in. If the radiating layer moves to a higher altitude then the amount going out goes down and energy accumulates until the amount going out has increased to match that coming in. Other processes (convection) distribute this energy so that there is a largely unchanged (with caveats) temperature gradient in the atmosphere, and the surface will warm as a result.
I know some people don’t like the blanket analogy, but I think it’s quite good. Your body generates a fixed amount of energy per second. If you are lying under a blanket, then the outside temperature is fixed, but the temperature on the inner surface of the blanket will be higher because there needs to be a temperature gradient in order for the energy to be conducted through the blanket. If you add an extra blanket, the outside temperature stays the same, but the temperature on the inner edge of the blanket goes up because the temperature gradient through the blanket is fixed but there is more blanket through which the energy has to travel. Over-simplified, probably, but roughly the case.
Yes, unfortunately analogies are often only useful for an audience that is disposed to agree with you. They are useful because the are gross-simplifications, they can easily be evaded because they are gross-simplifications. I like the blanket analogy because like a blanket, the atmosphere is warmed from beneath, so any energy that goes back to the surface somehow initially originated from there – the GHE doesn’t violate the first law of thermodynamics any more than a blanket does.
I like the blanket analogy ATTP, although I use a duvet, because it lets you introduce the time delay.
It’s a warm evening so you go to bed with a thin sheet and no duvet. It’s a clear sky so it cools rapidly and you wake up shivering at three in the morning. You put on a duvet, but you don’t warm up immediately. It takes time to build up that new thermal gradient, with the top of the duvet at the temperature the top of the sheet was at, but the duvet initially at that temperature all the way through.
I see I missed the “only a geologist” dig on my first skim through the gobbledegook. Priceless piece of D-K, when this geologist clearly understands it better than the gobbledegooker does. In part because I started with the assumption that I was the dumbest person in the room, and educated myself at places like SoD and SkS. In part because my Geology PhD was one-third thermodynamics. Although that was all classical thermodynamics so I’d still have been vulnerable to the heat-can’t-flow-from-cold-air-to-warm-ground fallacy.
Which gives me an excuse to introduce a cousin of the Katie Mack extract I posted earlier. The counter is of course “How does the CO2 molecule know up from down when it’s emitting a photon? And how does it know that the ground is warmer than itself and the CMB colder?”. Spooky action at a distance? Applying 19th-century physics to quantum mechanics never ends well. Although actually you don’t need quantum mechanics. The kinetic theory of gases provides another answer. “How does the molecule know how warm it is if temperature is an ensemble property of a bunch of molecules not a property of one molecule: the average molecular kinetic energy being proportional to the absolute temperature?”.
Dave_Geologist doubly ironic as the originators of the idea (Fourier, Tyndall, Arrhenius) were pretty much all physicists and many were leading figures in thermodynamics (Tyndall was the translator for the early English translations of Clausius’ textbook). The idea that they missed a violation of first law of thermodynamics is a bit silly.
Butch ask me for this:
This has been done in the following post at Eli Rabett’s blog. I linked to this earlier.
http://rabett.blogspot.com/2013/04/this-is-where-eli-came-in.html
But since you read all the links that people provide, and you find them unconvincing, I suspect that it will not change your mind.
Regarding the frequency of hearing “this violates the laws of thermodynamics” rampant in AGW contrarians, I always figured that there is a chance its overuse is due to connections between AGW denial and evolution denial. “Evolution violates thermodynamics” has been a go-to in the promoters of “creation science/intelligent design” for decades. It was a simple search/replace when they rebranded “creation science” as “intelligent design”, and another search/replace let’s someone convert all the previously-prepared technobabble to cover “greenhouse effect”.
“this violates the laws of thermodynamics” is very much like “the rise in atmospheric CO2 is natural” in that it is an indication that productive discussion is extremely unlikely. You have to be *extremely* resistant to correction to still be making either of those arguments in 2022 as they have been discussed so widely and are so easily shown to be wrong.
Dikran: you could say exactly the same thing about its use by the creation science/intelligent design people.
“Dikran: you could say exactly the same thing about its use by the creation science/intelligent design people.”
At least in those cases people tend to be more open about their priors.
As for the “conservation of energy” aspect of atmospheric temperature profiles, the basic principles are that any atmospheric layer that has a net gain of energy will warm, and a net loss means cooling. Atmospheric temperature profiles will be steady when there is no net gain or loss. All layers work together – there is no “summary” that will give you the full picture and any attempt to focus on what happens at one single height will leave something out.
Manabe and Strickler is the earliest paper that provided a detailed radiative transfer model (one dimension) that looked at this:
https://journals.ametsoc.org/view/journals/atsc/21/4/1520-0469_1964_021_0361_teotaw_2_0_co_2.xml
Here is figure 1 from that paper:
The way the model was run was to start it off with an initial temperature profile (they tried one hot, one cold), and then advance through time doing the absorption, emission, and net energy balance/temperature change calculations until the profile stabilizes.
The left side shows what you get with only radiation fluxes. The right side includes a convective adjustment – basically crudely adding convective fluxes. ATTP alluded earlier to the difference in the greenhouse effect if radiation were the only energy flux on the atmosphere. This figure shows it explicitly.
We can also see that it takes less than a year for the atmosphere to stabilize – there is no ocean heat capacity in this model. (Also no seasons, or day/night. This used 1964 – or earlier – computing power, after all.)
And there is no “violation of thermodynamics” in sight.
When the Sky Dragons attack here is another arrow to put in your rhetorical quiver.
Energy can move from a colder region to a hotter one:
https://physicsworld.com/a/energy-can-move-from-a-colder-region-to-a-hotter-one-but-the-second-law-of-thermodynamics-is-safe/
“The researchers say they will now study other geometries beyond 2D structures. “We have already shown in a recent preprint that crosscurrents can exist in 3D systems, meaning that the current flows from cold to hot throughout an entire 2D surface, instead of just along a 1D line,” explains Martin-Delgado. “But we can even think further and speculate about higher dimensions – for example; a 4D cube which would have a 3D cube as one of its boundaries. Thus, the Second Law could be apparently violated in a 3D world that is the boundary of a 4D system.”
Has anyone ever seen one of the greenhouse effect deniers be able to calculate a spectrum that matches what we measure with an infrared spectrometer?
Matching those spectral observations is the most basic requirement to support a claim that you understand anything about radiation in the atmosphere, and in literally decades of complaining I haven’t seen a single case.
Having Dragon Cranks calculate would already be quite a feat. I have been taking a day off trying to make one understand quantifiers and presupposition logic yesterday. All I got is a little play.
The short of it is that they can’t even identify the Greenhouse Theory. Some deny it exists. Others claim having refuted it. And yesterday’s companion tried to make the two stances compatible by appealing to versions of it.
In Sky Dragon Cranks land, it is possible to refute all the versions of a theory that does not exist!
They’re usually into weapons. If the Greenhouse Theory is refuted, an anti-aircraft missile could not hit the broadside of the Milky Way.
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