By W. A. van Wijngaarden, Department of Physics and Astronomy, York University, Canada and W. Happer, Department of Physics, Princeton University, USA
We discuss the basic ways greenhouse gases affect radiation transfer in Earth’s atmosphere. We explain how greenhouse gases like water vapor, H2O, or carbon dioxide, CO2, differ from non-greenhouse gases like nitrogen, N2, or oxygen, O2. Using simple thermodynamics and fluid mechanics, we show that the atmosphere of a planet with sufficiently high concentrations of greenhouse gases must develop a convecting troposphere between the surface and the tropopause altitude.
The planet must also develop a non-convecting stratosphere for altitudes above the tropopause. In the simplest approximation of an atmosphere that is transparent to sunlight and has frequency-independent opacity for thermal radiation (an infrared gray atmosphere), one can find simple formulas for the tropopause altitude, and for the altitude profiles of pressure and temperature.
The troposphere is nearly isentropic and the stratosphere is nearly isothermal. The real atmosphere of the Earth is much more complicated than the simple model, but it does have a troposphere and a stratosphere. Between the surface and the tropopause the entropy per kilogram of real tropospheric air increases slowly with altitude. The entropy increases much more rapidly with altitude in the stratosphere. The stratosphere has a nearly isothermal lower part and a hotter upper part due to absorption of solar ultraviolet radiation by ozone. The thermal opacity of the real atmosphere has a complicated frequency dependence due to the hundreds of thousands of vibration-rotation transitions of its greenhouse molecules.
Unlike the simple model where nearly all radiation to space originates at the tropopause altitude, radiation to space from Earth’s real atmosphere originates from both the surface and all altitudes in the troposphere. A small additional amount of radiation originates in the stratosphere. When these complications are taken into account, model calculations of the thermal radiation spectrum at the top of the atmosphere can hardly be distinguished from those observed from satellites.
You may download a printable version of Atmosphere and Greenhouse Gas Primer here.
Excellent paper! Looking forward to all the heavy hitters to weigh in….
The more I argue with Nick, Frank, the better paper I realize it is. Unfortunately it is too complex to serve as a basis for argument regarding what importance the addition of CO2 and a few other trace gasses have for future climate.
For a ‘primer’, it is a heavy lift, particularly for folks like me whose quant credentials are a bit dated, to say the least. Obviously, a lot easier for you!
I think the structure of these papers is that van Wijngaarden does the maths, and does it well. Then Happer writes the dot points, and gets it all wrong.
BTW, Frank. Way back on the thread following my posting about setting utility rates you asked me “What’s with Wyoming’s Governor?”
Gov. Gordon went to some conference in the East and stated that Wyoming would strive to become “carbon negative”. The minute he returned a bunch of state house members and senators challenged to debate him and he quickly accepted. Too quickly for he has now backtracked.
The connection between that story the present one is that the CO2 Coalition offered to act as expert advice on climate change to those 30 state legislators. I wrote a letter to one of the legislators, saying that arguing about climate change and any role of CO2 in it was the wrong approach as the topic is too complex and arguing about it would defuse the whole debate. Much better to argue the disastrous and catastrophic economic consequences for Wyoming and its citizens of the whole net zero/carbon negative religion. Focus on costs and economics — money issues people grasp immediately.
Dr. K, thanks for the update. I agree that focusing on economics is the best tactical approach to the problem of climate alarmism. Hopefully, at some future time, the political situation will allow for an unbiased review of the science.
Geez.
that all sounds like stuff that would be going on in a coupled non-linear chaotic system.
But as we already know, there’s nothing left to discover about such systems, because the science of such systems has all been settled. Apparently.
Right – just ask Dr Koonin
I always had problems with the constant adiabatic expansion lapse rate assumptions in undergraduate meteorology. It seemed it may well be 100% correct at the surface but must, necessarily become 100% incorrect as altitude increases.
Putting my possible misunderstanding aside, I went to do something else for other reasons. But I found that similar assumptions get made elsewhere in science.
Commenting on a term paper our professor had us write in a grad school, I remember him cautioning us with the words that in publications it was wise to “Never make a provable assumption.”
Question, what would be the winter effect of multiple anomalous deep stratified bands of water vapor in the Stratosphere on the Polar Vortex this winter, will it be more disruptive, or will it add stability?
The Quasi-biennial Oscillation (QBO) (nasa.gov)
No mention of N2O? Why? Why is this gas…..300 times more potent as a GHG than CO2…. always ignored?….neglected? We gotta pay proper respect to this fav of dentists, no?
N2O may be “300 times more potent as a GHG than CO2” on a molecule-to-molecule LWIR absorption/reradiation basis, but look at its minuscule concentration level in the atmosphere compared to CO2: 334 ppb wt. versus 413 ppm wt. (both referenced to CY 2021).
— ref: https://www.epa.gov/climate-indicators/climate-change-indicators-atmospheric-concentrations-greenhouse-gases
That a 1:1240 concentration difference, far overwhelming the 300:1 molecular level LWIR absorption/reradiation difference.
That’s why atmospheric scientists—even most CAGW alarmists—don’t waste time discussing atmospheric N2O.
The world should have more N20 in the air- we all need a good laugh. 🙂
Doesn’t that mean that N2O is 100ppm CO2 equivalent for LWIR? Doesn’t it also last longer in the atmosphere?
1) No.
2) CO2 has been in Earth’s atmosphere continuously for, oh, the last 4 billion years or so . . . not so for N2O. So, no, nitrous oxide does not “last longer” than CO2 in Earth’s atmosphere.
It also raises the issue that the research-authors and media lap dogs rarely mention that the formal comparison is between equal weights of CO2 and a particular GHG, but they are usually measured in the atmosphere as mole-fractions of CO2 and mole-fractions of the particular GHG. Because they all have different molecular weights, the apparent effect of a GHG such as methane has to be adjusted to account for the difference in molecular weights. In the case of N2O, it has a molecular weight the same as CO2. Thus, one can use the mole-fraction directly, but they should be the same scale: That is, the relative effect of N2O:CO2 is 0.3:420 PPM. The nitrous oxide has an atmospheric abundance that is of the same order of magnitude as the uncertainty in the CO2 concentration measurements.
Except that the vast majority of CO2 is naturally occurring and we can’t do much about that
Hmmm . . . CO2 released from naturally-occurring forest fires compared to that from accidentally or intentionally (i.e., arsonist-originated) human-caused forest fires?
Admittedly, I don’t know where that ranks against “vast majority”.
As it happens, the same authors have exposed the Phony Nitrogen “Crisis” as a pretext for warring against farmers. The paper is Nitrous Oxide and Climate by C. A. de Lange, J. D. Ferguson, W. Happer, and W. A. van Wijngaarden.
https://arxiv.org/pdf/2211.15780.pdf
“Higher concentrations of atmospheric nitrous oxide (N2O) are expected to slightly warm Earth’s surface because of increases in radiative forcing. Radiative forcing is the difference in the net upward thermal radiation flux from the Earth through a transparent atmosphere and radiation through an otherwise identical atmosphere with greenhouse gases. Radiative forcing, normally measured in Wm−2, depends on latitude, longitude and altitude, but it is often quoted for the tropopause, about 11 km of altitude for temperate latitudes, or for the top of the atmosphere at around 90 km.
For current concentrations of greenhouse gases, the radiative forcing per added N2O molecule is about 230 times larger than the forcing per added carbon dioxide (CO2) molecule. This is due to the heavy saturation of the absorption band of the relatively abundant greenhouse gas, CO2, compared to the much smaller saturation of the absorption bands of the trace greenhouse gas N2O.
But the rate of increase of CO2 molecules, about 2.5 ppm/year (ppm = part per million by mole), is about 3000 times larger than increase of N2O molecules, which has held steady at around 0.00085 ppm/year since the year 1985. So, the contribution of nitrous oxide to the annual increase in forcing is 230/3000 or about 1/13 that of CO2. If the main greenhouse gases, CO2, CH4 and N2O have contributed about 0.1 C/decade of the warming observed over the past few decades, this would correspond to about 0.00064 K per year or 0.064 K per century of warming from N2O.”
“Proposals to place harsh restrictions on nitrous oxide emissions
because of warming fears are not justified by these facts.
Restrictions would cause serious harm;
for example, by jeopardizing world food supplies.”
My Synopsis:
https://rclutz.com/2023/11/15/phony-nitrogen-crisis-for-making-war-on-farmers/
…this would correspond to about 0.00064 K per year or 0.064 K per century of warming from N2O.”
______________________________________________________________________
And if anyone says it’s any more than that, they should pipe up and show their work or source.
We’ve had enough ‘piping up’ from Hunter Biden, thank you!
What I find most intriguing is that the earth completely shrugs off the effects of the solar luminosity variation, roughly equivalent to 15 years of global CO2 emissions. It’s a periodic variation, so signal processing techniques can be used very effectively here. Running an FFT on the data shows that there is essentially no change in the equilibrium temperature with a change in the downwelling radiation. I find this absolutely fascinating. The earth is controlling the energy imbalance, and CO2 apparently has nothing to do with it.
The ocean surface is limited to a sustainable 30C. Short term changes in ToA insolation over a few years makes very little difference to the area of ocean that reaches 30C.
But the long term increase in ToA peak solar intensity across the northern hemisphere is causing more ocean surface to reach 30C. The NH is warming up. The SH is so far only cooling south of 40S because regions north of that are still hitting the 30C limit.
Downwelling radiation enhances evaporative cooling whenever H2O molecules absorb the energy which is about 80% of the time. This removes energy from the surface. In addition, just about all the energy which reaches the surface is emitted just above the surface. It exists within the atmospheric boundary layer (ABL).
The ABL is always trying to establish equilibrium with the surface via conduction and the 2LOT. Any energy moved from the ABL to the surface creates an imbalance which is corrected by conduction. This returns the energy back to the ABL.
This eliminates any surface warming from downwelling IR but allows some cooling from evaporation and convection. The net effect of CO2 increases would be cooling except for the added absorption of 3 watt/s/m2 from the wings of CO2 absorption bands.
All put together we have no warming from CO2 increases but we should get a little more precipitation.
as expected, its a biggie…
(Composed in Word so shouldn’t have too many typos)
There are no perfect absorbers and no perfect emitters, as claimed.
i.e. If you want to vanish into minute trivia and details you do, making such an assumption is invalid.
It is stated that Ozone absorbs a lot of solar energy within the atmosphere but no mention of where the Ozone came from.
The Ozone comes from solar UV interacting with diatomic Oxygen – thus diatomic Oxygen is not transparent to solar energy.
It is stated that there is little Ozone near the surface.
Well why not? Because it is consumed by volatile organic compounds created by plants – how much solar energy do those gases absorb?
The explanation of the 2nd Law is beyond contrived and introduction of Entropy perfectly unnecessary – unless you don’t understand it.
Which you don’t hence all the tawdry and middling appeals to authority.
The 2nd Law simply states that heat energy always flows down a thermal gradient – NEVER the reverse.
So what do we read at the very top of Page 21 – as attached.
There are 2 massive errors there:
1/ The surface will always be warmer than anywhere above it in the atmosphere – heat energy can thus NOT flow in the direction stated. Radiation can, it can do as it likes. Radiation is NOT – energy.
Yes radiation can certainly come down to the surface from the sky/atmosphere/anywhere but if that sky/atmosphere/anywhere was colder than the point where it arrives, it will not be absorbed – THAT is = The 2nd Law.
Don’t confuse yourself with Entropy.
2/ It is confusing ‘radiation’ with ‘energy’. It is the exact same confusion endlessly seen between Watts and Watt-hours
i.e. The difference between energy and power
It all wraps up with its own real killer, a triumph of cause/effect muddlement:
1st para of Summary:”” Greenhouse gases warm the surface because they increase the “thermal resistance” of the atmosphere to the vertical flow of energy from the solar-heated surface to space.
As per the 2nd Law, greenhouse gases DO NOT warm the surface
That statement is deliberately misleading because it implies a positive heating effect.
The rest of the statement is true – yes green gases do increase the thermal resistance but any gas or any substance would do that. The arbitrary and contrived definition of green house gas is necessary.
So what this increase of thermal resistance does is reduce the rate of cooling but is only a valid concept when dealing with either or conduction or convection.
In fact great measure was made to rule out radiation as a source of this resistance when it was explained that radiation moves at ‘the speed of light’ – the thermal resistance is NOT a radiative effect.
That then means that the surface MUST somehow come to exist at a higher temp than it initially appears and that variations in the thermal resistance cause it to display the temperature it does.
But that means that the very initial premise of a temp of 278Kelvin for the surface must be wrong. (Minus 18 or minus 20 Celsius in most other pexplanations)
(Of course Tyndall would suggest green gases would warm the Earth – he was using boiling water in his experiment. He was actually recording that CO₂ was directly absorbing solar energy.)
Real experiment:
Visit the surface of the ocean on the equator and spend 24 hours there at the time of an equinox. Sit in a boat.
In fact, little of that is important, visit anywhere inside the tropics at almost any time.
Watch the sun rise fall disappear and rise again.
At solar noon you will record the power of the sun as being pretty dam close to 1,370Watts.
As it rose to that level and dropped away again, it will have followed a sine-curve, meaning that it’s root mean square average power was 1370 divided by sqrt(2) =869Watts
At night there is no sun so the average power you see over 24 hours is 484.5Watts
That sun is shining into deep clear water – presenting an albedo to normally incident sunlight of 0.06 meaning that the energy being absorbed becomes 457Watts
The emissivity of the liquid water will be about 0.95 (NOT = unity as assumed)
After millions of years to equilibrate, solar input will have come to equal radiated output which, using those figures according to Stefan will be= 303.5Kelvin or 30.5 Celsius = EXACTLY what is recorded
Then expand that calculation for up to 30 degrees of latitude gives an average and properly area-weighted temperature of 27.6Celsius for an area equal to 55% of Earth’s total surface area.
Worse: What really really is so mind blowing is the complete absence of Carnot in any of that. The fawning obsequience to the 1st Law is complete and absolute.
Because we are NEVER told what happens to ‘the radiation’ when it is being or has been absorbed.
Those interactions are in fact all = miniature Carnot Heat Engines and in the absence of a ‘perfect exhaust’ at Zero Kelvin, those engines are never 100% efficient.
And THAT is the explanation of the 2nd Law and is why, although the radiation ‘downwells’, the energy it carries from atmosphere to surface is never absorbed
To do so invokes a Heat Engine with negative efficiency = complete utter garbage
The atmosphere cools the surface.
Back to the drawing board people….
What is so pleasantly tickling while watching this muppetry, is the repeated mention of ‘Sahara Desert’ – as if it is is some monumental heirloom bequeathed to us from the engineers of The Big Bang.
There is completely NO WAY any theory of green gases can create that thing.
In any case, all substance are = Green House Substances, we know that from their colour.
Likewise, somewhere in there but my brain was hurting, was an involved, contrived and confabulated explanation of Stratosphere.
Stratosphere is simply the place where water freezes.
It really is a bummer also when your precious green gas stops Playing The Game isn’t it?
Even worse when CO₂ has perfectly immeasurable Emissivity (Read = zero as measured by No Mention Hottel in 1954
I agree with this. Any effort to explain Earth’s climate without getting into how convective instability occurs to drive Earth’s convective engine is missing the key atmospheric process.
That is true only for a particular point on the ocean’s surface, at an instant in time. Your generalization and extrapolation is not warranted. Actually, the specular reflectance for sea water with normal incidence is 0.021 (for green light). Additionally, there is a highly variable diffuse reflectance depending on the sediment and phytoplankton content, which varies seasonally and with proximity to the outlet of rivers, and results in an albedo > 0.021. However, the specular reflectance varies with the angle of incidence of the sunlight (and wave conditions), which varies with latitude and longitude for any instant in time. The proper way of handling this calculation requires a hemispherical integration of Fresnel’s Formula over the interval of time that the sun is illuminating a water surface.
For your assumption of “deep clear water,” the albedo will have a negligible contribution from suspended particles, and be dominated by the specular reflection, in part because the higher the angle of incidence, the less light that penetrates the water. We are talking about an average (green) specular reflectance (ignoring the small extinction coefficient) of about 0.122 for water over a nominal 12-hour period. The diffuse reflectance for sand and vegetation on land, which varies considerably with wavelength because plants absorb strongly at blue and red wavelengths, will vary with climate zone. An attempt at thematic classification of deserts with multispectral imagery, such as Landsat, will often result in creosote-dominated areas classifying as asphalt because of the large shadow component. On the other hand, tropical areas will have a high albedo — particularly in the near-IR wavelengths — because of all the leaves in the canopy.
I think that your attempt at a first-order approximation has value, but to be usable, you also have to demonstrate that a more refined approach gives essentially the same result. That way you can provide an estimate of the uncertainty of your simplified approach.
I enjoyed your post. It is a good example of how using averages just doesn’t explain what happens to the earth. Planck’s Theory of Heat Radiation deals with phenomena like smooth versus rough surfaces and how angles of incidence affect absorption. Nothing is so simple as to allow “accurate” use of average anything.
“Radiation is NOT – energy.”
Nonsense. If true, then explain how a microwave oven heats food.
I do love these discussions and I am always impressed by the quality of the commentary. There has been a long term question that I have been trying to get to the bottom of that I would like to pose here in the hope that it would generate some insight for us all. It is this:
“What is the relative contribution to the Earth’s temperature from greenhouse gases as compared to convective compression/expansion?”
Here is an article on the subject which strongly support the contention that the majority of the additional temperature increase on the Earth as compared to the airless moon is due to convective compression/expansion (i.e. the heat engine of the atmosphere driven by the sun’s heating of the surface). The main graph showing the fitting of the model to the relative atmospheric pressure vs. the solar constant for the planet in question is also attached below.
https://tallbloke.files.wordpress.com/2022/05/ecs_universal_equations-1.pdf
https://qph.cf2.quoracdn.net/main-qimg-88167ef94752773624c6d25a396b1f86
If I understand the mechanism of atmospheric convection and expansion/contraction that is driven by the convection, it is something like this:
1) The Sun heats the surface of the earth during the day (dominant heat source for the planet)
2) The atmosphere in contact with the surface is heated by direct contact with the warmer planetary surface
3) The warmer (less dense) air is bouyant against the rest of the atmosphere and rises (like a hot air balloon) and rises up from the surface expanding and cooling as it rises (cooling by expansion and by radiation to space and the surface)
4) Cooler air higher up in the atmosphere moves downward to replace the rising heated air and it is compressed by gravity as it moves downward and thus heats the air being compressed
5) although there is BOTH a heating and cooling effect going on at the same time (like a fridge), there is a net generation of extra heat because this “heat engine” is not 100% efficient at all.
6) Furthermore, the surface is heated more than the atmosphere higher up because the atmosphere is radiating at altitude to space and cooling as it rises
7) In addition at the rising thermals reach a certain altitude the entrained water vapor that has been evaporated by the surface heating generates clouds which form a white (reflective) surface for a reduction in albedo for that portion of the planet.
Now I realize that the mechanism of Greenhouse Warming and back radiation could ALSO play a role and I wonder if any of you have an estimate of the relative contribution of the two effects towards the surface temperature of the Earth (and Venus for example).
Any polite comments would be much appreciated!
Ian IN vancouver
Both radiative and convective mechanisms are discussed in the subject paper. I don’t recall the authors providing a clean split between the two effects, probably because convection doesn’t occur without the radiative effects of greenhouse gases.
thank-you Frank. What if the atmosphere had no Greenhouse Gases? I.e. A pure Nitrogen atmosphere still subject to convection?
According to the authors, no. In that case the project that the atmosphere would be isothermal at equilibrium.
That ignores any temperature gradient due to density changes. The lapse rate would still occur even in a pure N2/O2 atmosphere. The lapse rate has a gravity term for a reason.
thanks Jim. That is what I thought. Do you have any idea about the relative split between convective expansion/contraction vs. Greenhouse Gas warming for the Earth?
The atmospheric process works the same as a steam driven heat engine without the piston, valves and speed governor.
The profound feature of the atmosphere that enables the heat engine to work is the formation of the level of free convection. This occurs at an altitude where the adiabatic process that forms a stable lapse rate no longer applies. Radiation plays a role.
The zone above the level of free convection can dehumidify to create denser air that will sit stably on air that would normally be less dense if the atmosphere was unable to lose or gain heat, However the air at the LFC is being heated from radiation from below more than it is losing to space so it can become supersaturated and as dense as the dehumidified air.
So there is dense dry air sitting above a supersaturated layer supported by a near saturated, well mixed column below the LFC. The atmosphere has developed convective potential ripe for instability.
The instability is like the valve opening in a steam engine. Moist air is released into the dry air zone and rapidly expand. At surface temperature above 22C, the instability will be associated with cloudburst. Convective potential is ubiquitous across the tropical oceans – per attached.
Cloud burst over the tropics results in short lived cumulonimbus cloud but persistent cirrus cloud follows. In combination, the clouds regulate the surface sunlight such that the ocean surface temperature can never sustain more than 30C. The governor of the heat engine is the surface temperature regulation.
The tropical heat engines dominate the global air and ocean circulations. They also limit open ocean surface temperature to a sustainable 30C.
Climate models do not have the vertical resolution to determine the level of free convection so they end up with surface temperature disconnected from the cloud formation and produce stupid results like open ocean surfaces sustaining more than 30C.
“The profound feature of the atmosphere that enables the heat engine to work is the formation of the level of free convection. This occurs at an altitude where the adiabatic process that forms a stable lapse rate no longer applies.”
By “stable lapse rate” I presume you been one that is convectively stable. That is one where T diminishes with height less rapidly than the DALR (9.8 K/km). It’s true that if the rate were greater than that, there would be a heat engine. But with nothing to power it, all it would do is bring dT/dz back to the DALR. In any case tht does not happen. The gradient does not increase at the tropopause. It diminishes, even more quenching convection.
The atmospheric heat engine is literally powered by steam.
I will refer you to the radiosonde chart I attached below:
?fit=1212%2C854&ssl=1
You will observe in the chart, the environmental lapse rate is far from steady. The LFC at 2660m has CAPE of 1970J/kg above it. Note the large discontinuity in the gradient of the moisture profile (green line) at 700mb.
The convective instability is measured by the CAPE and is potential energy that will be extinguished by the expansion of moist air below the LFC into the dehumidified zone above the LFC. The creation of that instability and the extinction of the potential energy with latent heat as some of the water vapour condenses is the heat engine. All this happens in the troposphere well below the tropopause. The environmental lapse rate will approach the saturated lapse rate for the surface conditions immediately after instability. The column then starts to condense/solidifies from top down as the high altitude air radiates heat to space and the CAPE begins to reform.
A CAPE of 1970J/kg will produce an updraft of 62m/s. (225kph) so is a relatively powerful engine driving the local convection when it fires.
Dry air is more dense than moist air so a de-humidified zone sitting above a saturated zone creates potential energy – CAPE is an acronym for Convective Available Potential Energy. The dry air above the moist air is the piston of the heat engine. The LFC is the expansion nozzle.
The ability of the atmosphere to partition within the troposphere is a profound feature of Earth’s atmosphere and why Earth’s ocean surface temperature has an upper limit.
If it is a heat engine then it is certainly not 100% efficient. I.e. the movement of air must generate waste heat. Where does the heat of that inefficiency end up? Also, how much of that heat is there compared to the heat generated in the atmosphere by “Greenhouse Warming”??
Ian in Vancouver
If it is a heat engine then it is certainly not 100% efficient.
Correct. The mechanical work done in lifting the atmosphere is equal to the CAPE. That results in high velocity convective currents. The updraft velocity for CAPE in the example from the radiosonde is 62m/s.
Analysing the operation of the heat engine is not trivial. I have done the analysis for the tropical ocean regulating at 30C surface temperature. That is full power. In that case the power flux into the convective air motion averaged 58W/m^2. The surface solar insolation was 181W/m^2 and total insolation absorbed in the column and surface was 293W/m&2.
So the efficiency, taken as power input from the sun to produce the mechanical power in air movement is 58/293 = 19.7%. This figure overstates the mechanical efficiency because the tallest convective towers pull in latent heat from adjacent columns at mid level and release latent heat and sensible heat at high altitude. Through this process, the tallest towers have a net heat input and disrupt instability in columns over cooler water. With the data I have available, I cannot get a precise value for the net power gain but it is in the range of 7 to 24W/m^2. So if the upper value added to the insolation, then the mechanical efficiency drops to 18.2%.
Any ocean surface that is regulating to 30C will be producing at this power level driving global circulations. Cooler columns over oceans that experience instability will produce less power. Warmer columns that occur over land can produce much higher power level. CAPE can get above 4000J/kg so updraft would by 90m/s. This in when big hail stones can be formed.
Balloon data proves that the troposphere is always in thermodynamic equilibrium with a linear energy gradient.
https://youtu.be/XfRBr7PEawY?t=1431
I can’t see how CO2 can have any effect whatsoever.
It is just part of the atmosphere.
It doesn’t. This is what Miskolczi 2010 shows using the TIGR2 radiosonde data. The opacity of the atmosphere remains constant.
I will give it a C+. Mainly for a good attempt to show CO2 does little. But this statement in the conclusion is not accurate:
Any radiosonde over a surface above 22C with atmospheric water above 30mm will typically show a significant discontinuity in lapse rate per attached. The temperature profile is hardly steady gradient. Unless your model gets into how a level of free convection forms and convective potential develops, you are whistling dixie.
They have not determined the process that regulates Earth’s energy uptake and limits ocean surface temperature to 30C.
The paper does not get into cloud formation associated with convective instability. They do not get into partition into dehumidified and humidified zone that give rise to convective instability within the tropopause.
Convective instability is the profound process in Earth’s atmosphere. It is only studied in its relationship to damaging weather events but not the energy balance or climate. We have powerful convective storms that all have their origin in convective potential and no one is studying the key processes for the formation of convective potential.
Every single appreciable atmosphere over a rocky planet/moon that we can observe (13?) has a lower convective layer/layers with upper nonconvective layers – Earth has two sets. Each of these isothermal layers are due to some sort of absorption of intense solar radiation and act to block convection of the layer below it. This phenomenon occurs regardless of gas composition.
It’s all well over my head but that comment in the summary is pertinent as the usual estimate of climate sensitivity has been around 1C excluding feedbacks: “In the absence of feedbacks, the energy imbalance would eventually result in roughly 1 °C (1.8 °F) of global warming” (Wiki).
It’s a useful primer, but they get quite a lot wrong. From their bullet points starting at botom p 20:
“For a gray atmosphere, surface radiation to space is attenuated by factor e^−τ₀ where τ₀ is the vertical optical depth from the surface to outer space. Absorbed surface radiation is replaced by radiation emitted by greenhouse gases higher in the atmosphere.”
No, radiation attentaued is replaced by radiation from where is is absorbed. It has to be; there is no magic to transport the heat to those higher layers. Schwarzchiid got all that right a century ago.
“Radiative heat transport is negligible compared to convective heat transport below the tropopause.”
No, as they sort of explain, the atmosphere below the DALR (dry lapse rate) is convectively stable. Water vapor transports more heat, but less than radiative. See Trenberth’s observational heat budget.
“Without greenhouse gases, the adiabatic temperature profile of the troposphere would evolve into an isothermal profile with the same temperature as the surface.”
Definitely not. This was hashed out at least ten years ago. The forced motions of the air act as a heat pump, driving heat downwards. They more or less explain the mechanism, but miss the result. These motions are what forces the air temperature gradient toward the DALR. If the gradient goes beyond the DALR, the heat pump becomes a heat engine, and the atmosphere then is convectively unstable. Again this forces the temperature toward the DALR. None of this involves GHGs. The atmospheric motions result from temperature variations, eg latitude.
“Greenhouse gases increase the temperature of the surface, compared to the surface temperature in an atmosphere without greenhouse gases.”
Yes.
‘It’s a useful primer, but they get quite a lot wrong. From their bullet points starting at botom p 20:’
Nick,
That’s because at that point they’re describing a simplistic atmospheric model, akin to those used by alarmists to scare the bejesus out of sympathetic climate journalists.
Please read the remainder of the paper for a realistic description of the atmosphere that agrees very well with actual observations and demonstrates that further CO2 emissions will necessarily have a negligible impact.
“they’re describing a simplistic atmospheric model”
They don’t say that the listed are properties of that model. They say that they are:
“a number of important insights on how greenhouse gases work.”
And they are wrong.
“a realistic description of the atmosphere that agrees very well with actual observations”
They don’t give a description of the atmosphere at all. They show a number of IR spectra, similar to what Modtran would provide. And they don’t give any quantitative basis for CO2 sensitivity. They say they “estimate”. In fact they admit
“Increasing carbon dioxide will cause a small additional surface warming. It is difficult to calculate exactly how much, but our best estimate is that it is about 1 C for every doubling of CO2 concentration, when all feedbacks are correctly accounted for. “
In fact there are no feedbacks in their work.
I am going to make an observation that I think that your take is not exactly what the paper says. They are speaking of a model atmosphere that is not like the real atmosphere you are, perhaps, speaking of.
Darnit, I embedded some latex in order to make it more clear, but that didn’t work for some reason. At any rate, there is no doubt that a pencil of radiation originating at the surface (at a higher temperature than without GHG) will be attenuated by passing through the gray atmosphere. But at the emission height of this model atmosphere the outgoing radiation has to be the same as that which the surface would have emitted in the absense of greenhouse behavior. So, there must be a replacement of some of the outgoing surface radiation from atmosphere above the surface or “higher in the atmosphere” as they say.
How does this occur? Well, the atmosphere is convecting and maintaining its adiabatic temperature profile against radiative emission. So there is no “magic” as you say, but rather it is absorption, convection and then re-radiation accomplishing this moving of heat upward.
If in their example the optical depth is 5, then what results is a pretty savage attenuation by a factor of 0.007 or so, and the augmented surface temperature by a factor of 1.58 then has about 4.2% of the necessary equilibrium surface emission passing through the atmosphere. The other 95.8% comes from emission within the atmosphere higher than ground surface. It looks not unreasonable to me.
“but rather it is absorption, convection and then re-radiation”
So your magic is convection. But the atmosphere, with temp gradient less than DALR, is convectively stable. It just can’t do it. And the amount of convection would be massive, and is not observed. It would make flying aircraft very difficult.
You are ignoring the re-radiation…
I don’t think the amount of convection would be massive. It would only require being large enough to maintain a near adiabatic temperature profile in the presence of the constant absorption and re-emission through out the gray atmosphere.
“I don’t think the amount of convection would be massive.”
It must be. You have postulated rapid attenuation of the IR, If the convection is to then carry the main heat flux of about 240 W/m2, that is a lot of convection. Trenberth puts the observed convection at 15 W/m2.
In fact IR has been well measured at all levels of the atmosphere. The upward flux continues, and no replacing convection is observed.
Balloon analysis shows the energy gradient wrt density is as close to linear as you can get.
The gas laws are in control… that means convection, conduction, and other bulk air movements are constantly balancing the energy in the atmosphere.
Any pittance of weak, cold radiation from CO2 is basically a non-entity.
Would take anything Trenberth said with less than a grain of salt. !
I don’t know how many times this has to be said, but nothing I have said demands that convection do all the heavy lifting and I don’t think our authors are saying so either. You appear to be intent on insisting that the IR is all attenuated. It is not. A pencil of radiation starting at the surface and traveling to the TOA is greatly attenuated, but there is another contribution from the next infinitesimal dz above the surface, and more from the next dz above that and so on. By the time one reaches TOA the summation (integration) involves a large flux out.
The gray atmosphere is capable of conveying a large net flux upward on its own even if it is fairly thick. So 15 W/m2 might be all that is required of convection. Until we come up with a scenario and work it through we won’t actually know. I do know that combined radiation and convection transport problem are difficult to solve. So, you go first.
“So, you go first.”
Well, I think we are in the region where the Rosseland model comes close. Absorption is high, but local re-radiation balances it. The form of the result is a diffusion equation for heat, with still fairly high transmission. The key thing is that you don’t need, as W&H would have it, a magic mechanism to transport the heat to higher levels (convection?).
Why I keep resisting postulates of convection is that the air is convectively stable. That means that convection is actively suppressed. Any air that gets warm and rises cools faster than the rate at which the invironment is cooling with altitude. So it can’t get far. Trenberth’s 15% is made up of those parcels of air that warmed through differential surface temperature. Those differences can take the air only so far.
Besides, Nick, where have you observed a gray atmosphere?
Pretty grey here most of the day !
Clouds tend to do that. ! 🙂
droll.
“It would make flying aircraft very difficult.”
Seems Nick has never heard of turbulence, updrafts, and how gliders gain altitude.
Or why aircraft fly so high to avoid most of that turbulence.
Not only do they fly high to avoid most of that turbulence, but they go around it if at all possible. Seems pretty massive to me…
https://earth.nullschool.net/#current/wind/isobaric/1000hPa/overlay=mean_sea_level_pressure/orthographic=-69.72,-78.25,417
“Without greenhouse gases, the adiabatic temperature profile of the troposphere would evolve into an isothermal profile with the same temperature as the surface.”
Oh really? I’d like to see experimental support for the contention that a column of gas with a temperature differential magically becomes isothermal.
On the other hand – “Greenhouse gases increase the temperature of the surface, compared to the surface temperature in an atmosphere without greenhouse gases.”
Not on the Moon, obviously, and not according to experiments carried out by John Tyndall over 100 years ago.
To reiterate Feynman –
“It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong.”
Geez.
The parts in italics, which you have re-quoted, are from their paper.
Nick,
I know. Are you appealing to their authority?
Isothermal atmosphere? They are as wrong as you are. Speculation unsupported by observation or experiment.
Neither they nor you can actually describe the GHE.
Sad but true. You can always put me in my place by describing the GHE in some way that reflects reality. Only joking, of course you can’t.
‘Isothermal atmosphere? They are as wrong as you are. Speculation unsupported by observation or experiment.‘
So, exactly how does an atmosphere lacking GHGs, thereby completely transparent to LWR, thermalize?
“‘Isothermal atmosphere?” Nope… reality says!
Remove the main GHG, ie H2O, as in over a desert…
… and you get closer to the GRAVITY-based -9.8K/km rate.
H2O is the only substance that really changes that lase rate much at all.
CO2 certainly doesn’t.
You would think all of these people have never looked at the general equation for lapse rate. It does have a gravity term. The sensible heat shown in most radiation diagrams is due to conductive heating of the atmosphere. With these two factors, an isothermal atmosphere made up of non-absorbing and non-radiating noble gases would not exist.
I expect this conclusion arise due to what a simplified model uses as assumptions.
‘You would think all of these people have never looked at the general equation for lapse rate. It does have a gravity term.’
Jim,
With all due respect, so what? If the atmosphere doesn’t contain GHGs, it isn’t differentially heated or cooled by the absorbing or emitting of LWR. In the presence of gravity, this causes the atmosphere to convect.
Absent GHGs, LWR leaves the surface directly to space and the only heat transfer to the atmosphere itself is via conduction of heat from the surface. It’s a very slow process, but eventually the temperatures of the isothermal atmosphere and the surface will reach equilibrium.
Equilibrium in the real world is a convenient fiction.
At best, absent GHGs, the amplitude of variations is only reduced because there are still volcanic eruptions, wild fires, solar eclipses, variations in cloud albedo from unknown forcing agents, variations in coastal albedo from variations in river runoff, and possibly astronomical influences such as galactic dust.
The atmospheric density gradient allows the lower atmosphere to retain/hold more energy than higher in the atmosphere.
This will be the case no matter what the atmospheric composition.
So long as the planet surface is heated, an energy gradient will form.
‘Isothermal’ means the same temperature, not the same energy, for each atmospheric parcel regardless of density. Alarmists love it whenever skeptics try to refute the effect of GHGs by attributing the atmosphere’s temperature profile to compressional heating, a la pumping up a bicycle tire.
I’m confused. Are you saying that a planet warmed by the sun but without ”GHGs” would have a cold atmosphere?
I have thought about this some years ago, and I agree with this statement. Here is why.
In the atmosphere without greenhouse gases, besides the emitted power at the surface throught the transparent atmosphere, there is no heat transfer except at the interface between ground surface and atmosphere by conduction. A small amount of heat flows into the atmosphere and if great enough causes convection–if not by conduction. Convection moves heat energy upward and brings cooler air back the surface. There is continued heat transfer into the air. The process will continue as long as the ground surface is warmer than the air, it will only reach a steady state when the atmosphere is isothermal — even beyond the time when the atmosphere is stable against convection there will still be heat flow by conduction. Slow process? Yes, but we reach steady state in infinite time. The only steady state is isothermal.
I should have said for clarity and emphasis that “the only possible steady state is isothermal.”
“Convection moves heat energy upward and brings cooler air back the surface. “
There is nowhere for the heat to go, and no source of cooler air from above. But the thing is, if the air did rise, it would cool at the DALR, -9.8 K/km.
It is an odd statement for W et al to have made, because their own math explicitly sets out the true situation
The specify adiabatic and isotjermal, and as they say, adiabatic in the atmosphere is the same as isentropic. So in that formula, where s is entropy per mole, ds/dz is 0, and the temperature gradient must be the DALR. There is nothing about GHG here. Just thermo.
A clue here is the formula for L. m is molar mass, g gravity, c the specific heat and k the Boltzmann constant. There is no dependence on the radiative properties of the gas. It applies whatever they are.
Yes. The adiabatic lapse rate depends on convection. Radiation doesn’t produce a constant lapse rate. It produces a very different temperature profile if allowed to operate exclusively. When both processes operate what a person observes is different still.
The ultimate result is better described as steady-state rather than equilibrium. Stop thinking equilibrium thermo and please include non-equilibrium transport by multiple processes. Such problems are very difficult to solve.
‘There is nothing about GHG here. Just thermo.’
That’s because everything you quoted above is from the section of the article on ‘thermo’. They bring GHGs into the picture several sections / pages later.
Perhaps you don’t care for the way they structured their ‘primer’. However, it does makes you seem petty when you try to score points by finding ‘issues’ with incomplete models the authors use only to illustrate specific atmospheric phenomena.
It isn’t about a model. They are giving general theory in a section headed entropy. It’s an interesting scientific presentation.
But the key thing is that the lapse rate is what we observe in our real world. And it is given by those few parameters. If GHGs diminished or disappeared, the dry adiabatic lapse rate would still be -9.8 Z/km.
K/km
And ONLY H2O effects that lapse rate.
Nick has just destroyed the GHE conjecture ! 🙂
Well done Nick 🙂
Granted, but the absorption and re-emission keep the lapse rate away from dry adiabatic while convection, when initiated, seeks to move the profile back toward dry adiabatic. This is a transport problem that can’t be described entirely with an equilibrium thermodynamic result like the dry adiabitic lapse rate.
I am not sure your last sentence is correct. Taking out CO2 which reduces the Cp of dry air and leaving only N and O would put the Cp of dry air at about 1.03 as a guess. N Cp about 1.04 and O Cp about .92.
No, Nick. The source of cooler air is up at the upper boundary where radiation to space takes place. The difference between the upper boundary which radiates freely, and the lower boundary which absorbs freely but which has an actively re-emitting, warm atmosphere nearby is what organizes a net flux of radiation from ground to space in a process of continuous absorption and re-emission.
All I can say is that you keep reverting to our real atmosphere for data with which to pound away at a very interesting model. The comparison is not of pertinence. Your other issue is confusing equilibrium thermodyanamics with non-equilibrium transport phenomena.
“The source of cooler air is up at the upper boundary where radiation to space takes place.”
But you have posited no GHG. There is no such radiation.
Gotta’ knock this one down too. W&H posit a gray atmosphere. Even though this is an abstraction, it must possesses IR active gasses. Gray just means absorbs and emits all wavelengths of radiation equally. Maybe you confused one of their models (clear atmosphere) with next more complex model of a gray atmosphere.
possess not “possesses”
Kevin,
Here is what you said that I was responding to. It wasn’t about a gray atmosphere. It was explicitly about an atmpsphere without GHG:
“In the atmosphere without greenhouse gases, besides the emitted power at the surface throught the transparent atmosphere, there is no heat transfer except at the interface between ground surface and atmosphere by conduction. A small amount of heat flows into the atmosphere and if great enough causes convection–if not by conduction. Convection moves heat energy upward and brings cooler air back the surface. “
Nick, Convection moves heat energy upward and brings cooler air back the surface is what convection always does in gasses. I assumed in answering Mike Flynn that the non-greenhouse atmosphere starts in an arbitrary state and before it reaches a state of stability where it can no longer convect, then any rising parcel of air will be warmer on average than the rest of the atmosphere so cooler air will return to the surface. Eventually, when this atmosphere has become so uniformly warm that it cannot convect any longer, it will finish its march toward uniformity with diffusion (conduction). This is why I said “heat flows into the atmosphere and if great enough causes convection–if not by conduction.”
Not perhaps the best way to put it, and I mistook which model you were referring to, but what I said is still not wrong. The problem is that the thread constantly changes focus among multiple models in discussion, and four heat transfer mechanisms. It is detrimental to clarity.
However, I fail to understand your acrimony regarding this paper. I find it contains no more than a couple of statements that could have been made more clearly. It seems far better than your criticisms warrant and is a unique approach.
“your acrimony regarding this paper”
No acrimony. I said:
“It’s a useful primer, but they get quite a lot wrong.”
and I pointed out the things they got wrong. As I said, the paper has a lot of careful maths, settig the science out quite clearly. Then there are over-riding statements that are wrong, and often contradicted by the maths. I think that reflects the contributions of the different authos.
You may be pointing out things, but it isn’t they who are wrong. That would be you. Case in point:
I can continue to argue this forever if need be, but this posting appears to be nearly dead except for the occasional drive-by down voter.
Question, if as has been said here numerous times, all things emit based on their temperature then it can never been isothermal; Is that belief true?
In the specific case of this isothermal atmosphere the model can only absorb and radiate from the ground surface. The atmosphere has no radiation active gasses. So, the atmosphere continuous absorbs heat by thermal diffusion at the surface until its temperature is that of the surface. That is the end of the story. The steady-state. Isothermal.
A person has to be very careful about a blanket statement like “all thing emit based on temperature”. In the case of many metals they exhibit an IR emissivity approaching zero. So, even condensed matter doesn’t emit anything like the SB law would suggest.
N2 and O2 are responsible for about 2% of the LWR emissions of the atmosphere.
Your comment sent me off to investgate and well, the complications of real gasses are always interesting aren’t they? Van der Waals interactions between supposedly LWIR transparent diatomic molecules…
“Oh really? I’d like to see experimental support for the contention that a column of gas with a temperature differential magically becomes isothermal.”
In the situation they describe there is no mechanism for cooling at the top of the atmosphere.
Nick, this thread and comments are way beyond my knowledge base, but I do appreciate your critique.
I try to learn from your “nick-picks” and the responses.
My take at the end of these exchanges usually lands at –
“well, it seems that we just don’t yet know all the answers on this topic”
But please keep coming here and offering your takes.
WUWT is after all exemplified as not a “groupthink” site as are almost all the AGW proponent sites.
The stratosphere is the result of having free oxygen in the atmosphere. No other known planet has one.
99% of Venus’s atmospheric mass is in its troposphere, and then at the tropopause, it transitions to its mesosphere.
WRT adiabatic vs. isothermal equilibrium:
At the January 1862 meeting of the Manchester Literary and Philosophical Society, a paper, On the Convective Equilibrium of Temperature in the Atmosphere, by Professor Wm. Thomson was read by Dr. Joule:
“When all the parts of a fluid are freely interchanged and not subject to the influence of
radiation and conduction, the temperature of the fluid is said by the Author to be in a state of
convective equilibrium.”
In May 1866, J.C. Maxwell responds: On the Dynamical Theory of Gases, Philosophical Transactions
of the Royal Society of London, Vol. 157, p. 86 (1867),
“The left-hand side of equation (147), as sent to the Royal Society, contained a term, the
result of which was to indicate that a column of air, when itself, would assume a temperature
varying with the height, and greater above than below. The mistake arose from an error in
equation (143). Equation (147), as now corrected, shows that the flow of heat depends on the
variation of temperature only, and not on the direction of the variation of pressure. A vertical
column would therefore, when in thermal equilibrium, have the same temperature
throughout.”
In October 1875, Ludwig Boltzmann writes: Über das Wärmegleichgewicht von Gasen, auf welche
äußere Kräfte wirken, Sitzungsberichte der Mathematisch-Naturwissenschaftlichen, Vol. 72-II, p. 443
(1876),
“Aus dieser Formel folgt, daß trotz der Wirksamkeit der äußeren Kräfte für die Richtung der
Geschwindigkeit irgend eines der Moleküle jede Richtung im Raume gleich wahrscheinlich
ist, ferner dass in jedem Raumelemente des Gases die schwindigkeitsvertheilung des Gases
genau ebenso beschaffen ist, wie in einem Gase von gleicher Temperatur, auf das keine
Aussenkräfte wirken. Der Effect der äusseren Kräfte besteht blos darin, dass sich die Dichte
im Gase von Stelle zu Stelle verändert und zwar in einer Weise, welche schon aus der
Hydrostatik bekannt ist.”1
1. Google’s translation:
“From this formula, it follows that in spite of the effectiveness of the external forces for the direction of
the velocity of any of the molecules, each direction in space is equally probable, furthermore that in each space
element of the gas the velocity distribution of the gas is exactly the same as in a gas of same temperature, on
which no external forces act. The effect of the external forces consists merely in the fact that the density in the gas
changes from place to place in a manner which is already known from hydrostatics
As the upper troposphere is ALWAYS colder than the surface, it is impossible for any IR directed downward to warm the surface. The IR is reflected back upward and lost to space. Furthermore, none of these stupid models have night-time during which IR is poured out to space. That is why it chills down so quickly after sunset. This article is junk science as it adopts the idea of greenhouse gases. No gas at any concentration can warm the climate. And convection carries 85–90% of solar insolation energy to altitude where the energy is lost to space, including the latent heat of evaporation of convected water vapor as it condenses at altitude.
“As the upper troposphere is ALWAYS colder than the surface, it is impossible for any IR directed downward to warm the surface. The IR is reflected back upward and lost to space.”
By what mechanism is it reflected? If the surface can absorb that wavelength it will do so regardless of the temperature of the source.
” If the surface can absorb that wavelength it will do so regardless of the temperature of the source.”
Excellent statement. And the 2nd Law says nothing about such an event.
It needs some proof reading, makes some elementary mis-statements in the intro, e.g.:
“At sea level each molecule experiences a collision about once a nanosecond (a billion collisions per second).”
Actually more like 10 times/nsec.
“Although greenhouse gases do not scatter thermal radiation, they do emit it sponta- neously. So thermal radiation in opaque spectral regions is absorbed and independently reemitted as though it were being isotropically scattered.”
They do not emit ‘spontaneously’, the mean emission time is of the order of seconds so much longer than the collision time at atmospheric pressure so much of the absorbed energy is collisional transferred to the surrounding molecules.