The question—“Can you provide empirical measured proof of how much warming is caused by CO2?”—on its surface appears perfectly rational, even scientific. Yet, despite its appeal, it’s not just unanswerable with current methods—it also reflects a misunderstanding of how climate science works. And no matter one’s position in the climate debate, including those deeply skeptical of climate alarmism, it’s important to recognize why this question, as framed, is fundamentally flawed.
1. It Demands the Impossible: Controlled Experimentation on a Planetary Scale
The key issue is that it requests measured proof—in other words, direct empirical measurement of a variable in isolation. But Earth is not a laboratory. You can’t take one Earth, run it with 300 ppm CO₂, and another with 420 ppm, hold everything else constant (solar irradiance, ocean currents, volcanic activity, cloud cover, etc.), and then observe the difference in temperature.
Climate, by nature, is a complex, chaotic, coupled system. We can measure correlations, make inferences, and run models—but there is no laboratory setting where you can isolate CO₂ and “measure” its exact contribution to global mean surface temperature in the real world. Demanding that kind of empirical isolation is akin to asking for direct proof that one puff of a cigarette causes cancer—it’s an unreasonable standard for complex systems with multiple interacting variables.
2. Confuses Forcing with Attribution
CO₂ is a radiative forcing—an input to the climate system, not a direct output. What we do have, via satellite spectroscopy, are measurements showing CO₂ absorbing and re-emitting infrared radiation. We measure the “back radiation” impinging on ground stations. That’s measurable and uncontroversial. The effect size of this forcing, however, is not directly measurable in isolation. It is inferred through modeling and statistical attribution studies.
These studies attempt to assign fractions of observed warming to different causes—greenhouse gases, aerosols, solar variability, land use change, etc. They rely on climate models and statistical methods, not isolated laboratory measurements. So while you can ask how much warming is attributed to CO₂ based on models and assumptions, you cannot measure it directly.
For those chafing at the word “modeling“, it is through modeling that we convert satellite measurements of brightness into global temperatures. i.e. UAH 6.1.
3. It Plays Into the Hands of Alarmists by Oversimplifying the Debate
Ironically, asking for “measured proof” of CO₂-caused warming as a rhetorical trap often backfires. It allows climate activists to claim skeptics “don’t understand science” because, technically, the question is malformed. It allows them to redirect the conversation toward a debate about “settled science” at the molecular level (CO₂ absorbs infrared radiation), which is not where the real debate lies.
The serious skeptical position doesn’t hinge on denying radiative physics, but on questioning how much warming will result, how models perform, how feedbacks behave, how reliable the temperature record is, and most critically—whether climate policies based on uncertain projections make any sense. That’s where the fight should be, not on strawman arguments about measured proof.
4. It Obscures the Real Problem: Model Dependence and Feedback Assumptions
Even the IPCC doesn’t claim that the warming due to CO₂ can be directly measured. Instead, they use “attribution studies” based on model simulations. For instance, they simulate Earth’s climate with anthropogenic CO₂ and without it, and then compare the model runs to observed temperatures.
The result is a claim like “most of the observed warming since 1950 is very likely due to human activity”—but this is a model-based inference, not a measurement. The feedbacks assumed in these models (especially water vapor and clouds) are poorly understood, and small changes in those assumptions cause large swings in warming predictions.
A reasonable skeptic would focus here: not on denying that CO₂ is a greenhouse gas, but on highlighting the immense uncertainty in how much warming results from doubling CO₂ (climate sensitivity), which still ranges widely in the literature. That’s the intelligent battlefront—not a demand for something no one can provide.
5. It Encourages a Binary Thinking Trap
Skeptics often fall into a trap by arguing as if the entire climate narrative hinges on the CO₂ molecule being harmful. But even if CO₂ is warming the planet somewhat, the real debate is over magnitude, timing, impacts, and cost-benefit tradeoffs of climate policies.
Demanding measured proof of how much warming is caused by CO₂ invites a yes/no answer, when in reality the issue is one of probability distributions, confidence intervals, and uncertainty. This plays right into the absolutist thinking that dominates mainstream climate rhetoric.
Ask Smarter Questions—Because the Data Isn’t That Smart
Demanding measured proof of how much warming is caused by CO₂ is a rhetorical dead end—not because it’s unreasonable to seek evidence, but because it betrays a misunderstanding of what’s empirically measurable in a planetary climate system. The question collapses under its own demand for impossible precision in a noisy, chaotic, and multifactorial system.
A far more productive—and scientifically grounded—skepticism targets the soft underbelly of the climate consensus: the assumptions, uncertainties, and measurement issues underpinning the entire narrative.
Start with the temperature record itself. Long-term surface temperature series suffer from significant reliability issues. Stations have aged, moved, been surrounded by urban development, and upgraded with different instrumentation—all of which can introduce inhomogeneities and artificial trends. Adjustments to the raw data are often opaque and poorly justified, raising questions about how much warming is real versus “corrected” into existence.
Then there’s the far greater uncertainty in estimating global variables like ocean heat content—a metric central to claims of “unprecedented warming.” Before ARGO floats were deployed in the early 2000s, ocean temperatures were measured by a ragtag mix of ship intakes and bathythermographs, yielding sparse, uneven, and inconsistent data. Even now, ARGO floats only sample a small fraction of the ocean volume and don’t reach deep enough to detect long-term thermal trends with high confidence.
On top of this shaky empirical foundation, climate modelers layer their assumptions about radiative forcing, feedbacks, and cloud behavior to produce projections decades into the future—projections which have consistently overestimated warming in the short term.
So rather than asking for something that can’t be measured—like isolated proof of CO₂’s warming effect—skeptics should keep the focus on what can be measured, and on how poorly. Ask:
- How have the temperature data been adjusted, and what impact do those adjustments have?
- How sensitive are climate models to initial conditions and subjective parameter tuning?
- What are the error margins in ocean heat content estimates over time?
- Why do historical reconstructions rely so heavily on modeled reanalysis rather than direct observation?
- Are mitigation policies cost effective?
- What unintentional harm can be caused by mitigation policies.
- Why aren’t the benefits of increased CO₂ used in calculations of effects on society?
This is where honest, disciplined skepticism belongs—not in demanding a measurement that physics and Earth system complexity simply won’t allow, but in pointing out the wobbly scaffolding on which sweeping, costly policies are being erected, assumptions, uncertainties, and modeling limitations that underlie the entire edifice of climate policy. That’s where skepticism can be scientifically rigorous, effective, and intellectually honest.
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“What we do have, via satellite spectroscopy, are measurements showing CO₂ absorbing and re-emitting infrared radiation. We measure the “back radiation” impinging on ground stations.”
Curtis and Goody (1956) Thermal Radiation in the Upper Atmosphere discuss the decay rates of vibrationally excited CO2 (CO2*), following absorption of a 15u photon.
Radiative decay lifetime is 0.43 sec. In the lower troposphere at 220 K and 1 atm, collisional lifetime is 15 usec. This means, at the surface, CO2* decays by collision 28,667 times faster than it decays radiatively. This disparity in rates is not controversial.
At the surface, then, 99.997% of CO2* decays by collision. Not radiatively. Collisional decay transfers K.E. into the atmosphere. This is the GHE of CO2.
The question then is how the energetic water cycle of evaporation, convection, condensation responds. That response determines the effect of the extra K.E. on sensible temperature.
15u phonons deliver 7975.1 J/mole. At 288 K, the Boltzmann fraction of thermally excited CO2* is 3.6%. At 1 atm, 99.997% of thermally excited CO2* will decay by collision. Not radiatively.
The density of dry air (STP) is 1.29 kg/m^3. MW is 28.96 gm/mol.=> 44.96 mol/m^3 => 2.71E25 molecules/m^3.
Of these 420E-6 are CO2 => 1.14E21 molecules/m^3. Of these, if all become CO2*, 1.14E22 decay by collision – the same number as the total, at 2 sig figs past the decimal.
The 3.6% of CO2 thermally excited at 288 K is 4.10E20 molecules/m^3. Of these, 99.997% decay by collision at STP.
The radiative decay flux is 0.00035% of the thermally excited CO2* => 1.4E16 photons/sec/m^3. Half of this is “back radiation” namely, 7.1E15 photons/sec/m^3.
First order, the numbers scale with atmospheric pressure. The collision/radiative decay rate disparity also scales with atm. pressure.
Curtis & Goody note that the collision/radiative rate ratio = 1 at 74 km. Collisional decay severely dominates CO2* decay throughout the entire troposphere.
That’s it for “back radiation.” K.E. by radiative transfer from CO2* to the atmosphere is negligible. “Back radiation” contributes nothing to the GHE.
The 288 K atmosphere will generally maintain a thermal radiation bath of intensity set by that temperature. This bath radiation propagates randomly in all directions.
It seems likely that the IR detected and assigned to “back radiation” is just the thermal bath representing the 288 K thermal background IR.
I think this calculation is wrong. I believe the correct number is 0%. Once “thermally excited” a molecule must physically decide whether to keep the energy or not and where the energy gets located internally. The reason it will emit a photon is that it has no place to store the energy.
If a photon is needed to remove excess energy, there is no .43 second delay. The energy cannot exist in two places at once. The photon is emitted immediately and sent off in a random direction. The molecule itself cannot interact with another photon for .43 seconds but the energy from the collision is long gone.
This is different than the photon absorption case where the energy is immediately internalized. It must be immediate or it wouldn’t be available to pass on to other molecules in a collision.
Vibrationally excited CO2* doesn’t remember how it got there. Once there, the two decay rates are operative.
At 1 atm, collisional decay happens within about 15 usec; ~29,000 times faster than radiative decay. That’s the whole story.
Pat, you are a century or more out of date. “Collisional decay” sounds impressive but is misinformation. Atoms and molecules are not like little billiard balls bouncing around. This fixation with certain harmonic motions of CO2 is just pointless.
On a practical level, John Tyndall demonstrated that adding CO2 to air reduces the amount of radiation reaching an instrument, and it cools as a result. The hottest places on Earth have the least GHGs (Death Valley, Lut desert), as do the coldest (Antarctic plateau). Simple physics – no mythical GHE needed.
If you believe that adding CO2 to air makes it hotter, you are simply mistaken.
No,GHE.
Collisional decay of vibrationally excited CO2 is basic radiation physics. It doesn’t get “out of date.”
In fact, atoms, especially (e.g. Ar) and molecules do behave like frictionless billiard balls. Or is kinetic molecular theory out of date, too.
“Or is kinetic molecular theory out of date, too.”
Pretty much. It’s a simple model, good enough for the average student, to visualise macro processes. Until it falls down. Like Maxwell’s wave theory – excellent until it wasn’t.
Now, excited atoms or molecules don’t stay excited. They emit a photon, and revert to a lower unexcited state. It doesn’t matter, does it? Adding CO2 to air doesn’t make it hotter.
If you want to visualise atoms as little billiard balls, go for it. It still won’t support a silly notion like the GHE.
Kinetic molecular theory is basic statistical thermodynamics. Maxwell’s equations are standard practice in electrical engineering.
I’m not supporting AGW. My point is that radiation physics doesn’t support the idea of radiative transfer.
Pat,
Here’s something from SpringerNature link –
“Radiative transfer is the theory describing how electromagnetic radiation is transmitted through a medium such as a planetary atmosphere or a stellar photosphere. The medium can emit, absorb, and scatter radiation with a behavior that may vary strongly with wavelength according to the different species composing the medium and their physical state.”
I’m not sure what it is you don’t like about the “idea” of radiative transfer. I admit that “radiative transfer” looks like jargon which could easily be dispensed with. Just describe what happens, using the same terms used to describe “radiative transfer”. Why complicate things?
Maxwell’s equations are fine, but fail when considering phenomena like partial reflection, the photoelectric effect etc. Wave theory is excellent when photons act as waves, no good when they act as particles.
GHE enthusiasts sometimes seize on something they don’t understand clearly, and then try to make reality fit their misunderstanding. Hence, my asking GHE believers if they believe that adding CO2 to air makes it hotter. Easily disproved by experiment if they claim it does, and does away with nonsense about waves, particles, excitation, vibrations, and all the rest.
No offense intended, but if a thermometer shows an increase in temperature, I look for something hotter which is heating the thermometer. Not a popular hypothesis, apparently.
I still want to know how climate science separates the sun’s IR radiation from “back radiation” when measuring IR at the surface. Some of the “back radiation” even at night comes from the sun’s IR absorbed by the atmosphere during the day.
I should have written ‘doesn’t support radiative transfer as the dominant mode of energy transfer from vibrationally excited CO2 to atmospheric gases.’
The terrestrial atmosphere was the context, but I should have specified it.
Solar radiation is the source of surface heat. Water vapor makes the lower atmosphere warmer than it would be were the atmosphere dry and transparent to IR.
I am aware that Maxwell’s EM theory doesn’t explain quantum behavior.
It certainly doesn’t make the surface hotter. Read Tyndall or visit Death Valley if you don’t believe me.
Adding H2O to air doesn’t make it hotter. It doesn’t matter what you add, the atmosphere remains colder than the surface.
Even when the atmosphere is hotter than the surface (eg a low level nighttime inversion), the surface cools anyway. Semantic silliness doesn’t change facts.
No GHE, that’s why you can’t even find a consistent and unambiguous description anywhere at all.
Yet, Fresnel’s Equation, obtained from Maxwell’s Equation, handles reflection, transmission, and polarization with no problems that I’m aware of.
It doesn’t explain partial reflection. Would you mind addressing things I said, rather than things I didn’t? Maybe quoting what I said?
Boasting about problems of which you are not aware may not make you look more intelligent than you are.
Sir Isaac Newton was puzzled about partial reflection, knew of the wave theory of light, and realised that it could not explain partial reflection. Unfortunately, nor could Newton’s own corpuscular theory.
Your approach of completely ignoring reality is excellent, if you support silly notions like the indescribable GHE.
Adding CO2 to air does not make it hotter, but I’m sure you can ignore inconvenient facts if you try hard enough.
“Like Maxwell’s wave theory – excellent until it wasn’t.”
Maxwell’s equations work quite accurately until relativistic velocities are involved, just like Newton. Therefore still excellent for non-relativistic situations.
Think about what you just said. Within 15 µsec the energy from a photon is incorporated into a molecule. Since a photon is all energy, that means the photon no longer exists. Meanwhile, the molecule itself is unable to reemit this energy until full .43 seconds elapses. That sounds like the delay is due to the physics within the molecule.
You are claiming it takes 29,000 times longer for a molecule to emit a photon after a collision. Why would it take so much longer to emit a photon than to absorb one? Much more likely they are the same 15 µsec while the delay is again due to physics within the molecule.
I’m saying the “decay” time is actually the time the molecule itself takes before it can interact with another photon. The emission time is likely the same 15 µsec as the absorption time.
A photon is not a bullet so there isn’t any thing to disappear. A photon is a quanta of energy. It’s convenient to think of it as a bullet in order to conceptualize its particle characteristics. I like to think if it as a water balloon with no surrounding balloon. If someone drops that packet of water on you from a 100’ drop its going to sting but it isn’t a bullet. It just feels like one when it hits. The duality of a wave/particle in the quantum realm. The time a molecule takes to emit that packet if energy is a probability distribution just like everything in the quantum realm. 15 usec is just the point of highest probability. That distribution may be highly skewed, I haven’t researched it. Think of it as you eliminating that steak you ate last nite. When it actually comes out depends on a lot of things. You might be able to pinpoint a “usual” time but its not always going to be that time.
A photon is simply a nice way to express “quanta of energy”. It is something real and that something does disappear as the energy is incorporated into a molecule. That’s all I said.
No, that quanta of energy still exists just in a different form. Instead of being part of an EM wave it is part of the electron “wave” inside the molecule. The energy just changed form, it didn’t disappear. I would also note that quantum waves aren’t like waves on a lake.
Given an excited CO2 molecule, 15 µsec is the collisional energy transfer time. 0.43 sec is the radiative decay time.
In both cases, CO2 returns to the ground state.
See Curtis & Goody:
“The collisional relaxation lifetime for CO₂ in atmosphere of nitrogen at 220 K is about 15 microseconds. The radiative decay lifetime is 0.43 sec. For CO₂, the ratio of (radiative lifetime)/(collisional lifetime) = (lambda)/(phi) = 3.4×10-5 at 220 K and 1 atm pressure.
Page 199: “The height at which λ = φ is about 74 km.”
I didn’t question either one of those specifications. I’m looking at the radiative decay time in more detail. What does it really mean?
You are actually making assumptions which may be wrong by the way you are using this value.
‘I’m looking at the radiative decay time in more detail. What does it really mean?’
If I may, it’s a distribution, rather than a ‘fixed’ time period. The reason it’s important is because in the lower troposphere it’s very long compared to the time it takes for an excited GHG molecule to collide with a non-GHG molecule.
The attached essay (by Shula & Ott) from Andy May’s blog gives a good explanation for this process, as well as its implications for the GHE:
https://andymaypetrophysicist.com/wp-content/uploads/2025/01/Shula_Ott_Collaboration_Rev_5_Multipart_For_Wuwt_16jul2024.pdf
Yes, I’ve read their claims. The reason for my questioning Dr Frank is related. They treat absorptions and emissions differently.
1) In the case of absorption, they tell us this .43 second decay prevents reemission while not preventing collisional transfer of the absorbed energy. This is referred to as thermalization. Hence, the photonic energy must somehow be available to be transferred during a collision before the decay completes.
2) In the case of emission, they tell us collisions can again remove energy before the decay time completes which cancels the emission, hence CO2 emissions would be almost non-existent in the lower atmosphere.
In case 1) why would the energy be accessible before the decay time completes unless the physical absorption actually takes place immediately (~15 µsec)?
If case 1) description is correct, wouldn’t the photon already be non-existent? This means the actual energy transfer happens quickly and the decay time is due to something else.
3) If we apply this latest thought to case 2), that means the emission of a photon could also happen immediately (~15 µsec) and the energy would not be available to be removed by subsequent collisions. The decay time still occurs but is not related to when the photon is created.
Finally, 3) tells us the emissions as described by Shula/Ott/May would occur in the lower atmosphere negating the basis for many of their claims.
Let me take a stab at this:
1) You should review what they say here. My take is that at STP an excited GHG molecule is much more likely, on the order to 50K:1 to collide with another molecule than to spontaneously emit a photon. Upon collision, the vibrational energy of the GHG molecule is transferred to the kinetic energy of the other molecule, i.e., converted to sensible heat. At this point the photon is gone and is no longer ‘available’.
2) Keep in mind that thermalization doesn’t mean saturation. In fact, by returning GHG molecules back to their unexcited ground states, these molecules are now available to receive more photons from the surface or even from those relatively few photons (again, 50K:1) that are emitted spontaneously by excited GHG molecules that aren’t thermalized. Of course, once excited, these molecules are again much more likely to undergo thermalization than spontaneous emission.
Thermalization results in sensible heating of the lower troposphere which leads to convection. These warmed air parcels expand (do work) as they rise, meaning that the process is irreversible, i.e., the ‘flow’ of energy is upwards, albeit at a much slower rate than the thermal radiation that moves from the surface directly to space via the so-called atmospheric window.
One other idea to keep in mind is that ‘reverse thermalization’ or ‘thermally excited emission’ takes place, as well. In this process, the kinetic energy of a molecule that collides with a GHG molecule may boost the latter molecule into an excited state, from which it can spontaneously emit a photon. Less kinetic energy obviously cools the air aloft, which along with the aforementioned heating of the air near the surface is what drives convection. Tropospheric convection therefore results in an emissions ‘gradient’ where GHG molecules gradually become more likely to spontaneously emit photons at higher altitudes in the troposphere, as the air thins and collisions between molecules become relatively less common.
So, how do you explain the results of Feldman et al 2015? IR in the CO2 frequency bands is measured at an increasing rate following the concentration of CO2. This shouldn’t be possible if collisions are preventing the emission of photons by CO2 molecules low in the atmosphere.
Any photons generated higher in the atmosphere would be absorbed long before they reached the surface.
I would suggest this is experimental verification of my description. It is also falsification of the Shula/Ott theory.
Feldman et al demonstrated that they can reproduce a noisier version of the Keeling curve by using a different measured proxy for CO2 concentration. That is all.
Not sure what you mean. What is the proxy? If they are not measuring CO2 generated photons, what are they measuring?
They measured a time series of spectra using the AERI instrument over a period of several years at two locations. They subtracted a “model” baseline spectrum from each of these to measure the difference in the CO2 signal. From that, they interpolated the change in CO2 concentration which they charted as a “forcing.” The curves look like noisy Keeling curves (CO2 concentration measured at Mauna Loa.)
All they demonstrated was that they can measure the change in CO2 concentration in the atmosphere, albeit less accurately than the Mauna Loa observatory.
IMHO, it was dumb, ill-informed experiment and a waste of money.
‘So, how do you explain the results of Feldman et al 2015? IR in the CO2 frequency bands is measured at an increasing rate following the concentration of CO2. This shouldn’t be possible if collisions are preventing the emission of photons by CO2 molecules low in the atmosphere.’
For starters, 50K:1 doesn’t mean zero – it just means insignificant, the implication being that if the concentration of CO2 is increasing, then one would expect a commensurate increase in insignificant emissions in the proximity of their surface sensors, if indeed this is what they are actually measuring. And this, of course, does not in any way provide any evidence that the said ‘down-welling radiation’ (DLR) originated at higher levels of the troposphere.
Which brings me to my main point, which, as the article infers, DLR is not measured, but modeled. From your cited paper:
‘However, AERI spectral measurements and trends are sensitive to
many different components of the atmospheric state. To interpret these
measurements and attribute specific signals to rising CO2 requires an accurate radiative-transfer model that reproduces these spectra on the basis of an independent assessment of the state of the atmosphere. The model must capture instantaneous signals and long-term trends in the spectra to determine the effects of CO2 on diurnal to decadal timescales.’
In other words, what we know to be an inappropriate application of Schwarzschild’s radiative model to a convective troposphere is supposedly supported by invoking the same model to ‘prove’ its applicability. This is obviously either circular reasoning or yet another example of the special pleading that is commonly seen in consensus ‘climate science’.
What assumptions?
See my reply to Frank from NoVA.
In your 1), the 0.43 sec refers to mean radiative lifetime of the excited state. it does not refer to absorption.
Photons are energy (E=hv). A vibrationally excited CO2 is energetic. It carries the E=hv delivered by a photon.
Collision transfers that energy to N2 or O2 within a mean of 15 µsec, In N2 or O2 the transferred vibrational energy becomes translational energy,
Excited state decay can only happen after the excited state is produced by absorption of a photon. Absorption time is irrelevant to decay, or to which decay process occurs.
Energy is the unit of account. Not photons. When vibrationally excited CO2 decays radiatively, it does so by emitting a photon. The emitted photon is not “the same” photon that was absorbed, even though it is identical.
Your 2) is correct.
Your 3) is not correct. Emission of a photon from vibrationally excited CO2 takes a mean of 0.43 sec.
Collisional decay is so fast that decay by emission is rare throughout the troposphere.
Two problems with this claim. It appears to violate Kirchhoff’s Law of Radiation (emissivity => absorptivity) as well as Feldman et al 2015 results should be impossible.
Feldman measured DWIR at the surface in the CO2 bands at an increasing rate which followed nicely with the increased concentration of CO2. The only possible source for those emissions, tropospheric CO2, can’t emit IR based on your claim.
Read Curtis & Goody yourself, p. 1966 & 199.
For further discussion of Feldman 2015, see here and here.
I don’t have access to the C&G paper. The other discussions still don’t provide any definitive answer in understanding the correct view.
I understand there’s a delay related to EM radiation but that could be due to other factors and have nothing to do with the exact timing of photon interactions with a molecule.
The apparent violation of Kirchhoff’s Law is another red flag.
The view I have proposed seems more logical as well.
‘The apparent violation of Kirchhoff’s Law is another red flag.’
What apparent violation are you referring to?
Kirchhoff’s Law of Radiation specifics:
absorptivity <= emissivity
If CO2 cannot emit almost any energy low in the atmosphere yet can still absorb and thermalize energy, it’s pretty clear absorption would be significantly higher than emission.
My layman’s take on Kirchhoff’s Law(s) is that a good (bad) absorber of thermal radiation is a good (bad) emitter of thermal radiation. A slightly more technical description from Wikipedia is:
‘For an arbitrary body emitting and absorbing thermal radiation in thermodynamic equilibrium, the emissivity function is equal to the absorptivity function.’
Your objection on the basis of Kirchhoff’s Law is invalid because the requirement for thermodynamic equilibrium is clearly inapplicable to the ‘thick’ N2 / O2 lower troposphere where thermalization predominates.
I might also question if any of the properties of thermal radiation, which formerly were only extended to ‘bodies’ and ‘surfaces’, are actually applicable to gases, or whether this is something that has only come about in recent times to ‘justify’ a radiative-centric model for energy transfer that enable climate alarmism.
https://modern-physics.org/thermal-radiation-spectrum/
On average the atmosphere displays an approximate thermodynamic equilibrium. As a result Kirchhoff’s Law of Radiation should apply to the average.
Understand that gases are different than solids/liquids which is what you quoted. An individual molecule is always in thermodynamic equilibrium for the same reason it has no temperature.
On average? If you insist. Perhaps we can agree that in the lower troposphere, where thermalization predominates, absorption prevails over emission, in the upper troposphere, where reverse thermalization predominates, emission prevails over absorbtion and that somewhere in between, absorbtion and emission are in ‘equilibrium’.
p. 196: “The important factor in the equation of transfer is the ratio λ/φ which for both water vapour and carbon dioxide appears to be about 3.4 x 10^-5 at 220° K and 1 atm pressure. Deviations from the Boltzmann distribution will start to be important when this ratio is unity, i.e. at a pressure of about 34 dyn cm^~2 or a height of about 74 km, the uncertainty in this last figure being of the order of (+/-) 10 km.
The collisional relaxation lifetime for CO₂ in atmosphere of nitrogen at 220 K is about 15 microseconds. The radiative decay lifetime is 0.43 sec. For CO₂, the ratio of (radiative lifetime)/(collisional lifetime) = (lambda)/(phi) = 3.4×10-5 at 220 K and 1 atm pressure.
Page 199: “The height at which λ = φ is about 74 km.
p. 201: “For molecules such as carbon dioxide and ozone, with no permanent dipole moment, the rotational lifetime for spontaneous radiative transitions cannot be shorter than the vibrational, since such a transition cannot take place unless there is also a vibrational transition. For this type of molecule we require no further information about the spontaneous transitions.”
Thanks, Pat. I guess this leaves the issue open. The question in not whether the decay time is real. The question is exactly when does photon emission/absorption occur. From this it sounds like absorption and emission should be symmetric as they would be require a “vibrational transition”.
Am I reading this wrong?
Absorption occurs in approximately Planck time, following encounter of a CO2 with a resonant photon.
The photon field couples with the dipole of the C=O bond and the energy is absorbed. It becomes resident in the increased vibrational amplitude of the bond.
If the CO2* is undisturbed, emission will occur in a mean of 0.43 sec. A photon leaves, the CO2 returns to its ground state, and the vibrational amplitude returns to its original amplitude.
If, instead, the excited-state CO2* encounters an N2 or O2, the C=O bond vibrational energy transfers to the N2 or O2 as translational energy.
One can think of it as the vibrating bond giving the N2 or O2 a kick The C=O bond, having transferred its energy, settles down to its ground state amplitude, and the N2 or O2 rockets off.
That process occurs in a mean of 15 µsec at 1 atm.
Kirchoff’s Law applies to the undisturbed CO2, when absorption necessarily equals emission.
So, why won’t photon emission also occur in Planck time? I’ve seen nothing that requires the decay time of .43 seconds to equate to the exact time of emission after a collision. The decay time tells us when the molecule can once again couple with the EM field, not the exact time of emission.
If the transition has a certain half-width, ΔE, indicating an uncertainty in the transition energy, then the lifetime of the state, τ, is approximately
τ = ħ/ΔE, where ħ = (h/2π).
‘So, why won’t photon emission also occur in Planck time?’
Because statistically excited IR active gas molecules collide with non-IR active gas molecules well before they can spontaneously emit a photon.
‘I’ve seen nothing that requires the decay time of .43 seconds to equate to the exact time of emission after a collision.’
Again, that decay time refers to the half-life of a distribution, not an exact time of emission.
Early on you mentioned that you were skeptical that additional human emissions of CO2 would have much of an impact on climate. A very plausible reason for this, at least to some folks here, might be because near-surface thermalization of excited IR-active gas molecules leads to a very different explanation for energy transfer through the lower troposphere, relative to the radiative-only mechanism everyone is fed on a continual basis.
While there may be very valid reasons why this alternative explanation is partially or totally incorrect, I find it strange that many skeptics who take issue with it always fall back on the standard radiative explanation, meaning that they really do believe additional CO2 emissions will have an impact on climate.
Two possible causes of emission. I’m referring to emissions after a collision, not after absorbing a photon. I completely agree there’s a delay after photon absorption and the energy is likely thermalized before it can be reemitted.
What Shula/Ott claim, and you appear to support, is the same delay prevents emission after a molecule is excited due to a collision. This would mean almost no emissions at all in the troposphere.
I believe the .43 sec delay is too long of a time for a molecule to exist in an excited state with no place to put the energy from the collision.
BTW, CO2 molecules absorbing energy low in the atmosphere but never emitting any energy is likely to have a much stronger effect on the climate.
“the same delay prevents emission after a molecule is excited due to a collision”
An excited state has no memory of its origin. It’s the same state, no matter whether achieved by photon absorption or by collision.
“I believe the .43 sec delay is too long..”
Nevertheless, the radiative decay time is 0.43 sec. Note from C&G Table 6 that it’s been measured twice.
Note also the relatively long radiative decay times of water and ozone. Their energy transfer must primarily be by collision as well.
‘What Shula/Ott claim, and you appear to support, is the same delay prevents emission after a molecule is excited due to a collision. This would mean almost no emissions at all in the troposphere.’
No, if an IR active gas molecule at altitude is moved into an excited state by collision, it is very likely to emit a photon. You keep losing sight of the fact that there’s a gradient in the troposphere from where thermalization dominates near the surface to where reverse thermalization dominates near the tropopause.
‘BTW, CO2 molecules absorbing energy low in the atmosphere but never emitting any energy is likely to have a much stronger effect on the climate.’
Again, thermalization in the lower troposphere predominantly transfers energy in the form of sensible heat that is convected aloft.
According to Dr. Frank the altitude is 74 km, not at the top of the troposphere. Even then it is only a 50% chance of emission. That is 29,000 times less dense than the surface and the small number of GHGs could emit very little energy to space.
Why would convection increase? Convection is driven by temperature/pressure differences. The absorption would stay the same, very little energy would be emitted high in the atmosphere, so what would drive convection?
Sorry, I don’t buy it.
‘Convection is driven by temperature/pressure differences.’
Which are well explained by thermalization and warming near the Earth’s surface and reverse thermalization and cooling at altitude.
‘Sorry, I don’t buy it.’
And I no longer buy that you are in any way skeptical of the CAGW narrative given your unwillingness to either accept this or provide a better alternative.
I have provided an alternative many times in the past. The alternative works with accepted absorption/emission scenarios as supported by all radiation models while also agreeing with Kirchhoff’s Law of Radiation.
I accept almost all energy is thermalized low in the atmosphere. but rather than almost zero low atmospheric emissions, my view shows how emissions both cool the atmosphere and drive a reduction in high altitude water vapor (See Miskolczi 2023). The water vapor reduction balances the increase in CO2 absorption.
“CO2 molecules absorbing energy low in the atmosphere but never emitting any energy” never happens.
I’m just trying to understand the high probability situation. Something that happens .0003% of the time might as well be never when trying to understand energy flow.
From your graph water vapor would (almost) never be able to emit a photon low in the atmosphere either.
In addition, the entire atmosphere would not quickly start convecting more energy as convection is driven by temperature/density differences. With no radiative cooling low in the atmosphere, it would simply heat up more everywhere. The atmosphere couldn’t even warm the surface except by conduction.
This is almost like an atmosphere with no GHGs.
While more emissions would occur as you go up, it is still trivial until the density is so low not much energy would be emitted to space anyway. Since this is not what we see, it’s pretty obvious the view described here is missing something.
Excellent post!
Thanks. 🙂
‘At the surface, then, 99.997% of CO2* decays by collision. Not radiatively. Collisional decay transfers K.E. into the atmosphere. This is the GHE of CO2.’
Same process, similar numbers for H2O*.
‘The question then is how the energetic water cycle of evaporation, convection, condensation responds. That response determines the effect of the extra K.E. on sensible temperature.’
Good question. I don’t think the processes of ‘evaporation’, ‘convection’ and ‘condensation’ receive much consideration in most treatises on Earth’s energy balance, e.g., Trenberth et al (2009).
Like you, Frank, I look forward to the day when the field is again populated by climate physicists.
“Start with the temperature record itself. Long-term surface temperature series suffer from significant reliability issues. Stations have aged, moved, been surrounded by urban development, and upgraded with different instrumentation—all of which can introduce inhomogeneities and artificial trends.”
Whenever the difficulties associated with surface stations are listed here at WUWT, the impact of naturally ventilated screens on accuracy is ignored. It’s as though the idea just sails past consciousness.
Many field calibration experiments have been published. They invariably show that temperature sensors housed in naturally ventilated shields suffer seriously degraded accuracy by the thermal impact of uncontrolled environmental variables – primarily irradiance and insufficient wind speed.
Even radiance reflected at the screen from snow-covered ground can strongly impact Winter measurements. So does blown snow crusted into the louvers.
The sensor/screen installations used for field calibration experiments are perfectly sited and maintained. The field calibrations show that even under ideal conditions, the accuracy of a naturally ventilated land surface station is never better than (+/-)0.3 C.
And that’s not random error. It is systematic uncertainty and never goes away by averaging.
For LiG thermometers in a Stevenson screen (Cotton Region Shelter), systematic uncertainty is generally (+/-)0.5 C. The entire historical record to at least 2003, suffers from this limited accuracy.
The USCRN was set up in 2003, with its triple redundancy and mechanically ventilated shields. But even these suffer from self-heating error arising from their configuration.
None of this is ever included in WUWT appraisals of the land station record. I understand focus is on the results of the Surface Stations project, showing the very large siting problem.
But the inaccuracies from naturally ventilated shields is known, quantified, and very significant, and they should be included in accounts of surface station limitations.
In summary, the accuracy and precision reported for temperatures are greatly exaggerated.
+100
Some of us periodically point this out. The answer from the statisticians? LLN & CLT cancels all variability.
I understand the basic idea of attribution by running models with and without changes in CO2 concentration. But how about doing similar studies with and without variation in land use, clouds, ocean temperature cycles, solar insolation, and any other variables that could produce long term temperature trends? And how about various combinations of these? I suspect that the historical record of changes to these variables is simply insufficient and the models are inadequate for this purpose.
It’s my impression that the models were developed with an intense focus on trying to quantify the effects of human produced added CO2 while all other variables are held constant or “parameterized”. Seems like a huge exercise confirmation bias.
The unstated (and unexamined) assumption is that there is no co-correlation between CO2 and temperature, and the other variables that are being held ‘constant.’ I think that is unlikely. Inasmuch as plants are sinks for CO2, and are impacted by temperature and precipitation, I think it is obvious that there is co-correlation.
The problem is, where is the proof of the validity of the actual mechanism whereby increasing CO2’s share of the Standard Atmosphere absorbs enough energy at tropospheric pressures and temperatures to actually increase temperature? Where is that empirical data? Not the ‘climate science’ the actual physics and chemistry which prove what that mechanism is doing. It’s only been done inside a computer or in massively flawed sealed box experiments which ignore plain old Gas Law and do nothing more than prove how an actual greenhouse works… and you don’t need CO2 for that mechanism to function.
My best guess, but I’m an optics engineering guy so I work with radiation all the time but absorbing in solids. Have always ignored CO2 in any thermal radiation measuring system operating on samples warmer than -40°C. If temperature radiation measurement system works the same outside at 400ppmv as it does inside at 1,000ppmv+ that right there tells me it’s not a big driver otherwise we’d be seeing its shadowing effect. (Which is possible with methane cameras at way, way shorter wavelengths.)
Take a Standard Atmosphere mix of dry air with 400ppmv CO2 and a mass with 800ppmv and a lower molar concentration of O2 (since we are burning hydrocarbons.) Enclose in a broadband transparent sample container, controlled for constant pressure, monitor any volume changes, and expose them to the exact same radiation field from solar heated ground. To try and take the conduction transfer element out of the equation rework the mix with no CO2 and substitute N2O as it has an almost identical gas constant. I’m sure I’m missing something, but that should give you a much better idea if radiation alone is causing a temperature change while removing density/pressure increases which would not happen in the real world. They would be lost to convection and that absorbed energy dissipated as work against gravity.
In an ideal world you would sample with an FTIR spectroradiometer against a background at least -100°C to see if you got any additional radiation from the higher CO2 gas. Not sure how you pull that off and control the thermal noise. That’s the huge problem with CO2, its main lines are so weak it gets lost in the noise at NTP.
I personally have always had a huge problem with the incredibly low energy radiation in CO2’s emission/absorption spectra moving the peak of the Planck curve to the left. That whole ‘amplifying’ thing has never made sense either. Anyway… my 4 cents worth on a Saturday AM…
I would say that a large part of the warming over the last 40 years has been manmade. But not because of CO2, but rather because of the switch over from LIG temperature readings to electronic temperature readings.
Because with the studying l have been doing l have found that having electronic thermometers incased within small Stevenson screens is causing serious problems with there daytime temperature readings under certain weather conditions. Because whenever there is any extended periods of sunshine then the temperature readings are artificial high, due to the warming impact that the sunshine causes within the Stevenson screen. As the high sensitivity of electronic thermometers picks this up far more efficiently then LIG thermometers would.
The difference can be significant on cloudless sunny days with light winds.
With the difference in temperature readings between LIG thermometers in open shade and electronic thermometers in inclosed screens been as much as 4C.
With the current wide spread use of electronic thermometers taking temperature readings, there needs to be a major rethink in the design of the screens that are incasing these thermometers. As the current screens are not fit for purpose.
I am seriously looking at using soil temperatures as the metric that should be used for land-based temperature study. If CO2 is not a major absorber of SW radiation then the heat at 6′ is basically derived from the soil temperature through convection/conduction/radiation from the soil.
Yet I can find almost nothing from climate science addressing the relationship between soil temperature and the biosphere. Agricultural science has done some studies but they are generally very local in scope, primarily because of the lack of global data on soil temperature.
I haven’t found anything yet on how climate models handle the impact of soil temperature. I’m guessing they don’t address soil temps as a driver but, instead, focus solely on the assumption that GHG’s are the only driver of atmospheric temperature.
Once again the most simple explanation is the best one. Yes, the climate is complex but understanding that CO2 might not be the climate control knob in such a multifaceted system can not justify the $trillions being wasted on sunshine and breezes for what has every appearance of being an unworkable solution for a non-existing problem.
Meanwhile, this month’s call from the heavy power users conference in Houston, for a dramatic increase in nuclear power by 2050, suggests we may be moving on. We know the current DOE and Administation are listening, unlike what we’ve experienced for 12 of the past 16 years..
The only question that cuts wood is this: what is the optimum atmospheric concentration of CO2, that is at which the state of the atmosphere is optimally beneficial to mankind, the biosphere and the wider planet. Is it the pre-industrial concentration, or perhaps the one in 1950, or 2025, or the projected one in 2100? Nobody knows the answer (else we would learn of it in the news ad nauseam), so nobody on the planet knows whether the current concentration is too high, too low, or just right. And in the absence of such knowledge any statement about the effect of CO2 emissions is impossible.
One assumes there is no ‘optimum’ as it’s been all over the place since the first two chunks of matter stuck together in this orbit during this planet’s history. Arguably, the biggest driver of CO2 in the atmosphere is life itself showing up on the surface some 3.4gya as stromatolites, breaking it down for its carbon and ‘exhaling’ the poisonous, corrosive O2 the other soon to be introduced Kingdoms would need to live a productive life. The idea there is an ‘optimal’ anything when it comes to the Earth when planetary physics has had it whacked upside the equator with another whole planet, massively reheated and then had it traipse into ice ages likely baring no liquid water to the Heavens. I think ‘optimum’ is whatever it just happens to be today… and even that varies wildly depending on where and what part of the day you measure it.
Life does adapt to the prevailing conditions. That is why I suspect that the optimal pH range for calcifiers reflects the state of the oceans when a species first evolved. However, we are pretty sure from geological evidence that Hot House climate conditions are more conducive to the proliferation and evolution of life than are Ice House conditions, if for no other reason than chemical reactions proceed more rapidly under warm conditions than cold conditions. Not to mention it is almost impossible for plants to grow in ice, and without vegetation few higher life forms can survive.
All models are not created equal.
My criticisms on the Global Climate Models is they are unverifiable. The GCMs are highly speculative and contain many assumptions that are weakly supported, at best.
The climate models are opaque. Their inner workings are proprietary. It’s been reported elsewhere that models which don’t “predict” the desired outcome are discarded.
That is indeed the standard scientific approach and includes everything UAH puts forward. That the UAH (and satellites) would somehow be more accurate can only be substantiated by actual direct temperature measurements on surface level. Given the many anomalies in the way those are produced that increased accuracy can be questioned..
And that puts this article in perspective. That modeling argument is used by both climate alarmists and in this article..
And I’m not sure that all the assumptions are explicitly stated.
This reminds me of a question that I had for a socialist coworker of mine. I asked him, “We always get the claim that the ‘rich’ don’t pay their ‘fair share’. What is the exact number you think is right? What amount or percentage is fair?”.
His response: “I don’t care about ‘fair’, I just want more”.
They’ll say that any warming is too much, and/or claim that the bulk of it in recent decades is man-made. “Can you prove that we aren’t having any effect?” would be the predictable response.
Negatives are very hard to prove. If you find a dead Bigfoot and bring it in out of the wild for an autopsy, you have proven that they did exist, with the possibility of there still being more. Capture a live one, and you have proven that at least one still exists.
However, proving that they don’t exist is impossible. The best that one can hope for is a statistically based opinion, that after an exhaustive, lengthy, honest search and no incontrovertible evidence supporting the hypothesis has been produced, one can say that it is highly improbable that they exist. But that is not the same as proving that they don’t exist.
Clyde Spencer:
Earlier, I had proven that warming due to rising CO2 levels does not exist. Is this not the same as proving what you say is impossible?
I would be satisfied with anything that shows that catastrophic climate change isn’t happening, and that there is no existential threat, like the “extinction movement” or whatever they’re called is claiming. We have tons of evidence for that, but evidence, and even a hard proof, does no good when the other side ignores whatever they don’t like.
I think what we need is a Red and Blue team debate of the issues, moderated by a distinguished and well-respected emeritus professor — perhaps a Nobel Prize recipient — to rule on contentious points, to keep the debate moving along. The moderator should be someone well above the ‘pay grade’ of someone like Hansen or Mann, despite what their job titles may be.
“I think what we need is a Red and Blue team debate of the issues, . . . “
Debate? I think that all your “thoughts”, plus $5 cash, will buy you a $5 cup of coffee.
Facts are facts – regardless of what anybody “thinks”.
Adding CO2 to air does not make it hotter, no matter how many debaters employ semantic trickery to make it appear otherwise.
That’s reality.
Very good article, Charles.
Why make simple questions, complicated? Mainly, to confuse the issue.
Consider that the temperature of the Earth viewed from space is ~255K, compared to the mean surface temperature of ~285K. The 30K difference is labelled a “Greenhouse Effect“.
Even a third grader can appreciate that we NEED this temperature difference AND CO2 to live.
Next, consider that the mean surface temperature always has fluctuated on many time scales.
Finally, consider that the 1.5C limit to temperature increase set as the “tipping point” to disaster has been passed in both directions, repeatedly, in the past.
Meanwhile, we and our co-inhabitants of the Earth are still happily here.
Life has persisted for over 3.8 BILLION years even though the Sun’s heating has increased by 30%. I make no prediction about the future, but surely, we can enjoy the delightful “now”!
If it can’t be measured then it isn’t science, it’s philosophy.
Models don’t produce measurements, they exercise reasoning.
The thing that can be measured that we do care about is the impact of weather effects like rainfall, cyclones and crop yields.
As Charles says..
“The serious skeptical position doesn’t hinge on denying radiative physics, but on questioning how much warming will result…….then some other stuff..
I’ll repeat that part
“but on questioning how much warming will result”…
Can anyone tell us how much warming from CO2 there has been in the last 45 years ?
“Can anyone tell us how much warming from CO2 there has been in the last 45 years ?”
Yes. None at all. Nothing. Not even a tiny bit.
Thanks for finally agreeing that there is no measured evidence of CO2 warming 🙂
When the question is asked, the answer from any reasonable person should be…
“Sorry, I can’t provide any”!
Or look at the title of the article for your answer.
So you admit you can’t answer, this very reasonable question.
OK.
Just say so. !
You think the question is stupid.
I think your ducking and weaving is equally stupid..
I can explain it to you, and I did, but I can’t understand it for you.
Oh, I understand completely.
You cannot provide evidence for the contention that incremental CO2 causes warming…. period. !!
Why can’t you you just say there is no physical evidence.. and have done with it. ! ?
If there is no evidence that incremental atmospheric CO2 causes warming, then nothing that stems from that unproven conjecture has any point at all, and is just a waste of time.
Harold the Organic Chemist Says:
CO2 Does Not Cause Warming of Air!
Shown in the chart (See below) are plots of temperatures at the Furnace Creek weather station in Death Valley from 1922 to 2001. In 1922, the concentration of CO2 was ca. 303 ppmv (0.595 g of CO2/cu. m.), and by 2001, it had increased to ca. 371 ppmv (0.729 g of CO2/cu. m.), but there was no corresponding increase in the air temperature at this arid desert. The reason there was no increase in air temperature at this remote desert is quite simple: There is too little CO2 in the air.
At the MLO in Hawaii, the concentration of CO2 is 427 ppmv in dry air. One cubic meter of this air contains 0.839 g of CO2, a 15% increase since 2001, and has a mass of 1.29 kg at STP.
This small amount can heat up such a large mass of aIr by a very small amount if at all.
The above empirical temperature data show that the claim by the IPCC and the collaborating scientists that CO2 causes global warming is a fabrication and a deliberate lie.
NB: The chart of the Death Valley temperature plots was obtained from the late John Daly’s website: “Still Waiting For Greenhouse” available at www. John-Daly.com. From the home page scroll down to the end and click on “Station Temperature Data”. On the “World Map”, click on country or region to access the temperature chats from the weather stations located there. John Daly found ca 200 weather stations that showed no waring up to 2002.
“Why “Can you provide empirical measured proof of how much warming is caused by CO2?” is a really stupid question” is no answer, is it?
Is it really stupid to ask someone why they think adding CO2 to air makes it hotter?
If you equate “empirical measured proof” as meaningless jargon for “experimental support”, of course.
You cannot “prove” a speculation in science, and anyone demanding “proof” is just being silly, ignorant or both. “Disproof” on the other hand, is the basis of the scientific method. As Einstein said “No amount of experimentation can prove me right; a single experiment can prove me wrong.”
The problem with GHE supporters is that they refuse to provide a consistent and unambiguous description of the object of their worship, simply claiming that it is too sacred to be subjected to experiment. Or something like that.
People who realise that the GHE is a fantasy are not skeptics, they are realists. Nothing to be skeptical about – adding CO2 to air doesn’t make it hotter. Anybody who claims otherwise is dreaming.
Good post, Charles.
Nope, this is wrong. The average guy doesn’t give a damn about the difficulties you have mentioned. What he cares about is other people being in his pockets, restricting what he can drive, restricting how he heats or cools his house, forcing unreliable, intermittent, expensive renewable energy on him, endangering the grid with this worthless energy source and on and on. Think about it if you stayed out of his pockets and didn’t force useless inefficient mandates on him he wouldn’t give a damn what pseudo climate scientist did or thought. But that is not what is happening. These monsters are on a cult like crusade trying to convince us of current and future catastrophes caused by things they can’t measure and the things they can measure we can’t trust. Those guys can say what ever they want, they can lie and cheat, I don’t care but they need to keep their filthy hands out of my pockets and stop telling me what to do.
A nice article, but fundamentally wrong imo.
If you cannot do the experiment. you aren’t doing Science. QED. The problem with climate science is that we are not yet technologically sophisticated enough to draw certain conclusions.
The question is a valid one. The fact that it cannot be answered demonstrates that we are yet to be able to answer it, ie. our Science (modelling predominantly) isn’t up to it. THAT’S what has to change. It will, too. But it will take a long while yet an until validated, a GCM just provides political answers.
“but fundamentally wrong imo.”
“The question is a valid one.”
Thank you !! 🙂
I suggest that it is answerable and has in fact been answered. The “correct” answer according to 97% of scientists is “All of it”.
Of course, WUWT readers know this to be complete BS. That these claims are frequently and illegitimately presented as scientific fact needs to be challenged and challenged again.
“So rather than asking for something that can’t be measured . . . “, ask rather whether adding any amount of CO2 to air makes it hotter!
Easily measured, and the answer is a big fat zero!
Fiddling about with numbers is not experimentation. As Feynman said “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.” Sorry Charles, but if GHE believers try to get around the scientific method by claiming they can’t perform an experiment at all, then all their silly jargon like “radiative forcing” are just speculation – at best.
There is not even a consistent and unambiguous description of the so called “greenhouse effect”.
Removing GHGs from air increases the amount of solar radiation reaching the ground – increasing surface temperatures. Death Valley and the Lut desert spring to mind. And of course, because insulation works both ways, the coldest temperatures also occur where GHGs are least – the Antarctic plateau.
As Einstein said “No amount of experimentation can prove me right, a single experiment can prove me wrong”. GHE supporters have dreams and commitment, but no experiments to support their belief, nor any to show that people like myself are wrong.
No GHE. None, not even a tiny bit.
Someone once said that “there are no stupid questions, just stupid answers.”
Think about that. ! 😉
Great piece. I would never claim co2 isn’t a greenhouse gas or that there is no greenhouse effect. I would and do question how much, and the answer seems to be very little, good enough for me.
” It Demands the Impossible: Controlled Experimentation on a Planetary Scale”
Exactly, you realize that it CANNOT BE PROVEN. The point of the question is not to deny radiative physics. When I use that question, it is a lead in to a rhetorical trap about the certainty and consensus arguments. Instead it is, as you put it, to highlight “the immense uncertainty in how much warming results from doubling CO₂ (climate sensitivity)”. It sets a wonderful trap to lead them down the garden path of all the uncertainties and inferences that exist within the so called “settled science”.
EDIT: The reason that question is asked is precisely because we DO understand how “climate science” works, and that it doesn’t work well.
Charles said “Ask Smarter Questions—Because the Data Isn’t That Smart.”
You could always ask “Do you believe that adding CO2 to air makes it hotter, and why do you believe something so ridiculous?”
But why would you bother asking somebody so detached from reality, anything at all?
It’s not a stupid question if you know the people you ask cannot answer even while claiming it is known.
No, not stupid. “they” claim harm is caused. Force them to prove it. Make them slap their “proof” down on a table so EVERYONE can see it. If they can’t kick the living sh*t out of them.