There is an exciting new post on notrickszone.com here, that discusses a new paper on thermodynamics and the greenhouse effect. In addition to Gerlich and Tscheuschner and the new paper Hertzberg, et al. (2017), the recent paper Kramm and Dlugi (2011) is interesting.
Yes, indeed, all objects radiate energy if their temperature is above absolute zero. No question about it. But, if you place an object that is radiating at 101 degrees C next to an object radiating at 100 degrees C, they will both soon be radiating at 101 degrees C, not 201 degrees C. A cooler object cannot warm a warmer object, it does not happen, sorry. The second law of thermodynamics does apply.
“Thermodynamics is a funny subject. The first time you go through it, you don’t understand it at all. The second time you go through it, you think you understand it, except for one or two small points. The third time you go through it, you know you don’t understand it, but by that time you are so used to it, it doesn’t bother you any more. (Physicist Arnold Sommerfeld (1868-1951))”
“If we assume Earth is a blackbody, then subtract the solar energy reflected, from the hypothetically non-existent clouds, atmosphere, land, ice, and oceans; we can calculate a surface temperature of …”
The first climate entrepreneur to try the reductionist gambit of leaving “land , ice and oceans” out of the picture called the result of his ” sophisticated one dimensional model” “Nuclear Winter”
He was justly denounced as a charlatan by some few of Will Happer’s JASON colleagues.
The recrudescence of this sort of polemic here, in the climate wars of the 21st century, is redered all the more disgraceful , and ridiculous, by the author’s refusal to come to acknowledge or come to grips with two generations of progress in both atmospheric physics , computational hydrodynamics and the modeling of radiative transfer.
Will and Andy can go on turning to the right till the cows come home , but they’ll still be stuck at the bottom of a dry hole.
Russell, I think you missed my point. I was saying that the whole blackbody GHE calculation was absurd. In other words I agree with you.
Andy May wrote:
“Yes, indeed, all objects radiate energy if their temperature is above absolute zero.”
Absolutely not.
https://www.patriotaction.us/showthread.php?tid=2711
That statement applies to idealized blackbody objects, which emit if their temperature is greater than 0 K. It does not apply to real-world graybody objects, which only emit if their temperature is greater than 0 K above their ambient.
Whereas idealized blackbody objects maximally emit (and absorb), graybody objects emit (and absorb) in proportion to the energy density gradient.
You will note that idealized blackbody objects don’t actually exist… they’re idealizations. They are also provable contradictions which cannot physically exist, as I outline in my paper at the link above. The closest we can come are laboratory blackbodies which exhibit high absorptivity and emissivity at certain wavebands (but which still have thermal capacity and thus cannot be idealized blackbodies, which must emit all radiation they absorb by definition and thus can have no thermal capacity.).
There are two forms of the S-B equation:
https://web.archive.org/web/20211104195528if_/https://i.imgur.com/QErszYW.gif
[1] Idealized Blackbody Object form (assumes emission to 0 K and ε = 1 by definition):
q_bb = ε σ (T_h^4 – T_c^4)
= 1 σ (T_h^4 – 0 K)
= σ T^4
[2] Graybody Object form (assumes emission to > 0 K and ε < 1):
q_gb = ε σ (T_h^4 – T_c^4)
Climatologists misuse the S-B equation, using the idealized blackbody form of the equation upon real-world graybody objects. This essentially isolates each object into its own system so objects cannot interact via the ambient EM field, it assumes emission to 0 K, and it thus artificially inflates radiant exitance of all calculated-upon objects. Thus the climatologists must carry these incorrect values through their calculations and cancel them on the back end to get their equation to balance, subtracting a wholly-fictive 'cooler to warmer' energy flow from the real (but too high because it was calculated for emission to 0 K) ‘warmer to cooler’ energy flow.
That wholly-fictive ‘cooler to warmer’ energy flow is otherwise known as ‘backradiation’. It is nothing more than a mathematical artifact due to the misuse of the S-B equation. It does not and cannot exist. Its existence would imply rampant violations of the fundamental physical laws.
The S-B equation for graybody objects isn’t meant to be used by subtracting a wholly-fictive ‘cooler to warmer’ energy flow from the real (but too high because it was calculated for emission to 0 K) ‘warmer to cooler’ energy flow, it’s meant to be used by subtracting cooler object energy density from warmer object energy density to arrive at the energy density gradient, which determines radiant exitance of the warmer object. This is true even for the traditional form of the S-B equation, because temperature is a measure of radiation energy density, per Stefan’s Law.
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Temperature (T) is equal to the fourth root of radiation energy density (e) divided by Stefan’s Constant (a) (ie: the radiation constant), per Stefan’s Law.
e = T^4 a
a = 4σ/c
e = T^4 4σ/c
T^4 = e/(4σ/c)
T = 4^√(e/(4σ/c))
T = 4^√(e/a)
where:
a = 4σ/c = 7.5657332500339284719430800357226e-16 J m-3 K-4
where:
σ = (2 π^5 k_B^4) / (15 h^3 c^2) = 5.6703744191844294539709967318892308758401229702913e-8 W m-2 K-4
where:
σ = Stefan-Boltzmann Constant
k_B = Boltzmann Constant (1.380649e−23 J K−1)
h = Planck Constant (6.62607015e−34 J Hz−1)
c = light speed (299792458 m sec-1)
σ / a = 74948114.502437694376419756266673 W J-1 m (W m-2 / J m-3)
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The traditional Stefan-Boltzmann equation for graybody objects:
q = ε_h σ (T_h^4 – T_c^4)
[1] ∴ q = ε_h σ ((e_h / (4σ / c)) – (e_c / (4σ / c)))
Canceling units, we get J sec-1 m-2, which is W m-2 (1 J sec-1 = 1 W).
W m-2 = W m-2 K-4 * (Δ(J m-3 / (W m-2 K-4 / m sec-1)))
[2] ∴ q = (ε_h c (e_h – e_c)) / 4
Canceling units, we get J sec-1 m-2, which is W m-2 (1 J sec-1 = 1 W).
W m-2 = (m sec-1 (ΔJ m-3)) / 4
[3] ∴ q = (ε_h * (σ / a) * Δe)
Canceling units, we get W m-2.
W m-2 = ((W m-2 K-4 / J m-3 K-4) * ΔJ m-3)
One can see from the immediately-above equation that the Stefan-Boltzmann (S-B) equation for graybody objects is all about subtracting the energy density of the cooler object from the energy density of the warmer object.
You will note that σ = (a * c) / 4… the S-B Constant equals Stefan’s Constant multiplied by the speed of light in vacua divided by 4.
[4] ∴ q = (ε_h * ((a * c) / a) * Δe) / 4 = (ε_h * c * Δe) / 4
Canceling units, we get J sec-1 m-2, which is W m-2 (1 J sec-1 = 1 W).
W m-2 = (m sec-1 * ΔJ m-3) / 4
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The Stefan-Boltzmann equation in energy density form ([3] above):
σ / a * Δe * ε_h = W m-2
σ / a = 5.6703744191844294539709967318892308758401229702913e-8 W m-2 K-4 / 7.5657332500339284719430800357226e-16 J m-3 K-4 = 74948114.502437694376419756266673 W m-2 / J m-3.
Well, what do you know… that’s the conversion factor for radiant exitance (W m-2) and energy density (J m-3)!
It’s almost as if the radiant exitance of graybody objects is determined by the energy density gradient, right?
Energy can’t even spontaneously flow when there is zero energy density gradient:
σ [W m-2 K-4] / a [J m-3 K-4] * Δe [J m-3] * ε_h = [W m-2]
σ [W m-2 K-4] / a [J m-3 K-4] * 0 [J m-3] * ε_h = 0 [W m-2]
… it is certainly not going to spontaneously flow up an energy density gradient.
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Note 2LoT in the Clausius Statement sense:
“Heat can never pass from a colder to a warmer body without some other change, connected therewith, occurring at the same time.”
‘Heat’ is definitionally an energy flux, thus equivalently:
“Energy can never flow from a colder to a warmer body without some other change, connected therewith, occurring at the same time.”
That “some other change” typically being external energy doing work upon the system energy to pump it up the energy density gradient, which is what occurs in, for example, AC units and refrigerators.
Remember that temperature is a measure of energy density, equal to the fourth root of radiation energy density divided by Stefan’s Constant, per Stefan’s Law, thus equivalently:
“Energy can never flow from a lower to a higher energy density without some other change, connected therewith, occurring at the same time.”
Or, as I put it:
“Energy cannot spontaneously flow up an energy density gradient.”
My statement is merely a restatement of 2LoT in the Clausius Statement sense.
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Do remember that a warmer object will have higher energy density at all wavelengths than a cooler object:
https://web.archive.org/web/20240422125305if_/https://i.stack.imgur.com/qPJ94.png
… so there is no physical way possible by which energy can spontaneously flow from cooler (lower energy density) to warmer (higher energy density). ‘Backradiation’ is nothing more than a mathematical artifact due to the climatologists misusing the S-B equation.
The above completely destroys AGW and CAGW, because they are predicated upon the existence of “backradiation” (radiation spontaneously flowing up an energy density gradient) as the causative agent for the climatologists’ claimed “greenhouse effect”.
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The fact that energy cannot flow from a colder object to a warmer object, does not mean that the colder object does not emit energy.
Exactly.
When I’m laying in bed next to my gf, we both radiate heat towards each other, and our sides facing each other will gradually become warmer than the sides facing away from each other.
Neither of us will spontaneously stop emitting heat in one very particular direction the moment our partner becomes 1 degree warmer than the other.
The *net flow* will change if either of us changes temp, but that doesn’t mean that there’s no ‘back radiation’.
Similarly, in our atmosphere the net flow of energy will always be upwards towards colder space; doesn’t mean that reflectance/emissivity doesn’t alter the rate of energy flow and thus the temperature.