Guest essay by George White
For matter that’s absorbing and emitting energy, the emissions consequential to its temperature can be calculated exactly using the Stefan-Boltzmann Law,
1) P = εσT4
where P is the emissions in W/m2, T is the temperature of the emitting matter in degrees Kelvin, σ is the Stefan-Boltzmann constant whose value is about 5.67E-8 W/m2 per K4 and ε is the emissivity which is 1 for an ideal black body radiator and somewhere between 0 and 1 for a non ideal system also called a gray body. Wikipedia defines a Stefan-Boltzmann gray body as one “that does not absorb all incident radiation” although it doesn’t specify what happens to the unabsorbed energy which must either be reflected, passed through or do work other than heating the matter. This is a myopic view since the Stefan-Boltzmann Law is equally valid for quantifying a generalized gray body radiator whose source temperature is T and whose emissions are attenuated by an equivalent emissivity.
To conceptualize a gray body radiator, refer to Figure 1 which shows an ideal black body radiator whose emissions pass through a gray body filter where the emissions of the system are observed at the output of the filter. If T is the temperature of the black body, it’s also the temperature of the input to the gray body, thus Equation 1 still applies per Wikipedia’s over-constrained definition of a gray body. The emissivity then becomes the ratio between the energy flux on either side of the gray body filter. To be consistent with the Wikipedia definition, the path of the energy not being absorbed is omitted.
A key result is that for a system of radiating matter whose sole source of energy is that stored as its temperature, the only possible way to affect the relationship between its temperature and emissions is by varying ε since the exponent in T4 and σ are properties of immutable first principles physics and ε is the only free variable.
The units of emissions are Watt/meter2 and one Watt is one Joule per second. The climate system is linear to Joules meaning that if 1 Joule of photons arrives, 1 Joule of photons must leave and that each Joule of input contributes equally to the work done to sustain the average temperature independent of the frequency of the photons carrying that energy. This property of superposition in the energy domain is an important, unavoidable consequence of Conservation of Energy and often ignored.
The steady state condition for matter that’s both absorbing and emitting energy is that it must be receiving enough input energy to offset the emissions consequential to its temperature. If more arrives than is emitted, the temperature increases until the two are in balance. If less arrives, the temperature decreases until the input and output are again balanced. If the input goes to zero, T will decay to zero.
Since 1 calorie (4.18 Joules) increases the temperature of 1 gram of water by 1C, temperature is a linear metric of stored energy, however; owing to the T4 dependence of emissions, it’s a very non linear metric of radiated energy so while each degree of warmth requires the same incremental amount of stored energy, it requires an exponentially increasing incoming energy flux to keep from cooling.
The equilibrium climate sensitivity factor (hereafter called the sensitivity) is defined by the IPCC as the long term incremental increase in T given a 1 W/m2 increase in input, where incremental input is called forcing. This can be calculated for emitting matter in LTE by differentiating the Stefan-Boltzmann Law with respect to T and inverting the result. The value of dT/dP has the required units of degrees K per W/m2 and is the slope of the Stefan-Boltzmann relationship as a function of temperature given as,
2) dT/dP = (4εσT3)-1
A black body is nearly an exact model for the Moon. If P is the average energy flux density received from the Sun after reflection, the average temperature, T, and the sensitivity, dT/dP can be calculated exactly. If regions of the surface are analyzed independently, the average T and sensitivity for each region can be precisely determined. Due to the non linearity, it’s incorrect to sum up and average all the T’s for each region of the surface, but the power emitted by each region can be summed, averaged and converted into an equivalent average temperature by applying the Stefan-Boltzmann Law in reverse. Knowing the heat capacity per m2 of the surface, the dynamic response of the surface to the rising and setting Sun can also be calculated all of which was confirmed by equipment delivered to the Moon decades ago and more recently by the Lunar Reconnaissance Orbiter. Since the lunar surface in equilibrium with the Sun emits 1 W/m2 of emissions per W/m2 of power it receives, its surface power gain is 1.0. In an analytical sense, the surface power gain and surface sensitivity quantify the same thing, except for the units, where the power gain is dimensionless and independent of temperature, while the sensitivity as defined by the IPCC has a T-3 dependency and which is incorrectly considered to be approximately temperature independent.
A gray body emitter is one where the power emitted is less than would be expected for a black body at the same temperature. This is the only possibility since the emissivity can’t be greater than 1 without a source of power beyond the energy stored by the heated matter. The only place for the thermal energy to go, if not emitted, is back to the source and it’s this return of energy that manifests a temperature greater than the observable emissions suggest. The attenuation in output emissions may be spectrally uniform, spectrally specific or a combination of both and the equivalent emissivity is a scalar coefficient that embodies all possible attenuation components. Figure 2 illustrates how this is applied to Earth, where A represents the fraction of surface emissions absorbed by the atmosphere, (1 – A) is the fraction that passes through and the geometrical considerations for the difference between the area across which power is received by the atmosphere and the area across which power is emitted are accounted for. This leads to an emissivity for the gray body atmosphere of A and an effective emissivity for the system of (1 – A/2).
The average temperature of the Earth’s emitting surface at the bottom of the atmosphere is about 287K, has an emissivity very close to 1 and emits about 385 W/m2 per Equation 1. After accounting for reflection by the surface and clouds, the Earth receives about 240 W/m2 from the Sun, thus each W/m2 of input contributes equally to produce 1.6 W/m2 of surface emissions for a surface power gain of 1.6.
Two influences turn 240 W/m2 of solar input into 385 W/m2 of surface output. First is the effect of GHG’s which provides spectrally specific attenuation and second is the effect of the water in clouds which provides spectrally uniform attenuation. Both warm the surface by absorbing some fraction of surface emissions and after some delay, recycling about half of the energy back to the surface. Clouds also manifest a conditional cooling effect by increasing reflection unless the surface is covered in ice and snow when increasing clouds have only a warming influence.
Consider that if 290 W/m2 of the 385 W/m2 emitted by the surface is absorbed by atmospheric GHG’s and clouds (A ~ 0.75), the remaining 95 W/m2 passes directly into space. Atmospheric GHG’s and clouds absorb energy from the surface, while geometric considerations require the atmosphere to emit energy out to space and back to the surface in roughly equal proportions. Half of 290 W/m2 is 145 W/m2 which when added to the 95 W/m2 passed through the atmosphere exactly offsets the 240 W/m2 arriving from the Sun. When the remaining 145 W/m2 is added to the 240 W/m2 coming from the Sun, the total is 385 W/m2 exactly offsetting the 385 W/m2 emitted by the surface. If the atmosphere absorbed more than 290 W/m2, more than half of the absorbed energy would need to exit to space while less than half will be returned to the surface. If the atmosphere absorbed less, more than half must be returned to the surface and less would be sent into space. Given the geometric considerations of a gray body atmosphere and the measured effective emissivity of the system, the testable average fraction of surface emissions absorbed, A, can be predicted as,
3) A = 2(1 – ε)
Non radiant energy entering and leaving the atmosphere is not explicitly accounted for by the analysis, nor should it be, since only radiant energy transported by photons is relevant to the radiant balance and the corresponding sensitivity. Energy transported by matter includes convection and latent heat where the matter transporting energy can only be returned to the surface, primarily by weather. Whatever influences these have on the system are already accounted for by the LTE surface temperatures, thus their associated energies have a zero sum influence on the surface radiant emissions corresponding to its average temperature. Trenberth’s energy balance lumps the return of non radiant energy as part of the ‘back radiation’ term, which is technically incorrect since energy transported by matter is not radiation. To the extent that latent heat energy entering the atmosphere is radiated by clouds, less of the surface emissions absorbed by clouds must be emitted for balance. In LTE, clouds are both absorbing and emitting energy in equal amounts, thus any latent heat emitted into space is transient and will be offset by more surface energy being absorbed by atmospheric water.
The Earth can be accurately modeled as a black body surface with a gray body atmosphere, whose combination is a gray body emitter whose temperature is that of the surface and whose emissions are that of the planet. To complete the model, the required emissivity is about 0.62 which is the reciprocal of the surface power gain of 1.6 discussed earlier. Note that both values are dimensionless ratios with units of W/m2 per W/m2. Figure 3 demonstrates the predictive power of the simplest gray body model of the planet relative to satellite data.
Figure 3
Each little red dot is the average monthly emissions of the planet plotted against the average monthly surface temperature for each 2.5 degree slice of latitude. The larger dots are the averages for each slice across 3 decades of measurements. The data comes from the ISCCP cloud data set provided by GISS, although the output power had to be reconstructed from radiative transfer model driven by surface and cloud temperatures, cloud opacity and GHG concentrations, all of which were supplied variables. The green line is the Stefan-Boltzmann gray body model with an emissivity of 0.62 plotted to the same scale as the data. Even when compared against short term monthly averages, the data closely corresponds to the model. An even closer match to the data arises when the minor second order dependencies of the emissivity on temperature are accounted for,. The biggest of these is a small decrease in emissivity as temperatures increase above about 273K (0C). This is the result of water vapor becoming important and the lack of surface ice above 0C. Modifying the effective emissivity is exactly what changing CO2 concentrations would do, except to a much lesser extent, and the 3.7 W/m2 of forcing said to arise from doubling CO2 is the solar forcing equivalent to a slight decrease in emissivity keeping solar forcing constant.
Near the equator, the emissivity increases with temperature in one hemisphere with an offsetting decrease in the other. The origin of this is uncertain but it may be an anomaly that has to do with the normalization applied to use 1 AU solar data which can also explain some other minor anomalous differences seen between hemispheres in the ISCCP data, but that otherwise average out globally.
When calculating sensitivities using Equation 2, the result for the gray body model of the Earth is about 0.3K per W/m2 while that for an ideal black body (ε = 1) at the surface temperature would be about 0.19K per W/m2, both of which are illustrated in Figure 3. Modeling the planet as an ideal black body emitting 240 W/m2 results in an equivalent temperature of 255K and a sensitivity of about 0.27K per W/m2 which is the slope of the black curve and slightly less than the equivalent gray body sensitivity represented as a green line on the black curve.
This establishes theoretical possibilities for the planet’s sensitivity somewhere between 0.19K and 0.3K per W/m2 for a thermodynamic model of the planet that conforms to the requirements of the Stefan-Boltzmann Law. It’s important to recognize that the Stefan-Boltzmann Law is an uncontroversial and immutable law of physics, derivable from first principles, quantifies how matter emits energy, has been settled science for more than a century and has been experimentally validated innumerable times.
A problem arises with the stated sensitivity of 0.8C +/- 0.4C per W/m2, where even the so called high confidence lower limit of 0.4C per W/m2 is larger than any of the theoretical values. Figure 3 shows this as a blue line drawn to the same scale as the measured (red dots) and modeled (green line) data.
One rationalization arises by inferring a sensitivity from measurements of adjusted and homogenized surface temperature data, extrapolating a linear trend and considering that all change has been due to CO2 emissions. It’s clear that the temperature has increased since the end of the Little Ice Age, which coincidently was concurrent with increasing CO2 arising from the Industrial Revolution, and that this warming has been a little more than 1 degree C, for an average rate of about 0.5C per century. Much of this increase happened prior to the beginning the 20’th century and since then, the temperature has been fluctuating up and down and as recently as the 1970’s, many considered global cooling to be an imminent threat. Since the start of the 21’st century, the average temperature of the planet has remaining relatively constant, except for short term variability due to natural cycles like the PDO.
A serious problem is the assumption that all change is due to CO2 emissions when the ice core records show that change of this magnitude is quite normal and was so long before man harnessed fire when humanities primary influences on atmospheric CO2 was to breath and to decompose. The hypothesis that CO2 drives temperature arose as a knee jerk reaction to the Vostok ice cores which indicated a correlation between temperature and CO2 levels. While such a correlation is undeniable, newer, higher resolution data from the DomeC cores confirms an earlier temporal analysis of the Vostok data that showed how CO2 concentrations follow temperature changes by centuries and not the other way around as initially presumed. The most likely hypothesis explaining centuries of delay is biology where as the biosphere slowly adapts to warmer (colder) temperatures as more (less) land is suitable for biomass and the steady state CO2 concentrations will need to be more (less) in order to support a larger (smaller) biomass. The response is slow because it takes a while for natural sources of CO2 to arise and be accumulated by the biosphere. The variability of CO2 in the ice cores is really just a proxy for the size of the global biomass which happens to be temperature dependent.
The IPCC asserts that doubling CO2 is equivalent to 3.7 W/m2 of incremental, post albedo solar power and will result in a surface temperature increase of 3C based on a sensitivity of 0.8C per W/m2. An inconsistency arises because if the surface temperature increases by 3C, its emissions increase by more than 16 W/m2 so 3.7 W/m2 must be amplified by more than a factor of 4, rather than the factor of 1.6 measured for solar forcing. The explanation put forth is that the gain of 1.6 (equivalent to a sensitivity of about 0.3C per W/m2) is before feedback and that positive feedback amplifies this up to about 4.3 (0.8C per W/m2). This makes no sense whatsoever since the measured value of 1.6 W/m2 of surface emissions per W/m2 of solar input is a long term average and must already account for the net effects from all feedback like effects, positive, negative, known and unknown.
Another of the many problems with the feedback hypothesis is that the mapping to the feedback model used by climate science does not conform to two important assumptions that are crucial to Bode’s linear feedback amplifier analysis referenced to support the model. First is that the input and output must be linearly related to each other, while the forcing power input and temperature change output of the climate feedback model are not owing to the T4 relationship between the required input flux and temperature. The second is that Bode’s feedback model assumes an internal and infinite source of Joules powers the gain. The presumption that the Sun is this source is incorrect for if it was, the output power could never exceed the power supply and the surface power gain will never be more than 1 W/m2 of output per W/m2 of input which would limit the sensitivity to be less than 0.2C per W/m2.
Finally, much of the support for a high sensitivity comes from models. But as has been shown here, a simple gray body model predicts a much lower sensitivity and is based on nothing but the assumption that first principles physics must apply, moreover; there are no tuneable coefficients yet this model matches measurements far better than any other. The complex General Circulation Models used to predict weather are the foundation for models used to predict climate change. They do have physics within them, but also have many buried assumptions, knobs and dials that can be used to curve fit the model to arbitrary behavior. The knobs and dials are tweaked to match some short term trend, assuming it’s the result of CO2 emissions, and then extrapolated based on continuing a linear trend. The problem is that there as so many degrees of freedom in the model, it can be tuned to fit anything while remaining horribly deficient at both hindcasting and forecasting.
The results of this analysis explains the source of climate science skepticism, which is that IPCC driven climate science has no answer to the following question:
What law(s) of physics can explain how to override the requirements of the Stefan-Boltzmann Law as it applies to the sensitivity of matter absorbing and emitting energy, while also explaining why the data shows a nearly exact conformance to this law?
References
1) IPCC reports, definition of forcing, AR5, figure 8.1, AR5 Glossary, ‘climate sensitivity parameter’
2) Kevin E. Trenberth, John T. Fasullo, and Jeffrey Kiehl, 2009: Earth’s Global Energy Budget. Bull. Amer. Meteor. Soc., 90, 311–323.
3) Bode H, Network Analysis and Feedback Amplifier Design assumption of external power supply and linearity: first 2 paragraphs of the book
4) Manfred Mudelsee, The phase relations among atmospheric CO content, temperature and global ice volume over the past 420 ka, Quaternary Science Reviews 20 (2001) 583-589
5) Jouzel, J., et al. 2007: EPICA Dome C Ice Core 800KYr Deuterium Data and Temperature Estimates.
6) ISCCP Cloud Data Products: Rossow, W.B., and Schiffer, R.A., 1999: Advances in Understanding Clouds from ISCCP. Bull. Amer. Meteor. Soc., 80, 2261-2288.
7) “Diviner Lunar radiometer Experiment” UCLA, August, 2009
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“Trenberth’s energy balance lumps the return of non radiant energy as part of the ‘back radiation’ term, which is technically incorrect since energy transported by matter is not radiation.”
Trenberth shows the non radiant energy going out to space as radiation [ not “back radiating”]
Trenberth is simply getting the non radiant energy higher in the atmosphere where it eventually becomes radiative energy out to space [of course it does some back radiating itself as radiant energy but this part is included in his general back radiation schemata] . He is technically correct.
angech,
“He is technically correct.”
Latent heat cools the surface water as it evaporates and warms the droplet of water it condenses upon which returns to the surface as rain at a temperature warmer than it would be without the latent heat. The difference in what it would have been had all the latent heat been returned drives weather and is returned as gravitational potential energy (hydro electric power). The energy returned by the liquid water rain is not radiative, but nearly all the energy of that latent heat is returned to the surface as weather, including rain and the potential energy of liquid water lifted against gravity.
“Latent heat cools the surface water as it evaporates and warms the droplet of water it condenses upon which returns to the surface as rain at a temperature warmer than it would be without the latent heat.”
Where do you find such a description? Latent heat is released in order for water vapor to condense into liquid water again, and that heat is radiated away. Have you not noticed that water vapor condenses on cold surfaces, thus warming them? At the point of condensation the latent heat is lost from the now-liquid water, not when it strikes the earth again as rain.
Tom,
“… that heat is radiated away. ”
Where do you get this? How was water vapor radiate away latent heat? When vapor condenses, that heat is returns to the water is condenses upon and warms it. Little net energy is actually ‘radiated’ away from the condensing water since that atmospheric water is also absorbing new energy as it radiates stored energy consequential to its temperature. In LTE, absorption == emission and LTE sensitivity is all we care about.
This is quite pointless. Pick up a physics book, and figure out how the surface of water is cooled by evaporation: it is because in order for a molecule of water to leave the surface and become water vapor, it must have sufficient energy to break its bonds to the surface. This is what we call the heat of evaporation, or latent heat: water vapor contains more energy than liquid water at the same temperature. When water vapor condenses back into water, the energy that allowed it to become vapor is radiated away. It does not stay because… then the molecule would still be vapor.
Your avatar, co2isnotevil, I completely agree with. Where you got your information about thermal energy in the water cycle, or about the “temperature” of radiative energy, that I cannot guess. Not out of a Physics book. But I have seen similar errors among those who do not believe that radiative energy transactions in the atmosphere have any effect on the surface temperature at all, even when presented with evidence of that radiative flux striking the surface from the atmosphere above. And in that crowd, understanding of thermodynamics is sorely lacking.
Tom,
You didn’t answer my question. You assert that latent heat is somehow released into the atmosphere BEFORE the phase change. No physics text book will make this claim. I suggest that you perform this
experiment:
Now, why is the phase change from vapor to liquid any different, relative to where the heat ends up?
co2isnotevil wrote “You assert that latent heat is somehow released into the atmosphere BEFORE the phase change.”
That is incorrect. The phase change forces the release of the latent heat, which itself was captured at the point of escape from the liquid state. But of course, that’s not the only energy change a molecule of water vapor undergoes on its way from the surface liquid state it left behind to the liquid state it returned to at sufficient altitude: there are myriad collisions along the way, each capable of either raising or lowering the energy of that molecule, along with radiative energy transactions where the molecule can either gain or lose energy. But we are talking about the AVERAGE here, for that is what TEMPERATURE is: an average energy measurement of some number of molecules, none of which must be at that exact temperature state.
Your experiment shows nothing outrageous or unexpected: the latent heat of fusion (freezing) is 334 joules, or 79.7 calories, per gram of water, while it takes only 1 calorie to raise the temperature of one gram of water by 1 degree. Therefore, as the water freezes to ice, those ice molecules are shedding latent heat even without changing temperature, and the remaining water molecules — and the temperature probe as well as the container — were receiving that heat. Thermal conductivity slows the probe’s reaction to changes in environment, and your experiment no longer shows something unexpected. Only your interpretation is unexpected, frankly.
The heat of fusion is much smaller than the heat of vaporization, which is 2,230 joules, or 533 calories, per gram.
Latent heat is not magic, or even complicated. Water becoming water vapor chills the surface, the vapor carries the heat aloft, where it is released by the action of condensation. Any Physics text — or even “Science” books from elementary school curricula — will bear out this definition.
“Water becoming water vapor chills the surface, the vapor carries the heat aloft, where it is released by the action of condensation.”
I would say this,
Evaporation cools by taking energy from the shared electron cloud of the liquid water that’s evaporating, the vapor carries the latent heat aloft, where the action of condensation adds it to the energy of the shared electron cloud of the water droplet it condenses upon, warming it.
The water droplet collides with other similarly warmed water droplets (no net transfer here) and with colder gas molecules (small transfer here). Of course, any energy transferred to a gas molecule is unavailable for contributing to the radiative balance unless it’s returned back to some water capable of radiating it away.
The only part you got right: “the vapor carries the latent heat aloft”
“shared electron cloud” — you write as if you believe liquid water is one gigantic molecule.
You neglect the physics of collisions, and the pressure gradients of the atmosphere, and pretend latent heat all returns to earth in rain. Liquid water emits radiation, “co2isnotevil”. Surely you know this. That radiative emission spreads in all directions, with a large part of it escaping from space.
I’m done. I’ve already said this discussion is pointless, and I’ve wasted more than enough time. My physics books don’t read like you do; I’ll stick with them.
“you write as if you believe liquid water is one gigantic molecule.”
You’re being silly. But you do understand that the difference between a liquid and a gas is that the electrons clouds of individual molecules strongly interact, while in a gas, the only such interactions are elastic collisions where they never get within several molecular diameters of each other. This is also true for a solid, except that the molecules themselves are not free to move.
Think about how close together the molecules in water are. So much so that when it freezes into a solid, it expands.
Water vapour will condense under conditions of atmosphere cooler than it’s gaseous state. It most certainly not warm as a function of condensing. It will give up latent heat to sensible heat in the surrounding medium. This is generally at altitude where much of this heat will radiate away to space.
John,
“It will give up latent heat to sensible heat in the surrounding medium.”
The ‘medium’ is the water droplet that the vapor condenses on.
When water evaporates, it cools the water it evaporated from. When water freezes, the ice warms, just as when water condenses, the water it condenses upon warms. When ice melts, the surrounding ice cools. This is how salting a ski run works in the spring to solidify the snow.
The latent heat is not released until the phase change occurs, which is why it’s called ‘latent’.
What physical mechanism do you propose allows the latent heat to instantly heat the air around it when water vapor condenses?
“What physical mechanism do you propose allows the latent heat to instantly heat the air around it when water vapor condenses?”
The latent heat goes into the environment, bubble and air. On this scale, diffusion is fast. There is no unique destination for it. Your notion that the drops somehow retain the heat and return it to the surface just won’t work. The rain is not hot. Drops quickly equilibrate to the temperature of the surrounding air. On a small scale, radiation is insignificant for heat transfer compared to conduction.
Condensation often occurs in the context of updraft. Air is cooling adiabatically (pressure drop), and the LH just goes into slowing the cooling.
“Your notion that the drops somehow retain the heat and return it to the surface just won’t work.”
Did you watch or do the experiment?
You’re claiming diffusion, but that requires collisions between water droplets and since you do not believe the heat is retained by the water, how can diffusion work?
The latent heat per H2O molecule is about 1.5E-19 joules. The energy of a 10u photons (middle of LWIR range of emissions) is about 2E-20 joules. Are you trying to say that upon condensation, at many LWIR photons are instantly released? Alternatively, the kinetic energy of an N2 or O2 molecule in motion at 343 m/sec is about 2.7E-20 joules, so are you trying to say that the velocity of the closest air molecule more than doubles? What laws of physics do you suggest explains this?
How does this energy leave the condensed water so quickly? And BTW, the latent heat of evaporation doesn’t even show up until the vapor condenses on a water droplet, so whatever its disposition, it starts in the condensing water.
“The complex General Circulation Models used to predict weather are the foundation for models used to predict climate change. They do have physics within them, but also have many buried assumptions, knobs and dials that can be used to curve fit the model to arbitrary behavior. The knobs and dials are tweaked to match some short term trend, assuming it’s the result of CO2 emissions, and then extrapolated based on continuing a linear trend. The problem is that there as so many degrees of freedom in the model, it can be tuned to fit anything while remaining horribly deficient at both hind casting and forecasting.”
Spot on.
I think the stuff about the simple grey body model contains some good ideas on energy balance but needs to be put together in a better way without the blanket statements.
“The Earth can be accurately modeled as a black body surface with a gray body atmosphere, whose combination is a gray body emitter whose temperature is that of the surface and whose emissions are that of the planet. ”
Accurate modelling is not possible with such a complex structure though well described.
“Accurate modelling is not possible with such a complex structure though well described.”
Unless it matches the data which Figure 3 tests and undeniably confirms the prediction of this model. As I also pointed out, I’ve been able to model the temperature dependence of the emissivity and the model matches the data even better. How else can you explain Figure 3?
Models are only approximations anyway and the point is that this approximation, as simple as it is, has remarkable predictive power, including predicting what the sensitivity must be.
The GCMs do not actually forecast. They equivocate, which is not the same concept.
Hah! It’s forecasting without all that silly accountability!
Right!
When we remember that radiant energy is only a result of heat/temperature/ kinetic vibration rates in EM Fields, not a cause; we can start to avoid the tail-chasing waste of time that is modern climate ‘science’. When? Soon please.
Can you actually use the Stefan-Boltzmann Law to something like Earth’s atmosphere which is never constant, its composition continually changes not least because of changes in water vapour and the composition of gases with respect to altitude?,
Richard Verney
“Can you actually use the Stefan-Boltzmann Law to something like Earth’s atmosphere”
It’s a good question, not so much about the constancy issues, but just applying to a gas. S-B applies to emission from surface of opaque solid or liquid. For gases, it is more complicated. Each volume emits an amount of radiation proportional to its mass and emissivity properties of the gas, which are very frequency-banded. There is also absorption. But there is a T^4 dependence on temperature as well.
I find a useful picture is this. For absorption at a particular frequency a gas can be thought of as a whole collection of little black balls. The density and absorption cross-section (absorptivity) determine how much is absorbed, and leads in effect to Beer’s Law. For emission, the same; the balls are now emitting according to the real Beer’s Law.
Looking down where the cross-sections are high, you can’t see the Earth’s surface. You see in effect a black body made of balls. But they aren’t all at the same temperature. The optical depth measures how far you can see into them. If it’s low, the temperature probably is much the same. Then all the variations you speak of don’t matter so much.
Thanks.
That was partly what I had in mind when raising the question, but you have probably better expressed it than I would have.
I am going to reflect upon insight of your second and third paragraphs.
Richard,
Gases are simple. O2 and N2 are transparent to visible light and LWIR radiation, so relative to the radiative balance, they are completely invisible. Most of the radiation emitted by the atmosphere comes from the water in clouds which is a BB radiator. GHG’s are just omnidirectional, narrow band emitters and relative to equivalent temperature, Joules of photons are Joules of photons, independent of wavelength. The only important concept is the steradian component of emissions which is a property of EM radiation, not black or gray bodies.
“For emission, the same; the balls are now emitting according to the real Beer’s Law.”
Oops, I meant the real Stefan-Boltzmann law.
co2isnotevil,
“Most of the radiation emitted by the atmosphere comes from the water in clouds which is a BB radiator. GHG’s are just omnidirectional, narrow band emitters and relative to equivalent temperature, Joules of photons are Joules of photons, independent of wavelength.”
The directional aspects of water droplet reflection interest me, in that the shape of very small droplets is dominated by surface tension forces, which means they are spherical . . which means (to this ignorant soul) that those droplets ought to be especially reflective straight back in the direction in the light arrives from, rather than simply skittering the light, owing to their physical shape.
This hypothetical behavior might have ramifications, particularly in the realms of cloud/mist albedo, I feel, but your discussion here makes me wonder if it might have ramifications in terms of “focused” directional “down-welling” radiation as well, as in the warmed surface being effectively mirrored by moisture in the atmosphere above it . .
Pleas make me sane, if I’m drifting into crazyville here ; )
John,
Wouldn’t gravity drive water droplets into tear drop shapes, rather than spheres? Certainly rain is heavy enough that surface tension does not keep the drops spherical, especially in the presence of wind.
Water drops both absorb and reflect photons of light and LWIR, but other droplets are moving around so it doesn’t bounce back to the original source, but off some other drop that passed by and so on and so forth. Basic scattering.
co2isnotevil.
“Wouldn’t gravity drive water droplets into tear drop shapes, rather than spheres?”
When they are large (and falling) sure, but most are not so large, of course. I did some investigating, and it seems very small droplets are dominated by surface tension forces and are generally quite spherical.
“Water drops both absorb and reflect photons of light and LWIR. . ”
That’s key to the questions I’m pondering now, the LWIR. Some years ago I “discovered” that highway line paint is reflective because tiny glass beads are mixed into it, and the beads tend to reflect light right back at the source (headlights in this case). I’ve never seen any discussion about the potential for spherical water droplets to preferentially reflect directly back at the source, rather than full scattering. It may be nothing, but I suspect there may be a small directionality effect that is being overlooked . . Thanks for the kind response.
As rel humidity goes to nearly 100% outgoing radiation drops by about 2/3rds, one good possibility is fog that is effective in LWIR, but outside the 8-14u window because it and optical are still clear. This or both co2 and WV both start to radiate and start exchanging photons back and forth. But it drops based on dew point temperature.
Thanks, micro, that’s some fascinating detail to consider . .
Richard,
Unless the planet and atmosphere is not comprised of matter, the SB law will apply in the aggregate. People get confused by being ‘inside’ the atmosphere, rather than observing it from a far. We are really talking about 2 different things here though. The SB law converts between energy and equivalent temperature. The steradian component of where radiation is going is common to all omnidirectional emittersm broad band (Planck) or narrow band emitters (line emissions).
The SB law is applied because climate science is stuck in the temperature domain and the metric of sensitivity used is temperature as a function of radiation. What’s conserved is energy, not temperature and this disconnect interferes with understanding the system.
The Earth/atmosphere system is a grey body for the period of time it takes for the first cycle of atmospheric convective overturning to take place.
During that first cycle less energy is being emitted than is being received because a portion of the surface energy is being conducted to the atmosphere and convected upward thereby converting kinetic energy (heat) to potential energy (not heat).
Once the first convective overturning cycle completes then potential energy is being converted to kinetic energy in descent at the same rate as kinetic energy is being converted to potential energy in ascent and the system stabilises with the atmosphere entering hydrostatic equilibrium.
Once at hydrostatic equilibrium the system then becomes a blackbody which satisfies the S-B equation provided it is observed from outside the atmosphere.
Meanwhile the surface temperature beneath the convecting atmosphere must be above the temperature predicted by S-B because extra kinetic energy is needed at the surface to support continuing convective overturning.
That scenario appears to satisfy all the basic points made in George White’s head post.
“What law(s) of physics can explain how to override the requirements of the Stefan-Boltzmann Law as it applies to the sensitivity of matter absorbing and emitting energy, while also explaining why the data shows a nearly exact conformance to this law?”
The conditions that must apply for the S-B equation to apply are specific:
“Quantitatively, emissivity is the ratio of the thermal radiation from a surface to the radiation from an ideal black surface at the same temperature as given by the Stefan–Boltzmann law. The ratio varies from 0 to 1”
From here:
https://en.wikipedia.org/wiki/Emissivity
and:
“The Stefan–Boltzmann law describes the power radiated from a black body in terms of its temperature. Specifically, the Stefan–Boltzmann law states that the total energy radiated per unit surface area of a black body across all wavelengths per unit time (also known as the black-body radiant emittance or radiant exitance), , is directly proportional to the fourth power of the black body’s thermodynamic temperature T:”
In summary, when a planetary surface is subjected to insolation the surface temperature will rise to a point where energy out will match energy absorbed. That is a solely radiative relationship where no other energy transmission modes are involved.
For an ideal black surface the ratio of energy out to energy in is 1 (as much goes out as comes in) which is often referred to as ‘unity’. The temperature of the body must rise until 1 obtains.
For a non-ideal black surface there is some leeway to account for conduction into and out of the surface such that where there is emission of less than unity the body is more properly described as a greybody. For example an emissivity of 0.9 but for rocky planets such processes are minimal and unity is quickly gained for little change in surface temperature which is why the S-B equation gives a good approximation of the surface temperature to be expected.
Where all incoming radiation is reflected straight out again without absorption then that is known as a whitebody
During the very first convective overturning cycle a planet with an atmosphere is not an ideal blackbody because the process of conduction and convection draws energy upward and away from the surface. As above, the surface temperature drops from 255K to 222K. The rate of emission during the first convective cycle is less than unity so at that point the planet is a greybody. The planet substantially ceases to meet the blackbody approximation implicit in the requirements of the S-B equation.
Due to the time taken by convective overturning in transferring energy from the illuminated side to the dark side (the greybody period) the lowered emissivity during the first convective cycle causes an accumulation within the atmosphere of a far larger amount of conducted and convected energy than that small amount of surface conduction involved with a rocky surface in the absence of a convecting atmosphere and so for a planet with an atmosphere the S-B equation becomes far less reliable as an indicator of surface temperature. In fact, the more massive the atmosphere the less reliable the S-B equation becomes.
For the thermal effect of a more massive atmosphere see here:
http://onlinelibrary.wiley.com/doi/10.1002/2016GL071279/abstract
“We find that higher atmospheric mass tends to increase the near-surface
temperature mostly due to an increase in the heat capacity of the
atmosphere, which decreases the net radiative cooling effect in the lower
layers of the atmosphere. Additionally, the vertical advection of heat by
eddies decreases with increasing atmospheric mass, resulting in further
near-surface warming.”
At the end of the first convective cycle there is no longer any energy being drawn from the incoming radiation because, instead, the energy required for the next convective cycle is coming via advection from the unilluminated side. At that point the planet reverts to being a blackbody once more and unity is regained with energy out equalling energy in.
But, the dark side is 33K less cold than it otherwise would have been and the illuminated side is 33K warmer than it should be at unity. The subsequent complex interaction of radiative and non- radiative energy flows within the atmosphere does not need to be considered at this stage.
The S-B equation being purely radiative has failed to account for surface kinetic energy engaged in non-radiative energy exchanges between the surface and the top of the atmosphere.
The S-B equation does not deal with that scenario so it would appear that AGW theory is applying that equation incorrectly.
It is the incorrect application of the S-B equation that has led AGW proponents to propose a surface warming effect from DWIR within the atmosphere so as to compensate for the missing non-radiative surface warming effect of descending air that is omitted from their energy budget. That is the only way they can appear to balance the budget without taking into account the separate non-radiative energy loop that is involved in conduction and convection.
I really don’t think that
“The Earth can be accurately modeled as a black body surface with a gray body atmosphere”
This is utterly inaccurate because of the massive energy flux between those, that make them behave as a single thing : the tiny pellicle of the whole Earth, which also include ocean water a few meter deep, and other thing such like forests and human building. This pellicle may seem huge and apt to be separated in components from our human very small scale, but from a Stefan-Boltzmann Law perspective this shouldn’t be done.
AND
remember that photosynthesis has a magnitude ( ~5% of incoming energy) greater than that of the so called “forcing” or other variations. It just cannot be ignored… but it is !
paqyfelyc,
“The Earth can be accurately modeled as a black body surface with a gray body atmosphere”
Then what is your explanation for Figure 3? Keep in mind that the behavior in Figure 3 was predicted by the model. This is just an application of the scientific method where predictions are made and then tested.
Photosynthesis is a process of conversion of electromagnetic energy to chemical potential energy. In total and over time, all energy fixed by photosynthesis is given up and goes back to space. Photosynthesis may retain some energy on the surface for a time but that energy is not thermal and has virtually no effect on temperature.
John,
“This is utterly inaccurate because of the massive energy flux between those”
The net flux passing from the surface to the atmosphere is about 385 W/m^2 corresponding the the average temperature of about 287K. Latent heat, thermals and any non photon transport of energy is a zero sum influence on the surface. The only effect any of this has is on the surface temperature and the surface temperature adjusted by all these factors is the temperature of the emitting body.
Trenberth messed this up big time which has confused skeptics and warmists alike by the conflating energy transported by photons with the energy transported by matter when the energy transported by matter is a zero sum flux at the surface. What he did was lump the return of energy transported by matter (weather, rain, wind, etc) as ‘back radiation’ when non of these are actually radiative. As best I can tell, he did this because it made the GHG effect look much larger than it really is.
” … warm the surface by absorbing some fraction of surface emissions and after some delay, recycling about half of the energy back to the surface.”
Ahhh, there’s the magic! The surface warms itself.
Are the laws of physics suspended during the “delay”? What’s causing the delay?
What is the duration of the delay since those emissions are travelling at the speed of light?
What’s the temperature delta of the surface between the emission and when it’s own energy is recycled back?
If the delay and the delta are each insignificant, then the entire effect is insignificant.
Thomas,
“What’s causing the delay?”
The speed of light. For photons that pass directly from the surface to space, this time is very short. For photons absorbed and re-emitted by GHG’s (or clouds), the path the energy takes is not a straight line and takes longer, moreover; the energy is temporally stored as either the energy of a state transition, or energy contributing to the temperature of liquid or solid water in clouds.
co2isnotevil replied below with: “For photons absorbed and re-emitted by GHG’s (or clouds), the path the energy takes is not a straight line and takes longer”
I’m asking how much longer, twice as long? Show me where and how long the duration is of any significant delay. Is it the same order of magnitude as the amount of time a room full of mirrors stays lit after turning out the lights? IOW, insignificant?
Now, instead of considering these emissions as a set of photons, consider them as a relentless wave and you’ll see there is no significant delay.
“I’m asking how much longer”
At 1 ns per foot, it takes on the order of a milisecond for a photon to pass directly from the surface to space. Photons delayed by GHG absorption/re-emission will take on the order of seconds to as much as a minute. Photons of energy delayed by being absorbed by the water in clouds before being re-emitted is delayed on the order of minutes. It’s this delayed energy distributed over time and returned to the surface that combines with incident solar energy and contributes to GHG/cloud warming which of course is limited by the absorption of prior emissions.
The delay doesn’t need to be long, just non zero in order for ‘old energy’ from prior surface emissions to be combined with ‘new energy’ from the Sun.
But the sun does not shine at night (over half the planet).
That is one of the facts that the K&T energy budget cartoon (whatever it should be called)fails to note.
Richard,
“But the sun does not shine at night (over half the planet).”
This is one of the factors of 2 in the factor of 4 between incident solar energy and average incident energy. The other factor of 2 comes from distributing solar energy arriving in a plane across a curved surface whose surface area is twice as large. Of course, we can also consider the factor of 4 to be the ratio between the surface area of a sphere and the area that solar energy arrives from the Sun, half of this sphere is in darkness at all times.
The Earth spins fast enough and the atmosphere smooths out night and day temps, so this is a reasonable thing to do relative to establishing an average. Planets tidal locked to its energy source (for example Mercury), would only divide the incident power by 2.
[ co2isnotevil –
“Photons of energy delayed by being absorbed by the water in clouds before being re-emitted is delayed on the order of minutes” ]
Order of minutes? So, the laws of physics are being suspended then.
A photon can bounce from the surface up to 40 Kilometers and back 3200 times per second if it were reflected without delay. And your claim is that it is delayed an order of minutes? I find that extremely doubtful. The transfer of heat is relentless. Do all of those photons take a vacation in the clouds?
But my question also asked what the surface temperature delta is for the duration of your claimed delay. I’ll give you two minutes, what is the temperature delta in two minutes? That vacationing photon was emitted from the surface at some temperature, what is the surface temperature when it returns to the surface? Has it lost more energy than the surface during its vacation in the clouds?
[ co2isnotevil –
“The delay doesn’t need to be long, just non zero in order for ‘old energy’ from prior surface emissions to be combined with ‘new energy’ from the Sun.” ]
But the duration of the delay is precisely the point, that’s how long this “old energy” is available to combine with “new energy”. It’s insignificant. You’re imagining that this “old energy” is cumulative, it is not.
Does the planet Mercury make the sun hotter since it’s emitting photons back towards the sun’s surface?
Thomas,
“Order of minutes? So, the laws of physics are being suspended then.”
Why do you think physics needs to be suspended? Is physics suspended when energy is stored in a capacitor? How does storing energy as a non ground state GHG molecule, or as the temperature of liquid/solid water in a cloud any different? What law of physics do you think is being suspended?
Each time a GHG absorbs a photon, temporarily storing energy as a time varying EM field, and emits another photon as it returns to the ground state, the photon goes in a random direction. The path the energy takes can be many 1000’s of times longer than a direct path from the surface to space.
“The path the energy takes can be many 1000’s of times longer than a direct path from the surface to space.”
How about 384,000? Is that “many of 1000’s”? That’s two minutes of bouncing 40K @ur momisugly 3200 trips per second.
Think of it rather as a wave, a relentless wave. Heat continually seeks escape, it does not delay.
“Think of it rather as a wave, a relentless wave. Heat continually seeks escape, it does not delay.”
But we are taking about photons here and to escape means either leaving the top of the atmosphere or leaving the bottom and returning to the surface and being massless, the photon has no idea which was is up or down. And 100’s of thousands of ‘bounces’ between GHG molecules is not unreasonable. But the absolute time is meaningless and in fact the return to the surface of absorbed emissions from one point in time are spread out over a wide region of time in the future. All that matters is that the round trip time from the surface and back to the surface is > 0.
Very interesting analysis, but this is far too complicated for climate scientists/MSM and will be ignored.
“but this is far too complicated …”
Actually, its not complicated enough.
Because another force exceeds it. Water vapor over powers all of the co2 forcing.
Here https://micro6500blog.wordpress.com/2016/12/01/observational-evidence-for-a-nonlinear-night-time-cooling-mechanism/
And measured effective sensitivity at the surface.
here https://micro6500blog.wordpress.com/2016/05/18/measuring-surface-climate-sensitivity/
“Because another force exceeds it.”
Water vapor is not a force, but operates in the same way as CO2 absorption, except as you point out, H2O absorption is a more powerful effect. When I talk about the GHG effect, I make no distinction between CO2, H2O or any other LWIR active molecule.
well I was referring to the force of it’s radiation as it was being emitted, but fair enough. Also since they over lap there could be some interplay between them that is not expected.
References:
Trenberth et al 2011jcli24 Figure 10
This popular balance graphic and assorted variations are based on a power flux, W/m^2. A W is not energy, but energy over time, i.e. 3.4 Btu/eng h or 3.6 kJ/SI h. The 342 W/m^2 ISR is determined by spreading the average 1,368 W/m^2 solar irradiance/constant over the spherical ToA surface area. (1,368/4 =342) There is no consideration of the elliptical orbit (perihelion = 1,416 W/m^2 to aphelion = 1,323 W/m^2) or day or night or seasons or tropospheric thickness or energy diffusion due to oblique incidence, etc. This popular balance models the earth as a ball suspended in a hot fluid with heat/energy/power entering evenly over the entire ToA spherical surface. This is not even close to how the real earth energy balance works. Everybody uses it. Everybody should know better.
An example of a real heat balance based on Btu/h follows. Basically (Incoming Solar Radiation spread over the cross sectional area) = (U*A*dT et. al. leaving the lit side perpendicular to the spherical surface ToA) + (U*A*dT et. al. leaving the dark side perpendicular to spherical surface area ToA) The atmosphere is just a simple HVAC/heat balance/insulation problem.
http://earthobservatory.nasa.gov/IOTD/view.php?id=7373
“Technically, there is no absolute dividing line between the Earth’s atmosphere and space, but for scientists studying the balance of incoming and outgoing energy on the Earth, it is conceptually useful to think of the altitude at about 100 kilometers above the Earth as the “top of the atmosphere.” The top of the atmosphere is the bottom line of Earth’s energy budget, the Grand Central Station of radiation. It is the place where solar energy (mostly visible light) enters the Earth system and where both reflected light and invisible, thermal radiation from the Sun-warmed Earth exit. The balance between incoming and outgoing energy at the top of the atmosphere determines the Earth’s average temperature. The ability of greenhouses gases to change the balance by reducing how much thermal energy exits is what global warming is all about.”
ToA is 100 km or 62 miles. It is 68 miles between Denver and Colorado Springs. That’s not just thin, that’s ludicrous thin.
The GHE/GHG loop as shown on Trenberth Figure 10 is made up of three main components: upwelling of 396 W/m^2 which has two parts: 63 W/m^2 and 333 W/m^2 and downwelling of 333 W/m^2.
The 396 W/m^2 is determined by inserting 16 C or 279K in the S-B BB equation. This result produces 55 W/m^2 of power flux more than ISR entering ToA, an obvious violation of conservation of energy created out of nothing. That should have been a warning.
ISR of 341 W/m^2 enter ToA, 102 W/m^2 are reflected by the albedo, leaving a net 239 W/m^2 entering ToA. 78 W/m^2 are absorbed by the atmosphere leaving 161 W/m^2 for the surface. To maintain the energy balance and steady temperature 160 W/m^2 rises from the surface (0.9 residual in ground) as 17 W/m^2 convection, 80 W/m^2 latent and 63 W/m^2 LWIR (S-B BB 183 K, -90 C or emissivity = .16) = 160 W/m^2. All of the graphic’s power fluxes are now present and accounted for. The remaining 333 W/m^2 are the spontaneous creation of an inappropriate application of the S-B BB equation violating conservation of energy.
But let’s press on.
The 333 W/m^2 upwelling/downwelling constitutes a 100% efficient perpetual energy loop violating thermodynamics. There is no net energy left at the surface to warm the earth and there is no net energy left in the troposphere to impact radiative balance at ToA.
The 333 W/m^2, 97% of ISR, upwells into the troposphere where it is allegedly absorbed/trapped/blocked by a miniscule 0.04% of the atmosphere. That’s a significant heat load for such a tiny share of atmospheric molecules and they should all be hotter than two dollar pistols.
Except they aren’t.
The troposphere is cold, -40 C at 30,000 ft, 9 km, < -60 C at ToA. Depending on how one models the troposphere, average or layered from surface to ToA, the S-B BB equation for the tropospheric temperatures ranges from 150 to 250 W/m^2, a considerable, 45% to 75% of, shortfall from 333.
(99% of the atmosphere is below 32 km where energy moves by convection/conduction/latent/radiation & where ideal S-B does not apply. Above 32 km the low molecular density does not allow for convection/conduction/latent and energy moves by S-B ideal radiation et. al.)
But wait!
The GHGs reradiate in all directions not just back to the surface. Say a statistical 33% makes it back to the surface that means 50 to 80 W/m^2. A longer way away from 333, 15% to 24% of.
But wait!
Because the troposphere is not ideal the S-B equation must consider emissivity. Nasif Nahle suggests CO2 emissivity could be around 0.1 or 5 to 8 W/m^2 re-radiated back to the surface. Light years from 333, 1.5% to 2.4% of.
But wait!
All of the above really doesn’t even matter since there is no net connection or influence between the 333 W/m^2 thermodynamically impossible loop and the radiative balance at ToA. Just erase this loop from the graphic and nothing else about the balance changes.
BTW 7 of the 8 reanalyzed (i.e. water board the data till it gives up the right answer) data sets/models show more power flux leaving OLR than entering ASR ToA or atmospheric cooling. Trenberth was not happy. Obviously, those seven data sets/models have it completely wrong because there can’t possibly be any flaw in the GHE theory.
The GHE greenhouse analogy not only doesn’t apply to the atmosphere, it doesn’t even apply to warming a real greenhouse. (“The Discovery of Global Warming” Spencer Weart) It’s the physical barrier of walls, glass, plastic that traps convective heat, not some kind of handwavium glassy transparent radiative thermal diode.
The surface of the earth is warm for the same reason a heated house is warm in the winter: Q = U * A * dT, the energy flow/heat resisting blanket of the insulated walls. The composite thermal conductivity of that paper thin atmosphere, conduction, convection, latent, LWIR, resists the flow of energy, i.e. heat, from surface to ToA and that requires a temperature differential, 213 K ToA and 288 K surface = 75 C.
The flow through a fluid heat exchanger requires a pressure drop. A voltage differential is needed to push current through a resistor. Same for the atmospheric blanket. A blanket works by Q = U * A * dT, not S-B BB.
The atmosphere is just a basic HVAC system boundary analysis.
Open for rebuttal. If you can explain how this upwelling/downwelling/”back” radiation actually works be certain to copy Jennifer Marohasy as she has posted a challenge for such an explanation.
This explains how it works
, it’s just not what we’re being told. Scale on left of for all 3 traces, but each are different units. W’s/m^2, Percentage and Degrees F
https://micro6500blog.wordpress.com/2016/12/01/observational-evidence-for-a-nonlinear-night-time-cooling-mechanism/
micro:
I’ve tried to explain why you are wrong with this, and I know I won’t succeed, but in my mission to deny ignorance, then again….
You say on your blog:
“An analysis of nightly cooling has identified non-linearity in cooling rates under clear sky no wind conditions that is not due to equilibrium with the with the radiative temperature of the sky. This non-linearity regulates surface temperature cooling at night, and is temperature and dew point dependent, not co2, and in fact any additional warming from Co2 has to be lost to space, before the change to the slower cooling rate.”
in a sufficiently moist boundary layer, then yes the WV content does modulate (reduce) surface cooling.
however, at some point the WV content falls aloft of the moist layer and it continues at that point. If fog forms then the fog top is the point at which emission takes place an it cools there. That is how fog continues to cool through it’s depth, via the diffusion down of the cooling.
Also there are BL WV variations across the planet, and CO2 acts greatest in the driest regions.
“Water vapor controls cooling, not co2. Consider deserts and tropics as the 2 extreme examples, deserts, mostly co2 limited cooling drop on average of 35F in a night, there tropics controlled by water drop on average 15F at night. Lastly the only way co2 can affect Temps is to reduce night time cooling, it doesn’t.”
Both GHG’s “control” cooling. It is not one OR the other. Both.
You take two examples at each extreme and come up with CO2 as the supposed cooling regulator. It’s not. Meteorology explains them. Not GHE theory.
Yes the tropics have WV modulation in cooling, limiting it.
Deserts have a lack of WV and that leads to greater cooling.
That has nothing to do with CO2 which still has an effect on both over and above that that WV does.
Particularly so in deserts. Without it deserts would get colder at night.
Also at play in deserts is dry sandy surface and light winds, which feedback as the air cools (denser) to still the air more and aid the formation of a shallow inversion.
That is why deserts warm up so quickly in the morning – the cooling only occurred in a shallow surface based layer of perhaps 100 ft ( depends on wind driven mixing ).
As a proportion of the cooling of the atmosphere it is tiny.
This is why sat trop temp data needs to know where surface inversion lie as it is such a tiny but sig part of the estimation of surface temp regionally.
“This is the evidence that supports my theory that water vapor regulated nightly cooling, and co2 doesn’t do anything.
Increasing relative humidity is the temperature regulation of nightly cooling, not co2.”
No.
Both.
You just cannot see the CO2 doing it’s thing.
Unless you measure it spectroscopically – as this experiment did….
http://phys.org/news/2015-02-carbon-dioxide-greenhouse-effect.html
micro: Just basic meteorology
You have only slain a Sky-dragon
Tone, and how many times do I need to tell your there is no visible fog? What we have are multiple paths to space from the surface to space. The optical window is open all of the time. But another large part of the spectrum (and yes, you’d need spectrography to see it) opens and closes with rel humidity. And it switches by temperature. What you don’t know is that is how they make regulators work.
And I have never denied that co2 has a spectrum. What I have never found is any effect on minimum temps. And I found proof why.
Tone, you need to up your game, not me. Go show my chart to some of your Electrical Engineering buddies, they should understand it. Well or not, I’m very disappointed by people these days.
Effectively it is only one, WV.
Now let me try one more time.
Yes, the dry rate is limited by co2. But the length of time in the high cooling rate mode isn’t, it is temperature controlled.
So say dew points are 40, and air temp is 70F, and because of co2 it’s actually 73F. Dew point is still 40. And the point it gets to 70% rel humidity is the same before or after the extra 3F. So lets say this point is 50F, without the extra co2 it cools 6 hours to 50F, then starts reducing the cooling rate. In the case of the 73 degrees with the extra heat of co2, it cools 6 hours and 10 minutes, and then at the same 50F the cooling rate slows down. Now true, the slow rate is maybe a bit slower, but it too is likely not a linear add, and it has 10 minutes less to cool, but Willis and Anthony’s paper show this effect from space, it is why it follows Willis’s nice curve.
And you get that 10 minutes back as the days get longer.
“Tone, and how many times do I need to tell your there is no visible fog? What we have are multiple paths to space from the surface to space. The optical window is open all of the time. But another large part of the spectrum (and yes, you’d need spectrography to see it) opens and closes with rel humidity. And it switches by temperature….”
micro:
No it doesn’t.
Window opening/closing !
Visible fog it not needed. I use that as the extreme case. As I said what you say is true … except it does not negate the effect that CO2 has.
CO2 is simply an addition to what WV does. WV does not take CO2 magically out of the equation. The “fog” is simply thicker in the wavelengths they both absorb at but to boot CO2 has an absorption line at around 15 micron, the wavelength of Earth’s ave temp, and at ~4 micron. This would not not be in your WV window in any case and where CO2 is most effective, especially in the higher, drier atmos.
“What you don’t know is that is how they make regulators work.
And I have never denied that co2 has a spectrum. What I have never found is any effect on minimum temps. And I found proof why.
http://www.knmi.nl/kennis-en-datacentrum/publicatie/global-observed-changes-in-daily-climate-extremes-of-temperature-and-precipitation
“Trends in the gridded fields were computed and tested for statistical significance. Results showed widespread significant changes in temperature extremes associated with warming, especially for those indices derived from daily minimum temperature. Over 70% of the global land area sampled showed a significant decrease in the annual occurrence of cold nights and a significant increase in the annual occurrence of warm nights. Some regions experienced a more than doubling of these indices. This implies a positive shift in the distribution of daily minimum temperature throughout the globe. Daily maximum temperature indices showed similar changes but with smaller magnitudes. ”
And….
http://onlinelibrary.wiley.com/doi/10.1002/joc.4688/full
“The layer of air just above the ground is known as the boundary-layer, and it is essentially separated from the rest of the atmosphere. At night this layer is very thin, just a few hundred meters, whereas during the day it grows up to a few kilometres. It is this cycle in the boundary-layer depth which makes the night-time temperatures more sensitive to warming than the day.
The build-up of carbon dioxide in the atmosphere from human emissions reduces the amount of radiation released into space, which increases both the night-time and day-time temperatures. However, because at night there is a much smaller volume of air that gets warmed, the extra energy added to the climate system from carbon dioxide leads to a greater warming at night than during the day.”
Tone, their attribution is wrong, min temps have changed because dew points changed. Dew points are following just where the wind blew the water vapor as the oceans shuffle warm water around. But you still do not understand nonlinear effect on cooling.
“Tone, their attribution is wrong, min temps have changed because dew points changed. Dew points are following just where the wind blew the water vapor as the oceans shuffle warm water around. But you still do not understand nonlinear effect on cooling.”
micro:
Dp’s may have risen …. that is what an increasing non-condensing GHG will do.
And you cannot use the wind direction argument as it was a global study not a regional one.
As would the pdo changing phase, and the planet is not equally measured, as well as there are long term thermal storage in the oceans. That proves nothing. And yet what I have does prove WV is regulating cooling.
Nicholas,
“The surface of the earth is warm for the same reason a heated house is warm in the winter:”
There is a difference where the insulation in a house does not store or radiate any appreciable amount of radiation while CO2 and clouds do.
Sure they do (your inside wall is radiating like mad at room temps), it is just more opaque than the co2 in the air. I’m sure you’ve seen pictures of people through walls….
“appreciable” was the key word here. Fiberglass has no absorption lines, nor does it have much heat capacity. Insulation occurs as a result of the air trapped within where only radiation can traverse the gap and there is not enough photons for this to happen. Consider how a vacuum bottle works.
I’ll accept “appreciable” 🙂
Fiberglass, should have a bb spectrum though.
micro6500,
“Fiberglass, should have a bb spectrum though.”
Yes, as all matter does. The point is that this bb spectrum is not keeping the inside of the house warmer than it would be based on the heater alone. Slowing down the release of heat is what keeps the inside warm and if you start with a cold room and insulate it, the room will not get warmer.
The bb spectrum from clouds and line emissions from GHG’s directed back to the surface does make the surface warmer than it would be based on incoming solar energy alone.
Keep in mind that the GHG effect and clouds is not only slowing down cooling, it’s enhancing warming to be more than it would be based on solar energy alone.
“Keep in mind that the GHG effect and clouds is not only slowing down cooling, it’s enhancing warming to be more than it would be based on solar energy alone.” not really, outgoing regulation of radiation to dew point eliminates almost all of this.
Sorry I don’t have time to read thru this right now . But I do not understand why in all these years people still don’t seem to know a general expression for the equilibrium temperature for arbitrary source and sink power spectra and an arbitrary object
absorptivity=emissivityspectrum . ε is just a scalar for a flat , gray , spectrum .I go thru the experimentally testable classically based calculations at http://cosy.com/#PlanetaryPhysics . It’s essentially the temperature for a gray body in the same situation ( which is the same as for black body and simply dependent on the total energy impinging on the object ) , times the 4th root of the ratio of the dot products of the relevant spectra . It is the temperature such that
dot[ solar ; objSpectrum ] = dot[ Planck[ T ] ; objSpectrum ]Given an actual measured spectrum of the Earth ( or any planet ) as seen from space , an actual equilibrium temperature can be calculated without just parroting 255K or whatever which is about 26 degrees below the 281 gray body temperature at our current perihelion point in our orbit .
By the Divergence Theorem , no spectral filtering phenomenon can cause the interior of our ball , ie : our surface , to be hotter than that calculated for the radiative balance for our spectrum as seen from space .
Nicholas:
Just as a matter of curiosity ….
Would you have, in a previous life, been NikFromNYC ?
Oh, and I rebutted this nonsense in a recent thread.
Than I told you you we a Sky-dragon slayer in a reply to your reply.
BTW: Have seen this exact post of yours up on a well known home of Sky-dragon slaying science.
I’m only a Texas housewife, but when we Texas housewives see somebody doing Stefan-Boltzmann calculations start with average radiation figures rather than taking the time variation of the incoming radiation and integrating, we suspect someone has chosen an inappropriate method. Y’all.
Exactly (I’m learning), the average of 60 and 70 F is not 65F, which is done to every mean temp used (BEST, GISS, CRU, they all do it)
“the average of 60 and 70 F is not 65F”
Yes, but if you turn 60F and 70F into emissions, average the result and convert back to a temperature, you get a more proper average temperature which will be somewhat more than 65F. If you just average temperatures, a large change in a cold temperature is weighted more than a smaller change in a warmer temperature, even as the smaller change in the warmer temperature takes more incoming flux to maintain.
I have been adding this into my surface data code.
“the average of 60 and 70 F is not 65F”
If you want to average in terms of 4th powers, the average is 65.167F. Not a huge difference.
“If you want to average in terms of 4th powers, the average is 65.167F. Not a huge difference.”
Yes, but there’s a huge difference when averaging across the limits of temperature found on the planet and the assumption of ‘approximate’ linearity is baked in to the IPCC sensitivity and virtuall all of ‘consensus’ climate science. BTW, since sensitivity goes as 1/T^3, the difference in sensitivity is huge as well. At 260K and an emissivity of 0.62, the sensitivity is 0.494 C per W/m^2, while at 330K, the sensitivity is only 0.198 C per W/m^2, for more than a factor of 2 difference between the sensitivity of the coldest and warmest parts of the planet. Because this defies the narrative, many warmists deny the physics that tells us so.
This leads to another issue with ‘consensus’ support for a high sensitivity which is often ‘measured’ in cold climates and extrapolated to the rest of the planet. You may even be able to get a sensitivity approaching 0.8C somewhere along the 0C isotherm, where the GHG effect from water vapor kicks in. Anyone who thinks that the sensitivity of a thin slice of the planet at the isotherm of 0C can be extrapolated across the entire planet has definitely not thought through the issue.
Typo it is 65.067
It makes a pretty decent difference when you are averaging a lot of stations.
” a pretty decent difference when you are averaging a lot of stations”
No, if you have 1000 at 60 and 1000 at 70, the average is still 65.067. And it isn’t amplified if they are scattered. You can easily work out a general formula. If m1 is the mean in absolute, and m4 is the 4th power mean, then m4 is very close to m1 + 1.5*&sigma^2/m1. So if the mean is 65F and the average spread is 5F, the error is still 0.067. It’s much less than people think.
I’d have to go look, but the difference with about 80 million stations was about a degree.
No, because I calculated it both ways, and it was more than a small fraction. And the mean value that’s fed into all of the surface series all have this problem, and it’s more than 10 degrees apart. And they are not measured, they are calculated from min and max(at least this is how the gsod dataset is made).
That is not the only problem with this post.
Rhoda,
So, you don’t accept that the equivalent BB temperature of the Earth is 255K corresponding to the average 240 W/m^2 of emissions?
This is the point of doing the analysis in the energy domain. Averages of energy and emissions are relevant and have physical significance. The SB law converts the result to an EQUIVALENT average temperature.
The fact that the prediction of this model is nearly exact (Figure 3) is what tells us that the sensitivity is equivalent to the sensitivity of a gray body emitter.
No, because of the moon. Which has an actual measured average temp different to that. And because the moon’s temp variation is affected by heat retention of the surface and rate of rotation. Because the astronomical albedo (it seems to me) is not exactly what you need to determine total insolation because of glancing effects at the terminator.
But most of all because of T to the fourth. You can’t take average temp as an input to T^4. The average of T + x and T – x is T. The average of (T +x)^4 and (T -x)^4 is not T^4. It isn’t even near enough for govt work when you are talking fractions of a watt/m2.
Y’all.
Rhoda,
“Moon … Which has an actual measured average temp different to that”
This is not the case. The Moon rotates slow enough that rather than dividing the input power by 4 to accommodate the steradian requirements, you divide by a little more than 2 to get the average temperature of the lit side of the Moon. When you do this, you get the right answer. The temperature of the dark side (thermal emissions) exponentially decays towards zero until the Sun rises again.
Replying to your latest. Of course you can make the moon work by choosing the right divisor. But this seems glib. It will not do to just use a lot of approximations and fudges. One would almost think you were designing a GCM. You can’t average the heat first. You can’t ignore glancing insolation on a shiny planet. Most of all you are deceiving yourself if you use a closed-system radiation model and don’t think about all the H2O and what it does. Or at least that’s how it seems from a place in north Texas between a pile of ironing and a messy kitchen, y’all.
Rhoda,
Modelling is all about approximating behavior with equations. You start with the first order effects and if it’s not close enough, go on to model higher order effects and stop when its good enough. There will never be perfect model, except as it pertains to an ideal system, which of course never exist in nature. It seems that all of the objections I have heard about this are regarding higher order deviations that in the real world hardly matter as evidenced by Figure 3.
What I have modelled is the fundamental first order effect of matter absorbing and emitting energy based on science that has been settled for a century. When I apply the test (green line as a predictor of the red dots in Figure 3) it was so close, I didn’t need to go further, nonetheless, I did and was able to identify and quantify the largest deviation from the first order model (water vapor kicking in at about 0C). It’s also important to understand that the reason I generated the plot in Figure 3 was to test the hypothesis that from a macroscopic point of view, the planet behaves like a gray body emitter. Sure enough, it does.
In fact, the model matches quite well for monthly averages covering slices of latitude and is nearly as good when comparing at 280 km square grids across the entire surface. Long term averages match so well, even at the grided level, it’s hard to deny the applicability of this model that many seem to think is too simple. It’s not surprising that many think this way since consensus climate science has added layer upon layer of obfuscation and complexity to achieve the wiggle room necessary to claim a high sensitivity.
I guarantee that if you run any GCM and generate the data needed to produce the scatter diagram comparing the surface temperature to the planet emissions, the result will look nothing like the measured data seen in Figure 3, because if it did, the models would be predicting a far lower sensitivity than they do.
The problem as I see it is that consensus climate science has bungled the models and data too such a large extent, that nobody trusts models or data anymore. Models and data can be trusted, you just need to be transparent about what goes in to the model and how any data was adjusted. The gray body model has only 1 free variable, which is the effective emissivity and not really free, but calculated as the ratio between average planet emissions and average surface emissions.
Best post I’ve eVer seen on here and she didn’t set down her hair poofer to do it!
The IPCC definition of ECS is not in terms of 1w/m2 net forcing. It is the eventual temperature rise from a doubling of CO2, and in the CMIP5 models the median value is 3.2C. The translation to delta C per forcing is tortured, and to assert the result depends only on emissivity or change therein is simplistic and likely wrong. For example, the incoming energy from sunlight depends on albedo, and this might change (a feedback to a net forcing).
ristvan,
“The IPCC definition of ECS …”
The ECS sensitivity FACTOR is exactly as I say. Look at the reference I cited. Reforming this in terms of CO2 is obfuscation that tries to make the sensitivity exclusive to CO2 forcing, when its exclusive to Joules.
General question. Out of my depth but; does geometry enter into this in that the black and grey bodies are sphereical or at least circular? Does this impact, well, anything?
Clif,
It makes a difference when you are trying to work out how much net energy transfer between two shapes. In my thermodynamics, we included a shape factor to accommodate for this.
For these calculations, working on a very large scale – the shape factor is irrelevant. Essentially from the surface of the earth to the surface of the TOA there is no shape factor.
The use of terminology of this blog is confusing. For example: “This establishes theoretical possibilities for the planet’s sensitivity somewhere between 0.19K and 0.3K per W/m2”. This is not climate sensitivity, it is called climate sensitivity parameter (CSP). When the CSP is multiplied by forcing like 3.7 W/m2, we get the real climate sensitivity (CS). According to IPCC the transient CS = 0.5 K/(W/m2) * 3.7 W/m2 = 1.85 K and the equilibrium CS = 1 K/(W/m2) * 3.7 W/m2 = 3.7 K.
The CSP according to S-B is 0.27 K/(W/m2) as realized in this blog. Then there is only one question remaining. What is the right forcing of doubled CO2 concentration from 280 ppm to 560 ppm? IPCC says it is 3.7 W/m2. I say it is only 2.16 W/m2, because the value of 3.7 W/m2 is calculated in the atmosphere of fixed relative humidity.
aveollila,
“This is not climate sensitivity, it is called climate sensitivity parameter ”
Yes, and I make this clear in the paper where I define the climate sensitivity factor (the same thing as the parameter) and say that for the rest of the discussion it will be called simply the ‘sensitivity’.
“What is the right forcing of doubled CO2 concentration from 280 ppm to 560 ppm? IPCC says it is 3.7 W/m2.”
I’m comfortable with 3.7 W/m^2 being the incremental reduction at TOA upon instantly doubling CO2, but as I’ve pointed out, only about half of this ends up being returned to the surface in LTE since 3.7 W/m^2 is also the amount of incremental absorption by the atmosphere when CO2 is doubled and absorbed energy is distributed between exiting to space and returning to the surface.
This also brings up an inconsistency in the IPCC definition of forcing, where an instantaneous increase in absorption (decrease at TOA) is considered to have the same influence as an instantaneous increase in post albedo incident power. All of the latter affects the surface, while only half of the former does.
Ok I read the article and all the comments to date and as an MS in Engineering have a fair understanding of thermodynamics and physics in general but can not make heads nor tails of the presented data. What I can say is that the problem of isolating causation of weather/climate changes to one variable in a complex system is problematic at best. CO2 moving from 3 parts per 10,000 to 4 parts per 10,000 as the base for all climate change shown in models truly requires a leap of faith and I am unable to accurately predict both the location and speed of faith particles.
Irrational D,
“can not make heads nor tails of the presented data’
What’s confusing to you? The data is pretty simple and is a scatter diagram representing the relationship between the surface temperature and the planet emissions. The green line in Figure 3 is the prediction of the model and the red dots are monthly averages from satellites that conform quite well to the predictions.
Note that the temperature averages are calculated as average emissions converted to a temperature (satellites only measure emissions, not temperature which is an abstraction of stored energy). If I plot surface emissions (rather than temperature) vs. emissions by the planet, it’s a very linear line with a slope of about 1.6 W/m^2 of surface emissions per W/m^2 of planet emissions.
Here are some thought experiments.
What would the average temperature of the surface be if the atmosphere contained 1 ATM of O2 and N2, the planet had no GHG’s or water and reflected 30% of the incident solar energy? (notwithstanding the practicality of such a system)
The answer is 255K and based on the lapse rate, the average kinetic temperature of the O2 and N2 would start at about 255K at the surface and decrease as the altitude increased.
Now, add 400 ppm of CO2 to the atmosphere and see what would happen. Will the surface warm?
Add some clouds to the original system. Under what conditions would the surface warm or cool? (clouds can do both)
Another thought experiment is to consider a water world and while somewhat more complicated, is still far simpler to analyze than the actual climate system. Will the temperature of this surface ever exceed about 300K which is the temperature where latent heat from evaporation start to appreciably offset incoming energy from the Sun? (Think about why Hurricanes form when the water temperature exceeds this).
“What would the average temperature of the surface be if the atmosphere contained 1 ATM of O2 and N2, the planet had no GHG’s or water and reflected 30% of the incident solar energy? (notwithstanding the practicality of such a system)”
Soln: Use your Fig. 2 with no other modes of energy transfer, only radiative energy transfer, in radiative equilibrium illuminated by SW source from the right at 342 W/m^2. The steady state allows text book energy balance by 1LOT of the left slab, add to your arrows (+ to left) w/the SW energy into left slab BB surface minus energy out 1LOT.
(Left going) – right going energy arrows = 0 in steady state with O2/N2 low emissivity A = .05 say:
SW*(1-albedo) + Ps(A/2) – Ps = 0
342*(1-0.3) + Ps(A/2-1) = 0
240 – Ps(0.05/2-1) = 0
240 + 0.975 Ps = 0
Ps= 246 (glowing at terrestrial wavelengths to the right)
Ps = sigma*T^4 = 246
T = (246/0.0000000567) ^ 0.25 = 257 K
Yes, I agree with your answer of 255K but a slight difference in that I made the O2/N2 gray body physical with their low (but non-zero) emissivity & absorptivity (very transparent across the spectrum, optically very thin).
——
”Now, add 400 ppm of CO2 to the atmosphere and see what would happen. Will the surface warm?”
Soln: Try your model with emissivity A=0.8 with colloid water droplets, wv, CO2 et. al. as is measured for the real Earth global atm. looking up:
240 – Ps(0.8/2-1) = 0
240 + 0.6Ps = 0
Ps = 400 (glowing at terrestrial wavelengths to the right)
T = (400/0.0000000567) ^ 0.25 = 290.7 K
Your model reasonably well checks out with thermometer, satellite observations for a simple text book analogue of the global surface T, a model that can not be pushed too far.
Trick,
You are over-estimating a bit for the 400ppm CO2 case. Based on HITRAN line by line analysis, 400 ppm of CO2 absorbs about 1/4 of the surface energy and on the whole contributes only about 1/3 to the total GHG effect, thus A (absorption, not emissivity) is about 0.25 and the emissivity is (1 – A/2) = 0.875 and the surface power gain is 1.14. Given 240 W/m^2 of input, the surface will emit 1.14*240 = 274 W/m^2 which corresponds to a surface temperature of about 264K.
The 1/4 surface energy absorbed by CO2 is calculated at 287K and not 264K, which because its a lower temperature, the 15u line becomes more important and A is increased a bit. Note that on Venus, the higher surface temperature moves the spectrum so far away from the main 15u CO2 line that its GHG effect is smaller than for Earth, despite much higher concentrations (the transparent window is still transparent) and only the weaker lines at higher wavelengths become relevant to any possible CO2 related GHG effect on the surface of Venus.
Does Hitran do a changing evolution of night time cooling or is it a static snapshot? Because if it’s a snapshot it does not tell you what’s happening.
micro6500,
MODTRAN and the version I wrote, both of which are driven by HITRAN absorption line data do the same thing which is a static analysis, however; you can run the static analysis at every time step. What I’ve done is run it for number of different conditions and then interpolate the results since most conditions fall between 2 characterized conditions. It runs much faster that way and looses little accuracy since a full blown 3-d atmospheric simulation is rather slow. Surprisingly to many, you can even establish an scalar average absorption factor and apply it to averages and the results are nearly as good. This is not all that surprising owing to the property of superposition in the energy domain.
BTW, is your handle related to the Motorola 6500 cpu? I’ve worked on designing Sparc CPU’s myself, most notably the PowerUp replacement CPU for the SparcStation.
Yes, the the dynamics I’ve found has to involve the step by step change, or it’ll just appear as a static transfer function.
Didn’t Harris have a cmos 6500? No. It’s my name, and a unique identifier. But I have done both ic failure analysis (at Harris), asic design for NASA, and 7 years at valid logic and another at view logic. And work for Oracle:)
Modtran is a static timing verifier, this needs a dynamic solution.
micro6500,
Yes, MODTRAN is purely static and hard to integrate into other code, which is why I rolled my own. But, you can make it dynamic by running it at each time step, or whenever conditions change, enough to warrant re-running it’s just a pain and real slow.
Which is why all of the results from it are worthless, just I doubt the professionals took the time, and the amateurs don’t know any better.
Top post: “This leads to an emissivity for the gray body atmosphere of A”
1:56pm: “thus A (absorption, not emissivity) is about 0.25”
So which do you mean true for your A?
Actually, physically, your A in Fig. 2 is emissivity of the gray body block radiating 1/2 toward the BB and 1/2 toward the right as shown in Fig. 2. arrows. Absorptivity and emissivity are equal at any wavelength for a given direction of incidence and state of polarization. The emissivity of the current atm., surface looking up, has been extensively measured in the literature, found to be around 0.7 in dry arctic regions and around 0.95 equatorial humid tropics. My use of 0.8 global thus is backed reasonably by measurements over the spectrum and a hemisphere of directions.
Trick,
OK, so you were using emissivity for the system with water vapor, clouds and everything else, while the experiment was 400 ppm of CO2 and nothing else.
The A is absorption of the gray body atmosphere and equal to its emissivity. The emissivity of the gray body emitter (the planet as a system) is not the same as that of the gray body atmosphere (unless the atmosphere only emitted into space) and is related to the emissivity of the gray body atmosphere, A by, e = (1-A/2).
But, your values for A as measured are approximately correct, although I think the actual global average value of A is closer to 0.75 than 0.8 but it’s still in the ballpark. The average measured emissivity of the system is about 0.62.
And in the rest of the world it changes from the dry end at sunset (depending of the days humidity) to the wet end every night by the time the sun comes up in the morning.
“the experiment was 400 ppm of CO2 and nothing else.”
The experiment was “add 400 ppm of CO2 to the atmosphere” which was unclear if meant the current atm. or your N2/O2 atm. I expressly wrote colloid water droplets, wv, CO2 et. al. as is measured for the real Earth global atm. looking up. Use any reasonable measured 400ppm CO2 in N2/O2 emissivity and your analogue will find the reasonable global surface temperature for that scenario (somewhere between 257K and 290.7 K).
“The average measured emissivity of the system is about 0.62.”
I see this often; it is incorrect. For illumination = 240W/m^2, BB Teff = 255K from sigma*T^4= 240. This is the equivalent blackbody temperature an observer on the moon would infer for Earth looked upon as an infrared sun. Earth satellites measure scenario brightness temperature ~255K (avg.d 24/7/365 over 4-10 years orbits) from ~240 W/m^2.
Just as we on Earth say that the sun is equivalent to a ~6000 K blackbody (based on the solar irradiance), an observer on the moon would say that Earth is equivalent to a 255 K blackbody (based on the terrestrial irradiance). Note that the effective brightness temperature 255K in no (direct) way depends on the emissive properties of Earth’s atmosphere. 240 in and 240 out ~radiative equilibrium ~steady state means 255K BB temperature observed from space.
Trick,
“This is the equivalent blackbody temperature an observer on the moon would infer for Earth looked upon as an infrared sun.”
Yes, 255K is the equivalent BB temp of the planet. However; this is predicated on the existence of a physical emission surface that radiates 240 W/m^2. This is an abstraction that has no correspondence to reality since no such surface exists and the photons that leave the planet originate from all altitudes between the surface to the boundary between the atmosphere and space. The only ‘proper’ emission surface is the virtual surface comprised of the ocean surface plus bits of land that poke through and that is in equilibrium with the Sun. Even most of the energy emitted by clouds originated at the surface. Clouds do absorb some solar energy, but from a macroscopic, LTE point of view, the water in clouds is tightly coupled to the water in the oceans and we can consider energy absorbed by clouds as equivalent to energy absorbed by the surface.
If the virtual surface in equilibrium with the Sun is the true emitting surface, then the gray body model with an emissivity of 0.62 more accurately reflects the physical system.
“Yes, 255K is the equivalent BB temp of the planet. However; this is predicated on the existence of a physical emission surface that radiates 240 W/m^2.”
There is no such thing “predicated”. The ~240 is measured by many different precision radiometer instruments at the various satellite orbits, collectively known as CERES, earlier (1980s) ERBE.
Trick,
” The ~240 is measured by many different precision radiometer instruments ”
Yes, and I’m not saying otherwise, but to be a BB, there must be an identifiable surface that emits this much energy and there is no identifiable surface that emits 240 W/m^2, that is, you can not enclose the planet with a surface of any shape that touches all places where photons are emitted and combined emit 240 W/m^2.
Many get confused by the idea that there is a surface up there whose temperature is 255K, but this is not the surface emitting 240 W/m^2. This represents the kinetic temperature of gas molecules in motion, per the Kinetic Theory of Gases. Molecules in motion emit little, it any energy, unless they happen to be LWIR active (i.e. a GHG). Higher up in the thermosphere, the kinetic temperature exceeds 60C, but the planet is certainly not emitting that much energy. In fact, there are 4 identifiable altitudes whose kinetic temperature is about 255K, one at about 5 km, another at about 30 km, another at about 50 km and another at about 140 km.
If we examine the radiant temperature, that is the temperature associated with the upwards photon flux, it decreases monotonically from the surface temperature down to about 255K at TOA.
Perhaps you missed this of mine at 6:40pm: Note that the effective brightness temperature 255K in no (direct) way depends on the emissive properties of Earth’s atmosphere. Thus neither atm. temperatures. Take Earth atm. completely away, keep same albedo, and once again radiative equilibrium will establish at 240 output for same input. Change albedo (input), change the 240 (output).
You are trying to discuss, I think, within the atm. a level for the optimal tradeoff between high atm. density (therefore high atm. emissivity) and little overlying atm. to permit the atm. emitted radiation to escape to deep space. Most (but by no means all) of the outgoing atm. radiation observed by CERES et. al. comes from a level 1 optical thickness unit below TOA (for optical path defined 0 at surface). This has no effect at all on the 240 (as observed from moon say), as removing the atm. with same albedo gives all 240 straight from the surface.
SIMPLE EXPLANATION FOR EARTH
Using the author’s Figure 1, let Black Body T be Earth’s surface (which does not have to be a black body emitter) and E be the atmosphere. If Earth’s atmosphere contained no greenhouse gases (H2O, CO2, CH4, etc), then E would not be an absorber of outgoing long-wave radiation, and the atmosphere would not be heated by absorbing outgoing radiation, and Earth’s surface would not be further warmed.
But Earth’s atmosphere actually has a value for E that is less than 1 (explanation below), and it does absorb outgoing radiation via the greenhouse gases. E less than 1 means E emits less radiation than it absorbs from T. The consequence of this is that E warms to a temperature greater than that of T until its radiation emission rate equals the rate it receives energy. Earth’s surface also warms in this process because E radiates back to the surface as well as into space.
Why is the emissivity of the atmosphere (E) less than 1? When more CO2 is added to the atmosphere, its concentration in higher regions of the atmosphere also increases. On average, a CO2 molecule must be at some significant height in order for the radiation it emits upward to escape to space rather than be absorbed by another higher altitude CO2 molecule. That height, called the emission height, is a few miles.
Adding more CO2 to the atmosphere causes that emission height to increase. BUT, Earth’s troposphere cools as altitude increases. And a cooler atmosphere causes the RATE of radiation emission from CO2 to decrease. Lower emission rate causes the atmosphere to warm until the CO2 emission rate at that new emission height stabilizes the temperature. Adding more CO2 increases CO2 emission height, causing the atmosphere to warm to compensate. Water behaves somewhat differently because it does not mix into the higher atmosphere and because its concentration varies significantly across Earth’s surface.
It’s not about heat flow, but about quantum radiation effects and P-T characteristics of the atmosphere.
One day, hopefully not far off, all the above complexity and confusion is going to be looked back upon with wry amusement.
There are only two ways to delay the transmission of radiative energy through a system containing matter.
i) A solid or a liquid absorbs radiation, heats up and radiates out at the temperature thereby achieved. That is where S-B can be safely applied.
ii) Gases are quite different because not only do they move up and down relative to the gravitational field but also the molecules move apart as they move upwards along the density gradient induced by mass and gravity. It is the moving apart that creates vast amounts of potential energy within a convecting atmosphere. Far more potential energy is created in that process of moving molecules apart along the density gradient than in the simple process of moving molecules upward.
The importance of that distinction is that creation of potential energy (not heat) from kinetic energy (heat) does NOT require a rise in temperature as a result of the absorption of radiation (which absorption is a result of conduction at the irradiated surface beneath the atmosphere) because energy in potential form has no temperature.
Indeed the creation of potential energy from kinetic energy requires a fall in temperature but only until such time as the kinetic energy converted to potential energy in ascent is matched by potential energy converted to kinetic energy in descent. At that point the temperature of surface and atmosphere combined rises back to the temperature predicted by the S-B equation but only if viewed from a point outside the atmosphere. The temperature of surface alone will be higher than the S-B temperature.
Altering radiative capability within the atmosphere makes no difference because convection simply reorganises the distribution of the mass content of the atmosphere to maintain long term hydrostatic equilibrium. If convection were to fail to do so then no atmosphere could be retained long term.
So. solids and liquids obey the S-B equation to a reasonably accurate approximation (liquids will convect but there is little moving apart of the molecules to create potential energy so the S-B temperature is barely affected). Gases heated and then convected upward and expanded as a result of conduction from an irradiated surface will not heat up according to S-B due to the large amount of potential energy created from surface kinetic energy. They will instead raise the surface temperature beneath the mass of the atmosphere to a point higher than the S-B prediction so as to accommodate the energy requirement of ongoing convective overturning in addition to the energy requirement of radiative equilibrium with space.
It really is that simple 🙂
So, are you suggesting that trying to apply the S-B law to Earth and Earth’s atmospheric system is itself flawed thinking ? Are we trying to force fit something that really is a misfit to begin with, in this context ?
I can see how this suggestion might antagonize those who have figured out the complexities of such an application of S-B, and to question these folks on this point seems to create yet another camp of disagreement within the already bigger camp of disagreement over catastrophic warming. … So, now we have skeptics battling skeptics who are skeptical of other skeptics.
“So, now we have skeptics battling skeptics who are skeptical of other skeptics.”
This is because there’s so much wrong with ‘consensus’ climate science, yet to many skeptics, the ONLY problem is the one they have thought about.
I characterize myself as a luke warmer, where I do not dispute that CO2 is a GHG, or that GHG’s and clouds warm the surface above what it would be without them, but there are many who believe otherwise. I definitely dispute the need for mitigation because the effect is far more beneficial than harmful. As I’ve said before, the biggest challenge for the future of mankind is how to enrich atmospheric CO2 to keep agriculture from crashing once we run out of fossil fuels to burn or if the green energy paradigm foolishly gains wide acceptance.
I see the biggest problem as over-estimating the sensitivity by about a factor of 4 and it’s this assumption from which most of the other errors have arisen in order not to contradict the mantra of doubling CO2 causing 3C of warming. Many of those who think CO2 has no effect do not question the sensitivity and use ‘CO2 doesn’t affect the surface temperature’ as the argument against instead of attacking the sensitivity.
Please note that I do accept that GHGs have an effect because they distort lapse rate slopes which causes convective adjustments so that the pattern of general circulation changes and some locations near climate zone boundaries or jet stream tracks may well experience some warming.
However, since the greenhouse effect is caused by atmospheric mass conducting and convecting any additional effect from changes in GHG amounts will probably be too small to measure especially if it does turn out that most natural climate change is solar induced.
Thus I am a lukewarmer and not a denier.
As regards S-B it is well established that it deals with radiative energy transfers only and so it is not contentious to point out that it cannot accommodate the thermal effects of non radiative energy transfers between the mass of the surface and the mass of a conducting and convecting atmosphere.
By all means apply S-B from beyond the atmosphere but that tells you nothing of the surface temperature enhancement required to fuel continuing convective overturning within the atmosphere at the same time as energy in equals energy out.
Stephen,
“By all means apply S-B from beyond the atmosphere but that tells you nothing of the surface temperature enhancement required to fuel continuing convective overturning within the atmosphere at the same time as energy in equals energy out.”
This is not the case. Each of the 240 W/m^2 of incident energy contributes 1.6 W/m^2 of surface emissions at the LTE average surface temperature, or in other words, it takes 1.6 W/m^2 of incremental surface emissions to offset the next W/m^2 of input power (in LTE, input == output). Owing to the T^4 relationship, the next W/m^2 of solar forcing (241 total input) will increase the emissions by slightly less than 1.6 W/m^2, increasing the surface temperature by about 0.3C for a sensitivity of about 0.3C per W/m^2. Figure 3 characterizes this across the range of possible average monthly temperatures found across the whole planet (about 260K to well over 300K) and this relationship tracks SB for a gray body with an emissivity of 0.62 almost exactly across all possible temperatures.
SB is the null hypothesis and the only way to discount it is to explain the red dots in Figure 3 otherwise, per the question at the end of the article.
If some people have arrived at the position that CO2 does not affect the surface temperature, then these people have no need to argue for sensitivity, since the sensitivity of something that doesn’t matter anyway also does not matter.
I am interested in HOW some of these people, seemingly who have studied the same rigorous math or physics, arrive at such a divergent conclusion. They will say that those who argue sensitivity are deluded, and those who argue sensitivity will say the same, creating another troubling subdivision that further confuses those trying to understand all this.
How can a prize-winning physicist get condemned by another prize-winning physicist, when they both study (I presume) the same curriculum of physics or math ? I think there is a consensus beneath the main consensus (a “sub-consensus”) that forbids thinkers from straying too far from THEIR assumptions.
co2isnotevil
These are the important words that underlie all that follows:
“The Earth can be accurately modeled as a black body surface with a gray body atmosphere, whose combination is a gray body emitter whose temperature is that of the surface and whose emissions are that of the planet.”
I do not accept that the combination is as simple as a grey body emitter once hydrostatic equilibrium has been achieved following the completion of the first convective overturning cycle. It is certainly a grey body emitter during the first cycle because during that period and only during that period there is a net conversion of surface kinetic energy to potential energy which is being diverted to conduction and convection instead of being radiated to space.
Once the first cycle completes the combined surface and atmosphere taken together behave as a blackbody when viewed from space and so S-B will apply from that viewpoint.
The atmosphere might radiate but not as a greybody because if it has radiative capability which causes any radiative imbalance then convection alters the distribution of the mass within the atmosphere in order to retain hydrostatic equilibrium. Thus the atmosphere (under the control of convective overturning) also radiates as a blackbody which is why the S-B equation works from a viewpoint beyond the atmosphere.
If the surface were to act as a blackbody but the atmosphere as a greybody there would be a permanent radiative imbalance which would destroy hydrostatic equilibrium and we know that does not happen even where CO2 reaches 90% of an atmosphere such as on Venus or Mars.
On both those planets the temperature at the same atmospheric pressure is very close to that at the same pressure on Earth adjusted only for the distance from the sun. That is a powerful pointer to mass conducting and convecting rather than GHG quantity being the true cause of a surface temperature enhancement above the S-B expectation.
Whether the atmosphere radiates or not there is the additional non radiative process going on which is not in George White’s above model and not dealt with by the S-B equation and which is omitted from the purely radiative AGW theory. The amount of surface energy permanently locked into the KE to PE exchange in ascent and the PE to KE exchange in descent is constant at hydrostatic equilibrium being entirely dependent on atmospheric mass and the power of the gravitational field..
The non radiative KE to PE and PE to KE exchange within convective overturning is effectively an infinitely variable buffer against radiative imbalances destroying hydrostatic equilibrium.
I recommend that you or George reinterpret the observations set out in George’s head post in light of the more detailed scenario that I suggest.
Stephen,
I agree that there’s a lot of complication going on within the atmosphere, much of which is still unknown, but it’s impossible to model the complications until you know how it’s supposed to behave and trying to out psych complex, codependent behaviors from the inside out almost never works. The only way to understand how it’s supposed to work is a top down methodology which characterizes the system at the highest level of abstraction possible whose predictions are within a reasonable margin of error with the data. This provides a baseline to compare against more complex models.
The highest level of abstraction would be black body which will be nearly absolutely accurate in the absence of an atmosphere. The purpose of this exercise was to extend the black body model to connect the dots between the behavior of a planet with and without an atmosphere.
The first thing I added was a non unit emissivity and after adding this, the results were so close to the data, it was unnecessary to make it more complicated. Of course, I didn’t stop there and have extended the model in many ways which gets even closer by predicting more measured attributes, including seasonal variability. I’ve compared it to data at the gridded level, at the slice level (from 2.5 degree slices to entire hemispheres) and globally and it works well every time. There’s even an interesting convergence criteria the system appears to seek which is that it drives towards the minimum effective emissivity and warmest surface possible, given the constraints of incoming energy and static components of the system. You can see this in the plot earlier in the comments which plots the surface emissivity (power out/surface emissions) against the surface temperature. You will notice that the current average temperature is very close to the local minimum in this relationship. I can even explain why this is in terms of the Entropy Minimization Principle.
There’s no such thing as a perfect model of the climate and in no way shape or form am I claiming that this is, but it is very accurate at predicting the macroscopic behavior of the planet especially considering how simple the model actually is.
Feel free to object on the grounds that it seems too simple to be correct, as I had the same concerns early on and could not believe that somebody else had not recognized this decades ago (Ahrrenius came close), but unless objections are accompanied with an explanation for why the red dots in Figure 3 align along a contour of the SB relationship for a gray body with an effective emissivity of 0.62, no objection has merit. I should point out that the calculations of the output power are affected by a lot of different things and that each of the roughly 26K little red dots of monthly averages were each calculated by combining many millions of unadjusted data measurements. The fact that the distribution of dots is so close to the prediction (green line) is impossible to deny and is why without another explanation for the correlation, no objection can have merit.
The source of this is the active regulation is discovered.
co2isnotevil,
Thanks for such a detailed response. I wouldn’t dream of objecting, merely supplementing it by simplifying further.
My suggestion is that the red dots in Fig 3 align along a contour of the S-B relationship because convective overturning adjusts to eliminate radiative imbalances from whatever source.
The remaining differential between the line of dots and the contour is simply a measure of the extent to which the lapse rate slopes are being distorted by radiative material within the bulk atmosphere and convection then works to neutralise the thermal effect of that distortion so that energy out to space matches energy in from space.
The consequence is that the combined surface and atmosphere always act as a blackbody (not a greybody) when viewed from space.
You have noted that there is an interesting convergence criteria ‘the system appears to seek’ and I suggest that those convective adjustments lie behind it.
Are you George White ?
Stephen,
Yes. I’m the author of the article.
The idea that the system behaves like a black body is consistent with my position, at least relative to power in vs. temperature. In fact, the Entropy Minimization Principle predicts this. Minimizing entropy means reducing deviations from ideal and 1 W/m^2 of surface emissions per W/m^2 of input is ideal.
Here is the plot that sealed it for me:
http://www.palisad.com/co2/tp/fig2.png
Unlike the output power, calculating the input power is a trivial calculation.
In this plot, the yellow dots are the same as the red dots in Figure 3 and the red dots are the relationship between post albedo incident power and temperature and where they cross is the ‘operating point’ for the planet. Note that the slope of the averages for this is the same as the magenta line, where the magenta line is the prediction of the relationship between the input power and surface temperature. This is basically the slope of SB for an ideal BB at the surface temperature, biased towards the left.
I’ve only talked about the output relationship because it’s a tighter relationship and easier to explain as a gray body, which people should be able to understand. Besides, its hard enough to get buy in to a sensitivity of 0.3C per W/m^2, much less 0.19C per W/m^2.
You really have to think of this as 2 distinct paths. One that ‘charges’ the system with a sensitivity of 0.19 and the other that ‘discharges’ the system with a sensitivity of 0.3. The sensitivity of the discharge path is higher, which is a net negative feedback like effect, but is not properly characterized as feedback per Bode.
On further reflection the gap between the red and green lines could indicate the extent to which mass and gravity have raised surface temperature above S-B.
Convective adjustments then occur to ensure that energy out to space matches energy in from space so that the curve of the red line follows the curve of the green line.
Stephen,
I already understand and have characterized the biggest deviation which is a jump in emissivity around 273K (0C). This is the influence of water vapor kicking in and decreasing the effective emissivity. I’m still not sure what’s going on near the equator, but it seems that whatever is happening in one hemisphere is offset by an opposite effect in the other, so I haven’t given it much thought. The data does have a lot of artifacts and is useless for measuring trends, and equatorial data is most suspect, but my analysis doesn’t look at or care about trends or absolute values and instead concentrates only on aggregate behavior and the shapes of the relationships between different climate variables. There are a whole lot more plots comparing various variables here:
http://www.palisad.com/co2/sens
Long term global trends, sure. And there is a lot that can be done with the data we have, you can get the seasonal change, and in the extratropics you can calculate what the 0.0 albedo surface power is, and then see how effective it was at increasing temperature.
“Long term global trends, …”
Even short term local trends. The biggest issue I have found with the ISCCP data set is a flawed satellite cross calibration methodology which depends on continuous coverage by polar satellites. When a polar satellite is upgraded and it’s only operational polar orbiter, there are discontinuities in the data, especially equatorial temperatures. I mentioned this to Rossow about a decade ago, but it has never been fixed, although I haven’t checked in over a year.
It doesn’t even show up in the errata, except as a inconspicuous reference to an ‘unknown’ anomaly in one of the plots illustrating how satellites are calibrated to each other.
Ah, some of the surface data has some use. What I have tried to do for the most part is to see what the stations we have measured. Which isn’t a GAT, even though I do averages of all of the stations as well as many different small chunks.
I am not familiar with how this blog views the ideas of Stephen W., but I must say that I find his emphasis on the larger fluid dynamic mass of the atmosphere resonant with my layperson intuition, which I admit is biased towards fluid dynamic views.
I have always wondered how radiation physics can dominate fluid dynamic physics of the larger mass of the atmosphere, and I see some hope here of reconciling the two aspects.
Robert,
“I find his emphasis on the larger fluid dynamic mass of the atmosphere resonant with my layperson intuition”
If you want to understand what’s going on within the atmosphere, then fluid dynamics is the way to go, but that is not what this model is predicting. The gray body emissions model proposed only characterizes the radiant behavior at the boundaries of the atmosphere, one boundary at the surface (which is modelled as an ideal BB radiator) and the other with space. To the extent that the relationship between the behavior at these boundaries can be accurately characterized and predicted (the green line in figure 3), how the atmosphere manifests this behavior is irrelevant, moreover; as far as I can tell, nobody in all of climate science actually has a firm grasp on what the microscopic behavior actually is or should be.
The idea that complex fluid dynamics of non linear coupled systems must be applied to predict the behavior of the climate is a red herring promoted by consensus climate science to make the system seem too complicated for mere mortals to comprehend. It’s the difference between understanding the macroscopic behavior (the gray body emission model) and the microscopic behavior (fluid dynamics …). Both can get the same answer, except that the later has too many unknowns and ‘impherical’ constants, so unless you can compare it to how the system must behave at the macroscopic level, such a model can never be validated as being correct.
Consider simulating an digital circuit that adds 2 numbers. A 64-bit adder has many hundreds of individual transistor switches. The complexity can explode dramatically when various carry lookahead schemes are implemented. The only way to properly validate that the microscopic transistor logic matches the macroscopic task of adding 2 numbers is to actually add 2 numbers together and compare this with the results of the digital logic.
Most systems can be modelled at multiple levels of abstraction and best practices for developing the most certain models is to start with the highest level of abstraction possible and then use this to sanity check more detailed models.
For example, I can guarantee that if you generated the data I presented in Figure 3 using a GCM, it would look nothing like either the measured data or the prediction of the gray body emitter. If it did, the modelled sensitivity would only be about 0.3 and no where near the 0.8 claimed by the IPCC.
Thank you.
There is some hostility here but support as well so as long I express myself in a moderate tone my submissions continue to be accepted.
I think one can reconcile the two aspects in the way I have proposed. The non radiative energy exchange between the mass of the surface and the mass of the atmosphere needs to be treated entirely independently of the radiative exchange between the Earth system and space. One can do that because there really is no direct transfer of energy between the radiative and non radiative processes once the atmosphere achieves hydrostatic equilibrium.
Instead, the convective adjustments vary the ratio between KE and PE in the vertical and horizontal planes so as to eliminate any imbalances that might arise in the radiative exchange between the Earth system (surface and atmosphere combined) and space.
So, if GHGs try to create a radiative imbalance such as that proposed in AGW theory they are prevented from doing so via changes in the distribution of the mass content of the atmosphere.
If GHGs alter the lapse rate slope in one location then that change in the lapse rate slope is always offset by an equal and opposite change in the lapse rate slope elsewhere and convection is the mediator.
GHGs do have an effect but in the form of circulation changes rather than a change in average surface temperature and the thermal effect is miniscule because it was initially the entire mass of the atmosphere that set up the enhanced surface temperature in the first place and not GHGs.
Otherwise the similarities with Mars and Venus would not exist.
When people argue over what the first principles actually are, seemingly not able to agree on them, then where is the foundation for a common understanding.?
Even the foundation of the foundation seems to have far more flexibility in interpretation than can allow for it to be the basis for that sought-after common ground.
When you guys reach a common agreement on what the Stephan Boltzmann Law says and HOW it does or does not apply to Earth, I’ll start to worry about understanding these discussions in depth. For now, I seem doomed to watch yet a deeper level of disagreement over what I naively thought was a common foundation.
I’m such a child !
Nick Stokes,
No reply to my comment here and the one below it?
https://wattsupwiththat.com/2017/01/05/physical-constraints-on-the-climate-sensitivity/comment-page-1/#comment-2390383
RW,
What you are saying seems to echo what George is saying, and I replied at length there. This sums it up:
“George’s ‘A/2’ or claimed 50/50 split of the absorbed 300 W/m^2 from the surface, where about half goes to space and half goes to the surface, is NOT a thermodynamically manifested value, but rather an abstract conceptual value based on a box equivalent model constrained by COE to produce a specific output at the surface and TOA boundaries.”
Yes, it’s not a thermodynamically manifested value, if I understand what that means. There is thermodynamics needed, and you can’t get an answer to sensitivity without it. The only constraint provided by COE is on total of flux up and down. It does not constrain the ratio.
A common weakness in George’s argument, and I think yours, is that he deduces some “effective” or “equivalent” quantity by back-working some formula in some particular circumstance, and assumes that it will apply in some other situation. I’ve disputed the use of equivalent temperature, but more central is probably the use of an emissivity of 0.62, read somehow from a graph. You can’t use this to determine sensitivity, because you have no reason to expect it to remain constant. It isn’t physical.
The give-away here is that S-B is used in situations where it simply doesn’t apply, and there is no attempt to grapple with the real equations of radiative gas transfer. S-B tells you the radiation flux from a surface of black body at a uniform temperature T. Here we don’t have surfaces (except for ground) and we don’t have uniform T. Gas radiation is different; it does involve T^4, but you don’t have the notion of surface any more. Emissivity is per unit volume, and is of course highly frequency dependent (I objected to the careless usage of grey body).
So there is so much missing from his and your comments that I’m really stuck for much more to say than that you simply have no basis for a 50-50 split, and especially one that is sufficiently fixed that its constancy will determine sensitivity.
One thing I wish people would take account of – scientists are not fools. They do do this kind of energy balance, and CS has been energetically studied, but no-one has tried to deduce it from this sort of analysis. Maybe George has seen something that scientists have missed with their much more elaborate analysis of radiative transfer, or maybe he’s just wrong. I think wrong.
Nick,
The 50/50 split itself claimed by George does NOT determine the sensitivity. It quantifies the effect that absorbed surface IR by GHGs has within the complex thermodynamic path, so far as its ultimate contribution to the enhancement of surface warming by the absorption of upwelling IR by GHGs and the subsequent non-directional re-radiation of that initially absorbed energy within the atmosphere. The physical driver of the GHE is the re-radiation of some of that initially absorbed surface IR back towards (and not necessarily back to) the surface. Since the probability of re-emission at any discrete layer is equal in any direction regardless of the rate its emitting at, you would only expect about half of what’s initially captured by GHGs to be contributing to the downward IR push the atmosphere makes at all levels, where as the other half will contribute to the upward IR push the atmosphere makes at all levels. Only the increased downward emitted IR push from the re-radiation of the energy absorbed by GHGs is further enhancing the radiative warming of the planet and ultimately the enhancement of surface warming. The 50/50 split ratio is NOT a quantification of the temperature structure or bulk IR emission structure of the atmosphere, which emits roughly double the amount of IR flux to the surface as it emits out the TOA. If it were claiming to be, it would surely be wrong (spectacularly so).
COE constrains the black box output at the surface to not be more than 385 W/m^2, otherwise a condition of steady-state does not exist. While flux equal to 385 W/m^2 must be somehow exiting the atmosphere at the bottom of the box at the surface, 239 W/m^2 must be exiting the box at the TOA, for a grand total of 624 W/m^2. The emergent 50/50 split only means an amount *equal* to half of what’s initially absorbed by GHGs is ultimately radiated to space and an amount *equal* to the other half is gained by the surface, i.e. added to the surface, somehow in some way. Nothing more. So in effect, the flow of energy in and out of the whole system is the same as if what’s depicted in the box model were occurring. The black box is constrained by COE to produce a value of ‘F’ somewhere between 0 and 1.0, and the value that emerges from the COE constraint is about 0.5. If you don’t understand where the COE constraint is coming from in the black box, let’s go over it in detail step by step.
The ultimate conclusion from the emergent 50/50 split is the *instrinsic* surface warming ability of +3.7 W/m^2 of GHG absorption (from 2xCO2) is only about 0.55C and not the 1.1C ubiquitously cited and widely accepted; however 0.55C is not a direct or precise quantification of the sensitivity. But before we can get to that component, you must first at least understand the black box component and the derived 50/50 atmospheric split.
How well do you know and understand atmospheric radiative transfer? What George is quantifying as absorption ‘A’ is just the IR optical thickness from the surface (and layers above it) looking up to the TOA, and transmittance ‘T’ is just equal to 1-‘A’. So if ‘A’ is calculated to be around 0.76, it means ‘A’ quantified in W/m^2 is equal to about 293 W/m^2, i.e. 0.76×385 = 293; and thus ‘T’ is around 0.24 and quantified in W/m^2 is about 92 W/m^2. Right?
co2isnotevil
You referred to the red dots and George says this:
“Each little red dot is the average monthly emissions of the planet plotted against the average monthly surface temperature for each 2.5 degree slice of latitude. The larger dots are the averages for each slice across 3 decades of measurements. The data comes from the ISCCP cloud data set provided by GISS, although the output power had to be reconstructed from radiative transfer model driven by surface and cloud temperatures, cloud opacity and GHG concentrations, all of which were supplied variables. ”
All they seem to show is that the temperature rose as a result of decreased cloudiness. There are hypotheses that the observed reduction in cloudiness was a result of high solar activity and unrelated to any increase in CO2 over the period.
A reduction in cloudiness will allow more solar energy in to warm the system regardless of any changes in CO2
WUWT covered the point a while ago:
https://wattsupwiththat.com/2007/10/17/earths-albedo-tells-a-interesting-story/
“The low albedo during 1997-2001 increased solar heating of the globe at a rate more than twice that expected from a doubling of atmospheric carbon dioxide. This “dimming” of Earth, as it would be seen from space, is perhaps connected with the recent accelerated increase in mean global surface temperatures.”