Greenhouse gases, are not so much “trapping” heat, as acting by “tapping” heat. They are acting as a vector (tap) enabling the flow of energy between the adiabatic controlled atmosphere and the IR radiation that eventually leaves the atmosphere. And it is because the adiabatic cooling reduces the temperature, that the apparent temperature of earth from space is cooled. This may reconcile the “Dragon slayers” with mainstream skeptic views.
Introduction: why colder means warmer
The warmer windows are warmer because to lose more heat.
Talking through my post yesterday with a physicist (The CO2 Greenhouse effect is real (sometimes), it was clear I needed to spend a bit more time explaining what may appear counter intuitive. That is why when the apparent temperature of the earth from space decreases, that this must mean the planet is warmer.
This is easiest to explain using the analogy of a house. To the right is a thermal image of a house, clearly showing the windows and doors are much warmer than the better insulated walls and roof. Why are they warmer? Because the internal heat can more easily penetrate the thin insulation of windows and doors. So, for a constant level of heating (at night**), if all the house were covered in the glass windows with the red (hot) appearance, then more heat would be lost from inside. Conversely, if there were no windows or doors all the outside would be the cold blue and less heat would be lost.
So, if the house is “warmer” to the view, then more heat is being lost – so tending to make it colder inside. Whereas if the outside is “cooler” then less heat is being lost tending to make inside warmer. So warmer is cooler!
** Obviously, in a real house, the windows also allow sunshine in, but for the sake of this analogy we are ignoring sunshine.
Problem with greenhouse gas warming.
Yesterday I introduced a summary of the way greenhouse gases actually work rather than the way we are told they work. Normally we are told CO2 absorbs IR and so:
more CO2 causes more heat to be trapped
But anything that absorbs also emits and so it is just as true to say that because CO2 emits IR:
more CO2 causes more heat to be emitted
Obviously, this makes the “standard” explanation of CO2 warming a complete load of non-science and I have a lot of sympathy with those who dismiss it as such.
Recap of actual greenhouse warming.
A semi-transparent atmosphere
To recap my post yesterday “The CO2 Greenhouse effect is real (sometimes)“, if we consider a transparent atmosphere. Being transparent it has no effect on incoming or outgoing radiation. So all the surface radiation reaches space and the radiation power reaching space is purely dependent on the surface temperature (and emissivity).
If however, we interpose a thin layer of gas which is semi-transparent, it interferes with a small fraction of that radiation. Let us suppose this fraction were 1%. That would mean that 99% of the radiation would pass through without being affected. But 1% would be absorbed and 1% emitted.
This fulfils the basic requirement of physics which is normally contradicting by those explaining “greenhouse warming”. If anything is able to absorb IR it must also be able to emit it.
(For the purpose of this post, I am ignoring the fact that CO2 behaves differently at different wavelengths. This is because I do not try to quantify the greenhouse effect. So whether it is 1% or 0.0001% the direction is the same.)
So, when there is a semi-transparent layer with interacts with 1% of radiation, looking from outside (like the house photo above), 99% of what we see is the surface at around 15C, but 1% is this thin layer. And if this thin layer is colder there is less radiative emission (but if it were warming there would be more)
To give an example with the house. Think of an old style house with solid brick walls. On a cold day, the outside might be perhaps 2C above ambient. If however, we add an insulating coat to the house, the effect is to stop heat reaching the outside, so now there is less heat to warm the outer surface of the house and it now only reaches 1C above ambient. So, for a house at a constant temperature,
a house with an outer surface which insulates is cooler and emits less radiation.
turning around, for a house with constant input of heat (equivalent to a planet with constant solar heating):-
A house where the outside surface is cooler is hotter inside
(for the same level of heating)
Skydragons
One of the key arguments against the greenhouse effect I’ve seen put is from those sometimes referred to as “skydragons”. And this argument I think really boils down to this:
the scale of the purported greenhouse effect is very similar in scale to that of the adiabatic effect – so the higher temperature of the earth is due to this.
This gives us two very contrasting views:
- Consensus science: the greenhouse effect can be calculated so it is real therefore the adiabatic effect has nothing to do with the higher temperature of planets like earth.
- Skydragons: The adiabatic effect is real physics, and therefore it is the greenhouse gas theory that must be wrong.
I would now like to propose a solution that I think bridges this gap and means that both are right (at least in significant parts).
Recap: Calculation of total greenhouse effect
Model of earth
As we have been told too many times, the temperature of the earth is determined by the balance between incoming and outgoing radiation.
[Note: this section is only showing how the greenhouse effect is usually calculated. Before jumping to comment please note the end where I say: “the theoretical value when we take a real earth with varying temperatures is considerably different.“]
Incoming radiation
As the diagram to right shows. Sunlight falls on only one side of the earth (daylight) so if the fraction of reflectance or albedo is A, the solar energy per unit area S, Es is the total solar (shortwave) energy collected by the planet per unit time (in units of W), the amount of sunlight absorbed is:
Es= (1-A) SπR2
Outgoing radiation is emitted from the entire surface. According to the Stefan-Boltzman law the power emitted is proportional to the fourth power of its temperature. So emitted heat energy is given by:
Ep= 4πR2 σT4
Where Ep is the planetary (longwave) radiation (in W) and σ is the Stefan-Boltzman constant.
The temperature increases until a radiative balance is reached when EP=Es so:
4πR2 σT4 = (1-A) S πR2
rearranging and eliminating terms we obtain:
T= ((1-A) S / 4σ)-1/4
| For the earth | S is about 1368 Wm-2 |
| σ is 5.6704 10-8 | |
| A of about 0.3 |
And this leads to a value of -18C as the theoretical temperature of a sphere the size of the earth, with the same distance from the sun and at a uniform temperature.
Because the actual average surface temperature is around 15C, this difference of 33C is taken to be the “greenhouse effect” of the atmosphere.
But As Gerhard Gerlich points out in Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics the theoretical value when we take a real earth with varying temperatures is considerably different.
Adiabatic heating
Pressure pushing down causes heat to rise.
Anyone who has done science, should be familiar with the concept that compressing a gas causes the temperature to rise. If not, find a bicycle pump, hold your thumb on the end and press down a few times, with sufficient pressure to let out a little air. Very soon it is soon hot to touch. This is compressive heating!
It’s easy to think of this as “more energy in a smaller space”. However the actual reason is that work is being done compressing the gas and this work raises the energy and so temperature.
Likewise, but in the opposite direction, when air rises, it expands, it does work on its surroundings and this loses energy and this time it’s temperature drops.
Adiabatic Lapse Rate
As air in the atmosphere warms and expands, it rises and cools. The declining temperature with altitude is called the ‘lapse rate’. The adiabatic lapse rate (Γ) refers to the change in temperature (dT) of a parcel of atmosphere as it moves up or down (dz) without exchanging heat with its surroundings. It is governed by the planet’s gravitational force (g) and the specific heat (cp) of the atmospheric gases. Earth’s theoretical lapse rate is calculated as:
Γd = – dT/dz = g/cp
This varies, but for the region of atmosphere below the stratosphere where convection dominates as a process, the temperature drop is around 6.5 C km-1
Somewhere I saw a “skydragon” calculation that purports to show that all the adiabatic cooling is the same size as the greenhouse. However, whilst I cannot give a working for them being equal, there are numerous posts talking about the way venus is hotter because of the much more extensive atmosphere and therefore larger adiabatic effect as the higher pressure “heats” the atmosphere
Taming the “skydragons”?
Unfortunately, because “skydragons” have been led to state that the greenhouse warming effect does not exist, this has resulted in a sharp division between the two schools of thought.
However, I now think I have found a way to resolve this dilemma: the two very different calculations, each providing a very big number (of many degrees) neither of which seems to admit the other exists.
I would now like to suggest that the greenhouse effect and the adiabatic effect are in fact two facets of the same thing. To see how this can be possible let’s examine the two big problems.
- The adiabatic effect explains why the surface surface is warming thermodynamically. What it fails to explain is how this warmer atmosphere is connected to the heat sink of space.
- The greenhouse theory explains why the atmosphere is warmer (because it effectively traps heat), but in its normally stated form it fails to explain how “greenhouse” gases, which both emit and absorb IR radiation can act to trap radiation.
Now, using my simple conceptual model we may be able to bridge the two because in my model I show that the greenhouse effect is caused by the cooler atmosphere. So:
it is the temperature of the atmosphere which drives the greenhouse effect.
Greenhouse gases: a tap between adiabatic heating and IR
fractional distillation
To explain how CO2 and temperature interact, I would like to use the idea of a fractional distillation column.
To the left is such a column for the separation of oil into various fractions.
The temperature varies from the bottom to the top. Hot gases rise up the column cooling as they go until they condense, and then cooler liquid flows down. This way the most dense and least easily evaporated fractions like bitumen tend to collect at the bottom. Then as we go higher we go through successively lighter fractions (ship oil, diesel and aircraft fuels) until we get to car petrol and finally the bottled gases.
Now let us imagine, that this column has been bubbling away for time enough that all the fractions have separated. But none of the taps out the side are open.
What happens if we then open one tap?
That particular fraction is extracted and if there were only one outlet pipe, for the time that that fraction still has any liquid the whole process would be seen as:
oil → fraction
That is, for the time that fraction’s tap is open only one goes through the process. Tapping the process at one
But now imagine that rather than oil, what is going in is heat. And that unlike oil which can only be in one form, the heat can increase and decrease in temperature as heat flows up and down the column. So, tapping at any point can be a continuous process as new heat flows in.
Now, we have a process whereby opening up one tap at a particular level.
Temperature input → fractional temperature
What greenhouse gases like CO2 are effectively doing is to be the “tap” that connects between the fractional temperature (the adiabatically controlled temperature column of the atmosphere) and IR radiation, They are in effect “tapping” the column and “releasing” it to space.
But, just as within the fractional column, gas is constantly moving up and liquid moving down so that heavier fractions move down and lighter up throughout the column, so in the atmosphere, temperature is both being emitted and absorbed at all levels.
The adiabatic cooling curve controls the temperature of the column and the greenhouses gases control the rate at which this temperature is “tapped” into the IR.
So, if we were to observe the earth from outside, what we would see is a combination of all the “taps” within the atmosphere. But in wavelengths where most of the IR radiation is being absorbed and re-emitted we tend to see the “fractional” temperature from the top of the “adiabatic column”. This is why the adiabatic cooling temperature comes out as the greenhouse temperature.
The greenhouse gas is the sum of the adiabatic temperature of the atmosphere at the levels at which the greenhouse gases operate
So, greenhouse gases, are not so much “trapping” heat, as acting by “tapping” heat. They are acting as a vector (tap) enabling the flow of energy between the adiabatic column and the IR radiation that eventually leaves the atmosphere. And it is because the adiabatic cooling reduces the temperature, that the apparent temperature of earth from space is cooled which in turn (remember a cooler surface causes internal warming) causes the planet to be warmer.
Depending where the “greenhouse tap” has most effect, this tends to cool or heat the atmosphere. So the introduction of “greenhouse gases” tend to increase the flow between radiative and stored heat which tends to mean that the higher taps “mask” the lower ones. This tends to expose higher elements up the adiabatic cooling column, so changing the effective temperature of the earth seen from space.
So, adiabatic cooling and greenhouse cooling are just two facets of the same physical process that warms the earth.
Left is the temperature profile of atmosphere as a result of adiabatic cooling and similar processes. This connects to the radiation “column” via greenhouse gases such as CO2 (and more importantly water vapour). Thus the outgoing radiation temperature is largely determined by the atmospheric temperature at the places where greenhouse gases act as a conduit between the heat in the atmosphere and the radiative heat.
Reblogged this on Tallbloke's Talkshop and commented:
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OK, Have at it. 🙂
Wow, I mean an Earth that is spherical and only gets sunlight on one half of it during the day … revolutionary.
Here is a similar model with a little more detail achieving the 33C and -15C values without any greenhouse effect …
http://climateofsophistry.com/2012/11/07/the-fraud-of-the-atmospheric-greenhouse-effect-part-3-in-pictures/
The real question is that does the composition of a planetary atmosphere effect the ambient temperature of that atmosphere? I think that you are saying that the answer is “no”. However the composition of a planetary atmosphere may affect the way that energy flows within that atmosphere.
Vapour makes a difference because vapour has a much greater mass density that a free flowing gas. When vapour forms clouds, there is also a radiative effect that can be measured in both directions (upwelling and downwelling).
Okay. Lemme see.
The increase in GHG causes an increase in the lapse rate while also increasing the retained energy capacity of the atmosphere, holding it as heat (seen as temperature),
So warmer at the bottom of the atmosphere but the atmosphere cools faster with height. While temps at the surface are higher, AT WHATEVER ALTITUDE WHERE YOU PREVIOUSLY MEASURED THE TEMPERATURE, the (new) temps are lower.
Lapse rates are not linear with respect to GHGs. The non-linear lapse rate prevents a runaway heating event.
Do you agree with Dr Evans hypothesis of atmospheric “pipes” and the RATs multiplier which I have pasted below? If nosy, why?
“Three Pipes
The output of the low pass filter is the temperature of the surface of the Earth that radiates directly to space. This “radiating surface” is a virtual surface, consisting of different physical surfaces at different electromagnetic frequencies of radiation.
At the electromagnetic frequencies that are absorbed and emitted by carbon dioxide, the surface of the Earth is at the “one optical depth” of the carbon dioxide, where an observer from space is looking through sufficient carbon dioxide that they cannot “see” below that layer, on average. The carbon dioxide emissions layer is about 8 km up in the atmosphere at the tropics. It is effectively where all emissions from Earth direct to space at the carbon dioxide frequencies occur, because, on average, emissions below this layer are absorbed by the carbon dioxide (space cannot see those emitting carbon dioxide molecules, so they cannot see space).
…
At the emissions and absorption frequencies of water vapor (which is the main greenhouse gas), the emissions layer is on average about 10 km up in the atmosphere at the tropics.
There are also other emissions layers for other greenhouse gases, but in this simple analysis we’ll ignore them because their effect is small.
…..”
http://joannenova.com.au/2014/06/big-news-part-v-escaping-heat-the-three-pipes-theory-and-the-rats-multiplier/
If not, why?
I understand that some people disagree with the use of the word “filter”. This the way that I think of the filter, if I lay in the sun and a cloud goes over, I get cold so the cloud is “filtering” the frequencies that make me warm at the same time the cloud is gaining energy.
As day turns to night the cloud is a “warm blanket” between the earth and space. The earth radiates it’s energy during the evening but it radiates it energy more slowly because the cloud acts as an insulator.
Overall, I agree with the train of thought. A “Greenhouse Effect” that warms the surface requires a lapse rate that cools as you go up from the surface. The energy in the 15 um band would have escaped directly and easily to space. With CO2, this energy gets shunted into the atmosphere and only “tapped” at some higher colder level, where it radiates less effectively.
But really you are just explaining “the greenhouse effect” as it is understood by people with a moderate level of understanding. Phrases like “CO2 traps heat” are junior high level explanations — highly simplified, but not “a complete load of non-science”. (That would be sort of like complaining about teaching a phrase like “the earth circles the sun” because the path is an ellipse, not a true circle.) All of the more advanced explanations (like yours here) requires a lapse rate. That IS part of the model, even if it is not explicitly stated on all the websites aimed at the general public.
One specific critique — you said:
“for a house with constant input of heat (equivalent to a planet with constant solar heating):-
A house where the outside surface is cooler is hotter inside (for the same level of heating)
The outside surface must be (in some average sense) the same temperature if the power is kept constant. Consider two identical boxes with identical heaters, but one box has an extra layer of insulation on the inside. The outsides of the two boxes will be the SAME temperature (to shed the same total power), but the interior will of course be warmer in the insulated box.
Perhaps you were getting back to the idea that if you insulate PART of the exterior (like the walls), then that part will become cooler, while other parts of the exterior (like the windows) get warmer. And the interior gets warmer as well.
That equation you quote is a mathematical abstraction that does not represent reality owing to the fact that the surfaces of rocky bodies are not at uniform temperatures (this would require “Thermal Superconductors”).
QUOTE
The temperature increases until a radiative balance is reached when EP=Es so:
4πR2 σT4 = (1-A) S πR2
UNQUOTE
If one wants to represent reality one must include more realistic assumptions about the thermal properties of rocky bodies as I attempted to do here:
http://tallbloke.wordpress.com/2014/04/18/a-new-lunar-thermal-model-based-on-finite-element-analysis-of-regolith-physical-properties/
Please note that the lunar equatorial temperatures calculated using Finite Element Analysis are in close agreement with the Diviner LRE measurements.
I recommend ducking below any solid parapet.
Mike writes –
“So, if the house is “warmer” to the view, then more heat is being lost – so tending to make it colder inside. Whereas if the outside is “cooler” then less heat is being lost tending to make inside warmer. So warmer is cooler!”
NO. NO. NO. An object that cools less, is warmer than it would have been if it had cooled more. A completely different meaning.
I have not had time to read this thread yet, but I will, and I will point out any strawman arguments that may have been inadvertently used…..
Given the article started with the above quoted misrepresentation then I suspect there will be some….
Quick note –
“Recap: Calculation of total greenhouse effect”
PLEASE, PLEASE, earth is NOT a black body, STOP treating it as such.
“The real question is that does the composition of a planetary atmosphere effect the ambient temperature of that atmosphere?”
Looking at the last diagram:
On the left if the temperature profile caused by the composition of planetary atmosphere, on the right is the greenhouse effect it causes.
The pipes are those funny “pipe” looking things connecting between the atmospheric temperature profile of the left and the radiative profile on the right.
And it is because the atmosphere is lower in temperature that we get the greenhouse effect (note – warmer=cooler in first paragraph)
If yes – why did you ask the question?
The cloud creates a stronger connection between the earth’s temperature profile and the greenhouse effect / radiation flow.
Because the connection is greater, the outgoing radiation is cooler (from the cloud layer) so because “cooler=warmer”, there is more greenhouse effect.
‘But really you are just explaining “the greenhouse effect” as it is understood by people with a moderate level of understanding.’
I’m glad you said that. The model is now so in sympathy with the “skydragons”, that I was starting to feel like one. This supports what I’m saying that the “sky dragons” do just seem to be restating the greenhouse gas theory – which contradicts the “mickey mouse” version we get told about blanketing, but not the one “understood by people with a moderate level of understanding.”
“The outside surface must be (in some average sense) the same temperature if the power is kept constant.”
Yes you are probably right – but to avoid a long discussion about heat loss mechanisms in housing I didn’t make any specific claim about what happened. Working out planetary insulation is child’s play compared to housing. Planets=radiation. Housing = radiation, convection, conduction (ground), draughts, kids leaving doors open.
I was just doing a brief recap of the traditional calculation. After which I specifically address your point where It says:
“But As Gerhard Gerlich points out in Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics the theoretical value when we take a real earth with varying temperatures is considerably different.”
I was having fun mixing about the two perspectives – one of the temperature inside and the other of the surface temperature as viewed from outside.
I remember when I was doing IR detectors for people, many of my colleagues refused to admit that putting on a coat meant it was harder to spot the person and that most of the radiation from a person comes from their head (the coldest bit of them).
It was only when I showed them a thermal picture of a person with glowing hands and head (the cold bits) that they finally agreed with me, that a coat which made them warmer, was making them look colder.
Derek – when explaining how people usually work out the level of the greenhouse effect using the blackbody approximation — I think I do need to use the blackbody approximation to show how that is done.
Also, if you want to criticise anything it’s the “transparent atmosphere”. Come on! That’s the biggest lot of rubbish I’ve ever written – an atmosphere of totally inert gas!
And I did flag up problems very clearly: “But As Gerhard Gerlich points out in Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics the theoretical value when we take a real earth with varying temperatures is considerably different.”
As for approximations in general … the earth is also not a sphere. Our weight is not constant. Sea level is not constant. Planetary plates are moving.
Do you have a road Atlas – which is only an approximation to reality (roads on atlases can be 2-3x bigger than reality to make them prominent enough to see) – or do you always use an aerial photograph, which is damn near impossible to navigate with (roads get hidden by trees) or perhaps you are so dismissive of any approximation that you don’t use any approximation of reality at all?
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Sorry, but this article is wrong. You have got the most basic physics wrong. The fundamental assumption of Atmospheric Science about the (enhanced) GHE, dating from Sagan and Pollock in 1965, is that the Earth’s surface emits IR as if it were a black body in a vacuum in radiative equilibrium with a sink at absolute zero.
This is completely wrong. I can easily show why. Your analysis of the ‘flat plate’ absorber and of the rest is based on Hansen et al’s ideas from their 1981 paper. It should never have passed peer review. This is because they mistook irradiance, the potential EM flux from a warm body as expressed by the S-B equation, with a real flux. They also assumed there is a single IR emitter in the upper atmosphere at -18 deg C. There are in fact three, and the -18 deg C is the flux weighted virtual mean.
Net energy transfer at a plane is the vector sum of irradiances. The emissivity of the lower atmosphere near the surface is ~0.6 on average. This means that the mean operational emissivity of the surface is (1-0.6) = 0.4, for 16 deg C mean surface temperature, 158.4 W/m^2 maximum net IR; the experimental value is 160 W/m^2. Because there is parallel convection and evapo-transpiration, this falls to the 2009 Energy budget 63 W/m^2, an operational emissivity of 0.16 with 97 W/m^2 conduction plus evapo-transpiration.
16 deg C is the present equilibrium temperature. As the no cloud or ice temperature would be 4 to 5 deg C, present GHE is ~11 K. At the last glacial maximum it was ~2 K. Atmospheric processes mean CO2-AGW is near zero. There can be no gas phase thermalisation of GHG-absorbed IR, otherwise Kirchhoff’s Law of Radiation would be breached.
The enhanced GHE is bad physics designed to appeal to people with little Radiative or IR physics’ knowledge.
Sorry, left out the most important bit; the operational surface emissivity is 0.4 because the net IR emission in all self-absorbing GHG IR bands is zero.
Yes; there is zero CO2 15 micron net IR emission and the same for most H2O bands. This is why there GHG-absorption and back radiation ideas are totally wrong. Not only is there very little to absorb (the 23 W/m^2 in the non self-absorbed H2O bands), it can’t thermalise in the gas phase. ‘Back Radiation’, defining an atmospheric IR impedance, is small to vanishingly small.
Furthermore, the whole idea of ‘Forcing’ is Physics’ Tosh for IR: increased atmospheric irradiance reduces net surface IR emission. You can use the Forcing concept for SW but only because the surface temperature is very small compared with the Sun’s so the vector sum of irradiances is effectively the Sun’s irradiance.
Until the IPCC accepts it has got all heat generation and transfer wrong, it will continue to cheat (applying Kirchhoff’s Law of Radiation at ToA, impossible for a semi-transparent atmosphere, then using ~30% high low level cloud albedo in hind-casting).
Alec, your post is interesting but unfortunately irrelevant because I’m not making an argument for this calculation of 33C only showing how it is normally done.
So, I’ve now amended the article to make it clearer that I am reproducing the typical way the greenhouse warming level is calculated. Hopefully, people will then read to the end of even that section.
1) -18 deg C is the flux-weighted virtual mean of 15 deg C surface atmospheric window IR, -50 deg C CO2, lower stratosphere and mean -1.5 deg C from ~2.6 km H2O (~5 deg C to -30 deg C (cirrus cloud height)). It doesn’t exist: 33 K GHE is incorrect; Lapse Rate has nothing to do with the real GHE.
2) 11 K, is an approximation; Lindzen has considered ~16 K. It is set by clouds because atmospheric processes reduce the GHE from well mixed GHGs to near zero, as is being proved empirically. The increase of the GHE in the 1980s and 1990s, the real AGW, was from Asian industrialisation reducing cloud albedo**. This was picked up as a reduction of area because of the way lower clouds are measured by satellite image processing.
3) Sorry, shouldn’t have said wrong, just misguided by assuming Hansen et al 1981 is correct. That paper should never have passed peer review because it assumes without evidence a single upper atmosphere IR emission zone to Space. There is another bad error showing they hadn’t thought out the problem properly.
**Carl Sagan got aerosol optical physics badly wrong by assuming one optical process when there are two; the real AIE has the opposite sign. In short, clouds with bimodal droplet size distributions have higher albedo. This was quantified in 2010 by cloud physicist G L Stephens – he has not apparently been allowed to publish his findings. My paper was rejected instantly by Nature ‘Climate Change’ ‘because the mathematics would be too difficult for our readership’!
Perhaps I ought to be a bit humbler……..
However, the 33 K GHE is and always has been a confidence trick based on a completely unjustified assertion in 1981_Hansen_etal.pdf which doesn’t fool anybody with my background (process engineering plus a physics’ PhD).
I have checked this with such people around the World. 100 years of process engineering literature shows that the real net IR emission from a surface in coupled convection and radiation is much less than the black body level.
For 0.9 emissivity hot rolled steel, net radiation only exceeds natural convection at ~100 deg C. For hot-rolled Al it’s about 300 deg C. I spent some time developing with others the first two-colour optical pyrometer to measure the temperature of hot mill Al strip so i do l know a bit about it……! This failure in Atmospheric physics is 49 years old.
PS you can prove all this net IR stuff using MODTRAN which has hard coded in it the ~160 W energy flux from surface to atmosphere. The programme calculates irradiances at any plane in the atmosphere. the difference of Irradiances at the surface gives the net heat transfer. For a temperate medium humidity atmosphere at 16 deg C, you get the 160 W/m^2.
One minor problem is that all the so-called sky dragons should not be lumped together. Most of them have different qualifications and experiences. Prof Claes Johnson was one of the originals. He is a very knowledgeable mathematician as was Fourier (who was one of the first to write about heat transfer) Prof Johnson proposed a mathematical solution to the 2nd Law of Thermodynamics and his contribution to the Sky Dragons was to state and show that there is no back radiation. Many engineers (at least those who have had actual industrial and experimental experience with heat transfer) agree with that.
Prof Claes Johnson has been informed that he is to be awarded the Ludwig Prandtl medal for showing with computational mathematics that Prandtl’s models and equations of aerodynamics was incorrect. He has shown that the actual lift of aerofoils can be modeled by using the Navier-Stokes equation. I have a feeling in time he will be acknowledged for his mathematical contribution to heat transfer.
Trenberth’s global budget relies on a concept of back radiation from “greenhouse” gases. That becomes nonsense when it is considered that back radiation is “Non Physical”.
Another one of the Sky Dragons (I think a Professor in Mexico) has made calculations using Prof Hoyt Hottel’s concept of path length and partial pressures to show that the radiation absorptivity of CO2 in the atmosphere upto 8km is insignificant. I have done that also using the equation in Chap 5 of Perry’s Chemical Engineering Handbook. It is actually convection and condensation of water vapour that changes the lapse rate from adiabatic (9.8C/km) to the environmental rate (of 6.5C/km). CO2 radiates at the top of the atmosphere to space at about 220K but most of the radiation to space comes from the surface via the radiation “window” and from the top of clouds. Clouds also reflect in coming radiation from the sun.
The only greenhouse gas that is important is water vapour because that forms clouds which control the flow of heat to and from the planet.
Incoming radiation: “the amount of sunlight absorbed is: Es= (1-A) SπR2
No. That is the ammount _falling_ on the Earth, not the ammount absorbed.
The Earth is spherical, so angle of incidence matters.
(I know you’re just reciting the standard narrative for illustration, but it needs criticism.)
I know the feeling – you see something interesting and then see some daft assertion which has no merit – and then go into overdrive.
What I can see is any “model” is just a vast oversimplification of the system. The question then is how to simplify the system in a way that is still meaningful AND allows a transition from the least complex model “Noddy greenhouse warming” through to more complex models.
The question then is whether the model of the “thin layer viewed from outside” and the final “fractional column” might provide a way to allow people to transition from the Noddy theory of greenhouse warming through to the more complex ideas that you have.
Sleepalot says: July 4, 2014 at 2:54 pm
TOP POST > Incoming radiation: “the amount of sunlight absorbed is: Es= (1-A) SπR2
Sleepalot >No. That is the ammount _falling_ on the Earth, not the ammount absorbed.
No, the amount falling on the earth is SπR2.
The amount reflected is A SπR2.
The difference is the amount absorbed, which was correctly given as (1-A) SπR2
I think the best analogy that applies here – is that when a car is stuck in the mud, having detailed conversations about your destination and were to stay is rather irrelevant until you get out the mud.
The immediate question is how to get out the mud … how to start getting people to think of climate in new ways … to “wean them off” the current model.
All I can say is that when I started to view climate with the above model, I began to see how radiative “trapping” was in fact connected to adiabatic cooling. And once I saw that atmospheric temperature was driving the greenhouse effect with CO2 (and other such gases) acting as a vector connecting the two, I began to see how the skydragons ideas were not actually in contradiction to the standard greenhouse warming model.
When I asked this question on JoNova this is the answer I received. Is the “qdot” formula correct? (So much to learn, so little time)
Author: Greg Goodman
Comment:
:
So you think a molecule has to check with the future to see what the final destination of the radiation is going to be before deciding how much to emit.
Author: Greg Goodman
Comment:
“…the real physics: qdot = – DIV Fv where qdot is the monochromatic heating of matter per unit volume and Fv is the monochromatic radiation flux density.”
How does – DIV Fv vary in the presence of cloud?
Sorry, I rushed out the last reply and didn’t properly read about the “pipes”.
What I’m saying is that radiative “heat” and atmospheric gas “heat”, are connected by greenhouse gases which act as vectors, conduits or “pipes” to connect the two.
Any molecule which is at all opaque is a potential vector or “pipe” between the radiative and gaseous heat.
This link is strongest where it is most opaque. Clouds are very opaque and therefore they form a strong link between the radiative heat flow and the gaseous heat.
Also, dense regions of “pipes” will have very little flow because rather like a commuter in a traffic queue they don’t move far before stopping. However, when they eventually reach open road … zoom … the flow after the queue ends is largely determined by the rate at which cars leave the end of the queue.
The “three pipes model” is really just a description of three distinct “ends of queues”.
Also, within the “advanced greenhouse model” I describe, these “pipes”, have no directionality. Heat will flow into CO2 and then to emissions in all directions, just as easily as radiative heat will find a CO2 pipe and flow in.
Scottish Sceptic says
“The immediate question is how to get out the mud … how to start getting people to think of climate in new ways … to “wean them off” the current model. “
I would say that differently. You are not weaning them off the “current model”; you are weaning them off the “simplified, junior high level model that is often presented to the general public” and exposing them to a more complete version with deeper scientific understanding. You are leading TOWARD the current model, not AWAY from it!
That’s a good way to put it.
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I don’t have the math to debate you. If you ignore angle of incidence your model is of a flat Earht.
I don’t ignore angle of incidence. My model is integrating over the surface of a spherical earth.
Bait and switch. I criticised the standard model (given above). You defended that model
(with math that does not support your claim). Since you defended that model (thereby associating yourself with it), I referred to it as your model. Now you reply that your model has different properties. A very effective troll – hope you enjoyed wasting my time.
But is that proof that not having CO2 in the atmosphere would make any temperature difference? Not having CO2 in the atmosphere may affect the way energy flows, but not the overall magnatude of the energy levels over time.
The big difference between the Advanced Greenhouse Theory I propose and the Basic one, is that in the advanced one, the radiation (both up and down +side) is determined by the temperature of the atmosphere, (rather than radiation determining temperature).
In general, a molecule which interacts with IR in a colder atmosphere, will absorb more energy than it emits. This is what the Basic theory means by “trapping IR”.
However, if you have a relatively warmer part of the atmosphere above a colder part, then paradoxically, increasing CO2 could cause the “apparent temperature” as viewed from space to be more like the warmer part. So, because the apparent temperature is higher, the IR radiation outward increases and in that case, more CO2 would cause “GLOBAL COOLING”.
However, that all depends on what happens to the heat once it gets into the atmosphere. If it is rapidly dispersed (or back radiated)… then we really get back to the the Basic Greenhouse Model. However, if you change the flow of IR into the atmosphere and that heat builds up or changes circulation so that there is now a different temperature profile, then the pattern of IR emissions and absorption change. That really isn’t included in the Basic Theory.
Then the question becomes “how does CO2 affect atmospheric heat flows” rather than the Basic theory which says things like “how much is back radiated”.
Heat flows are conductive, convective (and radiative but this is separated). The result of these is to create a temperature profile, and this together with the vectors connecting gaseous temperature to IR (& other) radiation is what gives us the radiation exiting the earth which determines if we have a radiative imbalance and either global warming or cooling.
–You are not weaning them off the “current model”; you are weaning them off the “simplified, junior high level model that is often presented to the general public” and exposing them to a more complete version with deeper scientific understanding. —
So eliminating the propaganda?
But we should keep in mind that Al Gore film was given to elementary school children, not junior high level.
I’ve been ranting for… I guess it’s a couple of years now, about the impossibility of having a surface emit as though it were a black body in a vacuum while it also undergoes convective and conductive losses.
Perhaps with the background to support the argument better you will have more luck than I did trying to explain this point, as it seems a rather big one to me, and apparently to you as well. Nice seeing someone who works in a field which heavily depends on this subject coming along and saying it rather than having to bring it up myself.
Last time I went on about it I wound up getting censored from various blogs, what can ya’ do though?
What’s most worrying is not that they use a simplistic model to explain to people what’s going on — but that seems to be the only model they have of what’s going on.
1) the “Standard model (given above)” is indeed of a round earth — there is even a diagram. I was not switching anything.
2) The model doesn’t even matter for the issue at hand, which was the equation Es= (1-A) SπR2! For ANY model, the total power falling on an object is (intensity of sunlight)*(cross-sectional area). The total power reflected is “A” times that result. The total power absorbed is (1-A) times that result.
For either a sphere or a disk, the cross-sectional area is πR^2
For either a sphere or a disk, the total power hitting the surface is S πR^2
For either a sphere or a disk, the total power hitting the surface is (1-A) S πR^2
Your initial claim is simply wrong. Your follow-up objection about “angle of incidences” is not germane.
edit: “very soon it is soon hot to touch” – too hot to touch (?)
“it’s temperature rises” -its temperature rises (it’s=it is)
Terminology note: The original “skydragons” meant the boogie-CO2 dragons, and their Slayers the debunkers thereof. So calling the “slayers” the “dragons” is polymorphically perverse.
Speculation: surfaces at the poles, and nightside, of slowly rotating Venus are kept within a degree or so of dayside equatorial temps by CO2 radiative short-circuiting. Convection and conduction are obviously not functioning to do so with 10 mph winds.
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