Guest essay by Paul Murphy
Here’s Wikipedia’s simplified but canonical description of the greenhouse effect:
The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases.
Solar radiation at the frequencies of visible light largely passes through the atmosphere to warm the planetary surface, which then emits this energy at the lower frequencies of infrared thermal radiation. Infrared radiation is absorbed by greenhouse gases, which in turn re-radiate much of the energy to the surface and lower atmosphere.
This greenhouse effect forms the basis for warmist doctrine: that human CO2 emissions are causing a catastrophic increase in the global average temperature.
Although people like Gaia theorist James Lovelock have predicted that global warming will kill billions of humans the belief that warming would be catastrophic for life on earth is largely unresearched and probably indefensible. There have been many extended warm periods in the earth’s history and the fossil records we have for them suggest that each produced more life, and a greater diversity of life, than the cooler periods preceeding them.
We have reasonable information, furthermore, on the Roman and Medieval warm periods and not only did each of these kick off significant civilizational development, but the polar bear made it through them embarrassingly undead and not a single estuarial or river basin culture, whether in Asia, Egypt, or Europe, is known to have drowned.
The Wikipedia article quoted above gives the two main facts warmism depends on: gases tend to emit heat at a lower frequency than they absorb it, and measured net solar radiation does not fully account for near surface air temperatures – but doesn’t directly raise the problem that the measured effect is roughly an order of magnitude too large to be accounted for by the known interactions between thermal radiation and atmospheric greenhouse gases other than water vapor.
This problem has produced a widespread search for a forcing multiplier – something which reacts to a small increase in atmospheric CO2 to force a big increase in atmospheric warming. So far, however, none of the candidates for this have withstood even friendly critical review – meaning that those who argue for CO2 as a primary source of a significant atmospheric greenhouse effect are committing themselves to the biggest magical hand wave since crystalline epicycles brought consensus to the Ptolemaic Universe.
The processes modeled in IPCC and related warmist calculations as this unknown climate sensitivity factor may exist in the real world – but every experimental effort to demonstrate that minor increases in atmospheric CO2 lead to major changes in surface temperature has failed to show a repeatable effect in anything near the right range:
- The biggest “experiment” on this is, of course, reality: CO2 concentrations appear to have gone up by more than 20% since 1958, but we have neither a clear definition of the average global surface temperature nor data to support the belief that any of the proxies we have for it have shown significant change over the period.
- The smallest and most often repeated experimental demonstration, the Al Gore tabletop special in which one jar contains a bit more CO2 than the other, produces essentially the same result if the same weight of an inert gas like argon is used in place of the CO2.
- It is easy to demonstrate the greenhouse effect by pointing a thermal imaging camera at the sky, but within the limits of Google and Bing searches it appears that no one mapping variations in the effect to variations in local concentrations of greenhouse gases other than water vapor and urban smog has demonstrated effects beyond the levels (roughly one tenth of the IPCC climate sensitivity assumptions) predicted by the theoretical calculation with no multiplier.
What we know of the earth’s climate history does not support the warmist indictment against anthropogenic CO2 emissions either: none of the warming periods recorded in human history can have been triggered by human CO2 production – and the longer term geological record seems directly contradictory too. Essentially all of the earth’s surface has been tropical at one time and glaciated at another, but nearly all of the information we have about the atmosphere during those periods suggests that CO2 concentrations rose during, but not before, tropical periods and fell significantly during, but not before, glaciations.
What we can say therefore about the belief that atmospheric CO2 increases are causing significant global warming is that it has no theoretical support, no experimental support, cannot be seen operating in the real world, and is contradicted by what we know of global climate history.
Where neither science nor history can explain warmism, politics can. Basically, if you’re someone like Al Gore whose political career is based on railing against American republicans, then an obvious reason for singling out CO2 as a threat to humanity’s future is that this is an easy sell: there is a grain of truth in the science, people can see smokestacks, the SUV is a widely approved target for angry rhetoric, and the political audience is generally eager to accept the burdens a demonstrated need to control national energy use would put on them.
Similarly, what we can say about the idea that global warming would necessarily prove net negative for life on earth is simply that this idea has not been extensively studied but seems to have neither theoretical nor experimental support and is contradicted by what we know about the history of life on earth, but meets the political need for players like Gore et al because people cannot be held hostage to the threat of a good thing happening if they don’t knuckle under.
It is important in forming personal beliefs about the relative roles of science and politics in warmism that we separate belief from reality: most of the alarmists seem to be true believers, most of the deniers merely Missouri skeptics, but there seems to be no objective evidence to suggest that either side genuinely knows whether the global climate is changing or not. Thus we can probably agree that the publicity now generally given a hot day in Death Valley and denied an extended cold emergency in Peru reflects an editorial agenda more than it does climate, but the combination of theory, data, and definitions we have is not sufficient to let us know whether either fell outside longer term climate norms.
The deeper issue here is not that the political action now strangling western economies is politically motivated, but that accepting the arguments for seeing warmism as sheer political fraud means accepting that the talking heads citing science to sell it to the masses are either deluded or dishonest – but because no wolf today doesn’t mean no wolf tomorrow, it also means that warmist politicization of the research process has to be seen as having destroyed the credibility of all involved, and thus as having greatly weakened the world’s ability to recognize and respond to a real threat should one now materialize.
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Paul Murphy, a Canadian, wrote and published The Unix Guide to Defenestration. Murphy is a 25-year veteran of the I.T. consulting industry, specializing in Unix and Unix-related management issues. This essay was originally written for consideration of the Matt Ridley prize.
I read through the comments here and many just don’t understand even the most basic aspects of greenhouse gases, the atmosphere, or radiative transfers. Each says a few things correct but then turn around and make mistakes along the way. The two that seem to have it mostly correct are Willis Eschenbach and Konrad, both are very close but a bit incomplete.
Konrad has proven experimentally that the greenhouse effect is real as Willis’s article claims. See his comment just above.
Take Willis’s “Steel Planet” example, what throws many is his example ends up with the radiation density at the surface as 470 W/m², far too high. All Willis needs is to add is “window radiation” that does not interact with the shell (our atmosphere). That’s all.
Let’s assume 40 W/m² is the window flux. Now that 40 goes directly through the shell to space without interaction and instead of 235 W/m² you just have 195 W/m² hitting the shell. Over time it equalizes and the shell radiates 195 outward plus the 40 is the same 235. But 195 also radiates downward making the surface equalize at 235 + 195 or 430 W/m². Still too high.
So let’s try 75 W/m² of window radiation. In that case the shell equalizes at 235 – 75 or 160 W/m². The OLR is still 235 W/m² lost to space but now only 160 is radiated downward making the surface radiative density 235 + 160 or 395 W/m² and those figures ARE what the satellites and surface measures are reporting on the average (or close).
See, it’s that portion of radiation at “window” frequencies that is so critical for it is really that portion that sets the surface temperature and according to Miskolczi’s research that factor is constant over the last some 60 years as co2 has been rising.
Some might say, well 75 W/m² is not the correct window radiation from the surface, and that seems true to the many papers trying to quantify that amount. Closer to 40 T-F-K says, but they also includes 30 W/m² from the clouds and that is in all essence the same as window radiation from the surface but with a momentary stop at the cloud. What is important is that this radiation also leaves through the tropopause without further absorptions so that portion also does not press backwards down on the surface overall and that give his estimate as 70 W/m².
There are some who do not even see the 160 W/m² from the inside of the shell actually warming the surface and that is actually correct, include me. What occurs is the downward impedes or is a two-way subtraction (could even view it as cancelling, as Poynting vectors, me also again) and the energy raising the 235 up to the 395 comes from the original energy source, for between the time of installing the shell until equilibrium is re-established the window is still occurring but very little is going through the shell allowing the radiative density at the surface to rise from the original 235 W/m² up to the 395 W/m² where everything balances again.
Also this did not take into account any, if it exists, directionality or any allowance for the curvature which may be two tiny adjustments needed.
Bottom line, Don’t forget the “Window Radiation” !! It is the one most important factor !! Let albedo be the variance.
So yes, Willis’s “Steel Shelled Planet” works as expected if you allow a portion of radiation to bypass the shell.
Jeff Glassman says:
November 5, 2013 at 8:27 pm
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Jeff,
the answer to your thought experiment is very easy. As I have previously shown through empirical experiment, the surface of the planet would not be greatly cooler under a non radiative atmosphere. So what would happen if our atmosphere contained no radiative gases?
1. The atmosphere would still be conductively heated by the surface.
2. Without radiative cooling of gases at altitude, tropospheric convective circulation in the Hadley, Ferrel and Polar cells would stall and the atmosphere would trend isothermal via gas conduction, with the bulk of the atmosphere (except for a near surface layer over land but not ocean) set by surface Tmax.
3. Atmospheric temperatures would then rise higher as stagnated poorly radiative gases such as N2 and O2 were subject to radiative super heating, just as they are in the thermosphere where molecular temperatures rise to hundreds of degrees.
4. Much of the atmosphere would then expand beyond the protection of the geomagnetic field and be swept into space by the solar wind.
5. Everyone’s breathing privileges would then be revoked.
I hope this answers your question 😉
PS. There are no planets or moons in our solar system that have managed to retain an atmosphere without some radiative gases in the mix.
Michel says:
November 6, 2013 at 12:21 am
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Nowhere do I claim that the planet cools by any other mechanism other than IR radiation to space. Not at WUWT, not at Climate Etc., not at JoNova, not at Dr. spencers site or any other site. Nowhere. If you have evidence of me making such a claim then present the evidence.
(Oh no, I’m starting to sound like Willis…)
wayne says:
November 6, 2013 at 2:36 am
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Wayne,
A slight clarification, the empirical experiment shown proves that the radiative physics behind Willis’ Steel Greenhouse is valid. However this does not prove that the net effect of radiative gases in our atmosphere is warming, in fact the six other experiments I have previously posted combined show that the net effect of radiative gases in our moving atmosphere is cooling at all concentrations above 0.0ppm.
The important words here are “net effect”
Konrad, oh I agree, no warming, net anyway. I think co2 will make next to zero net effect, that is why I included what Miskolczi discovered, the window is exactly as it was sixty years ago and since co2 has not affected it at all what slight warming came from something else, be it albedo changes, solar, both, it just was not co2 and Miskolczi lost his job with NASA over his research.
We might disagree on the finer ponits exactly why co2 doesn’t matter but I think we agree on the “net effect”. 😎
@Konrad November 6, 2013 at 3:28 am
OK, at least we have now this fixed.
Now infrared absorption: aren’t water, CO2, CH4, etc showing absorption lines in the IR spectrum?
At approx 15 °C the ground emits IR radiations into the atmosphere.
When looking at the figure at http://bit.ly/1gqZxAJ where will the absorbed energy (difference between blue and red line) going to, if not in adiabatic heating of the gas (the atmosphere) containing the IR absorbing components?
And if the concentration increases, the quantity of absorbed energy will also increase (a logarithmic dependency), and the temperature also.
This is the forcing that is being addressed in the CO2 story (not the convective heat trapping taking place in a glasshouse). And it has some relevance to the climate story, although in my opinion way less than claimed by warmists.
Willis Eschenbach, 11/5/13, 6:03 pm says,
I don’t understand your objection to saying that for a first cut analysis, the area of the surface and the shell are equal. They only differ, as you point out, by a tenth of one percent.
My problem was opening your discussion of the steel greenhouse with an appeal in good IPCC fashion to a problematic equilibrium when you could have used the solid principle of Conservation of Energy. In steady state, the energy emanating from the interior of your planet is the energy radiating to space from the exterior of the shell. Just to close on the idea, here’s the bookkeeping. The interior energy released is 235 W/m^2 times the area of the surface of the earth, 5.1006•10^8 km^2, which is 1.199•10^17 W. So the energy density radiated from the steel sphere is 1.1199•10^17 W/5.10545•10^8 km^2 = 234.78 W/m^2, adding 3 km to Earth’s radius for the shell radius.
You say,
The part you seem to be missing is that at steady-state, the shell will also be radiating 235 W/m2 back to the planet. This is added to the 235 W/m2 produced by the nuclear core. [¶] Remember that the shell has twice the surface area as the sphere. As a result, at steady-state, the surface of the planet is radiating at 470 W/m2 over an area A, and the shell is radiating at 235 W/m2 over an area of 2A.
and later,
Confuse heat and radiation? Where have I done that? Heat is the NET energy flow between two objects. Radiation is the individual energy flow either emitted or absorbed by an object. See? No confusion at all.
The where is in your addition of antiparallel radiation to attain 470 W/m^2. Heat and power are scalars, so if your planet, warmed by its interior, were inside a shell actively heated from outside to radiate to the surface, then the interior and active shell heats would add at the surface. Radiation, though, is a vector. It has a sign. Your shell being passive doesn’t add heat, so the outgoing radiation at your planet’s surface is + 235 – 235 W/m^2 = 0. The energy lost by radiation from the surface is just replaced by the back radiation from the shell. This net radiation is the radiant heat.
Your steel greenhouse is not a greenhouse (as that word is used for Earth’s atmosphere). It does not create a temperature drop from the planet surface to the outside surface of the shell, and for all practical purposes it does not change the OLR.
Congratulations on having your letter to Nature published.
Konrad: “3. Atmospheric temperatures would then rise higher as stagnated poorly radiative gases such as N2 and O2 were subject to radiative super heating, just as they are in the thermosphere where molecular temperatures rise to hundreds of degrees.”
I was with you until Step 3. Why would penetration down below thermosphere altitudes of the the high-energy radiation currently responsible, I’m told, for the “radiative super heating” no longer be suppressed by absorption in the (near-vacuum) thermosphere?
Also, could you please answer Mr. Eschenbach’s question, Cooler than what? That is, you seem to be saying that the radiative gases have a net cooling effect, but presumably you’re not saying that at the end of the day the atmosphere would in their absence disappear–and that as a result the earth’s surface temperature would on average be warmer than now. So what is the ultimate state of the atmosphere in your scenario in which the average surface temperature would be warmer?
seems to me the “average” earth temperature would be nearly the same with or without an atmosphere…just with wild swings daily but on average nearly the same? as in high of 80 and low of 50 averages to 65, high of 200 and lows of minus 70, still average out to 65….the atmosphere SLOWS the process eliminating the wild swings but NOT altering the total input/output of energy…….to make the system warmer REQUIRES more heat energy in total in the system, and the atmosphere doesnt do that.
Bill Taylor: “high of 80 and low of 50 averages to 65, high of 200 and lows of minus 70, still average out to 65”
Since radiation varies as the fourth power of temperature, wild swings would have to result in a lower average temperature than a constant, uniform temperature would. (You want the time average of the fourth power of temperature to remain the same over long periods, not the the time average of its first power.)
Willis Eschenbach says:
November 5, 2013 at 8:59 am
“Will, if you think that any of the science is incorrect that I’ve put forwards in my post entitled “The Steel Greenhouse“, I invite you to QUOTE MY EXACT WORDS FROM THAT POST that you disagree with, and tell us why you disagree.”
For the third attempt at posting this mods:
Willis,
using a thought experiment, the “Steel Greenhouse” as a means of verifying an hypothesis, the so called “GHE”!?
You could not possibly transit further from the principle of “science”.
An hypothesis requires empirical observation for verification.
When you use a thought experiment, where none of the main parameters are replicable, i.e. it is not possible to place a steel shell around a planet, in place of empirical observation, you are using a circular argument. A standard logical fallacy.
The flaw with the “Steel Greenhouse” thought is experiment is simple enough to unravel.
You cannot add 235 w/m2 to 235 w/m2 and come up with 470 w/m2.
235 w/m2 + 235 w/m2 = 235 w/m2
There is no increase in energy flux density so therefore there is no increase in temperature and thus no further increase in w/m2 above the original 235 w/m2.
Two ice cubes both radiating at 314.94 w/m2 cannot produce 629.88 w/m2 and melt each other. If you add one ice cube radiating at 314.94 w/m2 next to another ice cube radiating at 314.94 w/m2 you still only have 314.94 w/m2, QED.
Cheers
Will
my example was NOT a “constant uniform temperature”………wouldnt the same 4th power apply with or without an atmosphere? also the earth is NOT a black body.
wayne says:
November 6, 2013 at 2:36 am
Thanks for that correct analysis of the effect of the 40 W/m2 “atmospheric window”, Wayne. Curiously, rather than the radiation density being “far too high” as you say, it’s not high enough.
The problem is the balance at the surface. The average upwelling surface radiation is 390 W/m2. However, the surface also loses energy through both sensible and latent heat transport from the surface to the atmosphere. These total on the order of 100 W/m2.
That means that the surface is losing energy at the rate of about 490 W/m2 … and a perfect steel greenhouse only produces 450 W/m2 at the surface. So the problem is not too much energy … it’s too little energy to match the condition of the earth.
For that reason, the simplest model that can generate the energy needed to match the known energy losses in the form of radiation, and sensible, and latent transport has to have two shells. One shell doesn’t generate enough energy to allow for the temperature plus the losses. Here’s one two-shell possibility that fulfills those requirements …
Regards,
w.
Will Pratt says:
November 6, 2013 at 12:34 pm
So you’re saying that if I have a heater putting out a thousand watts per square metre pointed at an object, and then I add another heater of the same thousand W/m2 … your claim is that the object won’t warm any further because 1000 W/m2 + 1000 W/m2 = 1000 W/m2?
Really?
Because if so, my friend, you are beyond my poor ability to assist. Let me recommend the excellent post by ScienceOfDoom, which goes into the question in some detail.
Regards,
w.
Hi Willis. Yes, I was just using a single slab viewpoint and I also have found that the 70 W/m² from TFK is too low, you can never seem to get a balance with that value. I have broken your example into twenty to one hundred shells and on both Earth and Venus and you get some very interesting results. With a two slab model you can get some variance in what the ‘window’ radiation value is depending on at what average altitude those slabs represent. I have come up with, more than once, that it is close to 78-81 W/m² but once again that depends on the definitions of where the slabs are vertically and how many layers.
Willis, from your diagram I hope I’m interpreting you corrrect when you said “it is too low”.
If you take your ‘shell’ viewpoint and instead of tracking through distance which brings in lapse rates, varying pressure and density with altitude (distance) and all of the complexities they contain and instead break your ‘shells’ or layers into even and equal mass layers (really just even pressure breaks) on even other bodies it becomes so easy to get a relation all of the way from the surface to space and it is quite surprising. For really optical depth has absorbing mass at it’s core. You can configure the equations as distance and concentration or more simply just configure it as absorbing mass passed through and the later is much simpler. All of this stems from your “steel shelled planet” discussion and I must refrain going much deeper here for Dr. Brown is looking at that aspect right now on what this all seems to lead to.
Joe Born says:
November 6, 2013 at 6:23 am
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It the current debate about CO2, the whole atmosphere being poorly radiative is a theoretical problem only, as we would need to lose all oceans before this could ever happen. However as to theoretical radiative super heating of stagnant N2 and O2 in poorly radiative atmosphere, it is important to note that UV penetrates the full depth of our atmosphere and many meters into the oceans.
Willis’ question “cooler than what” is a fair question. The presence of liquid water on the planet makes this difficult. One cannot compare an “earth with atmosphere” to an “earth without an atmosphere”. Cloud albedo issues aside, without the pressure of an atmosphere the earth could not retain liquid oceans, nor could those oceans evaporatively cool.
One way to examine the role of non-condencing radiative gases in our atmosphere is to model their role in the atmosphere of a theoretical desert planet and ignoring solar wind and assuming diurnal cycle.
From coldest to hottest atmospheric temperatures –
Coldest – Thin atmosphere with radiative gases.
Cold – Thin atmosphere without radiative gases.
Warm – Thick atmosphere with radiative gases.
Hottest – Thick atmosphere without radiative gases.
Michel says:
November 6, 2013 at 4:28 am
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Again I will state that there is a slight radiative greenhouse effect, but the net effect of radiative gases in our atmosphere is cooling. Again, a planet in radiative equilibrium can have very different atmospheric temperatures depending on the energy flows, both radiative and mechanical, within the atmosphere.
Radiative gases act to heat the atmosphere and land surface in three main ways –
1. Interception and thermalisation of out going surface IR by in the lower atmosphere
2. Direct interception and thermalisation of incoming solar IR
3. Emitting downwelling IR slowing the cooling of the land surface in conductive contact with the lower atmosphere.
However radiative gases also act to cool our land surface, ocean and atmosphere by –
1. Radiating more than double the energy to space from the upper atmosphere than the combined net flux into the atmosphere from surface radiation and the incoming solar radiation directly intercepted by the atmosphere.
2. By cooling the upper atmosphere, radiative gases allow air mass subsidence, critical to tropospheric convective circulation. This strong vertical circulation across the pressure gradient of the atmosphere produces the observed lapse rate, lowering average tropospheric temperatures.
3. Tropospheric convective circulation so produced, acts to transport energy acquired from conduction and evaporation away from the surface.
The “basic physics” of the “settled science” of the original claims, modelled only the change in radiative exchange between surface and atmosphere for increasing radiative gases without simultaneously modelling the increased speed of tropospheric convective circulation that would result. They only modelled half the problem, and as the experiment I posted earlier with liquid water and incident IR shows, they even got that half wrong.
@Konrad
The “settled physics” remains so until unsettled by a better one, which in this case remains to be seen.
What is a “radiative gas” if not a substance that absorbs electromagnetic radiation at various frequencies determined by its molecular and atomic structure, for example oxygen and nitrogen in the UV range, water vapour and CO2 in the IR range. And by absorbing energy it gets warmed up.
It is tricky since the thermal forcing described as the cause of AGW is relatively tiny: for all gases confounded it is about 2.45 W m-2 as published by Myhre [1] since the beginning of the industrial era. It is only 0,7% of the average incoming sunlight of 341.5 W m-2 And any doubling of the CO2 concentration would cause a forcing of 3.7 w m-2, or 1.1% of the total (in comparison, the rainfalls that involve latent heat of vaporisation are accounting for approx 60 W m-2).
Are the experiments that you mention capable to grasp these quantities?
This forcing is small but is alleged to be relevant in the warming of the atmosphere: that’s where dissent begins between catastrophists, skeptics and heretics, in the size of its impact after taking into account feedbacks, not in the nature of the phenomenon.
[1] Myhre et al: “New estimates of radiative forcing due to well mixed greenhouse gases.”
Geophysical Research Letters, Vol. 25, No.14, pages 2715-2718, July 15, 1998
http://folk.uio.no/gunnarmy/paper/myhre_grl98.pdf .
Willis Eschenbach says: November 5, 2013 at 11:37 pm
“As a result, the system of planet and shell will only be at steady-state when the radiation outward from the shell is 235 W/m2.”
Absolutely not. The ‘shell’ only has the ‘total’ energy radiated from the planet’s ‘surface’. Thus, with ‘twice’ the ‘area’, can only radiate energy at ‘half’ the ‘W/m^2’ ‘energy/area, or power/area, flow rate’ supplied by the planet’s surface W/m^2 when in a thermodynamic ‘steady state’.
IMHO you seem to have confused a dynamic with a potential. Back-radiation increases the ‘potential’ (temperature, or energy density), but the rate of ‘total energy flow’ is constant, and equal, for both the shell’s and the planet’s ‘total surface areas’ when at steady state.
To propose that the outgoing W/m^2 is the same from the planet’s surface, as from the shell’s surface, is to propose a ‘perpetual refrigeration device’ for the space between planet and shell. It’s just impossible.
I think I’ve ‘talked this one to death’ elsewhere, and I’m unsure of its validity as thread content here.
Best regards, Ray Dart.
Willis – a heater is a heat source. A reflector is not. Am I missing something?
A short note to keep orders of magintudes in mind: Stefan Boltzmann equation E = ε σ T^4
A black body surface at 15 °C (288 K) emits 390.1 W m-2 with peak wavelength at 10.06 μm.
One degree higher at 16°C (289 K) it is 395.6 W m-2 with peak wavelength at 10.03 μm.
The difference is 5.5 W m-2
This is why small forcings matter.
Konrad:
“One way to examine the role of non-condencing radiative gases in our atmosphere is to model their role in the atmosphere of a theoretical desert planet and ignoring solar wind and assuming diurnal cycle.
“From coldest to hottest atmospheric temperatures:
“Coldest – Thin atmosphere with radiative gases.
“Cold – Thin atmosphere without radiative gases.
“Warm – Thick atmosphere with radiative gases.
“Hottest – Thick atmosphere without radiative gases.”
Thank you very much for the clarification. (The paragraphs preceding those just quoted made me fear that you were just going to drift off into irrelevancies.)
I now think I understand what it is that you believe. I think you’re wrong, but, since you appear to believe it strongly and I’m no physicist, I won’t attempt to persuade you otherwise. Still, I appreciate your giving a straight answer, which is a sometime thing.
Once again my reply to Willis has vanished into the ether.
Let me try once more:
Willis Eschenbach says:
November 6, 2013 at 1:33 pm
“So you’re saying that if I have a heater putting out a thousand watts per square metre pointed at an object, and then I add another heater of the same thousand W/m2 … your claim is that the object won’t warm any further because 1000 W/m2 + 1000 W/m2 = 1000 W/m2?”
It depends Willis. If you are in a vacuum, add as many heaters as you like.
If you are not in a vacuum, then because you have just added a second separate heat source generating another 1000 W/m2, then you have two separate energy sources both with temperatures of 364.4 K. So you can add more heat and increase radiation because you have increased kinetic energy. But this is not the same as adding radiation together. You cannot add radiation together and get more heat.
Remember the ice cube analogy I posted earlier Willis. That’s two ice cubes and therefore two lots of 314.94 W/m2 and yet no increase in temperature. Add as many ice cubes radiating 314.94 W/m2 as you like Willis, you know you won’t get more than 273 K.
If you were correct, which you are not, then ice would melt ice and there would be no such thing as ice. In-fact the only thing that would exist would be pure energy.
Keep off the “Science of Doom” wacky-backy Willis, it won’t help you understand reality.
Scalar v’s vector.
Michel says:
November 7, 2013 at 12:58 am
“What is a “radiative gas” if not a substance that absorbs electromagnetic radiation at various frequencies determined by its molecular and atomic structure, for example oxygen and nitrogen in the UV range, water vapour and CO2 in the IR range. And by absorbing energy it gets warmed up.”
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All true, but only half the picture. A radiative gas also emits IR. At the top of the troposphere radiative gases are emitting to space not just energy the atmosphere acquired by intercepting radiation, but energy acquired by surface conduction and release of latent heat from condensing water vapour.
It is this radiative energy loss from the upper atmosphere that allows subsidence of air masses in the Hadley, Ferrel and Polar tropospheric convection cells. Radiative gas concentration therefore plays a critical role in governing the speed of tropospheric circulation, and thereby the strength of mechanical energy transport away from the land and oceans.
Arrhenius made the mistake of not modelling this in 1896, and little has improved. You cannot use just SB equations to calculate changes in atmospheric temperatures for increasing radiative gases. Fluid dynamics is also required. The simplest way to demonstrate this is via empirical experiment.
Here is that simple experiment again –
http://i48.tinypic.com/124fry8.jpg
It’s simple to run. Just two 1m tall EPS foam boxes penetrated by thin aluminium heating and cooling tubes. 90C hot water run at the same flow rate through the heating tubes in each box and 1C water at the same flow rate through the cooling tubes of each box.
Q. Which box best represents an atmosphere with radiative gases and which a non radiative atmosphere?
Q. Which box will have the higher average gas temperature and why?
Q. Without adjusting water flow rates, how do you make the two boxes run at the same average gas temperature?
@Konrad
Of course by emitting in the IR range the substance will lose energy and in absence of other heat transfers (adiabatic conditions) will have its temperature declining.The major player here is water, the next one is CO2.
In your experience heat exchange is maintained with the exterior (running water in the coils). This is not the condition of the planet where the only heat sink is the outer space. Both boxes contain the same gases, “radiative” as you call or not. The final temperature will be driven by the running water exhanged with the air by conduction, convection and may be a little bit of radiation across the coil as long as there remains a driving force, a temperature gradient; any heat quantity is provided from outside the box. By the way, if the air in the box is saturated with water vapour the coil at 1 ℃ will cover itself with condensate the latent heat of which will be evacuated by the circulating water.
What apparently you don’t want to get is that the 2.45 W m-2 since the beginning of industrial age or the 3.7 W m-2 for a doubling of CO2 concentration relate to this IR absorbing phenomenon (a logarithmic concentration dependency), and are significant to the warming story where fractions of degrees are discussed.
IPCC now tells 1.5 to 4 ℃ on the basis of invalid or partial modelling, not on the basis of wrong fundamental phenomena.
The magnitude of that significance and the subsequent impact on the climate on our living conditions is the heart of the debate. And, at the cost of repeating myself, not the existence of the phenomenon.
Michel says:
November 7, 2013 at 11:59 pm
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Michel,
If you believe radiation plays any significant role in the experiment or the results can be confounded by any discussion of it then you simply don not understand the experiment. The experiment results are determined by Raleigh/Bernard circulation and conduction only.
Previously on this thread I indicated to you and future readers that –
“For a planet in where the outgoing radiation is equal to incoming radiation, very different land, ocean and atmospheric temperatures can exist depending on internal energy exchange below the top of the atmosphere. You seem to accept that changes in internal radiative fluxes can effect these temperatures, but ignore that changes in mechanical energy transport can also do this and that radiative gases play a critical role in governing the speed of convective circulation, a mechanical energy transport, below the tropopause.”
The experiment is a simple demonstration of the truth of that statement, designed so other readers can simply replicate it and confirm the results. (You know, the scientific method). The experiment when run for a period will result in both gas columns reaching an equilibrium state, with virtually the same energy entering and exiting each gas column. However the average gas temperature at this point will be higher in one column than the other. This is the direct result of the only difference between the two gas column, the height that energy is entering and exiting the gas column.
Once again, can you tell which gas column reaches the higher average temperature and why? You can imagine each column full of dry nitrogen if it helps.
Michel says:
Michel says:
November 7, 2013 at 11:59 pm
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Michel,
as to your further comment –
“The magnitude of that significance and the subsequent impact on the climate on our living conditions is the heart of the debate. And, at the cost of repeating myself, not the existence of the phenomenon”
– I would again say no, the “narrative” is collapsing and the is no longer any hope of controlling or framing the debate. I am aware that there are desperate attempts to find an exit strategy for all the activists, pseudo scientists, journalists and politician now hopelessly compromised, not just by their AGW advocacy, but by their shameless vilification of sceptics.
However “there is some warming but less than we thought because (insert “sciencey” sounding excuse here)”, won’t wash. In fact it just makes things worse. The net effect of radiative gases in our atmosphere is cooling at all concentrations above 0.0ppm. Avoiding admitting this is just holding scientific advancement back for sort term political expediency. Trying to engineer a “soft landing” for the fellow travellers is just adding to the permanent Internet record of wrong doing in this shameful assault on science and democracy.
The developing world is facing real pollution problems on a scale the developed world has never seen. Keeping AGW alive is destroying the last remaining credibility of environmental science and the environmental movement at a time when the planet can least afford it. Do the public careers of a few activists, journalists and politicians really matter in comparison?