David, thanks for elaborating on your thinking and questions on this topic. There is much uncertain and unknown about the functioning of our climate system. I listen when a seasoned expert such as John Christy says:
“The reason there is so much contention regarding “global warming” is relatively simple to understand: In climate change science we basically cannot prove anything about how the climate will change as a result of adding extra greenhouse gases to the atmosphere.
So we are left to argue about unprovable claims.”
http://www.centredaily.com/2014/03/20/4093680/john-r-christy-climate-science.html
So everyone is theorizing and wondering if and when the best theory will win–that is, become the new conventional wisdom. According to Christy, the science is far from settled, and he has examined the datasets extensively, having built some of them himself.
I have also learned a lot from Nullius in Verba, who is one of best explaining these things to us laymen. For example, he comments:
“It would be slightly more accurate to say that the lapse rate is the vertical temperature gradient at which convection switches off and therefore stops cooling the surface.
The sun warms the surface, but the heat escapes very quickly by convection so the build-up of heat near the surface is limited. In an incompressible atmosphere, it would *all* escape, and you’d get no surface warming. But because air is compressible, and because gases warm up when they’re compressed and cool down when allowed to expand, air circulating vertically by convection will warm and cool at a certain rate due to the changing atmospheric pressure. Air cools as it rises and expands, and warms as it descends and is compressed. This warming/cooling effect means that hot air no longer rises when it would cool faster from expansion than the surrounding air. Cold air can sit on top of warm air and be stable. The adiabatic lapse rate is why the tops of mountains are colder than their bottoms.
It’s a bit like the way a pot of boiling water sticks at a temperature of 100 C. If you turn the gas up, the water boils more vigorously, carrying more energy off as steam, which balances the extra energy supplied and keeps the temperature still at exactly 100 C. The rate at which heat escapes is very non-linear – extremely fast for temperatures above the threshold, extremely slow for temperatures below it. So long as the system is driven hard enough, it will get driven up against the non-linear limit and held there. The lapse rate does the same thing, except that instead of fixing the temperature, it fixes its gradient so you get a rigid slope that can freely float up and down in level.
The temperature at the average altitude of emission to space converges on the temperature that radiates the same energy the Earth absorbs. All levels above and below it are held in a fixed relationship to it by the lapse rate. The temperature at any other level is the temperature at the emission altitude plus the lapse rate times the difference in heights. Hence, the temperature at the surface differs by the lapse rate times the average height of emissions to space.
It’s interesting to consider what would happen if you had a strongly absorbing greenhouse material but a zero lapse rate. You’d get lots of backradiation, but no greenhouse warming. By marvelous happenstance we do have such a physical situation in the oceans. Water absorbs all thermal radiation within about 20 microns, making it something like 20,000 times more powerful a greenhouse material than the atmosphere. It’s a (relatively) easy calculation to show that if radiation was the only way heat could be transported, as the backradiation argument assumes, the temperature a metre down would be several thousand degrees! But water is almost incompressible, having a lapse rate of around 0.1 C/km, and so convection nullifies it entirely. Fortunate, eh? . . .
“The direction of net energy flow is determined only by the difference in temperatures, not the amount of stuff. If you have a big body at a cold temperature next to a small body at a very hot temperature, the cold body might be emitting more heat overall because of its bigger surface area, but the net flow is still from the hot body to the cold. Most of the heat emitted from the big cold body doesn’t hit the small body, because it’s so small. Only the temperature matters.
The way this is arranged varies depending on the configuration, but it always happens. People have had a lot of fun over the years trying to construct exotic arrangements of mirrors and radiators and insulators and heat engines to try to break the rule, but nobody has succeeded yet. The second law of thermodynamics is one on the most thoroughly challenged and tested of all the laws of physics. I do encourage people to try though. The prize on offer is a perpetual motion machine to the lucky winner who defeats it!
hat tip to Homer Simpson
Nullius in Verba holds forth here:
http://bishophill.squarespace.com/discussion/post/2471448?currentPage=5
David, I am not a fan of thought experiments about hypothetical worlds with or without CO2. I have read too many threads that go around in circles until everyone turns into wheels.
I do like what E.M. Smith (Chiefio) said sometime ago:
“It is peculiar that everyone is so taken in by the whole notion of the so-called ’radiative greenhouse effect’ being such an ingrained necessity, such a self-evident, requisite part, as it were, of our atmosphere’s inner workings. The ’truth’ and the ’reality’ of the effect is completely taken for granted, a priori. And yet, the actual effect is still only a theoretical construct.
In fact, when looking at the real Earth system, it’s quite evident that this effect is not what’s setting the surface temperature of our planet.
The whole thing can be stated in a simple, yet accurate manner.
The Earth, a rocky sphere at a distance from the Sun of ~149.6 million kilometers, where the Solar irradiance comes in at 1361.7 W/m2, with a mean global albedo, mostly from clouds, of 0.3 and with an atmosphere surrounding it containing a gaseous mass held in place by the planet’s gravity, producing a surface pressure of ~1013 mb, with an ocean of H2O covering 71% of its surface and with a rotation time around its own axis of ~24h, boasts an average global surface temperature of +15°C (288K).
Why this specific temperature? Because, with an atmosphere weighing down upon us with the particular pressure that ours exerts, this is the temperature level the surface has to reach and stay at for the global convectional engine to be able to pull enough heat away fast enough from it to be able to balance the particular averaged out energy input from the Sun that we experience.
It’s that simple.”
Update 1 May 5,2015
David, an additional point of some importance: There is empirical support for the lapse rate existing independent of IR activity.
Global warmists share an assumption that CO2 raises the effective radiating altitude, thereby warming the troposphere and the surface. Now this notion can be found in textbooks and indeed operates in all the climate models. Yet there is no empirical evidence supporting it. What data there is (radiosonde balloon readings) detects no effect from IR active gases upon the temperature profile in the atmosphere.
“It can be seen from the infra-red cooling model of Figure 19 that the greenhouse effect theory predicts a strong influence from the greenhouse gases on the barometric temperature profile. Moreover, the modeled net effect of the greenhouse gases on infra-red cooling varies substantially over the entire atmospheric profile.
However, when we analysed the barometric temperature profiles of the radiosondes in this paper, we were unable to detect any influence from greenhouse gases. Instead, the profiles were very well described by the thermodynamic properties of the main atmospheric gases, i.e., N 2 and O 2 , in a gravitational field.”
While water vapour is a greenhouse gas, the effects of water vapour on the temperature profile did not appear to be related to its radiative properties, but rather its different molecular structure and the latent heat released/gained by water in its gas/liquid/solid phase changes.
For this reason, our results suggest that the magnitude of the greenhouse effect is very small, perhaps negligible. At any rate, its magnitude appears to be too small to be detected from the archived radiosonde data.” Pg. 18 of referenced research paper
Open Peer Rev. J., 2014; 19 (Atm. Sci.), Ver. 0.1. http://oprj.net/articles/atmospheric-science/19 page 18 of 28
In summary David, it is observed and accepted by all that there is a ~33C difference between the temperature at the surface and at the effective radiating level (the tropopause, where convection stops). Warmists attribute that increase in temperature to the IR activity of CO2.
Others, including me, contend that it is the mass of the atmosphere, mostly O2 and N2 delaying the loss of heat from the surface until IR active gases are able to cool the planet effectively without obstruction. That retention of heat in the atmosphere is measurable in the lapse rate. And 90% of the IR activity is due to H2O, especially in the lower troposphere.
Science Matters 
Thank you for the reply. (My response is slow as I traveled to NAPA Ca. because my Mother In law was in the hospital due to congestive heart failure. Thankfully she recovered to the point that she is home now) I am really still learning about how the lapse rate works. It is intuitive that more mass (denser atmosphere) has a greater heat capacity. The relationship between heat capacity and “residence time” we have discussed.
It is intuitive to me that greater mass in the same area increases the residence time of energy encountering that mass when converted to kinetic energy. It is clear that translational motions are not necessarily accelerated but simply compressed. (More of the same mean motion in a smaller area.)
Outside of this I do not exactly understand the mechanism by which gases warm up when they’re compressed and cool down when allowed to expand, due to the changing atmospheric pressure. This is in part to my limited understanding of temperature. Commonly temperature is explained as the mean molecular motion of a group of molecules over a certain area, such as watts per sq. meter. Now I can visualize two mass units of different density, yet the individual molecules moving at the same rate. The one with more molecules would, IMV, have a higher T. greater density would produce more collisions against my skin, or against a thermometer, and would register as a higher T. Thus compressing gas would increase T due to more molecules in the same area. The opposite appears true as well.
I am not grasping another means of T change due to altitude. (Setting aside for the moment convection) Yet I see the changing sign of T change in the lapse rate diagram, where in some areas of the atmosphere the T increases at higher altitude. ( I will likely feel dumb when I understand this) Now I can grasp that at very high altitudes and very thin atmospheric pressure, the limited thin air would receive more insolation the higher up one goes, while at the same time the density change ratio would decrease due to very little density at such high elevations, but this does not intuitively compute to a reversed lapse rate.
I do understand some molecules have internal motions and thus energy absorbed can move into their vibrational degrees of freedom beyond translational. and not express as heat until that energy is conducted via collisional to other molecules. However I do not find a method of identifying an individual molecule, or even an individual photons energy as either heat, or heat potential. What is the temperature of an extremely energized photon or molecule? I will explain, as best as I can why this is important when I understand it.
Back to your point echoing EM Smith’s stance of not particularly liking some though experiments, such as my comments regarding a non GHG atmosphere. Like most things, I suppose it is in how one uses it. My attempt was to demonstrate non linearity in CS due to GHG within an atmosphere. By this I mean that it would appear unlikely that the logarithmic relationship between doubling CO2 would hold up at the extreme low end of that scale, as the percentage of conducted energy within an atmosphere increases the cooling or warming potential of GHG partially depends on weather it is radiating conducted energy, or LWIR from the surface. Thus the greater percentage of conducted energy within an atmosphere would increase the likelihood of the first batch of GHG molecules to be cooling rather then warming, or at a minimum increase the height at which GHG would be more likely to receive LWIR vs energy conducted energy from the surface.
This leads to a perhaps more important observation. W/V, a strong GHG, even in clear sky conditions significantly reduces surface insolation due to it ability to absorb disparate wave length insolation. Thus, in a non GHG atmosphere, a portion of the surface T would be elevated due to greater insolation reaching the surface then our current water vapor rich atmosphere allows. thus such a non GHG planet would partially make up for the lack of back radiation (The what, 33 degrees or so assigned to GHG) via greater surface insolation, and thus greater surface conduction to a non radiation atmosphere, then our current earth allows. Such a non GHG atmosphere would certainty hold more conducted energy (assuming our earth’s GHG molecules were replaced by an equal mass non GHG molecules) then our current GHG atmosphere, and certainly some of the GHG warming would be mitigated by greater surface insolation as well as increased residence time of conducted energy in a non radiating atmosphere.
Art any rate thanks in advance for taking the time to both listen, and to educate.
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David, thoughtful as always. I will think on a response, but for now, I suggest you read appendix A of a paper by Makarieva et al. It starts this way:
“The decrease of air temperature with height observed in the troposphere is conditioned by the presence of atmospheric greenhouse substances; however, it is not related to the magnitude of the planetary greenhouse effect.”
I take it from them that IR active gases are required to establish the gradient, but once in place, it is not sensitive to changes in composition of the atmosphere. This is similar to Nullius in Verba explanation.
Click to access 07e01s-hess_mg_.pdf
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Thanks Ron. The paper well describes and increases my understanding of the potential, and perhaps in some areas realized problems with deforestation. The appendix A regarding GHG affects on lapse rate covers numerous scenarios, and I will read several times before commenting.
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David, an additional point of some importance: There is empirical support for the lapse rate existing independent of IR activity.
Global warmists share an assumption that CO2 raises the effective radiating altitude, thereby warming the troposphere and the surface. Now this notion can be found in textbooks and indeed operates in all the climate models. Yet there is no empirical evidence supporting it. What data there is (radiosonde balloon readings) detects no effect from IR active gases upon the temperature profile in the atmosphere.
http://image.slidesharecdn.com/weatherballoon-110415115849-phpapp02/95/weather-balloon-pd-5-6-728.jpg?cb=1302869414
“It can be seen from the infra-red cooling model of Figure 19 that the greenhouse effect theory predicts a strong influence from the greenhouse gases on the barometric temperature profile. Moreover, the modeled net effect of the greenhouse gases on infra-red cooling varies substantially over the entire atmospheric profile.
However, when we analysed the barometric temperature profiles of the radiosondes in this paper, we were unable to detect any influence from greenhouse gases. Instead, the profiles were very well described by the thermodynamic properties of the main atmospheric gases, i.e., N 2 and O 2 , in a gravitational field.”
While water vapour is a greenhouse gas, the effects of water vapour on the temperature profile did not appear to be related to its radiative properties, but rather its different molecular structure and the latent heat released/gained by water in its gas/liquid/solid phase changes.
For this reason, our results suggest that the magnitude of the greenhouse effect is very small, perhaps negligible. At any rate, its magnitude appears to be too small to be detected from the archived radiosonde data.” Pg. 18 of referenced research paper
Open Peer Rev. J., 2014; 19 (Atm. Sci.), Ver. 0.1. http://oprj.net/articles/atmospheric-science/19 page 18 of 28
In summary David, it is observed and accepted by all that there is a ~33K difference between the temperature at the surface and at the effective radiating level (the tropopause, where convection stops). Warmists attribute that increase in temperature to the IR activity of CO2.
Others, including me, contend that it is the mass of the atmosphere, mostly O2 and N2 delaying the loss of heat from the surface until IR active gases are able to cool the planet effectively without obstruction. That retention of heat in the atmosphere is measurable in the lapse rate. And 90% of the IR activity is due to H2O, especially in the lower troposphere.
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Thanks Ron. I am still pondering… Can you articulate about the reversals in the lapse rate in the three upper levels of the atmosphere? Stratosphere = warmer with increase elevation / Menosphere = cooler with increased elevation / Thermosphere = warmer with increased elevation..
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Hi David, IIRC in the stratosphere it is the ozone absorbing UV from the sun. The full explanation is here:
http://okfirst.mesonet.org/train/meteorology/VertStructure.html
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