Guest post by Reed Coray
The following example illustrates the issues I have with reasoning often used to argue that increasing the amount of CO2 in the Earth’s atmosphere will increase both the Earth’s surface temperature and the Earth’s atmosphere temperature. Immediately following is a direct quote from URL
http://www.school-for-champions.com/science/heat_transfer_earth.htm
“The present situation is that there has been an increase in infrared-absorbing gases in the atmosphere, such as carbon dioxide (CO2) and methane (CH4). Energy that would normally escape into space is absorbed by these molecules, thus heating the atmosphere and spreading through convection currents. The average temperature of the atmosphere has increased 0.25 °C since 1980, mainly attributed to an increase in infrared-absorbing gases in the atmosphere.”
Although the above statement makes no direct reference to Earth surface temperature, I believe it carries the implication that greenhouse gases in the Earth’s atmosphere increase the Earth’s surface temperature.
I make two comments: the first is relevant only if the above implication is valid, the second is relevant independent of the validity of the implication. First, placing matter adjacent to a warm surface such that the matter is capable of absorbing/blocking radiation to space from the warm surface can lead to a decrease in the warm surface’s temperature. Second, increasing the amount of the absorbing/blocking matter can lower the temperature of the absorbing/blocking material.
Take for example an internal combustion engine whose metal surface is exposed to a vacuum. In addition to doing useful work, the engine produces thermal energy (heat). That thermal energy will produce a rise in the temperature of the engine’s surface such that in energy-rate equilibrium the rate energy is radiated to space from the engine’s surface is equal to the rate thermal energy is generated within the engine. By attaching radiating plates to the engine’s surface, some of the energy radiated to space from the engine’s original surface will be absorbed/blocked by the plates; but because thermal energy can be transferred from the engine to the plates via both radiation and conduction, the temperature of the engine’s original surface will be lowered. This is the principle of an air-cooled engine[1]: provide a means other than radiation of transferring heat from an engine to a large surface area from which heat can be removed via a combination of conduction, convection and radiation, and the engine’s surface temperature will be lowered.
If plates at a temperature lower than the original engine surface temperature are attached to the engine, it’s true that the temperature of the plates will increase to establish energy-rate equilibrium. Once energy-rate equilibrium is established, however, increasing the plate radiating area (adding additional matter that blocks more of the energy radiated from the original engine surface) will likely lower the plate temperature.
Thus, blocking the amount of surface radiation escaping to space does not necessarily increase the surface temperature; and increasing the amount of radiation blocking material does not necessarily increase the temperature of that material. In both cases (the Earth/Earth-atmosphere and the internal combustion engine in a vacuum), the heat eventually escapes to space–otherwise the temperature of the Earth’s surface and the engine would continue to rise indefinitely. The difference isn’t that the energy doesn’t eventually escape to space (it does in both cases), the difference is in the path the energy takes to reach space. The amount of generated thermal energy in conjunction with the path the thermal energy takes to get to space determines temperatures along the path; and adding more material may increase or decrease those temperatures. To say that “Energy that would normally escape into space is absorbed by these molecules, thus heating the atmosphere…” by itself is unwarranted; because an equivalent statement for the case of adding extra plate material to the engine would be “Energy that would normally escape to space from an engine with small attached plates is absorbed by additional plate material, thus heating the plates…” For air-cooled engines, this statement is not true—otherwise the plate surface area of air-cooled engines would be as small as possible.
It’s fairly easy to visualize why (a) adding thermally radiating plates to an air-cooled engine might decrease the engine’s surface temperature, and (b) increasing the area of the radiating plates might decrease the plate temperature. It’s not so easy to visualize, and may not be true, why (a) adding greenhouse gases to the Earth’s atmosphere decreases the Earth’s surface temperature; and (b) increasing the amount of atmospheric greenhouse gases lowers the temperature of the Earth’s atmosphere. I now present one possible argument. I do not claim that the argument is valid for greenhouse gases in the Earth’s atmosphere, but I do claim that the argument might be valid, and can only be refuted by an analysis more detailed than simply claiming “Energy that would normally escape into space is absorbed by these molecules, thus heating the atmosphere.”
If we assume that (a) matter cannot leave the Earth/Earth-atmosphere system, and (b) non-greenhouse gases radiate negligible energy to space, then for a non-greenhouse gas atmosphere the only way thermal energy can leave the Earth/Earth-atmosphere system to space is via radiation from the surface of the Earth. The rate radiation leaves the surface is in part a function of both the area and temperature of the surface. For a greenhouse gas atmosphere, energy can leave the Earth/Earth-atmosphere system to space both via radiation from the Earth’s surface and radiation from greenhouse gases in the atmosphere. Suppose it is true that the density of greenhouse gases near the Earth’s surface is such that radiation emitted from low-altitude greenhouse gases does not directly escape to space, but is in part directed towards the Earth’s surface and in part absorbed by other atmospheric greenhouse gases. As the atmospheric greenhouse gas density decreases with increasing altitude, radiation emitted from high-altitude greenhouse gases can directly escape to space.
Now it’s not impossible that since (a) in addition to radiation, heat is transferred from the Earth’s surface to greenhouse gases via conduction, and (b) convection currents (i) circulate the heated greenhouse gases to higher altitudes where energy transfer to space can take place and (ii) return cooler greenhouse gases to the Earth’s surface, that the process of heat transfer away from the Earth’s surface via greenhouse gases is more efficient than simple radiation from the Earth’s surface. Many engines are cooled using this concept. Specifically, a coolant is brought into contact with a heated surface which raises the coolant’s temperature via conduction and radiation, and the coolant is moved to a location where thermal energy transfer away from the coolant to a heat sink is more efficient than direct thermal energy transfer from the heated surface to the heat sink.
One way to realize increased thermal transfer efficiency would be to use a coolant, such as greenhouse gases, that efficiently radiates energy in the IR band (i.e., radiates energy at temperatures around 500 K). Another way would be to spread the heated coolant over a large surface area. Since surface area increases with increasing altitude, thereby providing expanded “area” (in the case of a gas, expanded volume) from which radiation to space can occur, it’s not clear to me (one way or the other) that greenhouse gases won’t act as a “coolant” reducing both the temperatures of the Earth’s atmosphere and the Earth surface.
[1] It’s true that for most air-cooled engines the main transfer of heat from the engine plates is via a combination of (a) conduction of heat to the air near the plates, and (b) convection that replaces the warm air near the plates with cooler air. To aid this process, a fan is often employed, or the engine is located on a moving vehicle and the vehicle’s motion through an atmosphere provides the flow of air across the plates. Although conduction/convection may be the primary means of heat dissipation from the plates, radiative cooling also dissipates heat.
Reed Coray:”If this interpretation is correct, then according to your equation as greenhouse gas levels increase, the temperature of the surface will increase to keep the equation in balance. So far so good. However, your equation implies that the rate energy is absorbed by greenhouse gases is never zero–in fact is a non-zero constant. So if your equation represents something physical, then isn’t it legitimate to ask: where does the energy that over time keeps being absorbed by (i.e., keeps accumulating) in the GHGs go? For energy rate equilibrium, if energy is absorbed by GHGs at a non-zero constant rate, doesn’t that energy have to leave the greenhouse gases at the same rate? If this is the case, shouldn’t your equation have in addition to a non-zero term for the “rate of energy aborption by GHGs” also have a non-zero term for the “rate of loss of energy by GHGs?””
First off, GH gases do not absorb energy in the terms you speak of it above, rather they make it so energy leaves the atmosphere more slowly than OTW. A consequence of this is that at any given time more energy will be in the system (and it will be warmer on average). All energy ultimately leaves the atmosphere *just the same as it always did* it just leaves more slowly on average. This relative slowness combined with the fact that gravity pulls heavy, warm air towards the surface (causing a lapse rate) accounts for the GH effect at the surface. Secondly, you math/logic is flawed above. Just because the difference btw the surface temperature and the GH effect is constant does not imply anything in particular about the GH effect. A change in the strength of GH (whether constant, linear, logarithmic or exponential) will cause a change in the surface temperature but nowhere does this require that change to be constant.
Cheers, 🙂
joeldshore says:
July 23, 2012 at 2:35 pm
“The idea is that an increase in greenhouse gases lowers the Earth’s emission back out into space by ~3.7 W/m^2 and the temperature at the effective radiating level has to rise by ~1 C to compensate. If this were to occur in such a way that the lapse rate remained constant (which it doesn’t), the temperature at the surface would rise by the same amount and that means that the surface itself would emit an additional ~5.5 W/m^2.”
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Many of you would probably consider what follows nit-picking, but I feel it’s worth pointing out, to avoid even more confusion as to how the radiative GHE is supposed to work. The temperature at the effective radiating level will NOT rise. The level itself will rise. The emission temperature must remain the same. That’s the whole point. If energy OUT is to balance energy IN (which is assumed to be constant) then the energy will have to be radiated off at the same effective temperature.
http://www.climatetheory.net/wp-content/uploads/2012/05/greenhouse-effect-held-soden-2000.png
From Soden & Held, 2000.
What happens with a doubling of atmospheric CO2 is that there’s a radiative imbalance imposed on the system – more IR is held back per unit of time (Earth’s rate of heat loss to space is reduced, amounting to the general 3.7 W/m^2 at TOA). This will force the radiating level to rise (by approx. 150 meters) for it to maintain its S-B radiating temperature. With a fixed lapse rate down to surface level, this would induce a ~1K rise in equilibrium temperature.
kristian;
Yeah, I get that. But the diagram is completely linear. Where is the justification for that. If water vapour was evenly distributed through the air column, then I could see that. But it isnt.
David Hoffer says:
Fair enough. We don’t need to talk about what the no-feedback value of the temperature change is at the surface. My point was simply that your claim that some new estimate of yours of this value lowered the estimate from the models of the sensitivity under doubling (you said from 2.6 to 1.8 C) is wrong. I am perfectly fine with leaving the estimate in the “no-feedback” case ambiguous since it depends on how the notion of “no feedbacks” is defined.
Yes…If you mean once all the adjustment has occurred, i.e. the Earth has come back into radiative balance. However, if you instantaneously double CO2 and then look, there were be only ~236 W/m^2 going out. Over time, that amount will rise as the climate system warms.
Yes…And, there is no assumption that it does change uniformly. However, you still seem to be stuck in a purely radiative view of things. In fact, in much of the troposphere, especially the tropics, the way the temperature rise tends to occur has more to do with maintaining the environmental lapse rate close to the appropriate (moist or dry) adiabatic lapse rate.
By they way, since we last talked about such things, Monckton made me aware of a paper that has helped me understand better why the estimates for the (conventionally-defined no-feedback) warming due to a doubling of CO2 tend to run a bit higher (by maybe 10% or so) than one gets from naively applying the Stefan-Boltzmann Equation using the effective emitting temperature, i.e., about 1.2 C rather than 1.05 C. And, the reason, as I now understand it, is exactly that the atmosphere will warm non-uniformly. If you consider the distribution of radiation from the different parts of the atmosphere that successfully escapes to space and it turns out that the colder parts warm more than the warmer parts, then this can actually result in a bit of a higher estimate of the warming that will occur relative to assuming that all of the emission comes from a level at a temperature of 255 K, which indeed is what the models predict.
Again, it is not worth spending a lot of time arguing about since it is essentially arbitrary, i.e., it depends on what you include as a feedback and what you include as a zeroth-order effect.
What is not arbitrary, however, is the total amount of warming that you get from a doubling, which is why I took issue with your argument that reduced that number by using inconsistent definitions of things.
Joeldshore write “The models and theories of radiative transfer in the atmosphere are backed up by a wealth of experiments. Basically, the entire field of remote sensing would cease to exist if it were wrong.”
Absolutely incorrect Joel. This statement implicitely starts of with the assumption that increasing the concentration of CO2 in the atmosphere has no other effects in the atmosphere that lead to a different result.
Science is fundamentally about observations and not modelling theories.
Kristian says:
Fair enough. What I should probably say is that the temperature at what was formerly the effective radiating level will rise. (Or, to put it another way, the rise in effective radiating level occurs immediately if you imagine an instantaneous increase in GHGs and then one finds oneself in a situation where this layer is now higher and colder and so the Earth is no longer emitting as much radiation as it is absorbing. Then, over time, the entire system warms [but certainly not uniformly] until the new effective radiating level is at 255 K and the radiative balance is re-established.)
By they way, since we last talked about such things, Monckton made me aware of a paper
>>>>>>>>>>>>>>
link?
If you consider the distribution of radiation from the different parts of the atmosphere that successfully escapes to space and it turns out that the colder parts warm more than the warmer parts
>>>>>>>>>>>>>>>>
But do they? We need to look at it from both an altitude and latitude perspective, plus probably a seasonal one. In high altitude winter temps, there is far less water vapour, so the effects of CO2 become more pronounced at lower altitudes, one reason we would expect to see polar amplification. Or should we?
At -40C, earth surface is radiating 167 w/m2. At +40 C it is radiating 548 w/m2. So, we’d expect to see CO2 effects being more pronounced in lower water vapour concentrations, but if there’s 1/3 the w/m2 to absorb and re-radiate in the first place, we get a completely different effect. Run that same thought from an altitude basis with water vapour declining with temperature…. so, do the cold parts warm more than the warm parts? My guess is still yes, but the warming would be a lot more uniform than one might otherwise expect. My point being that even from a strictly radiative physics perspective, one would not expect a linear relationship across altitudes, latitudes, and seasons.
In fact, if you refer to ERBE, you’ll find that the poles have a net loss of energy to space, and the tropics a net gain. The tropics move their excess heat to the poles via convection, water currents, etc. So, how much of the 500 w/m2 that CO2 is in a position to intercept goes into warming the surface and how much results in increased convection moving energy to the poles? Now we measure polar amplication and attribute it to what? CO2 effects directly? Or increased energy being moved from tropics to poles? Or some combination?
To be honest, I don’t have a clue. But that’s only scratching the surface of the complexity involved, and I just don’t see the response being linear. Its going to be less at the warmest places and most in the coldest places, hence the surface response will be less than the “average” response by some amount. My amount is a rough guestimate I will admit. But linear just doesn’t cut it.
That said, I’m still looking for an answer to my original question. If it makes no difference, then why did AR3 specify that they meant as measured at the effective black body temperature of earth? Further, AR4 goes on to specifically say that the temperature change may be muted at surface and may not follow the effective black body temp change (yes, they actually said that, part of why I started thinking about how they defined it in the first place, and sorry don’t have a link for that, but itz in there)
RE: davidmhoffer: (July 23, 2012 at 4:51 pm)
“To be precise, take the post albedo number and multiply by 0.5 for curvature of the earth and then multiply by 0.5 yet again to accomodate day-night.”
The nominal cross-sectional area of the Earth for intercepting solar radiation is approximately pi times the radius squared. There may be some fuzziness about this radius because of the atmosphere and increasing reflectivity at the fringes, and also the slight remaining curvature of solar radiation striking the earth. All that energy being intercepted must be radiated back out from the Earth’s surface having an area of four pi times the square of another fuzzy radius of the Earth. If we ignore the fuzziness, we get an *average* required surface referenced ‘terrestrial’ constant of 25 percent of the albedo reduced solar constant. (multiplied by one minus the albedo factor.) The net result is the same as you say above.
Side Note: Because energy radiated is proportional to the fourth power of the absolute temperature, the average radiated energy equivalent temperatures, often cited, are equivalent to the fourth root of the average of absolute temperatures raised to the fourth power.
Konrad “I have a very simple multiple choice question for those still commenting on this thread.
I have two 1m spheres of thin LDPE plastic (transparent to LWIR) in a sunless vacuum in deep space. Both spheres contain gas at an initial temperature of 100C. Sphere 1 contains 100% O2. Sphere 2 contains 99% O2 and 1% CO2. Which sphere cools faster? Is the answer :
A. Sphere 1 cools faster.
B. Sphere 2 cools faster.
C. Sphere 1 and 2 cool at the same rate.
Or
D. The spherical chicken found in the same region of space has “Property of Pierrehumbert” tattooed on its butt.”
Common sense says “C” but from by “argument from authority” , CO2 cools 100’s or thousands times faster than O2 so “B” . Konrad , rest assured, you can safely put your hand right up next to sphere1 and you won’t get burnt because O2 doesn’t radiate much.
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-8.html
From AR4 WG1 2.8.1
It should be noted that a perturbation to the surface energy budget involves sensible and latent heat fluxes besides solar and longwave irradiance; therefore, it can quantitatively be very different from the RF, which is calculated at the tropopause, and thus is not representative of the energy balance perturbation to the surface-troposphere (climate) system. ”
RF here stands for radiative forcing. Note that it actually calls out that the surface energy budget is likely to be quantitatively different from the RF change. What they DON’T say is if it will be higher or lower. I spent a lot of hours trying to get that answer, and all that is in there is vague statements upon vague statements. There’s a couple of other sections where they tackle this in other ways and it becomes clear that they think the value will be lower at surface, or at least that is my read. One of my big issues with AR4 is that they are in fact so freaking vague on things like this, and the way the numbers are represented is always in worst possible context.
You can also refer to section 2.2
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-2.html
check out figure 2.2 where they discuss different ways to model the effects of RF change, with temp changes much lower at surface than at higher altitudes. It has been a long time since I read through this, but I went through this section in some detail and it was clear to me that AR4 was written to mean that surface temps would change LESS than the value they were calculating for equilibrium response. How much less? I dunno, but the fact is they represent the change as being +1 degree, then quietly bury in the detailed analysis that the surface temperature change will be less than that.
joeldshore says:
July 23, 2012 at 7:32 pm
“What I should probably say is that the temperature at what was formerly the effective radiating level will rise. (Or, to put it another way, the rise in effective radiating level occurs immediately if you imagine an instantaneous increase in GHGs and then one finds oneself in a situation where this layer is now higher and colder and so the Earth is no longer emitting as much radiation as it is absorbing. Then, over time, the entire system warms [but certainly not uniformly] until the new effective radiating level is at 255 K and the radiative balance is re-established.)”
Only nitpickers will argue with that. That is the basic story. We should move on now.
In reply to joeldshore says: July 23, 2012 at 7:32 pm “What I should probably say is that the temperature at what was formerly the effective radiating level will rise…” But the satellite data for the Pacific in Griggs and Harries (JoC 2007) show NO rise in temperature at ANY altitude between 1970 and 2003. How do you explain that? When you say “Or, to put it another way, the rise in effective radiating level occurs immediately if you imagine an instantaneous increase in GHGs and then one finds oneself in a situation where this layer is now higher and colder and so the Earth is no longer emitting as much radiation as it is absorbing” does not help as the data on OLR I previously linked to from NOAA-NCEP reanalysis also belie this claim, as OLR INCREASED by 6 W/sq.m. between 1970 and 2003 despite the increase in CO2 of over 50 ppmv.
ahem… was I just noticed that figure 2.2 actually shows the opposite of what I said, my mistake. I was skimming and linked to it thinking it was something else. There’s a whole pile of junk in this section that is contradictory, and I don’t have time to go through it in detail again to find the specific sections I was thinking of. Really not worth it anyway since AR5 is on the horizon.
davidmhoffer says:
July 23, 2012 at 8:16 pm
ahem… was I just noticed that figure 2.2 actually shows the opposite of what I said, my mistake. I was skimming and linked to it thinking it was something else. There’s a whole pile of junk in this section that is contradictory, and I don’t have time to go through it in detail again to find the specific sections I was thinking of. Really not worth it anyway since AR5 is on the horizon.
Surely you do not mean to imply that for all of the billions spent since AR1, all the IPCC has created with its thousands of climate scientists is …. worthless illiterate papers that cannot be understood by nor explained by even the supporters of the 1.5 trillion dollar-per-year UN effort to kill millions and harm billions of innocents?
RACookPE1978 says:
July 23, 2012 at 8:46 pm
>>>>>>>>>>>>>>>
I respond with the following quote which I trust summarizes the matter nicely:
“One must say clearly that we redistribute de facto the world’s wealth by climate policy. One has to free oneself from the illusion that international climate policy is environmental policy. This has almost nothing to do with environmental policy anymore.”
~ Ottmar Edenhofer, Co-Chair, UN/IPCC WG-3
paulinuk says:
July 23, 2012 at 8:06 pm
Konrad “I have a very simple multiple choice question for those still commenting on this thread.
I have two 1m spheres of thin LDPE plastic (transparent to LWIR) in a sunless vacuum in deep space. Both spheres contain gas at an initial temperature of 100C. Sphere 1 contains 100% O2. Sphere 2 contains 99% O2 and 1% CO2. Which sphere cools faster? Is the answer :
A. Sphere 1 cools faster.
B. Sphere 2 cools faster.
C. Sphere 1 and 2 cool at the same rate.
Or
D. The spherical chicken found in the same region of space has “Property of Pierrehumbert” tattooed on its butt.”
Common sense says “C” but from by “argument from authority” , CO2 cools 100’s or thousands times faster than O2 so “B” . Konrad , rest assured, you can safely put your hand right up next to sphere1 and you won’t get burnt because O2 doesn’t radiate much.
Well, first of all the LDPE doesn’t radiation much in the IR, because it doesn;t absorb there (not quite 100% true, but let us assume that. Since the sphere’s are in a vacuum, the only way to lose energy is by radiation (hey, it’s your problem, don’t complain). Sphere 2 can radiate faster, it cools faster. and btw, Eli was under the impression that you ain;t supposed to do the D thing here.
Glad to be of service otherwise.
Most of your explanation involves the conductance of energy away from the molecule, not the radiation of energy away from the molecule. If you were to take a single CO2 molecule in isolation and subject it to a stream of photons of the correct frequency for it to absorb, what happens? Does the vibrational energy of the molecule continue to increase, does the radiative energy convert into another form of energy, does the rate of photons emitting increase, or does something else happen?
One of the things you have to know to think about this question is that there are slight anharmonicities in vibrational quantum states and that transitions are only allowed that change the rotational quantum numbers by 1 or zero, so pumping in a single frequency doesn’t do much once absorption and stimulated emission balance. Get a nasty enough light source and you can do interesting stuff (look up, for example IR multiphoton dissociation, a ton of papers in the late seventies and early eighties).
Shawnhet says: July 23, 2012 at 5:26 pm
I must not be communicating well. I agree that the presence of greenhouse gases (or for that matter any material) in the Earth’s atmosphere will likely alter, both in a transient sense and in a steady-state sense, the temperature profile (i.e., the temperature as a function of position) of the Earth’s surface and atmosphere. I make no quantitative statements regarding how greenhouse gases affect the temperature profile.
What I object to are (a) the statement that “greenhouse gases slow down the rate of cooling” and (b) the argument that the statement justifies the claim that “greenhouse gases” in the Earth’s atmosphere warm the Earth’s surface and its atmosphere.”
Before going further, from something you wrote it occured to me that as applied to the Earth/Earth-atmosphere system in energy-rate-equilibrium, we might be interpreting the phrase “slow down the rate of cooling” in different ways. You wrote: First off, GH gases do not absorb energy in the terms you speak of it above, rather they make it so energy leaves the atmosphere more slowly than OTW. From this I infer that you might interpret the phrase “slow down the rate of cooling” to mean: “if X is the TIME it takes an identifiable unit of heat (whatever that is) to travel from the Earth’s surface to space in the absence of greenhouse gases in the Earth’s atmosphere, and Y is the TIME it takes a comparable identifiable unit of heat to travel from the Earth’s surface to space in the presence of greenhouse gases in the Earth’s atmosphere, then the phrase “slow down the rate of cooling” means that X and Y are both positive and that Y is greater than X.
As applied to the Earth/Earth-atmosphere system in energy-rate-equilibrium, the way I interpret the phrase is that if X is the RATE energy leaves the Earth/Earth-atmosphere system in the absence of greenhouse gases in the Earth’s atmosphere, and Y is the RATE energy leaves the Earth/Earth-atmosphere system in the presence of greenhouse gases in the Earth’s atmosphere, then the phrase “slow down the rate of cooling” means that X and Y are positive and that Y is less than X.
If neither of the above reflects what you mean by the phrase “energy leaves the atmosphere more slowly than OTW”, please clarify.
Using my definition of the phrase, if after adding greenhouse gases to the Earth’s atmosphere and waiting until all transients have died out, the rate energy ENTERS the Earth/Earth atmosphere system is unchanged, then the addition of greenhouse gases to the Earth’s atmosphere will, after all transients have died out, leave the rate energy LEAVES the Earth/Earth atmosphere system unchanged. Otherwise, the Earth/Earth atmosphere system will either accumulate thermal energy without bound or lose thermal energy until there is none left.
Thus I believe that after all transients have died out, the rate of cooling won’t have changed; and if the rate of cooling hasn’t changed, how can it be said either that (a) the rate of cooling has slowed down or (b) it is this slow down that causes the Earth’s surface temperature to increase? Again, I’m not saying that greenhouse gases in the Earth’s atmosphere won’t alter the Earth’s temperature profile. What I am saying is the argument that “a cooling rate slow down” exists and “the cooling rate slow down” CAUSES the temperature profile to change cannot be justified.
I’ll give my point of view one more try. I ask a series of questions. All questions apply to steady-state conditions–i.e., after the transients introduced by any changes in atmospheric greenhouse gases have died out–and to the situation that all energy sources other than energy coming from the sun are negligible.
First Question: Does the addition of greenhouse gases to the Earth’s atmosphere alter the RATE the Earth/Earth-atmosphere system absorbs solar energy? Yes or No.
If “Yes”, please explain your answer and stop–there’s no sense going forward with the questions. If “No” continue.
Second Question: Is the RATE energy enters the Earth/Earth-atmosphere system the same as the RATE energy leaves the Earth/Earth-atmosphere system? Yes or No.
If “No”, please explain your answer and stop–there’s no sense going forward with the questions. If “Yes” continue.
Third Question: If we get to this question, we are in agreement (but we may both be wrong) that (a) the RATE energy enters the Earth/Earth-atmosphere system is unaffected by the presence of greenhouse gases in the Earth’s atmosphere and (b) the RATE energy leaves the Earth/Earth-atmosphere system equals the RATE energy enters the Earth/Earth-atmosphere system. Can we then conclude that the RATE energy leaves the Earth/Earth-atmosphere system is unaffected by the presence of greenhouse gases in the Earth’s atmosphere?
If “No”, please explain your answer and stop–there’s no sense going forward with the questions. If “Yes” continue.
Fourth Question: If we get to this question, we are in agreement that the rate energy leaves the Earth/Earth-atmosphere system is unaffected by the presence of greenhouse gases in the atmosphere. Is the RATE energy leaves the Earth/Earth-atmosphere system the same thing as the RATE OF COOLING OF THE EARTH/EARTH-ATMOSPHERE SYSTEM?
If “No”, please explain your answer and stop–there’s no sense going forward with the questions. If “Yes” continue.
Fifth Question: If we’ve reached this question, we are in agreement that the “rate of cooling of the Earth/Earth-atmosphere system” is unaffected by the presence of greenhouse gases. Is it then logical to argue that the presence of greenhouse gases in the Earth’s atmosphere “slow down the rate of cooling” and it is the “slow down of the rate cooling” that causes the Earth/Earth-system temperature to be different in the presence/absence of atmospheric greenhouse gases?
If “No”, stop–we are in agreement. If “Yes”, feel free to add a comment; but then we’ve probably reached a point where further discussion is useless.
Cheers
Well I’m sure glad I didn’t waste my time on this thread.
Luckily I was short circuited at a very early stage by the suggestion that black body emission was equal to: k T^4
(k) is Boltzmann’s constant; (sigma) is the Stefan-Boltzmann constant used in total integrated black body emission; so I exited stage left immediately on reading that, along with the earth cooling by losing heat to space. The earth neither receives from, nor loses to “space”, ANY HEAT. well not any measurable amount.
And it’s nice to read a citation to a source that agrees with me, that all matter above zero Kelvins, including neutral gases emits thermal radiation. And the spectrum of thermal radiation for any material Temperature, has no lower bound, and no upper bound of frequency or wavelength, although 98% of the energy is contained in a 16 to one wavelength (or frequency) range.
No we don’t call it black body radiation, because there simply aren’t big enough masses of neutral gases around near us, to completely absorb ALL electromagnetic radiation that impinges on them.
But there are large amounts of gases containing vast numbers of molecules in collision, thereby exhibiting a measurable Temperature, and therefore able to radiate and absorb EM radiation of ANY frequency or wavelength, including the the range from 0.7 microns to 100 microns, commonly referred to as Infra-red.
That entire contraption known as the large Hadron collider, is so ruddy big, as is the Stanford Linear Accelerator (SLAC) because particle Physicists, along with Radio Astronomers; and other Radio Physicists (such as me), are mindful of the fact that accelerated electric charges; aka variable electric currents travelling any non zero distance must radiate EM waves as shown eons ago, by the likes of Heinrich Hertz, and James Clark Maxwell.
Nils Bohr aided by Arnold Sommerfeld, tried to veto that requirement, in their quite arbitrary (but ingenious) Bohr/Sommerfeld atom model; until quantum mechanics came along and bailed them out of their predicament, so sanity remains, and accelerated charges, including atoms in collision still radiate EM waves.
I’m sorry for those hardy souls who kept feeding those pesky trolls, on this thread; I’m outta here.
That last thing you said, Reed. Go with that. This thread has been over for some time.
What an intense thread. I read Reed’s piece 3 times and 90% of all the posts here and I think I get the gist. I see we have a physicist or two and I have read Dr. Brown’s posts here as well.
I will get to the discussion of the radiative transfer but here is some necessary background discussion:
First of all Reed well done: well written, explained and defended. I read all of your response comments. Even if some of your claims/possible occurrences do not hold to be true, the central themes will hold up, I am certain.
To begin with, Anthony Watts, among others have already conclusively shown that the weather stations have shown a heating bias via UHI, and Steve McIntyre and the paper from have shown warming biases due to improper homogenization procedures not well verified/validated within the statistical or scientific community at large. There is Koutsoyannis as well. Thus, before I mention anything about physics of greenhouse gases, whether it acts as a blanket, warms/cools/does nothing, we already have enough data and statistical analysis to obliterate, if not all so called recorded global warming, on the instrumental record, then >95% of it. Statistically W.M. Briggs who is less harsh about Mann et al., and GHG forcings also destroys the idea of using homogenization of weather stations, the statistics used in the constructions of the hockey stick using smoothing methods is shoddy, even if not performed on purpose.
Okay now on to the physics, thermodynamics fun stuff:
First in simple words greenhouse gases CANNOT induce increased work on the system, so that the colder air/atmosphere/greenhouse gas transmits heat to a warmer object. Air conditioners and refrigerators do this but not without exerting work through the compressor. Adiabatic temperature changes do occur in nature via work being exerted by external forces like atmospheric pressure, and here is where the basic underpinnings of the lapse rate discussion. However, keep in mind GHG’s do not add any energy or WORK to the system in any way. In addition GHG’s act more as thermal buffers heating and cooling the planet, rather than just “slowing the cooling process” “trapping heat/heated air/gases” etc…
Thus borrowing from my own comments and direct quotes elsewhere:
“The real question is: is the science sound based upon the immutable laws of heat transfer and the answer is a resounding no:
“Clausius Statement of the Second Law
Clausius Statement of the Second Law
The Clausius statement of the second law states
It is impossible for any system to operate in such a way that the sole result would be an energy transfer by heat from a cooler to a hotter body.
Heat can transfer from a cooler body to a hotter body if other effects accomplishing the heat transfer occur within the system or its surroundings, or both. Air conditioners and refrigerators are devices to transfer heat from a cool space to its hot surroundings. But both of them need power input. The Clausius statement says that an air conditioner cannot cool a room without power input.” Taken from: http://www.ecourses.ou.edu/cgi-bin/ebook.cgi?doc=&topic=th&chap_sec=05.2&page=theory.
Then there is excellent research on negative feedbacks as Reed alludes to:
http://wattsupwiththat.com/2011/09/20/new-peer-reviewed-paper-clouds-have-large-negative-feedback-cooling-effect-on-earths-radiation-budget/
And preliminary findings:
http://wattsupwiththat.com/2012/07/18/new-paper-on-global-water-vapor-puts-climate-modelers-in-a-bind/
Of course cloud cover with water vapor holds in heated air, or as we know heated gases, but adding more C02 and CH4 does not automatically mean we are going to get a hotter planet. As all of the IPCC reports show and as do the numerous cloud physics/atmospheric studies too, we poorly understand cloud cover, micro-physics and dynamic formation. Sure clouds at night block the leaving of some radiation/heat flow and during the day albedo reflects back radiation, but the system is so complex that the margin of error and depth of uncertainties are still far too large. Add (again, to make it clear, regardless of what letters you have after your name) to that the second law prohibits movement of heat transfer from a colder object to hotter, and , the saturation bands of C02/logarithmic activity and we see why the level of certainty and statistical clustering of 3 degrees for a doubling of C02 just cannot be, and this applies exactly because the planet obeys laws of non-equilibrium thermodynamics in an open or if you prefer semi-open system.” Yes, that is right we are not dealing with equilibrium thermodynamics but non-equilibrium, however, some researchers have been trying over the past couple of years to reconcile that fact and produce complex models utilizing non-equilibrium thermodynamics to push the agenda of C02 = linear relationship to global warming, and usually the agenda is one of CAGW. If this thread stays alive and their are responses to this post then we can get more technical/mathematical.
The planet is not a closed or semi closed system and the behavior of clouds and their micro-physics leave many known unknowns and unknown unknowns… Next time I should say what is wrong with the so called climate sensitivity as well.
References
http://wmbriggs.com/blog/?p=1459
http://climateaudit.org/?s=homogenization
http://www.ecourses.ou.edu/cgi-bin/ebook.cgi?doc=&topic=th&chap_sec=05.2&page=theory
Concepts in Thermal Physics Chapter 13, 2006. Blundell, Stephen J. Blundell, Katherine M.
Peter Atkins Physical Chemistry: All over the textbook.
http://greenhouse.geologist-1011.net/
http://www4.uwsp.edu/geo/faculty/ritter/geog101/textbook/atmospheric_moisture/lapse_rates_1.html
Reed,
I’ll try to answer your questions, please bear in mind though that I don’t think that we necessarily mean the same things with some of our terminology.
“First Question: Does the addition of greenhouse gases to the Earth’s atmosphere alter the RATE the Earth/Earth-atmosphere system absorbs solar energy? Yes or No.”
I would rephrase this as saying that GH gases do not block the radiation arriving from the sun allowing it to hit the Earth and warm it.
“Second Question: Is the RATE energy enters the Earth/Earth-atmosphere system the same as the RATE energy leaves the Earth/Earth-atmosphere system? Yes or No.”
It depends on when you measure this precisely. Consider a tap attached to a garden hose. Before you attach the hose the water hits the ground at the same rate that it leaves the tap. Then you attach the hose and the water leaves the tap at a greater rate than it hits the ground (until the hose is full of water). Then, once the hose is full of water, the water hits the ground at exactly the same rate as it leaves the tap.
If one imagines that there is a property is dependent on the amount of water that has left the tap but has yet to hit the ground then we could legitimately claim that the length of hose btw the tap and the ground caused more of this property without altering the *long-term* equivalency btw water-in and water-out or magically creating water or whatever.
The rest of your questions rest on this fundamental misunderstanding in terms of the rate of cooling of the Earth. It would not make sense to argue that because the water out of the hose is exactly equal to the the water hitting the ground in the steady state that it is impossible for a hose to allow (magically) the water from the tap to move 20 feet out from the tap before hitting the ground. Likewise, the fact that at equilibrium, energy in = energy out regardless of the presence of GH gases does not mean that GH gases cannot raise the Earth’s temperature.
I hope the above can help you frame your questions a bit better.
Cheers, 🙂
Communicating any kind of science to non-scientists requires simplification. Attacking the simplified explanations of science because you don’t like the solutions that you imagine they are supposed to be provoking people into demanding is pretty weird. If you want to prove the science wrong, you need to understand the science itself.
Eli Rabett says:
July 23, 2012 at 9:21 pm
One of the things you have to know to think about this question is that there are slight anharmonicities in vibrational quantum states and that transitions are only allowed that change the rotational quantum numbers by 1 or zero, so pumping in a single frequency doesn’t do much once absorption and stimulated emission balance. Get a nasty enough light source and you can do interesting stuff (look up, for example IR multiphoton dissociation, a ton of papers in the late seventies and early eighties).
>>>>>>
Thanks Eli, I think that I found most of my answers under Wikipedia’s description for ‘Spontaneous Emission’. Your direction to IR multiphoton dissociation is interesting because it confirms a thought that I had that if you exceed the absorption and stimulated emission balance you can break the molecular bonds – unless I miss the mark, this can occur naturally but the chances of it happening are about the same as the odds of me winning the next lottery without buying a ticket 😉
paulinuk says:
July 23, 2012 at 8:06 pm
Eli Rabett says:
July 23, 2012 at 9:10 pm
———————————–
You are both correct. The answer is of course B. The gas sphere with 99% O2 and 1% CO2 cools quicker. The question was asked to illustrate the point that was raised by Reed Corays post. The cooling effect of added CO2 in our atmosphere appears neglected in CAGW discussions.
The warming effect of increasing CO2 is an inverse logarithmic function of its concentration in the atmosphere.
The cooling effect of increasing CO2 is a linear function of its concentration in the atmosphere.
At some point the warming logarithmic curve must cross the linear slope of cooling. This could be called the “Point of no concern”
Hopefully this graph illustrates the issue. http://i48.tinypic.com/2pp0hed.jpg
Tim Folkerts writes “Your model seems to be that “average radiating height” is a fundamental feature of the earth, independent of where the molecules emitting the IR radiation are found”
I dont have a model Tim. I simply look at what we know and what we dont know and see the disconnects and there is a massive disconnect between more CO2 = higher average radiating altitude because it implicitely begins with “all else being equal” which is a nonsense.