By Robert G. Brown, Duke University (elevated from a WUWT comment)
I spent what little of last night that I semi-slept in a learning-dream state chewing over Caballero’s book and radiative transfer, and came to two insights. First, the baseline black-body model (that leads to T_b = 255K) is physically terrible, as a baseline. It treats the planet in question as a nonrotating superconductor of heat with no heat capacity. The reason it is terrible is that it is absolutely incorrect to ascribe 33K as even an estimate for the “greenhouse warming” relative to this baseline, as it is a completely nonphysical baseline; the 33K relative to it is both meaningless and mixes both heating and cooling effects that have absolutely nothing to do with the greenhouse effect. More on that later.
I also understand the greenhouse effect itself much better. I may write this up in my own words, since I don’t like some of Caballero’s notation and think that the presentation can be simplified and made more illustrative. I’m also thinking of using it to make a “build-a-model” kit, sort of like the “build-a-bear” stores in the malls.
Start with a nonrotating superconducting sphere, zero albedo, unit emissivity, perfect blackbody radiation from each point on the sphere. What’s the mean temperature?
Now make the non-rotating sphere perfectly non-conducting, so that every part of the surface has to be in radiative balance. What’s the average temperature now? This is a better model for the moon than the former, surely, although still not good enough. Let’s improve it.
Now make the surface have some thermalized heat capacity — make it heat superconducting, but only in the vertical direction and presume a mass shell of some thickness that has some reasonable specific heat. This changes nothing from the previous result, until we make the sphere rotate. Oooo, yet another average (surface) temperature, this time the spherical average of a distribution that depends on latitude, with the highest temperatures dayside near the equator sometime after “noon” (lagged because now it takes time to raise the temperature of each block as the insolation exceeds blackbody loss, and time for it to cool as the blackbody loss exceeds radiation, and the surface is never at a constant temperature anywhere but at the poles (no axial tilt, of course). This is probably a very decent model for the moon, once one adds back in an albedo (effectively scaling down the fraction of the incoming power that has to be thermally balanced).
One can for each of these changes actually compute the exact parametric temperature distribution as a function of spherical angle and radius, and (by integrating) compute the change in e.g. the average temperature from the superconducting perfect black body assumption. Going from superconducting planet to local detailed balance but otherwise perfectly insulating planet (nonrotating) simply drops the nightside temperature for exactly 1/2 the sphere to your choice of 3K or (easier to idealize) 0K after a very long time. This is bounded from below, independent of solar irradiance or albedo (or for that matter, emissivity). The dayside temperature, on the other hand, has a polar distribution with a pole facing the sun, and varies nonlinearly with irradiance, albedo, and (if you choose to vary it) emissivity.
That pesky T^4 makes everything complicated! I hesitate to even try to assign the sign of the change in average temperature going from the first model to the second! Every time I think that I have a good heuristic argument for saying that it should be lower, a little voice tells me — T^4 — better do the damn integral because the temperature at the separator has to go smoothly to zero from the dayside and there’s a lot of low-irradiance (and hence low temperature) area out there where the sun is at five o’clock, even for zero albedo and unit emissivity! The only easy part is to obtain the spherical average we can just take the dayside average and divide by two…
I’m not even happy with the sign for the rotating sphere, as this depends on the interplay between the time required to heat the thermal ballast given the difference between insolation and outgoing radiation and the rate of rotation. Rotate at infinite speed and you are back at the superconducting sphere. Rotate at zero speed and you’re at the static nonconducting sphere. Rotate in between and — damn — now by varying only the magnitude of the thermal ballast (which determines the thermalization time) you can arrange for even a rapidly rotating sphere to behave like the static nonconducting sphere and a slowly rotating sphere to behave like a superconducting sphere (zero heat capacity and very large heat capacity, respectively). Worse, you’ve changed the geometry of the axial poles (presumed to lie untilted w.r.t. the ecliptic still). Where before the entire day-night terminator was smoothly approaching T = 0 from the day side, now this is true only at the poles! The integral of the polar area (for a given polar angle d\theta) is much smaller than the integral of the equatorial angle, and on top of that one now has a smeared out set of steady state temperatures that are all functions of azimuthal angle \phi and polar angle \theta, one that changes nonlinearly as you crank any of: Insolation, albedo, emissivity, \omega (angular velocity of rotation) and heat capacity of the surface.
And we haven’t even got an atmosphere yet. Or water. But at least up to this point, one can solve for the temperature distribution T(\theta,\phi,\alpha,S,\epsilon,c) exactly, I think.
Furthermore, one can actually model something like water pretty well in this way. In fact, if we imagine covering the planet not with air but with a layer of water with a blackbody on the bottom and a thin layer of perfectly transparent saran wrap on top to prevent pesky old evaporation, the water becomes a contribution to the thermal ballast. It takes a lot longer to raise or lower the temperature of a layer of water a meter deep (given an imbalance between incoming radiation) than it does to raise or lower the temperature of maybe the top centimeter or two of rock or dirt or sand. A lot longer.
Once one has a good feel for this, one could decorate the model with oceans and land bodies (but still prohibit lateral energy transfer and assume immediate vertical equilibration). One could let the water have the right albedo and freeze when it hits the right temperature. Then things get tough.
You have to add an atmosphere. Damn. You also have to let the ocean itself convect, and have density, and variable depth. And all of this on a rotating sphere where things (air masses) moving up deflect antispinward (relative to the surface), things moving down deflect spinward, things moving north deflect spinward (they’re going to fast) in the northern hemisphere, things moving south deflect antispinward, as a function of angle and speed and rotational velocity. Friggin’ coriolis force, deflects naval artillery and so on. And now we’re going to differentially heat the damn thing so that turbulence occurs everywhere on all available length scales, where we don’t even have some simple symmetry to the differential heating any more because we might as well have let a five year old throw paint at the sphere to mark out where the land masses are versus the oceans, and or better yet given him some Tonka trucks and let him play in the spherical sandbox until he had a nice irregular surface and then filled the surface with water until it was 70% submerged or something.
Ow, my aching head. And note well — we still haven’t turned on a Greenhouse Effect! And I now have nothing like a heuristic for radiant emission cooling even in the ideal case, because it is quite literally distilled, fractionated by temperature and height even without CO_2 per se present at all. Clouds. Air with a nontrivial short wavelength scattering cross-section. Energy transfer galore.
And then, before we mess with CO_2, we have to take quantum mechanics and the incident spectrum into account, and start to look at the hitherto ignored details of the ground, air, and water. The air needs a lapse rate, which will vary with humidity and albedo and ground temperature and… The molecules in the air recoil when the scatter incoming photons, and if a collision with another air molecule occurs in the right time interval they will mutually absorb some or all of the energy instead of elastically scattering it, heating the air. It can also absorb one wavelength and emit a cascade of photons at a different wavelength (depending on its spectrum).
Finally, one has to add in the GHGs, notably CO_2 (water is already there). They have the effect increasing the outgoing radiance from the (higher temperature) surface in some bands, and transferring some of it to CO_2 where it is trapped until it diffuses to the top of the CO_2 column, where it is emitted at a cooler temperature. The total power going out is thus split up, with that pesky blackbody spectrum modulated so that different frequencies have different effective temperatures, in a way that is locally modulated by — nearly everything. The lapse rate. Moisture content. Clouds. Bulk transport of heat up or down via convection. Bulk transport of heat up or down via caged radiation in parts of the spectrum. And don’t forget sideways! Everything is now circulating, wind and surface evaporation are coupled, the equilibration time for the ocean has stretched from “commensurate with the rotational period” for shallow seas to a thousand years or more so that the ocean is never at equilibrium, it is always tugging surface temperatures one way or the other with substantial thermal ballast, heat deposited not today but over the last week, month, year, decade, century, millennium.
Yessir, a damn hard problem. Anybody who calls this settled science is out of their ever-loving mind. Note well that I still haven’t included solar magnetism or any serious modulation of solar irradiance, or even the axial tilt of the earth, which once again completely changes everything, because now the timescales at the poles become annual, and the north pole and south pole are not at all alike! Consider the enormous difference in their thermal ballast and oceanic heat transport and atmospheric heat transport!
A hard problem. But perhaps I’ll try to tackle it, if I have time, at least through the first few steps outlined above. At the very least I’d like to have a better idea of the direction of some of the first few build-a-bear steps on the average temperature (while the term “average temperature” has some meaning, that is before making the system chaotic).
rgb
Anything with a temperature radiates…in the case of non-spectral gases like N2 or O2, the radiation will arise from inter-molecular collisions. Perhaps we haven’t explored the spectrum at far enough wavelengths to see this emission; perhaps this emission is what helps constitute the entire profile of the “black-body” output curve of the Earth as seen from space in any case.
To clarify this a bit, if one looks at the actual spectrum associated with the cold top of atmosphere, one doesn’t see “CO_2 lines”, one sees pretty much a BB curve, but at a colder temperature in the general IR window. There is clearly a reduction of ground level IR at T_s and its replacement by atmospheric IR at T_a. That’s the physical reality of actual measurements. This is why I have very carefully avoided giving any impression that I “deny” that the “greenhouse effect” or “atmospheric warming effect” in general terms exists.
However, the data tells us something else as well. It is not CO_2 emissions lines. It is well-thermalized emissions from a colder radiator. It clearly does not come from CO_2, which is 0.03% of the atmosphere, recall. It comes from all of the air, well mixed.
That’s why Joe’s treatment kicked off the thought that all that is important is energy transfer, not how it happens.
rgb
Willis Eschenbach says:
January 12, 2012 at 4:32 pm
Thanks. I was almost sure that I was forgetting something. It’s weird that in thinking through complexities, I sometimes forget something obvious that I already know.
RGB, I thank you and others for the comments on this thread.
The spatio-temporal averages simply can’t be depended on to produce accurate approximations to needed quantities. (a) every place on earth has a different temperature from the global mean temperature almost all the time; (b) every place on earth has a different solar irradiance (measured at earth surface and at a higher level subtended by the small earth “place”) almost all of the time; (c) every place on earth has a different radiation, evaporation, advection and convection of energy from the means of these things, almost all the time, and this is true at every altitude. Illustrative calculations show that mean temperature, mean insolation, and mean radiation into space don’t relate meaningfully to each other. Given this, predicting the effect of adding CO2 is impossible at this time; CO2 will have different effects at different times of day, over different parts of earth, at different seasons, and at different altitudes, and a mean effect can’t be computed from some sort of mean (or total) change. As someone else wrote, it is necessary to know all of the rates of energy flow, not their thermodynamic equilibria, in order to estimate/predict the effect of adding CO2 to the present atmosphere. At least that’s what it looks like to me, and I think RGB and others have made the case well.
Stephen Rasey says:
January 13, 2012 at 9:33 am
@eyesonu:
First, from east to west, the geothermal gradient changes from values between 0.025 and 0.03 K/m (0.014 and 0.016F/ft) off the AlabamaMississippi shore to lower values of 0.0150.025 K/m (0.0080.014F/ft) off eastern Louisiana and to higher values of 0.030.06 K/m (0.0160.033F/ft) off western Louisiana through Texas. Second, thermal gradients tend to be lower toward the outer continental shelf (less than 0.02 K/m [0.0112F/ft]). Abstract: Nagihara et al 2008 …………….
===============
Thank you for your response. If the temp gradient were to become less as the outer continental shelf ia approached, would that imply that possibly the heat from the subsurface of the sea floor is being removed by the ocean waters? If so, then the deeper into the ocean that you go (closer to the earth core heat source) could show a lesser gradient that would prove the above suggestion that heat enters the ocean from a ‘hot plate’ effect as considered by richard verney (January 13, 2012 at 3:15 am).
I do not consider this to be completely off topic to the original article/post as the arguments concerning the atmospheric energy budget are all inclusive yet some seem to only focus on incoming solar radiation for a base line and in fact there may be another greater influence here on earth.
This is a most interesting discussion that has now spanned several threads. Keep it coming!
Just noting there are large differences in the looking up (back-radiation) and looking down (emission) spectra when clouds are present.
Low level clouds create a perfect blackbody spectrum for the back-radiation and higher clouds have a little more atmospheric window in them but far, far less than the clear-sky back-radiation spectrum.
When viewing the spectrum looking down from space and there is low cloud, the outgoing radiation is emitting from 10km high at 220K in the CO2 spectrum and otherwise it is emitting from 3 kms high at the cloudtops at 265K.
When clouds are not present, the spectrum is the same 10 kms high at 220K for the CO2 spectrum and now we have atmopsheric windows emitting at 288K or the surface along with water vapour and methane bands emitting at around 250K or 5 kms high.
The spectra are governed by the temperature of the layer where emission starts to become possible directly to space in that particular spectrum.
Clouds make a big difference on the looking up or looking down spectrum and clouds are present up to 65% of the time. Furthermore, nobody seems to know that Modtran has cloud cover options in it (clear-sky is selected as the default) since these options are NEVER charted on the internet.
Tim Folkerts says:
January 13, 2012 at 8:56 am
“And simple satellite data shows that when you look down, you see very nearly 1) a blackbody radiation curve at the temperature of the ground and 2) “bites” taken out of this curve by cooler GHGs high in the atmosphere. There is no “signature” of the cool N2, so there is no noticeable radiation from the N2.”
This is apparent. The question I have is, where does the “bite” get taken out?
What data do we have showing emission curves versus altitude? Is it even possible to determine this?
Is the emission curve from space uniform over the Earth? Or, is it an average over the entire Earth? If it is non-uniform, over what regions is the bite most pronounced?
What accounts for the fact that the two regions before and after the “bite” do not conform to the same blackbody curve (one side is representative of a ~300K isocline, and one ~275K).
And, on a side note, what is the “signature” of radiation from non-GHGs due to collisions? Is it necessarily the same as for spontaneous emission?
Earth Shattering Aha! Moment To Follow
Before reading the balance of my comment, I’d ask that everyone first read (or re-read as the case may be) Joe’s comment upthread:
Joe says:
January 12, 2012 at 11:57 pm
When you have read that and come back, I will explain how Joe’s comment fits perfectly with Nikolov and Zellar, and how the combination of the two answers the vast bulk of the criticisms of N&Z. Now only shall I show how Joe’s explanation of the manner in which the poles act as a thermostat supports N&Z, I shall provide links to observational data that support both their assertions. Please read fast because I’m really excited about this and can hardly wait!
tick tick tick
Welcome back!
I’ll begin by paraphrasing what I consider to be one of two seminal points made in Joe’s comment. The Earth is a net absorber of energy in the tropics, and a net emitter of energy in the high latitude and arctic zones. Joe’s contention that this is the case is supported in spades by observational data. Possibly the easiest depiction of this data that confirms exactly what Joe has said is this graphical representation of Earth’s net radiation as measured by ERBE:
http://eos.atmos.washington.edu/cgi-bin/erbe/disp.pl?net.ann.
As can be seen from this graphic, the tropics are a net absorber of energy, and the poles a net emitter of energy, just as Joe said. In fact, Joe also calculated that the “break even” point between absorption and emission would be 60 degrees latitude, and in fact, ERBE data shows that the approximate breakeven point is about 60 degrees (north and south).
If you’ve followed this far, it shouldn’t be a very big leap from understanding the physics as Joe has explained it to understanding that this is the mechanism to support the existence that provides a thermostatic regulation of the Earth’s temperature, and further, that this thermostatic regulation fits precisely with N&Z, and furthermore explains precisely why the amount of greenhouse gas in the atmosphere is, in fact, immaterial to the equilibrium temperature of Earth. Further, I’ll provide observational data to support that as well, and then tie it all back to N&Z.
From Joe’s comment upthread:
“The primary mechanism responsible for maintaining the incredible 4-billion-year stability of our system must be the physical transfer of heat from the equator to the poles where it is radiated away.”
Precisely. The laws of thermodynamics require this statement to be true. The amount of net loss of energy in high latitudes must balance, to the last photon, the net absorption in low latitudes. Not only does this satisfy the laws of thermodynamics, it also explains why the concentration of GHG’s in the atmosphere is, in fact, immaterial.
Energy is moved from the tropics to the poles to satisfy the energy balance overall by multiple mechanisms. These include oceanic currents, atmospheric currents, and yes, “back radiation” from GHG’s. However, for net absorption to equal net emission, the exact transport mechanism actually doesn’t matter. The latitudes beyond 60 North and South are required by the laws of physics to warm up to a temperature that results in their net emission to space to exactly match the net absorption of the lower latitudes. The exact mechanism is immaterial because the amount that the high latitudes must increase in temperature such that their net loss to space balances the net absorption by the low latitudes is the same regardless of mechanism.
In other words, if the transport mechanism that moves energy from hot (net absorption areas) to cold (net loss areas) was 100% due to GHG’s, thermal equilibrium temperature of the emission zones would be exactly the same as if the transport was 100% atmospheric currents. The mix of transport mechanisms makes no difference to the equilibrium temperature that the high latitudes must reach to satisfy the laws of thermodynamics. Having additional transport capacity (in the form of increased amounts of GHG’s for example) doesn’t change the equilibrium temperature of the high latitudes, it only changes how fast that equilibrium temperature is achieved. The equilibrium temperature itself however, is regulated by the amount of net absorption in the low latitudes that must be balanced by net loss in the high latitudes.
The presence of increased amounts of GHG’s would certainly increase the temperature of the low latitudes by capturing some amount of outbound radiance that otherwise would have escaped to space. But this only serves to alter the path of energy loss to space rather than the amount of energy loss. Since the amount of absorption is NOT governed by GHG’s, neither can the amount of emission be governed by GHG’s. The net increase in temperature achieved by GHG back radiation in the net absorption latitudes does increase the temperature of those areas. That in turn creates a greater temperature differential between low latitudes and high latitudes. The greater that temperature differential, the faster transport mechanisms such as air currents must work. In other words, for every joule of energy that the GHG’s return to earth via back radiation in the area of net absorption, there must be exactly, and precisely, one extra joule of energy moved via any of the other mechanisms (air currents, oceanic currents, etc) to the areas of net loss. The ONLY way for the laws of thermodynamics to be satisfied is for that energy balance to exist.
Increased GHG’s do not change the energy balance because they have nothing to do with it in the first place. All increased GHG’s do is intercept energy that would otherwise have escaped to space directly, and caused a shift in temperature distribution such that the intercepted energy escapes from a higher latitude than it otherwise would have. We can see that this is the case simply by turning to NASA/GISS broken down by latitude. Two years ago I wrote an article on this exact matter. Here is the graph from that article showing global “average” temperature variation versus arctic temperature variation:
http://knowledgedrift.files.wordpress.com/2010/01/global-versus-equatorial-versus-arctic1.png
Note that the rise and fall in temperatures in the arctic zones not only exhibits far greater variability than the rise and fall in global temperatures, but also, that the rise and fall in the arctic zones (this is important) FOLLOWS the rise and fall in global temperatures. In other words, any change that causes global temperatures to increase is only temporary. Since the low latitudes receive the vast bulk of the energy absorbed from the Sun in the first place, any warming, from anything including GHG’s, must result in an increase of temperature differential between the net absorption areas and the net loss areas of earth. That increased differential increased the rate at which energy flows from hot to cold. The increased flow of energy to cold areas lags the initial increase in temperature that began the process, but ends when thermal equilibrium is re-established due to cold areas warming enough to compensate for the increased absorption in warm areas.
In other words, the change induced by changes in (for example) GHG concentrations do NOT change the over all energy balance of the Earth except on a temporary basis. What they DO change is the distribution of the net loss to space, forcing more of it to occur at the high latitudes and less at the low latitudes. Since energy flow in w/m2 varies with temperature in degrees Kelvin raised to the power of 4, this induces a mythical warming trend into the temperature data itself. If the planet is “warming” then there must be an energy imbalance. But since, as I’ve just shown, the energy balance is governed only by the total amount of energy absorbed in the first place, GHG’s only change the place on earth where that energy is lost. Due to the relationship of P to T^4, by moving some of that energy loss to the high (read cold)latitudes, the temperature change as a function of “average” temperature goes up, but the energy balance over the long term doesn’t change at all (except on a temporary basis).
By averaging T instead of T^4, we’ve fooled ourselves into seeing a temperature trend that seems indicative of an energy imbalance. We’re seeing nothing of the sort. What we are seeing is a redistribution of energy about the planet which results in the same exact energy balance which is ultimately governed ONLY by the amount of energy absorbed in the first place!
Averaging T introduces a positive trend that is entirely due to a simple math error. The most colossal simple math error in the history of human kind.
Now back to N&Z. Their equations rely only upon the amount of insolation and the surface pressure to predict “average” temperatures of celestial bodies. The main criticism of N&Z has been that the back radiation of GHG’s is real, and can be measured. By ignoring that, the accusation leveled at N&Z has been that the laws of thermodynamics have been breached.
Nothing of the sort has happened. The laws of thermodynamics require that net absorption and net loss balance, and balance exactly. Any change in the transport mechanisms of energy from cold areas to warm areas (and GHG’s would be one of those mechanisms) is exactly that. A change in the transport mechanism. The net energy balance does not, and according to the laws of thermodynamics, CANNOT change. The ONLY thing that can change is the distribution of that energy loss. As the distribution of the energy loss becomes more pronounced at high latitudes and less pronounced at low latitudes, the practice of averaging T suggests that an energy imbalance is in place and net warming of the earth happening. In fact, all that has happened is that the warm areas of the earth are losing less energy to space directly, and transferring that exact same amount of energy to be released by cold areas instead.
Averaging T produces the illusion of a global warming trend because over the long term, the average of P does not, and according to the laws of thermodynamics, cannot change. GHG’s are immaterial to the average of P. Which is why N&Z are bang on the money, and why all the criticisms of their equations from the point of view of the laws of thermodynamics are completely hollow. The observed data supports exactly Joe’s premise, my premise, and that of N&Z. It is the notion of GHG’s causing a permanent change in the Earth’s energy balance that are the violation of the laws of thermodynamics, and this violation has been completely hidden from view by the shear insanity of trying to measure an average trend of T when we’ve known for over a century that energy balance can ONLY be computed by the average of T^4.
A huge thank you to Robert Brown for laying the foundation for the best rational discussion of the actual physics I have seen to date. Thank you to Joe for providing the clear explanation of the manner in which the high latitudes participate as the ultimate regulators of the earth’s energy balance and for reminding me of the very concept I had proposed two years ago and then forgotten until now. Thank you to N&Z for publishing the formula which I believe will ultimately prevail for many reasons but most importantly, that when you consider their formula within the big picture, it is N&Z that preserve the laws of thermodynamics, and it is the warming attributed to GHG’s that violates them.
And a special thank you to Joel Shore. You and I have carried on a debate tangential to my Aha! moment in multiple threads, and in private correspondence. It got heated a couple of times, but without the challenges you presented to my thought process, I would not have sharpened my understanding of the issues sufficiently to have made the connection between all the pieces presented by Robert Brown, Joe, N&Z, and tied them together.
dmh
HankHenry says:
January 13, 2012 at 10:01 am
On the subject of variability of albedo:
http://www.sciencedaily.com/releases/2004/05/040527233052.htm
It seems scientifically established that earth’s albedo varies.
And from my back-of-the-envelope computation, inverted, that suggests that the average albedo has varied by roughly 0.02 upward. That’s enough to completely cancel even the hypothesized AGW due to CO_2. That’s why the CAGW enthusiasts seem to hate the GCR hypothesis. It’s so strange — you’d think that they’d be happy, the sky isn’t falling and we’ll all live instead of drown and burn in Hansen’s Boiling Seas. It’s enough to eliminate the problem in the worst case scenario, because the increase in albedo can only be due to clouds, and that means that climate feedback due to increased moisture has the wrong sign in their models. Oops.
rgb
Stephen Wilde says:
It isn’t even relevant how the surface temperature gets set: The fact that the surface temperature is such that the surface is emitting ~390 W/m^2 tells us that there must be elements in the atmosphere that absorb some of this radiation.
The ideal gas law does not set the temperature…and it does not determine the lapse rate. If it did, the lapse rate would be at the adiabatic lapse rate in the stratosphere too. The reason that the lapse rate in the troposphere is around the adiabatic lapse rate is a combination of two factors: Radiative (and conduction from the surface) effects that alone would cause an even steeper lapse rate coupled with the fact that lapse rates steeper than the adiabatic lapse rate are instable to convection. Hence, convection occurs and drives the lapse rate back down to the adiabatic lapse rate.
An atmosphere that cannot absorb or emit radiation cannot in any way “inhibit” radiation. You are talking nonsense, not physics.
Robert Brown said @ur momisugly January 13, 2012 at 7:13 am
Like it? I love it 🙂
davidmhoffer says:
January 13, 2012 at 10:54 am
Well done David.
You have just set out in your own words the content of all my work over the past 4 years.
Whatever forcings operate to try to destabilise the global climate the system response is always firmly negative and works via a surface pressure redistribution that alters the relative sizes intensities and latitudinal positions of ALL the permanent climate zones.
That applies whether the forcing in question is oceanic, solar or anthropogenic.
The question then is what difference do human GHGs make in relation to the natural solar and oceanic forcings that shifted the climate zones by 1000 miles or so from MWP to LIA and LIA to date.
I’d be surprised if it were more than a mile or so.
My collected works can be found here:
http://climaterealists.com/index.php?tid=37&linkbox=true
“”””” Myrrh says:
January 12, 2012 at 2:33 pm
Robert Brown says:
January 12, 2012 at 9:00 am
I think it would be very educational to do this and would take the guesswork out of the question “what does water do” or “what does an atmosphere do” to the sphere (relative to superconducting or insulating static sphere).
Why not start from where water has been included?
………………………
And there’s also that forty years ago NASA had to junk Stefan-Boltzmann to get real moon temps estimated for the landings, somewhere on-line, as they needed three dimensions not the flat earth of SB and they had to include that thermal energy absorbed from the Sun penetrated and was released later. “””””
Why is it that many posters here at WUWT throw around “Stefan-Boltzmann” as if it were some universal snake oil elixir, that cures gout, the dts, toe-nail cancer or whatever else ails you ??
“”””” NASA had to junk Stefan-Boltzmann to get real moon temps “””
Total BS, absolute nonsense and moreover, quite false.
Anybody who chooses to “junk Stefan -Boltzmann”, is invited to step up, and get tarred and feathered in the public square; Well of course unless you can present a serious peer reviewed paper setting out your new theory to replace the junked science you chose to discard.
The Stefan-Boltzmann “law”, is nothing more nor less, than a total integral of the Planck formula for the Spectral Radiant Emittance of a BLACK BODY, at a uniform Temperature. Integration is a simple mathematical operation that produces a specific result when applied to a well behaved specific function; so a ceremonial junking of “Stefan-Boltzmann” is synonymous with a junking of the Planck formula for the Black Body Radiation spectrum.
In turn, a BLACK BODY is an entirely fictional theoretical object, that is defined to absorb any and all Electromagnetic Radiation that falls on it; that is radiation of any frequency or wavelength from zero to infinity arriving from any source in any direction. It is NOT defined as any cavity or other geometry; it’s only required property is the complete absorption of ANY incident Electro-magnertic radiation.
No such object exists anywhere in the universe; it is a completely theoretical contrivance.
And decades of very careful experimental measurement of experimental approximations to an ideal black body, over every conceivable wavelength and practical range of Temperatures, has produced measured results that agree with the Planck formula to within the limits of the best experimental practices.
No repeatable systematic deviation from the Planck formula has ever been reported in peer reviewed papers. It is one of the most thoroughly established theories of modern Physics; despite the fact that it relates ONLY to a completely fictional object.
Also, importantly, the Planck formula contains no arbitrary constants or parameters that have to be finagled to get a match with the theory; other than the new fundamental physical constant that it introduces, which is (h) ; Planck’s constant that simply sets the scale of everything in the formula.
So please stop talking nonsense about NASA “junking Stefan-Boltzmann”. They did no such thing; they simply observed, that it does not define the Temperature of the moon. Whoopee, it doesn’t define the Temperature of anything else that is real either.
It is a useful ideal model to use as a starting point in calculating the properties of actual real objects.
“An atmosphere that cannot absorb or emit radiation cannot in any way “inhibit” radiation. You are talking nonsense, not physics.”
Warm air above a surface will reduce the net upward energy flux more than would cooler air above that surface.Temperature differentials are what dictate the rates of energy flux.
Joe Postma said @ur momisugly January 13, 2012 at 9:40 am
And the science is settled. Right…
Jim D says:
January 12, 2012 at 9:32 pm
“It is very simple. Net incoming solar radiation for a spherical earth with albedo 0.3 is 240 W/m2.
Black-body temperature required to radiate 240 W/m2 is 255 K. QED. Any questions?”
Yeah.
Use 1/2 the world.
Put up 100 mile high wall that stops atmosphere. Have earth always face the sun.
So half the world freezes and other half in constant day. Now we have doubled 240 W/m2.
As above we have 480 W/m2 entering and 480 W/m2 leaving.
Such arrangement would change weather and would change climate. Evening and morning parts of world would be cooler. Temperate regions in mid day would become warmer.
And tropics in mid day would remain about the same temperature as any day currently in mid day.. Or generally average temperature may increase. But oceans aren’t going boil. Hot deserts aren’t going to get much hotter.
You are going to disrupt normal weather- and have the severe climate change- fools fear.
One could get repeating patterns, tons rain someplace, and little in others. Trying to predict this seems rather difficult- what part world is constantly facing the sun maybe the biggest variable in terms these numerous possible changes.
But my point is I think average temperature on the sun lit side will not change much.
I am excluding the night side- it obviously will become very cold. And seems obvious that average global temperature would be lower- but that isn’t the issue.
The question is if one doubles the incoming energy [240 to 480 W/m2] for one side, how much effect does have on the sun lit side.
Or does the chance frying eggs on the sidewalk improve?
I imagine if you believe greenhouse effect theory, frying eggs or boiling water on the sidewalk would be how you cook breakfast.
The issue is how much energy does the earth absorb- how much joules of energy.
Obviously per year it’s not much. Compared to each day of warming and cooling- gain and loss,
the daily cycle is losing and gain far more energy than is gained or lost per year.
How many joules on average per day is gained then lost.
Or rotate the walled world, how many joules are gained and lost per day. On each earth half.
If rotating it obviously absorbs far more energy. But anyways how much? In either case.
Energy is moved from the tropics to the poles to satisfy the energy balance overall by multiple mechanisms. These include oceanic currents, atmospheric currents, and yes, “back radiation” from GHG’s. However, for net absorption to equal net emission, the exact transport mechanism actually doesn’t matter. The latitudes beyond 60 North and South are required by the laws of physics to warm up to a temperature that results in their net emission to space to exactly match the net absorption of the lower latitudes. The exact mechanism is immaterial because the amount that the high latitudes must increase in temperature such that their net loss to space balances the net absorption by the low latitudes is the same regardless of mechanism.
I’m having just a bit of difficulty with this, in the context of the extended discussion on radiative balance. Although (as I’ve said) I’m withholding judgement until I’ve done the integrals, it appears to be strictly true that radiative loss is always favored by higher radiation temperature inhomogeneity. In other words, moving heat from the tropics to the poles cools the tropics and heats the poles so it provides a more uniform temperature, but a more uniform temperature is always a warmer temperature on average because in fact you lose heat far faster from the hot tropics than you do from the poles.
In fact, “most” of the net heat (the gain) absorbed during the day in the tropics is lost during the night, at least in any sort of naive static BB model.
Having a bit of epiphany of my own, trying to think of how this could be otherwise, I can think of only one way. If we leave the surface out of it (and for that matter, leave the ocean out of it and everything else out of it) it can increase the mobilization of the heat only by thermalizing the upper troposphere, that is moving heat from the tropics to the poles in the troposphere. In the poles there is an inversion (one visible in the data, incidentally) which slightly warms the ground there but loses the transported heat without reducing the radiative rate at the tropics.
The point is that once one starts to consider the surface and the troposphere as being to independent channels for heat loss, making the tropospheric temperatures more homogeneous by warming them at the poles allows for more rapid heat loss without actually warming the surface commensurately. If you simply warmed the poles at the expense of the tropics homogeneously (at all levels) the more uniform temperature would be net (on average) warmer all things being equal.
Is this not correct? Presuming that there isn’t anything funny that emerges from doing the integrals, of course, matching hot vs cold areas vs their actual temperatures and radiation rates?
More comments later. Life intervenes once again.
rgb
@eyesonu – Re geothermal gradient and heat flow.
Here are two links relating to geothermal heat flow:
SMU Geothermal Lab, US heat flow maps from USGS
Univ. of N. Dakota, Int’l Heat Flow Commission with a valuable Marine data map. The vast majority of marine data points are listed as < 0.1 W/m^2, i.e. 0.5 W/m2 for the ocean in general would require huge heat flow from the rifts that I don’t think is there in the data.
The geothermal gradient is good for estimating temperatures any a given depth in a given area. But without a measure of thermal conductivity, it tells you nothing about heat flow. The Gulf of Mexico is quite cold, largely because the Mississippi River has been dumping huge amounts of sediment into the basin, pushing the isotherms deeper. It is hotter in the GOM where the sedimentation rates are low today and where salt (a good conductor of heat) is rooted.
Correction (darn greater than signs!) “The vast majority….” should read
The vast majority of marine data points are listed as < 0.1 W/m^2, i.e, less than 100 milliwats/m^2. The distribution of points is probably lognormal, so whether the high end tail is over or under sampled is a good question. But even if the mean Ocean Heat flow is driven by rifts, getting the mean above 0.5 W/m2 for the ocean in general would require huge heat flow from the rifts that I don’t think is there in the data.
davidmhoffer says:
January 13, 2012 at 10:54 am
Earth Shattering Aha! Moment To Follow
=============
Great comment. I highlighted “Joe’s” earlier post for a comment of my own but lost the inititive due to the fast moving pace of this thread.
Your summary is spot on!
I believe there is a big hammer falling and AGW will not survive its impact.
Stephen Rasey says:
January 13, 2012 at 11:44 am
=============
Thanks for the info. I will be looking into it. I don’t know the answers, but I have a curious state of mind. Kind of like ” iNQUISITIVE / INQUIRING MINDS NEED TO KNOW”.
Stephen Wilde says:
The way that temperature differences influence net radiation is that two objects at different temperatures and different emissivities radiate different amounts and hence the radiation from the colder object partially cancels the net heat flux from hotter to colder object.
However, you are proposing that this effect still occurs (i.e., the atmosphere reduces the net radiative emission) even if the atmosphere is transparent to IR radiation, i.e., it neither emits nor absorbs it. This is, once again, nonsense…not physics.
Joe says:
>Anything with a temperature radiates…in the case of non-spectral gases
>like N2 or O2, the radiation will arise from inter-molecular collisions.
OK — sounds good. But these effects are MUCH weaker than radiation from molecular vibrations.
Joe then starts grasping at straws
>Perhaps we haven’t explored the spectrum at far enough
>wavelengths to see this emission;
IR spectroscopy is very well studied, so if there were important emissions from N2, they would be known. Besides, for 250-350 K objects, the IR radiation will only be strong in wavelengths of ~ 2 – 40 um. There is no need to look “the spectrum at far enough wavelengths” because the emissions would be too weak to matter.
>perhaps this emission is what helps constitute the entire profile of the
>“black-body” output curve of the Earth as seen from space.
The “entire profile” from the ground is known to be very close to a blackbody curve — nothing must be added to turn it into BB curve. Whatever contributions N2 does make are indistinguishable from the what was already there — ie N2 adds or subtracts nothing that is measureable.
Joe Postma says:
January 13, 2012 at 9:40 am
Anything with a temperature radiates…in the case of non-spectral gases like N2 or O2, the radiation will arise from inter-molecular collisions. Perhaps we haven’t explored the spectrum at far enough wavelengths to see this emission; perhaps this emission is what helps constitute the entire profile of the “black-body” output curve of the Earth as seen from space in any case.
No, it’s been investigated and found to be negligible under the conditions of the Earth’s atmosphere, that’s why we don’t see it. The final speculation is nonsense, just look at the spectrum given above from above Antarctica.
However, there is another important point to consider, which Alan Siddon’s has discussed elsewhere: if the spectraly-neutral gases like O2 and N2 don’t radiate, that means that they collect heat-energy from the solar-heated surface by conduction, and then hang on to that heat: they can’t shed it, they can’t radiate it away spectraly, they just hold on to it. A “GHG”, on the other hand, once having absorbed heat energy from outside into its internal vibration, can then shed that energy by radiating it away. Not being able to lose and radiate the energy away, vs. being able to, should be the difference between a heat-trapping gas and a heat-shedding gas.
That’s the problem with astrophysicists like Postma when they look at the Earth’s atmosphere they think of it as a stellar atmosphere and therefore make elementary errors as Postma has here. Below ~3 scale heights in the Earth’s atmosphere CO2 predominantly loses its excess energy to the surrounding atmosphere by collisions not radiation and thereby warms that part of the atmosphere hence Greenhouse warming. Above that altitude CO2 radiational loss to space starts to win hence the ‘cooling’ of the stratosphere due to GHGs.
Postma, understand the way planetary atmospheres work before modelling them as a stellar atmosphere, the lecture notes recommended above would be an excellent start.
http://maths.ucd.ie/met/msc/PhysMet/PhysMetLectNotes.pdf
In fact, given my perspective from astrophysics, this is exactly the theory that we use to explain how interstellar gas-clouds are able to overcome the thermal response from gravitational collapse (potential energy converts to kinetic = temperature), and continue to collapse to form stars. The spectraly-emitting molecules in the gas (like CO2, but typically CO and others) provide a “vector” through which the thermal energy build-up of the collapsing cloud can escape the cloud. They absorb thermal energy via collision into internal degrees of freedom, then radiate that energy away, out of the cloud. This effectively “damps” the thermal response and then causes cooling. This allows the cloud to collapse into a star.
Yes but we aren’t concerned with a stellar atmosphere here and the ‘perspective from astrophysics’ is wrong! Perhaps you should stick to stars?
Robert Brown;
In other words, moving heat from the tropics to the poles cools the tropics and heats the poles so it provides a more uniform temperature, but a more uniform temperature is always a warmer temperature on average because in fact you lose heat far faster from the hot tropics than you do from the poles.>>>>
EXACTLY!!!
1. Moving heat from the tropics to the poles results in a more uniform temperature.
2. A more uniform temperature results in a higher average T
3. But, a higher average T does NOT necessarily mean a higher average P!
4. Unless a change in any given transport (for sake of argument, an increase in GHG’s) affects the amount of P absorbed, then it doesn’t matter one wit as to energy balance. If it did, the laws of thermodynamics would be breached.
In other words, if average energy absorbed is 240 w/m2, then that’s it. Energy emitted must ALSO equal 240 w/m2. It doesn’t matter if you have 10 ppm of CO2, 100, 1000 or ten thousand ppm. UNLESS the CO2 changes the amount of energy absorbed in the first place, it can have no, none, zero, nada, zippidy doo da, did I mention zero affect on the amount of energy radiated (at equilibrium).
That being the case, the ONLY affect that CO2 can have in terms of GHE is to become part of the mechanism that redistributes energy from the tropics to the poles. CO2 suppresses emissions in the tropics, forcing more energy to be transferred from tropics to poles. The net energy emitted at equilibrium changes not one single fraction of a what. The only thing that changes is that less is emitted at tropics and more at poles.
That in turn results in an increased average T for the exact some P absorbed. No change in energy balance need occur to account for the increase in T.
davidmhoffer says:
There is no data whatsoever that supports your premise. If you actually want to support your premise, I suggest that you:
(1) Show that if one averages T^4 instead of T, the warming seen disappears. Good luck doing that, as Essex & McKitrick (& one other co-author) have already tried…but were only able to get rid of the warming trend seen for an artificially-small set of 12 stations by doing averages of T^n where n get really big. The difference in trend that they got between averaging T and T^4 was small and it will get even smaller if you consider more stations.
(2) Come up with an explanation of how you can take GHGs away and still have the current average radiative emission that the Earth’s surface has.
Congratulations, David. You used to make fun of posters who claimed that the greenhouse effect violates the laws of thermodynamics (and the Second Law specificially). Now you have become one of them…and, like them, you make that claim on the basis of no evidence whatsoever.
I hope you find your full embrace of nonsense more fulfilling than your previous partial embrace.
Stephen Wilde says:
January 13, 2012 at 11:10 am
davidmhoffer says:
January 13, 2012 at 10:54 am
Well done David.
You have just set out in your own words the content of all my work over the past 4 years.>>>
Well I did kinda cheat. I didn’t have to do any original research, it was all done for me and publsihed in various threads on WUWT. All I really did is say hey! all these pieces fit together.
It seems to incredibly obvious. I think the nay sayers are so caught up caught up in how every little detail fits together thah they’ve lost sight of the big picture.
If the Earth absorbes 240 w/m2, then it emmits 240 w/m2. Period. Unless CO2 changes the amount absorbed, then the amount emityteed is 240 w/m2, and it matters not how much CO2 there is or isn’t. the only thing that changes with CO2 concentration is the average of T. The average of T^4 changes not one bit, and hance neither does the energy balance.