Guest Post by Willis Eschenbach
[Update: I have found the problems in my calculations. The main one was I was measuring a different system than Kiehl et al. My thanks to all who wrote in, much appreciated.]
The IPCC puts the central value for the climate sensitivity at 3°C per doubling of CO2, with lower and upper limits of 2° and 4.5°.
I’ve been investigating the implications of the canonical climate equation illustrated in Figure 1. I find it much easier to understand an equation describing the real world if I can draw a picture of it, so I made Figure 1 below.
Be clear that Figure 1 is not representing my equation. It is representing the central climate equation of mainstream climate science (see e.g. Kiehl ). Let us accept, for the purpose of this discussion, that the canonical equation shown at the bottom left of Figure 1 is a true representation of the average system over some suitably long period of time. If it is true, then what can we deduce from it?
Figure 1. A diagram of the energy flowing through the climate system, as per the current climate paradigm. I is insolation, the incoming solar radiation, and it is equal to the outgoing energy. L, the system loss, is shown symbolically as lifting over the greenhouse gases and on to space. Q is the total downwelling radiation at the top of the atmosphere. It is composed of what is a constant (in a long-term sense) amount of solar energy I plus T/S, the amount of radiation coming from the sadly misnamed “greenhouse effect”. T ≈ 288 K, I ≈ 342 W m-2. Units of energy are watts per square metre (W m-2) or zetta-joules (10^21 joules) per year (ZJ yr-1). These two units are directly inter-convertible, with one watt per square metre of constant forcing = 16.13 ZJ per year.
In the process of looking into the implications this equation, I’ve discovered something interesting that bears on this question of sensitivity.
Let me reiterate something first. There are a host of losses and feedbacks that are not individually represented in Figure 1. Per the assumptions made by Kiehl and the other scientists he cites, these losses and feedbacks average out over time, and thus they are all subsumed into the “climate sensitivity” factor. That is the assumption made by the mainstream climate scientists for this situation. So please, no comments about how I’ve forgotten the biosphere or something. This is their equation, I haven’t forgotten those kind of things. I’m simply exploring the implications of their equation.
This equation is the basis of the oft-repeated claim that if the TOA energy goes out of balance, the only way to re-establish the balance is to change the temperature. And indeed, for the system described in Figure 1, that is the only way to re-establish the balance.
What I had never realized until I drew up Figure 1 was that L, the system loss, is equal to the incoming solar I minus T/S. And it took even longer to realize the significance of my find. Why is this relationship so important?
First, it’s important because (I – Losses)/ I is the system efficiency E. Efficiency measures how much bang for the buck the greenhouse system is giving us. Figure 1 lets us relate efficiency and sensitivity as E = (T/I) / S, where T/I is a constant equal to 0.84. This means that as sensitivity increases, efficiency decreases proportionately. I had never realized they were related that way, that the efficiency E of the whole system varies as 0.84 / S, the sensitivity. I’m quite sure I don’t yet understand all the implications of that relationship.
And more to the point of this essay, what happens to the system loss L is important because the system loss can never be less than zero. As Bob Dylan said, “When you got nothin’, you got nothin’ to lose.”
And this leads to a crucial mathematical inequality. This is that T/S, temperature divided by sensitivity, can never be greater than the incoming solar I. When T/S equals I, the system is running with no losses at all, and you can’t do better than that. This is an important and, as far as I know, unremarked inequality:
I > T/S
or
Incoming Solar I (W m-2) > Temperature T (K) / Sensitivity S (K (W m-2)-1)
Rearranging terms, we see that
S > T/I
or
Sensitivity > Temperature / Incoming Solar
Now, here is the interesting part. We know the temperature T, 288 K. We know the incoming solar I, 342 W m-2. This means that to make Figure 1 system above physically possible on Earth, the climate sensitivity S must be greater than T/I = 288/342 = 0.84 degrees C temperature rise for each additional watt per square metre of forcing.
And in more familiar units, this inequality is saying that the sensitivity must be greater than 3° per doubling of CO2. This is a very curious result. This canonical climate science equation says that given Earth’s insolation I and surface temperature T, climate sensitivity could be more, but it cannot be less than three degrees C for a doubling of CO2 … but the IPCC gives the range as 2°C to 4.5°C for a doubling.
But wait, there’s more. Remember, I just calculated the minimum sensitivity (3°C per doubling of CO2). As such, it represents a system running at 100% efficiency (no losses at all). But we know that there are lots of losses in the whole natural system. For starters there is about 100 W m-2 lost to albedo reflection from clouds and the surface. Then there is the 40 W m-2 loss through the “atmospheric window”. Then there are the losses through sensible and latent heat, they total another 50 W m-2 net loss. Losses through absorption of incoming sunlight about 35 W m-2. That totals 225 W m-2 of losses. So we’re at an efficiency of E = (I – L) / I = (342-225)/342 = 33%. (This is not an atypical efficiency for a natural heat engine). Using the formula above that relates efficiency and sensitivity S = 0.84/E, if we reduce efficiency to one-third of its value, the sensitivity triples. That gives us 9°C as a reasonable climate sensitivity figure for the doubling of CO2. And that’s way out of the ballpark as far as other estimates go.
So that’s the puzzle, and I certainly don’t have the answer. As far as I can understand it, Figure 1 is an accurate representation of the canonical equation Q = T/S + ∆H. It leads to the mathematically demonstrable conclusion that given the amount of solar energy entering the system and the temperature attained by the system, the climate sensitivity must be greater than 3°C for a doubling of CO2, and is likely on the order of 9°C per doubling. This is far above the overwhelming majority of scientific studies and climate model results.
So, what’s wrong with this picture? Problems with the equation? It seems to be working fine, all necessary energy balances are satisfied, as is the canonical equation — Q does indeed equal T/S plus ∆H. It’s just that, because of this heretofore un-noticed inequality, it gives unreasonable results in the real world. Am I leaving something out? Problems with the diagram? If so, I don’t see them. What am I missing?
All answers gratefully considered. Once again, all other effects are assumed to equal out, please don’t say it’s plankton or volcanoes.
Best wishes for the New Year,
w.
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Bryan says:
You should be able to find a copy of Science at any reasonable local library. The basic picture is that CO2 alone provides about 20% of the radiative greenhouse effect (with the other non-condensable greenhouse gases providing another 5%). Water vapor and clouds (condensed water vapor) provide the other 75% with the division being water vapor ~50% and clouds ~25%. However, if you remove the non-condensable greenhouse gases, then the resulting cooling causes the amount of water vapor in the atmosphere to plummet because of the strong dependence of the saturation pressure on the temperature.
“Common sense” is not always a very good guide when talking about things that one really hasn’t developed much intuition for.
JAE says:
It is quite a jump from writing down the ideal gas law (pV = nRT), which involves 4 variables, to explaining how this constrains the surface temperature. I have never seen anyone successfully make that jump…and I predict it would be quite difficult to do so, since it seems impossible to violate the constraint of energy balance for very long.
If the earth’s surface were warmer than energy balance predicts (in the absence of IR-active gases in the atmosphere) then it would emit more radiation than it receives and it would cool down. It is as simple as that. There are ways to get around that, e.g., by having constant gravitational collapse…but I would doubt you would want to make the argument that the earth or its atmosphere are undergoing continuous gravitational collapse!
On subjects like this it seems to me that some basics of heat transfer should be available to new comers etc so they can start to grasp the questions surrounding the discussion.
Such as for heat to be transferrd there must be two basic requirements.
1. a path
2. a gradient
Without out these two regardless of the mechanism no heat is transferred.
I know folks can look up much themselves,but maybe a section on the site where they can quickly go to get info maybe be helpful.
Bryan says:
January 5, 2011 at 1:00 am
Bryan says, Joel Shore;
“What would happen if one of the models was left to run with the IR radiative effects of CO2 shut down?”
“H2O still operating with radiative properties in the IR and the usual phase change effects still intact.”
Not sure who said what re Joel and Bryan.
What would happen is commonly referred to as “Snowball Earth” which has happened several times in the earth’s history. The water cycle shuts down. The earth’s average surface temperature without greenhouse gases is way below freezing. CO2 with sufficient partial pressure raises (through its effect as an insulator) the surface temperature above freezing which in turn starts the water cycle. Once the water cycle is started water vapor takes over as the primary greenhouse gas raising the temperature even more until there are enough albedo-lowering clouds to prevent any further warming of the surface.
If CO2 were suddenly absent water vapor would continue to keep the surface warmer than freezing for a while but eventually the ice would win, the water cycle would be shut down, and average temperature would plunge below that of the moon (moon’s average temperature is -23C) because snow and ice has a far higher albedo than lunar regolith.
Indeed it is commonly believed that CO2 build-up during a Snowball Earth episode is what eventually melts the frozen surface. When the earth is covered with ice and snow the water cycle isn’t the only thing that shuts down. The carbon cycle shuts down as well. Volcanism continues and over the course of millions of years CO2 being belched out of volcanoes accumulates in the atmosphere. On a frozen earth there is nothing to remove CO2 from the atmosphere. No plants, no chemistry, no liquid water on the surface to absorb any of it. Eventually it reaches a high enough partial pressure to defeat the ice and the melt is rapid.
At a CO2 partial pressure of 280ppm (presumably the average over the last few million years) any minor perturbation is enough for snow and ice to start building further and further downward from the poles. A mere 3 degree cyclical change in axial tilt which does nothing more than increase/decrease the temperature difference between winters and summers is enough to start and stop interglacial/glacial periods.
The only “tipping point” we’re near today is tipping back from interglacial to glacial. Wanting to reduce or limit atmospheric CO2 is the same as wanting to push the planet over the edge back into a full blown ice age that will persist for 100,000 years and cover everything north of Washington, DC with a glacier that’s a mile thick. It’s insane.
Dave Springer
…..”What would happen is commonly referred to as “Snowball Earth”…….
……”If CO2 were suddenly absent water vapor would continue to keep the surface warmer than freezing for a while but eventually the ice would win, the water cycle would be shut down”……
There are about 40 H2O molecules to each CO2 molecule on average.
In addition to having even more radiative possibilities in the IR, water also has two phase changes at atmospheric temperatures.
The absence of a CO2 radiative component would mean that the Earth Surface would be warmer during daylight.
In my hypothetical atmosphere CO2 would still be there but would not radiate at around 15um.
Vegetation and so on would behave as the temperature dictated.
The question was addressed to Joel Shore because I suspect he has access to a model and I was wondering if such a run had been attempted and what the outcome was.
Dave Springer, thanks for the graph, regarding the water, your point. But I won’t buy the CO2 cycle without seeing it experimentally confirmed.
BTW, I like most of your explanations here.
Too much detail too fast. If you can’t get close to the observables with a few basic robust factors, there’s no chance to explain it further. All this worry about thermoclines, tropospheres, back raditation, etc. will not solve the problem as to whether there’s AGW due to CO2 or not. If one needs to employ these arguments, then there isn’t an argument. Look how complicated the human body is. But you don’t need a detailed dissection of human anatomy to know that the more calories you eat and the less you work out, the heavier you become. Sure you can talk about the ATP cycle and metabolising glucose and the role of vitamins and burning energy in muscle tissue and storage in fat tissue, etc. But really adding food calories above the burning rate explains a lot of what’s going on. You start there and dig deeper as needed. The fact that AGW needs to pull in all this detail to try and patch together a story tells me that they don’t have a clue what’s going on with the climate. Not a clue at all.
Dave, Springer,
“No. False. What you should do is admit you made a mistake. Seawater density increases constantly until it freezes and the freezing temperature is about 2 degrees C below zero. Not knowing that led you to say that the deep ocean temperature is 3C because that’s the point of grestest density.
Man up and admit you made a mistake.”
Deary, deary me. Well, I do try to be careful about what I write, but nobody’s perfect. Let’s see…
Could you take a look at my comment here and quote for me the exact text where I say:
a) the water in question is seawater;
b) that seawater density does not increase all the way to freezing point;
c) the deep ocean temperature is 3C;
d) the deep ocean temperature is what it is because that is the point of “grestest” density?
I’m particularly interested in the answer to part a), because my intention at the time was to talk about water generally, without specifying salt or fresh. I’m interested to know what I said that made you so certain that I was only referring to salt water, so I can avoid the error in future. Thanks in advance.
If everybody here had to apologise for all their errors, all the threads would be about twice as long. I shall look out for your response with interest.
@ur momisugly Dave Springer
““That seems to be nonsense to me. Shallow pools of water heated by the sun are demonstrably warmer than deeper pools with the same surface area. For particularly deep bodies, with not a lot of turbulance, you can end up with a scenario where the top couple of feet are much warmer than the lower areas.”
The sun isn’t heating them with thermal IR.
Heat diffuses through the entire portion via conduction and brownian motion, in addition to the non-IR heating element (visible light -> IR.) So yes, some IR is heating the water.
According to your theory, I can point a heat lamp at a bathtub and the water will remain room temp.
Jon-Anders Grannes says:
January 5, 2011 at 12:24 am
“This means on average that the more column of air you have above you the warmer it gets.”
That depends on the gases present and the radiative spectrum at that level in the atmosphere. In more of the atmosphere than not (by column feet) temperature increases with altitude.
See here:
http://www.srh.noaa.gov/jetstream//atmos/atmprofile.htm
If you understand why the stratosphere temperature increases with altitude almost as quickly as the troposphere decreases with altitude you’ll then understand why increasing partial pressure of N2 and O2 at the surface won’t raise or lower average surface temperature. All it will do is reduce the temperature differential between day and night via increased thermal mass.
As long as climate science relies on cartoonish conceptions of thermal energy fluxes largely through radiative means, puerile misconceptions of how surface temperatures are elevated above nominal blackbody levels will run wild.
Although radiation provides the only escape for energy to space, the TOA balance is not the core issue at the surface, where moist convection is the principal means of thermal energy transfer to the atmosphere on an oceanic planet. Colin Davidson (Jan 4, 4:13am) summarizes the physical problem very well. I only add the observation that the “inert” bulk constituents of the atmosphere, once thermalized by convection and by molecular collisions with GHGs, provide (along with clouds) what little “thermal inertia” the atmosphere posseses; it is very small compared to that of the oceans.
The GHGs act as a dispersant rather than a store of thermal energy, with outward as well as backward radiation at every level. Despite Kiel and Trenberth’s propagandistic portrayal of backradiation as the principal source of thermal energy at the surface, it is simply part of a nearly null-net radiative exchange with the insolation-warmed surface, with the latter invariably stronger on climatic scales. It’s the surface that warms the atmosphere, not the other way around.
What the presence of any atmosphere does is provide a gaseous envelope into which thermal energy from the thermalized surface can conduct and convect, thereby buffering the temperature differential between the surface and space. Since all matter at temperatures above zero K radiates, regardless of the composition of the atmosphere there will always be backradiation that effectively retards radiative cooling of the surface. The density of the atmosphere, which is a factor in its enthalpy, and the surface heat capacitance are what really matters. Mars, with ~16 times more CO2 molecules between its surface and space, but less than one percent of Earth’s atmospheric density, shows very little “greenhouse effect.” It’s not a matter of radiative algebra.
That’s all, folks!
Joel Shore at 5:39 am says:
“It is quite a jump from writing down the ideal gas law (pV = nRT), which involves 4 variables, to explaining how this constrains the surface temperature. I have never seen anyone successfully make that jump…and I predict it would be quite difficult to do so, since it seems impossible to violate the constraint of energy balance for very long. ”
Please read: http://www.buzzle.com/articles/how-hot-is-venus.html
Here’s another one:
http://www.ilovemycarbondioxide.com/pdf/Rethinking_the_greenhouse_effect.pdf
Dave Springer and Joel Shore
How come with your “snowball” earth concern you had not noticed that increased CO2 follows increasing temperature.
It is a lagging factor not a causal one.
This fact is now generally acknowledged and is a current feature article in of all places Skeptical Science.
While agreeing this is the case they make some convoluted attempt to show its still the ever guilty CO2s fault.
The BBC tonight were at the usual spin saying the record cold December is due .to Global Warming.
Cold is hot,up is down,black is white,effect is cause,lagging is leading.
“”””” kcrucible says:
January 5, 2011 at 8:54 am
@ur momisugly Dave Springer
““That seems to be nonsense to me. Shallow pools of water heated by the sun are demonstrably warmer than deeper pools with the same surface area. For particularly deep bodies, with not a lot of turbulance, you can end up with a scenario where the top couple of feet are much warmer than the lower areas.”
The sun isn’t heating them with thermal IR.
Heat diffuses through the entire portion via conduction and brownian motion, in addition to the non-IR heating element (visible light -> IR.) So yes, some IR is heating the water.
According to your theory, I can point a heat lamp at a bathtub and the water will remain room temp. “””””
Well I doubt that much “heat” is transported by Brownian Motion; which is the observed eratic motion of small airborne particles like dust or pollens; that is well known to be the result of such particles being sufficiently small and low in mass, that they are capable of registering even a single molecular collision with air ; rather than responding blankly to just the average of those random molecular collisions. And as for this :- “”””” According to your theory, I can point a heat lamp at a bathtub and the water will remain room temp. “””””
Well not exactly; a “Heat Lamp” actually emits EM radiations that the human body (because of its water content) actually recognises as “heat”; those being wavelengths in the range from about 750 nm to about 4.0 microns, right in the range where “heat lamps” emit much of their energy.
BUT ! we are talking about the ocean (or surface) being warmed by a LWIR Thermal Radiation source (the atmosphere) that has a mean Temperature of about 288K (+15 deg C or +59 deg F), and emits about 390 W/m^2 in a spectrum centered at about 10.1 microns, and ranging from about 5.0 to 80.0 microns for 98% of its energy emissions. A very good laboratory source approximation to the real atmopsheric source, would be an ordinary sixteen ounce or about 250 ml bottle of drinking water. Your “heat lamp” on the other hand could be emitting as much as 4 megaWatts per square metre, in a spectrum centered at 1.0 micorns rather than ten microns. Humans cannot even sense 10 micron radiation as being “heat”; in fact we have to jump through hoops to detect it at all.
Try heating your bathtub, using a real LWIR radiation source such as a bottle of drinking water.
Bryan says:
January 5, 2011 at 7:24 am
Zeroing out the non-condensing greenhouses gases results in average surface temperature decline to -20C in the first decade using GISS ModelE AR5. Lacis did it, published the results, and discusses it below:
http://pielkeclimatesci.wordpress.com/2010/11/03/guest-post-co2-the-thermostat-that-controls-earth%E2%80%99s-temperature-by-andy-lacis/
I have no argument with it. Where I think the model boffins go wrong is that the so-called thermostat has a floor temperature set by non-condensing greenhouse gases (consistent with the model above) but where the ceiling temperature is set by cloud cover not by greenhouse gases where increasing surface temperature causes more clouds which then raises planetary albedo which then limits further surface warming. This is not how clouds are modelled and therein lies the major flaw in the vaunted global circulation models.
“”””” Joel Shore says:
January 5, 2011 at 5:39 am
Bryan says:
Unfortunately it is behind a pay wall and written by the “usual suspects”.
I cannot tell therefor if their prediction of the end of all human life is justified.
Common sense tells me that the consequences of such a minor change would be negligable.
You should be able to find a copy of Science at any reasonable local library. The basic picture is that CO2 alone provides about 20% of the radiative greenhouse effect (with the other non-condensable greenhouse gases providing another 5%). Water vapor and clouds (condensed water vapor) provide the other 75% with the division being water vapor ~50% and clouds ~25%. However, if you remove the non-condensable greenhouse gases, then the resulting cooling causes the amount of water vapor in the atmosphere to plummet because of the strong dependence of the saturation pressure on the temperature. “””””
But Joel, if your “plummeting” water vapor scenario is correct; and remember that even ice sublimes when the atmospheric humidity is very low (see the “Snows Of Kilimanjaro”); then with the atmosphere devoid of H2O, we presumably would no longer have what NASA recently asserted was an average global cloud cover of 61%; so we would have a significantly smaller cloud albedo contibution; and absent H2O vapor in the air, we would get less near IR (0.75-4.0 microns) absorption of incoming solar energy, so the ground level solar insolation would skyrocket; and since 70% of the ground is the oceans; and even a higher percentage than that in the more tropical regions; the ocean storage of solar energy would blossom, and the near surface absorption of that 0.75 to 4.0 micron solar energy, would tend to warm the near surface layers, and we would not be wanting for water vapor in the atmosphere for very long.
Your snowball earth sans NCGHGs scenario, is a product of the nonsensical belief that the TSI is 432 W/m^2 instead of 1366 W/m^2.
Given the lousy thermal conductivity of planet earth; the planet surface responds to the instantaneous solar energy input; not to the global annual average insolation.
There are plenty of locations on this planet, whose Temperatures routinely fall below 255 K; the supposed BB equilibrium Temperature sans the GHG effect; and those locations continue to accumulate plenty of snow; which allegedly falls from the sky; and they have plenty of clouds; and all the CO2 that man has polluted the air with have failed to raise those Temperatures above the “water ignition point”. For some reason the air gets plenty of water even at Temperatures below 255K; so why isn’t the CO2 lifting the Temperature in those regions. I thought global warming was most prominent in the polar regions; so why is it still so cold there ?
“”””” Jon-Anders Grannes says:
January 5, 2011 at 12:24 am
?
Radiation goes from warm to cold. Never from cold to warm. “””””
Well (EM) Radiation doesn’t know anything about Temperature; which is entirely a property of MATTER, so Radiation acn go pretty much anywhere it wants to.
That includes the roughly 3 K (spectrum) background radiation from the “Big Bang” having no trouble landing on the 6,000 K surface Temperature of the sun.
EM Radiation is NOT “heat”. And the second Law of Thermodynamics applies to cyclic machines; a la Clausius: ‘No cyclic machine can have no other effect than to transport heat from a source at one Temperature, to a sink at a higher Temperature.’
Bryan says:
Chickens are also a “lagging factor” of chicken eggs. However, that does not mean that they are not a cause of chicken eggs. Causality can work both ways…and we in fact know that CO2 has radiative effects that can be calculated quite accurately (even if the feedbacks introduce considerably more uncertainty as to its final effects).
It is true that in the absence of humans rapidly liberating the carbon stored for eons in fossil fuels, there had to be some sort of trigger for the increase of greenhouse gases in the atmosphere…and during the glacial-interglacial cycles, that trigger was provided by the Milankovitch oscillations in the earth’s orbit and the resulting warmings this caused that then led to the release of CO2 into the atmosphere. However, the timing is such that the CO2 can still be responsible for a considerable fraction of the warming (and seems necessary to explain the synchronization of the two hemispheres). Estimates of the forcings involved suggest that CO2 was responsible for about 1/3 of the warming between the last glacial maximum (LGM) and now, with all the greenhouse gases together pushing that number up to about 40%.
George E. Smith says:
Skyrocket? I think that is a little strong. At any rate, what mainly matters is the top-of-the-atmosphere energy balance (because of the strong mixing by convection and latent heat in the troposphere), which won’t be affected considerably by exactly where the absorption occurs.
And, do you have evidence that any of these effects were left out of the models? Surely, they modeled how clouds will change. (The estimates that I have seen on clouds is that they currently raise the earth’s albedo from about 12% to about 30%.) However, there are also changes in albedo due to the increase of ice.
George: Things are modeled at various degrees of approximation. For a simple energy balance model, one looks at the average insolation over the surface. However, the full-blown GCMs don’t make this approximation. They have the diurnal cycle and the albedo effects of clouds and so forth. Try googling “climate models diurnal cycle”.
And, do you have any evidence that climate models predict that they will? Again, George, you are just making nonsensical complaints. You are creating strawmen that have no basis in reality. The models don’t actually predict what you seem to think they say will happen.
I’ve lost you here. The prediction is that an increase in the greenhouse effect will manifest itself more strongly near the poles. It is not that the poles will be warmer than tropic regions. Again, George, you are just creating strawmen of your own devising.
sky says:
January 5, 2011 at 10:13 am
“The density of the atmosphere, which is a factor in its enthalpy, and the surface heat capacitance are what really matters. Mars, with ~16 times more CO2 molecules between its surface and space, but less than one percent of Earth’s atmospheric density, shows very little “greenhouse effect.””
The usual answer to the weak greenhouse effect on Mars is lack of anything for CO2 to thermalize by conduction. On the earth where the atmosphere is 100 times thicker when a CO2 molecule is excited by 15um IR it immediately bumps into a molecule of nitrogen or oxygen and transfers part of the energy to those molecules. The so-called back radiation comes primarily from conductively heated nitrogen and oxygen. On Mars there’s very little conductive heat exchange going on because the separation between molecules is far greater. CO2 there absorbs and holds what little heat it can and the rest is lost to space.
Jon-Anders Grannes: January 5, 2011 at 12:24 am
kai: January 5, 2011 at 1:37 am
Dave Springer: January 5, 2011 at 9:16 am
All of you are so close to the answer but in various aspects leaving out critical points here and there that confuse the discussion.
All should be wary of the atmosphere. It does some non-intuitive tricks on you. I’ll try to explain what I see you may be missing that would put you all parallel.
Does everyone think PV = nRT holds in the lower atmosphere, I do. So Dave, Jon-Anders is correct in his statement, the lower you go with more pressure the higher the temperature, walla, the lapse rate without getting into which gases are present.
But you have another effect happening at the same time, due to gravity. The higher pressure when lower in altitude has many more molecules per volume at an also elevated temperature so to equalize the temperature the molecules must slow to a degree. This creates a molecular velocity gradient that *will* try to equalize but curiously can never be really reached but it really is just an change in the conductivity vertically in addition to the radiative gradient due to the temperature difference. All molecules will also try to equalize their velocities between vertical shells. To me that is the one prime relation underlying general thermodynamics, the velocity of the molecules.
But in a paper defining the “standard atmosphere 1976” there is a plot, no numbers, of molecular velocity with altitude and the velocity is going up markedly with altitude. So the velocity equalization would be DOWNWARD, Not what I expected. That would mean there is a certain amount of energy tendency downward against the temperature gradient. Seems to violate t.d. principles but there it is. In this case to me it’s merely a decrease or even negative conductivity with altitude. Looked in isolation its warmth moving downward, not the net flow, but it would decrease it.
At some factor there is a ‘net mean molecular velocity gradient’ also imprinted in the atmosphere when looking at various altitude levels in relation to each other.
Any of you see that area I’m speaking of. It’s left out of all discussions I read. That is one other factor that is not radiative in nature in the migration of energy upward.
Not being *that* good in t.d., I can seem to follow this thought much deeper, maybe you can. Maybe it’s just another factor best tossed out the window and inappropriately ignored.
George E. Smith’s explanation (January 5, 2011 at 5:39 am) was easy for me to understand. But Joel Shore’s answer comes across as gibberish in places.
For example, he talks about the energy balance ”which won’t be affected considerably by exactly where the absorption occurs.” Won’t be affected considerably by exactly… ? What does that mean?
And he criticises using the word skyrocket, when he himself uses the word plummeting. It seems Mr. Shore has an axe to grind here, specially when he says Mr. Smith is just “making nonsensical complaints”. I think Mr. Smith’s explanation was good, and it wasn’t a complaint.
Mr. Shore’s comments suggest that GCM’s make good predictions. But from what Ive read they don’t. Good predictions are the real test of models. But models can’t predict with any accuracy. Maybe that’s why Mr. Shore is so testy.
The more I read this site the less I believe there’s any climate problem.
@sky (con’t)
I can’t say I’m completely satisfied by the above explanation for weak greenhouse effect on Mars. So as usual in such cases I dug a little deeper. In the search for contributing factors I took a look at typical night time minimum surface temperatures. Both Vikings measured -107C (160K) at night. Since the peak emission frequency shifts with changing temperature I wanted to see if that shifts the peak spectral energy away from CO2 absorption wavelengths.
A blackbody at 160K has a peak emission wavelength of 18um. See:
http://www.spectralcalc.com/blackbody_calculator/blackbody.php
CO2 absorption bands are 2, 3, 4, and 15um. The night time surface on Mars thus radiates practically no energy in the 2um to 5um range and (compared to the earth) diminished energy in the 15um region. This must undoubtedly contribute to the weak CO2 greenhouse effect on Mars – the surface emission spectrum on Mars isn’t as well aligned with CO2 absorption spectrum as it is on the earth’s surface.
“”””” Joel Shore says:
January 5, 2011 at 12:26 pm
George E. Smith says: “””””
Joel, absolutely nowhere in my post did I refer to what any computer models do or do not predict, project, or otherwise indicate. I don’t care what they get in the way of output from those models; since none of it seems to have happened so-far.
I merely pointed out that on a real planet like earth, that rotates. the FULL solar energy input acts on the regions that currently are in sunlight; not some isotherrmal blackbody calculation for an infinite thermal conductivity body might experience.
So clouds only raise earth’s albedo from about 12% to about 30%; well that’s hardly anything we would notice is it; it’s not like a 1/100th of a degree Temperature rise; excuse me Temperature anomaly would do to increase the frequency and severity of hurricanes, and tornadoes.
As for the albedo contribution of ice. Take a guess Joel; c’mon I know you can do it; Why do you think there is all that ice in the polar regions; I mean we don’t have ANY ice to speak of in the tropics where most of the sunlight is; so just how much solar energy is going to be rejected from the earth surface because of that polar ice. If clouds only increase albedo from 12% to 30%; hardly worth mentioning; why would anybody mention ice albedo.
Who cares a whit Joel about the top of the atmosphere energy balance ? The vast majority of earth’s energy is stored and captured in the oceans, directly from solar spectrum sunlight. And that happens to be in the general neighborhood of where humans and other living things tend to congregate and thrive. And the total integrated sum of all of that energy is ADVERSELY affected by each and every single H2O molecule in the atmosphere, no matter where geographically or altitudinally, nor in any way dependent on the phase of that H2O sample. It ALWAYS reduces the ground level total solar energy input to the earth; no IFS ANDS OR BUTS. Whether condensed, or in vapor form, no matter whether you just exhaled it, or whether it is waiting for a 200 year old CO2 companion to exit the atmosphere with; WATER ALWAYS reduces the total energy received by the earth from the principal energy source; the sun.
And it is that surface energy which ultimately determines the thermal transport processes which eventually escort some of that energy to the upper atmosphere to be lost to space. Most of the thermal radiation from earth originates at the surface; and a good bit of it escapes without ever paying any attention to conditions at the top of the atmosphere; and additional radiation losses pass through one or more atmospheric absorption/emission cycles before escape; but that energy starts mostly at the surface. True direct solar heating of the upper atmosphere can result in somewhat prompt loss to space; that’s a significant part of the solar energy input that never makes it to the surface because of H2O; and of course also to Ozone; well even CO2 that arch enemy of all living things, contributes to cooling the earth by capturing some small percentage of the near infra-Red solar radiation and preventing it from reaching the surface.
I would recommend Joel that you should apply for research grants to study what is actually happening on a real planet like the earth for instance; and stop paying attention to the output of some supercomputer’s backwards looking Global Circulation Model. Do they have any Global Climate Models; well besides Trenberth’s isothermal energy balance cartoon ?
I don’t care (one iota) what ANY computer model predicts about what has happened in the past; how many of those models can predict the already recorded Temperature anomalies for all (or any) of the surface stations where GISS or HADCrut data have been gathered. Oh I forgot; the models don’t use the same grid of data points that anybody actually measures any data for.
If you don’t think that a change in albedo from 30% down to 12% due to cloud loss would cause earth’s surface insolation to “skyrocket”, then Joel, I think I might have to re-evaluate my impression of your expertise.
Now a half a degree (C) possible (who knows) increase in mean global surface Temperature over the last 150 years; would in my book, NOT be described as a “Skyrocket” change; but the effect of clouds dropping the albedo from 30% to 12% (your figures) would fit the bill for me.
“”””” I’ve lost you here. The prediction is that an increase in the greenhouse effect will manifest itself more strongly near the poles. It is not that the poles will be warmer than tropic regions. Again, George, you are just creating strawmen of your own devising. “””””
The above from Joel.
I don’t have a problem with the assertion that the poles should warm faster than the tropics. After all the polar temperatures can be so low, that thermal radiation rates are a factor of as much as six lower than the rates for places at earth’s mean Temperature of (supposedly) 288 K So the polar regiosna re near useless for cooling this planet because of those low emission rates. Then because of those same lower Temperatures, the spectrum of that weak polar thermal radiation is moved to longer wavelengths, so that eventually at the coldest places, the spectral peak can sit right on the 15 micron absorption band of CO2 and hence maximise the GHG capture effect of CO2 at the poles.
Conversely in the highest Temperature tropical desert regions; where surface Temperatures of 333K or higher are seen; the thermal emission rates can be 1.8-2.0 times the global mean rates, and more than ten times the puny polar rates.
And moreover, because of those higher source Temperatures in the tropics, the emitted LWIR spectrum moves even further away from the 15 micron CO2 band making CO2 even less effective in its greenhouse effect. And for an encore, the peak of the tropical desert surface emission spectrum moves even further into the middle of the atmospheric window, that is largely due to H2O absorption band spectra; but since water vapor is largely absent over those same d3eserts; there’s not much to impede the exit of the peak of the LWIR emissions from hot deserts. They are the most efficient (radiative) coolers on the planet.
Yes I know that convection and evaporation and other thermal processes are responsible for most of the energy transport in the atmosphere; come to think of it; just what role does CO2 in the atmosphere play in interrupting conduction and convection and evaporative cooling processes from the earth surface ?
I wonder why everybody makes such a fuss over the greenhouse gas phenomenon of CO2 and methane; when it is well known that Electro-magnetic radiation is but a small part of the earth’s energy transport processes; and CO2 has no impact at all on the most prevalent energy transport physical processes.
But as to the initial paragraph of your puzzlement Joel.
Is it NOT true; that you are a disciple of the theory that CO2 is a greenhouse gas which acts as a “kindling wood” (my words) to magically kick off the previously dormant H2O evaporation process; which leads to H2O (which is NOT a greenhouse gas; since it condenses); AMPLIFYING the LWIR absorption by CO2 in a positive feedback loop ? And without that CO2, well there simply would be no H2O in the atmosphere so earth would be a frozen ice ball at around 255 K Temperature. That’s what that was all about; that so puzzled you.