Guest Post by Willis Eschenbach
I have a category that I call “scientific urban legends”. These include things like the idea that rising seas will drown atolls, when Darwin showed 150 years ago that rising seas create atolls. Another scientific urban legend is the claim that we’re in the middle of the “Sixth Wave of Extinctions”, when there is no evidence to support that claim. Despite flying in the face of scientific observations, these urban legends show amazing persistence. From my observations in fighting them, each legend will require the equivalent of an oak stake through its heart at a lonely midnight crossroads in order to eventually kill it.
I got to thinking about methane today. It’s supposed to be the doomsday gas of all the greenhouse gases, many times more powerful than CO2. People discuss things like the “methane time bomb”, which is supposed to be ticking somewhere or other, and ready to blow us all to Thermageddon, or at least to the Climatory … the proposed location of said explosive device has changed over time …
So I googled “methane times more powerful co2”, and I got the following top six results, from number one on down:
EPA: 20 times more powerful
EDF: 84 times more powerful
thinkprogress: 34 times more powerful
onegreenplanet: 100 times more powerful
psehealthyenergy: 20 times more powerful
global-warming-forecasts: 72 times more powerful
In those numbers you see an initial confirmation that the methane alarmism actually is a scientific urban legend … one of the red flags for such legends is, nobody knows what the exact number is, but by gosh, everyone is very sure that it is really, really big and really, really bad for us.
So I wondered … the IPCC says that the change in atmospheric absorption from a doubling of CO2 is a 3.7 watt per square metre increase. How much change would there be from a doubling of the methane levels?
To answer this question, I went to the wondrous MODTRAN site. Using todays values for CO2 (~ 400 ppmv) and methane (~1.81 ppmv) gives me upwelling radiation of 287.5 watts per square metre (W/m2).
Then I doubled the methane to 3.62 ppmv, re-ran the calculations, and got 286.7 W/m2 emitted from the TOA …
…
… which means that if by some chance the methane levels were to double in the next hundred years, the total effect would be an increase in the atmospheric absorption of 0.8 W/m2. Less than a quarter of the effect of a doubling of CO2 … say what? This is supposed to be the dread methane, eleventy times more powerful than CO2? Less than one watt per doubling?
So of course, I wanted to check my figures. To do that, I used the formulas from the IPCC for calculating the change in forcing resulting from a given change in methane. They are available here, see Table 6.2. I won’t bore you with the calculations, but they say if the atmospheric methane level doubles from the current level of 1.81 ppmv to 3.62 ppmv, the forcing will increase change by 0.54 W/m2. Somewhat smaller than the 0.8 W/m2 from MODTRAN but the same order of magnitude, well under one watt per square metre …
Let me slow that down for you to make sure you understand what I’m saying. IF methane concentrations double over the next century we would expect and increase in forcing of
One half
Of one watt per square metre
Per century.
So … how likely is it that the methane levels will double within a hundred years? To answer that, we can look at the recent changes in the methane levels. Here is the recent observational data:
Figure 1. Source: NOAA/ESRL
To double from today (1810 ppbv or 1.81 ppmv) would be another 1810 parts per billion. As you can see, the methane levels rose more rapidly until about 1992, and rose roughly linearly at a slower rate after that. The period of record is about a third of a century (36 years). Over that time, it rose by about 250 ppbv. This means that over the next century, with a “business-as-usual” scenario we’d expect something on the order of three times that, or 750 parts per billion. This is a long ways from a doubling, which would be 1,810 parts per billion
And the increased forcing from that 750 ppbv? Well … it’s a measly quarter of one watt per square metre. Again, let me slow that down. With a “business-as-usual” scenario, we would expect an increase in forcing from methane of
One quarter
Of one watt per square metre
Per century
How about if the rate goes wild, and the methane starts rising at say three times the current rate? That would be an additional 2,250 ppbv per century, which in turn will result in an additional forcing of, wait for it … two-thirds of one poor lonely watt per square metre. MODTRAN puts it slightly higher, but still under one W/m2. Pathetic.
And what are the odds of the rate being that high, 2,250 ppbv per century, three times the recent rate of 750 ppbv per century? Very slim. We can see that by looking at the last thousand years of methane levels. Note that these are not global values as in Figure 1. Since there is a methane gradient from the north to the south pole, the Antarctic values are somewhat less than in Figure 1. However, we’re interested in the trend, which will be about the same globally:
Figure 2: Source: NASA GISS
From 1900 to 2000, which was the fastest-rising century in the last millennium regarding atmospheric methane, the concentration went up by about 800 ppbv, a bit larger than the recent increase shown above in Figure 1 of 750 ppbv per century. So there is no acceleration in the rate of methane level increase. To the contrary, there is deceleration, since the recent two decades of the record show an increase of only around 400 ppbv. And indeed, my “business-as-usual” estimate is about as fast as the record rise over the last thousand years.
As a result, I’d say there is very little chance that the rate of methane increase will be doubled, much less tripled, over the coming hundred years … and even in the very unlikely chance that it did triple, the increase in forcing would still be under one watt per square metre per century. Not per decade. Per century.
I gotta say, that’s not some fearsome gas. That’s a downright wimpy example of a Chicken Little gas, a laughing gas if you will. Anyone who is worried about methane, good news. You can stop worrying. Even an extreme methane increase sustained for a hundred years will only make a trivial difference in downwelling forcing. The idea that methane is a major player in the temperature game is a scientific urban legend.
w.
AS USUAL, I request that if you disagree with someone, please quote the exact words that you disagree with. That way, we can all understand just what you object to.
PS—Yes, I know that people claim that methane has some strong feedbacks. And yes, I took a look at them. One is that increasing temperature causes increasing methane, because methane is a byproduct of life, and life likes warmth. More warmth = more life = more decay = more methane.You can see the relationship here.
The problem with that feedback is that whatever increased methane emissions the recent global temperature increase might have caused are already included in both graphs above, Figures 1 and 2. So that feedback is already accounted for in the 750 ppmv/century predicted increase.
The second feedback is due to the fact that methane only lasts about ten years in the atmosphere, at which time it breaks down as follows (simplified):
CH4 ==> CO2 + 2 H20
So when the CH4 is gone, you still have two different greenhouse gases remaining, carbon dioxide and water vapor. Oooh, frightening!
But the problem with that feedback is that the methane numbers are so tiny. The atmospheric levels of the three gases are approximately as follows:
Methane: 1.8 ppmv
CO2: 400 ppmv
Water Vapor: 6,400 ppmv
Now, turnover time in the atmosphere for methane is on the order of ten years. This means that every year a tenth of the methane turns over, or 0.2 ppmv per year.
This means that the amount of methane that decays into CO2 and H20 each year increases the CO2 levels by about 0.2 ppmv per year (or 20 ppmv per century), and the water vapor levels go up by twice that or about 0.4 ppmv per year … meaninglessly small.
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In the interests of preventing the release of more terrifying methane, is it not essential that we ensure that the forests of planet earth are immediately burned to the ground and desertified.
As a precaution, to prevent vegetable matter from falling and slowly rotting on the forest floor.
It may seem like a high price to pay, but we need more forest clearance and desertification.
Everybody knows that deserts don’t release much methane, except for the odd farting Bedouin.
Alternatively, we could just load all vegetable and animal material, (including surplus people) into cages on vast barges and take the whole lot out to sea and dump the whole lot, weighted down of course, into a major geological subduction zone.
We won’t see any of that material again, until it is blasted out of a neighboring volcano.
That would leave just a small happy population of remaining humans living on a planet that resembled Mars.
The eco-left wants radical solutions. Well they should ask me for help.
I’m all for the precautionary principle – especially when it may allow us to subduct some eco-zealots, along with their stupid cats and organic granola.
Another advantage to destroying all the forests is that they will then be unable to emit the VOC’s (terpenes etc) which lead to ground level ozone. Double plus good!
For those concerned about runaway methane emissions from methane hydrates, Richard
Corfield wrote an interesting article in “Chemistry in Britain”, May 2002 issue “Close
Encounters With Crystalline Gas”.
This article cites research about a massive destabilization of CH4 hydrates at the P-E
boundary
According to readings from cores drilled Blake Plateau by leg 164, the age of the hydrates
retrieved were “precisely 55m years old.
My conclusions from the article are:
Hydrates are very stable over time. The earth has been very much warmer than it
is now and as well as very much colder and the hydrates did not move from their
zone of stability, so minor warming at the end of this inter-glacial period will do
nothing.
It is further my opinion that the mass extension event at P-E was caused by a comet or
large meteorite impact which caused a great amount of mechanical heat to be
introduced to the inner earth and that heat or the shock and vibration or both
caused the massive release of methane hydrates from its zone of stability.
The hydrates appear to be a threat only after we are all already doomed.
I have not been able to find the e form of the above cited article and my hard
copy is a copy of a copy.
Willis, is not your description of these myths as “urban myths” also now described as “factoids”? That is, a factually untrue statement that is repeated so often that it becomes generally accepted as factual. That is – Goebbels style??
Brian J in UK
Water absorbs in the same region of Earth’s outgoing infra red radiation as methane does. Most calculations of methanes effect ignore the presence of water.
At average atmospheric water concentration of 2.5% 25000 ppm, then there are 14700 water molecules per methane molecule. So that infra red photon has one chance in 14700 of hitting the methane.
A graph of total absorption by all green house gases in the 7 to 9 µm range shows that water absorbs virtually all of the infra red in that region.
Care to produce that graph Peter? There are very few water lines in that region of the spectra compared with methane:
http://i302.photobucket.com/albums/nn107/Sprintstar400/WaterCH4.gif
Most calculations using line spectra use the full spectra for each species.
Why have you picked such a tiny part of the spectrum?
Well Phil, I thought I saw one of those methane lines that falls exactly on one of the water lines but damned if I can find that again. Must have been seeing things.
Now the striking difference in complexity between your two samples, begs the question.
Why is the water one so sparse, and the CH4 one so dense ? I presume that QM explains all of that. If I had to hip shoot (totally dangerous), I would guess that the asymmetry of H2O limits the options (that 104 deg. thing), while CH4 I presume is quite symmetrical, with a lot of duplications. But as I said, just a WAG.
G
Billy Liar October 12, 2015 at 4:03 pm
Why have you picked such a tiny part of the spectrum?
Because that’s the region where CH4 absorbs and where the original poster claimed that H2O dominated CH4.
George E. Smith October 12, 2015 at 4:51 pm
Well Phil, I thought I saw one of those methane lines that falls exactly on one of the water lines but damned if I can find that again. Must have been seeing things.
I’m sure some do George, you’ve got 3000 H2O lines and 30,000 CH4 lines to choose from. 🙂
Now the striking difference in complexity between your two samples, begs the question.
Why is the water one so sparse, and the CH4 one so dense ? I presume that QM explains all of that. If I had to hip shoot (totally dangerous), I would guess that the asymmetry of H2O limits the options (that 104 deg. thing), while CH4 I presume is quite symmetrical, with a lot of duplications. But as I said, just a WAG.
Basically yes, there are many H2O lines but they are spread out over a large part of the spectrum.
George, here’s a good website that shows the different modes for both CH4 and H2O which think you’ll find useful. (For CH4, 3N-6=9 whereas for H2O it’s 3)
http://www.chemtube3d.com/vibrationsCH4.htm
Phil,
Thanks for that web site. I can always use more sources of information. Being not a chemist, then the QM of these molecular line spectra, are all a mystery to me. I have forgotten most of the atomic spectra stuff I learned in school too long ago to even remember.
I’m still mystified to some extent by BB radiation or “Thermal” radiation in general, because the molecular line spectra are a function of the electronic structure of specific molecules, whereas BB radiation, and thermal radiation are independent of any real material properties.
So Planck, and Einstein (or was it Bose) said E = hf or h(nu), but they place no restrictions of any kind on the value of f or nu that is permissible, so in effect, the photon energy can be any value whatsoever; and to that extent, it isn’t quantized; and you have a continuum spectrum.
Nobody seems to doubt the continuum spectrum from ionized atoms because the captured electron can have any value of initial energy. But I find (some) people continue to insist that Black Body radiation is also quantized (in energy), even though no real material with real electronic structure, is involved. But of course, ordinary gases are so low in molecular density, they aren’t even close to total absorbers of all EM radiation, so they certainly aren’t BB emitters.
I have papers on continuum emission from gas atoms and molecules, without a dipole antenna to radiate, but during collisions, these papers argue that the electron distribution is distorted during collisions, so that they do have a radiating antenna while they are distorted. But the Planck BB radiation derivation assumed no material specific electronic structure to really quantize any energy levels.
E = h.f allows for ANY value of f, not just discrete values dictated by structure; only accelerated electric charge (varying electric current) is needed.
But thanks for that energy level diagram for CO2.
G
It is so easy to alarm peoble. The numbers 20 to100 for methane is when you compare the effect of 1kg of CO2 extra to 1kg of methane extra.
One kg methane extra means a lot more relative increase than does 1 kg of CO2.
In that way you can claime this dramatic effect, but Willis way is more realistic.
Willis,
Thanks for an interesting post. I applaud your conclusion that methane is nothing to worry about. However, I think even you have over-stated its impact.
Honoring your request to state the exact words in your post that I have a problem with, here they are:
“To answer this question, I went to the wondrous MODTRAN site. Using todays values for CO2 (~ 400 ppmv) and methane (~1.81 ppmv) gives me upwelling radiation of 287.5 watts per square metre (W/m2).
Then I doubled the methane to 3.62 ppmv, re-ran the calculations, and got 286.7 W/m2 emitted from the TOA …
… which means that if by some chance the methane levels were to double in the next hundred years, the total effect would be an increase in the atmospheric absorption of 0.8 W/m2.”
I understand that CO2 and methane are both radiative gasses and that they emit LWIR radiation ‘isotropically’ i.e. in all directions equally – upwards as well as downwards. This means that at any point in time, 50% or so of their emissions are upwards into space, where they are lost forever. Consequently, if the amount of CO2 or methane in the atmosphere is increased by humans, the amount of LWIR emissions lost to space would also increase. If this happens, the planet as a whole must cool as a result – not warm! This logic to me seems pretty solid, though I may be missing something in which case please explain what that might be.
In my humble opinion, I believe you are interpreting your MODTRAN results incorrectly. You state that the upwelling at TOA reduces by 0.8 W/m2 when methane is doubled, because of increased absorption by the atmosphere, implying that the temperature down below is higher as a result. I would interpret the MODTRAN result the opposite way. The TOA emissions are lower by 0.8 W/m2 because the temperature below is lower. The temperature below is lower because of the increased LWIR emissions into space! The lapse rate has changed and the atmosphere is at a new equilibrium at a lower average temperature. The lower temperature then causes the resulting TOA emissions to be lower.
By the way, I have raised this issue several times before on WUWT and usually get a response of crickets. If I am right, the impact of increasing methane is not just small – it is negative!
Please help me understand where I am going wrong.
Bernard Lodge October 12, 2015 at 12:41 pm
I understand that CO2 and methane are both radiative gasses and that they emit LWIR radiation ‘isotropically’ i.e. in all directions equally – upwards as well as downwards. This means that at any point in time, 50% or so of their emissions are upwards into space, where they are lost forever. Consequently, if the amount of CO2 or methane in the atmosphere is increased by humans, the amount of LWIR emissions lost to space would also increase. If this happens, the planet as a whole must cool as a result – not warm! This logic to me seems pretty solid, though I may be missing something in which case please explain what that might be.
One factor is that the excited state of the methane molecule is of the order of millisec whereas the collisions with other air molecules occur about 10 times/nanosec, therefore low in the atmosphere collisional deactivation is a major route for the absorbed energy. Even not allowing for this less of the energy leaving the surface makes it to the TOA if it is reradiated from the CH4 molecules. For every W leaving the surface absorbed by CH4 only 0.5W reaches the TOA, absorb more and the amount leaving the TOA goes down. However for an energy balance the same amount of energy must leave the TOA as leaves the atmosphere, using MODTRAN as Willis and I did in order to deal with this you have to increase the surface temperature to return the TOA flux to the former value. In order to balance the doubling of methane to 3.62 ppm the ground temperature increases by ~0.23ºC.
Thanks for the reply Phil which I found very helpful. However, I do not understand one aspect of you comment. I hope you will persevere with your explanation ….
You wrote …
“However for an energy balance the same amount of energy must leave the TOA as leaves the atmosphere, using MODTRAN as Willis and I did in order to deal with this you have to increase the surface temperature to return the TOA flux to the former value”.
Why do you have to return the TOA flux to the former value? That was my main point, the TOA flux would be expected to reduce due to the lower average temperature of everything below TOA.
Perhaps the answer to my confusion is in the first part of your sentence where you say “for an energy balance, the same amount of energy must leave the TOA as leaves the atmosphere”. I’m not sure what you mean by this. I assumed the total upwelling emissions at TOA were all leaving the atmosphere by definition – no matter what the flux level was. Do you mean something else?
I understand that collisional deactivation is a major route for absorbing energy as well as photon absorbtion. In other words, all atmospheric molecules heat up as a result of collisions with other molecules or absorbtion of photons. Similarly, all atmospheric molecules (in fact all matter) emit electromagnetic radiation photons at varying wavelengths. Both mechanisms transfer heat generally upwards; kinetic energy through convection and radiative energy through direct emission. The photons may bounce up and down many times but they are moving at the speed of light so very quickly any that are not absorbed are lost to space. These photons don’t just come from CO2 and methane, every molecule of matter emits them, including the other atmospheric gasses.
I feel that I must still be missing some logic on the energy balancing topic as it still seems to me that more CO2 and methane will lead to more emissions into space which must reduce temperatures below TOA! I appreciate any help you can give with this.
However for an energy balance the same amount of energy must leave the TOA as leaves the atmosphere
Typo sorry, should be “enters the atmosphere from the sun”
“In order to balance the doubling of methane to 3.62 ppm the ground temperature increases by ~0.23ºC.”
Thanks Phil. I repeated the MODTRAN calculation as you proposed and got the same result for the tropical atmosphere. I don’t know to what extent horizontal and vertical heat transport is included in the MODTRAN calculation. Therefore I compared the results of my gridded EBM model with MODTRAN. I found from MODTRAN that the absorbance of the atmosphere in the IR increases from 0.740 to 0.743 for doubling the CH4 concentration (1.8 to 3.6 ppm). In my calculation, the global surface temperature increases by 0.46 °C, if the other parameters (albedo, atmospheric absorption, convective heat transport etc.) are held constant. However, tiny changes of these other parameters can compensate this temperature increase.
Bernard Lodge October 12, 2015 at 5:57 pm
Thanks for the reply Phil which I found very helpful. However, I do not understand one aspect of you comment. I hope you will persevere with your explanation ….
I’m glad you found it helpful.
You wrote …
“However for an energy balance the same amount of energy must leave the TOA as leaves the atmosphere, using MODTRAN as Willis and I did in order to deal with this you have to increase the surface temperature to return the TOA flux to the former value”.
Sorry about that typo which I’ve corrected. Basically in balance the same amount of energy incident from the sun must leave the TOA, if it does not then the earth system will either heat or cool depending on whether there’s a surplus or a deficit.
I understand that collisional deactivation is a major route for absorbing energy as well as photon absorbtion. In other words, all atmospheric molecules heat up as a result of collisions with other molecules or absorbtion of photons. Similarly, all atmospheric molecules (in fact all matter) emit electromagnetic radiation photons at varying wavelengths. Both mechanisms transfer heat generally upwards; kinetic energy through convection and radiative energy through direct emission. The photons may bounce up and down many times but they are moving at the speed of light so very quickly any that are not absorbed are lost to space. These photons don’t just come from CO2 and methane, every molecule of matter emits them, including the other atmospheric gasses.
Assume for simplicity that our atmosphere has just a nitrogen atmosphere, the surface will heat up until the amount of energy leaving to space balances that incoming. The energy leaving will be entirely black body from the surface since N2 doesn’t absorb at the relevant wavelengths. Run MODTRAN with all the GHGs zeroed out (CO2, CH4, O3, H2O).
Now add a greenhouse gas which is transparent in the visible but absorbs in the IR and has a very short radiative lifetime, i.e. it emits IR within a nanosec of absorbing it. In this case virtually all the energy absorbed by the molecule is re-emitted, on average about one half goes up to space and one half towards the surface. This will cause less radiation to leave in the absorption range of that gas. (Repeat the MODTRAN expt with a GHG added (say CO2)). On the MODTRAN run you’ll see that less energy is leaving than formerly so offset the temperature until it’s the same energy loss as before, this will increase the surface temperature.
In a real GHG like CO2 the radiative lifetime is much longer than the collision frequency so energy is transferred to the surrounding gases thereby warming the atmosphere, so in that case even less light would leave through that spectral window and the surface would get even hotter. Most of the collisionally excited gases are not able to emit significantly in the rotational and vibration bands. Even a CO2 molecule is extremely unlikely to emit when collisionally excited because there are very few molecules with enough kinetic energy to populate the necessary vibrational level for emission. Even when one does the high energy molecule would have to hit the vibrational ground state CO2 molecule in exactly the right orientation to induce the excited state vibration, again very unlikely.
Hope that helps.
Morning Phil, Now I am seeing a model more in line with my undergrad days (and some later serious work on heat transfer in solids and vacuum). Thanks for the effort. It would be good (for me anyway) to look at a slightly different starting atmosphere. Say, 78% nitrogen + 22% oxygen. Would the modification make a significant difference?
grumpyoldman22 October 13, 2015 at 3:37 pm
Morning Phil, Now I am seeing a model more in line with my undergrad days (and some later serious work on heat transfer in solids and vacuum). Thanks for the effort. It would be good (for me anyway) to look at a slightly different starting atmosphere. Say, 78% nitrogen + 22% oxygen. Would the modification make a significant difference?
If it were just those two then no significant difference but because of the UV absorption by O2 ozone is formed so adding another GHG. The MODTRAN calculations of course are based on a N2/O2 atmosphere but you have the ability to switch off the O3.
Phil,
Thanks for additional explanation and the typo correction – both helped further my understanding. It’s been a while since I ran the MODTRAN model and I won’t be able to get back to it for a week or so, so I will have to pause this discussion and come back to it in a future thread – I will look for your posts to do that.
I would say though that I do have some questions about the way MODTRAN is used. For instance, a satellite in orbit looking down and measuring the full electromagnetic spectrum sees the familiar emittance curve that we know has dips in the various absorption wavelengths. The satellite does not know that below it is a planet with an atmosphere, there could be other reasons why there are dips in the spectrum. It just measures the EM energy it receives which represents the average temperature of the planet below – approximately 15 C. If the satellite turned its sensor to the sun, it would receive a totally different spectrum of EM radiation equivalent to approximately 5500 C. In other words, the TOA radiation is a function of the temperature below. If TOA energy comes out lower, it comes out lower because the temperature is lower! I never understood the need to assume the surface is warmer to make it ‘balance’ again.
I will continue to ponder and research that seeming contradiction. Thanks for your comments and I do appreciate your willingness to take the time to teach on WUWT.
Using your logic, radiation from the ground is interrupted and half of it is re-radiated back. If it weren’t for CO2 and CH4, that radiation would go straight to space without being interrupted. In other words, the heat would escape faster without CO2 and CH4 so the planet would cool. So, yes, CO2 and CH4 should make the planet warmer (following your logic).
The above description is way over-simplified. ONE of the issues is that CO2 and CH4 usually bump into other molecules and lose energy that way rather than radiating the energy. That means the energy moves from a quantum state to being merely kinetic energy. The atmosphere as a whole warms up and convection probably increases. … A naive application of the physics equations doesn’t cover the situation.
There’s an outside chance that you could even be right about CO2 and CH4 cooling the atmosphere but for the wrong reason. (apologies to Charlie Chan)
Thanks for the reply commieBob.
I do appreciate that there is a kinetic effect as well as a radiative effect. My point is that at any given concentration of CO2 and methane, both the kinetic and radiative effects will combine to result in a certain amount of emissions into space. If the concentrations of those (more radiative) gasses increases, the radiative emissions to space must logically also increase. If the energy inputs from the sun remain the same, the temperature of the planet must go down!
Since the atmosphere of Venus is largely CO2, your logic would predict that it would be quite frigid.
Balloon and satellite measurements show that the main effect of CO2 is to remove energy at around 15 um. link There’s no evidence that CO2 increases the amount of energy radiated by the planet.
commieBob,
No, Venus is hotter than the Earth because it’s atmospheric pressure is 100 times greater than on the Earth, not because its atmosphere is mostly CO2.
I said that at any given concentration of CO2 and methane, both the kinetic and radiative effects will combine to result in a certain amount of emissions into space. If the concentrations of those (more radiative) gasses increases, the radiative emissions to space must logically also increase. Venus emits whatever it emits as a result of the kinetic and radiative effects of its own atmosphere. If a more radiative gas was added to its atmosphere, it too would emit more radiation to space and be cooler than it would otherwise be.
You are right that CO2 absorbs at around 15 um. That is also the wavelength that it emits. Increasing CO2 will increase both absorption and emission – 50% of the latter will eventually be lost to space.
If you want evidence that CO2 increases emissions into space, look at Willis’ MODTRAN results in his piece. Where do you think the emissions go?
Possible hotter due to proximity to the sun, and size?
Bernard; when you say “all atmospheric molecules heat up as a result of collisions with other molecules or absorption of photons.” you are skating on thin ice.
” All ” is a word of your choice. If they ALL heat up, by collisions, you have a never ending spiraling Temperature rise.
If one molecule “heats up” assuming there is meaning to that statement, some other molecule must “cool down” also assuming there is meaning to that statement.
Temperature is implicit in both of those statements, but Temperature is a macro-thermodynamic property of very large assemblages of “particles”, presumably atoms or molecules. Any single molecule has no defined Temperature.
The equi-partition principle implies that the total energy of such an assemblage of molecules is on average spread equally among all of the available degrees of (mechanical) freedom. I believe it is kT/2 per degree of freedom, where k is Boltzmann’s constant.
I have made an argument; for which I can claim no peer support whatsoever, that in any fixed sample quantity of a gas, which presumably is at a single uniform Temperature, the individual molecules are distributed in energy according to the Maxwell Boltzmann distribution, as a function of that Temperature. Over time (I have asserted) any single molecule, will occupy every possible energy level in that distribution, as a result of collisions with its neighbors.
If that is true (I claim it is), then one can say that over time, the KE of any single molecule will exhibit the same Maxwell Boltzmann distribution, that applies to the sample of gas; and therefore we can say that an individual molecule has a time averaged “pseudo-Temperature” that is equal to that of the gas, and has over time the same MB energy distribution.
But at any instant of time, in between collisions, any molecule in free flight has no definable Temperature.
So any “heating” or “cooling” that is going on WRT any molecule, is only a consequence of net energy input from some other source; either from an EM field, or from the introduction of a sizeable assemblage of other molecules which are at a different Temperature.
Individual molecules are NOT heated by collisions with other molecules. They exchange energies, in a process not unlike billiard balls in collisions.
Well the QM afficianados, have a weird view of billiards, and molecular collisions as well.
They might be right.
g
It goes without saying, that at any instant of time, we have no idea what the “Temperature” of any single molecule is, we can only learn that as a time averaged value.
Of course the Queen of all Maxwell’s demons; My “Mother Gaia” can read the serial numbers on each individual molecule, so she knows exactly what the (pseudo)Temperature of each one is .
So she always gets the Global Temperature correct. But she won’t tell us what it is !!
Don’t forget that energy thief, Entropy.
George, thanks for your reply and for sharing your theory. When I say “all atmospheric molecules heat up as a result of collisions with other molecules or absorption of photons”, I mean that those are the two ways that a body heats up. I agree that they are both just transfers of heat from somewhere else. I like the analogy that heat is represented by the degree to which molecules vibrate. Vibration/heat is either caused by collisions with other molecules or by absorption of photons. Cooling happens when the amount of collisions reduces or more photons are emitted than absorbed, resulting in less vibration. By the way, all matter emits photons at all wavelengths, with the distribution curve changing according to its temperature. Since the amount of vibration of a molecule (its temperature?) is constantly changing due to collisions with other molecules plus photons being absorbed or emitted, it seems to fit with your theory!
Bernard Lodge October 14, 2015 at 3:19 pm
By the way, all matter emits photons at all wavelengths, with the distribution curve changing according to its temperature.
Not true in the gas phase.
The energy of photons is quantized, there are three types of energy levels, electronic, vibrational and rotational. In our atmosphere gas molecules are in the ground electronic state, within that state there are multiple vibrational energy levels and within those levels multiple rotational levels. Usually most molecules are in the ground vibrational state. In order to be promoted from the electronic ground state a UV photon of exactly the correct energy is needed, IR excites vib-vib transitions, microwaves excite rot-rot transitions. When a CO2 molecule is excited by an IR photon to a particular higher vib/rot state then it will lose energy by either emitting a photon or have it chipped away by multiple collisions. The emission can only occur at discrete wavelengths corresponding to the energy difference between the upper level and a lower one, it does not occur at all wavelengths. Only molecules with a dipole such as CO2 can absorb/emit at such wavelengths, homonuclear diatomics such as O2 and N2 do not have a dipole and therefore do not emit in the IR range.
The following diagram shows an example, in which v indicates a vibrational level and j indicates a rotational level and the resulting spectrum, note the gaps!
http://hyperphysics.phy-astr.gsu.edu/hbase/molecule/imgmol/hclspec2.gif
Here’s an energy level diagram for CO2:
http://www.barrettbellamyclimate.com/userimages/PQRCO2.jpg
Here’s the corresponding spectrum:
http://www.barrettbellamyclimate.com/userimages/CO21M.jpg
Phil,
Thank again for your another very helpful post. Especially your statement that the gas phase is so different with regards to energy transfer. You keep raising new questions and it will take a while for me to catch up and understand those points but I will focus there next. My objective is to properly understand how CO2 can be a ‘more radiative’ gas than others in the atmosphere get somehow not result in more radiation to space. Intuitively, that doesn’t seem to make sense.
Perhaps you might consider posting an in depth review and explanation of the MODTRAN model as a featured WUWT essay? It seems you, Willis and others routinely use it to prove your points when discussing the warming effect of CO2? I think many WUWT users would find that incredibly interesting.
That black painted window: Does it get warmer than the unpainted one, when in sunlight? Can you feel warmth radiating from it from a few mm away? Would it, um, be re-radiating?
I have never actually painted a window black, but my guess is that the glass will get hot and radiated in the infrared…in both directions.
Sorry…radiate in the …
Willis,
I know I already asked about this, and am surprised that no one else seems to have mentioned it, so maybe I am not understanding the terminology. I had thought perhaps it was a typo.
When you wrote:
Did you mean to say that every year , rather than every decade, a tenth of the methane turns over?
I was on my phone earlier, and for some reason I cannot make the clipboard work on the darn thing, so providing an exact quote as you request was difficult. Sorry about that.
Thanks.
Menicholas, I’m sorry I missed your comment. You are 100% correct. I’ve fixed the calculations in the head post.
Many thanks. I always encourage people to be skeptical about everyone’s work including mine. Thank you for doing so.
All the best,
w.
“albondigas”. Geez I had to look that up in your last post, Willis. I laughed out loud. Now I know what it means, but I can’t use it in a sentence yet.
You’re the best, thanks for a great article.
As a curiosity, wouldn’t an increase in methane in the atmosphere lower the available oxygen as well? At what point does the level of oxygen in the atmosphere become a concern? Is it possible that the lowering of oxygen might, then, trigger an extinction process, at least for animals?
http://s11.postimg.org/qt4vzvq2b/Sun_Earth_Comparison.png
Finally found the graph that tells the story. Even to my cataract eye, the blue area is greater than the red. The area in each colour represents energy in and out. Energy out >> Energy in appears a contradiction unless core energy loss is added in. Can’t ignore the energy thief Entropy either which takes energy out of the equation at each energy transformation.
The effect is the Earth shows net cooling despite the best efforts of UN IPCC. Core heat is finite and will reduce over time, I suspect moving the bulge in the blue to the right (IR). Perhaps someone in UN will realise they have been promoting the wrong units (T°C) for their great scam. If the UN had chosen T°K, no one would have given a toss anyway.
It will not be really felt until sometime in the future when we may not recover from an ice age as we have managed so far.
Ah, Yes. Climate has been changing, is changing, and will continue to change. But not according to Prof Rosco Guano’s (famous Canberra economist and mining magnate) and fellow traveller Prof Tom Foolery’s settled science.
The red curve looks off by a factor of about ten!
http://www.patarnott.com/satsens/images/TOAsolarFlux.gif
Beware, looks can deceive. The red curves look the about same if similar scales are used. By ‘off’ do you mean too large an eclosed area or too small? Similarly the blue inset curve has similar shape to the one in my post except it too has been scaled to omit the best bit.
The data sources appear different too. I think my red curve relates to earth surface and yours top of atmosphere. Not sure of to where your blue curve applies but the high magnitude figures tend to support my claim that more energy leaves than arrives from the Sun.
Are we comparing camels and cows?
The red curve (insolation) you posted peaks at 250 W/m^2/micron whereas the one I posted peaks at 2200 W/m^2/micron. The blue insert is just the fine detail of the peak. Albedo effects would only reduce this by about a third at the surface.
OK, your blue curve puzzled me.
My observation was that solar energy reaching the Earth surface (peak 250 W/m^2/micron red curve) suggests that about 300 W/m^2 reaches our surface. The blue curve in my pair of graphs suggests about 600 W/m^2 leaves.
To consider the same situation at the top of the atmosphere would require a second curve for energy leaving. Be interesting to compare the two estimates. The red curve you give for insolation at the top suggests about 2300000 W/m^2 arrives.
The red curve you give for insolation at the top suggests about 2300000 W/m^2 arrives.
If you integrate the curve the area under the curve comes to ~1200 W/m^2, which is about what’s expected, albedo gives about 70% reaching the surface, 850 W/m^2.
Looking at a typical emission spectrum from the TOA
Absent any GHGs the earth’s surface at 280K emits ~130 W/m^2/sr.
Include the GHGs you get about 120 W/m^2/sr with a surface Temp of 320K
https://directory.eoportal.org/image/image_gallery?img_id=218018&t=1339757099635
I’ve only just seen this posting and wonder if some kind soul with photoshop on their computer could add a Santa hat to the cow on the heading and perhaps a bit of snow in the background and post it, as I think it would make a great xmas card urging friends to warm their houses this winter by keeping a cow in the house and enjoy an eco-friendly Christmas. Or perhaps “What the cows think about AGW this Xmas” etc
JohnKnight October 14, 2015 at 7:00 pm Edit
Thanks, John. Let me start by recommending that you read my responses to Knute here and here. They cover many of the points you raised.
As to the idea that science is a blood sport, the reason it is a blood sport is that the essence of science is one person showing that another person’s scientific theories, which are often deeply held and have been passionately defended, are 100% wrong … and that is indeed a blood sport, because the man’s entire life’s work and occupation and perhaps even identity are often wrapped up in his theory. Which someone has proven wrong. So passions do indeed tend to run high.
As to your incorrect idea that the comment by Dinostratus is “silly”, you’ve come in in the middle of the story. In fact his comment is one more in a long string of his ugly unprovoked ad hominem attacks on me.
And my experience, based on writing literally hundreds of posts on this site and trying out various responses to the inevitable attacks, is that if I follow your advice and I do not oppose such attacks, they tend to fester and grow, with more and more people seeing that there is no cost to attacking me so they jump in to join the attack on my personal honesty, my abilities, and my scientific reputation.
And I can ill afford damage to my scientific reputation, because I have little else. I have none of the usual scientific tokens. I have no job in science, nor have I ever had any. I have no colleagues to confer with. I have no university standing behind me, and no university library access. I have no scientific education except for introductory physics and chemistry. I have no graduate students to assist me. I have no PhD, no MS, no BS. And while I do have five journal articles, including a “Brief Communications Arising” in Nature magazine, that’s hardly an impressive amount. Well, it impresses me, because I know the price I’ve paid to be able to come up “through the hawsehole” and to do it entirely on my own … but that pales in comparison to folks like Dinostratus, who likely have some long string of papers and they have all the scientific tokens of jobs and education and the like.
So I will not sit by and allow people to drag my reputation through the mud.
Now, if you have tested out a better solution than mine to that problem, please point to the post(s) where you’ve tested that solution, so we can see just how well it works.
And if you haven’t tested your solution … then why are you pushing an untested solution, particularly on a man like myself who has already tested your solution and found it wanting?
So no, John, I won’t simply stand still and allow some anonymous viper to make unpleasant ad-hominem attacks designed to impugn my good name. That just encourages them, and it invites others to join in the hatefest. You are free to do that if you wish … me, I’ve tried it, and all I got was my reputation besmirched while I stood and watched and made no protest.
Am I happy with my solution? By no means. It is merely the lesser of the two bad choices. Call me crazy, but I’d rather be busted for too vigorous a defense of my reputation than sit by idly while someone tears it down and stomps on it.
My best to you, and thank you for your kind comments about the article.
w.
Willis
Did you get permission to double link me ?
That was a joke. Stop.
Put down the throat puncher.
It’s good to hear you explain it’s not an ideal choice but the only one that works for you. I still like the “quote me if your going to challenge me” boundary. I think it works well in the written forum.
In the wacky world of nonsense, it’s hard to be both the calm composed fallacy identifying machine and the effective throat puncher all at once. It think it exhausts the brain. Well, at least my brain. I find it’s good to have an objective observer by one’s side. I hope you have one from time to time.
My heels have scars from the nipping and some days I think lopping off the heads of the useless wasn’t all that bad an idea.
Reblogged this on Climatism and commented:
Another great read on ‘Methane’ causes global warming, alarmist campaign.
“Anyone who is worried about methane, good news. You can stop worrying.”
Reblogged this on gottadobetterthanthis and commented:
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I’m often inclined to reblog Willis, but this one is just for the numbers, just for the reference. I’ll point back to it when challenged regarding methane.
As usual, W. just reduced all this into a simple problem that could be addressed through Google, ignoring all the associated complications such as those given in this paper for example. http://www.nature.com/nature/journal/v507/n7493/full/nature13164.html
Thanks, Rob. The paper you cited quotes the scare numbers (“25 times the global warming potential of carbon dioxide (CO2)” … YIKES!), but they don’t mention that a) the chances of atmospheric methane doubling in the next century is quite small, and b) even in the unlikely event that methane doubles it will make only a very small difference in the forcing.
I’m sorry if that is too simple for you.
w.