Guest post by John Kehr from: The Inconvenient skeptic
There are many times when I am putting together articles that I need to compare the results of my research to the models of the theory of Anthropogenic Global Warming (AGW). In this manner I can contrast the results and predictions directly. This way I understand how the different views relate to each other.
Recently I was trying to find the total amount of energy (forcing) that the warmists claim CO2 is responsible for in the atmosphere. The reason I wanted this is because I have recently completed my full analysis of absorption and I wanted to compare my results to the warmist views. While this article is not about my results, it will focus on some interesting results that I found using their models. Because I was searching for the warmist views about energy I was using information from their sites (and citations of course). While that might seem strange, they generally have lots of good information there.
The starting point is the basic equation they use to determine the forcing caused by a change in CO2 concentration.
CO2 Forcing Equation
This equation provides the amount of energy in W/m2 that a difference in two CO2 concentrations should cause.
While looking for the total forcing of CO2 in the atmosphere, I found an interesting article on the Skeptical Science (SkS) site that had an answer to my question (citation). They state that the radiative flux caused by CO2 is 32 W/m2. I will use the information from that article several times. When I compare the energy calculated by the forcing equation using CO2 levels of 1 ppm and 390 ppm I get a result of 31.9 W/m2. So far things are looking consistent for the theory of AGW. Here is a chart of the forcing from 1 ppm to over 1000 ppm.
Proposed Model of CO2 Forcing
The next step is to determine how much warming this energy causes. For this I use the next important equation that the AGW model uses. That is the climate sensitivity.
Climate Sensitivity: Warming caused by Forcing
Again I found lots of discussion and references at the SkS website (Hansen et al. 2006) where they provide their views about climate sensitivity. This equation is straightforward and simple to decipher. They generally calculate it by looking at a period of time with a temperature change and then estimate the change in forcing. For example if increasing CO2 caused a forcing of 2 W/m2 and the observed temperature change was 5 °C, then the climate sensitivity would simply be 2.5 °C /(W/m2).
One thing to be aware of is that the sensitivity is usually not shown directly. Most warmist publications display the results in terms of temperature change that will happen as a result of forcing. For example the most commonly used quantity for climate sensitivity is 3.0 °C for a doubling of CO2. To determine the climate sensitivity they are using it is simply:
λ = (3°C / 3.7 W/m2 ) = 0.81 °C/(W/m2)
I am going to use the direct climate sensitivity instead of the temperature effect that a forcing will cause. This will make my numbers look a little different, but here is the conversion.
Proposed Range of Climate Sensitivity
When comparing climate sensitivity it is very important to know exactly which form is being used. I will be using the actual climate sensitivity instead of the CO2 doubling form. The best way to check is to look at the units being used.
The most common estimate is the 0.81 °C/(W/m2). That is what corresponds to the 3 °C temperature increase for a doubling of CO2. The full range is what I have shown in the table. Some estimates do go a little higher or lower, but the 0.43-1.13 °C/(W/m2) is the most widely accepted range.
SkS puts the climate sensitivity at the 0.81-0.92 °C/(W/m2). I am going to use the 0.81 °C/(W/m2) as the default value for the warmists as it is the most commonly used value.
So far all of this seems perfectly reasonable and hopefully acceptable. This is also where the wheels start to come off.
I decided to look at another method to determine the climate sensitivity. I am troubled by the method normally used because it is very hard to know the exact forcing and cause of the temperature change. So I decided to use what should be a less controversial method, but somehow I doubt it works out that way.
I decided to use the total Greenhouse Effect (as the ΔT) and then the energies involved. The total Greenhouse Effect is perhaps the least controversial aspect of the Global Warming debate. I will use the normally accepted value of the Greenhouse Effect as 30 °C.
Now by using the climate sensitivity value it is possible to compare what portions of the Greenhouse Effect (GHE) are caused by different components. Since the accepted forcing value for CO2 is accepted as 32 W/m2 it is now possible to determine the total impact that CO2 has on the total GHE.
ΔT = (0.81°C/(W/m2)) * 32 (W/m2) = 25.9 °C
While that might not immediately seem unreasonable. The entire stated effect of the GHE is 30 °C. So according to the accepted climate sensitivity and CO2 forcing equations, CO2 accounts for 86% of the total GHE.
So all other factors in the Earth’s climate account for 14% of the GHE and CO2 by itself accounts for the other 86%. This can also be compared to the number of CO2 doublings that take place from 1 ppm to 390 ppm. That is roughly 8.6 CO2 doublings (1,2,4,8,16,32,64,128,256,390 ppm). Using 8.6 doublings from 1 ppm gives 25.8 °C. So their model is coherent, but saying that CO2 causes 86% of the GHE is extremely incorrect.
This means that the methods being used for determining temperature change based on forcing and climate sensitivity are flawed. Any result that puts CO2 at 86% of the GHE is wrong. Earlier I showed that the forcing model and the accepted total forcing have a good match. That would indicate that the problem is with (at least partially) the estimated climate sensitivity.
So I worked backwards. Assuming that the total temperature change caused by the GHE is 30 °C and then the total energy inputs are the total forcing. The total GHE is not very controversial. Very few people will argue that the Earth is not warmer as a result of the atmosphere. Without the atmosphere the Earth would be around -15 °C and with the atmosphere it is currently about 15 °C. That 30 °C difference is caused by the insulative effect caused by the atmosphere.
That leaves forcing as the problem in determining the correct climate sensitivity. The same article that stated CO2 as 32 W/m2 also stated that water vapor causes a forcing of 75 W/m2. If I assume that water vapor and CO2 are the ONLY factors I get a total forcing of 107 W/m2. This would indicate:
λ(30%) = (30°C /107W/m2) = 0.28 °C/(W/m2)
Already using very poor assumptions the climate sensitivity is already much lower (by almost 3x) than the accepted value. This still puts CO2 at 30% of the total GHE, so even this estimate for climate sensitivity is still too high.
The normally discussed range of CO2 effect on the GHE is 9-26%. Assuming that the 32 W/m2 remains accurate for the forcing magnitude of CO2 results in climate sensitivities of:
λ (9%) = (30°C / 356 W/m2 ) = 0.08 °C / (W/m2 )
λ (26%) = (30°C / 123 W/m2 ) = 0.24 °C / (W/m2 )
At 9% of the GHE the climate sensitivity must be 10x lower than what is currently accepted. There is one more possible scenario that I want to cover.
If I look at the Radiation Budget (Kiehl, Trenberth 1997) I get a total forcing from the surface to the atmosphere of 452 W/m2. That would include the energy from evaporation, convection and radiative transfer and subtracting out the open window of 40 W/m2. If I use the 32 W/m2 for CO2 with that total energy then CO2 accounts for 7% of the total GHE. Then the climate sensitivity is:
λ (total energy) = (30°C / 452 W/m2 ) = 0.066 °C / (W/m2 )
That is what the real lower limit of the climate sensitivity is. The flaw in the estimates for climate sensitivity is the assumption that all temperature change is caused by the greenhouse gas forcing. If the climate was as sensitive as the much higher estimates currently in use are, the Earth would be a very unstable place as small changes in energy would cause large changes in temperature.
Using the total GHE determined climate sensitivities, here are the CO2 doubling effects on the climate.
GHE Determined Climate Sensitivities
What this shows is that trying to determine the climate sensitivity from a change in measured temperature and then assuming it was caused by a particular forcing is incompatible from the determination of climate sensitivity from the actual GHE. In choosing between methods it is the GHE that is a known quantity. Since the measurements have been done to determine the individual parts of the GHE, that seems to be a much more reliable method than “assuming” that a particular forcing caused a certain change in temperature.
The IPCC and the general AGW method of determining climate sensitivity is about an order of magnitude different than the method of using the total GHE and then calculating the components. This is a significant scientific disparity.
The difference the climate sensitivity makes to the temperature projections based on increasing CO2 concentrations are significant. Assuming the same CO2 forcing while using the different climate sensitivity values results in the following effects of CO2 on the global temperatures.
Red: The AGW accepted climate sensitivity of 0.81 (3C for doubling) Green: Climate sensitivity of 0.28 (1C for doubling) Blue: Climate sensitivity of 0.066 (0.24C for doubling)
The total GHE of 30 °C is incompatible with the currently accepted IPCC values of climate sensitivity and CO2 forcing. In order for the GHE to be compatible, the total effect of the greenhouse would have to be closer to 100 °C which would result in a global temperature of ~85 °C. This strong overstatement of the climate sensitivity substantially weakens the idea that CO2 could cause measurable change in the Earth’s climate, much less the type of danger that is often being stated.
This does not mean that CO2 is not a significant portion of the Earth’s greenhouse, but it does limit the role that it plays in the total GHE. The climate sensitivity is what prevents the sum of the parts from being greater than the whole and the sum of the parts cannot be greater than the total observed GHE. If the current estimates of CO2 forcing and climate sensitivity do not fit within the parameters of the total GHE effect, those estimates must be incorrect.
John Kehr
Sorry about being skeptical on your calculations, but I need you to consider this:
At first using the alamist numbers you attributed 86% of the GHE on CO2 forcing. But that is excactly what they say – they say clouds and water wapor are only feedbacks which are dominated by CO2. So what your calculations mean is that if their assumptions about CO2 as the driver and water wapor as the engine are correct, the climate sensitivity estimates are also correct.
Or am I missing something here?
Thanks John,
Very interesting post, simple and clear!
Doug Proctor says:
October 25, 2010 at 8:24 am
The place where distrust and acrimony will live is in the literate but non-professional arenas such as WUWT. We need to find some foe, if not friend, to sit at the table and engage in discussion.
Is there anyone out there or are we more victims of the two solitudes?
There is a small amount of interaction going on between my site and that of scientistofdoom regarding the (in)ability of ‘back radiation’ to warm the oceans at the moment. Dialogue is good, between people who regard each other as equals, at least intellectually.
Missing one big piece of information, where does the original forcing figure come from. From the global circulation models with no apparent justification other than trust us???
It might be instructive for people wondering how the greenhouse gas process affects the atmospheric Temperature to look at a simple case of another kind; and you can get an adequate picture of this from Wikipedia.
The somewhat similar case would be the relatively simple mechanism of the Helium Neon Laser. Everybody knows that the He-Ne laser emits a red line at 632.8 nm; which results from an electron transition of the Neon atom. Well actually it can also emit a nice infrared line at 3.39 microns and another one at 1.15 microns, both of which are Neon emissions. Well these days you can also get a green He-Ne laser.
So what the hell is the Helium for. Wiki shows how this all works. To get the Neon to lase; you have to “invert the population” of electrons in certain states of the Neon atom; and the ones you play with determine which wavelength is emitted. The actual wavelength selection is done with spectrally selective mirros on the cavity mirrors; that are high reflectance for the chosen line; but poor reflectors for the wavelengths you don’t want; but that has nothing to do with the Helium.
The electric discharge in the tube is basically a discharge in ionised Helium; which requires lower energies than NEON. So you end up with Helium ions which are in some higher energy states, and they are above the energy levels that you want to populate in the Neon atom system. So this is akin to the way CO2 can absorb a photon in the 15 micron range and excite the bending mode of the CO2 molecule.
The Helium excited ions, NOW COLLIDE with neon atoms; and energy is conveyed to the Neon atom via a phonon transition which is a mechanical quantum of energy ( heat), and that phonon reaction is what transports the original electric energy to an excited inverted population of neon atoms. So that is directly analagous to the transfer of energy from the CO2 molecule (or other GHG) to the ordinary N2, O2, or Ar molecules of the atmoshpere; those too are analagous to phonon transitions; where momentum is exchanged along with energy; but no Photon is involved. This energy conveyance via phonons, results in warming the atmosphere; there really isn’t photon transport from the CO2 to the N2/O2/Ar.
Once the atmospheric gases are warmed to a higher Temperature by this energy shift from the GHG to the atmospheric gases; then the normal black body like thermal radiation of infrared Photons can take place from the atmosphere to give the downward (and upward) LWIR thermal radiation from the atmosphere; which depends only on the atmospheric Temperature.
In the lower density and cooler ionosphere, as Phil has pointed out, the mean free path between molecular collisions is now long enough that the original excited GHG molecules can and do spontaneously decay, with the emission of a photon that is characteristic of the GHG energy level structure; and not black body like dependent on the Temperature; well it will have a Doppler line broadening that depends on the square root of the Temperature (K).
And as far as I know the thermal EM radiation is explained pretty much completely in classical Maxwell’s equation electromagnetic wave theory; due to the acceleration of electric charges which in turn is a consequence of the Temperature; and the momentum changes that occur during collisions. The only quantum aspect that needs to be added is what Planck did; which was to simply insist that each mode of oscillation had only a quantized energy (multiple of kT); whereas the earlier Raleigh Jeans derivation assumed that the oscillator energy could be any continuous value; and that led to the so-called Ultra-Violet catastrophe that predicted very high spectral radiance at ever shorter wavelengths.
But Planck’s little change fixed the whole problem, in one of the crown jewels of modern Physics (BB radiation theory); and in a way largely started the whole quantum ball rolling. But the derivation of BB spectra involves NO atomic or molecular electron energy level structures; only that the energy assigned to each degree of freedom be an integer multiple of kT.
So look at the Wiki He-Ne explanation, and it will give you an idea of how a not unlkike process works in the GHG picture.
Enjoy !
“Teh solar spectrum contains about 45% of its total energy beyond 750 microns, and only 1% beyond 4 microns; so there is 44% of the total solar energy in that range; and water vapor bands might actually acount for about half of that. Which is why the extra-terrestrial TSI of 1366 W/m^2 gets attenuated to a clear sky air mass one level of about 1,000 W/m^2.”
Point well, taken. I did underestimate the total amount of energy in sunlight in the IR band — even though the intensity is low, the tail is rather broad and includes a good chunk of the energy in the solar spectrum. I also underestimated the amount of IR absorption by water in the near IR. So rather than a ~2% of the energy getting absorbed on the way in by H2O as I suggested, the number is actually closer to ~20%.
I don’t think that changes my overall conclusions, though.
For one thing, that IR energy is STILL absorbed by the atmosphere, not reflected as clouds do for visible light. Hence it still gets added to the heating of the earth as a whole (albeit in the atmosphere, rather than on the surface).
Or put another way, the atmosphere is blocking ~67 W/m^2 of IR (that ~20% you mentioned) that fails to reach the surface due to absorption by various GHG’s along the way. But GHG’s add extra ~342 W/m^2 of downward IR to the earth’s surface. Get rid of H2O (and CO2 and CH4 …) and you add back that 67 W/m^2 — but you lose the 324 W/m^2!
Or simply consider that the blackbody temperature of the earth (without atmosphere) in equilibrium with the sun is WAY colder than the observed temperature. As stated in this very blog: “Without the atmosphere the Earth would be around -15 °C “. Dave Springer claimed in his comment that the moon is around -35 °C. Either way, the temperature of the earth with no atmosphere would be WAY colder than it is.
The only way for the earth’s surface to be warmer than that is for other radiation to be reaching it. (OK, there is a tiny bit of geothermal energy working up to the surface, but the estimates I have seen for that are around 0.1 W/m^2 so that really don’t matter. Or warm air could be warming the earth by conduction, but that seems too absurd to contemplate since the vast majority of the atmosphere is COLDER than the surface — the overwhelming consensus is that the atmosphere COOLS the surface thru convection.)
So where is this radiation coming from if not the atmosphere? And where in the atmosphere is it coming from if not the major greenhouse gas, H2O?
I can’t see any way to escape the logic that more water vapor (and more GHG’s in general) should and do have a net affect of warming the planet.
(Again, other feedback certainly affects the system — like perhaps more water vapor –> more water droplets –> more clouds –> higher albedo –> cooling. But that is a different and more complex topic than I think we are discussing.)
George E Smith
Thank you for your contributions. This has been my thought on this subject for a while now. Though, I would certainly be less eloquent in my presentation. That is, based on the observed data climate sensitivity is neither linear nor continuous. In fact, there is no guarantee that even if we can know the climate sensitivity at a given time and place that it is repeatable.
PS: Are you THE George E Smith, Nobel Laureate in Physics?
Doug;
It is one of the burdens of my existence that since late 2009, I have had to issue disclaimers to the effect that I AM NOT The George E. Smith who was last year’s Nobel Prize winner in Physics; but I know of him although I have never personally met him. He was at Bell Labs; where he did his Charge Coupled device (CCD) research; while I was VP of R&D for what was at one tme the largest LED company in the world (which we started from a kitehcn table). Every time I went to an industry conference, I would find I was already registered; but it was the Bell Labs chap.. It turns out that the diretor of R&D for Beckman Instruments at that time was also a George E. Smith;I’ve not met him either.
Then there was a George Smith who was a 19 year old sailor on the Battleship Oklahoma during the attack on Pearl Harbor; and that was the ship that rolled over and trapped a lot of sailors underwater. They eventually saved a great many of them by cutting holes in the hull of the ship which took several days.
George Smith dived off the deck as it was rolling over, and narrowly missed getting squished by the superstructure as it came down. He swam ashore to Ford Island with very few others, under a sea of burning fuel oil through which he had to periodically surfaced, and got horribly burned; but he survived and I think is still alive today; and he has an Oklahoma survivors web site. Check it out; it’s an inspirationalk story.
I can’t claim any achievement that matches that.
HankHenry says: October 25, 2010 at 3:55 pm
Tim Folkerts “(Kinda like rocks deeper down are much hotter,
but that doesn’t affect the IR radiation either.)”
It would be nice if you could expand on that sentence. I have things figured differently. The presence of heat in rocks deeper down and coming upward from internal heat sources makes the cold pool of the deep ocean more worthy of consideration.
I actually hadn’t given it a lot of though, but here is my understanding after musing a little while.
Overall, there is about 0.1 W/m^2 of geothermal energy working its way up (at least from estimates I have seen — for example http://en.wikipedia.org/wiki/Geothermal_gradient). This is a pretty small number on most scales associated with global temperatures.
In the absence of any other heat sources or sinks, there will be a gradual warming the farther down you go. Themal energy moves only upward via conduction in solid rock of the crust — deep mines are always warmer than the surface.
However, the temperatures in the deep ocean are governed primarily by convection. Ice cold water from near the poles sinks and is carried along the bottom of the oceans. This apparently is a much bigger heat sink than the average 0.1 W/m^2 heat source of geothermal energy coming up from the bottom (I haven’t done the calculations, but it seems entirely plausible). Hence the geothermal energy cannot warm the water much and it remains icy cold.
(Of course, the this is just a side point of a side point — the more important point was that neither the hot rock a mile down nor the cold water a mile down affects the IR radiation from the surface.)
John Kehr says:
So according to the accepted climate sensitivity and CO2 forcing equations, CO2 accounts for 86% of the total GHE.
And yet, over at Skeptical Science where you lifted the radiative flux figure of 32W/m2 for CO2 from, in the very same sentence:
The greenhouse effect or radiative flux for water is around 75 W/m2 while carbon dioxide contributes 32 W/m2 (Kiehl 1997).
it attributes a value of 75 W/m2 for water vapour. So… when the portion of the GHE attributed to water vapour is obviously over 2x that of CO2, how the heck can CO2 account for 86% of the GHE?
There are numerous other outrageous howlers in your ‘analysis’ (Ian H already pointed out that the logarithmic equation you are using for CO2 forcing completely breaks down for small values of starting CO2), but they will have to wait till tomorrow as it’s getting late here.
Should we add some climate sensitivity feedback math to the discussion?
The Clausius-Clayperion equations say that specific humidity increases 7% for each 1.0C in temperature.
– CO2/GHGs doubling causes +3.7 Watts/m2 extra forcing which increases the tropopause temperature by 1.0C and the surface temperature by 0.68C so humidity levels should increase 7% at the tropopause and 4.5% at the surface.
– Given the last GISS study, we can take 75% X 150 Watts/m2 X 4.5% (water vapour feedback based on its percentage of the greenhouse effect) and we get +5.0 Watts/m2 from water vapour feedback.
Calculations from the same Clausius-Clayperion equation says that cloud cover should increase by about 2% for each 1.0C. Increased cloudiness by 2% will change the Solar forcing by about -0.4 watts/m2.
There will also be some Ice Albedo feedbacks but the temperatures have to rise by a big enough number to make alot of difference in these numbers (it is already a low number since the majority of the Ice is above 75N). Given some of the numbers from below, I would estimate a reduction in Albedo of 0.004 (I have a model for Albedo and have played around with it enough to say this is probably close) which would result in an increased Solar forcing of +1.0 Watts/m2.
So, we have GHG forcing and the feedbacks for the Surface of:
= +3.7 Watts/m2 CO2/GHG forcing;
= +5.0 Watts/m2 water vapour feedback;
= -0.4 Watts/m2 increased cloud feedback; and,
= +1.0 Watts/m2 reduced Ice Albedo feedback.
= +9.3 Watts/m2 = +1.6C per doubling.
I have ended up at about this same number using four different methods now.
I made a little mistkae in the above at 6:10 pm, the 2% increase in cloudiness should result in -1.0 watts/m2.
So, we have GHG forcing and the feedbacks for the Surface of:
= +3.7 Watts/m2 CO2/GHG forcing;
= +5.0 Watts/m2 water vapour feedback;
= -1.0 Watts/m2 increased cloud feedback; and,
= +1.0 Watts/m2 reduced Ice Albedo feedback.
= +8.7 Watts/m2 = +1.5C per doubling.
“Ensemble reconstruction constraints on the global carbon cycle sensitivity to climate”
http://www.nature.com/nature/journal/v463/n7280/full/nature08769.html
“Amplification of Global Warming by Carbon-Cycle Feedback Significantly Less Than Thought, Study Suggests”
http://www.sciencedaily.com/releases/2010/01/100127134721.htm
Mike Borgelt says:
October 25, 2010 at 2:37 pm
wayne says:
October 25, 2010 at 1:45 pm
Wayne, I think Vince very firmly has his tongue in his cheek there.
Well I’ll put Vince on my ‘know’ list, thanks. Just didn’t recog the name and couldn’t let that influence someone not in the scientifically know, thinking this article was all wrong. (That’s my usual approach only because there are thousands just reading and not that familiar with the people and the lingo and, yeah, hidden sarcasm. Vince, that was good! Fooled me. )
@ur momisugly Tim Folkerts: Got that, thanks. And he is right, over long periods that is basically the correct mean temperature of this climate system to use smoothing out weather and the decades. I see now whereDave was coming from.
John,
To understand just how complex this analysis can get, see this post by Chris Colose. As was pointed out to you at your blog, your analysis was dangerously simplistic.
“”””” Tim Folkerts says:
October 25, 2010 at 5:15 pm
………………………………
Or simply consider that the blackbody temperature of the earth (without atmosphere) in equilibrium with the sun is WAY colder than the observed temperature. As stated in this very blog: “Without the atmosphere the Earth would be around -15 °C “. Dave Springer claimed in his comment that the moon is around -35 °C. Either way, the temperature of the earth with no atmosphere would be WAY colder than it is. “””””
Well sorry to disappoint Tim; but that simply is not correct. Wthout the atmosphere; there are no clouds, and no O2/O3/H2O/Co2 absorption of of incoming sunlight so the ground level solar insolation would be 1366 W/m^2, rather than 1000 W/m^2. and the equilibrium black body Temperature would become 275.7 K instead of 255K
That is 2.5 deg C above freezing rather than -18 deg C and that is quite without any greenhouse effect whatsoever. There would be no snow deposited on either the mountains, or the antarctic continent, or the arctic ocean ice, and the reflectance of aged ice is way less than fresh snow; so you can count on the albedo contribution of the polar regions going down from its present low level; and that will further increase the result of the increased solar input; because even more of it would be absorbed by th earth than with the present amount of ice albedo which is small compared to the cloud albedo.
Laci and Scmidt seem to forget the clouds are the major part of earth’s albedo, and they ignored the fact that the 255 K BB equilibrium Temperature at earth orbit, is caluclated assuming that 0.3 total albedo which goes away if water disappears from the atmosphere, and certainly if there is no atmosphere. The total physical, and chemical properties of H2O in all its phases along with some biological effects, is the controlling factor of earth’s comfort Temperature range.
I could calculate how much it could actually change with CO2 if I had those joker’s supercomputer and a model that didn’t start with declaring H2O to be simply a positive feedback amplification of CO2 as well as clouds.
As it turns out, over at c-r just a few weeks back, Peter Humbug stated that he had in fact removed ALL of the H2O from the atmospehre on his play station; and he got it all back in just three months. that doesn’t support the laci conclusion that water would collapse irreversibly .
The paper by Wentz et al demonstrates that the temperature H2O relationship is a very large negative feedback stabilizing effect.
Interestingly; Bill Illis just posted somewheres hereabouts that Clausius-Clapeyron predicts a 7% increase in specific humidity for a one deg C surface Temperature rise. Interestingly Wentz et al found from satellite measurements that a one deg C rise results in 7% increase in evaporation, precipitation and total atmospheric water. I conjectured from that a similar increase in cloud cover to go along with the increased precipitation.
In contrast, the GCMs (according to Wentz) agreed with the 7% increase in total water; but said evap/precip (which must match) only increased by 1-3 %. That is as much as a seven x difference between actual measured real world data, and the computer models which can’t seem to get water modelling including clouds correct.
I’ve asked Lacis to explain; but so far no response; that happens a lot; I post something which just drops into a black hole.
richard telford says: October 25, 2010 at 7:51 am
There was a similar post to this on WUNT a month or two back. Not surprisingly they share the same flaw.
This seems to be similar to describing the starter motor is the most important part of an automobile. Without it the car is just a hunk of expensive metal.
There is a long chain of events going back 4.5 billion years that gives us our atmosphere and its characteristics today. Since the planet had a CO2, N2 atmosphere before photosynthesis in plant life changed it to the O2, N2 version we have today. Past ice stages of the planets history happened in spite of the remaining CO2 in the atmosphere.
Sure, there may be a “tipping point” where if CO2 and other persistent green house gasses reach a low enough level that atmospheric moisture may be lost to surface ice and an new Ice Age begun. However, that is for low levels of CO2. The point in contention is what happens when persistent green house gasses increase from today’s levels.
Once our automobile engine is running, the starter motor is just along for the ride.
George E Smith;
I just had a rant on another thread about the same issues. Well not exactly the same. Your included all the math anda few more points. Couple to add.
1. There’s not such thing as radiative forcing from CO2. Its like centrifigul force. Everyone uses the term, but it doesn’t exist. Centripetal force exists, and CO2 in theory resists the escape of energy to space. There’s no 3.7 watts/m2 being “forced” into the system at the top of the atmopshere. CO2 is distributed throughout the atmosphere, and an upward bound photon can be absorbed and re-emitted in a random direction, some of which is back toward earth, at any altitude. So the RESISTANCE to earth’s radiance escaping to space is distributed from surface to TOA. No force outward on a body travelling in a circle and no forcing at TOA.
2. For those jumping all over water vapour being a positive feedback, read George’s retorts on the matter, they are well founded, but add this thought experiment. At sea surface at 15 C, water vapour is 30,000 ppm or so. As you climb in altitude, it gets colder, and cold air can’t hold as much water vapour, so the concentration falls off the higher you go. Imaging a slice of atmosphere really thick with water vapour at the bottom, but really thin at the top. Now imagine CO2. Its spread pretty much evenly from top to bottom at a teeny tiny 280 ppm. POOF is suddenly doubles. What happens? Well some of those upward bound photons that made it past the water vapour at the bottom and used to escape to space clunck right into them, get absorbed, and some get re-emitted back toward earth. About 3.7 w/m2 worth of them. Now here’s the important part. They don’t start from the TOA. Some of them get absorbed and re-emitted a millimeter above the surface, and some at a meter and some at 500 meters and so on. So now there’s 3.7 w/m2 more downward photons than there were before, their “source” being spread out across the entire range of altitudes where CO2 exists. Now here’s the other important part. The earth starts to warm up, meaning more water vapour, mostly at low altitudes where most of the water vapour is in first place. Does it absorb and re-emitt upward bound photons from the earth’s surface, thus increasing the RESISTANCE to photons leaving the planet? Why yes it does. But those darn water vapour molecules don’t actually know up from down and neither do the photons. So, since most of the CO2 is distributed ABOVE most of the water vapour, some of the photons that CO2 sent back to earth wind up hitting all that water vapour instead which absorbs and re-emitts it in a random direction, sending some of it back upward. Ooops, negative feedback. Wait! All that extra water vapour doesn’t just absorb and re-emmit photons sent back down by CO2, it does the same to photons sent back down from Ozone, Methane, clouds and anything else in the atmosphere that tries to send some of the photons back. So more water vapour is a negative feedback to ALL the GHG RESISTORS.
That being the case, seems to me the concept of water vapour being nothing but a positive feedback has been torpedoed by the randomness of photon emissions. This may have practical use some day for building photon torpedoes, but that’s WAY in the future when we’ve stopped being so sensitive about climate.
Tim Folkerts
“Of course, the this is just a side point of a side point”
Not sure I agree with you. If water in polar seas cools at the surface (presumably by radiating heat into the black of space) and then sinks, isn’t that an IR heat loss that is then represented in the cold waters of the deep.
I imagine the earth as an internally warmed body which is cooled at the surface by the dark of space. In other words a body with a temperature profile that goes from high temps at the center to cool at the surface. It strikes me as odd that while that is the profile for continents the profile for oceans must be something like …. rising temps to the ocean floor then a significant temperature drop at the depths of the ocean and then a re-rise of temps at the surface. It makes me believe that the earth creates huge amounts of arctic temp. seawater at the poles that it then slips underneath the ocean surface at all latitudes. The fact that continental rock at oceanic depths is quite hot just makes me think that this deep ocean cold is even more significant part of what should constitute the Earth’s “average” surface temperature. … remembering that the heat storage capacity of water in its liquid state has a much greater heat capacity than air.
I still don’t understand why you can’t use one spot on the globe as a reference point, and sort out the sensitivity from there. Use the difference in forcing from the sun between day and night. Why does this not work? It must not, or it would have been done already. Unless it falls in that range of things that are too simple, like looking for the car keys that are in your hand already. But I doubt that. Why wouldn’t this work if you used averages? That is what climate science is all about, after all.
One point that really bugs me about virtually every paper, post and comment I have ever seen on climate sensitivity and/or the earth’s energy budget is that everyone assumes that these issues can be satisfactorily explored on the basis of a static model. It is assumed that day and night, variations in TOA insolation due to the earth’s elliptical orbit, seasonal changes due to the inclination of the earth’s axis , and variations in the energy budget due to geographical location ,can all be averaged out without any impact on the analysis. Nowhere have I ever seen any proof that this assumption is valid, or even a reasonable approximation.
Excellent again. Even if this wouldn’t be a scientific paper in itself, it would most certainly make a good critical reply to one, and one they would most likely have to tackle…
Jeff L says: October 25, 2010 at 11:56 am
“I would love see a warmist post on here an analysis of why this is not a correct analysis.”
Hi Jeff. The analysis is flawed. Please refer to “Tim Folkerts says: October 25, 2010 at 1:34 pm” for a simple exposition as to why.
George E. Smith says: October 25, 2010 at 8:40 pm
Well sorry to disappoint Tim … the equilibrium black body Temperature would become 275.7 K instead of 255K.
Actually, you don’t disappoint at all! Quite the contrary, you provided some great info to think about.
I should amend my statement to be “As stated in this very blog: “Without the atmosphere the Earth would be around -15 °C “. Dave Springer claimed in his comment that the moon is around -35 °C. George claimed the temperature would be as high as +2.5 C. In any of these cases, the temperature of the earth with no atmosphere would be WAY colder than it is. ”
I was trying to avoid dealing with specific temperatures, because the estimates do indeed vary. A big part of that is because it is difficult to do the thought experiment “remove all the atmosphere with other things being equal”. 🙂
What ever assumptions you make about the surface of the earth in that scenario make a huge difference in the final result. I was trying to avoid that whole issue by simply going with “much colder” because that much seems to be pretty much certain.
One other detail that would seem important is the emissivity as a function of wavelength. Unless I am badly mistaken (which has been known to happen), if the earth has high emissivity for visible light, but low emissivity for IR (ie it absorbs visible light from the sun well, but emits its own IR poorly) then the temperature would end up ABOVE the pure BB temperature. Conversely, if the earth has low emissivity for visible light, but high emissivity for IR then the temperature would be BELOW the pure BB temperature. If the emissivity was the same for all wavelengths, then the temperature would be at the BB temperature.
From a quick look around the web, the second scenario (below BB temp) seems to fit data I saw, but I am certainly no expert on IR spectroscopy.