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, John, JOHN!
Don’t you know you are just an “engineer”, and you just don’t have the finese, the “intellectual horse power” to handle these things? In point of fact, engineers should NEVER go out of their domain…(Think of that disasterous Frank Capra, Hollywood producer: Chemical Engineer, or Neville Shute Norway, Novelist: Metallurgist..whoops, I guess that’s a bad set of examples, they were succesful in both fields.)
Or imagine an untrained person, but bright and “on the job learning” type
doing good science (Micheal Faraday?)
Or a composer doing Chemistry? (Camielle Saint Seans?)
Shame on you for having the chutzpa to THINK that you could “compete” with the likes of Hanson or Pachurri! (Wait, wasn’t Hansen originally in phyics, and Pachurri a RAILROAD engineer?)
Well, you’ll figure out the errors of your ways eventually. No pressure, really!
I am just wondering if John Kerr could refer to the following research by atmospheric physicist, Dr Ferenc M. Miskolczi, and make further comment. Miskolczi’s published research is located at:
http://www.met.hu/idojaras/IDOJARAS_vol111_No1_01.pdf
Also, see the following link:
http://www.examiner.com/seminole-county-environmental-news-in-orlando/new-research-into-greenhouse-effect-challenges-theory-of-man-made-global-warming
Thank you.
There was a similar post to this on WUNT a month or two back. Not surprisingly they share the same flaw.
The greenhouse effect of 30C is for a planet with an albedo of 0.3. The earth would not be cooler by more than 30C if the atmosphere was not radiatively active because the albedo would increase because of increased snow and ice cover. You can see this effect in Lacis et al. 2010 http://www.sciencemag.org/cgi/content/short/330/6002/356
This is amazing work, assuming that their science is coherent, this makes sense to me in “the real world” in that CO2 might have a small effect (including forcing value), but its not the thermastat so to speak. This would also seem to correspond to other views on how CO2 does most of its work in the first couple of doublings so to speak.
I applaud the science, this might help us when we try to understand the climate better.
A minor editorial note: Thanks for including the boxes with conversions between two ways of expressing sensitivity.
It would be helpful to add a third line with the other common method of describing sensistity — watts/meter-squared/degree K.
That line would just be the reciprocal of your °C / (W/m2 )
This makes sense. The rate of warming looks to be out by an order of magnitude. If the climate was highly sensitive to CO2 forcing, the observed temperature now would be much higher. Hansen’s original model put the anomoly over 1C by 2010. Put simply this model has failed. It has failed because of this fatal climate sensitivity flaw.
“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. ”
Or, there is a strong negative cloud feedback not included in the models to date?
Caution, I’m a climate dummy. Please forgive if the question is dumb.
The whole concept of a climate senstivity which is independent of temperature seems a little strange to me.
Stable systems tend to become less sensitve to an input as they get pulled from the mean. The faster a car goes the more energy it takes to get a little bit faster. Models which suggest that an input which increases into the future will continue indefinitely and would never cause an increase in the negative feedback don’t seem particularly plausible to me. The more energy a system has, the faster it tends to leak away, and relying on a computer model – even if it accurately predicted the current situation – does not demonstrate its ability to predict an environment that has never been experienced.
Definitely a post to keep hold of
Thanks John
So much of the CAGW dispute is conducted within ideological camps that both errors and bias in approach are extremely difficult to determine regardless of one’s position. Is there a “reasonable” pro-AGW site that could become part of a dialogue instead of the other side of two monologues, and review these reviews?
There will never be a sense of peace or harmony in the climate change dispute if serious dialogue does not develop in the blogosphere. The academic disputes are insulated within their towers and, well, academic. Both sides receive professional and personal support for their positions even if later these positions change. 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?
Then there’s that pesky Vostok data hanging out there that shows atmospheric concentration of CO2 follows warming. How does the observed relationship between warmth and atmospheric concentration of CO2 square with the mathematical models? Should there not be a rigorous experiment to test the mathematical models?
Since there is substantial overlap in the absorption spectra of CO2 and H2O, you cannot simply add their contributions. The net absorption will be substantially less than the absorption of the individual components.
This is just one of many mathematical non-linearities in the climate system that are traps for the unwary (see Willis’ immediately preceding post for others). Most introductory classes in various types of systems analysis work pretty exclusively with linear systems, because they are easier to handle — it is very easy to forget this very strong assumption.
Thank you… VERY interesting and informative…
I wish I could say I was surprised or shocked… but I can’t… I’m simply lost for words… May the Intergovernmental Panel of Climate Charlatans rest in peace… while we try to remain respectful by not dancing on their computer simulated graves.
I believe the models would consider water vapor a feedback instead of a forcing.
Abit off topic but i just saw a news thread on FOX news that said that NOAA had just opened a new center with a new super computer that they claim will be able to make better weather and CLIMATE predictions than ever before. They claim it will be able to make yearly and decadel predictions like never before, Like the METUK computer that seems to make wrong predictions it will probrably make just as bad of a job of it.
The real issue will be if our “sensitivity” will endure the chilling cold ahead. It has been demonstrated here in WUWT, “ad nauseaum”, all that issue of Global Warming/Cimate Change/Climate Disruption, was a scam aimed at making business from pouring the empty into the void: buying “carbon credits” to third world countries at a peanuts’ price and selling “carbon shares” to “polluters” at a thousand times prize. The businesmen in between thus would happily profit. But, it happened in November 2009 what was called the “Climate Gate” and the rest is history…..
All characters in this, at the beginning, horror movie on a terrible armageddon to happen to earth and the humand kind, have turned into characters of a Travesty Comedy, really painful to bear .
It’s over buddy!
Quote: “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.”
This shows exactly what is wrong with the GCM’s and AGW-theory, because as far as I know H2O accounts for 85%-95% of the greenhouse effect.
Now, why not rework all those numbers but treat the oceans as part of the atmosphere for solar energy retention purposes ?
Thanks Mr. Kehr for a very logical and well-written article. This is a new and powerful argument in my arsenal against the AGW fraud.
“extremely incorrect…..”
now take me for a simple geologist but you can be either wholly correct or wholly incorrect, there are no degrees of correctness (unless you’re a geophysicist)
“An engineer is asked, what is 2 +2 , Engineer replies 4
A climatologist is asked what is 2+2, climatologist replies, 5
A geophysicist is asked, what is 2+2, geophysicist replies, what would you like it to be?!
boom boom crash.
Curt says:
October 25, 2010 at 8:28 am
I had to read this twice, and I do not think this is translating into “this linear model is correct”. I call it a model simply to make it easier to look at.
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:
Normally I would agree with you, but this is just a simple start to figuring out the actual sensitivity. 9-26% does not translate into a linear relationship to me per se. The 9-26% agreed upon I would believe translates into the overlap so to speak, which is why we have disagreement on the actual contribution of CO2. More then likely, even though its not going to be linear, the contribution of CO2 can be measured to “estimated guesses” by statistical methods. This is where you start good science in my mind to fine-tune it even better. I doubt it will come out linearly at all in the end, but it might be possible to estimate with a straight line so to speak.
There is a wide range of error obviously, but this is where I would think you would start to estimate the actual climate sensitivity. Right now, the methods uses are terrible by climate scientists and have not matched reality at all. This particular method could be tested unlike those models which are just meant to scare.
Look John, there’s no place for common sense or full-circle thinking in climate science o.k? Keep re-working your equations until you get the desired outcome (Sarc-off).
When they discuss the warming from a doubling of CO2 with a sensitivity of 3 degrees for that doubling, they include the amount of warming from the water vapor feedback in that calculation.
It doesn’t make any sense to then remove that feedback when discussing the contributions of water vapor and CO2 to the greenhouse effect.
After all, something has to provide the warmth to keep the water vapor in its gaseous state, and that something is CO2.
The warmer it is the less cloudy it is, or hasn’t anybody noticed that.
Very good demonstration. I find it incredible that scientists fixate on CO2 and ignore thermodynamics (adiabatic equilibria), evaporation/transpiration, meridional atmospheric circulation, clouds, solar interactions, etc., except that they have the idea that water vapor feedbacks will propitiate the very minor CO2 effect. Convection removes heat from the surface, otherwise we would be living in a Super Sahara world, even more terrible than the one envisioned by the warmers. We wouldn’t even be here.
Two items:
1. If you use the dF = 5.35 ln(C/Co) formula and take that input for Q = Cp*m*T over a one year time you will find as I did that there is “missing heat”.
2. I have pointed out several times on various blogs that the atmosphere exerts a large pressure on the earth. PV = nRT must be factored into the discussion. Under standard conditions (STP) this is 273 K or 0 C. So the maximum you need to account for in “GHE” is 15 C. Steve Goddard’s “Venus” post is an excellent example of why pressure matters.
Watts per meter squared mean nothing unless there is a frequency attached to it. My mircowave has more then 1000 W/m^2 but does not heat the air inside it, only the food. The base of a 50000 W transmitting tower should be the hottest place on earth, but it’s not.
CO2 is said to absorb at 2.3, 4.7 and 15 mirco. The 15 micro converts via Wien’s Law to about 200 K. If the surface is at 300 K CO2 will be uneffected.
The IPCC is wrong but for lots of reasons.