9,25 – a factor that could close the global warming debate
Guest post by Frank Lansner (hidethedecline)
The CO2-sensitivity describes the warming effect induced by a doubling of the CO2 concentration in the atmosphere, and is thus the epicentre of the global warming discussion. Estimates of the CO2 sensitivity are very different, and the value range used by IPCC appears unlikely to physically impossible. To show this, I will focus on the factor “Fw” between the total CO2 warming and then the warming from a single doubling of CO2 concentration.
The total CO2 warming effect is obviously many times bigger than the warming from a single CO2 doubling. Example: When changing CO2 concentration from 5 ppm to 320 ppm we have 6 doublings. But on top of these 6 doublings, how much warming effect is introduced when CO2 concentrations are changed from 0 to 5 ppm etc? In the following I use the online model MODTRAN:
Fig. 1. Above is illustrated the warming effect of CO2 for 3 different climatic areas. Zero W/M2 represents the net forcing of the atmosphere fore a given scenario with CO2 concentration set to 0 ppm.
For each area is shown a clear sky scenario as well as a light rain scenario. All other variables in MODTRAN are left as the default values. The results from MODTRAN are total atmosphere outgoing radiation, and thus when changing concentrations of CO2 we get total atmosphere responses incl feedbacks if present.
Fig 1 Shows 6 doublings of CO2 concentration: 5-10-20-40-80-160-320 ppm where every doubling shows warming effect of similar size (–as could be expected due to the logarithmic declining effect of adding more CO2 to the atmosphere).
From the graph above we can see that the total CO2 warming effect today equals around 9 times the warming effect of one doubling of CO2 concentration.
Fig 2. For a better compare between the scenarios on fig1, these are now shown as %-values of the total CO2 warming effect for (Forcing) with today’s concentration of 390 ppm CO2, equals 100%. It appears that clear sky, rainy sky, Arctic area, tropics, subtropics scenarios has a very similar profile indeed and I find that this result shows that we can consider these %-trends to be rather global.
Fig 3. The average global CO2-doubling can now be calculated more accurate to be near 10,8% of the full CO2 warming effect at 390 ppm. (Or, the “CO2-sensitivity” warming effect is around 10,8% of the total CO2 warming effect, globally.)
Thus, the “best estimate” of the factor between total CO2 warming effect and the warming effect from one CO2 doubling – Fw – can be calculated. Best estimate (so far) Fw = 9,25.
CO2-warming-total (K) = 9,25 * CO2-warming-from-one-doubling (K) = 9,25 * CO2 sensitivity (K)
I have used MODTRAN for this result, but it is universal that the doublings must have near same warming effect and thus the individual doubling will have just some fraction of the total value. For now, the factor 9,25 is best estimate.
Hansen – CO2 sensitivity.
Now how does the factor 9,25 between total CO2 warming effect and CO2 warming effect from a single doubling support the viewpoints of James Hansen on CO2 sensitivity?
James Hansen often refers to a CO2-sensitivity of 6 K… 6 K warming effect for each single CO2 doubling:
Fig 4 James Hansens CO2 sensitivity of 6 K gives around 55,5 K of total CO2 effect using the factor Fw = 9,25. As the total warming effect of all greenhouse gasses is assumed to have a warming effect of approx 33 K, the Hansen CO2-sensitivity demands that the total CO2 related warming effect is bigger than all the greenhouse gasses effect combined.
The overall CO2 warming effect is supposed to be around 10-15-2% of the total warming effect of the atmosphere, here we use 15%. Since CO2 is assumed to account for 15% of the total 33K greenhouse effect on Earth, the CO2 total warming effect is around 5 K. So just ONE CO2 doubling of Hansen’s CO2 sensitivity of 6 K has a bigger warming effect than the total warming effect supposed to be possible.
It is therefore highly odd that Hansen’s claim of 6 K CO2 sensitivity has been taken seriously anywhere at any time.
Here the “greenhouse wheel” (see WUWT post Wheel! – – Of! – – Silly!) where supposedly scientists imagine that we by year 2100 can have warming of over 7 K in fact with less than one CO2 doubling to cause this:
Fig 5. To account for their 7 K temperature increase, they must have played with a CO2-sensitivity of perhaps 10 K? So these honourable “scientists” believes that one CO2-doubling might resemble a third of the combined earth greenhouse effect?
IPCC – CO2 sensitivity
Then, how does the factor 9,25 between total CO2 warming effect and CO2 warming effect from a single doubling support the viewpoints of IPCC on CO2 sensitivity?
IPCC AR4 viewpoints for the CO2 sensitivity :
http://en.wikipedia.org/wiki/Climate_sensitivity
IPCC “best estimate” of warming from one CO2 doubling is 3 K.
Using the Fw = 9,25 we learn, that if one doubling warms 3 Km then the total CO2 warming should be around 28 K ( = 9,25 * 3 )
We must then remember again that the total warming effect of the atmosphere is generally accepted to be near 33 K. The warming effect related to CO2 should then be around 85% of the total Earth atmosphere greenhouse gas effect. And without CO2, the atmospheres warming effect should be reduced to 15% of todays atmosphere…. On a globe with mostly water-ocean surface…
The IPCC numbers where each doubling of CO2 represents 3 K it simply does not fit at all with the total warming effect of the atmosphere.
IPCC then claimed:
“Values substantially higher than 4.5°C cannot be excluded..”
Well, 4,5 K for CO2 sensitivity gives a total CO2 effect of 41,6 K. This is 126% of the total earth greenhouse effect, so we could rephrase:
IPCC:
“Values of CO2 related warming substantially higher than 126% of the total greenhouse gas warming cannot be excluded..” …
Idso´s and Lindzens estimates for CO2 sensitivity.
What if we assume that CO2 is responsible for the 15% of the 33K greenhouse warming effect on Earth? This corresponds to 5 K. If true, the CO2 warming from one doubling should be
CO2 sensitivity = CO2warming-total / Fw
CO2 sensitivity = 5K / 9,25 = 0,54 K
So just using the generally accepted knowledge that CO2 sholuld account for around 15% of the total Earth greenhouse effect, and using the also generally accepted knowledge that total Earth greenhouse effect is 33K, then the CO2 sensitivity should be near 0,54K
Idso 1998 suggests 0,4 K, and Lindzen suggests 0,5 K these results appears sound and realistic in strong contrast to values from IPCC and Hansen.
Hansens 350 ppm ”safe level”
Fig 6. When working with CO2 – effect, one cant help wondering what Hansens ”safe level” of 350 ppm CO2 is all about.
Fig 7. NASA´s, James Hansen has claimed 350 ppm to be a safe level of CO2:
– Just 1,5 % less Warming effect from CO2 and we are “safe”.. ?
If CO2 has a total warming effect of 5 K – as previously calculated – the difference between the Hansen “safe level” CO2 warming and todays level is around 0,075 K.
I wonder if the peoble creating the 350 ppm demonstrations knows this?
I wonder how they will react when they find out.
Idso 1998:
http://www.int-res.com/articles/cr/10/c010p069.pdf
MODTRAN:
http://geoflop.uchicago.edu/forecast/docs/Projects/modtran.orig.html
Go up on Mt. Tam early in the morning and watch S.F. emerge from the fog any nice day.
Visualize where all that moisture goes. And what goes up must come down.
Commit random act of observation on thermodynamic beauty.
Ron Broberg (see above) has a nice exposition on Frank’s work.
And he links to this
http://geotest.tamu.edu/userfiles/88/greenhouse_effect.pdf
Sorry Gnomish, i’ve seen no math from you that explains or predicts anything. When you have some math that actually works, when you can actually make a prediction, then you are saying something that is testable. And we can test that math by asking what it predicts for global temperatures following a large volcano, for example. Until then, you don’t have a theory to test.
Zeke: So, what I have shown is perhaps mostly, that the warming effect from the present doubling HAS to be much much greater than for any other doubling. And I think thats a relevant point, because such a claim has to be supported directly like “The present CO2 doubling will warm the earth many times mores than other CO2 doublings because…”.
And as i wrote in my previous comment, all the earlier interglacials shows that a little warming mini-peak of 0,5-1 K has never resulted in a 6K (or 3 K for IPCC) temperature rise before.
K.R. Frank
Frank Lansner says:
September 8, 2010 at 2:14 pm
Is this to some degree explaining why the upper atmosphere has been cooling for decades?
Frank, I simply don’t know and I don’t want to blindly speculate outside of physics. Do you see a tie there?
Did learn something new while thinking on you question, at http://www.nsstc.uah.edu/data/msu/t4/tlsglhmam_5.1, Dr. Christy and Spencer’s site, that shows those upper atmosphere temps have basically been level since 1995, didn’t realize there was such a one time step 1995, interesting.
Mr. Mosher, I’m happy to remember you for your achievements.
Let it rest with that, please. There is no upside.
Wayne, well its an interesting thought:
More CO2 => Radiation absorbed a bit lower in altitude =>
A slight cooling effect of upper atmophere layers =>
Less water in upper atmophere layers =>
Less greenhouse effect in upper atmosphere layers =>
Again (!!) A slight cooling of upper atmosphere layers =>
Less water… … ..
So – just thinking loud – a CO2 increase should perhaps lead to a significant cooling of upper atmosphere.
Well, its pretty much the pattern from the observations, its the upper layers that loose water quite significant as CO2 increase:
http://hidethedecline.eu/media/feedback/e5.jpg
K.R. Frank
Frank,
sorry, but your chart is crap. You changed from logarithmic to linear at 320 without apparent reason. I stopped reading there.
Rabe… So because YOU thought it was something else, then its CRAP?
I needed to highlight the values for the doublings, and I needed to show 350 ppm too for the compare. If this makes you loose the ability to interpret data, thats really not my problem.
Steven Mosher says:
September 8, 2010 at 8:46 pm
Thanks Steven, I will chew that over for a while. I have had a little experience with wing panel design, my bit was taking the design through to manufacture, always understood that all models were based on wind tunnel observations. But I suppose they have to start somewhere.
Thanks for getting back.
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Chris Knight says:
September 8, 2010 at 11:47 am
I would guess that NASA does not think that observation of the earth’s albedo is important….
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There is the Earthshine project: http://www.hindawi.com/journals/aa/2010/963650.html
“…..The earthshine observations reveal a large decadal variability in the Earth’s reflectance [7], which is yet not fully understood, but which is in line with other satellite and ground-based global radiation data….”
Working this idea backwards, if we assume (as the IPCC seems to) that sensitivity is essentially constant (ie one doubling always is +3K) then we can use this “fact” to produce a sensitivity from known widely accepted values.
The following figures are all taken from RealClimate.
http://www.realclimate.org/index.php/archives/2005/04/water-vapour-feedback-or-forcing/
Total Atmospheric Warming from GHGs is 33K
High figure for CO2 portion of that warming is 34% of that or about 11K
Low figure for CO2 portion of that warming is 9% of that or about 3K
Somewhat conservatively and starting at 6ppm there are 6 doublings of CO2 to get to our present levels, 6->12->24->48->96->192->384
Therefore the high estimate of sensitivity is 11/6 = 1.8K
And the low estimate of sensitivity is 3/6 = 0.5K
Let’s also note that doubling CO2 is calculated to increase the forcing in the troposphere by 3.7 W/m2.
With feedbacks and lapse rate considerations, the surface forcing is predicted to increase by 16.5 W/m2 if surface temperatures are supposed to increase by 3.0C.
+3.7 W/m2 Troposphere ——-> feedbacks ——-> +16.5 W/m2 Surface
Little known fact it seems.
Gavin Schmidt and the gang at GISS have a new paper in press which breaks-down the greenhouse effect into its various sources:
Water vapour – 50%
Clouds – 25%
CO2 – 20%
Others – 5%
(these numbers do not take into account the solar reflection or atmospheric interception of solar energy by the same gases but it is what it is – just long-wave radiation – and clouds should be the same as water vapour but nonetheless).
http://pubs.giss.nasa.gov/docs/notyet/inpress_Schmidt_et_al.pdf
Frank Lansner says:
September 8, 2010 at 11:59 am
General comment:
MODTRAN suggests that a CO2 doubling has 10,8% the effect of the full CO2 amount. That is, MODTRAN shows that CO2 has a total effect 9,25 times greater than a single doubling.
Feedbacks: There appears – so far – to be no specific reason why feedbacks like water evaporation etc should be more strong in connection with the 160-320 doubling than the 20-40 doubling or any other doubling…..
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From my point of view the IPCC has it donkey backwards because they always ignores the long term evidence. They insist CO2 influences H2O as the cause and effect feedback when it is water that is the critical chemical in governing the climate not CO2.
CO2 is more soluble in cold water then in hot. The oceans warm due to increase in solar energy from the Milankovitch cycle.
“Solar energy reached a summer maximum (9% higher than at present) ca 11 ka ago and has been decreasing since then, primarily in response to the precession of the equinoxes. The extra energy elevated early Holocene summer temperatures throughout the Arctic 1-3° C above 20th century averages..” Source
As the oceans absorb more energy from the sun (down to 100 meters), temperature increases and CO2 is released from the oceans giving the 800yr lag seen in the Ice Core measurements. When the temperatures reach a certain point, above 35C or 95F, the daily afternoon thunderstorm cooling cycle kicks in moderating the temperature increase.
During glaciation water is again a critical factor in the form of ice/snow albedo.
I think to switch from Interglacial to glacial you need the correct point in the Milankovitch cycle, a grand solar minimum, cold ocean cycles with major volcanic action acting as the trigger. We know one major eruption can cause a few years of deep cold, that is a year “without a summer.” The effects of Laki’s eight-month eruption in 1783 causing major disruption to weather patterns is an example of what I mean. If the snow does not melt in the summer you then have the ice/snow albedo kick in and at the correct point in the Milankovitch cycle, solar cycle and cold ocean cycles there just isn’t enough energy to keep the glaciers from growing.
Water, solar energy, and volcanoes make sense as the major climate drivers. 350ppm of CO2 is just a bit player.
Study of Dust in Ice Cores Shows Volcanic Eruptions Interfere with the Effect of Sunspots on Global Climate
“The research, published in a paper in the May 15 [2002] issue of Geophysical Research Letters, provides striking evidence that sunspots — blemishes on the sun’s surface indicating strong solar activity — do influence global climate change, but that explosive volcanic eruptions on Earth can completely reverse those influences.
It is the first time that volcanic eruptions have been identified as the atmospheric event responsible for the sudden and baffling reversals that scientists have seen in correlations between sunspots and climate…
“By carefully studying the timing of other volcanic eruptions, we found that they coincided with all of the correlation reversals between sunspots and climate,” said Ram.
A chart in the paper shows how six major volcanic eruptions between 1800 and 1962 occurred during precisely the same years when there were reversals in the correlation between sunspot activity and climate….
The UB team discovered that these additional sulfates cause cosmic rays to have a more pronounced effect on Earth by spurring the formation of small droplets in the atmosphere that, in turn, cause the formation of a type of cloud that does not produce rain.
“During these times of high volcanic activity, the sunspot/climate correlation reverses and dust levels rise, even in the absence of high sunspots,” explained Stolz. “
Steven Mosher (Sept. 8, 2010 @ur momisugly 8:13pm)
A couple of questions for you. How does one model a hot source in the sky? Please enlighten me. Details please.
Since when is MODTRAN required to build a jet fighter? At what point do the calculations become important to the final design. Sky mentioned its also good for remote sensing, in what way?
Also do you have any references to modtran back in the early seventies or sixties?
Frank, it’s “lose” not “loose”. Since you’ve done it multiple times, I’m guessing it’s not a typo.
Your pants get loose when you lose weight.
Gnomish<
"Go up on Mt. Tam early in the morning and watch S.F. emerge from the fog any nice day.
Visualize where all that moisture goes. "
why visualize something we can measure. Take a look at the stratosphere. Think a bit and get back when you realize that the energy that gets to us from the sun through the moistureless vacuum of space, returns to space the way it came.
Steven Mosher says: September 9, 2010 at 7:42 am
> Take a look at the stratosphere.
Well that would be good, except I cannot find a consistent and coherent description of what is at and is supposed to be happening above say 10Km – and it’s not for the want of trying. Where do you suggest we look and why only the stratosphere?
It leaves me with the destinct impression that all this conjecture is just that, supposition and guesswork. Not a sensible basis for declaring that CO2 is causing problematic warming over a time period which seems to be getting shorter and shorter as time goes by.
“Brian W says:
September 9, 2010 at 7:00 am (Edit)
Steven Mosher (Sept. 8, 2010 @ur momisugly 8:13pm)
“A couple of questions for you. How does one model a hot source in the sky? Please enlighten me. Details please.”
Well, you can do it as a point source or as a 3D object. As a 3D object it may emit differently depending on your view angle or the orientation of the object. Take a look at the picture of the YF-23. You see that “deck” on the aft end of the plane? That deck had heat ablating tiles. Actually for the prototype we used shuttle tiles. From below you only see two type of heat signature. You see the wavelengths given off by “hot metal” and you see the wavelengths give off by aeroheating. If the plane were to roll over and fly upside down ( or if you view it from above) you would see the signature of hot gases. So, you build a three dimensional object with 3 different emission characteristics that depend up the material it is made of, how fast it is going, and what the power setting of the engine is. The same thing is done for RCS for example. In that case the shape is much more complex. Those shapes are all predicted shapes based on models of how radiation ( from a radar) interact with surfaces made of particular materials. Long ago ( like when the F117 was built) we could only predict the returns from flat surfaces and we could only built flat surfaces ( of RAm material). later, on the B2, Northrop had a break through in predicting the returns from curved surfaces, namely guassian surfaces. So the designers got to use those kinds of surfaces. The models of the aircraft surface had to be precise down to ( cant say) mm because of what happens when you get even a tiny crack in the surface.
“Since when is MODTRAN required to build a jet fighter? ”
Since the airforce started demanding it ( they hold some of the patents on it ) as part of the proof of concept. (At the start I think we used lowtran, but there were improvements needed.) Basically, to build an aircraft it works like this. The airforce will write a SRD. a systems requirement document. They will specify, for example, that the aircraft “shall have” an IR signature of a certain level, or alternatively they may say that the aircraft shall be undetectable to a ground based IR sensor. So, they give us data on the ground sensors and their sensitivity and their location and they ask us to prove with models that the plane we propose to build is survivable in that enviroment. They give us approved models to use. we run the models. they run the models and check out our predictions. It might go like this: The airforce demands that we be able to penetrate an airspace at, say, 25K feet. We would run the model, say MODTRAN, and modtran would tell us that what the plane at 25K feet would “look like” to an observer on the ground. ( if you look at MODTRAn you will see that you can be looking up or looking down) But at 25K feet there may be planes above you looking down. they see something different. So you may come back to the air force and say “25K feet” doesnt work. Its an iterative design/specification process that took a decade at least.
“At what point do the calculations become important to the final design. ”
Well, the calculations are used throughout the design process. from proof of concept ( a drawing with a bunch of models to back it up) through PAV ( prototype air vehicle) all the way to production. Even after production if I wanted to propose a change to the vehicle I would probably have to run the model. Want to change the engine? How’s that impact survivability? You’d typically have to prove ( using models) that the change would improve ( or not diminish) the survivability. How do you do that? you run a model, a survivability model. That model runs the aircraft through a designed mission and outputs a probability of survival. And you would simulate, and estimate what would happen to its survivability against other airbourne threats ( IR missiles). Want to change a fuel line? you might have to re run a shot line analysis in which you simulated bullets being fired at the plane ( I think that was COVART, but I never did that stuff) heck with the F-18 we had to supply 5 planes to be shot up to calibrate the models. Fun stuff.
“Sky mentioned its also good for remote sensing, in what way?”
well any sensor in the sky or space needs to understand what the atmosphere does to the signal. If you emit signal X at the ground hows that get modulated by the stuff between the sensor and the source. Going backwards, if you recieve a signal that looks like Y, what does the source actually look like? for space bourne sensors to operate you have to understand what C02 does to radiation as the radiation passes up through the atmosphere. Clouds in the way? clear sky? ice? aerosols, as the atmosphere changes the image you see can change. To keep track of all the changes there is a huge database called HITRAN. as we put new molecules in the atmosphere, then those modelcules get added to HITRAN. then the transfer codes ( like MODTRAN) use that database.
“Also do you have any references to modtran back in the early seventies or sixties?”
No, it was formalized in the mid to latter part of the 80s as an extension to LOWTRAN ( I think lowtran7 but its been a while) Lowtran stuff started in the mid seventies ( as I recall) which was before my watch. in the 70s, the drive to incorporate all aspect broadband stealth became paramount. hence the F117, B2, F22. Make sense? The airforce required stealth, so we had to design for stealth. before you spent a billion or so to build a prototype you better have good modelling that tells you just how invisisble the thing will be once it is built. You have to rely on modelling, calibrate the models, improve the models, test the models, field test your vehicle once it is built. So, modelling is at the core of the design. Heck we even had to simulate missions and wars. Fun stuff.
Gnomish says:
September 8, 2010 at 11:45 pm
Or late in the day when the fog rolls in again! It is truly an awesome sight (as well as being significant).
here Brian;
lib.semi.ac.cn:8080/tsh/dzzy/wsqk/SPIE/vol4719/4719-15.pdf
you can see how MODTRAN is used on the JSF
A nice history of source.. and you can see all the contributors to IR signature ( like glint which I forgot about, and earthshine etc );
dspace.library.iitb.ac.in/jspui/bitstream/10054/613/1/5740.pdf.
Anymore questions? google is your friend
Green Sand:
i won’t pretend to understand everything the flight control guys did, but it was first and foremost a modelling process. So for example to design a pitch controller, the gut would work with a database of aero forces. He would design a controller filled with all sorts of magical numbers called gains. Then he would run the model and look at the response of the aircraft, trying to get something that wouldnt pitch up too abruptly or over shoot to much and he would fiddle with the gain numbers until he got a system that had a response that looked like it met HQ specifications. and then at some point this model would be flown in an different aircraft hmm using this company
http://www.calspan.com/aerospace/flightControl.php
So, ya, had to do lots of modelling. you could not just design a plane and DERIVE the settings for HQ from first principle physics.
I didn’t want to remember the (heroic) person who broke climategate this way, but you insisted. So much for courtesy, then.
Get back when you figure out you can’t measure heat in degrees.
Get back after your refresher in first year chemistry.
Get back when you figure out the latent heat moved by water in any unit of atmosphere is 50,000 times greater than C02.
Get back when you can focus on a point without pages of resume as diversion.
Get back when you’re not so patronizing and give up the ‘argument from intimidation’
Get back when you become a mature adult, in other words.
I didn’t want to remember you like this, friend.
Let me tell you one of the secrets of life: when you’re really stoked about something- everybody wants to hang out with you. When you have a bad attitude and act stupid- nobody does. Celebrity is so fickle – and google is so indelible.
Top of the day to ya. I just finished putting new shingles on my roof and that will fix all my climate issues for another 10 years or so. I’m smilin. 🙂
Interesting concept, but I see a problem that could be a fundamental flaw.
When someone says the correct value for climate sensitivity should be ~3 deg C / doubled CO2, that includes the modeled net impact of all forcings and feedbacks. C02 forcing alone only gives ~1.2 deg C for doubling.
The extra ~1.8 deg C is a function of other interactions, mostly complex, and the magnitude may be different under other atmospheric concentrations and climactic conditions.
Treating that 3 deg C as a constant, and extrapolating it over all other doublings, especially at concentration levels which haven’t been experienced or modeled, is a likely to lead to erroneous conclusions.