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
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This is a question akin to the one: “what happens when you double the insulation thickness of double glazing”. In theory, the insulation is proportional to the thickness of air, but the reality is that air doesn’t just sit there and do what the “theory” says.
Just as air in double glazing will start to flow in a convective cycle, so the atmosphere churns in a convective cycle tearing the static model of the atmosphere apart and making it useless to determine the impact of CO2.
CO2 is not only a warming gas, the same physical properties make it a cooling gas where the CO2 is warmer than a heat sink like outer space. It helps radiate IR from the convective cooling cycle into space, and the higher the level of CO2 the more effective the cooling cycle. QED too much CO2 will cause atmospheric cooling
The truth is that the impact of CO2 is not anything like as simple as the above article suggests, and the only way to determine what its affect is, is to measure it’s real impact on the atmosphere and not the theoretical impact.
I find this post very hard to follow, particularly the use of Modtran. But this:
“thus when changing concentrations of CO2 we get total atmosphere responses incl feedbacks if present”
seems to be the basis of it, and is wrong. Modtran just works out the IR radiative balance of an atmosphere of prescribed concentration of gases. It does not account for feedbacks, which vary the concentration, of water vapor particularly, in response to warming.
The problem is that you start with a model for forcings in Watts per square metre where you say that each doubling is equivalent to 10.8% of the total forcing – fair enough. But you then use this result to derive sensitivity in K. I don’t see how the two follow. You can’t infer anything about sensitivity, which is a temperature, from forcings, without including all the feedbacks.
Hence the need to manufacture warming by playing surfacestation twister, cherrypicking data, and factoring in ‘adjustments’.
It’s not happening, the predicted warming.
What is happening is the wilder side of climate is showing itself once again.
Inquiring younger generations speak with older generations that remember what it was like.
Now you have multiple generations figuring it out for themselves.
It’s not happening, the predicted warming.
Excellent post and points made by Mike Haseler above.
But the science no longer matters. CO2 falsehoods are now an entrenched and growing part of the global economy driven by political beneficiaries. CO2 and consequently global warming is a deliberate false economy, much like toxic mortgages are part of the present financial implosion.
The Co2 swindle is now a legitimate growth business opportunity for most economies, the science is completely irrelevant.
“…I wonder if the peoble creating the 350 ppm demonstrations knows this?
I wonder how they will react when they find out…”
In the same way that any other loony greenie groups react when facts are put to them – they’ll press on regardless and wave their placards harder and shout their message with even more fury. They’re not interested in reality…
(You only have to watch some of the video clips where Chris Monckton engages with some of the demonstrators at Copenhagen, to realise this).
This is brilliant. I always wondered what would happen if all the doublings were hindcasted, what would they show, but was too lazy to figure out how to get the information needed to show it. This does that perfectly.
0.6K per doubling passes the smell test. To the best of my knowledge, Lindzen & Choi showed about that even in their revised calculations using actual observations. It also ties in with Chip Knappenburgers analysis as to what would be the effect if we reduced all of our emissions by 80%.
The question now is when will this become a peer reviewed paper so that the IPCC will have to include it in their next report.
Mike Haseler writes: “The truth is that the impact of CO2 is not anything like as simple as the above article suggests”
Agreed. However, the concept that CO2-effect is similar for each doubling is not exactly my idea 🙂
MODTRAN shows this relation (that off course originates from the logarithmich declining effect of CO2) so MODTRAN is “too simple” and many other too.
Mike, if you say that for example the doubling 80ppm to 160ppm does NOT have near the same effect as the doubling 160ppm to 320ppm – (?) please argue for this. Then many scientists has got it wrong.
I do not think that everything i illustrate above is 100% accurate, obviously. I just pinpoint how bad the building blocks of the CO2 hypothesis used today actually fit together.
And the “fact” that greenhouse gasses in the first place should account for the ALL of the 33K insulating effect of the atmosphere is not proven and definetely not likely at all. So when i use the 33K I actually overestimate the effect of greenhouse gasses and thus CO2.
But, Mike Considder this:
How do you think Hansens claim of 6 K warming effect of ONE CO2 doubling match the MAX 33K effect of ALL greenhouse gasses combined?
K.R. Frank
This theory is all very well but why, in the geological past when atmospheric CO2 concentrations were 3000ppmv plus, did we not get past the so called climate tipping point and into runaway global warming. None of the so called greenhouse effect is supported by geological history. There is also the serious problem of the violation of the laws of thermodynamics which is being ignored by many so called skeptic scientists. There cannot be a theory that violates these physical laws. There is also the ice core problem. It has been shown that in the geological past temperature rises are FOLLOWED by parallel rises in CO2 levels. Temperature cannot be driven by atmospheric CO2 levels.
The other greenhouse gases refers primarily to water the concentration of which depends on temperature. So, divide 30 by 10 (or nine if you like) and you get 3C per doubling 😉
Hansen’s 6K is for a strange definition of climate sensitivity including slow feedbacks, ie the icesheets albedo.
For runaway warming you need to consider that we only have poor proxies of past CO2 levels, let alone other forcings, and we know that the sun should have been less bright in the past.
”
Vince Causey says:
September 8, 2010 at 12:54 am
The problem is that you start with a model for forcings in Watts per square metre where you say that each doubling is equivalent to 10.8% of the total forcing – fair enough. But you then use this result to derive sensitivity in K.
”
Hi Vince!
Change in W/M2 is generally accepted to be proportional to Change in temperature (K). I think Shaviv got around 2,2 W/m2, and others around 3,7 W/m2.
But this is not the point at all you are digging in 🙂
The point is, that doublings of CO2 is widely accepted to have the same warming effect (no matter if we use W/m2 or K).
This gives a problem when for example Hansen says that ONE Co2 doubling shold cause 6 K warming…
MODTRAN shows that what ever warming ONE doubling has, the total Co2 warms around 9,25 times as much. in this case 55 K
Even if there is not 9,25 “doublings” in the total CO2 warming effect, lets say just 6 “doublings”, then Hansens value demands that COs shold be related (feedbacks or not) to more warming than all greenhouse gasses combined 🙂
Please try to see what im saying. Its the number of doublings and the claims of the warming effect of each doubling… no matter if we use unit W/m2 or K.
K.R. Frank
You’ve started way too high! Start with one molecule of CO2. Double it until you get to a single mole. Already – even if we assume CO2 is responsible for 100% of the 33k warming – a half degree per doubling is too high!
I tried starting with zero molecules of CO2, but it kept getting hotter and hotter with no increase of CO2 (it’s worse than we thought!). How’s that supposed to work?
Best,
Frank
Mike Haseler says:
September 8, 2010 at 12:35 am
Just as air in double glazing will start to flow in a convective cycle, so the atmosphere churns in a convective cycle tearing the static model of the atmosphere apart and making it useless to determine the impact of CO2.
Are you saying the tropopause doesn’t exist?
”
Heiko Gerhauser says:
September 8, 2010 at 2:01 am
The other greenhouse gases refers primarily to water the concentration of which depends on temperature. So, divide 30 by 10 (or nine if you like) and you get 3C per doubling 😉
”
Njaaaaah 🙂
We live on a globe with 70% water surface. Today there is around 100 times more water in the atmosphere than CO2. This means that the wavelenght for water are saturated mostly, so variation in warming effect from water is tiny tiny tiny.
So, an atmopshere without CO2 will not affect H2O greenhouse effect much.
So your equation:
” divide 30 by 10 (or nine if you like) and you get 3C per doubling ;-)”
demands that without Co2 there would be no more warming effect from water 🙂 I think you see the problem…
More: I calculated from all 6 scenarios used in my article above how much greenhouse effect there would be left without any CO2: 91,1 %
So according to MODTRAN, the total CO2 related warming is MAX 9% of the33 K – but still, to be conservative in my article i used the normally used 15%. So again i have overestimated the CO2 effet in my article to be able to defend it.
K.R. Frank
Good post.
Can you please clarify: The IPCC estimates include the other feedbacks, don’t they? Then the 6K is supposed to be a result of CO2 and added H2O. Does you model run include a static value for H2O in the athmosphere for the different CO2 concentrations?
Nitpick: The ppm scale in the graphs should stay logarithmic, now it is a bit misleading visually with the doubling switching to 350 and 390.
On a sidenote: Slap together warmer = wetter planet and a tipping point for a runaway temperature? I suppose we should be extremely worried about local scorching temps during rainstorms and overcast, maybe halestorms followed by giant fireballs are the future of AGW?
”
Frank Kotler says:
September 8, 2010 at 2:15 am
You’ve started way too high! Start with one molecule of CO2. Double it until you get to a single mole. Already – even if we assume CO2 is responsible for 100% of the 33k warming – a half degree per doubling is too high!
”
Agreed. my 0,54 K for CO2 sensitiviy demands that ALL insulating effect from the atmosphere is due to greenhouse gasses, and it demands that the CO2 related warming is 15% of total greenhouse effect – while MODTRAN actually says its only 9 %.
(Too say that an atmosphere without greenhousegasses shold not be insulating the planest at all it completely nonsense. ALL planets show atmosphere with similar insulating effect, even Saturn that has mostly just H2 and He2 and then trace amount of other substances…!!)
K.R. Frank
Empirical data trumps models every time. Frank Lansner has used a model to show that climate sensitivity to CO2 is less than IPCC predictions. Nick Stokes has correctly pointed out that this model does not factor in water vapour feedback. But what does the empirical evidence say? According to Dr. Lindzen and Dr. Spencer the feed back from water vapour is neutral to negative. The basis to their conclusions was empirical data from radiosondes and satellites.
Konrad says:
September 8, 2010 at 2:43 am
“.. this model does not factor in water vapour feedback. ”
No, please understand:
Each CO2 doubling has a warming effect just being a fraction of the total COw warming effect.
So
Each CO2 doubling warming effect WITH feedbacks are just a fraction of the total CO2 warming effect WITH feedbacks.
Each CO2 doubling warming effect WITHOUT feedbacks are just a fraction of the total CO2 warming effect WITHOUT feedbacks.
The fact that there are many CO2-doublings comprised in the total CO2 pool has NOTHING to do with MODTRAN and thus if MODTRAN uses feedbacks. Nick is just missing the core of this problem.
As basis for the discussion, ALL doublings have the same feedbacks , same warming effect – unless otherwise documented or at least suggested and explained.
Hansens 6 K per CO2 doubling includes feedback. But then its his idea that feedbacks did not work for the doublings 20-40ppm? 80-160ppm?
No, ALL Hansens CO2 doubling must lead to feedbacks (!) and therefore a total atmosphere insulating effect of 33K is NOT in compliance with or exmaple Hansens 6K doublings that includes feedback.
Just 5 of Hansens 6 K CO2 doubling including feedbacks equals the whole atmosphere warming! As though the 100 times more abundant H2O had almost no effect was it not for CO2. This is Absurd. Nick and all must see this is a problem.
K.R. Frank
The Climate sensitivity wiki article you refer to says…
As a non-scientist, I have always followed Lindzen that the dispute is about the feedback component of sensitivity. From the responses above (from folks that seem to know about this stuff) it seems that this post is only confusing the issue…and also….buying into this issue in this (non-empirical) way only encourages the scholastic aspects of this science.
Berniel, Your quote states that IPCC believes that each CO2 doubling incl feedbacks should lead to 3 K warming – just as I said in the article.
So for example 5 CO2 doubling (influding its feedback) should account for around 15 K. This is half the insulating effect of the atmosphere. So if we reduced CO2 by 5 doublings, the atmosphere should only insulate half as much as today? No something IS wrong.
Remember, that Water is by far the strongest greenhouse gas and is 100 times more abundant in the atmosphere than CO2 , and the CO2 effects including feedback appears significantly overestimated by the IPCC.
Each doubling of CO2 without feedbacks just adds a little heat to the atmosphere. Why should each doubling (= each adding of a little temperare from Co2) not lead to the same feedbacks?
No the doublings- unless documented – should have same effect including feedbacks, and therefore Each doubling cannot have these huge warming effects claimed by IPCC and Hansen. These estimates are just not in compliance with the MAX total atmosphere insulating effect.
I have used MODTRAN – but if I had used another model, i would not change, that there are many doublings of CO2 in the total Co2 amount – AND that each doubling incl feedback should lead to nearly the same warm effect. (Unless otherwise documented.)
K.R. Frank
Frank Lansner says:
September 8, 2010 at 2:12 am
”
Vince Causey says:
September 8, 2010 at 12:54 am
The problem is that you start with a model for forcings in Watts per square metre where you say that each doubling is equivalent to 10.8% of the total forcing – fair enough. But you then use this result to derive sensitivity in K.
”
Hi Vince!
Change in W/M2 is generally accepted to be proportional to Change in temperature (K). I think Shaviv got around 2,2 W/m2, and others around 3,7 W/m2.
We live in alternate realities for sure.
In my reality, change in Kelvin follows a black/gray body formula of
Energy flow= C*T^4
Delta(E)=C*4*T^3*delta(T)
Proportional NOT. And it is a matter of physics and measurements, not of consensus.
Frank Lansner says:
Mike Haseler writes: “The truth is that the impact of CO2 is not anything like as simple as the above article suggests”
Agreed. However, the concept that CO2-effect is similar for each doubling is not exactly my idea 🙂
Frank, the reason I was a bit pointed in my comment is that this static analysis of the atmosphere is the lynch pin of the warmist camp. Basically, their whole publicity campaign is based on a single STATIC passive heated model of the atmosphere.
The argument everyone knows is as follows:
1. Fossil fuels produce CO2
2. CO2 traps IR
3. Fossil fuels are warming the atmosphere.
4. Any warming/severe weather/changeable weather/plague of frogs is proof that we are burning too much fossil fuel.
This article is basically repeating this stupid train of logic that seems to compel us to believe CO2 has a simple single impact which is to warm the atmosphere as a GREENHOUSE …. at which point most people start imagining the world being as warm as a real greenhouse.
If we want to defeat global warmers, we have to stop trying to argue about the merits/demerits of a numpty static model of the atmosphere, and start showing that the atmosphere cannot by modelled by the Micky Mouse “science” of these numpties.
OR TO PUT IT ANOTHER WAY, THE DESTROY THE CO2=GREENHOUSE WARMING MESSAGE
That is why, whenever I am able, I mention the cooling effect of CO2 because this destroys this simple message – it is a simple way to introduce some complexity to the model and which totally undermines the apparently compelling argument of the static “co2 warms” model.
It has lovely symetry:
CO2 blocks IR => CO2 emits IR
Therefore:-
More CO2 warms => more CO2 cools.
Therefore:-
More CO2 causes warming => more CO2 causes cooling
For anyone who’s belief is based on badly learnt schoolboy science, as soon as you introduce some complexity and therefore uncertainty by the cooling effect of higher levels of CO2, the whole inevitable logic of global warming falls apart and becomes: “what is the relative cooling and warming impacts of CO2”.
As this can’t be answered by simple waving of the hand arguments, it totally demolishes the foundation of the “CO2=WARMING” message of the propagandists.
But, so long as (well intentioned) people keep engaging with the warmist agenda of “how much warming” does the “CO2 Warming gas” cause, which is the same as saying: “It is right to model the atmosphere as a static unmoving mass”, so long as people keep alive this static analysis of the atmosphere, we will never defeat this propaganda machine.
Just to restate the dynamic model of CO2 cooling:
Air heated at the surface rises by convective currents, and then is cooled by IR emission into space. The addition of CO2 to this warm air mass increases the rate of cooling thereby increasing the rate of cooling of the atmosphere.
“… the value range used by IPCC appears unlikely to physically impossible.”
Is this what you mean to say?