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
This is where “sensitivity” comes from:
http://davidgarnerconsulting.wordpress.com/2010/03/17/rothschild-cashes-in-by-investing-in-farmland/
Wanna increase your “feedback”and reach a “Tipping Point” ASAP?, just call old George.
Tim Clark:
Humidy drops and the greenhouse effect from H20 is reduced
This tells me you have never lived under a cloud cover which lasts more than six months.
It’s just the contrary: No Sol no warm. Common sense, ya know, the less common of all the senses.
Tenuc says: “…It is looking more and more like the total additional feedback mechanisms are negative rather than positive. Ice albedo has only a small effect during climate optimums as the distribution of the relatively small amount of ice is at the poles w(h)ere the angle of incidence (is) low, and even sea water reflects much of the incoming light at these latitudes….”
Right. You can see the effect of angle of incidence even at relatively high values. E.g., look out across the ocean from a hillside in late afternoon, and note how intense the reflection off the water is when the sun is still 30° above the horizon. Very little energy is being absorbed. The angle of incidence near the poles is always significantly lower than 30°, ranging between 23.5° and 0°. Any albedo feedback would be very small, possibly slightly negative at times, depending on ice age, particulate cover of the ice surface, clouds, wind velocity, and seawater plankton content, etc.
Tim Clark says:
September 8, 2010 at 9:57 am
“2nd graph = At ~350ppm [C02], the effect from CO2 is ~ 99% exhausted.”
May be practically true because each fixed increment of additional forcing requires doubling the CO2 concentration. I’m skeptical that there’s enough economically recoverable fossil fuel to get more than two doublings from pre-industrial level.
This indicates the earth has warmed ~all it will from 1st order CO2.
Since you are familiar with MODTRAN, and these numbers are correct disregarding 2nd order feedbacks, are you prepared to suggest that any temperature increase in the future as predicted by IPCC will be 99% associated with feedbacks (ie. somewhat synonomous with sensitivity)? If so, then explain why current global temps are lower than predicted by IPCC using a climate sensitivy of 3? (don’t weasel out on this – see previous post and IPCC graph of scenarios) Also, then are you suggesting that the hypothesized feedback effect is temperature dependent? At what temperature do the feedbacks suddenly appear? Should they not increase in a linear fashion?
Oops. In last to Tim Clark the last three paragraphs without quotes are his and should have been snipped as I only meant to respond to the first paragraph.
Tim Clark:
Humidy drops and the greenhouse effect from H20 is reduced
Enneagram says: September 8, 2010 at 10:54 am
This tells me you have never lived under a cloud cover which lasts more than six months.
It’s just the contrary: No Sol no warm. Common sense, ya know, the less common of all the senses.
Now reread what I wrote. I believe we agree.
Frank,
You wrote “James Hansen often refers to a CO2-sensitivity of 6 K… 6 K warming effect for each single CO2 doubling”. Hansen has argues for a high-end estimate of 6 K for equilibrium climate sensitivity associated with a doubling of CO2 from current levels, which takes into account various feedbacks (water vapor, cloud, albedo, vegetation, etc.) that do not necessarily operate equally for every doubling of CO2. He wouldn’t argue that -every- doubling of CO2 would have the same effect (apart from the feedback-free 1.1 C, and even that isn’t a linear at very small and very large concentrations).
Well I have no idea who or what MODTRAN is, but you have to start with the primary source of LWIR radiation (if the CO2 greenhouse effect is what you are studying; and that is the earth surface; which varies in Temperature over an extreme range of from 120 to 150 deg C from the coldest Antarctic midnight highlands; to the hottest midday tropical deserts; and over that range the surface emission varies by over an order of magnitude; from about double the 390 W/m^2 that Trenberth gives (corresponding to a 288 K Temperature, to about 1/6th of trenberth’s number for the coldest regions.
So how can a given amount of CO2 give some fixed “forcing” without reference to the Temperature of the terrain.
Also the “radiative forcing” does NOT vary linearly with the amount of Temperature increase it causes. The required forcing would be proportional to the 4th power of the resultant Temperature ; so you can’t have both the W/m^2 and the Temperature both change the same amount for any doubling.
And the very specification of a fixed Temperature increase per doubling; whether it be 1.5 deg C or 4.5 or even 6.0 automatically defines the Temperature to be a logarithmic function of the CO2; and the proxy data going back 600 million years and covering about 5 doublings; doesn’t show any evidence whatsoever for a logarithmic relationship between CO2 and Temperature. There are millions of years of absolutely constant Temperature while CO2 drops by huge amounts.
And for the modern era of actually measured values for CO2 and Temperature, the still isn’t 1/3rd of one doubling in the records and yest claims for the temperature effect range over more than a 3:1 ratio for a single doubling.
With a 3:1 range in the experimental estimates of the slope of this mythical logarithmic function; how can you possibly declear it to be logarithmic rather than linear. The data contains no respectable evidence for any mathematical relationship; other than both values are observed to change; and not always in the same direction or even the same direction as each other.
Climate Science is going to be forever stuck in the doldrums akin to ancient astrology, so long as practitioners keep on insisting ont eh existence of a mathematical relationship for which there is nore experimental evidence.
And you can’t salvage the claims by taking “feedbacks” into account; those “feedbacks” are themselves not constant throughout the system.
Either the mean global surface Temperature of the earth is proportional to the Logarithm of the atmospheric CO2 abundance or it isn’t; and so far, I have seen no evidence that it is; or is any other well defined mathematical function.
The available literature can’t even seem to agree among authors whether it is the global mean Temperature; or the w/m^2 “forcing” that follows the log of CO2 abundance.
Well it doesn’t much matter, because neither one does; based on the observational evidence. There isn’t even any agreement on what the proper time relationship is or should be, between observations of a mean temperature or a W/m^2 forcing , and the observation of a CO2 abundance; or even which direction that time relationship should point.
If the CO2 lags the Temperature by around 800 years, as the paleo proxy data suggests; why on earth would anybody be comparing the Temperature and the CO2 or the W/m^2 over the last 30 years or even the last 100 years; when there is no a priori reason to believe they are related in any simple way;as the paleo data shows.
AS for Hansen’s 6 deg C (not 6 K which is an absolute Temperature) per doubling; the last 600 million year paleo record shows that the re have been about 5 doublings^-1 over that 600 Megayrs; actually halvings of course from aroundd 7000 ppm down to around 220.
So that means that a 30 deg C total cooling must have accompanied that drop in CO2.
Instead we have a net cooling from 22 deg C down to 12 deg C or just a 10 deg change for five halvings.
So much for 6 deg C or even 6 deg F per doubling. total nonsense.
I would guess that NASA does not think that observation of the earth’s albedo is important. Any of the lunar landings could have had an instrument permanently measuring the sunlight or moonlight reflecting from the earth. SOHO could have had an earthward sensor too.
But, no the earth does not warm from sunlight, it warms from carbon dioxide that was meant to remain in the fossil layers of the earth’s geology. So be it.
Frank Lansner says (September 8, 2010 at 4:29 am): “Next article perhaps we should look at the other planets atmospheres, show that their insulating effect appears very unrelated to the particular gasses in the atmosphere…”
Steve Goddard covered Venus twice at WUWT and provoked over 900 total comments:
http://wattsupwiththat.com/2010/05/08/venus-envy/
http://wattsupwiththat.com/2010/05/06/hyperventilating-on-venus/
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.
If not, Lets take a NEUTRAL position, and assume that all warming feedbacks are mostly evenly sprespread out over the 9,25 “doublings”.
If so, the 6 K of CO2 warming inclusive feedbacks should pretty much equal the warming + feedbacks from all other doublings.
And with 9,25 this gives 55 K of warming effect in all related to CO2. This is around ten times the global temperature differences over the ice ages. I think its fair to mention this – and if anyone can explain, they are definetely welcome to do so.
K.R. Frank
Zeke, you write: “He [Hansen] wouldn’t argue that -every- doubling of CO2 would have the same effect ”
No… he would probably say that the present doubling has a much much higher effect than any other 🙂
But does he really have a sound basis to claim this?
Unless anything else is proven/shown convincingly, we must be assume evenly spread out feedbacks.
The CO2 effect is as you know just a minor temperature effect. Water will continously evaporate still more with higher temperatures. Its not like sudenly at a global average temperature at 15 degrees, the evaporation goes bananas and justifies a special boom in CO2 effect for the present doubling (!) even though it would be convenient for the AGW’ ers 🙂
K.R. Frank
K.R: Frank
– And therefore zeke, if Hansen claims 6 K incl feedbacks for this doublings, we must treat other doublings in the same way.
Or?
K.R. Frank
Frank,
Does absolute humidity (at a given relative humidity) change linearly with temperature?
And while we are on the subject of scientists and $$$
((Related News:Health Care · Science .
Swine Flu Found No More Severe Than Seasonal Virus
By Tom Randall – Sep 8, 2010 7:17 AM GMT+1000
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Business ExchangeTwitterDeliciousDiggFacebookLinkedInNewsvinePropellerYahoo! BuzzPrint Children infected in last year’s swine flu pandemic were no more likely to be hospitalized with complications or get pneumonia than those who catch seasonal strains, according to a study that challenges previous reports.
About 1.5 percent of children with the H1N1 swine flu strain were hospitalized within 30 days, compared with 3.7 percent of those sick with a seasonal strain of H1N1 and 3.1 percent with an H3N2 virus, researchers said today in the Journal of the American Medical Association. The report compared outcomes in Wisconsin of 545 patients with swine flu versus 853 patients with seasonal strains beginning in 2007.
Approximately 50 million people in the U.S. caught swine flu last year. Children were more likely to get sick than in a typical year, leading previous studies to conclude that the virus not only spread more easily but also was more severe. Today’s study was more in line with CDC estimates that about half as many people died of flu last year as in a typical year.
“The risk of most serious complications was not elevated in adults or children,” the study’s authors wrote. “Children were disproportionately affected by 2009 H1N1 infection, but the perceived severity of symptoms and risk of serious outcomes were not increased.”
Influenza is a rapidly evolving virus, and the severity of the season depends on which strains are circulating and how well a population has been inoculated. About 12,000 people of all ages died in the swine flu outbreak, according to the CDC. Annual deaths associated with seasonal flu ranged from 3,349 to 48,614 during the last 30 years.
Report Limitations
While today’s report was limited by its size and geographic reach, the study was large enough to show that swine flu wasn’t much more severe for kids, according to the researchers.
Comparing outcomes from different flu seasons is difficult, as survey methods vary. The Wisconsin study was set up to examine the same group of people during three flu seasons to reach a more precise comparison. Illness was assessed through interviews and flu tests. Patients’ medical records were reviewed to determine the severity of the illness and outcomes.
To contact the reporter on this story: Tom Randall in New York at trandall6@bloomberg.net. ))
Twas the same method. Identify a disastrous possibility that could not be morally challenged due to the affects on the young & the helpless. UN steps in as Co-ordinator General using the expertise of ‘scientists’. All repuiring $$$$$$$ by the train load. Doomsday talk of humanity disappearing, blah blah blah.
regards
Whoops. proof reader not here. ‘requiring’ was what it should have been.
regards
Zeke: Not 100% linearly but the evaporation as function of temperature is a smooth curve, no sudden jumps.
And by the way, if Hansen had a point with some special evaporation-boom these days, its just too bad that measurements of water in the atmosphere does not support him.
http://hidethedecline.eu/media/feedback/e5.jpg
K.R. Frank
Only one mention of (atmospheric) ‘window’ and Stefan – Kudos to Kilty …
Three or four mentions of ‘spectrum’ as well as ‘T to the x.x power’.
Of course, MODTRAN intrinsically should use those ‘factors’ …
.
Zeke: Here is a diagram of water phases as function of temperature.
Hmm, its pretty much a strait line for temperatures 270-300 K. hard to argue that the present Co2-doubling warming should be able to do something any other doubling should not do:
http://upload.wikimedia.org/wikipedia/commons/thumb/e/ef/Water_phase_diagram.svg/400px-Water_phase_diagram.svg.png
K.R. Frank
Frank,
I prefer this one 😉
http://upload.wikimedia.org/wikipedia/en/4/41/Relative_Humidity.png
Also, this is a useful resource for a comprehensive look at water vapor trends over the past few decades: http://www.cgd.ucar.edu/cas/Staff/Fasullo/refs/Trenberth2005FasulloSmith.pdf
Frank, that article was very needed. Good job!
Your next one, or maybe someone else, should be how the 0.54K is also very suspect. This is what you would come up with if performed in a lab on a bench with a small container and limited thickness. That however is not our atmosphere. Radiation in CO2’s bands are completely absorbed low in the troposphere so adding absorber molecules only shortens the path to first absorption (increased path length), seems totally different than in the flask in the lab. With a constant energy flowing per the temperature vertically through the atmosphere at any point, this seems to lead that the affect would be much less that the 0.54K (convertible to W/m2) much as a double log curve. I have seen another discussion many months ago that came up with about 1/10 of that 0.54K, should have paid more attention to that article and its logic or at least saved a link to it.
George E. Smith says:
September 8, 2010 at 11:31 am
…and that is the earth surface; which varies in Temperature over an extreme range of from 120 to 150 deg C from the coldest Antarctic midnight highlands; to the hottest midday tropical deserts; and over that range the surface emission varies by over an order of magnitude; from about double the 390 W/m^2 that Trenberth gives (corresponding to a 288 K Temperature, to about 1/6th of trenberth’s number for the coldest regions.”
You have again stated much of what I have said many times. If we accept CO2 absorbtion lines at 15 micro that has an associated temperture contained in it. That temperature is 200K, give or take. The earth at 300K (10 micro) does not radiate in the proper band for CO2 to absorb anything let alone radiate back down to heat the ground.
People like to use the black body formula to say this or that but totally ingnore Wien’s Law that the wave length is transmitting a temperature. W/m2 mean nothing if not associated with a frequency/wave length to tell us what the temperature could be. i.e. Under the transmitter for a 50000 W radio station should be very hot if you only consider W/m2.
I ran my microwave oven for 5 minutes on high and found no temperature change in the interior. Yet I have a 1000 W microwave oven, Amana I think, that given the size of the box should be putting several thousand W/m2 peak to peak in it.
When I was in the Navy, P2 and P3’s, had APS 20 and APS 37 radars that put out hundreds of thousands of watts of power. You could light neon bulbs, cook cans of soup and scare the family jewels but you could not heat the air with them.
re: wayne says: September 8, 2010 at 1:34 pm
Frank, just thought of one thing that may mean that enhance effect I just mentioned doesn’t occur at all, is not real. These are some areas where people trying to acclimate or re-acclimate to proper atmospheric physics need some real assistance. Oh well. We’ve gone over most of these points multiple times and it still has yet to completely gel in my mind yet.