Guest Post by Willis Eschenbach
This is an extension of the ideas I laid out as the Thunderstorm Thermostat Hypothesis on WUWT. For those who have not read it, I’ll wait here while you go there and read it … (dum de dum de dum) … (makes himself a cup of coffee) … OK, welcome back. Onwards.
The hypothesis in that paper is that clouds and thunderstorms, particularly in the tropics, control the earth’s temperature. In that paper, I showed that a falsifiable prediction of greater increase in clouds in the Eastern Pacific was supported by the satellite data. I got to thinking a couple of days ago about what other kinds of falsifiable predictions would flow from that hypothesis. I realized that one thing that should be true if my hypothesis were correct is that the climate sensitivity should be very low in the tropics.
I also figured out how I could calculate that sensitivity, by using the change in incoming solar energy (insolation) between summer and winter. The daily average top of atmosphere (TOA) insolation is shown in Figure 1.
Figure 1. Daily TOA insolation by latitude and day of the year. Phi (Φ) is the Latitude, and theta (Θ) is the day of the year expressed as an angle from zero to 360. Insolation is expressed in watts per square metre. SOURCE.
(As a side note, one thing that is not generally recognized is that the poles during summer get the highest daily average insolation of anywhere on earth. This is because, although they don’t get a lot of insolation even during the summer, they are getting it for 24 hours a day. This makes their daily average insolation much higher than other areas. But I digress …)
Now, the “climate sensitivity” is the relationship between an increase in what is called the “forcing” (the energy that heats the earth, in watts per square metre of earth surface) and the temperature of the earth in degrees Celsius. This is generally expressed as the amount of heating that would result from the forcing increase due to a doubling of CO2. A doubling of CO2 is estimated by the IPCC to increase the TOA forcing by 3.7 watts per metre squared (W/m2). The IPCC claims that the climate sensitivity is on the order of 3°C per doubling of CO2, with an error band from 2°C to 4.5°C.
My insight was that I could compare the winter insolation with the summer insolation. From that I could calculate how much the solar forcing increased from winter to summer. Then I could compare that with the change in temperature from winter to summer, and that would give me the climate sensitivity for each latitude band.
My new falsifiable predictions from my Thunderstorm Thermostat Hypothesis were as follows:
1 The climate sensitivity would be less near the equator than near the poles. This is because the almost-daily afternoon emergence of cumulus and thunderstorms is primarily a tropical phenomenon (although it also occurs in some temperate regions).
2 The sensitivity would be less in latitude bands which are mostly ocean. This is for three reasons. The first is because the ocean warms more slowly than the land, so a change in forcing will heat the land more. The second reason is that the presence of water reduces the effect of increasing forcing, due to energy going into evaporation rather than temperature change. Finally, where there is surface water more clouds and thunderstorms can form more easily.
3 Due to the temperature damping effect of the thunderstorms as explained in my Thunderstorm Thermostat Hypothesis, as well as the increase in cloud albedo from increasing temperatures, the climate sensitivity would be much, much lower than the canonical IPCC climate sensitivity of 3°C from a doubling of CO2.
4 Given the stability of the earth’s climate, the sensitivity would be quite small, with a global average not far from zero.
So those were my predictions. Figure 2 shows my results:
Figure 2. Climate sensitivity by latitude, in 20° bands. Blue bars show the sensitivity in each band. Yellow lines show the standard error in the measurement.
Note that all of my predictions based on my hypothesis have been confirmed. The sensitivity is greatest at the poles. The areas with the most ocean have lower sensitivity than the areas with lots of land. The sensitivity is much smaller than the IPCC value. And finally, the global average is not far from zero.
DISCUSSION
While my results are far below the canonical IPCC values, they are not without precedent in the scientific literature. In CO2-induced global warming: a skeptic’s view of potential climate change, Sherwood Idso gives the results of eight “natural experiments”. These are measurements of changes in temperature and corresponding forcing in various areas of the earth’s surface. The results of his experiments was a sensitivity of 0.3°C per doubling. This is still larger than my result of 0.05°C per doubling, but is much smaller than the IPCC results.
Kerr et al. argued that Idso’s results were incorrect because they failed to allow for the time that it takes the ocean to warm, viz:
A major failing, they say, is the omission of the ocean from Idso’s natural experiments, as he calls them. Those experiments extend over only a few months, while the surface layer of the ocean requires 6 to 8 years to respond significantly to a change in radiation.
I have always found this argument to be specious, for several reasons:
1 The only part of the ocean that is interacting with the atmosphere is the surface skin layer. The temperature of the lower layers is immaterial, as the evaporation, conduction and radiation from the ocean to the atmosphere are solely dependent on the skin layer.
2 The skin layer of the ocean, as well as the top ten metres or so of the ocean, responds quite quickly to increased forcing. It is much warmer in the summer than in the winter. More significantly, it is much warmer in the day than in the night, and in the afternoon than in the morning. It can heat and cool quite rapidly.
3 Heat does not mix downwards in the ocean very well. Warmer water rises to the surface, and cooler water sinks into the depths until it reaches a layer of equal temperature. As a result, waiting a while will not increase the warmth in the lower levels by much.
As a result, I would say that the difference between a year-long experiment such as the one I have done, and a six-year experiment, would be small. Perhaps it might as much as double my climate sensitivity values for the areas that are mostly ocean, or even triple them … but that makes no difference. Even tripled, the average global climate sensitivity would still be only on the order of 0.15°C per CO2 doubling, which is very, very small.
So, those are my results. I hold that they are derivable from my hypothesis that clouds and thunderstorms keep the earth’s temperature within a very narrow level. And I say that these results strongly support my hypothesis. Clouds, thunderstorms, and likely other as-yet unrecognized mechanisms hold the climate sensitivity to a value very near zero. And a corollary of that is that a doubling of CO2 would make a change in global temperature that is so small as to be unmeasurable.
In the Northern Hemisphere, for example, the hemispheric average temperature change winter to summer is about 5°C. This five degree change in temperature results from a winter to summer forcing change of no less than 155 watts/metre squared … and we’re supposed to worry about a forcing change of 3.7 W/m2 from a doubling of CO2???
The Southern Hemisphere shows the IPCC claim to be even more ridiculous. There, a winter to summer change in forcing of 182 W/m2 leads to a 2°C change in temperature … and we’re supposed to believe that a 3.7 W/m2 change in forcing will cause a 3° change in temperature? Even if my results were off by a factor of three, that’s still a cruel joke.
I think Willis’ analysis is incorrect (or maybe I understood it wrong). I’m not sure if it is considering differences between average winter and summer temperatures and average irradiances, or if it is considering top temperature diferences vs top irradiance differences, but in any case it would be wrong because it doesn’t account for the fact that the maximum and minimum temperatures do not occur at the same time that the maximum and minimum irradiances, there is a lag.
In the NH, maximum irradiance happens by mid June but maximum temperatures happen in late July or early August, when irradiance is already quite lower than the maximum. It would be incorrect to claim that the maximum irradiance in June can only warm the NH to as much as it is in early August. No, the potential is greater. Had the irradiance stayed as it was in mid June, temperatures in August would have been certainly higher. But irradiance had been declining for a while.
The interesting point for the irradiance is the point when temperatures stop going up and start going down. At that point, you can claim that the solar irradiance’s potential for warming the climate has been fully achieved. If there was more warming in the pipeline for the existing solar forcing at that point, temperatures would keep going up, and if the temperature was too high, it would have started to go down earlier.
So I think the procedure should be: substract the temperature of the hotest minus the coldest average day of the year for each latitude band, and the average solar forcings that exist IN THOSE PRECISE DAYS. Then you divide them and you get the true sensitivity. It should give a higher value than calculated by Willis, although I think that it will remain extremely low compared to the IPCC calculations.
So Willis can show minimal sensitivity. I can do better – negative sensitivity to solar forcing. In Paris, insolation declines after mid-summer, but the temperature does not peak till August. Declining insolation gives higher temperature = negative sensitivity. QED
Alternatively, this may just indicate that the Willis’ analysis is flawed and that Kerr et al. are correct
This analysis assumes that only the ocean skin is warmed over the annual cycle. This is correct, but Willis makes the further assumption that this layer is always thin, perhaps ten metres or so. In reality, the “ocean skin”, the mixed layer, can be much thicker, often over a hundred metres thick – see the climatology published by de Boyer Montegut.
Thanks Willis and Anthony.
This latest offering from you, Willis, is, once again, a model of rationality and brilliant communication skills. Your ability to explain complex concepts simply, clearly and in an entertaining way set a benchmark for clarity. Your postings and the ideas they spin off are real food for thought.
Anthony, I feel enormously fortunate and grateful that I have access to all that you include in WUWT. The Blogosphere enriches itself and becomes more powerful exponentially with the passing of each day with the exchange of ideas such as these.
Willis,
A nice extension of your hypothesis which I agree with in general terms.
However I think you are in much the same position as Bob Tisdale with his ENSO work in that although I find all that both of you say to be highly persuasive and in accordance with observations it does leave the longer term term climate change scenario unaccounted for.
I have tried to work backwards from the energy in/energy out balance whereas you and Bob are working forwards from specific observed phenomena. In fact Svensmark’s work has the same characteristic as does that of many others.
I don’t see any essential inconsistency between the three of us since your work could mesh with Bob’s and mine with both of you.
Nevertheless we do have to get the two approaches from different directions to meet in the middle somehow and I think that the best way to do that is to
note the undoubted effect on rates of energy flow from sea to air to space that results from latitudinal shifts in the global air circulation systems.
Such a shift can be linked both to Bob’s ENSO phenomena and your tropical thermostat and to my emphasis on the changing speed of the global hydrological cycle which I contend is the true climate governor globally.
My favoured source of the variations in the rate of energy flow through the Earth system is the oceans rather than the sun, atmosphere or cosmic rays. More specifically I suspect variability in temperatures along the horizontal line of the thermohaline circulation. Such irregularities need not be large in order to produce large effects on the air above because water holds so much more energy than air.
However I have been unable to find adequate data on such matters so far. The thermohaline circulation is generally assumed to be very stable and thermally constant but since everything in nature varies I have my doubts. The MWP to LIA to modern warm period could well be reflected by subtle temperature variations along that circulation taking 1000 to 1500 years to complete a circuit. Can anyone rebut that for me ?
Willis, as ever your posts are illuminating. WRT the argument that the oceans and circulation currents are acting as short-term sinks dampening the observed sensitivity, surely this can be estimated or at least bounded by examining the lags between longest day and hottest day?
The sink reversal after the longest day should be symmetric to a first approximation to the flow leading up to the longest day. I’m no physicist but the magnitude should then be calculable?
Alexander Harvey (22:31:20)
I understand what you are saying. When energy hits the earths surface, it does not all go directly to warming of the surface. Depending on the admittance, it is partitioned. Some of it warms the surface, and some of it passes through the surface and goes to warm the substrate. Thus, if we have cyclical forcing, the change in the surface temperature of the solid is not proportional to the incoming forcing. This would seem to indicate that admissivity is an issue.
But if the system is at equilibrium, that excess heat in the substrate has to come out of the substrate. And when it does so, it has to warm the surrounding air, either by conduction or radiation. So overall, regardless of the emissivity, by the end of the cycle all of the incoming energy has to warm the surrounding air. And that is what we are measuring, surface air temperature.
Some of the warming of the air occurs directly, as a result of the direct warming of the skin surface. And the rest of the air warming occurs when the rest of the energy (the partitioned amount which warmed the substrate rather than the surface) comes back to the surface and then warms the air.
At least that’s how I see it, although I could well be wrong, wouldn’t be the first time. Fight my ignorance here, and explain why admittance makes a difference when we are only talking about surface air temperature. Regardless of the admittance, all of the incoming solar energy ends up warming the air, albeit with a slight delay for part of the energy. Although this will slightly decrease the peak temperatures, it won’t affect the average temperatures as long as the averaging period encompasses the peak. I don’t see how this will make the huge difference that you claim.
Many thanks for your participation,
w.
Fig. 1 in Mr. Eschenbach’s article is the theoretical daily-average solar insolation at the top of the atmosphere. Due to to the low solar elevation angle at a given polar area during the short time span around the summer solstice, insolation reaching sea level is much less than shown in Figure 1, due to the extra thickness of atmosphere existing in the path of the solar radiation, even though the polar region receives 24 hours of sunlight. This extra atmospheric thickness produces greater amounts of atmospheric absorption and scattering, resulting in substantially greater attenuation of the solar insolation at the poles during the corresponding summer solstice. I also note that Fig. 1 appears to have a couple of technical problems regarding the 500 and 550 watts per sq. meter shaded areas for positive values of Phi (Φ).
This 2-tiered figure, by William M. Connolley using HadCM3 data, depicts the annual mean solar insolation, and allows comparison between top of the atmosphere and at the earth’s surface. The observer will notice the substantial differences due to the atmosphere, especially at the polar regions.
http://en.wikipedia.org/wiki/File:Insolation.png.
This figure, by Robert A. Rohde, depicts the direct solar radiation spectrum (for a 90 degree solar elevation, at the zenith), for both at the top of the atmosphere (yellow), and at sea level (red). Notice the large and frequent H2O absorption bands in the infrared spectrum (750nm and greater wavelengths), dwarfing the CO2 absorption bands. The absorption bands shown are too short for earth long wave radiation (outgoing), thus mainly attenuate incoming solar radiation. Many persons viewing this graph for the first time will be surprised to learn that greenhouse gases (mainly H2O) also play a significant role in absorbing incoming sunlight in the shorter IR region (750 nm thru 2500 nm).
http://www.globalwarmingart.com/wiki/File:Solar_Spectrum_png
Hi Alex,
I don’t have a source, I just made it up to provoke discussion.
I can hit the paragraph you quoted over the boundary (out of the ballpark if you insist)
1) Willis is making a quantitative argument and that para has no numbers in it. If the author can put an upper bound in Joules per annum crossing the equator then you win the point, until then please try harder.
2) In summer ( I mean January) the hottest place is not the equator (how could it be, it’s not directly under the sun at that time), The hot spot is further south. So heat does flow north.
I bet is a “lot” too.
The point is how weakly coupled does “weakly coupled” really mean.
stevengoddard (22:34:35)
So do you also object to the IPCC calculating the climate sensitivity for the entire planet?
Interesting, so clouds and thunderstorms control the Earths temperature. The question is, what controls the clouds and thunderstorms??
Corbyn would say solar particles control thunderstorms.
Svensmark would say cosmic rays control the clouds.
Richard Telford (00:58:02)
Isn’t the ocean skin the top Imm which is 0.3C cooler than the ocean bulk below ?
Sunlight gets into the ocean bulk below to a depth of 100 metres or more depending on wavelength and water turbidity.
At the very top few microns of the ocean skin is the Knudsen layer where all the evaporative action takes place so that all downwelling IR (and more, thus the cooling of that 1mm) is converted to latent heat of evaporation.
Hi Willis,
I think this is a promising approach, but needs some further consideration on the absorption of energy by the ocean.
You said:
3 Heat does not mix downwards in the ocean very well. Warmer water rises to the surface, and cooler water sinks into the depths until it reaches a layer of equal temperature. As a result, waiting a while will not increase the warmth in the lower levels by much.
I did some calcs last year, verified by Leif Svalgaard, which show that the sea level rise attributable to temperature increase (thermal expansion of the ocean, the steric component) between 1993 and 2003 of around 5400Km^3 equates to a net increase in ocean heat content of @14×10^23J. This is equivalent to @4W/m^2 additional forcing, far greater than anything co2 can do and probably due to reduced cloud cover during active solar cycles 22 & 23.
This increase in temperature spread proportionally right down to the thermocline in a fairly linear manner from the bottom of the mixed surface layer. The thermocline in the tropics can be as little as 30m, but as much as 1200m in the temperate latitudes. Therefore, although it is counterintuitive to the warm water rises commonsense, energy must have been mixed downwards on at least a decadal scale. This is infact confirmed by the 0.15C rise in the average temperature of the top 700m of global ocean over the same time period.
People on the skeptical side are very resistant to this logical truth. I think it’s because they have an aversion to any conception which could admit of some ‘heat in the pipeline’. However, the point is that it is Solar derived heat, nothing to do with co2. The way to get past it is to simply consider where else the extra energy could go. It can only escape from the ocean at a rate the atmosphere permits: more energy out, more evaporation, more water vapour, more humidity, hotter atmosphere, less temperature differential between atmosphere and ocean – slower heat loss from ocean. If the excess energy from a hyperactive sun can’t escape upwards, it must get mixed downwards by tidal action and subducting currents near the poles.
My simple solar-ocean energy model which works using a TSI proxy (sunspot number) and a simple ocean heat content estimation tehnique (cumulative count of sunspot numbers above and below the ocean neutral value emirically determined from the change in TSI over the solar cycle compared to SST’s) shows that the heat content changes on multidecadal scales at least, possibly centennial.
This opens the way for a solar explanation for temperature variation on the longer timescale. In my view your brilliantly described thunderstorm mechanism is more about the redistribution of heat within the Earth-Ocean climate system than a planet wide thermostat. Your ideas, coupled with Stephen Wildes ideas about the equatorial-polar shifts of the jet streams (and thus Hadley Cell bondaries) could account for much of the intra terrestrial variation we see in the temperature records of individual countries relative to each other. Ferenc Mickolczi’s theory on the dynamic equilibrium of the atmosphere as a whole, and my ideas on amplified centennial solar variation modulaed by OHC might account for longer term variation of the global temperature.
Mike Jonas (22:53:47) : edit
… snip more on cosmic rays …
I am looking at changes in average temperature based on changes in average forcing. Thus, it is not really a “year-long experiment”, that’s a bit of a misnomer. It is not studying the evolution of the system over time.
—–
Well, for the system to come to total equilibrium, the temperature of the entire planet down to the core would have to change … so we’re not talking about total equilibration.
By looking at the lag between peak insolation and peak temperature (about a month), it appears that if the season’s insolation forcing were to continue at a constant value the majority of the equilibration would occur on the same timescale.
Willis Eschenbach
“1 The only part of the ocean that is interacting with the atmosphere is the surface skin layer. The temperature of the lower layers is immaterial, as the evaporation, conduction and radiation from the ocean to the atmosphere are solely dependent on the skin layer.”
This is an assumption leading to incorrect conclusion.
Temperature of the lower layers are the most crucial in the regions of heath release to the atmosphere.
http://www.windows.ucar.edu/earth/Water/images/thermohaline_circulation_conveyor_belt_big.gif
Warm waters of Arctic are at some depth due to higher salinity (specific gravity)
http://www.divediscover.whoi.edu/arctic/images/ArcticCurrents-labels.jpg
Arctic currents are the engine of the heat transport across the North Atlantic Ocean.
Just an addendum to my post at (02:14:54)
Willis’ thermostat may well operate at a planet wide level if the mechanism he descibes affects the rate of heat lost to space, which given the transport of energy up through the centre of the thunderstorm systems seems possible if the variation in storm intensity varies sufficiently on longer timescales. Could there be a hookup with Anthony’s posts on hurricane energy over the last 30 years here?
Relevant to the simple v complex thread, there is a story that Thomas Edison, towards the end of his career was given several bright young men to “help” him, which he did not really want. One day, the young men came to Edison and asked for something to do. Exasperated, he gave them a light bulb and asked them to determine it’s internal volume. The young men went away and laboured long with calipers, rulers, slide rules etc and eventually came back with an answer. Edison took one look and said, “Your at least 10% out”. He drilled a small hole in the bulb, poured in water until full and then poured it into a measuring cylinder. The young men were 10% out.
This is the difference between an “expert” and an “inpert”!
Oops. Grammatical error. Smacks head. “Your at least 10% out” should read “You’re at least 10% out”. Edison was American so may be he did misspell it!
Re: John Ritson (Mar 1 02:00),
“If the author can put an upper bound in Joules per annum crossing the equator then you win the point, until then please try harder.”
You are mixing your metaphors. Is this cricket, baseball or tennis?
If it’s cricket or baseball, I am batting and you are bowling/pitching. And you haven’t bowled the ball yet. You need to justify your assertion first.
El Ninjo, blocking high’s and the most negative AO since the 50’s show how irrelevant the Global temperature measurements really are and how insignificant the role of CO2 is.
http://icecap.us/images/uploads/AO.JPG From icecap.us
An analysis like this would be more persuasive and more thorough if it included a heat balance. Energy is conserved, temperature is not. This allows setting up a nice balance sheet. Most energy is in the form of heat. Some of it is in phase change.
Figuring the temperature response of the earth to an a change in energy inputs is like computing the heat capacity. And all the heat capacities of water and air are known. The capacity of land is probably available as well. The concept of “Sensitivity” sounds to me exactly like the physics concept of heat capacity. Is it not?
Willis,
. . . and to the memory of Jane Austen, who will probably forgive you : )
John
Willis,
Great theory but I think there is an additional factor which augments your hypothesis. In brief your suggestion is that increased heat trapped at the equatorial regions must result in increased storms/clouds/convection and so on that move heat upward in the atmosphere and outward toward the poles.
With that thought in mind, consider the absorption spectrum of all the “greenhouse” gases combined which has a window of almost zero in the 10 to 12 micron range. There’s a pretty good graphic from Wikipedia that shows this at
http://upload.wikimedia.org/wikipedia/commons/7/7c/Atmospheric_Transmission.png
This essentially defines the “sweet spot” for longwave to escape into space no matter what the concentration of CO2, water vapour, ozone and so on, as if it was an “open window”. Rough guesstimate (ie mine) is the sweet spot ranges from -35 to about +15 C. So, consider the implications of that to your original hypothesis which is that the earth regulator maintains a temperature of about plus or minus 3 degrees.
Since the tropics are already above the +15 C mark, they are in the “greenhouse zone” and trap heat. They then move heat toward the temperate zone and poles which are in the temperature range where longwave is not absorbed by GHG, ie below +15 C. Combine that with radiance rising proportional to T^4, and the efficiency with which excess heat would be radiated into space by the temperate and arctic zones would overwhelm even very large increases in forcing with only 2 or 3 degrees of temperature rise NO MATTER HOW MUCH CO2 AND WATER VAPOUR. The only way for forcing to break through that upper limit would be to inject so much heat so fast that it would drive most of the planet surface above the 15 C mark and “close the window”.
Going the other way, this same mechanism would define the low end as well. In a cooling cycle the amount of energy being pushed from tropics to poles would drop, causing the poles to cool down. As they drop in temperature, the coldest parts of the year start to hit into -35. As they do, the GHG “open window” starts to close, sending heat that used to be zipping out to space back to earth. The cooler the earth gets, the larger the area at the poles where the GHG window now is closing and retaining heat. Those ice sheats could only get so far before the additional heat being retained by the coldest parts of the planet would balance off the cooling mechanisms.
I think it no coincidence that I live in Winnipeg, a city known for cold winters, which features a -35 to -40 cold snap once or twice every winter, yet cities far to the north of Winnipeg get very little colder. Winnipeg is close to the border, so just above the 49th parallel. Here’s the COI graph of temps from the 80th parallel:
http://ocean.dmi.dk/arctic/meant80n.uk.php
As you can see, when temps start hitting downward to -35, the “open window” starts to close making it almost impossible to go more than another few degrees down because GHG’s start retaining heat. Winnipeg’s low temp extremes are very little different from low temp extremes 30 degrees latitude farther north. Just as you would need a stupendous amount of energy to jump the whole planet surface temp ABOVE the “open window” to get serious warming, you would need a stupendous amount of cooling to get the whole planet BELOW the “open window”.
It seems to me that the thermostat proposed by Willis is the mechanism by which heat is moved around the planet, more the ventilation system than the thermostat. That “open window” from 10 to 12 microns sets an upper limit that small amounts of forcing can’t get past, and a lower limit that starts retaining heat as soon as it cools down, keeping the range within very tight boundaries.
…a 3.7 W/m2 change in forcing will cause a 3° change in temperature
.. and the missing words are “over the long term” (probably 30 – 50 years).
The point about the theory of AGW is that the summer/winter oscillation in forcing is entirely predictable and stable. Other than the solar and Milankovitch cycles there is no significant change in total insolation from year to year. Therefore the temperature of the atmosphere has had thousands of years to adjust to a totally regular and predictable rise and fall in energy inputs over the calendar year. Effectively the “burner” under the saucepan has been set.
The problem with increased CO2 in the atmosphere is that it changes this long-established balance of insolation (energy in) and radiation from the stratosphere (energy out) by not letting quite as much energy out of the atmosphere as previously. More energy is therefore “trapped” in the atmosphere. Somebody has put a lid on the saucepan!
What the climate models try and do is to determine what the effect of this extra trapped energy will be.
To be honest I have not a clue (although I have some suspicions), and I don’t reckon the modellers have the answer (yet) either – because of their poor understanding of the water vapour and cloud feedbacks both at low level and in the stratosphere.
However I think it is completely spurious to try and use the relationship of the normal seasonal changes in insolation with the air temperature as somehow analogous to a long term change in the radiative balance of the atmosphere. This whole paper is basically a red herring.
I am more and more coming round to the view that the only skeptic worth reading in the blogosphere is Roy Spencer. He seems to be the only one who is actually doing real science and is targeting his efforts on the big gaps in knowledge with one of the few tools that may actually be able to quantify these complex feedbacks on a global scale – the satellites.
Your theory is quite interesting but as far as i can tell it rests on the asumption that winter is a static situation and that summer is a static situation. If the summer heatflux was kept hypotheticaly constant for 10 years and the winter heaqtflux was kept hypotheticaly constant for 10 years you would get a much higher delta T and thus your sensitivity would go up.
In other words when you reach the maximum heatflux in the summer the temperature would continue to rise if the heatflux stayed that high and something similar would happen in the winter.
You have compensate for this somehow.
Another problem is thast the sensitivity is probably not linear as a function of forcing.
What is the third measure – the daily average insolation – is it Wm^-2?