Sense and Sensitivity

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.

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March 1, 2010 11:34 am

Thanks for the additional info, Willis.
Especially the info on your dt calculations.
If I have this right, for any particular latitude band, you are calculating
Tave_summer = [Tmar + Tapr + Tmay + Tjun +Tjul + Taug] / 6
Tave_winter = [Tsep + Toct + Tnov + Tdec +Tjan + Tfeb] / 6
dT = Tave_summer – Tave_winter
If you will humor me, I have a couple of additional questions.
How are you calculating T for any particular month in a particular latitude band?
Which data series are you using?
How do you extract the data for a particular latitude band?
Are you using the same method to get a summer and winter RFave with dRF = abs(RFave_summer – RFave_winter)?
And as someone asked above,
Are you using the TOA (Top of Atmosphere) insolation or insolation at ground?
From you comment on clouds as feedback and your wikipic,
I’m guessing TOA.

March 1, 2010 11:57 am

johnnythelowery (06:42:54) : Said
“I miss Manuel already. His Iron sun and all that(what ever that is-still can’t figure out what the hell he’s barking on about!). Can I petition for a month long ban instead of life time. I’m sure he’ll behave in the future. It’s just to see a fellow realist get a smack down here at WUWT.”
Can I put in a plea for a months ban as well? As you say Anthony he is always polite so that helps the nature of the general discourse. Even better, in my old school they used to promote the bad boys to positions of responsibility. How about asking Manuel to provide the material for his own thread? We can read, learn, then go wildly off topic 🙂
tonyb

Grizzled Wrenchbender
March 1, 2010 11:58 am

The annual sensitivity is dT/dF for the 6 month extremes… but what of he _daily_ sensitivity? The day-night temperature swings in deserts can show about 40 K change from about 1000 W/m2 forcing… still only 0.045 K.m2/W, but obviously the transient admittances are even more important on this short time scale. I don’t have a conclusion, just a suggestion that you dig a bit deeper.

JJ
March 1, 2010 12:03 pm

Willis,
You are dealing with a cyclic system, and not permitting it to equilibrate. Apart from the transfer of energy from the high to low insolation areas, winter temps are warmer than the winter solar flux could sustain because the earth is coming off a summer. Summer temps are cooler than the additional flux would support for the inverse reason. Calculating the sensitivity as the seasonal difference underestimates vs an increase in both over many cycles.
I concur with Goddard that looking at something like mutli year changes in solar flux due to solar cycles would be more productive.

Steve Goddard
March 1, 2010 12:12 pm

Grizzled,
How hot do you think it would get in the desert, if the sun stayed up high in the sky for 30 hours instead of just 8? Maybe 90C?
You can’t draw any conclusions about sensitivity until the system gets closer to equilibrium. I’ve fried eggs on top of Coleman coolers in the desert.

johnnythelowery
March 1, 2010 12:14 pm

Tonyb
Regarding Oliver. He’s got his own Headline/Blog and Comments thread regarding his Neutron Star surrounded by an Iron casing theory of the center of the sun. Check it out. it’s very interesting. Don’t know why he wouldn’t listen to Anthony.
http://tallbloke.wordpress.com

March 1, 2010 12:14 pm

Willis
I observe many climatologists to be confused about what is meant by “falsifiable.” As an effect of this confusion has been to base ultra-expensive public policy proposals upon unfalsifiable and thus unscientific climate models, I’d like to dispel their confusion. I hope you won’t be offended if I use a critique of your article as the vehicle for an attempt at doing so.
You’ve stopped short of providing a falsifiable hypothesis. To make your hypothesis falsifiable, you’d need to cast it into the form of a predictive model. Each prediction of such a model would state the outcome of an independent statistical event. The totality of such events would form the statistical population of any study in which your model would be tested. In a falsifiable hypothesis, the set of all possible outcomes would be described in sufficient detail for the actual outcomes to be measured.

Alexander Harvey
March 1, 2010 1:20 pm

Wiilis,
If I have understood you correctly you are looking at the ratio of the principal 12 month components of the seasonal variation of the flux (F’) to the seasonal variation of the temperature (T’).
F’ = T’*Y {where Y is the admittance}.
Or T’=F’/Y
Now for this sinusoidal component we have:
F’ = F*e^(iwt) {where F is the amplitude of that component, i is root -1, w the angular frequency and t the time.
and T’ = T*e^(iwt+p) {where T is the amplititude, and p the phase angle}
so T*e^(iwt+p) = F*e^(iwt)/Y
or T*e^(ip) = F/Y where Y is a complex number {the vector e^ip is just a rotation, it has unit length}
Now for admittances in parallel (as in this case) Y is additive
Let us say:
Y = Ys + Ye {where Ys is the admittance into space and Ye the sum of the admittances into the environment}.
I think you are looking for Ys = Y-Ye {where Y is your measured F/T}
The climate sensitivity (CS) when given as degrees K per doubling equates to
Ys = 3.7W/CS so CS = 3.7W/Ys
Now for your value of 0.15K, your recovered value for Ys is:
Ys = 3.7/.15 =~ 25W/K
Now the admittance of 1 m^3 of well mixed water is approximately
4200000*2*pi/(365.25*24*3600)) for a cycle with a period of one year
=~ 0.84W/K
and guestimates for the total Admittance for the ocean could range from 42 to 84 W/K
similarly the Admittance of the atmosphere is around 3W/K and the earth’s is very varied and not all that big.
So Ye is ~ 3W/K over land and (45-87)W/K over the oceans.
So over the oceans T = 2K could imply an oceanic flux amplitude of 90-176 W {I have left out all the per metre squared bits too save mess}
Now it is likely that you will find that on the western margins of the temperate oceans the ocenic flux amplitude will well exceed the solar amplitude. This is to be expected due to flux from the atmosphere which has passed over a region of high temperature amplitudes. The reverse effect is likely to be found over the eastern seaboards of the contintents.
I think that well isolated parts of the temperate oceans have T=~2.5K, so it is quite possible that almost the entire flux is oceanic or , Y =~ Yo {the oceanic admittance}.
Now the figures for the oceanic admittance are guestimates but figures much lower than 40W/K seem unlikely to me.
Now you are looking for Ys = Y – Ye, but Ye = Yo + Ya {Ya = atmospheric admittance} is likely to be bigger than Y over parts of the ocean and almost equal to it in isolated parts of the ocean. The reason it can be bigger is that the local Y = F/T {where F is the local solar flux amplitude} ignores the additional flux from the atmosphere as it passes from land to ocean.
Over the land Y will be greater than Ye {Ye =~ Ya} where prevailing winds come from the ocean and will decline in value towards Ye in isolated continental regions {actually really only in Mongolia/Eastern Siberia do they get close}.
The atmospheric Ya is a common factor in Ye across the globe and simple calculation implies that if over land Ys was zero then Y=Ye and a 150W value for F would imply a maximum for T ~ 150/3 = 50K (which is only around 1.5 times the Siberian amplitude, so the slack there is just 1.5W/K . The IPPC’s CS of 3K equates to 0.8W/K which is perhaps a little low. I am not going to argue about precise values for F as they differ from TOA insolation value anyway.
Unfortunately the problem is ill-conditioned in that over the oceans Y and Ye are similar in magnitude and Ye can be greater than Y=Fsolar/T locally, and the uncertainties in Ye are large and you need to determine the reciprocal of Y-Ye to find CS = 3.7W/(Y-Ye).
Now in all the above I have only dealt with the amplitudes of the variations, This is justified becuase we are treating Y = F’/T’ {variations in amplitude} as a stand in for Y = dF/dT {i.e linearity has been assumed over the ranges of the amplitudes}, the mean values of total Flux and absolute surface tmperature are of no interest, we only need the amplitudes of the local variations.
So readers be warned, arguments based on the total values of solar flux and surfaces temperatures are not necessarily relevant here, we are looking only for the slope dF/dT. So for instance the average flux from say the equator to the pole is of no interest only the amplitudes of any seasonal component of such fluxes would be relevant.
Alex

Editor
March 1, 2010 1:24 pm

Willis Eschenbach (02:22:25) : “I am looking at changes in average temperature based on changes in average forcing.”
What I was getting at wrt clouds is this : if a change in GCRs, say, caused a change in cloud cover at a point in time during your experiment, then it would alter the temperature without altering TOA insolation. In the context of your experiment, that’s a forcing that isn’t an insolation feedback. That would invalidate your basic assumptions.
Assuming that such [non-feedback] forcings are not an annual phenomenon, doing your experiment over multiple years could eliminate them as a possible factor.
Willis “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.”
Sounds reasonable, but I’m not sure that’s a valid assumption. Analogy : Water on a stove takes a long time to boil, but stops warming almost immediately when removed. [“almost” = heat in transit in the pot].

C.W. Schoneveld
March 1, 2010 1:28 pm

The hockey team could label their their AGW theory as Pride and Prejudice

March 1, 2010 1:39 pm

Eschenbach: I am looking at the relationship between TOA forcing and temperature.
I guess that brings up another question. Are you modeling the RF based on an assumed or averaged Solar Constant (‘So’ in the wiki article on insolation) or are you using a measured value? If you are using measurements, which data series?