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.
Mesa (18:14:02)
That study appears to do what I have done (except with models instead of observations), but is actually doing something quite different.
They take the net of all of the various changes, changes in solar and changes in clouds and changes in clouds and changes in water vapour and in ice coverage and all the rest, and they call that the forcing. Then they compare that to the temperature change, and get the IPCC canonical number of about 3°C for a doubling of CO2.
But the truth is that the change in the insolation is the only true change in forcing. The rest are all responses to the change in insolation. Thus, the changes in say the clouds tend to reduce the effect of the insolation change. But they are not an independent change, they are a negative feedback to the independent change in the insolation. Thus, they should not be counted as part of the forcing.
Because when we go from winter to summer, the driver of the change is the change in the sun. The rest are feedbacks, either negative or positive, in response to the change in insolation. Winter turns to summer because of changes in the sun, not because of changes in the clouds.
As a result, their models are not measuring what they claim to be measuring.
Graeme W (17:55:14)
“It’s an interesting theory and I think it deserves more research, but unless I’ve got it wrong, there appears to be one significant issue that it doesn’t explain:
What caused the MWP and LIA?”
Heck, what causes the ice ages? I don’t see how this question has any bearing on the concept. You can still have cosmic rays, Milankovich cycles, etc.
I’m sorry, but I didn’t find any of them convincing.
You suggested geography, which may be used to explain the ice ages, but geological time frames (required for geography changes) are too long for the MWP and LIA.
Ocean current and wind pattern changes are definitely a possibility, but then we have to explain why they’re changing. If we can show that they did change and at appropriate times, then that’s another step towards supporting your theory. But we’d need to find such evidence first. If you like, that’s another possible falsifiable aspect of that part of the theory.
Albedo changes would need to be justified by some evidence that it actually occurred. You’ve suggested aerosols like dust, etc. (presumably from volcanoes, etc.) but wouldn’t the system autocorrect to a large degree after those have disappeared from the atmosphere? We’re talking about decades, if not a century or more of time, after all. Whatever causes the change has to persist for that period if it’s to be a reasonable hypothesis.
I didn’t like your suggestion of solar variation, because the entire basis of your theory appears to be around less dependency on variation from the Sun.
Please keep thinking about this, because it sounds like a very promising theory. It’ll just be a matter of seeing how well it stands up to the stones (or thunderstorms) thrown at it.
Hello Willis,
Interesting post. I note only that much, if not most, of the heat lost from the hemisphere that is in winter is transported from the tropics. So the local temperature change is not an isolated response to lower solar heating in winer. Were it possible to actually isolate a region (say everything above the arctic circle, or everything between 40 and 50 degrees) to see its independent seasonal response, then your analysis would be better able to identify the sensitivity. But since such regional isolation is not possible, I think it is difficult to draw solid conclusions about overall sensitivity from seasonal temperature changes.
I agree that moist convection (including thunder storms of course) in the tropics does a lot of cooling, but I do not known how to relate that to climate sensitivity. The discrepancy between the GCM predicted temperature profiles and the measured temperature profiles of the troposphere seems to indicate that the CGM’s underestimate heat transport due to moist convection. Another (perhaps less well known) discrepancy between measurements and the models is the quantity of tropical rainfall: the GCM’s consistently underestimate tropical evaporation and tropical rainfall (which are both good proxies for moist convective heat transport/surface cooling), and so seem to underestimate heat transport via moist convection.
Max Hugoson (19:02:30)
Again, all of the changes in clouds are not drivers of the change from winter to summer. They are responses, also known as feedbacks. As such, they don’t enter into the calculation of sensitivity.
chris y (18:51:48) : edit
Per doubling. It’s ∆T/∆F * 3.7 W/m2 per doubling.
Phil M. (18:36:10)
You misunderstand the purpose of peer review. It is a recent invention, and is only designed to keep real junk from getting printed in a magazine that is designed to make money.
As such, it is only the most surface examination of the issues. I’ve gotten much more stringent reviews here on WUWT than I have gotten from peer reviewers (and less politicised attacks masquerading as reviews as well).
Graeme W (19:19:40) : edit
OK, then you’ll have to propose your own. As I said, I don’t know the answer to the question, and have only posted possibilities. Another one might be increasing aerosols darkening the color of the clouds. Your turn.
But if that’s the only problem with my thunderstorm thermostat hypothesis, I’m a happy man …
Steve Fitzpatrick (19:23:54)
As you point out, all of these are net changes. Part of the reason that the tropics don’t warm much is that they export excess heat. Part of the reason the poles do warm is that they receive the exported heat. However, that does not stop us from noting that for the Southern Hemisphere as a whole, a 188 W/m2 increase in forcing leads to a 2°C temperature increase …
The models are definitely known to underestimate the tropics-to-pole energy transport, although I don’t have the citation to hand. However, again I say that none of that negates my conclusion. When the forcing goes up in the Southern Hemisphere by 188 W/m2, the surface and atmospheric conditions rearrange themselves such that the surface air temperature only increases by 2°C. That is a very low sensitivity.
[quote Willis Eschenbach (18:25:33) : ]
No code, it was done in Excel.
[/quote]
I don’t suppose this is available online? I’d really like to see it.
BTW, nice post and very much in line with how view things.
A few questions about this:
(1.) it is my understanding that the outgoing heat flux, watts per square meter is proportional to the fourth power of the absolute temperature of the radiating surface — is this detail embedded in your calculations? The same is true of the incoming flux except that I believe it is attenuated by a relative distance (from the sun) squared.
(2.) Are you basing your calculations on what might be called the static radiative R-factor of the atmosphere at the surface or at the top of the convection column or some mean effective combination of the two? I believe, on average, the tropopause is above 75 percent of the atmosphere in general and perhaps 90 percent at the tropics so there would be less absorption to outer space from these levels
Interesting proposition Willis.
I also have a strong suspicion thermal convection and cloud development is a very strong thermostat effect.
Sometimes this sort of back of the envelope analysis is more powerful than sophisticated modeling because it is based on the real physics even if we do not understand all the physics we know the results are real.
It would be interesting to see if the current models can in any way replicate this seasonal, latitude band behavior. If not — the model is wrong period.
Larry
I very much like the thermostat hypothesis and the extension here. I’ve been reading WattsUpWithThat and about six books on the weather over the last two years and I have finally put together a conceptual frame on how the climate could respond to greenhouse gasses.
From the weather books I found the well known but somewhat surprising information that the coldest part of the atmosphere is at the tropopause over the equator. The tropopause is at 55,000 feet and -80°C over the tropics, and is at 25,000 feet and -55°C over the poles. This is because the warm moist air over the tropics rises to much higher altitudes before the latent heat of water condensation is used up. The lapse rate of -6.5°C/km continues to a higher altitude. Adding heat and moisture to the tropics should therefore cause the tropopause to rise. Thunderstorms should increase per the Thermostat Hypothesis.
I find some of the descriptions on how CO2 should cause warming naive. In the troposphere CO2 does not simply absorb upward traveling IR from the ground and re-emit it in all directions and return some of the energy to the surface. Long before an excited CO2 molecule will decay, it will collide with other molecules in the atmosphere. CO2 will only emit IR in compliance with the temperature at that altitude. The IR that the CO2 absorbs heats that entire level of the atmosphere. Because the atmosphere at that level is a little warmer, not quite as much water vapor will condense until it gets to a higher altitude so the tropopause should rise.
From Miskolcki’s paper we have the claim that the atmosphere will maintain a constant optical density even as CO2 rises. He claims that water vapor in the atmosphere will decrease as CO2 rises to maintain this constant optical density. This has been remarkably confirmed by a drop in the humidity at the 300 mb level and above over the last 50 years.
Now consider the stratosphere. In the stratosphere the temperature rises with altitude so there is little convection and heat transport is dominated by radiation. The stratosphere must be quite dry as it is in contact with the very cold tropopause so the dew point should equal the temperature at the tropopause. If the tropopause rises, it becomes colder and the stratosphere should become dryer. This could be the mechanism by which Miskolcki’s constant optical density works. The rise in IR absorption in the CO2 bands is made up for by a drop in the IR water bands in the stratosphere. If this is right, the optical density in the troposphere should increase with greenhouse gasses and the optical density only remains constant through the whole depth of the atmosphere.
Finally we have the recent paper by Michael Beenstock1 and Yaniv Reingewertz1
http://wattsupwiththat.com/2010/02/14/new-paper-on/
They analyzed the temperature and CO2 records and found that the rates of change did not match and CO2 did not cause warming in the historical record. However they did find that a change in the CO2 could have caused a short term change in the temperature although once the CO2 stabilized the temperature returned to the stating point. This would be consistent with increased CO2 causing the tropopause to rise as it would take some time for the dew point of the stratosphere to drop as there is no convection to drive a rapid change as the tropopause cools.
The climate changes we have seen seem to be well explained by the changes in the sun and amplification of these changes by cosmic rays per Svensmark and “The Chilling Stars”
LOL! Yes, from my very limited viewpoint, that’s my only problem with your theory. It is, as I understand it, widely accepted that clouds affect climate, and your theory provides a mechanism that explains how this regulates global temperatures (driven from the tropics).
As for my own theories, I know I don’t know enough to suggest anything sensible. Of your suggestions, the ocean current one seems worth investigating further. Is there any proxies that could be used to get a feel for major ocean currents over the last 1000 years? I’m not asking for much….
If I was pushed to suggest other possibilities, I’d look at the effectiveness of your theoretical process in non-tropical regions. If it’s less effective, then that may explain why a long term variation such as the MWP and LIA could exist (the ‘correction’ takes longer or isn’t as efficient). That would also counter any arguments about the MWP/LIA not being global in nature — it would suggest that they may more attributes of mid-range latitudes, and not the tropics. I don’t know enough to know if that’s a reasonable hypothesis or is already contradicted by historical evidence.
Willis,
Nice going.
Seems to me you’ve nailed the order of magnitude at least. Anybody quibbling with your numbers is going to make not a lot of difference to your conclusion
I think this was summed up at JunkScience by the short statement “summer ends”.
That alone rules out runaway effects.
You would think that the people doing the GCMs would do some simple calculations like this to see if the hugely complex models make any physical sense at all. I think think you’ve shown that they don’t and it will be hard to overturn your hypothesis as there doesn’t seem to be any hidden reservoir for the heat from doubling CO2.
magicjava (20:03:39)
Well, saying it’s not “user friendly” would not cover the situation, even “user unfriendly” doesn’t touch it … is there such a thing as “user aggressive”?
However, I’ll post the temperature and the insolation data. The insolation data was digitized from the chart in the head post, so it isn’t totally accurate. If anyone has access to the actual data shown in the head post let me know. Hang on … OK, thanks for waiting, it’s here.
(To digitize the graphic in the head post, I first traced over each section in Vectorworks, my architectural graphics application. I added a database that held the mid-value of the insolation for each section. Then I wrote a program to sample it every degree in both directions, and average it in 5×5° gridcells. Of course, in some areas all of the gridcell was in a single region, so subtle variations were not caught … but it doesn’t affect the results much.)
Willis,
Great, thought provoking work as always. Especially the comments regarding forcing, I always thought it was somewhat insane to consider anything other than the sun as a forcing. Glad to see I’m not alone.
If you’re ever in my neck of the woods I owe you a beer – that goes for Anthony and the mod squad too.
Spector (20:11:14) : edit
My calculations do not include any of the changes that come from increased insolation (changes in evaporation, thunderstorm numbers, outgoing long-wave radiation, changes in dust, etc.). These are the details of how the earth responds to hold the temperature down, but do not figure into the sensitivity.
I am basing it on two things. 1) Top of atmosphere (TOA) changes in insolation, and 2) surface air temperature (HadCRUT3 absolute temperatures, available here, under Data for Downloading, Absolute in the middle of the page. As above, the height of the tropopause is one of the variables in how the earth responds to the increase in insolation, so I do not base my calculations on that.
NickB. (20:38:04)
Where’s your neck of the woods?
O/T – apologies:
1 March: UK Times: Ben Webster: Green fuels cause more harm than fossil fuels, according to report
Using fossil fuel in vehicles is better for the environment than so-called green fuels made from crops, according to a government study seen by The Times…
http://www.timesonline.co.uk/tol/news/environment/article7044708.ece
26 Feb: WaPo: Sunil Sharan: The green jobs myth
For the purpose of creating jobs, then, a “clean-energy economy” will not offer a panacea. This does not necessarily mean that America should not become green to alleviate climate change, to kick its addiction to foreign oil or to use energy sources more efficiently. But those who take great pains to tout the “job-creation potential” of the green space might just end up inducing labor pains all around.
(The writer, a director of the Smart Grid Initiative at GE from 2008 to 2009, has worked in the clean-energy industry for a decade)
http://www.washingtonpost.com/wp-dyn/content/article/2010/02/25/AR2010022503945.html
Willis Eschenbach (18:32:21) Willis, what I am getting at is the data from the ‘SOURCE’, has the chart I linked to above. It is apparently modeled solar radiation shown as expected photovoltaic (PV) output, and models the output here in western Colorado to be 5.5-6.0 KW average daily output annually. I happen to know from my system the reality is 4.2 KW, and that matches expectations of the installer. The model is 36.9Δ% over reality. Therefore, I have to wonder on what assumptions all of the materials shown that wiki page are based. Secondly, if they do over estimate the solar energy in their models, does that lower your estimate of climate sensitivity?
I realize your chart is latitude vs. time-of-year, and I’m looking at the average for my latitude for any given day, ie. the average daily value of a horizontal line drawn across your chart for a given latitude. I wondered if their values are from the same modeling as the PV chart and are also too high.
have you considered that the particulates or aerosols might be introduced, not into the Earth’s atmosphere, but between the sun and the Earth’s orbit, as a feature of the solar system ingesting massive clouds of interstellar dust and fine ices, that decrease the total solar energy reaching the Earth for a longer time. Given that it takes the solar wind more time to flush out the intruding interstellar clouds, thus giving the fairly rapid onset and gradual release from the glacial epochs?
Why does it always have to be a local problem?
Mr. Eschenbach:
From: Thermostat Hypothesis
Good paper. I admire the smooth flow of your words and initially concur with the points you made, to say absolutely may take some time for it all to sink in.
Would you like to know of a one percent or so “as-yet unrecognized mechanism” that makes your conjecture of high-altitude radiation between the tropics and poles even more concrete? My guess is few would ever know of it and I have never heard it mentioned in climate science to date. You may accept it or reject it as you see fit, just want to make sure you read it.
TA (16:47:03)
Yes, accumulation of heat and other long term changes are indeed possible. But in the Southern Hemisphere, a change of 188 W/m2 in insolation (forcing) leads to a change of 2°C in temperature.
The IPCC, on the other hand, says that a change of 2.5 W/m2 of forcing leads to a change of 2°C in temperature …
So even if my numbers are out by an order of magnitude, which seems quite unlikely, the IPCC numbers are still way off. Even assuming that my numbers are wrong by an order of magnitude, you’d still need CO2 to rise to 3,900 ppmv (from their current 385 ppmv) to result in a 2°C temperature change …
Willis Eschenbach — OK, then you’ll have to propose your own. As I said, I don’t know the answer to the question, and have only posted possibilities.
Comet or asteroid strike in a more remote part of the world. Happens all the time; almost impossible to detect 300-800 years hence. A recent strike I read about was near Java or Borneo or something; had it hit a city, it would have wiped it out. Anyway, hit the right spot with enough force, and changes in ocean currents, slight increase in volcanism due to hitting a fault etc. could have a great deal of effect not necessarily localised for quite some time. There were how many years of cooling due to Krakatoa alone?
I’m not sure you need to postulate *anything* to explain the LIA.