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.
Willis, you might like to check out some work by Stephen Schwartz related to this topic. I think some of his wokrs supports your model.
Schwartz et al. Influence of anthropogenic aerosol on cloud optical depth and albedo PNAS, 2002 v. 99: 4, 1789
Schwartz S. E. Heat capacity, time constant, and sensitivity of Earth’s climate system. J. Geophys. Res.,5 112, D24S05 (2007).
Stephen E. Schwartz, Response to Comments on “Heat capacity, time constant, and sensitivity of Earth’s climate system”, Atmospheric Science Division, Brookhaven National Laboratory. URL: http://www.ecd.bnl.gov/steve/pubs.html#top
Seen this from Gore (scare tactics again)
http://www.nytimes.com/2010/02/28/opinion/28gore.html?pagewanted=1
We Can’t Wish Away Climate Change
February 27, 2010
Willis thank you for a post that even makes an untrained high school graduate (barely) understand what you are trying to say. This is why I read this blog because for the most part people here are patient with us (the unwashed masses) and that makes me feel that maybe there is hope that those in the ivory towers will get locked in and never be able to come out again.
paulID (21:25:36) :
And it’s people like you that make it clear to me that the time spent here is not a waste. Thanks for just commenting, yeah Willis’s paper stimulates the mind doesn’t it.
Sorry Willis,
That is not an appropriate formula for sensitivity . You need to calculate the amount of radiation out due to the change in temperature, so you must subtract the amount abosrbed, or you get nonsense.
You have chosen to investigate a cyclic forcing so you must pay attention to admittances. You simply must or you get bizarre results. The admittance into the ocean is in parallel to and much larger than the admittance into space. Unless you subtract it from the total admittance you are off by between one and two orders of magnitude over the oceans, and smaller but significant amount over the land masses due to thermal inertia alone.
Also the motion of the atmosphere drags low seasonal amplitudes from the ocean to the land. Only in a few remote landlocked spots is this minimised. Try your calculations for the areas with the highest seasonal range, like parts of Mongolia and Estern Siberia where the amplitudes are around and greater than +/- 30C. Even there you must take account of admittance. For even in such places there is a seasonal lag between peak insolation and peak temperature.
Regarding the tropics, if you are on the equator there are two peaks in insolation, spring and autumn, summer and winter have lower insolation, look at your graphic. This effect diminishes as one approaches mid latitudes and then reverses towards the poles.
There is a sizable six month component, and higher components, at the poles, think about it. The pattern of insolation is not exactly sinusoidal is it. This second and these higher order components are associated with higher admittances.
You have come up with some numbers but you do not seem to have allowed for surface admittance at any point and it is a dominating factor, along with the transference of thermal mass, and associated heat, by atmospheric motion and ocean currents.
These motions tend to reduce the seasonal range over the continental land masses as they pick up low thermal amplitudes, in the case of the atmosphere as it passes over the oceans, and in the case of the oceans as the gyres pass through their low amplitude legs, and they transfer these low amplitudes to the land and the higher latitude oceans respectively. On the way they pick up the higher continental amplitude which they dump back into the oceans in the case of the atmosphere, or transfer towards the equator in the case of the gyres. Plus of course there are the meridonal fluxes.
I see that you note three reasons why you think the ocean is not a major player in this and I am afraid that you are misled. The seasonal cyclic flux component into the oceans is far greater than the seasonal flux component into space. You can see that the temperature amplitude is low over the oceans, but why think that this is due to an ultra high thermal admittance into space when you have a huge thermal admittance all around you in the ocean itself.
Alex
I don’t think it is reasonable to do these calculations per hemisphere. In the tropics, solar insolation varies very little and neither does temperature. At higher latitudes, solar insolation varies a lot and so does temperature.
Some parts of Siberia vary by 70-80C between winter and summer. The oceans don’t vary very much because of their large heat capacity. Three months of summer isn’t long enough to make significant variations in deep ocean temperature.
There are a lot of different factors being munged to together in the sensitivity calculation. We know that changes in solar output of one percent have a significant impact on temperature, so it is not unreasonable to expect that climate is much more sensitive than what is being represented in these calculations.
need CO2 to rise to 3,900 ppmv (from their current 385 ppmv) to result in a 2°C temperature change
This may indeed be accurate!
TX for the post.
Tim L
Willis. You say “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.”
This allows you to ascribe all of the observed temperature change to the change in TOA insolation.
There is a danger here, and it is one that the IPCC fell prey to (rather willingly!). When looking at possible causes of temperature change other than CO2, the IPCC either eliminated them (eg. Svensmark’s theory was dismissed because it didn’t match data after ?1995), or included them at an unjustifiably low level (eg. solar variation, where they ignored empirical data that the solar cycle had a larger effect than could be explained by insolation changes), or counted them as a CO2 feedback (eg. water vapour and clouds), Consequently, they felt able to claim that virtually all of the observed temperature change was caused by CO2, and coded their computer models accordingly (look for “constrained by observation” in the IPCC Report).
Thus the IPCC have no provision for there being any significant influence on temperature that is independent of CO2.
Coming back to your paper : By assuming that all factors such as clouds, water vapour and ice coverage are insolation feedbacks, you have allowed yourself to ascribe all observed temperature changes to insolation changes. If some of these factors are in fact independent of insolation to any significant extent, then you have an invalid assumption.
For example, if some changes in cloud cover are not a response to insolation changes, but are a response to something else (Galactic Cosmic Rays for example), then you cannot assume that all observed temperature changes are caused by insolation changes, In this particular example, there is a strong relationship between GCRs and solar activity, so you may just be OK, but is the GCR relationship specifically to insolation or is it to a different solar activity?
Incidentally, you could I think eliminate this as a possible problem by conducting your study over a period of many years, rather than just one (“a year-long experiment such as the one I have done”).
—–
There is another question which I haven’t thought through : Your calculations of sensitivity appear to be based on short timescales (less than 1 year). The IPCC works on “equilibrium climate sensitivity”, and if I understand them correctly it may take several decades for equilibrium to be reached. Are you comparing like with like?
In other words, when you use the temperature change over a season, is it representative of the temperature change that would result if that season’s insolation forcing were to continue for several decades?
Graeme W (17:55:14) – you said:
“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?”
There is a theory, currently under study at CERN (“Cloud” experiment) that changing magnetic flux between sun and earth, changes the rate of cosmic rays entering the atmosphere, which in turn changes the rate of cloud cover development.
If correct, that explains why the climate changes over time.
Physicists such as Ken McKracken, are making great strides in understanding these mechanisms.
Ken believes current trends suggest that it is quite likely that the earth is entering a significantly cooler period.
I should have added that Willis’ theory meshes very well with the above.
The IPCC do not claim 3 C from 3.7 W/m2. The 3C is after feedbacks. 3.7 from CO2 + 3.7 from increased water vapor + 3.7 from slow feedbacks, roughly.
Anyway, all you have shown is that it takes a lot of energy to increase the temperature of water (and even more to melt ice and snow).
Willis, I suspect you might be interested in this analysis which also suggests a much lower climate sensitivity:
http://www.palisad.com/co2/eb/eb.html
Hi Willis,
I have two objections:
1) A hemisphere is an open system with two interfaces, one to the sky which is of interest for calculating sensitivity but the other interface is to the opposite hemisphere and is neglected in your discussion. A lot of heat flows across the equator each six months.
2) The “summer thermal solstice” (here at 35 degrees south in Sydney Aust) is 21 Jan, which is quite some time after the insolation maximum. This and the winter “thermal solstice” are the only times that insolation and heat loss are at equilibrium. (neglecting heat flow to other hemisphere in point 1) So you can’t use the whole summer temperature average in your calculation but should restrict it to the temp and insolation on the single date.
Willis, I just luuuuuurve your posts.
But I have a question. The geometry of insolation. Have you included a formula that calculates the integral of insolation throughout each day for each latitude, starting from a horizontal sun at dawn, rising to a higher sun at midday? Clearly, insolation is not just a multiple of length-of-day, and varies from low polar light to high tropical light; the loss due to low sun is most apparent at polar latitudes.
Thanks.
John Ritson (23:30:32) :
“So you can’t use the whole summer temperature average in your calculation but should restrict it to the temp and insolation on the single date.”
That wouldn’t help much.
“The Gulf Stream transports about 1.4 petawatts of heat, equivalent to 100 times the world energy demand”, to name one.
Willis, I think you’ve only calculated the climate sensitivity under the atmospheric conditions of that year. Changing conditions, for instance due to the heat accumulating in the ocean might give different results. It might be interesting to look at an El Nino year and a La Nina year and see what difference might occur with different conditions.
Hi Willis,
I have been looking at the frequency response of climate sensitivity, and the observations show evidence for a low pas filter response: i.e. low climate sensitivity for annual cycles and increasing climate sensitivity for longer cycles. IMHO the IPCC modeled estimates have a warm bias.
Below is a graph where observed and modeled climate sensitivities are plotted relative to logarithmic cycle period on the x-axis. The blue line was a first crude estimate.
http://members.casema.nl/errenwijlens/co2/Climate_sensitivity_period.gif
http://members.casema.nl/errenwijlens/co2/howmuch.htm
Willis
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.
Thanks for that one sentence summary of “(3×2’s) problem with CO2 as a primary driver of climate”. Wish I could have put it better myself.
Those bringing soot or whatever to the party really need to step back for a moment and look at the numbers. 1.4 billion cubic km of water wins every time.
is climate electric?
nice one willis
I have calculated 0.2 deg C for surface, mid-northern altitude bellow 50N. We have difference of ~20C between January and July and from the insolation chart, summer-winter difference in insolation is 350W/m2.
My objection is, the CO2 “forcing” is present all the time, while Sun insolation changes during the year. Had the polar summer last 10 years in a row, temperature would surely rise there, until some kind of balance would be restored? Also our mid-latitudes receive more sun energy in summer than tropics, but since it is just for a limited time (two months), we will not reach the tropic climate which would otherwise happen. The equilibrium can not establish itself.
Mike Jonas (22:53:47) :
There is another question which I haven’t thought through : Your calculations of sensitivity appear to be based on short timescales (less than 1 year). The IPCC works on “equilibrium climate sensitivity”, and if I understand them correctly it may take several decades for equilibrium to be reached. Are you comparing like with like?
In other words, when you use the temperature change over a season, is it representative of the temperature change that would result if that season’s insolation forcing were to continue for several decades?
We are back to “heat in the pipeline”, something that nobody seems able to pinpoint convincingly.
“Lon Hocker (18:21:30) :
Holey moley! You just found the missing link!
You might remember Beenstock’s paper (http://wattsupwiththat.com/2010/02/14/new-paper-on/), or perhaps my writeup (http://www.2bc3.com/warming.html) where we see that the temperature rise seems to be related to the rate of increase of CO2, not the absolute amount of CO2. Neither of us were aware of your earlier paper showing the earth’s temperature governor, and so we could come up with no explanation for the results we found.”
I was aware of it all the time, that’s why i had no problems swallowing the solution by Beenstock and Reingewertz. Had i known you didn’t know i would have told you… i had read Willis’ hypothesis before.
Re: John Ritson (Feb 28 23:30), says
“A hemisphere is an open system with two interfaces, one to the sky which is of interest for calculating sensitivity but the other interface is to the opposite hemisphere and is neglected in your discussion. A lot of heat flows across the equator each six months.”
I’d like to know your source for this assertion. George White, in his post I linked to earlier (http://www.palisad.com/co2/eb/eb.html), says
“A common explanation for why hemispheric asymmetry doesn’t matter is that an energy flux flows between hemispheres to equalize the system. This is contradicted by examining ocean circulation currents and weather circulation patterns. The hemispheric specific flows in the oceans and atmosphere run parallel to each other at the equator. The satellite data show very little seasonal temperature variability across a 30° slice of latitude centered on the equator. This is important because an energy flux must be accompanied by a proportional temperature differential. Thermodynamics tells us that energy flows from warm bodies to cold bodies. The warmest part of the Earth is the equator, which means that energy flows from the equator to the poles, but not across the equator, except due to some tropical weather systems and some minor coupling where Northern and Southern ocean currents run parallel to equatorial currents. This weak coupling is often considered part of the Thermohaline circulation. The result is that the 2 hemispheres are only weakly thermodynamically coupled and respond to change mostly independent of each other.”
Gary Palmgren (20:18:42) :
Your view equals mine.
It’s funny how much the AGW hypothesis blinds people in the warmistocracy; if we can see it they should be able to as well.
Long term insolation variations got a brief mention above.
Useful references on this are as follows:
Berger, A.; Loutre, M.F. 1991. Insolation values for the climate of the last 10 million years. Quaternary Science Reviews 10: 297-317.
Berger, A. 1992. Orbital Variations and Insolation Database. IGBP PAGES/World Data Centre-A for Paleoclimatology Data Contribution Series #92-007. NOAA/NGDC Paleoclimatology Program, Boulder, Co, USA.
These refs show the change in insolation at various latitudes each 1000 years going back 100’s of thousands of years.