Drying The Sky

Guest Post by Willis Eschenbach

Eleven years ago I published a post here on Watts Up With That entitled “The Thermostat Hypothesis“. About a year after the post, the journal Energy and Environment published my rewrite of the post entitled “THE THUNDERSTORM THERMOSTAT HYPOTHESIS: HOW CLOUDS AND THUNDERSTORMS CONTROL THE EARTH’S TEMPERATURE“.

When I started studying the climate, what I found surprising was not the warming. For me, the oddity was how stable the temperature of the earth has been. The system is ruled by nothing more substantial than wind, wave, and cloud. All of these are changing on both long and short time cycles all of the time. In addition, the surface temperature is running some thirty degrees C or more warmer than would be expected given the strength of the sun.

Despite that, the earth’s temperature has stayed in a surprisingly narrow range. The HadCRUT global surface temperature shows that the range of the temperature trend was 13.9°C ± 0.3°C over the entire 20th Century. This represents a temperature variation of ±0.1% during a hundred years. That stability was the curiosity of curiosities for me, because to me that temperature stability was clear evidence of some kind of a strong thermoregulatory system. But where and what was the regulating mechanism?

The short version of my hypothesis is that a variety of emergent phenomena operate in an overlapping fashion to keep the earth’s temperature stable beyond expectations. These phenomena include tropical cumulus clouds, thunderstorms, dust devils, squall lines, tornadoes, the La Nina pump moving warm water to the Poles, tropical cyclones, and the Julian-Madden, Pacific Decadal and North Atlantic Oscillations. In addition, I’ve adduced a large body of evidence supporting my hypothesis.

So I was interested to see Judith Curry, in her marvelous weekly post entitled “Week in review – science edition“, had linked to a paper I’d never seen. It’s a paper from 2010 by Marat F. Khairoutdinov and Kerry A. Emanuel (hereinafter K&E) entitled AGGREGATED CONVECTION AND THE REGULATION OF TROPICAL CLIMATE, available here. Inter alia they say:

Moist convection in the Earth’s atmosphere is mostly composed of relatively small convective clouds that are typically a few kilometers in horizontal dimension (Byers and Braham, 1948, Malkus, 1954). These often merge into bigger clusters of ~10 km in horizontal dimension, such as air-mass showers. More rarely, under special circumstances, moist convection is organized on even larger scales; this includes squall lines (e.g. Houze, 1977), mesoscale convective complexes, (e.g. Maddox, 1980), and tropical cyclones.

One of the robust characteristics of self-aggregation is the rather dramatic change in the mean state that accompanies it. In particular, in all non-rotating experiments (Bretherton et al., 2005) and an experiment on an f-plane (Nolan et al., 2007), self-aggregation leads to dramatic drying of the domain-averaged environment above the boundary layer. This appears to be the result of more efficient precipitation within the convective clump as more of the condensed water falls out as rain and less is detrained to the environment, per unit updraft mass flux. Such dramatic drying would reduce the greenhouse effect associated with the water vapor, and thus, would lead to cooling of the SST, which in turn may disaggregate convection. This would re-moisten the atmosphere, increasing the water-vapor greenhouse effect, and, consequently, warming the system. So, as in self-organized criticality (SOC), the tropical state would be attracted to the transition critical state between the aggregated and disaggregated states.

Let me point out a few things about their most interesting study. First, they are clear that a strong effect of the aggregated thunderstorms is to regulate the tropical temperature … just as I’ve been saying for years.

Unfortunately, their study is model-based. This is always frustrating to me because there is no way to check either the quality of their models or how many runs ended up on the cutting room floor …

However, given that shortcoming, their study points to something I noted in my original post—not just aggregated thunderstorms but also individual thunderstorms dry out the air in between them. This has two big cooling effects on the surface. 

First, the dry descending air allows for increased evaporation from the surface, because the dry air can pick up more moisture from the surface. This increased evaporation cools the surface.

In addition to the increased evaporation, the effect they discussed is that the dryer air descending around the thunderstorms reduces the amount of the world’s main greenhouse gas, water vapor, that is between the surface and outer space. This allows the surface to radiate more freely to space, which also tends to cool the surface.

In their summary they say:

Idealized simulations of radiative-convective equilibrium suggest that the tropical atmosphere may have at least two stable equilibrium states or phases, one is convection that is random in time and space, and the second is the spontaneously aggregated convection. In this study, we have demonstrated using a simplified and full-physics cloud-system-resolving models that there is an abrupt phase transition between these two equilibrium states depending on the surface temperature, with higher SST being conducive to the aggregation. A significant drying of the free troposphere and consequent reduction of the greenhouse effect accompany self-aggregation; thus, the sea-surface temperature in the aggregated state tends to fall until convection is forced to disaggregate.

So, big credit to them for noticing the thermostatic effect in the tropics. However, their look is tightly focused. They have looked only at one cooling mechanism. In addition, they have only looked at two of what are at least four of what they call stable equilibrium states or phases. However, again to their credit they’ve said “at least” two stable states, acknowledging the existence of others.

Since Khairoutdinov and Emanuel had demonstrated using models that dry air increased with increasing aggregated thunderstorms, I thought I’d take a look at, you know … observations. Data. Crazy, I know, since so much attention is paid to models, but I’ve been a computer programmer far too long to put much faith in models.


Let me start by saying that they are looking at the third and fourth stable equilibrium states in the entire spectrum of the daily tropical thermally-driven threshold-based atmospheric response to increasing surface temperature. Each of these steps involves self-organized criticality. 

In the tropics, by dawn, particularly over the ocean, the night-time atmosphere is generally stable and thermally stratified, with clear skies at dawn.

The first step is when the solar warming of the surface warms the air above it enough to initiate the stable equilibrium state called Rayleigh-Benard convection. As is common with such self-organized transitions, once the critical transition temperature is exceeded, the change between states is rapid. 

Once Rayleigh-Benard circulation is established, areas of ascending air are interspersed with areas of descending air. The areas of rising air, often called “thermals”, transfer surface heat and surface water vapor upwards. This cools the surface directly through conduction, because the air traveling across the surface picks up heat from the surface. The R-B circulation also increases thermal radiation to space from the upward movement of the warm air above the lowest atmosphere, which contains the greatest amount of greenhouse gases. 

Finally, the R-B circulation increases evaporation by moving the surface moisture upwards and mixing some of it into the lowest part of the troposphere.  This transition to R-B circulation is generally invisible, although the onset of daily overturning can sometimes be felt in the wind.

The second transition is again temperature-based. It occurs when the surface temperature is large enough to drive the Rayleigh-Benard circulation higher into the troposphere. In the tropics, this transition typically happens in the late morning. When the water vapor in the ascending columns of the Rayleigh-Bernard circulation is moved upwards to the “LCL”, the “lifting condensation level” where water vapor condenses, at that altitude cumulus clouds form. The water vapor in the air condenses into the familiar puffy cotton-ball cumulus clouds. Each individual cumulus cloud group sits like a flag marking an ascending part of the Rayleigh-Benard circulation shown above. 

Again, the transition is rapid. In the space of about a half-hour, the entire tropical atmospheric horizon to horizon can go from clear air to a fully developed cumulus field. And again, the transition is temperature-based. Below a certain temperature, there are hardly any cumulus clouds at all. Above that temperature, suddenly there are lots of cumulus clouds.

The third transition occurs when a somewhat higher temperature threshold is exceeded. The third stage of development is when individual cumulus clouds self-aggregate into scattered cumulonimbus. They build tall cloud towers, and the rain starts.

After this transition to the thunderstorm state, large areas of descending dry air form around each thunderstorm. This is the return path of the air that was first stripped of water in the base of the thunderstorm. When the water vapor condenses it gives up heat. The heated air then moves up the thunderstorm tower, emerges at the top, and descends as dry air in the areas around the thunderstorm. 

This stage, of active thunderstorms, is well illustrated in the most entrancing simulation shown below. The colored layer added at one minute twenty seconds shows the temperature of that layer, with dark blue being coldest and red/orange being warmest.

The fourth and final transition occurs only in certain conditions at the highest transition temperature, when individual thunderstorms self-aggregate into squall lines and supercells, medium-scale convective complexes, and tropical cyclones. This is the only one of the four stable equilibrium states studied by Khairoutdinov and Emanuel. As with the other transitions, they point out that it is associated with a transition temperature. Like the thunderstorm regime, areas of descending dry air form around the aggregated phenomena. Here’s a photo of a single squall line from space.

It is worth noting that each of these succeeding stages exhibits an increase in the rate at which the surface loses heat. With each transition, the rate of surface heat loss increases from a variety of causes. The cause that is discussed by K&E, increased radiation to space through drier air, is only one among many.

The first transition, from quiescent stratified night-time atmosphere to Rayleigh-Benard circulation, increases surface heat loss to the atmosphere through conduction and convection of both latent and sensible heat. It encourages atmospheric loss to space by moving the surface heat up above the lowest atmospheric levels with their denser concentration of the greenhouse gases, mostly water vapor and CO2. It mixes surface heat and surface water vapor upwards. Because water vapor is lighter than air, the ascending areas are moister and the descending areas are dryer in the R-B circulation.

The second transition, to the cumulus field, adds two new methods of cooling the surface. First, energy is moved from the surface aloft in the form of latent heat. This heat is released when the rising columns of air condense into clouds. The sun then re-evaporates the water from the upper surface of the clouds, and the water vapor mixes upwards. This moves the surface heat well up into the lower troposphere.

The cumulus field also cools the surface by reflecting sunlight back to space. This is a very large change in the energy balance, on the order of a couple of hundred watts per square metre or so. The timing and density of the emergence of the cumulus field is one of the major thermal regulation mechanisms. How strong is this regulatory action? Here’s a typical day’s available solar energy, measured at ten-minute intervals at a TAO buoy in the Equatorial Pacific Ocean.

The deep notch in the available solar energy from clouds covering the sun at around 11:30 AM in the graphic above is quite typical of the drop when clouds cover the sun. On this day it lasted about half an hour. It reduced the available solar energy flux by about six watts per square metre averaged over that 24 hour period.

By comparison, a theoretical doubling of CO2 from the present, which is highly unlikely to happen, would add a flux of about 3.7 watts per square metre during that 24 hour period.

So in that area, that one cloud would be more than enough to cancel out even a doubling of CO2 for that day … and that is just one of the many ways the surface is being cooled by emergent phenomena.

The third transition, from developed cumulus field to scattered thunderstorms, adds the whole range of new surface cooling methods that I list in the endnotes. And unlike the first two transitions, thunderstorms can actually cool the surface to a temperature below the temperature needed to initiate the thunderstorms. This allows thunderstorms to maintain surface temperatures. When any location gets hot a thunderstorm forms and cools the surface back down, not just to where it started, but down below the onset temperature. This “overshoot” is the signature of a governor as opposed to a simple linear or similar feedback. Simple feedback can only reduce a warming tendency. A governor, on the other hand, can turn warming into cooling.

In the fourth transition, the transition to the larger self-aggregated phenomena like squall lines, supercells, and the like, no new surface cooling methods are added. What happens instead is that the previous methods move to a new level of efficiency. For example, thunderstorms self-organize into squall lines as shown in the photo above. 

Instead of individual areas of descending air around each individual thunderstorm, in a thermally-driven squall line you get long rolls of dry descending air along the flanks of the squall line. Because the carpet-roll-type circulation is streamlined, with the air smoothly rolling in a long tube, the squall line moves more energy from the surface to the upper troposphere than would be moved by the same number of individual thunderstorms.

To summarize the discussion so far:

There are four distinct successive emergent transitions from a quiescent stratified atmosphere to fully developed squall lines. Each is the result of self-organized criticality. Each one is a separate emergent phenomenon, coming into existence, persisting for some longer or shorter time, and then disappearing. In order, the transitions and the new emergent phenomena are:

  • Still air to Rayleigh-Benard circulation
  • Rayleigh-Benard circulation to cumulus field.
  • Cumulus field to scattered thunderstorms
  • Scattered thunderstorms to aggregated thunderstorms.

Each transition removes more energy from the surface to the atmosphere and thus eventually from the system.

Khairoutdinov and Emanuel discuss drying of descending air in only one of the states, the fourth one where thunderstorms aggregate. They are correct. However, this does not begin at the fourth stage. All the stages dry the descending air. And after each succeeding transition, the air becomes dryer and dryer.

I’ve demonstrated the close dependence of thunderstorms and “aggregated” thunderstorms on the surface temperature. I made up a movie showing this a while back using the CERES data, hang on … OK, here it is. I am using the extent of deep convection as measured by the cloud top heights as a measure of the strength of the thunderstorms and aggregates.

In the movie, you can see the thunderstorms and aggregated thunderstorms (color) following the warm water (gray lines) around the Pacific throughout the year. 

And if we take a scatterplot of average cloud top altitude versus sea surface temperature, we find the following relationship: 

Just as we saw in the movie above, when the sea surface temperature goes over about 26°C thunderstorms explode vertically, getting taller and taller. This is clear support for the idea that the transition between states is temperature-threshold based.

With all of that as prologue, let me move to the question of the descending dry air between the thunderstorms. I realized that we actually have some very good information about the amount of water in the air. This is data from the string of what are called the TAO/TRITON buoys and other moored buoys that stretch on both sides of the Equator around the world. Here are their locations.

Let me begin with another look at rainfall and temperature. Here’s a scatterplot of the sea surface temperature versus the rainfall in the equatorial Pacific area shown by the yellow box above (130°E – 90°W, 10°N/S). The blue dots below show results from the TAO buoys in the yellow box. The red dots show gridcell results from the Tropical Rainfall Measuring Mission (TRMM) satellite rainfall data and Reynolds OI sea surface temperatures.

Man, I do love it when several totally independent datasets agree so well. In the graph above the blue dots are co-located measurements of average rainfall and sea surface temperature at individual TAO/Triton buoys. The red dots are 1° latitude by 1° longitude averages of Reynolds OI Sea Surface Temperatures, and Tropical Rainfall Measuring Mission (TRMM) satellite-based rainfall data. And in both datasets, we see once again that thunderstorms start forming in numbers only when sea surface temperatures get above about 26°C.

It’s also interesting that once the sea surface temperature gets into the upper-temperature range, there are no dry areas. Every place gets at least a certain minimum amount of rain. Not only that, but the minimum amount of annual rainfall increases smoothly and exponentially as the average sea surface temperature goes up.

Why is it so important that this threshold is temperature based? It’s important for what it is NOT. It is not forcing based. In other words, the great global thunderstorm-based air-conditioning and refrigeration system kicks in at about 26°C, no matter what the forcing is doing. No matter what the CO2 is doing. No matter what the volcanoes are doing. The regime shift from puffy white cumulus clouds to scattered thunderstorm towers kicks in when the temperature passes a temperature threshold, and not before, regardless of what CO2 does.

And this, in turn, means that these successive regime shifts, first to Rayleigh-Benard circulation, then to the cumulus field, then to scattered thunderstorms, and finally to aggregated thunderstorms, are functioning in a host of different ways to regulate and cap the surface temperature.

And finally, by a fairly circuitous but interesting route, we’ve arrived back at the question of the drying of the air in between the thunderstorms and thunderstorm aggregations.

There are eight TAO buoys that are directly on the Equator across the Pacific. It’s an interesting group because they all get identical sunshine. Despite getting identical solar energy, there is a temperature gradient from Central America across to Asia, with the Asian end at about 29°C and the South American end at about 24°C. So looking at these eight buoys gives us a look at how some phenomena vary by temperature. 

Using the temperature and the relative humidity measurements from these buoys, I calculated the absolute humidity for each of them. This is the amount of water that is present per cubic metre of air. That number is important because the absorption of long-wave radiation by water vapor varies proportionally to the absolute humidity, not the relative humidity. Less absolute humidity means more surface heat loss by long-wave radiation to space.

These observations from the buoys are done every ten minutes. This allows me to calculate what an average day’s variations look like. To understand the daily variations, I aligned them at the morning minimums. Here are the records of those eight TAO buoys that are directly on the Equator.

In this graph, note that the warmer that the sea surface temperatures are, the smaller the 10 AM peak, and the more the afternoon absolute humidity drops from the 10 AM peak.

This is because as the thunderstorms form and increase the local area moisture is concentrated in the small area in and under the thunderstorms, with descending dry air between the thunderstorms making up the bulk of the lower troposphere. And in areas with warmer sea surface temperatures, shown in red above, clouds and thunderstorms form earlier, are denser, and at times form even larger aggregations of thunderstorms.

Now, what I’ve shown above are long term full-dataset averages. So it’s tempting to think “well, thunderstorms only happen where the average temperature is over 26°C”. But thunderstorms are not touched by averages. These temperature-regulating phenomena can appear, persist, and disappear at any time of day. All that matters are the instantaneous conditions. Whenever the tropical ocean gets warm enough, regardless of the longer-term averages for that location, you are likely to see thunderstorms form. All the averages mean is that the surface gets sufficiently hot to create thunderstorms on more or fewer days of the year.

My conclusions?

K&E were right about the drying power of aggregated thunderstorms. 

It is also true that individual thunderstorms, as well as cumulus clouds and Rayleigh-Benard circulation, dry out the descending air.

This lower level of water vapor cools the surface by increasing radiation loss to space and by increasing evaporation.

This is only one of the host of ways that cumulus clouds and thunderstorms keep the tropics from overheating

Rayleigh-Benard circulation, cumulus fields, scattered thunderstorms, and aggregated thunderstorms are all emergent phenomena. They emerge wherever there is sufficient surface heat, meaning when the temperature exceeds some local threshold. Each succeeding state, in turn, starts removing more heat from the surface. This is an extremely efficient temperature regulating system because they emerge only as and where there are local concentrations of surface heat.

Finally, I want to emphasize one of K&E’s interesting claims:

Such dramatic drying would reduce the greenhouse effect associated with the water vapor, and thus, would lead to cooling of the SST, which in turn may disaggregate convection. This would re-moisten the atmosphere, increasing the water-vapor greenhouse effect, and, consequently, warming the system. So, as in self-organized criticality (SOC), the tropical state would be attracted to the transition critical state between the aggregated and disaggregated states.

In other words, all of these phenomena act to stabilize the temperature.

Here, sunshine. Life is good. My very best wishes to all.


My Usual Request: When you comment please quote the exact words that you are referring to, so we can all understand your subject.


K&E are looking just at increased radiation through dryer air. This is only one of the many ways that thunderstorms cool the surface. Here’s a more complete list.

• Refrigeration-cycle cooling. A home refrigerator evaporates a working fluid in one location and condenses it in another location. This removes heat in the form of latent heat of evaporation/condensation. The thunderstorm uses the exact same cycle. For the thunderstorm the working fluid is water. Water evaporates at the surface and is carried aloft via the thunderstorm circulation. This, of course, removes surface heat in the form of latent heat. Then, just as in a domestic refrigeration cycle, the working fluid condenses at altitude in the thunderstorm base and falls back as a cold liquid to the surface.

• Self-generated evaporative cooling. Once the thunderstorm starts, it creates its own wind around the base. This self-generated wind increases evaporation in several ways, particularly over the ocean.

  • a) Evaporation rises linearly with wind speed. At a typical squall wind speed of 10 mps (20 knots), evaporation is about ten times higher than at “calm” conditions (conventionally taken as 1 mps).
  • b) The wind increases evaporation by creating spray and foam, and by blowing water off of trees and leaves. These greatly increase the evaporative surface area, because the total surface area of the millions of droplets is evaporating as well as the actual surface itself.
  • c) To a lesser extent, surface area is also increased by wind-created waves (a wavy surface has a larger evaporative area than a flat surface).
  • d) Wind created waves in turn greatly increase turbulence in the atmospheric boundary layer. This increases evaporation by mixing dry air down to the surface and moist air upwards.

• Wind-driven albedo increase. The white spray, foam, spindrift, changing angles of incidence, and white breaking wave tops greatly increase the albedo of the sea surface. This reduces the energy absorbed by the ocean.

• Cold rain and cold wind. As the moist air rises inside the thunderstorm’s heat pipe, water condenses and falls. Since the water is originating from condensing or freezing temperatures aloft, it cools the lower atmosphere it falls through, and it cools the surface when it hits. In addition, the falling rain entrains a cold wind. This cold wind blows radially outwards from the center of the falling rain, cooling the surrounding area.

• Increased reflective area. White fluffy cumulus clouds are not tall, so basically they only reflect from the tops. On the other hand, the vertical pipe of the thunderstorm reflects sunlight along its entire length. This means that thunderstorms shade an area of the ocean out of proportion to their footprint, particularly in the late afternoon.

• Modification of upper tropospheric ice crystal cloud amounts (Lindzen 2001, Spencer 2007). These clouds form from the tiny ice particles that come out of the smokestack of the thunderstorm heat engines. It appears that the regulation of these clouds has a large effect, as they are thought to warm (through IR absorption) more than they cool (through reflection).

• Enhanced night-time radiation. Unlike long-lived stratus clouds, cumulus and cumulonimbus often die out and vanish as the night cools, leading to the typically clear skies at dawn. This allows greatly increased nighttime surface radiative cooling to space.

• Delivery of dry air to the surface. The air being sucked from the surface and lifted to altitude is counterbalanced by a descending flow of replacement air emitted from the top of the thunderstorm. This descending air has had the majority of the water vapor stripped out of it inside the thunderstorm, so it is relatively dry. The dryer the air, the more moisture it can pick up for the next trip to the sky. This increases the evaporative cooling of the surface as well as allowing more radiative loss to space.

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January 7, 2020 2:15 pm

This is a great article by Willis Eschenbach on heat transfers within the atmosphere and explains a lot of observable actions of clouds especially in the tropics. It is a refreshing antidote to the endless Climate Change / Global Warming articles on the transfer of wealth within the Socialist atmosphere.

Stephen Richards
Reply to  Willis Eschenbach
January 8, 2020 12:59 am

always love reading your dissertations, willis. they are clear, detailed and thorough. thank you

Louis Hooffstetter
Reply to  Stephen Richards
January 10, 2020 7:13 am

I second this remark!

Also, K&E should have cited your previous work in their references. They effectively plagiarized your work without giving you credit.

Reply to  nicholas tesdorf
January 8, 2020 4:54 am

In other words, all of these phenomena act to stabilize the temperature. – article

Dagnabbit, Willis, you just smashed the biggest whine claimed by the Greenies!!! You’re gonna hurt their feewings!!!

I much prefer the real results from real-time data over models, because models are limited and the real world is not. Chaos factor is never taken into account with modeling – NEVER. Chaos factor also explains why, when I don’t have a camera with me, the most fascinating columns of air that look like nuclear bombs as they rise are never photographed by me. Duh!!!

Reply to  nicholas tesdorf
January 8, 2020 6:14 am

A master at work

January 7, 2020 2:18 pm

This is absolutely fascinating and a valuable contribution to climate science.

Reply to  Mike Smith
January 8, 2020 10:52 am

Valuable.. yes, possibly the MOST valuable.. “the cooling effect is independent of forcing”. That’s a big hello to CO2, aerosol alarmists. Dr. Lindzen used data to calibrate his Iris effect and that suggested a climate sensitivity of 0.7C. W.E. might up the ante to 0.5 C or smaller.

Mike Haseler (Scottish Sceptic)
January 7, 2020 2:41 pm

This looks to be what I described as a “hard stop”: a feature in the earth’s climate that creates massive negative feedbacks effectively stopping warming. The key to proving it is this “hardstop” is to show it exists at ~26C no matter what the climate is doing and not that it just happens to be 26C … for the moment.

I wrote to you several times about this but you did not reply. That in large part was why I’ve stopped working on climate.

Smart Rock
Reply to  Willis Eschenbach
January 7, 2020 7:41 pm

Great article, Willis. It not only provides a powerful argument against the CO2-as-control-knob hypothesis but explains why there has been warming in high latitudes in the post-1970s while temperatures in the equatorial region have done nothing.

Intuition tells me that the 26°C threshold and the 30°C absolute limit are fixed, and are defined by the physical properties of water and air. Those limits can’t change because … it just wouldn’t feel right. If it wasn’t late and I wasn’t tired, I might be able to articulate the thoughts behind that feeling. Or possibly not.

Changing salinity would probably vary those numbers by changing the partial pressure of water vapour in equilibrium with saline water, but it wouldn’t be by much within the range of normal ocean salinity.

Reply to  Smart Rock
January 8, 2020 5:05 am

You should probably do not say fixed. They are related to current air pressure. Theory is that atmospheric pressure is declining through eons, so this limit is changing with it.

Nick Werner
Reply to  Peter
January 8, 2020 1:06 pm

That’s interesting. I like Willis’ reasoning, and had just looked up ‘atmospheric pressure’ after one of my outside-the-GCM-black-box thoughts.

According to Wiki, average sea level pressure is 101.325 kPa. Let’s say that ten years ago it was also 101.325 kPa.

Then what “solid” evidence is there that there was a NET addition of greenhouse gases to the atmosphere over a decade from burning fossil fuels? However many gigatons of CO2 were added to the atmosphere would have displaced an equivalent weight of something that’s at least as abundant . Like water vapour… another greenhouse gas.

(And volume-wise that would be a twofer… two lighter GHG molecules eliminated for the price of one).

Reply to  Peter
January 10, 2020 4:07 am

Another of the boundary conditions would be the tendency of clouds to form from super-saturated water vapour. This is where the cosmic ray theory comes in, increasing the tendency for clouds to form when the sun’s magnetic influence is low. If true, it would explain why the Earth’s temperature seems to be tied to solar variability.

Erik Magnuson
Reply to  Smart Rock
January 8, 2020 9:56 pm

I played around with calculating the enthalpy of air and water vapor at 100% RH, and somewhere around 26C the change in enthalpy with temperature was driven more by the water vapor than air. Seems to me that the threshold temperature would increase with increasing sea level pressure. Note that 26C is the minimum SST to sustain a tropical cyclone.

Willis had an interesting posting a few days back on CERES data indicating that the change in temperature for 3.7W/m^2 increase in downwelling radiation was less than a black body radiator for temperatures greater than 0C and more than the black body radiator for temperatures less than 0C. This would explain why the temperature response appears to show a positive feedback during glacial periods, and a very strong negative response during the interglacial periods.

Reply to  Willis Eschenbach
January 7, 2020 10:00 pm

You are probably aware of these studies but, for others information, I will post them.

4 – McLean, J. (2014) – “Late Twentieth-Century Warming and Variations in Cloud Cover”, Atmospheric and Climate Sciences, October 2014, (available online free of charge at


Winter monsoons became stronger during geomagnetic reversal
Revealing the impact of cosmic rays on the Earth’s climate

July 3, 2019
Kobe University
New evidence suggests that high-energy particles from space known as galactic cosmic rays affect the Earth’s climate by increasing cloud cover, causing an ‘umbrella effect’.

Finnish study finds ‘practically no’ evidence for man-made climate change
12 Jul, 2019
Also, here.

A new paper published by researchers form the University of Turku in Finland suggests that even though observed changes in the climate are real, the effects of human activity on these changes are insignificant. The team suggests that the idea of man made climate change is a mere miscalculation or skewing the formulas by the Intergovernmental Panel on Climate Change (IPCC).
Jyrki Kauppinen and Pekka Malmi, from the Department of Physics and Astronomy, University of Turku, in their paper published on 29th June 2019 claim to prove that the “GCM-models used in IPCC report AR5 fail to calculate the influences of the low cloud cover changes on the global temperature. That is why those models give a very small natural temperature change leaving a very large change for the contribution of the green house gases in the observed temperature.”

The Thermostat Hypothesis


The Thermostat Hypothesis is that tropical clouds and thunderstorms actively regulate the temperature of the earth. This keeps the earth at a equilibrium temperature.
Several kinds of evidence are presented to establish and elucidate the Thermostat Hypothesis – historical temperature stability of the Earth, theoretical considerations, satellite photos, and a description of the equilibrium mechanism.
Clouds form and rain starts during a day near the equator.
Thermostat regulate the suns effect.
…Finally, the equilibrium variations may relate to the sun. The variation in magnetic and charged particle numbers may be large enough to make a difference. There are strong suggestions that cloud cover is influenced by the 22-year solar Hale magnetic cycle, and this 14-year record only covers part of a single Hale cycle.


The Thermostat Hypothesis


The Thermostat Hypothesis is that tropical clouds and thunderstorms actively regulate the temperature of the earth. This keeps the earth at a equilibrium temperature.
Several kinds of evidence are presented to establish and elucidate the Thermostat Hypothesis – historical temperature stability of the Earth, theoretical considerations, satellite photos, and a description of the equilibrium mechanism.
Clouds form and rain starts during a day near the equator.
Thermostat regulate the suns effect.
…Finally, the equilibrium variations may relate to the sun. The variation in magnetic and charged particle numbers may be large enough to make a difference. There are strong suggestions that cloud cover is influenced by the 22-year solar Hale magnetic cycle, and this 14-year record only covers part of a single Hale cycle.


Reply to  KcTaz
January 7, 2020 10:02 pm

Oops, sorry forthe replication. Not sure how I managed that other than I got distracted.

Mike Haseler (Scottish Sceptic)
Reply to  Willis Eschenbach
January 8, 2020 1:10 am

What I was suggesting was to compare an El Nino year like 2016 with non El Nino years. This would distinguish between two potential explanations: 1) that the effect was latitudinal and 2) that it was temperature based. (If latitudinal the “26” would change temperature as average global temp went up.)

If the temperature remained constant, then this would be strong evidence that we have a change in the climate that introduces a regime of strong negative feedbacks, and this explains both why the rapid ice-warming came to an abrupt end and also why each interglacial has been at approximatelyt he same temeprature (controlled by this “26C”).

It also explains why we can both have strong positive feedbacks for cooling/warming into/out of the glacial period, but still have a very stable regime in the interglacial period which prevents warming. It suggests the strong positive feedbacks are a combination of Ice-albedo effect and water vapour positive feedback (as in the atmosphere dries and that enhances cooling).

At the time I wrote, I was hoping to get help accessing the data for 2016, but unfortunately as there seemed no way to progress the subject, I’ve now started working on other things entirely unrelated to climate.

Jennifer Symonds
Reply to  Willis Eschenbach
January 9, 2020 5:08 am

How does geoengineering affect all this? ( I would imagine SAG &c might have an adverse affect0

January 7, 2020 2:44 pm

Willis, are your aggregated thunderstorms what causes or forms atmospheric rivers that we occasionally see stretching from Hawaii to the west coast of the US?

Reply to  Willis Eschenbach
January 7, 2020 5:15 pm

I’m pretty sure that the so called atmospheric rivers are a creation of the jet stream.

Reply to  MarkW
January 7, 2020 7:28 pm

The atmospheric river called the Pineapple Express seems to be related to the pumping action of a low pressure system positioned to the north, and high pressure system to the south. Air near the low pressure system is rushing towards the center in a counter clockwise spiral, the opposite with the high pressure system. This sets up a pumping action where air between the systems is pumped on both sides to form the atmospheric river.

On this day (oddly) in 2017 there was low off the Oregon coast and a high off the Baja coast. The river was running at 30 to 40 mph at the 5000 foot level and there was 40 kg of water vapor per square meter of ground surface and it rained a lot in California.

Reply to  MarkW
January 8, 2020 6:52 am

Atmospheric rivers are associated with Rossby waves, which are generated by planetary rotational (Coriolis) forces, to conserve potential vorticity. When zonal winds (east-west) are perturbed meridonally (north-south), Coriolis-induced rotation acts as a restoring force to limit the perturbation.

Rossby waves are responsible for a part of the meridional transports of momentum, energy and water vapor and they are thus an integrating part of the global circulation. Important to note that this circulation of the warm and cold air between the tropics and polar regions doesn’t _cause_ the Rossby waves, but is an _effect_ of these waves, which are caused by the rotation of the Earth.

They are _transverse waves_, that is the oscillation is perpendicular to the direction of travel, which is always from west to east. A parcel of air moving east is pushed to the right (southward) by the Coriolis effect, but this instability is offset by the need to conserve vorticity, which acts a restoring effect and eventually pushes the parcel northward again. This cycle repeats forever, creating a series of planetary waves which have always been there.

So these atmospheric rivers are typically located ahead of cold fronts pushed eastward by the leading edge of mid-latitude Rossby wave troughs.

January 7, 2020 2:46 pm

Excellent. It looks like you’ve put together the foundations of a new empirically based climate model Willis! Many thanks for your work.

Joe Born
January 7, 2020 2:55 pm

Bookmarked; added to my (lengthy) thermostat-hypothesis folder.

There also seems to be a connection to Richard Lindzen’s iris hypothesis. That, when it’s hotter, the precipitation gets more efficient, leaving less water vapor to be detrained into (the earth-warming) cirrus clouds and thereby providing negative feedback.

Ben Wouters
January 7, 2020 2:59 pm

• This is only one of the host of ways that cumulus clouds and thunderstorms keep the tropics from overheating

How do you envision the tropics to overheat? Tropics are mostly ocean, and a good day of sunshine in the tropics delivers some 25 MJ/m^2 to these oceans. Since the sun directly warms only the upper 5-10 m directly, this roughly enough energy to warm this column 1K. During the night this “stored” energy is lost again to the atmosphere/space.

Geoff Sherrington
January 7, 2020 3:06 pm

Great essay, will take several more reads to fully apreciate.
An immediate question, if I may? Regulating, governor systems typically have a set point that they strive to get back to. It can be set on mechanical systems and adjusted to suit the purpose. Like the weight of those revolving iron balls that move an adjustment sleeve up and down to hunt for a desired rotational velocity by a link to the throttle or steam pressure.
Question is, can we imagine a set point in this weather mechanism? You have often noted max SST of 27C, but what informs the mechanism that 27C has been reached? Intuitively, I look first for a physical mechanism like a phase change that is easy for the mind to envisage as having some needed properties. The concept of the weather comparing itself to this reference set point, then adjusting, is attractive by analogy to the mechancal feedback governor, but this might be false.
Any thoughts? Geoff S

Reply to  Geoff Sherrington
January 8, 2020 12:53 pm


If I’ve read your question right Willis has answered your question in previous postings on his governor theory, been to long since I’ve read them so trying to recite from memory will get things wrong. Reading through those should answer your question and probably bring up more. Bit surprised because normally he links all his previous articles to his current one but a it will just take a quick search on WUWT to turn up the articles.

Geoff Sherrington
Reply to  Darrin
January 8, 2020 2:48 pm

Was smply asking if the early off-the-cuff response had matured with further thought and time.
People claim the globe has warmed naturally since the Little Ice Age. I ask by what mechanism.
Willis and others write about clouds governing global temperatures – which I consider to be excellent and progressive – and I ask about details of the mechanism. The purpose is to advance and clarify, not to snipe. Geoff S

Reply to  Willis Eschenbach
January 9, 2020 1:18 am

Hi Willis,

my theory about why hard limit of Earth thermostat is between 26-29C is this:
Energy for lift of air comes from two sources:
1. water vapor – steam is lighter than air, 1m3 of steam at 1 bar/100C weights 0.59kg comparing to 1.15kg of dry air
2. hot air – hotter air is lighter than cold

Potential energy formula is mgh. Weight of 1m3 air is 1.15kg, gravitational constatnt 9.8ms-2. What is important and only variable is h – height.
From this formula we can derive how high can 1.15kg of air get when receiving some amount of energy.
Absolute humidity at 30C is around 35g of water per m3 of air.
Vaporization/condensation energy of this amount of water is 79kJ (2257000J/kg x 0.035kg)
Heat energy of dry air is 11.6kJ (10C temperature daily swing, 1005J/kg capacity, 1.15kg per m3)
Together it is 90.6kJ of energy.
From mgh fromula we can get that this amount of energy can propel 1.15kg of air 8040m high.
This is very close to thunderstorm clouds height.
Condensation level is practically fixed. LCL (Lifted Condensation Level) as derived on Wiki is counted as 125(T-Td) where T is ground temperature and Td is dew point temperature.
So by providing sun energy we are lifting air mass proportional to this energy. When this mass reaches LCL height it starts to condense as cumulus and create negative feedback.
Simply all additional energy to system is creating cloud cover until system returns to base energy content.

Geoff Sherrington
Reply to  Peter
January 9, 2020 2:11 am

Getting close by describing a limited process, but does your mechanism adjust for changes in insolation? Less sun energy in means less lifting energy so less cooling so system is not stable? Geoff S

Reply to  Geoff Sherrington
January 9, 2020 2:39 am

I’m not fully sure I got your question, but this mechanism apparently works as upper hard stop, so if you provide less lifting energy that simply means that clouds will not from at all or will form less energetic kinds. e.g. cumulus only, no cumulonimbus.
System can be stable with less energy budget. So with less insolation you can get to state where there is mild 23C with few cumulus on the sky never growing to storm for example.

Ben Wouters
Reply to  Peter
January 9, 2020 4:00 am

Peter January 9, 2020 at 1:18 am

1. water vapor – steam is lighter than air, 1m3 of steam at 1 bar/100C weights 0.59kg comparing to 1.15kg of dry air
2. hot air – hotter air is lighter than cold

Rising air does indeed rise because it is lighter than the surrounding air.
The amount of Water Vapor is pretty much irrelevant for its weight, temperature is the deciding factor.
Rising air cools according the Dry Adiabatic Lapse Rate (9,8K/km) until it begins to condens.
The condensation releases latent heat, so the rising air now cools according the Saturated Adiabatic Lapse Rate, until all latent heat has been used, and it cools again according the DALR.
Of major importance in this proces is the temperature profile of the “static” atmosphere the convecting air rises into.
eg a temperature inversion will pretty much stop any convection.

Condensation level is practically fixed.

Not really, it can be anywhere from close to ground level up to 2000m or higher.

In the tropics the warmer air can “hold” more WV and thus has more latent heat to “burn” while rising.
Usually thermodynamic diagrams are used to plot all these data.
See for a nice summary:

Reply to  Ben Wouters
January 9, 2020 5:08 am

Ben, I tried to approach this problem from totally different side, energy content point of view. You can derive dry Adiabatic Lapse Rate and find where condensation occur from PVT formula, use various functions, integrals etc.
So I looked on it from point of energy preservation, where I assume how high can warmed moist air reach. Directly change thermal and evaporation energy to potential energy.

Condensation level is practically fixed.
I meant that condensation level in absolute dry air and in tropics. Condensation level in moist air is just temporary state.
Otherwise condensation level in absolute dry air is linearly related only to ground air temperature, while energy content of WV in air is in exponential relation to temperature.

Ben Wouters
Reply to  Ben Wouters
January 9, 2020 12:56 pm

Peter January 9, 2020 at 5:08 am

Directly change thermal and evaporation energy to potential energy./blockquote>Air volumes rise because they are lighter than the surrounding air, making them buoyant. They are basically pushed up by the pressure of the air below.
No energy is used to gain altitude.

I meant that condensation level in absolute dry air and in tropics.

Rising absolute dry air (RH = 0) will obviously not condense, so talking about a condensation level in this case makes little sense.

Ben Wouters
Reply to  Ben Wouters
January 9, 2020 1:15 pm

Willis Eschenbach January 9, 2020 at 8:38 am

In fact, the amount of water vapor is crucial in the persistence of thunderstorms. This is because water vapor, with a molar mass of only 18, is much lighter than air with a molar mass of 29.

An often seen misunderstanding. The amount of WV is indeed crucial, but the reason is the latent heat that is released during rising that slows the adiabatic cooling (DALR => SALR)
At atmospheric temperatures the weight difference between 0% and 100% RH is small to nonexistent.
comment image
At even lower temperatures hardly any WV will be present.

But once it gets going, the wind at the base greatly increases evaporation, making the air inside the thunderstorm lighter.

Once a volume is rising it will not be influenced by the surface anymore. Its WV content is set, its RH changes because the rising air cools according the DALR until it reaches condensation level, SALR thereafter.
See the large difference between DALR and SALR in this PDF:

Reply to  Ben Wouters
January 10, 2020 1:05 am

Ben, have column of absolute dry air RH 0%, start to pump in RH100% air with same temperature.
You will definitely have condensation level height for such scenario and will be fixed for given temperature (and air pressure, gravity…)

Really are you trying to tell me that buoyancy of moist air is coming from thin air and there is no energy needed for lifting?
For me math here is clear for 1kg of moist air to lift up 10km high you need energy and this energy is exactly from two sources – additional heat above local average and latent heat of vaporization.
In 10km height you will finally end up with same 1kg of dry air but stripped of water, releasing all its latent heat on the way up.
You need energy for buoyancy.

Ben Wouters
Reply to  Ben Wouters
January 10, 2020 2:44 am

Peter January 10, 2020 at 1:05 am

Ben, have column of absolute dry air RH 0%, start to pump in RH100% air with same temperature.

You wrote earlier

I meant that condensation level in absolute dry air and in tropics.

Condensation level only applies to rising air, so I had to assume 0% RH for the rising air. Air at the surface at 100% RH is fog, so whatever the temperature the condensation level is at the surface.

Really are you trying to tell me that buoyancy of moist air is coming from thin air and there is no energy needed for lifting?

Correct. Just as a boat can float indefinitely without burning any fuel, can a parcel of air rise without using any INTERNAL energy.
Actually the entire atmosphere below the parcel pushes it upward, so that is where the energy is coming from.

For me math here is clear for 1kg of moist air to lift up 10km high you need energy and this energy is exactly from two sources – additional heat above local average and latent heat of vaporization.

For a parcel to become lighter than surrounding you obviously need energy: the sun heating the surface and the surface heating the parcel. Once it has left the surface, it does NOT “burn” energy to rise.

Reply to  Peter
January 10, 2020 6:24 am

boat, or rather bottle can float indefinitely without energy, but you can not sink it any depth/height without any energy. And this is working in reverse with air in atmosphere. Buoyancy is created by energy income (by any means, heat, condensation) then affected mass is just surfacing at equilibrium height after losing this energy.

0m condensation level is just temporary dynamic state, where atmosphere column is not in ideal equlibrium state but somehow disrupted. For example cold front wedging under hot air…
And actual condensation level is function of air moisture. I’m speaking about 0% RH air.
So fog is just thermal thermostat mechanism in reverse process, what was put in the air by incoming energy is going back down after release of energy. Fog is only existing when negative flux of energy is present never positive.

Ben Wouters
Reply to  Peter
January 10, 2020 2:59 pm

Peter January 10, 2020 at 6:24 am

boat, or rather bottle can float indefinitely without energy, but you can not sink it any depth/height without any energy.

Exactly the same for the atmosphere. eg a helium balloon can float high in the atmosphere indefinitely, and has to be pulled down with force, just as a bottle floating in water. That’s buoyancy 😉
Anything will float in air or water as long as its density is equal to the density of the surrounding fluid. Higher density and it will sink (move towards the center of the earth), lower density and it will rise (move away from the center of the earth)

Not sure what you mean with 2nd part.
WV wil start to condense when the air cools below its dew point, whatever causes the cooling.
Rising air expands and thus cools. Air sitting on a cooling surface will also cool.
In both cases condensation will start when that air passes its dew point.

Geoff Sherrington
Reply to  Willis Eschenbach
January 9, 2020 2:06 am

Thank you Willis,
I re-read those 2 essays and still seek to explore – not the mechnisms that you describe as governing the control of conditions, which you have done explicitly well, but more how they know when to stop. As part of how they stop, overshoot or not, I use a set point analogy. So my questions have been about comparator mechanisms rather than mechanisms for change. IMHO, your hypotheses would be stronger if you could show a somewhat constant natural feature that is the “set point”that tells corrective processes when to stop. In tropical oceans that seldom have SST above 30C (I used 27C earlier, too approximate) what tells the systems that 30C has been exceeded and the process needs to stop? There might not be a set point. The foot on the throttle might be pressed to the floor the whole time, setting a limit that cannot be exceeded. Or, some part of the control system might become saturated, and not to be exceeded, perhaps part of cloud nucleation processes, but I am guessing here. The critical control might not even involve temperature centrally or at all, but as you know, climate research fixated on temperature from early in its emergence.
As I say, no sniping here, just trying to poke at ways to advance the narrative. Geoff S

Jean Parisot
January 7, 2020 3:09 pm

Have to model it so it can be called science.

January 7, 2020 3:21 pm

That’s the way, climate science goes ! 😀

John Shotsky
January 7, 2020 3:24 pm

Not quoting any particular part of this well-written article, but I do have a bone to pick with the modelers in general. It is well known that 95+% of the annual emission of CO2 is entirely natural. Man’s contribution is less than 5%. By what stretch of the imagination, then, do modelers glom onto a doubling of CO2 in their models? No WONDER they are all wrong – it is not POSSIBLE for humans to cause the annual CO2 emission to double. Note, of course, that the earth absorbs virtually all of what it emitted during the year, so we are left, at most, with the less than 5% that is human contributed, assuming earth ‘ignores’ that. We should all realize, that if ALL human-oriented emissions of CO2 were stopped in their tracks, it would probably not be measurable. So, given that, let’s spend trillions of dollars to reduce our ‘carbon’ footprint to some arbitrary previous year? Doesn’t ANYONE see that reducing emissions to the level of some previous year would be immeasurable in the scheme of things. The earth is gonna do its thing each year, whether humans are even here or not. Always has.
To that, add that the 5% human contributions (20 ppm) is ‘blamed’ for all the earth’s weather and climate ills. Really? 20 ppm? Doesn’t ANYONE have a sense of scale?

Reply to  John Shotsky
January 12, 2020 1:26 am

If you calculate all burnt fossil fuel burnt since WW II it will come up to an addition of 200 ppm CO2 to the atmosphere. Luckily, the ocean and biosphere have used about half of it for greening the earth. So we left about 100 ppm to the atmosphere, rising the concentration from 300 to about 400 ppm. I do not know where your 20 ppm number is from.

Yes, the biosphere adds much more CO2 to the atmosphere as we human in the autumn, but it uses it again in the spring. So that’s a nullsummenspiel.

January 7, 2020 3:24 pm

It is a big deal that different climate regimes rule at different latitudes. For instance, we have the interesting fact that the tropics are warmer than the equator. link Evaporation and convection remove a pile of heat from the equator. Rain removes the water from the convected air in the upper atmosphere. Radiation to outer space removes a lot of heat. The convected dried air descends on the tropics. Because it’s lost most of its moisture, its heat content is lower than when it went up but as it comes down it gains temperature (but not BTUs) as it compresses. Thus the tropics, where the convected air descends, are pretty hot.

The atmosphere is full of interesting and local processes. Most published work tends to treat the planet as a homogeneous whole. That causes a bunch of clueless, pointless arguments about that homogeneous whole which actually doesn’t exist.

January 7, 2020 3:36 pm

I read your thermostat hypothesis essay, all those eleven years ago, and found it elegant — even though my own understanding of our atmosphere was very young and highly unskilled. It just felt right.

It still does. I am extremely grateful for this further exploration. Impressive reasoning sir.

January 7, 2020 3:48 pm


Another excellent post.

I would recommend that this post should be read in conjunction with your previous post of December 26: ‘A Decided Lack Of Equilibrium, Willis Eschenbach’

In the post of December 26, you showed that climate sensitivity, to increased TOA radiation, decreases with increasing temperature, and that feedback becomes negative, over water at temperatures above freezing, and over land at temperatures above about 10 C (Figure 5 from Dec. 26). In this post you have presented the mechanism for this behavior.

As I stated in a comment on Dec. 26, the above phenomena can be readily explained by the properties of water.
1. The partial pressure of water vapor increases exponentially with temperature. Thus evaporative cooling also increases exponentially with temperature. As you note in the text: ‘Not only that, but the minimum amount of annual rainfall increases smoothly and exponentially as the average sea surface temperature goes up’.

2. Water vapor is about 35% less dense than air. As density differences drive convection, the driving force for atmospheric convection increases linearly with the amount of water evaporation, and thus exponentially with temperature.

Your two posts show convincingly how the earth’s water-based biosphere provides a self-regulating mechanism that prevents the earth’s climate from deviating beyond a narrow range, and why the ‘global warming consensus’ is wrong.

January 7, 2020 3:52 pm

We flew down to central South Carolina for the total solar eclipse August 21, 2017. It was a typical very hot August day with cumulus covering about 70% of the sky. Other than the eclipse, the most remarkable thing to me was the clouds just disappeared in about 20 minutes as the eclipse started.. absolutely gone.

Even though it was late afternoon, within 15 minutes after the eclipse, they started reforming. I would not have thought cloud formation was that sensitive to the energy being fed into the system.

Reply to  rbabcock
January 7, 2020 10:21 pm

I find the studies of clouds fascinating. It’s a shame they are ignored because clouds disrupt and invalidate the “CO2 drives temperature” theology. It is a travesty that we have spent so much money on fake climate science and in so doing have lost knowledge and become more ignorant, not less sbout our climate, not to mention all of the horrible harm we have caused to people and Earth and its beauty, animals, birds, insects and biosystems with windmills, solar arrays, biofuels and biomass.

The IPCC itself acknowledges that GCMs can’t actually model clouds, so they’re “parameterized”. That means their effects can be whatever the Planet GIGO computer gamers want or need them to be.
It also means we reduce our knowledge.
97% of climate experts do not understand just how large an issue clouds are for modelers.

Master of the Obvious
January 7, 2020 3:58 pm

Very nice!

During various debates about Lord Monckton’s modifications to the feedback forcing model, the “stability” of the overall climate system got side-swiped on numerous occasions. The feedback, transfer function modelling has no inherent stability but such was implicitly assumed (i.e.: the 1850 base signal was still relevant 170 years on). The attraction to that assumption is due to the observed resilience of the climate in face of perturbations.

This work provides some real chew on why that assumption could be defensible. That is most useful.

The works goes much farther. The postulated decoupling of the heat/humidity cooling effect (via precipitation) from the feedback/forcing mechanisms is very clarifying. One can then make the comparison of the water vapor GHG vs. the CO2 GHG contributions as Willis has shown.

I have to then ask if the solar contribution in Lord Monckton’s model could be similarly decoupled. His work makes a similar comparison of contributions with CO2 forcing getting the short end of that stick. The climate models start-out at dubious and quickly descend towards appalling. Why try to fix stupid?

Instead, decouple solar radiance and water vapor effects and let CO2 GHG stand alone in comparison of their potential magnitudes. Why try to sort-out the mess and make them work together in an attempt to calculate some “equilibrium” temperature. The earth doesn’t have one, it has a steady-state with a central value it’ll chase as all the heat/wind/ice/water vapor engines tussle along.

Coeur de Lion
January 7, 2020 4:03 pm

Pedalling around Singapore dockyard many years ago with one’s Wanchai Burberry one recognised the hotter the day the earlier the inevitable thunderous downpour and temperature relief.

January 7, 2020 4:27 pm

Great post
Good information
Thank you Willis
Of course you have a lot of personal experience with these phenomena having been a seafaring tropics man for so long.

January 7, 2020 4:29 pm

Rain dries the air…whodda thunk it?

January 7, 2020 4:30 pm

That was a very quick eleven years!
Your revisiting the topic is timely and excellent!

Joe Bastardi published this link earlier today:https://journals.ametsoc.org/doi/full/10.1175/BAMS-D-16-0116.1

“The Science of William M. Gray: His Contributions to the Knowledge of Tropical Meteorology and Tropical Cyclones”

Included within is this:

A primary area of Gray’s research in the 1970s was the interaction between cumulonimbus convection and the surrounding circulation. He made three major contributions that stimulated research and left a legacy, described in the following three subsections.

Structure of tropical weather systems.
In a series of papers, Gray and his research team documented the structure of oceanic tropical weather systems using radiosonde compositing (as described in the “Tropical cyclone composite studies” section below; Williams and Gray 1973; Gray et al. 1975; Ruprecht and Gray 1976a,b; McBride and Gray 1980).

Within a scale of several hundred kilometers, the weather systems identified were cloud clusters as defined by the large areas of upper-level cloud identified through satellite imagery (Williams and Gray 1973).
In recent decades, a similar system would be described as a mesoscale convective system (MCS). Modern studies focus on the structure of the embedded squall lines including downdrafts, stratiform regions, and midlevel mesoscale convective vortices [see review of Houze (2004)]. The structure documented by Gray represents the parent synoptic-scale structure, or a “grid-scale average” over the mesoscale components.

The basic dynamic structure documented was a two-layer structure, with inflow (convergence) and cyclonic vorticity from the surface up to approximately 400 hPa, capped by a layer characterized by divergence and anticyclonic vorticity. This had several implications that were revolutionary at the time, including that

the boundary layer inflow is a contributing, but not dominant, component of the mass convergence into the weather system;
the maximum vertical velocity of the system is in the mid- to upper troposphere; and through the approximate balance between diabatic heating and vertical motion (Frank 1980; Fraedrich and McBride 1989; Sobel et al. 2001), the heating profile also has a maximum in the mid- to upper troposphere.

The implications of this two-layer structure are far reaching and implied in all subsequent dynamical models of large-scale tropical convective structure. In particular, the findings described in points 2 and 3 above influenced the development of cumulus parameterization through the requirement that the cumulus heating profile is at a maximum in the mid- to upper troposphere (Yanai et al. 1973; Arakawa and Schubert 1974; Johnson 1984; Frank and McBride 1989; Houze 1989).

The thermodynamic structure revealed in these studies is weak temperature perturbations (∼1°C) that were centered around 300 hPa. The major thermodynamic finding is that the large-scale areas containing tropical convection (the cloud clusters) are significantly more humid through the depth of the troposphere than the surrounding clear areas or regions containing no tropical convection.
While seemingly trivial in modern days, this finding had major implications and still motivates modern research on convection. For example, the introduction to a major work on moisture–convection feedbacks in the tropics (Grabowski and Moncrieff 2004) cites this finding as being the basic observation motivating their theoretical development.
A second example is in the developing science of aggregation of convection, where the large relative humidity differences between convective and nonconvective regions play a significant role (Tobin et al. 2012; Wing and Emanuel 2014).”

January 7, 2020 4:31 pm

Willis, a very interesting article.

But just so’s I can claim to be consistent, what would you offer as the null hypothesis on this, as I’ve asked Messers Stokes and Mosher for on another post here.


Reply to  Willis Eschenbach
January 7, 2020 6:13 pm

That’s all Greek to me Willis 🙂

January 7, 2020 4:40 pm

“the earth’s temperature has stayed in a surprisingly narrow range, e.g. ± 0.3°C over the entire 20th Century. ”

This describes my problem with “Climate Change.”
I have an expensive microprocessor controlled thermostat controlling my Heat pump. I also have a home weather station which keeps track of both indoor and outdoor parameters. A review of the data that this system provides indicates that the “state-of-the-art” thermostat can not keep my well insulated home [with all windows on the south side using solar shielding,] within +/- 1 degree F during one single day/24 hour period. Makes no difference if Summer, Winter, Fall, or Spring, It just can not keep the temperature within one degree of the setpoint. {This fact gives me concerns of these new regulations on insulation and sealing requirements of homes.] And I live in a ranch house! For a less than 1 degree F change of the “Global Average Temperature” [whatever that is] over 100 years convinces me that there is no statistically significant “Climate Change.” I sincerely believe that if all UHI temperatures were removed from the data creating this Global Average Temperature, that the actual increase in temperature would be farr less. Why has no one done this simple exercise?

Reply to  Uzurbrain
January 7, 2020 6:34 pm

My forced air heating system keeps the thermostat within +/- 0.5 F. Anywhere else in the house is a different kettle of fish. 🙂

Reply to  Uzurbrain
January 7, 2020 7:25 pm

Tony Heller has a great video on this: “How Homogenization Destroys Climate Science”

Reply to  Uzurbrain
January 7, 2020 8:26 pm


The sun is constantly shining on the earth, hence the relatively stable global mean. Is the sun constantly shining on your house?

BTW, the global mean temperature varies MUCH more than Willis says, about 2.3 C (4 F) every year.

Reply to  Willis Eschenbach
January 8, 2020 12:35 am


The sun is constantly shining on the earth SYSTEM. I thought that was a given.

We need to use anomalies where appropriate, not as a generic rule.

There is little change in the GM temperature anomaly from, for example, from one aphelion to the next….. because there is very little change in radiative forcing from one aphelion to the next.

When there IS a large change in radiative forcing, there IS a large change in temperature.

Not just aphelion to perihelion, of course. Volcanic eruptions, changes in albedo, Milankovitch cycles… all these have produced large changes in radiative forcing, and consequently large changes in global temperature.

This simple fact debunks the “thermostat” hypothesis.

Note: Global land areas, on average, receive the most radiative forcing during aphelion. The land heats up very quickly and the atmosphere responds in kind.

The global oceans get warmer during the perihelion, when the sun is closest, but not fast enough to make up for the more rapid land area cooling.

Reply to  Snape
January 8, 2020 1:23 am

Just to be clear about the anomaly issue:

If, say, the average GM of 30 aphelions is 19.0 C, and this year at aphelion the GM was 19.3 C, then this represents an anomaly of + 0.3 C

If, say, the average GM of 30 perihelions is 17.0 C, and this year at perihelion the GM was 17.3 C, then this represents an anomaly of + 0.3 C

In the above example, there was no change in anomaly from aphelion to perihelion. There WAS, however, a change in temperature. And this change in temperature was the result of changes in radiative forcing.

January 7, 2020 4:45 pm

Very interesting data presentation Willis. Weather as a surface cooling mechanism. Why are we surprised, convection was always a two-way vertical process. Nice to see the character of it confirmed in data and the result visualized within a 3D physics depiction.

January 7, 2020 4:46 pm

Thanks to Willis for this important post. You can easily see the temperature changes caused by clouds in GOES-=16 lower and middle troposphere imagery. For initial viewing, select the full Earth view and look at the southern hemisphere where summer is occurring. For example, this selection clearly shows major cooling across most of Brazil caused by abundant cumulus clouds:

Steve Keohane
January 7, 2020 5:01 pm

The fourth transition brought to mind Frost’s; ‘The line-storm clouds fly tattered and swift’

January 7, 2020 5:13 pm

e) Wind created waves also create turbulence in the water which mixes surface water that has just been cooled with deeper layers that have not been cooled yet.

(Cooler water is denser and would be expected to start sinking, however the turbulence would mix the layers much faster.)

Julian Flood
Reply to  Willis Eschenbach
January 8, 2020 3:32 am

Willis, mixing also changes nutrient levels, presumably altering bio activity and hence? albedo.

BTW, wind ruffled water has a higher albedo by virtue of the ruffling, not just foam. There’s a paper modelling the effect but I’m on my phone and can’t find it. *

While I’m here… The UK has deployed a grid of soil moisture monitors which use cosmic rays – Cosmos? Early days, in twenty years time you’ll have more fun data to play with.

*Oil pollution reduces ruffling. Oil pollution reduces foam. Oil pollution reduces mixing of warmth and nutrients. Oil pollution reduces aerosol production which reduces stratocumulus cover over the oceans.

All the above mean s your thermostat will trigger earlier, raising average global temps but still not exceeding the thermostat setting by much – that would require total suppression of the cunims.

J Mac
January 7, 2020 5:25 pm

Your article above is a wonderfully comprehensive summation of your Thermostat Hypothesis. Your narrative allowed this reader to mentally visualize the sequential phenomena, driven by the embedded physics, with a clarity I had not achieved before. I’ll never look at a towering cumulonimbus thunderstorm again, without seeing the symphony of physics driven emergent phenomena that produced it, as you so aptly described!

Steven Mosher
January 7, 2020 5:37 pm

“Despite that, the earth’s temperature has stayed in a surprisingly narrow range, e.g. ± 0.3°C over the entire 20th Century. ”

since 1900 to 2000 about +.6
past 2000 ~.2c per decade.

Reply to  Willis Eschenbach
January 7, 2020 6:58 pm

You have done a nice job describing some of the negative feedbacks of water vapor. Still, the equator absorbs more solar radiation than it emits to space:


The excess energy is shared with the rest of the planet.

Reply to  Willis Eschenbach
January 7, 2020 7:30 pm

This negative feedback along the equator (due to an increase in convective cooling) results in an increase in advective warming at the mid latitudes and poles.

Reply to  Snape
January 7, 2020 9:08 pm

Please see my reply to Usurbrain upthread.

The earth’s land areas experience an increase in solar forcing during the aphelion. The global mean temperature does NOT remain stable, rather increases by about 2.3 C compared to perihelion.

Reply to  Snape
January 8, 2020 2:17 am

“During northern summer the north pole is tilted toward the Sun. Days are long and the Sun is shining more nearly straight down — that’s what makes July so warm.”

Longer days, a more direct angle of sunlight – this is an increase in radiative forcing, Willis, and nothing to do with a spinning skater.

“In fact”, says Spencer, “the average temperature of Earth at aphelion is about 4 F (2.3 C) higher than it is at perihelion.”

“Earth’s temperature (averaged over the entire globe) is slightly higher in July because the Sun is shining down on all that land, which heats up rather easily,” says Spencer.


Joe Born
Reply to  Snape
January 8, 2020 4:22 am

Gotta go with Snape on this one.

He seems to be talking about land rather than ocean, and more land is in summer at aphelion than at perihelion.

Anyway, the fact that the earth-to-sun distance spends more time close to the aphelion value than to the perihelion value isn’t inconsistent with the proposition that forcing is greater at perihelion.

(And, to add to the confusion, I’m told that solar days are actually longer at perihelion.)

Kevin Kilty
Reply to  Snape
January 8, 2020 7:55 am

Snape and Willis are speaking about different things here. Snape speaks of the peak of instantaneous solar irradiance, which is, indeed, of greater magnitude at perihelion than at aphelion. Willis is referring to the shape of the solar irradiance versus time curve, which is not a nice sinusoidal sort of thing, but has a sharper peak at perihelion because of change in orbital speed. Over the course of a year the two hemispheres receive nearly insolation.

Reply to  Snape
January 8, 2020 4:12 pm


The subject of aphelion/perihelion is messy and hard to keep straight. Here is my novice take:

First, by the term “radiative forcing”, I’m talking about the watts/m^2 absorbed by a solid, gas, liquid – whatever.

Dr Spencer says,
“Averaged over the globe, sunlight falling on Earth in July (aphelion) is indeed about 7% less intense than it is in January (perihelion).”

So the radiative forcing to the global land/ocean is greatest at perihelion, which falls on January 4th, the middle of Southern Hemisphere (SH) summer. This is NOT due to axial tilt.

Perhaps coincidentally, the SH summer solstice is just two weeks earlier, on December 21st. This IS due to axial tilt. The SH is tilted furthest towards the sun.

The SH, therefore, has its longest days and most direct angle of sun, at nearly the same time as the planet as a whole receives the greatest solar insolation!

As noted, all that solar energy falls mostly on the SH’s vast oceans, whose surface is slow to warm up.

Meanwhile, the Northern Hemisphere land area is close to its annual minimum temperature.

Reply to  Steven Mosher
January 7, 2020 6:38 pm

+/-0.3 is 0.6

David Dibbell
January 7, 2020 6:49 pm

Willis, thank you for continuing to study and write about emergent phenomena and the self-regulating nature of tropical weather. Nicely done once more. This stands sensibly against the claims of harmful warming driven by greenhouse gas forcing. But even further, perhaps there are also good arguments to be made for what increased carbon dioxide concentrations should do to these self-initiated processes and transitions. For example, other things being equal, an incrementally stronger radiative coupling between the surface and the dense lower atmosphere should promote the transition from still air to Rayleigh-Benard circulation, should it not? The static greenhouse effect is well-understood, but once put in such powerful motion, the atmosphere performs as a heat engine as you so effectively describe.

Ulric Lyons
January 7, 2020 7:10 pm

“In addition to the increased evaporation, the effect they discussed is that the dryer air descending around the thunderstorms reduces the amount of the world’s main greenhouse gas, water vapor, that is between the surface and outer space. This allows the surface to radiate more freely to space, which also tends to cool the surface.”

Don’t forget that water vapour absorbs around 16% of solar shortwave in the near infrared, so daytime surface temperatures get hotter while the nights get cooler, like in the dry horse latitude deserts. Very informative post otherwise.

Reply to  Ulric Lyons
January 7, 2020 9:57 pm

“In addition to the increased evaporation, the effect they discussed is that the dryer air descending around the thunderstorms reduces the amount of the world’s main greenhouse gas, water vapor, that is between the surface and outer space.”



“….. a warmer atmosphere can carry near-exponentially more water vapor as it warms, making droughts less likely, not more likely. The Clausius-Clapeyron equation, one of the very few proven results in the slippery subject of climatology, mandates that a warmer atmosphere will be a moister atmosphere.”

“Sure enough, the atmospheric layer at the surface (the red arrow on the above graph) shows an increase in specific humidity precisely in line with Clausius-Clapeyron.”


Ulric Lyons
Reply to  Willis Eschenbach
January 8, 2020 6:02 am

Fair enough, 16-17% is the total atmospheric solar absorption, though the level of water vapour absorption has been updated. CO2 absorption of solar shortwave is tiny.


A C Osborn
Reply to  Willis Eschenbach
January 8, 2020 6:09 am

Mr Eschenbach, that is not quite what Ulrich said.
He said 16% of Solar SHORTWAVE.

This study, like many others confirms your Thunderstorm, or for that matter any kind of Ocean cloud generation.
The use of later data like CERES to confrim it is great.

I have a question as you mentioned Cold Rain as a coolant, do we have any measure of the difference it makes over sea & land?

Ulric Lyons
Reply to  Willis Eschenbach
January 9, 2020 11:40 am

Is 46 W m^2 for a global mean water vapor near infrared absorption trivial? The range will be larger than the mean.

Kevin O'Brien
January 7, 2020 7:32 pm

Thanks Willis. I wish there more real scientists like you, whatever they are called.
I know your phenomena well. I lived in Samoa 7 years and the evenness of the temperature was amazing. It was basically 29 deg. C all day and night everyday. When it dropped two degrees I put a jersey on.
The clouds rose like clockwork and the cooling was quickly sensed.

What is really amazing is the fine regulation over the century.

Harri Luuppala
January 7, 2020 9:56 pm

Excellent article.

It is not just the temp, but the speed of rising air coupled to the water (humidity).

Check the Picture 2a in the attached study. The air flow rate (Nm^3/h) and water flow rate increseases rapidly when air flow rate reaches 2.6Nm^3/h at 27°C.

Richard G.
January 7, 2020 10:04 pm

W. Thanks for the great bowl of brain chowder. Delish. Glad to see you are well.
I really like this paper of yours.
I would suggest that what is missing from your charts of cloud tops and such is the context of Temperatures Aloft that the clouds are existing in, and how rapidly the air temperature and pressure/density drop with height. Many people don’t appreciate how cold the air aloft is.
For example, NOAA Aviation Weather Center tells me the current (02 Zulu-06 Zulu) Temps aloft for Hawaii are: 15,000 ft -1 C, 18,000 ft -11 C, 24,000 ft -23 C. Those are negative. Freezing. This is why the clouds are dumping so much latent heat as IR outgoing.

Anecdotal evidence of Infrared Signature of cloud IR emissions:

Description of Col. Robin Olds, Triple Ace, engaging a MIG fighter over Vietnam:
“He then let loose a pair of sidewinders but they tracked towards the infrared heat of the clouds.”

Wings Over Vietnam Mig Killers Documentary 2

So the heat seeking missiles locked on and tracked the IR emissions of a cloud instead of the flaming hot exhaust of a jet fighter.

I chuckle and shake my head as We are consumed with arguing over the thermalization process of CO2 IR absorbtion when the real Thermal Godzilla in the room is cloud emissions and convective transport of heat. The atmospheric heat engine, doing the work of regulating the Earth’s climate.

Why don’t the GCMs deal with clouds? No wonder they fail.

A healthy and happy new year to you and your former girlfriend.
And to Anthony and Crew.

Richard G.
Reply to  Richard G.
January 7, 2020 10:53 pm

I omitted the pressure data. At sea level, 1,000 hPa, at 18,000 ft, 500 hPa. So at 18,000 ft the air (and therefore corresponding constituent CO2) is 1/2 as dense as sea level.

Reply to  Richard G.
January 8, 2020 6:35 am

Thanks for reminding me of that anecdote. Was common knowledge back then. I have often wondered how satellites compensate for this phenomenon.

Reply to  Richard G.
January 8, 2020 9:23 pm

I did some research for the RAF in the 70s looking into the problems encountered with clouds using certain IR missile tracking systems. The problem turned out to be scattering of the emissions from the engines rather than IR from the clouds themselves, the systems used back then used the 3-5 micron wavelengths rather than the 15 micron wavelengths emitted by the clouds. The size of the droplets in the clouds had peak scattering at the 3-5 micron range which was a problem. Later systems used two wavelengths, one of which is a longer wavelength which has much better transparency but is still sensitive to the emissions from the fuselage which makes it less likely to miss. Sidewinders had a less than 20% success rate in Vietnam.

Richard Brown
January 7, 2020 10:32 pm

Hi Willis, I’ve lived on tropical islands in PNG on and off for the past 40 years and the weather you describe is real. Unless you’ve experienced daily thunderstorms and the immense rain they can produce plus the reduction in temperature, I doubt many people intuitively understand the cycle that keeps the oceanic tropics at such an even temperature. Just finished 2 years work on Lihir and the temperature rarely goes above 32C or below 26C. Big rain that can dump 100mm in an hour but 2 hours later everything is back to normal.

Bill Treuren
January 8, 2020 12:00 am

Enjoyed that a lot.

The proportion of the earths disc that faces the sun that is governed by this process is quite large.

In my mind the portion that is not part of this system is to a large extent a cosmic radiator of the planet given the modest energy incident per M3.

Interesting to note that that portion of the planet is the portion that varies so much in temperature.

John Peter
January 8, 2020 12:40 am

Interesting article, but how does our earth flip into and out of ice ages if the temperature is so stable?

John Tillman
Reply to  Willis Eschenbach
January 8, 2020 6:26 am

Due to increased albedo from larger ice sheets, glacials get much colder than the relatively brief interglacials, as now.

But the present Cenozoic ice age is balmy compared to past Snowball Earth episodes, when average global temperature sank to around -50 degrees C.

Thus, the range of our planet’s temperature since its crust cooled covers some 75 degrees C. Maybe a bit more, with the odd spike to 27.

January 8, 2020 3:22 am

Excellent article Willis.

I particularly like your Tao buoy plot showing the dramatic drop in solar insolation as cumulus clouds form and how this effect would dwarf CO2 forcing.

A suggestion that might be interesting to extend the argument you are making relate to your final graph showing absolute humidity – what is the change in forcing due to water vapour as a function of absolute humidity and how much does the water vapour forcing drop as the absolute humidity drops to zero?

I suspect the answer may be complex as the thickness of the layer may have to be assumed, but putting even an approximate number on this might again demonstrate the magnitude of the dry air effect versus putative CO2 forcing effects.

A final point might be to consider the actual change in radiative forcing due to CO2 (not a doubling, but actual PPM change per year causing actual forcing addition per year) and state that in terms of how much longer the “cumulus notch” would exist for per day in order to completely negate the CO2 effect. I suspect it would be quite a small additional time, given the size of change from 750 W/m^2 to around 200 W/m^2 observed.

Anyway, great article and one to keep in my archive for sure!

John F Pittman
January 8, 2020 4:25 am

Willis, your scatterplot Cloudtop Altitude vs SST indicates positive feedback to ~12C, transition ~12C to 26C, negative feedback >26C. I don’t know if you pointed it out or just assumed it would be understood, that the positive feedback below ~12C was part of keeping the system towards equilibrium. I believe this agrees with K&E “Such dramatic drying would reduce the greenhouse effect associated with the water vapor, and thus, would lead to cooling of the SST, which in turn may disaggregate convection. This would re-moisten the atmosphere, increasing the water-vapor greenhouse effect, and, consequently, warming the system. So, as in self-organized criticality (SOC), the tropical state would be attracted to the transition critical state between the aggregated and disaggregated states.”

My experience is a good control system fluctuates between the “low” and “high” forcings.

Crispin in Waterloo but really in Goleta
January 8, 2020 4:41 am


Great extension of your earlier work to which I have referred many people.

You mention your interest in emergent phenomena. Something you may not have noticed is the top-view shape of the cells you illustrated from the side. An emergent phenomenon is that such cells are first square when viewed from above!

When a plate is heated from below, and a fluid like air or water transfers the heat to a cooler plate on top (think outer space) the cells that form are initially square and evenly distributed across the surface.

As the temperature difference increases, the cells reform into a hexagon pattern. Both patterns are emergent and not predictable from early observations.

You might appreciate looking at Adrian Bejan’s “Convection Heat Transfer” textbook which shows different patterns that emerge at different delta T’s. It is in the section on heating between closely spaced plated. He provides photos of the patterns that emerge at different heat transfer rates.

As the vertical space between the two plates is changed, the distribution pattern changes. He provides the math behind this. It is appallingly complicated.

Remember that Bejan looked at the global warming issue and famously said, “It is a problem so simple that it is not even interesting.”

I suspect that your observations of thunderstorms can be extended to show which spatial pattern has emerged. Adrian’s math can explain when and under what conditions that pattern can be expected.

Robert Watt
January 8, 2020 5:07 am


Thanks for your paper which explains how the earth’s oceans, atmosphere and cloud systems react to incoming solar energy to control SST, in terms that this layman can understand. As you observe in one of your comments, even when orbital changes resulting in less insolation at higher latitudes occur (ice ages?) the temperature regulation by tropical cloud systems will still function, albeit at a different equilibrium temperature than exists today.

For large temperature regulating cloud systems to form over the earth’s oceans requires the availability of a plentiful supply of CCNs. Perhaps, Henrik Svensmark’s GCR theory and CERN’s CLOUD experiment may explain where at least some of these CCNs come from.

In my opinion, your paper ‘hits the nail on the head’ where it suggests that radiative forcing by CO2 and water vapour has little effect on the daily regulation of SST. This set me wondering whether some sort of laboratory experiment might be possible to try and get some figures for what the CO2 ‘magic molecule’ can and can’t do. Would it be possible to construct a chamber containing only dry air, transmit energy equivalent to solar at 2.7, 4.3 and 15 micrometre wavelengths through the chamber and measure what comes out the other side. This process could be repeated a number of times with the chamber containing dry air plus 50 ppmv increments of CO2. Such an experiment might reveal whether there is a ‘saturation point’ above which CO2 concentration has no further radiative forcing effect.

January 8, 2020 6:00 am

Willis congrats on fine work. Your scatterplots above 26C conform to MEI, OLR and Nino34.

comment image?dl=0

CO2 starts outgassing at about 25.6C, but it lags MEi. OLR, Nino34 by 1-2 months.

comment image

The CO2 outgasses nearly concurrently, so is mistaken for the cause of the heat.

Randy A Bork
January 8, 2020 6:33 am

This scatter plot, Cloudtop Altitude vs SST, as well as those from previous posts on the phenomena are fascinating to me. One would like to see climate science attempt to predict from first principles why the inflection point [or to use terminology from K&E 2010, “transition critical state”] is where it is. It seems this data shows it exists, and where it is. Why is it at that temp?

It seems also to reject that notion [null hypothesis] that ‘delta Temp = lambda times delta Forcing’ completely, at least as for lambda being a constant rather than a dependant variable.

January 8, 2020 7:27 am

Not to take the thunder out of the data, but is the necessary lighning also “emergent”.

Thunder is repeated here so often no quote is possible.

And that phrasé “self-organized” seems rather vague.

Does that mean statistical likelyhood, or an entropy MaxEnt phenomenon?

Aside – H2O IS playing the leading role here.

Reply to  bonbon
January 8, 2020 2:05 pm

MaxEnt is a measure of self-organizing stability.
Just for discussion here :
and now on a galactic and DNA scale , linked to WUWT recently :
The latter paper is very curious indeed.

Johann Wundersamer
Reply to  bonbon
January 20, 2020 9:47 pm

“Not to take the thunder out of the data, but is the necessary lighning also “emergent”.” :

Lightning, as the name implies, goes by speed of light, it radiates energy to the surrounding atmosphere which causes ultrasonic waves – here’s your thunder!

Kevin Kilty
January 8, 2020 8:22 am

Very interesting post, Willis.

The mechanism you describe in the tropics operates to a lesser degree in the mid-latitudes as well. It operates mainly during the summer months May through September where I live. One cannot help but notice that once isolated thunderstorms appear they tend to clear air between them. Now this has the effect of letting LW radiation leave the surface more readily, but lets sunshine in. The cirrus clouds blowing off the top of thunderstorms also reduces sunshine, but has an effect of probably increasing the LW radiation returned to ground, and so forth. So, there are multiple effects in both directions. When I picked up an old Eppley model 10 early last summer at auction, I was surprised by the magnitude of the solar irradiance decline below the most tenuous of cirrus clouds. I now have a pair of PIR and SPP radiometers with which I plan to build a portable “Surfrad” sort of instrument for atop my field vehicle which I can let record when I go hiking or rockhounding.

Here is one nitpicking point. You refer to the convection as “Rayleigh-Benard”, but really it is much more complicated than that. The Rayleigh-Benard sort of convection has fixed temperature boundaries, and the energy absorbed at the warmer boundary is given up at the cooler boundary. Classical R-B convection has a number of transitions such as the onset of convection and the eventual onset of aperiodic motion. Yet there is nothing like the exchange of sensible and latent heat, nor the large effect that variations in absolute humidity have on air density, nor the rather large effect of dilation that condensation must produce in the real atmosphere; and all these effects operate internally to the convection cell.

January 8, 2020 9:52 am

“Just as we saw in the movie above, when the sea surface temperature goes over about 26°C thunderstorms explode vertically, getting taller and taller. This is clear support for the idea that the transition between states is temperature-threshold based.”

Am I the only one that noticed the 26°C cited above also, coincidentally, is the minimum sea surface temperature required for tropical cyclone formation? I’m sure that’s not a coincidence.

Harry Passfield
January 8, 2020 1:28 pm

Fascinating post. I was taken with the stance of some commenters who were trying to get you, Willis, to prove something that had already happened (Duh!)- whereas, we sceptics have been trying to get alarmists to offer proof of something that they say has yet to happen. I know where I stand on this: WE.

January 8, 2020 2:08 pm

Willis, great analysis. One question??

“Despite that, the earth’s temperature has stayed in a surprisingly narrow range, e.g. ± 0.3°C over the entire 20th Century. This represents a temperature variation of ±0.1% during a hundred years. ”

What is the variation in degrees Kelvin? Blackbody cooling rightly exists in degrees Kelvin.

Reply to  Willis Eschenbach
January 9, 2020 12:45 pm

So is ±0.1% of ( Celsius + 273.15) or ±0.1% of Celsius. I was pointing to the stability variation in absolute temperatures. 0.3 / ( Celsius + 273.15) <= 0.001

Ok, I should have done the math before I posted. I hate it when I miss the nail and hit my thumb. Anyway I do love your posts and talks.

January 8, 2020 3:45 pm

For a modern, scientifically accurate explanation of tropical moist convection, whose dominant role in regulating surface temperatures has been known since the last mid-century, see: https://journals.ametsoc.org/doi/pdf/10.1175/JAS-D-12-0273.1

Reply to  1sky1
January 9, 2020 2:46 pm

Nowhere do I claim that the physics governing tropical convective clouds has been “fully” understood since the last mid-century. When neither the history of rigorous science nor its logic is grasped, the CYA resort is ad-hominem-laced tantrums.

Reply to  1sky1
January 10, 2020 3:43 pm

What sort of mind looks for safe spaces?

Cyril Wentzel
January 8, 2020 3:48 pm

Willis, just one question about the utilisation of this excellent work: Is it conceivable at all that you could get it published at all?
My opponents always ask me “well if it is so good why not get it peer reviewed and published?”
Any ideas or experience?

January 8, 2020 5:27 pm


This post is way too long and waaaaay over my head. Can you condense it down to a twitter post for me?


Well done.

Randy A Bork
Reply to  Willis Eschenbach
January 8, 2020 10:34 pm

This reply has me wondering; “Are there instruments in geostationary orbit over the pacific with instruments that can measure the changing IR flux escaping the atmosphere during a full day over the tropical pacific.” I once looked into what was on the GEOS satellites, and it seemed that had instruments of the needed spatial, temporal, and wavelength resolution. But I don’t know if they are calibrated for the purpose, or where the data is binned. But I’m not sure if GEOS West is too far north for the purpose.

Randy A Bork
Reply to  Randy A Bork
January 10, 2020 5:18 am

Closest I got was the page linked here: https://www.ospo.noaa.gov/Products/atmosphere/rad_budget.html

January 8, 2020 6:03 pm

Meanwhile. here on the north shore of Lake Ontario, today, I drove through a dark snow squall streaming off Lake Huron on a ‘partly cloudy’ day.

John Reistroffer
January 8, 2020 6:45 pm

Thank You Willis,

This is an excellent, clear, concise and informative explanation of the processes and related effects associated with cumulus cloud formation.

It occurred to me, while reading your article; that the processes which you describe are a microcosm of those that occur in Hadley cell circulation.

On a larger scale, warm moist air rises in the tropics precipitates rain the returns to the earth’s surface as dry cool air at the “Horse Latitudes”, resulting in humid tropical areas (Brazil and central Africa) and arid areas along the margin of the downgoing cool and dry air in northern Mexico and North and South Africa.

Your graphs of sea Surface Temperature vs Rain per year and cloud top Height and especially the 26 deg.C ocean temperature were especially interesting.

It occurred to me that this important cumulus cloud formation process and critical temperature could significantly be affected by changes in the Pacific Decadal Oscillation and the Atlantic multi-Decadal oscillation, whereby changes in the surface water temperature of global water pools oscillating above and below 26 deg C (your critical observed temperature) would have a profound effect on the global radiator. Positive and negative PDO and AMO systems (and their coincidence and offset in time) which have been positively correlated to regional warming/cooling as well as to rainfall/drought.

I am also curious about how the changes in the altitude of the dewpoint temperature could affect the overall heat transfer from the Earth’s surface to the upper atmosphere, and if these controls change with major decadal oscillations of the Atlantic and Pacific oceans?

However speculative some of these thoughts may be, I am grateful for your excellent review of these very important processes.

Muchas Gracias,

John R.

January 8, 2020 9:53 pm

“…the surface temperature is running some thirty degrees C or more warmer than would be expected given the strength of the sun.”

It seems to me that all the stabilizing mechanisms described tend to cool the surface. How does that increase the surface temperature by 30C, and why precisely 30C?

Andrew Ward
Reply to  Willis Eschenbach
January 10, 2020 12:31 pm

>Next, the earth is warmer than we would expect from its distance from the planet

I think you mean “its distance from the _sun_”

Ian Wilson
January 9, 2020 6:04 am

Your last graph showing the diurnal variation of the absolute humidity anomaly looks familiar. In the tropics, away from areas affected by cyclones, typhoons, hurricanes, and tropical storms, there is an almost universal diurnal variation in mean sea-level (atmospheric) pressure (MSLP). The MSLP reaches a minimum at 4:00 A.M. and 4:00 P.M., and a maximum at 10:00 A.M. and 10:00 P.M. This is exactly the same type variation seen in the absolute humidity anomaly. I wonder if these two phenomena are connected somehow?

It would be interesting to make a plot of the absolute humidity anomaly against MSLP, at a number of representative sights along the equator. According to your graph, there should be a secondary effect caused by the local SST.

January 9, 2020 9:39 am

Your cloud top altitude graphic of this article, and your SST graphic from….https://wattsupwiththat.com/2019/12/26/a-decided-lack-of-equilibrium/
seem to show strong temperature limiting phenomenon at warm SST that would help explain why climate models are not in line with actual readings. In fact force one to the conclusion that the models are lucky to be in the ballpark….

January 10, 2020 3:03 am

Willis, on the subject of turbulence, which is what the atmosphere is all about, we all have a very serious problem.

During his entire career, Richard Feynman had identified turbulence as “the most important unresolved problem of classical physics.” Feynman reported to the British Association for the Advancement of Science: “I am an old man now, and when I die and go to heaven, there are two matters on which I hope for enlightenment. One is quantum electrodynamics, and the other is the turbulent motion of fluids. And about the former I am rather optimistic.” (Parviz Moin and John Kim, Tackling Turbulence with Supercomputers, http://www.stanford.edu/group/ctr/articles/tackle.html)

I think what you mean by “emergent” self-organization is exactly the problem Feynman was not optimistic about. So all climateers are forced into an empirical mode, or a modelling mode with each group, money or politics aside, cornered into huge arguments.

This all began in the 1950’s with the failure to deal with , believe it or not, plasma turbulence, self-organinsing fusion pinches. That is what fusion is all about, and the failure to pursue this even when existing maths cannot handle it, has culminated in an economy with no fusion energy, and an unbelievable decadent quarrel about “climate” with CO2 soothsayers and doom merchants, a real dark age.

In other words, fusion plama pushes self-organied emergent phenomena this to the limit. Climate is by comparison, mild.
I think climate and fusion puts people like Mann in the unenviable role of the emperor with no clothes.

Meanwhile galaxies, stellar systems, DNA, and climate self-organize for everyone to see with wonder.

Reply to  bonbon
January 10, 2020 3:11 am

Dr. Parviz Moin has many publications on this —- the link moved a bit.

Reply to  bonbon
January 10, 2020 4:01 pm

Bon Bon You can regard the graphs of global temperatures as emergent properties of the combined astronomical and solar activity cycles. My WUWT comment of 12/27 deals exactly with your points.
“Simple common sense suggests that a Millennial Solar activity peak was reached in 1991 +/- and a corresponding global temperature peak and turning point from warming to cooling was reached at 2004+/-.It’s not “rocket science” or a “wicked problem” in the long term. Reasonably plausible multidecadal to millennial length forecasts can be made with useful probable accuracy. Shorter term decadal and weather forecasting is much more difficult.
Here is the Abstract from my 2017 paper linked below
“This paper argues that the methods used by the establishment climate science community are not fit for purpose and that a new forecasting paradigm should be adopted. Earth’s climate is the result of resonances and beats between various quasi-cyclic processes of varying wavelengths. It is not possible to forecast the future unless we have a good understanding of where the earth is in time in relation to the current phases of those different interacting natural quasi periodicities. Evidence is presented specifying the timing and amplitude of the natural 60+/- year and, more importantly, 1,000 year periodicities (observed emergent behaviors) that are so obvious in the temperature record. Data related to the solar climate driver is discussed and the solar cycle 22 low in the neutron count (high solar activity) in 1991 is identified as a solar activity millennial peak and correlated with the millennial peak -inversion point – in the RSS temperature trend in about 2003. The cyclic trends are projected forward and predict a probable general temperature decline in the coming decades and centuries. Estimates of the timing and amplitude of the coming cooling are made. If the real climate outcomes follow a trend which approaches the near term forecasts of this working hypothesis, the divergence between the IPCC forecasts and those projected by this paper will be so large by 2021 as to make the current, supposedly actionable, level of confidence in the IPCC forecasts untenable.”
These general trends were disturbed by the Super El Nino of 2016/17. The effect of this short term event have been dissipating so that “If the real climate outcomes follow a trend which approaches the near term forecasts of this working hypothesis, the divergence between the IPCC forecasts and those projected by this paper will be so large by 2021 as to make the current, supposedly actionable, level of confidence in the IPCC forecasts untenable.”
See my 2017 paper “The coming cooling: Usefully accurate climate forecasting for policy makers.”
and an earlier accessible blog version at
And /or My Blog-posts http://climatesense-norpag.blogspot.com/2018/10/the-millennial-turning-point-solar.html ( See Fig1)
comment image
and https://climatesense-norpag.blogspot.com/2019/01/the-co2-derangement-syndrome-millennial.html
also see the discussion with Professor William Happer at http://climatesense-norpag.blogspot.com/2018/02/exchange-with-professor-happer-princeton.html
For the current situation check the RSS data at : http://images.remss.com/data/msu/graphics/TLT_v40/time_series/RSS_TS_channel_TLT_Global_Land_And_Sea_v04_0.txt
I pick the Millennial turning point peak here at 2005 – 4 at 0.58
I suggest that if the 2021 temperature is lower than that (16 years without warming ) the crisis forecasts would obviously be seriously questionable and provide no secure basis for restructuring the world economy at a cost of trillions of dollars.
The El Nino RSS peak was at 2016 – 2 at 1.2
Latest month was 2019-11 at 0.71
However the whole UNFCCC circus was designed to produce action even without empirical
justification. See
” United Nations Framework Convention on Climate Change, later signed by 196 governments.
The objective of the Convention is to keep CO2 concentrations in the atmosphere at a level that they guessed would prevent dangerous man made interference with the climate system.
This treaty is a comprehensive, politically driven, political action plan called Agenda 21 designed to produce a centrally managed global society which would control every aspect of the life of every one on earth.
It says :
“The Parties should take precautionary measures to anticipate, prevent or minimize the
causes of climate change and mitigate its adverse effects. Where there are threats of serious or
irreversible damage, lack of full scientific certainty should not be used as a reason for postponing
such measures”
Apocalyptic forecasts are used as the main drivers of demands for action and for enormous investments such as those in the new IPCC SR1.5 report .”
The establishment’s dangerous global warming meme, the associated IPCC series of reports ,the entire UNFCCC circus, the recent hysterical IPCC SR1.5 proposals and Nordhaus’ recent Nobel prize are founded on two basic errors in scientific judgement. First – the sample size is too small. Most IPCC model studies retrofit from the present back for only 100 – 150 years when the currently most important climate controlling, largest amplitude, solar activity cycle is millennial. This means that all climate model temperature outcomes are too hot and likely fall outside of the real future world. (See Kahneman -. Thinking Fast and Slow p 118) Second – the models make the fundamental scientific error of forecasting straight ahead beyond the Millennial Turning Point (MTP) and peak in solar activity which was reached in 1991.These errors are compounded by confirmation bias and academic consensus group think.
The editors of Science and Nature magazines have acted as Guardians of the establishment position and have sought to promote radical solutions to a non existent warming problem. Most of the MSM, particularly the BBC, and the western eco-left chattering classes now promote anti-development anti-capitalist crisis ideologies based on badly flawed science.

January 10, 2020 7:34 am

Great post and astonishing video of tropical cloud formation — the development of the squall line is amazing.

January 10, 2020 3:36 pm

Willis many thanks for a superb seminal post. Your Daily Solar Energy chart clearly shows the unimportance of CO2 in the process . It would be even more obvious if you had the time and/or inclination to estimate the volume of air, water and CO2 passing through a typical (Model ?)tropical thunderstorm daily and then show the relative energy flows of H2O and CO2. The specific heat capacity of water is 4,200 Joules per kilogram per degree Celsius (J/kg°C).The nominal values used for air at 300 K are Cp= 1.00 kJ/kg.K, and for CO2 Cp 37.35 kJ/kg

Julian Flood
January 11, 2020 3:47 am
Ben Wouters
January 12, 2020 12:26 pm

Willis, I posted a question the 7th, so assume it won’t be answered directly.
I’ll try again.

This is only one of the host of ways that cumulus clouds and thunderstorms keep the tropics from overheating

How do you envision the tropics to overheat?

Tropics are mostly ocean, and a good day of sunshine in the tropics delivers some 25 MJ/m^2 to these oceans. Since the sun directly warms only the upper 5-10 m directly, this roughly enough energy to warm this column 1K. During the night this “stored” energy is lost again to the atmosphere/space.

I’ll expand a little:
our moon is warmed by ~89% of solar. Due to the low heat capacity and low conductivity of the regolith on top of the slower rotation rate the noon temperatures on the equator go to radiative balance temps, ~400K.
In our tropics the atmosphere reduces the amount of solar that hits the surface to ~160 W/m^2 (< 50%).
This amounts to ~25 MJ/m^2 on a sunny day.
Sunlight penetrates the oceans down to max 100m, actual warming is in the upper 5-10m.
Earth has a faster rotation rate, oceans have high heat capacity and high conductivity.
So the 25 MJ/m^2 can warm the upper 5-10m ~1K during the day. During the night this energy is lost again.
(scroll down for the image)

So again my question: how do you see the tropical ocean overheating?

Ben Wouters
January 12, 2020 1:34 pm

Willis Eschenbach January 12, 2020 at 12:45 pm

If there were no clouds to reflect sunlight, the tropics (and the whole world as well) would receive ~ 45 W/m2 more energy on a constant 24/7/365 basis.

Let’s use the same number as for Australian desert in summer (no clouds, little WV): ~30 MJ/m^2.
Enough energy to warm the upper ~7m of ocean 1K during the day, iso the ~6m with 25 MJ/m^2.
No clouds means more energy loss, so the extra energy will be lost during the night again most probably.
I see no reason for overheating at all.

Underlying point is obviously that we must consider the heat capacity and penetration of solar into the surface being heated.
Thinking in radiative balance temperatures works on the moon, but not for our ocean covered earth.

Ben Wouters
Reply to  Willis Eschenbach
January 13, 2020 1:59 am

Willis Eschenbach January 12, 2020 at 3:07 pm

30 MJ/m^2 over how long a time period?

From below the plots: Average quarterly global isoflux contour plots for each quarter in the year. The units are in MJ/m2 and give the solar insolation falling on a horizontal surface per day.

In any case, your point seems to be that if you pick an area where there are no clouds, removing clouds makes little difference

No , my point is that by picking an area like the Australian dessert, it is representative for the maximum energy the sun can deliver in the (sub)tropics in full summer over the course of one day. 30 MJ/m^2/day is the maximum we’ll find on earth.

Finally, I don’t understand your claim at all about the “penetration of the solar”.

Consider a beach, with nearby shallow salt pans filled with seawater (eg 0,5 meter deep) and of course the oceans.
During a day they will receive the exact same amount of solar energy.
The sand will heat up the most, but only some 10-20 centimeters deep.
Next the salt pans, less warm, but at least halve a meter water has been heated.
Finally the ocean, warmed down to 5-10 m, but only 1, maybe two degrees warmer.
So penetration depth together with heat capacity decides how much the temperature will rise during a day.
Same for the seasonal variations.
From this site http://research.cfos.uaf.edu/gak1/
During a whole season of warming the upper surface temp increases some 10 degrees,
deeper water less, below ~250 m no seasonal change at all.
For available energy go to Anchorage on this map:
Units are kWh/m^2/day. Multiply with 3,6 to get MJ/m^2/day.

The incredible stability of Earth’s surface temperatures is due to the oceans imo.

Ben Wouters
Reply to  Willis Eschenbach
January 14, 2020 6:34 am

Willis Eschenbach January 13, 2020 at 10:42 am

However, the problem with that claim is that the Aussie outback is not cloudless. In fact, it has cloud cover some 10% of the time, even in midsummer. So if there were no clouds, even the outback would be hotter …

Fine. Fact remains that it is one of the places with the highest amount of solar/day, together with the other deserts in the high pressure belts N and S of the Equator.
If clouds develop, they certainly won’t be of the Cumulonimbus type.
30 MJ/m^2/day is the maximum amount of solar these charts show.

We’re not talking about a day or a month here.

Do you agree that the beach has the highest temperature swing during a day of the 3 examples, and the oceans the lowest? (beach maybe 30C swing, oceans 1 or 2 degrees.)
If not the difference in penetration depth and heat capacity, what is your explanation.
Realize that the daily tropical thunderstorms mainly develop over (is)land, not so much over sea.

If there were no clouds, after thousands of years the ocean would equilibrate and things would be … well … damn hot. Hotter than the Australian outback hot.

No clouds means more solar during the day, but also more radiative loss to space. It’s far from sure which of those effects overrules the other.
So far the (deep) oceans have on average been cooling down for the last ~85 my.

As you point out, every year the surface temperature of the ocean swings by ten degrees or so … so clearly the ocean can easily and quickly change temperature.

In the example of GAK1 i showed the temperature swing is only for the upper 50m or so, and caused by the variation in solar energy during the day from practically zero in winter to ~18 MJ/m^2/day in mid summer (Anchorage).
Cooling during the winter is limited by the temperature of the deeper oceans.
comment image
The 60N profile shows the temperature below the 250m of the GAK1 plot.
The temperature of oceans below the solar heated surface layer is what creates the base for the surface temperatures. It is about the same for the whole world, and hardly changes on human time scales => stability.

Peter Ibach
January 12, 2020 6:27 pm

Great article, Willis.
When I discussed your article with some folks, they criticized that the first claim doesn’t come with indication of the source:
“…e.g. ± 0.3°C over the entire 20th Century. This represents a temperature variation …”
I know you have stated the 0.3° in several of your post, but I wasn’t able to find to which data this refers. And common temperature series such as GISTEMP show a variation of >1° for the 20th Century.

Ben Wouters
January 14, 2020 6:37 am

Willis, I have quit a few points about your concept of atmospheric convection as used in the main text.
Are you interested to discuss this?

Ben Wouters
Reply to  Willis Eschenbach
January 15, 2020 6:39 am

Willis Eschenbach January 14, 2020 at 8:29 am
Problem is that your concepts are based on two incompatible ideas:
– the atmosphere “further heats” the surface (Lacis ea 2010) above the 255K the sun provided.
– the surface will overheat when the atmosphere does not cool it with clouds, developing CB’s etc.

By introducing a simple idea of using the available MJ/m^2 during a day iso the average W/m^2 a lot of observations make sense. Anyone who has burned his foot soles on a hot beach also has noticed that the water is much colder.
Once you realize that the sun is not warming the entire oceans from 0K to the observed values, but only increasing the temperature of a shallow surface layer a bit, the very high temperatures on earth make perfect sense.
Next step is to accept that the deep oceans are so hot (~275K) for the same reason the continental crust is hot in spite of the low flux (~65 mW/m^2) : Earth’s incredibly hot interior.

And yes, the atmosphere does reduce the energy loss to space, and yes backradiation from the atmosphere does play a role in this process.

Johann Wundersamer
January 20, 2020 9:58 pm

With that compilation of atmospheric / sea surface fluid mechanics, local heat distribution, localised albedo effects ad lib. / ad inf.

– there’s shown: still a long way even for “super-computers” to catch up with.

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