Guest Post by Willis Eschenbach
Clouds are said to be the largest uncertainty in climate models, and I can believe that. Their representation in the models is highly parameterized, each model uses different parameters as well as different values for the same parameters, and so of course, different models give very different results. Or to quote from the IPCC, the Intergovernmental Panel on Climate Change:
In many climate models, details in the representation of clouds can substantially affect the model estimates of cloud feedback and climate sensitivity. Moreover, the spread of climate sensitivity estimates among current models arises primarily from inter-model differences in cloud feedbacks. Therefore, cloud feedbacks remain the largest source of uncertainty in climate sensitivity estimates.
The question of importance is this—if the earth heats up, will clouds exacerbate the warming or will they act to reduce the warming? The general claim from mainstream climate scientists and the IPCC is that the clouds will increase the warming, viz:
All global models continue to produce a near-zero to moderately strong positive net cloud feedback.
My own theory is that clouds and other emergent climate phenomena generally act to oppose any increases in surface temperature. So me, I’d expect the opposite of what the models show. I figured that there should be a negative cloud feedback that opposes the warming.
So I thought I’d take a look at answering the question using the CERES satellite dataset. As a prologue, here’s a short exposition about measuring the effect of clouds.
Clouds have two effects on the surface radiation balance, and thus on the surface temperature. On the one hand, they reflect sunlight (shortwave radiation, “SW”) back out to space, cooling the surface. And on the other hand, clouds block and absorb upwelling thermal (longwave, “LW”) radiation from the surface, and they re-radiate about half of what is absorbed back down towards the surface. This additional downwelling radiation leaves the surface warmer than it would be in the absence of the clouds.
We can actually physically perceive both of these effects. During a clear summer day, a cloud comes over and instantly cools us down. And during a clear winter night, a cloud comes over and we immediately feel warmer.
These two changes, cooling and warming from different phenomena, are lumped together under the term “CRE”, which stands for the Cloud Radiative Effect. As mentioned above, it has a shortwave (SW) and a longwave (LW) component, and when added together these give us the “Net CRE”. Planetwide, as is generally known, the net CRE averages out to a surface cooling effect of about -20 watts per square metre (W/m2). That is to say, clouds cool the surface more than they warm it. Here’s how that plays out around the planet.
Figure 1. Net cloud radiative effect (LW warming minus SW cooling)
Note the strong cooling along the Inter-Tropical Convergence Zone (ITCZ) above the Equator, and in the Pacific Warm Pool north of Australia. There, the clouds are cooling things by up to sixty watts per square metre (W/m2). As a comparison, a doubling of CO2 is said to increase warming by 3.5 W/m2, an order of magnitude less …
And here’s the same image, but from the Atlantic side:
Figure 2. As in Figure 1, Atlantic side. Net cloud radiative effect (LW warming minus SW cooling)
As you can see, clouds have a net cooling effect everywhere except over some deserts and at the poles. At the poles, clouds actually warm the surface. And on average, the cooling is much greater over the oceans (-25 W/m2) than over the land (-8 W/m2).
In short, the clouds are cooling the hot tropics and warming the cold poles, just as my theory predicts.
The real question, however, is not the static condition. It’s what happens as the planet warms. For that, I calculated the changes in the net CRE with respect to surface temperature for each 1° latitude x 1° longitude gridcell. Here are those results, again seen from both the Pacific and the Atlantic sides.
Figure 3. Change in net cloud radiative effect (LW warming minus SW cooling) per one degree C of surface warming. Negative values indicate that there is greater cloud cooling with increasing surface temperature.
And here is the Atlantic view.
Figure 4. As in Figure 3, but an Atlantic view. Change in net cloud radiative effect (LW warming minus SW cooling) per one degree C of surface warming. Negative values indicate that there is greater cloud cooling with increasing surface temperature.
Now, this is a most interesting result. As predicted by my theory that clouds are a major part of the thermoregulatory system keeping the planet from overheating, we find that almost everywhere on earth, as surface temperature increases, cloud cooling also increases (negative values). This is true in both hemispheres, in the tropics, on land, on the ocean, and in both the Arctic and the Antarctic. Only in isolated patches of the ocean does cloud cooling decrease with increasing surface temperature.
I’m currently in the process of writing up my theory that emergent phenomena act to keep the surface temperature within narrow bounds, for submission to some as-yet-undecided scientific journal. This analysis is most definitely evidence in support of that theory, so I’m glad I did this particular piece of work. But man, I hate writing for the journals. I always feel like I need to give myself a lobotomy to write in the thick turgid long-paragraph style that they like. Plus with the small word limits and only a given number of graphics, I feel like I’m fighting with my hands tied.
Ah, well, it’s just another part of life’s rich pageant, and I learned an important lesson in my 17 years living on small South Pacific islands—the universe truly doesn’t give a shift what I want to happen next.
So I’ll just have to keep on keeping on …
Tonight we have rain here in a dry year, so life is good. I got my second vaccine shot two days ago. Other than a sore arm and one day of feeling like I was hastily assembled out of random spare parts, not much in the way of side-effects. People have asked me why I got the vaccine … I say everyone has to decide for themselves the balance between their known COVID risk and the unknown vaccine risk.
Me, I’m 74, and if I didn’t do myself serious genetic damage in the ’60s and ’70s, it certainly wasn’t for lack of trying. Add in the odd co-morbidity or two, not unusual in a man of my late youth. Then there’s the fact that my gorgeous ex-fiancee is a front-line health worker, a family nurse practitioner who is exposed because she administers COVID vaccine shots and gives sports physicals at the local college. (And, I might add, she also did the same before she got vaccinated last month. Big props to her, and to all of the worlds’ medical personnel putting their lives on the line to fight the pandemic.)
Finally, and to our immense delight, our un-vaccinated daughter, son-in-law, and 19-month-old granddaughter are now all living together with us in our big old rambling house in the forest that I built with my own hands …
So getting the vaccine was an easy choice for me … but I don’t fault anyone for whatever they might choose.
Best regards to all, stay healthy,
w.
As Usual: When you comment, I ask that you quote the exact words you are discussing, so we can all be clear as to both what and who you are responding to.
Technical Notes: I’m using the “surf_cre_net_tot” (surface CRE net total) file from the CERES EBAF (Energy Balanced And Filled) dataset for the CRE data. For the surface temperature, I’ve converted the “surf_lw_up_all” (surface longwave up all conditions) CERES file to temperatures using the Stefan-Boltzmann equation. This gives surface temperatures that are slightly different from the Berkeley Earth gridded surface temperature dataset … which in turn is slightly different from the HadCRUT gridded surface temperature dataset … which in turn is slightly different from the GISS LOTI gridded surface temperature dataset … they’re all four close, but which one is right? Nobody knows, so I use the CERES data. It has the huge advantage of agreeing in every gridcell with the energy flows given in the other CERES datasets, including of course the surf_cre_net_tot dataset I used in this analysis.
Wavy jet stream tracks increase the length of the lines of air mass mixing and so produce more clouds which reduces solar energy into the oceans for a cooling world.
Wavy tracks appear to be related to levels of solar activity.
Over time, cloudiness changes affect the balance between El Nino and La Nina events.
We can see that during the recent warming spell there were less clouds, more El Ninos and a more active sun.
If the current solar quietness continues I expect to see more persistent La Ninas and a cooling world with the next PDO related temperature step being downwards after a series of upward steps during the 20th Century.
If that’s your big rambling house, Willis, I’d sign for one. And sea-level-rise-proof too!
Mr. Eschenbach,
Thank you for this work. You have the patience of Job.
A third way they affect thermodynamics in the atmosphere – they provide a surface for gas to conduct heat to which is then radiated to space at a higher rate than the gas is able to radiate it. Temperature inversions form above cloud layers just like at the surface at night, which is yet more proof that the back radiation “greenhouse gas” hypothesis is erroneous.
I suspect that the net change in CRE is due to weather patterns that occur in those regions and the types of clouds associated with those patterns.
“We can actually physically perceive both of these effects. During a clear summer day, a cloud comes over and instantly cools us down. And during a clear winter night, a cloud comes over and we immediately feel warmer.”
Absolutely regarding #1. On a breezy partly cloudy day, alternate sunshine and shadow results in dramatic warming and cooling. But #2? Dunno, maybe I don’t get out at night enough, but if I’m outside on a partly cloudy night I doubt very seriously that I would immediately feel warmer if a cloud came over.
Regarding, “…will clouds exacerbate the warming or will they act to reduce the warming?” Well reflection of the sun’s rays seems to be a primary effect, that is to say, clouds prevent some of the heat from the sun to never reach the surface. Retaining heat from the surface day or night is secondary. After all, it can only retain a portion of the heat the absence of clouds allowed in in the first place.
Thanks for the IPCC link I’ve added it to my file of factoids and suchlike.
Where I live, winter tends to be cloudless and dry. I am always happy to see clouds on a winter night, as it portends a morning after without black frost. Always important for us mudgrub veggie-heads, the frost… and the drought…
HOWEVER
I find this true only for full, horison-to-horison clouds. Whereas I have ample opportunity to enjoy the fleeting pleasure of a small-to-medium cloud blocking the sun’s heat enough to work outside while it lasts, I must say, I have never looked up at one night time cloud and thought; “wow, that’s nice and cosy”. At 1614 meters above sea level, I feel close enough to the average cloud to have noticed?
Thus, sir, I respectfully state my doubts about radiative clouds, I always thought of them more as insulating, keeping the little heat we have in via reflection from below, rather than overpowering the cold by sending me heat. I even considered that they may simply disturb convection, keeping daytime air down near the ground? A type of inversion?
But then, you are the expert, so I’ll keep your theory at the back of my mind until proven wrong. Or right, of course.
One point to add to discussion, downwelling IR is refected at the surface and does not warm the ocean at depth…
“they’re all four close, but which one is right? Nobody knows,”
One of my favorite adages is, ‘A man with a watch always knows what time it is. A man with two watches is never quite certain.’
A very interesting exercise. The side look is how temperature effects the water vapor in the atmosphere which of course effects cloud cover. Additionally one has to consider the inertia from drought and rainy conditions over land (dry conditions perpetuate dry conditions, wet perpetuate wet unless something happens to feed in dry or wet air from elsewhere).
Then you can get to where the atmosphere is so warm as you go up no clouds will form. We have that a lot in the Southeast US in the hot months where we have days where it is very hot, hazy and cloudless. A lot of variables around cloud formation. A sticky wicket as they say.
I’m trying to construct myself a Solar Power Datalogger
You’d have thought = fairly simple.
viz: take a small solar cell panel. Because solar cells are ‘current sources’ you connect a resistor across it to convert the current to voltage and then record the voltage
Easy peasy and inexpensive – big thanks to Lascar for the EL3 data logger
But then, to calibrate the thing
So, get a proper solar power meter (SPM) (
One that not already a logger – not easy to find apart maybe in the proper Weather Station kits. Hideous expensive
Then the fun starts because it is obvious that the solar cell and the SPM don’t see the same sky. SOMETIMES.
Never mind for now
Just a few days ago it was cloudy here at lunchtime:
Get your round head around those numbers then: explain how clouds cause Positive Feedback heating.
Even worse, they simply can not ‘force’ the surface or in fact anywhere in the atmosphere below them.
Lapse Rate says that the cloud, whatever height is it at, is always colder than everything everywhere below it and Entropy says that cold things do not warm warmer things.
Next:
The tops of clouds, in fact ALL parts of clouds, are dazzling white.
Always.
Grey clouds are an optical illusion
Clouds thus have epic high Albedo
But also, they are made of (droplets of) liquid water and thus have very high emissivity, easily 0.99
And where they emit (upwards) from is at the very base of the Stratosphere
(Perhaps remind now that CO2 has perfectly Zero Emissivity)
The Stratosphere being noted not only for its Stratification but also that is is very very dry.
There is no water there and thus, is nearly transparent to the Infra-Red Radiations coming off the tops of the clouds.
Poor hapless old Climate is thus dealt a humongous Double Whammy by the tops of clouds….
Q. Why did the Polar Vortex come pouring down the Great Plains corn belt and dump on Texas and not land on the ocean(s) either side of North America?
A. Lapse Rate
Tillage/farming/corn growing has dried out the land, over huuuuge area.
The air above it was/is very dry so that air would have had a Lapse Rate of 10C per km
Compare to wet air with a Lapse Rate of 6C per km
Thus the thermal gradient above the Great Plains was very steep and whatever energy there was in the dirt/soil/landscape simply poured out, or down (always down) the thermal gradient as heat energy is want to do.
Thus the steeper Lapse Rate very effectively reduced the height of the Tropopause
So: The dry air above the Plains effectively opened the door and threw out the red-carpet Welcome Mat for the Stratosphere to come and pay a visit.
It obliged.
a bit OT…
If anyone is into graphs and correlations, an interesting one to go research is the per capita rate for heart attacks.
Which anecdotally corresponds with places where huuuuge amounts of Roundup are used?
And you thought Roundup caused cancer?!!?
The Great Plains use massive quantities of Roundup. That is why the plants are all dead, the dirt is so dry, the lapse rate is so high and why the stratosphere came calling.
Another place, also bizarrely where its been cold recently and has a high per capita heart attack rate and high Roundup use, is Florida.
Apart from being an Organophosphorus compound, very lovely I’m sure, Roundup is a chelator.
It locks up metals.
Like Zinc, Magnesium, Copper = things that might cause dementias, heart attacks, strokes and ‘co-morbidities’ if they run into short supply………..
funny old world innit
Have you ever stood in the sun then been shaded by a passing cloud? Did that produce heat or cooling?
With my deepest apologies to Joni Mitchell…
Both Sides Now
Woes and blows to warmist scares
Excise schemes now in cross hairs
And weather claxons now despair
I’ve looked at clouds that way
We all know that they block the sun
And rain and snow on everyone
So many things frauds would have done
But clouds got in their way
We’ve looked at clouds from both sides now
From cool and warm, and still somehow
Warmist delusions I recall
They really don’t know clouds at all
Loons and goons with feckless deals
Are busy advancing their ideal
And so their fairytale reveal
We’ve heard them yack away
But now it’s not supposed to snow
So we’re laughing as they eat crow
And polar bears, their numbers grow
Hint: check the Hudson bay
We’ve looked for signs of high tides now
From near and far, no rise somehow
Warmist delusions we recall
They really don’t know squat at all
Tears and fears and feeling proud
To say “It’s bullshit!” right out loud
Dreams and schemes of circus clowns
The crooks’ in disarray
This now transends just acting strange
We shake our heads, they’re so deranged
They’re data’s lost, still unexplained
United Nations way
We’ve heard their crap, their sacred cow
From kin and news and still somehow
It’s Mann’s delusions I recall
He really don’t crap at all
I’ve looked at clouds from both sides now
From cool and warm, and still somehow
Those warmists really are dirt balls
They really don’t know clouds at all
I made pass one through your post, pass two is necessary. Two comments:
Aerosols seem to have much greater uncertainty, but much, much less impact. They do make a good fudge factor though.
I haven’t looked at weather/climate models, but the fact that a visibly transparent atmosphere laden with the greenhouse gas water vapor transforms into a visibly opaque atmosphere with a very high albedo that reflects a huge amount of sunlight is something that I find completely daunting and is far outside anything I have tried to model. The transition can be just a fraction of a degree, 100 meters in elevation (or less!) is just amazing.
I’m sure glad I never had to code atmospheric models for a living.
” Planetwide, as is generally known, the net CRE averages out to a surface cooling effect of about -20 watts per square metre (W/m2). That is to say, clouds cool the surface more than they warm it. ”
Something the ” modelers ” strive to NOT know …
😉
Willis
Interesting article.
Looking forward to your review of cloud cover periodicity.
Forced by changes in the Solar Cycle and Cosmic Rays.
There will be more clouds on the edge of the deserts and elsewhere as the world continues to green thanks to the wonderful plant food, CO2, that is increasing.
Good post Willis, as usual.
However it seems to me that you, and the climate modellers as well, are looking at clouds statically.
I think that you also need to look at clouds dynamically, i.e. the rate of cloud formation and dissipation.
According to the earth’s energy budget in Wikipedia (Dec 29, 2020), evaporative cooling is approximately 85 W m–2. This should necessarily approximate the rate of energy release upon condensation to form clouds. This energy of condensation is largely radiated directly into space, bypassing the green-house gasses.
The rate of evporative cooling, and thus cloud formation, should increase at least in proportion to the partial pressure of water vapor, which increases exponentially with temperature (approximately 8% per degree Celsius), especially when one considers that the mass transfer coefficient for natural convection, which depends on density differences, will also increase with increasing evaporation.
Thus the increase in evaporative cooling with temperature, which drives increasing cloud formation and dissipation, should be at least 6 W m–2 / C and is likely to have a larger effect on the earth’s energy budget than the static effects that you have explored in this post.
So, with all the hubbub about arctic amplification and enhanced warming at the poles, how do we know that CO2 is the culprit and not increased cloudiness? Seems to me that there are at least two confounding factors in that analysis, possibly three if sea ice fluctuation is taken into account.
Clouds, hoo-boy. All types, low, medium, high, thin, fat, short, tall, warming and cooling depending what time of day and where. It’s complicated. Me, I wish I had a river…
As person who is always wanting to figure out how things work, I have never been able to see how CO2 could possibility be the control knob for maintaining the remarkable stability in temperatures over the long term on this planet. Born and raised on the Prairies in Canada I’ve experienced the emergent phenomena of huge cumulus clouds drifting in on a hot summer afternoon and then dropping rain. Even as a child I recognized that things cooled down quickly.
Willis: Thanks, great post. I’ve been telling my “climate worried” family members that the models and predictions are very uncertain mainly because no one knows how big the effect of clouds is on cooling or warming or even the sign of that effect. I will now amend that to say the evidence strongly supports the conclusion it is negative.
(Typo alert: just above figure 3 -grid cells – not in degrees C)
Willis,
If I might be so bold as to state that which you probably already know…
Best wishes on your paper. Your skill at extracting sensible results from those huge satellite databases is admirable.
To me the it is ridiculous to believe that clouds can have a positive feedback that can lead to a tipping point and a “hot house”. In fact I think we have proof that cannot be the case. Why did not the earth get stuck in a “hot house” scenario way back when CO2 was over 2000 ppm ? Clouds are not water vapor, they are water droplets and ice crystals resulting in a net increase in incoming energy being reflected away from earth. Logically, according to me.
Good analysis, as always.
It almost seems as though we are overthinking this issue. A little extra CO2 means a little extra downwelling energy means a little faster convection, i.e. heat transport. A bit more cloud is the signature of the enhanced convection. But clouds reflect incoming radiant energy back into space, and condensation at the cloudtops also releases energy back to space. If there’s a net temp increase it is likely a very small one, and under only certain conditions.
Is it an oversimplification to observe that in nature feedback is always negative because the echo is always weaker than the signal, and the effect always of lesser magnitude than the cause? The idea that there could be some kind of runaway hothouse effect relies on essentially the same logic as Zeno’s paradox.
Nice house, by the way. Not only are you a wizard with data, but you are a craftsman as well.