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.
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“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.”
Cool, a discussion of clouds and psychedelics. I recall one day in ’69, while er… uh… under the influence…. on a nice August afternoon- watching clouds. Greatest light show I’ve ever seen. They looked like one celled creatures under a microscope and every color in the rainbow- plus, they looked like they were only about 100′ off the ground. All the small parts of them were swirling around like crazy and the entire show was at a ultra fast speed. Never to be forgotten. This was a few weeks after going to see “2001 Space Odyssey” at a drive in theatre, also under the same influence. The next morning, my mother asked, “how was the movie?”. “pretty good” I said. After that, I decided to spend the rest of my life hiking the forests of Massachusetts.
looking for more mushrooms, any luck.
never tried those- but a nephew tried them at an outdoor concert in a wooded area- while listening to the music and getting off he started staring at the trees surrounding the site- he told me later, “hey uncle Joe, now I know why you got into forestry”. I enjoyed watching trees dancing like belly dancers- with no wind- waving their branches. After such grooving on clouds and trees- how I could I work in an office or factory? Now I have to listen to the clean and green crowd tell me that forestry is a bad thing- that all forests should be locked up to sequester carbon to save the Earth. I get explicit when I tell them where to go. 🙂
Willis.
Thanks for your analysis.
I think it is important to note that your work concurs with empirical – n.b. not model-derived – determinations which indicate feedbacks are negative so climate sensitivity is less than 1.0deg.C for a doubling of atmospheric CO2 equivalent.
This is indicated by the studies of
Idso from surface measurements
http://www.warwickhughes.com/papers/Idso_CR_1998.pdf
Lindzen & Choi from ERBE satelite data
http://www-eaps.mit.edu/faculty/lindzen/236-Lindzen-Choi-2011.pdf
and Gregory from balloon radiosonde data
http://www.friendsofscience.org/assets/documents/OLR&NGF_June2011.pdf
I especially commend the suite of 8 (yes, eight) “natural experiments” reported by Idso.
Richard
Hey, Willis!
Great post as usual! I look forward to your study as I know it will be well outside the norm in climate science; BS will be sorely lacking in yours!
Love the photo of the house, but was wondering why you chose full length pickets; and if that is a composite decking like Trex? Stay safe and healthy; we need you to continue writing for more ammunition in the war against ignorance and insanity!
Why full length pickets? Why not?
The deck is redwood, but after the recent fires I plan to replace it with fireproof Ameradeck. So many projects, so little time …
w.
Forgive my lapse, I neglected to say good design and excellent workmanship! I particularly like the polygonal sweep of the windows looking out on the deck!
The only reasons I prefer a bottom rail to capture the pickets is it makes sweeping the deck easier if you have a lot of tree litter,and I really hate stubbing my toe when I’m leaning on the rail; enjoying the view and a cold beverage! Cheers!
Given that we are talking about clouds, is it possible to separate the radiative effects from the vertical convective effects, especially of storm clouds in that tropical region?
Very nice analysis. The IPCC AR4 and AR5 both insist cloud feed back is significantly positive albeit uncertain. You show that clouds cool on average. A positive cloud feedback means them must cool less. That is conceptually physically possible in two ways. Less cloud—but ICOADS data shows no indication of that. Or the cloud ‘structure’ changes, for example more warming cirrus—but Lindzen’s adaptive iris paper shows just the opposite, in a fashion similar to your second set of figures. And adding adaptive iris to a climate model lowered its ECS significantly. Judith and I did back to back posts on that over at Climate Etc a few years ago. She interviewed Lindzen, I deconstructed the the new paper about the model.
Another strong reason to think the climate models are junk science filled with alarmist fudge factors like warming cloud feedback, as your recent post on models described.
“…climate models are junk science filled with alarmist fudge factors like warming cloud feedback…”
Very descriptive.
“This additional downwelling radiation leaves the surface warmer than it would be in the absence of the clouds.”
No it does not. Net heat transfer is driven by temperature differences, and always results in heat transferred from warm to cool, and NEVER EVER the other way around. Clouds can prevent some radiation from the surface from reaching space, thus retaining some extra energy in the atmosphere, but they cannot heat the surface by themselves. This is a vast over-simplification and leads to many mistakes such as the ridiculous Trenberth cartoon.
Yes, it does. I’m sorry, but your understanding of radiative heat transfer is incomplete. See my post “Can A Cold Object Warm A Hot Object” for a full discussion.
w.
Not according to Professor Smith, Engineering Professor of the Year at the Big U of Michigan.
Willis: “we find that almost everywhere on earth, as surface temperature increases, cloud cooling also increases (negative values)”
WR: So nearly everywhere on Earth there is a huge potential to cool when forcing rises.
It must be interesting to see the cooling mechanism at work during the summer seasons of both hemispheres: where and when forcing goes up, cloud cooling rises. A mechanism that is already visible by the displacement over seasons of the Inter Tropical Convergence Zone.
The same for the warming function of clouds: extending over larger areas during each hemisphere’s winter season and shrinking during their summer months.
When it gets ‘too cold’ warming clouds will be visible over larger surface areas and when it gets ‘too hot’ their cooling function will show up over larger areas. ‘Too cold’ and ‘too hot’ coincide with the ‘preferred range’ for most life forms, being adapted to a system that has been rather stable over hundreds of millions of years. Besides, all life forms knew the solution for occurring natural variability: migration.
Great post and very nice to see also the maps with the ‘Atlantic view’! They really add.
“all living together with us in our big old rambling house in the forest that I built with my own hands …”
I read badly nowadays. I understood you built a forest with your own hands. Oops.
Adrian Bejan asked for your email address. His is here https://mems.duke.edu/faculty/adrian-bejan
Thanks, Ian. He’s a long-time hero of mine, one of the best minds of the century yet generally unknown.
w.
I let Adrian know I posted this. You both are heros of mine
Thanks, Ian. I wrote to him. How do you know him?
w.
Earth has a fairly large atmosphere, which 10 tons per square meter. The large atmosphere
causes a lower daytime high temperature, but causes a higher global temperature, due to the atmosphere warming up. This is greenhouse effect before get into any effect from “greenhouse gases”.
The land ground surface can warm up to about 70 C whenever the sun is close to zenith and the air is warm. Though more commonly the ground warms to about 60 C and is preventing warming higher due to convectional heat loss to cooler atmosphere. The warmest land surface air gets is about 50 C.
Earth is 70% covered with ocean and since the ocean covers most of surface it dominates
the global surface temperature. And generally [due to weather effects} the ocean surface temperature can reach as high as 30 C. This largely due to partial pressure of H20, at 30 C
the partial pressure of water is 0.0419 atm when 30 C:
https://en.wikipedia.org/wiki/Vapour_pressure_of_water
At 40 C is it is 0.0728 atm. In terms of psi: .0728 times 14.7 = 1.07016 psi or compared
10 tons per square meter of atmosphere it is .728 tons per square meter. And indicates why one should put lid on pot, if want water to reach boiling temperature quicker. And why get a lot water vapor in a bathroom when you take a warm shower.
Similar to the atmosphere, the ocean causes lower daytime high temperature though increases the global average temperature- or if you like, a greenhouse effect. And the warm ocean kept Europe a lot warmer- the gulf stream is said to add about 10 C to Europe’s average temperature.
But I would say the ocean keeps the entire world warmer and one significant and well known way the ocean warms the entire world is that tropical ocean is the world “heat engine”. Near equator or tropical zone which is covers 40% of surface of the planet, get more than 50% of total sunlight reaching earth. And Tropical ocean is close to 80% of the tropical zone surface area.
Without the ocean {with less atmosphere- say less 5 tons per square meter} daytime high temperature could be much hotter, though night time temperatures could be colder. And without an Ocean, you don’t have a heat engine warming the rest of the world. The rest of world would have lower average temperature, though one could have higher daytime high temperature.
Anyhow, clouds are also a greenhouse effect, they generally increase average temperature and can lower day time high temperature.
It should be noted, that the ocean is warmed by both direct and indirect sunlight, and clouds can cause less direct sunlight and more indirect sunlight reaching the surface.
Some of the CMIP6 Chinese models and the 2 Russian models are actually very close to the Hadcrut4 observations, and as such project a much tamer warmer the 2100. Meanwhile, our two Canadian models are at the top of the worst performers. I wonder what the difference in cloud schemes might be between the models?
Hadcrut 4,5.6 are highly altered to promote global warming that does not exist.
With that in mind, all the models mentioned especially the Canadian’s, are useless. Consider that Canada destroyed 100 years of temperature data because it did not support the global warming theory.
According to Australian CSIRO models, the Nino34 region cooled by 0.8C in the 4 years between AR4 and AR5. In reality the temperature of the Nino34 region has no trend over the past 4 decades.
Climate models need to cool the past in order to maintain the warming trend. The groups responsible for the temperature records are complicit in this hoax.
Spectacular house young man. Yes young. We are both the same age
This is nonsense.
”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.”
Willis is claiming half the surface emitted longwave radiation returned to the surface by the cloud cover is keeping the surface warmer than in it would be under a full flux of short wave solar radiation.
And that’s just weapons grade bollox.
I didnt read any further because any conclusions drawn from such utter bollox can only be utter bollox.
Perhaps i should have read a bit further, my bad Willis
The reason the surface ”stays” warmer at night under cloud cover has nothing to do with back radiation, it simply loses far less energy to a cloud base that is +C than a clear sky with a cold sinc of minus -272C.
”’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. ”’
First, the earth radiates based upon its temperature. It doesn’t care if the sky @ur momisugly 3 K is in its way or if the atmosphere at 220 K is in the way.
Second, anything that intercepts the EM IR will, at best, radiate 50% of that downward, and 50% upwards. I say at best, because collisions of CO2 with other N2/O2 molecules will remove radiation from the equation. Then energy loss by convection and the lapse rate takes over and not radiation.
Thirdly, The net radiation between the earth and the sky/clouds is always toward the sky/clouds. If the earth is radiating upward 10 W/m^2 and clouds radiating downward at 5 W/m^2, the net is still 5 W/m^2 away from the earth. It is then incorrect to say that clouds warm the earth. What happens is the gradient over time is reduced which means the earth does not cool as fast. A cold body simply can not transfer net heat to a hotter body, it is that simple.
Lastly, what can happen during the day is that condensed water vapor, i.e. water droplets, or in other words clouds, can absorb EM near IR directly from the sun and become water vapor once again. That limits the near IR reaching earth. As evidence, think of what burns off fog. It isn’t visible light. It isn’t back radiation from CO2. It is near IR being absorbed by H2O.
+288
Chuckle!
So you you built the forest with your own hands.
Very industrious 🙂
Here’s my take on clouds: They create a shadow on the ground, which means that they act as a barrier to the light/heat from the Sun.
Therefore, this sentence: {The general claim from mainstream climate scientists and the IPCC is that the clouds will increase the warming, viz: ] means (to me) that the so-called general claim by so-called mainstream climate scientists and their buddies at IPCC do not leave the building to find out for themselves exactly what does happen when a cloud comes between the Sun (heat and light source) and the Earth (absorbs whatever Sol hands out).
A simple experiment on a sunny day that is also partly cloudy can support the statement that the cloud blocks both the light and heat of the Sun. I guess that means that, come summer, I will have to buy a thermometer and put it on a tripod, and go find a spot where there is plenty of sunlight being blocked by cumulus and altocumulus clouds, just to prove that I’m right and the desk jockeys are incontrovertibly wrong.
Since it’s supposed to snow today and the temps right now reflect that (low 30s), I will wait until we really to get to summer, go to the beach on a partly cloudy day and shoot pictures of the thermometer “with clouds” and “without clouds”. That should settle that issue.
I’ll pick a good day for it, and take a picnic lunch with me.
A very interesting number: per one degree Celsius there is extra cooling for the ‘average globe’ of 4.3 W/m2 (figure 3 and 4).
For ‘double CO2’ it is estimated that the radiative effect of CO2 is 3.7 W/m2 or about one degree Celsius of initial warming.
Combining the two, the initial one degree of warming for double CO2 will result in 4.3 W/m2 extra cloud surface cooling.
Conclusions:
I would guess the cooling may be less, as the time span is short and his previous evaluation with end point in 2017 resulted in 0.0 W/m2 cloud feedback.
removing this
“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”
It simply is not possible for clouds to add to warming because we would end up in a run-away warming event. Since the Earth has never experienced run-away warming (at least since life began) and has had higher carbon dioxide levels this proves clouds cannot produce a net warming unless you also speculate that it is somehow capped at some speculative upper-bound temperature. Then you have the problem of how does anything ever cool off to produce glaciers again.
Clouds are the visible part of an energy balance engine that keeps Earth’s temperatures tightly controlled. Through physical state conversion of water and convective movement of air it works harder when temperatures rise to vent heat out of the atmosphere.
I was thinking how appropriate the science in this post is for publication when I arrived at the point where you said that’s what you are considering. I agree with you about the difficulty of writing for the scholarly literature. (I’m going through that process now.) There’s also the problem of page charges. (That’s why 2 of my earliest papers were published by Nature–which did not charge page fees way back then.) The bottom line is that my published papers have opened doors that would have remained forever closed. So, I encourage you to consider a paper based on this post.
Good post. I hope that you do get to publish. I’ve often wondered how the exhaust of hot water vapor from hydrocarbon combustion affects the atmosphere, I feel that it has been neglected since Ahrennius, and I think that your work will be essential to understanding that factor in the chaotic, complex climate system.
Water vapor from hydrocarbon combustion is tiny compared to water vapor from increased irrigation https://www.researchgate.net/publication/338805648_Water_vapor_vs_CO2_for_planet_warming_14
The atmospheric window closes to sunlight when the water surface reaches 32C; cyclic cloudburst with perpetual cloud. Surface temperature is regulated to 30C by cloud and moisture convergence from nearby surface at 28C that is absorbing the majority of the heat input.
Clouds will be whatever is needed to regulate the temperature to 30C. It is a process that works across three tropical oceans.
Hotter oceans during the Cretaceous have been attributed to lack of clouds due to fewer biological condensation nuclei, resulting from high surface temperatures. A vicious circular, positive feedback loop.
Amplification of Cretaceous Warmth by Biological Cloud Feedbacks
Lee R. Kump1 * and David Pollard2
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.922.1372&rep=rep1&type=pdf
Submarine volcanism during the rifting apart of Gondwana and continued seafloor spreading of the Central and North Atlantic may have gotten the heat on to start.
It is possible to get larger warm pools not not possible to exceed 30C for more than a cloudburst cycles; about 24 hours. The only exception is the Persian Gulg where convective instability is rare.
The linked paper is based on models and we know how reliable they are. There are far better reconstructions that show tropical warm pools do not exceed 30C.
John Tillmann: “Hotter oceans during the Cretaceous (…) resulting from high surface temperatures”
WR: Apart from the circular reasoning by the authors of the article, there are always cooler places on Earth (closer to the poles) where biological condensation nuclei still can be / could be produced and where condensation will take place at known altitudes. And if not near the surface those places to condense are found higher in the atmosphere because of stronger cooling. Salt (from oceans, wind and waves) also acts as a condensation nucleus: “If a sea salt particle is introduced into an atmosphere of sufficiently high relative humidity, the particle will grow to a droplet by condensation of water vapor.” https://apps.dtic.mil/dtic/tr/fulltext/u2/014994.pdf.
Evaporative surface cooling will continue at known surface temperatures as long as there is water in the oceans. And so ocean surface temperatures will remain maximized. As they have always been.
Is here really a single climate phenomenon called “clouds”. That do anything – either heat or cool? Isn’t it the case that tghere are at least four different types of clouds in general, and that they all occur at differing altitudes? and that clouds at differing altitudes have differing effects on incoming and outgoing short- and long-wave energy flows?
Can those different types of clouds be accounted for in a single model of the future and just be “clouds (undifferentiated)”? and then those undifferentiated clouds be counted on to produce a certain pre-identified and quantified effect?
It may be that way . . . . but I don’t think so.
Kip, I wrote a partial empirical answer to your explanation in essay ‘Models all the way down’ in ebook Blowing Smoke. I compared two actual sat based cloud observations to 6 models of those same clouds over the same hindcast period over the same surface. There was essentially zero correspondence of either cloudiness or cloud type as measured by top height temp.
Rud ==> I have the Kindle version of your book, and will re-read the section on clouds to remind myself of the details.
The ability to programmatically create “pretty pictures” from crappy un-physical data has ruined many fields of science and is a real temptation for far too many otherwise good minds.
Part of the reason I wrote that piece “Throwing Out the Numbers“….
NASA admits that the net effect of clouds is to cool, although GIGO model parameterization by computer game programmers don’t give them their due.
https://climatekids.nasa.gov/cloud-climate/
“Clouds within a mile or so of Earth’s surface tend to cool more than they warm. These low, thicker clouds mostly reflect the Sun’s heat. This cools Earth’s surface.
“Clouds high up in the atmosphere have the opposite effect: They tend to warm Earth more than they cool. High, thin clouds trap some of the Sun’s heat. This warms Earth’s surface.”
NASA also says that “climate scientists” predict more warming will cause fewer clouds, thus further warming, a positive feedback. This forecast is strange, since warming is supposed to produce more water vapor in the air.
“Clouds are said to be the largest uncertainty in climate models, and I can believe that.”
I remember a couple of decades ago while nesting several “If-Then” (conditional) statements in an Excel spreadsheet, I learned the hard way that you have to be very careful the order you place them in to get the correct, that is an accurate result. The first time the condition is satisfied (comes back “TRUE”) the rest of the conditions in were formula ignored.
It seems that in climate modeling, “Man’s CO2” is way too often the first “condition” in their models. “Clouds” and “Natural” come last.
PS I’ve always liked how you refer to your wife as “my ex-fiancée”. 😎
“I calculated the changes in the net CRE with respect to surface temperature for each 1° latitude x 1° longitude gridcell.”
How is that achieved?
Linear regression of the two monthly 20-year datasets (CRE and temperature) for each gridcell.
w.
So I assume your increasing cloud cooling effect with a rising surface temperature would imply increased low cloud cover. Surely low cloud cover has declined since the mid 1990’s?
My frame of reference is that ENSO and the AMO act as negative feedbacks to net changes in climate forcing, and they control low cloud cover and amplify the warming or the cooling. Such that post 1995 AMO warming is the response to a decline in indirect solar forcing, via the northern annular mode, which is then self amplified by the reduction in low cloud which the warmer SST’s drive.
A good guess would be to argue well if the clouds cool the tropics, then if earth gets warmer other areas start to get a closer temperature to that of the tropics so in theory will start behaving more like the tropics.
I mean if you start in the tropics that have the negative cloud feed back and move a few hundred miles north or south, what is the difference? Is it mainly temperature or sun position that starts to dampen the negative cloud feedback? Something is causing it.