Guest Post by Willis Eschenbach
Apparently I must be a glutton for punishment, because here I am in the arena once again, discussing the results of my research and preparing for the insults and brickbats.
However, there’s no place I’d rather be—I’m a Teddy Roosevelt man. He famously said:
“It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better.
The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again, because there is no effort without error and shortcoming; but who does actually strive to do the deeds; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of high achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid souls who neither know victory nor defeat.”
But I digress …
The earth’s climate is an energy flow system that on average is approximately at steady-state. At steady-state, the amount of energy absorbed by each part of the system is equal to the amount of energy lost by that part of the system. If this were not true, the affected parts would be continually either warming or cooling.
And this is true of the earth’s surface. It basically loses as much energy as it gains, and as a result, the earth’s surface temperature over the 20th century was stable to within less than one percent.
Let me start this perambulation with the fact that not all of the energy flux absorbed by the surface is converted to surface temperature and lost to thermal radiation. Some of the energy flux is lost as “sensible” heat, heat we can feel, through conduction to the atmosphere and convection away from the surface. And some is lost from the surface as “latent heat”, meaning it is heat removed by evaporation at the surface. After those losses, the energy that remains heats the surface and is lost as longwave upwelling radiation from the surface.
Figure 1 shows the relative amounts of energy absorbed and lost by the surface.
Figure 1. Energy budget of the surface, showing energy gained (longwave and shortwave) and energy lost (as longwave radiation and as latent/sensible heat.) Since the planet is at a steady state, gains and losses are ~ equal.
Now, suppose that we want to raise the surface temperature of the earth by 1°C. How much additional energy flux will be necessary to maintain that new warmer steady-state?
Well, since at steady-state we need gains to equal losses, we need as much flux as the additional amount of energy flux that will be radiated at the new higher temperature. Using what is known as the “Stefan-Boltzmann Equation”, we can calculate that we need a minimum of an additional 5.5 watts per square meter (W/m2) of energy flux to raise a blackbody at the earth’s temperature by one degree Celsius. (It’s a minimum because the percentage of latent/sensible heat loss increases slightly with increasing temperature, but we can ignore that in this analysis.)
However, we also need to note that from Figure 1, only about 78% of the absorbed energy flux is converted to temperature and lost as radiation. So including latent/sensible heat losses we’ll need 5.5 / .78 ≈ 7 W/m2 of additional total energy flux absorbed by the surface to raise the surface temperature one degree.
Now, consider the mainstream IPCC position, that a doubling of CO2 will increase downwelling longwave at the “top-of-atmosphere” (TOA) by 3.7 W/m2. This means that if you instantaneously double the CO2, the amount of longwave escaping the planet at the top of the atmosphere will be reduced by 3.7 W/m2.
And this additional 3.7 W/m2 of downwelling radiation from the CO2 doubling is claimed by the IPCC to increase the surface temperature by 3°C.
Bottom line? According to the IPCC, it only takes ~ 1.2 W/m2 of additional TOA forcing to increase the surface temperature by 1°C.
So here is the serious question I alluded to in the title …
How does a top-of-atmosphere CO2 forcing of 1.2 W/m2 mysteriously turn into the 7 W/m2 of additional surface energy flux that we need to warm the earth by 1°C?
The IPCC folks wave their hands and vaguely allude to “cloud feedback” and “water vapor feedback” increasing the downwelling IR from the top-of-atmosphere to downwelling IR at the surface.
But this would require that the feedback amplify the original signal by a factor of almost six … and my understanding is that a feedback factor greater than one leads to runaway.
So my question remains:
What mysterious force is changing the 1.2 W/m2 of CO2 TOA forcing, the forcing that the IPCC says will raise the surface temperature by 1°C, into the 7 W/m2 of surface absorbed energy flux that is actually necessary to raise the global temperature by 1°C?
All serious answers welcome.
My best to all,
w.
Footnote: The idea that cloud feedback is positive is quite unlikely. First, Le Chatelier’s Principle says that if a dynamic equilibrium (a steady-state condition like the climate) is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change to reestablish an equilibrium.
Next, the claim of a net positive cloud feedback is contradicted by the CERES data. Here’s net cloud radiative effect (CRE) versus temperature on a gridcell by gridcell basis.
Figure 2. Net cloud radiative effect (CRE). This is the change in downwelling radiation in W/m2 when clouds are present. It includes both the longwave and shortwave effects. Below the horizontal line the net effect is cooling.
The slope of the yellow line indicates the direction of the cloud feedback. If it cools more with increasing temperature (negative feeback), the slope goes down to the right. And if the feedback is positive, if it cools less with increasing temperature, the slope goes up to the right.
In the tropics, about 40% of the planet, the feedback is extremely negative, the slope goes almost vertical. And from -15°C to 15°C, another 33% of the planet, the feedback is also negative.
So it doesn’t seem the answer to my question is “cloud feedback”.
Of Note: As with my previous two posts, I am examining the ramifications and the mathematics of the greenhouse effect. If you think the greenhouse effect violates physical laws, read my two posts, People Living In Glass Planets, and The Steel Greenhouse. And if after reading them, you still think the GH effect doesn’t exist, or that downwelling radiation doesn’t exist, or that radiative energy fluxes don’t add, then please, go away. Don’t go away mad, in fact you are welcome to continue to read the comments … but this is NOT the thread to dispute downwelling radiation or the greenhouse effect. Those subjects tend to totally threadjack the thread to an inane endless discussion that settles nothing, and I’m not interested in that. Please take those and related subjects to some other thread.
I’m interested in a serious answer to my question about how it’s supposed to work, how 1.2 W/m2 at the TOA is converted into 7 W/m2 at the surface, and where that extra energy is allegedly coming from.
MATH: The change in radiation from a 1°C temperature change of some object is given by the differential of the Stefan-Boltzmann equation:
dWdTC = function(c,epsilon=1) 2.27 * 10-7 * epsilon * (c + 273.15)3
where c is the temperature in degrees and epsilon is emissivity. In a steady-state condition where average losses are equal to average gains, this is also the amount of additional energy needed to raise the object’s temperature by 1°C. As is customary in this kind of analysis, and because the emissivity of the earth is somewhere above 0.95, for simplicity I’m using epsilon = 1.
My Usual: Please quote the exact words you are discussing in a comment so we can all follow your train of thought.
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Willis,
Pleased to see you tackling this matter.
On WUWT, 2020/09/11, I listed a dirty dozen questions for climate change aficionados.
They included:
For a 1⁰C change in global temperature –
2 By how many ppm does atmospheric CO₂ change?
5 By how many sq km does the average area of cloud cover change?
8 By how many Watt per square metre does the Top of Atmosphere TOA radiation balance change?
10 By how much does total precipitable rainfall TPW change?
Very few of the dozen questions were able to be answered. Maybe I phrased them poorly, but to me they seemed to encapsulate the big test of the “settled science” type of claim by the Establishment. There is much claimed about the disasters that will arise from a change of global temperature, yet these basic questions are far from settled.
You are, thankfully, making progress. Geoff S
Thanks, Geoff, appreciated.
w.
A serious question, surely 508W/m^2 equates to a surface temperature of 310.5K (emissivity 1) or 307.5K (emissivity 0.96)?
https://www.spectralcalc.com/blackbody_calculator/blackbody.php
No, because something around 100 W/m2 is lost as latent or sensible heat, leaving only 400 W/m2 to maintain the surface warmth.
w.
It is not all lost, some returns to the surface as longwave radiation. The biggest error is in averaging the solar shortwave globally, do that for the Moon and its global temperature is nearly 70°C too warm.
” What mysterious force is changing the 1.2 W/m2 of CO2 TOA forcing, the forcing that the IPCC says will raise the surface temperature by 1°C, into the 7 W/m2 of surface absorbed energy flux that is actually necessary to raise the global temperature by 1°C? ”
— From the falling rH, I calculate the quantitative lack of evaporation over land areas that man has caused through land use changes over the millennias.
Another reason for the decreasing rH lies in the vegetation itself, which closes the stomata during drought stress.
1% of declining rH correspond to a lack ~6800 km³/y of evaporation on land areas(10%). 4624PWh/y are converted into sensible heat flux and LW radiation.
” What mysterious force is changing the 1.2 W/m2 of CO2 TOA forcing, the forcing that the IPCC says will raise the surface temperature by 1°C, into the 7 W/m2 of surface absorbed energy flux that is actually necessary to raise the global temperature by 1°C? ”
— From the falling rH, I calculate the quantitative lack of evaporation over land areas that man has caused through land use changes over the millennias.
Another reason for the decreasing rH lies in the vegetation itself, which closes the stomata during drought stress.
1% of declining rH correspond to a lack ~6800 km³/y of evaporation on land areas(10%). 4624PWh/y are converted into sensible heat flux and LW radiation. 7W/m² evapotranspiration on land correspond to 12880 km³.
https://climateprotectionhardware.wordpress.com/
Okay, no comments please says me, W.E.?
The 7x amplication is truly wrong and has been accepted by most posters here as erroneous. Pat yourself on the back.
Barry, if you wish to be taken seriously, please demonstrate (not claim but show) EXACTLY where my math is wrong. Please show your math, and quote my words that you think are incorrect.
w.
A serious answer to a silly question – it is all to do with climate phiisics. This branch of phiisics can do whatever the programmers want it to do. It has no meaning in the observable world.
If you want to really understand what is happening then you need to use observable physics.
If you want to know why the Northern Hemisphere is warming up and the Southern Ocean and Antarctica are cooling then you need look no further than the precession cycle. There is no “global warming” as the attached shows. Some parts of the globe are cooling, some parts of the globe have zero trend and some parts are warming.
The April solar intensity in the Northern Hemisphere has been increasing for 5,000 years and the changes are not insignificant in human scale as this table shows for 30N:
-1.000 373.489453
-0.900 373.872773
-0.800 374.258234
-0.700 374.645437
-0.600 375.034002
-0.500 375.423566
-0.400 375.813785
-0.300 376.204330
-0.200 376.594883
-0.100 376.985132
0.000 377.374769
0.100 377.765110
0.200 378.154160
0.300 378.541432
0.400 378.926421
0.500 379.308615
0.600 379.687501
0.700 380.062572
0.800 380.433341
0.900 380.799342
1.000 381.160145
Outside the tropics, the lag between solar EMR and ocean surface warming is observed to be two months. The atmospheric response over oceans adds another month. The land temperature lags solar EMR by one month. So April and May solar EMR increase will be driving the observed boreal summer temperature. Outside the tropics, the temperature response of most land to EMR is twice that of most ocean. The NH has higher proportion of land than the SH so the gradual shift in solar peak intensity northward due to precession is increasing the intensity over land compared with water so the average surface temperature has to rise.
September solar EMR at 30N is declining, not as much as April is increasing, but that means the northern winters will be getting cooler with presently an overall upward trend.
Earth’s climate system has two powerful mechanisms for retaining heat. The most readily observed is the formation of sea ice that provides an insulating layer on oceans. The other is the loss of convective instability below surface temperature of 15C. Below 15C, the clouds become dull and lifeless but they prevent considerable heat loss from ocean surface cooler than 15C. They are a damping factor on the rate of cooling of oceans.
If you have the opportunity to observe ocean surface around 13 to 15C you will be able to observe this transition from dull and lifeless clouds to fluffy and lively.
The attached shows the proportion of ocean surface at particular temperature for various months.
The convective transitions are evident in this data. Below 15C the atmosphere can fully saturate. That prevents heat loss by reducing latent heat transport from the ocean surface. Above 15C, the atmosphere can form an LFC resulting in convective instability that causes cycling between clouds and clear sky. Above 22C, the atmosphere can fully saturate the zone above the LFC and so-called deep convection can exist. 24C to 28C are usually strong mid-level divergence zones where most of the energy uptake occurs due to the persistence of clear skies. 30C is the limit where the surface energy flux is in balance in open water (away from the influence of more powerful convective towers over land) due to the increase in cloud persistence over 30C warm pools
Anyone with observational ability can actually see these transitions if they have the opportunity to visit locations covering the range of temperature from about 12C to 30C..
A doubling of CO2 is (per se) meant to DECREASE OUTGOING radiation TOA by 3.7W/m2. And btw., outgoing radiation is all that matters!
What?! Those 3.7W/m2 should mean 1-1.2K in warming (excluding feedbacks)
Again, “back radiation” (BR) is irrelevant. But for those who have issues how the numbers would add up, let me explain this. Per se a doubling of CO2 would decrease emissions TOA by said 3.7W/m2. Including overlaps and other things, it is only 2W/m2. BR would increase by similar magnitudes, although it does not matter. As the atmosphere warms, as less radiation is emitted TOA, a warmer atmosphere will provide more BR (which is a function of temperature), independent of the primary CO2 “BR effect”.
Eventually there will always be enough BR to settle accounts with any given temperature, because BR is a function of temperature, not the opposite.
E. Schaffer September 5, 2022 6:11 pm
E., you’re missing the other half of the story. If outgoing radiation is decreased by 3.7 W/m2, what happens to it? It doesn’t disappear.
In fact, it is redirected back down to the earth. So no, outgoing is NOT “all that matters!”.
w.
In order to compensate, the “planck feedback” comes into play, meaning the temperature at emission level must increase accordingly.
101 climate science..
“A doubling of CO2 is (per se) meant to DECREASE OUTGOING radiation TOA by 3.7W/m2.”
This is correct, but only for the portion of outgoing radiation emitted from the TOA.
The total sum of outgoing radiation stays the same(approx. stationary system) . Therefore, the part of the ground surface radiation that reaches space directly must increase by 3.7W/m^2.
The total amount of radiation from the ground surface a) increases by
b) the part that goes into space directly plus
c) the part that is absorbed/reflected by the atmosphere (greenhouse gases and clouds).
Delta_a = b+c
b = 3.7W/m^2
Delta_a/b = 0.6
Delta_a = b/0.6 = 6.2W/m^2
This means the ground surface emission increses by 6.2W/m^2 if the TOA emission decreases by 3.7W/m^2
No
Willis,
Have you read the paper by W. A. van Wijngaarden and W. Happer entitled “Dependence of Earth’s Thermal Radiation on Five Most Abundant Greenhouse Gases”? It is available at
https://arxiv.org/pdf/2006.03098.pdf
and predicts that a doubling of CO2 levels would lead to an increase in temperature of 2.3K assuming a constant relative humidity. All of the details about the radiative transfer that you are asking about are there. And the IPCC is not involved at all.
A. There is No Urgency to Act Now and Thus There is No Need for the Proposed Rule Our informed scientific opinion is that doubling CO2 concentrations will cause about 1 C or less of warming. But assuming that doubling CO2 levels from today’s 415 ppm to 830 ppm will raise temperatures by a “dangerous” 2° C (about 4° F), which is unsupported by science, it would take a century or more for that to happen at the levels of CO2 emissions today. Willima Happer and Richard Lindzen April 11, 2022
Happer-Lindzen-SEC-6-17-22.pdf (co2coalition.org)
Willis (and Anthony) and others….Please don’t stop posting and explaining to those of us “uneducated” in the science of climate. Some may point out opposition to your writings, which is also interesting to read, along with the rebuttals…but this forum is fantastic to so many of us, who have education in other fields of engineering/science/social studies. Some if this may not be simplified to our education level, we read and gain more with every posting.
Bring it on!!
Thanks, Deacon. Unlike many, you seem to have noticed what WUWT actually does—provide a forum for public peer review. See my post “A New Year’s Look At WUWT“.
w
Deacon, hang in there. Probably most of us reading today began as “lookers” as it was called 13 or so years ago. Seems I have now spent half my life since then trying to quench my insatiable quest to learn more!
WUWT=love/hate relationship. Greatly increased understanding of physics vs less sleep pondering the physics and researching same.
Ultimately it still seams to me that night time will transport away any additional small amounts of heat on a daily basis preventing any “run away warming” just using basic thermodynamics combined with a mixing swirling flowing atmosphere.
Hot air up. Hot moves to cold. Heat is gone before it can accumulates. Even with a few additional “magic molecules in the atmosphere. Heat in equals heat out. Too simple ,to intuitive ?
The head posting here asks “I’m interested in a serious answer to my question about how it’s supposed to work, how 1.2 W/m2 at the TOA is converted into 7 W/m2 at the surface, and where that extra energy is allegedly coming from.”
Well, we’ve had all kinds of discussion, both on WUWT and other places, about how tremendous and overwhelming the power of “back radiation” can be, with the atmosphere sometimes even described as being nearly opaque to IR (another way of saying that most of the IR surface emission can come back as back radiation, boosting the IR surface emission that you have to have in the first place).
I’m not saying that I find any of your mentioned numbers on this to be plausible, or that I trust any standard theorists to tell me that this exact numerical effect is quantitatively correct.
It’s just that this powerful ‘back radiating’ property of the atmosphere is the answer they always give?
And it has proven to be a very good answer for the vast majority of gullible people.
NASA employed the late physicist Michael Mishchenko to come up with a means of determining Earth’s energy balance. On his way to a proposal he had to destroy the notion of back-radiation. I am not sure he achieved that within GISS before he passed but he did propose a solution to measure the energy balance. Set out in this paper:
https://opg.optica.org/viewmedia.cfm?r=1&rwjcode=josaa&uri=josaa-33-6-1126&seq=0&html=true
My bolding to make the point that any notion of using S-B relationship for anything occurring in Earth’s atmosphere is “outdated notions”. That is a kind way of stating it is BS.
Well, alright, more technicalities, physicist Michael Mishchenko appears to have been questioning the measurements, or calibration of measurements, putting in his own suggestion for how to measure infrared radiation correctly.
I’m not sure from your reference whether this really does away with the ‘back radiation’ concept — it looks like more a question mark on whether the amount of any such effect is currently known?
And, no small part goes into the mass of photosynthetic organisms that provide food for all the rest of life on Earth.
True … but that heat is returned by the decaying of the organic matter, so no net loss to the surface.
w.
Ultimately, everything is recycled. The thermohaline circulation may keep oceanic organic material sequestered for about a thousand years. Permafrost may keep organic matter sequestered for a couple million years. Oil and gas are derived from organic matter sequestered for tens of millions of years. Limestones created from the shells of calcifiers may isolate the products of work done through photosynthesis for hundreds of millions of years.
Some years ago I read some articles about the “evolution” of the “water vapour feedback” theory. (Unfortunately I do no have the references now, but I am sure it can be found again).
My understanding:
When IPCC was formed the first task was to estimate how much earth had warmed, and how much of the warming that could be attributed to CO2. A group of scientists came to the conclusion that the CO2 increase could only explain about a third of the warming.
They said something like this : ” IF all the warming should be explained by increased CO2 there must exist some kind of amplification factor around 3″.
This was later transformed to: ” Since there is an amplification factor around 3 all of the warming is due to the increased CO2″.
IPCC logic.
“How does a top-of-atmosphere CO2 forcing of 1.2 W/m2 mysteriously turn into the 7 W/m2 of additional surface energy flux that we need to warm the earth by 1°C?”
You´re not even ashamed of creating 5.8W/m^2 worth of energy from 1.2W/m^2?
Why do you not have a first law analysis? The first law says ΔU=Q-W, and such an analysis is the first thing you do when analysing a thermodynamic system. But you don´t even include work? The amount of work done by a system is subtracted from the heat flow, and it´s very easy to see how much it is.
TSI/4 would be the emitted energy by a perfect blackbody, no work will be done in that case. But Earth emits Q=σ255^4, so the rate of work being done will be (TSI/4)-σ255^4=101W/m^2. So:
ΔU=TSI
Q=σ255^4
W=(ΔU/4)-Q=101W/m^2
The difference between the perfect blackbody and the effective emission temperature is the work done by the system, 101W/m^2. This energy is “lost”, converted into work, and will not be emitted because work cools a heat engine.
Your whole calculation is invalid because you don´t have a first law analysis.
But surely that work is turned into heat energy quite quickly?
The exception that I can think of is energy stored as increased mass of plant and animal tissue, due to increased photosynthesis.
But I doubt that is anything like 101W/m^2.
Work done by weather ends up as heat quite quickly i would’ve thought.
Thanks, kzb, you beat me to it. The work done by solar energy is the movement of the atmosphere and the ocean. Turbulence rapidly turns that back into heat.
w.
You show ~340W/m^2 from the atmosphere. This is a violation of the laws defining emissive power. The atmosphere is 255K, the maximum emission from a perfect blackbody at that temperature is ~240W/m^2. That is the MAX. You´re breaking the physical laws for heat radiation, it´s impossible to get 340W/m^2 at that temperature.
Some of the radiation goes from the surface directly into space. Only a part is transported through the atmosphere
Dear Willis, thank you again for a stimulating post.
I’m not sure I agree with your comment “It’s a minimum because the percentage of latent/sensible heat loss increases slightly with increasing temperature”. The rate of evaporation of water rises steeply with temperature. By my back of an envelope calculation, if the oceans warm 1°C the rate of evaporation will rise by 10%. If the current latent heat losses are around 72W/m^2 then a 10% increase shouldn’t be ignored.
Ramanathan explained this 40 years ago. Wonder if it’s still valid.
https://journals.ametsoc.org/view/journals/atsc/38/5/1520-0469_1981_038_0918_trooai_2_0_co_2.xml?tab_body=pdf
There is much work involved for example in ocean currents.lacking other sources, the energy input to drive currents is likely to come from the sun. It the ocean currents speed or slow, there is a different balance that affects the assumptions of a near equilibrium state. The effect might be small, but it takes time to happen. This introduces the topic of page. The current argument is largely based on radiative in versus out measured over a decade or so. The measurements are also oner short periods and they have the old problem of the stresses on uncertainty from subtraction of two large numbers to find a difference that is hopefully within the real uncertainty bounds. These various factors combine to introduce doubts that might be summarised by a question like “how can we know that we are looking at a long term, climate-related state of affairs and not a snapshot of a change taking place?”
That said, I do not imply criticism of Willis for presenting this analysis. Without such inquiry of the science, progress is stifled. One has to start somewhere. I am particularly captivated by the Willis scattergrams and the way their pictures are a thousand words. But I am troubled by various uncertainties in this article. Geoff S
consider the mainstream IPCC position, that a doubling of CO2 will increase downwelling longwave at the “top-of-atmosphere” (TOA) by 3.7 W/m2. This means that if you instantaneously double the CO2, the amount of longwave escaping the planet at the top of the atmosphere will be reduced by 3.7 W/m2.
And this additional 3.7 W/m2 of downwelling radiation from the CO2 doubling is claimed by the IPCC to increase the surface temperature by 3°C.
Bottom line? According to the IPCC, it only takes ~ 1.2 W/m2 of additional TOA forcing to increase the surface temperature by 1°C.
You’ve assumed direct proportionality between temperature and CO2 concentration.
Whereas it is a logarithmic relationship.
I did NOT “assumed direct proportionality between temperature and CO2 concentration”. I said a “doubling of CO2 will increase downwelling longwave at the “top-of-atmosphere” (TOA) by 3.7 W/m2.”
That is a log rather than a linear relationship.
w.
Well it looks like it, because you said if 3 degrees corresponds to 3.7 W/m^2 then 1 degree corresponds to 1.2 W/m^2. You are saying downwelling radiation is directly proportional to CO2 concentration or something very close to it.
No Willis said that temperature was linearly proportional to ‘downwelling radiation’ and that ‘downwelling radiation’ was proportional to the log of CO2. So he’s assumed a log dependence of temperature on CO2.
Willis – “First, Le Chatelier’s Principle says that if a dynamic equilibrium (a steady-state condition like the climate) is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change to reestablish an equilibrium.”
A nitpick here is that where there are lags in the responses to that disturbance, you’ll likely overshoot the new equilibrium situation and get an oscillation. Depending on the responses, that oscillation may be damped, and given enough different responses to the disturbance (in a complex system) each with a different time-constant and damping-factor, the result of a disturbance might be very complex.
However, the thing that stands out to me about the climate is the stability over time, providing you use an average over 30 years or so. To me, that points to an overall strong negative feedback in the system, since a 1°C variation over a period of 150 years or so is only around 0.3% variation in absolute terms, and that’s if you accept that the averaged temperature measurements 150 years ago are accurate to 0.01°C anyway. That’s despite the actual energy input we get from the Sun varying by at least 3% because of orbital mechanics, and the sunspot cycle varying the spectrum of energy received on around an 11-year cycle.
A while back you put up a post “where’s the climate emergency?” which explored the question over a long timescale, and another looking at CO2 levels versus temperature over the last 67 million years or so, which should have been conclusive that there’s no cause to worry.
Though the change in downwelling LWIR as CO2 changes is measurable, and must have some effect, it looks to me that Le Châtelier’s principle applies here and the net effect on average temperature is reduced from what we calculate it ought to be. For me, looking at the graph of “average world temperature” since 1850 compared to the CO2 concentration, which only really started to rise significantly around 1950, does not show any significant effect of CO2 on temperature, though CO2 increase obviously has an effect on plant growth.
Most of the people I know are however obsessed with “reducing CO2 emissions to save the planet”. Though I’ve pointed them at your posts, they receive daily propaganda about the Climate Catastrophe backed by what appears to be a consensus of distinguished scientists and naturalists (no, no naturists AFAIK).
Since I can’t answer your question of how 1.2W/m² gets translated into the 7W/m² necessary to raise the temperature by the amount the IPCC says, maybe I can ask you a question instead. What’s the best way to persuade people that CO2 emissions are not a danger, and that there’s no Climate Emergency, and that the local weather has always been changing so our best option is simply to adapt as we’ve done in the past? My tactic has been to show them the data, and that the climate changed (and either destroyed a civilisation or made it possible, depending on which way it went) long before the industrial era or SUVs. So far, it hasn’t changed their belief that this time it’s because of our use of fossil fuels. Then again, it’s always hard to change beliefs.
As Mark Twain has said: It’s easier to fool people than to convince them that they have been fooled.
It’s within the human DNA …
Your calculations produce a similar result to the paper “The Impact of CO2 and H2O on Equilibrium Earth Temperatures” http://www.ijaos.org/article/298/10.11648.j.ijaos.20210502.12
where the result is derived from the HITRAN IR absorption spectra of atmospheric gases.
Willis,
You put your finger nicely on the cruxt of the issue: How to measure and model the heat engine that is our biosphere. As we have all seen from the various models on offer, the results are (speaking softy) incomplete. And as Kip Hansen’s recent dust-up shows, quantifing the amount of heat in even a modest slice of the biosphere is a dicey proposition. It’s apparent that the current state of the data is woefully inadequate.
Regarding the use of transfer functions (the bulwark for feedback and sensitivity analysis), they are for the most part impirical. The boundary inputs/outputs are measured and transfer functions derived (ok, curve-fitted to models with some semblance to physical reality). If one studies any of the books on feedback (and even feed-forward) control design, the methods are well established and often useful.
One major deficiency in the current application of the impirical approach is no one has measured the relationship between inputs/outputs under dynamic conditions. Chemical engineers will undertake a step-change to an input and then measure the resulting response in the outputs. They can then derived lead-lag parameters for the various transfer models frequently used. Electrical engineers will interogate their system with a sine wave input and measure the output. Then, they relate the input to the output in a frequency response and produce those nice Bode plots and Nyquist diagrams.
Now, it is apparent that mere mortals can’t vary the heat input to the planet to characerize that dynamic response. It would be incorrect methodology to use CO2 forcing for this purpose. In terms of a transfer function, CO2 is a parameter and not an input to the system. Characterizing any change with CO2 (a time-variant value) is characterizing the first derivative behavior of that parameter and not the dynamic behavior of the overall system. A useful undertaking for the robustness of the transfer function, but that doesn’t correct our first deficiency.
Further, control engineers are under no illusion that the transfer models are complete or widely reliable across the range of operating parameters even for the applications for which they were derived. That is, they’re reliable only over the range of input/output values used to derive them. Yes, one can then extrapolate beyond that range, but the prudent designer take steps to keep the system in control (damped response tuning, limiting controlers, cascaded control loops, etc.). They keep a brightline separation between the control models and reality.
Back to your question: how can the descrepancy be justified? In the ways and methods you have repeatly demonstrated (frankly of any careful worker), it can’t be. If this was a strictly physical, deterministic model, it would be an immediate show-stopper.
However, in the transfer function modeling relam, this is not actually a problem. Transfer fuction modeling is used so that the pesky physics of the system (clouds, wind/water curents with their seasonal/decadal osscilations, etc.) can all be glossed-over and rolled-up into an impirical model. It is merely regretable that the dynamic parameters have not been properly determined. The deficiencies of the input/output data can be swept-aside with some statistical analysis. Since it’s all made-up, your questions falls before this march of poorly considered rationalization.
“Get your facts first, and then you can distort them as much as you please.”
Willis – wonderful, thought provoking article, as usual.
I have a question if I may, and perhaps a topic for a future piece…..
If most of the IPCC climate models are claiming that the energy flux increases from 1.2 w/M2 to about 7.0 w/M2 through positive feedback effects, then wouldn’t these same magical feedbacks have been working when CO2 levels were reduced in the past? Is there evidence in the historical record that this has occurred?
And would the same magical feedback effect have been in action when the energy flux changed in the past for reasons OTHER than changes in CO2 levels? Say an asteroid impact? Tectonic actions? Massive volcanoes?
“……………… my understanding is that a feedback factor greater than one leads to runaway.”
The problem with your question is the word “feedback”. It’s not actually “feedback” as engineers understand it, it’s “amplification”, whether by clouds, water vapor, or whatever nebulous theory one devises for amplification.
Those of us who studied engineering are stuck on the strict engineering interpretation of the word “feedback”. Physicists aren’t so hung up on vocabularic pedantry.
You’ll have to come up with your own theory of how this amplification doesn’t lead to runaway.
e.g…...higher temp air can hold more water vapor, leading to more absorption of outgoing IR radiation and higher temp…..eventually the water vapor condenses out in an entropic system and what seems like a steady state is reached.
This is not to argue that 3C is the correct value. That number was based on the “Charney” report of 43 years ago, which was influenced by an activist from NASA at the time. Several more recent empirical studies put it closer to 2C (e.g. Curry et al)
My point is that you can’t discredit a theory based on its ambiguous terminology.
I thought Le Chatelier applied to chemical equilibria. There is no reason to expect it applies to everything. In particular if there is positive amplification of a change, it won’t apply. It only applies when there is negative feedback. Granted you think the feedback is indeed negative but it is not mainstream. The mainstream position is that feedback is positive.