This month’s open thread on climate topics as 2025 wraps up. Please be courteous to each other. Tis the season!
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98 Responses to "Unforced Variations: Dec 2025"
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I call RC readers’ attention to Zeke Hausfather’s blog post last week: https://www.theclimatebrink.com/p/consensus-machines. He offers a brief but helpful tutorial on how generative AIs arrive at their results, But first he says:
Zeke: there is a case to be made that the transition toward using LLMs as sources of knowledge might end up inadvertently recentering scientific expertise and creating a more unified information landscape for society.
If his explanation is accurate, I can see how that might work. But you should argue with him, not me, as my ignorance of the technology is still encyclopedic.
Two categorical aspects to current A.I. — (1) the use of LLMs to pattern match how humans convey (writing, visuals) or process information (software development) and (2) the use of NNs and related tools to train on data as a way to make predictions or solve problems.
The latter can be used in climate science, but it’s not clear what breakthrough it will discover. And if it does discover something, reverse engineering it will still be a pain. Yet, there is still work to be done hammering away via human ingenuity, such as this for modeling fluid dynamics => https://geoenergymath.com/2025/12/02/hidden-latent-manifolds-in-fluid-dynamics/
I also missed he paper in the link below when it first came out, but in it Pierrehumbert describes how and why climate scientists were awarded the Nobel Prize in Physics:
Fluid Mechanics: the quintessential complex system
How things can change in a few years.
Thanks for the Pierrehumbert reference… should be required reading before commenting here.
The ERA5 global SAT anomaly for November averages out at +0.65°C, down on October’s +0.70°C and a sliver below September’s +0.66°C.
The last three months sit above the summer months which averaged +0.47°C.
But November was different from Sept/Oct. The ERA5 numbers at the Uni of Main’s Climate Re-analyser site show November was warmer due to a warm northern hemisphere, (this due to the now-normal warmer NH Autumns that result from AGW. This NH Autumn wobble is usually smaller during La Niñas and the ENSO watchers are showing we have weak La Niña conditions.)
Unlike November, in Sept/Oct the higher SAT anomalies were due to a warmer southern hemisphere and in particular due to unusual Antarctic temperatures which experienced a big warm wobble.
A more reliable (less wobbly) measure of global temperature, the ERA5 60N-60S SST anomaly dropped to an average of +0.29°C for November, this now down below (just) levels projected prior to the “bananas!!” temperatures of 2023/24, the first time since Feb 2023.
(See graphics various at the Banana!! Watch page.)
Tropical “super greenhouse effect” not so super?
Ok, since I can not post a chart here, let me give you the data. Left column are the surface temperatures in the tropics (30°N-30°S) as taken from Ramanathan 2005. In the right column are the average lower troposphere temperatures also within the tropics (30°N-30°S) from the UAH data set.
Ts / Tlt
298.64 272.05
298.82 272.18
299.30 272.31
299.47 272.46
299.36 272.52
298.92 272.42
298.62 272.19
298.57 272.23
298.76 272.27
298.78 272.23
298.56 272.12
298.30 272.08
Max – Min equals 1.17K for Ts and 0.47K for Tlt. The variation of Tlt thus is 60% smaller than that of Ts. Ramanathan argued there was a very strong greenhouse effect in the tropics, and even “super GHE” in the inner tropics. That is because tropical dOLR/dTs is almost zero and partially below zero in the inner tropics. As the surface warms in the annual cycle, there is barely an increase in outgoing longwave radiation, ie the system can not cool itself.
The implicit assumption is that the increase in WV with warming would almost perfectly negate the otherwise to be expected Planck Response. So if you assume a tropical Planck Respone of say 3.5W/m2, while you observe dOLR/dTs ≈ 0, that would indicate the presence of a total of 3.5W/m2 positive feedbacks. Depending on whether you sample for skies only or not, that could also include a cloud feedback component. And most notably, the lapse rate feedback component is assumed to be negative.
WVF + CF + LRF = 3.5
For example you could solve this restriction then like WVF = 4, CF = 0.5, LRF = -1. A strong positive WVF and some neg. LRF. By sampling for clear skies one can try to eliminate the CF variable.
Anyway, the problem is documented in the data above. With Tlt being so sluggish relative to Ts, there is no negative LRF component, but instead it must be a huge positive LRF compoent, like 2.1W/m2, if we assume Tlt as a proxy for Tz. Of course there is no actual positive “lapse rate feedback” in this instance, it is just, let us call it, tropospheric temperature autonomy.
It then follows there is just a small WVF (+CF) residual of only 1.4W/m2. That is a very moderate WVF (+CF), easily to be dominated by a much larger negativ LRF with long term warming. And of course that is no “super GHE”..
I’ve not time to study E. Schaffer comment but anybody who has I suggest you look at what must be about 27 million clear-sky “greenhouse effect (GHE)” measurements for 1998-2014 for 63,000 equal area locations around Earth (grid pixels) at 2:27 at https://www.youtube.com/watch?v=NNgMyDRWWrA This of course is because LWIR-active GHG molecules “absorb” & “manufacture” photons and do not “absorb photons and re-emit 50% back down again”, especially not “to the surface”.
Then there’s fluid dynamics, an entirely-different and vastly-important aspect of Earth’s climate with it’s 2 big fluids “water” and “air”, about which I know bits and bobs but not much. I know they shift energy around Earth at like ~6,000 terawatts and from ocean to land at like ~2,200 terawatts.
Barry E Finch,
Myself, I would hope nobody wastes their time with the E. Schaffer comment above. There’s a lot of strange stuff that doesn’t add up and if you visit the weblink provided by E. Schaffer to find some clarity, you arrive at what he styles “The Greenhouse Defect – Saving the planet …from idiocy – The most disruptive site on climate science.”
An exemplar of the strange stuff in his comment is the insistence that “you observe dOLR/dTs ≈ 0” when, he suggests, the expectation would be something of the order of 3.5Wm^-2/deg C. CERES data shows a healthy annual OLR cycle averaging 3.4Wm^-2 peak-to-peak, not a double-peaked cycle as seen in Tropical SAT but big enough to show dOLR/dTs ≠ 0.
Ramanathan 2005 (book, not article)
http://ruby.fgcu.edu/courses/twimberley/envirophilo/Forcing.pdf
Check page 139 for the “double-peaked cycle” in the tropics.
E. Schaffer,
The difficulty with your reference to “Ramanathan 2005” was because it isn’t a book but a chapter in a book, specifically Kiehl & Ramanathan (2006) ‘Frontiers of Climate Modeling’. However I did find the link provided within your website.
Perhaps I should also point out that I noticed your problematic paywalled reference Raval & Ramanathan (1989) ‘Observational Determination of the Greenhouse Effect’ which is actually available for skinflints and paupers and all, being presented within Manowitz (1990) ‘Gobal Climate Feedbacks’ – Proceedings of the Brookhaven National Laboratory Workshop – June 3rd-6th, 1990.
Your confused presentation does not entice me into trying to understand properly what you are about but I would suggest your seeming mission to find fundamental flaws in the science supporting AGW by identifying some “unthinkable … blunder (that) went unnoticed for decades”: this mission is likely a fools errand.
Concerning specifically the tropical “super GHE” which you seem to want to paint as some figment of errant modelling, a quick look at the CERES data (Clear sky OLR 30N-30S) alongside ERA5 SAT (30N-30S) might just give a measure of your “WVF + LRF” w.r.t. SAT. With that thought in mind, see the graphic here – POSTED 6th December 2025.
MAR, actually the dOLR/dTs < 0 is a reality, as a best-fit trend, from CERES analysis. It's at https://www.youtube.com/watch?v=NNgMyDRWWrA at 2:27 with surface temperature increasing from ~299.5K to ~302.2K the OLR goes down from ~289 w/m**2 to 286 w/m**2, an apparent Super GHE, then rapidly returning, to the linear trend from ~302.2K to ~302.7K. However, it's a best-fit trend from a huge hash of measurements with wide range and seems likely to me that it's to do with some regional variability thing so, sort of, if there's 299.5K in some specific place and 302.2K in some other specific place then for these specific places there's clear-sky OLR of 289 w/m**2 at that specific 299.5K place and of 286 w/m**2 at that specific 302.2K place.
I greatly doubt that the trend through the vast hash plot means that when that 299.5K place warms to 302.2K its OLR goes down. I think its OLR goes up and what's being shown is comparing differing regions with something different between them that causes them not to respond identically. Tropical ocean SST typical is in that range but I don't know the relevance.
One needs to be careful about what perspective is in play. In this video, as far as I have seen it, they exclusive talk about the regional proxy. It is no secret this proxy does not work and is obsolete. Let me quote Dessler et al 2008:
“This is a quantitative estimate of the effect of the changing lapse rate on dOLR/dTs, and it shows that it is negative for almost all values of Ts. In other words, as Ts increases, so does the lapse rate, and the general effect of this is to reduce dOLR/dTs, and therefore OLR, below what they would be if the atmosphere maintained a constant lapse rate.
In most climate-change scenarios, the upper troposphere is expected to warm more than the surface, and the additional radiation from a warmer upper troposphere will act as a negative feedback on the warming.
This result demonstrates the unsuitability of using variations in different regions in our present climate as a proxy for climate change.”
The reason why there is such a reversal of the trend is with the inner tropics. There you have strong convective clouds, optically thick, reaching up to high altitudes and low temperatures. This of course reduces OLR.
Ramanathan however deals with the seasonal proxy and derives the “super GHE” from that perspective.
E. Schaffer says 8 Dec 2025 (with no “Reply” button on my screen, some weird hosting site thing I suppose) “The reason why there is such a reversal of the trend is with the inner tropics. There you have strong convective clouds, optically thick, reaching up to high altitudes and low temperatures. This of course reduces OLR. The CERES plot that I referenced is stated as being measurements for cloud-free skies only.
@BEF My bad, should have looked closer. I still had Fig.1 from Dessler et al 2008 on my mind, which is clear sky data btw.
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2008JD010137
Then thinking about it, it is somewhat odd. Is says “nighttime, clear-sky measurements of OLR” – I mean where are nightime temperatures reaching 310K and more?! Maybe right after sunset, idk. Anyway..
If it is a straight line with nightime temperatures, but features are “bulge” during day time (or all time), that would suggest it is mainly due to the size of the atmospheric window. From previous analyses I tend to believe the clear sky window is about twice (if not more) the size in the outer- and in the inner tropics.
With otherwise identical Ts it might mean a difference of 40-50W/m2 in the share of surface emissions in OLR. OLR itself will then be way more sensitive day time heat in the outer tropics. Would explain why it is straight line for nighttime OLR..
BEF: LWIR-active GHG molecules “absorb” & “manufacture” photons and do not “absorb photons and re-emit 50% back down again”, especially not “to the surface”.
BPL: Not sure what you’re saying here. There is definitely atmospheric back-radiation; we can measure it with instruments.
BPL, he’s trying to be precise about the language.
Photons are converted to energy within the molecule; the energy may be re-emitted or transferred to other molecules through physical interaction. (I believe the latter is the primary mechanism.)
And if the energy is re-emitted downward as a “new photon”, that photon isn’t likely to make it to the surface before being absorbed.
Zebra yep, not at all just a matter of phrasing as bods kept telling me on various Social Media (because everybody assigns their time and interests and they got involved without being interested). There’s an obvious fundamental difference regarding a popular type of Fossil memes, some variants of them, the last couple decades. Isn’t there? As I first posted on RC UV as a Trial Balloon years back to judge interest but was censored, then tried again 6 months later with something obtuse to check the censorship. You & MAR exchanged briefly and MAR noted that I’m crazy, which of course is correct but not relevant to radiative physics, which couldn’t care less about humans.
Barton. I’m not sure why you’re not sure. Looks crystal clear to me and it’s correct in overall essence per orbiting measurement since 1964 IRIS-A on Nimbus 1.
“atmospheric back-radiation; we can measure it with instruments”. Yep the down-welling radiation is measured at land surfaces and I think on Research Vessels. Please indicate how the pyrgeometers identify that these photons entering the sensor were absorbed from below by H2O gas, CO2, CH4, O3, N2O, CFCs molecules (the GHGMs) and then re-emitted back down again as you strongly claim, rather than being photons that were manufactured by the GHGMs as I strongly claim since July 2018 and you strongly refute (Me: when GHGMs collide they sometimes, not often, vibrate, maybe rotate I’ll call it all “oscillate”, as a result and then they sometimes, not often, emit a photon as a result of oscillating. BPL: Nope, they can’t do that, GHGMs are third-rate, defective molecules). On terminology I greatly prefer “down-welling radiation”, because its clear because all understand what “down” means, to “back-radiation” which is meaningless.
Certain molecules and atoms in solids, liquids and gases at certain temperatures are manufacturing photons all the way from the centre of Earth’s core to the top of Earth’s atmosphere. Right? This manufacture doesn’t stop at what we call “the surface”, does it?, it tapers off as gas concentration increases with altitude.
If the ocean somewhere geographically is divided into 27,500,000 layers each 200 microns thick then the H2O molecules in each layer are manufacturing photons and when not manufacturing photons they are either oscillating because they absorbed a photon or doing no manufacturing or absorbing, just “jiggling” with the energy that doesn’t involve photons. Each layer 200 microns thick emits ~460 w/m**2 of photons from its upper and its lower surface when it’s at 27 degrees, ~390 w/m**2 from its upper and its lower surface when it’s at 15 degrees and ~315 w/m**2 of photons from its upper and its lower surface when it’s at 0 degrees. Obviously, the molecules in each layer absorb photons entering from above and below and absorb some portion of their own photons. The ~315 w/m**2 of photons manufactured in the lowest layer 200 microns thick goes from its lower surface into the sea bed and the ~390 w/m**2 of photons (varying ~305 w/m**2 to ~460 w/m**2) manufactured in the highest layer 200 microns thick goes from its upper surface into the atmosphere.
The molecules and atoms from Earth’s core to its surface must be doing the same as the ocean, with the photon fluxes being much vaster.
The N2, O2, Ar molecules don’t manufacture non-negligible amounts but the GHGMs manufacture large photon quantities but not like the solids and liquids quantities because gas density is far lower. Take radiation of 4.5 – 100 microns wavelength except exclude 8.0-9.0 & 10.0-13.0 microns. Suppose the GHGMs in the lowest 200 m of atmosphere absorb all photons going in from above and below. The GHGMs in such a tall layer will also absorb most of the photons they manufacture but there will be leakage from its upper and its lower surface, which are 200 m apart. The leakage from its lower surface is what you (and presumably physicists) are calling “back-radiation” for no meaningful reason because that radiation isn’t going back anywhere. I call it “down-welling radiation” (except when the Gang Du Jour is using “back-radiation” and I don’t want to detract with wordiness from whatever the main point, such as “it’s 0.04%!!” or whatever).
The leakage from its upper surface enters the 200 m of atmosphere above. And so on. Obviously, this is simplified and physicists calculating quantities must determine the photon fluxes up & down from each layer (I know that William & Will Happer used 100 m layers, I don’t know whether that’s typical) and include the portion that can go through the layer. Obviously, the layers would need to get increasingly tall with altitude if one wanted to guarantee that each layer was 100% opaque to photons passing entirely through it, but I’m inferring that physicists don’t do it that way. I’m rather sure that that’s the correct physics as close as matters though and I’m not sure what you’re not sure about with that simple-enough thing. If there are 2 suitably-sized parcels of matter with a common boundary they exchange radiation with the warmer radiating more into the cooler than the cooler radiates into the warmer. Applies to solids, liquids and GHGMs.
On some Social Media places like GoogleysTubes I’d sometimes offer anybody interested to ask me why that isn’t just semantics and then I’d be willing to consume time (for no income) explaining why but I never found interest, just some stupid, ignorant replies such as “@mrunning10 Reported again. Because you’re insane” from the Trolls who are probably the grandsons of the Trolls around here. That’s Life.
Barry E Finch says
On some Social Media places like GoogleysTubes I’d sometimes offer anybody interested to ask me why that isn’t just semantics and then I’d be willing to consume time (for no income) explaining why but I never found interest, just some stupid, ignorant replies such as “@mrunning10 Reported again. Because you’re insane” from the Trolls who are probably the grandsons of the Trolls around here. That’s Life.
Neurodivergent responds; nah couldn’t be you who’s the mad hatter incoherent mad troll. nah, never. It’s everyone else who oppressing’ ya freedumbs dude.
jeez get lost, seriously. or get some therapy.
BEF: On terminology I greatly prefer “down-welling radiation”, because its clear because all understand what “down” means, to “back-radiation” which is meaningless.
BPL: It’s the accepted term. Like “greenhouse effect,” it may not be strictly accurate, but it’s too late to change the usage.
(cont. from https://www.realclimate.org/index.php/archives/2025/11/unforced-variations-nov-2025/#comment-842186 …)
POV = point of view
LOS = line of sight
mass absorption coefficient k_a for the air
= absorption cross-sectional area per unit mass of air [m²/kg]
= Σ_i ( n_i · σ_{a,i} ) ÷ ρ_{air} )
At any given POV, there is some (spectral) radiance ((spectral) brightness) L_ν you see coming from the direction (θ,ϕ); move backward a tiny (infinitesimal/differential) distance ds along the LOS to put additional material in front of you, with optical thickness dτ; because of the tiny amount of this added τ, we can proceed assuming none of its absorption cross sections σ_a overlap. Thus, the fraction of L_ν (seen looking from POV) which is blocked and replaced by the glow B_ ν of that added dτ is that dτ. Ie. The change in L_ν over ds is:
dL_ν = ( B_ ν − L_ν ) · dτ
ie. L_ν + dL_ν = L_ν · ( 1 − dτ ) + B_ ν · dτ
PS: PPIA:
ds = | sec(θ) dz | = | dz / cos(θ) |
dτ = | dτ_{vc} / cos(θ) |
= k_a · ρ_{air} · ds
= Σ_i ( n_i · σ_{a,i} ) · ds
= μ_a · ds = β_a · ds
( see https://en.wikipedia.org/wiki/Schwarzschild%27s_equation_for_radiative_transfer – note they are using “spectral intensity” to refer to spectral radiance. **)
Then integrate over s or τ or z or mp ( |d(mp)|= | ρ_{air} · dz | )…
Exact analytic solutions can be found for some cases eg.
where τ is measured along LOS, in the direction the light is going (you’re looking toward smaller τ in this context), from a point where L_ν = L_{ν,0} & B_ν = B_{ν,0} .
Constant B_ν :
L_ν = B_ν + ( L_{ν,0} − B_{ν,0} ) · exp(−τ)
asymptote: radiance lags behind by 1 unit of τ , ie.
L_{ν,asymp} = B_ν
Linear B_ν = B_{ν,0} + a·τ :
L_ν = B_ν ( τ ) – a + ( L_{ν,0} − B_{ν,0} ) · exp(−τ)
asymptote: radiance lags behind by 1 unit of τ , ie.
L_{ν,asymp} = B_ν ( τ − 1 ) = B_ν ( τ ) – a
More generally, the solution is an asymptote L_{ν,asymp} ( τ ) for a particular function of B_ν ( τ ), plus an exponentially decaying term that is
L_ν − L_{ν,asymp}
at any given τ
(which may be nonzero because that particular function of B_ν ( τ ) may only apply over a limited domain of τ; the decaying perturbation is coming from the L_ν entering that domain).
See https://scienceopinionsfunandotherthings.wordpress.com/2025/12/09/for-asymptotic-radiances-ppia-linear-and-general-cases-wip-awaiting-final-proofread-double-check-diagrams-pending/
(Just posted that; had been sitting on it for awhile; hope to post related posts soon, with formulas of L_ν and flux density Fd_ν for sinusoidal B_ν ( τ ))
** https://www.realclimate.org/index.php/archives/2024/08/unforced-variations-aug-2024/#comment-823976n : (edited from original)
https://en.wikipedia.org/wiki/Radiance#SI_radiometry_units :
Φ (radiant) flux: rate of energy flow, ie. power: [J/s = W]
flux density: flux per unit area (through an area): [W/m²]
I intensity: flux per unit solid angle, in a direction: [W/sr], eg. through an area of some orientation
(note the word “intensity” is often used for other things, though)
L radiance: flux density per unit solid angle, in a direction, through an area facing that direction: [W/(m²·sr)] If you focus at ∞ (infinite distance), then, with some caveats***, radiance corresponds to the brightness you see at a point in your visual field.
spectral ___ ≡ amount of ___ per unit of the spectrum (at a given point in the spectrum).
Eg., over ν: [W/THz] , [W/m²·THz] , … , [W/(m²·sr·THz)] ,
over \tilde{\nu} : [W/(m²·sr·cm‾¹)],
over λ : [W/(m²·sr·µm)]
over E : [W/(m²·sr·eV)]
correction:
Linear B_ν = B_{ν,0} + a·τ :
L_ν = ( B_ν ( τ ) – a ) + [ L_{ν,0} − ( B_{ν,0} − a ) ] · exp(−τ)
= L_{ν,asymp} + [ L_{ν,0} − L_{ν,asymp,0} ] · exp(−τ)
asymptote: radiance lags behind by 1 unit of τ , ie.
L_{ν,asymp} = B_ν ( τ − 1 ) = B_ν ( τ ) – a
complete correction:
Constant B_ν :
L_ν = B_ν + ( L_{ν,0} − B_{ν,0} ) · exp(−τ)
asymptote:
radiance lags behind by 1 unit of τ , ie.L_{ν,asymp} = B_ν
—-
Linear B_ν = B_{ν,0} + a·τ :
L_ν = ( B_ν ( τ ) – a ) + [ L_{ν,0} − ( B_{ν,0} − a ) ] · exp(−τ)
= L_{ν,asymp} + [ L_{ν,0} − L_{ν,asymp,0} ] · exp(−τ)
= L_{ν,asymp} + L_{ν,0}^’ · exp(−τ)
asymptote: radiance lags behind by 1 unit of τ , ie.
L_{ν,asymp} = B_ν ( τ − 1 ) = B_ν ( τ ) – a
(again, see https://scienceopinionsfunandotherthings.wordpress.com/2025/12/09/for-asymptotic-radiances-ppia-linear-and-general-cases-wip-awaiting-final-proofread-double-check-diagrams-pending/ – it’s easier to read there)
Now just multiply by the |cos(θ)| (or cos(θ)) & integrate over solid ange Ω to get spectral flux density Fd_ν (The standard symbol is E_ν or E if not spectral, but that could be confusing…
upward and downward flux densities: Fd↑ , Fd↓
net upward flux density: Fd↑net
net downward flux density: = − Fd↑net )
d [ Fd(↑,↓)_ν ] = L_ν(↑,↓) · |cos(θ)| · dΩ
(you can think of radiance L as the intensity I per unit area facing the direction of L ( ie, (θ,ϕ)); multiplying by the |cosine of θ| gives the intensity per unit horizontal area. PS I’m skipping over some fine points on my L_ν(↑,↓) & θ notation…)
dΩ = sin(θ) dϕ dθ
but for PPIA we can just use dΩ = 2π sin(θ) dθ
and then *(if I remember right)* we get asymptotic values for the linear case:
Fd↑_ν = π (B_ν + ⅔·Γ_{Bτ})
Fd↓_ν = π (B_ν − ⅔· Γ_{Bτ})
Fd↑net = ⁴/₃· Γ_{Bτ}
L_{ν,asymp} = B_ν − Γ_{Bτ} · cos(θ)
where Γ_{Bτ} = ∂(B_ν) / ∂(τ_{vc}) (ie the lapse rate in terms of (based on) the Planck function and vertical optical depth)
(this is how I get the EELs for Fd (“Flotsam and Jetsam” ( https://www.realclimate.org/index.php/archives/2025/06/unforced-variations-jun-2025/#comment-834660 – https://www.realclimate.org/index.php/archives/2025/06/unforced-variations-jun-2025/#comment-834815 )) @ ∆τ = ± ⅔ (which one should be Flotsam and which one should be Jetsam?)
The decay of Fd toward its asymptote is more complex than a simple exp(−∆τ_{vc}), and depends on the directional distribution of L. Interesting case: if you have an inversion layer above a(n isothermal) cloud layer, for some levels of opacity, you can get net radiant heating in the uppermost part of the cloud and net net radiant cooling deeper in the layer, both due to the radiances from above. If the overlying atmosphere is not too opaque, but opaque enough, L↓ from near vertical can be dimmer (colder) than B of the cloud, while L↓ from closer to horizontal can be brighter (hotter) than the cloud’s B. The L closer to vertical penetrates deeper into the cloud; L farther from vertical is absorbed over a shallower layer. Compare to https://scienceopinionsfunandotherthings.wordpress.com/2024/12/10/directionally-averaged-radiance-and-the-semi-gray-skin-temperature-wip-awaiting-final-proofread-double-check-diagrams-pending/ (see last part: *†* …”Meanwhile, the anomalously brighter radiance near vertical penetrates deeper below TOA than the anomalously darker radiance near horizontal “…)
****(please post this in place of last submitted comment)****
complete correction, skipping the ν subscript: τ increasing in the direction the light L is going (you’re looking toward smaller τ in this context), from a point where L = L_0 , B = B_0 .
Constant B :
L = B + ( L_0 − B_0 ) · exp(−τ)
L’_0 = ( L_0 − B_0 )
L_{asymp} = B
—-
Linear B = B(τ) = B_ 0 + a·τ :
L = ( B – a ) + [ L_0 − ( B_0 − a ) ] · exp(−τ)
= L_{asymp} + [ L_0 − L_{asymp,0} ] · exp(−τ)
= L_{asymp} + L’_0 · exp(−τ)
= L_{asymp} + L’
asymptote: radiance lags behind by 1 unit of τ , ie.
L_{asymp} = L_{asymp}(τ) = B(τ−1) = B(τ) – a = B – a
…
d [ Fd(↑,↓) ] = L(↑,↓) · |cos(θ)| · dΩ
… for PPIA we can use dΩ = 2π sin(θ) dθ
“and then *(if I remember right)* we get asymptotic values for the linear case:”
L_{asymp} = B − ΓBτ · cos(θ) for θ = 0° to 180° , (L coming from zenith angle θ)
ie.:
L↑_{asymp} = B + ΓBτ · cos(θ) for θ = 0° to 90° (L going toward zenith angle θ)
L↓_{asymp} = B − ΓBτ · cos(θ) for θ = 0° to 90° (L coming from zenith angle θ)
Fd↑_{asymp} = π ( B + ⅔·ΓBτ )
Fd↓_{asymp} = π (B − ⅔·ΓBτ )
Fd↑net_{asymp} = π · 4/3 · ΓBτ
where ΓBτ = ∂B / ∂(τ_{vc}) (ie the lapse rate in terms of (based on) the Planck function and vertical optical depth)
mp = vertical mass path (measured downward from TOA) [kg/m²], and
k_a = mass absorption coefficient : [m²/kg]
τ_{vc} = vertical optical depth (measured downward from TOA) : [m²/m²]
—-
Generally, you’d want to do a numerical (approximating) integration – over a vertical coordinate (eg. z, p, p/p_{sfc}, mp, τ_{vc}, …
dp = −g · ρ · dz = −g · d(mp)
d(τ_{vc}) = k_a · d(mp) = μ_a · dz
β_a ≡ μ_a = Σ_i ( n_i · σ_{a,i} )
**(isotropic absorption σ_{a,i})**
…),
over solid ange Ω, and over the spectrum.
over a vertical coordinate: an obvious choice is to just directly use dL = ( B − L ) · dτ , ie. approximate the local atmospheric column as a set of thin-enough isothermal layers from i=0 to … (from TOA) (PS index i refers to the layer and to it’s upper boundary (lower boundary of the i−1 layer), ie. TOA is i=0. L↑(TOA) = L↑[i=0]… ; ∆mp[i] = mp[i+1] – mp[i] , …)
But a step up in sophistication would use an approximation of the profile as a set of linear segments, so the decay to a linear asymptote can be used, ie. (PPIA … TBC…) – another step up could use parabolic segments, etc… TBC… You could even use a set of B = linear superposition of sinusoidal terms; the L and Fd values for each term would sum (for each ν – ∆τ[i] for each ∆mp[i] will vary over ν, as will the shape of B(mp) ). But you might want to have values calculated for some vertical resolution, such that there might not be much more to gain from such levels of sophistication…
PS note – if you actually have a B profile with linear segments with sharp features, using the
(spectral) net radiant cooling, per unit mass (of air):
NCm_ν = 4π sr · ( B_ν – L_{ν,4π} ) · k_{a,air}
formula at mp[i] works; but for a good sense of how NCm_ν varies spatially, you’ll want higher vertical resolution getting closer to the sharp turns in ∂B/∂( τ_{vc}) (lapse rate discontinuities) and discontinuities in B(τ_{vc}) (eg. TOA). And/but If you are approximating a smooth curve with a series/set of linear segments, this formula will work ≈ okay (AFAIK) if the ∆τ_{vc}[i] = k_a[i] * ∆mp[i] are small enough, but as they get large, the you’ll get spurious nonzero NCm_ν results, due to the lapse rate discontinuities; the NCm_ν values between the discontinuities will go to 0 as they should, but you’re not calculating those values, and so a graph will only show the erroneous remnant nonzero NCm_ν results. So it’s better to calculate & graph
NCm[i] = ( Fd↑net[i] − Fd↑net[i+1] ) ÷ ∆mp[i]
[W/m² ÷ kg/m² = W/kg]
plotted at mp = mp[i] + ( ∆mp[i] ÷ 2 )
in that case…
discontinuity in B(τ_{vc}): use a ∆τ_{vc}[i] = 0 so that you can calculate two NCm_ν values at same τ_{vc}.
——- —
“parabolic segments”: behold the mighty quadratic asymptote:
B = a·τ² + b·τ + c
L_{asymp} = a·τ² + (b−2·a)·τ + [c−(b−2·a)]
Proof: show ∂L_{asymp}/∂τ = B − L_{asymp}
————– —
integration: over a vertical coordinate, over solid ange Ω, a over the spectrum: I’m guessing that last part may be the hardest. I don’t know how they handle these things in climate models, but I’d guess they use simplifying approximations, eg. – shuffling small bandwidths around by tiny amounts to make the spectra smoother – I read something like that. I imagine parameterizations for some non-PPIA situations (horizontally-patchy, vertically-thick clouds like towering cumulus/cumulonimbus would destroy the PP part)…
Barton, It turns out some other physicist right here on RC UV also has your bemusement or disagreement re “Not sure what you’re saying here. There is definitely atmospheric back-radiation; we can measure it with instruments”. It’s just down below for you to ponder its physics, asserting “On some …. (physics stuff) some therapy” to sharpen and show your science chops. Alternatively BPL you might prefer not to waste a bit of your life.
PO27 (No Reply button) I’ve only time to state I didn’t exactly ignore yours of a couple years back but that doesn’t mean that I’ll ever actually find time to study it, or this bit. Still it’s always there (I mean unless the State deletes it all and increases the chocolate ration from 27 milligrammes to 18 milligrammes).
Barry: “ I mean unless the State deletes it all and increases the chocolate ration from 27 mg to 18 mg.”
I see you are an optimist, Barry. I lived in the State that didn’t see the need to delete it -they would not allow you to post it in the first place. And it increased the chocolate ration, for adults like you, not to 18 mg, but to 0mg/month. So if you really yearned for the taste of chocolate, you would have to trade in your vodka ration for somebody’s kid chocolate ration.
Re Barry E Finch – no problem; I wrote for anyone who might be interested. I’ll just emphasize one point: computational costs/resource constraints aside, (I expect) higher resolution (vertical (optically thinner layers), angular (directional), etc.) is generally better.
(The vertical, horizontal, and temporal distribution of net radiant cooling will affect the climate as it requires/drives/balances/shapes tendencies in convective/advective/latent heating/heat flow etc. Which is why trying to balance CO2+CH4 et al.’s impact on GMST by reducing solar heating (at least without spectral and latitudinal/etc. selectivity) would still result in a changed climate (& also the O3, photosynthesis, stomata, pH effects) https://www.realclimate.org/index.php/archives/2025/11/unforced-variations-nov-2025/#comment-84254 1re https://www.realclimate.org/index.php/archives/2025/11/unforced-variations-nov-2025/#comment-842488 )
PS I try not to take it for granted that I am able to often enjoy ~ 300 – 1000 times that amount of chocolate daily.
UAH TLT has been posted for November with a global anomaly of +0.43°C, down on Sept & Oct (+0.53°C) and pretty-much back down to the anomalies of the summer. (JJA averaged +0.41°C.)
This drop from October was all southern hemisphere (down to +0.27°C from +0.55°C) with the NH showing an increase (up to +0.59°C from +0.52°C.)
The TLT anomalies have been carving a different path from the SAT through the “bananas!!” period.
Smoothed-out, the global TLT anomalies peaked in March 2024 and have been dropping pretty consistently ever since. The NH ‘plateaued’ rather than peaked and began to drop quite strongly from September 2024 while the SH peaked in March 2024 dropping until Jan 2025 since when it has remained essentially flat. (See this graphed out in the yellow graphics at the foot of the The Banana!!! Watch page
Surface sends net radiation, sensible & water evaporation-condensing into troposphere. When it’s warmer it sends more of those and I just calculated the increase in water evaporation-condensing equals 0.7 degrees of warmer air if it really has been 9% more H2O gas for the +1.3 degrees and if the energy was used for thermal capacity, warming air, instead of being latent. I’ve no time to ponder whether or not that means anything about the TLT change vs surface temperature change (the surface is solid or liquid but the measurement is made nominally 2m above the surface so perhaps I’ve noted nothing of interest).
Been a long time since I commented here. Thanks for the continued efforts you all put in. I can’t find the answer to a question that occurred to me lately and I’d be very grateful if someone could point me in the right direction:
If Hansen is right and climate sensitivity is higher than IPCC puts it, leading to the acceleration he posits, does that mean that reductions in atmospheric GHGs would reduce temperature faster than current modelling?
Thanks in advance if anyone cares to help me out.
Good question. It depends on how complicated an answer you want.
A few comments back, Paul P posted this reference, which I found very useful:
https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/fluid-mechanics-the-quintessential-complex-system/313B5D56A3BF8D4776D398A638A23C72
So one could answer you by saying “you gotta do the math”.
But I think you have to be clear about your question. Do you mean reducing CO2 after it is already added, or reducing the future value by reducing emissions now?
For example, if you have already melted all the ice on the planet and then you figure out a magic way to draw down CO2, you would have to create completely new models.
“Do you mean reducing CO2 after it is already added, or reducing the future value by reducing emissions now?”
Thanks for responding. I mean “reducing CO2 after it is already added”, although obviously the latter scenario would be preferable..
in Re to One Anonymous Bloke, 6 Dec 2025 at 11:36 AM,
https://www.realclimate.org/index.php/archives/2025/12/unforced-variations-dec-2025/#comment-842675
Dear Sir,
Thank you for your clarification that you ask how the climate will change after the “net zero” emissions are reached.
In this respect, MA Rodger cited on 23 Aug 2025 at 12:00 PM,
https://www.realclimate.org/index.php/archives/2025/08/unforced-variations-aug-2025/comment-page-2/#comment-838092 ,
two references, namely
MacDougall et al (2020) ‘Is there warming in the pipeline? A multi-model analysis of the Zero Emissions Commitment from CO2’
https://bg.copernicus.org/articles/17/2987/2020/
and
Borowiak et al (2024) ‘Projected Global Temperature Changes After Net Zero Are Small But Significant’
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024GL108654 .
In the following discussion, he explained that these publications bring evidence that while global mean surface temperature (GMST) rise will likely stop a few decades after the “net zero” in emissions of non-condensing greenhouse gases (GHG) is reached, the Earth energy imbalance (EEI) will stay positive and the sea level rise (SLR) will continue for millennia.
A closer look suggests that there is a spread across climate models tested – some may show a longer continuing temperature rise after the “net zero”, some an almost instant temperature decline.
It is likely a result of different rates of two counteracting processes that decide about the outcome in each individual model – the natural CO2 drawdown from the atmosphere (that decides about the decline of Earth energy imbalance (EEI)) on one hand, and proportionality of the GMST change to the EEI (which may be, in my understanding, closely related to the climate sensitivity) on the other hand.
If so, I think that it may be well possible that if the “hot” models indeed apply for the present Earth climate, the “zero emission commitment” (ZEC) can be higher than that should be expected in case that the climate sensitivity is moderate.
As a layman, I will, however, definitely appreciate a comment (and, possibly, a correction) from someone more skilled in the art of climate science.
Best regards
Tomáš
Thanks for that reply Tomáš.
My question is more about any removal of CO2 (in the event that a mechanism could be invented to do this) than ‘net zero’, and the difference (if any) between what the IPCC might predict vs. Hansen’s higher climate sensitivity.
Does a higher climate sensitivity imply that changes resulting from a (purely theoretical) reduction in CO2 would happen faster?
I just found this link from 2008, wherein Hansen et al mention “a possibility of seeding irreversible catastrophic effects.” So perhaps the answer to my question is “probably not”.
https://arxiv.org/abs/0804.1126
One Anonymous Bloke, you really should ask jim himself. Too easy to be misled otherwise.
https://jimehansen.substack.com/
or email https://www.columbia.edu/~jeh1/mailings/
Do subscribe: Hansen is the ‘featured’ top item (2nd link}
https://csas.earth.columbia.edu/
Global Warming Has Accelerated: Are the United Nations and the Public Well-Informed? – https://www.tandfonline.com/doi/full/10.1080/00139157.2025.2434494
I see these categories under “Our Work”
-Climate Research
-Climate Data
-Public Awareness & Policy Solutions
–Our Children’s Trust
–Citizen’s Climate Lobby
–350.org
Thanks very much for that, Neurodivergent, I’ve subscribed to JH’s substack.
OAB,
Yes. And it doesn’t really have to be a “catastrophic” change like my example of all the ice melting; it’s a matter of the system becoming “different enough” from what we are working with now.
That’s the real question with the whole “acceleration” discussion. The temperature (GMST) is one of many characteristic of the system that respond to the increase in total system energy caused by CO2.
But the current models may not be able to predict a future GMST if, for example, the AMOC slows down to some arbitrary level. That’s the nature of complex systems as discussed in the reference I gave. They are complex; you have to do the math.
Thanks Zebra. “The temperature (GMST) is one of many characteristic of the system”
An insight I hadn’t considered let alone appreciated.
I’ll point out 1 quick thing for now which is “Pattern Effect”. If it’s real then it’s unstoppable because it’s a Done Deal. Assessed at =0.8 degrees over a few hundred years it requires no Forcing because it’s only that the ocean redistributes heat already in it and asserted it’ll reduce low cloud cover (over eastern tropical Pacific I think I recall but check that yourself). At https://www.youtube.com/watch?v=jlolDdnSHCE
Re: One Anonymous Bloke
In a vague, i.e. inconsequential sense – probably yes, but the real question whether it will be significant/comparable to the Hansen acceleration.
Your question seems to anticipate symmetry – but there is no reason to expect one – Hansen’s higher sensitivity requires strong positive feedbacks and/or crossing tippings points. And different feedback have different mechanism and thus different strengths and inertias. For example, you can start reducing CO2 conc., but the ice would be still melting with lower albedo countering the cooling expected from dropping CO2.
And to see why we should not expect symmetry – see the glacial-interglacial sequences:
they are triggered by the orbital cycles, but they cause negligible differences in the avg. solar radiation Earth’s receives (its all about heating in Arctic in summer, even if it’s globally balanced by cooling elsewhere or winter), so the massive difference in GMST between Ice max and T max – is almost exclusively thanks to the four positive feedbacks: ice albedo-T, water cycle-T, CO2-T and CH4-T, each different in strengths, geographic patterns, inertia etc.) and likely different responses on the way up as on the way down. Not surprisingly deglaciation phase is MANY times shorter than the glaciation phase.
So if even a symmetrical signal (orbital cycles) is not a guarantee of a symmetrical outcome (glacial-interglacial sequences), then what expect when even the signal (here: atm. Co2 changes) is not likely to be symmetrical?
So the only way to evaluate is to run the models. With the “current-modelling” from what I heard on RC (M.Mann?) – the net-zero human emissions CO2 – by allowing natural sinks to REDUCE atm. CO2 –
could ~ STABILIZE GMST. So obviously no symmetry there.
And the “IPCC” models are not as dependent on the positive feedbacks as is Hansen – so asymmetry in Hansen would likely be more pronounced.
And that’s not even talking about tipping points, which importance is tied SOLELY to their asymmetry
(if they were symmetrical, thus easily reversible – they wouldn’t be tipping points).
So the answer to your question is either trivial (“probably yes”), or non-answer (“we don’t know whether it will be significant or not”).
Given that, a more interesting question is – why do you ask? ;-)
Thanks for that detailed response Piotr. Your remarks about asymmetry are especially helpful. As to why I asked the question, it’s partly curiosity and partly to avoid a mistaken sense of optimism.
This is an interesting review of what’s wrong with AI ‘science” and how publication and peer review are being corrupted: Artificial intelligence research has a slop problem, academics say: ‘It’s a mess’. AI research in question as author claims to have written over 100 papers on AI that one expert calls a ‘disaster’ – https://www.theguardian.com/technology/2025/dec/06/ai-research-papers [I’m going to try to use blockquote for the following but if it doesn’t work, please know that the following is all quote:}
similar cases among AI researchers, who said their newly popular discipline faces a deluge of low-quality research papers, fueled by academic pressures and, in some cases, AI tools.
…. “team endeavors” run by his company, Algoverse. The company charges $3,325 to high-school students and undergraduates for a selective 12-week online mentoring experience – which involves help submitting work to conferences.
….
Meanwhile, students and academics are facing mounting pressure to rack up publications and keep up with their peers. It is uncommon to produce a double-digit number – much less triple – of high quality academic computer science papers in a year, academics said. Farid says that at times, his students have “vibe coded” papers to up their publication counts. | “So many young people want to get into AI. There’s a frenzy right now,” …. “It’s just a mess. You can’t keep up, you can’t publish, you can’t do good work, you can’t be thoughtful,” he said.
…. “You have no chance, no chance as an average reader to try to understand what is going on in the scientific literature. Your signal-to-noise ratio is basically one. I can barely go to these conferences and figure out what the hell is going on.” | “What I tell students is that, if what you’re trying to optimize publishing papers, you know, it’s actually honestly not that hard to do. Just do really crappy low-quality work and bomb conferences with it. But if you want to do really thoughtful, careful work, you’re at a disadvantage because you’re effectively unilaterally disarmed,” he said.
I think many researchers are sensitive to this situation. The year 2020 marked early usage of LLM and by 2o21 there was more widespread adoption. My own research findings, which I assune can be misconstrued as LLM-assisted, all happened prior to 2019 and I haven’t published anything since. Not that I did this intentionally, but as time goes by, I’d like to maintain the focus on the original published work to avoid the appearance of it being tainted by LLM vibe content.
Perhaps there will be a demarcation of B.C. – “Before ChatGPT”, and A.D. – “Anno Discursio” to indicate when a work was formulated or published.
Oops: after saying I’d try blockquote I failed to do so. It’s still all quote, fwiw. A valuable article on the problem with publishing and peer review today. The lies have it!
Just Have a Think (Dave Borlace) is turning the heat up a notch (as the actual heat continues to increase):
New analysis. How corporate overlords are unlawfully ignoring future climate impacts. – https://www.youtube.com/watch?v=YtS0j4hXCAs
“Fiduciary Duty is a phrase often touted by corporate CEOs and Wall Street types to justify their dodgy deals and questionable board level decisions. But Fiduciary Duty also involves safeguarding the LONG-TERM security of shareholders investments. Now a group of expert lawyers has published a report outlining how Exec Boards and Fund Managers are acting unlawfully if they do not fully factor in the impacts of the climate emergency. And the findings are quite challenging.”
Susan, good stuff, thanks. Unfortunately, with Pres. Trump’s plans for the next SEC head and his upcoming pick for Federal Reserve head to replace Powell next year beginning to leak, it looks pretty clear that climate change and corporate governance policies are going bye-bye until the Democratic Party can retake the White House.
C.C. Side Topic — A bright sign I think I can see is with the U.S. Supreme’s having repeatedly expanded the reach of the Executive Branch, there is going to be an opportunity for the D’s to do some real things, that if done right, could create positive changes (including on AGW) for the swathes of America being stepped on now in Gilded Age II.
I watched the following YouTube yesterday that (conveniently) does a reasonable job of outlining my philosophy on the subject. It’s an conversation with Marc Dunkelman hosted by John Avalon (39min). If you Susan, or anyone, does have time to watch it one of these days, weeks or months ahead, I’d love to hear it:
“America’s New Crisis: We Can’t Build (w/ Marc Dunkelman) | How to Fix It”
https://m.youtube.com/watch?v=drL2yh8fiQg&pp=0gcJCR4Bo7VqN5tD
David, why would climate change and corporate governance policies go bye-bye when we have many Democrat-run states?
Interesting video. They point out over and over that the reason Dems never get anything done on environmental or other “progressive” projects is too much government red tape, over-regulation, threat of lawsuits, excessive permit requirements, and all the things that Dems love and that Republicans have said for decades need to be reduced. They even say that Reagan’s ideas would benefit us – get government out of the way. They said that every time an environmental or progressive project comes up, out come the “progressive” NIMBYs to stop it.
After pointing out for a half hour all of the Democrat policies that prevent environmental and/or “progressive” projects to be built, they trot out their possible DEMOCRAT presidential candidates! So, they think the same group causing total dysfunction in government is going to somehow, magically, all of the sudden become competent and start successfully building things. Hilarious.
Then they insult Trump (the guy with bad hair in the WH) – the man who, more than any other in government, has a proven track record of successfully building large projects, and in the past 10 months working tirelessly to Make America Great Again.. He’s famous for fixing in 4 months what Democrats in NYC government couldn’t fix in many years:
https://www.forbes.com/sites/offwhitepapers/2015/08/24/donald-trump-and-the-wollman-rinking-of-american-politics/
Then, to top it all off, at 36:48, the 2 Democrats say they want to Make America Great Again. BWAHAHAHA!
Every day in the newspapers of blue holes across the nation, are articles about how the Democrats running the blue holes are going to fix public schools so the kids can read and write, make housing affordable, fix the homeless problem, fix traffic congestion, reduce crime, and on and on. Every year, in the same newspapers it is reported how all of the above and more are WORSE than the year before and they print the promises of the Democrat mayor, governor and city council members to make the problems better in the new year. It never happens – it just gets worse. -year after year for DECADES. Every election, all the voters in the blue holes STAMP THE DONKEY, and wonder why their blue hole continues to decline. You know the old saying about doing the same thing over and over and expecting different results……
The place is a joke. Neither side of US politics offers anything tangible rational or sane. Trump is a 21st century Mussolini fascist – and idiot in power with bullying thugs lording it over the rest
James Carvill throws his imprimatur into the ring. Comment by Peter Turchin
More recently, his tone has changed. In the latest essay, Out With Woke. In With Rage (Nov. 24, 2025), he has started to formulate a positive program for the Democrats:
JC (by nature?)
” I am now an 81-year-old man and I know that in the minds of many, I carry the torch from a so-called centrist political era. Yet it is abundantly clear even to me that the Democratic Party must now run on the most populist economic platform since the Great Depression.”
This is a big shift and it reflects the revolutionary times we live in. As I wrote in End Times, the Democratic Party did a great job suppressing its populist wing. This contributed to the defeat of its presidential candidates in both 2016 and 2024. What Carville calls “centrist,” actually, means “conducting policies for and by the ruling class.” Now that it has been overthrown, the
Democratic Party is ripe for the takeover by the left-wing populists (just like the Republican Part may be in the process of being taken over by the right-wing populists). And that’s what Carville essentially proposes.
Carville’s piece reads a lot like my posts in the series A Chronicle of Revolution. I doubt he read it; most likely, it’s starting to dawn on the former ruling party that “centrism” is dead. A few quotes:
“The people are revolting, and they have been for some time.”
“the rigged, screwed-up, morally bankrupt system”
“If you’re a student of history, the French Revolution is in the American wind.”
“Le peuple se lève.”
https://peterturchin.substack.com/p/the-return-of-the-left-populism
circling the drain with Peter Turchin
https://www.youtube.com/watch?v=d2VTHcUeCA0
Harvard tracks the youth voice
the mainstream media and political parties are viewed more as threats than assets.
many indicators pointing to widespread financial, emotional, and social strain.
expecting fewer opportunities, greater threats to job security, and diminished meaning in their careers.
Social trust is unraveling, as many young Americans avoid political conversations, fear judgment for sharing their views, and doubt that people with opposing perspectives want what’s best for the country.
reveals a generation under profound strain, as young Americans report deep economic insecurity, eroding trust in democratic institutions, and growing social fragmentation.
https://iop.harvard.edu/youth-poll/51st-edition-fall-2025
Pathological Self-Interest and Greed Rules America – a republic in name only
Mr. Know it All, I’m curious–do you actually believe what you wrote in this comment?
KIA: the reason Dems never get anything done on environmental or other “progressive” projects is too much government red tape, over-regulation, threat of lawsuits, excessive permit requirements, and all the things that Dems love and that Republicans have said for decades need to be reduced.
BPL: We got a lot done. We no longer have pollution emergencies like Donora, PA in 1948. Rivers no longer catch on fire. We got lead out of gasoline. My home town of Pittsburgh no longer has a coating of soot all over the buildings and cars each morning. So your starting point is counterfactual.
In Re to Barton Paul Levenson, 14 Dec 2025 at 9:21 AM,
https://www.realclimate.org/index.php/archives/2025/12/unforced-variations-dec-2025/#comment-842861
Hallo Barton,
KIA may be partly right. I think that it might have been David who pointed to the following report
https://energyimplementation.github.io/implementation-report.pdf
summarizing “lessons to learn” from the difference between goals and achievments of the Biden’s administration.
Greetings
Tomáš
Copernicus has posted ERA5 SAT for November confirming the Nov anomaly at +0.65°C. This continues the marked increase in anomaly through Sept-Nov averaging +0.67°C. The unusually warm SH seen in both Sept & Oct (driven by particularly unusual Antractic anomalies) faded through Nov with the NH showing some of its normal Autumn upward wobble. (By way of comparison. through the Summer, Jun-Aug globally averaged +0.47°C.)
With that Sep-Nov upward wobble, the 2025 Jan-Nov average is now effectively identical to the 2023 Jan-Dec annual average. Which year has the edge depends on which anomaly base you choose. (Using 1850-1900, 2023=+1.481°C, 2025-to-date=+1.477°C, using 1991-2020, 2023=+0.6008°C, 2025-to-date=+0.6013°C.) So a December average of more than +0.60°C would put 2025 as the 2nd warmest year on record. The first seven days of December are showing an average of +0.54°C. But it’s early days.
Contrary to what you were intimating in late 2024 and early mid 2025, is this a quite understated acknowledgment that your expectations were completely wrong?
I hope so.
Also I can safely conclude now that it’s is also an additional acknowledgement that you’re seeing Jim Hansen as being correct in his expectations what would support (or not support) his general theory culminating in his last 3 published papers ….. about the 2023-2024 massive spike in global temperatures.
quoting
The Acid Test: Global Temperature in 2025
James Hansen and Pushker Kharecha 20 February 2025
The unprecedented leap of global temperature in 2023 and early 2024 exceeded 0.4°C (Fig. 1). We
and coauthors2 interpret that uniquely large warming as being due about equally to a moderate El
Nino and reduction of ship aerosols, with a smaller contribution from the present solar maximum
(our entire paper, including Abstract & Supplementary Material is available in a single compressed
PDF here). An “acid” test of our interpretation will be provided by the 2025 global temperature:
unlike the 1997-98 and 2015-16 El Ninos, which were followed by global cooling of more than
0.3°C and 0.2°C, respectively, we expect global temperature in 2025 to remain near or above the
1.5°C level. Indeed, the 2025 might even set a new record despite the present weak La Nina. There
are two independent reasons. First, the “new” climate forcing due to reduction of sulfate aerosols
over the ocean remains in place, and, second, high climate sensitivity (~4.5°C for doubled CO2)
implies that the warming from recently added forcings is still growing significantly.
https://www.columbia.edu/~jeh1/mailings/2025/Acid.Test.20Feb2025.pdf
And this one here too
2025 Global Temperature
James Hansen and Pushker Kharecha 15 April 2025
Abstract.
Global temperature for 2025 should decline little, if at all, from the record 2024 level.
Absence of a large temperature decline after the huge El Nino-spurred temperature increase in
2023-24 will provide further confirmation that IPCC’s best estimates for climate sensitivity and
aerosol climate forcing were both underestimates. Specifically, 2025 global temperature should
remain near or above +1.5C relative to 1880-1920, and, if the tropics remain ENSO-neutral,
there is good chance that 2025 may even exceed the 2024 record high global temperature
https://www.columbia.edu/~jeh1/mailings/2025/2025GlobalTemperature.15April2025.pdf
Hansen get’s it right yet again.
No wonder then his science papers are being referenced all over the place today, such as in the The 2025 state of the climate report: a planet on the brink
https://michaelmann.net/wp-content/uploads/2025/10/RippleEtAlBioscience2025.pdf
Barry E Finch, Piotr and Atomsk’s Sanakan must be feeling gutted and embarrassed about their anti-Hansen anti-peer reviewed science trolling all over again.
Neurodivergent (or whoever you are),
I don’t know what it is you think was “intimating in late 2024 and early mid 2025,” but I am not aware of any volte-face in my understanding of the cause of the 2023-24 “bananas!!” temperatures.
Hansen acolytes such as yourself should consider the dropping temperature anomalies through 2025 and see that they do not suggest the “bananas!!” resulted from positive forcings resulting from the 2020 marine pollution regs. And I was always of the opinion that such forcings could not be made to fit the evidential basis of the “bananas!!”
Hansen did hedge his bets in a paper this year insisting the “bananas!!” (or perhaps it was the post-2010 acceleration generally) could be due to reducing aerosols but could also be due to the appearance of cloud feedbacks. He argued that both would have the same implications for ECS. Feedbacks can disappear when the initiating forcing or temperature wobble is remove so cloud feedbacks remain on the table. But the aerosol forcing idea is dead.
As for Hansen’s “acid test”, my reading has always been that when Hansen & Kharecha said “we expect global temperature in 2025 to remain near or above the 1.5°C level.” this concerned monthly anomalies. If it did not, their follow-on statement “Indeed, the 2025 might even set a new record despite the present weak La Nina” doesn’t make a lot of sense.
2025 monthly temperatures didn’t remain near to +1.5ºC (dropping to +1.25ºC for July) and the 2025 annual anomaly has never looked like threatening to best 2024’s +1.6ºC.
All we have is 2023 with a “bananas!!” end to the year and 2025 with a “bananas!!” beginning vying for the 2nd place. Likely they will be =2nd.
Re: “Barry E Finch, Piotr and Atomsk’s Sanakan must be feeling gutted and embarrassed about their anti-Hansen anti-peer reviewed science trolling all over again.“
That’s nice, Mo Yunus, a.k.a. several other sockpuppet accounts. You’ve implicitly confirmed I was right about you. Regardless of how many sockpuppet accounts you use, you revert to your usual tactics, like idolizing Dr. James Hansen to the point that you angrily misrepresent even mild criticism of what he says.
Let me know when you can cogently address the actual criticisms of what Hansen said. I won’t hold my breath, though, since that would require you replacing your idol worship with the integrity and intellect needed to grasp topics like statistical tests for acceleration, selection bias, etc. You’ve never managed that across your several accounts.
Re: “[“]An “acid” test of our interpretation will be provided by the 2025 global temperature: unlike the 1997-98 and 2015-16 El Ninos, which were followed by global cooling of more than 0.3°C and 0.2°C, respectively, we expect global temperature in 2025 to remain near or above the 1.5°C level. Indeed, the 2025 might even set a new record despite the present weak La Nina.[“] […] Hansen get’s it right yet again. […] Barry E Finch, Piotr and Atomsk’s Sanakan must be feeling gutted and embarrassed about their anti-Hansen anti-peer reviewed science trolling all over again.“
The temperature drop from 2024 to 2025 is at least as large as the global surface temperature drop from 2016 to 2017. Similarly, the difference between the 2023/2024 average vs. 2025 is at least as negative as the difference between the 2015/2016 average vs. 2017. So no, 2025 did not set another record, nor is its temperature drop from 2023/2024 so small as to make 2023/2024 appear starkly “unlike the 1997-98 and 2015-16 El Ninos.”
Moreover, my criticisms of Hansen’s claims have not been about the global temperature anomaly for 2025 vs. for 2023/2024. My criticisms are instead about him using statistically unsound methods to claim acceleration of global surface warming, when statistically sound methods instead do not show statistically significant warming. I also previously noted that Barry E Finch gave a warming trend comparable to what your fellow Hansen idolizer Geoff Miell cited from Hansen:
You quoting Hansen on 2025 vs. 2023/2024 does not rebut Barry E Finch’s point on the multi-decadal warming trend, nor does it rebut my point on statistically significant acceleration. Like so many of Hansen’s fans, you don’t get the difference between shorter-term fluctuations vs. longer-term trends that are more statistically robust. And/or this great illustration of how you willfully misrepresent criticism of Hansen’s claims.
So 5 questions for you, Neurodivergent:
The answers to these questions are:
I predict you will not honestly address those questions, much like Geoff Miell repeatedly avoided pertinent questions:
Atomsk: “ Barry E Finch gave a warming trend comparable to what your fellow Hansen idolizer Geoff Miell cited from Hansen
I am not sure they actually “idolize Hansen” – they USE Hansen for their overriding psychological need – to prop up their ego by association with Hansen intellectual and ethical authority:
if I, [Multitroll, Geoff Miell, etc …), without much climate science background, can see (in Hansen) what top climate scientists can’t or refuse to see, then I must be very, very, smart and virtuous .
So they use Hansen as a drunkard would use a police-grade heavy flashlight – not for enlightenment, but to bash opponents head.
With supporters like that, who needs enemies?
Yeah, Piotr. It’s rather sad. It’s the same petty behavior Neurodivergent showed when posting under their Lleim sockpuppet account:
It’s gotten to the point that they don’t even see the implications of what Hansen is saying, as I illustrated with my 4th question. And as I said elsewhere, I think a lot of this is driven by misinformation from people like Leon Simons.
Re: “My criticisms are instead about him using statistically unsound methods to claim acceleration of global surface warming, when statistically sound methods instead do not show statistically significant warming.”
I mistakenly left out a word. That should instead read:
‘My criticisms are instead about him using statistically unsound methods to claim acceleration of global surface warming, when statistically sound methods instead do not show statistically significant warming acceleration.’
Re: “And/or this great illustration of how you willfully misrepresent criticism of Hansen’s claims.”
I mistakenly left out two words. That should instead read:
‘And/or this is a great illustration of how you willfully misrepresent criticism of Hansen’s claims.’
No honest attempt to address the questions, as expected. Just more evidence-free ranting and evasion, likely largely AI-generated.
https://www.realclimate.org/index.php/archives/2025/12/unforced-variations-dec-2025/#comment-842875
Atomsk’s Sanakan,
To be fair, I think the answer to your question 1) is “No, not yet.”
Hansen’s ‘Acid test’ only makes sense if it refers to something other than annual temperatures.. The quote “the 1997-98 and 2015-16 El Ninos, which were followed by global cooling of more than 0.3°C and 0.2°C” likely refers to the rolling 12=month values plotted-out by the blue trace in the graphic at the top of the Hansen & Kharecha posting linked above. The numbers used look like GISTEMP so the rolling 12-month peak and troughs (with end of period dates) would be:-
1998 … 8 .. +0.65°C
2000 … 2 .. +0.36°C
Cooling … 0.30°C
2016 … 9 .. +1.07°C
2018 … 4 .. +0.85°C
Cooling … 0.22°C
2024 … 8 .. +1.32°C
2025 … 11 .. +1.21°C (latest)
Cooling … 0.11°C so far
The problem with Hansen’s ‘Acid test’ is that it wasn’t explained very sharply. The general idea that the 2023/24 El Niño was not the entire driving force behind the “bananas!!” is likely true. However, Hansen’s ‘Acid test’ was going a step further by saying 2025 would see no cooling relative to 2024 (and could even see further warming), this predicated on the view that the extra ingredient was a forcing which would continue its work after the 2023/24 El Niño had come and gone. That ‘forcing’ explanation appears to be wrong.
They all understate here but such is the nature of scientific blogs and they are harsh too on others.
Pete Best,
“They all understate here”
If you wish to claim people understate the climate problem, you have to provide some specific evidence they are doing this. For example MAR and AS are both obviously warmists, but have posted lengthy comments sceptical of some of the more extreme claims made on the climate issue.
Where exactly do you think they are getting it wrong? Please understand just quoting someone who thinks climate change will be at the extreme end or whatever, is not adequate. You have to show in detail where MARs and AS’s specific claims and reasoning are wrong.
Personally, I think climate change could potentially be towards the upper level of estimates but I’ve seen some really extreme claims that simply lack credibility. Not an expert myself but some of this stuff is still just obviously very speculative and isn’t thought through.
Pete Best’s comments are just the usual substance-free tone trolling. One way to deal with that sort of person is to ask them pertinent questions, give them sufficient information to answer the questions, and then see whether they address the questions. Trolls expose themselves by not honestly and cogently engaging with the questions. Typically they just bravely run away.
I’ve asked the questions in this comment above. So I’ll leave it to the trolls to expose themselves, as the geologist and science journalist Peter Hadfield (a.k.a. Potholer54) noted:
https://michaelmann.net/wp-content/uploads/2025/10/RippleEtAlBioscience2025.pdf
This paper seems to be stating it’s getting a bit desperate but you wouldn’t know it trying to read the posts here .
It’s a scientific blog and I get that and I know the world appears to be presently warming between 0.2C and 0.3C presently. James Hansen is a sincere scientist so I see no reason for the IPCC to try and get his work. From being published
‘If you wish to claim people understate the climate problem, you have to provide some specific evidence they are doing this. ….
Where exactly do you think they are getting it wrong? ‘
The usual bit–trying to model AND predict the next El Nino. “Getting it wrong” is perhaps not the right wording, as the skill level has yet to produce anything useful. Researchers are still trying though, with many papers featuring machine learning approaches.
I don’t recall why I’d be “gutted” but I might have lost track. May 2023 I questioned the EEI 1.33 w/m**2 because I’d gotten “Karina von Schuckmann et al’s latest 0.78 w/m**2 (I eye balled 0.88 w/m**2 for last 4 years off her plot with her recent talk), so I looked into it and found of course that was correct that EEI had increased a lot (I recall 0.90 w/m**2 over 20 years) so I updated my notes and started pondering with the new information and I posted:
“OK, I didn’t realize that the EEI has been increasing at a rate as high as the 0.5 w/m**2 / decade. I’ll have to take another look at my quick calculation 5 years ago of 0.20 degrees / decade + 0.06 degrees / decade**2 for +GMST if I ever find the time (it was based of course on what I’d read as the prior increase in EEI since 1970)” so if I was “gutted” it would have been in May 2023 and some people just aren’t keeping up to date because it’s December 2025 now. I wasn’t “gutted” in May 2023, I just updated my notes. It’s interesting.
“Neurodivergent”: “Barry E Finch, Piotr and Atomsk’s Sanakan must be feeling gutted and embarrassed about their anti-Hansen anti-peer reviewed science trolling all over again.”
What can be asserted without evidence can also be dismissed without evidence,
So stop giving the neurodivergents bad name, the same way you have tarred the reputation of a renewable expert Pedro Prieto by appropriating his name and pushing your claims as him.
The search engines and AI won’t know that you have been an imposter and will forever associate his name with your troll production. Way to pay a “tribute” to him, as you defended your practice.
As for “feeling gutted and embarrassed” – isn’t this what you feel looking in the mirror in the morning? If I were you – incapable of understanding what you read and on what you base your derision toward others, and seeing your opponents constantly running circles around you – I would have felt “gutted and embarrassed” too.
Hansen’s words do not mean what you think they mean, nor do posts of Barry, Atomsk or me.
And no, you can’t hide your intellectual and ethical shallowness by draping yourself in Jim Hansen (the “ authority by association“).
Nor will we pull our punches just because you now appropriated a “ neurodivergent ” label – nobody, save perhaps Susan ;-), will go:
“ Atomsk, for God’s sake – stop battering that neurodivergent boy with falsifiable arguments and with your “Yes or No” questions – see you’d made that poor boy cry ”
Now, go away or we shall taunt you a second time. Fetchez la vache!
Piotr: “As for “feeling gutted and embarrassed” – isn’t this what you feel looking in the mirror in the morning? If I were you – incapable of understanding what you read and on what you base your derision toward others, and seeing your opponents constantly running circles around you – I would have felt “gutted and embarrassed” too.”
This guy probably doesn’t feel gutted and embarrassed. He / she obviously has some sort of superiority complex. Some sort of narcissistic psychological issue. He/ she probably genuinely believes they are right. Neuro divergent may in this instance mean genuinely neurodivergent. You and I would be gutted and embarrassed (and would tidy up our act) but dont assume everyone would be. But he / she does indeed misinterpret what people say.
Nigel “This guy probably doesn’t feel “gutted and embarrassed“.
not at a conscious level
Nigel: “ He / she obviously has some sort of superiority complex.”
that masks the deep seated inferiority: ” A superiority complex is an inflated self-image masking deep-seated inferiority, leading to arrogance, dominance, and devaluing others”
Nigel “Neuro divergent may in this instance mean genuinely neurodivergent. ”
Should an internet troll be considered “neurodivergent”, or just a pathetic type, who hasn’t achieved anything meaningful in life – so he tries to bait opponents, because this would give him the sense of control – thus make his life not pathetic (would a pathetic person be able to “own” supposedly smart people ?). Does it make the multi-troll -neurodivergent ?
Don’t think so. Being a pathetic human being is not something he can’t do anything about, as would be the case for a real neurodivergent.
So the Occam’s razor suggests multitroll adopted this handle to be cute – look, if I call myself “neurodivergent” then it must be ironic – thus proving that I am anything but
Since photons in the infrared wavelengths are being tossed about (or manufactured or re-emitted or down-welling or back-radiated) I’m NOT going to participate in that, but throw in mechanical work being done by the temperature difference between surface and space. The invention will not fix the world but might evolve into producing useful work in specific situations. But one component could be much more useful.
“Scientists Generate Power At Night By Passively Beaming Heat into Outer Space. It’s “Like Solar Cells in Reverse”
UC Davis engineers have invented a Stirling engine that captures Earth’s escaping heat to generate power from the night sky.”
The secret sauce is the coating that the device exposes to the open sky.
“The top plate (warm side) uses a paint that is highly emissive in the infrared. This allows heat to pass directly through a clear section of the atmosphere, called the atmospheric transparency window (between 8 and 13 µm). The heat radiates directly into space, cooling the panel far below the ambient air temperature.
“It doesn’t actually have to touch space physically, it can just interact radiatively with space,” Munday explains.”
That from here, and the article links to the underlying Science Advances research article.
https://www.zmescience.com/future/scientists-generate-power-at-night-by-passively-beaming-heat-into-outer-space-its-like-solar-cells-in-reverse/
But there are now a number of different ways researchers have invented to create coatings (or materials) that radiate their heat in that transparency bandwidth range. Science had a paper maybe ten years ago about a plastic film with embedded glass nanoparticles that radiate in the range. That can be manufactured by the mile on standard plastic sheet machinery. Others have worked on paints and other coatings that do the same.
Another team found a way to treat wood such that the resulting product doesn’t just radiate to space, but it’s stronger, too.
https://www.science.org/content/article/engineered-wood-radiates-heat-space-potentially-slashing-cooling-costs.
And another one from just last month: “Researchers at the University of Sydney and start-up Dewpoint Innovations have developed a nanoengineered polymer paint-like coating that can passively cool buildings and capture water directly from the air — all without energy input.”
https://www.techbriefs.com/component/content/article/54267-this-paint-can-cool-buildings-without-energy-input
These won’t fix “the world” either, but since IR was a topic, it’s worth thinking about buildings and other structures in hot, sunny, arid places where there’s little water vapor at night to block those IR photons and their trip to space, taking away fairly substantial heat from what’s under the treated surface. Could be a lot of use for that. Zero power cooling.
For whatever reason, the first time I’d read of the plastic film I mentioned above, my first thought of a practical use was shaded shelter for livestock in places where subsistence farming along with goats or cattle happens in hot areas.
More specifically a case would be around the Arabian Sea where they’re first predicting brief episodes where wet-bulb temperatures lethal to large mammals without cooling. If some type of cattle shed with a passively-cooling roof was inexpensive enough, and durable, it could mean the difference between a living farmer without any surviving livestock or a farmer continuing to survive without becoming another refugee. Some kind of earthen walls and maybe a more transmissive mass on the roof so cooling at night would persist a bit in the day – guessing on it, but that could make a difference.
Here’s that first piece I’d seen – 2017.
https://www.science.org/content/article/cheap-plastic-film-cools-whatever-it-touches-10-c
I think something would have to be done to prevent the film or paint from working during the day.
The difficulty with passive cooling under extreme wet bulb conditions is that they occur with an extremely high dew point. This means that nearly all of the cooling power would go into condensing water instead of cooling the air. If the condensed water was collected, it could be useful in a desert climate, however.
John, didn’t you just describe a dehumidifier?
Zebra, that’s not what I understood b fagan to be describing. He seems to be talking about passive cooling for an animal shelter by coating the top. That’s not my idea of a dehumidifier.
Sorry, John, I was trying to be too clever (but making a serious point).
My understanding of the problem with high wet bulb temps is that the body can’t cool itself through evaporation.
Conventional dehumidifiers produce thermal energy themselves, of course, but this technique would avoid that problem, so even if it didn’t remove thermal energy (or just a little), it should still be beneficial for the occupants. (?)
Hi Steven and John,
I did some poking around and there’s a lot of stuff looking at how to -actually- use the transparency window rather than just my thought of gluing the film onto sheets of corrugated iron. Unsurprising since cooling becomes increasingly important and avoiding extra energy demand and local heat retention are both bonus points. So here are a few links and they seem to also have some interesting other links to more work.
PS on the condensed water, John, that’s part of what they describe in the research written about in the NASA Techbriefs link (last in my initial post). Other research on using passive cooling, including at least one of the ones below, also looks to avoid the problem of condensation – the good news is this is a lot of engineering and construction-trade level work so again, this won’t Fix The World, but it seems likely it will help specific use cases and needs.
This one has passive heating AND cooling. Published: 12 September 2024 in Nature Communications
Passive isothermal film with self-switchable radiative cooling-driven water sorption layer for arid climate applications
https://www.nature.com/articles/s41467-024-52328-z
This one for passive cooling even in high temperatures and significant (up to 100%) humidity. Published 2019 in Optics Express
Nighttime radiative cooling in hot and humid climates
They calculate results but also did some experimental testing of a simple physical mock-up where they got this: “We experimentally demonstrated nighttime radiative cooling in summer with RH from 53–100%. Even at a hot summer night at T-ambient = 29 °C with RH = 100%, we achieved radiative cooling of 5.2 °C below ambient. With a more sophisticated photonic design, a similar, if not better, cooling performance could be achieved in hot and humid climates at daytime.”
https://opg.optica.org/oe/fulltext.cfm?uri=oe-27-22-31587
And this one – 2022 in International Journal of Thermofluids
Potential of hybrid radiant cooling with infrared-transparent membranes to improve thermal comfort in hot and humid climate
https://www.sciencedirect.com/science/article/pii/S2666202722000775
Emph mine:
I’m glad they’re upfront about the low power densities; the value seems to be for (in present-day developed-nation context) niche applications.
Apologies for breaking Susan’s Law, but I have to push back on this claim:
On part 1: depends on the surface which would otherwise be there. Maybe if It’s a low-emmisivity surface like dry rock? (depends on spectrum of albedo) … OLR would be maintained if a perfect emitter at just the right temperature Tc replaces a surface with Th and lower emmisivity ε (in the window*) with
window ∫ ε · B_h· dν = window ∫B_c· dν
i = c,h
E_{Ti} = k·T_i
B_i = (2h·ν³/c²) ÷ ( exp(−hν/E_{Ti}) – 1 )
( https://en.wikipedia.org/wiki/Planck%27s_law )
But actually the ε may need to be lower to make up for the technology’s ε=0 of the outside the window* (*ε=1 of the technology) because the atmosphere’s window has transitional bandwidth.
On part 2: No. It increases the fraction by taking that heat flow out of the atm. window and sending it to do useful work, which is then dissipated ultimately as heat, which now must still find a way out of the Earth System.
Back to part 1- as it is with the atmospheric heat engine ( https://www.realclimate.org/index.php/archives/2025/07/unforced-variations-july-2025/#comment-835660
https://www.realclimate.org/index.php/archives/2025/07/unforced-variations-july-2025/#comment-835665
), solar power – thermal (max conversion efficiency at Th → T_Sun, but max net energy flux into collector at cold Th ), PV (open circuit V vs short circuit I, … more…), and wind turbines (complete conversion of flow through swept area requires that flow = 0 (complete deflection by pressure); Betz limit),
having a nonzero conversion efficiency requires Tc get cooler, which reduces the OLR; equilibrating to the brightness T of the window maximizes the conversion efficiency, but then there is no flux to convert. (The window OLR / heat flow into Th = Tc/Th ideally. Eg. 6 W/m² supply could come from 300 K Th, 270 K Tc (1-Tc/Th = 90%), 60 W/m² inflow, 54 W/m² emitted.) (Ideally, the window of ε=1 would cover the bandwidth over which the emitted W/(m²·cm¯¹) would be greater than the sfc Fd↓ (Tc still warmer then brightness temperature of ↓flux density @ sfc), with ε=0 outside of that (includes SW bandwidth, so would work in sunlight).
… But probably not a big issue given the likely niche application.
Fd = flux density
correction:
having a nonzero conversion efficiency requires Tc get cooler, which reduces the OLR; equilibrating to the brightness T of the window’s Fd↓@sfc maximizes the conversion efficiency, but then there is no flux to convert. (The window ( emitted Fd↑ − Fd↓@sfc) / (heat flow into Th) = Tc/Th ideally. Eg. 6 W/m² supply could come from 300 K Th, 270 K Tc (1-Tc/Th = 90%), 60 W/m² inflow, 54 W/m² = emitted Fd↑ − Fd↓@sfc) . (Ideally, the window of ε=1 would cover the bandwidth over which the emitted W/(m²·cm¯¹) would be greater than the sfc Fd↓_ν (Tc still warmer then brightness temperature of ↓flux density @ sfc), with ε=0 outside of that (includes SW bandwidth, so would work in sunlight – wait, that might make up for the OLR dimming ).
“It was almost a pre-bunking effort,” — Daniel Swain, climate scientist with University of California Agriculture and Natural Resources
Not paywalled…
“EPA erases references to human-caused climate change from websites
The agency revamped its webpages to feature natural causes of rising temperatures such as the Earth’s orbit.”
By JEAN CHEMNICK | 12/09/2025 06:18 AM EST
E&E News by Politico
https://www.eenews.net/articles/epa-erases-references-to-human-caused-climate-change-from-websites/
Off Topic: Lee Zeldin is drawing slowly increasing calls for Pres.Trump to fire him by some conservative groups aligned with MAHA movement over EPA’s sweeping efforts to relax, ignore, postpone, remove rules for regulating a number of toxic chemicals. Maybe a sliver of hope? A Christmas wish perhaps for a man who has overseen such extraordinary damage in so many ways in ten months? (lol, no comments needed, just a momentary spark of fool’s hope by me)
UN environment report ‘hijacked’ by US and others over fossil fuels, top scientist says – https://www.bbc.com/news/articles/c1w9ge93w9po
begin quote ->
“I thought we had gone beyond the point of recognizing that when you burn oil, this big, thick black stuff comes up, and it probably isn’t good, especially when you try and breathe it in,” said Dr David Broadstock, with the Lantau Group, and one of the report’s lead authors.
“It’s kind of pretty obvious, and yet we’re still seeing parties wanting to pursue the increasing scale of production of such things,” he told BBC News.
Since taking office President Trump has sought to boost fossil fuel production and roll back US commitments to fight climate change, calling for the country to be a global energy superpower with cheap and reliable resources.
He has also sought to get the US courts to overturn the idea that carbon dioxide is a danger to public health. His government has also followed up with efforts to restrict or limit the efforts of international bodies that set out to tackle warming.
This year has seen efforts at international plastics negotiations, at the international maritime organisation and during COP30 to strike out language that states that climate change is a major issue requiring the world to move away rapidly from fossil fuels.
The disagreement over the Global Environment Outlook report will raise concerns about future negotiations for the Intergovernmental Panel on Climate Change reports as these studies are seen as the bedrock of global efforts to limit global warming. <-end quote
https://youtu.be/4-a-qeMyaPE?si=ooH2TWSDn8jn5mMK
Hansen makes some good points I think.
An example of expert herd mentality
is the response to our global warming
acceleration paper. The next day,
these experts unanimously condemned
our paper in the media.
[and on blogs including RC]
Not one of them discussed the physics in
our paper or explained what was wrong.
Instead, there were ad homonym remarks.
“Hansen makes lots of mistakes. Hansen
exaggerates. Hansen is not collegial.”
For many years over a decade now, James Hansen has been asserting in public, repeatedly :
‘What we witness now is scientific reticence on steroids’
Ignore him. Maybe the truth will go away.
…says the sockpuppet account still bravely running away from questions that shows it’s wrong.
https://www.realclimate.org/index.php/archives/2025/12/unforced-variations-dec-2025/#comment-842796
“And then I say I trust the crowd because I haven’t got any views of my own.”
~Penrose
https://www.youtube.com/watch?v=7HE7xgiFXRE
Q:What is it that you disagree with your colleagues about?
If I disagreed strongly with my colleagues about it,
then I probably shouldn’t be thinking it,
because of the wisdom of the crowds;
they believe that they’re the ones that are most likely incorrect if everyone else believes something different [sic]
Q: But how is it that you can maintain this level of, maybe belief is not the correct word, conviction, credence in your own ideas, despite being criticized by colleagues? How do you psychologically deal with that?
It’s just that the arguments are wrong. I mean, I don’t see any good arguments against my point of view.
The thing about the cosmology is that it’s a crazy idea. My idea is a crazy idea,
and I admit it’s a crazy idea. But you need something crazy because the conventional ideas
don’t work.
And I think people just sort of go with the crowd.
I’m just not persuaded by going with the crowd. It doesn’t seem to me… I mean,
There are lots of things I don’t know anything about.
And then I say I trust the crowd because I haven’t got any views of my own.
Reply to JCM
The “fallacy of popular opinions” is the Ad Populum fallacy (Appeal to Popularity/Bandwagon Effect), which incorrectly claims something is true, good, or right just because many people believe it, ignoring evidence or logic. It exploits our desire to fit in (bandwagon effect) and uses emotions or majority agreement as proof, even though history shows the majority can be wrong (like the Earth being the center of the universe). This fallacy is common in advertising, politics, and everyday debates, relying on conformity rather than facts.
How it works:
Argument Structure: “Everyone/Most people believe X, therefore X is true”.
Leverages Emotion: Plays on the human tendency to conform or belong (the “bandwagon effect”).
Avoids Evidence: Substitutes popularity for solid reasoning or factual proof.
In climate science debates, a related error occurs when consensus or model agreement is treated as equivalent to established fact. Many key quantities — such as cloud feedbacks, aerosol forcing, ocean circulation, and regional climate responses — are not directly observed but estimated through models with evolving assumptions. When provisional outputs are presented as settled facts, and model agreement is mistaken for empirical confirmation across the full climate system rather than a limited metric like global mean temperature, this becomes a form of reified consensus rather than evidence-based reasoning.
What’s happening is not just appeal to popularity. It’s a stacked set of epistemic errors that get collapsed into “we have the facts” when, in reality, we have provisional, model-dependent estimates.
The Fallacy of Reified Consensus (also called “Consensus Reification” in philosophy of science)
Definition:
Treating a scientific consensus — especially one derived from models, assumptions, and parameterisations — as if it were a settled body of empirical fact, rather than a provisional framework subject to revision.
In short: Turning agreement into evidence. Calling this out is not anti-science — it’s pro-scientific humility. The disarming in climate dialogues is manifold in sidestepping the “facts”.
We have Argument from Authority (Ad Verecundiam) – “The IPCC says…” – “97% of scientists agree…”
This is used improperly when:
uncertainty ranges are downplayed
dissenting evidence is dismissed without engagement
authority substitutes for falsifiable validation
Accusations of trolling thrown about and allegations that sockpuppets have no facts arguments or scientific support. It does not get more anti-science anti-reason and fallacious than that low step. The bastion of scoundrels and deeply engrained institutional censorship wins the skirmish and lose the war against humanity and truth. The anonymous nobody accusers are the Concern Trolls here.
Model Platonism (Informal but accurate) A category error where:
climate models are treated as the climate itself
internal consistency is mistaken for empirical completeness
This is especially relevant for:
cloud feedbacks
aerosol forcing
ocean heat uptake
regional circulation
Models are tools, not observations. The opposite is deployed by trolls to disarm confuse and manipulate people.
The Fallacy of Precision
Presents narrow confidence intervals, average means, precise numerical targets (1.5°C, 2.0°C),
exact timelines when the underlying system is in fact chaotic, poorly constrained, and dependent on assumptions that change over time
Complexity and Precision does not equate to Accuracy. In Reasoning or Math. Incompetent anonymous Concern Trolls tells you it does. The authoritive experts look on and say nothing.
Surrogate Validation Fallacy is an important one. Definition:
Claiming a model is “validated” because it reproduces one aggregate metric (e.g. global mean temperature), while failing across many coupled components (clouds, ice, precipitation, circulation, regional variability).
Matching one curve only does not mean the work, “the experiment” is understanding the system correctly. When everything else fails real world observations then the one that appears to match is also wrong.
The Trolls and silent expert observers can’t cope with facts evidence nor reason and logic. It just doesn’t compute within their distorted world view anymore. They have become what they rail against.
N: a related error occurs when consensus or model agreement is treated as equivalent to established fact.
BPL: I’m pretty sure you don’t know what “scientific consensus” means.
Neurodivergent @14 Dec 2025 at 9:09 PM
His / her comments are an entire forest of strawman arguments, and non sequiturs and evidence free accusations against nameless people and muddled, confused thinking, and inflammatory claims (ie:trolling). Which is somewhat ironic.
Just more evidence-free ranting and tone trolling that’s likely largely AI-generated. All to bravely run away from evidence and questions that debunk a trolling sockpuppet account.
https://www.realclimate.org/index.php/archives/2025/12/unforced-variations-dec-2025/#comment-842796
https://www.realclimate.org/index.php/archives/2025/11/raising-climate-literacy/#comment-842607
If crowds were wise we wouldn’t have Trump treating the US as his personal protection racket, and climate denial would not exist. We wouldn’t have ready access to high powered killing machines. We wouldn’t blame victims. We wouldn’t have extreme income inequality. We wouldn’t enable toxic waste to give gazillionaires more att our expense. etc. etc. etc.
Both GISTEMP and NOAA have posted for November.
GISTEMP gives November with an anomaly of +1.22°C, a little up on October’s +1.19°C.
The NH saw a big rise (+1.47°C to +1.69°C) which is to be expected as northern summers are taking longer to cool off under AGW, while the SH saw a not-quite-so-big drop (+0.91°C to +0.76°C).
2025-to-date (+1.20°C) is running cooler than Jan-Nov 2024 (+1.29°C) but warmer than Jan-Nov 2023 (+1.17°C). This makes a 2nd place 2025 a certainty in GISTEMP, requiring Dec25 to average +91°C or less to drop 2025 down to 3rd warmest. The last time a GISTEMP anomaly that low was seen was Jan 2023.
Meanwhile NOAA gives November with an anomaly of +1.18°C, a little down on October’s +1.19°C, the NH rise (+1.65°C up from +1.52°C) being a bit smaller than the SH drop (+0.71°C down from +0.87°C).
The difference in the Jan-Nov average anomalies for 2025 & 2023 is smaller in the NOAA numbers making a 2nd place for 2025 pretty unlikely, requiring a Dec anomaly above +1.31°C.
Please note, global and hemispheric temperature anomalies are with respect to the 1901-2000 average.
Do not confuse this data with the Paris set +1.5C anomaly and current tracked GMST
https://yaleclimateconnections.org/2025/12/3rd-warmest-on-record-again-november-2025-keeps-a-hot-global-streak-going/
What exactly are you posting about – is it significant posting the exact temperatures from satellites etc
This article states that the past 3 years are the warmest on record and 2023 and 2025 will tie for second warmest.
Are you suggesting the warming is significant ?
Copernicus
The global three-year average temperature for 2023–2025 will likely exceed 1.5°C above pre-industrial levels for the first time.
November 2025 was the third-warmest November on record globally, keeping 2025 on track to be the second- or third-warmest year recorded.
NOAA’s NCEI November 2025 was Earth’s third-warmest November in analyses of global weather data going back to 1850, …………………… NOT 1900-2000 RANGE THAT RODGER USES
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According to NOAA, the year-to-date period (January-November) has been the 2nd-warmest on record for the globe, running just 0.01°C (0.02°F) above the January-November value for 2023 and 0.1°C (0.2°F) behind the value for 2024.
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James Hansen and Pushker Kharecha 15 April 2025
Abstract. Global temperature for 2025 should decline little, if at all, from the record 2024 level
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Absence of a large temperature decline after the huge El Nino-spurred temperature increase in
2023-24 will provide further confirmation that IPCC’s best estimates for climate sensitivity and
aerosol climate forcing were both underestimates.
Specifically, 2025 global temperature should remain near or above +1.5C relative to 1880-1920
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>WHICH IT HAS
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https://www.columbia.edu/~jeh1/mailings/2025/2025GlobalTemperature.15April2025.pdf
A delightful ditty about physics, climate, scientists and weather [found via Gavin Schmidt’s Bluesky]
Call Me Charney: A GFD Parody
https://www.youtube.com/watch?v=qbMwX2uo23U