AI can not make up lies or manipulate you, it can only follow a set of coded instructions. It does not have a personality, it operates only under logic.

Martin Smith “But eventually, no matter how many times the energy is passed around in collisions, it leaves the atmosphere, up or down, as an infrared photon. Yes?”

Zebra: “No. Energy can be transferred from the atmosphere to solid matter by direct contact. (I’m not clear on what you mean by “the” energy.)”

To quote certain wise man: “why is it necessary to add more words, which makes it more likely that you (and others) will get sloppy and confuse things?”

First the nit-picking about word “energy” – when it is obvious for everybody else that it is about the energy in the atmosphere either in the form of IR energy or of collisions

More importantly – your categorical “No” suggests that Martin sentence is WRONG, i.e. that
– either “energy leaving atmosphere” DOES NOT leave via IR at all
-or at the very least – that is not the dominant way to do so, (your alternative – energy transfer to outside via “direct contact” – being as much, or more, important to energy export from atmosphere as IR.

In reality, in the global climate scale – NO net energy is transferred from the atmosphere to either outer space OR to the Earth’s surface:

– 99.9999…. % of energy transferred into space is in the IR form

– worse still the net heating of ground via conduction from air is NEGATIVE – so the rming of the ground by IR would have been HIGHER if it didn’t have TO COUNTER … the cooling of the Earth’s surface by your conduction+convection ( -18.4 W/m2), and latent heat cooling ( -86.4 W/m2).

Not the impression your one gets from your self-confident dressing down of Martin.

But don’t let it stop you from lecturing _others_ that it is _their_ explanations that cause more confusion, and that it is _them_ who “have to work at it”.

Tomáš Kalisz,
If you can make sense of that up-thread Barry E Finch comment you’d be doing better than me. Indeed, your mention of “Trenberth’s diagrams” perhaps throws some light on what is meant by the talk of “tropospheric averages for illustration.” The idea does make sense that “tropospheric averages” for in-out energy must on-average sum to zero (or the troposphere will vapourise in short order). This idea then allows you to sum all the other components of tropospheric warming/cooling to obtain a value for the downwelling component. Except the numbers presented in the up-thread-Barry-E-Finch-comment don’t appear to match the numbers in “Trenberth’s diagrams.” The up-thread-Barry-E-Finch-comment is also ambiguous in that it talks of “the interpretation that has been deliberately used by Deniers for a couple decades to underestimate or deny the effect of an increase?” but without indicating which “interpretation” is considered correct by Barry E Finch.

The “eqiipartition” concept considered by Ray Ladbury is not one I would see assisting understanding here. I would go down the Specific Heat Capacity route. If gases are considered as ideal gases with internal energy restricted to the linear kinetic energy of the gas molecules, the calculated SHC doesn’t match measured SHC. This is because significant energy is also retained as spin and wobble. To heat up a gas, energy is required to add to linear kinetic energy as well as add more spin and wobble, The radiation from Earth’s GHGs is down to the wobble – more temperature, more total wobble energy, which means more wobbles resulting in that emitted radiation.
But also there comes a temperature threshold when more energetic modes of wobble are possible (& also eventually excited electrons) which add new wavelengths of radiation emissions. And, conversely, a temperature dropped below a threshold will reduce the modes of wobble that can be created by a gas. As well as the 15 micron wavelength of our AGW, CO2 absorbs & emits at 4.3 microns and at 2.7 microns but our atmosphere is not warm enough (energetic enough) to form such wobbles (although incoming solar at those wavelengths will be absorbed).
(A comment on my to-do list will reply in-thread somewhere to Ray Ladbury considering the threshold temperatures at which the atmosphere becomes too weak-&-feeble for the 15 micron wobble.)

Martin Smith: “ Then if we add a gigaton of CO2 to the atmosphere, the probability that an infrared photon can escape the atmosphere without being absorbed by a greenhouse gas must decrease ”

Yes, but only to the some extent – some of these IR photons from the Earth service that go straight into space have frequency outside the absorption windows. That’s why greenhouse effect of a given gas is stronger at the lower end of their concentrations – hence

– a ~ 100 ppm increase in co2 between glacial and interglacial had much greater effect than the next 100 ppm increase from preindustrial

– that’s why, in addition to individual molecule ability to absorb IR, CH4, N2o and CFCs have much higher instantaneous GWpotential (GW/molecule or per kg) – their concentrations are simply orders of magnitude lower.

The limited ability to absorb the remaining IR photons therefore limits the sensitivity of climate to CO2. This is however partly offset by what the extra CO2 does to what happens

That was about the IR photons that escape with single absorption into space. The extra Gt of Co2 perhaps more importantly affects those that _are_ absorbed – the more Co2 – the closer to Earth, and reradiated in all directions. The IR re-radiation can
1. be absorbed again and remitted by atmosphere until it:
2. escapes into space
3. is absorbed by Earth surface

On average the “last” (i.e. unabsorbed by air) IR emission to the space is from much higher altitude than the “last” (i.e. unabsorbed by air) IR emission to the Earth. surface.
The higher altitude in troposphere the colder it is. The amount of IR radiated is proportion to the 4th power of abs. temp. The atm temp. drops dramatically with altitude so the difference in IR emitted at the bottom and the top troposphere is massive – see for instance
NASA energy budget, quoting Loeb et al., J. Clim 2009 & Trenberth et al, BAMS 2009:
https://en.wikipedia.org/wiki/Earth%27s_energy_budget#/media/File:The-NASA-Earth's-Energy-Budget-Poster-Radiant-Energy-System-satellite-infrared-radiation-fluxes.jpg

IR energy “emitted by atmosphere” into space: 169.9 /m2 (+ 29.9 /m2 of cloud IR)
vs. IR energy “emitted by atmosphere” into Earth i.e. “back radiation” : 340.3 w/m2

(The atmospheric IR window you talked about is 40.1 /m2)

To sum up – by adding Co2 – in addition to a (slight) closing of that window you talked about
we lower the avg. altitude of the “last” emission toward Earth – making it happen in higher temp. thus increasing the “back radiation”. Plus by absorbing IR closer to Earth and resending its bigger portion toward the Earth, extra reduces the amount of IR available to be sent to space.

So more Co2 -> warmer Earth surface and the air near the ground. This effect is then amplified by the passive positive feedback of the water cycle:
Warmed by CO2 air can accumulate more water vapour before converting it into clouds, which leads to further to warming:
– More water vapour in air -> additional warming.
– Fewer clouds -> less reflection of the solar radiation -> even more additional warming .

I agree on every points.

The IEA scenarios form a framework of 3 technically and economically plausibles scenario
– Currents policies scenario, CPS 2025 : -0.04% / year
– Stated policies scenario, STEPS 2025 : -1.0% / year
– All pledges scenario, APS 2024 : -4.2% / year
That’ enough

TF: “[The medieval warm period] was close to global”

BPL: Not really.

Martin re

https://www.realclimate.org/index.php/archives/2026/06/unforced-variations-june-2026/#comment-849456

Martin, this is what I was responding to:

“But eventually, no matter how many times the energy is passed around in collisions, it leaves the atmosphere, up or down, as an infrared photon. Yes?”

The answer is still no, because it (the energy) can leave the atmosphere “down” by being transferred to land or water by the same “collision” mechanism. No photons involved.

That seems pretty simple to me. What don’t you understand?

Adam Lea
A bit of caution is warranted here. Yes AIs are trained on a vast amount of data, but the dataset is not infinite, nor is it exhaustive. Humans are making the decision what data go into the training set, and they can introduce biases to the output. Facial recognition is famously bad at identifying black faces compared to white faces, mainly because the training database is biased.
XAI is much more likely to draw data from “conservative” sources than progressive sources (and notably in a recent simulation of society, it wiped out the society within 4 days (Google Gemini did slightly better, Open AI lasted a week, and Anthropic’s society thrived).

It is naive to expect that human prejudices will not sneak into AI heuristics when the heuristics are written by humans.

As to the dearth of climate scientists willing to interact with the public, it has been my experience that one tends to sour on the public after they’ve threatened to hang you 7 or 8 times. Even so, there are climate scientist who still interact with the mob, even hostile mobs (Katherine Hayhoe comes to mind). As you might imagine, the rarity of such individuals makes their time valuable and in high demand.

Again, harking back to my experience as an editor at Physics Today, if you can find a researcher who acknowledges his or her own biases and is willing to try and put them aside to present a fair version of their opponents’ views, that can be invaluable. Such people, especially if they are senior in the field present insights that you just aren’t going to get from an AI summary. I don’t think anyone has found a way to make AI weights reflect the value of perspective and experience.

In science, the opinions of such rare individuals tend to play a big role in forming the consensus. They bridge gaps and provide insight in doing so. Heisenberg and Schrödinger debated whether matrix mechanics or wave mechanics represented the “true” expression of the quantum world. Von Neumann and Dirac showed the two viewpoints were equivalent and transformable one to the other. An AI won’t give you that.

Martin Smith: “Google AI estimates that the probability that an infrared photon emitted from the surface escapes the atmosphere to space without ever being absorbed by a greenhouse gas is 10% to 15%.”

You need to be very careful about how you pose such questions. Infrared photons span wavelength ranges from ~780 nm up to 1000 microns. Greenhouse gas absorption takes place over much narrower bandwidths that depend on the gas species, pressure, temperature… A photon n the center of the main CO2 vibrational band (15 microns) has a probability less than 10^-40 of escaping the atmosphere without being absorbed. Even at 14 and 16 microns, the probability is less than 1 in 10^4. At 13 and 17 microns, you start to see probabilities exceeding 10% to first order, although collisional broadening becomes more important for these photons.

And again, the favored de-excitation pathway at low altitudes (below several km) is still collisional, and these relaxation processes do not emit a photon. At STP, the energy of the CO2 vibrational band is well above the average thermal energy of the atmospheric gas molecules–so collisional excitation is a rarer process. As such there is a net flow of energy from the IR band of the GHG to thermal energy of atmospheric gasses.

Also, as to Zebra’s comment, pressure is important for radiative effects–both absorption and emission–so there is a distinction between up and down.