Posted On: Saturday - March 11th 2023 5:51PM MST
In Topics:   Global Climate Stupidity  Science
(Continued from Part 1)
Here again is the video of German Astrophysicist Dr. Sabine Hossenfelder on the actual process of the "greenhouse effect":
First, I gotta say this: Mrs. Hossenfelder, please, please, consider letting your upper and lower teeth come apart while you're talking! Her English is fine. Her accent is not bad at all. It's just, well, if she would leave a gap for the words to come out... they could come out to me, and I'd have an easier time listening. (It's not THAT bad, but you've got to concentrate more than you should have to.)
This video lecture is all about radiation heat transfer and almost solely about that to/from layers of gas in the atmosphere. Scientists study radiation heat transfer usually to from/to surfaces and to/from fluids (normally gases), and engineers do the same. For the latter, if they actually WORK with it, the results have to be right. That means, ALL processes and effects must be accounted for if any types of models are to match reality. Radiation is one of 3 modes of heat transfer, the others being conduction and convection. There's a lot to ALL of the modes, but we'll get to it regarding radiation shortly here.
Put simply, the idea of the greenhouse effect and Carbon Dioxide is that energy of certain wavelengths transferred from the Earth's surface (again keeping it simple) to deep space are absorbed by the CO2 up there. Those wavelengths blocked are not so much of the spectrum of the incoming solar radiative heat transfer, so the result is more energy staying within the control volume of the Earth and its atmosphere than with less CO2 up there. The equilibrium average temperature of the whole deal gets slightly higher, IF, and that's a big one, all else doesn't change.
What I just wrote is something of a misunderstanding of it all, Dr. Hossenfelder maintains. Besides explaining more about the radiation emission frequency spectrum of the 3 "greenhouse gases", water, CO2, and "meethane"** and the absorption of infrared by CO2 especially - nothing that negates the last paragraph (the "high school" explanation) - the importance of the altitude of that layer of CO2 is what she says has been misunderstood.
Let me use a few paragraphs now to summarize radiation heat transfer. Like all heat transfer, the rate goes up from 0 with objects (in the case of radiation, surfaces or masses of gas) at the same temperature and increases with temperature difference. Unlike in conduction and convection***, rather than the heat transfer rate being a linear function of ΔT (Temperature difference), along with other factors, of course, radiation heat transfer is odd on that score. It comes out in the math that the rate is a function of the difference of T's to the 4th power. Note: That's NOT (Th - Tc)4. It's Th4 - Tc4. If you're wondering about the units, the temperatures must be in degrees Kelvin (K) or, for the English units system, degrees Rankine**** (R) - these are both referenced to absolute zero, i.e. no molecular movement.
Peak Stupidity is about the last place you'll get engineering derivations (almost every single one is based on Newtons's laws and/or the 1st law of Thermodynamics, BTW). Here, though, at least, is the very basic radiation heat transfer equation, from a surface to another surface or to/from the oft-used non-body called the sky: qnet = 𝜎ɛAS(𝑇h4 - Tc4), where
qnet is the net heat transfer rate (units could be Watts) between surfaces.
𝜎 is the Stefan-Boltzman constant, equal to 5.67 x 10 -8 W/m2K4
ɛ is the emissivity of the surface, from 0 for a "white" surface (poor emitter and poor absorber) to approaching 1.0 for that theoretical "Black!" body (a good absorber and a good emitter).
A is the surface area.
S is not in your standard science equation, but this "Shape Factor" is necessary for real-life problems.
Th and Tc are the absolute temperatures of the hotter and colder surfaces (or gases) respectively. A positive rate of heat transfer is always the case from the hotter body to the colder one.
"What's all that got to do with the price of tea in China", you ask? Well, it'll go way up if the seas boils, I'm here to tell you! No, this is likely fairly straight forward to the reader, but let me give you a cool real-world example of one part of this, the Shape Factors that come into play in real life ENGINEERING problems. (I am not completely sure if Dr. Hossenfelder gets this with respect to the layers of gases in the atmosphere, but we'll get to that.)
Take my old muscle car,
I pick the dew because that's when I noticed, a few times, that the window on one side had dew but the one on the other didn't. This rules out natural convection as the cause, because its effect would be symmetric. What was going on? There's a row of bushes on one side, close to the car. Let me digress from this digression to the Shape Factors. Engineers use the term "see"***** a lot, as in, the car roof sees the night sky about 50%, it sees the house walls for 30% and the bushes 20%, like that, the "S" for one radiative heat transfer path being 0.50 for the sky, 0.30 for the house, etc.. It's more complicated than that even, because unless you have a plane surface with the other components (surfaces or the sky) far enough away, one point on the surface "sees" more of this other surface than another part of that hotter surface does******. Some engineers may divide this up in a common-sense fashion, but for the really fastidious, Calculus, Bitchez!
The side next to the bushes was radiating mostly to them, at a much higher temperature than the night sky. No dew was present. The other side was more in the clear, so it got colder than the other, and it had dew on it... mostly. The really cool part was the portion of window near the side mirror on the dew side. I brought up that this is an old muscle car to explain that it has the old close-in small mirrors. Well, there was a dew-free zone on the window the exact shape of the mirror. How convenient for driving! What will nature think of next? Well, go figure, this portion of the glass was in a sky shadow (yes, cue up Cat pre-Moslem Stevens), radiating to the mirror and mirror housing. Those had an absolute temperature much higher than the night sky, probably near the same T as the window. Oh man, then there's the reflection of IR from the mirror ...
Before I forget, let me add: There are surfaces, and then there is the deep sky. For layers of the atmosphere radiating outward, deep space is taken, if I recall correctly, taken to be at an average of 4 K (way down near absolute zero) for calculations.
The point of all this is to explain to the reader not just that this stuff can get complicated fast, but even in the atmosphere with those nice hollow-spherical layers, everything radiates to or gets radiation from, EVERYTHING ELSE. Dr. Hossenfelder, even in her "PhD version" 2nd half of the video either doesn't really get that, or has explained it poorly. I do lean toward the latter, but she had a chance to explain this when she told her viewers toward the end (16:30) that she had been misled by the arrow directions in the previous "greenhouse effect" schematics she'd seen in textbooks.
OK, now, finally, let me get to the video in a more direct fashion. Much I attribute to poor explaining and some to possible non-understanding. Early on (03:25) and near the middle (10:38), she describes infrared emissions as "light". She's not technically wrong, but if you're going to make this clear, you should be certain to call all of it radiation. Visible light too is part of the electromagnetic spectrum. She knows this, but the non-difference between "light" and "radiation" would confuse the "high school" version viewer. Along with this, near the end of the video, Dr. Hoffenfelder said (about the incoming radiation to Earth's surface at 16:38) "It's converted to infrared radiation...", a really confusing way of putting it. Nothing is being "converted". The ground absorbs energy at some wavelengths and emits at some others. (At least she got the light/radiation bit right by this point.) She said this correctly earlier on (4:40) though.
I get that this science popularizer is not an atmospheric scientist. That does not excuse her, seeing as the video is almost all about the atmosphere, from not knowing what the Tropopause is. In the first half of the video as she tells us, in the "High School version" that the atmospheric temperature decrease with altitude (07:10), she notes (09:30) "If you go further up, it remains constant for a bit..." A bit?! It's 8 to 10 km thick right there in the diagram. In the diagrams her Stratosphere includes the Tropopause. Is that just her wanting to save time? That notwithstanding, what I think is a true lack of understanding on the part of this Astrophysicist is the explanation of the increase in temperature with altitude in the thick (not materially, but geometrically) layer of the atmosphere called the Stratosphere. Much of the 2nd half of the video concerns the Stratosphere.
The idea gas law doesn't explain it, as pressure continually decreases with altitude. Why does the temperature go up with altitude in this layer? "That's because the atmosphere up there absorbs some of the incoming sunlight." (09:40 and 14:45) (Make that "solar radiation", please!) OK, but then during the rest of the presentation, there is this natural assumption that when CO2, or other greenhouse gases exist at higher levels they are at a lower temperature. "... at higher altitudes, where the temperature is lower". At 12:48 she says "if the concentration of Carbon Dioxide increase further, then the emission of more and more wavelengths of the spectrum moves up to higher altitudes, so they move to lower temperatures." I get that the temperatures anywhere in the Stratosphere are lower than the bottom ~5 km of the Troposphere (the entire Troposphere******* is our realm, and where the weather occurs). However, why is this additional CO2 MUCH higher up? If it's just higher WITHIN the Stratosphere, it'd be warmer at higher altitudes. Earlier, at 09:55, we are told: "Pushing the effective altitude of emission up reduces the temperature of emissions, and that brings the system out of balance." (More on those last 3 words to come.)
This is utterly confusing to me. Either there's something more to the explanation, or she's contradicting the established fact she herself mentioned that T's go up with altitude in the Stratosphere. It's the Stratospheric cooling that's her gotcha in this entire presentation as to why she is right and they, those "Climate Change Deniers", are wrong. Yes, this is the point in question at which the agenda of Sabine Hossenfelder comes out in the open. Here's the line:
"If you've ever had the pleasure of interacting with a climate change denier, this is Exhibit A."She's a 1967 paper that she says shows that more CO2 increases Stratospheric cooling, which she says has been observed, and she maintains that this shows us that the warming of the Tropopause, questionable as that is, and the cooling up higher, demonstrate that the questionable warming is NOT a function of an increase in solar radiation influx. OK, but, her satellite data upper Stratospheric cooling graph displayed at 16:00 show (with the eruption interruption of Mt. Pinatubo in the Philippines in1991) a 1.5 C decrease from 1980 through 1996, a level period from then till about 2002, a 0.5 C decrease from then through 2009, then level or a slight increase since. That's not so very conclusive.
(12:17, or start at ~12:05 for more context)
In addition to less radiative heat transfer to deep space, wouldn't a cooler layer up high also result in increased transfer TO said layer from material and surfaces below? Of course
Finally, let me get to one more type of wording out of Dr. Hossenfelder that I believe is a combination of poor explanation AND an agenda in the wording. That would be that "out of balance" business that I mentioned, which appears a few times. Whatever you think of it, the Climate Calamity™ theory is a long-term process. Atmospheric composition changes, so absorption and emission of electromagnetic radiation changes, but there's no such thing as anything being "out of balance" involved. Things don't just jump. As concentration gets gradually higher, absorption gets higher (just a vague example), T goes up, so radiation in a certain direction gets higher. A new Equilibrium is established, but the physics don't and can't allow for anything to be out of some kind of balance. That terminology would make one wonder whether this lady understands the idea of changing the equilibrium. She does, I'm sure, but then I think she uses this phrasing as a scare tactic. How about, as she does admit at one point, something like "the temperature at the lower levels will increase this small amount"? The Earth is still balanced! Don't be alarmed! Stay where you are! Stand in the place where you live, now, just ... OK, more REM nonsense at the end there, but you gotta love a Geography song!
Near the end of this video, Dr. Sabine Hossenfelder does note that the whole thing is "vastly more complicated" (14:15) than what she explained here. I can be generous and allow that this means the radiation heat transfer in both directions (inward and outward) within this whole atmosphere and the land cover... ooops, and cloud cover, etc. is taken into account. That is, between everything and everything else.
What if I told you ... what if I told you, though ... that all this modeling is only about the radiation heat transfer and doesn't account for all the climate phenomenon in the Troposphere below? No, God! No, God! Please No!******** Is that sufficient? What if I told you that Dr. Hossenfelder is, in my opinion, no expert on Atmospheric Science, much less Climatology? What she IS, though, is the "What if I told you?" lady to match Bart Simpson's "I didn't do it" guy. She's a popularizer of something, but I'm not buying it.
This was by far Peak Stupidity's longest post EVAH! I will follow up with my discussion, as a repeat of material in posts 6 years go, on how complicated the whole climate modeling idea really is. Sabine Hossenfelder doesn't know the half of it, even if she has somehow been right on the money in this video.
* CO2 is not just sitting there in one layer though, but that's just more of the complications that she glosses over, even in her PhD simplified explanaton.
** Sorry to make fun, Dieter. I can't say I'd be able to give ANY kind of lecture in German.
*** The phenomenon of convection is really a mix of conduction and fluid flow. It gets complicated and unworkable FAST.
**** Spell check doesn't know "Rankine" #SAD
***** A totally different example, this from solid mechanics, might be, "this part sees a bending and torsion loading from ..." Engineers know that mechanic/structural parts don't have eyes, but this is a useful way to discuss things.
****** Oh, and possibly the house walls are warmer than the car, so that portion of radiative heat transfer goes the other way. I know what you're thinking: Criminey!
******* It is much narrower near the poles than toward the equator.
******** I gotta appreciate the Michael Scott clip at 09:02. This is a scene of his reaction on seeing that HR guy Toby Flenderson is not gone from The Office for good after all.