With the arrival of diaries at LGF, comes micro-essays. Here’s one that demands some comment:

Well, now. This is a great example of stringing together a number of statements that are sometimes almost right, frequently misleading, and in one case just plain wrong, in order to come to a conclusion that if not outright wrong, is certainly not really supported. And eventually on to an analogy that is so not even wrong, that it deserves an award.

Let’s go through this step by step:

The sun is a giant thermonuclear fire ball that is held together by gravity. Because of its mass and composition, the sun emits light mostly centered around the visible spectrum but with a great deal of IR. Solar spectra have been directly measured. The sun puts out a ton of IR and we even know why it does this. Energy is conserved. As an immediate consequence, if something takes on energy from another source it must manifest it in some way.

It’s not clear what all these disjounted statements are supposed to lead to, but each one, by itself, is kind of more-or-less correct. The part about the light being centered around visible because of mass and composition rather misses the point; the spectrum is entirely a function of the surface temperature, but I don’t know why that was even mentioned, since the other part of that wasn’t: that visible and near-IR is essentially NOT absorbed by the atmosphere, either by CO2 or any of the other “greenhouse” gases.

As an aside, “The sun puts out a ton of IR and we even know why it does this.” is an awfully awful sentence, that’s neither literally accurate nor pretty (GotC, would you allow that in your 8th grade classroom?). I have my doubts that this came from someone who’s ever written a PhD dissertation, although standards might not be what they once were.

CO2, absorbs IR radiation very well. This has been known since 1896. If matter interacts with light, several things can happen. The light can be absorbed. This causes the molecules of the matter to vibrate and do various mechanical motions.

Vibrate and do various mechanical motions? We’re not talking about your s&m stuff. Focus.

Anyway, again, this is true as far as it goes, but there a lot of important detail missing. Very few molecules have absorption spectra covering an entire range of radiation, and no common gases do this. CO2 in particular absorbs as a few specific frequencies, and these bands partially overlap with water vapor among others. So this is almost right, but the part that’s left out is critical. Here’s a reasonably complete picture of what’s absorbing at which wavelengths at actual concentrations in the atmosphere.

Carbon Dioxide is pretty sparse compared to water, and so is methane. Quixote continues:

This is what heat is. If you doubt heating occurs in this way, sit outside on a sunny day. It is cooler in the shade, because you are not absorbing as much light and warming up. If light gets reflected, energy is still conserved. The thing doing the reflection does not heat as a result. The energy comes in and then it goes out.

Pretty basic observation there. I tend to agree that most people understand that the sun makes stuff warm. This I shall not contest.

If the bonds of the molecule are just rightly tuned to the frequency of the incident light, as is the case with CO2 and IR, is that the light is absorbed and then re-radiated out some time later in all directions.

Again, lumping all IR together. Real molecules don’t work like this. In fact, the statement is self-contradictory, because the “just rightly tuned” contradicts the implication that all IR is absorbed by CO2.

That means that IR that was reflected by the Earth’s surface can get caught by CO2 in the atmosphere and re-radiated back down where it has another shot of getting absorbed and heating something.This is called the greenhouse effect.

No. Not even close. Complete misunderestimation of how the greenhouse effect is supposed to work. It isn’t near IR being reflected by the earth’s surface, it’s far IR being radiated outward in respose to being heated by the visible and near IR coming in from the sun, and heating the earth’s surface. Reflection has the opposite effect; it sends the visible and near IR sailing back out the way it came in.

This is a property of the material. If you have more of it, you have more energy trapped in the Earth system and the Earth gets hotter because energy as always, is still conserved. The re-radiated light has a second chance to get absorbed and turned into heat. The more re-radiation you have, the hotter you get. The Earth cools by radiation ultimately also. The real issue is that this alters the rate of heat flow in compared to the rate of heat flow out.

Again, not quite. The point about offering more resistance to the outflow of energy raising the temperature is valid, but it treats the entire atmosphere like a solid glass bubble. In the lowest layer of the atmosphere, the troposphere, where the vast majority of the atmosphere resides, there are other “channels” for energy to move through than just this radiation channel. Specifically, heat can move by radiation, conduction, dry convection, and convection with phase change. By a huge margin, the most effective of these modes is the last one; when you evaporate a pound of water from the surface, physically transport that pound of water vapor to the tropopause (or thereabouts), and then condense it, huge amounts of heat are transported. And this will happen no matter how much greenhouse gas you put into the atmosphere. This heat leaks right through the “greenhouse”. This is not one of the things that they’ve been able to model accurately, but one thing is certain: ignoring it will always exaggerate the heating effect.

Past this point, there is NO debate. There is none. if you get this basic science, then you must conclude that adding more CO2 means trapping more IR.

Not really, for several reasons:

This is one of those statements that is correct, but at the same time bordering on useless. The reason being is that it doesn’t talk about magnitudes, or calculating anything. It’s an answer that implys a question that’s too simple to be useful. The real question isn’t whether there’s an effect, but how significant it is.

Completely missing from all of this is the the whole subject of climate feedback, which is the source of all of the scary scenarios. He’s right about one thing: if you make all these simplifying assumptions, you can calculate a warming. Because the formula is logarithmic, there’s a variable called the “climate sensitivity” that’s expressed in degrees per doubling. And with the simplifying assumptions, it’s a reasonably straighforward calculation. It comes out to 1.1 degrees F for every time you double the CO2 (this also works for methane and other GHGs, but the number is different).
So, how does the IPCC come up with numbers that are three to five times that? With “feedback”. Feedback is the assumption that if you warm the world a degree, that the extra water vapor will add more greenhouse absorption, and cause it to warm a few more degrees. It’s kind of a convenient fudge factor, you get to make it whatever you feel like making it, since the theory is so weak. In fact, there’s no reason why feedback has to even be positive (thus magnifying the effect). It can be negative, thus acting like a thermostat, and there are several theories out there that suggest that what really happens is that water vapor does in fact increase, but ends up as more clouds, reflecting more of that visible and near IR back out into space.

So while the known physics says that there should be some warming, there’s way too much that isn’t understood about tropospheric dynamics and the nature of feedback to say with certainty that the effect will be even noticable, let alone catastrophic. The only way this can be resolved is either with greatly improved models that have actual predictive ability, or with experimental data that can pin the climate sensitivity down with some certainly (which we also haven’t done). And we’re off to the hockey game. This is why the hocky stick and the hidden decline have become such a point of contention. It’s precisely because the physical models are fuldkommen gak.

To believe that adding more CO2 to the atmosphere would not cause warming is like believing that adding three table spoons of salt to your coffee would not alter the taste. These are properties of the materials. They do what they do.

That is one stinker of an analogy. We’re not talking about a measure of the concentration; we know how to do that. We’re talking about the effect that has on temperature. So let me ask the truly analogous question: If you stick a thermometer in a cup of coffee, and add three tablespoons of salt, will the temperatire go up?
The analogy is also a major fail because 385 ppm in a cup is about 0.1 cc, which is like a very small pill. Not three tablespoons.

Now, since the title of this was “Some background on Greenhouse Gases”, perhaps I delved into more detail than was warranted. But it was necessary, because he started out with a title that implied that this was only going to deal with that narrow question, and then he proceeds to draw a breathtakingly broad conclusion (complete with ludicrous analogy). You don’t get to do that. If you’re going to provide an incomplete picture, you don’t get to draw conclusions. Take your pick. Either outline the whole thing, or refrain from drawing conclusions.

Oh, and hi, Reggie.