I'm going to keep it simple, Henry's Law has nothing to do with this simple concept. The problem with these types of debates is that the fundamentals and foundations aren't debated first. "... carbon dioxide and other greenhouse gases act like a blanket or a cap, trapping some of the heat that Earth might have otherwise radiated out into space." --- https://news.climate.columbia.edu/2021/02/25/carbon-dioxide-cause-global-warming/ True or False?
Ahh ha, it is a trick question! The answer is Antarctica which is not a country! It releases millions of tons of CO2 into the air through the sublimation of it's ice, where the CO2 is trapped. (Well, I have no idea if that is true, but it reads well.) Cookie for me?
It's true, but recognizing this is not much help in understanding our planets surface temperature. It is a complex, multivariable problem. Temperature affects CO2 concentration, and CO2 concentration affects temperature. So a more important question is, "which is the independent variable, Temperature or CO2?," to which I suppose the best answer is , "It depends." This is a question never satisfactorily addressed by Hansen. Well known atmospheric physicist, Murry Salby, now retired, maintains that our observations fit a relationship between temperature and CO2 concentration much better when Temperature is treated as the independent variable. This would be consistent with Henry's law. Miskolczi has shown that the overall feedback to rising energy, i.e., temperature, in the atmosphere should be negative, whereas Hansen's hypothesis requires that the overall net feedback to rising temperature be positive.* This is a dilemma not yet resolved. I always like to point out that by far the most important greenhouse gas is water. "Anyone who thinks the science of this complex system is settled is in fantasia." - Murry Salby
So, in a system (atmosphere), where there is an initial amount of CO2; and if we increase the CO2 levels, all things being equal, then less heat escapes that system, and therefore, necessarily, the temperature of that system increases. Do you agree?
Yes of course. But ceteris paribus only applies to thought experiments , it can never apply to the Earths Atmosphere.
Heat conservation exists in thought experiments, as well as the real world. I said all things being equal to mean no other changes would be introduced but for the adding of CO2. Other factors are irrelevant. The equation is about the amount of heat entering the system, vs. the amount of heat exiting the system. Heat can only leave the atmosphere via exiting into space. Certainly you realize that if you add heat to any system, the temperature must increase. If the temperature is not increasing, or is decreasing, then we are either not adding heat, or the heat is escaping. Adding CO2 means that that we are adding heat via reflecting more of it back into the system. The above are based on current laws of physics. But, Let's try it this way: Give an example where increasing CO2 levels will not result in more heat being retained by the atmosphere/Earth system.
But this does not apply to our earths atmosphere, does it? Are there any possible real cases where CO2 in the atmosphere could change its concentration and nothing else changes. I don't think so. So if you assume that nothing else changes you will nicely predict something other than what you intended like to predict. There is more than an atmosphere alone. There is also a planet in contact with that atmosphere.Though it seems your statement is essentially correct. Other factors are hugely important! This is why no one has yet successfully modeled the Earth climate. You should, perhaps pose this question to a good atmospheric physicist. My point of view is such a proposition would only be relevant if you could increase CO2 concentration without anything else changing at the same time. But of course adding heat content to the oceans increases atmospheric CO2 and increases cloud formation. The later can not be , as yet, successfully modeled. And so far as I know the debate as to whether clouds are net warming or net cooling has led nowhere, because the answer depends on density altitude and degree of cloud cover. I will leave you with something to ponder*. You know that on a cloudless night at the same sub tropical latitude, inland, well away from large bodies of water, and at identical altitudes, the air temperature above a desert is far lower than the air temperature above a meadow; yet air sampled in both regions, dried and subjected to CO2 analysis will yield quite similar concentrations of CO2 expressed as ppm. Furthermore, the concentration of CO2 in air sampled over both regions and not dried, expressed as ppm will be considerably higher over the desert than over the meadow; yet the temperature over the desert will, again, be considerably lower over the desert than over the meadow. ______________________ *This is as close as I can come, at the moment anyway, to an example of a case where CO2 is at higher concentration, yet the temperature lower. But it does not satisfy your ceteris paribus requirement because another component of the air is changing as well, viz., water vapor. (N.B. CO2, as are all the other components of our atmosphere, except water vapor, is, unless otherwise specified, always expressed as ppm in dry air.)
Addressing one point at a time: Whatever else is happening doesn't change the fact that increasing the CO2, increases the amount of heat that is reflected back to Earth. Again, give us an example where something else happening, will cause the reflective properties of the CO2 molecule to stop reflecting. Ok, two points: It's a system, bounded by the atmosphere. Heat entering the system ... enters the system. This is physics. Nothing can change that. Whatever else is in the system, doesn't change the fact that heat entered the system. The heat will disperse within the system, or escape into outer space. When you run your air conditioning, you don't make cold air, you move heat from one system, your home, to the enclosing system, the atmosphere. The heat didn't vanish. Ok, three points: This is why I said earlier that debates about global warming make little progress: the basics aren't understood by those doing the debating. There are a lot of important factors on the surface. None of them override Thermodynamics and the conservation of heat/energy. Facts: 1. Some heat is caused by the Sun. 2. Some of that heat is reflected into space. 3. CO2 prevents some of that heat from being reflected into space. 4. As CO2 increases, less heat is reflected into space. This happens, period. Nothing on the planet stops the molecule CO2 from reflecting heat. Nothing on the planet stops the Sun from causing heat. This is fundamental to that "important" stuff you speak of. The fundamentals must be understood and agreed upon first.
Please see the example I just posted. An example where increasing the CO2 decreases the amount of heat reflected back to Earth because something else is happening. In other words I am at a loss to find any real case that can satisfy your requirements that nothing else change when CO2 concentration changes! I think this may have something to do with partial pressures. It is going to be hard to get around this problem, but why not try. Be my guest.