Given recent threads, there seem to be folks here who have crunched through quite some published materials on 'global warming'. So I'd be interested to hear if any of these publications people have read have addressed one conundrum I've never really been satisfied with, in all the discussion on atmospheric warming:
The 'greenhouse effect' is clearly a misnomer because trapping in IR radiation is not how a greenhouse works. A greenhouse works by trapping warmed air. You regulate the temperature of a greenhouse by opening the window at the top to let the hot air out.
The conundrum, then, is that the atmosphere does actually works like this. The atmosphere is not a sealed box that just gets hotter and hotter, instead the atmosphere is free to expand upwards. In fact, you could say the 'greenhouse effect' is a cooling effect by letting the hot air escape because this is a greenhouse's MO!
Consider for a moment how planets retain an atmosphere; gravity matches the thermal excitation of the gases of the atmosphere to retain them, else the atmosphere is lost (loss of mass) or the atmosphere is pulled in closer (increase in pressure), and because the atmosphere can expand without limit, pressure will simply vary so as to meet an equilibrium temperature against which the gravity is balanced.
The logical corollary being is that the equilibrium temperature of a planet is a function of the mass of the atmosphere and the strength of the gravitational field. There may be regional and altitude deviations to that, but overall if the atmosphere gets hotter it will expand and the height of the atmosphere increase until the temperature comes down to a point where diffusion by thermic agitation then balances with the planet's gravity.
Ergo, atmospheric warming can only be localised in characteristic because the atmosphere will expand to compensate for any increases in temperature, tending towards a temperature equilibrium. This will only change if the mass of the atmosphere, or gravity, changes.
Could someone please disabuse me of this notion?
The 'greenhouse effect' is clearly a misnomer because trapping in IR radiation is not how a greenhouse works. A greenhouse works by trapping warmed air. You regulate the temperature of a greenhouse by opening the window at the top to let the hot air out.
The conundrum, then, is that the atmosphere does actually works like this. The atmosphere is not a sealed box that just gets hotter and hotter, instead the atmosphere is free to expand upwards. In fact, you could say the 'greenhouse effect' is a cooling effect by letting the hot air escape because this is a greenhouse's MO!
Consider for a moment how planets retain an atmosphere; gravity matches the thermal excitation of the gases of the atmosphere to retain them, else the atmosphere is lost (loss of mass) or the atmosphere is pulled in closer (increase in pressure), and because the atmosphere can expand without limit, pressure will simply vary so as to meet an equilibrium temperature against which the gravity is balanced.
The logical corollary being is that the equilibrium temperature of a planet is a function of the mass of the atmosphere and the strength of the gravitational field. There may be regional and altitude deviations to that, but overall if the atmosphere gets hotter it will expand and the height of the atmosphere increase until the temperature comes down to a point where diffusion by thermic agitation then balances with the planet's gravity.
Ergo, atmospheric warming can only be localised in characteristic because the atmosphere will expand to compensate for any increases in temperature, tending towards a temperature equilibrium. This will only change if the mass of the atmosphere, or gravity, changes.
Could someone please disabuse me of this notion?