PV = nRT
This means that when pressure goes down, with equal volume and mass, temperature must go down. As pressure and temperature go down, this also lowers the air’s ability to hold water vapor in solution. Once the air is at saturation, any further reduction in either temperature or pressure will cause the water vapor to be expelled from solution, and changes the water phase from gaseous to liquid.
If we can remember that chemistry experiment with the beaker of water over the bunsen with a thermometer stuck in it, then we’d remember that as energy is being applied to the water, it’s temperature rises but only up to 100ºC. At this point, the energy is used to convert liquid water at 100ºC into gaseous water at 100ºC. Only when all the water is in it’s vapor form will the temperature start to rise again. The energy used to change waters to vapor is released back again when it condenses.
Back to our air parcel now, Here’s an infrared satellite photo of the USA. We can plainly see where water vapor is being actively converted to liquid rain, but we’re only seeing a part of the energy release, that which is escaping out into space. A part of the energy is used to lower the pressure, which causes more water to condense, releasing more energy, lowering the pressure …
… and the thing runs away, with basically only friction slowing it down. This is a Positive Feedback Mechanism, the mere act of condensing water vapor cause more water vapor to condense. Normally, the energy to bring water into it’s vapor form comes from the sun. We can make an atmospheric energy budget with just the sun’s input. However, the energy released when condensing water vapor from combustion … well this energy DIDN’T come from the sun, it comes from breaking the carbon bonds in whatever fossil fuel we’re burning.
I repeat my question, why is this energy ignored?
Off the top of my head some of the other sources “disrupting the CO[sub]2[/sub] equilibrium” would be the sun burns hotter today than during the Carboniferous, the actual composition of the atmosphere was different (35% O[sub]2[/sub]) … but the big one is the free flow of waters between the oceans. Once Central America blocked the Equatorial Pacific from the Atlantic, we plunged into a major Ice Age, about 30 million years ago. It’s just a theory about cause-and-effect, but that is something that would change CO[sub]2[/sub] levels.
The phrase “CO[sub]2[/sub] equilibrium” bothers me, I look at the ice core data and I see a sine wave, 100,000 year period and we are currently at a peak. There’s a scientific reason why this forms a wave, and not a straight horizontal line. Until we know why CO[sub]2[/sub] goes up and down like this, we’re in no position to say this will never go down again.
Why, exactly, did CO[sub]2[/sub] concentrations go down 20,000 years ago?
Try2B Comprehensive, thank you for respecting the First Law of Thermodynamics, I thought I was the only one here. I can’t even come up with a Pit-worthy name to call you.