There are a number of greenhouse gases. The one we mainly talk about in the climate context is CO2, but methane and water vapor are among the others. The change in the concentration of those gases in the atmosphere over the last century and a half is the biggest contributor to the unprecedented warming we've been seeing.
No gas or vapor has the capability of warming the Earth. You can't create energy out of nothing. You are still ignoring the 1st law of thermodynamics.
The way they work is that they have resonance frequencies in the infrared spectrum. Because of that, they tend to absorb radiation in that range, which otherwise would have passed into space.
You cannot trap light. Light has no temperature.
The energy is being created within the sun, as a byproduct of nuclear fusion.
Nuclear fusion IS energy.
It then travels to us as light. When it hits the Earth, some gets absorbed and then re-radiated in the infrared spectrum.
Light is utterly destroyed when it absorbed. It is not re-radiated.
Not all photons are the same. You are ignoring Planck's laws.
What's going wrong is that the greenhouse gas increases in our atmosphere have lowered the rate at which that infrared light is escaping the Earth, altering the eventual equilibrium point at which outflows will again match inflows of energy... an equilibrium point that is now already going to be far above anything seen since the dawn of civilization, and which is continuing to increase over time.
You cannot trap light. You are ignoring the Stefan-Boltzmann law now as well as the 2nd law of thermodynamics.
That will be environmentally devastating.
Like many religions, you have to have your Doomsday preaching.
That's why these are talked about as greenhouse gases
No such thing, except as a religious artifact.
-- they are somewhat analogous to the way a greenhouse works,
A greenhouse does not trap light.
where the rate at which energy from the sun leaves an area can be decreased, resulting in that area warming up until it hits a new equilibrium point (where its temperature is high enough that out-bound radiation again matches in-bound). A greenhouse can be much warmer than the surrounding area through that process.
A greenhouse is warmer because it reduces heat, specifically convective heat. An atmosphere cannot do that.
Yet we know how much is flowing out of Lake Meade and there hasn't been a change that would account for the gigantic drop in levels,
Yes there is. Usage has increased steadily through the years until it now easily exceeds available water capacity of the Colorado river.
nor has the upstream use change been enough to account for it.
Yes it has.
What's accounting for it is a megadrought,
Record snows are not a drought. The term 'megadrought' is a meaningless buzzword.
which has resulted in far less precipitation hitting that watershed,
Record snows are not less precipitation.
decreasing how much is flowing into the lake.
Usage is decreasing how much flows into and out of the Lake.
This also involves the issue of in-flows not matching out-flows, though in this case it's that in-flows have declined to the point where existing out-flows now greatly exceed them.
Now you are ignoring Thenivin's law. The Colorado river has a flow. The lake is just a buffer. It does NOT change the total flow.