You are correct about the process and there are some here who claim the CO2 does nothing at all, but an argument you frequently see here is that there is no, or almost no positive feedback. A significant portion of equilibrium climate sensitivity (ECS) is the positive feedback that any temperature increase will receive from added water vapor that higher temps put in to the air. Of course no one has ever explained why there WOULDN'T be such feedback but there you go.What the climate deniers ignore is that adding more carbon to the atmosphere does not itself cause heat, but changes how much heat is retained vs radiated away, constantly.
It is an accumulating process.
YesThat is why the earth does not drop to zero degrees every night.
On the order of a couple centuries.And the excess carbon we added will not stop retaining more and more heat for a very long time.
Scientists have made estimates and they are all in that ballpark for CO2. Methane, which absorbs more IR than CO2, fortunately has a shorter atmospheric lifespan of about 12 years.We do not know how long.
We'll, yes we do. That is what the ECS tells us. Have a look at Chapter 3 of the Technical Summary of The Physical Science Basis of the IPCC's AR6 at www.ipcc.ch.And we do not know then what the final temperature will be when it finally reaches equilibrium.
No. I doubt our atmosphere could hold that much water even were the planet at 100C. Eventually, one way or a very unpleasant other, humans will stop burning fossil fuels. Within a few decades, CO2 in the air will start to come down and with it, temperatures. Water vapor decreases and increasing carbonate solubility will both provide some assistance in that direction as well.It may be so hot that eventually all the surface water in the oceans evaporate.