[GilesB]

“...carbon dioxide, the chief greenhouse gas.”

A LIE! The chief “greenhouse gas” is H2O! The difference is so extreme that the so-called father of global warming stated something to the effect that you would increase global temperatures more by spitting than by driving your car for a year.

[Ben Ficklin]

Water vapor condenses, CO2 doesn't. So, water vapor is part of the hydrologic cycle, which like the carbon cycle, can be complicated, especially when the hydrologic cycle and the carbon cycle intertwine.

If water vapor condenses, falls as rain, absorbed by the soil, taken in by a plant's roots to combine with the carbon the plant took from the atmosphere to create things like cellulose and lignin, which if burned/decomposed, release CO2 and water vapor to the atmosphere.

It could be a plant that grew in the spring then burned in the summer or a plant that grew in a far back geologic period, was stored in the earth, mined, then burned to generate electricity.