the physics of carbon had shown how carbon molecules, water vapour and nitrous oxides absorb heat energy and re-radiate that energy. carbon dioxide was demonstrated 150 years ago to prove the effect of heat radiation.
you're right that water vapour is not a human made contributor to global warming and climate change.nor is it able to be controlled. it is dependent on the effect of GHGs and the rising atmospheric temperature. if we can manage to reduce GHGs in the atmosphere there will be a slow reduction in the atmospheric temperature. the reduction in GHG emissions should have been effective but for the development needs of China and India and the hasty manner they've increased their GHG emissions.
a lower atmospheric temperature will result in less water vapour development.
