Increase in temperature. I am not exactly sure what you're looking for but basically water vapour in the air has to do with evaporation of water from the surroundings so it will definitely have to do with the increase in global temperatures brought by global warming
The oceanic crust consists of a volcanic lava rock called basalt. Basaltic rocks of the ocean plates are much denser and heavier than the granitic rock of the continental plates. Because of this the continents ride on the denser oceanic plates.
