There are no dumb questions :-), but no, this is not what will happen. For one thing, the ice that floats around in sea displaces exactly as much water as ice (

There are no dumb questions :-), but no, this is not what will happen. For one thing, the ice that floats around in sea displaces exactly as much water as ice (uses the same 'water volume') as it will as water. (Almost, because the water volume per mass will actually increase with increasing temperatures, which is quite a significant effect). However, a large amount of ice is on land, where it doesn't contribute to ocean volume. If it were to melt that would be a major contributor to sea level rise. Also, the average humidity is quite stable on earth, and any excess water that evaporates into the atmosphere quickly rains out again. Furthermore, the amount of water in the atmosphere is very small in comparison to the amount of water in the oceans. (See e.g. here: http://water.usgs.gov/edu/watercycleatmosphere.html http://water.usgs.gov/edu/watercycleatmosphere.html). So it is very difficult to imagine that an increased humidity would have a significant effect on the sea level.