Maybe someone can better explain this theory to me. If rising mean temperatures on Earth will cause the ice caps to melt, wouldn't that heat also cause more of the liquid water to vaporize and remain in the atmosphere in greater quantities, thereby LOWERING sea levels? And wouldn't the increased cloud cover serve to lower surface temperatures, thereby counteracting the "warming" effect to a ertain degree? And what about the fact that frozen water in the ice caps actually takes up greater volume than it would as a liquid? Melting that ice may actually reduce the displacement of the sea water, assuming that most of the ice is below sea level already.
The amount of evaporation of the oceans is largely a product of the surface area that the oceans occupy. It is true that a melting of the ice caps would increase the surface area of the oceans, but not by enough to cause a significant increase in the amount of atmospheric H20 levels. Not enough to counteract the increased temperatures caused by the greenhouse effect.
I think this mostly makes sense, and you've thought it through.
I think it may happen. the constant melting of glaciers in himalaya is a proof of this.