Archimedes' principle says that ice displaces an equal amount of water. That's why, if you put ice in a glass, then fill it to the top with water, the glass won't overflow when the ice melts.
Land-based ice (think Greenland or Antarctica) is more problematic. However, everything that I've read regarding Antarctica says that the ice cap - other than in several small places on the periphery, which coincidentally is what the eco-nuts are measuring - is getting thicker.
I read an article on FR about icemelt in Greenland.... typically hyperbolic..."millions of gallons of meltwater a week in the summer" or somesuch nonsense. I ran the numbers and it amounted to a wet weather stream that wouldn't even get the tops of your shoes wet.
Hard to sort the wheat from the chaff on this one. Lots of good posts right here on FR, though.
I think that I have heard that the ice restraining the WAIS, West Antarctic Ice Sheet, is breaking up. This will allow ice to flow into the ocean at greater rates. I have also seen it suggested that there may be active vulcanism under the ice sheet that melts the ice resulting in water that lubricates the bottom of the sheet and causes greater flow. When the ice sheet enters the ocean and melts it would raise sea levels.
If this really becomes a problem and we lose say, Florida, then we dig a trench at the northern end of the great rift vally in Africa and flood it. Central Africa is pretty dry and I suspect that the inhabitants would probably be happy to get some fish in their diet and a little rain from the new inland ocean.