[chiller]

The simpler explanation for we science dummies: A large protuding ice cube weighs more and displaces or pushes surrounding water higher in the glass (or ocean). As the ice melts, the cube weights less, and displaces less. = no change.

An iceberg supported by land, dumped into the ocean (not physically possible) would raise sea levels, but it's a damn big ocean, so ocean rise would be barely measurable even by satellite. Bergs attached but not supported by land won't make a difference.

[TigersEye]

No, it doesn’t weigh more it is less dense. There is a difference. If you freeze one gallon of water it expands and has more than one gallon of volume. It still weighs the same.

[jonascord]

"The simpler explanation for we science dummies: A large protuding ice cube weighs more and displaces or pushes surrounding water higher in the glass (or ocean). As the ice melts, the cube weights less, and displaces less. = no change."

Uhm, no...

Water EXPANDS when it freezes. By about 10%. It's why a can of soda in a freezer will burst. Since a cube of frozen water DISPLACES less of a volume of water than it weighs, it floats. That's why 10% of a cube sticks out of the water.