Ice is less dense, but because it is less dense, some of the ice is above the water level.
So when ice in water melts, the sea level remains exactly the same.
You can check this yourself by putting some ice in a glass of water and marking the water level before and after the ice melts.
“Ice is less dense, but because it is less dense, some of the ice is above the water level.
So when ice in water melts, the sea level remains exactly the same.”
Oh. Never mind.