The point I made was with regard to the Antarctic and Greenland ice
sheets. I posed the question about what happens to the water level
when an ice cube is placed in a glass which is then filled to the brim
and the ice melts. The correct answer is the water level drops because
the space occupied by the ice is greater than that occupied by the
water it contains. Water expands when it freezes.
But the ice is floating in the water. The extra space that the frozen water takes up is, by Archimedes principle, exactly the volume that sticks out of the water. So the water level doesn’t change.