If you want to prove to a liberal that melting ice will not raise sea level. Put a cube of ice in a glass and then fill the glass with water to the rim. Come back in an hour, the ice will be melted, but the level in the glass will not have risen, in fact it will be slightly lower.
Now, if ice covering land melts and runs into the ocean it could cause levels to rise, but the ice on antartica just keeps getting thicker.
Now, if ice covering land melts and runs into the ocean it could cause levels to rise, but the ice on antartica just keeps getting thicker.