Do a quick experiment:

1. Fill a glass half-full with water
2. Drop a couple of ice-cubes into the glass
3. Measure the water level before the ice melts
4. Measure the water level after the ice melts

Now compare the water level before and after the ice melted, and you’ll find them to be the same. So if melting ice doesn’t increase the water level in your glass–why do melting ice-caps raise the sea-levels of the earth?