Grounded ice is ice resting on the ground rather than floating. The melting of floating ice will not change sea level: the mass of this ice is equal to that of the water it displaces (watch the water level in a cup of floating ice cubes as they melt). For comparison, globally ice (both grounded and floating) represents about 2% of the world's water, with about 1,350,000,000 km3 of water in the oceans.