Ice sheets are in the ocean anyway so melting makes no difference its just ice cubes in glass of water.
Don't confuse north polar ice with the ice sheets. Most of the ice (90%) is in ice sheets several miles thick over Antarctica. The reason the Greenland ice sheet is considered significant is again because it rests on land, not already in the water, and its flow into the Gulf Stream is a factor in that currents thermally driven flow. Significant alteration of the Gulf Stream's flow has importance to Europe because, if you look at a globe, their location farther north would have an otherwise cooler clime.