Greenland melting will affect many things. It already does. Sea levels are just one.
-> Sea level rise
-> Sea levels will be affected because the liquid water that is generated from melting ice will go into the oceans and the sea levels will rise. If the entire 2,850,000 km cubed (684,000 cubic miles) of ice on greenland were to melt, global sea levels would rise 7.2 m (24 ft). This would swamp most cities and ports, much of the best agricultural land in the world. Click on the image to the right for a cool animation.

-> Excess of Freshwater
-> An excess of freshwater will affect ocean currents and circulation. This in turn would affect regional climate.

->Movement of solids and dissolved materials
-> Meltwater, which moves to the sea under the ice touching the land surface, will move solids or dissolved materials like iron to the ocean. Measurements of the amount of iron in meltwater shows that this will add an amount of iron to the Atlantic Ocean equivalent to that added by airborne dust. This would increase biological activity drastically in the Atlantic.