The primary geographic feature of Greenland is its vast ice sheet, which covers about 80% of the island's surface. This ice sheet is one of the largest in the world and plays a critical role in global sea-level regulation. Greenland's geography is primarily characterized by its remote, icy expanse, with rugged coastlines and fjords. While largely inhospitable, the island also features some tundra and coastal areas where a limited number of communities exist. The melting of the ice sheet due to climate change is a significant environmental concern.