ice sheet
The ice sheet covering the Antarctic continent has an average depth of 2.2 kilometers, with a depth of five kilometers in places! It covers 95 percent of the continent and extends several hundred kilometers past the continental shelf. When it is at its maximum extent, in September of every year, the ice covers an area of 20 million square kilometeres - an area bigger than South America!
The antarctic ice sheet locks up over 90 percent of the earth's fresh water reserves. If it ever melted, global sea levels would rise by 75 meters.
The Antarctic ice sheet plays a crucial role in controlling the earth's heat balance. It reflects more than 80 percent of the sun's rays and acts as a barrier between the relatively warm ocean and the cold air during winter, thereby preventing the loss of heat from the sea. Ice only freezes the fresh water component of seawater. Saltier and therefore denser seawater sinks to the ocean floor. This drives ocean currents in the southern hemisphere and keeps the world significantly cooler.
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