An ice sheet is a mass of glacial land ice extending more than 50,000 square kilometers (20,000 square miles). Currently, there are important ice sheets on Earth which cover most of Greenland and Antarctica. These two ice sheets contain more than 99 percent of freshwater ice on Earth. The Antarctic Ice Sheet expands merely 14 million square kilometers (5.4 million square miles) and contains 30 million cubic kilometers (7.1 million cubic miles) of ice. The Greenland Ice Sheet extends about 1.7 million square kilometers (656,000 square miles), covering most of the island of Greenland (NSIDC).
The Polar Regions are essential drivers of the world’s climate. When global temperature raises, the increase in the ocean heat content, dark meltwater pools absorb warmth from the sea. Fresh water flows into the sea, changing ocean currents and the living conditions for marine organisms. Data from NASA’s Grace Satellites demonstrate that the land ice sheets in both Antarctica and Greenland are shrinking. Since 2002, The continent of Antarctica has been losing about 134 billion metric tons of ice per year, meanwhile, the Greenland ice sheet has been losing an estimated 287 billion metric tons per year (NASA)