The Greenland ice sheet is a vast expanse of ice covering roughly 1.7 million square kilometers, making it the second-largest ice body in the world after the Antarctic ice sheet. It plays a crucial role in regulating global sea levels, as it holds about 7 meters of potential sea-level rise if it were to melt completely. The ice sheet is primarily composed of compacted snow and is constantly changing due to processes like melting and calving. Scientists study the Greenland ice sheet to understand climate change impacts, as its melting contributes to rising sea levels and affects ocean circulation patterns.