North and South Polar Ice Caps
Polar ice caps are huge sheets of ice that lie at a planet or moon's poles. Earth has ice caps at both the North and South Pole. The caps don't melt and re-freeze seasonally so they can be 10-13 feet (three to four meters) thick at the North Pole and even thicker at the South Pole (Antarctica). Polar ice caps get less exposure to the sun than the rest of the earth, which results in lower surface temperatures. Polar ice caps can grow and shrink due to climate variation.
Icebergs
Icebergs are pieces of ice that formed on land and float in an ocean or lake. Icebergs come in all shapes and sizes, from ice-cube-sized chunks to ice islands the size of a small country. Icebergs form when chunks of ice calve, or break off, from glaciers, ice shelves, or a larger iceberg. Icebergs travel with ocean currents, sometimes smashing up against the shore or getting caught in shallow waters. When an iceberg reaches warm waters, the new climate attacks it from all sides. On the iceberg surface, warm air melts snow and ice into pools called melt ponds that can trickle through the iceberg and widen cracks. At the same time, warm water laps at the iceberg edges, melting the ice and causing chunks of ice to break off. On the underside, warmer waters melt the iceberg from the bottom up.
Polar Ice Fluctuations
The poles go through cycles of ice advance and retreat every year depending on the season. However, it is the average diminishing ice concentrations that trouble scientists. Presented in the video (link below) are two years of ice concentration data from the NASA QuikSCAT satellite. NOAA uses this data to observe major trends in ice concentration.
