Polar ice caps are dome-shaped sheets of ice that feed ice to other glacial formations, such as ice sheets, ice fields, and ice islands. They remain frozen year-round, and they serve as sources for glaciers that feed ice into the polar seas in the form of icebergs. The polar ice caps are found in the north and south poles and their surrounding territory, including the entire continent of Antarctica in the south, the Arctic Ocean, the northern part of Greenland, parts of northern Canada, and bits of Siberia and Scandinavia also in the north. They serve as reservoirs for vast amounts of the earth’s water. Hydrologists suggest that three-quarters of the world’s freshwater is frozen at the North and South Poles. Recently observed change in Arctic temperatures and sea ice cover may be a harbinger of global climate changes to come.