Sea ice is frozen seawater that floats on the ocean surface. It forms in both the Arctic and the Antarctic in each hemisphere’s winter, and it retreats, but does not completely disappear, in the summer. It plays an important role for the climate and ecosystems. The extent and thickness of sea ice covering the Arctic ocean is significantly decreasing. The actual extent can be seen at: decreasing.
From album: Sea Ice, Icebergs, Glaciers, Snow and Permafrost in the Arctic Region