Arctic Ocean

The Arctic Ocean occupies the area around the North Pole. North America, Eurasia and Greenland almost encircle it, and numerous islands and marginal seas form part of its complex coastline. It is Earth's smallest ocean, but contains broad continental shelves as well as deep basins. The shallow Bering Strait links it to the Pacific, while Fram Strait and other northern passages connect it to the Atlantic. River inflow, precipitation, sea-ice formation and melting all influence the salinity and movement of its waters.

Sea ice is frozen ocean water, not ice formed on land. Arctic ice generally grows as cold and darkness return in autumn and winter, then retreats as temperatures rise; the smallest annual extent is usually reached near the end of summer. Ice cover reflects much of the Sun's energy and limits exchanges of heat between ocean and atmosphere. When bright ice gives way to darker open water, more solar energy is absorbed, reinforcing regional warming. NASA satellite records show a long-term decline in September Arctic sea-ice extent; the agency's indicator reports a rate of 12.2 percent per decade relative to the 1981–2010 average.

Arctic marine ecosystems are shaped by cold water, seasonal light and the presence or absence of sea ice. Ice provides breeding, shelter and feeding habitat for some animals, and nearby communities rely on ice-related knowledge and conditions for travel, hunting and cultural practices. The ocean is also important to global systems: sea ice affects exchanges of heat and moisture, while the formation of dense, salty water contributes to ocean circulation. These effects connect changes in the Arctic to processes well beyond the region.

Shrinking sea ice is changing access to parts of the Arctic Ocean. Longer or more accessible open-water periods may create opportunities for navigation and economic activity, but they can also raise risks such as shipping accidents and oil spills in a remote region where response is difficult. The Arctic Council identifies marine pollution, sustainable shipping, search and rescue, and cooperation on environmental risk as important issues. Monitoring ice, understanding marine ecosystems and coordinating stewardship are therefore central to managing the ocean's changing conditions.