The Arctic Ocean is the smallest, shallowest and coldest of the world’s five major oceans, spanning approximately 14 million square kilometres around the North Pole.
Extending south to roughly 60°N and surrounded by Eurasia and North America, the Arctic Ocean remains mostly covered by sea ice year-round, with near-complete coverage in winter. Its surface temperature and salinity vary seasonally as ice melts and refreezes. Because of low evaporation, heavy freshwater inflow from rivers and limited connection to other oceans, it has the lowest average salinity of the five major oceans. The International Hydrographic Organization recognises it as a full ocean, though some oceanographers have called it the Arctic Mediterranean Sea or described it as an estuary of the Atlantic. Sea ice extent has declined sharply in recent decades—the US National Snow and Ice Data Center reports summer ice shrinkage of around 50 per cent, with September 2012 marking a record minimum 49 per cent below the 1979–2000 average.
