Query: “Ice-free means the central basin of the Arctic will be ice-free

Relevant passages:
Arctic Ocean <=SEP=> The Arctic Ocean is the smallest and shallowest of the world 's five major oceans . The International Hydrographic Organization ( IHO ) recognizes it as an ocean , although some oceanographers call it the Arctic Mediterranean Sea or simply the Arctic Sea , classifying it a mediterranean sea or an estuary of the Atlantic Ocean . Alternatively , the Arctic Ocean can be seen as the northernmost part of the all-encompassing World Ocean .   Located mostly in the Arctic north polar region in the middle of the Northern Hemisphere , the Arctic Ocean is almost completely surrounded by Eurasia and North America . It is partly covered by sea ice throughout the year and almost completely in winter . The Arctic Ocean 's surface temperature and salinity vary seasonally as the ice cover melts and freezes ; its salinity is the lowest on average of the five major oceans , due to low evaporation , heavy fresh water inflow from rivers and streams , and limited connection and outflow to surrounding oceanic waters with higher salinities . The summer shrinking of the ice has been quoted at 50 % . The US National Snow and Ice Data Center ( NSIDC ) uses satellite data to provide a daily record of Arctic sea ice cover and the rate of melting compared to an average period and specific past years .

Arctic Circle <=SEP=> The Arctic Circle is the most northerly of the abstract five major circles of latitude as shown on maps of the Earth . It marks the northernmost point at which the noon sun is just visible on the northern winter solstice and the southernmost point at which the midnight sun is just visible on the northern summer solstice . The region north of this circle is known as the Arctic , and the zone just to the south is called the Northern Temperate Zone . North of the Arctic Circle , the sun is above the horizon for twenty-four continuous hours at least once per year ( and therefore visible at midnight ) and below the horizon for twenty-four continuous hours at least once per year ( and therefore not visible at noon ) ; this is also true within the equivalent polar circle in the Southern Hemisphere , the Antarctic Circle .   The position of the Arctic Circle is not fixed ; as of , it runs north of the Equator . Its latitude depends on the Earth 's axial tilt , which fluctuates within a margin of 2 ° over a 40,000-year period , due to tidal forces resulting from the orbit of the Moon . Consequently , the Arctic Circle is currently drifting northwards at a speed of about 15 m per year .

North America <=SEP=> North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere . It can also be considered a northern subcontinent of the Americas . It is bordered to the north by the Arctic Ocean , to the east by the Atlantic Ocean , to the west and south by the Pacific Ocean , and to the southeast by South America and the Caribbean Sea .   North America covers an area of about 24,709,000 square kilometers ( 9,540,000 square miles ) , about 16.5 % of the earth 's land area and about 4.8 % of its total surface .  North America is the third largest continent by area , following Asia and Africa , and the fourth by population after Asia , Africa , and Europe .   In 2013 , its population was estimated at nearly 565 million people in 23 independent states , or about 7.5 % of the world 's population , if nearby islands ( most notably the Caribbean ) are included .   North America was reached by its first human populations during the last glacial period , via crossing the Bering land bridge approximately 40,000 to 17,000 years ago . The so-called Paleo-Indian period is taken to have lasted until about 10,000 years ago ( the beginning of the Archaic or Meso-Indian period ) . The Classic stage spans roughly the 6th to 13th centuries . The Pre-Columbian era ended with the transatlantic migrations and the arrival of European settlers during the Age of Discovery and the Early Modern period . Present-day cultural and ethnic patterns reflect different kind of interactions between European colonists , indigenous peoples , African slaves and their descendants . European influences are strongest in the northern parts of the continent while indigenous and African influences are relatively stronger in the south . Because of the history of colonialism , most North Americans speak English , Spanish or French and societies and states commonly reflect Western traditions .