Climate change poses the greatest danger to the Arctic and its wildlife. The Arctic is warming twice as fast as any place on the planet. Warmer seas are changing the range and seasonal cycles of Arctic fisheries. Some fish are moving to deeper, cooler waters, by moving northward.

Geography. The Arctic Circle is roughly 16,000 km (9,900 mi) in circumference. The area north of the Circle is about 20,000,000 km2 (7,700,000 sq mi) and covers roughly 4% of Earth’s surface. The Arctic Circle passes through the Arctic Ocean, the Scandinavian Peninsula, North Asia, Northern America, and Greenland.

: the parallel of latitude that is approximately 66¹/₂ degrees north of the equator and that circumscribes the northern frigid zone.

Arctic will see ice-free summers by 2050 as globe warms, study says. Sea ice is frozen ocean water that melts each summer, then refreezes each winter. Sea ice affects Arctic communities and wildlife such as polar bears and walruses.

Three main interrelated issues regarding the Arctic environment are climate change, changes in biological diversity, and the accumulation of toxic substances. The effects of these changes are becoming increasingly evident in the North.

First, the bad news: The Arctic is melting much faster than expected, and could even be ice-free in summer by the late 2030s, a report from the Arctic Council’s Arctic Monitoring and Assessment Program suggests. Previous studies had forecast an ice-free North Pole in summer by mid-century.

Ice is more reflective and less absorbent of sunlight than land or the surface of an ocean. When ice melts, it typically reveals darker areas of land or sea, and this results in increased sunlight absorption and associated warming. Polar amplification is much stronger in the Arctic than in Antarctica.