Many parts of the Arctic were already settled by the Eskimos and other peoples of Mongolic stock when the first European explorers, the Norsemen or Vikings, appeared in the region. Much later the search for the Northwest Passage and the Northeast Passage to reach Asia from Europe spurred exploration to the north. This activity began in the 16th cent. and continued in the 17th, but the hardships suffered and the negative results obtained by early explorers—among them Martin Frobisher, John Davis, Henry Hudson, William Baffin, and William Barentz—caused interest to wane. The fur traders in Canada did not begin serious explorations across the tundras until the latter part of the 18th cent. Alexander Mackenzie undertook extensive exploration after the beginnings made by Samuel Hearne, Philip Turnor, and others. Already in the region of NE Asia and W Alaska, the Russian explorations under Vitus Bering and others and the activities of the promyshlennyki [fur traders] had begun to make the arctic coasts known.
After 1815, British naval officers—including John Franklin, F. W. Beechey, John Ross, James Ross, W. E. Parry, P. W. Dease, Thomas Simpson, George Back, and John Rae—inspired by the efforts of John Barrow, took up the challenge of the Arctic. The disappearance of Franklin on his expedition between 1845 and 1848 gave rise to more than 40 searching parties. Although Franklin was not found, a great deal of knowledge was gained about the Arctic as a result, including the general outline of Canada's arctic coast.
Otto Sverdrup, D. B. MacMillan, and Vilhjalmur Stefansson added significant knowledge of the regions. Meanwhile, in the Eurasian Arctic, Franz Josef Land was discovered and Novaya Zemlya explored. The Northeast Passage was finally navigated in 1879 by Nils A. E. Nordenskjöld. Roald Amundsen, who went through the Northwest Passage (1903–6), also went through the Northeast Passage (1918–20). Greenland was also explored. Robert E. Peary reportedly won the race to be the first at the North Pole in 1909, but this claim is disputed. Although Fridtjof Nansen, drifting with his vessel Fram in the ice (1893–96), failed to reach the North Pole, he added enormously to the knowledge of the Arctic Ocean.
Air exploration of the regions began with the tragic balloon attempt of S. A. Andrée in 1897. In 1926, Richard E. Byrd and Floyd Bennett flew over the North Pole, and Amundsen and Lincoln Ellsworth flew from Svalbard (Spitsbergen) to Alaska across the North Pole and unexplored regions N of Alaska. In 1928, George Hubert Wilkins flew from Alaska to Spitsbergen. The use of the "great circle" route for world air travel increased the importance of Arctic, while new ideas of the agricultural and other possibilities of arctic and subarctic regions led to many projects for development, especially in the USSR.
In 1937 and 1938 many field expeditions were sent out by British, Danish, Norwegian, Soviet, Canadian, and American groups to learn more about the Arctic. The Soviet group under Ivan Papinin wintered on an ice floe near the North Pole and drifted with the current for 274 days. Valuable hydrological, meteorological, and magnetic observations were made; by the time they were taken off the floe, the group had drifted 19° of latitude and 58° of longitude. Arctic drift was further explored (1937–40) by the Soviet icebreaker Sedov. Before World War II the USSR had established many meteorological and radio stations in the Arctic. Soviet activity in practical exploitation of resources also pointed the way to the development of arctic regions. Between 1940 and 1942 the Canadian vessel St. Roch made the first west-east journey through the Northwest Passage. In World War II, interest in transporting supplies gave rise to considerable study of arctic conditions.
After the war interest in the Arctic was keen. The Canadian army in 1946 undertook a project that had as one of its objects the testing of new machines (notably the snowmobile) for use in developing the Arctic. There was also a strong impulse to develop Alaska and N Canada, but no consolidated effort, like that of the Soviets, to take the natives into partnership for a full-scale development of the regions. Since 1954 the United States and Russia have established a number of drifting observation stations on ice floes for the purpose of intensified scientific observations. In 1955, as part of joint U.S.-Canadian defense, construction was begun on a c.3,000-mi (4,830-km) radar network (the Distant Early Warning line, commonly called the DEW line) stretching from Alaska to Greenland. As older radar stations were replaced and new ones built, a more sophisticated surveillance system developed. In 1993 the system, now stretching from NW Alaska to the coast of Newfoundland, was officially superseded by the North Warning System.
With the continuing development of northern regions (e.g., Alaska, N Canada, and Russia), the Arctic has assumed greater importance in the world. During the International Geophysical Year (1957–58) more than 300 arctic stations were established by the northern countries interested in the arctic regions. Atomic-powered submarines have been used for penetrating the Arctic. In 1958 the Nautilus, a U.S. navy atomic-powered submarine, became the first ship to cross the North Pole undersea. Two years later the Skate set out on a similar voyage and became the first to surface at the Pole. In 1977 the Soviet nuclear icebreaker Arktika reached the North Pole, the first surface ship to do so.
In the 1960s the Arctic became the scene of an intense search for mineral and power resources. The discovery of oil on the Alaska North Slope (1968) and on Canada's Ellesmere Island (1972) led to a great effort to find new oil fields along the edges of the continents. In the summer of 1969 the SS Manhattan, a specially designed oil tanker with icebreaker and oceanographic research vessel features, successfully sailed from Philadelphia to Alaska by way of the Northwest Passage in the first attempt to bring commercial shipping into the region.
In 1971 the Arctic Ice Dynamics Joint Experiment (AIDJEX) began an international effort to study over a period of years arctic pack ice and its effect on world climate. In 1986 a seasonal "hole" in the ozone layer above the Arctic was discovered, showing some similarities to a larger depletion of ozone over the southern polar region; depletion of the ozone layer results in harmful levels of ultraviolet radiation reaching the earth from the sun. In the 21st cent. increased interest in the resources of the Arctic Ocean, prompted by a decrease in permanent ice cover due to global warming, have led to disputes among the Arctic nations over territorial claims. Practically all parts of the Arctic have now been photographed and scanned (by remote sensing devices) from aircraft and satellites. From these sources accurate maps of the Arctic have been compiled.