Losing on Home Turf : The polar bear is playing a losing game for survival. But as global warming heats up polar bear territory, nobody wins.

Arctic Facts

There is no single, commonly accepted southern boundary to the Arctic. The Arctic Circle—the line above which the sun does not set at the peak of summer or rise at the height of winter—is one. On land, the treeline—where forest gives way to tundra—is another. In the maritime Arctic, the most commonly accepted boundary is the southern limit of winter pack ice.

The Arctic Ocean is generally considered to be that part of the northern ocean that is more or less permanently covered by sea ice, an area of approximately 5.5 million square miles, or slightly less than 1.5 times the size of the United States.

The average depth of the Arctic Ocean is about 3,500 feet its greatest depth is 17,850 feet, just north of the Chukchi Sea.

The name “Arctic” is from the Greek, Arctos, for bear—so named the constellations, the Great Bear and Little Bear (or “Ursa Major” and “Ursa Minor”) that are ever-present in the northern sky.

Many Ancient Greeks believed the Arctic was inhabited by the Hyperboreans, who lived “beyond the north wind.” The poet Pindar, writing about two and a half thousand years ago, held “feasts out of sheer joy. Illnesses cannot touch them, nor is death foreordained for this exalt race.”

The North Pole is, of course, the most northerly point on the globe. But there are three other “poles” in the Arctic: the Magnetic North Pole, a wandering location, which is the point to which a compass needle points; the Geomagnetic North Pole, the north end of the axis of the geomagnetic field that encompasses earth; and the Northern Pole of Inaccessibility, which is the point in the Arctic Ocean that is farthest from land.

The most northerly parts of the Arctic are warmed by the waters of the Arctic Ocean, and so are not always the coldest areas in the Arctic. In fact, the coldest temperature ever recorded in the northern hemisphere is -90F in the Siberian town of Verkhoyansk, just north of the Arctic Circle.

Although the Arctic can indeed be very, very cold, it is, on average, far less cold than Antarctica, which is super-cooled by the giant ice cap that covers the frozen continent. The average annual temperature at the South Pole is -60F, and the coldest temperature ever recorded in the Antarctic—ever recorded anywhere on the surface of the Earth—is -129.9F.

As a result, although the Arctic is often considered to be cold, barren, and lifeless, it supports much more than does the Antarctic. For example, whereas the entire continent of Antarctica is host to just two species of flowering plant, Greenland alone boasts 40. Antarctica has no land mammal species; the Arctic has more than 40, including such giants as musk oxen, moose, and bears.

Indeed, during the Arctic summer, when the days are long and the region is bathed in solar energy, the region comes alive. On land, flowers bloom, multitudes of insects fill the air, and birds and mammals undertake great migrations northward. In the cold seas, too, great migrations begin: walruses, belugas, seals, and bowhead and gray whales all head north to feed in the bountiful arctic waters.