The Arctic has a normal melting cycle in which about half of the ice pack <a href= http://www.livescience.com/php/video/player.php?video_id=arctic_ice_cap target=new>disappears</a> in the summer, only to grow back to the size of the United States during the winter. Still, an alarming recent study determined that the 2-mile-thick ice sheet in <a href= http://www.livescience.com/environment/051116_greenland_melts.html target=new>Greenland is melting</a> so rapidly that half of it could be gone by the end of the century. Other studies have found that the entire Arctic could be <a href= http://www.livescience.com/environment/050823_ice_free.html target=new>ice-free during summer</a> in a few decades. Lately, research has also found that the Antarctic is also <a href= http://www.livescience.com/php/multimedia/imagegallery/igviewer.php?gid=42 target=new>losing ice</a>, which if all melted (no one expects this to happen anytime soon), would cause sea levels to rise roughly 200 feet.
Being primarily a thin layer of ice, the arctic is very sensitive to <a href= http://www.livescience.com/climate/ target=new>changing climate</a> conditions. Warmer temperatures during the <a href= http://www.livescience.com/environment/070430_shrinking_ice.html target=new>summer months</a> cause the 12 to 15 feet thick ice sheet to melt and break apart. Last year, researchers reported for the first time that <a href= http://www.livescience.com/environment/060920_arcticice_opening.html target=new>cracks in the ice</a> had reached all the way to the North Pole.
While the Antarctic has an <a href= http://www.livescience.com/environment/ap_051207_ozone_hole.html target=new>ozone hole</a> that has grown to about three times the size of the United Statesâ€™ land mass, the Arctic is <a href= http://www.livescience.com/environment/ap_050302_ozone_update.html target=new>losing ozone coverage</a> as well. In truth, there is no actual hole; the "hole" is a region of severely depleted ozone, a chemical that helps protect the planet from harmful solar radiation. <a href= http://www.livescience.com/environment/ap_ozone_warning_050131.html target=new>Ozone losses</a> in the Northern Hemisphere are lower than in the Southern because warmer Arctic temperatures limit the formation of polar stratospheric clouds that destroy ozone. But temperatures in the stratosphere, high above the Arctic, have gradually cooled over the last decade, resulting in increased <a href= http://www.livescience.com/environment/050301_ozone_thinning.html target=new>ozone loss</a>.
The Antarctic is so cold that the <a href= http://www.livescience.com/environment/060810_antarctic_precip.html target=new>snow</a> never melts in many areas of the continent. The region's average temperature is about -56 degrees Fahrenheit (-49 degrees Celsius), making it the coldest climate on earth. In contrast, the Arctic's average <a href= http://www.livescience.com/environment/060913_arctic_ice.html target=new>winter</a> temperature is -29 degrees Fahrenheit (-34 degrees Celsius), but it gets warmer in the summer. The lowest temperature ever recorded on Earth was -128 degrees Fahrenheit (-89.6 degrees Celsius), recorded July 21, 1983, at the Vostok Station located near the South Geomagnetic Pole.
Every <a href= http://www.livescience.com/environment/051222_christmas_tree.html target=new>Christmas</a>, thousands of letters mailed to Santa Claus do make it to the North Pole... North Pole, Alaska that is. The small town of roughly 1,778 people advertises its ZIP code as the ZIP code of <a href= http://www.livescience.com/healthday/600271.html target=new>Santa</a>. The Holiday spirit is felt year-round as candy-cane striped street lights keep things moving along festive places such as St. Nicholas Drive, Snowman Lane and Kris Kringle Drive.
Christmas cards and Coke commercials can be blamed for the misconception that polar bears and <a href= http://www.livescience.com/penguins/ target=new>penguins</a> live in the same frigid neighborhood. If penguins of the Antarctic and Artic-dwelling <a href= http://www.livescience.com/animals/060612_polar_bears.html target=new>polar bears</a> ever did cross the same frozen paths, the waddling birds would make for very easy prey for the <a href= http://www.livescience.com/animals/top10_deadliestanimals.html target=new>giant bears</a>. But since penguins neednâ€™t worry about land predators, they have adapted their wings into paddle-like flippers to <a href= http://www.livescience.com/animals/061201_penguin_dive.html target=new>maneuver</a> through the ocean.
Energy-hungry nations are forging northward as an estimated one quarter of all <a href= http://www.livescience.com/environment/070324_ap_arctic_melt.html target=new>untapped oil reserves</a> lie north of the Arctic circle, according to the U.S. Geological Survey. Russia has taken the bold step of <a href= http://www.livescience.com/environment/070801_russia_npole.html target=new>laying claim</a> to a large swath of the Arctic region in hopes of exploring gas deposits in the Lomonosov Ridgeâ€”a 1,200-mile underwater mountain range purported to hold up to 10 billion tons of the <a href= http://www.livescience.com/environment/051011_oil_origins.html target=new>coveted resource</a>. Even the U.S. is getting involved, sending an <a href= http://www.livescience.com/environment/070811_ap_ice_breaker.html target=new>icebreaker ship</a> to map out their Arctic territory off Alaska. While it is believed by some that deposits of petroleum exist in the southern continental shelf, such as the area under the Ross Sea, the Antarctic Treaty makes oil drilling momentarily off-limits.
Despite symbolic images of past explorers triumphantly planting flags at the <a href= http://www.livescience.com/history/070122_ap_explore_antarctica.html target=new>South Pole</a>, the continent remains the only place on Earth not owned by anyone. It has no history of native peoples and is governed by the Antarctic treaty, which maintains that the land and resources be used for peaceful and <a href= http://www.livescience.com/php/multimedia/imagegallery/igviewer.php?imgid=460&gid=32&index=0 target=new>scientific purposes</a>. This is in stark contrast to the more than 4 million people living within the Arctic circle in several small towns as well as major cities such as Barrow, Alaska; Tromso, Norway; and Muramansk and Salekhaard in Russia.
The <a href= http://www.livescience.com/php/video/player.php?video_id=under_antarctic_quest target=new>southernmost continent</a> has roughly 90 percent of the worldâ€™s ice, which amounts to nearly three quarters of the Earthâ€™s fresh water being locked away there. This has led some to float the idea of towing <a href= http://www.livescience.com/php/multimedia/imagegallery/igviewer.php?imgid=247&gid=18 target=new>icebergs</a> to quench dry, drought-stricken areas. In fact, Prince Mohammed al Faisal of Saudi Arabia once considered a plan to find a 100 million-ton iceberg off <a href= http://www.livescience.com/antarctica/ target=new>Antarctica</a> and tow it to the Arabian peninsula.
The Arctic region is essentially a <a href= http://www.livescience.com/environment/050223_north_pole.html target=new>frozen ocean</a> surrounded by land. Conversely, <a href= http://www.livescience.com/php/video/player.php?video_id=eoe_quest target=new>Antarctica</a> is a continentâ€”with mountain ranges and lakesâ€”surrounded by an ocean. Socially and politically, though, the Arctic region includes the northern territories of Canada, <a href= http://www.livescience.com/imageoftheday/siod_070409.html target=new>Greenland</a> (a territory of Denmark), Russia, Iceland, Norway, Sweden, Finland and the United States.