Earth's Polar Regions

Do you wonder what Earth's Polar Regions are like? Where do polar bears live? Where do penguins swim? Why does the Sun never shine in winter in the Arctic? Why does aurora occur near the Earth’s Poles? How big are the Earth’s ice caps, and are they changing? The Earth’s Polar Regions are hosts to unique phenomena and ecosystems – both fascinating and beautiful. Explore the Earth’s Arctic and Antarctic through the links in this section.
A group of
  Emperor penguins wait their turn to dive into the ocean near <a
  Island, Antarctica</a>
  on November 3, 2004.
Emperor penguins routinely dive to 500 meters in
  search of food. Scientists are interested in understanding how they can
  endure the stress of these dives in such an <a
  environment</a>.<p><small><em> Image courtesy of Emily Stone,   National Science Foundation</em></small></p>Roaming across Arctic <a
  href="/earth/polar/sea_ice.html&edu=high&dev=1">sea ice</a>, <a
  bears</a> peer through cracks in the ice to look for ringed seals, their
  favorite food, in the water below. Almost all of a polar bear's food comes
  from the sea. The <a
  href="/earth/polar/sea_ice.html&edu=high&dev=1">floating sea
  ice</a> is a perfect vantage point for the bears as they hunt for food.
  Unfortunately, the amount of sea ice floating in the <a
  region</a> is shrinking each year, and getting farther apart.<p><small><em>Image courtesy of Ansgar Walk.  Creative Commons Attribution-Share Alike 2.5 Generic license.</em></small></p><a href="/earth/polar/inuit_culture.html&edu=high&dev=1">The
  Inuit</a> are the native cultures that continue to live on coastal areas of <a
  tundra</a> in Canada, Alaska (USA), Siberia (Russia), and Greenland. This
  picture shows several Inuit constructing an igloo with blocks of <a
  in November, 1924. Traditionally, Inuit lived in igloos during the coldest
  months and tent-like huts during the warmer months.<p><small><em>   Library of Congress Prints and Photographs, Photograph by Frank E. Kleinschmidt</em></small></p>Did you know that the Earth's <a
  North pole</a> is not in the same place as the Earth's <a
  magnetic pole</a>? They are actually several hundred kilometers apart,
  making navigation with a compass impossible near the poles. This picture
  illustrates where they were in 2005. Right at the geographic poles, the <a
  href="/sun/sun.html&edu=high&dev=1">Sun</a> shines for half
  the year and it is dark for the other half of the year. This makes a year
  like one long day.<p><small><em>Image courtesy of Windows to the Universe</em></small></p>Icebergs floating near Cape York, Greenland
  in September 2005. Icebergs are large pieces of ice floating in
  the <a href="/earth/Water/ocean.html&edu=high&dev=1">ocean</a>
  that have broken off of <a
  shelves or glaciers</a> in <a
  href="/earth/polar/polar.html&edu=high&dev=1">Earth's polar
  regions</a>. They are a part of the <a
  Approximately 90% of an iceberg's <a
  href="/glossary/mass.html&edu=high&dev=1">mass</a> is below
  the surface of the seawater. Because ice is less dense than water, a small
  portion of the iceberg stays above the seawater.<p><small><em>Image courtesy of   Mila Zinkova, Creative Commons Attribution ShareAlike license</em></small></p>Greenland's <a href="">ice sheet</a> saw a record <a href="">melt</a> in July 2012.  Scientists studying this event have found that this melting event was triggered by an influx of unusually warm air and amplified by the presence of a blanket of thin low-level <a href="">clouds</a> which pushed temperatures up above freezing.  For more information see the <a href="">press release</a> from the University of Wisconsin Madison.<p><small><em>Image courtesy of University of Wisconsin-Madison</em></small></p>

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