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  • On our planet,

  • we have two polar regions:

  • the Arctic, whose name comes from

  • the Greek Arktikos, of the North,

  • and the Antarctic

  • from Antarktikos,

  • opposite of the North.

  • But there's an easier way to remember them

  • if you just remember what surrounds them.

  • The Arctic, situated in the Northern hemisphere of our planet,

  • is an ocean entirely surrounded by land.

  • On the other side of the world,

  • the Antarctic is a continent

  • entirely surrounded by ocean.

  • So, the Arctic has polar bears but no penguins,

  • and the Antarctic has penguins but no polar bears.

  • Let's talk about the Arctic first.

  • The Arctic region consists of a vast, ice-covered ocean

  • surrounded by treeless permafrost.

  • The area can be defined

  • as the region between the Arctic Circle

  • and the North Pole.

  • If you were to stand at the North Pole,

  • everywhere you looked, in all directions,

  • would be south.

  • But standing at the North Pole

  • is difficult to do for very long

  • because it's in the middle of an ocean,

  • covered by constantly shifting, frozen sea ice.

  • If you were to fall into the water at the North Pole,

  • you'd fall into water that's 13,980 feet deep.

  • Above the water, average winter temperatures

  • can be as low as -40 degrees Celsius,

  • and the coldest recorded temperature

  • is approximately -68 degrees Celsius.

  • Despite these incredibly harsh conditions,

  • humans have populated areas in the Arctic

  • for thousands of years.

  • Life in the Arctic includes organisms living in the ice,

  • zooplankton and phytoplankton,

  • fish and marine mammals,

  • birds,

  • land animals,

  • plants,

  • and human societies.

  • Okay, what about Antarctica?

  • Antarctica is Earth's southernmost continent,

  • and it contains the geographic South Pole.

  • It's the fifth largest continent on the planet

  • at nearly twice the size of Australia.

  • Almost 98% of Anarctica is covered by ice

  • at least one mile in thickness.

  • Conditions in Antarctica are some of the most extreme

  • in the entire world.

  • On average, it's the coldest,

  • windiest,

  • driest continent

  • and has the highest average elevation

  • of all the continents.

  • You might think that it snows all the time at the Poles,

  • but Antarctica is so dry,

  • it's considered a desert

  • with annual precipitation

  • of only 200 millimeters along the coast

  • and far less inland.

  • The temperature in Antarctica

  • has reached -89 degrees Celsius.

  • Because it's so harsh and hard to get to,

  • there are no permanent human residents on Antarctica,

  • but anywhere from 1,000 to 5,000 people

  • reside throughout the year

  • at the research stations scattered across the continent.

  • Even the most extreme animals fight for survival,

  • and only cold-adapted organisms survive there,

  • including many types of algae,

  • animals,

  • bacteria,

  • fungi,

  • plants,

  • and protista.

  • But why is Antarctica colder than its northern cousin?

  • Well, first, much of the continent

  • is more than three kilometers above sea level,

  • and temperature decreases with elevation.

  • That's why mountaintops have snow on them.

  • Second, remember that the Arctic

  • is really a frozen ocean.

  • The water in the ocean beneath it

  • is warmer than the frozen ground in the Antarctic,

  • and that warmth is transferred through the ice pack.

  • This prevents temperatures in the Arctic regions

  • from reaching the extremes

  • typical of the land surface of Antarctica.

  • Third, the seasons are conspiring against the Antarctic.

  • During the aphelion in July,

  • when the Earth is the farthest away from the Sun,

  • it also happens to be winter in the Antarctic,

  • which creates a double-whammy of cold

  • for the southern pole.

  • But despite being inhospitable,

  • the North and South Pole are a big reason

  • why our planet is the way it is.

  • Both of our polar regions

  • are very important climate controllers.

  • They help moderate the temperature

  • in our temperate zones

  • and give us stable weather.

  • As sea ice in the Arctic declines

  • due to climate change and global warming,

  • weather around the globe

  • becomes increasing more unstable.

On our planet,

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B1 TED-Ed arctic antarctica antarctic pole continent

【TED-Ed】The Arctic vs. the Antarctic - Camille Seaman

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    VoiceTube posted on 2013/10/25
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