The Arctic vs. the Antarctic - Camille Seaman

4,611,322 views ・ 2013-08-19

TED-Ed


Please double-click on the English subtitles below to play the video.

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On our planet,
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we have two polar regions:
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the Arctic, whose name comes from
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the Greek Arktikos, of the North,
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and the Antarctic
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from Antarktikos,
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opposite of the North.
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But there's an easier way to remember them
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if you just remember what surrounds them.
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The Arctic, situated in the Northern hemisphere of our planet,
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is an ocean entirely surrounded by land.
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On the other side of the world,
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the Antarctic is a continent
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entirely surrounded by ocean.
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So, the Arctic has polar bears but no penguins,
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and the Antarctic has penguins but no polar bears.
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Let's talk about the Arctic first.
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The Arctic region consists of a vast, ice-covered ocean
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surrounded by treeless permafrost.
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The area can be defined
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as the region between the Arctic Circle
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and the North Pole.
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If you were to stand at the North Pole,
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everywhere you looked, in all directions,
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would be south.
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But standing at the North Pole
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is difficult to do for very long
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because it's in the middle of an ocean,
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covered by constantly shifting, frozen sea ice.
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If you were to fall into the water at the North Pole,
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you'd fall into water that's 13,980 feet deep.
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Above the water, average winter temperatures
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can be as low as -40 degrees Celsius,
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and the coldest recorded temperature
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is approximately -68 degrees Celsius.
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Despite these incredibly harsh conditions,
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humans have populated areas in the Arctic
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for thousands of years.
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Life in the Arctic includes organisms living in the ice,
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zooplankton and phytoplankton,
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fish and marine mammals,
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birds,
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land animals,
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plants,
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and human societies.
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Okay, what about Antarctica?
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Antarctica is Earth's southernmost continent,
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and it contains the geographic South Pole.
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It's the fifth largest continent on the planet
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at nearly twice the size of Australia.
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Almost 98% of Anarctica is covered by ice
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at least one mile in thickness.
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Conditions in Antarctica are some of the most extreme
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in the entire world.
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On average, it's the coldest,
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windiest,
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driest continent
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and has the highest average elevation
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of all the continents.
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You might think that it snows all the time at the Poles,
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but Antarctica is so dry,
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it's considered a desert
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with annual precipitation
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of only 200 millimeters along the coast
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and far less inland.
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The temperature in Antarctica
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has reached -89 degrees Celsius.
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Because it's so harsh and hard to get to,
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there are no permanent human residents on Antarctica,
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but anywhere from 1,000 to 5,000 people
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reside throughout the year
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at the research stations scattered across the continent.
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Even the most extreme animals fight for survival,
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and only cold-adapted organisms survive there,
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including many types of algae,
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animals,
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bacteria,
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fungi,
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plants,
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and protista.
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But why is Antarctica colder than its northern cousin?
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Well, first, much of the continent
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is more than three kilometers above sea level,
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and temperature decreases with elevation.
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That's why mountaintops have snow on them.
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Second, remember that the Arctic
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is really a frozen ocean.
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The water in the ocean beneath it
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is warmer than the frozen ground in the Antarctic,
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and that warmth is transferred through the ice pack.
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This prevents temperatures in the Arctic regions
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from reaching the extremes
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typical of the land surface of Antarctica.
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Third, the seasons are conspiring against the Antarctic.
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During the aphelion in July,
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when the Earth is the farthest away from the Sun,
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it also happens to be winter in the Antarctic,
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which creates a double-whammy of cold
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for the southern pole.
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But despite being inhospitable,
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the North and South Pole are a big reason
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why our planet is the way it is.
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Both of our polar regions
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are very important climate controllers.
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They help moderate the temperature
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in our temperate zones
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and give us stable weather.
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As sea ice in the Arctic declines
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due to climate change and global warming,
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weather around the globe
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becomes increasing more unstable.
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