[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:06.84,0:00:07.90,Default,,0000,0000,0000,,On our planet,
Dialogue: 0,0:00:07.90,0:00:09.61,Default,,0000,0000,0000,,we have two polar regions:
Dialogue: 0,0:00:09.61,0:00:11.37,Default,,0000,0000,0000,,the Arctic, whose name comes from
Dialogue: 0,0:00:11.37,0:00:13.49,Default,,0000,0000,0000,,the Greek Arktikos, of the North,
Dialogue: 0,0:00:13.49,0:00:14.80,Default,,0000,0000,0000,,and the Antarctic
Dialogue: 0,0:00:14.80,0:00:16.16,Default,,0000,0000,0000,,from Antarktikos,
Dialogue: 0,0:00:16.16,0:00:17.73,Default,,0000,0000,0000,,opposite of the North.
Dialogue: 0,0:00:17.73,0:00:19.98,Default,,0000,0000,0000,,But there's an easier way to remember them
Dialogue: 0,0:00:19.98,0:00:22.08,Default,,0000,0000,0000,,if you just remember what surrounds them.
Dialogue: 0,0:00:22.08,0:00:25.75,Default,,0000,0000,0000,,The Arctic, situated in the Northern hemisphere of our planet,
Dialogue: 0,0:00:25.75,0:00:29.00,Default,,0000,0000,0000,,is an ocean entirely surrounded by land.
Dialogue: 0,0:00:29.00,0:00:30.55,Default,,0000,0000,0000,,On the other side of the world,
Dialogue: 0,0:00:30.55,0:00:32.22,Default,,0000,0000,0000,,the Antarctic is a continent
Dialogue: 0,0:00:32.22,0:00:34.76,Default,,0000,0000,0000,,entirely surrounded by ocean.
Dialogue: 0,0:00:34.76,0:00:37.73,Default,,0000,0000,0000,,So, the Arctic has polar bears but no penguins,
Dialogue: 0,0:00:37.73,0:00:40.71,Default,,0000,0000,0000,,and the Antarctic has penguins but no polar bears.
Dialogue: 0,0:00:41.36,0:00:43.55,Default,,0000,0000,0000,,Let's talk about the Arctic first.
Dialogue: 0,0:00:43.55,0:00:47.02,Default,,0000,0000,0000,,The Arctic region consists of a vast, ice-covered ocean
Dialogue: 0,0:00:47.02,0:00:49.63,Default,,0000,0000,0000,,surrounded by treeless permafrost.
Dialogue: 0,0:00:49.63,0:00:51.19,Default,,0000,0000,0000,,The area can be defined
Dialogue: 0,0:00:51.19,0:00:53.13,Default,,0000,0000,0000,,as the region between the Arctic Circle
Dialogue: 0,0:00:53.13,0:00:54.59,Default,,0000,0000,0000,,and the North Pole.
Dialogue: 0,0:00:54.59,0:00:56.22,Default,,0000,0000,0000,,If you were to stand at the North Pole,
Dialogue: 0,0:00:56.22,0:00:58.84,Default,,0000,0000,0000,,everywhere you looked, in all directions,
Dialogue: 0,0:00:58.84,0:00:59.96,Default,,0000,0000,0000,,would be south.
Dialogue: 0,0:00:59.96,0:01:01.32,Default,,0000,0000,0000,,But standing at the North Pole
Dialogue: 0,0:01:01.32,0:01:03.26,Default,,0000,0000,0000,,is difficult to do for very long
Dialogue: 0,0:01:03.26,0:01:05.40,Default,,0000,0000,0000,,because it's in the middle of an ocean,
Dialogue: 0,0:01:05.40,0:01:08.42,Default,,0000,0000,0000,,covered by constantly shifting, frozen sea ice.
Dialogue: 0,0:01:08.42,0:01:11.17,Default,,0000,0000,0000,,If you were to fall into the water at the North Pole,
Dialogue: 0,0:01:11.17,0:01:15.63,Default,,0000,0000,0000,,you'd fall into water that's 13,980 feet deep.
Dialogue: 0,0:01:15.63,0:01:18.17,Default,,0000,0000,0000,,Above the water, average winter temperatures
Dialogue: 0,0:01:18.17,0:01:21.59,Default,,0000,0000,0000,,can be as low as -40 degrees Celsius,
Dialogue: 0,0:01:21.59,0:01:23.35,Default,,0000,0000,0000,,and the coldest recorded temperature
Dialogue: 0,0:01:23.35,0:01:27.93,Default,,0000,0000,0000,,is approximately -68 degrees Celsius.
Dialogue: 0,0:01:27.93,0:01:29.26,Default,,0000,0000,0000,,Despite these incredibly harsh conditions,
Dialogue: 0,0:01:29.26,0:01:31.58,Default,,0000,0000,0000,,humans have populated areas in the Arctic
Dialogue: 0,0:01:31.58,0:01:33.80,Default,,0000,0000,0000,,for thousands of years.
Dialogue: 0,0:01:33.80,0:01:37.48,Default,,0000,0000,0000,,Life in the Arctic includes organisms living in the ice,
Dialogue: 0,0:01:37.48,0:01:39.46,Default,,0000,0000,0000,,zooplankton and phytoplankton,
Dialogue: 0,0:01:39.46,0:01:41.04,Default,,0000,0000,0000,,fish and marine mammals,
Dialogue: 0,0:01:41.04,0:01:41.73,Default,,0000,0000,0000,,birds,
Dialogue: 0,0:01:41.73,0:01:42.37,Default,,0000,0000,0000,,land animals,
Dialogue: 0,0:01:42.37,0:01:42.98,Default,,0000,0000,0000,,plants,
Dialogue: 0,0:01:42.98,0:01:45.08,Default,,0000,0000,0000,,and human societies.
Dialogue: 0,0:01:45.08,0:01:47.18,Default,,0000,0000,0000,,Okay, what about Antarctica?
Dialogue: 0,0:01:47.18,0:01:50.22,Default,,0000,0000,0000,,Antarctica is Earth's southernmost continent,
Dialogue: 0,0:01:50.22,0:01:52.88,Default,,0000,0000,0000,,and it contains the geographic South Pole.
Dialogue: 0,0:01:52.88,0:01:55.59,Default,,0000,0000,0000,,It's the fifth largest continent on the planet
Dialogue: 0,0:01:55.59,0:01:57.84,Default,,0000,0000,0000,,at nearly twice the size of Australia.
Dialogue: 0,0:01:57.84,0:02:01.34,Default,,0000,0000,0000,,Almost 98% of Anarctica is covered by ice
Dialogue: 0,0:02:01.34,0:02:03.78,Default,,0000,0000,0000,,at least one mile in thickness.
Dialogue: 0,0:02:03.78,0:02:06.86,Default,,0000,0000,0000,,Conditions in Antarctica are some of the most extreme
Dialogue: 0,0:02:06.86,0:02:08.30,Default,,0000,0000,0000,,in the entire world.
Dialogue: 0,0:02:08.30,0:02:10.16,Default,,0000,0000,0000,,On average, it's the coldest,
Dialogue: 0,0:02:10.16,0:02:10.97,Default,,0000,0000,0000,,windiest,
Dialogue: 0,0:02:10.97,0:02:12.35,Default,,0000,0000,0000,,driest continent
Dialogue: 0,0:02:12.35,0:02:14.18,Default,,0000,0000,0000,,and has the highest average elevation
Dialogue: 0,0:02:14.18,0:02:15.72,Default,,0000,0000,0000,,of all the continents.
Dialogue: 0,0:02:15.72,0:02:18.69,Default,,0000,0000,0000,,You might think that it snows all the time at the Poles,
Dialogue: 0,0:02:18.69,0:02:20.53,Default,,0000,0000,0000,,but Antarctica is so dry,
Dialogue: 0,0:02:20.53,0:02:21.100,Default,,0000,0000,0000,,it's considered a desert
Dialogue: 0,0:02:21.100,0:02:23.11,Default,,0000,0000,0000,,with annual precipitation
Dialogue: 0,0:02:23.11,0:02:26.25,Default,,0000,0000,0000,,of only 200 millimeters along the coast
Dialogue: 0,0:02:26.25,0:02:27.61,Default,,0000,0000,0000,,and far less inland.
Dialogue: 0,0:02:27.61,0:02:29.16,Default,,0000,0000,0000,,The temperature in Antarctica
Dialogue: 0,0:02:29.16,0:02:32.56,Default,,0000,0000,0000,,has reached -89 degrees Celsius.
Dialogue: 0,0:02:32.56,0:02:34.100,Default,,0000,0000,0000,,Because it's so harsh and hard to get to,
Dialogue: 0,0:02:34.100,0:02:37.97,Default,,0000,0000,0000,,there are no permanent human residents on Antarctica,
Dialogue: 0,0:02:37.97,0:02:40.50,Default,,0000,0000,0000,,but anywhere from 1,000 to 5,000 people
Dialogue: 0,0:02:40.50,0:02:41.75,Default,,0000,0000,0000,,reside throughout the year
Dialogue: 0,0:02:41.75,0:02:44.92,Default,,0000,0000,0000,,at the research stations scattered across the continent.
Dialogue: 0,0:02:44.92,0:02:48.30,Default,,0000,0000,0000,,Even the most extreme animals fight for survival,
Dialogue: 0,0:02:48.30,0:02:51.10,Default,,0000,0000,0000,,and only cold-adapted organisms survive there,
Dialogue: 0,0:02:51.10,0:02:53.09,Default,,0000,0000,0000,,including many types of algae,
Dialogue: 0,0:02:53.09,0:02:54.24,Default,,0000,0000,0000,,animals,
Dialogue: 0,0:02:54.24,0:02:55.33,Default,,0000,0000,0000,,bacteria,
Dialogue: 0,0:02:55.33,0:02:56.29,Default,,0000,0000,0000,,fungi,
Dialogue: 0,0:02:56.29,0:02:57.11,Default,,0000,0000,0000,,plants,
Dialogue: 0,0:02:57.11,0:02:58.08,Default,,0000,0000,0000,,and protista.
Dialogue: 0,0:02:59.51,0:03:02.85,Default,,0000,0000,0000,,But why is Antarctica colder than its northern cousin?
Dialogue: 0,0:03:02.85,0:03:04.47,Default,,0000,0000,0000,,Well, first, much of the continent
Dialogue: 0,0:03:04.47,0:03:07.08,Default,,0000,0000,0000,,is more than three kilometers above sea level,
Dialogue: 0,0:03:07.08,0:03:09.43,Default,,0000,0000,0000,,and temperature decreases with elevation.
Dialogue: 0,0:03:09.43,0:03:12.06,Default,,0000,0000,0000,,That's why mountaintops have snow on them.
Dialogue: 0,0:03:12.06,0:03:13.85,Default,,0000,0000,0000,,Second, remember that the Arctic
Dialogue: 0,0:03:13.85,0:03:16.31,Default,,0000,0000,0000,,is really a frozen ocean.
Dialogue: 0,0:03:16.31,0:03:17.85,Default,,0000,0000,0000,,The water in the ocean beneath it
Dialogue: 0,0:03:17.85,0:03:20.82,Default,,0000,0000,0000,,is warmer than the frozen ground in the Antarctic,
Dialogue: 0,0:03:20.82,0:03:23.66,Default,,0000,0000,0000,,and that warmth is transferred through the ice pack.
Dialogue: 0,0:03:23.66,0:03:26.07,Default,,0000,0000,0000,,This prevents temperatures in the Arctic regions
Dialogue: 0,0:03:26.07,0:03:27.49,Default,,0000,0000,0000,,from reaching the extremes
Dialogue: 0,0:03:27.49,0:03:30.69,Default,,0000,0000,0000,,typical of the land surface of Antarctica.
Dialogue: 0,0:03:30.69,0:03:34.57,Default,,0000,0000,0000,,Third, the seasons are conspiring against the Antarctic.
Dialogue: 0,0:03:34.57,0:03:36.62,Default,,0000,0000,0000,,During the aphelion in July,
Dialogue: 0,0:03:36.62,0:03:38.74,Default,,0000,0000,0000,,when the Earth is the farthest away from the Sun,
Dialogue: 0,0:03:38.74,0:03:41.55,Default,,0000,0000,0000,,it also happens to be winter in the Antarctic,
Dialogue: 0,0:03:41.55,0:03:43.45,Default,,0000,0000,0000,,which creates a double-whammy of cold
Dialogue: 0,0:03:43.45,0:03:44.75,Default,,0000,0000,0000,,for the southern pole.
Dialogue: 0,0:03:44.75,0:03:46.91,Default,,0000,0000,0000,,But despite being inhospitable,
Dialogue: 0,0:03:46.91,0:03:49.33,Default,,0000,0000,0000,,the North and South Pole are a big reason
Dialogue: 0,0:03:49.33,0:03:51.43,Default,,0000,0000,0000,,why our planet is the way it is.
Dialogue: 0,0:03:51.43,0:03:52.94,Default,,0000,0000,0000,,Both of our polar regions
Dialogue: 0,0:03:52.94,0:03:55.16,Default,,0000,0000,0000,,are very important climate controllers.
Dialogue: 0,0:03:55.16,0:03:56.89,Default,,0000,0000,0000,,They help moderate the temperature
Dialogue: 0,0:03:56.89,0:03:58.65,Default,,0000,0000,0000,,in our temperate zones
Dialogue: 0,0:03:58.65,0:04:00.35,Default,,0000,0000,0000,,and give us stable weather.
Dialogue: 0,0:04:00.35,0:04:02.48,Default,,0000,0000,0000,,As sea ice in the Arctic declines
Dialogue: 0,0:04:02.48,0:04:04.56,Default,,0000,0000,0000,,due to climate change and global warming,
Dialogue: 0,0:04:04.56,0:04:05.91,Default,,0000,0000,0000,,weather around the globe
Dialogue: 0,0:04:05.91,0:04:08.23,Default,,0000,0000,0000,,becomes increasing more unstable.