[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:01.45,0:00:02.78,Default,,0000,0000,0000,,(soft ambient music)
Dialogue: 0,0:00:02.78,0:00:04.78,Default,,0000,0000,0000,,[Kristen] Why is the world warming up?
Dialogue: 0,0:00:06.82,0:00:09.63,Default,,0000,0000,0000,,Let's think of Earth for just\Na moment as a greenhouse.
Dialogue: 0,0:00:10.95,0:00:13.27,Default,,0000,0000,0000,,Every second, a huge amount of energy
Dialogue: 0,0:00:13.27,0:00:14.98,Default,,0000,0000,0000,,smashes into our greenhouse.
Dialogue: 0,0:00:16.96,0:00:20.49,Default,,0000,0000,0000,,Our atmosphere, the glass roof and walls,
Dialogue: 0,0:00:20.49,0:00:22.58,Default,,0000,0000,0000,,reflect some of that energy,
Dialogue: 0,0:00:22.58,0:00:25.58,Default,,0000,0000,0000,,but most of it passes right\Nthrough and heats everything up.
Dialogue: 0,0:00:27.34,0:00:29.88,Default,,0000,0000,0000,,Much of that heat used to\Nescape back into space,
Dialogue: 0,0:00:29.88,0:00:32.16,Default,,0000,0000,0000,,keeping us at a stable, warm temperature.
Dialogue: 0,0:00:33.67,0:00:35.02,Default,,0000,0000,0000,,But then something changed.
Dialogue: 0,0:00:36.11,0:00:38.65,Default,,0000,0000,0000,,Humans began to spew enough carbon dioxide
Dialogue: 0,0:00:38.65,0:00:41.00,Default,,0000,0000,0000,,to fill billions of greenhouses each day.
Dialogue: 0,0:00:42.90,0:00:45.54,Default,,0000,0000,0000,,What does all that greenhouse gas do?
Dialogue: 0,0:00:45.54,0:00:47.79,Default,,0000,0000,0000,,It makes the glass of\Nour greenhouse thicker.
Dialogue: 0,0:00:48.76,0:00:51.00,Default,,0000,0000,0000,,Thicker glass means\Nheat escapes into space
Dialogue: 0,0:00:51.00,0:00:52.44,Default,,0000,0000,0000,,much more slowly.
Dialogue: 0,0:00:52.44,0:00:54.24,Default,,0000,0000,0000,,And don't forget, energy from the sun
Dialogue: 0,0:00:54.24,0:00:57.27,Default,,0000,0000,0000,,is still streaming in\Njust as quickly as before.
Dialogue: 0,0:00:57.27,0:00:59.53,Default,,0000,0000,0000,,The result is a planet with temperatures
Dialogue: 0,0:00:59.53,0:01:04.24,Default,,0000,0000,0000,,too hot for our liking\Nand, eventually, living.