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1 00:00:01,394 00:00:05,872 ? ?
2 00:00:05,881 00:00:08,839 Narrator: Ever since humanity went into space, Narrator: Ever since humanity went into space,
3 00:00:08,914 00:00:12,359 We've looked down on the marvels of our civilization. We've looked down on the marvels of our civilization.
4 00:00:16,121 00:00:20,199 We've achieved incredible things, We've achieved incredible things,
5 00:00:20,274 00:00:25,072 But we didn't do this alone. But we didn't do this alone.
6 00:00:25,081 00:00:29,152 Thanks to space technology, we are gaining new insight Thanks to space technology, we are gaining new insight
7 00:00:29,161 00:00:32,352 Into how the dynamic life of our planet Into how the dynamic life of our planet
8 00:00:32,361 00:00:36,912 Has influenced the rise of our species. Has influenced the rise of our species.
9 00:00:36,921 00:00:41,072 ? ?
10 00:00:41,081 00:00:44,159 We're finding evidence that our exceptional brains We're finding evidence that our exceptional brains
11 00:00:44,201 00:00:49,632 May be an evolutionary response to an unpredictable climate. May be an evolutionary response to an unpredictable climate.
12 00:00:49,641 00:00:53,072 Man: When you really look at what our brains do, Man: When you really look at what our brains do,
13 00:00:53,081 00:00:56,519 They're our organ of adaptability. They're our organ of adaptability.
14 00:00:56,594 00:00:59,559 Narrator: We're revealing how a lifestyle revolution Narrator: We're revealing how a lifestyle revolution
15 00:00:59,634 00:01:03,399 Triggered the growth of civilization. Triggered the growth of civilization.
16 00:01:03,474 00:01:06,919 Man: These are probably the earliest ancient roadways Man: These are probably the earliest ancient roadways
17 00:01:06,994 00:01:09,199 In the world. In the world.
18 00:01:09,241 00:01:12,839 Narrator: And we're uncovering the full power and peril Narrator: And we're uncovering the full power and peril
19 00:01:12,914 00:01:16,439 Of unleashing the energy stored within our planet Of unleashing the energy stored within our planet
20 00:01:16,514 00:01:19,872 Hundreds of millions of years ago. Hundreds of millions of years ago.
21 00:01:19,881 00:01:21,639 Man: That's an energy revolution, Man: That's an energy revolution,
22 00:01:21,714 00:01:26,199 And there are climatic and ecosystem consequences to that And there are climatic and ecosystem consequences to that
23 00:01:26,274 00:01:32,432 That are going to be present for thousands of years to come. That are going to be present for thousands of years to come.
24 00:01:32,441 00:01:35,632 Narrator: Humanity's very success is pushing us Narrator: Humanity's very success is pushing us
25 00:01:35,641 00:01:38,992 And our environment to the edge. And our environment to the edge.
26 00:01:39,001 00:01:42,839 Man: We have become a force to match anything that you see Man: We have become a force to match anything that you see
27 00:01:42,914 00:01:46,119 In a billion years of earth history. In a billion years of earth history.
28 00:01:46,194 00:01:49,199 Narrator: But our technology gives us a chance Narrator: But our technology gives us a chance
29 00:01:49,241 00:01:52,512 To shape what happens next. To shape what happens next.
30 00:01:52,521 00:01:56,032 Man: We can actually conceive of a desirable future Man: We can actually conceive of a desirable future
31 00:01:56,041 00:01:58,439 And build a global plan to get to that future. And build a global plan to get to that future.
32 00:01:58,514 00:02:02,592 That's the challenge for humanity in the 21st century. That's the challenge for humanity in the 21st century.
33 00:02:02,601 00:02:13,312 ? ?
34 00:02:13,321 00:02:16,119 Narrator: This is the story of us, Narrator: This is the story of us,
35 00:02:16,194 00:02:20,992 Of the life of earth in the age of humans. Of the life of earth in the age of humans.
36 00:02:21,001 00:02:30,999 ? ?
37 00:02:31,001 00:02:36,752 ? ?
38 00:02:36,761 00:02:40,592 From its birth 4.5 billion years ago, From its birth 4.5 billion years ago,
39 00:02:40,601 00:02:45,639 Planet earth has endured constant change-- Planet earth has endured constant change--
40 00:02:45,714 00:02:51,312 Devastating impacts from asteroids and comets, Devastating impacts from asteroids and comets,
41 00:02:51,321 00:02:53,399 And tectonic shifts generated And tectonic shifts generated
42 00:02:53,474 00:02:56,912 By the churning heat beneath its crust, By the churning heat beneath its crust,
43 00:02:56,921 00:03:00,832 Transforming the planet's environment. Transforming the planet's environment.
44 00:03:00,841 00:03:03,239 All life that clings to its surface All life that clings to its surface
45 00:03:03,314 00:03:07,199 Evolves to survive Evolves to survive
46 00:03:07,241 00:03:09,639 Or succumbs to extinction. Or succumbs to extinction.
47 00:03:13,081 00:03:16,959 Our story begins 300,000 years ago. Our story begins 300,000 years ago.
48 00:03:19,314 00:03:22,112 Earth's climate is colder than today, Earth's climate is colder than today,
49 00:03:22,121 00:03:28,079 With ice sheets extending from both poles. With ice sheets extending from both poles.
50 00:03:28,121 00:03:32,272 In the warmer equatorial zone on the african continent, In the warmer equatorial zone on the african continent,
51 00:03:32,281 00:03:37,159 A new creature arises, A new creature arises,
52 00:03:37,234 00:03:41,319 A species of ape with great potential. A species of ape with great potential.
53 00:03:41,394 00:03:44,119 They are us... They are us...
54 00:03:48,161 00:03:49,879 Homo sapiens. Homo sapiens.
55 00:03:54,034 00:03:56,599 But 300,000 years ago, But 300,000 years ago,
56 00:03:56,674 00:03:58,999 We were not the only two-legged ape We were not the only two-legged ape
57 00:03:59,074 00:04:02,079 Wandering the african plains. Wandering the african plains.
58 00:04:04,514 00:04:07,639 2015, southern africa. 2015, southern africa.
59 00:04:10,194 00:04:13,559 In a region rich in ancient human fossils, In a region rich in ancient human fossils,
60 00:04:13,634 00:04:19,759 A fantastic new discovery awaits deep underground. A fantastic new discovery awaits deep underground.
61 00:04:21,474 00:04:22,679 It's the first time It's the first time
62 00:04:22,754 00:04:25,639 Paleoanthropologist dr. Lee berger Paleoanthropologist dr. Lee berger
63 00:04:25,714 00:04:31,312 Has explored the rising star cave system. Has explored the rising star cave system.
64 00:04:31,321 00:04:32,999 Lee berger: I had this map I'd created Lee berger: I had this map I'd created
65 00:04:33,074 00:04:34,999 Of almost 800 cave sites Of almost 800 cave sites
66 00:04:35,074 00:04:37,072 That were all entryways into the underworld That were all entryways into the underworld
67 00:04:37,081 00:04:40,599 That I hadn't been in yet, and that was the mission. That I hadn't been in yet, and that was the mission.
68 00:04:42,114 00:04:45,072 Narrator: Berger has heard rumors of human remains Narrator: Berger has heard rumors of human remains
69 00:04:45,081 00:04:47,759 Glimpsed down one of these passageways. Glimpsed down one of these passageways.
70 00:04:51,154 00:04:56,199 It's challenging terrain for the scientific team. It's challenging terrain for the scientific team.
71 00:04:56,274 00:04:57,472 Berger: To travel just 100 meters Berger: To travel just 100 meters
72 00:04:57,481 00:04:59,712 Takes 20, 30, 40 minutes, Takes 20, 30, 40 minutes,
73 00:04:59,721 00:05:01,712 Depending on how fit you are and how good you are Depending on how fit you are and how good you are
74 00:05:01,721 00:05:04,512 At squeezing through very tight spaces. At squeezing through very tight spaces.
75 00:05:04,521 00:05:06,992 It's a torturous journey. It's a torturous journey.
76 00:05:07,001 00:05:13,072 ? ?
77 00:05:13,081 00:05:17,319 Narrator: The effort is worth it. Narrator: The effort is worth it.
78 00:05:17,394 00:05:20,832 They make an incredible find. They make an incredible find.
79 00:05:20,841 00:05:21,639 Berger: I was speechless. Berger: I was speechless.
80 00:05:21,714 00:05:23,392 I mean, there I saw something I mean, there I saw something
81 00:05:23,401 00:05:26,352 I thought I would never see in my entire career. I thought I would never see in my entire career.
82 00:05:26,361 00:05:28,832 There was a clearly primitive hominid There was a clearly primitive hominid
83 00:05:28,841 00:05:31,319 Just lying there on the surface in the dirt. Just lying there on the surface in the dirt.
84 00:05:31,394 00:05:37,232 ? ?
85 00:05:37,241 00:05:41,072 Narrator: The body is just the beginning. Narrator: The body is just the beginning.
86 00:05:41,081 00:05:43,072 Berger and his team uncover bones Berger and his team uncover bones
87 00:05:43,081 00:05:46,032 From 15 separate skeletons, From 15 separate skeletons,
88 00:05:46,041 00:05:50,999 Dating from the time humans first spread across africa. Dating from the time humans first spread across africa.
89 00:05:51,074 00:05:54,839 Berger: We've had everything from individuals just born, Berger: We've had everything from individuals just born,
90 00:05:54,914 00:05:56,999 All the way to the extreme elderly, All the way to the extreme elderly,
91 00:05:57,074 00:06:00,359 And everybody in between. And everybody in between.
92 00:06:00,434 00:06:03,239 Narrator: But the bones are not human. Narrator: But the bones are not human.
93 00:06:05,881 00:06:10,752 They belong to a totally new species-- They belong to a totally new species--
94 00:06:10,761 00:06:12,439 Homo naledi. Homo naledi.
95 00:06:15,074 00:06:17,399 Berger: Imagine if you're standing out here Berger: Imagine if you're standing out here
96 00:06:17,474 00:06:21,239 300,000 years ago. 300,000 years ago.
97 00:06:21,314 00:06:24,319 A group of homo naledis from 500 meters... A group of homo naledis from 500 meters...
98 00:06:26,834 00:06:28,359 They'd look very little different from humans They'd look very little different from humans
99 00:06:28,434 00:06:32,279 Because they're walking on two legs. Because they're walking on two legs.
100 00:06:32,354 00:06:33,959 As they approach, As they approach,
101 00:06:34,034 00:06:36,439 You're going to start seeing things that are different. You're going to start seeing things that are different.
102 00:06:36,514 00:06:38,519 You're going to notice that the proportions aren't right, You're going to notice that the proportions aren't right,
103 00:06:38,594 00:06:42,192 That the heads are small, that the shoulders are narrow. That the heads are small, that the shoulders are narrow.
104 00:06:42,201 00:06:45,799 When they got about 50 meters from you, When they got about 50 meters from you,
105 00:06:45,874 00:06:48,199 You'd realize that's not a human coming at you. You'd realize that's not a human coming at you.
106 00:06:48,274 00:06:52,359 There'd be no mistaking. There'd be no mistaking.
107 00:06:52,434 00:06:54,032 Narrator: Naledi now joined the ranks Narrator: Naledi now joined the ranks
108 00:06:54,041 00:06:57,472 Of at least three other human-like species Of at least three other human-like species
109 00:06:57,481 00:07:00,679 That existed in parallel to homo sapiens That existed in parallel to homo sapiens
110 00:07:00,754 00:07:03,472 300,000 years ago, 300,000 years ago,
111 00:07:03,481 00:07:08,919 Exhibited here in the national museum of natural history. Exhibited here in the national museum of natural history.
112 00:07:08,994 00:07:11,392 Rick potts: We used to see human evolutionary history Rick potts: We used to see human evolutionary history
113 00:07:11,401 00:07:16,159 As that March of progress from ape-like to human beings. As that March of progress from ape-like to human beings.
114 00:07:16,201 00:07:20,359 Instead, what we've learned is that there were contemporaries. Instead, what we've learned is that there were contemporaries.
115 00:07:20,434 00:07:24,272 Our evolutionary tree is branching and diverse, Our evolutionary tree is branching and diverse,
116 00:07:24,281 00:07:25,632 Like the evolutionary trees Like the evolutionary trees
117 00:07:25,641 00:07:29,559 Of almost all other organisms on earth. Of almost all other organisms on earth.
118 00:07:29,634 00:07:32,079 Narrator: But if all these human-like competitors Narrator: But if all these human-like competitors
119 00:07:32,121 00:07:34,159 Once shared our planet, Once shared our planet,
120 00:07:34,201 00:07:37,552 Why are we the only ones left? Why are we the only ones left?
121 00:07:37,561 00:07:40,039 Potts: None of them now exist on earth. Potts: None of them now exist on earth.
122 00:07:40,201 00:07:42,599 We are the last bipeds standing. We are the last bipeds standing.
123 00:07:44,914 00:07:47,952 Narrator: Humanity's survival advantage may have its roots Narrator: Humanity's survival advantage may have its roots
124 00:07:47,961 00:07:52,039 In dramatic changes in the earth's unstable climate. In dramatic changes in the earth's unstable climate.
125 00:07:52,201 00:07:59,559 ? ?
126 00:07:59,634 00:08:02,999 Satellite images of the western sahara Satellite images of the western sahara
127 00:08:03,074 00:08:08,439 Reveal remains of a major river system 250 miles long... Reveal remains of a major river system 250 miles long...
128 00:08:10,521 00:08:15,479 Evidence that this was once a lush valley. Evidence that this was once a lush valley.
129 00:08:15,554 00:08:18,592 It's now believed that every 20,000 years It's now believed that every 20,000 years
130 00:08:18,601 00:08:20,592 Throughout humanity's evolution, Throughout humanity's evolution,
131 00:08:20,601 00:08:24,039 Periodic ice ages swing the african environment Periodic ice ages swing the african environment
132 00:08:24,114 00:08:28,512 From wet to dry and back again. From wet to dry and back again.
133 00:08:28,521 00:08:29,959 Potts: The past six million years Potts: The past six million years
134 00:08:30,034 00:08:32,032 Have been the most dramatic period Have been the most dramatic period
135 00:08:32,041 00:08:35,232 Of climate oscillation and change in landscapes Of climate oscillation and change in landscapes
136 00:08:35,241 00:08:37,879 Ever since the extinction of the dinosaurs Ever since the extinction of the dinosaurs
137 00:08:37,954 00:08:40,199 65 million years ago. 65 million years ago.
138 00:08:42,361 00:08:44,199 Narrator: Any species that can't cope Narrator: Any species that can't cope
139 00:08:44,274 00:08:48,832 With rapid environmental change will not endure. With rapid environmental change will not endure.
140 00:08:48,841 00:08:53,472 Potts: The boundary between survival and extinction Potts: The boundary between survival and extinction
141 00:08:53,481 00:08:54,999 Was really adaptability, Was really adaptability,
142 00:08:55,074 00:08:59,439 The ability to adjust to changes in the landscape. The ability to adjust to changes in the landscape.
143 00:09:01,721 00:09:03,392 Narrator: Scientists think the need Narrator: Scientists think the need
144 00:09:03,401 00:09:06,039 To solve environmental challenges To solve environmental challenges
145 00:09:06,114 00:09:11,119 Spurred homo sapiens to evolve a uniquely adaptive brain. Spurred homo sapiens to evolve a uniquely adaptive brain.
146 00:09:13,474 00:09:16,432 We developed imagination and language skills We developed imagination and language skills
147 00:09:16,441 00:09:18,679 Our rivals lacked. Our rivals lacked.
148 00:09:21,081 00:09:24,272 Potts: When you really look at what our brains do, Potts: When you really look at what our brains do,
149 00:09:24,281 00:09:27,072 They're our organ of adaptability. They're our organ of adaptability.
150 00:09:27,081 00:09:29,472 With language, we have the ability With language, we have the ability
151 00:09:29,481 00:09:34,039 Of not just having our brains being inside our skulls, Of not just having our brains being inside our skulls,
152 00:09:34,114 00:09:38,279 We have the possibility of our brains being shared with others We have the possibility of our brains being shared with others
153 00:09:38,354 00:09:40,519 In ways that go far beyond In ways that go far beyond
154 00:09:40,594 00:09:42,839 What any other organism was capable of doing What any other organism was capable of doing
155 00:09:42,914 00:09:45,879 Up to that time, including earlier humans, Up to that time, including earlier humans,
156 00:09:45,954 00:09:50,039 And that capacity to socially network our brains And that capacity to socially network our brains
157 00:09:50,121 00:09:54,992 Meant that innovations could start to not only be invented Meant that innovations could start to not only be invented
158 00:09:55,001 00:09:57,879 But also to accumulate. But also to accumulate.
159 00:09:57,954 00:10:00,279 That was our real card That was our real card
160 00:10:00,354 00:10:03,472 That we could put down on the survival table. That we could put down on the survival table.
161 00:10:03,481 00:10:07,239 ? ?
162 00:10:07,314 00:10:10,999 Narrator: Over 200,000 years of intense competition Narrator: Over 200,000 years of intense competition
163 00:10:11,074 00:10:12,992 In a fluctuating climate, In a fluctuating climate,
164 00:10:13,001 00:10:17,959 We become the only homo species still surviving in africa. We become the only homo species still surviving in africa.
165 00:10:20,674 00:10:23,952 Homo naledi and our other african rivals Homo naledi and our other african rivals
166 00:10:23,961 00:10:25,599 Are overwhelmed. Are overwhelmed.
167 00:10:28,114 00:10:32,959 And it's time for our mental advantage to go global. And it's time for our mental advantage to go global.
168 00:10:36,281 00:10:39,072 An extreme ice age causes sea levels An extreme ice age causes sea levels
169 00:10:39,081 00:10:42,439 To drop nearly 250 feet. To drop nearly 250 feet.
170 00:10:43,961 00:10:48,592 Sections of the red sea narrow to just a few miles wide. Sections of the red sea narrow to just a few miles wide.
171 00:10:48,601 00:10:54,512 ? ?
172 00:10:54,521 00:10:58,119 It's a new route out of africa It's a new route out of africa
173 00:10:58,194 00:11:00,999 That some of our ancestors now use That some of our ancestors now use
174 00:11:01,074 00:11:03,439 To spread across the world. To spread across the world.
175 00:11:07,241 00:11:08,832 The decline and disappearance The decline and disappearance
176 00:11:08,841 00:11:12,039 Of all remaining rival homo species Of all remaining rival homo species
177 00:11:12,114 00:11:15,239 Can be traced to this great migration. Can be traced to this great migration.
178 00:11:18,121 00:11:22,839 And our rivals are not the only casualties. And our rivals are not the only casualties.
179 00:11:22,914 00:11:25,872 We now begin to have an impact on the planet We now begin to have an impact on the planet
180 00:11:25,881 00:11:30,279 Unlike any other animal before or since. Unlike any other animal before or since.
181 00:11:38,114 00:11:41,919 The latest ice age approaches its peak. The latest ice age approaches its peak.
182 00:11:47,154 00:11:49,479 Over the last 30,000 years, Over the last 30,000 years,
183 00:11:49,554 00:11:56,192 Our ancestors have spread across the globe. Our ancestors have spread across the globe.
184 00:11:56,201 00:12:00,192 But their path to the americas was hindered. But their path to the americas was hindered.
185 00:12:00,201 00:12:05,952 Deep oceans proved a formidable obstruction, Deep oceans proved a formidable obstruction,
186 00:12:05,961 00:12:09,319 But now this barrier disappears. But now this barrier disappears.
187 00:12:09,394 00:12:12,119 Expanding ice caps cause sea levels Expanding ice caps cause sea levels
188 00:12:12,194 00:12:15,799 To dip to record lows. To dip to record lows.
189 00:12:15,874 00:12:21,312 In 2014, a satellite survey between siberia and alaska In 2014, a satellite survey between siberia and alaska
190 00:12:21,321 00:12:25,319 Measures the shallow contours of the seabed. Measures the shallow contours of the seabed.
191 00:12:25,394 00:12:29,399 Here is conclusive proof that 25,000 years ago, Here is conclusive proof that 25,000 years ago,
192 00:12:29,474 00:12:33,479 A 600-mile land corridor opens up. A 600-mile land corridor opens up.
193 00:12:33,554 00:12:38,592 ? ?
194 00:12:38,601 00:12:43,479 Across it, animals and humans start to migrate. Across it, animals and humans start to migrate.
195 00:12:46,834 00:12:53,472 But evidence from this late migration tells a bigger story-- But evidence from this late migration tells a bigger story--
196 00:12:53,481 00:12:55,479 That humans have by now amassed That humans have by now amassed
197 00:12:55,554 00:13:00,359 The power to unbalance an entire ecosystem. The power to unbalance an entire ecosystem.
198 00:13:00,434 00:13:06,919 ? ?
199 00:13:06,994 00:13:10,439 In michigan, a team of paleontologists investigates In michigan, a team of paleontologists investigates
200 00:13:10,514 00:13:13,072 The remains of an ice age lake. The remains of an ice age lake.
201 00:13:13,161 00:13:16,999 ? ?
202 00:13:17,074 00:13:21,559 Team leader dr. Dan fisher unearths incredible evidence Team leader dr. Dan fisher unearths incredible evidence
203 00:13:21,634 00:13:25,519 Of the deadly impact of this human migration. Of the deadly impact of this human migration.
204 00:13:28,754 00:13:30,119 Dan fisher: What's that? Dan fisher: What's that?
205 00:13:30,194 00:13:31,879 There's something there. There's something there.
206 00:13:31,954 00:13:34,272 Okay, this shape right here Okay, this shape right here
207 00:13:34,281 00:13:37,959 Is the central column-like section of a vertebra, Is the central column-like section of a vertebra,
208 00:13:38,034 00:13:40,592 The part that supports weight. The part that supports weight.
209 00:13:40,601 00:13:44,192 Oh! There's another one below this. Oh! There's another one below this.
210 00:13:44,201 00:13:48,239 Narrator: These are the remains of an icon of the ice age... Narrator: These are the remains of an icon of the ice age...
211 00:13:50,834 00:13:52,759 The woolly mammoth. The woolly mammoth.
212 00:13:52,834 00:13:54,759 Fisher: Humans living here at this time Fisher: Humans living here at this time
213 00:13:54,834 00:13:56,199 Would absolutely have encountered them Would absolutely have encountered them
214 00:13:56,274 00:14:00,432 On a more or less daily basis. On a more or less daily basis.
215 00:14:00,441 00:14:02,039 Narrator: Before humans arrived, Narrator: Before humans arrived,
216 00:14:02,114 00:14:06,039 Mammoths and other large animals roamed throughout the americas. Mammoths and other large animals roamed throughout the americas.
217 00:14:08,674 00:14:12,719 But they had never faced a predator this cunning. But they had never faced a predator this cunning.
218 00:14:16,274 00:14:17,959 Fisher's evidence shows Fisher's evidence shows
219 00:14:18,034 00:14:21,552 Just how sophisticated these hunters were. Just how sophisticated these hunters were.
220 00:14:21,561 00:14:24,512 Fisher: I think this comes from the base of the skull Fisher: I think this comes from the base of the skull
221 00:14:24,521 00:14:26,512 That was cleaved off. That was cleaved off.
222 00:14:26,521 00:14:28,512 This would suggest, not in a single piece, This would suggest, not in a single piece,
223 00:14:28,521 00:14:30,839 Maybe in multiple pieces, Maybe in multiple pieces,
224 00:14:30,914 00:14:34,352 We have this very targeted damage on the skull. We have this very targeted damage on the skull.
225 00:14:34,361 00:14:37,639 They broke in just where it was necessary They broke in just where it was necessary
226 00:14:37,714 00:14:40,359 To most easily remove the entire brain. To most easily remove the entire brain.
227 00:14:42,041 00:14:44,112 Narrator: The early humans aren't just eating Narrator: The early humans aren't just eating
228 00:14:44,121 00:14:46,192 The nutritious brain. The nutritious brain.
229 00:14:46,201 00:14:50,679 They know how to prepare and preserve it. They know how to prepare and preserve it.
230 00:14:50,754 00:14:53,559 Fisher: The fact that it's found in the pond Fisher: The fact that it's found in the pond
231 00:14:53,634 00:14:55,639 Is consistent with the notion Is consistent with the notion
232 00:14:55,714 00:14:59,792 That they store brains in skulls in lakes for a month or two That they store brains in skulls in lakes for a month or two
233 00:14:59,801 00:15:01,312 To sort of season them To sort of season them
234 00:15:01,321 00:15:05,319 And, and get them sort of to just the right consistency, And, and get them sort of to just the right consistency,
235 00:15:05,394 00:15:07,199 But then they'll eat them directly. But then they'll eat them directly.
236 00:15:10,754 00:15:14,079 Narrator: Mammoths once dominated this landscape. Narrator: Mammoths once dominated this landscape.
237 00:15:17,794 00:15:22,359 But fossil evidence shows that by 10,000 years ago, But fossil evidence shows that by 10,000 years ago,
238 00:15:22,434 00:15:26,832 Their numbers are in steep decline. Their numbers are in steep decline.
239 00:15:26,841 00:15:30,519 And the clues point to one culprit. And the clues point to one culprit.
240 00:15:33,401 00:15:35,552 Fisher: You might think that a small human population Fisher: You might think that a small human population
241 00:15:35,561 00:15:40,279 Would never make a dent in the populations like this, Would never make a dent in the populations like this,
242 00:15:40,354 00:15:44,039 But these are slow-reproducing animals. But these are slow-reproducing animals.
243 00:15:44,201 00:15:47,552 When they suffer losses to hunting year after year, When they suffer losses to hunting year after year,
244 00:15:47,561 00:15:50,039 It has the potential to have a serious impact It has the potential to have a serious impact
245 00:15:50,114 00:15:52,039 On the population as a whole. On the population as a whole.
246 00:15:55,794 00:15:58,912 The evidence strongly supports human activity The evidence strongly supports human activity
247 00:15:58,921 00:16:03,519 As the principal cause of the mammoths' extinction. As the principal cause of the mammoths' extinction.
248 00:16:07,161 00:16:09,392 Narrator: The end of the mammoths is proof Narrator: The end of the mammoths is proof
249 00:16:09,401 00:16:12,039 That as early as 10,000 years ago, That as early as 10,000 years ago,
250 00:16:12,114 00:16:15,872 Our adaptive brain gives us enormous influence Our adaptive brain gives us enormous influence
251 00:16:15,881 00:16:17,639 Over our environment. Over our environment.
252 00:16:19,554 00:16:22,352 But globally, our scattered populations But globally, our scattered populations
253 00:16:22,361 00:16:25,519 Still total fewer than five million. Still total fewer than five million.
254 00:16:27,721 00:16:30,359 In this ice age world, our numbers are limited In this ice age world, our numbers are limited
255 00:16:30,434 00:16:34,279 By the scarcity of the wild resources we depend on. By the scarcity of the wild resources we depend on.
256 00:16:37,641 00:16:40,839 But the planet itself will soon create opportunity But the planet itself will soon create opportunity
257 00:16:40,914 00:16:43,472 For a new way of life. For a new way of life.
258 00:16:43,481 00:16:47,479 Humans will harness the power of cultivation, Humans will harness the power of cultivation,
259 00:16:47,554 00:16:50,112 Transforming not just our population, Transforming not just our population,
260 00:16:50,121 00:16:54,919 But our societies, even the whole ecosystem. But our societies, even the whole ecosystem.
261 00:17:03,394 00:17:07,199 Our planet today is lit up by civilization. Our planet today is lit up by civilization.
262 00:17:15,161 00:17:18,112 But 10,000 years ago, But 10,000 years ago,
263 00:17:18,121 00:17:21,599 Not a single town or city exists. Not a single town or city exists.
264 00:17:25,074 00:17:27,792 All humans are nomads. All humans are nomads.
265 00:17:27,801 00:17:32,039 They live in small groups of hunter-gatherers, They live in small groups of hunter-gatherers,
266 00:17:32,121 00:17:34,199 Always on the move, Always on the move,
267 00:17:34,274 00:17:40,359 Hunting wild animals and foraging wild plants. Hunting wild animals and foraging wild plants.
268 00:17:40,434 00:17:45,479 This lifestyle has changed little for over 100,000 years. This lifestyle has changed little for over 100,000 years.
269 00:17:45,554 00:17:50,359 ? ?
270 00:17:50,434 00:17:55,239 But just 5,000 years later, grand structures appear But just 5,000 years later, grand structures appear
271 00:17:55,314 00:17:58,439 Alongside teeming cities, Alongside teeming cities,
272 00:17:58,514 00:18:01,319 Hallmarks of civilization. Hallmarks of civilization.
273 00:18:02,521 00:18:04,832 It's a dramatic turning point. It's a dramatic turning point.
274 00:18:04,841 00:18:08,759 ? ?
275 00:18:08,834 00:18:11,319 And a set of top secret photographs And a set of top secret photographs
276 00:18:11,394 00:18:14,679 May just have revealed where it all began. May just have revealed where it all began.
277 00:18:20,514 00:18:24,672 In the 1960s, at the height of the cold war, In the 1960s, at the height of the cold war,
278 00:18:24,681 00:18:28,119 America launches a spy satellite program... America launches a spy satellite program...
279 00:18:32,841 00:18:35,599 Code name: Corona. Code name: Corona.
280 00:18:39,401 00:18:42,919 For decades, the 800,000 satellite photographs For decades, the 800,000 satellite photographs
281 00:18:42,994 00:18:48,119 Of the corona program remain top secret, Of the corona program remain top secret,
282 00:18:48,194 00:18:52,999 But in 1995, an archaeologist from the smithsonian institution But in 1995, an archaeologist from the smithsonian institution
283 00:18:53,074 00:18:58,359 Persuades the government to declassify the images. Persuades the government to declassify the images.
284 00:18:58,434 00:19:00,199 This treasure trove of data This treasure trove of data
285 00:19:00,274 00:19:04,799 May just have identified the world's first city. May just have identified the world's first city.
286 00:19:08,921 00:19:12,919 Anthropologist dr. Jesse casana has spent years Anthropologist dr. Jesse casana has spent years
287 00:19:12,994 00:19:19,072 Studying corona spy photographs of the middle east. Studying corona spy photographs of the middle east.
288 00:19:19,081 00:19:21,072 The images are invaluable The images are invaluable
289 00:19:21,081 00:19:24,359 Because 50 years ago when the photos were taken, Because 50 years ago when the photos were taken,
290 00:19:24,434 00:19:28,512 The countryside was far less industrialized. The countryside was far less industrialized.
291 00:19:31,161 00:19:36,672 Ancient details remain visible, if you know what to look for. Ancient details remain visible, if you know what to look for.
292 00:19:36,681 00:19:38,359 Jesse casana: We were able to document Jesse casana: We were able to document
293 00:19:38,434 00:19:42,839 Something like 10,000 previously unknown archaeological sites Something like 10,000 previously unknown archaeological sites
294 00:19:42,914 00:19:46,032 That, through the history of 150 years That, through the history of 150 years
295 00:19:46,041 00:19:48,192 Of archaeologists working in the middle east, Of archaeologists working in the middle east,
296 00:19:48,201 00:19:50,079 No one had ever documented. No one had ever documented.
297 00:19:51,721 00:19:53,232 Narrator: In 2007, Narrator: In 2007,
298 00:19:53,241 00:19:57,079 The spy images herald a breakthrough, The spy images herald a breakthrough,
299 00:19:57,154 00:19:59,872 Revealing details that are causing experts Revealing details that are causing experts
300 00:19:59,881 00:20:05,199 To reclassify one settlement as the world's first city. To reclassify one settlement as the world's first city.
301 00:20:06,841 00:20:10,992 4,000 years older than the pyramids of egypt, 4,000 years older than the pyramids of egypt,
302 00:20:11,001 00:20:14,599 It's called tell brak. It's called tell brak.
303 00:20:14,674 00:20:17,072 Casana: It looks like a gigantic hill today, Casana: It looks like a gigantic hill today,
304 00:20:17,081 00:20:21,079 And surrounding the big hill is a fan of other settlement And surrounding the big hill is a fan of other settlement
305 00:20:21,154 00:20:24,279 That encompasses a very large area. That encompasses a very large area.
306 00:20:24,354 00:20:26,759 It's the remains of an ancient city It's the remains of an ancient city
307 00:20:26,834 00:20:31,792 That was probably first founded more than 6,000 years ago, That was probably first founded more than 6,000 years ago,
308 00:20:31,801 00:20:37,079 And that makes it perhaps the oldest city in the world. And that makes it perhaps the oldest city in the world.
309 00:20:37,154 00:20:40,599 Narrator: Settlements like tell brak only start to appear Narrator: Settlements like tell brak only start to appear
310 00:20:40,674 00:20:45,039 After a dramatic event transforms the environment. After a dramatic event transforms the environment.
311 00:20:48,681 00:20:53,072 It's the end of the last ice age. It's the end of the last ice age.
312 00:20:53,121 00:20:56,039 Earth's climate radically shifts. Earth's climate radically shifts.
313 00:20:56,114 00:21:04,512 ? ?
314 00:21:04,521 00:21:11,319 The planet is at its warmest point in 100,000 years. The planet is at its warmest point in 100,000 years.
315 00:21:11,394 00:21:15,199 Where tell brak lies is an area of the middle east Where tell brak lies is an area of the middle east
316 00:21:15,241 00:21:18,672 Known as the fertile crescent. Known as the fertile crescent.
317 00:21:18,681 00:21:22,039 It's now that it becomes fertile. It's now that it becomes fertile.
318 00:21:22,121 00:21:26,352 ? ?
319 00:21:26,361 00:21:30,192 Rainfall and temperatures increase, Rainfall and temperatures increase,
320 00:21:30,201 00:21:34,039 Leading to a great expansion of grassland. Leading to a great expansion of grassland.
321 00:21:34,114 00:21:40,839 ? ?
322 00:21:40,914 00:21:45,479 Climate change is about to fuel a food revolution. Climate change is about to fuel a food revolution.
323 00:21:47,954 00:21:53,552 For millennia, humans foraged wild grass seeds, For millennia, humans foraged wild grass seeds,
324 00:21:53,561 00:21:56,432 But now abundant wheat and barley But now abundant wheat and barley
325 00:21:56,441 00:21:59,679 Prove easy to grow and to control. Prove easy to grow and to control.
326 00:22:02,274 00:22:04,359 Some people begin to settle, Some people begin to settle,
327 00:22:04,434 00:22:09,872 To nurture and protect their crops. To nurture and protect their crops.
328 00:22:09,881 00:22:13,399 They gradually give up the hunter-gatherer lifestyle They gradually give up the hunter-gatherer lifestyle
329 00:22:13,474 00:22:18,352 To become farmers. To become farmers.
330 00:22:18,361 00:22:20,079 From this point forward, From this point forward,
331 00:22:20,121 00:22:25,072 Human reliance on cultivated plants and domesticated animals Human reliance on cultivated plants and domesticated animals
332 00:22:25,121 00:22:27,759 Will begin to change the landscape. Will begin to change the landscape.
333 00:22:31,081 00:22:34,592 Potts: With agriculture, people began to have an impact, Potts: With agriculture, people began to have an impact,
334 00:22:34,601 00:22:37,792 Taking a few plants, then breeding them, Taking a few plants, then breeding them,
335 00:22:37,801 00:22:41,399 Growing them, and rejecting all of the other plants around them, Growing them, and rejecting all of the other plants around them,
336 00:22:41,474 00:22:44,832 Simplifying those ecosystems. Simplifying those ecosystems.
337 00:22:44,841 00:22:48,079 Narrator: Tell brak is special because the earliest evidence Narrator: Tell brak is special because the earliest evidence
338 00:22:48,121 00:22:49,792 Of this shift to agriculture Of this shift to agriculture
339 00:22:49,801 00:22:52,912 Is visible in the corona images-- Is visible in the corona images--
340 00:22:52,921 00:22:55,319 The world's first roads. The world's first roads.
341 00:22:55,394 00:22:56,672 Casana: What we can see Casana: What we can see
342 00:22:56,681 00:22:59,072 Are these, these dark linear features Are these, these dark linear features
343 00:22:59,121 00:23:03,472 That extend out from the site like the spokes on a wheel. That extend out from the site like the spokes on a wheel.
344 00:23:03,481 00:23:04,999 They're really long. They're really long.
345 00:23:05,074 00:23:08,512 They extend four or five kilometers, and what they are They extend four or five kilometers, and what they are
346 00:23:08,521 00:23:12,279 Are the remains of probably the earliest known roadways Are the remains of probably the earliest known roadways
347 00:23:12,354 00:23:14,272 In the world. In the world.
348 00:23:14,281 00:23:15,952 What we are able to reconstruct What we are able to reconstruct
349 00:23:15,961 00:23:19,152 Is that, in the immediate hinterland surrounding the city, Is that, in the immediate hinterland surrounding the city,
350 00:23:19,161 00:23:21,072 There would have been extensive fields There would have been extensive fields
351 00:23:21,201 00:23:25,392 Of intensively cultivated wheat and barley. Of intensively cultivated wheat and barley.
352 00:23:25,401 00:23:27,159 The sheep and goat that lived with the people The sheep and goat that lived with the people
353 00:23:27,234 00:23:28,439 Here in tell brak, Here in tell brak,
354 00:23:28,514 00:23:31,792 They would need to pass by those fields, They would need to pass by those fields,
355 00:23:31,801 00:23:33,152 And they didn't want to trample the wheat, And they didn't want to trample the wheat,
356 00:23:33,161 00:23:35,072 So they would be kind of constrained, So they would be kind of constrained,
357 00:23:35,081 00:23:37,159 And so that's how we get these roadways forming. And so that's how we get these roadways forming.
358 00:23:37,234 00:23:38,752 They served as passage They served as passage
359 00:23:38,761 00:23:41,479 For large herds of sheep and goat and other animals For large herds of sheep and goat and other animals
360 00:23:41,554 00:23:43,799 To come in and out of the city. To come in and out of the city.
361 00:23:46,201 00:23:49,392 Narrator: The settled populations expand, Narrator: The settled populations expand,
362 00:23:49,401 00:23:53,072 Overwhelming the remaining hunter-gatherers, Overwhelming the remaining hunter-gatherers,
363 00:23:53,081 00:23:56,079 Transforming the landscape Transforming the landscape
364 00:23:56,121 00:24:01,079 With fields, villages, towns, With fields, villages, towns,
365 00:24:01,154 00:24:05,152 And eventually cities. And eventually cities.
366 00:24:05,161 00:24:09,952 As these cities become the hubs of great civilizations, As these cities become the hubs of great civilizations,
367 00:24:09,961 00:24:14,919 This is the moment humanity becomes visible from space. This is the moment humanity becomes visible from space.
368 00:24:16,914 00:24:19,239 Over the next few thousand years, Over the next few thousand years,
369 00:24:19,314 00:24:24,112 Agricultural revolutions occur across the globe. Agricultural revolutions occur across the globe.
370 00:24:24,121 00:24:26,039 Each civilization is built Each civilization is built
371 00:24:26,114 00:24:31,152 Around locally cultivated plants. Around locally cultivated plants.
372 00:24:31,161 00:24:35,319 In china and southeast asia, rice and millet. In china and southeast asia, rice and millet.
373 00:24:35,394 00:24:38,839 In the americas, corn or potatoes. In the americas, corn or potatoes.
374 00:24:41,721 00:24:44,119 And wherever agriculture takes hold, And wherever agriculture takes hold,
375 00:24:44,194 00:24:48,352 There is a population explosion. There is a population explosion.
376 00:24:48,361 00:24:50,359 By the first century a.D., By the first century a.D.,
377 00:24:50,434 00:24:55,392 The world population is over 170 million. The world population is over 170 million.
378 00:24:55,401 00:24:59,159 By 1500, it's 500 million. By 1500, it's 500 million.
379 00:25:02,441 00:25:05,632 The footprint of expanding human populations The footprint of expanding human populations
380 00:25:05,641 00:25:10,119 Spreads over the entire surface of the earth. Spreads over the entire surface of the earth.
381 00:25:10,194 00:25:12,592 But now, as long as we rely solely But now, as long as we rely solely
382 00:25:12,601 00:25:15,079 On plants and animals for energy, On plants and animals for energy,
383 00:25:15,154 00:25:18,599 Our growth is constrained. Our growth is constrained.
384 00:25:21,481 00:25:23,792 Further progress is unlikely Further progress is unlikely
385 00:25:23,801 00:25:29,239 If not for a hidden source of power lying under our feet. If not for a hidden source of power lying under our feet.
386 00:25:34,274 00:25:36,039 Above our heads today, Above our heads today,
387 00:25:36,161 00:25:39,559 Scores of satellites orbit the earth. Scores of satellites orbit the earth.
388 00:25:39,634 00:25:42,999 Their mission--treasure seeking. Their mission--treasure seeking.
389 00:25:45,234 00:25:49,872 Using an array of sensors, they probe the planet's surface, Using an array of sensors, they probe the planet's surface,
390 00:25:49,881 00:25:51,479 Seeking an energy bonanza Seeking an energy bonanza
391 00:25:51,554 00:25:54,759 Buried hundreds of millions of years ago. Buried hundreds of millions of years ago.
392 00:25:54,834 00:25:59,319 ? ?
393 00:25:59,394 00:26:02,672 Over the earth's 4.5-billion-year history, Over the earth's 4.5-billion-year history,
394 00:26:02,681 00:26:06,519 It has experienced many violent transformations. It has experienced many violent transformations.
395 00:26:09,881 00:26:11,199 But through them all, But through them all,
396 00:26:11,241 00:26:15,399 The sun has shone, bathing the surface with light, The sun has shone, bathing the surface with light,
397 00:26:15,474 00:26:18,519 A source of incredible energy. A source of incredible energy.
398 00:26:18,594 00:26:24,112 ? ?
399 00:26:24,121 00:26:26,519 When life takes off in earnest, When life takes off in earnest,
400 00:26:26,594 00:26:30,079 It does so because it has perfected photosynthesis... It does so because it has perfected photosynthesis...
401 00:26:32,521 00:26:36,112 Using light energy to trap carbon from the air Using light energy to trap carbon from the air
402 00:26:36,121 00:26:42,079 In leaves, stems, and trunks. In leaves, stems, and trunks.
403 00:26:42,121 00:26:48,199 For over 100 million years, immense forests swamp the globe, For over 100 million years, immense forests swamp the globe,
404 00:26:48,274 00:26:53,079 And the seas fill with life. And the seas fill with life.
405 00:26:53,154 00:26:59,632 As plants and animals die, their remains become fossilized. As plants and animals die, their remains become fossilized.
406 00:26:59,641 00:27:02,832 They lock up the solar energy that created them They lock up the solar energy that created them
407 00:27:02,841 00:27:08,032 In coal, oil, and gas, In coal, oil, and gas,
408 00:27:08,041 00:27:09,872 Which millions of years later Which millions of years later
409 00:27:09,881 00:27:13,952 Will utterly transform human societies. Will utterly transform human societies.
410 00:27:13,961 00:27:23,999 ? ?
411 00:27:24,001 00:27:29,879 ? ?
412 00:27:29,954 00:27:32,432 Since the start of civilization, Since the start of civilization,
413 00:27:32,441 00:27:34,432 To keep the fires burning, To keep the fires burning,
414 00:27:34,441 00:27:37,792 Populations rely on wood for fuel. Populations rely on wood for fuel.
415 00:27:37,801 00:27:45,872 ? ?
416 00:27:45,881 00:27:48,272 And by around 300 years ago, And by around 300 years ago,
417 00:27:48,281 00:27:51,392 Populated areas like europe and china Populated areas like europe and china
418 00:27:51,401 00:27:56,032 Burn up most of their forests. Burn up most of their forests.
419 00:27:56,041 00:27:58,352 If they use up all their wood, If they use up all their wood,
420 00:27:58,361 00:28:01,719 Their civilizations may soon collapse. Their civilizations may soon collapse.
421 00:28:06,194 00:28:08,079 But in the 18th century, But in the 18th century,
422 00:28:08,121 00:28:12,359 Humans tap the true potential of fossil fuels... Humans tap the true potential of fossil fuels...
423 00:28:14,281 00:28:16,272 Developing machines to harness Developing machines to harness
424 00:28:16,281 00:28:19,559 This buried source of rich energy. This buried source of rich energy.
425 00:28:22,994 00:28:24,912 Over just a few hundred years, Over just a few hundred years,
426 00:28:24,921 00:28:28,999 They fuel humanity's great leap forward-- They fuel humanity's great leap forward--
427 00:28:29,074 00:28:33,472 The industrial revolution. The industrial revolution.
428 00:28:33,481 00:28:36,679 Scott wing: We're tapping into this fossilized source of carbon Scott wing: We're tapping into this fossilized source of carbon
429 00:28:36,754 00:28:40,199 That's been deposited over hundreds of millions of years, That's been deposited over hundreds of millions of years,
430 00:28:40,274 00:28:42,432 And we're then burning that energy up, And we're then burning that energy up,
431 00:28:42,441 00:28:46,199 And that's really an energy revolution that's so recent And that's really an energy revolution that's so recent
432 00:28:46,274 00:28:47,312 That I, I think sometimes That I, I think sometimes
433 00:28:47,321 00:28:49,952 We don't realize how important it is. We don't realize how important it is.
434 00:28:49,961 00:28:54,599 ? ?
435 00:28:54,674 00:28:56,839 Narrator: Access to fossilized energy Narrator: Access to fossilized energy
436 00:28:56,914 00:29:00,479 Puts human civilization into overdrive. Puts human civilization into overdrive.
437 00:29:02,761 00:29:06,192 Wing: The energy revolution lets all of us Wing: The energy revolution lets all of us
438 00:29:06,201 00:29:10,112 Consume a huge amount of power. Consume a huge amount of power.
439 00:29:10,121 00:29:15,119 The amount of energy that each one of us use in our daily lives The amount of energy that each one of us use in our daily lives
440 00:29:15,161 00:29:16,599 Is equivalent to having, Is equivalent to having,
441 00:29:16,674 00:29:19,519 You know, more than 100 people working for you full-time. You know, more than 100 people working for you full-time.
442 00:29:21,794 00:29:25,279 Narrator: Gasoline-fueled vehicles link cities. Narrator: Gasoline-fueled vehicles link cities.
443 00:29:28,521 00:29:32,639 Coal- and oil-powered ships link continents. Coal- and oil-powered ships link continents.
444 00:29:37,714 00:29:41,719 Technological innovation allows instant communication Technological innovation allows instant communication
445 00:29:41,794 00:29:44,272 Across the planet. Across the planet.
446 00:29:44,281 00:29:48,079 Civilization is now truly global. Civilization is now truly global.
447 00:29:52,114 00:29:53,552 But this energy revolution But this energy revolution
448 00:29:53,561 00:29:56,439 Also unleashes humanity's potential Also unleashes humanity's potential
449 00:29:56,514 00:30:00,079 For incredible destructive power. For incredible destructive power.
450 00:30:00,121 00:30:05,799 [explosion] [explosion]
451 00:30:05,874 00:30:08,519 The explosion of the first atomic bomb The explosion of the first atomic bomb
452 00:30:08,594 00:30:11,679 Marks a turning point for humankind. Marks a turning point for humankind.
453 00:30:14,161 00:30:18,959 [explosion] [explosion]
454 00:30:21,001 00:30:22,672 Over the following decades, Over the following decades,
455 00:30:22,681 00:30:26,512 More than 2,000 atomic warheads are tested. More than 2,000 atomic warheads are tested.
456 00:30:26,521 00:30:31,792 ? ?
457 00:30:31,801 00:30:36,352 They generate an unprecedented release of radioactive dust They generate an unprecedented release of radioactive dust
458 00:30:36,361 00:30:39,359 That spreads across the globe. That spreads across the globe.
459 00:30:41,641 00:30:44,839 Wing: If you were a geologist ten million years from now, Wing: If you were a geologist ten million years from now,
460 00:30:44,914 00:30:47,799 Some of it would still be visible Some of it would still be visible
461 00:30:47,874 00:30:53,072 In the sediments deposited in the mid-20th century. In the sediments deposited in the mid-20th century.
462 00:30:53,081 00:30:54,759 Narrator: This is the moment Narrator: This is the moment
463 00:30:54,834 00:30:59,639 Geologists consider the official start of the age of humans, Geologists consider the official start of the age of humans,
464 00:30:59,714 00:31:02,679 The point when a species of ape achieved the power The point when a species of ape achieved the power
465 00:31:02,754 00:31:06,839 To determine the destiny of all life on earth. To determine the destiny of all life on earth.
466 00:31:13,161 00:31:16,439 So far, the fear of mutual destruction So far, the fear of mutual destruction
467 00:31:16,514 00:31:19,559 Has kept us from nuclear holocaust. Has kept us from nuclear holocaust.
468 00:31:22,441 00:31:24,039 But in the age of humans, But in the age of humans,
469 00:31:24,114 00:31:27,872 There are other ways we can threaten our own survival. There are other ways we can threaten our own survival.
470 00:31:27,881 00:31:35,559 ? ?
471 00:31:35,634 00:31:38,759 It took humanity 300,000 years It took humanity 300,000 years
472 00:31:38,834 00:31:43,399 To reach a population of one billion. To reach a population of one billion.
473 00:31:43,474 00:31:45,632 But in just two centuries, But in just two centuries,
474 00:31:45,641 00:31:52,199 Our fossil-fueled civilization has rocketed to seven billion. Our fossil-fueled civilization has rocketed to seven billion.
475 00:31:52,274 00:31:55,792 We are now spread, in increasing density, We are now spread, in increasing density,
476 00:31:55,801 00:32:02,592 Over the entire habitable surface of the globe. Over the entire habitable surface of the globe.
477 00:32:02,601 00:32:04,039 Kirk johnson: During my life span, Kirk johnson: During my life span,
478 00:32:04,121 00:32:07,232 The population of the planet has more than doubled. The population of the planet has more than doubled.
479 00:32:07,241 00:32:08,992 The impact of that, of course, The impact of that, of course,
480 00:32:09,001 00:32:13,072 Is that people need food, land, iphones, Is that people need food, land, iphones,
481 00:32:13,081 00:32:15,359 Cars, buses, cities. Cars, buses, cities.
482 00:32:16,914 00:32:20,512 So as humans grow, they're appropriating the natural world So as humans grow, they're appropriating the natural world
483 00:32:20,521 00:32:22,799 At a staggering rate. At a staggering rate.
484 00:32:24,594 00:32:27,232 Narrator: It's estimated that to feed everyone, Narrator: It's estimated that to feed everyone,
485 00:32:27,241 00:32:28,759 Farmers will need to produce Farmers will need to produce
486 00:32:28,834 00:32:31,479 As much food in the next 40 years As much food in the next 40 years
487 00:32:31,554 00:32:35,199 As they have in the previous 8,000. As they have in the previous 8,000.
488 00:32:38,361 00:32:41,559 But as we turn most of the globe to agriculture, But as we turn most of the globe to agriculture,
489 00:32:41,634 00:32:44,879 We are destroying animal diversity. We are destroying animal diversity.
490 00:32:47,314 00:32:49,472 Today, livestock farming Today, livestock farming
491 00:32:49,481 00:32:52,999 Covers a quarter of all available land. Covers a quarter of all available land.
492 00:32:56,754 00:33:00,199 In just 50 years, wild mammal numbers In just 50 years, wild mammal numbers
493 00:33:00,274 00:33:03,519 Have dropped by almost 60 percent. Have dropped by almost 60 percent.
494 00:33:06,994 00:33:08,592 Johnson: One of the things we've been seeing is over time Johnson: One of the things we've been seeing is over time
495 00:33:08,601 00:33:12,039 Is that there are less animals than there used to be. Is that there are less animals than there used to be.
496 00:33:12,121 00:33:13,712 There are less fish than there used to be. There are less fish than there used to be.
497 00:33:13,721 00:33:16,439 There's less wild land than there used to be. There's less wild land than there used to be.
498 00:33:19,634 00:33:22,999 Narrator: Extinction rates are 1,000 times higher Narrator: Extinction rates are 1,000 times higher
499 00:33:23,074 00:33:25,039 Than ever measured before. Than ever measured before.
500 00:33:27,234 00:33:29,392 Wing: How long are we going to continue Wing: How long are we going to continue
501 00:33:29,401 00:33:33,559 To decrease the habitat for other species? To decrease the habitat for other species?
502 00:33:33,634 00:33:36,999 Because if it continues, I think there's not much doubt Because if it continues, I think there's not much doubt
503 00:33:37,074 00:33:39,479 That we will end up in a mass extinction. That we will end up in a mass extinction.
504 00:33:43,154 00:33:44,432 Narrator: We may not notice Narrator: We may not notice
505 00:33:44,441 00:33:48,199 The extinction of most wild animals, The extinction of most wild animals,
506 00:33:48,274 00:33:51,079 But our addiction to fossilized energy But our addiction to fossilized energy
507 00:33:51,154 00:33:53,959 Is becoming impossible to ignore. Is becoming impossible to ignore.
508 00:33:54,034 00:34:00,999 ? ?
509 00:34:01,074 00:34:04,199 Burning fossil fuels pumps huge quantities Burning fossil fuels pumps huge quantities
510 00:34:04,274 00:34:06,799 Of ancient carbon into the atmosphere... Of ancient carbon into the atmosphere...
511 00:34:10,514 00:34:14,672 Far too much for today's plants, soils, or oceans Far too much for today's plants, soils, or oceans
512 00:34:14,681 00:34:16,039 To reabsorb. To reabsorb.
513 00:34:16,161 00:34:19,792 ? ?
514 00:34:19,801 00:34:24,039 [horns honking] [horns honking]
515 00:34:24,201 00:34:26,439 Wing: We're using the fossil fuel reservoir Wing: We're using the fossil fuel reservoir
516 00:34:26,514 00:34:29,632 A million times faster than it was generated, A million times faster than it was generated,
517 00:34:29,641 00:34:34,672 And there are climatic and ecosystem consequences to that And there are climatic and ecosystem consequences to that
518 00:34:34,681 00:34:39,559 That are going to be present for thousands of years to come. That are going to be present for thousands of years to come.
519 00:34:43,234 00:34:44,839 Narrator: Measurements from space probes Narrator: Measurements from space probes
520 00:34:44,914 00:34:51,792 Confirm that our atmosphere is altering at an alarming rate. Confirm that our atmosphere is altering at an alarming rate.
521 00:34:51,801 00:34:53,392 Gavin schmidt: We've increased the amount of carbon dioxide Gavin schmidt: We've increased the amount of carbon dioxide
522 00:34:53,401 00:34:54,839 By more than 40 percent. By more than 40 percent.
523 00:34:54,914 00:34:56,592 We've more than doubled the amount of methane, We've more than doubled the amount of methane,
524 00:34:56,601 00:34:58,272 Another trace gas in the atmosphere. Another trace gas in the atmosphere.
525 00:34:58,281 00:35:01,239 Each one of those things is changing the climate, Each one of those things is changing the climate,
526 00:35:01,314 00:35:02,599 Is changing the weather. Is changing the weather.
527 00:35:02,674 00:35:04,512 Narrator: Earth's history tells us Narrator: Earth's history tells us
528 00:35:04,521 00:35:08,439 Rapid change in climate can be disastrous. Rapid change in climate can be disastrous.
529 00:35:08,514 00:35:11,159 Wing: We have past examples Wing: We have past examples
530 00:35:11,234 00:35:13,239 Where the amount of co2 has gone up Where the amount of co2 has gone up
531 00:35:13,314 00:35:15,159 And the earth's climate has warmed, And the earth's climate has warmed,
532 00:35:15,234 00:35:18,519 So it's a fact. So it's a fact.
533 00:35:18,594 00:35:20,832 Narrator: 56 million years ago, Narrator: 56 million years ago,
534 00:35:20,841 00:35:24,432 The climate warmed nearly 14 degrees fahrenheit The climate warmed nearly 14 degrees fahrenheit
535 00:35:24,441 00:35:27,152 Over a few thousand years. Over a few thousand years.
536 00:35:27,161 00:35:29,879 Fossils show that to survive the conditions, Fossils show that to survive the conditions,
537 00:35:29,954 00:35:35,719 Most species of mammal shrank in size by over a third. Most species of mammal shrank in size by over a third.
538 00:35:35,794 00:35:37,072 But under our watch, But under our watch,
539 00:35:37,081 00:35:42,512 The climate is changing at a much faster pace. The climate is changing at a much faster pace.
540 00:35:42,521 00:35:44,199 In the last two centuries, In the last two centuries,
541 00:35:44,274 00:35:48,352 Ocean acidity increased by 25 percent. Ocean acidity increased by 25 percent.
542 00:35:48,361 00:35:52,912 In the last 100 years, sea levels rose 8 inches, In the last 100 years, sea levels rose 8 inches,
543 00:35:52,921 00:35:54,752 And in just 50 years, And in just 50 years,
544 00:35:54,761 00:35:59,792 Nearly half of our arctic ice has disappeared. Nearly half of our arctic ice has disappeared.
545 00:35:59,801 00:36:04,352 We are creating a new planetary environment. We are creating a new planetary environment.
546 00:36:04,361 00:36:06,192 Schmidt: We're pushing a system Schmidt: We're pushing a system
547 00:36:06,201 00:36:09,072 In a direction that it's never been before. In a direction that it's never been before.
548 00:36:09,081 00:36:10,672 Just in the space of 150 years, Just in the space of 150 years,
549 00:36:10,681 00:36:13,639 We have become a geological force We have become a geological force
550 00:36:13,714 00:36:16,752 To, to match almost anything that you see To, to match almost anything that you see
551 00:36:16,761 00:36:20,192 In, in a billion years of earth history. In, in a billion years of earth history.
552 00:36:20,201 00:36:23,119 Narrator: We face a calamity of our own making, Narrator: We face a calamity of our own making,
553 00:36:23,161 00:36:25,239 But our species came this far But our species came this far
554 00:36:25,314 00:36:29,792 Through brain power and the tools we created, Through brain power and the tools we created,
555 00:36:29,801 00:36:33,439 So can our tools come to our rescue? So can our tools come to our rescue?
556 00:36:36,841 00:36:40,272 The problems caused by humanity's great expansion The problems caused by humanity's great expansion
557 00:36:40,281 00:36:43,399 Have been brewing for centuries. Have been brewing for centuries.
558 00:36:43,474 00:36:45,072 But scientists believe But scientists believe
559 00:36:45,201 00:36:48,279 It's the actions of this current generation It's the actions of this current generation
560 00:36:48,354 00:36:52,439 That will decide the future of the planet. That will decide the future of the planet.
561 00:36:52,514 00:36:54,519 Potts: Humans are a turning point Potts: Humans are a turning point
562 00:36:54,594 00:36:56,599 In the history of life on earth. In the history of life on earth.
563 00:36:56,674 00:36:58,352 We've become a global phenomenon We've become a global phenomenon
564 00:36:58,361 00:37:00,839 And responsible for the intensity And responsible for the intensity
565 00:37:00,914 00:37:03,399 Of what is going on to our planet, Of what is going on to our planet,
566 00:37:03,474 00:37:04,992 To the ecosystems on which To the ecosystems on which
567 00:37:05,001 00:37:08,199 Not only other organisms, but human life depends. Not only other organisms, but human life depends.
568 00:37:08,274 00:37:10,272 This is, in many ways, This is, in many ways,
569 00:37:10,281 00:37:14,519 Our own survival challenge for the future. Our own survival challenge for the future.
570 00:37:14,594 00:37:19,119 Narrator: And now we have technology to help us, Narrator: And now we have technology to help us,
571 00:37:19,161 00:37:24,319 Satellites to monitor our planet and help find solutions. Satellites to monitor our planet and help find solutions.
572 00:37:27,081 00:37:32,719 Our orbiting probes have already helped avert a global disaster. Our orbiting probes have already helped avert a global disaster.
573 00:37:34,834 00:37:38,279 In the 1980s, above antarctica, In the 1980s, above antarctica,
574 00:37:38,354 00:37:41,479 Nasa satellites provide crucial confirmation Nasa satellites provide crucial confirmation
575 00:37:41,554 00:37:46,032 Of a gaping hole in the ozone layer. Of a gaping hole in the ozone layer.
576 00:37:46,041 00:37:49,399 This thin layer of gas high in the atmosphere This thin layer of gas high in the atmosphere
577 00:37:49,474 00:37:55,639 Is a vital protective shield against the harshest solar rays. Is a vital protective shield against the harshest solar rays.
578 00:37:55,714 00:37:57,872 Schmidt: We tan, we enjoy being in the sun, Schmidt: We tan, we enjoy being in the sun,
579 00:37:57,881 00:38:00,352 But if we were in the sun without an ozone layer, But if we were in the sun without an ozone layer,
580 00:38:00,361 00:38:02,032 We would burn almost instantly, We would burn almost instantly,
581 00:38:02,041 00:38:04,599 And it would be very, very difficult for life to exist. And it would be very, very difficult for life to exist.
582 00:38:07,794 00:38:10,039 Narrator: The culprit is a side-product Narrator: The culprit is a side-product
583 00:38:10,121 00:38:12,039 Of globalized industry, Of globalized industry,
584 00:38:12,114 00:38:15,072 Ozone-destroying man-made gases Ozone-destroying man-made gases
585 00:38:15,081 00:38:18,079 Used in aerosols and refrigeration. Used in aerosols and refrigeration.
586 00:38:20,441 00:38:22,519 Spurred by the satellite evidence, Spurred by the satellite evidence,
587 00:38:22,594 00:38:27,119 Politicians around the world unite in action. Politicians around the world unite in action.
588 00:38:27,161 00:38:29,392 Margaret thatcher: No one can opt out. Margaret thatcher: No one can opt out.
589 00:38:29,401 00:38:31,559 Narrator: The chemicals are banned. Narrator: The chemicals are banned.
590 00:38:35,321 00:38:36,679 Decades later, Decades later,
591 00:38:36,754 00:38:40,679 Ozone levels are on the road to recovery. Ozone levels are on the road to recovery.
592 00:38:40,754 00:38:45,072 Schmidt: We avoided the cliff. Nobody predicted this. Schmidt: We avoided the cliff. Nobody predicted this.
593 00:38:45,081 00:38:46,272 What would have happened? What would have happened?
594 00:38:46,281 00:38:51,239 It would have reconfigured life on earth. It would have reconfigured life on earth.
595 00:38:51,314 00:38:54,839 Narrator: Space technology helped prevent disaster. Narrator: Space technology helped prevent disaster.
596 00:38:57,161 00:38:58,439 Given the chance, Given the chance,
597 00:38:58,514 00:39:02,359 The atmosphere has the power to heal itself. The atmosphere has the power to heal itself.
598 00:39:08,434 00:39:12,439 Other satellite studies show that some animal species Other satellite studies show that some animal species
599 00:39:12,514 00:39:16,799 Also appear to show resilience in the age of humans. Also appear to show resilience in the age of humans.
600 00:39:20,114 00:39:22,039 In downtown chicago, In downtown chicago,
601 00:39:22,201 00:39:25,952 Dr. Stan gehrt uses gps technology Dr. Stan gehrt uses gps technology
602 00:39:25,961 00:39:29,239 To study a population of coyotes. To study a population of coyotes.
603 00:39:33,794 00:39:35,232 Stan gehrt: It's extremely difficult for us Stan gehrt: It's extremely difficult for us
604 00:39:35,241 00:39:37,952 To even pick up their signals on the ground, To even pick up their signals on the ground,
605 00:39:37,961 00:39:40,039 But the satellites can pick them up. But the satellites can pick them up.
606 00:39:42,441 00:39:45,472 Narrator: Radio-collaring over 400 coyotes, Narrator: Radio-collaring over 400 coyotes,
607 00:39:45,481 00:39:50,279 Gehrt documents how this species is thriving in the human world. Gehrt documents how this species is thriving in the human world.
608 00:39:50,354 00:39:55,872 ? ?
609 00:39:55,881 00:39:59,719 Gehrt: One of the most amazing things is just how many coyotes Gehrt: One of the most amazing things is just how many coyotes
610 00:39:59,794 00:40:03,079 Can live in a major metropolitan area Can live in a major metropolitan area
611 00:40:03,154 00:40:05,072 And live so close to people. And live so close to people.
612 00:40:05,201 00:40:09,639 We estimate that there's 3,000 to 4,000 coyotes here. We estimate that there's 3,000 to 4,000 coyotes here.
613 00:40:12,361 00:40:14,352 We have coyotes that are literally We have coyotes that are literally
614 00:40:14,361 00:40:17,799 Within just a few yards from people on a regular basis Within just a few yards from people on a regular basis
615 00:40:17,874 00:40:21,319 With people not knowing that they're there. With people not knowing that they're there.
616 00:40:21,394 00:40:23,319 Narrator: They survive by adapting Narrator: They survive by adapting
617 00:40:23,394 00:40:26,279 To the urban environment. To the urban environment.
618 00:40:26,354 00:40:28,199 Gehrt: Coyotes have to learn traffic patterns. Gehrt: Coyotes have to learn traffic patterns.
619 00:40:28,274 00:40:30,079 They have to learn how to cross roads They have to learn how to cross roads
620 00:40:30,121 00:40:31,959 And avoid getting hit by cars, And avoid getting hit by cars,
621 00:40:32,034 00:40:36,079 And that is the biggest risk to their life down here, And that is the biggest risk to their life down here,
622 00:40:36,121 00:40:37,999 And yet they're able to do that. And yet they're able to do that.
623 00:40:39,641 00:40:41,152 The patterns that we're seeing in chicago The patterns that we're seeing in chicago
624 00:40:41,161 00:40:42,839 With coyotes moving into the city With coyotes moving into the city
625 00:40:42,914 00:40:46,272 Is being seen in virtually every single metropolitan area Is being seen in virtually every single metropolitan area
626 00:40:46,281 00:40:47,839 Across north america. Across north america.
627 00:40:49,161 00:40:52,992 [train horn blows] [train horn blows]
628 00:40:53,001 00:40:56,079 Narrator: If we can make space for nature, Narrator: If we can make space for nature,
629 00:40:56,121 00:40:59,119 It can survive alongside us. It can survive alongside us.
630 00:41:05,234 00:41:06,839 Satellites can also provide Satellites can also provide
631 00:41:06,914 00:41:10,159 A path to preserving animal diversity. A path to preserving animal diversity.
632 00:41:12,274 00:41:14,119 Radio-tagging technology Radio-tagging technology
633 00:41:14,194 00:41:17,799 Allows the mapping of wildlife migration routes Allows the mapping of wildlife migration routes
634 00:41:17,874 00:41:20,759 Thousands of miles long, Thousands of miles long,
635 00:41:20,834 00:41:24,039 Maps we can use to create protected corridors Maps we can use to create protected corridors
636 00:41:24,201 00:41:28,832 To save species from human interference. To save species from human interference.
637 00:41:28,841 00:41:30,352 It's just one example It's just one example
638 00:41:30,361 00:41:35,632 Of how space data helps protect our planet. Of how space data helps protect our planet.
639 00:41:35,641 00:41:37,719 Johnson: Truly we live in a remarkable time, Johnson: Truly we live in a remarkable time,
640 00:41:37,794 00:41:40,352 When we as humans have technology, When we as humans have technology,
641 00:41:40,361 00:41:42,119 We have the ability to plan ahead, We have the ability to plan ahead,
642 00:41:42,194 00:41:44,592 We know our geologic past. We know our geologic past.
643 00:41:44,601 00:41:46,032 We can put all that together We can put all that together
644 00:41:46,041 00:41:49,232 And actually conceive of a desirable future And actually conceive of a desirable future
645 00:41:49,241 00:41:51,639 And build a global plan to get to that future. And build a global plan to get to that future.
646 00:41:51,714 00:41:56,039 That's the challenge for humanity in the 21st century. That's the challenge for humanity in the 21st century.
647 00:41:56,114 00:42:00,199 ? ?
648 00:42:00,274 00:42:01,632 Narrator: From our perspective, Narrator: From our perspective,
649 00:42:01,641 00:42:05,072 Our human story is epic in scope. Our human story is epic in scope.
650 00:42:05,081 00:42:10,679 ? ?
651 00:42:10,754 00:42:14,559 Our civilization is measured in thousands of years... Our civilization is measured in thousands of years...
652 00:42:18,201 00:42:21,392 Our species in hundreds of thousands. Our species in hundreds of thousands.
653 00:42:21,401 00:42:29,239 ? ?
654 00:42:29,314 00:42:31,239 But the earth measures time But the earth measures time
655 00:42:31,314 00:42:34,319 In millions and billions of years. In millions and billions of years.
656 00:42:37,081 00:42:43,399 Our planet has lived only half of its life span. Our planet has lived only half of its life span.
657 00:42:43,474 00:42:46,759 For the last 4.5 billion years, For the last 4.5 billion years,
658 00:42:46,834 00:42:50,672 It has experienced monumental change. It has experienced monumental change.
659 00:42:50,681 00:42:54,439 Species that dominate then disappear, Species that dominate then disappear,
660 00:42:54,514 00:42:59,072 Giving rise to new life. Giving rise to new life.
661 00:42:59,081 00:43:04,039 Humanity's entire existence is a brief moment of brilliance Humanity's entire existence is a brief moment of brilliance
662 00:43:04,114 00:43:06,679 On this immense timeline. On this immense timeline.
663 00:43:06,754 00:43:09,719 And the stable environment we have relied on And the stable environment we have relied on
664 00:43:09,794 00:43:12,759 Will not last. Will not last.
665 00:43:12,834 00:43:15,632 Over earth's next few billion years, Over earth's next few billion years,
666 00:43:15,641 00:43:20,159 More ice ages, epic volcanic eruptions, More ice ages, epic volcanic eruptions,
667 00:43:20,201 00:43:24,039 Meteor impacts, and extinctions Meteor impacts, and extinctions
668 00:43:24,114 00:43:26,439 Will be inevitable. Will be inevitable.
669 00:43:26,514 00:43:30,752 ? ?
670 00:43:30,761 00:43:32,512 But the planet's history But the planet's history
671 00:43:32,521 00:43:36,759 Tells us some forms of life will survive. Tells us some forms of life will survive.
672 00:43:39,641 00:43:44,039 Where we fit into this future is up to us. Where we fit into this future is up to us.
673 00:43:44,114 00:43:56,879 ? ?