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, 3 00:00:08,914 --> 00:00:12,359 We've looked down on the marvels of our civilization. 4 00:00:16,121 --> 00:00:20,199 We've achieved incredible things, 5 00:00:20,274 --> 00:00:25,072 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 7 00:00:29,161 --> 00:00:32,352 Into how the dynamic life of our planet 8 00:00:32,361 --> 00:00:36,912 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 11 00:00:44,201 --> 00:00:49,632 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, 13 00:00:53,081 --> 00:00:56,519 They're our organ of adaptability. 14 00:00:56,594 --> 00:00:59,559 Narrator: We're revealing how a lifestyle revolution 15 00:00:59,634 --> 00:01:03,399 Triggered the growth of civilization. 16 00:01:03,474 --> 00:01:06,919 Man: These are probably the earliest ancient roadways 17 00:01:06,994 --> 00:01:09,199 In the world. 18 00:01:09,241 --> 00:01:12,839 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 20 00:01:16,514 --> 00:01:19,872 Hundreds of millions of years ago. 21 00:01:19,881 --> 00:01:21,639 Man: That's an energy revolution, 22 00:01:21,714 --> 00:01:26,199 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. 24 00:01:32,441 --> 00:01:35,632 Narrator: Humanity's very success is pushing us 25 00:01:35,641 --> 00:01:38,992 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 27 00:01:42,914 --> 00:01:46,119 In a billion years of earth history. 28 00:01:46,194 --> 00:01:49,199 Narrator: But our technology gives us a chance 29 00:01:49,241 --> 00:01:52,512 To shape what happens next. 30 00:01:52,521 --> 00:01:56,032 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. 32 00:01:58,514 --> 00:02:02,592 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, 35 00:02:16,194 --> 00:02:20,992 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, 39 00:02:40,601 --> 00:02:45,639 Planet earth has endured constant change-- 40 00:02:45,714 --> 00:02:51,312 Devastating impacts from asteroids and comets, 41 00:02:51,321 --> 00:02:53,399 And tectonic shifts generated 42 00:02:53,474 --> 00:02:56,912 By the churning heat beneath its crust, 43 00:02:56,921 --> 00:03:00,832 Transforming the planet's environment. 44 00:03:00,841 --> 00:03:03,239 All life that clings to its surface 45 00:03:03,314 --> 00:03:07,199 Evolves to survive 46 00:03:07,241 --> 00:03:09,639 Or succumbs to extinction. 47 00:03:13,081 --> 00:03:16,959 Our story begins 300,000 years ago. 48 00:03:19,314 --> 00:03:22,112 Earth's climate is colder than today, 49 00:03:22,121 --> 00:03:28,079 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, 51 00:03:32,281 --> 00:03:37,159 A new creature arises, 52 00:03:37,234 --> 00:03:41,319 A species of ape with great potential. 53 00:03:41,394 --> 00:03:44,119 They are us... 54 00:03:48,161 --> 00:03:49,879 Homo sapiens. 55 00:03:54,034 --> 00:03:56,599 But 300,000 years ago, 56 00:03:56,674 --> 00:03:58,999 We were not the only two-legged ape 57 00:03:59,074 --> 00:04:02,079 Wandering the african plains. 58 00:04:04,514 --> 00:04:07,639 2015, southern africa. 59 00:04:10,194 --> 00:04:13,559 In a region rich in ancient human fossils, 60 00:04:13,634 --> 00:04:19,759 A fantastic new discovery awaits deep underground. 61 00:04:21,474 --> 00:04:22,679 It's the first time 62 00:04:22,754 --> 00:04:25,639 Paleoanthropologist dr. Lee berger 63 00:04:25,714 --> 00:04:31,312 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 65 00:04:33,074 --> 00:04:34,999 Of almost 800 cave sites 66 00:04:35,074 --> 00:04:37,072 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. 68 00:04:42,114 --> 00:04:45,072 Narrator: Berger has heard rumors of human remains 69 00:04:45,081 --> 00:04:47,759 Glimpsed down one of these passageways. 70 00:04:51,154 --> 00:04:56,199 It's challenging terrain for the scientific team. 71 00:04:56,274 --> 00:04:57,472 Berger: To travel just 100 meters 72 00:04:57,481 --> 00:04:59,712 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 74 00:05:01,721 --> 00:05:04,512 At squeezing through very tight spaces. 75 00:05:04,521 --> 00:05:06,992 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. 78 00:05:17,394 --> 00:05:20,832 They make an incredible find. 79 00:05:20,841 --> 00:05:21,639 Berger: I was speechless. 80 00:05:21,714 --> 00:05:23,392 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. 82 00:05:26,361 --> 00:05:28,832 There was a clearly primitive hominid 83 00:05:28,841 --> 00:05:31,319 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. 86 00:05:41,081 --> 00:05:43,072 Berger and his team uncover bones 87 00:05:43,081 --> 00:05:46,032 From 15 separate skeletons, 88 00:05:46,041 --> 00:05:50,999 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, 90 00:05:54,914 --> 00:05:56,999 All the way to the extreme elderly, 91 00:05:57,074 --> 00:06:00,359 And everybody in between. 92 00:06:00,434 --> 00:06:03,239 Narrator: But the bones are not human. 93 00:06:05,881 --> 00:06:10,752 They belong to a totally new species-- 94 00:06:10,761 --> 00:06:12,439 Homo naledi. 95 00:06:15,074 --> 00:06:17,399 Berger: Imagine if you're standing out here 96 00:06:17,474 --> 00:06:21,239 300,000 years ago. 97 00:06:21,314 --> 00:06:24,319 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 99 00:06:28,434 --> 00:06:32,279 Because they're walking on two legs. 100 00:06:32,354 --> 00:06:33,959 As they approach, 101 00:06:34,034 --> 00:06:36,439 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, 103 00:06:38,594 --> 00:06:42,192 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, 105 00:06:45,874 --> 00:06:48,199 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. 107 00:06:52,434 --> 00:06:54,032 Narrator: Naledi now joined the ranks 108 00:06:54,041 --> 00:06:57,472 Of at least three other human-like species 109 00:06:57,481 --> 00:07:00,679 That existed in parallel to homo sapiens 110 00:07:00,754 --> 00:07:03,472 300,000 years ago, 111 00:07:03,481 --> 00:07:08,919 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 113 00:07:11,401 --> 00:07:16,159 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. 115 00:07:20,434 --> 00:07:24,272 Our evolutionary tree is branching and diverse, 116 00:07:24,281 --> 00:07:25,632 Like the evolutionary trees 117 00:07:25,641 --> 00:07:29,559 Of almost all other organisms on earth. 118 00:07:29,634 --> 00:07:32,079 Narrator: But if all these human-like competitors 119 00:07:32,121 --> 00:07:34,159 Once shared our planet, 120 00:07:34,201 --> 00:07:37,552 Why are we the only ones left? 121 00:07:37,561 --> 00:07:40,039 Potts: None of them now exist on earth. 122 00:07:40,201 --> 00:07:42,599 We are the last bipeds standing. 123 00:07:44,914 --> 00:07:47,952 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. 125 00:07:52,201 --> 00:07:59,559 ♪ 126 00:07:59,634 --> 00:08:02,999 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... 128 00:08:10,521 --> 00:08:15,479 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 130 00:08:18,601 --> 00:08:20,592 Throughout humanity's evolution, 131 00:08:20,601 --> 00:08:24,039 Periodic ice ages swing the african environment 132 00:08:24,114 --> 00:08:28,512 From wet to dry and back again. 133 00:08:28,521 --> 00:08:29,959 Potts: The past six million years 134 00:08:30,034 --> 00:08:32,032 Have been the most dramatic period 135 00:08:32,041 --> 00:08:35,232 Of climate oscillation and change in landscapes 136 00:08:35,241 --> 00:08:37,879 Ever since the extinction of the dinosaurs 137 00:08:37,954 --> 00:08:40,199 65 million years ago. 138 00:08:42,361 --> 00:08:44,199 Narrator: Any species that can't cope 139 00:08:44,274 --> 00:08:48,832 With rapid environmental change will not endure. 140 00:08:48,841 --> 00:08:53,472 Potts: The boundary between survival and extinction 141 00:08:53,481 --> 00:08:54,999 Was really adaptability, 142 00:08:55,074 --> 00:08:59,439 The ability to adjust to changes in the landscape. 143 00:09:01,721 --> 00:09:03,392 Narrator: Scientists think the need 144 00:09:03,401 --> 00:09:06,039 To solve environmental challenges 145 00:09:06,114 --> 00:09:11,119 Spurred homo sapiens to evolve a uniquely adaptive brain. 146 00:09:13,474 --> 00:09:16,432 We developed imagination and language skills 147 00:09:16,441 --> 00:09:18,679 Our rivals lacked. 148 00:09:21,081 --> 00:09:24,272 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. 150 00:09:27,081 --> 00:09:29,472 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, 152 00:09:34,114 --> 00:09:38,279 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 154 00:09:40,594 --> 00:09:42,839 What any other organism was capable of doing 155 00:09:42,914 --> 00:09:45,879 Up to that time, including earlier humans, 156 00:09:45,954 --> 00:09:50,039 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 158 00:09:55,001 --> 00:09:57,879 But also to accumulate. 159 00:09:57,954 --> 00:10:00,279 That was our real card 160 00:10:00,354 --> 00:10:03,472 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 163 00:10:11,074 --> 00:10:12,992 In a fluctuating climate, 164 00:10:13,001 --> 00:10:17,959 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 166 00:10:23,961 --> 00:10:25,599 Are overwhelmed. 167 00:10:28,114 --> 00:10:32,959 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 169 00:10:39,081 --> 00:10:42,439 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. 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 173 00:10:58,194 --> 00:11:00,999 That some of our ancestors now use 174 00:11:01,074 --> 00:11:03,439 To spread across the world. 175 00:11:07,241 --> 00:11:08,832 The decline and disappearance 176 00:11:08,841 --> 00:11:12,039 Of all remaining rival homo species 177 00:11:12,114 --> 00:11:15,239 Can be traced to this great migration. 178 00:11:18,121 --> 00:11:22,839 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 180 00:11:25,881 --> 00:11:30,279 Unlike any other animal before or since. 181 00:11:38,114 --> 00:11:41,919 The latest ice age approaches its peak. 182 00:11:47,154 --> 00:11:49,479 Over the last 30,000 years, 183 00:11:49,554 --> 00:11:56,192 Our ancestors have spread across the globe. 184 00:11:56,201 --> 00:12:00,192 But their path to the americas was hindered. 185 00:12:00,201 --> 00:12:05,952 Deep oceans proved a formidable obstruction, 186 00:12:05,961 --> 00:12:09,319 But now this barrier disappears. 187 00:12:09,394 --> 00:12:12,119 Expanding ice caps cause sea levels 188 00:12:12,194 --> 00:12:15,799 To dip to record lows. 189 00:12:15,874 --> 00:12:21,312 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. 191 00:12:25,394 --> 00:12:29,399 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. 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. 195 00:12:46,834 --> 00:12:53,472 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 197 00:12:55,554 --> 00:13:00,359 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 200 00:13:10,514 --> 00:13:13,072 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 203 00:13:21,634 --> 00:13:25,519 Of the deadly impact of this human migration. 204 00:13:28,754 --> 00:13:30,119 Dan fisher: What's that? 205 00:13:30,194 --> 00:13:31,879 There's something there. 206 00:13:31,954 --> 00:13:34,272 Okay, this shape right here 207 00:13:34,281 --> 00:13:37,959 Is the central column-like section of a vertebra, 208 00:13:38,034 --> 00:13:40,592 The part that supports weight. 209 00:13:40,601 --> 00:13:44,192 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... 211 00:13:50,834 --> 00:13:52,759 The woolly mammoth. 212 00:13:52,834 --> 00:13:54,759 Fisher: Humans living here at this time 213 00:13:54,834 --> 00:13:56,199 Would absolutely have encountered them 214 00:13:56,274 --> 00:14:00,432 On a more or less daily basis. 215 00:14:00,441 --> 00:14:02,039 Narrator: Before humans arrived, 216 00:14:02,114 --> 00:14:06,039 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. 218 00:14:16,274 --> 00:14:17,959 Fisher's evidence shows 219 00:14:18,034 --> 00:14:21,552 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 221 00:14:24,521 --> 00:14:26,512 That was cleaved off. 222 00:14:26,521 --> 00:14:28,512 This would suggest, not in a single piece, 223 00:14:28,521 --> 00:14:30,839 Maybe in multiple pieces, 224 00:14:30,914 --> 00:14:34,352 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 226 00:14:37,714 --> 00:14:40,359 To most easily remove the entire brain. 227 00:14:42,041 --> 00:14:44,112 Narrator: The early humans aren't just eating 228 00:14:44,121 --> 00:14:46,192 The nutritious brain. 229 00:14:46,201 --> 00:14:50,679 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 231 00:14:53,634 --> 00:14:55,639 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 233 00:14:59,801 --> 00:15:01,312 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, 235 00:15:05,394 --> 00:15:07,199 But then they'll eat them directly. 236 00:15:10,754 --> 00:15:14,079 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, 238 00:15:22,434 --> 00:15:26,832 Their numbers are in steep decline. 239 00:15:26,841 --> 00:15:30,519 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 241 00:15:35,561 --> 00:15:40,279 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. 243 00:15:44,201 --> 00:15:47,552 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 245 00:15:50,114 --> 00:15:52,039 On the population as a whole. 246 00:15:55,794 --> 00:15:58,912 The evidence strongly supports human activity 247 00:15:58,921 --> 00:16:03,519 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 249 00:16:09,401 --> 00:16:12,039 That as early as 10,000 years ago, 250 00:16:12,114 --> 00:16:15,872 Our adaptive brain gives us enormous influence 251 00:16:15,881 --> 00:16:17,639 Over our environment. 252 00:16:19,554 --> 00:16:22,352 But globally, our scattered populations 253 00:16:22,361 --> 00:16:25,519 Still total fewer than five million. 254 00:16:27,721 --> 00:16:30,359 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. 256 00:16:37,641 --> 00:16:40,839 But the planet itself will soon create opportunity 257 00:16:40,914 --> 00:16:43,472 For a new way of life. 258 00:16:43,481 --> 00:16:47,479 Humans will harness the power of cultivation, 259 00:16:47,554 --> 00:16:50,112 Transforming not just our population, 260 00:16:50,121 --> 00:16:54,919 But our societies, even the whole ecosystem. 261 00:17:03,394 --> 00:17:07,199 Our planet today is lit up by civilization. 262 00:17:15,161 --> 00:17:18,112 But 10,000 years ago, 263 00:17:18,121 --> 00:17:21,599 Not a single town or city exists. 264 00:17:25,074 --> 00:17:27,792 All humans are nomads. 265 00:17:27,801 --> 00:17:32,039 They live in small groups of hunter-gatherers, 266 00:17:32,121 --> 00:17:34,199 Always on the move, 267 00:17:34,274 --> 00:17:40,359 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. 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 271 00:17:55,314 --> 00:17:58,439 Alongside teeming cities, 272 00:17:58,514 --> 00:18:01,319 Hallmarks of civilization. 273 00:18:02,521 --> 00:18:04,832 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 276 00:18:11,394 --> 00:18:14,679 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, 278 00:18:24,681 --> 00:18:28,119 America launches a spy satellite program... 279 00:18:32,841 --> 00:18:35,599 Code name: Corona. 280 00:18:39,401 --> 00:18:42,919 For decades, the 800,000 satellite photographs 281 00:18:42,994 --> 00:18:48,119 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 283 00:18:53,074 --> 00:18:58,359 Persuades the government to declassify the images. 284 00:18:58,434 --> 00:19:00,199 This treasure trove of data 285 00:19:00,274 --> 00:19:04,799 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 287 00:19:12,994 --> 00:19:19,072 Studying corona spy photographs of the middle east. 288 00:19:19,081 --> 00:19:21,072 The images are invaluable 289 00:19:21,081 --> 00:19:24,359 Because 50 years ago when the photos were taken, 290 00:19:24,434 --> 00:19:28,512 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. 292 00:19:36,681 --> 00:19:38,359 Jesse casana: We were able to document 293 00:19:38,434 --> 00:19:42,839 Something like 10,000 previously unknown archaeological sites 294 00:19:42,914 --> 00:19:46,032 That, through the history of 150 years 295 00:19:46,041 --> 00:19:48,192 Of archaeologists working in the middle east, 296 00:19:48,201 --> 00:19:50,079 No one had ever documented. 297 00:19:51,721 --> 00:19:53,232 Narrator: In 2007, 298 00:19:53,241 --> 00:19:57,079 The spy images herald a breakthrough, 299 00:19:57,154 --> 00:19:59,872 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. 301 00:20:06,841 --> 00:20:10,992 4,000 years older than the pyramids of egypt, 302 00:20:11,001 --> 00:20:14,599 It's called tell brak. 303 00:20:14,674 --> 00:20:17,072 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 305 00:20:21,154 --> 00:20:24,279 That encompasses a very large area. 306 00:20:24,354 --> 00:20:26,759 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, 308 00:20:31,801 --> 00:20:37,079 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 310 00:20:40,674 --> 00:20:45,039 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. 312 00:20:53,121 --> 00:20:56,039 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. 315 00:21:11,394 --> 00:21:15,199 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. 317 00:21:18,681 --> 00:21:22,039 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, 320 00:21:30,201 --> 00:21:34,039 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. 323 00:21:47,954 --> 00:21:53,552 For millennia, humans foraged wild grass seeds, 324 00:21:53,561 --> 00:21:56,432 But now abundant wheat and barley 325 00:21:56,441 --> 00:21:59,679 Prove easy to grow and to control. 326 00:22:02,274 --> 00:22:04,359 Some people begin to settle, 327 00:22:04,434 --> 00:22:09,872 To nurture and protect their crops. 328 00:22:09,881 --> 00:22:13,399 They gradually give up the hunter-gatherer lifestyle 329 00:22:13,474 --> 00:22:18,352 To become farmers. 330 00:22:18,361 --> 00:22:20,079 From this point forward, 331 00:22:20,121 --> 00:22:25,072 Human reliance on cultivated plants and domesticated animals 332 00:22:25,121 --> 00:22:27,759 Will begin to change the landscape. 333 00:22:31,081 --> 00:22:34,592 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, 335 00:22:37,801 --> 00:22:41,399 Growing them, and rejecting all of the other plants around them, 336 00:22:41,474 --> 00:22:44,832 Simplifying those ecosystems. 337 00:22:44,841 --> 00:22:48,079 Narrator: Tell brak is special because the earliest evidence 338 00:22:48,121 --> 00:22:49,792 Of this shift to agriculture 339 00:22:49,801 --> 00:22:52,912 Is visible in the corona images-- 340 00:22:52,921 --> 00:22:55,319 The world's first roads. 341 00:22:55,394 --> 00:22:56,672 Casana: What we can see 342 00:22:56,681 --> 00:22:59,072 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. 344 00:23:03,481 --> 00:23:04,999 They're really long. 345 00:23:05,074 --> 00:23:08,512 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 347 00:23:12,354 --> 00:23:14,272 In the world. 348 00:23:14,281 --> 00:23:15,952 What we are able to reconstruct 349 00:23:15,961 --> 00:23:19,152 Is that, in the immediate hinterland surrounding the city, 350 00:23:19,161 --> 00:23:21,072 There would have been extensive fields 351 00:23:21,201 --> 00:23:25,392 Of intensively cultivated wheat and barley. 352 00:23:25,401 --> 00:23:27,159 The sheep and goat that lived with the people 353 00:23:27,234 --> 00:23:28,439 Here in tell brak, 354 00:23:28,514 --> 00:23:31,792 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, 356 00:23:33,161 --> 00:23:35,072 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. 358 00:23:37,234 --> 00:23:38,752 They served as passage 359 00:23:38,761 --> 00:23:41,479 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. 361 00:23:46,201 --> 00:23:49,392 Narrator: The settled populations expand, 362 00:23:49,401 --> 00:23:53,072 Overwhelming the remaining hunter-gatherers, 363 00:23:53,081 --> 00:23:56,079 Transforming the landscape 364 00:23:56,121 --> 00:24:01,079 With fields, villages, towns, 365 00:24:01,154 --> 00:24:05,152 And eventually cities. 366 00:24:05,161 --> 00:24:09,952 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. 368 00:24:16,914 --> 00:24:19,239 Over the next few thousand years, 369 00:24:19,314 --> 00:24:24,112 Agricultural revolutions occur across the globe. 370 00:24:24,121 --> 00:24:26,039 Each civilization is built 371 00:24:26,114 --> 00:24:31,152 Around locally cultivated plants. 372 00:24:31,161 --> 00:24:35,319 In china and southeast asia, rice and millet. 373 00:24:35,394 --> 00:24:38,839 In the americas, corn or potatoes. 374 00:24:41,721 --> 00:24:44,119 And wherever agriculture takes hold, 375 00:24:44,194 --> 00:24:48,352 There is a population explosion. 376 00:24:48,361 --> 00:24:50,359 By the first century a.D., 377 00:24:50,434 --> 00:24:55,392 The world population is over 170 million. 378 00:24:55,401 --> 00:24:59,159 By 1500, it's 500 million. 379 00:25:02,441 --> 00:25:05,632 The footprint of expanding human populations 380 00:25:05,641 --> 00:25:10,119 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 382 00:25:12,601 --> 00:25:15,079 On plants and animals for energy, 383 00:25:15,154 --> 00:25:18,599 Our growth is constrained. 384 00:25:21,481 --> 00:25:23,792 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. 386 00:25:34,274 --> 00:25:36,039 Above our heads today, 387 00:25:36,161 --> 00:25:39,559 Scores of satellites orbit the earth. 388 00:25:39,634 --> 00:25:42,999 Their mission--treasure seeking. 389 00:25:45,234 --> 00:25:49,872 Using an array of sensors, they probe the planet's surface, 390 00:25:49,881 --> 00:25:51,479 Seeking an energy bonanza 391 00:25:51,554 --> 00:25:54,759 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, 394 00:26:02,681 --> 00:26:06,519 It has experienced many violent transformations. 395 00:26:09,881 --> 00:26:11,199 But through them all, 396 00:26:11,241 --> 00:26:15,399 The sun has shone, bathing the surface with light, 397 00:26:15,474 --> 00:26:18,519 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, 400 00:26:26,594 --> 00:26:30,079 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 402 00:26:36,121 --> 00:26:42,079 In leaves, stems, and trunks. 403 00:26:42,121 --> 00:26:48,199 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. 405 00:26:53,154 --> 00:26:59,632 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 407 00:27:02,841 --> 00:27:08,032 In coal, oil, and gas, 408 00:27:08,041 --> 00:27:09,872 Which millions of years later 409 00:27:09,881 --> 00:27:13,952 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, 413 00:27:32,441 --> 00:27:34,432 To keep the fires burning, 414 00:27:34,441 --> 00:27:37,792 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, 417 00:27:48,281 --> 00:27:51,392 Populated areas like europe and china 418 00:27:51,401 --> 00:27:56,032 Burn up most of their forests. 419 00:27:56,041 --> 00:27:58,352 If they use up all their wood, 420 00:27:58,361 --> 00:28:01,719 Their civilizations may soon collapse. 421 00:28:06,194 --> 00:28:08,079 But in the 18th century, 422 00:28:08,121 --> 00:28:12,359 Humans tap the true potential of fossil fuels... 423 00:28:14,281 --> 00:28:16,272 Developing machines to harness 424 00:28:16,281 --> 00:28:19,559 This buried source of rich energy. 425 00:28:22,994 --> 00:28:24,912 Over just a few hundred years, 426 00:28:24,921 --> 00:28:28,999 They fuel humanity's great leap forward-- 427 00:28:29,074 --> 00:28:33,472 The industrial revolution. 428 00:28:33,481 --> 00:28:36,679 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, 430 00:28:40,274 --> 00:28:42,432 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 432 00:28:46,274 --> 00:28:47,312 That I, I think sometimes 433 00:28:47,321 --> 00:28:49,952 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 436 00:28:56,914 --> 00:29:00,479 Puts human civilization into overdrive. 437 00:29:02,761 --> 00:29:06,192 Wing: The energy revolution lets all of us 438 00:29:06,201 --> 00:29:10,112 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 440 00:29:15,161 --> 00:29:16,599 Is equivalent to having, 441 00:29:16,674 --> 00:29:19,519 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. 443 00:29:28,521 --> 00:29:32,639 Coal- and oil-powered ships link continents. 444 00:29:37,714 --> 00:29:41,719 Technological innovation allows instant communication 445 00:29:41,794 --> 00:29:44,272 Across the planet. 446 00:29:44,281 --> 00:29:48,079 Civilization is now truly global. 447 00:29:52,114 --> 00:29:53,552 But this energy revolution 448 00:29:53,561 --> 00:29:56,439 Also unleashes humanity's potential 449 00:29:56,514 --> 00:30:00,079 For incredible destructive power. 450 00:30:00,121 --> 00:30:05,799 [explosion] 451 00:30:05,874 --> 00:30:08,519 The explosion of the first atomic bomb 452 00:30:08,594 --> 00:30:11,679 Marks a turning point for humankind. 453 00:30:14,161 --> 00:30:18,959 [explosion] 454 00:30:21,001 --> 00:30:22,672 Over the following decades, 455 00:30:22,681 --> 00:30:26,512 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 458 00:30:36,361 --> 00:30:39,359 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, 460 00:30:44,914 --> 00:30:47,799 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. 462 00:30:53,081 --> 00:30:54,759 Narrator: This is the moment 463 00:30:54,834 --> 00:30:59,639 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 465 00:31:02,754 --> 00:31:06,839 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 467 00:31:16,514 --> 00:31:19,559 Has kept us from nuclear holocaust. 468 00:31:22,441 --> 00:31:24,039 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. 470 00:31:27,881 --> 00:31:35,559 ♪ 471 00:31:35,634 --> 00:31:38,759 It took humanity 300,000 years 472 00:31:38,834 --> 00:31:43,399 To reach a population of one billion. 473 00:31:43,474 --> 00:31:45,632 But in just two centuries, 474 00:31:45,641 --> 00:31:52,199 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, 476 00:31:55,801 --> 00:32:02,592 Over the entire habitable surface of the globe. 477 00:32:02,601 --> 00:32:04,039 Kirk johnson: During my life span, 478 00:32:04,121 --> 00:32:07,232 The population of the planet has more than doubled. 479 00:32:07,241 --> 00:32:08,992 The impact of that, of course, 480 00:32:09,001 --> 00:32:13,072 Is that people need food, land, iphones, 481 00:32:13,081 --> 00:32:15,359 Cars, buses, cities. 482 00:32:16,914 --> 00:32:20,512 So as humans grow, they're appropriating the natural world 483 00:32:20,521 --> 00:32:22,799 At a staggering rate. 484 00:32:24,594 --> 00:32:27,232 Narrator: It's estimated that to feed everyone, 485 00:32:27,241 --> 00:32:28,759 Farmers will need to produce 486 00:32:28,834 --> 00:32:31,479 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. 488 00:32:38,361 --> 00:32:41,559 But as we turn most of the globe to agriculture, 489 00:32:41,634 --> 00:32:44,879 We are destroying animal diversity. 490 00:32:47,314 --> 00:32:49,472 Today, livestock farming 491 00:32:49,481 --> 00:32:52,999 Covers a quarter of all available land. 492 00:32:56,754 --> 00:33:00,199 In just 50 years, wild mammal numbers 493 00:33:00,274 --> 00:33:03,519 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 495 00:33:08,601 --> 00:33:12,039 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. 497 00:33:13,721 --> 00:33:16,439 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 499 00:33:23,074 --> 00:33:25,039 Than ever measured before. 500 00:33:27,234 --> 00:33:29,392 Wing: How long are we going to continue 501 00:33:29,401 --> 00:33:33,559 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 503 00:33:37,074 --> 00:33:39,479 That we will end up in a mass extinction. 504 00:33:43,154 --> 00:33:44,432 Narrator: We may not notice 505 00:33:44,441 --> 00:33:48,199 The extinction of most wild animals, 506 00:33:48,274 --> 00:33:51,079 But our addiction to fossilized energy 507 00:33:51,154 --> 00:33:53,959 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 510 00:34:04,274 --> 00:34:06,799 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 512 00:34:14,681 --> 00:34:16,039 To reabsorb. 513 00:34:16,161 --> 00:34:19,792 ♪ 514 00:34:19,801 --> 00:34:24,039 [horns honking] 515 00:34:24,201 --> 00:34:26,439 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, 517 00:34:29,641 --> 00:34:34,672 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. 519 00:34:43,234 --> 00:34:44,839 Narrator: Measurements from space probes 520 00:34:44,914 --> 00:34:51,792 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 522 00:34:53,401 --> 00:34:54,839 By more than 40 percent. 523 00:34:54,914 --> 00:34:56,592 We've more than doubled the amount of methane, 524 00:34:56,601 --> 00:34:58,272 Another trace gas in the atmosphere. 525 00:34:58,281 --> 00:35:01,239 Each one of those things is changing the climate, 526 00:35:01,314 --> 00:35:02,599 Is changing the weather. 527 00:35:02,674 --> 00:35:04,512 Narrator: Earth's history tells us 528 00:35:04,521 --> 00:35:08,439 Rapid change in climate can be disastrous. 529 00:35:08,514 --> 00:35:11,159 Wing: We have past examples 530 00:35:11,234 --> 00:35:13,239 Where the amount of co2 has gone up 531 00:35:13,314 --> 00:35:15,159 And the earth's climate has warmed, 532 00:35:15,234 --> 00:35:18,519 So it's a fact. 533 00:35:18,594 --> 00:35:20,832 Narrator: 56 million years ago, 534 00:35:20,841 --> 00:35:24,432 The climate warmed nearly 14 degrees fahrenheit 535 00:35:24,441 --> 00:35:27,152 Over a few thousand years. 536 00:35:27,161 --> 00:35:29,879 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. 538 00:35:35,794 --> 00:35:37,072 But under our watch, 539 00:35:37,081 --> 00:35:42,512 The climate is changing at a much faster pace. 540 00:35:42,521 --> 00:35:44,199 In the last two centuries, 541 00:35:44,274 --> 00:35:48,352 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, 543 00:35:52,921 --> 00:35:54,752 And in just 50 years, 544 00:35:54,761 --> 00:35:59,792 Nearly half of our arctic ice has disappeared. 545 00:35:59,801 --> 00:36:04,352 We are creating a new planetary environment. 546 00:36:04,361 --> 00:36:06,192 Schmidt: We're pushing a system 547 00:36:06,201 --> 00:36:09,072 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, 549 00:36:10,681 --> 00:36:13,639 We have become a geological force 550 00:36:13,714 --> 00:36:16,752 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. 552 00:36:20,201 --> 00:36:23,119 Narrator: We face a calamity of our own making, 553 00:36:23,161 --> 00:36:25,239 But our species came this far 554 00:36:25,314 --> 00:36:29,792 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? 556 00:36:36,841 --> 00:36:40,272 The problems caused by humanity's great expansion 557 00:36:40,281 --> 00:36:43,399 Have been brewing for centuries. 558 00:36:43,474 --> 00:36:45,072 But scientists believe 559 00:36:45,201 --> 00:36:48,279 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. 561 00:36:52,514 --> 00:36:54,519 Potts: Humans are a turning point 562 00:36:54,594 --> 00:36:56,599 In the history of life on earth. 563 00:36:56,674 --> 00:36:58,352 We've become a global phenomenon 564 00:36:58,361 --> 00:37:00,839 And responsible for the intensity 565 00:37:00,914 --> 00:37:03,399 Of what is going on to our planet, 566 00:37:03,474 --> 00:37:04,992 To the ecosystems on which 567 00:37:05,001 --> 00:37:08,199 Not only other organisms, but human life depends. 568 00:37:08,274 --> 00:37:10,272 This is, in many ways, 569 00:37:10,281 --> 00:37:14,519 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, 571 00:37:19,161 --> 00:37:24,319 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. 573 00:37:34,834 --> 00:37:38,279 In the 1980s, above antarctica, 574 00:37:38,354 --> 00:37:41,479 Nasa satellites provide crucial confirmation 575 00:37:41,554 --> 00:37:46,032 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 577 00:37:49,474 --> 00:37:55,639 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, 579 00:37:57,881 --> 00:38:00,352 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, 581 00:38:02,041 --> 00:38:04,599 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 583 00:38:10,121 --> 00:38:12,039 Of globalized industry, 584 00:38:12,114 --> 00:38:15,072 Ozone-destroying man-made gases 585 00:38:15,081 --> 00:38:18,079 Used in aerosols and refrigeration. 586 00:38:20,441 --> 00:38:22,519 Spurred by the satellite evidence, 587 00:38:22,594 --> 00:38:27,119 Politicians around the world unite in action. 588 00:38:27,161 --> 00:38:29,392 Margaret thatcher: No one can opt out. 589 00:38:29,401 --> 00:38:31,559 Narrator: The chemicals are banned. 590 00:38:35,321 --> 00:38:36,679 Decades later, 591 00:38:36,754 --> 00:38:40,679 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. 593 00:38:45,081 --> 00:38:46,272 What would have happened? 594 00:38:46,281 --> 00:38:51,239 It would have reconfigured life on earth. 595 00:38:51,314 --> 00:38:54,839 Narrator: Space technology helped prevent disaster. 596 00:38:57,161 --> 00:38:58,439 Given the chance, 597 00:38:58,514 --> 00:39:02,359 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 599 00:39:12,514 --> 00:39:16,799 Also appear to show resilience in the age of humans. 600 00:39:20,114 --> 00:39:22,039 In downtown chicago, 601 00:39:22,201 --> 00:39:25,952 Dr. Stan gehrt uses gps technology 602 00:39:25,961 --> 00:39:29,239 To study a population of coyotes. 603 00:39:33,794 --> 00:39:35,232 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, 605 00:39:37,961 --> 00:39:40,039 But the satellites can pick them up. 606 00:39:42,441 --> 00:39:45,472 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. 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 610 00:39:59,794 --> 00:40:03,079 Can live in a major metropolitan area 611 00:40:03,154 --> 00:40:05,072 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. 613 00:40:12,361 --> 00:40:14,352 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 615 00:40:17,874 --> 00:40:21,319 With people not knowing that they're there. 616 00:40:21,394 --> 00:40:23,319 Narrator: They survive by adapting 617 00:40:23,394 --> 00:40:26,279 To the urban environment. 618 00:40:26,354 --> 00:40:28,199 Gehrt: Coyotes have to learn traffic patterns. 619 00:40:28,274 --> 00:40:30,079 They have to learn how to cross roads 620 00:40:30,121 --> 00:40:31,959 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, 622 00:40:36,121 --> 00:40:37,999 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 624 00:40:41,161 --> 00:40:42,839 With coyotes moving into the city 625 00:40:42,914 --> 00:40:46,272 Is being seen in virtually every single metropolitan area 626 00:40:46,281 --> 00:40:47,839 Across north america. 627 00:40:49,161 --> 00:40:52,992 [train horn blows] 628 00:40:53,001 --> 00:40:56,079 Narrator: If we can make space for nature, 629 00:40:56,121 --> 00:40:59,119 It can survive alongside us. 630 00:41:05,234 --> 00:41:06,839 Satellites can also provide 631 00:41:06,914 --> 00:41:10,159 A path to preserving animal diversity. 632 00:41:12,274 --> 00:41:14,119 Radio-tagging technology 633 00:41:14,194 --> 00:41:17,799 Allows the mapping of wildlife migration routes 634 00:41:17,874 --> 00:41:20,759 Thousands of miles long, 635 00:41:20,834 --> 00:41:24,039 Maps we can use to create protected corridors 636 00:41:24,201 --> 00:41:28,832 To save species from human interference. 637 00:41:28,841 --> 00:41:30,352 It's just one example 638 00:41:30,361 --> 00:41:35,632 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, 640 00:41:37,794 --> 00:41:40,352 When we as humans have technology, 641 00:41:40,361 --> 00:41:42,119 We have the ability to plan ahead, 642 00:41:42,194 --> 00:41:44,592 We know our geologic past. 643 00:41:44,601 --> 00:41:46,032 We can put all that together 644 00:41:46,041 --> 00:41:49,232 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. 646 00:41:51,714 --> 00:41:56,039 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, 649 00:42:01,641 --> 00:42:05,072 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... 652 00:42:18,201 --> 00:42:21,392 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 655 00:42:31,314 --> 00:42:34,319 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. 657 00:42:43,474 --> 00:42:46,759 For the last 4.5 billion years, 658 00:42:46,834 --> 00:42:50,672 It has experienced monumental change. 659 00:42:50,681 --> 00:42:54,439 Species that dominate then disappear, 660 00:42:54,514 --> 00:42:59,072 Giving rise to new life. 661 00:42:59,081 --> 00:43:04,039 Humanity's entire existence is a brief moment of brilliance 662 00:43:04,114 --> 00:43:06,679 On this immense timeline. 663 00:43:06,754 --> 00:43:09,719 And the stable environment we have relied on 664 00:43:09,794 --> 00:43:12,759 Will not last. 665 00:43:12,834 --> 00:43:15,632 Over earth's next few billion years, 666 00:43:15,641 --> 00:43:20,159 More ice ages, epic volcanic eruptions, 667 00:43:20,201 --> 00:43:24,039 Meteor impacts, and extinctions 668 00:43:24,114 --> 00:43:26,439 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 671 00:43:32,521 --> 00:43:36,759 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. 673 00:43:44,114 --> 00:43:56,879 ♪