1 00:00:00,454 --> 00:00:01,919 [music playing] 2 00:00:08,467 --> 00:00:11,472 Narrator: Before humans even walked the earth, 3 00:00:11,507 --> 00:00:14,512 The forces of nature shaped our world. 4 00:00:14,547 --> 00:00:21,072 Ours is the blue planet, bathed in water and teeming with life. 5 00:00:21,147 --> 00:00:24,912 [music playing] 6 00:00:24,947 --> 00:00:29,479 Without water, plants, animals, and the human race 7 00:00:29,554 --> 00:00:30,519 Would not exist. 8 00:00:34,147 --> 00:00:36,959 Early civilizations are drawn to the water. 9 00:00:43,187 --> 00:00:44,879 They settle along rivers, 10 00:00:48,787 --> 00:00:51,432 Making bricks from water and earth 11 00:00:51,507 --> 00:00:52,879 To build their homes. 12 00:00:56,147 --> 00:01:00,032 As societies grow, the use and distribution of water 13 00:01:00,107 --> 00:01:03,239 Become a driving force in state building. 14 00:01:03,927 --> 00:01:09,639 Settlements by the sea grow into cities of wealth and beauty. 15 00:01:09,714 --> 00:01:12,999 They become symbols of progress and prosperity 16 00:01:13,074 --> 00:01:15,392 Around the world. 17 00:01:15,427 --> 00:01:18,272 We've even built cities in the desert, 18 00:01:18,347 --> 00:01:22,072 A feat made possible only by bringing in water 19 00:01:22,147 --> 00:01:24,479 From hundreds of miles away. 20 00:01:25,874 --> 00:01:30,832 We're drawn to water and instinctively love the sounds 21 00:01:30,867 --> 00:01:35,472 And smells of the sea, perhaps because our bodies 22 00:01:35,481 --> 00:01:39,799 Themselves are 60% water. 23 00:01:39,874 --> 00:01:43,632 Yet as our population has exploded across the globe, 24 00:01:43,667 --> 00:01:46,912 We've put earth's water in danger. 25 00:01:46,947 --> 00:01:50,519 We're living in what some scientists call the age 26 00:01:50,594 --> 00:01:55,632 Of humans, a time when our impact is the defining force 27 00:01:55,667 --> 00:01:57,479 That's shaping planet earth. 28 00:02:00,547 --> 00:02:05,872 From glaciers to aquifers, shallow reefs to deep seas, 29 00:02:05,907 --> 00:02:09,112 We are putting more stress on earth's water 30 00:02:09,187 --> 00:02:12,672 Than at any other time in history. 31 00:02:12,707 --> 00:02:18,112 Human ambition and ingenuity are how we got here and may also 32 00:02:18,147 --> 00:02:23,392 Be how we reverse the damage and guarantee clean water on 33 00:02:23,467 --> 00:02:26,999 Our blue planet in the future. 34 00:02:27,074 --> 00:02:29,679 [music playing] 35 00:02:46,227 --> 00:02:50,672 Water covers 70% of the earth's surface. 36 00:02:50,707 --> 00:02:55,472 It's all around us in many forms, from rain and clouds 37 00:02:55,481 --> 00:02:57,872 To snow and ice. 38 00:02:57,947 --> 00:03:01,952 The overall amount of water on earth never changes. 39 00:03:01,987 --> 00:03:06,192 It merely shape shifts from one form to another 40 00:03:06,227 --> 00:03:12,832 To exist in every corner of land, sea, and sky. 41 00:03:12,867 --> 00:03:15,632 It circulates from the air to the ground 42 00:03:15,667 --> 00:03:20,632 And then through plants, animals, even ourselves. 43 00:03:20,707 --> 00:03:22,919 It never truly dries up. 44 00:03:27,001 --> 00:03:32,112 The heat of the sun makes water evaporate and form clouds. 45 00:03:32,147 --> 00:03:37,159 As clouds cool off, they produce rain since cold air stores 46 00:03:37,234 --> 00:03:41,752 Less water than warm air, and then rainwater on earth 47 00:03:41,827 --> 00:03:45,159 Is used by plants and animals. 48 00:03:45,234 --> 00:03:50,672 This is the water cycle, and it never stops. 49 00:03:50,681 --> 00:03:53,719 [music playing] 50 00:03:56,987 --> 00:04:00,072 The immense rainforests of the amazon basin 51 00:04:00,147 --> 00:04:04,152 Are about the size of america's lower 48 states. 52 00:04:04,227 --> 00:04:09,072 What water does here is a fascinating story. 53 00:04:09,107 --> 00:04:13,959 In 2017, it was discovered that trees in the amazon 54 00:04:14,034 --> 00:04:17,712 Release enough moisture through photosynthesis 55 00:04:17,747 --> 00:04:20,832 To create low-level clouds. 56 00:04:20,867 --> 00:04:24,879 In other words, the forest makes its own rain. 57 00:04:29,267 --> 00:04:33,072 Around the world, trees keep moisture in place. 58 00:04:33,147 --> 00:04:36,032 Without them, water would escape into the air 59 00:04:36,067 --> 00:04:39,072 And to lakes, rivers, and oceans. 60 00:04:39,107 --> 00:04:42,592 The overall amount of water on the planet remains constant-- 61 00:04:42,627 --> 00:04:47,752 About 330 million cubic miles. 62 00:04:47,827 --> 00:04:50,352 [speaking german] 63 00:04:50,387 --> 00:04:51,872 Interpreter: There's ample water on earth. 64 00:04:51,907 --> 00:04:54,112 Most of it is saltwater. 65 00:04:54,147 --> 00:04:56,592 If we put all the water into a liter bottle, 66 00:04:56,667 --> 00:05:01,159 Then just a few sips, about an ounce, would be freshwater. 67 00:05:01,234 --> 00:05:03,872 And most of that would be ice or snow. 68 00:05:03,907 --> 00:05:05,639 So we have very little freshwater 69 00:05:05,714 --> 00:05:06,799 Available for all living beings. 70 00:05:11,987 --> 00:05:13,712 Narrator: Part of earth's freshwater 71 00:05:13,747 --> 00:05:17,872 Is stored in aquifers, water-containing layers of rock 72 00:05:17,907 --> 00:05:20,912 Up to three miles below the surface. 73 00:05:20,947 --> 00:05:23,792 This so-called fossil water has been there 74 00:05:23,827 --> 00:05:26,632 For thousands, even millions of years, 75 00:05:26,707 --> 00:05:29,232 And renews itself very slowly. 76 00:05:29,267 --> 00:05:33,712 Mostly hidden to ancient humans, modern technology makes 77 00:05:33,747 --> 00:05:36,032 That water accessible today. 78 00:05:36,107 --> 00:05:40,832 In the 1970s, groundwater made it possible for saudi arabia 79 00:05:40,867 --> 00:05:45,159 To become one of the biggest wheat exporters in the world. 80 00:05:45,234 --> 00:05:47,952 But in the space of a couple generations, 81 00:05:47,961 --> 00:05:50,432 The country depleted its aquifers, 82 00:05:50,467 --> 00:05:55,072 And today, they're almost empty. 83 00:05:55,147 --> 00:05:58,992 Groundwater also gives life to the mar de plastico, 84 00:05:59,001 --> 00:06:01,592 The world's largest plastic greenhouse 85 00:06:01,667 --> 00:06:04,112 Complex in southern Spain. 86 00:06:04,187 --> 00:06:08,839 The buildings here span 134 square miles, 87 00:06:08,914 --> 00:06:11,639 So massive that they're visible from space. 88 00:06:14,147 --> 00:06:16,832 It's been called europe's largest winter 89 00:06:16,867 --> 00:06:19,632 Garden, providing about 3 million 90 00:06:19,667 --> 00:06:23,232 Tons of greenhouse vegetables. 91 00:06:23,267 --> 00:06:26,752 Groundwater from northern Spain makes it possible. 92 00:06:26,827 --> 00:06:30,239 But here too, the supply is almost gone. 93 00:06:34,387 --> 00:06:37,632 Consumption of water per capita varies greatly 94 00:06:37,667 --> 00:06:39,232 From country to country. 95 00:06:39,267 --> 00:06:41,072 In large parts of africa, 96 00:06:41,107 --> 00:06:42,672 For example, 97 00:06:42,707 --> 00:06:46,999 It's considerably lower than in most industrialized countries. 98 00:06:49,987 --> 00:06:53,392 Not surprisingly, the world's megacities consume 99 00:06:53,427 --> 00:06:56,152 Water on a massive scale. 100 00:06:56,227 --> 00:07:00,032 In new york city, 8.3 million residents 101 00:07:00,067 --> 00:07:02,752 Use a staggering 1 billion gallons 102 00:07:02,827 --> 00:07:05,952 Of fresh water every day. 103 00:07:05,987 --> 00:07:08,959 It comes to them from upstate reservoirs. 104 00:07:14,067 --> 00:07:17,952 The new croton dam, 22 miles north of the city, 105 00:07:17,987 --> 00:07:21,159 Was built in the early 1900s to increase 106 00:07:21,234 --> 00:07:25,232 The water supply for a rapidly growing population. 107 00:07:25,267 --> 00:07:29,072 At the time, it's the tallest dam in the world, 108 00:07:29,107 --> 00:07:32,072 A masterpiece of engineering. 109 00:07:32,147 --> 00:07:34,192 The water is carried by aqueducts 110 00:07:34,227 --> 00:07:38,832 To huge reservoirs in the city. 111 00:07:38,867 --> 00:07:41,272 Today, the new york city water system 112 00:07:41,347 --> 00:07:46,199 Is a massive infrastructure, 6,800 miles of iron 113 00:07:46,274 --> 00:07:50,272 And steel pipes stretching beneath the city. 114 00:07:50,307 --> 00:07:54,072 From its sources, water reaches the sixth floor of buildings 115 00:07:54,147 --> 00:07:57,232 By natural pressure alone. 116 00:07:57,267 --> 00:08:00,039 And the quality of the water is famously pure. 117 00:08:03,987 --> 00:08:06,952 But back in the middle ages, water quality 118 00:08:07,027 --> 00:08:10,192 Was an undiscovered science. 119 00:08:10,227 --> 00:08:13,152 Men carried drinking water from public wells, 120 00:08:13,187 --> 00:08:15,959 Delivering it directly to the people. 121 00:08:16,034 --> 00:08:18,832 No one knows that the water they need for life 122 00:08:18,867 --> 00:08:22,752 Can actually make them sick. 123 00:08:22,787 --> 00:08:23,839 [speaking german] 124 00:08:25,874 --> 00:08:27,552 Interpreter: During the middle ages, 125 00:08:27,587 --> 00:08:31,479 People had no idea of the actual origins of diseases. 126 00:08:31,554 --> 00:08:35,319 They suspected parasites or the so-called miasma, 127 00:08:35,394 --> 00:08:39,792 Polluted air which contained and transported germs. 128 00:08:39,827 --> 00:08:42,912 There was a general notion that something within these fumes 129 00:08:42,947 --> 00:08:44,472 Caused illnesses. 130 00:08:44,547 --> 00:08:46,999 However, they didn't yet know what this was. 131 00:08:51,267 --> 00:08:53,232 Narrator: By the 17th century, it 132 00:08:53,267 --> 00:08:55,232 Becomes possible to discern what's hidden 133 00:08:55,307 --> 00:08:57,432 In a single drop of water. 134 00:08:57,507 --> 00:09:00,512 A lens grinder by the name of antonie van leeuwenhoek 135 00:09:00,547 --> 00:09:03,792 Creates a microscope that can magnify an object 136 00:09:03,827 --> 00:09:07,472 By 270 times its original size. 137 00:09:07,507 --> 00:09:11,152 Among other things, he discovers bacteria, though he doesn't 138 00:09:11,187 --> 00:09:13,472 Yet understand its importance. 139 00:09:13,507 --> 00:09:16,039 [music playing] 140 00:09:19,987 --> 00:09:24,832 By the late 1800s, waterborne diseases plague european cities 141 00:09:24,841 --> 00:09:26,592 On a regular basis. 142 00:09:26,627 --> 00:09:30,992 In hamburg, germany, the city's last cholera outbreak 143 00:09:31,027 --> 00:09:33,472 Kills almost 9,000 people who have been 144 00:09:33,507 --> 00:09:37,472 Drinking polluted river water. 145 00:09:37,481 --> 00:09:39,959 [speaking german] 146 00:09:40,034 --> 00:09:42,032 Interpreter: In hamburg, there's an additional problem. 147 00:09:42,067 --> 00:09:45,952 The ebb tides of the elbe river may take the sewage with them. 148 00:09:45,987 --> 00:09:49,479 At high tide, however, they are pressed back into the canals, 149 00:09:49,554 --> 00:09:52,992 So the dirt gets stuck and causes bacterial pollution, 150 00:09:53,027 --> 00:09:54,279 Which in turn causes cholera. 151 00:10:00,667 --> 00:10:04,672 Narrator: Robert koch is a world-famous bacteriologist who 152 00:10:04,707 --> 00:10:08,032 Finds humburg's living conditions to be appalling, 153 00:10:08,067 --> 00:10:10,632 Even for the time. 154 00:10:10,707 --> 00:10:15,392 He identifies that water is the key to stopping the outbreak. 155 00:10:15,427 --> 00:10:17,952 And this motivates local government 156 00:10:17,987 --> 00:10:22,112 To install filtration systems for the first time. 157 00:10:22,187 --> 00:10:24,479 [music playing] 158 00:10:29,074 --> 00:10:34,512 In 2010, access to clean water is recognized as a human right 159 00:10:34,547 --> 00:10:37,472 By the assembly of the united nations. 160 00:10:37,507 --> 00:10:42,352 But even today, it's not always available around the world. 161 00:10:42,387 --> 00:10:45,152 We'll need more and more technology 162 00:10:45,187 --> 00:10:49,312 To make that right a reality. 163 00:10:49,321 --> 00:10:53,152 Desalination is one that holds promise-- 164 00:10:53,187 --> 00:10:56,679 The process of making saltwater into fresh. 165 00:10:56,754 --> 00:10:59,319 [music playing] 166 00:11:05,507 --> 00:11:08,512 At this plant in carlsbad, california, 167 00:11:08,547 --> 00:11:13,432 Desalinated seawater supplies 300,000 homes. 168 00:11:13,507 --> 00:11:19,072 It's done using high pressure and fine-poured membranes. 169 00:11:19,107 --> 00:11:25,072 Water purification is another process in widespread use. 170 00:11:25,147 --> 00:11:28,112 In a suburb of los angeles, sewage water 171 00:11:28,147 --> 00:11:34,199 Is purified in several stages, first by microfiltration 172 00:11:34,274 --> 00:11:37,712 Followed by reverse osmosis and disinfection 173 00:11:37,747 --> 00:11:41,232 By ultraviolet light. 174 00:11:41,267 --> 00:11:44,472 More technologies like these are key to meeting 175 00:11:44,547 --> 00:11:47,272 The needs of the world's growing population, 176 00:11:47,347 --> 00:11:49,159 And we're not there yet. 177 00:11:51,667 --> 00:11:54,752 Today, more than 2 billion people do 178 00:11:54,787 --> 00:11:57,432 Not have access to clean water. 179 00:11:57,507 --> 00:12:01,159 It's particularly limited in parts of asia and africa. 180 00:12:04,707 --> 00:12:09,792 A big threat to water around the world is, of course, pollution. 181 00:12:09,827 --> 00:12:13,279 Its effects are easily measured in the waters off big cities. 182 00:12:18,707 --> 00:12:22,999 In new york, only a handful of traditional fishing boats 183 00:12:23,074 --> 00:12:24,199 Still ply the harbors. 184 00:12:27,267 --> 00:12:29,079 They're the last of their kind. 185 00:12:31,827 --> 00:12:36,199 In decades past, the hudson river was a rich and productive 186 00:12:36,274 --> 00:12:40,072 Marine ecosystem, thanks in part to millions 187 00:12:40,147 --> 00:12:44,272 Of oysters that helped to keep the waters clean. 188 00:12:44,307 --> 00:12:49,639 Today, almost all the oysters are gone due to overfishing 189 00:12:49,714 --> 00:12:51,232 And pollution. 190 00:12:51,267 --> 00:12:53,392 But a group of conservationists is 191 00:12:53,467 --> 00:12:56,679 Working to turn back the clock. 192 00:12:56,754 --> 00:13:00,312 Their goal is to bring back a billion 193 00:13:00,387 --> 00:13:04,312 Live oysters to these waters. 194 00:13:04,387 --> 00:13:06,192 New york harbor used to be full of oysters, 195 00:13:06,227 --> 00:13:08,072 200,000 acres of oyster reef. 196 00:13:08,147 --> 00:13:10,432 It was the dominant habitat type in the harbor. 197 00:13:10,507 --> 00:13:12,832 And back at that time, 500 years ago, 198 00:13:12,867 --> 00:13:15,712 The harbor was also full of fish and other marine life. 199 00:13:15,747 --> 00:13:20,032 And the oysters are the keystone species in that ecosystem. 200 00:13:20,107 --> 00:13:22,432 So when europeans first arrived in new york harbor, 201 00:13:22,467 --> 00:13:23,872 There were so many fish that you could catch them 202 00:13:23,907 --> 00:13:26,072 Just by lowering a basket over the side of the boat 203 00:13:26,147 --> 00:13:27,712 And pulling it back up. 204 00:13:27,747 --> 00:13:31,712 So the harbor is actually literally full of live animals. 205 00:13:31,747 --> 00:13:33,792 Narrator: Oysters are remarkable filter 206 00:13:33,801 --> 00:13:38,192 Feeders that act like living sewage treatment plants. 207 00:13:38,227 --> 00:13:43,792 A single oyster can filter 60 gallons of water every day. 208 00:13:43,827 --> 00:13:47,392 Along with clams and shellfish, they also 209 00:13:47,427 --> 00:13:50,432 Remove excess nitrogen that they use to grow 210 00:13:50,467 --> 00:13:53,479 Their shells and tissue. 211 00:13:53,554 --> 00:13:57,112 The billion oyster project collects oyster shells 212 00:13:57,187 --> 00:13:59,472 From local restaurants and plants 213 00:13:59,507 --> 00:14:03,272 Them in floating cages on artificial reefs. 214 00:14:03,347 --> 00:14:06,519 If all goes as planned, oyster larvae 215 00:14:06,594 --> 00:14:11,112 Will nest on these old shells and reproduce. 216 00:14:11,187 --> 00:14:12,752 We hope that by restoring oyster reefs, 217 00:14:12,827 --> 00:14:16,192 We can return those ecosystem functions, the services that 218 00:14:16,227 --> 00:14:17,392 They provided traditionally. 219 00:14:17,427 --> 00:14:19,072 The oysters filter the water. 220 00:14:19,107 --> 00:14:21,312 They provide food and habitat for thousands of animals. 221 00:14:21,347 --> 00:14:22,839 They stabilize the bottom. 222 00:14:22,914 --> 00:14:25,872 And they can protect the shore from storm 223 00:14:25,907 --> 00:14:27,712 Events and wave action. 224 00:14:27,747 --> 00:14:29,712 Narrator: If this project succeeds, 225 00:14:29,747 --> 00:14:33,112 Then the tiny oyster will return to its role 226 00:14:33,187 --> 00:14:35,472 As protector of a megacity. 227 00:14:35,507 --> 00:14:37,432 It's one solution. 228 00:14:37,507 --> 00:14:40,639 But in the age of humans, we'll need many more. 229 00:14:44,227 --> 00:14:48,312 Throughout the age of humans, people have found myriad ways 230 00:14:48,387 --> 00:14:51,392 To use water in all its forms. 231 00:14:51,427 --> 00:14:54,192 Harnessing the power of water for energy 232 00:14:54,227 --> 00:14:57,639 Opens a world of possibilities. 233 00:14:57,714 --> 00:15:02,152 300 years ago in the upper harz mountains of germany, 234 00:15:02,227 --> 00:15:05,952 Residents reshaped land across 80 square miles 235 00:15:05,987 --> 00:15:08,752 To support local silver mines. 236 00:15:08,827 --> 00:15:13,632 Both above and below ground lies an immense, sophisticated 237 00:15:13,667 --> 00:15:17,632 System of dams, ditches, tunnels, and canals 238 00:15:17,667 --> 00:15:20,672 That's unique in the world. 239 00:15:20,707 --> 00:15:25,472 It's preserved today as a unesco world heritage site. 240 00:15:25,507 --> 00:15:28,832 Interpreter: This is groundwater that's coming in here. 241 00:15:28,867 --> 00:15:32,272 The amount is practically the same in summer as in winter-- 242 00:15:32,307 --> 00:15:34,472 Almost 80 gallons a minute. 243 00:15:34,547 --> 00:15:37,479 That's roughly 100,000 gallons a day. 244 00:15:42,387 --> 00:15:47,472 Narrator: In the 1700s, silver is mined here in deep shafts, 245 00:15:47,507 --> 00:15:50,632 But groundwater gets in the way. 246 00:15:50,707 --> 00:15:55,312 At first, it's removed by hand, a slow and backbreaking 247 00:15:55,347 --> 00:15:59,632 Process, until engineers make an ingenious discovery 248 00:15:59,667 --> 00:16:02,399 And turn that water into power. 249 00:16:05,827 --> 00:16:09,472 They install wheels which drive mechanical pumps, 250 00:16:09,507 --> 00:16:11,399 Creating hydraulic energy. 251 00:16:17,554 --> 00:16:18,759 [speaking german] 252 00:16:20,547 --> 00:16:21,872 Interpreter: This is called a reversible wheel. 253 00:16:21,907 --> 00:16:23,552 It's a water wheel that can switch 254 00:16:23,627 --> 00:16:25,799 Its direction of rotation. 255 00:16:25,874 --> 00:16:27,792 A rope is wound up. 256 00:16:27,827 --> 00:16:30,672 The pit cage is drawn upwards, while at the same time, 257 00:16:30,681 --> 00:16:33,639 A second rope uncoils, and the other cage goes downward. 258 00:16:36,507 --> 00:16:38,359 Narrator: The water wheel helps this region 259 00:16:38,434 --> 00:16:42,992 Become the biggest mining area of germany in the 18th century. 260 00:16:43,027 --> 00:16:45,479 [music playing] 261 00:16:48,547 --> 00:16:51,392 Elsewhere in the world, people are experimenting 262 00:16:51,427 --> 00:16:55,319 With more ways to harness the power of water in its form 263 00:16:55,394 --> 00:16:58,032 As vapor. 264 00:16:58,067 --> 00:17:01,592 Steam power has been known about since ancient times. 265 00:17:01,667 --> 00:17:04,792 In the late 1600s, a frenchmen named 266 00:17:04,867 --> 00:17:08,032 Denis papin discovers that steam can 267 00:17:08,067 --> 00:17:11,392 Be used to speed up cooking. 268 00:17:11,427 --> 00:17:13,792 He experiments with a pressure cooker, 269 00:17:13,827 --> 00:17:16,439 A process of trial and error. 270 00:17:22,147 --> 00:17:26,839 Only when papin inserts a safety valve does his invention work. 271 00:17:29,714 --> 00:17:33,552 Papin's valve opens up new possibilities. 272 00:17:33,627 --> 00:17:36,032 Steam engines and turbines are the driving 273 00:17:36,067 --> 00:17:41,712 Force of the industrial age, but progress often comes at a cost. 274 00:17:41,747 --> 00:17:44,592 Steam power requires huge amounts of energy 275 00:17:44,627 --> 00:17:47,072 To produce, typically from power plants 276 00:17:47,107 --> 00:17:48,992 Running on fossil fuels-- 277 00:17:49,027 --> 00:17:51,639 Coal, oil, and gas. 278 00:17:51,714 --> 00:17:55,112 Polluting the air and feeding the greenhouse effect, 279 00:17:55,187 --> 00:17:58,679 The legacy of these fuels is being felt around the globe. 280 00:18:02,387 --> 00:18:07,072 Melting glaciers are among the most alarming legacies. 281 00:18:07,107 --> 00:18:12,792 Since 1961, glaciers have lost billions of tons of ice, 282 00:18:12,867 --> 00:18:16,832 Contributing to rising sea levels around the world. 283 00:18:16,867 --> 00:18:20,032 Sea level will rise, and what this will do 284 00:18:20,067 --> 00:18:24,472 Is it will absolutely undermine agricultural productivity 285 00:18:24,547 --> 00:18:26,152 In most parts of the world. 286 00:18:26,227 --> 00:18:30,752 It will adversely affect water quantity and quality. 287 00:18:30,787 --> 00:18:33,639 It will affect our natural ecosystems. 288 00:18:33,714 --> 00:18:35,872 It will displace millions and tens 289 00:18:35,907 --> 00:18:38,632 Of millions of people who live in small island 290 00:18:38,707 --> 00:18:41,872 States, deltaic areas. 291 00:18:41,907 --> 00:18:45,472 Deltaic areas are also called wetlands, 292 00:18:45,507 --> 00:18:49,479 Like the florida everglades, home to a unique variety 293 00:18:49,554 --> 00:18:51,872 Of plants and animals. 294 00:18:51,907 --> 00:18:56,679 A staggering 85% of all wetland areas on earth 295 00:18:56,754 --> 00:18:59,112 Have already vanished. 296 00:18:59,187 --> 00:19:02,519 In the united states, the everglades are already feeling 297 00:19:02,594 --> 00:19:05,959 The effects of sea level rise. 298 00:19:06,034 --> 00:19:09,552 Water throughout the state has been dammed and diverted 299 00:19:09,627 --> 00:19:13,952 By humans since the middle of the last century, 300 00:19:13,987 --> 00:19:17,432 And more and more groundwater is needed to support 301 00:19:17,507 --> 00:19:20,152 An ever-growing population. 302 00:19:20,227 --> 00:19:22,432 Now there's an added pressure. 303 00:19:22,507 --> 00:19:26,832 Sea water is pushing inland, and the freshwater everglades 304 00:19:26,867 --> 00:19:29,952 Are being invaded by saltwater. 305 00:19:29,987 --> 00:19:33,152 The everglades is the aquifer replenishment 306 00:19:33,161 --> 00:19:35,479 Zone for all of south florida. 307 00:19:35,554 --> 00:19:37,632 We rely on one main aquifer. 308 00:19:37,667 --> 00:19:40,032 That's the biscayne aquifer. 309 00:19:40,107 --> 00:19:43,792 The biscayne aquifer, however, has become inundated, 310 00:19:43,801 --> 00:19:47,552 Year after year, during the spring king tides. 311 00:19:47,587 --> 00:19:50,199 When that happens, miami beach the last several years 312 00:19:50,274 --> 00:19:54,632 Has been underwater, under saltwater, because of how 313 00:19:54,707 --> 00:19:55,872 High the king tides have been. 314 00:19:55,907 --> 00:19:58,199 When that happens, that saltwater 315 00:19:58,274 --> 00:20:01,952 Has to trickle down through the substrate and into the aquifer. 316 00:20:01,961 --> 00:20:05,232 What connects the everglades to the ocean 317 00:20:05,307 --> 00:20:08,112 Is the aquifer under the ground. 318 00:20:08,147 --> 00:20:11,712 When the sea level rises and the everglades does not come up 319 00:20:11,747 --> 00:20:14,512 Equivalently, saltwater comes underneath 320 00:20:14,547 --> 00:20:15,952 And infiltrates our aquifer. 321 00:20:15,987 --> 00:20:18,752 [music playing] 322 00:20:18,827 --> 00:20:20,672 Narrator: Freshwater plants and animals 323 00:20:20,707 --> 00:20:23,312 Can't survive in saltwater. 324 00:20:23,347 --> 00:20:26,672 And that's not the only harm being caused by rising seas. 325 00:20:26,707 --> 00:20:30,519 [music playing] 326 00:20:30,594 --> 00:20:36,272 All around the world, oceans are eating away at the coastline. 327 00:20:36,347 --> 00:20:40,832 In the united states alone, real estate worth $500 million 328 00:20:40,867 --> 00:20:44,112 Has been lost to erosion. 329 00:20:44,147 --> 00:20:48,752 Countermeasures have had only limited success. 330 00:20:48,787 --> 00:20:55,072 Two thirds of all beaches in southern california are doomed. 331 00:20:55,107 --> 00:20:58,719 Coastal cities are facing submersion all over the world. 332 00:21:02,707 --> 00:21:05,719 Disastrous floods are becoming more and more frequent. 333 00:21:10,227 --> 00:21:16,032 Yet despite the threats, humans still love living on the water. 334 00:21:16,067 --> 00:21:20,032 [music playing] 335 00:21:20,067 --> 00:21:22,832 Cities like sydney, new york, shanghai, 336 00:21:22,841 --> 00:21:26,112 Tianjin, venice, these are all cities 337 00:21:26,147 --> 00:21:28,912 That are attached to the sea. 338 00:21:28,947 --> 00:21:31,232 Their infrastructure abuts right up to the sea. 339 00:21:31,307 --> 00:21:34,352 There's no space there for the water 340 00:21:34,387 --> 00:21:36,839 To come in the city to retreat. 341 00:21:36,914 --> 00:21:39,952 And so a lot of these places are building barriers or thinking 342 00:21:39,987 --> 00:21:41,799 About building barriers. 343 00:21:41,874 --> 00:21:44,759 But barriers can really only protect up to a point. 344 00:21:48,307 --> 00:21:51,232 Narrator: It's not just that seas are rising. 345 00:21:51,307 --> 00:21:56,072 They're becoming ever more polluted in the age of humans. 346 00:21:56,147 --> 00:22:00,912 One substance in particular is doing a great deal of damage, 347 00:22:00,947 --> 00:22:05,719 Though, like many inventions, it started out innocently enough. 348 00:22:08,707 --> 00:22:12,592 The story of plastic begins in unusual surroundings-- 349 00:22:12,627 --> 00:22:14,792 An american pool hall. 350 00:22:14,867 --> 00:22:17,392 In the mid 19th century, billiard balls 351 00:22:17,427 --> 00:22:18,992 Are made of ivory. 352 00:22:19,027 --> 00:22:21,792 They're not just expensive, they're fragile 353 00:22:21,827 --> 00:22:23,872 And break down over time. 354 00:22:23,907 --> 00:22:26,432 Chips come off the ball surface and affect 355 00:22:26,467 --> 00:22:30,752 The accuracy of shots, which the players don't like. 356 00:22:30,827 --> 00:22:32,832 Michael phelan is a renowned billiards 357 00:22:32,867 --> 00:22:38,032 Player and promoter who thinks there must be a better way. 358 00:22:38,067 --> 00:22:44,719 $10,000 to anyone to find a replacement for ivory. 359 00:22:49,874 --> 00:22:53,272 Narrator: The man who comes up with a solution is an engineer 360 00:22:53,347 --> 00:22:56,472 Named john wesley hyatt. 361 00:22:56,547 --> 00:23:00,032 He succeeds in producing a mass from cellulose nitrate 362 00:23:00,067 --> 00:23:05,232 And camphor which he calls celluloid. 363 00:23:05,307 --> 00:23:09,792 Hyatt, however, has no formal training in chemistry, 364 00:23:09,827 --> 00:23:13,119 And celluloid has properties he doesn't yet know. 365 00:23:18,147 --> 00:23:21,072 It's both flammable and explosive, 366 00:23:21,107 --> 00:23:23,792 Causing alarm in the saloons, according 367 00:23:23,827 --> 00:23:25,072 To reports from the time. 368 00:23:25,107 --> 00:23:27,999 [music playing] 369 00:23:30,467 --> 00:23:33,872 I'm sure we'll overcome this problem in time. 370 00:23:33,907 --> 00:23:36,679 [music playing] 371 00:23:39,107 --> 00:23:41,872 Narrator: Plastic develops quickly and becomes 372 00:23:41,907 --> 00:23:46,032 A staple of the age of humans. 373 00:23:46,107 --> 00:23:49,952 Lightweight, inexpensive, and durable, plastic 374 00:23:49,987 --> 00:23:52,999 Has changed much for the better. 375 00:23:53,074 --> 00:23:56,952 But the bad news is that these days, about 40 376 00:23:57,027 --> 00:24:01,159 Million tons of plastic end up in our rivers and oceans 377 00:24:01,234 --> 00:24:02,752 Every year. 378 00:24:02,827 --> 00:24:07,159 Its durability is a double-edged sword. 379 00:24:07,234 --> 00:24:11,792 Plastic bags alone account for much of the waste. 380 00:24:11,801 --> 00:24:16,272 Hundreds of billions of plastic bags are used just once 381 00:24:16,307 --> 00:24:18,839 And then discarded. 382 00:24:18,914 --> 00:24:23,312 But it's the plastic we don't see that's actually 383 00:24:23,347 --> 00:24:25,399 The bigger threat. 384 00:24:31,001 --> 00:24:34,679 Plastic in our oceans floats on the surface. 385 00:24:34,754 --> 00:24:38,832 As it's exposed to sun and waves, it breaks down. 386 00:24:38,867 --> 00:24:43,952 Eventually, it decays into tiny particles called microplastic 387 00:24:43,987 --> 00:24:46,112 Which finds its way into the food chain 388 00:24:46,147 --> 00:24:48,839 With troubling consequences. 389 00:24:48,914 --> 00:24:51,432 Its effects can be clearly seen here 390 00:24:51,507 --> 00:24:56,519 On a tiny island called lord howe about 350 miles off 391 00:24:56,594 --> 00:24:58,999 The coast of sydney, australia. 392 00:24:59,074 --> 00:25:01,552 Out here in the pacific ocean lies 393 00:25:01,587 --> 00:25:05,392 The southernmost tropical coral reef on our planet. 394 00:25:05,427 --> 00:25:10,032 A mere 400 people may visit the island each year. 395 00:25:10,067 --> 00:25:15,072 And at first glance, it looks like a paradise. 396 00:25:15,147 --> 00:25:17,752 But biologists are troubled by the health of birds 397 00:25:17,827 --> 00:25:23,432 Here, particularly one called the pale-footed shearwater. 398 00:25:23,507 --> 00:25:27,439 Each day, biologists find dead fledglings along the beaches. 399 00:25:34,467 --> 00:25:38,072 Even before an autopsy, they have a good idea 400 00:25:38,147 --> 00:25:39,199 Of its cause of death-- 401 00:25:43,627 --> 00:25:47,232 Plastic in the bird's stomach and intestines. 402 00:25:47,267 --> 00:25:52,439 Looks like we've got one piece of plastic right there. 403 00:25:55,347 --> 00:25:57,792 Shearwaters hunt in the sea and will 404 00:25:57,827 --> 00:25:59,399 Devour anything that floats. 405 00:26:03,627 --> 00:26:06,432 The birds can die from internal wounds caused 406 00:26:06,467 --> 00:26:10,032 By sharp-edged particles. 407 00:26:10,067 --> 00:26:14,432 But more often, they starve because they're unable to pass 408 00:26:14,507 --> 00:26:18,272 Plastic, so their stomachs become full 409 00:26:18,307 --> 00:26:20,159 And can't take in nutrients. 410 00:26:24,627 --> 00:26:28,312 Plastic threatens all marine animals, including 411 00:26:28,387 --> 00:26:30,592 Turtles, fish, and mammals. 412 00:26:30,667 --> 00:26:33,799 It contributes to climate change and threatens 413 00:26:33,874 --> 00:26:38,192 Ocean health, food safety and quality, and coastal tourism. 414 00:26:38,227 --> 00:26:41,279 [music playing] 415 00:26:44,667 --> 00:26:47,632 This beautiful island covered in plastic. 416 00:26:47,641 --> 00:26:50,672 People on that island, it's not even their plastic. 417 00:26:50,707 --> 00:26:53,312 It's just plastic washed around the world. 418 00:26:53,347 --> 00:26:56,272 And yeah, I don't think there's any place that 419 00:26:56,307 --> 00:26:58,199 Isn't covered with plastic now. 420 00:27:02,667 --> 00:27:05,159 Narrator: As night falls on lord howe, 421 00:27:05,234 --> 00:27:09,632 The scientific team is moving on to a special rescue mission. 422 00:27:09,667 --> 00:27:13,552 They're collecting shearwater fledglings hiding in the scrub 423 00:27:13,587 --> 00:27:17,152 While their parents are out looking for food. 424 00:27:17,187 --> 00:27:18,112 Ok. 425 00:27:18,187 --> 00:27:19,792 Next one, alex. 426 00:27:19,801 --> 00:27:22,272 Narrator: Lord howe is the only breeding site 427 00:27:22,307 --> 00:27:25,552 For these migratory seabirds along the eastern coast 428 00:27:25,587 --> 00:27:27,632 Of the continent, and their numbers 429 00:27:27,667 --> 00:27:31,712 Are declining year by year. 430 00:27:31,787 --> 00:27:33,392 We collect the feathers from the birds-- 431 00:27:33,427 --> 00:27:35,112 It takes only a quick moment-- 432 00:27:35,187 --> 00:27:37,232 Because these couple of feathers can tell us a lot of really 433 00:27:37,267 --> 00:27:38,632 Important information. 434 00:27:38,707 --> 00:27:40,192 When plastic is out floating in the ocean, 435 00:27:40,227 --> 00:27:41,799 It acts like a magnet or a sponge, 436 00:27:41,874 --> 00:27:45,232 And it concentrates pollutants onto its surface. 437 00:27:45,267 --> 00:27:47,872 And so when a seabird like this consumes that plastic 438 00:27:47,907 --> 00:27:51,232 Or a whale or a turtle, those chemicals 439 00:27:51,267 --> 00:27:54,632 Leach out into the bloodstream and inevitably into the 440 00:27:54,707 --> 00:27:56,199 Tissues, including feathers. 441 00:27:56,274 --> 00:27:57,872 And so I can send these off to the lab 442 00:27:57,947 --> 00:28:00,832 And figure out what chemicals this animal has been exposed 443 00:28:00,867 --> 00:28:03,319 To and whether or not that relates 444 00:28:03,394 --> 00:28:05,872 To the amount of plastic that I then find in the stomach. 445 00:28:05,907 --> 00:28:09,592 So something that is only a little bit painful 446 00:28:09,667 --> 00:28:11,792 And takes a brief second is actually 447 00:28:11,827 --> 00:28:14,119 Incredibly informative for a scientist like me. 448 00:28:19,267 --> 00:28:22,152 40.1. 449 00:28:22,227 --> 00:28:24,832 Narrator: To save as many fledglings as possible, 450 00:28:24,867 --> 00:28:28,192 The team performs an unusual operation. 451 00:28:28,227 --> 00:28:30,479 [music playing] 452 00:28:33,667 --> 00:28:34,839 They pump their stomachs. 453 00:28:43,307 --> 00:28:47,639 Tonight, every one of the birds has plastic in its belly. 454 00:28:47,714 --> 00:28:52,832 This chick alone has swallowed 13 pieces. 455 00:28:52,867 --> 00:28:59,232 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 plastic 456 00:28:59,267 --> 00:29:01,152 And a huge piece of hummus. 457 00:29:01,187 --> 00:29:01,839 Look at that. 458 00:29:04,547 --> 00:29:06,312 Narrator: Then it's off into the wild 459 00:29:06,387 --> 00:29:10,752 Again, where unfortunately, more plastic awaits, 460 00:29:10,787 --> 00:29:14,752 Even out here on a faraway island. 461 00:29:14,827 --> 00:29:18,359 Every ocean in the world contains plastic. 462 00:29:18,434 --> 00:29:22,432 More than 9 billion tons of it have been produced worldwide 463 00:29:22,467 --> 00:29:28,839 Since 1950, 18% in north america, another 18% in europe, 464 00:29:29,894 --> 00:29:33,792 And most of it from china, which produces the majority 465 00:29:33,827 --> 00:29:37,312 Of the world's consumer goods. 466 00:29:37,347 --> 00:29:39,552 Interpreter: Plastic has had unforeseen consequences 467 00:29:39,587 --> 00:29:41,872 During the history of mankind. 468 00:29:41,947 --> 00:29:43,959 As a young student, I always thought 469 00:29:44,034 --> 00:29:45,799 That if we divide historical periods 470 00:29:45,874 --> 00:29:47,472 According to certain metals-- 471 00:29:47,507 --> 00:29:50,752 The copper age, the bronze age, the iron age-- 472 00:29:50,827 --> 00:29:53,479 We ought to talk of the plastic or synthetic age 473 00:29:53,554 --> 00:29:56,759 If we refer to the era from the early 20th century onwards. 474 00:29:59,667 --> 00:30:03,272 Narrator: Back in australia near the great barrier reef, 475 00:30:03,347 --> 00:30:06,832 Students of the australian institute for marine science 476 00:30:06,867 --> 00:30:10,032 Are searching the beaches for microplastics, 477 00:30:10,067 --> 00:30:14,632 Tiny particles which are almost invisible to the eye. 478 00:30:14,707 --> 00:30:16,832 Research confirms that both humans 479 00:30:16,867 --> 00:30:19,632 And animals are ingesting more and more 480 00:30:19,667 --> 00:30:21,639 Microplastics every year. 481 00:30:24,387 --> 00:30:27,959 One indicator species is the tiny clownfish, 482 00:30:28,034 --> 00:30:32,632 An animal that lives on the reef by the thousands. 483 00:30:32,707 --> 00:30:36,632 Scientists want to know how much microplastic the clownfish take 484 00:30:36,707 --> 00:30:38,999 In and how much of it accumulates 485 00:30:39,074 --> 00:30:42,032 In their stomach and tissues. 486 00:30:42,067 --> 00:30:44,352 They also want to find out whether the fish 487 00:30:44,387 --> 00:30:49,472 Are able to discriminate between food and plastic. 488 00:30:49,507 --> 00:30:52,832 I was very surprised, when I first started this work 489 00:30:52,867 --> 00:30:55,552 On the great barrier reef, that we did find 490 00:30:55,587 --> 00:30:58,992 Microplastic contamination in every water sample 491 00:30:59,027 --> 00:31:02,839 That we took and in most of the fish that we analyzed. 492 00:31:07,074 --> 00:31:10,592 Narrator: Today, most of the plastic eaten by fish 493 00:31:10,627 --> 00:31:14,912 Consists of microfibers that enter the oceans as residues 494 00:31:14,947 --> 00:31:16,239 When we wash our clothes. 495 00:31:19,107 --> 00:31:22,672 10,000 microfibers weigh less than a fraction 496 00:31:22,707 --> 00:31:27,872 Of a single ounce and they're just one source of the problem. 497 00:31:27,907 --> 00:31:31,752 The microscope confirms that the intestines of the clownfish 498 00:31:31,827 --> 00:31:33,879 Are filled with microfibers. 499 00:31:37,507 --> 00:31:40,512 We know that microplastics come from sewage 500 00:31:40,547 --> 00:31:42,679 Treatment plants, for example. 501 00:31:42,754 --> 00:31:45,472 But importantly, it also comes from larger 502 00:31:45,507 --> 00:31:49,792 Plastic waste that ends up in the oceans and on the beaches. 503 00:31:49,801 --> 00:31:53,752 And specifically on beaches, they become very, very brittle 504 00:31:53,827 --> 00:31:55,872 Very quickly due to being exposed 505 00:31:55,907 --> 00:31:59,152 To the sun and the salt, and they break down very quickly 506 00:31:59,187 --> 00:32:01,872 Into smaller and smaller bits until eventually, 507 00:32:01,907 --> 00:32:04,839 They turn into microplastics. 508 00:32:04,914 --> 00:32:06,839 Narrator: Plastics are everywhere, 509 00:32:06,914 --> 00:32:10,432 Infecting every single form of marine life. 510 00:32:10,467 --> 00:32:14,359 Yet as bad as the problem is, it's not even the biggest 511 00:32:14,434 --> 00:32:15,879 Threat to our oceans. 512 00:32:18,547 --> 00:32:22,632 Oceans absorb heat and gases from the atmosphere. 513 00:32:22,707 --> 00:32:25,872 As carbon dioxide emissions increase, 514 00:32:25,907 --> 00:32:29,472 The oceans are absorbing about 30% of them, 515 00:32:29,507 --> 00:32:31,952 Making the water more acidic. 516 00:32:31,987 --> 00:32:35,112 Add to that rising sea water temperatures, 517 00:32:35,187 --> 00:32:37,592 And you get coral bleaching. 518 00:32:37,667 --> 00:32:39,952 It's a process that changes the algae 519 00:32:39,987 --> 00:32:42,632 That corals rely on for food. 520 00:32:42,707 --> 00:32:46,752 Eventually, the reefs starve and die. 521 00:32:46,787 --> 00:32:49,912 The first thing you see on the reef that has bleached, 522 00:32:49,987 --> 00:32:52,472 That has been exposed to higher temperatures, 523 00:32:52,547 --> 00:32:55,632 Is all of the individuals going white 524 00:32:55,667 --> 00:32:58,679 And all of these other fluorescent colors. 525 00:32:58,754 --> 00:33:01,432 So in the early stages of a bleaching event, 526 00:33:01,507 --> 00:33:06,192 It's quite a spectacular and beautiful phenomenon. 527 00:33:06,201 --> 00:33:09,792 But these colors are the colors of death. 528 00:33:09,827 --> 00:33:11,839 [music playing] 529 00:33:14,147 --> 00:33:16,199 The fish life has disappeared. 530 00:33:16,274 --> 00:33:18,992 All the small damselfish that typically 531 00:33:19,027 --> 00:33:23,159 Live within the branches of living coral have gone. 532 00:33:23,234 --> 00:33:26,199 So it really does feel like swimming 533 00:33:26,274 --> 00:33:29,519 Through a graveyard with the tombstones still intact. 534 00:33:32,147 --> 00:33:34,272 What our study shows is the corals, 535 00:33:34,307 --> 00:33:36,672 They're not being replaced. 536 00:33:36,707 --> 00:33:40,672 And so if they're not replaced, eventually, they'll 537 00:33:40,707 --> 00:33:42,672 All die out. 538 00:33:42,707 --> 00:33:44,519 Narrator: Too big to fail-- 539 00:33:44,594 --> 00:33:48,952 That's what people long thought about the great barrier reef. 540 00:33:49,027 --> 00:33:52,999 But some scientists are working on new and novel remedies 541 00:33:53,074 --> 00:33:55,239 And hoping for a cure. 542 00:33:58,707 --> 00:34:01,872 At the australian institute for marine science, 543 00:34:01,907 --> 00:34:05,592 They've managed to develop corals that can withstand 544 00:34:05,667 --> 00:34:08,592 Higher water temperatures, which may reduce 545 00:34:08,627 --> 00:34:12,792 The impact of coral bleaching. 546 00:34:12,867 --> 00:34:15,592 Corals in the study reproduce by releasing 547 00:34:15,667 --> 00:34:21,712 Larvae that drift in the sea until they settle down. 548 00:34:21,747 --> 00:34:25,592 At the lab, they provide the corals with pieces of limestone 549 00:34:25,667 --> 00:34:28,032 As their new settlements. 550 00:34:28,067 --> 00:34:31,872 The experiment can't be verified by the naked eye. 551 00:34:31,907 --> 00:34:36,912 It takes an electron microscope to do that. 552 00:34:36,947 --> 00:34:39,872 Each new coral that settles on the limestone 553 00:34:39,907 --> 00:34:42,912 Promises an option for saving the reefs. 554 00:34:42,947 --> 00:34:47,712 The tiny white dots are rays of hope, corals in the earliest 555 00:34:47,747 --> 00:34:49,632 Stage of growth. 556 00:34:49,667 --> 00:34:52,672 Despite these gains, whether the scientists here 557 00:34:52,707 --> 00:34:55,552 Can ensure the survival of the great barrier reef 558 00:34:55,587 --> 00:34:59,872 Is doubtful because the survival of a reef 559 00:34:59,947 --> 00:35:02,679 Doesn't depend on local conditions alone. 560 00:35:04,914 --> 00:35:08,192 Over on the west coast of australia in the east 561 00:35:08,227 --> 00:35:10,992 Indian ocean, scientists are studying 562 00:35:11,027 --> 00:35:14,679 Another reef called coral bay. 563 00:35:15,267 --> 00:35:19,912 It's part of the ningaloo reef, another unesco world heritage 564 00:35:19,987 --> 00:35:20,959 Site. 565 00:35:22,547 --> 00:35:26,672 Its corals are among the most beautiful and intact specimens 566 00:35:26,681 --> 00:35:28,032 In the world. 567 00:35:28,107 --> 00:35:30,272 Healthier than the great barrier reef, 568 00:35:30,347 --> 00:35:32,919 It's also fighting coral bleaching. 569 00:35:34,067 --> 00:35:37,159 Biologists regularly check sections of the reef 570 00:35:37,234 --> 00:35:38,992 To see how it's doing. 571 00:35:39,027 --> 00:35:41,392 They're heading to a problematic spot 572 00:35:41,427 --> 00:35:44,192 To see how bad the damage is. 573 00:35:44,201 --> 00:35:46,672 Whatever they find, they know it's 574 00:35:46,707 --> 00:35:50,079 Likely to get worse in the future due to climate change. 575 00:35:53,187 --> 00:35:56,112 I'm afraid the ningaloo reef will follow the same trajectory 576 00:35:56,147 --> 00:35:58,672 That we're seeing in coral reefs around the world-- 577 00:35:58,707 --> 00:36:00,839 The collapse of corals in the great barrier reef, 578 00:36:00,914 --> 00:36:02,272 In the caribbean. 579 00:36:02,307 --> 00:36:05,752 The corals here in a pristine state. 580 00:36:05,827 --> 00:36:07,952 There's little impact locally. 581 00:36:07,987 --> 00:36:09,072 But what's happening in europe, what's 582 00:36:09,107 --> 00:36:10,952 Happening in north america-- 583 00:36:11,027 --> 00:36:14,672 Increases in atmospheric co2-- is going to lead to increases 584 00:36:14,707 --> 00:36:16,992 In ocean temperatures, and that's going have an impact 585 00:36:17,027 --> 00:36:18,199 Right here at ningaloo. 586 00:36:22,274 --> 00:36:24,632 Narrator: The team finds their study area 587 00:36:24,707 --> 00:36:26,752 And marks the location. 588 00:36:26,827 --> 00:36:29,639 They'll compare photos of today to those 589 00:36:29,714 --> 00:36:31,872 That were taken in the past. 590 00:36:31,907 --> 00:36:34,679 Coral bleaching can occur in phases. 591 00:36:34,754 --> 00:36:37,392 If there is sufficient time between phases, 592 00:36:37,427 --> 00:36:40,912 It's possible for reefs to regenerate, 593 00:36:40,947 --> 00:36:43,152 Though it can take up to a decade. 594 00:36:43,161 --> 00:36:46,992 So far, coral bay has managed to recover 595 00:36:47,027 --> 00:36:50,912 From periods of bleaching. 596 00:36:50,947 --> 00:36:54,312 The team is also studying coral reproduction. 597 00:36:54,387 --> 00:36:57,232 They want to know how many larvae attach to the reef 598 00:36:57,267 --> 00:37:01,879 After spawning, a number that may indicate life or death. 599 00:37:04,067 --> 00:37:06,359 After the corals spawn, we've got all these coral larvae that 600 00:37:06,434 --> 00:37:08,839 Go up into the water column that might swim around for a couple 601 00:37:08,914 --> 00:37:10,672 Of days or a few weeks. 602 00:37:10,707 --> 00:37:13,792 And then they find a nice bit of habitat and settle on it. 603 00:37:13,801 --> 00:37:16,072 And what we used to count how many 604 00:37:16,147 --> 00:37:18,992 Corals are actually setting are these little settlement tiles. 605 00:37:19,027 --> 00:37:22,112 So we've had them out there from before the coral spawn, 606 00:37:22,187 --> 00:37:23,639 And we've just gone to pick them up. 607 00:37:23,714 --> 00:37:25,232 We'll take them back to the lab, have 608 00:37:25,267 --> 00:37:27,912 A look at the tiny little corals that are on there, 609 00:37:27,987 --> 00:37:29,959 Look at what species they are and how many there are. 610 00:37:32,434 --> 00:37:34,912 Narrator: First results are encouraging. 611 00:37:34,987 --> 00:37:37,872 In this area, corals are producing 612 00:37:37,907 --> 00:37:42,999 Enough offspring that are taking hold and growing as hoped. 613 00:37:43,074 --> 00:37:47,272 But the ningaloo reef stretches for more than 160 miles, 614 00:37:47,347 --> 00:37:51,319 And not all of it is doing so well. 615 00:37:56,947 --> 00:38:01,072 Scientists studying the ningaloo reef in western australia 616 00:38:01,147 --> 00:38:03,152 Are finding that parts of the reef 617 00:38:03,187 --> 00:38:06,152 Are lacking healthy numbers of young corals. 618 00:38:06,227 --> 00:38:08,792 It's not growing as it should. 619 00:38:08,867 --> 00:38:12,992 Its future may depend on worldwide co2 emissions, 620 00:38:13,027 --> 00:38:16,752 Though some, like the united nations group unesco, 621 00:38:16,827 --> 00:38:19,552 Are already predicting the worst. 622 00:38:19,587 --> 00:38:22,352 The unesco prediction of ningaloo ceasing 623 00:38:22,387 --> 00:38:25,319 To have a functional reef system by 2041 624 00:38:25,394 --> 00:38:27,079 Is indeed extremely alarming. We need to 625 00:38:29,827 --> 00:38:31,152 The important thing for us at the moment 626 00:38:31,161 --> 00:38:33,232 Is to build resilience in these systems. 627 00:38:33,307 --> 00:38:34,432 The world is going to change. 628 00:38:34,467 --> 00:38:35,792 The climate's going to change. 629 00:38:35,801 --> 00:38:37,479 We want to make the systems we've 630 00:38:37,554 --> 00:38:40,079 Got at the moment as resilient as possible to those changes. 631 00:38:42,841 --> 00:38:46,112 Narrator: It won't just be an underwater tragedy to lose 632 00:38:46,147 --> 00:38:48,112 The earth's coral reefs. 633 00:38:48,147 --> 00:38:50,512 Reefs around the world are barriers 634 00:38:50,547 --> 00:38:52,832 That protect the coasts. 635 00:38:52,867 --> 00:38:55,872 They help waves break offshore and prevent 636 00:38:55,907 --> 00:38:58,432 Beaches from washing away. 637 00:38:58,467 --> 00:39:00,912 Without those barriers, the beaches 638 00:39:00,947 --> 00:39:04,752 Erode and must be replenished, a costly and only 639 00:39:04,787 --> 00:39:06,952 Temporary solution. 640 00:39:07,027 --> 00:39:11,432 Still, waterfront development continues, and more and more 641 00:39:11,507 --> 00:39:14,519 Sand is forced into the water. 642 00:39:14,594 --> 00:39:19,159 Erosion and sand loss are very real problems for many beaches 643 00:39:19,234 --> 00:39:20,592 Around the world. 644 00:39:20,627 --> 00:39:24,032 The more we build, the more sand we need. 645 00:39:24,067 --> 00:39:26,959 And that sand can be hard to get. 646 00:39:30,547 --> 00:39:33,159 Building is one of the main activities 647 00:39:33,234 --> 00:39:37,872 In the age of humans, and it requires sand. 648 00:39:37,907 --> 00:39:40,032 But not all sand is the same. 649 00:39:40,067 --> 00:39:42,432 And for building, it must be coarse enough 650 00:39:42,467 --> 00:39:45,472 To provide grip and cohesion. 651 00:39:45,507 --> 00:39:48,472 In the desert, for instance, grains of sand 652 00:39:48,547 --> 00:39:51,472 Are ground into spheres by the wind. 653 00:39:51,507 --> 00:39:56,032 They're not suitable for concrete or mortar. 654 00:39:56,067 --> 00:39:59,912 Our world is literally built on sand. 655 00:39:59,987 --> 00:40:05,799 On average, a single family home requires about 200 tons of it. 656 00:40:07,554 --> 00:40:11,159 The gigantic construction projects in the arab world 657 00:40:11,234 --> 00:40:16,032 Actually depend on sand from other areas of the planet. 658 00:40:16,107 --> 00:40:19,872 Within the past 20 years, demand for sand and gravel 659 00:40:19,947 --> 00:40:20,639 Has tripled. 660 00:40:23,947 --> 00:40:28,519 By some estimates, we use about 40 billion tons of sand and gravel 661 00:40:28,594 --> 00:40:31,432 Annually to produce concrete, an amount 662 00:40:31,507 --> 00:40:34,632 Sufficient to erect a wall around the world 663 00:40:34,707 --> 00:40:39,072 88 feet high and wide. 664 00:40:39,107 --> 00:40:43,952 In ethiopia, it's actually being extracted illegally 665 00:40:43,987 --> 00:40:47,312 Because the worldwide demand is so high. 666 00:40:47,347 --> 00:40:50,432 The sand trade has become big business 667 00:40:50,467 --> 00:40:53,072 With profits in the billions. 668 00:40:53,107 --> 00:40:57,112 The workers on the front lines profit the least. 669 00:40:57,187 --> 00:40:59,959 The extraction of sand around bodies of water 670 00:41:00,034 --> 00:41:02,512 Has grave consequences. 671 00:41:02,547 --> 00:41:06,472 Rivers transport sand to the sea, and by doing so, 672 00:41:06,547 --> 00:41:09,959 Regularly fill up the beaches. 673 00:41:10,034 --> 00:41:14,432 Around the world, some 850,000 dams 674 00:41:14,507 --> 00:41:17,272 Are also interfering with sand flow, 675 00:41:17,347 --> 00:41:20,072 Changing the course of rivers and harming 676 00:41:20,147 --> 00:41:22,512 The animals that live in them. 677 00:41:22,547 --> 00:41:26,112 Yet we make this trade with nature because humans 678 00:41:26,147 --> 00:41:29,312 Need food, water, and energy. 679 00:41:29,347 --> 00:41:32,679 Changes in ecosystems-- greater sedimentation rates, 680 00:41:32,754 --> 00:41:35,312 Intense rainfall, global warming-- 681 00:41:35,321 --> 00:41:37,072 All of these things have happened 682 00:41:37,107 --> 00:41:42,472 All together many times in the history of the planet. 683 00:41:42,547 --> 00:41:49,152 But we know what the cause of our perturbation is. 684 00:41:49,187 --> 00:41:50,439 It's us. 685 00:41:51,987 --> 00:41:55,152 Narrator: As we continue to rely on earth's water to live, 686 00:41:55,187 --> 00:41:58,312 The age of humans is marked by questions 687 00:41:58,387 --> 00:42:01,072 Of priorities and balance. 688 00:42:01,147 --> 00:42:04,112 What's at stake is graphically illustrated 689 00:42:04,147 --> 00:42:06,792 By those reefs which are still intact, 690 00:42:06,867 --> 00:42:08,879 Such as the ningaloo reef. 691 00:42:09,447 --> 00:42:12,272 Coral reefs, like the rainforests, 692 00:42:12,347 --> 00:42:15,632 Are the most biodiverse regions of our planet, 693 00:42:15,667 --> 00:42:18,632 And biodiversity is essential. 694 00:42:18,707 --> 00:42:23,232 It's our life support, fueling the ecosystems that supply us 695 00:42:23,267 --> 00:42:27,072 With clean air and water, pollination of plants, 696 00:42:27,107 --> 00:42:30,512 Pest control, and much more. 697 00:42:30,547 --> 00:42:34,112 The very technology that allows us to see and record 698 00:42:34,147 --> 00:42:36,512 These natural wonders was developed 699 00:42:36,521 --> 00:42:41,552 In an age that's changing the earth at a rapid pace. 700 00:42:41,587 --> 00:42:44,632 As humans, we've used our natural gifts 701 00:42:44,707 --> 00:42:49,632 To create and invent in order to take care of ourselves. 702 00:42:49,667 --> 00:42:52,472 At first, any damage we might have done 703 00:42:52,547 --> 00:42:54,752 Wasn't well understood. 704 00:42:54,787 --> 00:42:58,312 But now science is giving us all kinds 705 00:42:58,387 --> 00:43:01,712 Of indicators that the planet is suffering 706 00:43:01,747 --> 00:43:03,239 And that we're the cause. 707 00:43:06,507 --> 00:43:08,672 Without the environment, there is no culture. 708 00:43:08,707 --> 00:43:11,639 Without the environment, there is no human history. 709 00:43:11,714 --> 00:43:14,672 And certainly, without a viable environment, 710 00:43:14,681 --> 00:43:16,832 There is no human future. 711 00:43:16,867 --> 00:43:18,639 And we're in a dance together. 712 00:43:23,507 --> 00:43:25,872 Narrator: Humanity's will and decision-making 713 00:43:25,907 --> 00:43:28,272 Are being tested. 714 00:43:28,307 --> 00:43:31,112 Will we heed the warnings of our planet, 715 00:43:31,187 --> 00:43:33,799 Or will we keep pushing to a point of no return? 716 00:43:37,507 --> 00:43:41,592 We have the power to bring about either result. 717 00:43:41,667 --> 00:43:44,312 What we do in the next few years is 718 00:43:44,387 --> 00:43:49,872 Critical to how the story of the age of humans will be written. 719 00:43:49,947 --> 00:43:53,439 [music playing]