1 00:00:00,866 --> 00:00:03,466 ♪ 2 00:00:06,533 --> 00:00:08,933 NARRATOR:Are rising temperatures driving 3 00:00:08,966 --> 00:00:12,600 Earth's ecosystems past a point of no return? 4 00:00:12,633 --> 00:00:14,133 JANE LONG: We can't go back. 5 00:00:14,166 --> 00:00:15,566 {\an1}There is no path backwards. 6 00:00:15,600 --> 00:00:18,900 {\an8}STEVE PACALA: Every year, the damages are worse. 7 00:00:18,933 --> 00:00:22,066 NARRATOR: We have promising technologies 8 00:00:22,100 --> 00:00:24,666 {\an1}that put solutions within our grasp, 9 00:00:24,700 --> 00:00:27,800 {\an1}but are we reaching far enough? 10 00:00:27,833 --> 00:00:29,533 FRANK KEUTSCH: We have to have emissions 11 00:00:29,566 --> 00:00:30,700 cut to zero. 12 00:00:30,733 --> 00:00:33,066 {\an1}Even if we stop emitting CO2, 13 00:00:33,100 --> 00:00:36,900 {\an1}we still have the CO2 we've already emitted. 14 00:00:36,933 --> 00:00:39,500 NARRATOR: So scientists are building a new toolkit... 15 00:00:39,533 --> 00:00:40,933 ATTICUS STOVALL: It has power. 16 00:00:40,966 --> 00:00:43,266 NARRATOR: ...to ensure a prosperous future. 17 00:00:43,300 --> 00:00:44,700 {\an1}Our society has to survive. 18 00:00:44,733 --> 00:00:48,166 SHEILA JASANOFF: We need to reduce the heating effect. 19 00:00:48,200 --> 00:00:50,400 NARRATOR: Cutting-edge solutions... 20 00:00:50,433 --> 00:00:52,500 ALDO STEINFELD:It's going to be revolutionary. 21 00:00:52,533 --> 00:00:55,466 {\an1}LOLA FATOYINBO AGUEH: It's like science fiction. 22 00:00:55,500 --> 00:00:56,633 DAVID KEITH: And there's the balloon up there. 23 00:00:56,666 --> 00:00:59,300 NARRATOR: ...and high-risk measures... 24 00:00:59,333 --> 00:01:02,533 {\an1}I really hope we'll never have to do this. 25 00:01:02,566 --> 00:01:05,200 {\an1}It's really important that humanity has a backstop. 26 00:01:05,233 --> 00:01:07,733 NARRATOR: ...in a race to discover: 27 00:01:07,766 --> 00:01:10,066 {\an1}can we cool the planet? 28 00:01:10,100 --> 00:01:12,000 {\an1}Right now, on "NOVA." 29 00:01:12,033 --> 00:01:15,866 ♪ 30 00:01:15,900 --> 00:01:18,533 ANNOUNCER: Major funding for "NOVA" is provided by the following: 31 00:01:32,800 --> 00:01:35,966 JASANOFF: It's a new time in the Earth's history 32 00:01:36,000 --> 00:01:40,233 {\an1}in which we are not just inhabiting our planet, 33 00:01:40,266 --> 00:01:43,666 {\an1}we're operating as stewards of the very thing 34 00:01:43,700 --> 00:01:46,800 {\an1}that we're living on. 35 00:01:46,833 --> 00:01:51,166 NARRATOR:Since the Industrial Revolution, humanity has been running 36 00:01:51,200 --> 00:01:53,466 {\an1}an unintentional experiment 37 00:01:53,500 --> 00:01:55,366 {\an1}in Earth's atmosphere, 38 00:01:55,400 --> 00:01:58,266 {\an1}pushing the climate to new extremes. 39 00:01:58,300 --> 00:02:00,200 LONG: Things are going to get hot. 40 00:02:00,233 --> 00:02:02,433 MAN: Boy, you can feel the heat. 41 00:02:02,466 --> 00:02:03,400 This is insane! 42 00:02:03,433 --> 00:02:05,866 Oh, my God. 43 00:02:05,900 --> 00:02:08,266 PACALA: Attitudes have changed rapidly 44 00:02:08,300 --> 00:02:11,100 {\an1}because everyone can see for themselves 45 00:02:11,133 --> 00:02:14,633 {\an1}the climate change that is occurring. 46 00:02:14,666 --> 00:02:17,900 NARRATOR:A child born today will witness, across her lifetime, 47 00:02:17,933 --> 00:02:21,700 {\an1}a planet transformed by rising temperature. 48 00:02:21,733 --> 00:02:24,266 MAN: I got you, I got you. 49 00:02:25,700 --> 00:02:28,233 NARRATOR: How did we get here? 50 00:02:28,266 --> 00:02:30,633 ♪ 51 00:02:30,666 --> 00:02:32,333 LONG:Every time you get in your car, 52 00:02:32,366 --> 00:02:33,733 every time you fly a plane, 53 00:02:33,766 --> 00:02:35,600 every time you turn the heat on, 54 00:02:35,633 --> 00:02:37,600 {\an1}all of those things are putting carbon dioxide 55 00:02:37,633 --> 00:02:39,033 {\an1}into the atmosphere, 56 00:02:39,066 --> 00:02:41,300 {\an7}and if there's more carbon dioxide in the atmosphere, 57 00:02:41,333 --> 00:02:44,933 {\an7}there's a higher temperature. 58 00:02:44,966 --> 00:02:48,600 {\an8}NARRATOR: And now temperatures have started to spike. 59 00:02:48,633 --> 00:02:51,366 KEITH: If we keep pumping billions of tons of CO2 60 00:02:51,400 --> 00:02:52,866 {\an1}into the atmosphere each year, 61 00:02:52,900 --> 00:02:55,533 {\an1}we really will cook ourselves, literally, in the end. 62 00:02:55,566 --> 00:02:57,866 {\an1}(birds squawking) 63 00:02:57,900 --> 00:02:59,466 NARRATOR: To stop the worst impacts 64 00:02:59,500 --> 00:03:03,233 {\an1}of planetary heating, we need rapid emissions cuts, 65 00:03:03,266 --> 00:03:06,166 starting now. 66 00:03:06,200 --> 00:03:08,033 PACALA: The developed nations of the world 67 00:03:08,066 --> 00:03:10,666 need to go fromthe energy system they have now 68 00:03:10,700 --> 00:03:15,800 to one that emits nothing, zero, in 30 years' time. 69 00:03:18,400 --> 00:03:20,033 ♪ 70 00:03:20,066 --> 00:03:22,766 {\an1}The good news is, we know how to do that. 71 00:03:22,800 --> 00:03:26,566 {\an1}Renewables now are the cheapest form of electricity 72 00:03:26,600 --> 00:03:28,000 on two-thirds of the Earth's surface, 73 00:03:28,033 --> 00:03:29,300 and it's going to be everywhere. 74 00:03:29,333 --> 00:03:34,433 {\an8}NARRATOR: A world of carbon-free energy is coming. 75 00:03:34,466 --> 00:03:35,900 {\an7}(thunder crackling) 76 00:03:35,933 --> 00:03:38,300 {\an7}But climate impacts are coming faster. 77 00:03:38,333 --> 00:03:40,800 {\an8}KATE MURPHY: Lasers are at power. 78 00:03:40,833 --> 00:03:42,400 {\an8}There it is. 79 00:03:42,433 --> 00:03:46,066 {\an8}NARRATOR: So scientists are openinga second front in the battle... 80 00:03:46,100 --> 00:03:47,533 {\an8}STOVALL: Sweet. It has power. 81 00:03:47,566 --> 00:03:49,366 {\an8}NARRATOR: Bringing new technologies 82 00:03:49,400 --> 00:03:51,800 {\an7}to bear on the way we fight climate change... 83 00:03:51,833 --> 00:03:53,666 {\an8}FATOYINBO AGUEH: We now have so much data. 84 00:03:53,700 --> 00:03:55,900 {\an8}This is going to be a game-changer. 85 00:03:55,933 --> 00:03:59,600 {\an8}PACALA: There are a whole class of solutions 86 00:03:59,633 --> 00:04:02,566 {\an1}to actually get this job all the way done. 87 00:04:04,266 --> 00:04:06,600 NARRATOR:By removing CO2 from the air... 88 00:04:06,633 --> 00:04:07,633 {\an1}SANDRA SNAEBJORNSDOTTIR: This little guy, 89 00:04:07,666 --> 00:04:10,300 {\an1}this is just the beginning. 90 00:04:10,333 --> 00:04:12,900 NARRATOR: Converting CO2 from a waste 91 00:04:12,933 --> 00:04:14,400 to a resource... 92 00:04:14,433 --> 00:04:18,766 APOORV SINHA: We see this kind of as a testing ground. 93 00:04:18,800 --> 00:04:21,600 NARRATOR: Even extreme measures, 94 00:04:21,633 --> 00:04:25,433 like shielding us from the sun. 95 00:04:25,466 --> 00:04:26,600 {\an1}(machinery whirring) 96 00:04:26,633 --> 00:04:28,033 PACALA: There's been a technical revolution 97 00:04:28,066 --> 00:04:29,800 {\an1}in the last few years 98 00:04:29,833 --> 00:04:32,233 {\an1}that's unlike anything we've seen 99 00:04:32,266 --> 00:04:35,766 {\an1}in the previous hundred. 100 00:04:35,800 --> 00:04:38,800 {\an1}This is a problem with a solution. 101 00:04:38,833 --> 00:04:43,733 NARRATOR: Can a new wave of climate tech take us the rest of the way 102 00:04:43,766 --> 00:04:46,900 to turn down the global thermostat? 103 00:04:46,933 --> 00:04:49,700 KEUTSCH: We need to look at everything that's out there-- 104 00:04:49,733 --> 00:04:51,533 {\an1}natural solutions, 105 00:04:51,566 --> 00:04:53,466 {\an1}CO2 sequestration, 106 00:04:53,500 --> 00:04:56,866 {\an1}solar geoengineering. 107 00:04:56,900 --> 00:04:59,133 {\an1}There may be this idea out therethat nobody has come up with yet 108 00:04:59,166 --> 00:05:01,066 {\an1}that could be really transformative. 109 00:05:01,100 --> 00:05:06,233 ♪ 110 00:05:13,133 --> 00:05:16,833 {\an8}NARRATOR:Cooling the planet means, first, stopping more CO2 111 00:05:16,866 --> 00:05:18,866 {\an7}from entering the atmosphere 112 00:05:18,900 --> 00:05:22,600 {\an7}and then finding ways to remove it. 113 00:05:22,633 --> 00:05:27,833 {\an7}But just how much CO2 are we talking about? 114 00:05:27,866 --> 00:05:31,433 {\an7}Imagine you filled the National Mall all the way 115 00:05:31,466 --> 00:05:35,733 {\an7}from the Lincoln Memorial to the Capitol steps with coal... 116 00:05:35,766 --> 00:05:40,633 ♪ 117 00:05:40,666 --> 00:05:42,500 {\an1}...and you piled it up all the way 118 00:05:42,533 --> 00:05:48,233 {\an1}to the top of the Washington Monument ten times. 119 00:05:48,266 --> 00:05:52,400 {\an1}That would be a gigaton of coal. 120 00:05:52,433 --> 00:05:58,300 {\an7}"Giga" means billion, so that's a billion tons. 121 00:05:58,333 --> 00:06:02,433 {\an7}Now, we actually burn ten times that much carbon every year. 122 00:06:02,466 --> 00:06:05,666 {\an1}People actually go dig that stuff up out of the ground, 123 00:06:05,700 --> 00:06:07,433 {\an1}ten billion tons of it, 124 00:06:07,466 --> 00:06:11,166 {\an1}and set it on fire in power plants, in engines, 125 00:06:11,200 --> 00:06:12,966 {\an1}in factories all over the world. 126 00:06:13,000 --> 00:06:14,400 {\an1}(imitating combustion) 127 00:06:14,433 --> 00:06:17,300 ♪ 128 00:06:17,333 --> 00:06:20,233 And then because that carbon has reacted with oxygen, 129 00:06:20,266 --> 00:06:22,266 {\an1}ten gigatons of carbon is burned, 130 00:06:22,300 --> 00:06:27,833 {\an1}but it creates 37 gigatons of CO2. 131 00:06:27,866 --> 00:06:33,033 NARRATOR:At our current rate, that's just one year of CO2 emissions. 132 00:06:33,066 --> 00:06:35,200 ♪ 133 00:06:35,233 --> 00:06:38,333 {\an1}To blunt the impacts of heating the planet, 134 00:06:38,366 --> 00:06:41,033 {\an1}we need to shrink that number, 135 00:06:41,066 --> 00:06:42,300 to zero. 136 00:06:42,333 --> 00:06:47,200 ♪ 137 00:06:47,233 --> 00:06:50,633 {\an1}But there's another problem-- 138 00:06:50,666 --> 00:06:53,200 {\an1}the gigatons that came before. 139 00:06:53,233 --> 00:06:55,633 LONG: The single most important fact about climate change 140 00:06:55,666 --> 00:06:58,333 {\an7}is that the carbon dioxidethat we emit into the atmosphere 141 00:06:58,366 --> 00:07:00,533 {\an8}stays there for thousands of years. 142 00:07:00,566 --> 00:07:05,266 {\an8}NARRATOR: Year after year, we live with the carbon dioxide 143 00:07:05,300 --> 00:07:10,133 {\an7}we've added over time-- nearly 1,000 metric gigatons 144 00:07:10,166 --> 00:07:13,900 {\an7}since the Industrial Revolution began. 145 00:07:13,933 --> 00:07:16,533 LONG: Almost everything we emit stays there, 146 00:07:16,566 --> 00:07:18,100 {\an1}and it's staying there 147 00:07:18,133 --> 00:07:20,533 {\an1}until you do something about taking it out. 148 00:07:20,566 --> 00:07:22,300 ♪ 149 00:07:22,333 --> 00:07:25,000 NARRATOR: Pulling CO2 out of the air. 150 00:07:25,033 --> 00:07:28,800 {\an1}(men speaking on radios) 151 00:07:28,833 --> 00:07:30,333 NARRATOR: It sounds futuristic, 152 00:07:30,366 --> 00:07:32,400 {\an1}but it's a problem we've encountered before. 153 00:07:32,433 --> 00:07:35,400 JAN WURZBACHER: Remember Apollo 13? 154 00:07:35,433 --> 00:07:37,433 It was all about CO2 filtering, right? 155 00:07:37,466 --> 00:07:39,366 {\an8}That was the big problem, how to get the CO2 out of the air. 156 00:07:39,400 --> 00:07:41,700 {\an1}(indistinct radio chatter) 157 00:07:41,733 --> 00:07:43,833 NARRATOR:In 1970, following an accident, 158 00:07:43,866 --> 00:07:48,333 the crew of Apollo 13 aborted a mission to land on the moon. 159 00:07:48,366 --> 00:07:51,066 {\an1}JOHN SWIGERT (archival): Houston, we've had a problem. 160 00:07:51,100 --> 00:07:53,900 NARRATOR: Forced to return to Earth in a smaller capsule, 161 00:07:53,933 --> 00:07:56,633 {\an1}the astronauts faced a big problem. 162 00:07:56,666 --> 00:07:58,033 WURZBACHER: You're in confined spaces. 163 00:07:58,066 --> 00:07:59,233 {\an1}People exhale CO2. 164 00:07:59,266 --> 00:08:00,566 {\an1}You need to remove that CO2. 165 00:08:00,600 --> 00:08:03,166 (person exhales) 166 00:08:03,200 --> 00:08:07,233 NARRATOR: Every exhale caused carbon dioxide to build up, 167 00:08:07,266 --> 00:08:10,866 making the air increasingly toxic. 168 00:08:10,900 --> 00:08:12,666 MAN (archival): Okay, now, let's everybody keep cool. 169 00:08:12,700 --> 00:08:13,933 {\an1}Let's solve the problem 170 00:08:13,966 --> 00:08:17,300 {\an1}but let's not make it any worse by guessing. 171 00:08:17,333 --> 00:08:18,900 ♪ 172 00:08:18,933 --> 00:08:22,400 NARRATOR: The astronauts survivedby modifying their air scrubber 173 00:08:22,433 --> 00:08:24,833 to remove more carbon dioxide. 174 00:08:24,866 --> 00:08:29,533 (air flowing) 175 00:08:29,566 --> 00:08:33,233 {\an1}Inside the scrubber, negatively charged sites 176 00:08:33,266 --> 00:08:37,233 {\an1}on the filter polarize and bond with the CO2, 177 00:08:37,266 --> 00:08:41,500 {\an1}removing it from the air. 178 00:08:41,533 --> 00:08:46,866 {\an1}Could something like this work in Earth's atmosphere? 179 00:08:46,900 --> 00:08:48,633 DENNING: There's not a lot of CO2 in the air compared to 180 00:08:48,666 --> 00:08:50,633 {\an1}nitrogen and oxygen. 181 00:08:50,666 --> 00:08:54,200 {\an1}Imagine a box with 10,000 ping pong balls in it 182 00:08:54,233 --> 00:08:56,333 and four of them are painted black-- 183 00:08:56,366 --> 00:09:01,066 {\an1}those are the CO2 molecules. 184 00:09:01,100 --> 00:09:03,300 {\an1}Trying to find those four balls out of that big box 185 00:09:03,333 --> 00:09:05,233 {\an1}full of ping pong balls is hard! 186 00:09:05,266 --> 00:09:10,100 {\an8}♪ 187 00:09:12,600 --> 00:09:16,933 NARRATOR: Removing CO2 from a spacecraft is one thing. 188 00:09:16,966 --> 00:09:21,100 Removing it from our atmosphere poses a much bigger challenge. 189 00:09:21,133 --> 00:09:23,666 ♪ 190 00:09:23,700 --> 00:09:26,000 Is it realistic? 191 00:09:26,033 --> 00:09:28,800 WURZBACHER: Most people to whom we told we are taking CO2 192 00:09:28,833 --> 00:09:31,000 {\an1}out of the air would say, "You're crazy." 193 00:09:33,466 --> 00:09:36,733 {\an1}But here you see a full-scale direct air capture plant. 194 00:09:36,766 --> 00:09:39,866 {\an1}You see it consists of 12 individual modules 195 00:09:39,900 --> 00:09:41,366 {\an1}capturing the CO2 out of the air. 196 00:09:41,400 --> 00:09:43,700 ♪ 197 00:09:43,733 --> 00:09:46,033 NARRATOR: Jan Wurzbacher is a co-founder 198 00:09:46,066 --> 00:09:49,200 of Climeworks, a Swiss start-up specializing 199 00:09:49,233 --> 00:09:53,866 in what's called direct air capture. 200 00:09:53,900 --> 00:09:58,033 {\an1}Through this side, we suck in ambient air with 400 PPM-- 201 00:09:58,066 --> 00:10:00,466 {\an1}that's 400 parts per million CO2. 202 00:10:00,500 --> 00:10:04,433 ♪ 203 00:10:04,466 --> 00:10:09,833 And on the other side, we expel about 100 PPM CO2 content. 204 00:10:09,866 --> 00:10:13,200 {\an1}So three-quarters are kept inside. 205 00:10:13,233 --> 00:10:16,800 NARRATOR: A filter with highly reactive chemicals called amines 206 00:10:16,833 --> 00:10:22,200 {\an1}catches even small concentrations of CO2. 207 00:10:22,233 --> 00:10:25,900 {\an1}Heating the filter then breaks the bond. 208 00:10:25,933 --> 00:10:30,766 WURZBACHER:You release the CO2 and you can extract pure concentrated CO2. 209 00:10:30,800 --> 00:10:32,833 {\an1}And then you start all over again. 210 00:10:32,866 --> 00:10:38,833 ♪ 211 00:10:38,866 --> 00:10:44,633 NARRATOR:But generating the energy to do this can produce its own CO2. 212 00:10:44,666 --> 00:10:46,466 ♪ 213 00:10:46,500 --> 00:10:48,533 {\an1}Their solution for that 214 00:10:48,566 --> 00:10:50,466 is garbage. 215 00:10:50,500 --> 00:10:53,600 {\an1}Here we are on top of the waste incineration plant. 216 00:10:53,633 --> 00:10:56,166 {\an1}The reason why we're here is the main energy source 217 00:10:56,200 --> 00:10:59,900 {\an1}for our process of CO2 capture from the air, 218 00:10:59,933 --> 00:11:04,400 {\an1}waste heat from the incineration process. 219 00:11:04,433 --> 00:11:08,266 NARRATOR:Heat that would have been wasted instead heats the filters 220 00:11:08,300 --> 00:11:10,300 {\an1}inside the array, 221 00:11:10,333 --> 00:11:14,733 {\an1}which capture nearly 1,500metric tons of pure CO2 a year-- 222 00:11:14,766 --> 00:11:19,233 {\an1}about what's expelledfrom the tailpipes of 300 cars. 223 00:11:26,533 --> 00:11:28,000 PACALA: Once you've pulled 224 00:11:28,033 --> 00:11:31,600 {\an7}CO2 out of the atmosphere with a direct air capture machine, 225 00:11:31,633 --> 00:11:34,600 {\an1}the question is what to do with it. 226 00:11:34,633 --> 00:11:35,933 WURZBACHER: The big picture is taking 227 00:11:35,966 --> 00:11:37,833 {\an1}one percent of CO2 out of the atmosphere 228 00:11:37,866 --> 00:11:39,700 within the next five to ten years-- 229 00:11:39,733 --> 00:11:45,066 {\an1}that is roughly 400 milliontons-- and store it underground. 230 00:11:45,100 --> 00:11:47,100 {\an8}♪ 231 00:11:47,133 --> 00:11:50,566 NARRATOR: Could we put carbon right back where we found it-- 232 00:11:50,600 --> 00:11:52,533 underground? 233 00:11:52,566 --> 00:11:55,433 PACALA: There are lots of rocks near the surface of the Earth 234 00:11:55,466 --> 00:11:58,933 {\an1}that would want to bond spontaneously with CO2. 235 00:11:58,966 --> 00:12:01,633 {\an1}There's enough of thesekinds of minerals that you could 236 00:12:01,666 --> 00:12:06,200 {\an1}remove all of the atmospheric CO2 many, many times over. 237 00:12:06,233 --> 00:12:10,466 ♪ 238 00:12:10,500 --> 00:12:15,800 {\an8}NARRATOR: One of the best places to try that out is Iceland. 239 00:12:18,166 --> 00:12:22,133 ♪ 240 00:12:26,300 --> 00:12:27,300 {\an1}SNAEBJORNSDOTTIR: Here we are-- 241 00:12:27,333 --> 00:12:31,366 {\an1}the land of ice and fire. (laughs) 242 00:12:31,400 --> 00:12:33,166 {\an1}We have eruptions. 243 00:12:33,200 --> 00:12:35,333 {\an1}We have earthquakes. 244 00:12:35,366 --> 00:12:40,933 NARRATOR:Iceland is an island formed outof volcanic rock called basalt. 245 00:12:40,966 --> 00:12:43,966 We see the basaltic mountains here around me 246 00:12:44,000 --> 00:12:49,533 {\an1}and actually extending several kilometers downwards. 247 00:12:50,966 --> 00:12:54,633 NARRATOR: Basalt is porous rock that readily bonds with CO2 248 00:12:54,666 --> 00:12:58,300 over centuries. 249 00:12:58,333 --> 00:13:03,133 {\an1}Sandra Snaebjornsdottir's team has found a way 250 00:13:03,166 --> 00:13:05,700 {\an1}to speed up that process. 251 00:13:05,733 --> 00:13:07,600 {\an1}SNAEBJORNSDOTTIR: CarbFix is the method 252 00:13:07,633 --> 00:13:13,566 of capturing CO2 and turning it into stone. 253 00:13:13,600 --> 00:13:18,533 It's magic, but it's magic that already occurs in nature. 254 00:13:21,233 --> 00:13:24,933 NARRATOR:CarbFix is turning one-third of the CO2 from this power plant 255 00:13:24,966 --> 00:13:30,033 into solid rock in less than two years. 256 00:13:30,066 --> 00:13:33,666 {\an1}The key is water. 257 00:13:33,700 --> 00:13:39,033 {\an1}Inside this scrubber, gaseous CO2 is dissolved in water 258 00:13:39,066 --> 00:13:40,833 {\an1}to react with basalt more quickly. 259 00:13:40,866 --> 00:13:42,900 {\an1}SNAEBJORNSDOTTIR: This scrubber is actually 260 00:13:42,933 --> 00:13:44,833 {\an1}just a giant SodaStream. 261 00:13:46,266 --> 00:13:49,066 NARRATOR: The fizzy water is then pumped into injection wells. 262 00:13:49,100 --> 00:13:52,900 {\an1}SNAEBJORNSDOTTIR: This is actually my favorite part of it all. 263 00:13:52,933 --> 00:13:55,533 {\an1}From here, the magic starts to happen. 264 00:13:57,000 --> 00:14:00,833 This pipe extends to over 2,000 feet. 265 00:14:00,866 --> 00:14:06,933 {\an1}And there, we finally release this fluid to the rock. 266 00:14:06,966 --> 00:14:10,233 ♪ 267 00:14:10,266 --> 00:14:15,066 NARRATOR: Once inside the basalt, thedissolved CO2 reacts with metals 268 00:14:15,100 --> 00:14:21,333 {\an1}in the rock to form new solidminerals like calcium carbonate. 269 00:14:21,366 --> 00:14:24,166 {\an1}Once we have injected the CO2 into the rock, 270 00:14:24,200 --> 00:14:28,033 {\an7}it's there forever. 271 00:14:28,066 --> 00:14:30,266 NARRATOR: And Sandra is looking beyond Iceland. 272 00:14:30,300 --> 00:14:31,633 {\an1}She is test-driving 273 00:14:31,666 --> 00:14:36,833 {\an1}a direct air capture unit that can suck up CO2 anywhere. 274 00:14:36,866 --> 00:14:39,000 {\an1}SNAEBJORNSDOTTIR: We don't need the power plant. 275 00:14:39,033 --> 00:14:40,266 This can be done 276 00:14:40,300 --> 00:14:43,900 {\an1}anywhere where you have a formation to store your CO2. 277 00:14:43,933 --> 00:14:46,166 {\an8}♪ 278 00:14:46,200 --> 00:14:51,966 {\an8}LONG: What that means is, you can go backwards. 279 00:14:52,000 --> 00:14:57,066 ♪ 280 00:14:57,100 --> 00:14:59,200 {\an7}You can reverse the process 281 00:14:59,233 --> 00:15:01,433 {\an7}of emitting carbon dioxide into the air. 282 00:15:01,466 --> 00:15:05,966 NARRATOR:Negative emissions technologies like direct air capture 283 00:15:06,000 --> 00:15:09,533 {\an1}could play a role in reaching net zero, 284 00:15:09,566 --> 00:15:12,966 {\an1}the moment when humans removeas much CO2 from the atmosphere 285 00:15:13,000 --> 00:15:14,833 {\an1}as they put in. 286 00:15:16,133 --> 00:15:21,833 {\an1}So why isn't this the ultimate answer to our CO2 problem? 287 00:15:21,866 --> 00:15:23,200 LONG: These technologies are 288 00:15:23,233 --> 00:15:26,033 {\an1}very hard to scale up to a meaningful amount. 289 00:15:26,066 --> 00:15:27,600 ♪ 290 00:15:27,633 --> 00:15:30,166 WURZBACHER: The base module of our direct air capture plant, 291 00:15:30,200 --> 00:15:32,333 that's a 40-foot shipping container. 292 00:15:33,900 --> 00:15:37,733 In order to take one percent ofglobal emissions out of the air, 293 00:15:37,766 --> 00:15:44,433 {\an1}we would need 750,000 shipping containers. 294 00:15:44,466 --> 00:15:49,433 NARRATOR: All to remove just half agigaton of our annual emissions. 295 00:15:49,466 --> 00:15:51,633 ♪ 296 00:15:51,666 --> 00:15:54,700 DENNING: Direct air capture is very expensive 297 00:15:54,733 --> 00:15:59,500 and it takes energy to suck CO2 out of the air. 298 00:15:59,533 --> 00:16:01,600 {\an1}So I hope you're not imagining 299 00:16:01,633 --> 00:16:05,033 {\an1}direct air capture vacuuming upthe entire fossil fuel emissions 300 00:16:05,066 --> 00:16:07,166 {\an7}of the world, because it ain't gonna happen. 301 00:16:07,200 --> 00:16:13,033 NARRATOR: We'll need lower-cost clean energy everywhere 302 00:16:13,066 --> 00:16:15,700 {\an1}before the promise of direct air capture can meet 303 00:16:15,733 --> 00:16:17,500 {\an1}the scale of the problem. 304 00:16:17,533 --> 00:16:19,433 (switch clicks) 305 00:16:19,466 --> 00:16:21,100 M7 is on. 306 00:16:21,133 --> 00:16:26,966 NARRATOR: So some are exploring another idea: recycling our emissions. 307 00:16:27,000 --> 00:16:29,366 {\an3}MAN: Correction factor 0.7. 308 00:16:29,400 --> 00:16:34,166 LONG: We need to think about this problem very pragmatically. 309 00:16:34,200 --> 00:16:35,966 We can electrify a lot of things. 310 00:16:36,000 --> 00:16:38,433 {\an1}But there are certain parts of the energy system 311 00:16:38,466 --> 00:16:39,800 {\an1}that are extremely hard to decarbonize. 312 00:16:39,833 --> 00:16:42,600 ♪ 313 00:16:42,633 --> 00:16:46,866 PACALA: A good example is aviation. 314 00:16:46,900 --> 00:16:49,566 WURZBACHER: You couldn't build today a commercial airplane 315 00:16:49,600 --> 00:16:52,800 {\an1}for long distances which could fly on batteries. 316 00:16:52,833 --> 00:16:54,333 {\an1}You would just carry way too much weight. 317 00:16:56,100 --> 00:16:58,766 STEINFELD: This is physically impossible. 318 00:16:58,800 --> 00:17:02,300 There is no way around jet fuel. 319 00:17:02,333 --> 00:17:04,266 ♪ 320 00:17:04,300 --> 00:17:08,066 LONG: We need to be producing fuel that, when you burn that fuel, 321 00:17:08,100 --> 00:17:10,400 it doesn't emit carbon dioxide. 322 00:17:10,433 --> 00:17:13,766 {\an1}Remo, go ahead and rotate. 323 00:17:13,800 --> 00:17:16,366 NARRATOR: Aldo Steinfeld thinks he's found a way. 324 00:17:16,400 --> 00:17:21,300 ♪ 325 00:17:21,333 --> 00:17:23,800 STEINFELD: Perfect. We are on target. 326 00:17:28,600 --> 00:17:32,966 We have demonstrated that we canproduce liquid hydrocarbon fuels 327 00:17:33,000 --> 00:17:34,633 {\an1}from two ingredients. 328 00:17:37,466 --> 00:17:40,100 Sunlight 329 00:17:40,133 --> 00:17:43,233 and ambient air. 330 00:17:43,266 --> 00:17:46,966 ♪ 331 00:17:47,000 --> 00:17:49,766 (whirring) 332 00:17:49,800 --> 00:17:53,800 {\an1}It may sound like science fiction or magic... 333 00:17:53,833 --> 00:17:55,700 (whirring) 334 00:17:55,733 --> 00:17:57,366 {\an1}But it is chemistry, 335 00:17:57,400 --> 00:17:59,033 {\an1}it is heat transfer, 336 00:17:59,066 --> 00:18:02,100 {\an1}and also, it's a lot of engineering. 337 00:18:02,133 --> 00:18:04,933 ♪ 338 00:18:04,966 --> 00:18:09,200 NARRATOR: Aldo captures CO2 and water from the air 339 00:18:09,233 --> 00:18:12,300 {\an1}and feeds them into a solar reactor. 340 00:18:12,333 --> 00:18:15,700 STEINFELD: Solar radiation is reflected 341 00:18:15,733 --> 00:18:20,266 {\an1}and concentrated at the focus by a factor of 5,000. 342 00:18:20,300 --> 00:18:23,366 {\an7}It is like the intensity of 5,000 suns. 343 00:18:23,400 --> 00:18:26,400 NARRATOR: Concentrated solar energy 344 00:18:26,433 --> 00:18:29,433 drives a reaction that generates a synthetic gas, 345 00:18:29,466 --> 00:18:33,200 {\an1}which can then be converted into fuels. 346 00:18:33,233 --> 00:18:36,366 {\an7}And here in my hands, I have an example of 347 00:18:36,400 --> 00:18:39,200 solar methanol. 348 00:18:39,233 --> 00:18:42,600 ♪ 349 00:18:42,633 --> 00:18:43,900 NARRATOR: When it's burned, 350 00:18:43,933 --> 00:18:46,800 {\an1}the carbon in this fuel returns to the atmosphere. 351 00:18:46,833 --> 00:18:53,000 {\an1}But since it was harvested there, the net CO2 is zero. 352 00:18:53,033 --> 00:18:54,366 {\an1}This is called carbon-neutral, 353 00:18:54,400 --> 00:18:58,266 {\an1}and hundreds of scientists like Aldo are working to make 354 00:18:58,300 --> 00:19:02,066 {\an1}carbon-neutral fuels a reality. 355 00:19:04,400 --> 00:19:07,200 If they succeed,annual net emissions would drop 356 00:19:07,233 --> 00:19:10,733 by as much as one billion tons. 357 00:19:10,766 --> 00:19:15,066 {\an1}It's going to be something revolutionary. 358 00:19:16,633 --> 00:19:20,633 NARRATOR: But with these fuels up to sixtimes the cost of standard fuel, 359 00:19:20,666 --> 00:19:26,566 {\an1}it's a revolution that has only just begun. 360 00:19:26,600 --> 00:19:28,666 {\an1}But it raises the question: 361 00:19:28,700 --> 00:19:33,666 {\an1}what else can we make by recycling CO2? 362 00:19:33,700 --> 00:19:36,366 DENNING: Carbon is this incredible building block. 363 00:19:36,400 --> 00:19:37,633 Think of it like 364 00:19:37,666 --> 00:19:40,200 {\an1}those little sort of Lego toys that we used to have, 365 00:19:40,233 --> 00:19:42,533 {\an1}only there's four little plug-ins for it. 366 00:19:42,566 --> 00:19:46,033 {\an1}So you could bond carbon to carbon to carbon to carbon 367 00:19:46,066 --> 00:19:49,133 {\an1}to build all kinds of stuff. 368 00:19:49,166 --> 00:19:51,266 MAN: Imagine a world where everything around you 369 00:19:51,300 --> 00:19:53,400 {\an1}is made from carbon emissions, 370 00:19:53,433 --> 00:19:55,300 {\an1}from the products you use everyday 371 00:19:55,333 --> 00:19:56,866 {\an1}to the clothes you wear. 372 00:19:56,900 --> 00:19:59,300 NARRATOR: This ad from the XPrize Foundation pitches 373 00:19:59,333 --> 00:20:03,266 {\an1}a future where recycled CO2 shapes our world-- 374 00:20:03,300 --> 00:20:07,900 {\an1}and a $20 million bounty to make that a reality. 375 00:20:07,933 --> 00:20:10,200 {\an7}We announced, "Hey, there's a $20 million prize out there, 376 00:20:10,233 --> 00:20:12,466 {\an7}"we're looking for innovators around the world. 377 00:20:12,500 --> 00:20:14,966 {\an7}"If you know how to convert CO2 into a useful material, 378 00:20:15,000 --> 00:20:16,166 {\an7}consider entering this prize." 379 00:20:16,200 --> 00:20:19,766 {\an8}♪ 380 00:20:19,800 --> 00:20:21,200 {\an7}We are trying to help catalyze the whole ecosystem 381 00:20:21,233 --> 00:20:23,500 {\an7}of companies, of investors, 382 00:20:23,533 --> 00:20:25,633 {\an7}of people that can deploy these technologies. 383 00:20:25,666 --> 00:20:30,266 {\an8}♪ 384 00:20:30,300 --> 00:20:35,500 {\an8}NARRATOR: The Carbon XPrize has brought five of the finalists here 385 00:20:35,533 --> 00:20:38,100 {\an7}to put their innovations to the test. 386 00:20:38,133 --> 00:20:44,133 {\an7}They're setting up shop next to a plentiful supply of CO2. 387 00:20:44,166 --> 00:20:45,833 EXTAVOUR: They've got to take the emissions 388 00:20:45,866 --> 00:20:47,200 {\an1}from a natural gas power plant 389 00:20:47,233 --> 00:20:49,766 {\an1}and convert those into whatever material they like. 390 00:20:49,800 --> 00:20:53,066 {\an8}NARRATOR: From toothpaste... 391 00:20:53,100 --> 00:20:55,366 {\an8}to yoga mats... 392 00:20:55,400 --> 00:20:57,233 {\an8}to watches. 393 00:20:57,266 --> 00:21:02,166 {\an1}Each team will be scored on its net CO2 reduction. 394 00:21:02,200 --> 00:21:03,533 EXTAVOUR: You could have a process 395 00:21:03,566 --> 00:21:05,233 that uses up a lot of CO2to make its product, 396 00:21:05,266 --> 00:21:08,400 {\an1}but in the end, just produces more CO2 than it uses up. 397 00:21:08,433 --> 00:21:09,366 Okay. 398 00:21:09,400 --> 00:21:10,733 {\an1}We don't want that. Yup. 399 00:21:10,766 --> 00:21:12,666 {\an1}We want things that actually are reducing CO2 overall. 400 00:21:12,700 --> 00:21:14,733 ♪ 401 00:21:14,766 --> 00:21:17,833 SINHA: We just moved to site about two weeks ago. 402 00:21:17,866 --> 00:21:19,666 A day later, and I think we'd have 403 00:21:19,700 --> 00:21:22,233 (chuckling): snow in here that we'd be shoveling out, so... 404 00:21:22,266 --> 00:21:27,866 {\an8}NARRATOR: Apoorv Sinha is the C.E.O. of Carbon Upcycling Technologies, 405 00:21:27,900 --> 00:21:30,300 {\an8}or CUT. 406 00:21:30,333 --> 00:21:33,266 {\an1}We're a carbon tech company which takes carbon emissions 407 00:21:33,300 --> 00:21:36,333 {\an1}and converts them into solid nanomaterial products 408 00:21:36,366 --> 00:21:38,966 {\an1}for use in anything from cutlery to car parts. 409 00:21:39,000 --> 00:21:40,700 ♪ 410 00:21:40,733 --> 00:21:45,333 NARRATOR: But to make the biggest impacton CO2 and win this competition, 411 00:21:45,366 --> 00:21:49,266 Apoorv is focused on cement. 412 00:21:49,300 --> 00:21:53,000 Cement is an essential component of concrete-- 413 00:21:53,033 --> 00:21:54,733 {\an1}the glue that binds it together. 414 00:21:57,466 --> 00:22:02,033 {\an1}But producing it creates a lot of CO2. 415 00:22:02,066 --> 00:22:03,566 SINHA: Cement production accounts 416 00:22:03,600 --> 00:22:06,500 {\an1}for over eight percent of the world's annual emissions. 417 00:22:06,533 --> 00:22:09,900 {\an1}If all the cement-producing companies were a country, 418 00:22:09,933 --> 00:22:13,100 {\an1}they would be the third-largest emitter in the world. 419 00:22:13,133 --> 00:22:16,200 ♪ 420 00:22:16,233 --> 00:22:17,866 NARRATOR: Apoorv's process converts CO2 421 00:22:17,900 --> 00:22:20,100 {\an1}into a needed ingredient for concrete. 422 00:22:20,133 --> 00:22:22,966 {\an1}And he believes it will also 423 00:22:23,000 --> 00:22:28,033 {\an1}reduce the amount of cement that concrete manufacturers need. 424 00:22:28,066 --> 00:22:30,300 {\an1}He starts with an industrial waste powder 425 00:22:30,333 --> 00:22:32,100 {\an1}left over from burning coal 426 00:22:32,133 --> 00:22:34,766 called fly ash. 427 00:22:34,800 --> 00:22:36,600 With the reactor that we have behind us, 428 00:22:36,633 --> 00:22:38,800 we're scaling up and commercializing 429 00:22:38,833 --> 00:22:41,666 {\an1}an enhanced fly ash, where the fly ash has been 430 00:22:41,700 --> 00:22:43,400 {\an1}chemically activated to capture CO2. 431 00:22:46,100 --> 00:22:50,033 {\an1}As the reactor spins the fly ash, we inject CO2. 432 00:22:50,066 --> 00:22:52,800 {\an1}Ball bearings coated with a catalyst 433 00:22:52,833 --> 00:22:55,266 {\an1}speed up the chemical reaction. 434 00:22:55,300 --> 00:22:58,433 {\an1}As the ball bearings rise and fall, 435 00:22:58,466 --> 00:23:00,533 {\an1}the motion breaks up the fly ash 436 00:23:00,566 --> 00:23:05,100 {\an1}and roughs up the surface, so that more CO2 can be absorbed. 437 00:23:05,133 --> 00:23:08,100 NARRATOR: As the CO2 penetrates the fly ash surface, 438 00:23:08,133 --> 00:23:11,233 it forges tunnels along the way. 439 00:23:11,266 --> 00:23:15,200 {\an1}In effect, carbondioxide has bonded with fly ash 440 00:23:15,233 --> 00:23:20,333 {\an1}to create a nanoparticlewith more reactive surface area, 441 00:23:20,366 --> 00:23:22,933 which can bind concrete together 442 00:23:22,966 --> 00:23:25,500 {\an1}and strengthen it with less cement. 443 00:23:25,533 --> 00:23:29,033 SINHA: If concrete producers are able to use less cement 444 00:23:29,066 --> 00:23:31,600 in their production, they could considerably reduce 445 00:23:31,633 --> 00:23:34,266 {\an1}the emissions that come from their industry. 446 00:23:34,300 --> 00:23:36,100 NARRATOR: The question remains: 447 00:23:36,133 --> 00:23:40,266 {\an1}is it strong enough for concrete makers to buy it? 448 00:23:40,300 --> 00:23:42,033 {\an1}We just want to make sure that the technology is good, 449 00:23:42,066 --> 00:23:43,566 {\an1}and that it works really well. 450 00:23:43,600 --> 00:23:46,666 SINHA: One of our local partnersis a family-owned Calgary-based 451 00:23:46,700 --> 00:23:49,000 concrete business called Burnco. 452 00:23:51,533 --> 00:23:55,133 {\an8}NARRATOR: Burnco is testing the strength of concrete held together 453 00:23:55,166 --> 00:23:58,266 {\an1}using Apoorv's nanoparticle. 454 00:23:58,300 --> 00:24:00,966 ♪ 455 00:24:01,000 --> 00:24:02,266 MAN:When the cylinder breaks, 456 00:24:02,300 --> 00:24:04,333 we will have our final pressure read up there. 457 00:24:04,366 --> 00:24:09,833 ♪ 458 00:24:09,866 --> 00:24:13,033 NORM KUNTZ: These are impressive results. 459 00:24:13,066 --> 00:24:14,966 {\an7}In normal production, you're looking for changes 460 00:24:15,000 --> 00:24:18,066 {\an7}of three to four percent, and these are showing 461 00:24:18,100 --> 00:24:20,233 {\an7}results in, in double digits, 462 00:24:20,266 --> 00:24:21,800 {\an1}which is very encouraging. 463 00:24:21,833 --> 00:24:23,733 ♪ 464 00:24:23,766 --> 00:24:26,033 SINHA: We're very confident that we can get 465 00:24:26,066 --> 00:24:27,033 {\an1}up to a ten percent reduction 466 00:24:27,066 --> 00:24:29,733 {\an1}in the amount of cement used today. 467 00:24:29,766 --> 00:24:32,700 {\an1}But our real target is to get that number up to 20% or 25%. 468 00:24:32,733 --> 00:24:35,000 ♪ 469 00:24:35,033 --> 00:24:37,666 {\an1}Then we start talking aboutsignificantly moving the needle 470 00:24:37,700 --> 00:24:41,300 {\an1}on the 37-gigaton-a-year number. 471 00:24:42,600 --> 00:24:45,433 NARRATOR: But even if these new technologies can scale 472 00:24:45,466 --> 00:24:47,733 {\an1}to their full potential, 473 00:24:47,766 --> 00:24:51,166 {\an1}they could only lock away a fraction of our emissions. 474 00:24:52,833 --> 00:24:55,833 KEITH: The total volume of CO2that we create in the atmosphere 475 00:24:55,866 --> 00:24:59,100 {\an1}is so much biggerthan the volume of any product. 476 00:24:59,133 --> 00:25:01,866 {\an1}I think people are losing track of the central issue, 477 00:25:01,900 --> 00:25:04,600 {\an7}which is, we have to reduce net CO2 emissions. 478 00:25:07,566 --> 00:25:08,800 {\an8}DENNING: The easiest thing, 479 00:25:08,833 --> 00:25:12,000 {\an7}believe it or not, is to burn less carbon, right? 480 00:25:12,033 --> 00:25:14,633 {\an7}To, to not generate the CO2 in the first place. 481 00:25:14,666 --> 00:25:20,566 NARRATOR: Carbon-free energy like wind, solar, and nuclear power 482 00:25:20,600 --> 00:25:23,700 {\an1}can drive down most of our annual emissions. 483 00:25:23,733 --> 00:25:25,433 {\an1}And the rest could be offset 484 00:25:25,466 --> 00:25:27,900 {\an1}with negative-emissions technologies 485 00:25:27,933 --> 00:25:31,133 {\an1}that remove CO2 from the air. 486 00:25:31,166 --> 00:25:32,966 {\an8}KEITH: We will do it. 487 00:25:33,000 --> 00:25:35,966 {\an7}We will get to the day--there'll be global celebrations 488 00:25:36,000 --> 00:25:37,800 {\an7}when we get to net zero day, 489 00:25:37,833 --> 00:25:42,066 {\an7}where we brought human CO2 emissions to zero. 490 00:25:42,100 --> 00:25:43,733 {\an1}I think it'll happen in my lifetime. 491 00:25:43,766 --> 00:25:44,800 It is doable. 492 00:25:44,833 --> 00:25:45,833 But on that day, 493 00:25:45,866 --> 00:25:48,633 {\an1}we have not solved the climate problem. 494 00:25:48,666 --> 00:25:51,566 All we've done is stop making it worse. 495 00:25:51,600 --> 00:25:53,033 ♪ 496 00:25:53,066 --> 00:25:56,900 NARRATOR: The problem that remains is heat. 497 00:25:56,933 --> 00:26:00,333 ♪ 498 00:26:00,366 --> 00:26:02,233 DENNING: The temperature of the Earthis determined by heat coming in 499 00:26:02,266 --> 00:26:03,400 from the sun 500 00:26:03,433 --> 00:26:06,100 {\an1}and heat going out by radiation out to space. 501 00:26:06,133 --> 00:26:09,200 ♪ 502 00:26:09,233 --> 00:26:12,566 NARRATOR: Every single day, CO2 from our past emissions 503 00:26:12,600 --> 00:26:15,566 traps energy in the Earth's system-- 504 00:26:15,600 --> 00:26:19,966 {\an1}the same amount of energy as 500,000 of the bomb 505 00:26:20,000 --> 00:26:24,166 {\an1}dropped on Hiroshima detonating at once. 506 00:26:24,200 --> 00:26:27,333 {\an1}That heat is altering our climate. 507 00:26:27,366 --> 00:26:29,533 {\an1}What's it going to be like when, you know, 508 00:26:29,566 --> 00:26:32,600 {\an7}three months of the year are 115 degrees? 509 00:26:35,166 --> 00:26:40,166 {\an7}When vast ecosystems have died out? 510 00:26:40,200 --> 00:26:44,400 {\an7}People are going to push for,for doing something about this. 511 00:26:44,433 --> 00:26:48,866 {\an8}NARRATOR: And many fear Earth is approaching a tipping point 512 00:26:48,900 --> 00:26:51,466 {\an8}that will trigger rapid change. 513 00:26:51,500 --> 00:26:55,533 {\an8}PACALA: The uncertainties that keep me up at night are, 514 00:26:55,566 --> 00:26:56,966 {\an8}what if we aren't doing enough, 515 00:26:57,000 --> 00:27:00,133 {\an8}and there's some monster lurking behind the door 516 00:27:00,166 --> 00:27:01,500 {\an1}that all of a sudden comes 517 00:27:01,533 --> 00:27:03,566 {\an1}out into the world among us? 518 00:27:03,600 --> 00:27:07,533 ♪ 519 00:27:11,800 --> 00:27:13,933 {\an1}It's a good idea that humanity 520 00:27:13,966 --> 00:27:16,900 {\an8}has some sort of a backstop technology, 521 00:27:16,933 --> 00:27:20,900 {\an7}something to do if we get surprised in a way 522 00:27:20,933 --> 00:27:22,233 {\an1}that is very, very dangerous. 523 00:27:25,200 --> 00:27:30,200 NARRATOR: Some think that backstop could be solar geoengineering. 524 00:27:30,233 --> 00:27:34,266 PACALA:It's a way to intercept sunlight coming into the planet 525 00:27:34,300 --> 00:27:37,633 {\an1}to cool the planet. 526 00:27:37,666 --> 00:27:41,666 KEITH: The core idea is that humans might deliberately alter 527 00:27:41,700 --> 00:27:44,800 {\an1}the Earth's energy balance to compensate for 528 00:27:44,833 --> 00:27:47,100 {\an1}some of the warming and climate changes 529 00:27:47,133 --> 00:27:49,000 {\an1}that come from greenhouse gases. 530 00:27:49,033 --> 00:27:51,233 ♪ 531 00:27:51,266 --> 00:27:56,833 NARRATOR:Geoengineering the climate is a controversial idea. 532 00:27:56,866 --> 00:28:00,933 {\an1}But nature can show us examples of where we might start-- 533 00:28:00,966 --> 00:28:02,766 clouds. 534 00:28:02,800 --> 00:28:07,333 SARAH DOHERTY: A cloud is just water that's condensed down onto particles 535 00:28:07,366 --> 00:28:09,233 {\an1}into small droplets. 536 00:28:09,266 --> 00:28:13,366 NARRATOR: These collections of droplets are, in effect, 537 00:28:13,400 --> 00:28:16,500 {\an1}floating sun reflectors. 538 00:28:16,533 --> 00:28:20,133 {\an7}Clouds play a huge role in controlling the climate 539 00:28:20,166 --> 00:28:22,533 {\an7}because they control the reflectivity of the planet. 540 00:28:25,500 --> 00:28:27,400 {\an1}Especially over the ocean, 541 00:28:27,433 --> 00:28:30,400 {\an1}you go from sunlight hitting a very dark surface, 542 00:28:30,433 --> 00:28:32,400 {\an1}where a lot of the sunlight is absorbed, 543 00:28:32,433 --> 00:28:35,466 {\an1}to sunlight hitting an extremely bright surface, 544 00:28:35,500 --> 00:28:38,533 {\an1}reflecting a lot of that sunlight back to space. 545 00:28:38,566 --> 00:28:43,566 NARRATOR: Sarah Doherty of theMarine Cloud Brightening Project 546 00:28:43,600 --> 00:28:46,566 {\an1}is working on a way to boost that effect. 547 00:28:46,600 --> 00:28:50,066 DOHERTY:Can we add really small sea salt particles to clouds 548 00:28:50,100 --> 00:28:53,333 {\an1}in a way that significantly increases their brightness, 549 00:28:53,366 --> 00:28:57,066 {\an1}and do so over enough of the ocean that we would have 550 00:28:57,100 --> 00:28:59,600 {\an1}a significant impact on the global temperature? 551 00:29:01,433 --> 00:29:04,566 NARRATOR: But how do you make saltwater particles 552 00:29:04,600 --> 00:29:07,366 and launch them up into clouds? 553 00:29:08,933 --> 00:29:10,833 DOHERTY: What we need is a nozzle 554 00:29:10,866 --> 00:29:12,833 {\an1}like you'd see in a sort of a snowblower, 555 00:29:12,866 --> 00:29:15,066 {\an1}except that the particles that we want to produce are about 556 00:29:15,100 --> 00:29:16,800 {\an1}a thousandth the width of a human hair. 557 00:29:16,833 --> 00:29:19,800 (humming) 558 00:29:20,933 --> 00:29:23,566 NARRATOR: So Sarah's working with an engineer 559 00:29:23,600 --> 00:29:25,100 {\an1}who knows all about machines 560 00:29:25,133 --> 00:29:28,133 for spraying super-fine droplets-- 561 00:29:28,166 --> 00:29:32,833 {\an1}a concept developer of the earliest inkjet printers. 562 00:29:32,866 --> 00:29:38,266 {\an1}ARMAND NEUKERMANS: In a different life, I was an engineer and a physicist. 563 00:29:38,300 --> 00:29:41,966 {\an7}I couldn't enjoy retirement anymore and just sit there 564 00:29:42,000 --> 00:29:43,333 {\an7}and watch what's going on. 565 00:29:43,366 --> 00:29:46,733 {\an7}Once you know what's going to happen or might happen, 566 00:29:46,766 --> 00:29:48,300 {\an7}you can't sit down and say, 567 00:29:48,333 --> 00:29:49,833 {\an1}"Yeah, I'm just going to enjoy life." 568 00:29:51,266 --> 00:29:54,633 NARRATOR: Armand and his team of retired scientists 569 00:29:54,666 --> 00:29:56,766 {\an1}have been developing a cloud-brightening machine 570 00:29:56,800 --> 00:29:58,733 {\an1}for over ten years. 571 00:29:58,766 --> 00:30:03,833 MURPHY:They have been self-funding thisresearch in borrowed lab space. 572 00:30:03,866 --> 00:30:06,766 {\an7}PARC is a really good place for them 573 00:30:06,800 --> 00:30:08,766 {\an7}because of our history with aerosols. 574 00:30:08,800 --> 00:30:12,666 {\an8}NARRATOR: PARC, or Palo Alto Research Center, 575 00:30:12,700 --> 00:30:15,433 {\an1}has infused the Marine Cloud Brightening Project 576 00:30:15,466 --> 00:30:18,500 {\an1}with fresh expertise and cutting-edge tools. 577 00:30:18,533 --> 00:30:21,866 {\an1}Here, Kate Murphy can make aerosols 578 00:30:21,900 --> 00:30:24,433 {\an1}from just about anything. 579 00:30:24,466 --> 00:30:26,933 {\an7}This is our deep conditioner. 580 00:30:26,966 --> 00:30:31,766 NARRATOR: Aerosols are tiny particles suspended in air. 581 00:30:31,800 --> 00:30:32,966 This is ketchup. 582 00:30:33,000 --> 00:30:37,200 {\an1}(machine whirring) 583 00:30:37,233 --> 00:30:40,700 NARRATOR:For clouds, they're not going to spray ketchup. 584 00:30:41,766 --> 00:30:43,333 {\an1}But Kate can help the team 585 00:30:43,366 --> 00:30:46,400 {\an1}design a nozzle for spraying saltwater. 586 00:30:46,433 --> 00:30:48,633 {\an1}Let me just give it a little water, okay? 587 00:30:48,666 --> 00:30:50,433 MURPHY: Okay. 588 00:30:50,466 --> 00:30:52,766 NARRATOR: Kate's expertise will help optimize 589 00:30:52,800 --> 00:30:54,666 {\an1}the size and speed of the particles 590 00:30:54,700 --> 00:30:57,966 {\an1}to propel them into marine clouds. 591 00:30:58,000 --> 00:31:00,966 SUDHANSHU JAIN: So you're going to be redesigning the nozzle 592 00:31:01,000 --> 00:31:03,333 {\an1}based on your computational fluid dynamics? 593 00:31:03,366 --> 00:31:04,766 {\an1}Well, we hope to be able to understand the effect 594 00:31:04,800 --> 00:31:05,966 of multiple nozzles, 595 00:31:06,000 --> 00:31:07,066 {\an1}so we would want to measure things 596 00:31:07,100 --> 00:31:09,766 {\an1}like velocity and direction. 597 00:31:11,066 --> 00:31:13,900 NARRATOR: These crisscrossed laser beams can help reveal 598 00:31:13,933 --> 00:31:17,633 {\an1}whether Armand's nozzle will hit the mark. 599 00:31:17,666 --> 00:31:19,366 MURPHY: The lasers are at power. 600 00:31:19,400 --> 00:31:21,866 {\an1}Um, it looks like our signal's pretty good. 601 00:31:21,900 --> 00:31:24,500 {\an1}NEUKERMANS:So can you measure thevertical velocity? 602 00:31:24,533 --> 00:31:26,100 {\an1}Do you have a measurementof that? Yes. 603 00:31:26,133 --> 00:31:27,900 That would beof great interest to us. 604 00:31:27,933 --> 00:31:31,966 DOHERTY: PARC will be working ondeveloping a full spray system. 605 00:31:32,000 --> 00:31:33,400 {\an1}And then we would want to move outside, 606 00:31:33,433 --> 00:31:36,066 {\an1}into real atmospheric conditions. 607 00:31:37,766 --> 00:31:40,033 NARRATOR:On the other side of the world, 608 00:31:40,066 --> 00:31:43,100 {\an7}outdoor research has already begun. 609 00:31:43,133 --> 00:31:46,133 {\an8}♪ 610 00:31:46,166 --> 00:31:47,566 {\an8}Armand and the team have shared 611 00:31:47,600 --> 00:31:50,200 {\an8}their insights with researchers in Australia 612 00:31:50,233 --> 00:31:52,466 {\an1}who are testing cloud brightening as a way to cool 613 00:31:52,500 --> 00:31:55,200 {\an1}the waters surrounding the threatened coral of the reef. 614 00:31:55,233 --> 00:31:57,733 ♪ 615 00:31:57,766 --> 00:32:00,833 {\an1}That project is targeted and local, 616 00:32:00,866 --> 00:32:05,666 {\an1}but some estimate that cloud brightening on a global scale 617 00:32:05,700 --> 00:32:11,166 {\an7}could offset all the heat trapped by our CO2 emissions. 618 00:32:11,200 --> 00:32:13,600 {\an8}DOHERTY: It will probably take a good 15 to 20 years 619 00:32:13,633 --> 00:32:16,600 {\an1}to do all of the research involved with understanding 620 00:32:16,633 --> 00:32:19,533 {\an1}how big of an effect we can have by brightening clouds 621 00:32:19,566 --> 00:32:22,900 {\an1}and also what all of the side effects might be. 622 00:32:24,900 --> 00:32:27,433 NARRATOR: Those side effects are not well understood, 623 00:32:27,466 --> 00:32:29,400 {\an1}and could include disruptions 624 00:32:29,433 --> 00:32:31,800 to ecosystems and rainfall patterns. 625 00:32:31,833 --> 00:32:35,166 {\an1}Further research is needed. 626 00:32:35,200 --> 00:32:37,566 We have kids, we have grandkids... 627 00:32:37,600 --> 00:32:38,933 We're doing it for their futures. 628 00:32:38,966 --> 00:32:41,366 NEUKERMANS:You know, and frankly, 629 00:32:41,400 --> 00:32:44,033 we are all in this together,whether you have kids or not. 630 00:32:46,766 --> 00:32:48,433 NEUKERMANS: We're more than individuals. 631 00:32:48,466 --> 00:32:52,433 {\an1}Our society has to survive. 632 00:32:52,466 --> 00:32:55,566 ♪ 633 00:32:57,933 --> 00:33:01,733 NARRATOR: We're facing a problem that's getting worse, not better. 634 00:33:03,133 --> 00:33:07,900 {\an1}Do we need to consider more extreme measures? 635 00:33:07,933 --> 00:33:10,366 KEUTSCH: In 15 years or 20 years, 636 00:33:10,400 --> 00:33:13,033 {\an1}humanity may find itself at a point 637 00:33:13,066 --> 00:33:14,833 {\an7}where impacts are so big that 638 00:33:14,866 --> 00:33:17,200 {\an7}there's a very large demand for fast action. 639 00:33:18,800 --> 00:33:22,333 NARRATOR: To prepare, Frank Keutsch is starting now, 640 00:33:22,366 --> 00:33:26,766 {\an8}by researching a controversial technology 641 00:33:26,800 --> 00:33:29,900 {\an7}that goes further than brightening clouds. 642 00:33:29,933 --> 00:33:33,866 {\an1}It would brighten the entire planet. 643 00:33:33,900 --> 00:33:36,033 KEUTSCH: Putting particles in the stratosphere 644 00:33:36,066 --> 00:33:38,700 {\an1}could reflect back some sunlight to space, 645 00:33:38,733 --> 00:33:40,733 {\an1}reducing the amount of sunlight that hits the surface 646 00:33:40,766 --> 00:33:43,166 {\an1}and cooling down the planet. 647 00:33:43,200 --> 00:33:46,100 NARRATOR: The effect would be immediate. 648 00:33:46,133 --> 00:33:48,566 {\an1}(volcano erupting) 649 00:33:48,600 --> 00:33:50,833 PACALA: We know this works, 650 00:33:50,866 --> 00:33:52,500 {\an1}because every time a big volcano goes off 651 00:33:52,533 --> 00:33:54,866 {\an1}and it injects aerosols into the stratosphere, 652 00:33:54,900 --> 00:33:56,800 {\an1}the planet cools down. 653 00:33:58,466 --> 00:34:01,166 JASANOFF: That's the idea behind solar geoengineering. 654 00:34:01,200 --> 00:34:05,066 It's like drawing a curtain over the face of the Earth. 655 00:34:08,400 --> 00:34:09,800 KEUTSCH: The first time you hear about this, 656 00:34:09,833 --> 00:34:12,666 {\an1}you think, well, "That sounds like a really bad idea. 657 00:34:12,700 --> 00:34:14,366 {\an1}How could that not go wrong?" 658 00:34:17,566 --> 00:34:21,233 {\an1}But what we're doing to climate as humans, 659 00:34:21,266 --> 00:34:25,666 {\an1}that really to me starts seeming also quite scary, 660 00:34:25,700 --> 00:34:29,100 {\an1}and crazy, and really worrying. 661 00:34:29,133 --> 00:34:32,166 {\an7}The fact is, the CO2 is in the atmosphere. 662 00:34:32,200 --> 00:34:34,933 {\an7}Without a time machine, we can't make it go away. 663 00:34:36,633 --> 00:34:41,000 {\an1}We want to, in the long run, do carbon removal. 664 00:34:41,033 --> 00:34:43,800 {\an1}But during the time that concentrations are high, 665 00:34:43,833 --> 00:34:45,866 we might want to do solar geoengineering 666 00:34:45,900 --> 00:34:47,300 {\an1}to reduce the climate risk. 667 00:34:47,333 --> 00:34:51,000 {\an8}♪ 668 00:34:54,800 --> 00:34:56,433 KEITH:All that is hard-mounted to us. 669 00:34:56,466 --> 00:34:57,566 (group agreeing) 670 00:34:57,600 --> 00:34:59,100 That is exactly what I was... 671 00:34:59,133 --> 00:35:01,000 And then there's the balloon up there. 672 00:35:01,033 --> 00:35:03,366 NARRATOR: Frank and David's team is designing 673 00:35:03,400 --> 00:35:04,566 a first-of-its-kind experiment, 674 00:35:04,600 --> 00:35:06,500 called SCoPEx, 675 00:35:06,533 --> 00:35:10,066 {\an1}to investigate the impacts of solar geoengineering. 676 00:35:10,100 --> 00:35:12,800 {\an1}The only place I see that conversation getting sticky 677 00:35:12,833 --> 00:35:15,366 is where we do risk assessment on it. 678 00:35:15,400 --> 00:35:18,566 {\an8}KEUTSCH:If you put these particles out, 679 00:35:18,600 --> 00:35:20,733 {\an8}what happens when these come back down? 680 00:35:20,766 --> 00:35:22,800 {\an7}What happens when it gets into the environment? 681 00:35:22,833 --> 00:35:24,200 {\an1}Are we endangering people? 682 00:35:24,233 --> 00:35:26,866 KEITH: There are lots of things that we might need to know 683 00:35:26,900 --> 00:35:30,033 {\an1}where the existingexperimental background is bad. 684 00:35:30,066 --> 00:35:32,366 {\an1}You actually have to go out and make measurements. 685 00:35:32,400 --> 00:35:38,400 ♪ 686 00:35:38,433 --> 00:35:40,066 NARRATOR: The plan is to launch 687 00:35:40,100 --> 00:35:45,133 {\an1}a 100-foot balloon into the stratosphere 688 00:35:45,166 --> 00:35:47,200 and releasea plume of reflective aerosols. 689 00:35:50,266 --> 00:35:51,566 KEUTSCH: We want to put out 690 00:35:51,600 --> 00:35:54,333 the particles ofcalcium carbonate, for example, 691 00:35:54,366 --> 00:35:56,400 and then go back through this plume 692 00:35:56,433 --> 00:35:59,900 {\an8}and see whether the evolution of the air 693 00:35:59,933 --> 00:36:03,500 {\an1}is the way we predictedbased on our laboratory results. 694 00:36:05,566 --> 00:36:07,966 {\an1}This is an experiment on a very small scale. 695 00:36:08,000 --> 00:36:09,233 And in fact, 696 00:36:09,266 --> 00:36:10,533 {\an1}the amount of material we're putting out 697 00:36:10,566 --> 00:36:12,566 {\an1}is less than a normal airplane flight puts out. 698 00:36:14,466 --> 00:36:16,566 NARRATOR: SCoPEx may be small, 699 00:36:16,600 --> 00:36:18,866 but many fear a large-scale manipulation 700 00:36:18,900 --> 00:36:21,333 {\an1}of Earth's atmosphere could trigger 701 00:36:21,366 --> 00:36:23,100 {\an1}a cascade of dangerous, 702 00:36:23,133 --> 00:36:27,433 {\an1}unintended consequences that ripple across the planet. 703 00:36:27,466 --> 00:36:29,133 JASANOFF: Nothing in our scientific capability 704 00:36:29,166 --> 00:36:32,566 {\an1}actually enables us to understand the complexity 705 00:36:32,600 --> 00:36:35,533 {\an1}of the interactions that would be set loose. 706 00:36:35,566 --> 00:36:38,166 {\an7}It's not just that it lowers the temperature, 707 00:36:38,200 --> 00:36:39,733 {\an7}but what are some of the other effects 708 00:36:39,766 --> 00:36:41,233 {\an7}on the hydrologic cycle, 709 00:36:41,266 --> 00:36:43,900 {\an7}or on heat waves and droughts? 710 00:36:46,966 --> 00:36:49,900 JASANOFF: This is a manipulation of the Earth's atmosphere 711 00:36:49,933 --> 00:36:51,500 on a huge scale. 712 00:36:51,533 --> 00:36:53,333 What happens if things go wrong? 713 00:36:54,800 --> 00:36:56,566 NARRATOR: SCoPEx is designed to 714 00:36:56,600 --> 00:37:00,366 start answering those questions. 715 00:37:00,400 --> 00:37:03,366 {\an1}But there may be effects, beyond the physical, 716 00:37:03,400 --> 00:37:06,333 {\an1}that no experiment can predict. 717 00:37:06,366 --> 00:37:08,800 JASANOFF: If we think that there's this solution out there, 718 00:37:08,833 --> 00:37:10,200 {\an1}then people may think 719 00:37:10,233 --> 00:37:12,500 {\an1}it doesn't matter if you're polluting the planet. 720 00:37:12,533 --> 00:37:15,100 KEITH: The root of the concern 721 00:37:15,133 --> 00:37:16,633 {\an1}is that solar geoengineering research, 722 00:37:16,666 --> 00:37:19,166 {\an1}however well-intentioned, will be used as an excuse 723 00:37:19,200 --> 00:37:22,066 {\an1}for big fossil fuels to fight emissions cuts. 724 00:37:24,400 --> 00:37:27,466 DENNING: It's just like a sci-fi dystopian novel or something, 725 00:37:27,500 --> 00:37:28,533 {\an7}where we continue to just 726 00:37:28,566 --> 00:37:30,066 {\an7}belch all this CO2 into the atmosphere, 727 00:37:30,100 --> 00:37:32,233 {\an7}but hey, it's okay, because we got these little umbrellas 728 00:37:32,266 --> 00:37:37,666 {\an1}that are, you know, hiding us from the sun. 729 00:37:37,700 --> 00:37:40,000 KEITH: Solar geoengineering does not get us 730 00:37:40,033 --> 00:37:42,300 out of the ethical and physical 731 00:37:42,333 --> 00:37:44,000 {\an1}requirement to cut emissions. 732 00:37:46,133 --> 00:37:48,033 NARRATOR: But with so much uncertainty, 733 00:37:48,066 --> 00:37:49,333 {\an1}some think we're better off 734 00:37:49,366 --> 00:37:53,500 investing in a different kind of machine: 735 00:37:53,533 --> 00:37:55,966 one developed in nature's own laboratory 736 00:37:56,000 --> 00:38:00,533 {\an1}over millions of years, and with a proven record 737 00:38:00,566 --> 00:38:03,233 {\an1}of safely drawing down gigatons of CO2. 738 00:38:03,266 --> 00:38:06,766 Trees. 739 00:38:06,800 --> 00:38:08,233 (birds chirping) 740 00:38:12,800 --> 00:38:14,433 {\an8}FATOYINBO AGUEH: When I'm going on a hike through a forest, 741 00:38:14,466 --> 00:38:17,500 {\an1}I have a tendency to look up and say, 742 00:38:17,533 --> 00:38:19,766 {\an1}"Okay, oh, that tree's about 60 feet tall." 743 00:38:19,800 --> 00:38:21,833 {\an1}And then I try to calculate in my head, okay, 744 00:38:21,866 --> 00:38:24,933 {\an1}how much carbon is stored in that tree? 745 00:38:24,966 --> 00:38:26,900 {\an1}I think this is good. 746 00:38:27,966 --> 00:38:30,700 NARRATOR: Lola Fatoyinbo Agueh 747 00:38:30,733 --> 00:38:32,133 {\an1}is a research scientist 748 00:38:32,166 --> 00:38:33,633 at NASA's Goddard Space Flight Center. 749 00:38:33,666 --> 00:38:34,866 Sweet. It has power. 750 00:38:34,900 --> 00:38:36,266 {\an1}I love it when things work. 751 00:38:36,300 --> 00:38:39,266 NARRATOR: She and her team are about to see 752 00:38:39,300 --> 00:38:42,800 {\an1}these century-old trees in a new light. 753 00:38:42,833 --> 00:38:44,900 STOVALL:Green lights all around, if you want to do the honors. 754 00:38:44,933 --> 00:38:47,033 FATOYINBO AGUEH: There's carbon all around us. 755 00:38:47,066 --> 00:38:49,066 {\an7}If you think of trees as a machine, 756 00:38:49,100 --> 00:38:52,300 {\an7}then trees would be a carbon capture machine. 757 00:38:56,000 --> 00:38:57,900 {\an1}When we're looking at trees, 758 00:38:57,933 --> 00:39:00,766 {\an1}about half of that weight is carbon. 759 00:39:02,600 --> 00:39:04,600 NARRATOR: Lola and her team want to know 760 00:39:04,633 --> 00:39:09,633 {\an1}how much carbon is stored in this entire forest. 761 00:39:09,666 --> 00:39:12,300 {\an1}To measure each and every tree, 762 00:39:12,333 --> 00:39:14,633 they're using a special kind of tool... 763 00:39:16,500 --> 00:39:18,100 Lasers. 764 00:39:18,133 --> 00:39:19,600 FATOYINBO AGUEH: We're using a terrestrial laser scanner 765 00:39:19,633 --> 00:39:24,466 {\an1}that shoots out billions of laser pulses every second 766 00:39:24,500 --> 00:39:28,066 {\an1}and then measuresthe distance from the instrument 767 00:39:28,100 --> 00:39:30,466 {\an1}to whatever is around it. 768 00:39:30,500 --> 00:39:34,200 {\an1}The data that we get back generate a point cloud. 769 00:39:36,400 --> 00:39:38,333 {\an8}NARRATOR: Billions of data points 770 00:39:38,366 --> 00:39:40,666 {\an7}form a 3-D measurement of forest volume-- 771 00:39:40,700 --> 00:39:45,066 {\an7}and the carbon stored within. 772 00:39:45,100 --> 00:39:49,866 {\an8}FATOYINBO AGUEH: It's so dense that italmost looks like a photograph. 773 00:39:49,900 --> 00:39:53,500 {\an7}It's like science fiction. 774 00:39:53,533 --> 00:39:56,066 {\an8}NARRATOR:This scan may look like reality, 775 00:39:56,100 --> 00:40:00,333 {\an7}but this is data. 776 00:40:00,366 --> 00:40:04,466 {\an7}It reveals that in an area the size of a football field, 777 00:40:04,500 --> 00:40:07,400 {\an7}these trees are storing roughly 778 00:40:07,433 --> 00:40:09,566 {\an1}150 tons of carbon, 779 00:40:09,600 --> 00:40:11,900 {\an1}all pulled out of thin air. 780 00:40:11,933 --> 00:40:16,100 {\an1}Which prompts Tom Crowther to ask: 781 00:40:16,133 --> 00:40:20,133 {\an1}could we enlist trees in the race to draw down CO2? 782 00:40:20,166 --> 00:40:23,133 {\an8}♪ 783 00:40:23,166 --> 00:40:25,866 {\an8}CROWTHER: Our lab is urgently trying to figure out 784 00:40:25,900 --> 00:40:28,800 {\an7}how we increase the area of forest across the globe 785 00:40:28,833 --> 00:40:31,633 {\an7}to capture as much carbon as we possibly can 786 00:40:31,666 --> 00:40:33,333 {\an7}in the fight against climate change. 787 00:40:36,566 --> 00:40:40,466 NARRATOR: Tom's findings began with a surprising discovery. 788 00:40:40,500 --> 00:40:43,433 CROWTHER: We thought there was around400 billion trees on the planet. 789 00:40:45,000 --> 00:40:46,766 But we showed that 790 00:40:46,800 --> 00:40:50,400 {\an1}there is in fact around three trillion trees. 791 00:40:54,233 --> 00:40:56,800 {\an1}There's more trees on the surface of our planet 792 00:40:56,833 --> 00:40:58,866 than there are stars in the galaxy. 793 00:41:00,966 --> 00:41:03,200 NARRATOR: The big question is, 794 00:41:03,233 --> 00:41:05,100 {\an1}how many more trees could we add? 795 00:41:05,133 --> 00:41:08,133 {\an1}CONSTANTIN ZOHNER: In order to understand the global forest system, 796 00:41:08,166 --> 00:41:09,700 {\an1}we need to map a lot of things, 797 00:41:09,733 --> 00:41:11,033 {\an8}we need to know where forests are, 798 00:41:11,066 --> 00:41:11,966 {\an7}where forests could be. 799 00:41:12,000 --> 00:41:14,333 CROWTHER: We collect our data from 800 00:41:14,366 --> 00:41:16,433 {\an1}millions of locations around the world, 801 00:41:16,466 --> 00:41:18,700 {\an1}where scientists have been on the ground 802 00:41:18,733 --> 00:41:20,700 {\an1}evaluating those ecosystems. 803 00:41:22,200 --> 00:41:27,200 NARRATOR:Data like leaf fall patterns in forests around the world. 804 00:41:27,233 --> 00:41:29,600 {\an1}I'm trying to understand the seasonal rhythm of plants. 805 00:41:31,333 --> 00:41:33,466 NARRATOR: Microscopic organisms like 806 00:41:33,500 --> 00:41:35,700 {\an1}the tiny worms that feed the soil beneath the trees. 807 00:41:35,733 --> 00:41:37,033 {\an1}JOHAN VAN DEN HOOGEN: In just this clearing, 808 00:41:37,066 --> 00:41:38,866 {\an7}there is millions and millions of nematodes 809 00:41:38,900 --> 00:41:40,033 {\an7}living in the soil. 810 00:41:42,233 --> 00:41:43,933 {\an8}NARRATOR: And decades of satellite data 811 00:41:43,966 --> 00:41:47,966 {\an8}on factors like rainfall and temperature. 812 00:41:48,000 --> 00:41:50,733 {\an7}When I look at ecosystems most of the time, 813 00:41:50,766 --> 00:41:52,166 {\an7}I'm looking from the top down. 814 00:41:54,166 --> 00:41:55,966 {\an8}CROWTHER: And with all of that data, 815 00:41:56,000 --> 00:42:00,333 {\an7}we can start to see the patterns across the globe. 816 00:42:01,800 --> 00:42:04,333 {\an7}Using remote sensing information from satellites 817 00:42:04,366 --> 00:42:07,500 {\an1}and machine learning technologies, 818 00:42:07,533 --> 00:42:10,800 {\an1}we can generate maps that can predict which regions 819 00:42:10,833 --> 00:42:15,233 {\an1}can support new trees and which ones cannot. 820 00:42:15,266 --> 00:42:18,766 This really is a data revolution. 821 00:42:18,800 --> 00:42:22,600 NARRATOR: The detail is astonishing. 822 00:42:22,633 --> 00:42:27,133 {\an1}And the potential for new forests is vast. 823 00:42:27,166 --> 00:42:29,233 CROWTHER: Outside of urban and agricultural areas, 824 00:42:29,266 --> 00:42:31,133 {\an1}there's room for about 825 00:42:31,166 --> 00:42:34,133 {\an1}2.5 billion acres of forest. 826 00:42:39,766 --> 00:42:41,566 ZOHNER: The area we identified equals 827 00:42:41,600 --> 00:42:44,733 the size of the United States. 828 00:42:44,766 --> 00:42:47,933 {\an1}So there is a huge area available for restoration. 829 00:42:48,900 --> 00:42:50,733 NARRATOR: Enough space for 830 00:42:50,766 --> 00:42:53,933 {\an1}1.2 trillion new trees, 831 00:42:53,966 --> 00:42:58,100 {\an1}all sucking CO2 out of the air. 832 00:42:58,133 --> 00:43:01,100 CROWTHER: If we were to restore a trillion trees, 833 00:43:01,133 --> 00:43:03,766 {\an1}the right types of trees in the right kinds of soils, 834 00:43:03,800 --> 00:43:06,666 {\an1}and have them grow to full health, 835 00:43:06,700 --> 00:43:10,900 {\an1}they could store an additional 205 gigatons of carbon. 836 00:43:10,933 --> 00:43:13,966 NARRATOR: To put that into context, 837 00:43:14,000 --> 00:43:15,366 {\an1}we've released nearly 838 00:43:15,400 --> 00:43:18,666 {\an1}660 gigatons of carbon into Earth's systems 839 00:43:18,700 --> 00:43:23,233 {\an1}since human industrial activity began. 840 00:43:23,266 --> 00:43:25,566 CROWTHER: Restoring global forests 841 00:43:25,600 --> 00:43:28,966 and conserving the vital forests that we currently have 842 00:43:29,000 --> 00:43:32,933 {\an1}could take a huge chunk out of that excess carbon. 843 00:43:32,966 --> 00:43:37,933 {\an1}This is a really massive carbon drawdown solution. 844 00:43:37,966 --> 00:43:40,833 {\an1}And we knew that this was going to make an enormous splash. 845 00:43:43,266 --> 00:43:46,600 NARRATOR: But these findings also made waves. 846 00:43:46,633 --> 00:43:48,466 {\an1}(wildlife chittering) 847 00:43:48,500 --> 00:43:53,033 FATOYINBO AGUEH: That study is causing a lot of debate. 848 00:43:53,066 --> 00:43:54,333 On the one hand, 849 00:43:54,366 --> 00:43:56,766 a lot of people are talking about 850 00:43:56,800 --> 00:43:59,933 the potential of restoration of forests. 851 00:43:59,966 --> 00:44:01,333 {\an1}On the other hand, 852 00:44:01,366 --> 00:44:05,200 {\an1}I would say, um, a lot of people are very upset about it. 853 00:44:05,233 --> 00:44:10,266 (bird cawing) 854 00:44:10,300 --> 00:44:12,433 {\an1}The uncertainty around the amount of carbon 855 00:44:12,466 --> 00:44:14,933 {\an1}that's stored in trees is so high 856 00:44:14,966 --> 00:44:18,666 {\an7}that we can't really make any informed recommendations 857 00:44:18,700 --> 00:44:21,066 {\an7}on how many trees we need to plant. 858 00:44:21,100 --> 00:44:26,000 NARRATOR: Lola wants to use new technology from NASA 859 00:44:26,033 --> 00:44:31,166 {\an1}to fill those areas of uncertainty with hard data. 860 00:44:31,200 --> 00:44:33,766 FATOYINBO AGUEH: We have over 20 Earth-observing satellites 861 00:44:33,800 --> 00:44:37,633 {\an1}right now from NASA alone looking at our planet Earth. 862 00:44:37,666 --> 00:44:40,266 {\an1}But what we're seeing is all in two dimensions. 863 00:44:40,300 --> 00:44:43,033 {\an1}What we're missing here is the third dimension. 864 00:44:44,200 --> 00:44:48,833 NARRATOR:Enter a powerful new tool called GEDI. 865 00:44:48,866 --> 00:44:50,566 {\an1}With the same laser technology 866 00:44:50,600 --> 00:44:53,533 used in her terrestrial scanners, 867 00:44:53,566 --> 00:44:56,233 Lola can get a three-dimensional measure of forest carbon 868 00:44:56,266 --> 00:45:00,233 from the International Space Station. 869 00:45:00,266 --> 00:45:01,400 FATOYINBO AGUEH: GEDI stands for 870 00:45:01,433 --> 00:45:04,166 {\an1}the Global Ecosystem Dynamics Investigation, 871 00:45:04,200 --> 00:45:05,966 {\an1}which is what you're seeing right here. 872 00:45:06,000 --> 00:45:08,533 {\an8}This is about the size of a fridge. 873 00:45:08,566 --> 00:45:11,666 {\an7}You can see the lasers shooting down 874 00:45:11,700 --> 00:45:13,566 {\an7}out of the bottom of the instrument 875 00:45:13,600 --> 00:45:15,333 {\an8}towards the surface of the planet. 876 00:45:17,400 --> 00:45:18,366 {\an1}We actually can see 877 00:45:18,400 --> 00:45:20,466 a full profile of plant materials. 878 00:45:24,166 --> 00:45:26,100 {\an1}The game-changer here is that 879 00:45:26,133 --> 00:45:28,666 {\an1}this is going to be, for the first time, 880 00:45:28,700 --> 00:45:31,566 {\an1}a near-global data set. 881 00:45:33,800 --> 00:45:35,633 NARRATOR: GEDI will give clearer insight 882 00:45:35,666 --> 00:45:39,833 {\an1}on the carbon new forests could store. 883 00:45:39,866 --> 00:45:42,733 {\an1}But equally important, it can pinpoint 884 00:45:42,766 --> 00:45:47,233 {\an1}the old forest carbon we must preserve. 885 00:45:47,266 --> 00:45:49,500 FATOYINBO AGUEH: Forests are really important 886 00:45:49,533 --> 00:45:56,033 {\an1}for our water supply, forests protect us from heat, 887 00:45:56,066 --> 00:45:57,633 forests breathe. 888 00:45:57,666 --> 00:46:03,600 {\an1}They breathe in some ways just like we do. 889 00:46:03,633 --> 00:46:04,766 {\an1}When you lose a lot of 890 00:46:04,800 --> 00:46:07,266 {\an1}the ecosystem services that forests provide, 891 00:46:07,300 --> 00:46:11,866 {\an1}that has a direct impact on the well-being of people. 892 00:46:14,233 --> 00:46:17,633 NARRATOR: But on an increasingly populated planet, 893 00:46:17,666 --> 00:46:23,333 {\an1}trees are not the only living things competing for land. 894 00:46:23,366 --> 00:46:26,400 {\an7}We already use all of our agricultural land 895 00:46:26,433 --> 00:46:27,766 {\an7}to feed our existing population, 896 00:46:27,800 --> 00:46:32,500 {\an1}and over the next 30 years,food demand is going to double. 897 00:46:32,533 --> 00:46:36,066 If you take land to solve the climate problem, 898 00:46:36,100 --> 00:46:39,300 {\an1}you create another problem. 899 00:46:39,333 --> 00:46:42,300 NARRATOR: So, is there a solution 900 00:46:42,333 --> 00:46:45,566 {\an1}that can solve more than one problem at a time? 901 00:46:45,600 --> 00:46:48,133 WHENDEE SILVER:Some people are looking at ways 902 00:46:48,166 --> 00:46:50,000 in which forests can help slow climate change. 903 00:46:50,033 --> 00:46:52,166 Our research is somewhat different 904 00:46:52,200 --> 00:46:54,866 in that we're looking at grasslands. 905 00:46:54,900 --> 00:46:58,100 I want to have enoughso that we can do experiments. 906 00:46:58,133 --> 00:47:02,033 NARRATOR: In California, Whendee Silver is looking for a way to 907 00:47:02,066 --> 00:47:04,566 {\an1}pull down CO2 right where 908 00:47:04,600 --> 00:47:06,633 {\an1}we grow our food-- 909 00:47:06,666 --> 00:47:08,766 {\an1}Earth's grasslands. 910 00:47:08,800 --> 00:47:13,300 SILVER: This is a classic, beautiful annual grassland. 911 00:47:13,333 --> 00:47:14,533 {\an1}Grasslands grow in places 912 00:47:14,566 --> 00:47:16,200 {\an1}where there's drought for part of the year. 913 00:47:16,233 --> 00:47:20,133 {\an1}And these grasses have developed 914 00:47:20,166 --> 00:47:21,900 great tools for getting water, 915 00:47:21,933 --> 00:47:25,800 particularly by growing more roots. 916 00:47:25,833 --> 00:47:30,066 And any time plants invest a lot of their energy into roots, 917 00:47:30,100 --> 00:47:31,933 {\an7}it's like injecting carbon into the soil. 918 00:47:34,633 --> 00:47:39,400 NARRATOR:But tilling releases that carbon and degrades the soil. 919 00:47:39,433 --> 00:47:41,700 {\an1}And producing our food 920 00:47:41,733 --> 00:47:44,733 {\an1}creates even more problems. 921 00:47:44,766 --> 00:47:46,800 SILVER: We all eat food every day. 922 00:47:46,833 --> 00:47:48,300 {\an1}We have to grow that food. 923 00:47:48,333 --> 00:47:50,466 {\an1}And we create a lot of organic waste in the process. 924 00:47:50,500 --> 00:47:53,000 (birds cawing) 925 00:47:53,033 --> 00:47:55,766 NARRATOR: When organic waste sits in a landfill 926 00:47:55,800 --> 00:47:56,933 or slurry pond, 927 00:47:56,966 --> 00:47:59,566 it creates an oxygen-deprived environment 928 00:47:59,600 --> 00:48:04,066 {\an1}favorable to certain microbes, which in turn produce methane, 929 00:48:04,100 --> 00:48:08,933 a greenhouse gas 34 times more potent than CO2. 930 00:48:08,966 --> 00:48:10,700 {\an1}We're trying to tackle three big problems: 931 00:48:10,733 --> 00:48:15,400 {\an1}waste, degrading soil health, and climate change. 932 00:48:15,433 --> 00:48:19,833 {\an1}We came up with something relatively simple: 933 00:48:19,866 --> 00:48:21,533 composting. 934 00:48:21,566 --> 00:48:22,533 NARRATOR: In composting, 935 00:48:22,566 --> 00:48:24,633 food waste is regularly turned, 936 00:48:24,666 --> 00:48:27,566 {\an1}adding oxygen to the mix and keeping the 937 00:48:27,600 --> 00:48:31,533 {\an1}methane-producing microbes at bay. 938 00:48:31,566 --> 00:48:34,800 SILVER: It creates this organic and nutrient-rich resource, 939 00:48:34,833 --> 00:48:37,933 like a slow-release fertilizer, that helps plants grow. 940 00:48:44,000 --> 00:48:46,933 NARRATOR: By turning a waste into a nutrient, 941 00:48:46,966 --> 00:48:49,633 {\an1}compost can boost plant growth 942 00:48:49,666 --> 00:48:54,033 {\an1}and potentially turn vaststretches of Earth's food crops 943 00:48:54,066 --> 00:48:58,566 {\an1}into a carbon-storing juggernaut. 944 00:48:58,600 --> 00:49:00,300 {\an1}(indistinct talking) 945 00:49:00,333 --> 00:49:02,200 {\an1}Can you grab that? 946 00:49:02,233 --> 00:49:03,466 SILVER: We now have ten years of data 947 00:49:03,500 --> 00:49:08,233 {\an1}showing that just a one-time dusting of compost 948 00:49:08,266 --> 00:49:09,733 {\an1}onto the soil surface 949 00:49:09,766 --> 00:49:13,466 {\an1}can have a long-term impact on plant growth 950 00:49:13,500 --> 00:49:17,233 {\an1}and increase carbon storage in soils. 951 00:49:17,266 --> 00:49:19,266 {\an8}NARRATOR: Whendee's research shows that 952 00:49:19,300 --> 00:49:21,233 {\an7}a single layer of compost 953 00:49:21,266 --> 00:49:25,366 {\an7}can increase plant growth by up to 78% 954 00:49:25,400 --> 00:49:30,866 {\an1}and increase soil carbon by up to 37% for three years. 955 00:49:33,033 --> 00:49:34,500 SILVER: The real challenge is 956 00:49:34,533 --> 00:49:38,000 to extrapolate from little tiny soil samples in the field 957 00:49:38,033 --> 00:49:43,433 to big chunks of California or the globe. 958 00:49:43,466 --> 00:49:45,766 {\an1}That's a huge challenge. 959 00:49:45,800 --> 00:49:48,966 ♪ 960 00:49:51,866 --> 00:49:53,900 NARRATOR: As the hunt for solutions 961 00:49:53,933 --> 00:49:56,366 continues in the decades ahead, 962 00:49:56,400 --> 00:49:58,800 {\an1}stopping our emissions remains 963 00:49:58,833 --> 00:50:02,866 {\an1}the most urgent challenge of today. 964 00:50:02,900 --> 00:50:06,533 KEITH:If we really didn't do anything to limit carbon emissions, 965 00:50:06,566 --> 00:50:10,333 {\an1}we would have climate changes as big as the changes 966 00:50:10,366 --> 00:50:12,933 from the glacial to interglacial state 967 00:50:12,966 --> 00:50:14,800 and do that in one human lifetime, 968 00:50:14,833 --> 00:50:16,733 {\an1}with huge potential impacts. 969 00:50:16,766 --> 00:50:18,166 {\an1}The more of a mess we make, 970 00:50:18,200 --> 00:50:19,633 {\an1}the bigger of a mess we'll have to clean up. 971 00:50:21,433 --> 00:50:24,266 {\an1}We today get to decide 972 00:50:24,300 --> 00:50:27,666 whether to continue along this path... 973 00:50:31,666 --> 00:50:33,666 {\an1}Or to dramatically shift 974 00:50:33,700 --> 00:50:37,866 our economy off of coal, oil, and gas. 975 00:50:37,900 --> 00:50:40,833 EXTAVOR: Every big transformative solution starts small. 976 00:50:40,866 --> 00:50:43,633 It starts with a couple of people talking. 977 00:50:43,666 --> 00:50:44,866 {\an7}They make a small version, 978 00:50:44,900 --> 00:50:46,600 {\an7}they make a bigger version, more people pile in. 979 00:50:49,200 --> 00:50:50,766 ZOHNER: This is one solution, 980 00:50:50,800 --> 00:50:52,700 but we need thousands of solutions 981 00:50:52,733 --> 00:50:54,666 {\an1}if we want to tackle climate change. 982 00:50:54,700 --> 00:50:57,000 SILVER: There's no one magic 983 00:50:57,033 --> 00:50:59,033 silver bullet that will solve this problem. 984 00:50:59,066 --> 00:51:02,700 SINHA:The main challenge that we have 985 00:51:02,733 --> 00:51:05,133 {\an1}is that these transitions don't happen overnight. 986 00:51:06,266 --> 00:51:08,766 {\an1}SNAEBJORNSDOTTIR: We have the tools already, 987 00:51:08,800 --> 00:51:10,666 but we really have to start moving. 988 00:51:12,500 --> 00:51:14,600 DENNING: We need better transportation systems. 989 00:51:14,633 --> 00:51:16,533 {\an1}We need solar power and wind power 990 00:51:16,566 --> 00:51:19,666 and water power, and probably nuclear power. 991 00:51:19,700 --> 00:51:21,433 {\an1}We need to plant trees. 992 00:51:21,466 --> 00:51:23,133 We need to manage our farms better. 993 00:51:23,166 --> 00:51:25,133 {\an1}We need direct air capture. 994 00:51:25,166 --> 00:51:27,266 I think we probably need it all. 995 00:51:29,533 --> 00:51:32,433 LONG: We have to start really looking at what can scale up 996 00:51:32,466 --> 00:51:37,100 {\an1}and be maintained-- for decades, if not centuries. 997 00:51:37,133 --> 00:51:38,866 {\an1}That's the challenge here. 998 00:51:38,900 --> 00:51:40,800 But it's anincredibly important challenge. 999 00:51:40,833 --> 00:51:44,466 ♪ 1000 00:51:44,500 --> 00:51:45,700 PACALA: 15 years ago, 1001 00:51:45,733 --> 00:51:47,733 no one would have predicted that 1002 00:51:47,766 --> 00:51:51,300 {\an1}the emissions in developed countries around the world 1003 00:51:51,333 --> 00:51:52,933 {\an1}would be dropping. 1004 00:51:55,066 --> 00:51:56,400 {\an1}Not fast enough yet, 1005 00:51:56,433 --> 00:51:58,800 {\an1}but that gives me hope 1006 00:51:58,833 --> 00:52:00,766 {\an1}and should give everyone hope 1007 00:52:00,800 --> 00:52:05,000 {\an1}that with the combined might of human ingenuity, 1008 00:52:05,033 --> 00:52:06,733 we can actually solve this problem. 1009 00:52:06,766 --> 00:52:09,733 ♪ 1010 00:52:16,900 --> 00:52:22,533 {\an8}♪ 1011 00:52:32,800 --> 00:52:37,000 {\an7}To order this program on DVD, visit ShopPBS 1012 00:52:37,033 --> 00:52:40,300 {\an7}or call 1-800-PLAY-PBS. 1013 00:52:40,333 --> 00:52:43,033 {\an7}Episodes of "NOVA" are available with Passport. 1014 00:52:43,066 --> 00:52:46,566 {\an7}"NOVA" is also available on Amazon Prime Video. 1015 00:52:46,600 --> 00:52:51,700 {\an8}♪ 1016 00:52:59,100 --> 00:53:04,266 {\an8}♪