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