WEBVTT - A Radical Approach to Climate Change 0:00:15.250 --> 0:00:28.890 Pushkin, you're listening to Brave New Planet, a podcast about 0:00:28.930 --> 0:00:33.130 amazing new technologies that could dramatically improve our world. Or 0:00:33.490 --> 0:00:36.050 if we don't make wise choices, could leave us a 0:00:36.050 --> 0:00:40.730 lot worse off. Utopia or dystopia. It's up to us. 0:00:49.890 --> 0:00:52.570 In the Zambales Mountains on the island of Luzon in 0:00:52.610 --> 0:00:57.570 the Philippines, there lies of volcano named Mount Pinatubo. For 0:00:57.770 --> 0:01:03.090 five centuries, it had lain dormant, but on Saturday June fifteenth, 0:01:03.170 --> 0:01:06.970 nineteen ninety one, it erupted, causing one of the most 0:01:07.050 --> 0:01:11.850 cataclysmic events of the twentieth century. Torrential rain has mixed 0:01:11.850 --> 0:01:15.650 with volcanic ash to form a gray mud covering vast 0:01:15.690 --> 0:01:18.530 areas of the northern Philippines. The ash falls up to 0:01:18.570 --> 0:01:23.770 seven hundred kilometers from Mount Pinatubo. Nearly twenty million tons 0:01:23.810 --> 0:01:27.850 of sulfur dioxide were hurled into the stratosphere. The effects 0:01:27.850 --> 0:01:30.970 of the eruption were felt around the world. In the 0:01:30.970 --> 0:01:35.450 following fifteen months, average global temperature dropped by roughly one 0:01:35.530 --> 0:01:40.610 degree fahrenheit. Why because the sulfur dioxide released by the 0:01:40.690 --> 0:01:45.210 volcano reflected back a fraction of the Sun's energy, preventing 0:01:45.210 --> 0:01:49.250 it from reaching the Earth. The notion that huge volcanos 0:01:49.330 --> 0:01:52.050 might affect the weather is actually an old one. Ben 0:01:52.170 --> 0:01:55.490 Franklin proposed that the severe winter of seventeen eighty three 0:01:55.570 --> 0:01:58.810 to eighty four was triggered by a massive eruption in 0:01:58.890 --> 0:02:03.650 Iceland the previous summer. In nineteen sixty five, inspired by 0:02:03.690 --> 0:02:08.810 the volcano theory, science advisors to President Lyndon Johnson proposed 0:02:08.810 --> 0:02:13.530 develop helping technology to pump sulfur dioxide into the stratosphere 0:02:13.930 --> 0:02:18.130 to offset global warming, but the idea didn't go far 0:02:18.770 --> 0:02:22.290 because they had no good way to test it. Then, 0:02:22.810 --> 0:02:27.650 in nineteen ninety one, Mount Pinatubo ran a test for US. 0:02:28.610 --> 0:02:32.850 It seemed to confirm the hypothesis. The proposal started to 0:02:32.890 --> 0:02:36.130 gain attention. Point is this, if the problem gets bad 0:02:36.210 --> 0:02:38.250 enough to do something about, well, don't you want to 0:02:38.290 --> 0:02:40.650 have something to do. The idea of that is to 0:02:40.810 --> 0:02:44.010 essentially mimic nature, which is what happens when a volcano blows. 0:02:44.010 --> 0:02:47.370 A big volcano blows. That's Stephen Dubner who touted the 0:02:47.410 --> 0:02:50.970 idea in his two thousand and eight book Super Freakonomics 0:02:51.290 --> 0:02:55.250 as a quick fix for global warming. In politics, the 0:02:55.330 --> 0:03:00.170 idea attracted strange bedfellows, including former Republican Speaker of the 0:03:00.210 --> 0:03:05.530 House Knut Gingrich, Texas Republican and climate science skeptic Lamar Smith, 0:03:05.970 --> 0:03:10.810 and twenty twenty Democratic presidential candidate and Drew Yang. It 0:03:10.970 --> 0:03:14.490 even made it into the Netflix comedy show The Fix, 0:03:15.130 --> 0:03:19.610 where comedian d l hugely recommended blowing up a volcano 0:03:20.090 --> 0:03:23.850 to save the world. So let's find some volcano in 0:03:23.850 --> 0:03:26.530 the middle of the ocean, far away from civilization and 0:03:26.610 --> 0:03:31.290 blow it the fu the idea, well, not blowing up volcanoes, 0:03:31.410 --> 0:03:35.530 but spreading sulfur particles to decreased solar radiation is a 0:03:35.610 --> 0:03:41.650 kind of climate intervention that some people call solar geoengineering. 0:03:42.290 --> 0:03:45.690 It's gotten enough traction that the US National Research Council 0:03:46.050 --> 0:03:49.610 organized a scientific committee to study it, and it's not 0:03:49.690 --> 0:03:54.170 just theoretical. Some Harvard scientists are planning to launch an 0:03:54.210 --> 0:03:59.090 experimental balloon to start learning how to hack the planet. 0:04:02.050 --> 0:04:06.290 Today's big question, with the climate crisis becoming more and 0:04:06.450 --> 0:04:10.450 more desperate, should we get ready to alter the atmosphere 0:04:10.530 --> 0:04:16.370 of Planet Earth? Solar geoengineering? Can it protect us from 0:04:16.370 --> 0:04:21.010 climate change? Do we need it? And what could possibly 0:04:21.090 --> 0:04:31.130 go wrong? My name is Eric Lander. I'm a scientist 0:04:31.210 --> 0:04:34.090 who works on ways to improve human health. I helped 0:04:34.170 --> 0:04:36.850 lead the Human Genome Project, and today I lead the 0:04:36.970 --> 0:04:41.050 Road Institute of MIT and Harvard. In the twenty first century, 0:04:41.410 --> 0:04:45.890 powerful technologies have been appearing at a breathtaking pace, related 0:04:45.930 --> 0:04:50.410 to the Internet, artificial intelligence, genetic engineering, and more. They 0:04:50.450 --> 0:04:54.770 have amazing potential upsides, but we can't ignore the risks 0:04:54.810 --> 0:04:57.850 that come with them. The decisions aren't just up to 0:04:57.970 --> 0:05:01.850 scientists or politicians, whether we like it or not, we 0:05:02.530 --> 0:05:05.650 all of us are the stewards of a brave new planet. 0:05:06.170 --> 0:05:14.090 This generation's choices will shape the future never before. Coming 0:05:14.170 --> 0:05:18.450 up on this episode of Brave New Planets Blocking the Sun, 0:05:19.450 --> 0:05:22.250 we'll talk to one of the leading proponents of the technology, 0:05:22.730 --> 0:05:26.290 so solar Gin My sharing ken with total confidence and 0:05:26.330 --> 0:05:28.930 this is not an overstatement for store temperatures to pre 0:05:28.930 --> 0:05:32.850 industrial We'll hear from two experts who weighed the benefits 0:05:32.930 --> 0:05:36.170 and risks for the National Academy of Sciences. I can 0:05:36.210 --> 0:05:41.850 imagine this launching climate wars. Some third party might actually 0:05:42.610 --> 0:05:46.530 get to the point where the climate in their part 0:05:46.570 --> 0:05:52.130 of the world had become intolerable and they would unilaterally 0:05:52.410 --> 0:05:59.250 decide to modify the planet's climate without consulting with anyone, 0:05:59.530 --> 0:06:02.250 and we'll speak with the executive director of Sunrise, a 0:06:02.370 --> 0:06:05.970 movement of young people working to stop climate change, about 0:06:06.050 --> 0:06:09.970 whether it's time to consider what to do if else fails. 0:06:10.090 --> 0:06:14.370 I understand the desperation. I understand the urgency. I understand 0:06:14.450 --> 0:06:17.410 that we need to kick everything into high gear. So 0:06:17.530 --> 0:06:24.810 stay with us Chapter one, Climate Crisis. To get up 0:06:24.810 --> 0:06:27.770 to speed about the climate crisis. I went down to Washington, 0:06:27.850 --> 0:06:31.090 d C. To visit one of the nation's leading scientists, 0:06:31.090 --> 0:06:34.410 someone I know well. So my name is Marsha McNutt. 0:06:35.130 --> 0:06:39.970 I am a marine geophysicist. As a geophysicist, what's the 0:06:40.090 --> 0:06:43.210 coolest thing you've been involved in? There are so many 0:06:43.650 --> 0:06:47.970 cool things that geophysicists get to do. I've been down 0:06:48.010 --> 0:06:53.210 to the bottom of the ocean to see volcanoes erupting 0:06:53.210 --> 0:06:57.010 on the seafloor. I got to stand on the South 0:06:57.090 --> 0:07:02.850 Pole on the hundredth anniversary of Amonson's first conquest. I 0:07:02.930 --> 0:07:10.170 have been to outer Mongolia with nomadic tribesmen studying the 0:07:10.610 --> 0:07:14.490 birth of mountain belts. Chief physicists get to go a 0:07:14.530 --> 0:07:19.130 lot of very unusual places and do very wonderful things. 0:07:19.850 --> 0:07:23.050 Marsha McNutt has been a professor at MIT, head of 0:07:23.050 --> 0:07:27.050 the Monterey Bay Aquarium Research Institute, director of the US 0:07:27.130 --> 0:07:30.770 Geological Survey, and the editor in chief of Science, the 0:07:30.890 --> 0:07:35.370 nation's leading scientific journal. Today, she's president of the US 0:07:35.490 --> 0:07:39.810 National Academy of Sciences, an institution created by Abraham Lincoln 0:07:39.810 --> 0:07:44.050 in eighteen sixty three to advise the US government. It 0:07:44.170 --> 0:07:48.450 prepares major reports on crucial scientific questions facing the country. 0:07:49.010 --> 0:07:51.770 I wanted to talk to Marsha McNutt because just before 0:07:51.810 --> 0:07:55.130 becoming president of the Academy in twenty and sixteen, she 0:07:55.370 --> 0:07:59.570 chaired the Academy's report on Climate intervention, and I also 0:07:59.690 --> 0:08:02.730 talked to another of the authors of that report. My 0:08:02.810 --> 0:08:05.370 name is Ray Pierre Humbert. I'm the Highey Professor of 0:08:05.410 --> 0:08:09.370 Physics at the University of Oxford. I hadn't met Ray before. 0:08:09.570 --> 0:08:13.010 He's a dead ringer for Santa Claus. He's also an 0:08:13.010 --> 0:08:16.650 expert in planets, not just our own planet, but also 0:08:16.970 --> 0:08:22.250 exo planets, the thousands of planets outside our own solar system. 0:08:22.490 --> 0:08:25.450 My favorite planet is fifty five kancre E, which is 0:08:25.490 --> 0:08:28.450 so hot it has a permanent lava ocean on the dayside. 0:08:29.930 --> 0:08:33.370 Where's that located. It's it's around the star fifty five kancres, 0:08:33.450 --> 0:08:35.650 which is not quite a visible star, but it is 0:08:35.690 --> 0:08:39.250 near the claw one of the clause of the scorpion scorpio. 0:08:41.930 --> 0:08:44.210 And that's your favorite planet. Well, let's say it's the 0:08:44.210 --> 0:08:45.890 one we're having the most fund with right now. I 0:08:45.890 --> 0:08:48.410 see it not the vacation on a It's not one 0:08:48.410 --> 0:08:51.770 of the vacation sites, unless you like lava beaches and 0:08:51.810 --> 0:08:54.410 so forth. So I talked with Marsha and Ray about 0:08:54.410 --> 0:08:57.890 the current state of climate science. Now I shouldn't have 0:08:57.930 --> 0:09:00.610 to say this, but just in case you've been living 0:09:00.610 --> 0:09:03.690 on an exo planet or in a state of deep denial, 0:09:04.370 --> 0:09:08.770 there's no serious question that climate change is real or 0:09:09.130 --> 0:09:12.010 that it's largely due to excess carbon dioxide from burning 0:09:12.050 --> 0:09:16.090 fossil fuels causing a greenhouse effect. Here's the science in 0:09:16.130 --> 0:09:20.450 a nutshell. A greenhouse lets you grow greens and green Bay, 0:09:20.450 --> 0:09:23.170 Wisconsin in the middle of the winter because the glass 0:09:23.250 --> 0:09:26.410 lets light pass through but holds the heat in. The 0:09:26.410 --> 0:09:29.850 thicker the glass, the better the heat retention. CO two 0:09:30.010 --> 0:09:32.810 does the same thing for the Earth. It lets sunlight 0:09:32.970 --> 0:09:37.250 pass but retains much of the resulting heat. CO two 0:09:37.290 --> 0:09:40.690 has been increasing sharply over the past century, two levels 0:09:40.970 --> 0:09:45.330 unprecedented in human history, and as a result, the Earth 0:09:45.410 --> 0:09:49.650 is getting hotter. The last six years ranks of the 0:09:49.730 --> 0:09:55.570 six hottest years in recorded history. There is a lot 0:09:55.650 --> 0:10:00.690 more attention to global warming amongst the public and the press, 0:10:00.850 --> 0:10:05.090 and amongst politicians, now that we are starting to see 0:10:05.090 --> 0:10:07.930 some of the effects. What we've seen with just about 0:10:07.930 --> 0:10:09.890 a degree of warming is nothing compared to what you 0:10:09.930 --> 0:10:13.690 get with the second degree of warming. Swaths of Puerto 0:10:13.770 --> 0:10:17.930 Rico underwater roads turned through raging rivers, millions of people 0:10:17.970 --> 0:10:21.650 affected by devastating floods across South Asia, his historic fires 0:10:21.730 --> 0:10:26.930 devastating Australia, more than one hundred wildfires burning in the Arctic. 0:10:27.010 --> 0:10:32.570 Firefighters in California continuing to battle some dangerous, fast moving wildfires, 0:10:32.730 --> 0:10:38.050 five of the six largest infernos in state history, because 0:10:38.370 --> 0:10:43.450 of the release of CO two into the atmosphere from 0:10:43.490 --> 0:10:49.090 the burning of fossil fuels. Primarily, we are entering basically 0:10:49.210 --> 0:10:56.170 an unknown regime of rapidly changing climate. It is very 0:10:56.210 --> 0:11:00.570 difficult for anyone looking at the data to say with 0:11:00.730 --> 0:11:06.570 any confidence that in this future that we are entering 0:11:07.130 --> 0:11:12.410 will continue to be dousive for human habitation. Once you 0:11:12.730 --> 0:11:16.810 enter that zone, you basically can't back up. The dye 0:11:16.810 --> 0:11:21.530 has already cast, and every projection shows that we have 0:11:21.610 --> 0:11:24.730 at most decades to act. What are the sort of 0:11:24.730 --> 0:11:27.970 events we expect to happen as we have more and 0:11:27.970 --> 0:11:30.810 more SEO two in the atmosphere? What do we see 0:11:30.850 --> 0:11:33.290 happening now and what do we imagine happening in the future. 0:11:33.690 --> 0:11:38.570 So what we see happening now are things like ice 0:11:38.650 --> 0:11:45.450 sheet smelting, sea level rising, more energy in the atmospheric system, 0:11:45.490 --> 0:11:52.530 which leads to more storminess, higher amounts of rainfall, stronger hurricanes. 0:11:53.250 --> 0:11:56.330 Areas of the country that used to be pleasant to 0:11:56.370 --> 0:12:01.650 live in now becoming uninhabitable because of storm surge and 0:12:02.290 --> 0:12:06.250 high tides. We're seeing death of coral reefs because the 0:12:06.330 --> 0:12:08.930 ocean's too warm for them. Some of the things that 0:12:09.330 --> 0:12:15.730 are more complicated but likely to be far more damaging 0:12:16.410 --> 0:12:24.330 are the longer droughts, the inner actions between ecosystems, things 0:12:24.530 --> 0:12:30.090 like the bloom and plankton coming earlier in the spring 0:12:30.930 --> 0:12:36.770 when the animals that need to feed on them haven't 0:12:36.890 --> 0:12:43.530 yet returned from their migration, So you basically get animals 0:12:43.610 --> 0:12:53.170 dying of starvation. Chapter two the wet bulb temperature. When 0:12:53.210 --> 0:12:58.330 scientists describe global warming, they usually talk about average temperature rise. 0:12:59.010 --> 0:13:03.210 For example, take the twenty sixteen Paris Climate Agreement. That's 0:13:03.290 --> 0:13:05.850 the UN agreements supported by one hundred and ninety four 0:13:05.890 --> 0:13:10.490 countries but sadly no longer including the United States. It 0:13:10.530 --> 0:13:15.250 aims to keep the average global temperatureize below two degrees celsius. 0:13:15.770 --> 0:13:19.130 The problem is that an average temperature rise of two 0:13:19.210 --> 0:13:23.810 degrees celsius sounds puny, even if you convert it to 0:13:24.010 --> 0:13:28.130 roughly four degrees fahrenheit. After all, temperatures can fluctuate by 0:13:28.490 --> 0:13:31.810 twenty degrees fahrenheit over the course of a day. What's 0:13:31.850 --> 0:13:35.330 the big deal? I worry that we as scientists have 0:13:35.570 --> 0:13:40.170 perhaps done a disservice to climate change by talking about 0:13:40.410 --> 0:13:46.890 average changes because the average doesn't sound so bad. But 0:13:47.290 --> 0:13:52.010 when you talk about how the extremes are likely to change, 0:13:52.570 --> 0:13:56.290 that is when it gets very scary. One of the 0:13:56.890 --> 0:14:01.970 aspects of climate change that scares me the most is 0:14:02.210 --> 0:14:08.090 if instead you measure climate change by how many days 0:14:08.410 --> 0:14:13.370 in a ser location is the temperature likely to exceed 0:14:13.690 --> 0:14:18.570 the wet bulb temperature? What's the wet bulb temperature? It's 0:14:18.610 --> 0:14:22.250 basically the difference between life and death. Your body is 0:14:22.290 --> 0:14:25.130 always generating heat, and to keep your body at a 0:14:25.250 --> 0:14:29.450 constant temperature, you need to radiate away the excess heat. 0:14:29.490 --> 0:14:32.770 If you can't, you'll die. On a cool day, it's 0:14:32.810 --> 0:14:36.170 no problem, your skin can lose heat directly to the air. 0:14:36.930 --> 0:14:39.810 But on a hot summer day, you need to sweat 0:14:40.330 --> 0:14:44.130 so the evaporation carries away the heat. Now, if the 0:14:44.250 --> 0:14:47.490 temperature and the humidity get too high, a person literally 0:14:47.530 --> 0:14:53.250 can't sweat enough to cool themselves. What's the limit. Well, 0:14:53.290 --> 0:14:56.810 at fifty percent humidity, you can't make it much past 0:14:56.850 --> 0:15:00.650 one hundred and twelve degrees in the shade. So unless 0:15:00.730 --> 0:15:06.530 that person can get to someplace that's air conditioned, they 0:15:06.570 --> 0:15:10.890 will literally overheat and suffer heat stroke. There are many 0:15:10.930 --> 0:15:15.810 places on this planet right now in India, Southeast Asia, 0:15:16.290 --> 0:15:21.530 Africa where the number of days that are exceeding the 0:15:21.610 --> 0:15:28.850 wet bulb temperature are going up dramatically every summer. We're 0:15:28.890 --> 0:15:32.690 even seeing life threatening temperatures across temperate zones in Europe, 0:15:33.130 --> 0:15:37.210 with record highs recorded in Germany, Netherlands, Britain and France, 0:15:37.770 --> 0:15:42.410 with the ladder hitting roughly one hundred and fifteen degrees fahrenheit. 0:15:43.370 --> 0:15:45.690 So a better way to think about the effective climate 0:15:45.770 --> 0:15:48.890 change might be the number of days that a region 0:15:48.970 --> 0:15:54.130 becomes uninhabitable outdoors. If you go from say one degree 0:15:54.170 --> 0:15:56.850 of warming to two degrees of warming, a lot of 0:15:56.890 --> 0:16:00.690 the damages scale linearly. If you used to have, say 0:16:00.850 --> 0:16:04.650 something like thirty days of life threatening heat waves in 0:16:04.650 --> 0:16:07.690 some place, we go to something like sixty days when 0:16:07.690 --> 0:16:11.730 you go two degrees. What would happen if we blow 0:16:11.810 --> 0:16:15.170 past two degrees celsius, it's more like a global rise 0:16:15.210 --> 0:16:18.290 of four degrees celsius. If you get to four or 0:16:18.290 --> 0:16:21.010 five degrees global mean warming, then you get to the 0:16:21.090 --> 0:16:26.930 situation where perhaps half of the earth becomes uninhabitable outdoors 0:16:26.930 --> 0:16:29.810 for mammals. Then air conditioning becomes not a matter of 0:16:29.810 --> 0:16:32.050 comfort but a matter of life support. It's like living 0:16:32.090 --> 0:16:36.690 in a space station and a power failure becomes not 0:16:36.730 --> 0:16:39.970 just a matter of inconvenience but megadeath. Of course, most 0:16:40.010 --> 0:16:43.170 people on Earth don't have access to homes with air conditioning. 0:16:43.850 --> 0:16:46.690 It's these people who will suffer. And then you also 0:16:46.690 --> 0:16:49.330 have to think about all the animals that are not 0:16:49.410 --> 0:16:51.530 going to be living in air conditioning. What happens to elephants, 0:16:51.530 --> 0:16:55.690 what happens to cattle. It's a very different world. Unfortunately, 0:16:55.850 --> 0:16:58.770 we're not making much progress on reducing CO two emissions 0:16:59.050 --> 0:17:03.130 by almost all scientific accounts. If we don't drastically change 0:17:03.170 --> 0:17:06.650 our fossil fuel consumption, we're going to blow past the 0:17:06.690 --> 0:17:10.210 target of two degrees in the Paris Agreement. The problem 0:17:10.370 --> 0:17:14.850 is it's really hard and really slow to change the 0:17:14.850 --> 0:17:20.290 world's energy systems. To move to renewables requires electrifying your 0:17:20.410 --> 0:17:24.410 energy system. That's really the only realistic way to do it. 0:17:24.930 --> 0:17:31.650 Electrifying the system requires building transmission lines. My homes in California, 0:17:31.770 --> 0:17:35.290 it can take three years just to permit a new 0:17:35.330 --> 0:17:40.130 transmission line. Replacing power plants takes even longer since they're 0:17:40.170 --> 0:17:47.810 designed to last for decades. Power grids generally evolve over 0:17:47.890 --> 0:17:53.130 a forty year time scale. So this is why many 0:17:54.250 --> 0:18:02.570 scientists and many policymakers are concerned about taking an infrastructure 0:18:02.610 --> 0:18:07.850 system that has a forty year renewal rate and trying 0:18:07.850 --> 0:18:15.090 to respond to a problem that needs immediate action. Here's 0:18:15.130 --> 0:18:18.890 where the volcano strategy comes in. We've already tampered with 0:18:18.930 --> 0:18:22.530 our atmosphere and we're starting to feel the consequences. Why 0:18:22.570 --> 0:18:24.930 not tamper some more to prevent some of the warming, 0:18:25.290 --> 0:18:28.930 saving lives and curbing suffering. That's the idea behind this 0:18:29.010 --> 0:18:33.010 type of climate intervention. Is it time to start experimenting 0:18:33.050 --> 0:18:41.930 with the technology? Chapter three, Tiny space Mirrors. I arranged 0:18:41.970 --> 0:18:44.770 to speak with Professor David Keith. He's one of the 0:18:44.850 --> 0:18:48.970 leading proponents of solar geo engineering research and he's aiming 0:18:49.010 --> 0:18:52.650 to run a small scale test. David agreed to bicycle 0:18:52.690 --> 0:18:55.090 down from Harvard to the other end of Cambridge where 0:18:55.130 --> 0:18:58.210 I work at the Broad Institute. So solar geo my 0:18:58.250 --> 0:19:01.530 sharing ken with total confidence, and this is not an 0:19:01.530 --> 0:19:05.690 overstatement for store temperatures to pre industrial Long before David 0:19:05.730 --> 0:19:09.970 started thinking about solar gew engineering, his scientific career had 0:19:10.010 --> 0:19:14.170 an unusual start. His first job was as a research 0:19:14.250 --> 0:19:17.450 assistance in the Arctic. The year I was there, we 0:19:17.450 --> 0:19:20.530 were really working on walruses and we were trying to 0:19:20.610 --> 0:19:23.490 learn how to identify them by their calls, and then 0:19:23.850 --> 0:19:26.690 we had to brand them with cattle brands that we 0:19:26.770 --> 0:19:29.330 bought in Albertic and my job as the young guy, 0:19:29.450 --> 0:19:32.050 was to carry the brands. That was the light part 0:19:32.090 --> 0:19:34.850 and the propane tank and the kind of flamethory thing 0:19:34.890 --> 0:19:37.210 that you needed to heat have the brands. I'd done 0:19:37.450 --> 0:19:41.410 way more big outside time than most people, so probably 0:19:41.410 --> 0:19:47.490 more than a thousand kilometers of kind of Arctic ski trips, expeditions. Whatever. 0:19:47.570 --> 0:19:52.170 Would you call yourself an environmentalist in this topic? This 0:19:52.250 --> 0:19:54.290 is such a big fight, you know, I feel like 0:19:54.290 --> 0:19:56.450 that's for other people to judge. But I'd say I've 0:19:56.450 --> 0:19:59.570 been to Earth First rallies and I've done our actions, 0:19:59.690 --> 0:20:02.570 and yeah, I think the short answer it would be yeah. 0:20:02.650 --> 0:20:05.690 He began studying global warming when he arrived at M 0:20:05.890 --> 0:20:09.370 team the nineteen eighties. I stumbled into this really cool 0:20:09.410 --> 0:20:13.290 group of students in between Harvard and MIT grad students 0:20:13.330 --> 0:20:15.690 who were working on climate change, both the science and 0:20:15.730 --> 0:20:19.530 public policy in an interdictminary way. Today, David focuses on 0:20:19.610 --> 0:20:26.610 solar geoengineering. He's mostly focused on stratospheric geoengineering, which is 0:20:26.650 --> 0:20:29.530 what we've been talking about, mimicking the behavior of a 0:20:29.570 --> 0:20:34.330 volcano by spraying reflective particles into the stratosphere. But there's 0:20:34.330 --> 0:20:37.970 actually several different ways of changing the Earth's solar radiation. 0:20:38.530 --> 0:20:41.810 There's the idea of brightening a certain kind of marine 0:20:41.930 --> 0:20:46.690 boundary there cloud Brighter clouds would reflect more sunlight. There's 0:20:46.690 --> 0:20:49.890 the idea of thinning a kind of serious cloud by 0:20:49.930 --> 0:20:53.650 adding silver eyedide or something like that. Whispy or clouds 0:20:53.650 --> 0:20:56.010 would trap less of the Sun's heat. And then there's 0:20:56.090 --> 0:20:59.090 space based technologies idea you could build big orbiting mirrors 0:20:59.130 --> 0:21:02.170 or what have you. To make a difference, space mirrors 0:21:02.290 --> 0:21:05.810 would need to be huge with a surface area though 0:21:05.890 --> 0:21:09.330 about the size of Greenland. It wouldn't be cheap get 0:21:09.330 --> 0:21:12.210 them into orbit. I think if you think in the 0:21:12.290 --> 0:21:15.250 next decades, I think the idea of space based stuff 0:21:15.290 --> 0:21:17.450 is ridiculous. But if you're thinking about this is something 0:21:17.490 --> 0:21:19.490 a humans do over a century or century and a half, 0:21:19.690 --> 0:21:22.890 I don't think it's crazy to think that we might 0:21:22.930 --> 0:21:25.650 do space space things. For now, though, the best approach 0:21:25.690 --> 0:21:30.730 would be stratospheric intervention, putting reflective particles into the atmosphere. 0:21:31.250 --> 0:21:34.370 You can think of them as tiny space mirrors just 0:21:34.490 --> 0:21:38.410 to the lower altitude. Planes would fly around the stratosphere, 0:21:38.530 --> 0:21:42.970 springing plumes of sulfur dioxide or similar chemicals. It would 0:21:42.970 --> 0:21:47.050 be surprisingly cost effective. The cost to kind of begin 0:21:47.130 --> 0:21:50.290 a program that's putting material quantities of staff in the 0:21:50.330 --> 0:21:53.850 stratosphere is probably just a few billion dollars the kind 0:21:53.850 --> 0:21:56.410 of climate damages we're talking about a global basis or 0:21:56.530 --> 0:21:59.370 of order a trillion a year. So the idea that 0:21:59.370 --> 0:22:01.850 a few countries spend a few billion a year, that's 0:22:01.850 --> 0:22:03.890 a small enough number. They don't think that cost is 0:22:03.930 --> 0:22:07.010 going to be the direct driver. A few billion dollars 0:22:07.050 --> 0:22:10.290 to clean up a trillion dollar mess sounds like a 0:22:10.290 --> 0:22:15.650 pretty good deal, at least on paper. What could possibly 0:22:15.690 --> 0:22:23.570 go wrong? Chapter four? What could possibly go wrong? When 0:22:23.570 --> 0:22:26.450 the National Research Council scientists set down to write a 0:22:26.450 --> 0:22:30.170 report on solar geo engineering, the first thing they realized 0:22:30.610 --> 0:22:35.170 was that calling the technology solar geo engineering might be 0:22:35.290 --> 0:22:39.490 seriously misleading. I never liked the term geo engineering myself, 0:22:39.570 --> 0:22:44.890 because engineering is term we generally apply to precise management 0:22:45.010 --> 0:22:48.610 or design to control systems that we actually understand. But 0:22:48.770 --> 0:22:51.370 what is generally called geo engineering is something that is 0:22:51.410 --> 0:22:54.210 really hard to try out, hard to resolve. The main 0:22:54.330 --> 0:23:00.250 questions about this is basically throwing up these particles into 0:23:00.330 --> 0:23:06.250 the stratosphere at the whim of the jet stream. They 0:23:06.730 --> 0:23:10.490 go where they will. It's not like a house with 0:23:10.690 --> 0:23:15.890 thermostats in every room, where you can turn this room 0:23:15.930 --> 0:23:19.890 a little cooler and maybe this one not so cool, 0:23:20.290 --> 0:23:23.210 and turn this one off because no one really needs 0:23:23.210 --> 0:23:29.130 it in this room. So we preferred the term albedo modification, 0:23:29.330 --> 0:23:32.410 even though it sounds kind of wonky. Albedo is the 0:23:32.450 --> 0:23:37.650 scientific term for the reflectivity of a planet. Unfortunately, albedo 0:23:37.730 --> 0:23:42.450 modification wouldn't mean anything to the general public. The other extreme, 0:23:42.850 --> 0:23:46.730 some people use the term hacking the planet. There's a 0:23:46.730 --> 0:23:50.130 lot of sort of techno optimism involved in the people 0:23:50.250 --> 0:23:54.370 that are doing research on this, which is very similar 0:23:54.410 --> 0:23:56.250 to the sense of pride, where you're hacking a system 0:23:56.290 --> 0:23:58.810 and it is a sort of cool thing to contemplate, 0:23:58.850 --> 0:24:00.450 And if we didn't have to live on the planet, 0:24:00.970 --> 0:24:04.370 I'd be really interested in it myself. But it is 0:24:04.410 --> 0:24:08.370 dealing with the only home that we have and has 0:24:08.450 --> 0:24:13.530 potentially really very serious consequences. Ultimately, the scientists settled on 0:24:13.570 --> 0:24:19.050 the neutral term climate intervention. I like the climate intervention 0:24:19.170 --> 0:24:21.570 because just like with interventions, and say a person who 0:24:21.570 --> 0:24:25.170 has a drug problem or whatever, you're not guaranteed to 0:24:25.210 --> 0:24:27.850 achieve the outcome that you want. You're having an intervention 0:24:27.850 --> 0:24:31.370 because you know something is wrong, but you just can't 0:24:31.410 --> 0:24:33.650 be sure that you're not going to actually make the 0:24:33.690 --> 0:24:36.650 situation worse, but you may be so desperate that you 0:24:37.050 --> 0:24:40.210 really need to do something. As the scientists dug into 0:24:40.290 --> 0:24:44.330 the problem, they recognize that the perfect climate intervention would 0:24:44.370 --> 0:24:49.690 simply be to dim the sun by one or two percent. Unfortunately, though, 0:24:49.730 --> 0:24:53.450 the Sun doesn't have a dimmer switch, and using particles 0:24:53.450 --> 0:24:57.090 to block the Sun's rays isn't quite the same thing. 0:24:57.970 --> 0:25:01.810 You can control the average global temperature, but the impact 0:25:01.890 --> 0:25:05.530 across the globe may be very uneven. If you put 0:25:05.570 --> 0:25:08.970 aerosols up in the stratosphere, tiny little particles in the stratosphere, 0:25:09.410 --> 0:25:11.770 they don't just sit there where you put them. They 0:25:11.810 --> 0:25:15.090 get blown around by the stratospheric winds, They take up water, 0:25:15.250 --> 0:25:19.330 and they get bigger. Bigger particles have different reflective properties 0:25:19.330 --> 0:25:22.650 than smaller particles. They tend to get bunched up near 0:25:22.690 --> 0:25:26.410 the poles eventually and fall out the poles. You don't 0:25:26.450 --> 0:25:30.970 necessarily get an equal distribution between the northern hemisphere and 0:25:31.050 --> 0:25:35.290 the southern hemisphere. That might have serious consequences for the 0:25:35.290 --> 0:25:39.730 Earth's climate. Modeling has shown that if the aerosols were 0:25:39.810 --> 0:25:43.650 to preferentially bunch up in one hemisphere, that actually shifts 0:25:43.690 --> 0:25:47.570 the tropical rainfall patterns into the opposite hemisphere, so you 0:25:47.610 --> 0:25:53.210 would actually create potentially serious droughts. That's one example of 0:25:53.250 --> 0:25:57.650 the sort of thing that could go wrong inadvertently. So 0:25:57.730 --> 0:26:00.330 to put it in the simplest terms, you're saying, we 0:26:00.450 --> 0:26:05.450 could put up aerosols and end up completely surprised by 0:26:05.530 --> 0:26:10.850 the winners and losers in the climate effects of that. Right, So, 0:26:10.890 --> 0:26:13.930 it's hard to guess in advance how particles will distribute 0:26:14.050 --> 0:26:17.010 in the stratosphere. They might cool certain areas of the 0:26:17.050 --> 0:26:21.930 globe but leave others vulnerable to droughts and heat waves. Moreover, 0:26:22.690 --> 0:26:26.330 it's hard to run a local field test. We can't 0:26:26.370 --> 0:26:31.810 just say, okay, we're gonna albedo modify over El Paso, Texas, 0:26:32.130 --> 0:26:36.170 and does El Paso get cooler? And what happens till 0:26:36.450 --> 0:26:41.570 El Paso's rainfall and are there any negative effects of 0:26:42.130 --> 0:26:45.170 sulfur particles falling out of the air or anything. You 0:26:45.210 --> 0:26:47.250 can't do that because once I put it up over 0:26:47.330 --> 0:26:51.130 El Paso, how long before it distributes around the world. 0:26:51.450 --> 0:26:55.010 So most of these injections have to be done near 0:26:55.050 --> 0:26:59.890 the equator because that's the best place for distribution, and 0:27:00.250 --> 0:27:06.570 they very quickly get into these stratospheric currents that distribute them, 0:27:07.050 --> 0:27:11.130 and within two years it's all dissipated, it's all gone, 0:27:11.250 --> 0:27:14.650 It all filters out, So you would have to reinject 0:27:14.690 --> 0:27:18.450 every year to two years. So one thing you can't 0:27:18.450 --> 0:27:24.210 say at least is if you're willing to tolerate a 0:27:24.290 --> 0:27:29.250 global experiment, at least it would go away. Let's pull 0:27:29.290 --> 0:27:32.570 that thread for a second. Suppose somebody were to do 0:27:33.610 --> 0:27:37.210 a global experiment for a couple of years. Now here's 0:27:37.330 --> 0:27:40.930 the issue with doing an experiment, a global experiment on 0:27:41.130 --> 0:27:48.050 albito modification. We have no idea how to attribute whatever 0:27:48.170 --> 0:27:52.850 might happen during those two years to the experiment itself 0:27:53.530 --> 0:28:02.850 versus natural variability in storminess, droughts, floods, whatever. And you 0:28:02.890 --> 0:28:07.010 can be sure anyone who might have been impacted during 0:28:07.050 --> 0:28:14.090 that period by a hurricane, a drought, a flood would say, Bingo, 0:28:14.970 --> 0:28:19.050 you did this experiment and I got flooded out of 0:28:19.050 --> 0:28:23.490 my house, or I had a hurricane take out my barn, 0:28:24.130 --> 0:28:28.690 or I had a drought that wiped out my herd 0:28:28.730 --> 0:28:32.530 of cattle. You owe me. There'd be lawsuits all over 0:28:32.610 --> 0:28:34.730 the place. There would be lawsuits all over the place, 0:28:35.490 --> 0:28:39.170 And who's going to indemnify the person who does the 0:28:39.250 --> 0:28:43.730