Trascrizione completa di Nuclear War... Total Annihilation?

00:04:49.620 --> 00:04:50.079 on fire. 75 00:04:51.699 --> 00:04:54.779 This heat from the fireball, this is actually what kills 76 00:04:54.860 --> 00:04:57.939 most people near the blast. That's what happened in Hiroshima. 77 00:04:58.649 --> 00:05:03.189 And even a few miles away, people could suffer horrible burns. 78 00:05:05.209 --> 00:05:07.910 It would be just shocking, right? I could imagine people 79 00:05:07.949 --> 00:05:11.519 being just dazed, injured, not sure what to do. 80 00:05:12.100 --> 00:05:12.620 It's eerie. 81 00:05:14.399 --> 00:05:17.329 And then the incredible heat from the fireball would create 82 00:05:17.470 --> 00:05:21.189 what's called a blast wave, this wave of intense pressure 83 00:05:21.250 --> 00:05:24.209 that would push out more than two miles away. Where 84 00:05:24.230 --> 00:05:27.970 Caitlin is, just around the corner from Wall Street, everything 85 00:05:28.170 --> 00:05:29.129 would be devastated. 86 00:05:30.129 --> 00:05:33.790 Think of this as just a punching of air coming 87 00:05:33.850 --> 00:05:35.470 out of you, just heavy, heavy air, and it's just 88 00:05:35.490 --> 00:05:37.129 going to knock lots of things down. 89 00:05:37.189 --> 00:05:38.850 And it's going to carry everything with it, like this 90 00:05:38.930 --> 00:05:41.870 police car, that hot dog stand, everything just gets blasted. 91 00:05:42.420 --> 00:05:45.970 Swept away, swept away. I mean, just at this level 92 00:05:46.009 --> 00:05:49.129 of closeness to it, yeah, just gone. Dust everywhere. 93 00:05:49.790 --> 00:05:50.129 Nothing. 94 00:05:51.009 --> 00:05:54.310 Some people might be hurled against buildings. Others could be 95 00:05:54.410 --> 00:05:58.949 crushed by them. And windows would smash for miles, hurling 96 00:05:59.120 --> 00:06:03.500 shards of glass. And Alex says that this is actually 97 00:06:03.600 --> 00:06:06.540 why American school kids were taught to hide under their 98 00:06:06.579 --> 00:06:10.120 desks to duck and cover during the Cold War. It 99 00:06:10.129 --> 00:06:13.300 was to protect them from all that glass flying everywhere, 100 00:06:13.759 --> 00:06:17.439 not from radiation. But if you're close enough to the blast, 101 00:06:18.000 --> 00:06:21.860 you will have to worry about radiation. Alex estimates that 102 00:06:21.920 --> 00:06:24.319 around three quarters of a mile from the bomb. 103 00:06:24.639 --> 00:06:26.980 Anyone around is going to be hit with this invisible 104 00:06:27.160 --> 00:06:29.259 wave of radiation. You won't know it. 105 00:06:32.019 --> 00:06:35.100 In Hiroshima and Nagasaki, for people close to the blast, 106 00:06:35.519 --> 00:06:40.910 radiation ripped through their whole bodies. destroying cells in their skin, ovaries, testes, 107 00:06:41.009 --> 00:06:44.430 blood and bones. Their hair started falling out and their 108 00:06:44.470 --> 00:06:50.389 stomach was attacked by the radiation, making them vomit. Because 109 00:06:50.449 --> 00:06:53.500 North Korea's bomb is thought to be much more powerful 110 00:06:53.540 --> 00:06:56.699 than the ones the US dropped on Japan, it's possible 111 00:06:56.779 --> 00:07:00.040 that the fireball would be so big that if you're 112 00:07:00.079 --> 00:07:02.540 close enough to the bomb to get a big bout 113 00:07:02.579 --> 00:07:06.579 of radiation, you actually wouldn't survive long enough to feel 114 00:07:06.620 --> 00:07:12.350 these effects. you would just burn almost instantly. And while 115 00:07:12.470 --> 00:07:16.180 it's difficult to predict this kind of thing, Alex estimates 116 00:07:16.329 --> 00:07:18.819 that if you set off a hydrogen bomb above the 117 00:07:18.879 --> 00:07:22.100 New York Stock Exchange, just near Wall Street, you could 118 00:07:22.139 --> 00:07:26.339 kill about half a million people and injure about one 119 00:07:26.360 --> 00:07:34.019 and a half million more. And then what happens next? 120 00:07:35.370 --> 00:07:37.829 Alex says... It won't end things. 121 00:07:38.050 --> 00:07:40.509 There will be a day after that. Not for everybody, 122 00:07:41.230 --> 00:07:44.149 but there will be. And that's the really sickening thing 123 00:07:44.189 --> 00:07:44.850 to imagine. 124 00:07:45.970 --> 00:07:49.350 Millions of people around New York would survive the blast. 125 00:07:49.569 --> 00:07:53.209 They'll be far enough away. But what do they do now? 126 00:07:53.990 --> 00:07:56.189 Do they have to leave what's left of the city? 127 00:07:56.209 --> 00:08:02.069 Will toxic radioactive fallout shower down on them? Well, before 128 00:08:02.129 --> 00:08:05.480 we go down that road... Let's just take a little detour. 129 00:08:05.740 --> 00:08:09.379 It's getting a bit heavy here. So let's look at 130 00:08:09.480 --> 00:08:15.519 how cockroaches might survive a nuclear war. Yeah, let's take 131 00:08:15.560 --> 00:08:18.730 a look at the good old cockies. Because you might 132 00:08:18.750 --> 00:08:22.589 have heard that when the nuclear apocalypse comes, one creature 133 00:08:22.829 --> 00:08:24.009 will reign supreme. 134 00:08:25.089 --> 00:08:25.790 Cockroaches. 135 00:08:27.269 --> 00:08:31.779 But is that true? Well, to find out, scientists built 136 00:08:31.920 --> 00:08:36.120 a little cockroach-sized nuclear bomb and then they exploded it 137 00:08:36.960 --> 00:08:44.440 into a little cockroach-sized city. No, not really. Instead, they 138 00:08:44.500 --> 00:08:48.269 exposed hundreds of the poor dudes to radiation. And by 139 00:08:48.370 --> 00:08:51.590 doing this, they found that cockies, on a good day, 140 00:08:52.009 --> 00:08:56.720 could handle roughly 40 times more radiation than you and I. Now, 141 00:08:58.080 --> 00:09:02.500 That might sound pretty impressive, but get this. There's a 142 00:09:02.600 --> 00:09:06.700 cheeky wasp out there that can handle nine times more 143 00:09:06.759 --> 00:09:11.990 radiation than a cockroach. And because of this, one entomologist 144

00:09:12.139 --> 00:09:23.049 called cockroaches wimps. Harsh, but fair. Still, there's something else 145 00:09:23.129 --> 00:09:26.149 out there that can handle way more radiation than both 146 00:09:26.210 --> 00:09:30.039 of them. It's a death-defying bacteria that can happily live 147 00:09:30.519 --> 00:09:32.210 in radioactive waste. 148 00:09:32.970 --> 00:09:33.190 Ha! 149 00:09:33.470 --> 00:09:40.509 Take that, you cockroach reigned supreme during an apocalypse myth. OK. 150 00:09:41.929 --> 00:09:47.879 So now, back to humans and the devastation. We know 151 00:09:48.000 --> 00:09:50.500 that if a nuclear bomb were to drop on a 152 00:09:50.539 --> 00:09:53.899 city like New York, hundreds of thousands of people would 153 00:09:53.940 --> 00:09:57.470 die almost instantly from the heat. For others, they might 154 00:09:57.490 --> 00:10:00.879 be hit by flying objects from the blast. And if 155 00:10:00.919 --> 00:10:05.679 you survive all that, the danger isn't over yet. You 156 00:10:05.759 --> 00:10:10.279 still might be hit with something, something that really freaked 157 00:10:10.370 --> 00:10:12.029 out Americans during the Cold War. 158 00:10:12.049 --> 00:10:17.490 Danger will come not just from blast or heat or 159 00:10:17.529 --> 00:10:22.110 nearby radiation effects, but also from fallout. 160 00:10:23.190 --> 00:10:23.669 Fallout. 161 00:10:24.830 --> 00:10:28.889 Fallout is radioactive material that can get swept up into 162 00:10:28.929 --> 00:10:32.429 the air after an atomic bomb and then rain down 163 00:10:32.570 --> 00:10:36.820 on cities miles away. And there are fears that fallout 164 00:10:36.860 --> 00:10:40.960 can contaminate the land and the water for years to come. 165 00:10:40.980 --> 00:10:46.419 How will you know if there is fallout? You can't hear, smell, 166 00:10:46.960 --> 00:10:51.179 taste or see the radiations. And these bits of matter 167 00:10:51.200 --> 00:10:52.860 can be dangerous. 168 00:10:57.799 --> 00:11:01.830 How dangerous, though? Well, to find out, reporter Heather Rogers 169 00:11:01.970 --> 00:11:05.110 called up Tetsuji Imanaka, who grew up in Hiroshima. 170 00:11:05.129 --> 00:11:07.409 Hello? 171 00:11:07.789 --> 00:11:08.850 Hi, Dr Imanaka. 172 00:11:08.870 --> 00:11:09.370 Hi, good morning. 173 00:11:09.409 --> 00:11:09.870 How are you? 174 00:11:10.129 --> 00:11:13.580 Tetsuji was a nuclear engineer at Kyoto University in Japan. 175 00:11:13.740 --> 00:11:18.259 He's recently retired, but had spent his career studying radioactive fallout. 176 00:11:19.149 --> 00:11:23.409 And understanding the danger of radiation had high stakes for Tetsuji, 177 00:11:23.919 --> 00:11:27.340 because his family was affected by the nuclear bomb. His 178 00:11:27.399 --> 00:11:29.559 mum was just a couple of miles away from the 179 00:11:29.600 --> 00:11:32.139 blast in Hiroshima, on the south side of the city. 180 00:11:32.659 --> 00:11:35.519 At the time of atomic bombing, my mother was in 181

00:11:35.539 --> 00:11:41.440 the south part of Hiroshima City. And she was behind 182 00:11:41.480 --> 00:11:42.220 a small hill. 183 00:11:42.840 --> 00:11:46.759 And that small hill shielded her from the blast. Being 184 00:11:46.820 --> 00:11:51.250 a nuclear engineer, Tetsuji actually calculated her dose of radiation. 185 00:11:51.879 --> 00:11:53.909 And he says she barely got any. 186 00:11:54.230 --> 00:11:58.590 Initial radiation was almost zero, I'm sure. 187 00:11:59.370 --> 00:12:03.830 Almost zero. But the morning after the bomb, Tetsuji's mum 188 00:12:04.009 --> 00:12:06.929 actually headed back into what was left of the city. 189 00:12:07.620 --> 00:12:11.080 Tetsuji's grandmother had been in Hiroshima during the explosion and 190 00:12:11.120 --> 00:12:16.669 his mum wanted to find her. Amazingly, she did. Tetsuji's 191 00:12:16.720 --> 00:12:19.919 grandma was in really bad shape, but alive. 192 00:12:20.679 --> 00:12:27.639 She felt so happy at that time. It was very strange. 193 00:12:27.700 --> 00:12:34.039 She felt, my mother told me. 194 00:12:34.100 --> 00:12:35.360 Why does that make you laugh? 195 00:12:35.580 --> 00:12:36.059 Yeah, yeah, yeah. 196 00:12:36.379 --> 00:12:41.120 This is a Japanese way. Yeah, very sad thing. So, 197 00:12:41.159 --> 00:12:45.860 so devastating. Yeah, it's difficult to say. 198 00:12:47.090 --> 00:12:49.769 Tetsuji's grandmother was so close to the bomb when it 199 00:12:49.789 --> 00:12:51.909 went off that she was exposed to a lot of 200 00:12:51.970 --> 00:12:56.649 radiation and died a week later. Now, all that radiation 201 00:12:56.850 --> 00:13:00.809 came directly from the bomb. It wasn't fallout. But to 202 00:13:00.889 --> 00:13:04.350 find out if Tetsuji's mum was safe, he needed to 203 00:13:04.409 --> 00:13:08.629 know how bad the fallout was around Hiroshima. And he 204 00:13:08.690 --> 00:13:13.370 told Heather that his mum actually didn't get exposed to 205 00:13:13.409 --> 00:13:14.179 that much of it. 206 00:13:14.629 --> 00:13:18.730 So, not so high. Two or three times CT scan. 207 00:13:19.090 --> 00:13:21.080 So it's like as if she had two or three 208 00:13:21.159 --> 00:13:22.019 CT scans. 209 00:13:22.080 --> 00:13:22.679 Yeah, yeah, yeah. 210 00:13:23.620 --> 00:13:27.759 And for the most part, fallout from Hiroshima or Nagasaki 211 00:13:28.159 --> 00:13:32.590 didn't come down in dangerous concentrations. And to understand why, 212 00:13:32.889 --> 00:13:36.070 you have to know this curious thing about nuclear bombs. 213 00:13:36.830 --> 00:13:40.029 When it comes to fallout, it matters where in the 214 00:13:40.129 --> 00:13:44.299 sky these bombs blow up. And in Hiroshima, as well 215 00:13:44.340 --> 00:13:48.399 as Nagasaki, the bombs exploded in the air, hundreds of 216 00:13:48.460 --> 00:13:48.960 meters up. 217 00:13:49.700 --> 00:13:52.960 Fireball didn't touch the ground. 218 00:13:53.620 --> 00:13:57.519 Since the fireball didn't touch the ground, Tetsuchi calculated that 219 00:13:57.580 --> 00:14:01.559 that meant a lot of the radioactive contamination didn't fall 220 00:14:01.620 --> 00:14:05.549 on the city. Instead, it went up into the atmosphere. 221 00:14:06.350 --> 00:14:09.950 So basically, the land isn't ruined, the soil isn't ruined, 222 00:14:10.009 --> 00:14:13.940 the water isn't poisoned. Is that true? 223 00:14:14.000 --> 00:14:19.629 Such case in Hiroshima, that's true. So almost radioactive material 224 00:14:20.009 --> 00:14:22.110 went up to the sky. 225 00:14:22.929 --> 00:14:27.149 Up into the sky. In fact, tiny bits of radiation 226 00:14:27.309 --> 00:14:30.389 ended up spreading out thinly all across the globe. 227 00:14:31.009 --> 00:14:37.080 Some scientists found trace of Nagasaki bombing in the Arctic. 228 00:14:37.539 --> 00:14:42.419 Yeah, radioactive particles from the Nagasaki nuclear bomb. were found 229 00:14:42.720 --> 00:14:46.320 in the Arctic. But here's what you have to know. 230 00:14:46.960 --> 00:14:51.370 These radioactive particles are found in such low doses that 231 00:14:51.399 --> 00:14:55.000 they're not believed to be harmful. There are no radioactive 232 00:14:55.070 --> 00:14:56.450 polar bears in the Arctic. 233 00:14:57.629 --> 00:14:59.570 The radiation is not dangerous now. 234 00:15:00.429 --> 00:15:03.529 And so the reason why the fallout wasn't that dangerous 235 00:15:03.629 --> 00:15:07.409 in Hiroshima and Nagasaki was because the bombs exploded in 236 00:15:07.450 --> 00:15:08.129 the sky. 237 00:15:09.210 --> 00:15:09.389 But. 238 00:15:10.019 --> 00:15:13.370 Tetsuji told Heather that if those bombs had exploded on 239 00:15:13.409 --> 00:15:17.490 the ground, it would have been a completely different story. 240 00:15:17.970 --> 00:15:21.529 The radioactive contamination would have been really bad. 241 00:15:24.600 --> 00:15:27.440 And so if that happens, then you probably can't, like 242 00:15:27.480 --> 00:15:31.519 you won't be able to grow food there. 243 00:15:32.559 --> 00:15:34.740 And why is it so bad if the fireball hits 244 00:15:34.799 --> 00:15:35.360 the ground? 245 00:15:36.179 --> 00:15:36.399 Well. 246 00:15:37.110 --> 00:15:41.389 That huge fireball is filled with radioactive particles. And when 247 00:15:41.429 --> 00:15:44.450 it hits the ground, it drags tons of soil and 248 00:15:44.570 --> 00:15:48.549 burnt rubble into its fiery blaze, which then goes up 249 00:15:48.710 --> 00:15:52.629 into the atmosphere. And because that soil and rubble is 250 00:15:52.929 --> 00:15:57.580 relatively heavy, it can fall out of the clouds as 251 00:15:57.639 --> 00:15:59.299 radioactive dust. Fall out. 252 00:15:59.360 --> 00:16:00.600 Fall out. 253 00:16:02.269 --> 00:16:05.230 We know this because during the Cold War, the USSR 254 00:16:05.409 --> 00:16:08.250 and the US dropped a bunch of test bombs and 255 00:16:08.350 --> 00:16:11.269 some were detonated really close to the ground and they 256 00:16:11.389 -->

00:16:16.879 ended up contaminating places miles and miles away. So when 257 00:16:16.919 --> 00:16:19.799 the US detonated a bomb just seven feet from the 258 00:16:19.840 --> 00:16:24.200 ground at Bikini Atoll, a strong wind blew that radioactive 259 00:16:24.279 --> 00:16:28.429 fallout onto nearby islands and it was so bad, that 260 00:16:28.509 --> 00:16:36.259 almost 300 people got acute radiation poisoning. But will the 261 00:16:36.320 --> 00:16:43.230 landscape be contaminated with radiation forever after a nuclear bomb? Well, 262 00:16:43.830 --> 00:16:46.750 while there are some types of radiation that can stick 263 00:16:46.789 --> 00:16:51.889 around for decades, most of it actually decays fairly quickly. So, 264 00:16:53.289 --> 00:16:57.019 for example, in Hiroshima... while there was this intense blast 265 00:16:57.059 --> 00:17:00.399 of radiation as soon as the bomb exploded. Just one 266 00:17:00.440 --> 00:17:04.779 day later, it was a thousand times lower. A year later, 267 00:17:05.420 --> 00:17:09.299 radiation levels in Hiroshima were pretty much back to normal. 268 00:17:13.359 --> 00:17:16.279 Tetsuji's mum ended up staying in Hiroshima her whole life. 269 00:17:16.539 --> 00:17:18.960 She had three sons and lived to the ripe age 270 00:17:19.019 --> 00:17:24.849 of 86, eventually dying of lung cancer. And it's cancer... 271 00:17:24.950 --> 00:17:27.869 So you have to wonder, could it be from the 272 00:17:27.910 --> 00:17:33.319 radiation of the bomb? After the break, the long-term effects 273 00:17:33.480 --> 00:17:37.309 of a nuclear bomb. Is cancer how it'll get you 274 00:17:37.349 --> 00:17:46.299 in the end? Hey, it's Wendy from Science Versus, and 275 00:17:46.319 --> 00:17:48.859 I want to tell you about a podcast that I love, 276 00:17:49.099 --> 00:17:52.220 Science Friday. They cover all sorts of amazing things in 277 00:17:52.259 --> 00:17:56.180 the weird and wonderful world of science, from how concussions 278 00:17:56.279 --> 00:17:59.410 affect our brain to the inner secrets of a snake 279 00:17:59.630 --> 00:18:01.869 with a spider on its tail. tail. It's a lot 280 00:18:01.910 --> 00:18:04.589 of news that you can use and some that you can't, 281 00:18:04.730 --> 00:18:07.170 but you're going to love anyway. It's hosted by Ira 282 00:18:07.210 --> 00:18:10.750 Flato and Flora Lichtman, who is an old friend of 283 00:18:10.829 --> 00:18:13.619 the show and loves a pun as much as we do. 284 00:18:13.630 --> 00:18:17.460 Science Friday is on every day, wherever you get your podcasts. 285 00:18:24.319 --> 00:18:26.519 Welcome back. We just found out that most of the 286 00:18:26.559 --> 00:18:30.000 deaths from nuclear bombs come not from the radiation, but 287 00:18:30.059 --> 00:18:34.069 from a huge fireball and even intense pressure, which can 288 00:18:34.140 --> 00:18:38.910 shatter glass for miles. There's also the danger from radioactive 289 00:18:38.990 --> 00:18:42.910 dust that could fall from

the sky. But what if 290 00:18:42.950 --> 00:18:46.470 you lived through this kind of attack, the fireball, the glass, 291 00:18:46.529 --> 00:18:52.670 the rubble? What happens years later? Because nuclear bombs can 292 00:18:52.730 --> 00:18:56.519 spew radiation across a city, and we know radiation can 293 00:18:56.559 --> 00:19:00.960 cause cancer, does that mean you and everyone you know 294 00:19:01.180 --> 00:19:02.920 will go on to get cancer? 295 00:19:03.660 --> 00:19:06.710 There's a lot of fear of radiation. When I grew up, 296 00:19:07.630 --> 00:19:09.329 this was one of the big fears in life. 297 00:19:10.190 --> 00:19:12.670 This is Eric Grant, and he's been studying the effects 298 00:19:12.710 --> 00:19:16.660 of radiation on people for decades. He's American, but he 299 00:19:16.720 --> 00:19:19.900 lives in Hiroshima and still remembers when he first came 300 00:19:19.940 --> 00:19:20.990 to the city back in 1985. 301 00:19:20.980 --> 00:19:24.809 You know, I was a bit nervous about it, actually. 302 00:19:25.029 --> 00:19:29.069 What was it like? We did this? Is that the feeling? 303 00:19:29.089 --> 00:19:33.390 I guess so. You know, it was all-out war and 304 00:19:34.849 --> 00:19:37.940 the United States dropped that bomb and a lot of 305 00:19:37.980 --> 00:19:40.640 people died and here I was. 306 00:19:41.339 --> 00:19:44.660 Eric now works at the Radiation Effects Research Foundation, which 307 00:19:44.680 --> 00:19:47.130 has a study which tracks the health of tens of 308 00:19:47.190 --> 00:19:50.519 thousands of atomic bomb survivors. And if you want to 309 00:19:50.559 --> 00:19:53.480 know if a nuclear bomb will give you cancer, this 310 00:19:53.700 --> 00:19:57.859 is the study to look at. It's been going since 1950, 311 00:19:57.859 --> 00:20:00.759 just five years after the bomb hit, making it one 312 00:20:00.839 --> 00:20:04.819 of the longest public health studies in the world. And 313 00:20:04.859 --> 00:20:07.809 it actually started out as a US military operation. 314 00:20:08.410 --> 00:20:11.430 And the United States is very anxious to learn how 315 00:20:11.589 --> 00:20:13.109 effective the weapons were. 316 00:20:13.230 --> 00:20:16.609 Wow, but it was born out of the military wanting 317 00:20:16.650 --> 00:20:20.289 to know how dangerous their weapon was. 318 00:20:20.990 --> 00:20:25.279 That's exactly right. And I think there's still some underlying resentment. 319 00:20:25.859 --> 00:20:29.019 And the way they recruited survivors for their study probably 320 00:20:29.079 --> 00:20:32.660 didn't help. Japan was still occupied by the US in 321 00:20:32.680 --> 00:20:33.220 those days. 322 00:20:33.569 --> 00:20:35.869 We did have our own fleet of Jeeps and they 323 00:20:35.930 --> 00:20:38.930 used to crawl through the city and interview people for 324 00:20:39.049 --> 00:20:40.890 where you were at the time of the bombing and 325 00:20:40.990 --> 00:20:41.930 where was your husband. 326 00:20:42.789 --> 00:20:45.509 The US military would go to these centres where people 327 00:20:45.630 --> 00:20:48.410 asked for food rations, including pregnant women. 328 00:20:49.210 --> 00:20:51.779 And when they came to that window and said, I'm pregnant, 329 00:20:51.819 --> 00:20:55.200 I'd like this extra ration of rice, people would approach 330 00:20:55.240 --> 00:20:59.579 them and say, congratulations on your pregnancy and We would 331 00:20:59.599 --> 00:21:01.619 very much like to see how your child does. 332 00:21:03.740 --> 00:21:08.500 The study ended up recruiting around 120,000 survivors and would 333 00:21:08.599 --> 00:21:12.400 eventually split from the military, tracking cancer rates in those 334 00:21:12.440 --> 00:21:17.140 survivors for decades to come. So, what has it found? 335 00:21:17.769 --> 00:21:20.250 Did the atomic bomb increase the risk of cancer for 336 00:21:20.269 --> 00:21:26.250 these people? Eric says, yes, for cancers in all sorts 337 00:21:26.289 --> 00:21:26.829 of places. 338 00:21:27.779 --> 00:21:30.400 Your lungs, for instance, or your breast or your liver. 339 00:21:31.380 --> 00:21:36.470 But there was one cancer that was spotted almost immediately. Leukemia. 340 00:21:40.369 --> 00:21:43.890 This is the first thing that they saw. Especially among children, 341 00:21:44.049 --> 00:21:46.170 you seem like you're doing great, and then five years 342 00:21:46.210 --> 00:21:49.500 later you get a leukemia. And this was considered the 343 00:21:49.619 --> 00:21:50.480 A-bomb disease. 344 00:21:51.660 --> 00:21:55.750 So leukemia showing up in kids is pretty scary. But 345 00:21:56.150 --> 00:21:59.380 the actual number of people who got leukemia as a 346 00:21:59.420 --> 00:22:02.900 result of the bomb, well, it wasn't as high as 347 00:22:02.940 --> 00:22:06.880 you might expect. Eric and his team have found that 348 00:22:07.079 --> 00:22:11.549 out of the tens of thousands of survivors, only about 349 00:22:11.549 --> 00:22:15.269 100 more people than usual got leukemia as a result 350 00:22:15.329 --> 00:22:19.789 of the bomb. So your chance of getting leukemia if 351 00:22:19.849 --> 00:22:24.319 you survived Hiroshima was actually really, really low. 352 00:22:24.849 --> 00:22:26.349 So not huge numbers. 353 00:22:26.589 --> 00:22:27.009 Wow. 354 00:22:27.349 --> 00:22:30.210 So the rates really are quite low. 355 00:22:30.329 --> 00:22:30.589 Right. 356 00:22:30.710 --> 00:22:35.250 That's right. That's exactly right. It's lower than people generally think. 357 00:22:35.970 --> 00:22:40.960 So that's leukemia. What about the other cancers? Well, Eric 358 00:22:41.019 --> 00:22:43.880 says that his study found that if you survive to 359 00:22:43.900 --> 00:22:48.480 Hiroshima or Nagasaki, your risk of cancer is about 10% 360 00:22:48.480 --> 00:22:51.619 higher than someone who's the same age as you but 361 00:22:51.660 --> 00:22:52.700 wasn't around the bomb. 362 00:22:53.539 --> 00:22:56.960

Chances are... you're not going to suffer a cancer that 363 00:22:57.000 --> 00:22:59.039 was due to the radiation exposure. 364 00:23:00.240 --> 00:23:02.809 Well, Eric wants us to be careful with this stat. 365 00:23:03.410 --> 00:23:06.650 It's an average of the survivors in his study. And 366 00:23:06.950 --> 00:23:10.529 he says that overall, the more radiation that survivors got, 367 00:23:10.829 --> 00:23:15.309 the higher their cancer risk. Plus, this study started five 368 00:23:15.349 --> 00:23:18.130 years after the bombs went off. So there's a chance 369 00:23:18.190 --> 00:23:23.380 that some people got cancer and died before it started. Still, though, 370 00:23:23.819 --> 00:23:26.980 on average, it does seem that the number of cancers 371 00:23:27.099 --> 00:23:33.680 from Hiroshima and Nagasaki was relatively low. There were other concerns, though. 372 00:23:34.220 --> 00:23:38.380 Because nobody really knew how radiation from the bomb would linger, 373 00:23:38.849 --> 00:23:41.569 there were fears that the effect of radiation could be 374 00:23:41.640 --> 00:23:44.869 passed down to the next generation, the children of the 375 00:23:44.910 --> 00:23:50.819 atomic bomb survivors, people like Tetsuji. Well, Eric's study, which 376 00:23:50.839 --> 00:23:55.380 has now followed more than 75,000 kids of survivors for 377 00:23:55.500 --> 00:24:00.079 half a century, actually can't find any increased risk of 378 00:24:00.140 --> 00:24:01.319 cancer in these kids. 379 00:24:02.380 --> 00:24:05.670 So we haven't seen those effects, which is one of 380 00:24:05.710 --> 00:24:08.130 the silver linings, I guess, with this whole story. 381 00:24:08.369 --> 00:24:14.849 From your study, it made me think that nuclear bombs 382 00:24:15.450 --> 00:24:17.509 aren't as dangerous as I had thought. 383 00:24:18.309 --> 00:24:21.250 I guess... When you think about the long-term health effects 384 00:24:21.289 --> 00:24:25.890 of the atomic bombings, you're right that radiation risks of 385 00:24:25.970 --> 00:24:29.430 cancer are not as high as initially thought. And we 386 00:24:29.490 --> 00:24:33.890 don't see generational problems. So those two things are true. 387 00:24:34.690 --> 00:24:38.910 But the initial weapon is devastating and will take out 388 00:24:39.170 --> 00:24:41.559 huge portions of populations in cities. 389 00:24:43.400 --> 00:24:45.640 OK, so from what we found out about the bombs 390 00:24:45.700 --> 00:24:49.200 in Japan, it does seem that decades later, the radiation 391 00:24:49.240 --> 00:24:53.079 they left behind wasn't as scary as we'd initially thought. 392 00:24:54.809 --> 00:24:57.569 Hiroshima and Nagasaki were bombed at the start of the 393 00:24:57.630 --> 00:25:01.549 nuclear age, though. 70 years on, it's a very different 394 00:25:01.589 --> 00:25:05.589 world that we live in. Nine nations now have nuclear weapons. 395 00:25:06.390 --> 00:25:09.289 And if one nuclear bomb got dropped, that might not 396 00:25:09.349 --> 00:25:12.579 be the end of it. It'd probably lead to retaliation. 397 00:25:13.210 --> 00:25:17.279 with more and more bombs, and maybe even an all-out 398 00:25:17.400 --> 00:25:22.240 nuclear war. And some scientists have argued that this wouldn't 399 00:25:22.420 --> 00:25:26.299 just mean devastation for the two warring nations. It could 400 00:25:26.359 --> 00:25:32.730 have serious consequences for the entire world. During the Cold War, 401 00:25:32.829 --> 00:25:35.589 this was something that Carl Sagan talked a lot about. 402 00:25:36.069 --> 00:25:37.630 Here he is speaking on CNN. 403 00:25:38.190 --> 00:25:42.730 So it now appears that that nuclear war, almost certain, 404 00:25:43.259 --> 00:25:47.059 will destroy the global civilization. And it might just possibly 405 00:25:47.079 --> 00:25:48.140 destroy the human species. 406 00:25:49.099 --> 00:25:54.759 Destroy the human species. And here's how. Some scientists thought 407 00:25:54.799 --> 00:25:57.240 that a nuclear war could lead to a world where 408 00:25:57.259 --> 00:26:00.700 the skies would turn black, the world would go cold, 409 00:26:00.799 --> 00:26:04.240 and you couldn't grow food. People would starve to death. 410 00:26:04.940 --> 00:26:08.400 It was called a nuclear winter. And during the Cold War, 411 00:26:08.500 --> 00:26:11.430 it even got the attention of Presidents Ronald Reagan and 412 00:26:11.490 --> 00:26:17.200 Mikhail Gorbachev. But is this idea of a nuclear winter 413 00:26:17.329 --> 00:26:20.970 based on good science? I mean, I know Carl Sagan 414 00:26:21.029 --> 00:26:23.829 is like a science god and stuff, but maybe he 415 00:26:23.849 --> 00:26:27.849 went off the rails with this one. Well, what is 416 00:26:27.910 --> 00:26:31.420 supposed to lead to a nuclear winter isn't radiation. 417 00:26:31.819 --> 00:26:32.579 It's actually smoke. 418 00:26:34.269 --> 00:26:37.309 You see, nuclear bombs create so much heat that they 419 00:26:37.349 --> 00:26:42.390 burn skyscrapers, houses, bridges, and all of that fire creates 420 00:26:42.569 --> 00:26:45.599 all of this smoke that then goes up into the atmosphere. 421 00:26:45.619 --> 00:26:49.059 Here's our nuclear war researcher, Alex Wellerstein, again. 422 00:26:49.539 --> 00:26:52.759 The idea is if you burn enough stuff, you'll put 423 00:26:52.799 --> 00:26:55.339 up a lot of smoke. You put up enough smoke 424 00:26:55.500 --> 00:26:57.579 and you start to reflect sunlight. 425 00:26:58.220 --> 00:27:01.710 That black smoke absorbs some of the sun's energy, so 426 00:27:01.769 --> 00:27:06.160 it can't reach Earth. 200 years ago, a big volcano 427 00:27:06.259 --> 00:27:09.299 blew up in Indonesia and it cooled the world by 428 00:27:09.359 --> 00:27:13.460 about half a degree Celsius for a year. This became 429 00:27:13.519 --> 00:27:18.059 known as the year without summer. So if the ash 430 00:27:18.200 --> 00:27:22.259 from one volcano could cool the Earth a bit, what 431

00:27:22.299 --> 00:27:25.029 would happen if you had the smoke from the fires 432 00:27:25.240 --> 00:27:27.650 of an all-out nuclear war? 433 00:27:28.230 --> 00:27:32.140 Now, will that be enough to... actually alter the climate 434 00:27:32.200 --> 00:27:34.130 and put you into a state where, like, you start 435 00:27:34.150 --> 00:27:39.130 having really cold all year round and global famines and things. 436 00:27:39.769 --> 00:27:43.900 Well, research suggests that to cause a nuclear winter, you've 437 00:27:43.940 --> 00:27:47.579 got to throw a lot of nuclear bombs, like a 438 00:27:47.849 --> 00:27:52.400 lot of nuclear bombs. One researcher from NASA calculated that 439 00:27:52.400 --> 00:27:56.359 100 Hiroshima-sized bombs would drop the temperature of the world 440 00:27:56.460 --> 00:27:59.500 by a little over a degree Celsius. That's almost two 441 00:27:59.539 --> 00:28:04.119 degrees Fahrenheit, and that would last for several years. So, bad. 442 00:28:04.829 --> 00:28:08.420 But not enough to destroy the human species. A report 443 00:28:08.460 --> 00:28:12.130 from the National Academy of Sciences said that a large-scale 444 00:28:12.190 --> 00:28:17.309 environmental catastrophe would only happen if thousands of nuclear weapons 445 00:28:17.369 --> 00:28:21.509 were detonated. The truth is, though, we don't know exactly 446 00:28:21.680 --> 00:28:24.349 how many bombs we'd need to throw the world into 447 00:28:24.390 --> 00:28:29.029 a nuclear winter. For Alex, he says even though the 448 00:28:29.069 --> 00:28:32.819 science isn't perfect here, it is good enough for us 449 00:28:32.880 --> 00:28:34.859 to start asking this question. 450 00:28:35.400 --> 00:28:38.539 Do we need thousands of nuclear weapons? Only two countries 451 00:28:38.579 --> 00:28:40.309 have thousands. Everyone else has hundreds. 452 00:28:41.150 --> 00:28:44.549 And those two countries are, of course, the US and Russia. 453 00:28:44.910 --> 00:28:49.230 It's estimated they have roughly 10,000 nuclear weapons between them. 454 00:28:50.190 --> 00:28:54.039 So theoretically, it is possible that they could plunge us 455 00:28:54.180 --> 00:28:57.980 into a nuclear winter. So when it comes to science 456 00:28:58.019 --> 00:29:04.970 versus nuclear war, does it stack up? One, if North 457 00:29:05.009 --> 00:29:08.170 Korea dropped a nuclear bomb on New York City, perhaps 458 00:29:08.450 --> 00:29:11.859 half a million people would die. mostly from the heat 459 00:29:12.000 --> 00:29:17.400 and flying fragments, not from radiation. Two, how dangerous is 460 00:29:17.519 --> 00:29:21.599 radioactive fallout? Well, it depends on where the bomb drops 461 00:29:22.000 --> 00:29:25.660 and where the wind blows. In Hiroshima and Nagasaki, the 462 00:29:25.700 --> 00:29:29.190 fallout actually wasn't that harmful. But if a bigger bomb 463 00:29:29.250 --> 00:29:32.230 detonates on land instead of air, that could be a 464 00:29:32.269 --> 00:29:36.970 different story. And three, finally, is it possible to drop 465 00:29:37.130 --> 00:29:40.680 so many bombs that the Earth becomes uninhabitable for decades 466 00:29:40.740 --> 00:29:46.240 to come? Well, if thousands of bombs were dropped, it 467 00:29:46.400 --> 00:29:49.700 might create enough smoke to affect the climate of the planet. 468 00:29:50.680 --> 00:29:54.299 And the US and Russia, they probably have enough bombs 469 00:29:54.359 --> 00:30:18.160 to do it. That's science versus nuclear war. Music written 470 00:30:18.240 --> 00:30:37.960 by Bobby Lord and Emma Munger. Thanks for recording help 471 00:30:38.019 --> 00:30:41.000 from John Wild. For this episode, we also spoke to 472 00:30:41.059 --> 00:30:45.700 Professor Richard Wakeford, Dr Richard Turco, Professor Brian Toon, Professor 473 00:30:45.799 --> 00:30:50.309 Alan Robach, Dr Dale Preston, Dr William Kennedy, Dr Jonathan D. 474 00:30:50.349 --> 00:30:53.450 Polak and a bunch of other experts on North Korea 475 00:30:53.589 --> 00:30:57.769 and nuclear weapons. Thank you so much. Also, a special 476 00:30:57.809 --> 00:31:02.069 thanks to Shigeko Sasamori and Kathleen Sullivan. And an extra 477 00:31:02.089 --> 00:31:07.150 special thanks to the Zuckerman family and Joseph Lavelle-Wilson. Next week, 478 00:31:07.369 --> 00:31:11.569 we're tackling the ketogenic diet. Can you become your best, 479 00:31:11.769 --> 00:31:15.630 healthiest self by eating bucket loads of fat? 480 00:31:16.190 --> 00:31:19.759 If a drug did everything that the ketogenic diet did, 481 00:31:20.240 --> 00:31:24.359 it would be an enormous blockbuster drug worth billions of dollars. 482 00:31:24.380 --> 00:31:27.859 I'm Wendy Zuckerman. Back to you next time.